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
  • Immunocytochemistry  (856)
  • Drosophila  (737)
  • Springer  (1,593)
  • Blackwell Publishing Ltd
  • American Institute of Physics (AIP)
Collection
Keywords
Publisher
Years
  • 1
    Electronic Resource
    Electronic Resource
    Analysis of a swallow homologue from Drosophila pseudoobscura (2000)
    Springer
    Development genes and evolution 210 (2000), S. 157-161 
    Details
    ISSN: 1432-041X
    Keywords: Key words Swallow ; bicoid ; Drosophila ; mRNA localization ; Oogenesis ; Embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We analyzed a functional homologue of the swallow gene from Drosophila pseudoobscura. The swallow gene of D. melanogaster plays an essential role in localizing bicoid mRNA in oocytes, and swallow mutant embryos show anterior pattern defects that result from the lack of localization of the bicoid morphogen. The pseudoobscura homologue rescues the function of swallow mutants when introduced into the genome of D. melanogaster, and its expression is similar to that of the melanogaster gene. The predicted pseudoobscura and melanogaster proteins are 49% identical and 69% conserved. The coiled-coil domain previously identified in the melanogaster swallow protein is strongly conserved in the pseudoobscura homologue, but the weak similarity of the melanogaster swallow protein to the RNP class of RNA-binding proteins is not conserved in the pseudoobscura homologue. These and other observations suggest a structural role for swallow in localizing bicoid mRNA, perhaps as part of the egg cytoskeleton.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050023
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Changes in cell shape in the ventral neuroectoderm of Drosophila melanogaster depend on the activity of the achaete-scute complex genes (2000)
    Springer
    Development genes and evolution 210 (2000), S. 190-199 
    Details
    ISSN: 1432-041X
    Keywords: Key words Ventral neuroectoderm ; Cell shape ; Achaete-scute complex ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  In the embryonic ventral neuroectoderm of Drosophila melanogaster the proneural genes achaete, scute, and lethal of scute are expressed in clusters of cells from which the neuroblasts delaminate in a stereotyped orthogonal array. Analyses of the ventral neuroectoderm before and during delamination of the first two populations of neuroblasts show that cells in all regions of proneural gene activity change their form prior to delamination. Furthermore, the form changes in the neuroectodermal cells of embryos lacking the achaete-scute complex, of embryos mutant for the neurogenic gene Delta, and of embryos overexpressing l’sc suggest that these genes are responsible for most of the morphological alterations observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050303
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Patterning defects in the primary axonal scaffolds caused by the mutations of the extradenticle and homothorax genes in the embryonic Drosophila brain (2000)
    Springer
    Development genes and evolution 210 (2000), S. 289-299 
    Details
    ISSN: 1432-041X
    Keywords: Key words Brain development ; Axonal scaffold ; Extradenticle ; Homothorax ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  During early brain development in Drosophila a highly stereotyped pattern of axonal scaffolds evolves by precise pioneering and selective fasciculation of neural fibers in the newly formed brain neuromeres. Using an axonal marker, Fasciclin II, we show that the activities of the extradenticle (exd) and homothorax (hth) genes are essential to this axonal patterning in the embryonic brain. Both genes are expressed in the developing brain neurons, including many of the tract founder cluster cells. Consistent with their expression profiles, mutations of exd and hth strongly perturb the primary axonal scaffolds. Furthermore, we show that mutations of exd and hth result in profound patterning defects of the developing brain at the molecular level including stimulation of the orthodenticle gene and suppression of the empty spiracles and cervical homeotic genes. In addition, expression of a Drosophila Pax6 gene, eyeless, is significantly suppressed in the mutants except for the most anterior region. These results reveal that, in addition to their homeotic regulatory functions in trunk development, exd and hth have important roles in patterning the developing brain through coordinately regulating various nuclear regulatory genes, and imply molecular commonalities between the developmental mechanisms of the brain and trunk segments, which were conventionally considered to be largely independent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050316
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Coexistence of drosophilid flies: Aggregation, patch size diversity and parasitism (2000)
    Springer
    Ecological research 15 (2000), S. 93-100 
    Details
    ISSN: 1440-1703
    Keywords: aggregation ; coexistence ; Drosophila ; parasitism ; patch size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: We carried out field experiments to investigate the coexistence of Drosophila species in domestic and forest areas on the basis of the aggregation model. Three cosmopolitan species Drosophila simulans Sturtevant, Drosophila melanogaster Meigen and Drosophila immigrans Sturtevant, and a native species, Drosophila auraria Peng, emerged abundantly from banana placed at the domestic station, while Drosophila immigrans and five native species, Drosophila lutescens Okada, Drosophila rufa Kikkawa and Peng, Drosophila bizonata Kikkawa and Peng, Drosophila sternopleuralis Okada and Kurokawa and Scaptodrosophila coracina (Kikkawa and Peng), were abundant at the forest station. The present analysis suggests that their coexistence was facilitated by the aggregation mechanism. In the cosmopolitan species, the density of individuals that emerged from patches increased with the increase of patch size, but the relationship between fly density and patch size was not clear in the native species. This difference in distribution patterns between the cosmopolitan and native species is likely to be due to the difference in the female visiting behavior. In the present analysis, however, it was not clear whether patch size diversity facilitated their coexistence or not. The effect of patch size diversity may have been masked, because the effect of aggregation was more prominent. The rate of parasitism by wasps was high in October at the domestic station, and in May and June at the forest station. The present result suggests that the rate of parasitism was density-dependent, at least at the domestic station, and therefore parasitism facilitates the coexistence of drosophilid species in domestic areas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1440-1703.2000.00328.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Identification ofDrosophila mutant with memory defects after acquisition of conditioned reflex suppression of courtship (2000)
    Springer
    Neuroscience and behavioral physiology 30 (2000), S. 307-313 
    Details
    ISSN: 1573-899X
    Keywords: Memory ; suppression of courting ; Drosophila ; mutants ; P insertion mutagenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Four lines were selected from a collection of 33 lines prepared by P insertion mutagenesis using a single-copy P-element system; the males of these four lines showed memory defects after acquisition of conditioned reflex suppression of courting. In two lines (P171 and P95), the dynamics of retention of the conditioned reflex in the repeated impregnated-female courting test were similar to those of known short-term memory mutantsdnc andrut. In line P153, the dynamics were more reminiscent of the memory dynamics in a known medium-term memory mutant,amn. In line P124, the learning index was insignificant immediately after training was completed, which may indicate that this line was unable to acquire conditioned reflex suppression of courting. Determination of the positions of the P elements (P171: 48A-B; P153: 49B-C; P124; 67B–68A; P95: 77C-D) showed no correspondence with previously known mutations producing memory lesions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02471783
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Distinct requirements for the AP-3 adaptor complex in pigment granule and synaptic vesicle biogenesis in Drosophila melanogaster (2000)
    Springer
    Molecular genetics and genomics 263 (2000), S. 1003-1014 
    Details
    ISSN: 1617-4623
    Keywords: Key words AP-3 ; Biogenesis ; Pigment granule ; Synaptic vesicle ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The AP-3 adaptor protein complex has been implicated in the biogenesis of lysosome-related organelles, such as pigment granules/melanosomes, and synaptic vesicles. Here we compare the relative importance of AP-3 in the biogenesis of these organelles in Drosophila melanogaster. We report that the Drosophila pigmentation mutants orange and ruby carry genetic lesions in the σ3 and β3-adaptin subunits of the AP-3 complex, respectively. Electron microscopy reveals dramatic reductions in the numbers of electron-dense pigment granules in the eyes of these AP-3 mutants. Mutant flies also display greatly reduced levels of pigments housed in these granules. In contrast, electron microscopy of retinula cells reveals numerous synaptic vesicles in both AP-3 mutant and wild-type flies, while behavioral assays show apparently normal locomotor ability of AP-3 mutant larvae. Together, these results demonstrate that Drosophila AP-3 is critical for the biogenesis of pigment granules, but is apparently not essential for formation of a major population of synaptic vesicles in vivo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00008688
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Behavioural induction in Drosophila: timing and specificity (2000)
    Springer
    Entomologia experimentalis et applicata 94 (2000), S. 159-171 
    Details
    ISSN: 1570-7458
    Keywords: Drosophila ; induction ; habituation ; associative learning ; T-maze olfactometer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experiments reported in this paper investigate the properties of a change in the responsiveness of adult Drosophila melanogaster induced by exposure to different rearing media. This effect has previously been described as habituation or associative learning. Exposure to food medium containing 0.08% menthol induced a positive response to menthol odour in a T-maze olfactometer. A brief (one hour) exposure to mentholic food just before testing was sufficient to induce a change in responsiveness. The effect did not persist through periods of more than an hour of separation from mentholic medium. Effects induced by exposure to a single compound were not specific to that compound alone. Menthol-reared flies (MRFs) differed from plain reared flies (PRFs) in their responsiveness to the odours of benzaldehyde and ethyl acetate, as well as menthol, and exposure to ethyl acetate induced a change in response to menthol odour. That there was an induced positive response to menthol in MRFs suggests that conventional habituation is insufficient to explain the induced change in responsiveness, but the generalised nature of this behavioural induction in MRFs is hard to explain in terms of associative learning. The mechanism underlying the induction remains elusive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003998715018
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Role of AWD/Nucleoside Diphosphate Kinase in Drosophila Development (2000)
    Springer
    Journal of bioenergetics and biomembranes 32 (2000), S. 293-300 
    Details
    ISSN: 1573-6881
    Keywords: abnormal wing discs ; lethal mutant ; Drosophila ; Killer-of-prune ; prune
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The abnormal wing discs gene of Drosophila encodes a soluble protein with nucleosidediphosphate kinase activity. This enzymic activity is necessary for the biological function ofthe abnormal wing discs gene product. Complete loss of function, i.e., null, mutations causelethality after the larval stage. Most larval organs in such null mutant larvae appear to benormal, but the imaginal discs are small and incapable of normal differentiation.Killer-of-prune is a neomorphic mutation in the abnormal wing discs gene. It causes dominant lethalityin larvae that lack prune gene activity. The Killer-of-prune mutant protein may have alteredsubstrate specificity. Null mutant larvae have a low level of nucleoside diphosphate kinaseactivity. This suggests that there may be additional Drosophila genes that encode proteinswith nucleoside dipthosphate kinase activity. Candidate genes have been found in theDrosophila genome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005545214937
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Versatility of Conviction: Heterochromatin as Both a Repressor and an Activator of Transcription (2000)
    Springer
    Genetica 109 (2000), S. 19-24 
    Details
    ISSN: 1573-6857
    Keywords: chromosomal proteins ; Drosophila ; heterochromatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026544717126
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Searching for a Common Centromeric Structural Motif: Drosophila Centromeric Satellite DNAs Show Propensity to form Telomeric-Like Unusual DNA Structures (2000)
    Springer
    Genetica 109 (2000), S. 71-75 
    Details
    ISSN: 1573-6857
    Keywords: centromere ; heterochromatin ; non B-DNA structures ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The molecular basis of centromere formation in a particular chromosomal region is not yet understood. In higher eukaryotes, no specific DNA sequence is required for the assembly of the kinetochore, but similar centromeric chromatins are formed on different centromere DNA sequences. Although epigenesis has been proposed as the main mechanism for centromere specification, DNA recognition must also play a role. Through the analysis of Drosophilacentromeric DNA sequences, we found that dodeca satellite and 18HT satellite are able to form unusual DNA structures similar to those formed by telomeric sequences. These findings suggest the existence of a common centromeric structural DNA motif which we feel merits further investigation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026546510127
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Spatial differences in patterns of modification: selection on hairy in Drosophila melanogaster wings (2000)
    Springer
    Genetica 109 (2000), S. 169-181 
    Details
    ISSN: 1573-6857
    Keywords: artificial selection ; atavistic structures ; Drosophila ; pattern formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Artificial selection was carried out for over 45 generations to enhance and suppress expression of the mutation hairy on the Drosophila melanogaster wing. Whole chromosome mapping of X‐linked and autosomal modifiers of sense organ number displayed regional differences in magnitude and direction of their effects. Regional specificity of modifier effects was also seen in some interchromosomal interactions. Scanning electron microscopy allowed precise measurement of sense organ size and position along the L3 longitudinal wing vein. Sense organ size varied in a predictable fashion along the proximal–distal axis, and the dorsal pattern differed from the ventral pattern. The high and low selection lines differed most in the proximal portion of the L3 vein. Extra sense organs in the High line were often associated with vein fragments at locations predicted from ancestral vein patterns. Thus, regional specificity of polygenic or quantitative trait locus modifier effects was identified in several different parts of the wing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017531404454
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Genetic and biochemical analysis of brown eye mutation in Drosophila nasuta nasuta and Drosophila nasuta albomicans (2000)
    Springer
    Genetica 109 (2000), S. 235-243 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; brown eye ; eye pigments ; fitness ; gene localization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By analyzing the progeny of crosses involving brown eye mutants and the wild types in two members of Drosophila nasuta subgroup namely D. n. nasuta and D. n. albomicans we could show that the mutant gene is recessive, located in the chromosome 2 and the alleles of this gene are present at different loci. A study of fitness in the eye color mutants in comparison with the wild types revealed that D. n. nasuta mutant has higher viability at both 25 ± 1°C and ambient temperatures; while D. n. albomicans mutant has faster rate of development only at 25 ± 1°C. Quantitative analysis of eye pigments in the mutants revealed that there is biosynthesis of both pteridines and xanthommatins unlike in bw/bw of D. melanogaster, where only xanthommatins are synthesized. In both the species, the pteridine quantities in mutants are similar; whereas xanthommatin quantity in $$\user1{bw}_n \user1{/bw}_n$$ is 10 times higher than that of $$\user1{bw}_a \user1{/bw}_a$$ . Further, the F1 progeny of intraspecific crosses (wild type X mutant) are found to have high amounts of pteridine, even when compared with parental wild type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017505400086
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Distribution of the Transposable Element Minos in the Genus Drosophila (2000)
    Springer
    Genetica 108 (2000), S. 263-267 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; horizontal transfer ; Minos ; Tc1-like ; Tc1-marinerfamily ; transposable elements ; transposon distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We analyzed 28 species of the genus Drosophilafor the presence of the Tc1-like transposable element Minosusing Southern blot hybridization under high stringency conditions. The Minostransposon was found in members of both the Drosophilaand the Sophophorasubgenus showing a distribution that is wider if compared to other well-studied Drosophilatransposons such as the Pelement, hoboand mariner. The presence of Minos-hybridizing sequences was discontinuous in the Sophophorasubgenus, especially in the melanogasterspecies group. Using the Polymerase Chain Reaction we amplified a portion corresponding to the putative Minostransposase from different Drosophilaspecies. Cloning and sequence analysis of randomly selected Minoscopies from D. mojavensisis, D. saltansand D. willistonisupports the idea that event(s) of horizontal transfer may have contributed to the spreading of this transposon in the Drosophilagenus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004185024017
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Impact of Multiple Insertions of two Retroelements, ZAM and Idefix at an Euchromatic Locus (2000)
    Springer
    Genetica 109 (2000), S. 53-59 
    Details
    ISSN: 1573-6857
    Keywords: chromatin structure ; Drosophila ; mutagenic effect ; retroelements ; white
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transposable elements represent a large fraction of eukaryotic genomes and they are thought to play an important role in chromatin structure. ZAMand Idefixare two LTR-retrotransposons from Drosophila melanogastervery similar in structure to vertebrate retroviruses. In all the strains where their distribution has been studied, ZAMappears to be present exclusively in the intercalary heterochromatin while Idefixcopies are mainly found in the centromeric heterochromatin with very few copies in euchromatin. Their distribution varies in a specific strain called RevI in which the mobilization of ZAMand Idefixis highly induced. In this strain, 15 copies of ZAMand 30 copies of Idefixare found on the chromosomal arms in addition to their usual distribution. Amongst the loci where new copies are detected, a hotspot for their insertion has been detected at the whitelocus where up to four elements occurred within a 3-kb fragment at the 5′ end of this gene. This property of ZAMand Idefixto accumulate at a defined site provides an interesting paradigm to bring insight into the effect exerted by multiple insertions of transposable elements at an euchromatic locus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026534207401
