ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Artikel  (360)
  • Weitere Quellen
  • evolution  (289)
  • diffusion
  • Springer  (360)
  • American Geophysical Union
  • American Institute of Physics (AIP)
  • American Physical Society
  • Blackwell Publishing Ltd
  • Institute of Physics
  • 2000-2004  (70)
  • 1995-1999  (290)
  • 1945-1949
  • 1935-1939
  • Biologie  (305)
  • Physik  (60)
  • Allgemeine Naturwissenschaft
Sammlung
  • Artikel  (360)
  • Weitere Quellen
Datenquelle
Schlagwörter
Verlag/Herausgeber
  • Springer  (360)
  • American Geophysical Union
  • American Institute of Physics (AIP)
  • American Physical Society
  • Blackwell Publishing Ltd
    • +
Erscheinungszeitraum
Jahr
Thema
  • 1
    Digitale Medien
    Digitale Medien
    Die Lage der Vogelsystematik (2000)
    Springer
    Journal of ornithology 141 (2000), S. 263-274 
    Details
    ISSN: 1439-0361
    Schlagwort(e): Systematics ; evolution ; anagenesis ; genealogy ; reference system
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Verglichen mit anderen Tiergruppen, scheint die artliche Bestandsaufnahme der rezenten Vögel nahezu abgeschlossen zu sein. Doch ist das System der Vögel weiterhin umstritten und mit vielen Neuerungen konfrontiert. Die Gründe dafür liegen hauptsächlich in neuen, vor allem molekularbiologischen Methoden und in den unerwartet reichen Fossilfunden der jüngsten Zeit. Als Beispiele werden Altgaumenvögel, Kranichvögel, Ibisse, Flamingos, Mausvögel, Hopfe und Sperlingsvögel kurz behandelt. Die hier erzielten Fortschritte lassen die Befürchtung Stresemanns, die Großsystematik der Vögel sei mit den vorhandenen Methoden phylogenetisch nicht interpretierbar, zunächst als unbergründet erscheinen. Doch erwachsen einer solchen Interpretation andere Hindernisse, deren Bedeutung bisher zu wenig beachtet wurde, nämlich Parallelentwicklungen, die viel verbreiteter sind als gemeinhin angenommen. Ihre Häufigkeit lässt sich sogar mit evolutionsbiologischen Argumenten begründen. Es ist deshalb nicht zu erwarten, dass die Diskussionen um das „richtige“ System bald verstummen. Um dennoch die Eindeutigkeit der Information in nicht-systematischen Veröffentlichungen zu wahren, wird empfohlen ein etabliertes Referenzsystem auf Zeit zu wählen.
    Notizen: Summary Unlike in most animal classes the inventory of extant species of the class Aves seems to be almost complete. Nevertheless avian systematics is challenged by many novelties and seems far from being settled. This is caused mainly by the application of novel methods of molecular analysis to phylogenetic problems and by the unexpectedly rich fossil record collected within the last 10–20 years. Examples from the Palaeognathae, Gruiformes, Threskiornithidae, Phoenicopteridae, Coliiformes, Upupiformes and Passeriformes are briefly treated. The progress in the field seems to disprove Stresemann's pessimistic view that the phylogeny of higher categories (orders) cannot be reconstructed by the available methods. However, phylogenetic interpretations are impeded by obstacles not considered by Stresemann and highly underestimated in most cases, namely by multiple independent developments leading to identical features. Frequent parallel developments are to be expected for theoretical evolutionary reasons. The diagnosis of such homoplasies can be extremely difficult or even impossible. Therefore we cannot expect the discussion about the “best” system of birds to end in the near future. Considering this dynamic situation in systematics, it is recommended to maintain unambiguousness of information in not strictly systematic publications by refering to a well established system as a temporally limited reference.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02462236
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Impaired host odor perception in hybrids between the sibling species Rhagoletis pomonella and R. mendax (1996)
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 163-165 
    Details
    ISSN: 1570-7458
    Schlagwort(e): olfaction ; EAG ; sensory physiology ; antennal sensitivity ; interspecies hybrids ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00194749
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Specificity of a Y-linked gene in the flea beetle Phyllotreta nemorum for defences in Barbarea vulgaris (1999)
    Springer
    Entomologia experimentalis et applicata 91 (1999), S. 359-368 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Barbarea vulgaris ssp. arcuata ; Cruciferae ; Phyllotreta nemorum ; Chrysomelidae ; Alticinae ; flea beetle ; plant defence ; host plant range ; near-isogenic ; Y-linkage ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A Y-linked gene (R-gene) in the flea beetle Phyllotreta nemorum L. (Coleoptera: Chrysomelidae: Alticinae) confer the ability of larvae to survive on types of the plant Barbarea vulgaris R.Br. (Brassicaceae) which are immune to attack by susceptible conspecifics. Two near-isogenic flea beetle lines were developed. The YE-line contained the Y-linked R-gene, and male larvae from this line survived on B. vulgaris. The ST-line did not contain the gene and did not survive on the plant. The YE-line had been developed through 8–9 generations of backcrosses (YE-males with ST-females) and the two lines were considered to be isogenic except for genes located on the Y-chromosome. A single copy of the Y-linked gene is sufficient to transfer