ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Drosophila  (53)
  • evolution  (51)
  • Photosystem II  (46)
  • Springer  (146)
  • Institute of Physics
  • 1995-1999
  • 1990-1994  (146)
  • 1940-1944
  • 1993  (146)
Collection
Keywords
Publisher
Years
  • 1995-1999
  • 1990-1994  (146)
  • 1940-1944
Year
  • 1
    Electronic Resource
    Electronic Resource
    Conserving genetic variability of a wild insect population under laboratory conditions (1993)
    Springer
    Entomologia experimentalis et applicata 67 (1993), S. 233-239 
    Details
    ISSN: 1570-7458
    Keywords: inbreeding ; colonization ; isofemale line ; Drosophila ; Diptera ; Leptopilina boulardi ; Cynipidae ; Hymenoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé D. melanogaster (Meigen) a été utilisé pour tester la capacité des lignées isofemelles à conserver la variabilité génétique d'une population naturelle. Deux types d'expériences ont été réalisées. L'une a consisté à déterminer la variabilité génétique de 3 locus enzymatiques pour 32 lignées isofemelles à la première et à la 23ème génération d'élevage au laboratoire. L'autre a consisté à tester la capacité des larves à éliminer un parasitoïde par le processus d'encapsulation après 8 années d'élevage au laboratoire. D'une façon générale, certaines lignées isofemelles perdent de la variabilité durant les 23 générations de l'étude. Mais la fréquence globale des allèles reste inchangée si l'on considère l'ensemble des 32 lignées. Le seul allèle rare observé a également été conservé. Les modifications des fréquences allèliques à chacun des locus ont lieu de façon indépendante les unes des autres. La variabilité génétique d'un caractère biologique, la capacité des larves à encapsuler le parasitoïde, a également varié, mais elle a pu être restaurée à un niveau proche de la population initiale en rassemblant plusieurs individus de chacune des lignées.
    Notes: Abstract Drosophila melanogaster (Meigen) was used to test the power of isofemale lines in preserving genetic variability. We performed experiments in two ways. One series consisted of measuring the genetic variability for three enzymatic loci in 32 isofemale lines, in the first and 23rd generations of culture. In the second series, we tested the capacity of the larvae to eliminate a parasitoid by encapsulation after eight years of laboratory breeding. In general, individual isofemale lines appeared to change during the 23 generations of the study, but the global frequency of these alleles among the 32 isofemale lines stayed relatively unchanged. The only rare allele observed was also conserved. Changes in allozyme frequencies at any one locus were independent of those at other loci. Genetic variation of a biological trait, the capacity of the larvae to encapsulate a parasitoid, also changed, but it could be restored to a level close to that of the starting population by mass hybridizing together individuals of each line.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02383432
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Responses of a generalist and a specialist parasitoid (Hymenoptera: Eucoilidae) to Drosophilid larval kairomones (1993)
    Springer
    Journal of insect behavior 6 (1993), S. 615-624 
    Details
    ISSN: 1572-8889
    Keywords: Hymenoptera ; Leptopilina ; Drosophila ; semiochemicals ; kairomones ; parasitoid ; generalist ; specialist ; foraging behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Foraging parasitoids are thought to need more specific information than generalists on the presence, identity, availability, and suitability of their insect host species. In the present paper, we compare responses to host kairomones by two phylogenetically related parasitoid species that attack Drosophilidae and that differ in the width of their host range. As predicted, the behavioral response of the parasitoids to host kairomones reflected their difference in host range. The response of the specialist parasitoid Leptopilina boulardiwas restricted to contact kairomones from its natural hosts and one closely related species. In contrast, the generalist parasitoid Leptopilina heterotomaresponded to contact kairomones of a variety of Drosophilidae species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01048127
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Cockroach mating behaviors, sex pheromones, and abdominal glands (Dictyoptera: Blaberidae) (1993)
    Springer
    Journal of insect behavior 6 (1993), S. 715-735 
    Details
    ISSN: 1572-8889
    Keywords: Aphrodisiac ; cockroach ; evolution ; mating behavior ; sex pheromone ; sternal glands ; tergal glands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two chemical signals are essential in all cockroach sexual behavioral sequences: the sex pheromone released by one partner, generally the female (for long distance attraction), and an aphrodisiac sex pheromone produced exclusively by male tergal glands (for female mounting and tergal contact or “feeding” behavior). Unlike the other cockroach groups, the males of the Oxyhaloinae species produce both chemical signals: the pheromone and the aphrodisiac. The occurrence of three patterns of mating behavior (A, B, and C), the production of male sex pheromones, and the existence in the male of developed sternal and tergal glands in seven related Oxyhaloinae species, make these cockroaches a useful model for studying the evolution of mating behavior patterns. The various types of mating behavior were not classified in the previous studies by Roth and Barth. In this report, they have been named type A (female in upper position), B (male in upper position), and C (male and female end to end). In type A mating, the male tergal glands, which are licked by the females, are well developed, whereas in types B and C, there is no licking of the male's tergal secretion by the females and the tergal glands are much less developed; the aphrodisiacs secreted by the tergal glands may no longer act in this case through contact chemoreception, but through an olfactory process involving volatile components. One common sex pheromone component seems to be acetoin. I suggest that the mating behavior tends from A toward B and C during the evolutionary process with a concomitant regression of the tergal glands and changes in the aphrodisiac emission levels. The mating behavioral sequences of cockroaches (Dictyoptera) and crickets (Orthoptera) show a striking degree of similarity and are probably examples of convergent evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01201672
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Egg attendance and brooding by males of the giant water bugLethocerus medius (Guerin) in the field (Heteroptera: Belostomatidae) (1993)
    Springer
    Journal of insect behavior 6 (1993), S. 93-106 
    Details
    ISSN: 1572-8889
    Keywords: Belostomatidae ; giant water bugs ; paternal care ; eggs ; reproduction ; behavior ; brooding ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Males of the giant water bug Lethocerus medius(Guerin) typify their monobasic subfamily, the Lethocerinae, in that they do not brood eggs attached to their backs as do males of all members of the subfamily Belostomatinae. Exclusive male parental investment as expressed in the Belostomatinae is extremely rare behavior among animals, and evolution of the trait is obscure. Lethocerus mediusmales apparently remain with their mates through oviposition and are consistently found in attendance of eggs after the female has departed. This behavior may enhance paternity assurance at no cost in opportunity for polygyny. Two double clutches of eggs were found, from which we infer the potential for polygynous matings and shared parental investment. Male L. mediusbrood attended egg clutches above the surface of the water, where they may moisten them, shade them, and defend them against predation. Egg attendance/brooding by L. mediusand other Lethocerusspecies may represent a plesiomorphic state from which paternal back- brooding evolved in the Belostomatinae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01049150
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Biology of halophilic bacteria, Part II (1993)
    Springer
    Cellular and molecular life sciences 49 (1993), S. 1027-1036 
    Details
    ISSN: 1420-9071
    Keywords: Archaea (archaebacteria) ; extreme halophiles ; archaeol phospholipids ; archaeol glycolipids ; membrane function ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Archaebacteria (archaea) are comprised of three groups of prokaryotes: extreme halophiles, methanogens and thermoacidophiles (extreme thermophiles). Their membrane phospholipids and glycolipids are derived entirely from a saturated, isopranoid glycerol diether,sn-2,3-diphytanylglycerol (‘archaeol’) and/or its dimer, dibiphytanyldiglyceroltetraether (‘caldarchaeol’). In extreme halophiles, the major phospholipid is the archaeol analogue of phosphatidylglycerolmethylphosphate (PGP-Me); the glycolipids are sulfated and/or unsulfated glycosyl archaeols with diverse carbohydrate structure characteristic of taxons on the generic level. Biosynthesis of these archaeol-derived polar lipids occurs in a multienzyme, membrane-bound system that is absolutely dependent on high salt concentration (4 M). The highly complex biosynthetic pathways involve intermediates containing glycerol ether-linked C20-isoprenyl groups which are reduced to phytanyl groups to give the final saturated polar lipids. In methanogens, polar lipids are derived both from archaeol and caldarchaeol, and thermoacidophiles contain essentially only caldarchaeol-derived polar lipids. The function of these membrane polar lipids in maintaining the stability, fluidity and ionic properties of the cell membrane of extreme halophiles, as well as the evolutionary implications of the archaeol and caldarchaeol-derived structures will be discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01929909
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Chitin in the epidermal cuticle of a vertebrate (Paralipophrys trigloides, Blenniidae, Teleostei) (1993)
    Springer
    Cellular and molecular life sciences 49 (1993), S. 317-319 
    Details
    ISSN: 1420-9071
    Keywords: Chitin ; cuticle ; evolution ; vertebrates ; bony fish ; Blenniidae ; Paralipophrys trigoides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Lectin binding, endo-chitinase binding and enzymatic degradation studies show that the epidermal cuticle of the bony fishParalipophrys trigloides (Blenniidae) is chitinous. This is the first evidence that a vertebrate species possesses a chitinous tissue. Recently aXenopus gene has been identified which has significant sequence similarity to the catalytic domain of yeast chitin synthase III, a chitin producing enzyme1,2. Taken together these two findings imply that chitin synthesis capability may be a basic vertebrate feature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01923410
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Sexual isolation betweenDrosophila melanogaster females andD. simulans males. Male mating propensities versus success in hybridization (1993)
    Springer
    Cellular and molecular life sciences 49 (1993), S. 596-598 
    Details
    ISSN: 1420-9071
    Keywords: Drosophila ; hybridization ; male vigour ; male mating speed
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Genetic variation has been found in males of aD. simulans population for their eagerness to hybridize withD. melanogaster females. In a search for traits involved in this hybridization, males ofD. simulans were tested for mating speed and sexual vigour. Between-male differences were detected in both sexual traits, but no relationship was noticed between them, nor with the frequency of hybridization. Thus male mating propensities appear to be unrelated to the breakdown of sexual isolation between these sibling species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01955171
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Evolution of insect-plant relationships — a devil's advocate approach (1993)
    Springer
    Entomologia experimentalis et applicata 66 (1993), S. 3-12 
    Details
    ISSN: 1570-7458
    Keywords: evolution ; coevolution ; selection ; insect attack ; plant defense ; competition ; enemy free space ; chemoreception ; specialization ; plant recognition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Most hypotheses concerning the evolution of insect-plant relationships are based on the assumptions that, (1) phytophagous insects reduce plant fitness, and that (2) insect-plant relationships are the result of unconstrained selection. It can be shown, however, that there is little evidence to support these assumptions. As an alternative, it is proposed that the evolution of insect-plant relationships results primarily from autonomous evolutionary events; namely from heritable functional changes within the insects' nervous system that determine plant recognition and ultimately host plant specificity. These changes cannot be evoked by selective ecological agents. They originate from intrinsic changes (mutationssensu lato) within the insect genome. Ecological factors play a secondary role: by either supporting or preventing the establishment of the new genotype with the novel food preference.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02381541
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Homopolymer length variation in the Drosophila gene mastermind (1993)
    Springer
    Journal of molecular evolution 37 (1993), S. 483-495 
    Details
    ISSN: 1432-1432
    Keywords: Drosophila ; mastermind ; Gene comparison ; Triplet repeat ; Homopolymer ; Protein evolution ; Repeat length variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Runs of identical amino acids encoded by triplet repeats (homopolymers) are components of numerous proteins, yet their role is poorly understood. Large numbers of homopolymers are present in the Drosophila melanogaster mastermind (mam) protein surrounding several unique charged amino acid clusters. Comparison of mam sequences from D. virilis and D. melanogaster reveals a high level of amino acid conservation in the charged clusters. In contrast, significant divergence is found in repetitive regions resulting from numerous amino acid replacements and large insertions and deletions. It appears that repetitive regions are under less selective pressure than unique regions, consistent with the idea that homopolymers act as flexible spacers separating functional domains in proteins. Notwithstanding extensive length variation in intervening homopolymers, there is extreme conservation of the amino acid spacing of specific charge clusters. The results support a model where homopolymer length variability is constrained by natural selection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00160429
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Molecular phylogeny of Drosophila based on ribosomal RNA sequences (1993)
    Springer
    Journal of molecular evolution 37 (1993), S. 525-543 
    Details
    ISSN: 1432-1432
    Keywords: Drosophila ; Zaprionus ; Phylogeny ; Ribosomal RNA sequences
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nucleotide sequences of 72 species of Drosophilidae were determined for divergent D1 and D2 domains (representing 200 and 341 nucleotides respectively in D. melanogaster) of large ribosomal RNA, using the rRNA direct sequencing method. Molecular phylogenetic trees were reconstructed using both distance and parsimony methods and the robustness of the nodes was evaluated by the bootstrap procedure. The trees obtained by these methods revealed four main lineages or clades which do not correspond to the taxonomical hierarchy. In our results, the genus Chymomyza is associated with the subgenus Scaptodrosophila of the genus Drosophila and their cluster constitutes the most ancient clade. The two other clades are constituted of groups belonging to the subgenus Sophophora of the genus Drosophila: the so-called Neotropical clade including the willistoni and saltans groups and the obscura-melanogaster clade itself split into three lineages: (1) obscura group + ananassae subgroup, (2) montium subgroup, and (3) melanogaster + Oriental subgroups. The fourth clade, the Drosophila one, contains three lineages. D. polychaeta, D. iri, and D. fraburu are branched together and constitute the most ancient lineage; the second lineage includes the annulimana, bromeliae, dreyfusi, melanica, mesophragmatica, repleta, robusta, and virilis groups. The third lineage is composed of the immigrans and the cardini, funebris, guaramunu, guarani, histrio, pallidipennis, quinaria, and tripunctata groups. The genera Samoaia, Scaptomyza, and Zaprionus are branched within the Drosophila clade. Although these four clades appear regularly in almost all tree calculations, additional sequencing will be necessary to determine their precise relationships.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00160433
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Evolution of thedec-1 eggshell locus inDrosophila. II. Intraspecific DNA sequence analysis reveals length mutations in a repetitive region inD. melanogaster (1993)
    Springer
    Journal of molecular evolution 36 (1993), S. 536-544 
    Details
    ISSN: 1432-1432
    Keywords: Drosophila ; dec-1 eggshell gene ; Wild-type variants ; Repeated region ; DNA sequencing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Thedec-1 eggshell gene inDrosophila melanogaster encodes follicle cell proteins required for proper eggshell assembly. As shown by Southern and Northern analyses thedec-1 gene occurs in four alleles (Fcl-4) among wild-type strains. Its second exon has a distinct feature in the form of 12 repeats with 78–91 nucleotides; the first five show nearly 100% homology. DNA sequence comparison of the repeated region of the alleles revealed that the length polymorphisms are caused by changes in the numbers of the first five repeats. The results suggest that the alleles have been generated by unequal intragenic crossing-over and/or slippage during DNA replication and that the allelic length variants have arisen independently. The possiblilty that the most common allele,FC1, has a selective advantage over the other alleles is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00556358
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Conservation and change of the developmentally crucial fushi tarazu gene in Drosophila (1993)
    Springer
    Journal of molecular evolution 36 (1993), S. 315-326 
    Details
    ISSN: 1432-1432
    Keywords: Drosophila ; Fushi tarazu ; Functional constraints ; Regulatory elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have studied the evolutionary changes occurring in the noncoding regions around the developmentally important fushi tarazu (ftz) gene in a total of 11 species in the genus Drosophila. Previous molecular developmental studies have identified DNA elements both 3′ and 5′ to the coding region which are important in proper regulation of expression of the Drosophila melanogaster ftz gene. We show here that these same elements are the most evolutionarily conserved regions in the vicinity of the gene homologs. Parts of some control elements are more conserved than exonic sequences. Not only is there sequence conservation, but the relative position, orientation, and distances among the control elements remain conserved. One quite significant difference does exist between the two major subgenera studied, Sophophora and Drosophila: namely, an inversion of the ftz unit with respect to other genes in the Antennapedia complex, ANT-C. As a comparison, we applied similar analysis to a “housekeeping” gene-rosy (ry), or Xdh. In contrast, DNA sequences 5′ to the ry coding region revealed little evolutionary conservation. These studies bear out the proposition that functionally important DNA sequences remain more conserved through evolutionary time than do less functionally important sequences. This proposition could be tested in the present case because we could predict a priori from the developmental studies which DNA regions should be most conserved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00182179
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Wavelength-dependent effects of light on magnetic compass orientation in Drosophila melanogaster (1993)
    Springer
    Journal of comparative physiology 172 (1993), S. 303-308 
    Details
    ISSN: 1432-1351
    Keywords: Drosophila ; Photoreception ; Magnetoreception ; Magnetic compass orientation ; Geomagnetic field