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Genetic analysis of extended lifespan in Drosophila melanogaster III. On the relationship between artificially selected and wild stocks (2000)
    Springer
    Genetica 109 (2000), S. 245-253 
    Details
    ISSN: 1573-6857
    Keywords: artificial selection ; Drosophila ; lifespan ; mortality ; paraquat ; DDT ; recovery hypothesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adult lifespans, age‐specific survival, age‐specific mortality, survival times on paraquat, and survival times on DDT were assayed in seven lines of Drosophila melanogaster, including two genetically heterogeneous wild lines recently collected from nature, and three inbred and recombinant inbred lines derived from an artificial selection experiment for increased lifespan. Survival on paraquat is positively correlated with adult lifespan. DDT resistance is uncorrelated with either paraquat resistance or lifespan. The wild lines are unexceptional with respect to average lifespan, paraquat resistance, age‐specific survivorship, and leveling off of mortality rates at advanced ages, but have high levels of DDT resistance. Cluster analysis groups the wild lines with three unselected laboratory stocks in one cluster, while two long‐lived elite recombinant inbred lines form a second cluster. Long‐lived laboratory‐adapted lines are quantitatively differentiated from the wild stocks, both with respect to average adult lifespans and resistance to an oxidizing agent. We reject the ‘recovery’ hypothesis, which proposes that Drosophila artificially selected for long life have phenotypes that merely recover the wild state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017569318401
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Genetic variance in temperature dependent adult size deriving from physiological genetic variation at temperature boundaries (2000)
    Springer
    Genetica 110 (2000), S. 195-207 
    Details
    ISSN: 1573-6857
    Keywords: biophysics ; body size ; Drosophila ; ectotherm ; genetic variance ; stress ; temperature extreme
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An increase in genetic variation in body size has often been observed under stress; an increase in dominance variance and interaction variance as well as in additive genetic variance has been reported. The increase in genetic variation must be caused by physiological mechanisms that are specific to adverse environments. A model is proposed to explain the occurrence of an increase in genetic variation in body size in Drosophila at extreme temperatures. The model has parameters specific to the low- and high-temperature regions of the viable range. Additive genetic variation in the boundary temperatures leads to a marked increase in additive genetic variation in development rate and body size at extreme temperatures. Additive genetic variation in the temperature sensitivity in the low- and high-temperature regions adds non-additive genetic variation. Development rate shows patterns in additive genetic variation that differ from the patterns of genetic variation in body size; therefore, the genetic correlation between development rate and body size changes sign repeatedly as a function of temperature. The existence of dominance in the genetic variation in the boundary temperatures or in the low- and high-temperature sensitivities leads to a higher total genetic variance due to higher dominance and interaction variance, for both development rate and body size.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017974618477
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Common Mechanisms of Y Chromosome Evolution (2000)
    Springer
    Genetica 109 (2000), S. 105-111 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; evolution ; heterochromatin ; Y chromosome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Y chromosome evolution is characterized by the expansion of genetic inertness along the Y chromosome and changes in the chromosome structure, especially the tendency of becoming heterochromatic. It is generally assumed that the sex chromosome pair has developed from a pair of homologues. In an evolutionary process the proto-Y-chromosome, with a very short differential segment, develops in its final stage into a completely heterochromatic and to a great extends genetically eroded Y chromosome. The constraints evolving the Y chromosome have been the objects of speculation since the discovery of sex chromosomes. Several models have been suggested. We use the exceptional situation of the in Drosophila mirandato analyze the molecular process in progress involved in Y chromosome evolution. We suggest that the first steps in the switch from a euchromatic proto-Y-chromosome into a completely heterochromatic Y chromosome are driven by the accumulation of transposable elements, especially retrotransposons inserted along the evolving nonrecombining part of the Y chromosome. In this evolutionary process trapping and accumulation of retrotransposons on the proto-Y-chromosome should lead to conformational changes that are responsible for successive silencing of euchromatic genes, both intact or already mutated ones and eventually transform functionally euchromatic domains into genetically inert heterochromatin. Accumulation of further mutations, deletions, and duplications followed by the evolution and expansion of tandem repetitive sequence motifs of high copy number (satellite sequences) together with a few vital genes for male fertility will then represent the final state of the degenerated Y chromosome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026584016524
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Parental Imprinting in Drosophila (2000)
    Springer
    Genetica 109 (2000), S. 35-44 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; heterochromatin ; imprinting ; parental effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetic imprinting is a form of epigenetic silencing. But with a twist. The twist is that while imprinting results in the silencing of genes, chromosome regions or entire chromosome sets, this silencing occurs only after transmission of the imprinted region by one sex of parent. Thus genetic imprinting reflects intertwined levels of epigenetic and developmental modulation of gene expression. Imprinting has been well documented and studied in Drosophila, however, these studies have remained largely unknown due to nothing more significant than differences in terminology. Imprinting in Drosophilais invariably associated with heterochromatin or regions with unusual chromatin structure. The imprint appears to spread from imprinted centers that reside within heterochromatin and these are, seemingly, the only regions that are normally imprinted in Drosophila. This is significant as it implies that while imprinting occurs in Drosophila, it is generally without phenotypic consequence. Hence the evolution of imprinting, at least in Drosophila, is unlikely to be driven by the function of specific imprinted genes. Thus, the study of imprinting in Drosophilahas the potential to illuminate the mechanism and biological function of imprinting, and challenge models based solely on imprinting of mammalian genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026592318341
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Control of Telomere Elongation and Telomeric Silencing in Drosophila Melanogaster (2000)
    Springer
    Genetica 109 (2000), S. 61-70 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; heterochromatin ; telomere ; transcription ; transposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chromosome length in Drosophilais maintained by the targeted transposition of two families of non-LTR retrotransposons, HeT-Aand TART. Although the rate of transposition to telomeres is sufficient to counterbalance loss from the chromosome ends due to incomplete DNA replication, transposition as a mechanism for elongating chromosome ends raises the possibility of damaged or deleted telomeres, because of its stochastic nature. Recent evidence suggests that HeT-Atransposition is controlled at the levels of transcription and reverse transcription. HeT-Atranscription is found primarily in mitotically active cells, and transcription of a w +reporter gene inserted into the 2L telomere increases when the homologous telomere is partially or completely deleted. The terminal HeT-Aarray may be important as a positive regulator of this activity in cis, and the subterminal satellite appears to be an important negative regulator in cis. A third chromosome modifier has been identified that increases the level of reverse transcriptase activity on a HeT-A RNA template and greatly increases the transposition of HeT-A. Thus, the host appears to play a role in transposition of these elements. Taken together, these results suggest that control of HeT-Atransposition is more complex than previously thought.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026548503320
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Drosophila Telomeric Transgenes Provide Insights on Mechanisms of Gene Silencing (2000)
    Springer
    Genetica 109 (2000), S. 25-33 
    Details
    ISSN: 1573-6857
    Keywords: chromatin ; Drosophila ; heterochromatin ; position effect variegation ; telomeres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A significant fraction of most eukaryotic genomes is packaged into chromatin that is not permissive for gene expression. This silent chromatin is typically located near centromeres and telomeres and has fascinated scientists for more than 70 years, yet many questions remain unanswered. Part of the difficulties in studying silent chromatin at the molecular level is the repetitive nature of the DNA sequences in these regions. To overcome this problem, Drosophilastocks carrying in vitrodesigned transgenes inserted within silent chromatin have been generated. Molecular analysis of these transgenes has shed light on the nature of the chromatin structure within these regions and provided insights on the mechanisms of gene silencing. This review will focus on recent studies using telomeric transgenes. The results from these studies suggest that nuclear organization plays a role in gene silencing and that silencing is the result of a block early in the process of transcription initiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026556705137
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Molecular organization of the Drosophila melanogaster Adh chromosomal region in D. replete and D. buzzatii, two distantly related species of the Drosophila subgenus (2000)
    Springer
    Chromosome research 8 (2000), S. 375-385 
    Details
    ISSN: 1573-6849
    Keywords: Adh ; Drosophila ; FISH ; genome evolution ; repleta group
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The molecular organization of a 1.944-Mb chromosomal region of Drosophila melanogaster around the Adh locus has been analyzed in two repleta group species: D. repleta and D. buzzatii. The extensive genetic and molecular information about this region in D. melanogaster makes it a prime choice for comparative studies of genomic organization among distantly related species. A set of 26 P1 phages from D. melanogaster were successfully hybridized using fluorescence in-situ hybridization (FISH) to the salivary gland chromosomes of both repleta group species. The results show that the Adh region is distributed in D. repleta and D. buzzatii over six distant sites of chromosome 3, homologous to chromosomal arm 2L of D. melanogaster (Muller's element B). This observation implies a density of 2.57 fixed breakpoints per Mb in the Adh region and suggests a considerable reorganization of this chromosomal element via the fixation of paracentric inversions. Nevertheless, breakpoint density in the Adh region is three times lower than that estimated for D. repleta chromosome 2, homologous to D. melanogaster 3R (Muller's element E). Differences in the rate of evolution among chromosomal elements are seemingly persistent in the Drosophila genus over long phylogenetic distances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009206702214
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Dnop56, a Drosophila gene homologous to the yeast nucleolar NOP56 gene (2000)
    Springer
    Genetica 109 (2000), S. 275-282 
    Details
    ISSN: 1573-6857
    Keywords: DmNop56 ; DsNop56 ; Drosophila ; molecular evolution ; snoRNPs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Small nucleolar RNAs (snoRNAs) are trans‐acting factors involved in maturation of rRNA and have been classified into Box C/D and Box H/ACA families. Most of the snoRNAs occur as ribonucleoprotein complexes with snoRNA‐associated proteins (snoRNPs). All Box C/D snoRNAs in yeast form complexes with Nop1p, Nop56p and Nop58p. Similarly, it has been reported that Box H/ACA‐containing snoRNAs form complexes with yeast Gar1p. Nop56p and Nop58p homologs have been described in several species. Here we report the isolation and molecular characterization of the Dnop56 genes from D. melanogaster and D. subobscura which show a very similar structure. Drosophila Nop56p proteins contain lysine‐rich regions at their carboxy‐terminus, and show a high degree of similarity to other Nop56p proteins from different organisms. Phylogenetic relationships among these proteins and other snoRNPs have been established.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017596312331
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    An episode of accelerated amino acid change in Drosophila esterase-6 associated with a change in physiological function (2000)
    Springer
    Genetica 110 (2000), S. 231-244 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; , esterase-6 ; function ; sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In most lineages of the subgenus Sophophora esterase-6 is a homodimeric haemolymph protein. In the melanogaster subgroup of species it has become a monomer which is mainly expressed in the male sperm ejaculatory duct. Our analyses of esterase-6 sequences from three melanogaster subgroup species and two close relatives reveal a brief period of accelerated amino acid sequence change during the transition between the ancestral and derived states. In this period of 2–6Myr the ratio of replacement to silent site substitutions (0.51) is about three times higher than the values in other lineages of the phylogeny. There are about 50 more replacements in this period than would be predicted from the ratios of replacement to silent site substitutions found elsewhere in the phylogeny. Modelling on the known structure of a related acetylcholinesterase suggests that an unusually high proportion of the replacements in the transitional branch are non-conservative changes on the protein surface. Up to half the accelerated replacement rate can be accounted for by clusters of changes to the face of the molecule containing the opening of the active site gorge. This includes changes in and around regions homologous to peripheral substrate binding sites in acetylcholinesterase. There are also three changes in glycosylation status. One region predicted to lie on the protein surface which becomes markedly more hydrophilic is proposed to be the ancestral dimerisation site that is lost in the transitional branch.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1012727814167
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Variations of male cuticular hydrocarbons with geoclimatic variables: an adaptative mechanism in Drosophila melanogaster? (2000)
    Springer
    Genetica 110 (2000), S. 117-130 
    Details
    ISSN: 1573-6857
    Keywords: adaptation ; Drosophila ; hydrocarbons ; latitude ; longitude ; natural populations ; polymorphism ; temperaturey ; vapour pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 7-tricosene (7T) and 7-pentacosene (7P) are the major components of cuticular hydrocarbons in Drosophila simulans and D. melanogaster males. A chemical study of 16 isofemale lines of D. melanogaster sampled at the first and eighth generations in laboratory conditions showed the stability of chromatographical profiles. Then a large scale study of male 7T/7P polymorphism was performed with 85 populations of D. melanogaster and 29 of D. simulans collected all over the world. There were significant correlations of the values of the balanced ratio (7T − 7P)/(7T + 7P) with geo-climatic parameters, such as latitude, longitude, mean temperature, temperature range and vapour pressure. Parallel variations were also reported for the homologous linear alkanes (23 and 25 Carbon atoms) but not for the longer branched alkanes (27 and 29 Carbon atoms). No correlation was significant for the D. simulans populations studied. In this species a similar polymorphism of 7T/7P was found but restricted to a few populations from West Equatorial Africa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017987220814
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Lack of Evolutionary Divergence in Courtship Songs of Drosophila pseudoobscura Subspecies (2000)
    Springer
    Journal of insect behavior 13 (2000), S. 255-262 
    Details
    ISSN: 1572-8889
    Keywords: courtship song ; wingbeat ; sexual isolation ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007744416116
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Copulatory Courtship in Drosophila birchii and D. serrata, Species Recognition and Sexual Selection (2000)
    Springer
    Journal of insect behavior 13 (2000), S. 361-373 
    Details
    ISSN: 1572-8889
    Keywords: Drosophila ; copulatory courtship ; mate choice ; cryptic female choice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two endemic Australian Drosophila species, D. birchii and D. serrata, have a copulatory courtship, i.e., the males court the female mainly during copulation. In the present study we found the males of both species to mount their prospective mating partners selectively, exhibiting both sex and species recognition. The males began to sing after mounting the female, and they often exhibited also postcopulatory displays typical to copulatory courtship. D. birchii and D. serrata females discriminated against males which did not sing during mounting/copulation, which suggests that the females utilize cryptic female choice. Our findings raise the question of how widespread a phenomenon cryptic female choice is in Drosophila species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007710218609
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Behavioral Characterization and Genetic Analysis of the Drosophila melanogaster Larval Response to Light as Revealed by a Novel Individual Assay (2000)
    Springer
    Behavior genetics 30 (2000), S. 59-69 
    Details
    ISSN: 1573-3297
    Keywords: Insect ; larval photobehavior ; locomotion ; Drosophila ; behavioral mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract A new assay was designed, named checker, that measures the individual response to light in the fruitfly Drosophila melanogaster larva. In this assay the Drosophila larva apparently modulates its pattern of locomotion when faced with a choice between a dark and lit environment by orienting its movement towards the dark environment. We show that, in this assay, a response to light can be measured as an increase in residence time in the dark versus the lit quadrant. Mutations that disrupt phototransduction in the adult Drosophila abolish the larval response to light, demonstrating that this larval visual function is similar to that of the adult fly. Similarly, no response to light was detected in strains where the larval visual system (photoreceptors and target area) was disrupted by a mutation in the homeobox containing gene sine oculis (so) gene. Ablation of photoreceptors by the targeted expression of the cell death gene hid under the control of the photoreceptor-specific transcription factor glass (gl) abolishes this response entirely. Finally, we demonstrate that this response to light can be mediated by rhodopsins other than the blue absorbing Rh1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1002090627601
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Regulation of Mst57Dc Expression in Male Accessory Glands of Dorsophila melanogaster (2000)
    Springer
    Molecules and cells 10 (2000), S. 180-185 
    Details
    ISSN: 0219-1032