a susceptible genotype (ST) into a resistant genotype (YE) which is able to utilize a plant that is immune to attack by specimens without R-genes. The Y-linked gene had no effects on survival on other plant species tested. The gene did not have any effect on developmental times and weights of adult beetles reared on other plants than B. vulgaris. Developmental times of larvae with the Y-linked gene were longer on B. vulgaris than on normal host plants, R. sativus and S. arvensis, but the adults obtained the same size on these plant species. No trade-offs of the Y-linked gene were discovered. The results suggest that the occurrence of the Y-linked gene is a derived trait which has enabled the flea beetle to expand its host plant range. The evolution of a host shift to B. vulgaris seems not to be favoured by the presence of this single gene.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003622512914
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    Emergence and Maintenance of Sex among Diploid Organisms Aided by Assortative Mating (2000)
    Springer
    Acta biotheoretica 48 (2000), S. 137-147 
    Details
    ISSN: 1572-8358
    Schlagwort(e): Sex ; sexual selection ; mate selection ; evolution ; ploidy ; assortative mating ; recombination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Using computer simulations I studied the simultaneous effect of variable environments, mutation rates, ploidy, number of loci subject to evolution and random and assortative mating on various reproductive systems. The simulations showed that mutants for sex and recombination are evolutionarily stable, displacing alleles for monosexuality in diploid populations mating assortatively under variable selection pressure. Assortative mating reduced excessive allelic variance induced by recombination and sex, especially among diploids. Results suggest a novel adaptive value for sex and recombination. They show that the adaptive value of diploidy and that of the segregation of sexes is different to that of sex and recombination. The results suggest that the emergence of sex had to be preceded by the emergence of diploid monosexual organisms and provide an explanation for the emergence and maintenance of sex among diploids and for the scarcity of sex among haploid organisms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1002765101959
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    Digitale Medien
    Digitale Medien
    Respective Role of the Axialand Appendicular Systems in Relation to the Transition to Limblessness (1998)
    Springer
    Acta biotheoretica 46 (1998), S. 141-156 
    Details
    ISSN: 1572-8358
    Schlagwort(e): locomotion ; Squamata ; lizards ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In lower quadrupedal vertebrates locomotor efficiency seems to result from the associate movements of the axial and appendicular systems, which are totally independent in structure and embryological origin. The curvature of the trunk, produced by a standing wave, magnifies the propulsive action of the limbs. In intermediate forms, the association of an elongate trunk with limbs reduced in size brings about functional consequences which may be noticeably diverse according to the degree of trunk elongation and limb reduction. According to environmental constraints, animals search for better locomotor efficiency, which implies the maintenance or breakage of this association of both locomotor systems. In some cases, limb action on the ground is added to the axial wave action through a perfect mutual adjustment of rhythmic activity, until mechanical inefficiency of the limbs is reached by possible loss of contact with the ground. In other cases, the limbs dragged on the ground during the stance phase act against the axial action or, on the contrary, are inhibited by the axial system. A review of available data tries to contribute to an understanding of the respective roles of both systems in the transition to limblessness.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1001129920394
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 6
    Digitale Medien
    Digitale Medien
    Chemosensory basis of feeding and oviposition behaviour in herbivorous insects: a glance at the periphery (1996)
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 7-13 
    Details
    ISSN: 1570-7458
    Schlagwort(e): host-plant selection ; sensory physiology ; neural coding ; deterrents ; peripheral interactions ; receptor sites ; genetics of insects ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Recent advances in our understanding of the relationship between chemosensory and behavioural responses to phytochemicals come from a number of studies on ovipositional and food selection behaviour of flies, butterflies, moths and beetles. Establishing input-output relationships has provided insight into the way in which the activity of chemoreceptors is translated into host-plant selection behaviour. This was achieved for both the qualitative contrast acceptance/rejection and for quantifiable preference hierarchies. By now it is clear that the subtlety of coding the complex phytochemical profiles offered by potential host plants relies on across-fibre patterns or ensemblefiring of taste neurons. Progress along these lines depends on unravelling processing pathways in the central nervous system, still a largely unexplored area in herbivorous insects. Increased