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract 1. Wildtype Oregon-R Drosophila melanogaster were trained in the ambient magnetic field to a horizontal gradient of 365 nm light emanating from one of the 4 cardinal compass directions and were subsequently tested in a visually-symmetrical, radial 8-arm maze in which the magnetic field alignment could be varied. When tested under 365 nm light, flies exhibited consistent magnetic compass orientation in the direction from which light had emanated in training. 2. When the data were analyzed by sex, males exhibited a strong and consistent magnetic compass response while females were randomly oriented with respect to the magnetic field. 3. When tested under 500 nm light of the same quantal flux, females were again randomly oriented with respect to the magnetic field, while males exhibited a 90° clockwise shift in magnetic compass orientation relative to the trained direction. 4. This wavelength-dependent shift in the direction of magnetic compass orientation suggests that Drosophila may utilize a light-dependent magnetic compass similar to that demonstrated previously in an amphibian. However, the data do not exclude the alternative hypothesis that a change in the wavelength of light has a non-specific effect on the flies' behavior, i.e., causing the flies to exhibit a different form of magnetic orientation behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216612
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Gypsy homologous sequences inDrosophila subobscura (gypsyDS) (1993)
    Springer
    Journal of molecular evolution 36 (1993), S. 127-135 
    Details
    ISSN: 1432-1432
    Keywords: Transposable elements ; Drosophila ; Gypsy ; Horizontal transfer ; In situ hybridization ; Molecular evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Characterization of sequences homologous to theDrosophila melanogaster gypsy transposable element was carried out inDrosophila subobscura (gypsyDS). They were found to be widely distributed among natural populations of this species. From Southern blot and in situ analyses, these sequences appear to be mobile in this species.GypsyDS sequences are located in both euchromatic and heterochromatic regions. A completegypsyDS sequence was isolated from aD. subobscura genomic library, and a 1.3-kb fragment which aligns with the ORF2 of theD. melanogaster gypsy element was sequenced. Comparisons of this sequence in three species (D. subobscura, D. melanogaster, and D. virilis) indicate that there is greater similarity between theD. subobscura-D. virilis sequences than betweenD. subobscura andD. melanogaster. Molecular divergence ofgypsy sequences betweenD. virilis andD. subobscura is estimated at 16 MY, whereas the most likely divergence time of these two species is more than 60 MY. These data strongly suggest thatgypsy sequences have been horizontally transferred between these species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00166248
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Characterization of the length polymorphism in the A+T-rich region of the Drosophila obscura group species (1993)
    Springer
    Journal of molecular evolution 36 (1993), S. 214-223 
    Details
    ISSN: 1432-1432
    Keywords: Drosophila ; Mitochondrial DNA ; Length polymorphisms ; A+T-rich region ; Tandem duplicated sequences ; Nucleotide sequences ; Secondary structures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the twelve Drosophila obscura group species studied, belonging to the affinis, obscura, and pseudoobscura subgroups, the mitochondrial DNA length ranges from 15.8 to 17.2 kb. This length polymorphism is mainly due to insertions/deletions in the variable region of the A+T-rich region. In addition, one species (D. tristis) possess a tandem duplication of a 470-bp fragment that contains the replication origin. The same duplication has occurred at least twice in the Drosophila evolutionary history due to the fact that the repetition is analogous to repetitions found in the four species of the D. melanogaster complex. By comparing the nucleotide sequence of the conserved region in D. ambigua, D. obscura, D. yakuba, D. teissieri, and D. virilis, we show the presence of a secondary structure, likely implied in the replication origin, which could favor the generation of this kind of duplications. Finally, we propose that the high A and T content in the variable region of the A + T-rich region favors the formation of less-stable secondary structures, which could explain the generation of minor insertion/deletions found in this region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00160476
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Functional conservation of a glucose-repressible amylase gene promoter from Drosophila virilis in Drosophila melanogaster (1993)
    Springer
    Journal of molecular evolution 36 (1993), S. 234-242 
    Details
    ISSN: 1432-1432
    Keywords: Drosophila ; Glucose repression ; Amylase gene ; Interspecific promoter function ; Conserved cis-acting elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Previous studies have demonstrated that the expression of the α-amylase gene is repressed by dietary glucose in Drosophila melanogaster. Here, we show that the α-amylase gene of a distantly related species, D. virilis, is also subject to glucose repression. Moreover, the cloned amylase gene of D. virilis is shown to be glucose repressible when it is transiently expressed in D. melanogaster larvae. This cross-species, functional conservation is mediated by a 330-bp promoter region of the D. virilis amylase gene. These results indicate that the promoter elements required for glucose repression are conserved between distantly related Drosophila species. A sequence comparison between the amylase genes of D. virilis and D. melanogaster shows that the promoter sequences diverge to a much greater degree than the coding sequences. The amylase promoters of the two species do, however, share small clusters of sequence similarity, suggesting that these conserved cis-acting elements are sufficient to control the glucose-regulated expression of the amylase gene in the genus Drosophila.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00160478
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Nucleotide divergence of the rp49 gene region between Drosophila melanogaster and two species of the Obscura group of Drosophila (1993)
    Springer
    Journal of molecular evolution 36 (1993), S. 243-248 
    Details
    ISSN: 1432-1432
    Keywords: rp49 gene ; Drosophila ; Sequence divergence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A 2.1-kb SStI fragment including the rp49 gene and the 3′ end of the δ-serendipity gene has been cloned and sequenced in Drosophila pseudoobscura. rp49 maps at region 62 on the tip of chromosome II of this species. Both the coding and flanking regions have been aligned and compared with those of D. subobscura. There is no evidence for heterogeneity in the rate of silent substitution between the rp49 coding region and the rate of substitutions in flanking regions, the overall silent divergence per site being 0.19. Noncoding regions also differ between both species by different insertions/deletions, some of which are related to repeated sequences. The rp49 region of D. pseudoobscura shows a strong codon bias similar to those of D. subobscura and D. melanogaster. Comparison of the rates of silent (K S ) and nonsilent (K a ) substitutions of the rp49 gene and other genes completely sequenced in D. pseudoobscura and D. melanogaster confirms previous results indicating that rp49 is evolving slowly both at silent and nonsilent sites. According to the data for the rp49 region, D. pseudoobscura and D. subobscura lineages would have diverged some 9 Myr ago, if one assumes a divergence time of 30 Myr for the melanogaster and obscura groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00160479
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Evolution of regulatory genes and patterns: Relationships to evolutionary rates and to metabolic functions (1993)
    Springer
    Journal of molecular evolution 37 (1993), S. 590-599 
    Details
    ISSN: 1432-1432
    Keywords: Evolution ; Gene regulation ; Drosophila ; Adaptation ; Enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In an effort to understand the forces shaping evolution of regulatory genes and patterns, we have compared data on interspecific differences in enzyme expression patterns among the rapidly evolving Hawaiian picture-winged Drosophila to similar data on the more conservative virilis species group. Divergence of regulatory patterns is significantly more common in the former group, but cause and effect are difficult to discern. Random fixation of regulatory variants in small populations and/or during speciation may be somewhat more likely than divergence driven by selection. Within the picture-winged group, we also have compared enzymes that fulfill different metabolic roles. There are highly significant differences between individual enzymes, but no obvious correlations to functional categories.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00182745
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Developmental effects of monensin on Drosophila melanogaster (1993)
    Springer
    Development genes and evolution 203 (1993), S. 83-91 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Monensin ; Extracellular matrix ; Membrane proteins ; Morphogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Extracellular matrix and membrane proteins and their correct secretion probably are key elements in morphogenesis and differentiation in Drosophila. In this study, we have analysed the effects of monensin, a Na+-H+-ionophore which blocks normal secretion, applied during cellular blastoderm formation on further development. Normal cell morphology and intercellular contacts are lost and the extracellular matrix becomes disorganized. Gastrulation is blocked and abnormal foldings can be observed. Cuticle phenotypes showed different degrees of ventral, dorsal, head and posterior defects. The results are discussed in the context of what is known about membrane and extracellular matrix proteins in Drosophila.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00539893
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Molecular cloning and sequencing of 18S rDNA gene fragments from six different ant species (1993)
    Springer
    Insectes sociaux 40 (1993), S. 325-335 
    Details
    ISSN: 1420-9098
    Keywords: Formicidae ; social parasitism ; PCR ; 18 S ribosomal RNA ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The evolutionary relationship between socially parasitic ants and their hosts is still an unsolved problem. We have compared a 1.2 kb sequence of the 18 S ribosomal RNA genes of the parasitic antsDoronomyrmex kutteri, Harpagoxenus sublaevis andChalepoxenus muellerianus to the sequence of the host speciesLeptothorax acervorum andL. recedens (all subfamily Myrmicinae, tribe Leptothoracini) and to an out-group antCamponotus ligniperda (Formicinae). We found that parasitic species and the host species and alsoCamponotus ligniperda differ at less than 1% of the base positions of the 1.2 kb segment of the 18S rRNA gene. The sequences showed 80.3% identity to the 18 S ribosomal RNA genes of the beetleTenebrio molitor and only 66.5% to that of the dipteranDrosophila melanogaster.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01242369
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Developmental regulatory elements in the 5′ flanking DNA of the Drosophila choline acetyltransferase gene (1993)
    Springer
    Development genes and evolution 202 (1993), S. 159-169 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Choline acetyltransferase ; cis-Regulatory element ; lacZ reporter gene ; Colinergic neuron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Choline acetyltransferase (ChAT, EC 2.3.1.6) catalyzes the production of the neurotransmitter acetylcholine, and is an essential factor for neurons to be cholinergic. We have analyzed regulation of the Drosophila ChAT gene during development by examining the β-galactosidase expression pattern in transformed lines carrying different lengths of 5′ flanking DNA fused to a lacZ reporter gene. The largest fragment tested, 7.4 kb, resulted in the most extensive expression pattern in embryonic and larval nervous system and likely reflects all the cis-regulatory elements necessary for ChAT expression. We also found that 5′ flanking DNA located between 3.3 kb and 1.2 kb is essential for the reporter gene expression in most of the segmentally arranged embryonic sensory neurons as well as other distinct cells in the CNS. The existence of negative regulatory elements was suggested by the observation that differentiating photoreceptor cells in eye imaginal discs showed the reporter gene expression in several 1.2 kb and 3.3 kb transformants but not in 7.4 kb transformants. Furthermore, we have fused the 5′ flanking DNA fragments to a wild type ChAT cDNA and used these constructs to transform Drosophila with a Cha mutant background. Surprisingly, even though different amounts of 5′ flanking DNA resulted in different spatial expression patterns, all of the positively expressing cDNA transformed lines were rescued from lethality. Our results suggest that developmental expression of the ChAT gene is regulated both positively and negatively by the combined action of several elements located in the 7.4 kb upstream region, and that the more distal 5′ flanking DNA is not necessary for embryonic survival and development to adult flies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00365306
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    A late role for a subset of neurogenic genes to limit sensory precursor recruitments in Drosophila embryos (1993)
    Springer
    Development genes and evolution 202 (1993), S. 371-381 
    Details
    ISSN: 1432-041X
    Keywords: Neurogenesis ; Drosophila ; Neurogenic genes ; PNS ; Lineage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In Drosophila, mutations in a class of genes, the neurogenic genes, produce an excess of neurons. This neural hyperplasia has been attributed to the formation of more than the normal number of neuronal precursor cells at the expense of epidermal cells. In order to find out whether the neurogenic genes only act at this intial step of neurogenesis, we studied the replication pattern of the sensory organ precursor cells by monitoring BrdU incorporation in embryos mutant for Notch (N), Delta (Dl), mastermind (mam), almondex (amx), neuralized (neu), big brain (bib) and the Enhancer of split-Complex (E(spl)-C). Using temperature sensitive alleles of two of the neurogenic genes, DI and N, we also induced an acute increase of replicating sensory precursors by shifting briefly to the restricted temperature. We have found that the loss of function of all the seven neurogenic loci that were tested causes an increase in replicating sensory precursor cells, consistent with the model that these neurogenic genes normally participate in the process of restricting the number of neuronal precursors. Whereas the temporal pattern of replication appeared normal in mutants of five of the seven neurogenic loci, in N and mam embryos replicating PNS cells are present beyond the time when they normally undergo replication. Experiments with colchicine suggest that many of these late replicating cells may be newly emerging precursors and probably not additional cell divisions of already recruited precursors. Thus, different neurogenic genes may be required over different periods of time for the specification of sensory precursor cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00188736
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Tracing neurons with a kinesin-β-galactosidase fusion protein (1993)
    Springer
    Development genes and evolution 202 (1993), S. 112-122 
    Details
    ISSN: 1432-041X
    Keywords: Axon guidance ; Drosophila ; Enhancer trap ; Kinesin-lacZ ; Neural development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have analyzed the development of neuronal projections inDrosophila by fusing the gene encodingDrosophila kinesin, a microtubule-associated motor protein, toEscherichia coli lacZ, and employing the resulting chimeric protein as a reporter molecule for labelling cells by the “enhancer-trap” method. Expression of kinesin-β-galactosidase in neurons has afforded a detailed view of the morphologies and projections of neurons. The images of cells provided by this method will facilitate anatomical and genetic investigations of theDrosophila nervous system as well as other cell types.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00636536
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Embryonic origin of the imaginal discs of the head of Drosophila melanogaster (1993)
    Springer
    Development genes and evolution 203 (1993), S. 60-73 
    Details
    ISSN: 1432-041X
    Keywords: Head development ; Eye-antenna disc ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The embryonic development of the primordia of the Drosophila head was studied by using an enhancer trap line expressed in these structures from embryonic stage 13 onward. Particular attention was given to the question of how the adult head primordia relate to the larval head segments. The clypeo-labral bud to the stage 13 embryo is located at a lateral position in the labrum adjacent to the labral sensory complex (“epiphysis”). Both clypeo-labral bud and sensory complex are located anterior to the engrailed-expression domain of the labrum. Throughout late embryogenesis and the larval period, the clypeo-labral bud forms integral part of the epithelium lining the roof of the atrium. The labial disc originates from the lateral labial segment adjacent to the labial sensory complex (“hypophysis”). It partially overlaps with the labial en-domain. After head involution, the labial disc forms a small pocket in the ventro-lateral wall of the atrium. The eye-antenna disc develops from a relatively large territory occupying the dorso-posterior part of the procephalic lobe, as well as parts of the dorsal gnathal segments. Cells in this territory are greatly reduced in number by cell death during stages 12–14. After head involution, the presumptive eye-antenna disc occupies a position in the lateral-posterior part of the dorsal pouch. Evagination of this tissue occurs during the first hours after hatching. In the embryo, no en-expression is present in the presumptive eye-antenna disc. en-expression starts in three separate regions in the third instar larva.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00539891
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Photoinhibition of photosystem II in vivo is preceded by down-regulation through light-induced acidification of the lumen: Consequences for the mechanism of photoinhibition in vivo (1993)
    Springer
    Planta 189 (1993), S. 359-368 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll fluorescence ; Down-regulation ; Energy-dependent quenching ; Photoinhibition ; Photosystem II ; Spinacia ; Vigna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mechanism of photoinhibition of photosystem II (PSII) was studied in intact leaf discs of Spinacia oleracea L. and detached leaves of Vigna unguiculata L. The leaf material was exposed to different photon flux densities (PFDs) for 100 min, while non-photochemical (qN) and photochemical quenching (qp) of chlorophyll fluorescence were monitored. The ‘energy’ and redox state of PSII were manipulated quite independently of the PFD by application of different temperatures (5–20° C), [CO2] and [O2] at different PFDs. A linear or curvilinear relationship between qp and photoinhibition of PSII was observed. When [CO2] and [O2] were both low (30 μl · l−1 and 2%, respectively), PSII was less susceptible at a given qp than at ambient or higher [CO2] and photoinhibition became only substantial when qp decreased below 0.3. When high levels of energy-dependent quenching (qE) (between 0.6 and 0.8) were reached, a further increase of the PFD or a further decrease of the metabolic demand for ATP and NADPH led to a shift from qE to photoinhibitory quenching (qI). This shift indicated that photoinhibition was preceded by down-regulation through light-induced acidification of the lumen. We propose that photoinhibition took place in the centers down-regulated by qE. The shift from qE to qI occurred concomitant with qP decreasing to zero. The results clearly show that photoinhibition does not primarily depend on the photon density in the antenna, but that photoinhibition depends on the energy state of the membrane in combination with the redox balance of PSII. The results are discussed with regard to the mechanism of photoinhibition of PSII, considering, in particular, effects of light-induced acidification on the donor side of PSII. Interestingly, cold-acclimation of spinach leaves did not significantly affect the relationship between qP, qE and photoinhibition of PSII at low temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194432