    Keywords: Drosophila ; Gene Expression ; JHRE ; Juvenile Hormone ; Male Accessory Gland ; Mst57Dc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mst57Dc has been isolated as a male accessory gland transcript of Drosophila melanogaster. Its product is a secretory protein, which is phosphorylated by protein kinase A. In the present study, the expression pattern of Mst57Dc was analyzed. It is preferentially expressed in but not restricted to the male accessory glands. Other than in the accessory glands, it is slightly expressed in other body parts, including the head and female body. In the accessory glands, a high level of expression was detected right after eclosion when the titer of juvenile hormone III (JHIII) reaches a peak. Its accumulation was increased by mating, which has been known to act via JH. In ap56f, a JH-deficient mutant, the level of Mst57Dc transcripts was about 60% of the wild type. Moreover a JH-responsive element like palindromic sequence and several sequence motifs were found in the 5′ and 3′ flanking regions of Mst57Dc. Taken together, JH is proposed as a regulator of Mst57Dc gene expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10059-000-0180-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Isolation of True Rbp9 Null Alleles by Imprecise P Element Excisions (2000)
    Springer
    Molecules and cells 10 (2000), S. 61-64 
    Details
    ISSN: 0219-1032
    Keywords: Drosophila ; Imprecise Excision ; Null Allele ; P Element ; Rbp9
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The P element has been widely used as a mutagen because of its convenience in locating the site of mutagenesis. However, P element-induced mutations often result in varied mutant phenotypes, making it difficult to identify the null phenotype. Previously, three Rbp9 alleles were isolated using P element mutagenesis. Although the coding regions of Rbp9 were disrupted by P elements in all three cases, they showed different degrees of defects. In order to characterize the null phenotype of Rbp9, Rbp9 alleles with chromosomal deletions were created by inducing imprecise excisions of the P elements. All Rbp9 alleles generated from imprecise excisions showed the same mutant phenotype: female flies were sterile and cystocyte differentiation was blocked. This result reveals that the primary function of Rbp9 resides in the regulation of cystocyte differentiation. In addition, this result shows that a P element does not always completely inactivate gene activity, even when it is incorporated into the coding region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10059-000-0061-1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Effects of Polycomb Group Mutations on the Expression of Ultrabithorax in the Drosophila Visceral Mesoderm (2000)
    Springer
    Molecules and cells 10 (2000), S. 156-161 
    Details
    ISSN: 0219-1032
    Keywords: Drosophila ; Polycomb Group Genes ; Ultrabithorax ; Visceral Mesoderm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Polycomb group (PcG) genes encode repressors of many developmental regulatory genes including homeotic genes and are known to act by modifying chromatin structure through complex formation. We describe how Ultrabithorax (Ubx) expression is affected by the PcG mutants in the visceral mesoderm. Mutant embryos of the genes extra sex combs (esc), Polycomb (Pc), additional sex combs (Asx) and pleiohomeotic (pho) were examined. In each mutation, Ubx was ectopically expressed outside of their normal domains along the anterior-posterior axis in the visceral mesoderm, which is consistent with the effect of PcG proteins repressing the homeotic genes in other tissues. All of these four PcG mutations exhibit complete or partial lack of midgut constriction. However, two thirds of esc mutant embryos did not show Ubx expression in parasegment 7 (PS7). Even in the embryos showing ectopic Ubx expression, the level of Ubx expression in the PcG mutations was weaker than that in normal embryos. We suggest that in PcG mutations the ectopic Ubx expression is caused by lack of PcG repressor proteins, while the weaker or lack of Ubx expression is due to the repression of Ubx by Abd-B protein which is ectopically expressed in PcG mutations as well.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10059-000-0156-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Calcium-binding Proteins Calbindin D28K, Calretinin, and Parvalbumin Immunoreactivity in the Rabbit Visual Cortex (2000)
    Springer
    Molecules and cells 10 (2000), S. 206-212 
    Details
    ISSN: 0219-1032
    Keywords: Calcium-binding Protein ; Immunocytochemistry ; Localization ; Visual Cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The distribution and morphology of neurons containing three calcium-binding proteins, calbindin D28K, calretinin, and parvalbumin in the adult rabbit visual cortex were studied. The calcium-binding proteins were identified using antibody immunocytochemistry. Calbindin D28K-immunoreactive (IR) neurons were located throughout the cortical layers with the highest density in layer V. However, calbindin D28K-IR neurons were rarely encountered in layer I. Calretinin-IR neurons were mainly located in layers II and III. Considerably lower densities of calretinin-IR neurons were observed in the other layers. Parvalbumin-IR neurons were predominantly located in layers III, IV, V, and VI. In layers I and II, parvalbumin-IR neurons were only rarely seen. The majority of the calbindin D28K-IR neurons were stellate, round or oval cells with multipolar dendrites. The majority of calretinin-IR neurons were vertical fusiform cells with long processes traveling perpendicularly to the pial surface. The morphology of the majority of parvalbumin-IR neurons was similar to that of calbindin D28K: stellate, round or oval with multipolar dendrites. These results indicate that these three different calcium-binding proteins are contained in specific layers and cells in the rabbit visual cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10059-000-0206-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Calmodulin-dependent and -independent apoptosis in cells of a Drosophila neuronal cell line (2000)
    Springer
    Apoptosis 5 (2000), S. 133-140 
    Details
    ISSN: 1573-675X
    Keywords: Apoptosis ; calmodulin ; caspases ; cell line ; Drosophila ; neuron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract This study was undertaken to reveal apoptotic pathways in neurons using a Drosophila neuronal cell line derived from larval central nervous system. We could induce apoptotic cell death in the cells by a Ca2+ ionophore (A23187), a protein kinase inhibitor (H-7), an RNA synthesis inhibitor (actinomycin D) and a protein synthesis inhibitor (cycloheximide). All the apoptosis induced by each chemical required Ca2+ ions, although the origin of Ca2+ ions were different: apoptosis induced by A23187 was dependent on extracellular Ca2+ ions whereas those by the other three chemicals utilized intracellular Ca2+ ions. Furthermore, different reactions to W-7, a calmodulin inhibitor, were found: W-7 prevented the cell death by each of the three chemicals but not by A23187. Based on the results, we proposed that the apoptotic pathways are classified into two types in individual cells. One pathway induced by H-7, actinomycin D or cycloheximide is calmodulin-dependent (pathway H), and another induced by A23187 is calmodulin-independent (pathway A).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009676528805
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Immunocytochemical characterization of early-developing flax fiber cell walls (2000)
    Springer
    Protoplasma 213 (2000), S. 235-245 
    Details
    ISSN: 1615-6102
    Keywords: Arabinogalactan proteins ; Fiber ; Linum usitatissimum ; Immunocytochemistry ; Polysaccharide ; Secondary wall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The deposition and formation of a thick secondary wall is a major event in the differentiation of flax (Linum usitatissimum) fibers. This wall is cellulose-rich; but it also contains significant amounts of other matrix polymers which are noncellulosic such as pectins. We have used immunocytochemical techniques with antibodies specific for various epitopes associated with either pectins or arabinogalactan proteins (AGPs) to investigate the distribution of these polymers within the walls of differentiating young fibers of 1- and 2-week-old plants. Our results show that different epitopes exhibit distinct distribution patterns within fiber walls. Unesterified pectins recognized by polygalacturonic acid-rhamnogalacturonan I (PGA/RG-I) antibodies and rhamnogalacturonan II recognized by anti-RG-II-borate complex antibodies are localized all over the secondary wall of fibers. PGA/RG-I epitopes, but not RG-II epitopes, are also present in the middle lamellae and cell junctions. In marked contrast, β-(1→4) galactans recognized by the LM5 monoclonal antibody and AGP epitopes recognized by anti-β-(1→6) galactan and LM2 antibodies are primarily located in the half of the secondary wall nearest the plasma membrane. LM2 epitopes, present in 1-week-old fibers, are undetectable later in development, suggesting a regulation of the expression of certain AGP epitopes. In addition, localization of cellulose with the cellobiohydrolase I-gold probe reveals distinct subdomains within the secondary walls of young fibers. These findings indicate that, in addition to cellulose, early-developing flax fibers synthesize and secrete different pectin and AGP molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01282161
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Role of Notch pathway in terminal follicle cell differentiation during Drosophila oogenesis (1999)
    Springer
    Development genes and evolution 209 (1999), S. 301-311 
    Details
    ISSN: 1432-041X
    Keywords: Key words Delta ; Notch ; Follicle cells ; Oogenesis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  During Drosophila oogenesis the body axes are determined by signaling between the oocyte and the somatic follicle cells that surround the egg chamber. A key event in the establishment of oocyte anterior-posterior polarity is the differential patterning of the follicle cell epithelium along the anterior-posterior axis. Both the Notch and epithelial growth factor (EGF) receptor pathways are required for this patterning. To understand how these pathways act in the process we have analyzed markers for anterior and posterior follicle cells accompanying constitutive activation of the EGF receptor, loss of Notch function, and ectopic expression of Delta. We find that a constitutively active EGF receptor can induce posterior fate in anterior but not in lateral follicle cells, showing that the EGF receptor pathway can act only on predetermined terminal cells. Furthermore, Notch function is required at both termini for appropriate expression of anterior and posterior markers, while loss of both the EGF receptor and Notch pathways mimic the Notch loss-of-function phenotype. Ectopic expression of the Notch ligand, Delta, disturbs EGF receptor dependent posterior follicle cell differentiation and anterior-posterior polarity of the oocyte. Our data are consistent with a model in which the Notch pathway is required for early follicle cell differentiation at both termini, but is then repressed at the posterior for proper determination of the posterior follicle cells by the EGF receptor pathway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050256
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Neural expression of hikaru genki protein during embryonic and larval development of Drosophila melanogaster (1999)
    Springer
    Development genes and evolution 209 (1999), S. 1-9 
    Details
    ISSN: 1432-041X
    Keywords: Key words Synapse ; Drosophila ; Immunoglobulin superfamily ; Axonal transport ; Neurosecretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Hikaru genki (HIG) is a putative secreted protein of Drosophila that belongs to immunoglobulin and complement-binding protein superfamilies. Previous studies reported that, during pupal and adult stages, HIG protein is synthesized in subsets of neurons and appears to be secreted to the synaptic clefts of neuron-neuron synapses in the central nervous system (CNS). Here we report the analyses of distribution patterns of HIG protein at embryonic and larval stages. In embryos, HIG was mainly observed in subsets of neurons of the CNS that include pCC interneurons and RP5 motorneurons. At third instar larval stage, this protein was detected in a limited number of cells in the brain and ventral nerve cord. Among them are the motorneurons that extend their axons to make neuromuscular junctions on body wall muscle 8. Immunoelectron microscopy showed that these axonal processes as well as the neuromuscular terminals contain numerous vesicles with HIG staining, suggesting that HIG is in a pathway of secretion at this stage. Some neurosecretory cells were also found to express this protein. These data suggest that HIG functions in the nervous system through most developmental stages and may serve as a secreted signalling molecule to modulate the property of synapses or the physiology of the postsynaptic cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050221
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Dynamic features of adherens junctions during Drosophila embryonic epithelial morphogenesis revealed by a Dα-catenin-GFP fusion protein (1999)
    Springer
    Development genes and evolution 209 (1999), S. 218-225 
    Details
    ISSN: 1432-041X
    Keywords: Key words α-catenin ; Drosophila ; Green fluorescent protein (GFP) ; Adherens junction ; Epithelial morphogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Cell-cell adherens junctions (AJs), comprised of the cadherin-catenin adhesion system, contribute to cell shape changes and cell movements in epithelial morphogenesis. However, little is known about the dynamic features of AJs in cells of the developing embryo. In this study, we constructed Dα-catenin fused with a green fluorescent protein (Dα-catenin-GFP), and found that it targeted apically located AJ-based contacts but not other lateral contacts in epithelial cells of living Drosophila embryos. Using time-lapse fluorescence microscopy, we examined the dynamic performance of AJs containing Dα-catenin-GFP in epithelial morphogenetic movements. In the ventral ectoderm of stage 11 embryos, concentration and deconcentration of Dα-catenin-GFP occurred concomitantly with changes in length of AJ contacts. In the lateral ectoderm of embryos at the same stage, dynamic behaviour of AJs was concerted with division and delamination of sensory organ precursor (SOP) cells. Moreover, changes in patterns of AJ networks during tracheal extension could be followed. Finally, we utilized Dα-catenin-GFP to precisely observe the defects in tracheal fusion in shotgun mutants. Thus, the Dα-catenin-GFP fusion protein is a helpful tool to simultaneously observe morphogenetic movements and AJ dynamics at high spatio-temporal resolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050246
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Characterization of the Tribolium Deformed ortholog and its ability to directly regulate Deformed target genes in the rescue of a Drosophila Deformed null mutant (1999)
    Springer
    Development genes and evolution 209 (1999), S. 389-398 
    Details
    ISSN: 1432-041X
    Keywords: Key words Deformed ; Drosophila ; Embryogenesis ; Tribolium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We have analyzed the Tribolium castaneum ortholog of the Drosophila homeotic gene Deformed (Dfd) and determined its expression pattern during embryogenesis in this beetle. Tc Deformed (Tc Dfd) is expressed in the blastoderm and the condensing germ rudiment in a region that gives rise to gnathal segments. During germ band extension Tc Dfd is expressed in the mandibular and maxillary segments, their appendages, and the dorsal ridge. Comparison of insect Dfd protein sequences reveals several highly conserved regions. To determine whether common molecular features reflect conserved regulatory functions we used the Gal4 system to express the Tribolium protein in Drosophila embryos. When Tc Dfd is expressed throughout embryonic ectoderm under the control of P69B, the beetle protein autoregulates the endogenous Dfd gene. In addition, the Drosophila proboscipedia gene (a normal target of Dfd) is ectopically activated in the antennal and thoracic segments. We also compared the ability of the beetle and fly proteins to rescue defects in Dfd – mutants by expressing each throughout the embryonic during embryogenesis. Both proteins rescued Dfd – defects to the same extent in that they each restore the development of mouth hooks and cirri, as well as cause gain-of-function abnormalities of posterior mouth parts. As before, pb was ectopically activated in the antennal segment. This is the first demonstration of the ability of a heterologous homeotic selector protein to directly regulate a target gene independent of an endogenous Drosophila autoregulatory loop.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050269
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Distinct expression patterns of different Enhancer of split bHLH genes during embryogenesis of Drosophila melanogaster (1999)
    Springer
    Development genes and evolution 209 (1999), S. 370-375 
    Details
    ISSN: 1432-041X
    Keywords: Key words bHLH genes ; Drosophila ; Embryogenesis ; Enhancer of split ; Notch pathway
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  E(spl) bHLH genes are targets of the Notch pathway: they are transcriptionally activated in response to the Notch signal. Yet, during imaginal development, additional regulatory factors appear to modulate transcription resulting in different expression patterns. During early embryogenesis all E(spl) bHLH genes are expressed in roughly the same domain, namely the neurogenic ectoderm. Within this region these seven genes show a highly dynamic, yet distinct transcriptional activity. Our analysis further detected tissue specific expression of some E(spl) genes at later embryonic stages. Prominent differences were observed in the dorsolateral and procephalic neuroectodermal regions as well as in the mesoderm. These observations indicate that other factors in addition to the Notch signal participate in the regulation of the individual E(spl) genes not only in imaginal tissues but also during neuroblast specification and other cell fate determination events in the embryo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050266
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Cambium: old challenges – new opportunities (1999)
    Springer
    Trees 13 (1999), S. 138-151 
    Details
    ISSN: 0931-1890
    Keywords: Key words Cytoskeleton ; Immunocytochemistry ; Model systems ; Populus ; Secondary vascular system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Trees represent a, probably the, major component of the biosphere and have a unique place in the history of Mankind. One of their most fascinating features is the process of secondary growth which is effected principally by the secondary vascular system, the developmental continuum of secondary phloem, vascular cambium, and secondary xylem. However, for too long assumptions about the developmental biology of trees have had to be based upon studies of primary growth systems within annual, herbaceous species because study of the secondary vascular system had been largely ignored. Even when attempts are made to understand some of the most fundamental features of the secondary vascular system, such as xylogenesis, the current model system, isolated Zinnia mesophyll cells, is not entirely appropriate to the situation in the intact tree. Some deficiencies of the Zinnia system are discussed, and the advantages of the genus Populus as a model for study of the hardwood secondary vascular system are considered. Some of the new approaches which are poised to lead to significant advances in our knowledge of the cell bio-logy of the secondary vascular system of trees – spe-cifically of the cell wall, the plasmalemma, and the cytoskeleton – are discussed. The value of one of these new techniques – immunocytochemistry – is demonstrated by a consideration of recent work on the role of the cytoskeleton in the hardwood secondary vascular system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00009745
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Epidermal growth factor receptor: its role in Drosophila eye differentiation and cell survival (1999)
    Springer
    Apoptosis 4 (1999), S. 239-243 
    Details
    ISSN: 1573-675X