interest can be noted for the mechanisms operating during the most peripheral events of chemoreception: the interaction of phytochemical and chemoreceptor, determining the specificity of recognition. Evidence for ‘peripheral integration’ has accumulated. Deterrent receptors have an especially puzzling nature. Although such cells respond to a wide array of structurally diverse secondary plant metabolites, their sensitivity profile differs between closely related species. To what extent membrane-bound receptor molecules are involved and what degree of specificity is conferred by these, is largely unknown. Sensitivity to a certain group or class of compounds is determined by single genes in several cases. This allows for a scenario in which single gene mutations affect stimulus-receptor interactions, which might concurrently affect host-plant selection behaviour.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00194713
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 7
    Digitale Medien
    Digitale Medien
    Insect-plant relations: overview from the symposium (1996)
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 320-324 
    Details
    ISSN: 1570-7458
    Schlagwort(e): multitrophic interactions ; phylogeny ; evolution ; fitness
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00194783
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 8
    Digitale Medien
    Digitale Medien
    Multitrophic effects of herbivore-induced plant volatiles in an evolutionary context (2000)
    Springer
    Entomologia experimentalis et applicata 97 (2000), S. 237-249 
    Details
    ISSN: 1570-7458
    Schlagwort(e): herbivores ; predators ; parasitoids ; mutualism ; induced defence ; behaviour ; ecology ; evolution ; sensory physiology ; plant fitness ; pathogens
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Herbivorous and carnivorous arthropods use plant volatiles when foraging for food. In response to herbivory, plants emit a blend that may be quantitatively and qualitatively different from the blend emitted when intact. This induced volatile blend alters the interactions of the plant with its environment. We review recent developments regarding the induction mechanism as well as the ecological consequences in a multitrophic and evolutionary context. It has been well established that carnivores (predators and parasitoids) are attracted by the volatiles induced by their herbivorous victims. This concerns an active plant response. In the case of attraction of predators, this is likely to result in a fitness benefit to the plant, because through consumption a predator removes the herbivores from the plant. However, the benefit to the plant is less clear when parasitoids are attracted, because parasitisation does usually not result in an instantaneous or in a complete termination of consumption by the herbivore. Recently, empirical evidence has been obtained that shows that the plant's response can increase plant fitness, in terms of seed production, due to a reduced consumption rate of parasitized herbivores. However, apart from a benefit from attracting carnivores, the induced volatiles can have a serious cost because there is an increasing number of studies that show that herbivores can be attracted. However, this does not necessarily result in settlement of the herbivores on the emitting plant. The presence of cues from herbivores and/or carnivores that indicate that the plant is a competitor- and/or enemy-dense space, may lead to an avoidance response. Thus, the benefit of emission of induced volatiles is likely to depend on the prevailing faunal composition. Whether plants can adjust their response and influence the emission of the induced volatiles, taking the prevalent environmental conditions into account, is an interesting question that needs to be addressed. The induced volatiles may also affect interactions of the emitting plant with its neighbours, e.g., through altered competitive ability or by the neighbour exploiting the emitted information. Major questions to be addressed in this research field comprise mechanistic aspects, such as the identification of the minimally effective blend of volatiles that explains the attraction of carnivores to herbivore-infested plants, and evolutionary aspects such as the fitness consequences of induced volatiles. The elucidation of mechanistic aspects is important for addressing ecological and evolutionary questions. For instance, an important tool to address ecological and evolutionary aspects would be to have plant pairs that differ in only a single trait. Such plants are likely to become available in the near future as a result of mechanistic studies on signal-transduction pathways and an increased interest in molecular genetics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004111624780
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 9
    Digitale Medien
    Digitale Medien
    Specialist deterrent chemoreceptors enable Pieris caterpillars to discriminate between chemically different deterrents (1999)
    Springer
    Entomologia experimentalis et applicata 91 (1999), S. 29-35 
    Details
    ISSN: 1570-7458