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Cold-hardening-induced resistance to photoinhibition of photosynthesis in winter rye is dependent upon an increased capacity for photosynthesis (1993)
    Springer
    Planta 189 (1993), S. 150-156 
    Details
    ISSN: 1432-2048
    Keywords: Chlorotophyll fluorescence ; Cold-hardening ; Quantum yield ; Photoinhibition (resistance) ; Photosystem II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Analyses of chlorophyll fluorescence and photosynthetic oxygen evolution were conducted to understand why cold-hardened winter rye (Secale cereale L.) is more resistant to photoinhibition of photosynthesis than is non-hardened winter rye. Under similar light and temperature conditions, leaves of cold-hardened rye were able to keep a larger fraction of the PS II reaction centres in an open configuration, i.e. a higher ratio of oxidized to reduced QA (the primary, stable quinone acceptor of PSII), than leaves of non-hardened rye. Three fold-higher photon fluence rates were required for cold-hardened leaves than for non-hardened leaves in order to establish the same proportion of oxidized to reduced QA. This ability of cold-hardened rye fully accounted for its higher resistance to photoinhibition; under similar redox states of qa cold-hardened and non-hardened leaves of winter rye exhibited similar sensitivities to photoinhibition. Under given light and temperature conditions, it was the higher capacity for light-saturated photosynthesis in cold-hardened than in non-hardened leaves, which was responsible for maintaining a higher proportion of oxidized to reduced QA. This higher capacity for photosynthesis of cold-hardened leaves also explained the increased resistance of photosynthesis to photoinhibition upon cold-hardening.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00201355
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Larval parasitoid uses aggregation pheromone of adult hosts in foraging behaviour: a solution to the reliability-detectability problem (1993)
    Springer
    Oecologia 93 (1993), S. 145-148 
    Details
    ISSN: 1432-1939
    Keywords: Hymenoptera ; Eucoilidae ; Leptopilina heterotoma ; Infochemicals ; Kairomone ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Parasitoids that forage for herbivorous hosts by using infochemicals may have a problem concerning the reliability and detectability of these stimuli: host stimuli are highly reliable but not very detectable at a distance, while stimuli from the host's food are very detectable but generally not very reliable in indicating host presence. One solution to this problem is to learn to link highly detectable stimuli to reliable but not very detectable stimuli. Ample knowledge is available on how associative learning aids foraging parasitoids in the location of suitable microhabitats. However, in this paper we report on another solution to the reliability-detectability problem and present evidence for an essential, but as yet overlooked, aspect of Drosophila parasitoid ecology. For the first time it is shown that a parasitoid of Drosophila larvae spies on the communication system of adult Drosophila flies to locate potential host sites: naive parasitoids strongly respond to a volatile aggregation pheromone that is deposited in the oviposition site by recently mated female flies. Thus, the parasitoids resort to using highly detectable information from a host stage different from the one under attack (i.e. infochemical detour). The function and ecological implications of these findings are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00321204
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Female song preference and theperiod gene inDrosophila (1993)
    Springer
    Behavior genetics 23 (1993), S. 85-90 
    Details
    ISSN: 1573-3297
    Keywords: period gene ; Drosophila ; genetic coupling ; coevolution ; sexual selection ; female preference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Mutations at theperiod (per) locus inDrosophila melanogaster alter rhythmic components of the male courtship song. We have examined the mating speed of females homozygous for mutantper alleles when presented with artificial mutant songs. Mutant females retain a preference for wild-type over mutant songs, thus male song and female preference are probably under separate genetic control. In contrast,per-mutant females from an established laboratory stock which had been maintained for nearly two decades appear to have an enhanced response to the corresponding mutant song in that they no longer discriminate against mutant song. These results are discussed in terms of the “genetic coupling” and “coevolution” theories of complementarity between male and female components of communication systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01067557
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    A novel ancestral protein ofDrosophila alcohol dehydrogenase inStreptomyces? (1993)
    Springer
    Biochemical genetics 31 (1993), S. 393-407 
    Details
    ISSN: 1573-4927
    Keywords: alcohol dehydrogenases ; protein evolution ; Drosophila ; Streptomyces
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Polyclonal antibodies raised against purifiedDrosophila alcohol dehydrogenase (ADH) were used in Western blot analyses to search for structurally and/or immunologically related proteins in prokaryotes and eukaryotes. No immunological-reactive protein was detected in a flesh fly, a locust, and butterflies. Immunological similarity with the 50-kDa PQQ-glucose dehydrogenase (GluDH)-B enzyme ofAcinetobacter calcoaceticus was found, but the cross-reactivity apparently is dependent on the high hydrophilic character of this protein. Antibodies against PQQ-GluDH did not recognizeDrosophila ADH. In five of seven species of the gram-positive soil bacteria actinomycetes tested, a protein approximately 28–30 kDa in subunit size was strongly recognized by α-DADH. It is probably not one of the two proteins with known homology toDrosophila ADH,viz., theactIII gene product and 20β-hydroxysteroid dehydrogenase. The protein is present in both the soluble and the pellet-membrane fraction of the cells. The protein has a late temporal expression in surface-grown cultures and, therefore, might be involved in secondary metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02396225
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    A rice (Oryza sativa L.) cDNA encodes a protein sequence homologous to the eukaryotic ribosomal 5S RNA-binding protein (1993)
    Springer
    Plant molecular biology 23 (1993), S. 409-413 
    Details
    ISSN: 1573-5028
    Keywords: cDNA ; cloning ; rice ; L5 ; ribosomal 5 S RNA-binding protein ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A rice (Oryza sativa L.) cDNA clone coding for the cytoplasmic ribosomal protein L5, which associates with 5 S rRNA for ribosome assembly, was cloned and its nucleotide sequence was determined. The primary structure of rice L5, deduced from the nucleotide sequence, contains 294 amino acids and has intriguing features some of which are also conserved in other eucaryotic homologues. These include: four clusters of basic amino acids, one of which may serve as a nucleolar localization signal; three repeated amino acid sequences; the conservation of glycine residues. This protein was identified as the nuclear-encoded cytoplasmic ribosomal protein L5 of rice by sequence similarity to other eucaryotic ribosomal 5 S RNA-binding proteins of rat, chicken, Xenopus laevis, and Saccharomyces cerevisiae. Rice L5 shares 51 to 62% amino acid sequence identity with the homologues. A group of ribosomal proteins from archaebacteria including Methanococcus vanniellii L18 and Halobacterium cutirubrum L13, which are known to be associated with 5 S rRNA, also related to rice L5 and the other eucaryotic counterparts, suggesting an evolutionary relationship in these ribosomal 5 S RNA-binding proteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029016
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Plant aldolase: cDNA and deduced amino-acid sequences of the chloroplast and cytosol enzyme from spinach (1993)
    Springer
    Plant molecular biology 21 (1993), S. 331-340 
    Details
    ISSN: 1573-5028
    Keywords: cDNA sequences ; evolution ; fructose-1,6-bisphosphate aldolase ; Spinacia oleracea ; transit peptide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report the sequences of full-length cDNAs for the nuclear genes encoding the chloroplastic and cytosolic fructose-1,6-bisphosphate aldolase (EC 4.1.2.13) from spinach. A comparison of the deduced amino-acid sequences with one another and with published cytosolic aldolase sequences of other plants revealed that the two enzymes from spinach share only 54% homology on their amino acid level whereas the homology of the cytosolic enzyme of spinach with the known sequences of cytosolic aldolases of maize, rice and Arabidopsis range from 67 to 92%. The sequence of the chloroplastic enzyme includes a stroma-targeting N-terminal transit peptide of 46 amino acid residues for import into the chloroplast. The transit peptide exhibits essential features similar to other chloroplast transit peptides. Southern blot analysis implies that both spinach enzymes are encoded by single genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019948
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Sorghum phosphoenolpyruvate carboxylase gene family: structure, function and molecular evolution (1993)
    Springer
    Plant molecular biology 21 (1993), S. 487-502 
    Details
    ISSN: 1573-5028
    Keywords: C4 metabolism ; evolution ; GC content ; gene family ; PEPC ; Sorghum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Although housekeeping functions have been shown for the phosphoenolpyruvate carboxylase (EC 4.1.1.31, PEPC) in plants and in prokaryotes, PEPC is mainly known for its specific role in the primary photosynthetic CO2 fixation in C4 and CAM plants. We have shown that in Sorghum, a monocotyledonous C4 plant, the enzyme is encoded in the nucleus by a small multigene family. Here we report the entire nucleotide sequence (7.5 kb) of the third member (CP21) that completes the structure of the Sorghum PEPC gene family. Nucleotide composition, CpG islands and GC content of the three Sorghum PEPC genes are analysed with respect to their possible implications in the regulation of expression. A study of structure/function and phylogenetic relationships based on the compilation of all PEPC sequences known so far is presented. Data demonstrate that (1) the different forms of plant PEPC have very similar primary structures, functional and regulatory properties, (2) neither apparent amino acid sequences nor phylogenetic relationships are specific for the C4 and CAM PEPCs and (3) expression of the different genes coding for the Sorghum PEPC isoenzymes is differently regulated (i.e. by light, nitrogen source) in a spatial and temporal manner. These results suggest that the main distinguishing feature between plant PEPCs is to be found at the level of genes expression rather than in their primary structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028806
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    A correction for allele frequency estimates derived from isofemale lines (1993)
    Springer
    Biochemical genetics 31 (1993), S. 61-74 
    Details
    ISSN: 1573-4927
    Keywords: isofemale ; allele frequency estimation ; population structure ; allozyme ; microsatellites ; restriction fragment length polymorphisms ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Isofemale lines are commonly used inDrosophila and other genera for the purpose of assaying genetic variation. Isofemale lines can be kept in the laboratory for many generations before genetic work is carried out, and permit the confirmation of newly discovered alleles. A problem not realized by many workers is that the commonly used estimate of allele frequency from these lines is biased. This estimation bias occurs at all times after the first laboratory generation, regardless of whether single individuals or pooled samples are used in each well of an electrophoretic gel. This bias can potentially affect the estimation of population genetic parameters, and in the case of rare allele analysis it can cause gross overestimates of gene flow. This paper provides a correction for allele frequency estimates derived from isofemale lines for any time after the lines are established in the laboratory. When pooled samples are used, this estimator performs better than the standard estimator at all times after the first generation. The estimator is also insensitive to multiple inseminations. After the lines have drifted oneN e generations, multiple inseminations actually make the new estimator perform better than it does in singly inseminated females. Simulations show that estimates made using either estimator after the lines have drifted to fixation have a much greater error associated with their use than do those estimates made earlier in time using the correction. In general it is better to use corrected estimates of gene frequency soon after lines are established than to use uncorrected estimates made after the first laboratory generation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553601
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Genomic rearrangement of the α-globin gene complex during mammalian evolution (1993)
    Springer
    Biochemical genetics 31 (1993), S. 473-484 
    Details
    ISSN: 1573-4927
    Keywords: hydroxyacyl glutathione hydrolase (glyoxalase II) ; chromosome mapping ; evolution ; Mus musculus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In man, the gene for hydroxyacyl glutathione hydrolase (HAGH; glyoxalase II) is closely linked to the α-globin locus (HBα) on Chromosome 16. HAGH polymorphism in the mouse has now enabled the mapping of the murine homologue. Deletion mapping, congenic strain studies, and characterization of 41 recombinant inbred strains establish that the mouseHagh locus lies very close to the α-globin pseudogene (Hba-ps4) in the vicinity of the major histocompatibility locus (H-2) on chromosome 17. Several other loci have been identified previously that are also closely linked to the human α-globin locus but near the α-globin pseudogeneHba-ps4 in the mouse. These linkage relationships suggest that during the evolution of mice a translocation occurred that subdivided the α-globin locus, leaving one inactive α-globin gene still associated with theHagh locus and linked sequences, while moving and inserting the active α-globin locus and all distal sequences into an internal location on another autosome, the predecessor to mouse chromosome 11.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02426879
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Effects of the residue adjacent to the reactive serine on the substrate interactions ofDrosophila esterase 6 (1993)
    Springer
    Biochemical genetics 31 (1993), S. 259-278 
    Details
    ISSN: 1573-4927
    Keywords: serine esterase ; substrate interactions ; Drosophila ; acetylcholine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Esterase 6 fromDrosophila melanogaster is a carboxylesterase that belongs to the serine esterase multigene family. It has a basic histidine (His) at residue 187, adjacent to the reactive serine (Ser) at residue 188, whereas most other characterized members of the family have an acidic glutamate (Glu) in the equivalent position. We have used site-directedin vitro mutagenesis to replace the His codon of the esterase 6 gene with either Gln or Glu codons. The enzymes encoded by these active-site mutants and a wild-type control have been expressed, purified, and characterized. Substitution of Gln for His at position 187 has little effect on the biochemical properties of esterase 6, but the presence of Glu at this position is associated with three major differences. First, the pH optimum is increased from 7 to 9. Second, the mutant enzyme shows decreased activity for β-naphthyl esters andp-nitrophenyl acetate but has gained the ability to hydrolyze acetylthiocholine. Finally, the Gibb's free energy of activation for the enzyme is increased. These results suggest that residue 187 interacts directly with the substrate alkyl group and that this interaction is fully realized in the transition state. We further propose that the presence of His rather than Glu at position 187 in esterase 6 contributes significantly to its functional divergence from the cholinesterases and that this divergence is due to different interactions between residue 187 and the substrate alkyl group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553170
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    ADrosophila homologue of theSchizosaccharomyces pombe act2 gene (1993)
    Springer
    Biochemical genetics 31 (1993), S. 329-341 
    Details
    ISSN: 1573-4927
    Keywords: actin superfamily ; Drosophila genetics ; ATPase domain ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Diverse proteins that are 35% to 55% identical to actins have been discovered recently in yeasts, nematodes, and vertebrates. In order to study these proteins systematically and relate their functions to those of conventional actins, we are isolating the corresponding genes from the genetically tractable eukaryote,Drosophila melanogaster. Here we report the isolation and partial characterization of aDrosophila homologue of theSchizosaccharomyces pombe act2 gene. Degenerate oligonucleotide primers specifying peptides that are highly conserved within the actin protein superfamily were used in conjunction with polymerase chain reaction (PCR) to amplify a portion of theDrosophila gene that we have namedactr66B. The corresponding full-length cDNA sequence encodes a protein of 418 residues that is 65% identical to the product of theS. pombe act2 gene, 80% identical to the bovineact2 homologue, but only 48% identical to the principalDrosophila cytoplasmic actin encoded by theAct5C actin gene. Alignment of the yeast, bovine, andDrosophila actin-related proteins shows that they have four peptide insertions, relative to conventional actins, three of which are well placed to modify actin polymerization and one that is likely to perturb the binding of myosin. Locations of two of the fiveactr66B introns are conserved betweenDrosophila and yeast genes, further attesting that they evolved from a common ancestor and are likely to encode proteins having similar functions. We demonstrate that theDrosophila gene is located on the left arm of chromosome 3, within subdivision 66B. Finally, we show by RNA blot-hybridization that the gene is expressed at low levels, relative to conventional nonmuscle actin, in all developmental stages. From these and other observations we infer that the actr66B protein is a minor component of all cells, perhaps serving to modify the polymerization, structure, and dynamic behavior of actin filaments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553175
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Genomic rearrangement of the α-globin gene complex during mammalian evolution (1993)
    Springer
    Biochemical genetics 31 (1993), S. 473-484 
    Details
    ISSN: 1573-4927
    Keywords: hydroxyacyl glutathione hydrolase (glyoxalase II) ; chromosome mapping ; evolution ; Mus musculus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In man, the gene for hydroxyacyl glutathione hydrolase (HAGH; glyoxalase II) is closely linked to the α-globin locus (HBα) on Chromosome 16. HAGH polymorphism in the mouse has now enabled the mapping of the murine homologue. Deletion mapping, congenic strain studies, and characterization of 41 recombinant inbred strains establish that the mouseHagh locus lies very close to the α-globin pseudogene (Hba-ps4) in the vicinity of the major histocompatibility locus (H-2) on chromosome 17. Several other loci have been identified previously that are also closely linked to the human α-globin locus but near the α-globin pseudogeneHba-ps4 in the mouse. These linkage relationships suggest that during the evolution of mice a translocation occurred that subdivided the α-globin locus, leaving one inactive α-globin gene still associated with theHagh locus and linked sequences, while moving and inserting the active α-globin locus and all distal sequences into an internal location on another autosome, the predecessor to mouse chromosome 11.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00554074
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Effects of the residue adjacent to the reactive serine on the substrate interactions ofDrosophila esterase 6 (1993)
    Springer
    Biochemical genetics 31 (1993), S. 259-278 
    Details
    ISSN: 1573-4927