    Keywords: Apoptosis ; cell survival ; differentiation ; Drosophila ; EGFR ; hid ; ras.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The Drosophila epidermal growth factor receptor (EGFR), functioning through the Ras/Raf/MAPK pathway, promotes cell proliferation and differentiation. Recent work has demonstrated that EGFR functions via the same Ras/Raf/MAPK pathway to promote cell survival. This review summarizes the role of EGFR in differentiation and survival during Drosophila eye development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009648724937
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Identification of nuclear genes encoding mitochondrial proteins: isolation of a collection of D. melanogaster cDNAs homologous to sequences in the Human Gene Index database (1999)
    Springer
    Molecular genetics and genomics 261 (1999), S. 64-70 
    Details
    ISSN: 1617-4623
    Keywords: Key words Mitochondrial proteins ; Nuclear genes ; Drosophila ; Evolutionary conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract As a first step towards using cross-species comparison to complete the inventory of the nuclear genes that encode mitochondrial polypeptides, and ultimately to understand their function through systematic molecular and genetic analysis in a model organism of choice, we report here the characterization of 41 Drosophila melanogaster cDNAs. These cDNAs were isolated by screening an ovarian expression library with antibodies against mitochondrial proteins and identify 17 novel Drosophila genes. The deduced amino acid sequences encoded by the majority of these cDNAs turned out to show significant homology to mitochondrial proteins previously identified in other species. Among others, ORFs putatively encoding six different subunits of ATP synthase and three NADH:ubiquinone reductase subunits were detected. By in situ hybridization, all cDNAs were mapped to single bands on polytene chromosomes, thus identifying candidate Drosophila genes required for mitochondrial biogenesis and maintenance. A search of the Human Gene Index database made it possible in most cases to align the entire Drosophila coding sequence with a human consensus sequence, suggesting that the cDNAs originate from insect counterparts of expressed mammalian genes. Our experimental strategy represents an efficient approach to the identification and interspecies comparison of genes encoding products targeted to the mitochondrion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380050942
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    The Drosophila cinnamon gene is functionally homologous to Arabidopsis cnx1 and has a similar expression pattern to the mammalian gephyrin gene (1999)
    Springer
    Molecular genetics and genomics 261 (1999), S. 672-680 
    Details
    ISSN: 1617-4623
    Keywords: Key words Molybdenum cofactor biosynthesis ; Drosophila ; cinnamon ; cnx1 ; GEPHYRIN
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Molybdoenzymes are involved in a variety of essential pathways including nitrate assimilation, sulfur and/or purine metabolism and abscisic acid biosynthesis. Most organisms produce several such enzymes requiring a molybdopterin cofactor for catalytic function. Mutations that result in a lack of the molybdopterin cofactor display a pleiotropic loss of molybdoenzyme activities, and this phenotype has been used to identify genes involved in cofactor biosynthesis or utilization. Although several cofactor genes have been analyzed in prokaryotes, much less is known concerning eukaryotic molybdenum cofactor (MoCF) genes. This work is focused on the Drosophila MoCF gene cinnamon (cin) which encodes a multidomain protein, CIN, that shows significant similarity to three proteins encoded by separate prokaryotic MoCF genes. These domains are also present in the product of cnx1, an Arabidopsis MoCF gene, and in GEPHYRIN, a rat protein thought to organize the glycine receptor, GlyR, within the postsynaptic membrane. Since this apparent consolidation of separate prokaryotic genes into a single eukaryotic gene is a feature of other conserved metabolic pathways, we wished to determine whether the protein's function is also conserved. This report shows that the plant gene cnx1 can rescue both enzymatic and physiological defects of Drosophila carrying cin mutations, indicating that the two genes serve similar or identical functions. In addition, we have investigated the relationship between CINNAMON and GEPHYRIN, using immunohistochemical methods to localize the CIN protein in Drosophila embryos. Most of the CIN protein, like GEPHYRIN in the rat CNS, is localized to the cell borders and shows a tissue-specific pattern of expression. In a parallel study, antibody to GEPHYRIN revealed the same tissue-specific expression pattern in fly embryos. Both antibodies show altered staining patterns in cin mutants. Taken together, these results suggest that GEPHYRIN may also carry out a MoCF-related function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380050010
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    HeT-A telomere-specific retrotransposons in the centric heterochromatin of Drosophila melanogaster chromosome 3 (1999)
    Springer
    Molecular genetics and genomics 262 (1999), S. 618-622 
    Details
    ISSN: 1617-4623
    Keywords: Key words Telomeric retrotransposons ; HeT-A elements ; Centric heterochromatin ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have isolated two yeast artificial chromosome (YAC) clones from Drosophila melanogaster that contain a small amount of dodeca satellite (a satellite DNA located in the centromeric region of chromosome 3) and sequences homologous to the telomeric retrotransposon HeT-A. Using these YACs as probes for fluorescence in situ hybridization to mitotic chromosomes, we have localized these HeT-A elements to the centric heterochromatin of chromosome 3, at region h55. The possible origin of these telomeric elements in a centromeric position is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380051124
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Pre-exposure affects the olfactory response of Drosophila melanogaster to menthol (1999)
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 175-181 
    Details
    ISSN: 1570-7458
    Keywords: Olfactory response ; Drosophila ; menthol ; bioassay ; trap assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A modification of the trap assay (Woodard et al., 1989) was used to evaluate the response of Drosophila melanogaster (Meigen) to food media containing menthol. Dose-response curves for flies to mentholic foods were produced for flies that had been pre-exposed to menthol, during development and adult life, and flies that had not been exposed to menthol before the assay. Mentholic food media were less attractive to Drosophila than plain food medium. Rearing flies on a medium containing menthol reduced their aversion to some concentrations of menthol. The rearing effect was not simply due to lowered general activity levels resulting from developing in a medium containing menthol. There was a threshold concentration of menthol in the rearing medium below which we found no induced behavioural change.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003509802181
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Microspatial genetic differentiation for tolerance and utilization of various alcohols and acetic acid in Drosophila species from India (1999)
    Springer
    Genetica 105 (1999), S. 249-258 
    Details
    ISSN: 1573-6857
    Keywords: alcoholic resources ; Drosophila ; habitat selection ; Indian subcontinent ; short range variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In five Indian localities, it was possible to collect D. melanogaster in two different types of habitats, namely ordinary domestic and alcohol rich ones. Tolerance and utilization capacity of several alcohols and of acetic acid were analyzed in a total of 10 local populations. Results on two other species (D. repleta and D. immigrans) were also available from one place. In each locality, the population from alcohol rich habitat proved to be more tolerant to all the investigated products and also to be more capable of using them as a resource. Alcohols toxicity increased with increasing carbon chain length and secondary alcohols were more toxic than primary ones. Utilization capacity of all products was relatively independent of their toxicity. Especially acetic acid, the toxicity of which was low and similar to that of ethanol, was always a fairly poor resource. From a genetic point of view, tolerance and utilization capacity appeared as two relatively independent traits. Natural selection, which is responsible for the genetic differentiation of local populations, is likely to act simultaneously on both traits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003815626258
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Genomic P elements and P-M characteristics of eastern Australian populations of Drosophila melanogaster (1999)
    Springer
    Genetica 106 (1999), S. 231-245 
    Details
    ISSN: 1573-6857
    Keywords: P element ; repressor ; maternal effect ; Drosophila ; population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract As part of our effort to monitor changes in the clinal pattern of P element-associated traits in eastern Australian Drosophila melanogaster, we investigated the genomic P elements of 293 isofemale lines collected in the period 1991–1994 from 45 localities. P elements were present in many copies in all genomes examined, with full-size P and KP element size classes accounting for the large majority. SR elements were not present in at least 92% of the lines tested. South of about 26° south Latitude (°SLat), the ratio of KP to full-size P elements (KP/P ratio) increased, correlating weakly with the P-M phenotypes of the populations, from moderately P populations (26–29°SLat) to M populations (37–38°SLat) North of 26°SLat, in weak P populations, the KP/P ratio was higher than between 26 and 29°Slat. The KP/P ratio appears to be higher in the northern populations than it was when previous studies were done. Overall, a high KP/P ratio among lines correlated roughly with a lack of P activity, but it also correlated with reduced repressor function. In a sample of 30 lines, a maternal effect of repressor function did not show a pattern with latitude, nor with KP/P ratio, nor with presence or absence of P activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003918417012
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    How valuable are model organisms for transposable element studies? (1999)
    Springer
    Genetica 107 (1999), S. 103-111 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; genome evolution ; model organisms ; transposons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Model organisms have proved to be highly informative for many types of genetic studies involving ‘conventional’ genes. The results have often been successfully generalized to other closely related organisms and also, perhaps surprisingly frequently, to more distantly related organisms. Because of the wealth of previous knowledge and their availability and convenience, model organisms were often the species of choice for many of the earlier studies of transposable elements. The question arises whether the results of genetic studies of transposable elements in model organisms can be extrapolated in the same ways as those of conventional genes? A number of observations suggest that special care needs to be taken in generalizing the results from model organisms to other species. A hallmark of many transposable elements is their ability to amplify rapidly in species genomes. Rapid spread of a newly invaded element throughout a species range has also been demonstrated. The types and genomic copy numbers of transposable elements have been shown to differ greatly between some closely related species. Horizontal transfer of transposable elements appears to be more frequent than for nonmobile genes. Furthermore, the population structure of some model organisms has been subject to drastic recent changes that may have some bearing on their transposable element genomic complements. In order to initiate discussion of this question, several case studies of transposable elements in well-studied Drosophila species are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003933419159
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Evidence for genomic regulation of the telomeric activity in Drosophila melanogaster (1999)
    Springer
    Genetica 107 (1999), S. 95-102 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; genomic regulation ; telomeric activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The structural integrity of TART elements has been used as reporter of instability at chromosomal ends in numerous Drosophila stocks and over time in an unstable stock. The results show that telomeric activity is a regulated process that may differ between the stocks as well as over time within a stock.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003911925791
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Molecular domestication – more than a sporadic episode in evolution (1999)
    Springer
    Genetica 107 (1999), S. 197-207 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; genome evolution ; molecular domestication ; P element ; transposable elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transposable elements are short but complex pieces of DNA or RNA containing a streamlined minimal-genome with the capacity for its selfish replication in a foreign genomic environment. Cis-regulatory sections within the elements orchestrate tempo and mode of TE expression. Proteins encoded by TEs mainly direct their own propagation within the genome by recruitment of host-encoded factors. On the other hand, TE-encoded proteins harbor a very attractive repertoire of functional abilities for a cell. These proteins mediate excision, replication and integration of defined DNA fragments. Furthermore, some of these proteins are able to manipulate important host factors by altering their original function. Thus, if the host genome succeeds in domesticating such TE-encoded proteins by taming their ‘anarchistic behavior,’ such an event can be considered as an important evolutionary innovation for its own benefit. In fact, the domestication of TE-derived cis-regulatory modules and protein coding sections took place repeatedly in the course of genome evolution. We will present prominent cases that impressively demonstrate the beneficial impact of TEs on host biology over evolutionary time. Furthermore, we will propose that molecular domestication might be considered as a resumption of the same evolutionary process that drove the transition from ‘primitive genomes’ to ‘modern’ ones at the early dawn of life, that is, the adaptive integration of a short piece of autonomous DNA into a complex regulatory network.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004070603792
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Size and shape heritability in natural populations of Drosophila mediopunctata: temporal and microgeographical variation (1999)
    Springer
    Genetica 105 (1999), S. 35-42 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; heritability ; principal component analysis ; shape ; size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract ‘Traditional morphometrics’ allows us to decompose morphological variation into its major independent sources, identifying them usually as size and shape. To compare and investigate the properties of size and shape in natural populations of Drosophila mediopunctata, estimating their heritabilities and analysing their temporal and microgeographic changes, we carried out collections on seven occasions in Parque Nacional do Itatiaia, Brazil. In one of these collections, we took samples from five different altitudes. Measurements were taken from wild caught inseminated females and up to three of their laboratory‐reared daughters. Through a principal component analysis, three major sources of variation were identified as due to size (the first one) and shape (the remaining two). The overall amount of variation among laboratory flies was about half of that observed among wild flies and this reduction was primarily due to size. Shape variation was about the same under natural and artificial conditions. A genetic altitudinal cline was detected for size and shape, although altitude explained only a small part of their variation. Differences among collections were detected both for size and shape in wild and laboratory flies, but no simple pattern emerged. Shape variation had high heritability in nature, close to or above 40% and did not vary significantly temporally. Although on the overall size heritability (18 ± 6%)was significant its estimates were not consistent along months – they were non‐significant in all but one month, when it reached a value of 51 ± 11%. Overall, this suggests that size and shape have different genetic properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003591726851
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Structural instability of 297 element in Drosophila melanogaster (1999)
    Springer
    Genetica 105 (1999), S. 239-248 
    Details
    ISSN: 1573-6857
    Keywords: transposable elements ; LTR-retroelements ; rearrangements ; population genetics ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 297 element Southern pattern modifications previously detected in mutation accumulation lines of Drosophila melanogaster were further investigated by in situ hybridisation, Southern blotting with different combinations of genomic digest-probe, and PCR. Only one out of the nine pattern modifications studied could be interpreted as an excision and was detectable by in situ hybridisation to polytene chromosomes. Results were consistent with most pattern modifications being small rearrangements within the body of the element. In agreement with the existence of spontaneous rearrangements of this kind is the observation that many genomic copies of element 297 are defective and these are not limited to heterochromatin. These findings have important implications for the models of transposable element (TE) number regulation as well as for the study of genome evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003957606743
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Transposable elements and genome evolution: the case of Drosophila simulans (1999)
    Springer
    Genetica 107 (1999), S. 113-120 
    Details
    ISSN: 1573-6857
    Keywords: colonization ; Drosophila ; dynamic ; natural populations ; transposable elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Drosophila simulans presents a large variation in copy number among various transposable elements (TEs) and among natural populations for a given element. Some elements such as HMS beagle, blood, flea, tirant, coral, prygun jockey, F, nomade and mariner are absent in most populations, except in one or two which have copies on their chromosome arms. This suggests that some TEs are being awakened in D. simulans and are in the process of invading the species while it is colonizing the world. The elements 412 and roo/B104 present a wide insertion polymorphism among D. simulans populations, but only the 412 copy number follows a temperature cline. One population (Canberra from Australia) has a very high copy number for the 412 element and for many other TEs as well, indicating that some populations may have lost control of some of their TEs. While the 412 transposition rate is similar in all populations, its transcription level throughout developmental stages varies with populations, depending on copy number. Populations with 412 copy number higher than 10–12 exhibit co-suppression, while the expression in populations with lower numbers depends on the insertion location. All these results suggest genomic invasions by 412 and other TEs during the worldwide spread of the D. simulans species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003937603230
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    A Simple Cytological Technique to Analyze Nuclear Divisions During Preblastodermic Development in Drosophila (1999)
    Springer
    Chromosome research 7 (1999), S. 445-448 
    Details
    ISSN: 1573-6849
    Keywords: chromosomes ; cytological technique ; Drosophila ; embryos ; mitosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009245712709