    Schlagwort(e): chemoreception ; deterrents ; Pieris ; Brassicaceae ; cardenolides ; host-plant selection ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Pieris butterflies (Lepidoptera: Pieridae) are specialist herbivores of cruciferous plants. They exploit glucosinolates, secondary plant metabolites chemotaxonomically characteristic for this plant family, as token stimuli. In addition to particular glucosinolates, some genera of the Cruciferae contain cardenolides, steroidal allelochemicals that act as potent feeding and oviposition deterrents to several Pieris species. We investigated the sensory mechanisms by which these compounds are perceived in larvae. Pieris caterpillars and many other lepidopterous species are endowed with so-called generalist deterrent receptors, that respond to a broad spectrum of secondary plant substances. In Pieris caterpillars we found a second type of deterrent chemoreceptor in maxillary styloconic taste sensilla. This neuron is very sensitive to cardenolides (threshold 0.1–0.3 μM). The generalist deterrent receptor also responds to these substances but its threshold lies at 50–100× higher concentrations. In behavioural preference experiments Pieris brassicae L. caterpillars preferred cardenolide-treated cabbage leaf discs when confronted with a choice between them and a deterrent substance that does not occur in the Brassicaceae. The cardenolides acted as potent deterrents when offered against untreated cabbage leaf discs. This demonstrates that the balance of activity elicited in the two types of deterrent chemoreceptors determines the behavioural decision.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003645222599
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 10
    Digitale Medien
    Digitale Medien
    On the Adaptive Value of Some Mate Selection Strategies (1999)
    Springer
    Acta biotheoretica 47 (1999), S. 29-40 
    Details
    ISSN: 1572-8358
    Schlagwort(e): Sexual selection ; mate selection ; gamete selection ; evolution ; ploidy ; asssortative mating
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Results of an agent-based computer simulation of the evolution of diploid sexual organisms showed that several mate selection strategies confer much higher average fitness to the simulated populations, and higher evolutionary stability to the alleles coding for these strategies, than random mating. Strategies which select for 'good genes' were very successful, and so were strategies based on assortative mating. The results support the hypothesis that mating is not likely to be random in nature and that the most successful mate selection strategies are those based on assortative mating or on advantageous genes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1002022126388
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 11
    Digitale Medien
    Digitale Medien
    Genetics of the ability of Phyllotreta nemorum larvae to survive in an atypical host plant, Barbarea vulgaris ssp. arcuata (1997)
    Springer
    Entomologia experimentalis et applicata 82 (1997), S. 37-44 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Barbarea vulgaris ; Cruciferae ; Phyllotreta nemorum ; Chrysomelidae ; Alticinae ; flea beetle ; plant defence ; genetics ; sex-linkage ; X- and Y-chromosome ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A polymorphism in host plant exploitation has been discovered in the flea beetle, Phyllotreta nemorum L. (Coleoptera: Chrysomelidae: Alticinae) where one resistant population is able to use Barbarea vulgaris R.Br. ssp. arcuata (Opiz.) Simkovics (Brassicaceae) as a host plant while a susceptible population is not. Crosses (F1, F2, and backcrosses) between the two flea beetle populations were made, and survival of the progeny on B. v. ssp. arcuata was measured. The ability of P. nemorum larvae to survive in this plant species depended on the presence of major, dominant genes (R-genes). The two most abundant R-genes in the resistant flea beetle population were X- and Y-linked, respectively. The use of B. v. ssp. arcuata as a natural host plant by the resistant population of P. nemorum seems to be an extension of the host plant range of the species. The role of sex-linked genes in the evolution of host range is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1002938912809
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 12
    Digitale Medien
    Digitale Medien
    Variation in defences of the plant Barbarea vulgaris and in counteradaptations by the flea beetle Phyllotreta nemorum (1997)
    Springer
    Entomologia experimentalis et applicata 82 (1997), S. 25-35 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Barbarea vulgaris ; Cruciferae ; Phyllotreta nemorum ; Chrysomelidae ; Alticinae ; flea beetle ; plant defence ; resistance ; host plant ; variation ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Several sorts of variation in the interaction between the insect, Phyllotreta nemorum L. (Coleoptera:Chrysomelidae:Alticinae), and the plant, Barbarea vulgaris R.Br. (Brassicaceae), have been discovered: 1) genetic differences in the levels of defences in the plant, 2) genetic differences in the ability of insects to cope with the plant defences, 3) seasonal variation in levels of defences in the plant, and 4) differences between leaf types in levels of defences. Two plant accessions were suitable for larval development throughout the season while the remaining nine accessions were more or less unsuitable for larvae from the ‘susceptible’ T-population at least at certain times of the year. All accessions were suitable for the ‘resistant’ E-population throughout the year. There was a seasonal variation in levels of defences in some accessions which were unsuitable for the T-population during the summer period when beetles were present, but not during autumn and spring when the beetle were hibernating. Upper (younger) cauline leaves of these accessions had higher levels of defences than lower (older) cauline leaves. The resistant E-population used B. vulgaris as a natural host plant while the susceptible T-population did not. The use of B. vulgaris as a natural host plant by the E-population of P. nemorum seems to be an extension of the host plant range of the species. Variation in plant defences may have facilitated the switch in host plant use by the resistant flea beetle population.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1002990929647