    Keywords: serine esterase ; substrate interactions ; Drosophila ; acetylcholine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Esterase 6 fromDrosophila melanogaster is a carboxylesterase that belongs to the serine esterase multigene family. It has a basic histidine (His) at residue 187, adjacent to the reactive serine (Ser) at residue 188, whereas most other characterized members of the family have an acidic glutamate (Glu) in the equivalent position. We have used site-directedin vitro mutagenesis to replace the His codon of the esterase 6 gene with either Gln or Glu codons. The enzymes encoded by these active-site mutants and a wild-type control have been expressed, purified, and characterized. Substitution of Gln for His at position 187 has little effect on the biochemical properties of esterase 6, but the presence of Glu at this position is associated with three major differences. First, the pH optimum is increased from 7 to 9. Second, the mutant enzyme shows decreased activity for β-naphthyl esters andp-nitrophenyl acetate but has gained the ability to hydrolyze acetylthiocholine. Finally, the Gibb’s free energy of activation for the enzyme is increased. These results suggest that residue 187 interacts directly with the substrate alkyl group and that this interaction is fully realized in the transition state. We further propose that the presence of His rather than Glu at position 187 in esterase 6 contributes significantly to its functional divergence from the cholinesterases and that this divergence is due to different interactions between residue 187 and the substrate alkyl group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02401822
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    ADrosophila homologue of theSchizosaccharomyces pombe act2 gene (1993)
    Springer
    Biochemical genetics 31 (1993), S. 329-341 
    Details
    ISSN: 1573-4927
    Keywords: actin superfamily ; Drosophila genetics ; ATPase domain ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Diverse proteins that are 35% to 55% identical to actins have been discovered recently in yeasts, nematodes, and vertebrates. In order to study these proteins systematically and relate their functions to those of conventional actins, we are isolating the corresponding genes from the genetically tractable eukaryote,Drosophila melanogaster. Here we report the isolation and partial characterization of aDrosophila homologue of theSchizosaccharomyces pombe act2 gene. Degenerate oligonucleotide primers specifying peptides that are highly conserved within the actin protein superfamily were used in conjunction with polymerase chain reaction (PCR) to amplify a portion of theDrosophila gene that we have namedactr66B. The corresponding full-length cDNA sequence encodes a protein of 418 residues that is 65% identical to the product of theS. pombe act2 gene, 80% identical to the bovineact2 homologue, but only 48% identical to the principalDrosophila cytoplasmic actin encoded by theAct5C actin gene. Alignment of the yeast, bovine, andDrosophila actin-related proteins shows that they have four peptide insertions, relative to conventional actins, three of which are well placed to modify actin polymerization and one that is likely to perturb the binding of myosin. Locations of two of the fiveactr66B introns are conserved betweenDrosophila and yeast genes, further attesting that they evolved from a common ancestor and are likely to encode proteins having similar functions. We demonstrate that theDrosophila gene is located on the left arm of chromosome 3, within subdivision 66B. Finally, we show by RNA blot-hybridization that the gene is expressed at low levels, relative to conventional nonmuscle actin, in all developmental stages. From these and other observations we infer that the actr66B protein is a minor component of all cells, perhaps serving to modify the polymerization, structure, and dynamic behavior of actin filaments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02401827
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Sulfite sensitivity and sulfite oxidase actiivty inDrosophila melanogaster (1993)
    Springer
    Biochemical genetics 31 (1993), S. 375-391 
    Details
    ISSN: 1573-4927
    Keywords: Drosophila ; sulfite oxidase ; molybdenum ; MoCo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The relationship between sulfite oxidase (SO) and sulfite sensitivity inDrosophila melanogaster is addressed. Significant improvements to the SO assay have provided an investigative tool which can be applied to further studies of this molybdoenzyme. Using the second-instar larval stage ofD. melanogaster, we have shown a direct relationship between measured levels of sulfite oxidase activity and the organism's ability to withstand a sulfite challenge. Implementation of a sulfite-testing procedure confirmed the documented instability of sulfite in solution and may explain some of the conflicting results reported in the SO literature. Results of the tungstate-addition experiments confirm thatDrosophila SO is a molybdoenzyme and its activity was shown to be governed by three of the four loci known to affect more than one molybdoenzyme. The ability ofD. melanogaster to withstand the application of exogenous sulfites is shown to be dependent on sulfite oxidase activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553456
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    A novel ancestral protein ofDrosophila alcohol dehydrogenase inStreptomyces? (1993)
    Springer
    Biochemical genetics 31 (1993), S. 393-407 
    Details
    ISSN: 1573-4927
    Keywords: alcohol dehydrogenases ; protein evolution ; Drosophila ; Streptomyces
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Polyclonal antibodies raised against purifiedDrosophila alcohol dehydrogenase (ADH) were used in Western blot analyses to search for structurally and/or immunologically related proteins in prokaryotes and eukaryotes. No immunological-reactive protein was detected in a flesh fly, a locust, and butterflies. Immunological similarity with the 50-kDa PQQ-glucose dehydrogenase (GluDH)-B enzyme ofAcinetobacter calcoaceticus was found, but the cross-reactivity apparently is dependent on the high hydrophilic character of this protein. Antibodies against PQQ-GluDH did not recognizeDrosophila ADH. In five of seven species of the gram-positive soil bacteria actinomycetes tested, a protein approximately 28–30 kDa in subunit size was strongly recognized by α-DADH. It is probably not one of the two proteins with known homology toDrosophila ADH,viz., theactIII gene product and 20β-hydroxysteroid dehydrogenase. The protein is present in both the soluble and the pellet-membrane fraction of the cells. The protein has a late temporal expression in surface-grown cultures and, therefore, might be involved in secondary metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553457
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Sulfite sensitivity and sulfite oxidase actiivty inDrosophila melanogaster (1993)
    Springer
    Biochemical genetics 31 (1993), S. 375-391 
    Details
    ISSN: 1573-4927
    Keywords: Drosophila ; sulfite oxidase ; molybdenum ; MoCo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The relationship between sulfite oxidase (SO) and sulfite sensitivity inDrosophila melanogaster is addressed. Significant improvements to the SO assay have provided an investigative tool which can be applied to further studies of this molybdoenzyme. Using the second-instar larval stage ofD. melanogaster, we have shown a direct relationship between measured levels of sulfite oxidase activity and the organism's ability to withstand a sulfite challenge. Implementation of a sulfite-testing procedure confirmed the documented instability of sulfite in solution and may explain some of the conflicting results reported in the SO literature. Results of the tungstate-addition experiments confirm thatDrosophila SO is a molybdoenzyme and its activity was shown to be governed by three of the four loci known to affect more than one molybdoenzyme. The ability ofD. melanogaster to withstand the application of exogenous sulfites is shown to be dependent on sulfite oxidase activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02396224
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Deletion mutations in a long hydrophilic loop in the photosystem II chlorophyll-binding protein CP43 in the cyanobacterium Synechocystis sp. PCC 6803 (1993)
    Springer
    Plant molecular biology 23 (1993), S. 123-133 
    Details
    ISSN: 1573-5028
    Keywords: Photosystem II ; cyanobacteria ; directed mutagenesis ; psbC gene product
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to investigate the role and function of the hydrophilic region between transmembrane regions V and CI in the photosystem II core antenna protein CP43, we introduced eight different deletions in psbC of Synechocystis sp; PCC 6803 resulting in a loss of 7–11 codons in evolutionary conserved domains in this region. All deletions resulted in an obligate photoheterotrophic phenotype (requirement of glucose for cell growth) and the absence of any detectable oxygen evolution activity. The various deletion mutations showed a different impact on the amount of CP43 in the thylakoid, ranging from wild-type levels of (a now slightly smaller) CP43 to no detectable CP43 at all. All deletions led to a decrease in the amount of the D1 and D2 proteins in the thylakoids with a larger effect on D2 than on D1. CP47, the other major chlorophyll-binding protein, was present in reduced but significant amounts in the thylakoid. Herbicide binding (diuron) was lost in all but one mutant indicating the PSII components are not assembled into functionally intact complexes. Fluorescence-emission spectra confirmed this notion. This indicates that the large hydrophilic loop of CP43 plays an important role in photosystem II, and even though a shortened CP43 is present in thylakoids of most mutants, functional characteristics resemble that of a mutant with interrupted psbC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00021425
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Molecular cloning and evolutionary analysis of the calcium-modulated contractile protein, centrin, in green algae and land plants (1993)
    Springer
    Plant molecular biology 23 (1993), S. 1243-1254 
    Details
    ISSN: 1573-5028
    Keywords: calcium-binding protein ; centrin ; EF hand ; evolution ; green algae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Centrin (= caltractin) is a ubiquitous, cytoskeletal protein which is a member of the EF-hand superfamily of calcium-binding proteins. A centrin-coding cDNA was isolated and characterized from the prasinophyte green alga Scherffelia dubia. Centrin PCR amplification primers were used to isolate partial, homologous cDNA sequences from the green algae Tetraselmis striata and Spermatozopsis similis. Annealing analyses suggested that centrin is a single-copy-coding region in T. striata and S. similis and other green algae studied. Centrin-coding regions from S. dubia, S. similis and T. striata encode four colinear EF-hand domains which putatively bind calcium. Phylogenetic analyses, including homologous sequences from Chlamydomonas reinhardtii and the land plant Atriplex nummularia, demonstrate that the domains of centrins are congruent and arose from the two-fold duplication of an ancestral EF hand with Domains 1+3 and Domains 2+4 clustering. The domains of centrins are also congruent with those of calmodulins demonstrating that, like calmodulin, centrin is an ancient protein which arose within the ancestor of all eukaryotes via gene duplication. Phylogenetic relationships inferred from centrin-coding region comparisons mirror results of small subunit ribosomal RNA sequence analyses suggesting that centrin-coding regions are useful evolutionary markers within the green algae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00042357
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    The Rubisco activase (rca) gene is located downstream from rbcS in Anabaena sp. strain CA and is detected in other Anabaena/Nostoc strains (1993)
    Springer
    Plant molecular biology 21 (1993), S. 753-764 
    Details
    ISSN: 1573-5028
    Keywords: Rubisco activase ; rca ; rbcLrbcS ; cyanobacteria ; expression ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A gene encoding ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase (rca) was found downstream from the rbcLrbcS operon in the heterocystous cyanobacterium Anabaena sp. strain CA. Two unknown open reading frames were shown to be located between rbcS and rca in strain CA and all the genes, rbcLrbcS, ORF1, ORF2, and rca were in the same transcriptional orientation. The deduced amino acid sequence of the Anabaena Rubisco activase showed both similarities and differences to the plant enzyme with considerable differences at the carboxy and amino termini. Proposed ATP-binding sites were conserved in the cyanobacterial protein. Recombinant cyanobacterial Rubisco activase, however, reacted with antisera to spinach Rubisco activase. Hybridization studies, using the Anabaena sp. strain CA rca gene as a heterologous probe, detected homologous sequences in heterocystous Anabaena/Nostoc strains but not in unicellular or nonheterocystous filamentous cyanobacteria, suggestive of a close evolutionary relationship of chloroplasts and heterocystous cyanobacteria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027109
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    The psbB gene cluster of the Chlamydomonas reinhardtii chloroplast: sequence and transcriptional analyses of psbN and psbH (1993)
    Springer
    Plant molecular biology 22 (1993), S. 645-658 
    Details
    ISSN: 1573-5028
    Keywords: Chlamydomonas reinhardtii ; chloroplast DNA ; transcript maturation ; 10 kDa phosphoprotein ; psbH ; psbN ; Photosystem II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have sequenced and characterized the complete psbB gene cluster of Chlamydomonas reinhardtii chloroplast DNA. Although the petB and petD genes are located elsewhere, the sequential order of psbB, ORF31, psbN and psbH is identical to that of the psbB operon in higher plants. Also, intergenic non-coding regions are much larger in the Chlamydomonas gene cluster. Northern blot analyses indicate the formation of dicistronic transcripts of psbB and ORF31 and monocistronic transcripts of psbN and psbH. It is unclear whether a psbB operon is transcribed to yield a large polycistronic precursor but northern blot analysis with total RNA from cells grown at 15°C does not detect an increased complexity of the transcripts, as has been found in studies of the psbB operon of higher plants. From primer extension and nuclease protection assays, it is apparent that 5′ and 3′ processing of the primary psbH transcript results in the accumulation of a heterogenous population of mRNAs. Northern blot analyses reveal transcription of Chlamydomonas psbN and show that its mRNA is much larger than that identified in liverwort and pea. The sequence identities of the PSII-H and PSII-N polypeptides as compared to their vascular plant counterparts is 50 to 62%. While the amino acid sequences of PSII-H and PSII-N proteins are significantly conserved, the mass of PSII-H from Chlamydomonas is significantly larger.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00047405
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Chlorophyll-proteins from maize seedlings grown under intermittent light conditions (1993)
    Springer
    Planta 191 (1993), S. 265-273 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll-protein complex (stoichiometry) ; Chloroplast development ; Intermittent light ; Photosynthetic pigment ; Photosystem II ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied the organization of the antenna system of maize (Zea mays L.) seedlings grown under intermittent light conditions for 11 d. These plants had a higher chlorophyll-a/b ratio, a higher ratio of carotenoids to chlorophyll and a lower ratio of chlorophyll to protein than plants grown in continuous light. We found all chlorophyll-protein complexes of maize to be present. However, the minor chlorophyll a/b-proteins CP29 and CP26, and to a greater extent CP24 and the major light-harvesting complex II were reduced relative to the photosystem (PS) II core-complex. Also the chlorophyll a/b-antennae of PSI were reduced relative to the reaction-centre polypeptides. When isolated by flatbed isoelectrofocussing, the chlorophyll-a/b complexes of PSII showed a higher chlorophyll-a/b ratio and a lower ratio of chlorophyll to protein than the same complexes from continuous light; additionally, they bound more carotenoids per protein than the latter. Thus the altered organization of the photosynthetic apparatus of plants from intermittent light is caused by two different factors: (i) the altered stoichiometry of chlorophyll-binding proteins and (ii) a different ratio of pigment to protein within individual chlorophyll-proteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00199759
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Transfer of dye among salivary gland cells is not affected by genetic variations of the period clock gene in Drosophila melanogaster (1993)
    Springer
    The journal of membrane biology 136 (1993), S. 333-342 
    Details
    ISSN: 1432-1424
    Keywords: Drosophila ; per mutants ; pertransgenic ; Lucifer Yellow injections ; Gap junctions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Larval salivary gland cells of Drosophila melanogaster were injected with a fluorescent dye to assess strengths of intercellular communication among such cells, as influenced by mutations at the period locus and by a per transgene. This clock gene had been reported to increase the extent of dye transfer when mutated such that it shortens the period of biological rhythms; the previous study also showed that a per-null mutant decreased the strength of transfer among salivary gland cells. Our re-examination of this feature of larval physiology—in observer-blind analyses, using the per s and per o mutants as well as two per-normal strains—revealed no appreciable differences in extents of dye transfer among these four genotypes. These results are discussed in the context of emerging findings which suggest that the period gene's product controls pacemaker functioning as an intracellularly acting entity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233672
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Operational sex ratios and sperm limitation in populations of Drosophila pachea (1993)
    Springer
    Behavioral ecology and sociobiology 33 (1993), S. 383-391 
    Details
    ISSN: 1432-0762
    Keywords: Operational sex ratio ; Maxim system ; Sperm ; Age of maturity ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Males of the cactophilic fruitfly, Drosophila pachea, produce relatively few but very large sperm, and partition their limited gamete numbers among successive mates. The present study found that males take 10 days longer than females, post-eclosion, to become sexually mature. The pattern of testes development suggests that the need to produce testes long enough to manufacture the giant sperm is the cause of the delayed male maturity. These findings generate the prediction that the operational sex ratio (OSR) of populations will be female-biased. The size, sex ratio, and OSR of natural populations were examined. In general, local populations tended to be small and sex ratios tended to be slightly male-biased. However, as predicted, the OSR of populations, at least in one season, tended to be female-biased, with an average of 2.3 receptive females for each sexually active male. Results of laboratory experiments to determine the relationship between female remating frequency and fitness, and between population OSR and productivity, suggest that natural populations with female-biased OSRs are sperm-limited. The origin and maintenance of sperm gigantism and the unusual sperm-partitioning behavior of males are discussed with respect to population structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00170253
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Genetic analysis of chromosomal region 97D2-9 of Drosophila melanogaster (1993)
    Springer
    Molecular genetics and genomics 239 (1993), S. 109-114 
    Details
    ISSN: 1617-4623