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    TTAGG Telomeric Repeats in Chromosomes of Some Insects and Other Arthropods (1999)
    Springer
    Chromosome research 7 (1999), S. 449-460 
    Details
    ISSN: 1573-6849
    Keywords: Apis ; Bombyx ; Drosophila ; Ephestia ; fluorescence in-situ hybridization (FISH) ; Galleria ; Gammarus ; insect phylogeny ; Ips ; Locusta ; Megaselia ; Pyrrhocoris ; Southern hybridization ; Tegenaria ; telomere ; Tenebrio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied the occurrence of the TTAGG telomere repeats by fluorescence in-situ hybridization (FISH) and Southern hybridization in ten insect species and two other arthropods. (TTAGG)n-containing telomeres were found in three Lepidoptera species, the silkworm Bombyx mori (in which the telomeric sequence was recently discovered), the flour moth Ephestia kuehniella, and the wax moth Galleria mellonella, in one species of Hymenoptera, the honey bee Apis mellifera, in one species of Coleoptera, the bark beetle Ips typographus, in one species of Orthoptera, the locust Locusta migratoria, and in a crustacean, the amphipod Gammarus pulex. They were absent in another species of Coleoptera, the mealworm Tenebrio molitor, two representatives of Diptera, Drosophila melanogaster and Megaselia scalaris, a species of Heteroptera, the bug Pyrrhocoris apterus and a spider, Tegenaria ferruginea. Our results, which confirm and extend earlier observations, suggest that (TTAGG)n was a phylogenetically ancestral telomere motif in the insect lineage but was lost independently in different groups, being replaced probably by other telomere motifs. In the Coleoptera this must have happened rather recently as even members of the same family, Curculionidae, differ with respect to the telomeric DNA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009297729547
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Does evolution reduce the body size? A study of the four members of newly evolved nasuta‐albomicans complex of Drosophila (1999)
    Springer
    Genetica 105 (1999), S. 1-6 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; nasuta-albomicans ; complex ; cytoraces ; body size ; fertility ; ovariole number ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Our long range interracial hybridization experiments between a pair of cross fertile races, Drosophila nasuta (2n = 8) and D.albomicans (2n = 6) have resulted in the evolution of two new karyotypic strains under laboratory conditions, which are named as Cytorace 1 and Cytorace 2. These Cytoraces harbor chromosomes from both parents. Here, we compare the body size of the parental races and newly evolved Cytoraces and the relationship between the body size and fitness. Analysis reveals that the parental races have reduced fertility and are larger in body size than newly evolved Cytoraces. Thus, the newly evolved Cytoraces show reduced body size and better fitness in the course of their evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003762826116
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Integration specificity of the hobo element of Drosophila melanogaster is dependent on sequences flanking the integration site (1999)
    Springer
    Genetica 105 (1999), S. 133-147 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; hobo ; hot spot ; integration specificity ; transposable elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We analyzed the integration specificity of the hobo transposable element of Drosophila melanogaster. Our results indicate that hobo is similar to other transposable elements in that it can integrate into a large number of sites, but that some sites are preferred over others, with a few sites acting as integration hot spots. A comparison of DNA sequences from 112 hobo integration sites identified a consensus sequence of NTNNNNAC, but this consensus was insufficient to account for the observed integration specificity. To begin to define the parameters affecting hobo integration preferences, we analyzed sequences flanking a donor hobo element, as well as sequences flanking a hobo integration hot spot for their relative influence on hobo integration specificity. We demonstrate experimentally that sequences flanking a hobo donor element do not influence subsequent integration site preference, whereas, sequences contained within 31 base pairs flanking an integration hot spot have a significant effect on the frequency of integration into that site. However, sequence analysis of the DNA flanking several hot spots failed to identify any common sequence motif shared by these sites. This lack of primary sequence information suggests that higher order DNA structural characteristics of the DNA and/or chromatin may influence integration site selection by the hobo element.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003712619487
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Distribution of transposable elements in Drosophila species (1999)
    Springer
    Genetica 105 (1999), S. 43-62 
    Details
    ISSN: 1573-6857
    Keywords: distribution ; Drosophila ; retrotransposon ; transposable element
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We present a global analysis of the distribution of 43 transposable elements (TEs) in 228 species of the Drosophila genus from our data and data from the literature. Data on chromosome localization come from in situ hybridization and presence/absence of the elements from southern analyses. This analysis shows great differences between TE distributions, even among closely related species. Some TEs are distributed according to the phylogeny of their host specie; others do not entirely follow the phylogeny, suggesting horizontal transfers. A higher number of insertion sites for most TEs in the genome of D. melanogaster is observed when compared with that in D. simulans. This suggests either intrinsic differences in genomic characteristics between the two species, or the influence of differing effective population sizes, although biases due to the use of TE probes coming mostly from D. melanogaster and to the way TEs are initially detected in species cannot be ruled out. Data on TEs more specific to the species under consideration are necessary for a better understanding of their distribution in organisms and populations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003718520490
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Response of Djun and Dfos mRNA abundance to signal transduction pathways in cultured cells of Drosophila melanogaster (1999)
    Springer
    Molecular biology reports 26 (1999), S. 147-157 
    Details
    ISSN: 1573-4978
    Keywords: Drosophila ; jun ; fos ; AP-1 ; transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mammalian proto-oncogenes c-jun and c-fos are situated at the end of multiple signal transduction pathways and activation of their products Jun and Fos, components of the transcription factor AP-1, are able to regulate gene transcription in response to extracellular stimuli. Djun and Dfos, the products of the Drosophila proto-oncongenes Djun and Dfos, are similar in size and sequence to their mammalian counterparts c-Jun and c-Fos and are related to their mammalian counterparts by their antigenic properties. However, very little is known about how they are regulated through signal transduction pathways. This paper has investigated the response of their mRNA abundance levels to three signal transduction pathways in Drosophila cultured cells. Various agonists and anagonists that stimulate and inhibit specific enzymes in the pathways have been tested. The results suggest that Djun and Dfos mRNA are continuously expressed and their abundance levels are transiently regulated by multiple signaling pathways, the peak response coming at 1–2 hours after perturbation. Dfos is more highly regulated than Djun which is only modulated. The receptor tyrosine kinase pathways positively regulate Dfos and Djun. The cAMP-mediated pathway positively regulates Dfos but negatively regulates Djun. The protein kinase C-activated pathway does not affect Djun whereas it negatively regulates Dfos.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006906419110
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Structure and functions of arthropod proteasomes (1999)
    Springer
    Molecular biology reports 26 (1999), S. 103-111 
    Details
    ISSN: 1573-4978
    Keywords: arthropod ; crustacean ; Drosophila ; insect ; lobster ; multicatalyic proteinase ; proteasome ; ubiquitin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recent work on structural/functional relationships in arthropod proteasomes is reviewed. Taking advantage of our ability to induce a stable, proteolytically-active conformation of the lobster proteasome, the structures of basal and heat-activated complexes were probed with exogenous proteases. Increased sensitivity to chymotrypsin and trypsin showed that heat activation induced a more ‘open’ conformation, allowing entry of large substrates into the catalytic chamber. In Drosophila, the effects of two developmental mutant alleles (DTS-7 and DTS-5) encoding proteasome subunits (Z and C5, respectively) on the subunit composition and catalytic activities of the enzyme were examined. Both qualitative and quantitative differences in compositions between wild-type (+/+) and heterozygotes (+/DTS) indicated that incorporation of mutant subunits alters post-translational modifications of the complex. Catalytic activities, however, were similar, which suggests that the developmental defect involves other proteasome properties, such as intracellular localization and/or interactions with endogenous regulators. A hypothetical model in which DTS subunits act as poison subunits is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006976524916
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Developmental Isolation and Subsequent Adult Behavior of Drosophila paulistorum. V. Survey of Six Sibling Species (1999)
    Springer
    Behavior genetics 29 (1999), S. 65-73 
    Details
    ISSN: 1573-3297
    Keywords: Mating behavior ; reproductive isolation ; sexual isolation ; sibling species ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract In an investigation into the effects of developmental isolation from all conspecifics, the Drosophila willistoni group of six sibling species responded to differing degrees: all six are reproductively isolated from D. paulistorum, the tester species. Drosophila pavlovskiana, a narrow endemic, proved the most vulnerable, responding by reducing its adult sexual isolation, if eggs, any instar, and sometimes even pupae were socially isolated. To lesser degrees, D. tropicalis and D. willistoni both produced similar results only when their eggs were isolated, i.e., when from the moment of egg deposition on, there was absolutely no contact with other flies until testing for mating behavior. The remaining siblings, D. equinoxialis and D. insularis, were immovable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021494023660
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Oviposition-Site Preference in Drosophila Following Interspecific Gene Transfer of the Alcohol dehydrogenase Locus (1999)
    Springer
    Behavior genetics 29 (1999), S. 199-204 
    Details
    ISSN: 1573-3297
    Keywords: Drosophila ; oviposition-site preference ; alcohol dehydrogenase ; transgene coplacement ; ethanol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract The preference of Drosophila females to lay eggs on substrates that do or do not contain alcohol is an excellent system to study the evolutionary genetics of behavior, because (1) there is variation in this behavior within and among species, (2) the behavior is amenable to laboratory investigation, and (3) the behavior presumably has a direct relationship to reproductive fitness. Moreover, a key genetic component of the system, the Alcohol dehydrogenase (Adh) locus, is arguably the most well characterized gene known. However, because the Adh gene and its genetic background are inseparable in reproductively isolated species, it is difficult to establish its role in behavioral divergence. By transgene coplacement, we created pairs of strains of D. melanogaster expressing an Adh allele from either D. melanogaster or D. affinidisjuncta, a Hawaiian species with very low levels of ADH in adults. When raised on ethanol-containing medium, the affinidisjuncta–Adh strains experience high mortality relative to the melanogaster–Adh strains. However, affinidisjuncta–Adh females show the same preference for oviposition on ethanol-containing medium as melanogaster–Adh females. Thus, preference for ethanol in these strains is not determined primarily by Adh genotype.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021648103496
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Caveolin and its cellular and subcellular immunolocalisation in lung alveolar epithelium: implications for alveolar epithelial type I cell function (1999)
    Springer
    Cell & tissue research 295 (1999), S. 111-120 
    Details
    ISSN: 1432-0878
    Keywords: Key words Caveolin ; Caveolae ; Lung ; Alveolar epithelial type I cell ; Immunocytochemistry ; Electron microscopy ; Confocal laser scanning microscopy ; Rat (CD)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Caveolae are flask-shaped invaginations of the plasmalemma which pinch off to form discrete vesicles within the cell cytoplasm. Biochemically, caveolae may be distinguished by the presence of a protein, caveolin, that is the principal component of filaments constituting their striated cytoplasmic coat. Squamous alveolar epithelial type I (ATI) cells, comprising approximately 95% of the surface area of lung alveolar epithelium, possess numerous plasmalemmal invaginations and cytoplasmic vesicles ultrastructurally indicative of caveolae. However, an ultrastructural appearance does not universally imply the biochemical presence of caveolin. This immunocytochemical study has utilised a novel application of confocal laser scanning and electron microscopy unequivocally to localise caveolin-1 to ATI cells. Further, cytoplasmic vesicles and flask-shaped membrane invaginations in the ATI cell were morphologically identified whose membranes were decorated with anti-caveolin-1 immunogold label. Coexistent with this, however, in both ATI and capillary endothelial cells could be seen membrane invaginations morphologically characteristic of caveolae, but which lacked associated caveolin immunogold label. This could reflect a true biochemical heterogeneity in populations of morphologically similar plasmalemmal invaginations or an antigen threshold requirement for labelling. The cuboidal alveolar epithelial type II cell (ATII) also displayed specific label for caveolin-1 but with no ultrastructural evidence for the formation of caveolae. The biochemical association of caveolin with ATI cell vesicles has broad implications for the assignment and further study of ATI cell function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051217
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Periviscerokinin-like immunoreactivity in the nervous system of the American cockroach (1999)
    Springer
    Cell & tissue research 295 (1999), S. 159-170 
    Details
    ISSN: 1432-0878
    Keywords: Key words Neuropeptides ; Perisympathetic organ ; Myotropin ; Visceral muscles ; Immunocytochemistry ; Insect nervous system ; Periplaneta americana (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A highly specific polyclonal antiserum has been raised against periviscerokinin, the first neuropeptide isolated from the perisympathetic organs of insects (Predel et al. 1995). In this study, two different neuronal systems with periviscerokinin-like immunoreactivity were distinguished in the central nervous system of the American cockroach: (1) An intrinsic neuronal network, restricted to the head-thoracic region, was formed by intersegmental projecting neurons of the brain, suboesophageal ganglion and metathoracic ganglion. In addition, groups of local interneurons occurred in the proto- and tritocerebrum. (2) A typical neurohormonal system was stained exclusively in the abdomen; it was represented by abdominal perisympathetic organs which were supplied by three cell clusters located in each unfused abdominal ganglion. As revealed by nickel backfills, most neurons with axons entering the perisympathetic organs contained a periviscerokinin-like peptide. Immunoreactive fibres left the perisympathetic organs peripherally, innervated the hyperneural muscle and ran via the link nerves/segmental nerves to the heart and segmental vessels. All visceral muscles innervated by periviscerokinin-immunoreactive fibres were shown to be sensitive to periviscerokinin, whereas the hindgut gave no specific response to this peptide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051222
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Morphology and synaptic connectivity of nitric oxide synthase-immunoreactive neurons in the guinea pig retina (1999)
    Springer
    Cell & tissue research 297 (1999), S. 397-408 
    Details
    ISSN: 1432-0878
    Keywords: Key words Retina ; NOS ; Immunocytochemistry ; Synaptic connectivity ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Immunocytochemical methods with an antiserum against neuronal nitric oxide synthase (NOS) were applied to identify the morphology and synaptic connectivity of NOS-like immunoreactive neurons in the guinea pig retina. In the present study, two types of amacrine cells were labeled with anti-NOS antisera. Type 1 cells had large somata located in the inner nuclear layer (INL) with long, sparsely branched processes ramifying mainly in stratum 3 of the inner plexiform layer (IPL). The somata of type 2 cells (smaller diameters) were located in the INL. Some displaced amacrine cells in the ganglion cell layer were labeled. The soma size of the displaced amacrine cells was similar to that of the type 2 amacrine cells. However, processes originating from type 2 amacrine cells and displaced amacrine cells stratified mainly in strata 1 and 5, respectively. Some cone bipolar cells were weakly NOS-immunoreactive. The synaptic connectivity of NOS-like immunoreactive amacrine cells was identified in the IPL by electron microscopy. NOS-labeled amacrine cell processes received synaptic input from other amacrine cell processes and bipolar cell axon terminals in all strata of the IPL. The most frequent postsynaptic targets of NOS-immunoreactive amacrine cells were other amacrine cell processes. Cone bipolar cells were postsynaptic to NOS-labeled amacrine cells in all strata of the IPL. Labeled amacrine cells synapsing onto ganglion cells were found only in sublamina b. A few synaptic contacts were observed between labeled cell processes. In the outer plexiform layer, dendrites of labeled bipolar cells made basal contact with cone pedicles or formed a synaptic triad opposed to a synaptic ribbon of cone pedicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051367
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Pigment-dispersing hormone-like immunoreactive neurons in the central nervous system of the gastropods, Helix pomatia and Lymnaea stagnalis (1999)
    Springer
    Cell & tissue research 295 (1999), S. 339-348 
    Details
    ISSN: 1432-0878
    Keywords: Key words Pigment-dispersing hormone ; Immunocytochemistry ; Central nervous system ; Gastropoda ; Helix pomatia ; Lymnaea stagnalis (Mollusca)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract By using an antiserum raised against a crustacean β-pigment-dispersing hormone (PDH), the distribution and chemical neuroanatomy of PDH-like immunoreactive neurons was investigated in the central nervous system of the gastropod snails, Helix pomatia and Lymnaea stagnalis. The number of immunoreactive cells in the Helix central nervous system was found to be large (700–900), whereas in Lymnaea, only a limited number (50–60) of neurons showed immunoreactivity. The immunostained neurons in Helix were characterized by rich arborizations in all central ganglia and revealed massive innervation of all peripheral nerves and the neural (connective tissue) sheath around the ganglia and peripheral nerve trunks. A small number of Helix nerve cell bodies in the viscero-parietal ganglion complex were also found to be innervated by PDH-like immunoreactive processes. Hence, a complex central and peripheral regulatory role, including neurohormonal actions, is suggested for a PDH-like substance in Helix, whereas the sites of action may be more limited in Lymnaea.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051240