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 13
    Digitale Medien
    Digitale Medien
    The making of a pest: recruitment of Meligethes aeneus onto oilseed Brassicas (2000)
    Springer
    Entomologia experimentalis et applicata 95 (2000), S. 141-149 
    Details
    ISSN: 1570-7458
    Schlagwort(e): ecology ; reproductive success ; fecundity ; intraspecific competition ; evolution ; pest outbreaks ; pest control ; chemical control ; economic threshold ; oilseed rape ; turnip rape
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Populations of the rapeseed pollen beetle Meligethes aeneus F. (Col., Nitidulidae) from areas with 0–16 years of history of intensive rapeseed growing were compared for key ecological characters. During the first 16 years of rapeseed cultivation the reproductive success of M. aeneus increased 200–300% over that of the beetles living on the natural host plants, cruciferous weeds. The increase was linear over time and statistically highly significant, and it did not appear to be related to food quality or to the size of the beetles. During the same period the tolerance to intraspecific competition decreased, possibly due to the relative absence of such competition on the new crop. Furthermore, the optimum population density for M. aeneus to maximize the size of its next generation on summer turnip rape was determined to be 0.5–1.0 beetles/plant, which is slightly below the economic threshold for chemical control (1 beetle/plant). Therefore the practical protection of the rapeseed yield also ensures the highest possible pest population size for the next year. These mechanisms may in part explain the particular noxiousness of the species as a pest all over Europe. In general these data show that after the introduction of a new crop plant into a region, significant changes during the recruitment process in a pestiferous insect may take place, contributing to the future pest status of the insect. It is suggested that such genetic and ecological changes in insects may be a more common mechanism than previously thought in initiating and sustaining pest outbreaks, and that conventional pest management methods may enhance that effect.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003947706788
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 14
    Digitale Medien
    Digitale Medien
    Copulatory Courtship in Drosophila: Behavior and Songs of D. birchii and D. serrata (2000)
    Springer
    Journal of insect behavior 13 (2000), S. 71-86 
    Details
    ISSN: 1572-8889
    Schlagwort(e): copulatory courtship ; behavioral interactions ; songs ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract D. birchii and D. serrata, two endemic Australian Drosophila species, have a copulatory courtship. The males of these species begin to court the female after mounting her and often go on with the courtship after the copulation is over. In the present paper we have described behavioral interactions between the male and the female and analyzed acoustic signals produced by the flies during courtship. Species differences were more pronounced in female than in male behavior. Variation within the species was obvious in the relative proportions of time the flies spent in different behaviors. Even though courtship took place nearly solely during copulation, some remains of precopulatory courtship were observed in both species. It is suggested that copulatory courtship exhibited by D. birchii and D. serrata flies is a derived rather than a primitive character.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007715609756
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 15
    Digitale Medien
    Digitale Medien
    Diffusion of short-chain molecules on metal surfaces (1996)
    Springer
    Adsorption 2 (1996), S. 77-87 
    Details
    ISSN: 1572-8757
    Schlagwort(e): diffusion ; molecular-dynamics simulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract In this paper, we review our recent theoretical and simulation studies of the surface diffusion of n-alkanes, ranging in size from ethane to hexadecane, physically adsorbed on Pt(111). The model system exhibits many features seen experimentally. Through both animation of the molecular trajectories and determination of the minimum-energy path for nearest-neighbor hopping, we find that the shorter molecules (ethane through octane) all have similar diffusion mechanisms, involving coupled translation and rigid rod-like rotation in the surface plane. In addition, the diffusion energy barriers for these molecules increase nearly linearly with chain length in both the static and dynamic calculations. The diffusion of decane