    Keywords: Drosophila ; melanogaster ; rough ; 97D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The rough homeobox gene of D. melanogaster is required for the correct patterning of the developing eye. The locus maps to cytological location 97D2-5, a region which has not been extensively characterised. As part of our genetic and molecular characterization of rough we carried out an EMS mutagenesis to generate mutants that map to the surrounding region, 97D2-9 which is deleted in Df(3R)ro-XB3. We have generated 1 visible and 13 lethal mutations which, together with the previously described Toll and ms(3)K10 loci, and other unpublished lethals, define nine complementation groups — four lethal, three semi-lethal, one visible and one male-sterile. In addition to rough, one other locus within this region, 1(3)97De, was shown to be required for formation of the normal pattern of photoreceptor cells in the compound eye.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00281608
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Pollen grain morphology ofCoris (Primulaceae) (1993)
    Springer
    Plant systematics and evolution 184 (1993), S. 89-100 
    Details
    ISSN: 1615-6110
    Keywords: Primulaceae ; Coris ; Palynology ; pollen morphology ; pollen ultrastructure ; pollenkitt ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pollen grain morphology, sculpturing, and wall ultrastructure are investigated in two species ofCoris (Primulaceae),C. monspeliensis L. andC. hispanica Lange. The study includes both acetolysed and unacetolysed pollen. No evidence of any major palynological difference is recorded between these two species, apart from a somewhat larger pollen inC. monspeliensis. However,Coris can be distinguished from the remaining members of thePrimulaceae by the conjunction of relatively large pollen grains, prominent margo, and particular tectal pattern causing a reticulate surface with minute luminal perforations decreasing towards the colpi. From both these distinctive features, and others typically primulaceous, some evolutionary considerations are inferred. Finally, the higher proportion of irregular grains inC. hispanica is interpreted in light of environmental stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00937780
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    The allopolyploid origin ofSedum rupestre subsp.rupestre (Crassulaceae) (1993)
    Springer
    Plant systematics and evolution 184 (1993), S. 195-206 
    Details
    ISSN: 1615-6110
    Keywords: Crassulaceae ; Sedum rupestre ; Chromosome numbers ; hybridization ; allopolyploidy ; chloroplast DNA RFLP ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract InSedum rupestre L. a polyploid series (x = 16) occurs in which aneuploid chromosome numbers and odd levels of ploidy prevail. The most common and widely distributed cytotype,S. rupestre subsp.rupestre, is 2n = 112. Plants resemblingS. rupestre subsp.rupestre can be obtained by hybridizing the tetraploid cytotypes ofS. forsterianum Sm. (2n = 48) andS. rupestre subsp.erectum 't Hart (2n = 64). Comparison of these artificial hybrids with their parents and a large number of plants ofS. rupestre subsp.rupestre (2n = 112) from nature showed thatS. rupestre subsp.rupestre and the artificial hybrids are morphologically indistinguishable, and intermediate betweenS. forsterianum andS. rupestre subsp.erectum. MorphologicallyS. rupestre subsp.rupestre is closer to subsp.erectum than toS. forsterianum. Chloroplast DNA restriction patterns ofS. rupestre subsp.rupestre, however, resembleS. forsterianum more closely. The combined results of the hybridization experiments, the analysis of the cpDNA restriction patterns, and the morphological variation indicate the allopolyploid origin ofS. rupestre subsp.rupestre.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00937435
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Evolution of herkogamy and gynodioecy in Moroccan species ofRomulea (Iridaceae) (1993)
    Springer
    Plant systematics and evolution 184 (1993), S. 241-257 
    Details
    ISSN: 1615-6110
    Keywords: Romulea ; Iridaceae ; Herkogamy ; gynodioecy ; reproductive systems ; biogeography ; evolution ; phenetics ; Flora of the Mediterranean ; Morocco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Herkogamy and gynodioecy were studied in the Moroccan species ofRomulea. Several types of herkogamy are shown to occur in the different species, with each type corresponding to a characteristic perianth size. The degree of differentiation between female and hermaphrodite morphs varies among the different gynodioecious species. Herkogamy is considered to have evolved prior to the development of the gynodioecious condition. An evolutionary interpretation is proposed based on the degree of herkogamy and of gynodioecy in the different species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00937438
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    A cladistic analysis of the tribeAstereae (Asteraceae) with notes on their evolution and subtribal classification (1993)
    Springer
    Plant systematics and evolution 184 (1993), S. 259-283 
    Details
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Astereae ; Cladistics ; evolution ; phylogeny ; classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract TheAstereae were surveyed and the genera arranged in 23 informal groups. The generic groups were used to sample representative genera for a cladistic analysis based on morphological characters. The resulting cladogram was used for discussion of evolution and subtribal classification within the tribe. The lower basic chromosome numbers x = 4, 5, 6, and 8 are interpreted as reductions from a primitive x = 9. The subtribeGrangeinae occupies a phylogenetically basal position as sister group to the rest of the tribe. This may be divided into two large groups, largely corresponding to the homochromousSolidagininae and to the heterochromousAsterinae sensu lato, i.e. including theBellidinae, Hinterhuberinae, Conyzinae, andBaccharidinae. The latter four subtribes are derived within theAsterinae, and hence reduced to synonymy. Several intercontinental relationships indicate that a geographical subdivision of the tribe should be avoided, although in our analysis most of the groups proved to be restricted to one of five major regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00937439
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Alkaloids of theSedum acre-group (Crassulaceae) (1993)
    Springer
    Plant systematics and evolution 185 (1993), S. 207-217 
    Details
    ISSN: 1615-6110
    Keywords: Crassulaceae ; Sedum acre ; S. samium ; S. litoreum ; S. ser.Alpestria ; Chemotaxonomy ; pyrrolidine alkaloids ; piperidine alkaloids ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The 16 species of theSedum acre-group were investigated for the presence of alkaloids. They areS. acre ofS. ser.Acria, S. alpestre, S. annuum, S. apoleipon, S. borissovae, S. euxinum, S. grisebachii, S. laconicum, S. multiceps, S. sexangulare, S. tuberiferum, S. tuberosum, S. ursi, andS. urvillei ofS. ser.Alpestria, S. samium ofS. ser.Samia, andS. litoreum ofS. ser.Litorea. S. acre differs significantly from the other species. It contains sedamine, “hydroxy” sedamine, and a number of 2,6-disubstituted piperidine alkaloids. The leafy parts of the species ofS. ser.Alpestria, S. ser.Samia, andS. ser.Litorea contain 4 piperidine alkaloids which also occur inS. acre, and in addition 4 pyrrolidine alkaloids not present inS. acre. The composition of the alkaloid fraction agrees with the infrageneric classification (series) based on the hybridization patterns of the species (comparia).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00937658
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Non-reductional meiosis in aTriticum turgidum ×Aegilops longissima hybrid and in backcrosses of its amphidiploid withT. turgidum (Poaceae) (1993)
    Springer
    Plant systematics and evolution 187 (1993), S. 127-134 
    Details
    ISSN: 1615-6110
    Keywords: Poaceae ; Triticum ; Aegilops ; Hybrids ; amphidiploids ; meiotic non-reduction ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Meiosis was studied in aT. turgidum ×Ae. longissima hybrid (ABS1, 2n = 21) and in backcrosses of its amphidiploid toT. turgidum. Analysis of PMCs of the hybrid showed that non-reductional meiosis led to the production of a large number of non-reduced male gametes. The hybrid showed high seed set. All progeny had 2n = 42. The BC1 plants (2n = 35, AABBS1) showed the expected meiotic pairing of 14II + 7I. At anaphase I, univalents behaved in a non-reductional way. The possible role of meiotic non-reduction is discussed in terms of the evolution of theTriticum-Aegilops complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00994095
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    A phylogenetic analysis of the lichen familySphaerophoraceae (Caliciales); a new generic classification and notes on character evolution (1993)
    Springer
    Plant systematics and evolution 187 (1993), S. 213-241 
    Details
    ISSN: 1615-6110
    Keywords: Ascomycetes ; Bunodophoron ; Caliciales ; Calycidium ; Leifidium ; Sphaerophoraceae ; Sphaerophorus ; Cladistics ; classification ; evolution ; systematics ; phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A phylogenetic analysis of the familySphaerophoraceae (Caliciales, lichenized ascomycetes) has resulted in a new generic classification. Notes on character evolution are given. The generaSphaerophorus s. str.,Bunodophoron andLeifidium, gen. nov., are accepted.Pleurocybe andPseudosphaerophorus are considered synonyms ofBunodophoron andThysanophoron is considered synonym toSphaerophorus. The following new combinations are proposed:Bunodophoron coomerense (Ohlsson)Wedin,B. diplotypum (Vain.)Wedin,B. dodgei (Ohlsson)Wedin,B. flaccidum (Kantvilas & Wedin)Wedin,B. formosanum (Zahlbr.)Wedin,B. imshaugii (Ohlsson)Wedin,B. insigne (Laurer)Wedin,B. kinabaluense (M. Satô)Wedin,B. macrocarpum (Ohlsson)Wedin,B. madagascareum (Nyl.)Wedin,B. microsporum (Ohlsson)Wedin,B. murrayi (Ohlsson)Wedin,B. notatum (Tibell)Wedin,B. ohlssonii (Wedin)Wedin,B. patagonicum (C. W. Dodge)Wedin,B. ramuliferum (I. M. Lamb)Wedin,B. scrobiculatum (C. Bab.)Wedin,B. tibellii (Wedin)Wedin,B. whakapapaense (Wedin)Wedin, andLeifidium tenerum (Laurer)Wedin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00994100
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Chloroplast DNA-based phylogeny of AsianPinus species (Pinaceae) (1993)
    Springer
    Plant systematics and evolution 188 (1993), S. 197-211 
    Details
    ISSN: 1615-6110
    Keywords: Gymnosperms ; Pinaceae ; Pinus ; cpDNA variation ; molecular systematics ; evolution ; Flora of Eurasia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The genusPinus includes over 90 species with approximately 24 species native to Asia. We have analyzed the chloroplast (cp) DNA variation of 18Pinus species, including 15 Asian, two Eurasian, and one European species using seven restriction enzymes and ten non-overlapping probes and inferred their phylogenetic relationships. Results of phenetic and cladistic approaches to phylogeny reconstruction were largely in agreement, suggesting two major lineages within the genus and confirmed the ancient character of haploxylon and diploxylon subgenera. Species from sectionParrya appear to have diverged earliest from the hypothesized phylogenetic centre for the haploxylon pines, withP. bungeana andP. gerardiana forming two basal, monotypic lineages. The range of estimated pairwise nucleotide substitutions per site ( $$\mathop d\limits^ \sim $$ ) was higher among haploxylon pines than among diploxylon species. CpDNA divergence was found to be low within the sectionSylvestres, relative to the divergence among haploxylon species, suggesting that the radiation of this group of taxa from its common ancestor occurred after the diversification of other groups. The low cpDNA divergence in this subsection corroborated earlier evidence for its phylogenetic cohesiveness and existence as a monophyletic group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00937728
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Analysing the responses of photosynthetic CO2 assimilation to long-term elevation of atmospheric CO2 concentration (1993)
    Springer
    Plant ecology 104-105 (1993), S. 33-45 
    Details
    ISSN: 1573-5052
    Keywords: Greenhouse effect ; Chlorophyll fluorescence ; RubisCQ ; Photosystem II ; Stomata ; Quantum efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Understanding how photosynthetic capacity acclimatises when plants are grown in an atmosphere of rising CO2 concentrations will be vital to the development of mechanistic models of the response of plant productivity to global environmental change. A limitation to the study of acclimatisation is the small amount of material that may be destructively harvested from long-term studies of the effects of elevation of CO2 concentration. Technological developments in the measurement of gas exchange, fluorescence and absorption spectroscopy, coupled with theoretical developments in the interpretation of measured values now allow detailed analyses of limitations to photosynthesisin vivo. The use of leaf chambers with Ulbricht integrating spheres allows separation of change in the maximum efficiency of energy transduction in the assimilation of CO2 from changes in tissue absorptance. Analysis of the response of CO2 assimilation to intercellular CO2 concentration allows quantitative determination of the limitation imposed by stomata, carboxylation efficiency, and the rate of regeneration of ribulose 1:5 bisphosphate. Chlorophyll fluorescence provides a rapid method for detecting photoinhibition in heterogeneously illuminated leaves within canopies in the field. Modulated fluorescence and absorption spectroscopy allow parallel measurements of the efficiency of light utilisation in electron transport through photosystems I and IIin situ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00048143
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    A note on functional implications of morphological variation in the human mandible (1993)
    Springer
    International journal of anthropology 8 (1993), S. 53-60 
    Details
    ISSN: 1824-3096
    Keywords: mandible ; evolution ; function ; morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This study was carried out on 56 mandibles belonging to skeletal remains recovered from archaeological excavations in Israel dated to 6.000 BP. or less, 2 Neandertal mandibles dating between 50.000–60.000 BP. and 2 early H. sapiens sapiens mandibles both dating to circa 92.000 yr BP. Mandibular body length, the distance from the anterior border of the symphysis to a line bisecting the first molar (distance 1), and the distance from the line bisecting the first molar to the mandibular angle (distance 2) were measured. Distance 1, showed little variation between specimens. However, distance 2 showed a significant difference between sexes and between early and late specimens. For all specimens examined there was a low nonsignificant correlation, between the length of the mandible and distance 1, while there was a high correlation between the length of the mandibular body and distance 2. There was little or no correlation between distance 1 and 2. We propose that the human mandible, as a lever arm, can be divided into two functional parts; an anterior part which shows little change over the last 90000 years, and a posterior part which differs in accordance with the length of the mandibular corpus. These changes in distance 2 appear to correlate to changes in body size and diet, suggesting that as proposed by Hylander (1988) chewing rather than incision has played the main role in evolutionary trends of the hominid mandible. This is also in accordance with mandibular growth during development where the lengthening of the jaw takes place mostly in the posterior part by remodeling in the ramus area (Enlow, 1990) both during individual development (ontogenesis) and through evolutionary changes (phylogenesis).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02447644
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    The competition controversy in community ecology (1993)
    Springer
    Biology and philosophy 8 (1993), S. 359-384 
    Details
    ISSN: 1572-8404
    Keywords: Ecology ; evolution ; competition ; theory testing ; modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract There is a long history of controversy in ecology over the role of competition in determining patterns of distribution and abundance, and over the significance of the mathematical modeling of competitive interactions. This paper examines the controversy. Three kinds of considerations have been involved at one time or another during the history of this debate. There has been dispute about the kinds of regularities ecologists can expect to find, about the significance of evolutionary considerations for ecological inquiry, and about the empirical credentials of theoretical studies of competition. Each of these elements is examined with an eye toward gaining philosophical clarification of the issues involved. In the process, certain shortcomings of contemporary philosophical theories are revealed. In particular, I argue that plausibility arguments based on background considerations are an important part of the model building tradition, but that current accounts of the structure and evaluation of scientific theories do little to illuminate this side of theoretical ecology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00857684
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Chromosomal effects on peptidase activities inDrosophila melanogaster (1993)
    Springer
    Biochemical genetics 31 (1993), S. 29-50 
    Details
    ISSN: 1573-4927
    Keywords: Drosophila ; peptidase ; activity modifiers ; kinetic parameters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The peptidase system inDrosophila melanogaster (dipeptidase-A, -B, and -C and leucine aminopeptidases G and P) was used as a model to study the effects of modifier genes on activity of enzymes with similar functions. A screen of X, second, and third chromosome substitution isogenic lines revealed the presence of activity modifiers for peptidases on all three chromosomes. Correlation analyses indicated that covariation between some of the peptidase activities is independent of genetic background, while others are associated with variable second chromosomes. Chromosome-specific effects onK m ,V max, and specific activity of partially purified peptidases were also detected. Moreover, a repeatable technique using anion-exchange column chromatography allowed the characterization of possibly two putative peptidic enzymes, glycyl-l-isoleucine-ase andl-leucyl-l-proline-ase, whose kinetic properties differ from the dipeptidases and the leucine aminopeptidases. These findings confirm the existence of activity modifiers for peptidases, much like other enzymes inDrosophila melanogaster.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02399818
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    A correction for allele frequency estimates derived from isofemale lines (1993)
    Springer
    Biochemical genetics 31 (1993), S. 61-74 
    Details
    ISSN: 1573-4927
    Keywords: isofemale ; allele frequency estimation ; population structure ; allozyme ; microsatellites ; restriction fragment length polymorphisms ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Isofemale lines are commonly used inDrosophila and other genera for the purpose of assaying genetic variation. Isofemale lines can be kept in the laboratory for many generations before genetic work is carried out, and permit the confirmation of newly discovered alleles. A problem not realized by many workers is that the commonly used estimate of allele frequency from these lines is biased. This estimation bias occurs at all times after the first laboratory generation, regardless of whether single individuals or pooled samples are used in each well of an electrophoretic gel. This bias can potentially affect the estimation of population genetic parameters, and in the case of rare allele analysis it can cause gross overestimates of gene flow. This paper provides a correction for allele frequency estimates derived from isofemale lines for any time after the lines are established in the laboratory. When pooled samples are used, this estimator performs better than the standard estimator at all times after the first generation. The estimator is also insensitive to multiple inseminations. After the lines have drifted oneN e generations, multiple inseminations actually make the new estimator perform better than it does in singly inseminated females. Simulations show that estimates made using either estimator after the lines have drifted to fixation have a much greater error associated with their use than do those estimates made earlier in time using the correction. In general it is better to use corrected estimates of gene frequency soon after lines are established than to use uncorrected estimates made after the first laboratory generation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02399820