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Simultaneous apocrine and merocrine secretion in the rat coagulating gland (1999)
    Springer
    Cell & tissue research 295 (1999), S. 495-504 
    Details
    ISSN: 1432-0878
    Keywords: Key words Coagulating gland ; Apocrine secretion ; Merocrine secretion ; Immunocytochemistry ; Immunoelectron microscopy ; Scanning electron microscopy ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The coagulating gland of the rat synthesizes two prevalent secretory proteins (transglutaminase and 115 K) that are discharched in a different manner, one being secreted in an apocrine fashion (transglutaminase) and the other one in a merocrine way (115 K). Differences in the intra- cellular pathway and the release of either protein were studied using immunofluorescence on semithin sections, immunoelectron microscopy of preembedding-processed chopper sections and postembedding-processed ultrathin sections of rat coagulating gland. Immunohistochemical staining using an anti-transglutaminase antibody resulted in dense labeling of the cytoplasm of secretory cells and their apical blebs, whereas the cisternae of the rough endoplasmic reticulum and the Golgi apparatus were completely unlabeled. When, on the contrary, the anti-115 K antiserum was used, dense labeling of the cisternae of the rough endoplasmic reticulum, the Golgi apparatus, and the secretory granules was seen. Intraluminal secretion was also labeled, but the secretory blebs remained unlabeled. Our findings show that, in the coagulating gland of the male rat, the two secretory proteins studied are processed in parallel, but at completely different intracellular pathways. They are released via different extrusion mechanisms. Transglutaminase is synthesized outside the endoplasmic reticulum, reaches the apical cell pole by free flow in the cytoplasm, and is released via apocrine blebs, the membranes of which appear to be derived from the apical plasma membrane. The protein 115 K, on the other hand, follows the classic route, being synthesized within the cisternae of rough endoplasmic reticulum, subsequently glycosylated in the Golgi apparatus, and released in a merocrine fashion. The mutual exclusion of the two secretory pathways and the regulation of the alternative release mechanism are still unresolved issues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051255
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Immunoultrastructural expression of intercellular adhesion molecule-1 in endothelial cell vesiculotubular structures and vesiculovacuolar organelles in blood-brain barrier development and injury (1999)
    Springer
    Cell & tissue research 295 (1999), S. 77-88 
    Details
    ISSN: 1432-0878
    Keywords: Key words Cerebrovascular development and injury ; Hemangioma ; Angiogenesis ; Immunocytochemistry ; Adhesion molecules ; Conventional transmission and high-voltage electron microscopy ; Mouse (C57BL ; SJL/J) ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Blood vessels from the vasculature of mouse brains during postnatal development and from human brain tumors (hemangiomas) removed at biopsy were examined immunocytochemically by transmission electron microscopy (TEM) or high-voltage transmission electron microscopy (HVEM) to determine the expression of intercellular adhesion molecule-1 (ICAM-1). In the mouse brains, ICAM-1 was shown to be initially expressed on the luminal and abluminal endothelial cell (EC) surfaces on day 3 after birth. ICAM-1 intensity increased on the luminal EC surfaces and labeled vesiculotubular profiles (VTS, defined in the present report) between days 5 and 7. After 2 weeks and at 6 months after birth, ICAM-1 labeling was weak or absent on the luminal EC surfaces. The hemangiomas presented a strong ICAM-1 reaction product on the luminal EC surfaces of small and large blood vessels associated with the VTS, with a weaker labeling of the abluminal or adventitial aspects of larger blood vessels. TEM of vesiculovacuolar structures (VVOs) within ECs from arteries and veins also demonstrated reaction product for ICAM-1 labeling. Three-dimensional stereo-pair images in the HVEM enhanced the visualization of gold particles that were attached to the inner-delimiting membrane surfaces of EC VTS, and VVOs, respectively. These observations raise the possibility that the neonatal leukocytes and tumor cells may utilize these endothelial structures as a route across the developing and injured blood-brain barrier (BBB).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051214
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Survival of rat MCH (melanin-concentrating hormone) neurons in hypothalamus slice culture: histological, pharmacological and molecular studies (1999)
    Springer
    Cell & tissue research 297 (1999), S. 23-33 
    Details
    ISSN: 1432-0878
    Keywords: Key words Melanin-concentrating hormone neurons ; Lateral hypothalamic slice culture ; Immunocytochemistry ; Ultrastructure ; In situ hybridization ; Competitive RT-PCR ; Leptin assay ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Hypothalamic slices containing the lateral hypothalamic area (LHA) were prepared from 6- to 8-day-old rats and maintained in stationary culture for up to 35 days in order to analyse how well the melanin-concentrating hormone (MCH) neurons survived. As previously reported for other brain areas, this method yielded a long-term well-preserved organotypic organization. Light- and electron-microscopic investigations showed that differentiation continued and that synaptic contacts developed in vitro. After a period of elimination of damaged cells and fibres, most of the remaining neurons and glial cells retained a normal morphology throughout the culture period. MCH neurons, in particular, survived well as attested by the strong immunocytochemical and in situ hybridization signals still observed after several weeks. In a comparison with the day of explantation, competitive reverse transcription/polymerase chain reaction demonstrated the remarkable stability of the level of MCH mRNA at least until the 20th day in culture; after 30 days, the clear decrease in this level seemed to be correlated with a loss of MCH neurons, rather than with a decrease in MCH expression. After 10 days of culture, the incubation of slices in the presence of the hormone leptin (50 ng/ml) resulted in a strong decrease of MCH gene expression, suggesting that MCH neurons retained their physiological properties. Thus, the LHA slice stationary culture, especially between one and three weeks (i.e. after tissue stabilization and before extensive cell loss), appears to be a suitable method for physiological and pharmacological studies of these neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051330
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Two non-linked genes for specific virulence of Leptopilina boulardi against Drosophila melanogaster and D. yakuba (1999)
    Springer
    Evolutionary ecology 13 (1999), S. 211-220 
    Details
    ISSN: 1573-8477
    Keywords: Drosophila ; evolutionary genetics ; host specificity ; parasitoid ; virulence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The developmental success of Leptopilina boulardi parasitoids within host species of the melanogaster subgroup is determined mainly by their ability to suppress the host immune reaction (virulence). Host resistance and parasitoid virulence are genetically variable in both partners. A gene for specific resistance against L. boulardi (Rlb) has been identified in Drosophila melanogaster, and a gene for the immune suppression (IS) of D. melanogaster has been identified in L. boulardi. To understand the evolution of the IS gene, we determined its specificity regarding potential hosts of the melanogaster subgroup. It did not affect the virulence against any other species of the melanogaster subgroup and was called ISm for immune suppression of D. melanogaster. Another gene (ISy), non-linked to the gene ISm, was characterized for the specific immune suppression of D. yakuba. These results suggesting that natural selection for virulence against one host species does not influence the evolution of virulence against another will allow us to develop pertinent hypotheses concerning the evolution of this character which is expected to drive the evolution of the parasitoid toward narrow host specialization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006691431658
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Structure and function of the human oocyte-cumulus-corona cell complex before and after ovulation (1999)
    Springer
    Protoplasma 206 (1999), S. 270-277 
    Details
    ISSN: 1615-6102
    Keywords: Cumulus oophorus ; Ovarian follicle ; Fertilization ; Ultrastructure ; Immunocytochemistry ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The fine structure of the human cumulus oophorus has been reviewed on the basis of scanning and transmission electron microscopic observations as well as of immunofluorescence data. Tissues sampled from preovulatory ovarian follicles and cumulus-enclosed oocytes and fertilized eggs (collected from the oviduct or obtained during in vitro fertilization procedures) have been evaluated from a microtopographic and morphodynamic point of view in order to better clarify the possible role of this population of cells. In particular, the following aspects have been studied and discussed: the presence of multiple close contacts (modulated by the interposition of the zona pellucida) between the oocyte surface and the long microvillous evaginations projecting from the inner aspect of corona cells surface (through these structures the intraovarian cumulus oophorus may control oocyte growth and metabolism up until the time of ovulation); the occurrence of different subpopulations of cells (steroid-synthetic cells, cells producing adhesive proteins, leukocytes, macrophages) in the postovulatory, extraovarian cumulus oophorus surrounding oocytes, zygotes and early developing embryos. All these elements found in the cumulus mass may positively act, through their paracrine activities, on the chemical composition of the microenvironment in which fertilization occurs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01288215
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Immunolocalization of the petunia floral binding proteins 7 and 11 during seed development in wild-type and expression mutants ofPetunia hybrida (1999)
    Springer
    Protoplasma 208 (1999), S. 224-229 
    Details
    ISSN: 1615-6102
    Keywords: Floral binding protein ; Flower development ; Immunocytochemistry ; MADS-box genes ; Ovule ; Transcription factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary DuringPetunia hybrida seed development, the MADS-box genes encoding the floral binding proteins (FBP) 7 and 11 are expressed in the seed coat and not in the endosperm or embryo. These proteins are thought to function as transcription factors and are essential for ovule formation inPetunia spp. Immunocytochemical methods were used to analyze the distribution of FBP7 and FBP11 after fertilization in wild type and ectopic and cosuppression mutants. During the first nine days of seed development the protein was found in the nuclei of seed coat cells, of both wild-type plants and plants which ectopically expressedFBP11. The signal for FBP7 and -11 proteins diminished during seed development, was first lost in the outer epidermis of the seed coat, then in the endothelium, and finally, at 9 days after pollination (DAP), the protein could not be detected anymore in the parenchyma cells of the seed coat. Although the distribution patterns in wild-type andFBP11 ectopically expressing plants are similar, the latter exhibited higher protein levels. A mild-cosuppression mutant ofFBP7 andFBP11, having only a total of 5%FBP7 and -11 mRNA, showed hardly any FBP7 and -11 proteins. The lack of FBP7 and -11 caused endosperm degeneration in the mutant at a moment when the protein had already decreased to an undetectable level in the wild type and ectopic expression mutant (i.e., at 13 DAP). It is suggested that till about 9 DAP a minimal amount of FBP7 and -11 is needed for the normal functioning of the seed coat during later stages, i.e., for transfer of nutrients to endosperm and embryo. Besides the immunocytochemical data on theFBP7 andFBP11 MADS-box gene products, the morphological analysis of wild type and mutants contributes details on early seed development inPetunia hybrida.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279093
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Interface between haustoria of parasitic members of the Scrophulariaceae and their hosts: A histochemical and immunocytochemical approach (1999)
    Springer
    Protoplasma 207 (1999), S. 84-97 
    Details
    ISSN: 1615-6102
    Keywords: Haustorium ; Immunocytochemistry ; Interface ; Parasitism ; Defense mechanisms ; Scrophulariaceae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The haustorial structure of three African parasitic members of the family Scrophulariaceae (Buchnera hispida, Rhamphicarpa fistulosa, andStriga hermonthica) has been studied with regard to the interface between haustoria and the invaded host roots. Immunocytochemical observations at the light and electron microscopical level were carried out with monoclonal antibodies against pectin. JIM5, JIM7, and hydroxyproline-rich glycoprotein (HRGP), LM1. Lignins have been visualized by phloroglucinolhydrochloric acid staining. At the margin of the lateral interface (contact area of host root cortex and parasite cells), JIM5- and JIM7-labelled substances accumulate between parasite papillae and the host root surface indicating that pectins are implicated in sealing the parasite to the attacked host organ. The lateral interface is characterized by the presence of compressed, necrotic host cells, whereas the central interface (contact area between host stele and parasite cells) is generally devoid of host cell remnants. Phenolic substances and/or lignins can be found at the site of penetration of the haustorium into the host root. These observations and the fact that HRGPs accumulate at the host side of the interface support the view of, at least, a partial defense reaction in the invaded host root tissues. Within haustoria, HRGPs were restricted to differentiating xylem elements, implying a spatio-temporal regulation of HRGPs in developmental processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01294716
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Immunolocalization of the cell wall components inPinus densiflora pollen (1999)
    Springer
    Protoplasma 206 (1999), S. 1-10 
    Details
    ISSN: 1615-6102
    Keywords: Arabinogalactan protein ; Cell wall component ; Immunocytochemistry ; Pectin ; Pinus densiflora ; Pollen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In order to compare cell wall formation in gymnosperm pollen with that in angiosperm pollen, the distribution of cell wall constituents in the pollen grain and pollen tube ofPinus densiflora was studied immunocytochemically with monoclonal antibodies JIM 5 (against non- or poorly esterified pectin), JIM 7 (against highly esterified pectin), JIM 13 (against arabinogalactan proteins, AGPs), and LM 2 (against AGPs containing glucuronic acid). In the pollen grain wall, only the outer layer of the intine was labeled with JIM 5 and weakly with JIM 7. The tube wall was scarcely labeled with JIM 5 and very weakly labeled with JIM 7. In contrast, the whole of both the intine and the tube wall was strongly labeled with JIM 13 and LM 2, and the generative-cell wall was also labeled only with LM 2. The hemicellulose B fraction, which is the main polysaccharide fraction from the pollen tube wall, reacted strongly with JIM 13 and especially LM 2, but not with antipectin antibodies. These results demonstrate that the wall constituents and their localization inP. densiflora pollen are considerably different from those reported in angiosperm pollen and suggest that the main components of the cell wall ofP. densiflora pollen are arabinogalactan and AGPs containing glucuronic acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279247
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Immunohistochemical evidence of the presence of aromatase P450 in the rat hypophysis (1999)
    Springer
    Cell & tissue research 295 (1999), S. 419-423 
    Details
    ISSN: 1432-0878
    Keywords: Key words Hypophysis ; Aromatase ; Immunocytochemistry ; Morphometry ; Gender differences ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In order to analyze whether aromatase is present in the hypophysis of adult rats, we have performed an immunohistochemical study in young adult male and female rats. Our study has revealed that the hypophysis of adult rats contains aromatase, although marked differences are found between the sexes. The hypophyses of male rats have cells immunoreactive for the enzyme, 34.40% of these hypophyseal cells showing reaction. By contrast, cells from female rats show very little reaction, only 0.84% of them being reactive. No significant differences in the percentage of immunoreactive cells between one phase and another are observed during the estrous cycle. Our results point to the immunohistochemical expression of aromatase in the hypophysis of adult rats and at the same time suggest that its expression is sex-dependent. The enzyme may therefore be involved in the regulation of adenohypophyseal cytology by androgens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051248
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    The expression of histone genes during Drosophila melanogaster oogenesis (1998)
    Springer
    Development genes and evolution 207 (1998), S. 535-541 
    Details
    ISSN: 1432-041X
    Keywords: Key words Histones ; Oogenesis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A genomic fragment was cloned from a DNA library constructed from a Drosophila enhancer trap line in which reporter gene expression was observed at the anterior-most tip of the ovaries and testes. This genomic clone was identified as the L-repeat of the Drosophila melanogaster histone gene cluster. Northern blotting and in situ hybridisation to RNA in tissues with individual cDNAs and PCR-generated probes for each histone confirmed that gene expression was greatest at the anterior portion of each ovariole, in the germarium, and was also elevated in a few individual nurse cells and somatic follicle cells within the egg chamber during early developmental stages. Histone H1 and each of the core histones had a similar expression pattern which was correlated to cell division. Maternal stores of histone transcripts were also transported to the mature oocyte from the nurse cells at a later stage of oogenesis (stage 10), when virtually all the nurse cells contained high levels of histone transcripts. The results are consistent with expression of the somatic histone gene cluster during oogenesis as a co-ordinate unit. There does not seem to be a reduced level of somatic type H1 in the germ-line, as is observed in some other species. The relationship between the P[lacZ] expression pattern in the germarium and the overall expression of the histone cluster suggests there are specific regulatory elements for germ-line expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050144
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    The wingless gene is required for embryonic brain development in Drosophila (1998)
    Springer
    Development genes and evolution 208 (1998), S. 37-45 
    Details
    ISSN: 1432-041X
    Keywords: Key words wingless ; Wnt ; Drosophila ; Brain development ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We have studied the role of the wingless gene in embryonic brain development of Drosophila. wingless is expressed in a large domain in the anlage of the protocerebrum and also transiently in smaller domains in the anlagen of the deutocerebrum and tritocerebrum. Elimination of the wingless gene in null mutants has dramatic effects on the developing protocerebrum; although initially generated, approximately one half of the protocerebrum is deleted in wingless null mutants by apoptotic cell death at late embryonic stages. Using temperature sensitive mutants, a rescue of the mutant phenotype can be achieved by stage-specific expression of functional wingless protein during embryonic stages 9–10. This time period correlates with that of neuroblast specification but preceeds the generation and subsequent loss of protocerebral neurons. Ectopic wingless over-expression in gain-of-function mutants results in dramatically oversized CNS. We conclude that wingless is required for the development of the anterior protocerebral brain region in Drosophila. We propose that an important role of wingless in this part of the developing brain is the determination of neural cell fate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050151