and hexadecane does not adhere to the trends for the shorter molecules and a decrease can be observed in the dynamical diffusion energies for these molecules. The diffusion of the longer molecules involves hops, with unique mechanisms, to second and third neighbor sites. Our static analysis has indicated, for decane, that the diffusion-energy barrier for third-neighbor hopping is lower than that for nearest-neighbor hopping and is in agreement with the trend seen in the dynamical diffusion barriers. Even though there is agreement between theoretical and simulated diffusion energy barriers for many of the molecules, the motion observed in the MD simulations does not agree with the assumptions of the hopping model. A model that can incorporate the influence of long flights would provide a more realistic description of the motion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00127101
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 16
    Digitale Medien
    Digitale Medien
    Molecular dynamics simulations of osmosis and reverse osmosis in solutions (1996)
    Springer
    Adsorption 2 (1996), S. 95-101 
    Details
    ISSN: 1572-8757
    Schlagwort(e): osmosis ; reverse osmosis ; adsorption ; diffusion ; molecular dynamics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Computer simulation studies using the method of molecular dynamics have been carried out to investigate osmosis and reverse osmosis in solutions separated by semi-permeable membranes. The method has been used to study the dynamic approach to equilibrium in such systems from their initial nonequilibrium state. In addition density profiles of both the solute and solvent molecules have been investigated, especially near the walls for adsorption effects. Finally the diffusion coefficients and osmotic pressure have also been measured. Our results show both osmosis and reverse osmosis, as well as a smooth transition between the two when either the solution concentration is changed, or the density (pressure) difference between the solvent and solution compartments is varied. We believe this new method can be used to improve our understanding of these two important phenomena at the molecular level.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00127103
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 17
    Digitale Medien
    Digitale Medien
    Analysis of ZLC desorption curves for gaseous systems (1996)
    Springer
    Adsorption 2 (1996), S. 133-143 
    Details
    ISSN: 1572-8757
    Schlagwort(e): diffusion ; sorption kinetics ; ZLC
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract The theoretical model and underlying assumptions used in the analysis of ZLC (zero length column) desorption curves are examined in detail. It is shown that the long time analysis generally yields reliable diffusivity values although, if the initial equilibrium condition is not properly established there will be significant error in the apparent equilibrium constant. The short time analysis is much more sensitive to such errors and a modified way of data analysis is suggested to overcome this problem. Varying the initial equilibration time provides an alternative ZLC experiment that can be used to establish the nature of the rate controlling mass transfer resistance. The utility of this approach is illustrated experimentally for the system C3H8-13X zeolite.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00127043
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 18
    Digitale Medien
    Digitale Medien
    Application of the thermal frequency response method and of pulsed field gradient NMR to study water diffusion in zeolite NaX (1996)
    Springer
    Adsorption 2 (1996), S. 205-216 
    Details
    ISSN: 1572-8757
    Schlagwort(e): diffusion ; kinetic measurements ; NaX zeolite ; water
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract The thermal frequency response and pulsed field gradient NMR methods are applied in a comparative study of water diffusion in zeolite NaX under non-equilibrium and equilibrium conditions. The obtained results are found to be in satisfactory agreement with each other, indicating that by applying the thermal frequency response method, complications due to uncontrolled water adsorption at the chamber walls inherent in conventional frequency response measurements may be circumvented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00128302
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 19
    Digitale Medien
    Digitale Medien
    Frequency response analysis of a closed diffusion cell with two resonators (1996)
    Springer
    Adsorption 2 (1996), S. 265-277 
    Details
    ISSN: 1572-8757