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Chromosomal effects on peptidase activities inDrosophila melanogaster (1993)
    Springer
    Biochemical genetics 31 (1993), S. 29-50 
    Details
    ISSN: 1573-4927
    Keywords: Drosophila ; peptidase ; activity modifiers ; kinetic parameters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The peptidase system inDrosophila melanogaster (dipeptidase-A, -B, and -C and leucine aminopeptidases G and P) was used as a model to study the effects of modifier genes on activity of enzymes with similar functions. A screen of X, second, and third chromosome substitution isogenic lines revealed the presence of activity modifiers for peptidases on all three chromosomes. Correlation analyses indicated that covariation between some of the peptidase activities is independent of genetic background, while others are associated with variable second chromosomes. Chromosome-specific effects onK m ,V max, and specific activity of partially purified peptidases were also detected. Moreover, a repeatable technique using anion-exchange column chromatography allowed the characterization of possibly two putative peptidic enzymes, glycyl-l-isoleucine-ase andl-leucyl-l-proline-ase, whose kinetic properties differ from the dipeptidases and the leucine aminopeptidases. These findings confirm the existence of activity modifiers for peptidases, much like other enzymes inDrosophila melanogaster.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553599
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Rapid evolution of host specificity in a parasitic nematode (1993)
    Springer
    Evolutionary ecology 7 (1993), S. 103-108 
    Details
    ISSN: 1573-8477
    Keywords: host-parasite interactions ; coevolution ; host specificity ; Drosophila ; Howardula
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In eastern North America, the nematodeHowardula aoronymphium parasitizes four species of mushroom-breedingDrosophila:D. falleni andD. recens of the quinaria species group, andD. putrida andD. testacea of the testacea group. One strain ofH. aoronymphium, designated Mendon-87, was initially capable of infecting all four of these host species. After less than 3 years in laboratory culture usingD. falleni as the sole host, this strain had completely lost the ability to infectD. putrida. Two other nematode strains parasitizedD. falleni andD. putrida at equal rates. These results demonstrate the existence of genetic variation for host specificity within this nematode species. More importantly, they show that host specificity can evolve rapidly when only one host is available for parasitization. Ecological conditions are such that natural populations ofH. aoronymphium may comprise numerous host races, lineages incapable of parasitizing the full range of host species. However, I argue that such host races are probably ephemeral and thus unlikely to persist long enough to undergo speciation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01237736
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Adenine phosphoribosyltransferase genes in two Drosophila species: dosage compensation, a nuclear matrix attachment site, and a novel intron position (1993)
    Springer
    Molecular genetics and genomics 238 (1993), S. 383-389 
    Details
    ISSN: 1617-4623
    Keywords: APRT ; Drosophila ; Nuclear matrix attachment site ; Dosage compensation ; Introns
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Aprt locus of Drosophila encodes the structural gene for the purine salvage enzyme adenine phosphoribosyltransferase. Aprt is autosomal and enzyme activity is gene-dose-dependent in Drosophila melanogaster. However, Aprt is X-linked and dosage compensated in Drosophila pseudoobscura, as shown here. The Aprt genes of both Drosophila species contain a DNA sequence associated with nuclear matrix attachment sites and these Aprt sequences specifically bind to nuclear matrix in vitro. Putative promoter sequences positioned upstream of the predicted transcriptional start site in the two Aprt genes have a similar structure of direct repeats with an overlapping dyad symmetry, but the DNA sequence of these motifs is not conserved between the two species. Biological features in mutants of Aprt as well as natural variants suggest that dosage compensation of this gene in Drosophila pseudoobscura is due to a general control Mechanism on X-linked genes rather than a gene-specific mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00291997
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Germ-line expression of the I factor, a functional LINE from the fruit fly Drosophila melanogaster, is positively regulated by reactivity, a peculiar cellular state (1993)
    Springer
    Molecular genetics and genomics 240 (1993), S. 277-285 
    Details
    ISSN: 1617-4623
    Keywords: I factor ; LINE ; Drosophila ; Hybrid dysgenesis ; Maternal inheritance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract I factor is a functional LINE (long interspersed nucleotidic element) which is mobilized in the germ-line of dysgenic SF females during I-R hybrid dysgenesis. Such females are obtained when an oocyte from a reactive stock, devoid of I factors but characterized by a level of reactivity, i.e. its potential for hybrid dysgenesis, is fertilized by a spermatozoon from an I factor-containing inducer stock. In a previous paper we described the expression of an I factor-lacZ fusion. Expression was detected in the ovaries of reactive and dysgenic flies only. In this paper we show that this transgenic activity can be quantified and depends upon the maternally inherited reactivity. Reactivity is not just a permissive state and modifiers of the reactivity level such as heat treatment and ageing change the level of expression of our transgenic fusion accordingly. Moreover, ageing through generations has the same cumulative and reversible effect on both reactivity and I factor expression. Using our fusion as a test for reactivity we show that the silencing of I factor after its introduction into a reactive genome may not be established in a single generation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00277067
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Cloning and molecular genetic analysis of Drosopbila melanogaster interband DNA (1993)
    Springer
    Molecular genetics and genomics 238 (1993), S. 437-443 
    Details
    ISSN: 1617-4623
    Keywords: Polytene chromosome ; Transformation ; Interband ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Interband DNA of Drosophila melanogaster polytene chromosomes was studied using a novel approach based on the electron microscopic (EM) analysis of chromosome regions carrying DNA fragements of known molecular genetic composition, inserted by P element-mediated transformation. Insertion of such fragments predominantly into interbands makes it possible to clone interband DNA by constructing genomic libraries from transformed strains and probing them with the insert DNA. The transformed strain P[H-sp70:Adh](61C) has insertion in the 61 C7-8 interband on the left arm of chromosome 3. This DNA consists of part of the hsp70 gene promoter fused to the coding region of the Adh gene, and is flanked on either side by P element sequences. We constructed a genomic library from DNA of this strain and isolated a clone containing the insert and the interband DNA. Subsequently the genomic library of wild-type strain was probed with a subclone composed of interband DNA only. We have thus isolated a clone containing the entire native interband. 1289 by of interband DNA was sequenced and found to be AT-rich (53.4%) with numerous regions of overlapping direct and inverted repeats, regulatory sites, and two overlapping open reading frames (ORFs).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292003
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    The vestigial locus of Drosophila melanogaster is involved in resistance to inhibitors of dTMP synthesis (1993)
    Springer
    Molecular genetics and genomics 241 (1993), S. 42-48 
    Details
    ISSN: 1617-4623
    Keywords: Vg mutant ; Antifolates ; Dihydrofolate reductase ; Drosophila ; Nucleotide metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The vestigal (vg) gene encodes a nuclear protein which plays a major role in the formation of the wing of Drosophila. Resistance or sensitivity to aminopterin, an inhibitor of the dihydrofolate reductase enzyme in D. melanogaster, seems to be associated with a specific alteration in vg gene function. Wild-type and vg mutant strains selected for growth on increasing concentrations of aminopterin display changes in physiological and biochemical parameters such as viability on normal and aminopterin-containing media, duration of development, wing phenotype, dihydrofolate reductase activity, and cross-resistance to fluorodeoxyuridine (FUdR) and to methotrexate. Our results indicate that the mechanisms of resistance differ in the wild-type and mutant strains. The vg 83b27 mutant, in which the major part of intron 2 of the vg gene is deleted, is associated with a high rate of resistance to FUdR, an inhibitor of thymidylate synthetase. Moreover, vg 83b27/vg BGheterozygotes, which are wild type when grown on normal medium, display a strong vg phenotype when grown on aminopterin. Our results indicate a role for the vestigial locus in mediating resistance to inhibitors of dTMP synthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00280199
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Theoretical assessment of alternative mechanisms for non-photochemical quenching of PS II fluorescence in barley leaves (1993)
    Springer
    Photosynthesis research 36 (1993), S. 119-139 
    Details
    ISSN: 1573-5079
    Keywords: energy dissipation ; photoinhibition ; photosynthesis ; Photosystem II ; quantum yield ; state transition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The components of non-photochemical chlorophyll fluorescence quenching (qN) in barley leaves have been quantified by a combination of relaxation kinetics analysis and 77 K fluorescence measurements (Walters RG and Horton P 1991). Analysis of the behaviour of chlorophyll fluorescence parameters and oxygen evolution at low light (when only state transitions — measured as qNt — are present) and at high light (when only photoinhibition — measured as qNi — is increasing) showed that the parameter qNt represents quenching processes located in the antenna and that qNi measures quenching processes located in the reaction centre but which operate significantly only when those centres are closed. The theoretical predictions of a variety of models describing possible mechanisms for high-energy-state quenching, measured as the residual quenching, qNe, were then tested against the experimental data for both fluorescence quenching and quantum yield of oxygen evolution. Only one model was found to agree with these data, one in which antennae exist in two states, efficient in either energy transfer or energy dissipation, and in which those photosynthetic units in a dissipative state are unable to exchange energy with non-dissipative units.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00016277
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Oxygen evolution by Photosystem II: The contribution of backward transitions to the anomalous behaviour of double-hits revealed by a new analysis method (1993)
    Springer
    Photosynthesis research 36 (1993), S. 111-118 
    Details
    ISSN: 1573-5079
    Keywords: Photosystem II ; S-states ; oxygen evolution ; probabilities ; flashing light
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Backward transitions in the analysis of oxygen production under flashing light were introduced by Packham et al., 1988, Photosynth. Res. 15: 221–232. In order to take backward transitions into account, a new method of analysis is presented: the ‘eigenvalue method’. This method is based on the recurrence relation of oxygen production with four coefficients (also known as the four ‘sigma’ coefficients). It shows less susceptibility to round-off errors than other methods and permits the computation of double-hits directly from the coefficients, which was not possible before. With it we discovered that the inconsistent behaviour of double-hits observed previously under low flash intensities or low flash frequencies was mainly due to the inclusion of the backward transitions into the double-hit probability. In these conditions backward transitions seemed to be due either to the combination of an S-state deactivation and a miss, or to two S-state deactivations and a single-hit. In the presence of 3-(3, 4-Dichlorophenyl)-1, 1-dimethylurea (DCMU), the previous methods of ‘sigma’ analysis failed. In contrast, the new method resolved all four S-state probabilities; thus it has the further advantage of being more ‘robust’ (robustness being defined as the ability to yield a meaningful answer under difficult conditions).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00016276
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    The degree of functional separation between the two photosystems in isolated thylakoid membranes deduced from inhibition studies of the imbalance in photoactivities (1993)
    Springer
    Photosynthesis research 36 (1993), S. 89-94 
    Details
    ISSN: 1573-5079
    Keywords: chlorophyll fluorescence ; Emerson enhancement ; Photosystem I ; Photosystem II ; lateral heterogeneity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to examine whether the two photosystems, PS I and PS II, are organized in specific electron transporting pairs, or randomly transport electrons from PS II to PS I, the photosystems imbalance of photoactivities (Emerson enhancement) was measured by modulated fluorimetry under different degrees of PS II inhibition in broken chloroplasts, where the granal structures were preserved by the presence of 5 mM MgCl. The results indicate a lack of any measurable specific functional pairing between individual PS I and PS II, in contrast to a previous research work in leaves (Malkin et al. 1986, Photosynth. Res. 10: 291–296). These results and this discrepancy are further discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00016273
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Redox control of gene expression and the function of chloroplast genomes — an hypothesis (1993)
    Springer
    Photosynthesis research 36 (1993), S. 95-102 
    Details
    ISSN: 1573-5079
    Keywords: chloroplast genome ; electron transport ; evolution ; gene expression ; redox response regulators ; redox sensors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two-component regulatory systems that respond to changes in redox potential have recently been discovered in bacteria. ‘Redox sensors’ are defined as electron carriers which initiate control of gene expression upon oxidation or reduction. ‘Redox response regulators’ are defined as DNA-binding proteins which modify gene expression as a result of the action of redox sensors. Redox sensors and redox response regulators may comprise a mechanism for feedback control of redox potential in photosynthetic electron transport chains, thereby protecting plants, algae and photosynthetic bacteria from damage caused by electrochemistry operating on inappropriate electron donors and acceptors. Chloroplast redox sensors and redox response regulators, themselves encoded in the nucleus, may place chloroplast gene expression under redox regulatory control. This may account for the persistence, in evolution, of chloroplast genomes, and for the constancy of the sub-set of chloroplast proteins encoded and synthesised in situ. These and other predictions are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00016274
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    IsProchlorothrix hollandica the best choice as a prokaryotic model for higher plant Chla/b photosynthesis? (1993)
    Springer
    Photosynthesis research 37 (1993), S. 61-68 
    Details
    ISSN: 1573-5079
    Keywords: chloroplast ; phylogeny ; prochlorophyte ; evolution ; Prochloron ; psbA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We examine the issue of prochlorophyte origins and provide analyses which highlight the limitations of inferring evolutionary trees from anciently diverged sequences that have markedly different GC contents. Under these conditions we have found that current tree reconstruction methods strongly group together sequences with similar GC contents, whether or not the sequences share a common ancestor. We provide 3′psbA termini sequence forProchloron didemni and find it does not have the 7 amino acid deletion that occurs in Chla/b chloroplasts andProchlorothrix hollandica. This is consistent with the recent findings of a Chlc like pigment in the light harvesting system in other prochlorophytes but apparently absent inP. hollandica. From these observations we suggest thatP. hollandica is the prochlorophyte most closely related to Chla/b containing chloroplasts and hence the most appropriate prokaryotic model for higher plant Chla/b photosynthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185439
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Kok's oxygen clock: What makes it tick? The structure of P680 and consequences of its oxidizing power (1993)
    Springer
    Photosynthesis research 38 (1993), S. 297-301 
    Details
    ISSN: 1573-5079
    Keywords: P680 ; Photosystem II ; reaction center
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract New insights in the structure of P680, the primary electron donor in Photosystem II, are summarized and the implications of its oxidizing power for energy transfer and singlet oxygen production are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046753
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    NMR paramagnetic relaxation enhancements due to manganese in the S0 and S2 states of Photosystem II-enriched membrane fragments and in the detergent-solubilized Photosystem II complex (1993)
    Springer
    Photosynthesis research 38 (1993), S. 347-354 
    Details
    ISSN: 1573-5079
    Keywords: NMR ; nuclear spin relaxation ; water oxidation ; oxygen evolution ; Photosystem II ; manganese oxidation state ; S-state
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The NMR paramagnetic relaxation enhancement (NMR-PRE) produced in the solvent proton resonance by manganese in the S0 and S2 states of the oxygen evolving center (OEC) has been recorded for three Photosystem II (PS II)-enriched preparations: (1) PS II-enriched thylakoid membrane fragments (TMF-2 particles); (2) salt-washed (2M NaCl) TMF-2 particles; and (3) the octylglucopyranoside (OGP)-solubilized PS II complex. The second and third preparations, but not the first, are depleted of the peripheral 17 and 23 kD polypeptides associated with the OEC. It has been proposed that depletion of these polypeptides increases the exposure of OEC manganese to the aqueous phase. The NMR-PRE response measures the quantity (T1m+τm)-1, where T1m is the spin relaxation time and τm is the mean residence time with respect to chemical exchange reactions of solvent protons in the manganese coordination sphere, and, thus, the NMR-PRE provides a direct measure of the solvent proton chemical exchange rate constant τm -1. This study tested whether the 17 and 23 kD polypeptides shield the OEC from the solvent phase and whether their depletion enhances the S2 and S0 NMR-PRE signals by removing a kinetic barrier to the solvent proton chemical exchange reaction. The amplitude of the S2 NMR-PRE signal, measured in its chemical exchange-limited regime (τm〉T1m), is slightly decreased, rather than increased, in preparations (2) and (3) relative to (1), indicating that removal of the 17 and 23 kD polypeptides slightly slows, rather than accelerates, the rate-limiting steps of the solvent proton chemical exchange reactions. In addition, the lifetime of the S2 state was shortened several-fold in the solubilized PS II complex and in salt-washed TMF-2 membranes relative to untreated TMF-2 control samples. The S0 NMR-PRE signal, which is present in TMF-2 suspensions, was not detected in suspensions of the solubilized PS II complex, even though these samples contained high concentrations of active manganese centers (approximately double those of the TMF-2 control) and exhibited an S2 NMR-PRE signal of comparable amplitude to that of the TMF-2 preparation. These results suggest that the 17 and 23 kD extrinsic polypeptides do not shield the NMR-visible water binding site in the OEC from the aqueous phase, although their removal substantially alters the proton relaxation efficiency by shortening T1m.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046760
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Thermoluminescence properties of the S2-state in chloride-depleted water oxidizing complexes after reconstituting treatments with various monovalent anions (1993)