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Naturally occurring genetic variation affects Drosophila photoreceptor determination (1998)
    Springer
    Development genes and evolution 207 (1998), S. 462-470 
    Details
    ISSN: 1432-041X
    Keywords: Key words Genetic variation ; Sevenless ; EGF receptor ; Drosophila ; Photoreceptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The signal transduction pathway controlling determination of the identity of the R7 photoreceptor in the Drosophila eye is shown to harbor high levels of naturally occurring genetic variation. The number of ectopic R7 cells induced by the dosage-sensitive Sev S11.1 transgene that encodes a mildly activated form of the Sevenless tyrosine kinase receptor is highly sensitive to the wild-type genetic background. Phenotypes range from complete suppression to massive overproduction of photoreceptors that exceeds reported effects of known single gene modifiers, and are to some extent sex-dependent. Signaling from the dominant gain-of-function Drosophila Epidermal Growth Factor Receptor (DER-Ellipse) mutations is also sensitive to the genetic backgrounds, but there is no correlation with the effects on Sev S11.1 . This implies that different genes and/or alleles modify the two activated receptor genotypes. The evolutionary significance of the existence of high levels of genetic variation in the absence of normal phenotypic variation is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050137
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Induction by alkaloids and phenobarbital of Family 4 Cytochrome P450s in Drosophila : evidence for involvement in host plant utilization (1998)
    Springer
    Molecular genetics and genomics 259 (1998), S. 54-59 
    Details
    ISSN: 1617-4623
    Keywords: Key words Cytochrome P450 ; Toxin resistance ; Multigene family ; Induction ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In vertebrates, cytochrome P450s of the CYP2 and CYP3 families play a dominant role in drug metabolism, while in insects members of the CYP6 and CYP28 families have been implicated in metabolism of insecticides and toxic natural plant compounds. A degenerate 3′ RACE strategy resulted in the identification of fifteen novel P450s from an alkaloid-resistant species of Drosophila. The strong (17.4-fold) and highly specific induction of a single gene (CYP4D10) by the toxic isoquinoline alkaloids of a commonly utilized host-plant (saguaro cactus) provides the first indication that members of the CYP4 family in insects may play an important role in the maintenance of specific insect-host plant relationships. Strong barbiturate inducibility of CYP4D10 and two other D. mettleri P450 sequences of the CYP4 family was also observed, suggesting a pattern of xenobiotic responsiveness more similar to those of several vertebrate drug-metabolizing enzymes than to putative vertebrate CYP4 homologs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380050788
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Subcellular localization of β-1,3-glucanase in Puccinia recondita f.sp. tritici-infected wheat leaves (1998)
    Springer
    Planta 204 (1998), S. 324-334 
    Details
    ISSN: 1432-2048
    Keywords: Key words:β-1 ; 3-Glucanase ; Immunocytochemistry ; Leaf rust pathogen ; Resistance ; Triticum (pathogen resistance)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. An antiserum raised against the purified 33-kDa β-1,3-glucanase of wheat (Triticum aestivum L.) was employed to investigate the ultrastructural localization of the enzyme in wheat leaves infected with Puccinia recondita Rob. ex Desm. f.sp. tritici Eriks. and Henn. using a post-embedding immunogold labelling technique. In both compatible and incompatible interactions, β-1,3-glucanase was detected in the host plasmalemma and in the domain of the host cell wall near the plasmalemma of the mesophyll cells, but higher concentrations of the enzyme were detected in infected resistant wheat leaves than in infected susceptible ones. β-1,3-Glucanase was also found in the secondary thickening of xylem vessels and in the walls of guard cells, epidermal cells and phloem elements, while no labelling was observed in host organelles, viz. vacuoles, mitochondria, endoplasmic reticulum, Golgi bodies, nuclei and chloroplasts. A low concentration of the enzyme was detected on the intercellular hyphal wall and in the hyphal cytoplasm. In the compatible interaction, β-1,3-glucanase was demonstrated to accumulate predominantly in the haustorial wall and extrahaustorial matrix. In the incompatible interaction, strong labelling for β-1,3-glucanase was found in host cell wall appositions, in the extracellular matrix in the intercellular space, and in electron-dense structures of host origin which occurred in the incompatible interaction only.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004250050263
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Environmental effects on cytoplasmic incompatibility and bacterial load in Wolbachia-infected Drosophila simulans (1998)
    Springer
    Entomologia experimentalis et applicata 86 (1998), S. 13-24 
    Details
    ISSN: 1570-7458
    Keywords: Drosophila ; cytoplasmic incompatibility ; Wolbachia ; temperature ; antibiotics ; density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of high temperatures, antibiotics, nutrition and larval density on cytoplasmic incompatibility caused by a Wolbachia infection were investigated in Drosophila simulans. Exposure of larvae from an infected stock to moderate doses of tetracycline led to complete incompatibility when treated females were crossed to infected males; the same doses only caused a partial restoration of compatibility when treated males were crossed to uninfected females. In crosses with treated females, there was a strong correlation between dose effects on hatch rates and infection levels in embryos produced by these females. Ageing and rearing males at a high temperature led to increased compatibility. However, exposing infected females to a high temperature did not influence their compatibility with infected males. Male temperature effects depended on conditions experienced at the larval stage but not the pupal stage. Exposure to 25 °C reduced the density of Wolbachia in embryos compared with a 19 °C treatment. Low levels of nutrition led to increased compatibility, but no effect of larval crowding was detected. These findings show the ways environmental factors can influence the expression of cytoplasmic incompatibility and suggest that environmental effects may be mediated by bacterial density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003043814761
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Interactions of the Males and Females of Three Sympatric Drosophila virilis-Group Species, D. montana, D. littoralis, and D. lummei, (Diptera: Drosophilidae) in Intra- and Interspecific Courtships in the Wild and in the Laboratory (1998)
    Springer
    Journal of insect behavior 11 (1998), S. 399-417 
    Details
    ISSN: 1572-8889
    Keywords: courtship behavior ; songs ; sexual isolation ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four species of the Drosophila virilis group, D. montana, D. littoralis, D. lummei, and D. ezoana, occur sympatrically in several locations in northern Europe. Courtship interactions between the flies of the three first-mentioned species were observed at malt baits in Kemi, northern Finland, to find out how the flies of different species recognize conspecific individuals and how interspecific courtships differ from intraspecific ones in the wild. Intraspecific courtships (including females of different reproductive stages) and interspecific courtships were also videotaped and analyzed in laboratory. In the wild the males courted both conspecific and allospecific females, even though the species varied in how much the males were attracted to females of different species. Interspecific courtships usually broke off when the male touched the female or when the male and/or the female vibrated his/her wings, producing acoustic cues. In the laboratory males courted conspecific females irrespective of the reproductive stage of the female, even though the courtships directed toward immature and fertilized females usually included only orienting and touching (no licking and singing). D. littoralis, and very rarely D. montana and D. lummei, males courted also allospecific females. In the few interspecific courtships between these three species, where the male proceeded to singing, females responded to male singing by vibrating their wings. This ended the courtship. It is suggested that both the chemical cues affecting female attractivity and the acoustic signals of males and females, which are produced by wing vibration, function in maintaining sexual isolation between these three species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020906815133
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Host Preference Among Populations of Drosophila mojavensis (Diptera: Drosophilidae) that Use Different Host Cacti (1998)
    Springer
    Journal of insect behavior 11 (1998), S. 691-712 
    Details
    ISSN: 1572-8889
    Keywords: cactus ; Drosophila ; geographic variation ; host preference behavior ; Sonoran Desert ; volatiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Previous studies have suggested that all populations of cactophilic Drosophila mojavensis prefer pitaya agria cactus, Stenocereus gummosus, over all other potential hosts for feeding and breeding, including populations that inhabit areas where no agria grows. We sampled five geographically isolated populations of D. mojavensis from nature to assess host choice within and between populations. Host choice tests were performed in a laboratory “olfactometer” by allowing adult D. mojavensis to choose between plumes of synthetic volatile cocktails of two widespread host cacti. Overall, each population showed significant preference for agria volatiles with one exception: a mainland Sonora population that uses organ pipe cactus in nature exhibited preference for organ pipe volatiles, suggesting a possible shift in host preference. The degree of preference for agria volatiles was greatest in a population from southern California that use California barrel cactus as a host. Since southern Californian populations of D. mojavensis are thought to be derived from those in Baja California, preference for agria volatiles is considered a retained ancestral trait. Three populations from Baja California and mainland Mexico that use agria in the wild expressed lower, but similar preferences for agria volatiles. Because populations of D. mojavensis are ancestral to those in mainland Mexico, Arizona, and California, the shift from agria to alternate hosts has not been accompanied by strong changes in host preference behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022398809881
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Some evolutionary consequences of deleterious mutations (1998)
    Springer
    Genetica 102-103 (1998), S. 3-19 
    Details
    ISSN: 1573-6857
    Keywords: mutation rate ; selection ; self-fertilization ; Y chromosomes ; genetic recombination ; Drosophila ; flowering plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Most mutations with observable phenotypic effects are deleterious. Studies of Drosophila and inbred plant populations suggest that a new individual may have a mean number of new deleterious mutations that exceeds one-half. Most of these have relatively small homozygous effects and reduce fitness by 1–2% when heterozygous. Several striking features of present-day organisms have apparently evolved in response to the constant input of deleterious alleles by recurrent mutation. For example, the adaptations of hermaphroditic organisms for outcrossing have been widely interpreted in terms of the benefits of avoiding the reduced fitness of inbred progeny, which is partly due to deleterious mutations. Population genetic models of modifiers of the breeding system in the presence of genome-wide deleterious mutation are reviewed and their predictions related to genetic and comparative data. The evolution of degenerate Y chromosomes is a phenomenon that may be caused by the accumulation of deleterious mutations. The population genetic mechanisms that can drive this degeneration are reviewed and their significance assessed in the light of available data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017066304739
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Mutation and evolution of microsatellites in Drosophila melanogaster (1998)
    Springer
    Genetica 102-103 (1998), S. 359-367 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; microsatellites ; mutation rate ; recombination ; gvariation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Levels of nucleotide polymorphism in the Drosophila melanogaster genome are correlated with rates of recombination. This relationship may be due to hitchhiking of advantageous mutations (selective sweeps) or to continual removal of deleterious mutations from the genome (background selection). One test of the relative contributions of selective sweeps and background selection to the observed levels of variation in the genome of D. melanogaster is to compare levels of nucleotide variability (with a mutation rate on the order of 10-9 per nucleotide per generation) with more rapidly evolving DNA loci such as microsatellites. This test depends critically on details of the mutational process of microsatellites. In this paper, we summarize our studies of microsatellite characteristics and mutation rates in D. melanogaster. We find that D. melanogaster microsatellites are short and have a mutation rate (6.5 × 10-6 per locus per generation) several orders of magnitude lower than mammals studied to date. We further show that genetic variation at 18 dinucleotide repeat microsatellites in a population of D. melanogaster from Maryland is correlated with regional rates of recombination. These and other microsatellite data suggest that both background selection and selective sweeps may contribute to the correlation between DNA sequence variation and recombination in Drosophila.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017083025154
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Environment-influenced expression of polygene mutations isolated from a natural population of Drosophila melanogaster (1998)
    Springer
    Genetica 102-103 (1998), S. 217-228 
    Details
    ISSN: 1573-6857
    Keywords: genotype × environment interaction ; QTLs ; polygenes ; Drosophila ; bristles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Quantitative trait loci (QTLs) affecting sternopleural bristle number in Drosophila melanogaster have been mapped using phenotypic markers and progeny testing. The loci were found on four of the third chromosomes isolated from a natural population. All four loci showed large effects at the standard 25 °C culture temperature, but they responded in different ways when developmental temperature was lowered or raised. These data support the hypothesis that genotype × environment interactions have important influences on polygene expression, and some loci might be silent, or phenotypically neutral, under some conditions but play a large phenotypic role under others. Thus, a full cataloging of the loci contributing to mutational variance for QTLs cannot be done at just a single, controlled environmental condition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017046001047
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Enigma of Y chromosome degeneration: Neo-Y and Neo-X chromosomes of Drosophila miranda a model for sex chromosome evolution (1998)
    Springer
    Genetica 102-103 (1998), S. 409-420 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; evolution ; sex chromosomes ; Y chromosome degeneration ; Y chromosome mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Y chromosome degeneration is characterized by structural changes in the chromosome architecture and expansion of genetic inertness along the Y chromosome. It is generally assumed that the heteromorphic sex chromosome pair has developed from a pair of homologues. Several models have been suggested. We use the unique situation of the secondary sex chromosome pair, neo-Y and neo-X (X2), in Drosophila miranda to analyze molecular mechanisms involved in the evolutionary processes of Y chromosome degeneration. Due to the fusion of one of the autosomes to the Y chromosome (about 2 Mya), a neo-Y chromosome and a neo-X chromosome, designated X2, were formed. Thus, formerly autosomal genes are inherited now on a pair of sex chromosomes in D. miranda. Analyzing DNA sequences from the X2 and neo-Y region, we observed a massive accumulation of DNA insertions on the neo-Y chromosome. From the analysis of several insertion elements, we present compelling evidence that the first step in Y chromosome degeneration is driven by the accumulation of transposable elements, especially retrotransposons. An enrichment of these elements along an evolving Y chromosome could account for the switch from a euchromatic into a heterochromatic chromatin structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017058119760
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Pattern of Chromosomal Localization of the Hoppel Transposable Element Family in the Drosophila melanogaster Subgroup (1998)
    Springer
    Chromosome research 6 (1998), S. 385-396 
    Details
    ISSN: 1573-6849
    Keywords: centromere ; Drosophila ; heterochromatin ; Hoppel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have isolated a Hoppel-like transposon from heterochromatin of the second chromosome of Drosophila melanogaster and used a conserved DNA sequence between the different elements of this family to determine their distribution in both mitotic and polytene chromosomes. The hybridization pattern of polytene chromosomes extends throughout the entire chromocentre, as well as a substantial portion of the fourth chromosome. Analysis of different wild-type strains of D. melanogaster shows variation in euchromatic insertion sites, although most insertions are found near the chromocentre. The positions and the number of heterochromatic clusters of Hoppel on mitotic chromosomes are conserved among the several strains analysed. Accurate mapping of this element was achieved by in situ hybridization on D. melanogaster mitotic chromosomes that had previously been banded with Hoechst 33258. To evaluate the evolutionary stability of this pattern, different species were analysed by in situ hybridization and Southern blotting. We conclude that Hoppel has a conserved distribution in mitotic heterochromatin within the D. melanogaster subgroup, established around 5 million years ago. The overall conservation of heterochormatic organization supports the notion that heterochormatin does perform important structural and functional roles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009277322626
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    The molecular clock revisited: the rate of synonymous vs. replacement change in Drosophila (1998)
    Springer
    Genetica 102-103 (1998), S. 369-382 
    Details
    ISSN: 1573-6857