    Springer
    Photosynthesis research 38 (1993), S. 395-400 
    Details
    ISSN: 1573-5079
    Keywords: anionic cofactors ; chloride effect ; oxygen evolution ; Photosystem II ; Spinacea oleracea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Under conditions that assured rebinding of the extrinsic 17 and 23 kDa polypeptides, Cl--depleted Photosystem II membranes isolated from spinach chloroplasts were subjected to reconstituting treatments in media containing NaF, NaCl, NaBr, NaI or NaNO3, or they were kept in a medium without any added salt other than the buffer. After removing most of the unbound reconstituting anions by washing, the O2-evolution activities and thermoluminescence properties of the membranes were compared. While the temperature of maximal thermoluminescence emission was lowest for membranes treated with Cl-, no uniform correlation was evident between the temperature profile of the thermoluminescence emission and the apparent activating effectiveness of the anions in the membranes' water oxidizing machinery. However, the differences between the thermoluminescence features did conform to a trend according to which the emission temperatures were upshifted as the size of the activating anion increased, and its hydration energy decreased, i.e. Cl-〈Br-〈NO3 -〈I-. The inactive F- anions were not well retained by the membranes. To explain the experimental data it is suggested that the structural environment of the charge accumulating Mn-center is influenced by the ionic conditions encountered by the Photosystem II membranes after Cl- removal, further enforced by the binding of compatible anions, and then stabilized by the 17 and 23 kDa extrinsic polypeptides. If, as some concepts imply, the anion binding sites are located at or near the functional Mn, only very exceptional characteristics of the water-oxidizing mechanism may account for the observation that the potentially electron-donating I- anion can serve as activator and that it stabilizes rather than destabilizes the S2-state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046766
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Can CO2 assimilation in maize leaves be predicted accurately from chlorophyll fluorescence analysis? (1993)
    Springer
    Photosynthesis research 37 (1993), S. 89-102 
    Details
    ISSN: 1573-5079
    Keywords: C4 photosynthesis ; chlorophyll fluorescence ; CO2 assimilation ; maize ; Photosystem II ; quantum yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Analysis is made of the energetics of CO2 fixation, the photochemical quantum requirement per CO2 fixed, and sinks for utilising reductive power in the C4 plant maize. CO2 assimilation is the primary sink for energy derived from photochemistry, whereas photorespiration and nitrogen assimilation are relatively small sinks, particularly in developed leaves. Measurement of O2 exchange by mass spectrometry and CO2 exchange by infrared gas analysis under varying levels of CO2 indicate that there is a very close relationship between the true rate of O2 evolution from PS II and the net rate of CO2 fixation. Consideration is given to measurements of the quantum yields of PS II (φ PS II) from fluorescence analysis and of CO2 assimilation ( $$\phi _{CO_2 } $$ ) in maize over a wide range of conditions. The $${{\phi _{PSII} } \mathord{\left/ {\vphantom {{\phi _{PSII} } {\phi _{CO_2 } }}} \right. \kern-\nulldelimiterspace} {\phi _{CO_2 } }}$$ ratio was found to remain reasonably constant (ca. 12) over a range of physiological conditions in developed leaves, with varying temperature, CO2 concentrations, light intensities (from 5% to 100% of full sunlight), and following photoinhibition under high light and low temperature. A simple model for predicting CO2 assimilation from fluorescence parameters is presented and evaluated. It is concluded that under a wide range of conditions fluorescence parameters can be used to predict accurately and rapidly CO2 assimilation rates in maize.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02187468
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    The role of calcium in the pH-dependent control of Photosystem II (1993)
    Springer
    Photosynthesis research 37 (1993), S. 117-130 
    Details
    ISSN: 1573-5079
    Keywords: Photosystem II ; calcium ; oxygen evolution ; primary quinone acceptor ; redox potential ; fluorescence quenching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract pH-dependent inactivation of Photosystem (PS) II and related quenching of chlorophyll-a-fluorescence have been investigated in isolated thylakoids and PS II-particles and related to calcium release at the donor side of PS II. The capacity of oxygen evolution (measured under light saturation) decreases when the ΔpH is high and the pH in the thylakoid lumen decreases below 5.5. Oxygen evolution recovers upon uncoupling. The pH-response of inactivation can be described by a 1 H+-transition with an apparent pK-value of about 4.7. The yield of variable fluorescence decreases in parallel to the inactivation of oxygen evolution. pH-dependent quenching requires light and can be inhibited by DCMU. In PS II-particles, inactivation is accompanied by a reversible release of Ca2+-ions (one Ca2+ released per 200 Chl). In isolated thylakoids, where a ΔpH was created by ATP-hydrolysis, both inactivation of oxygen evolution (and related fluorescence quenching) by internal acidification and the recovery of that inactivation can be suppressed by calcium-channel blockers. In the presence of the Ca2+-ionophore A23187, recovery of Chl-fluorescence (after relaxation of the ΔpH) is stimulated by external Ca2+ and retarded by EGTA. As shown previously (Krieger and Weis 1993), inactivation of oxygen evolution at low pH is accompanied by an upward shift of the midpoint redox-potential, Em, of QA. Here, we show that in isolated PS II particles the pH-dependent redox-shift (about 160 mV, as measured from redox titration of Chl-fluorescence) is suppressed by Ca2+-channel blockers and DCMU. When a redox potential of −80 to −120mV was established in a suspension of isolated thylakoids, the primary quinone acceptor, QA, was largely reduced in presence of a ΔpH (created by ATP-hydrolysis) but oxidized in presence of an uncoupler. Ca2+-binding at the lumen side seems to control redox processes at the lumen- and stroma-side of PS II. We discuss Ca2+-release to be involved in the physiological process of ‘high energy quenching’.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02187470
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Perspectives on the structure of the photosynthetic oxygen evolving manganese complex and its relation to the Kok cycle (1993)
    Springer
    Photosynthesis research 38 (1993), S. 265-277 
    Details
    ISSN: 1573-5079
    Keywords: Photosystem II ; oxygen evolution ; manganese
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This review describes the progress in our understanding of the structure of the Mn complex in Photosystem II over the last two decades. Emphasis is on the research from our laboratory, especially the results from X-ray absorption spectroscopy, low temperature electron paramagnetic resonance and electron spin echo envelope modulation studies. The importance of the interplay between electron paramagnetic resonance studies and X-ray absorption studies, which has led to a description of the oxidation states of manganese as the enzyme cycles through the Kok cycle, is described. Finally, the path, by which our group has utilized these two important methods to arrive at a working structural model for the manganese complex that catalyzes the oxidation of water to dioxygen in higher plants and cyanobacteria, is explained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046751
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    High misses after odd flashes in oxygen evolution in thoroughly dark-adapted thylakoids from pea and Chenopodium album (1993)
    Springer
    Photosynthesis research 38 (1993), S. 309-314 
    Details
    ISSN: 1573-5079
    Keywords: chloroplasts ; oxygen evolving complex ; Photosystem II ; quinone acceptors ; S-states
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In Photosystem II (PS II), water is oxidized to molecular oxygen and plastoquinone is reduced to plastoquinol. The oxidation of water requires the accumulation of four oxidizing equivalents, through the so-called S-states of the oxygen evolving complex; the production of plastoquinol requires the accumulation of two reducing equivalents on a bound plastoquinone, QB. It has been generally believed that during the flash-induced transition of each of the S-states (Sn → Sn+1, where n=0, 1, 2 and 3), a certain small but equal fraction of the PS II reaction centers are unable to function and, thus, ‘miss’ being turned over. We used thoroughly dark-adapted thylakoids from peas (Pisum sativum) and Chenopodium album (susceptible and resistant to atrazine) starting with 100% of the oxygen evolving complex in the S1 state. Thylakoids were illuminated with saturating flashes, providing a double hit parameter of about 0.07. Our experimental data on flashnumber dependent oscillations in the amount of oxygen per flash fit very well with a binary pattern of misses: 0, 0.2, 0, 0.4 during S0 → S1, S1 → S2, S2 → S3 and S3 → S0 transitions. Addition of 2 mM ferricyanide appears to shift this pattern by one flash. These results are consistent with the ‘bicycle’ model recently proposed by V. P. Shinkarev and C. A. Wraight (Oxygen evolution in photosynthesis: From unicycle to bicycle, 1993, Proc Natl Acad Sci USA 90: 1834–1838), where misses are due to the presence of P+ or QA - among the various equilibrium states of PS II centers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046755
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Kinetic factors in the bicycle model of oxygen evolution by Photosystem II (1993)
    Springer
    Photosynthesis research 38 (1993), S. 315-321 
    Details
    ISSN: 1573-5079
    Keywords: Photosystem II ; oxygen evolution ; S-states ; quinones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Flash-induced oxygen evolution and many related processes in thylakoids of oxygenic organisms are modulated with period four by the S-state transitions associated with the oxygen evolving system of Photosystem II (PS II). To analyze these phenomena, we have interpreted the S-state model on the basis of the charge accumulating activities on both sides of PS II-4 charges on the donor side and 2 charges on the acceptor side. This results in the recognition of two parallel reaction center cycles V and W of PS II function (V.P. Shinkarev and C.A. Wraight (1993) Proc Natl Acad Sci USA 90: 1834–1838). The description of damping of the period four oscillations is here extended to include kinetic sources of misses in both cycles. Such misses arise in reaction centers (RCs) in which back reaction between P+ and QA - occurs before the electron transfer equilibria on the donor and acceptor sides of the RC are reached. These are in addition to misses which are determined by reaction centers (RCs) that are inactive at the time of the flash due to the presence of either P+ or QA - according to the electron transfer equilibria on the donor and acceptor sides of the RC. Using known or estimated values of the equilibrium and rate constants for donor and acceptor side reactions of the RC, this provides a natural and quantitatively reasonable description of the flash number dependence of oxygen evolution and other period four modulated processes of PS II. The estimated miss factors are different for both cycles V and W and are dependent on flash number and pH. Estimates based on existing data show that miss factors of the first type (kinetic) are dominant at low pH, while those of the second type (equilibrium) are dominant at high pH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046756
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Analytical procedures for the quantification of isotopic amino acid incorporation into photosynthetic proteins of Synechocystis PCC 6803 (1993)
    Springer
    Photosynthesis research 38 (1993), S. 379-386 
    Details
    ISSN: 1573-5079
    Keywords: auxotroph ; mass spectrometry ; Photosystem II ; tyrosine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mechanism of oxygen evolution has been an enigma for nearly two centuries. Pioneering work by Bessel Kok, Pierre Joliot, and many others during the last quarter century has provided valuable insight into this most unique and important chemical reaction. The late 1970s and early 1980s saw the introduction of biochemical techniques for the purification of photosynthetic complexes that have, in turn, stimulated the biophysical chemists and spectroscopists to apply high resolution techniques in order to resolve the structure/function relationships in these protein complexes. Valuable information about events at the atomic level can be gained through isotopic substitution of particular amino acids thought to be important in the catalytic process. The ability to generate functional auxotrophs in the photosynthetic cyanobacterium Synechocystis 6803 has been used successfully to identify the redox active components Z and D as tyrosine residues in the reaction center of Photosystem II. In this report, we present results of the application of specific isotopic labeling for high resolution spectroscopy of purified PS II particles. We have developed analytical procedures for monitoring the incorporation of both 2H and 17O labeled amino acids by gas chromatography-mass spectroscopic analysis. We also show that the growth curve of cells subjected to obligate auxotrophy displays two distinct stationary phases; one that corresponds to depletion of exogenous amino acids, and a second that corresponds to the normal cell density at stationary phase. Cells harvested at the second stationary phase show little or no retention of the labeled amino acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046764
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Increases in peroxide formation by the Photosystem II oxygen evolving reactions upon removal of the extrinsic 16, 22 and 33 kDa proteins are reversed by CaCl2 addition (1993)
    Springer
    Photosynthesis research 38 (1993), S. 417-423 
    Details
    ISSN: 1573-5079
    Keywords: calcium effects ; extrinsic proteins ; O2 evolution ; peroxide formation ; Photosystem II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This communication introduces a new spectrophotometric assay for the detection of peroxide generated by Photosystem II (PS II) under steady state illumination in the presence of an electron acceptor. The assay is based on the formation of an indamine dye in a horseradish peroxidase coupled reaction between 3-(dimethylamino)benzoic acid and 3-methyl-2-benzothiazolinone hydrazone. Using this assay, we found that as the O2 evolution activity of PS II-enriched membrane fragments is decreased by treatments which cause the dissociation of the 33 and/or 23 and 16 kDa extrinsic proteins (i.e., CaCl2-washing, NaCl-washing, lauroylcholine-treatment and ethylene glycol-treatment), light-induced peroxide formation increases. Both the losses of O2 evolution and increases in peroxide formation seen under these conditions are reversed by CaCl2 addition, indicating that the two activities originate from the water-splitting site. However, the increased rates of peroxide formation do not quantitatively match the losses in O2 evolution activity. We suggest that a rapid consumption of the peroxide takes place via a catalase/peroxidase activity at the water-splitting site which competes with both the O2 evolution and peroxide formation reactions. The observed peroxide formation is interpreted as arising from enhanced water accessibility to the catalytic site upon perturbation of the extrinsic proteins which then leads to alternate water oxidation side reactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046769
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Events near the reaction center in O2 evolving PS II enriched thylakoid membranes: The presence of an electric field during the S2 state in a population of centers (1993)
    Springer
    Photosynthesis research 37 (1993), S. 205-215 
    Details
    ISSN: 1573-5079
    Keywords: chlorophyll fluorescence ; electrochromic changes ; heterogeneity ; oxygen-evolving complex ; Photosystem II ; S states
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Flash-induced absorption changes at 515 nm observed as a function of flash number are examined in relation to the flash-induced fluorescence yields in inside-out thylakoids. After partial dissipation of the delocalized transmembrane electric field by adding gramicidin, the analysis of period 4 oscillations and of the kinetics in the 10 ms–1 s range suggest that the variation of the absorption changes at 515 nm as a function of flash number is the result of at least two processes:1) an electric field increase related to the S2 state and 2) the fact that the field generated by the water protons inside the membrane decreases when these protons are released outside the membrane. The former field correlates with the flash-induced fluorescence yield increase induced by the donor side of Photosystem II. Both measurements show similar oscillations as a function of flash number, with maxima on the 1st, 5th and 9th flash. These oscillations, after a shift of two flashes, appear to be different from those of the O2 yield observed under similar conditions. It is proposed that, in a population of centers the electric field during the S2 state reflects the presence of a stabilized positive equivalent in the protein close to the Mn complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00032824
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Evaluation of the role of State transitions in determining the efficiency of light utilisation for CO2 assimilation in leaves (1993)
    Springer
    Photosynthesis research 38 (1993), S. 15-26 
    Details
    ISSN: 1573-5079
    Keywords: CO2 assimilation ; light harvesting chlorophyll a/b protein complex ; Photosystem I ; Photosystem II ; protein phosphorylation ; quantum yield ; State transition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wheat leaves were exposed to light treatments that excite preferentially Photosystem I (PS I) or Photosystem II (PS II) and induce State 1 or State 2, respectively. Simultaneous measurements of CO2 assimilation, chlorophyll fluorescence and absorbance at 820 nm were used to estimate the quantum efficiencies of CO2 assimilation and PS II and PS I photochemistry during State transitions. State transitions were found to be associated with changes in the efficiency with which an absorbed photon is transferred to an open PS II reaction centre, but did not correlate with changes in the quantum efficiencies of PS II photochemistry or CO2 assimilation. Studies of the phosphorylation status of the light harvesting chlorophyll protein complex associated with PS II (LHC II) in wheat leaves and using chlorina mutants of barley which are deficient in this complex demonstrate that the changes in the effective antennae size of Photosystem II occurring during State transitions require LHC II and correlate with the phosphorylation status of LHC II. However, such correlations were not found in maize leaves. It is concluded that State transitions in C3 leaves are associated with phosphorylation-induced modifications of the PS II antennae, but these changes do not serve to optimise the use of light absorbed by the leaf for CO2 assimilation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00015057
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Polyamines in the photosynthetic apparatus (1993)
    Springer
    Photosynthesis research 38 (1993), S. 83-88 
    Details
    ISSN: 1573-5079
    Keywords: polyamines ; thylakoids ; Photosystem II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The three main polyamines putrescine (Put), spermidine (Spd) and spermine (Spm) were characterized by HPLC in intact spinach leaf cells, intact chloroplasts, thylakoid membranes, Photosystem II membranes, the light-harvesting complex and the PS II complex. All contain the three polyamines in various ratios; the HPLC polyamine profiles of highly resolved PS II species (a Photosystem II core and the rection center) suggest an enrichment in the polyamine Spm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00015064
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Flash-induced redox changes in oxygen-evolving spinach Photosystem II core particles (1993)
    Springer
    Photosynthesis research 38 (1993), S. 169-176 
    Details
    ISSN: 1573-5079