    Keywords: protein evolution ; Drosophila ; synonymous ; nonsynonymous ; Index of Dispersion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rates of synonymous and nonsynonymous substitution were investigated for 24 genes in three Drosophila species, D. pseudoobscura, D. subobscura, and D. melanogaster. D. pseudoobscura and D. subobscura, two distantly related members of the obscura clade, differ on average by 0.29 synonymous nucleotide substitutions per site. D. melanogaster differs from the two obscura species by an average of 0.81 synonymous substitutions per site. Using a method developed by Gillespie, we investigated the variance to mean ratio, or Index of Dispersion, R, of substitutions along the three species' branches to test the fundamental prediction of the neutral theory of molecular evolution, E(R) = 1. For nonsynonymous substitutions, the average R, Ra is 1.6, which is not significantly different from the neutral theory prediction. Only 5 of the 24 genes had significantly large Ra valves, and 12 of the genes had Ra estimates of less than one. In contrast, the Index of Dispersion for synonymous substitutions was significantly large for 12 of the 24 genes, with an average of Rs = 4.4, also statistically significant. These findings contrast with results for mammals, which showed overdispersion of nonsynonymous substitutions, but not of synonymous substitutions. Weak selection acting to maintain codon bias in Drosophila, but not in mammals, may be important in explaining the high variance in the rate of synonymous substitutions in this group of organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017035109224
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Effects of Courtship Song in Interspecific Crosses Among the Species of the Drosophila auraria Complex (Diptera: Drosophilidae) (1998)
    Springer
    Journal of insect behavior 11 (1998), S. 383-398 
    Details
    ISSN: 1572-8889
    Keywords: Drosophila ; courtship song ; behavior ; female choice ; sexual isolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The courtship behavior and the effects of courtship song in inter- and intraspecific crosses were studied in the four sympatric species of the Drosophila auraria complex: D. auraria, D. biauraria, D. subauraria, and D. triauraria. Orientation, tapping, and vibration (the repertoires of male courtship) were observed in both inter- and intraspecific crosses, suggesting that signals from heterospecific females were enough to elicit such male behaviors. The crossability tests with wingless or winged heterospecific males (tests for wing effects) revealed that winged heterospecific males copulated less than wingless ones in all four species but not all the pairwise cases. Since the crossability tests with aristaless females (deaf) or normal females showed essentially the same results as the tests for wing effects, we concluded that the sound produced by wing vibration plays an important role and that the wing movement itself is less important. These findings suggest that courtship songs are of great importance in mate discrimination and the sexual isolation between the species of this complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020954731063
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Expression of the nuclear gene encoding mitochondrial ATP synthase subunit α in early development of Drosophila and sea urchin (1998)
    Springer
    Molecular biology reports 25 (1998), S. 87-94 
    Details
    ISSN: 1573-4978
    Keywords: mitochondria ; Drosophila ; sea urchin ; ATP synthase ; embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Complementary DNAs encoding nuclear-coded mitochondrial ATP synthase subunit α of Drosophila melanogaster and Strongylocentrotus purpuratus were obtained by a combination of library screening and redundant PCR. The entire coding sequence of the precursor polypeptide was inferred for both species. Southern blots to genomic DNA indicated that the gene is almost certainly single-copy in both organisms. Northern blots to RNA from staged developmental series showed that ATP synthase subunit α mRNA is represented in the egg, declines in abundance during cleavage, and is replenished by zygotic transcription in both species. However, the extent and timing of these changes differ significantly in the two species studied. Nuclear-coded and mitochondrially encoded ATP synthase genes appear to be temporally co-regulated in Drosophila, but not sea urchin development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006868306735
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Calcium-binding proteins and development (1998)
    Springer
    BioMetals 11 (1998), S. 359-372 
    Details
    ISSN: 1572-8773
    Keywords: calcium ; EGF-domains ; cadherins ; integrins ; calmodulin ; cytoskeleton ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The known roles for calcium-binding proteins in developmental signaling pathways are reviewed. Current information on the calcium-binding characteristics of three classes of cell-surface developmental signaling proteins (EGF-domain proteins, cadherins and integrins) is presented together with an overview of the intra-cellular pathways downstream of these surface receptors. The developmental roles delineated to date for the universal intracellular calcium sensor, calmodulin, and its targets, and for calcium-binding regulators of the cytoskeleton are also reviewed.© Kluwer Academic Publishers
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009201824806
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    How Does Offspring Quality Change with Age in Male Drosophila Melanogaster? (1998)
    Springer
    Behavior genetics 28 (1998), S. 395-402 
    Details
    ISSN: 1573-3297
    Keywords: Sexual selection ; age ; fitness ; good genes ; mate choice ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract We examined the relationship of genetic quality to age in male Drosophila melanogaster to test two contrasting hypotheses. The traditional hypothesis is that older males have proven their viability and therefore produce offspring of superior genetic quality. This hypothesis is often evoked as an explanation for female preference for older mates. In contrast, we have recently argued that older fathers may produce offspring of inferior genetic quality. Here, we present results from an experiment designed to measure the genetic quality of offspring produced by 2 day old, 2 week old and 5 week old male D. melanogaster. We found a statistically significant small reduction in larval viability and a similar but statistically non-significant reduction in son mating ability among the offspring of the 5 week old males. Daughter fecundity showed no apparent trend for a reduction nor an increase in performance with increasing age of the fathers. There was no evidence of a difference between the 2 day old and the 2 week old males for any of these three fitness components. These results are in somewhat better accordance with our alternative hypothesis, but the relatively weak and late occurring effects indicate that mate choice based on age may not be a viable strategy in this population.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021677804038
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Developmental Isolation and Subsequent Adult Behavior of Drosophila paulistorum.IV. Courtship (1998)
    Springer
    Behavior genetics 28 (1998), S. 57-65 
    Details
    ISSN: 1573-3297
    Keywords: Courtship ; sexual selection ; sexual isolation ; semispecies ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Early social experiences play important roles in adult Drosophila paulistorummate selection. Differences in courtship between control males and wholly socially isolated males were observed in chambers. Socially isolated males displayed more courtship toward virgin females than did controls. Socially isolated males were more successful in competing for mates. Yet socially isolated males from all six semispecies also displayed notable frequencies of homosexual behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021460832378
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Ultrastructural, morphometrical and immunocytochemical analyses of the exocrine pancreas in a hibernating dormouse (1998)
    Springer
    Cell & tissue research 292 (1998), S. 531-541 
    Details
    ISSN: 1432-0878
    Keywords: Key words Pancreas ; exocrine ; Hibernation ; Amylase ; Immunocytochemistry ; Muscardinus avellanarius (Rodentia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Pancreatic acinar cells of euthermic, hibernating and arousing individuals of the hazel dormouse Muscardinus avellanarius (Gliridae) have been observed at the electron-microscopic level and analysed by means of ultrastructural morphometry and immunocytochemistry in order to investigate possible fine structural changes of cellular components during periods of strikingly different degrees of metabolic activity. During hibernation, the cisternae of the rough endoplasmic reticulum (RER) flatten assuming a parallel pattern, the Golgi apparatus is extremely reduced and the mitochondria contain many electron-dense particles. The cell nuclei appear irregularly shaped, with deep indentations containing small zymogen granules. They also contain abundant coiled bodies and unusual constituents, such as amorphous bodies and dense granular bodies. Large numbers of zymogen granules occur in all animals. However, the acinar lumina are open and filled with zymogen only in euthermic animals, whereas, in hibernating and arousing individuals, they appear to be closed. Morphometrical analyses indicate that, in pancreatic acinar cells, nuclei and zymogen granules significantly decrease in size from euthermia to hibernation, probably reflecting a drastic decrease of metabolic activities, mainly protein synthesis and processing. In all the studied animals, immunocytochemistry with specific antibodies has revealed an increasing gradient in α-amylase content along the RER-Golgi-zymogen granule pathway, reflecting the protein concentration along the secretory pathway. Moreover, during deep hibernation, significantly larger amounts of α-amylase accumulate in RER and zymogen granules in comparison to the other seasonal phases analysed. Upon arousal, all cytoplasmic and nuclear constituents restore their euthermic aspect and all morphometrical and immunocytochemical parameters exhibit the euthermic values, thereby indicating a rapid resumption of metabolic activities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051082
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Expression pattern for adrenomedullin during pancreatic development in the rat reveals a common precursor with other endocrine cell types (1998)
    Springer
    Cell & tissue research 293 (1998), S. 95-100 
    Details
    ISSN: 1432-0878
    Keywords: Key words Adrenomedullin ; Pancreas ; Development ; Immunocytochemistry ; Colocalizations ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Adrenomedullin is an α-amidated 52-amino acid peptide involved in many physiological actions, among others the regulation of insulin secretion. Using immunohistochemical methods, we found that adrenomedullin immunoreactivity first appears at day 11.5 of embryonic development in the rat, coinciding with the appearance of pancreatic glucagon. The early appearance of adrenomedullin in the developing pancreas may indicate an active involvement in either the morphogenesis of the organ or its endocrine/paracrine/autocrine hormone regulation during intrauterine life. We also investigated the pattern of colocalizations of adrenomedullin with the other pancreatic hormones. At some point during development all the cell types express adrenomedullin, progressively evolving towards the adult pattern where only the pancreatic polypeptide cells contain a strong immunoreactivity for adrenomedullin. At this point the remaining cells of the islet are, in general, weakly stained. This sequential and time-dependent expression of adrenomedullin suggests a tight regulation similar to that observed for other modulatory substances responsible for embryonic morphogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051101
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Immunocytochemistry and in situ hybridization studies of pepsinogen C-producing cells in developing rat fundic glands (1998)
    Springer
    Cell & tissue research 293 (1998), S. 121-131 
    Details
    ISSN: 1432-0878
    Keywords: Key words Pepsinogen C ; Ontogeny ; Mucous neck cell ; Chief cell ; Intermediate mucopeptic cell ; Immunocytochemistry ; In situ hybridization ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The ontogeny of pepsinogen C-producing cells in rat fundic glands was studied by means of light and electron microscopy using an antiserum raised against a synthetic peptide based on rat pepsinogen C. To confirm the immunocytochemistry results, the expression of rat pepsinogen C messenger RNA (mRNA) in the fundic gland was also examined by in situ hybridization using a digoxigenin-labeled RNA probe. In adult rats, pepsinogen C was produced by chief cells, mucous neck cells, and intermediate mucopeptic cells. Pepsinogen C-producing cells appeared in embryos as early as 18.5 days’ gestation. The development of these cells could be classified into four stages: (1) 18.5 days’ gestation to 0.5 days after birth; (2) 0.5 days to 2 weeks after birth; (3) 3–4 weeks after birth; (4) 4–8 weeks after birth. In embryos and young animals, pepsinogen C-producing cells were mucopeptic cells. By 4 weeks after birth, mucous neck cells could be distinguished morphologically. The maturation stages of the chief cells could be traced by electron microscopy along the longitudinal axis of the rat fundic gland by double-staining with anti-pepsinogen C antibody and periodic acid-thiocarbohydrazide-silver proteinate. Positive reactions for pepsinogen C and pepsinogen C mRNA expression were detected in mucous neck cells. Therefore, we conclude that mucous neck cells are precursor cells of chief cells. Mucous neck cells, intermediate cells, and chief cells are in the same differentiating cell lineage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051104
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Quantitative analysis of inputs to somatostatin-immunoreactive descending interneurons in the myenteric plexus of the guinea-pig small intestine (1998)
    Springer
    Cell & tissue research 294 (1998), S. 219-226 
    Details
    ISSN: 1432-0878
    Keywords: Key words Enteric nervous system ; Somatostatin ; Immunocytochemistry ; Intestinal motility ; Synaptic connections ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Somatostatin immunoreactivity occurs in a specific subgroup of cholinergic descending interneurons in the myenteric plexus of the guinea-pig small intestine. In the present work, we made light- and electron-microscopic investigations of chemically defined inputs to these neurons, in order that the origins of the connections of other neurons with them could be deduced. Somatostatin-immunoreactive synapses and close contacts were found on the cell bodies and filamentous processes of somatostatin neurons; these were 84% of all inputs. It is thus confirmed that this class of interneuron forms chains that project anally. Descending interneurons with immunoreactivity for nitric oxide synthase provided 14% of inputs to somatostatin-immunoreactive descending interneurons. An antiserum against a calcium-binding protein, calbindin, was used as marker for the majority of intrinsic primary afferent neurons, AH/Dogiel type II neurons; this class of neurons provided only 2.5% of the inputs to somatostatin-immunoreactive descending interneurons. We conclude that somatostatin-immunoreactive descending interneurons are involved in the conduction of impulses distally along the full length of the small intestine, but receive only a minor input from calbindin-immunoreactive primary afferent neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051171
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Immunocytochemical localization of annexin 5, a calcium-dependent phospholipid-binding protein, in rat endocrine organs (1998)
    Springer
    Cell & tissue research 292 (1998), S. 85-89 
    Details
    ISSN: 1432-0878
    Keywords: Key words Annexin 5 ; Immunocytochemistry ; Pituitary ; Ovary ; Testis ; Adrenal gland ; Thyroid gland ; Rat (wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Annexin 5, a unique calcium- and phospholipid-binding protein, has been investigated for its specific distribution in rat endocrine organs by immunocytochemistry with a specific antiserum to recombinant rat annexin 5. Follicular epithelial cells and parafollicular cells of the thyroid gland, adrenocortical cells of the zona fasciculata and zona reticularis, luteal cells, testicular interstitial cells, and Sertoli cells were shown to contain annexin 5. To examine whether the synthesis of annexin 5 would be affected by a change in humoral signal, the distribution of annexin 5 in the anterior pituitary was examined three weeks after ovariectomy. The withdrawal of ovarian hormones induced huge castration cells in the anterior pituitary gland, which contained abundant annexin 5. Annexin 5 was not detected in the pineal gland, the parathyroid gland, the islet of Langerhans, the adrenal medulla, zona glomerulosa cells, and granulosa cells. Since annexin 5 was shown to exist in many of the endocrine tissues examined, to be localized in specific cell types, and to be abundant in castration cells, it is suggested that annexin 5 contributes to secretory cell functions, which may be common to endocrine cells secreting chemically different hormones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051037
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Chymotrypsin gene expression in rat peripheral organs (1998)
    Springer
    Cell & tissue research 292 (1998), S. 345-354 
    Details
    ISSN: 1432-0878
    Keywords: Key words Pancreas ; Stomach ; Duodenum ; Ribonuclease protection assay ; Immunocytochemistry ; Protease ; Rat ; (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Prior studies have revealed the presence of chymotrypsinlike protease in peripheral organs, although no definitive evidence for the synthesis of this enzyme in tissue other than the pancreas is available. In an attempt to detect chymotrypsinogen mRNA in peripheral organs, a fragment of the pancreatic chymotrypsin mRNA from rat was amplified using PCR. The sequence was identified as a portion of the rat chymotrypsin B gene overlapping exon 5 through exon 7. It was subcloned into the pGEM-4Z vector and used as a template for the vitro transcription of an antisense riboprobe. Using ribonuclease protection and Northern blot analyses, chymotrypsin mRNA was detected in the rat pancreas, stomach, duodenum, ovary, and spleen. Monoclonal and polyclonal antisera against chymotrypsin detected chymotrypsinlike immunoreactivity in rat and human pancreas, rat stomach, duodenum and jejunum. Electrophoresis and immunoblotting revealed chymotrypsin-chymotrypsinogen bands (25–29 kDa) in the stomach and duodenum. Synthesis of a potent protease such as chymotrypsin in tissue other than pancreas is significant, suggesting a potential physiological and/or pathological role in these tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051065
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Immunocytochemical alterations in the intra-acrosomal antigen MN7 during epididymal maturation of guinea pig spermatozoa (1998)
    Springer
    Cell & tissue research 292 (1998), S. 427-433 
    Details
    ISSN: 1432-0878
    Keywords: Key words Acrosome ; Epididymal maturation ; Monoclonal antibody ; Immunocytochemistry ; Spermatozoa ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  We have previously shown that a 90-kDa intra-acrosomal antigen, MN7, is restricted to the anterior acrosomal region of mouse, rat, and hamster spermatozoa. The present study has examined the localization and the behavior of MN7 during sperm maturation in the epididymis of the guinea pig by immunoelectron microscopy. MN7 showed not only a specific localization in the apical segment of the guinea pig sperm acrosome, but also a distinct alteration during maturation, as follows. MN7 was exclusively found both at the dorsal matrix and on the outer acrosome membrane (OAM)/matrix-associated materials in the apical segment. MN7 was initially distributed throughout the electron-lucent dorsal matrix in immature sperm but, during maturation, became more restricted to the spherical bodies within the electron-lucent area. MN7 on OAM/matrix-associated materials was first distributed along the ventral margin and the small area posterior to the dorsal matrix but, during maturation, disappeared from the ventral margin and became restricted to the dorsal region. These results indicate that MN7 is a good tool for studying the stepwise maturation of epididymal spermatozoa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051071
    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...