    Keywords: Photosystem II ; PS II core ; oxygen-evolving complex ; UV asorbance changes ; EPR signal II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Flash-induced redox reactions in spinach PS II core particles were investigated with absorbance difference spectroscopy in the UV-region and EPR spectroscopy. In the absence of artificial electron acceptors, electron transport was limited to a single turnover. Addition of the electron acceptors DCBQ and ferricyanide restored the characteristic period-four oscillation in the UV absorbance associated with the S-state cycle, but not the period-two oscillation indicative of the alternating appearance and disappearance of a semiquinone at the QB-site. In contrast to PS II membranes, all active centers were in state S1 after dark adaptation. The absorbance increase associated with the S-state transitions on the first two flashes, attributed to the Z+S1→ZS2 and Z+S2→ZS3 transitions, respectively, had half-times of 95 and 380 μs, similar to those reported for PS II membrane fragments. The decrease due to the Z+S3→ZS0 transition on the third flash had a half-time of 4.5 ms, as in salt-washed PS II membrane fragments. On the fourth flash a small, unresolved, increase of less than 3 μs was observed, which might be due to the Z+S0→ZS1 transition. The deactivation of the higher S-states was unusually fast and occurred within a few seconds and so was the oxidation of S0 to S1 in the dark, which had a half-time of 2–3 min. The same lifetime was found for tyrosine D+, which appeared to be formed within milliseconds after the first flash in about 10% inactive centers and after the third and later flashes by active centers in Z+S3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00146416
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Proton release during the redox cycle of the water oxidase (1993)
    Springer
    Photosynthesis research 38 (1993), S. 279-296 
    Details
    ISSN: 1573-5079
    Keywords: electrochromic changes ; oxygen-evolving complex ; Photosystem II ; proton release ; protolytic reactions ; Tyrosine Z
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Old and very recent experiments on the extent and the rate of proton release during the four reaction steps of photosynthetic water oxidation are reviewed. Proton release is discussed in terms of three main sources, namely the chemical production upon electron abstraction from water, protolytic reactions of Mn-ligands (e.g. oxo-bridges), and electrostatic response of neighboring amino acids. The extent of proton release differs between the four oxidation steps and greatly varies as a function of pH both, but differently, in thylakoids and PS II-membranes. Contrastingly, it is about constant in PS II-core particles. In any preparation, and on most if not all reaction steps, a large portion of proton transfer can occur very rapidly (〈20 μs) and before the oxidation of the Mn-cluster by Yz + is completed. By these electrostatically driven reactions the catalytic center accumulates bases. An additional slow phase is observed during the oxygen evolving step, S3⇒S4→S0. Depending on pH, this phase consists of a release or an uptake of protons which accounts for the balance between the number of preformed bases and the four chemically produced protons. These data are compatible with the hypothesis of concerted electron/proton-transfer to overcome the kinetic and energetic constraints of water oxidation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046752
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    A recollection of the development of the Kok-Joliot model for photosynthetic oxygen evolution (1993)
    Springer
    Photosynthesis research 38 (1993), S. 225-227 
    Details
    ISSN: 1573-5079
    Keywords: Bessel Kok ; Kok-Joliot model ; oxygen evolution ; Photosystem II ; Pierre Joliot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Twenty-five years of period-four O2-flash yield oscillation are celebrated with a personal recollection of the development of the Kok-Joliot model for photosynthetic oxygen evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046748
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Water cleavage by solar radiation—an inspiring challenge of photosynthesis research (1993)
    Springer
    Photosynthesis research 38 (1993), S. 229-247 
    Details
    ISSN: 1573-5079
    Keywords: absorption spectroscopy ; ENDOR ; EPR ; EXAFS ; manganese ; P680 ; Photosystem II ; S-states ; water oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Solar energy exploitation by photosynthetic water cleavage is of central relevance for the development and sustenance of all higher forms of living matter in the biosphere. The key steps of this process take place within an integral protein complex referred to as Photosystem II (PS II) which is anisotropically incorporated into the thylakoid membrane. This minireview concentrates on mechanistic questions related to i) the generation of strongly oxidizing equivalents (holes) at a special chlorophyll a complex (designated as P680) and ii) the cooperative reaction of four holes with two water molecules at a manganese containing unit WOC (water oxidizing complex) resulting in the release of molecular oxygen and four protons. The classical work of Pierre Joliot and Bessel Kok and their coworkers revealed that water oxidation occurs via a sequence of univalent oxidation steps including intermediary redox states Si (i = number of accumulated holes within the WOC). Based on our current stage of knowledge, an attempt is made a) to identify the nature of the redox states Si, b) to describe the structural arrangement of the (four) manganese centers and their presumed coordination and ligation within the protein matrix, and c) to propose a mechanism of photosynthetic water oxidation with special emphasis on the key step, i.e. oxygen-oxygen bond formation. It is assumed that there exists a dynamic equilibrium in S3 with one state attaining the nuclear geometry and electronic configuration of a complexed peroxide. This state is postulated to undergo direct oxidation to complexed dioxygen by univalent electron abstraction with YZ ox and simultaneous internal ligand to metal charge transfer. Key questions on the mechanism will be raised. The still fragmentary answers to these questions not only reflect our limited knowledge but also illustrate the challenges for future research.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046749
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Characterization of the psbK locus of Synechocystis sp. PCC 6803 in terms of Photosystem II function (1993)
    Springer
    Photosynthesis research 38 (1993), S. 369-377 
    Details
    ISSN: 1573-5079
    Keywords: molecular biology ; Photosystem II ; psbK gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The psbK gene encodes a small protein of Photosystem II. The gene has previously been cloned and sequenced in Synechocystis sp. PCC 6803. Our new results, presented here, confirm the conclusions of Ikeuchi et al. Based on Northern hybridization and primer extension analyses, we show that psbK is transcribed as a monocistronic message in this cyanobacterium. Analysis of DNA sequence immediately upstream of the transcription start site revealed an E. coli-like-10 consensus sequence. A deletion mutant was constructed where the psbK gene was replaced by a kanamycin resistant cartridge. In situ complementation experiments, as well as Southern and Northern hybridization analyses, confirmed that the mutant strain contains a lesion in psbK. The psbK-less mutant could grow photoautotrophically as well as photoheterotrophically both in liquid culture and on agar plates. The rate of growth was slightly less compared with the wild-type as clearly observed by in situ complementation experiments. Although the mutant showed correspondingly lower rates of electron transport, thermoluminescence, oxygen flash yield and chlorophyll a fluorescence measurements did not detect any significant modification of the reactions of PS II. Moreover, the mutant was no more susceptible to excess light than the wild-type. It is, therefore, concluded that the product of the psbK gene is not crucial for PS II activity and possibly plays some other role in the metabolism of Synechocystis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046763
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Functional characterisation of a purified homogeneous Photosystem II core complex with high oxygen evolution capacity from spinach (1993)
    Springer
    Photosynthesis research 35 (1993), S. 41-53 
    Details
    ISSN: 1573-5079
    Keywords: Photosystem II ; PS II core complexes ; thermoluminescence ; oxygen yield ; fluorescence quantum yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The functional properties of a purified homogeneous spinach PS II-core complex with high oxygen evolution capacity (Haag et al. 1990a) were investigated in detail by measuring thermoluminescence and oscillation patterns of flash induced oxygen evolution and fluorescence quantum yield changes. The following results were obtained: a) Depending on the illumination conditions the PS II-core complexes exhibit several thermoluminescence bands corresponding to the A band, Q band and Zv band in PS II membrane fragments. The lifetime of the Q band (Tmax=10°C) was determined to be 8s at T=10°C. No B band corresponding to S2QB − or S3QB − recombination could be detected. b) The flash induced transient fluorescence quantum yield changes exhibit a multiphasi relaxation kinetics shich reflect the reoxidation of Q A − . In control samples without exogenous acceptors this process is markedly slower than in PS II membrane fragments. The reaction becomes significantly retarded by addition of 10 μM DCMU. After dark incubation in the presence of K3[Fe(CN)6 c) Excitation of dark-adapted samples with a train of short saturating flashes gives rise to a typical pattern dominated by a high O2 yield due to the third flash and a highly damped period four oscillation. The decay of redox states S2 and S3 are dominated by short life times of 4.3 s and 1.5 s, respectively, at 20°C. The results of the present study reveal that in purified homogeneous PS II-core complexes with high oxygen evolution isolated from higher plants by β-dodecylmaltoside solubilization the thermodynamic properties and the kinetic parameters of the redox groups leading to electron transfer from water to QA are well preserved. The most obvious phenomenon is a severe modification of the QB binding site. The implications of this finding are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185410
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Can charge recombination as caused by pH-dependent donor-side limitation in PS 2 account for high-energy-state quenching? (1993)
    Springer
    Photosynthesis research 35 (1993), S. 97-100 
    Details
    ISSN: 1573-5079
    Keywords: chlorophyll fluorescence ; excitons ; Photosystem II ; triplet states
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Schreiber and Neubauer (Photosynthesis Research 25: 279–293, 1990) have proposed a model which explains energy quenching by enhanced triplet formation as caused by charge recombination due to pH-dependent donor-side limitation. Quenching under these conditions is assumed to result from two mechanisms. Firstly, there is the withdrawal of excited states by charge recombination and formation of triplet states. Secondly, these triplet states can result in carotenoid triplets in the antenna which are supposed to quench excitons. Here, it is shown that quenching caused by both mechanisms can account for only about 25% of the experimentally observed energy quenching even under extremely favorable conditions. More likely, this number is less than 15%, as the contribution of the second step in the proposed triplet cycle is expected to be low as the life times of the carotenoid triplets are not long enough to cause the assumed quenching of excitons in the antenna.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185415
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Cloning and sequencing of mutantpsbB genes of the cyanobacteriumSynechocystis PCC 6803 (1993)
    Springer
    Photosynthesis research 37 (1993), S. 139-146 
    Details
    ISSN: 1573-5079
    Keywords: chlorophyll-binding protein CP47 ; DNA sequence ; gene analysis ; mutagenesis ; Photosystem II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ten strains from a collection of mutants ofSynechocystis 6803 defective in Photosystem II (PS II) function were transformed with chromosomal DNA of wild-type and mutant cells. Cross hybridization data allowed to identify four groups of PS II-mutants. Highly efficient transformation was observed between different mutant groups, but not within the groups. Restoration of photosynthetic activity of the mutant cells was also achieved by transformation with different parts of a 5.6 kbBam HI fragment of wild typeSynechocystis DNA containing thepsbB gene. Each group of mutants was transformed to photoautotrophic growth by specific subfragments of thepsbB gene. DNA fragments of four selected mutant strains hybridizing with thepsbB gene were isolated and sequenced. The mutations were identified as a single nucleotide insertion or substitution leading to stop codon formation in two of the mutants, as a deletion of 12 nucleotides, or as a nucleotide substitution resulting in an amino acid substitution in the other two mutants. Deletion of 12 nucleotides in mutant strain PMB1 and stop codon formation in strain NF16 affect membrane-spanning regions of the gene product, the CP 47 protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02187472
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Manganese K-edge X-ray absorption spectra of the cyclic S-states in the photosynthetic oxygen-evolving system (1993)
    Springer
    Photosynthesis research 38 (1993), S. 331-339 
    Details
    ISSN: 1573-5079
    Keywords: manganese cluster ; oxygen evolution ; Photosystem II ; water oxidation ; XANES
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A set of Mn K-edge XANES spectra due to the redox states S0−S3 of the OEC were determined by constructing a highly-sensitive X-ray detection system for use with physiologically native PS II membranes capable of cycling under a series of saturating laser-flashes. The spectra showed almost parallel upshifts with relatively high K-edge half-height energies given by 6550.9±0.2 eV, 6551.7±0.2 eV, 6552.5±0.2 eV and 6553.6±0.2 eV for the S0, S1, S2 and S3 states, respectively. The successive difference spectra between S0 and S1, S1 and S2, and S2 and S3 states were found to exhibit a similar peak around 6552–6553 eV, indicating that one Mn(III) ion or its direct ligand is univalently oxidized upon each individual S-state transition from S0 to S3. The present data, together with other observations of EPR and pre-edge XANES spectroscopy, suggest that the oxidation state of the Mn cluster undergoes a periodic change; S0: Mn(III,III,III,IV) → S1: Mn(III,IV,III,IV) → S2: Mn(III,IV,IV,IV) → S3: Mn(IV,IV,IV,IV) or Mn(III,IV,IV,IV)·L+ with L being a direct ligand of a Mn(III) ion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046758
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Evidence for the contribution of the S-state transitions of oxygen evolution to the initial phase of fluorescence induction (1993)
    Springer
    Photosynthesis research 36 (1993), S. 81-88 
    Details
    ISSN: 1573-5079
    Keywords: chlorophyll fluorescence ; fluorescence induction ; Photosystem II ; S-state
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fluorescence induction of isolated spinach chloroplasts was measured by using weak continuous light. It is found that the kinetics of the initial phase of fluorescence induction as well as the initial fluorescence level Fj are influenced by the number of preilluminating flashes, and shows damped period 4 oscillation. Evidence is given to show that it is correlated with the S-state transitions of oxygen evolution. Based on the previous observations that the S states can modulate the fluorescence yield of Photosystem II, a simulating calculation suggests that, in addition to the Photosystem II centers inactive in the plastoquinone reduction, the S-state transitions can also make a contribution to the intial phase of fluorescence induction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00016272
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Hierarchal gene trees and molecular phylogeny of the Rotifera: use of the Polymerase Chain Reaction (PCR) to dissect ecological and evolutionary patterns (1993)
    Springer
    Hydrobiologia 255-256 (1993), S. 551-555 
    Details
    ISSN: 1573-5117
    Keywords: Rotifera ; Polymerase Chain Reaction ; PCR ; Molecular Phylogeny ; systematics ; evolution ; ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The study of rotifer phylogenies and the analysis of population-level processes historically have been disjunct. This is despite a growing recognition that there are many ways in which rotifer population biologists and ecologists might profit from the availability of a comprehensive phylogeny of the group. New molecular methods which can be applied to a wide range of genetic systems and systematic grades will shortly eliminate the methodological (and perhaps conceptual) distinction between these fields. Of particular importance is the development of the Polymerase Chain Reaction (PCR), a technique of synthetic DNA amplification which produces concentrated preparations of selected genes from complex mixtures of nuclear and mitochondrial genomes. Analysis of PCR products can provide hierarchal genetic comparisons from the level of local rotifer populations through broad evolutionary (at least molecular) phylogenies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00025884
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Patterns of sexual reproduction in diatoms (1993)
    Springer
    Hydrobiologia 269-270 (1993), S. 11-20 
    Details
    ISSN: 1573-5117
    Keywords: auxosporulation ; evolution ; sexual reproduction ; taxonomic character
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sexual reproduction takes many forms within the diatoms. The variation has been classified by several authors, but in most cases the distinctions between their main categories have depended on the number of gametes produced per gametangium (and thus on how many zygotes per pair of copulating cells), and upon whether fusion is oogamous, anisogamous or isogamous. These classifications are not themselves an adequate basis for taxonomic comparison, which should be based on individual characteristics of the sexual process. Diatoms seem to be primitively oogamous. In araphid pennate diatoms and some raphid diatoms the gametes and gametangia are morphologically alike but physiologically distinct; one gametangium produces active gametes and the other passive ones. This may be the primitive condition in pennate diatoms, providing a link to the oogamy of centrics via the morphological anisogamy of Rhabdonema Kütz.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027999
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Isozyme studies of genetic diversity and evolution in Hippophae (1993)
    Springer
    Genetic resources and crop evolution 40 (1993), S. 153-164 
    Details
    ISSN: 1573-5109
    Keywords: Hippophae ; isozyme ; genetic markers ; diversity ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary To provide information on the genetic variation, differentiation and evolution in Hippophae seed samples of 25 populations from China, Finland and Russia were electrophoretically analyzed. Of six loci investigated, four were good genetic markers for identifying species and subspecies. The percentages of polymorphic loci per population were 40.3% and 62.5% at 0.95 and 0.99 polymorphic criteria respectively. The mean number of alleles per locus per population was 2.1. Total genetic diversity in the material was 0.4614. Genetic diversity partitioning showed that there was a large amount of diversity residing within geographical populations (0.1354), between subspecies within species (0.1046) and between species (0.2566) but not between geographical populations (0.0114). There were nearly twice as many negative fixation indices as positive ones in Hippophae populations. The phylogenetic tree agreed very well with botanic classifications of the species and subspecies and their geographical distributions, and quantitatively presented the genetic relationships of 25 populations. A detailed view of the evolutionary stages in Hippophae showed clearly a general decline of similarity as evolutionary divergence continued, which further explained the evolution process in Hippophae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00051120
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...