    Schlagwort(e): frequency response ; diffusion cell ; kinetics ; diffusion ; heat effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract This paper deals with frequency response (FR) analysis of a closed diffusion cell system with two resonators, that is both the LHS and RHS volumes are modulated. The analysis is made for a homogeneous particle described by a single effective diffusivity as well as a biporous pellet described by macropore and micropore diffusions. It is shown that if the perturbation of the volume of the reservoir #2 is lagged behind that of the reservoir #1 by 3π/2, the pressure response in reservoir #1 is significantly enhanced with larger amplitude as well as phase angle. When the perturbations of the two reservoirs are out of phase, the heat effect is reduced and can become insignificant when the two perturbations are completely out of phase (ψ = π). Under such a condition, the pressure difference between the two reservoirs could be doubled. In the case of biporous pellets, it is shown that the FR behaviours obtained for micropore diffusion control and macropore diffusion control are well distinguished. In the former case, the FR system reduces to a traditional batch adsorber one while in the latter case, the FR behaviour is the same as for a two resonator system with homogeneous particles. This difference can be used for the discrimination of micropore and macropore diffusion processes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00879541
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 20
    Digitale Medien
    Digitale Medien
    Analysis of Diffusion in Hollow Geometries (2000)
    Springer
    Adsorption 6 (2000), S. 125-136 
    Details
    ISSN: 1572-8757
    Schlagwort(e): diffusion ; mathematical model ; analytical solution ; hollow material ; composite material ; mass transfer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract The diffusion in hollow particles of solid adsorbent materials was analyzed based on analytical solutions to the basic diffusion equation. Three geometric shapes (plane sheet, cylinder, and sphere) of sorbent material were considered for two kinds of boundary conditions. The equations for determining the equivalent sizes compared to their corresponding solid particles were obtained directly from the theoretical expressions of sorption uptake curves. Among the three hollow particles of impermeable inner surface, the sphere gives the highest gain in effective diffusion rate compared to the corresponding solid particle. For permeable inner surface, at lower hollow volume fractions, the plane sheet shows the highest gain, while at higher hollow volume fractions, the sphere shows the highest gain in effective diffusion rate.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008913301145
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 21
    Digitale Medien
    Digitale Medien
    A Symplectic Mapping Model as a Tool to Understand the Dynamics of 2/1 Resonant Asteroid Motion (1999)
    Springer
    Celestial mechanics and dynamical astronomy 73 (1999), S. 65-76 
    Details
    ISSN: 1572-9478
    Schlagwort(e): resonance ; chaotic motion ; diffusion ; secondary resonances
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We present a 3-D symplectic mapping model that is valid at the 2:1 mean motion resonance in the asteroid motion, in the Sun-Jupiter-asteroid model. This model is used to study the dynamics inside this resonance and several features of the system have been made clear. The introduction of the third dimension, through the inclination of the asteroid orbit, plays an important role in the evolution of the asteroid and the appearance of chaotic motion. Also, the existence of the secondary resonances is clearly shown and their role in the appearance of chaotic motion and the slow diffusion of the elements of the orbit is demonstrated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008378426081
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 22
    Digitale Medien
    Digitale Medien
    On the measure of the structure around the last kam torus before and after its break-up (1996)
    Springer
    Celestial mechanics and dynamical astronomy 64 (1996), S. 21-31 
    Details
    ISSN: 1572-9478
    Schlagwort(e): KAM tori ; diffusion ; symplectic maps ; standard map
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Using mappings as model problem we study the structure around the last invariant KAM torus for different values of the perturbing parameter. We used the standard map for the analysis of the hierarchical structure existing around invariant KAM tori applying two complementary methods: the Laskar's frequency map analysis and the sup-map analysis. We recover and extend the theoretical prediction recently given by Morbidelli and Giorgilli about the existence of a neighborhood almost completely full of slave tori around a chief torus. We then make tests about the diffusion in order to measure the barrier to diffusion which still remains after the break-up of the last KAM torus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00051602
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 23
    Digitale Medien
    Digitale Medien
    Instability and Diffusion in the Elliptic Restricted Three-body Problem (1998)
    Springer
    Celestial mechanics and dynamical astronomy 70 (1998), S. 23-39 
    Details
    ISSN: 1572-9478
    Schlagwort(e): resonant orbit ; transversal intersection ; resonant jump ; diffusion ; instability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The importance of the stability characteristics of the planar elliptic restricted three-body problem is that they offer insight about the general dynamical mechanisms causing instability in celestial mechanics. To analyze these concerns, elliptic–elliptic and hyperbolic–elliptic resonance orbits (periodic solutions with lower period) are numerically discovered by use of Newton's differential correction method. We find indications of stability for the elliptic–elliptic resonance orbits because slightly perturbed orbits define a corresponding two-dimensional invariant manifold on the Poincaré surface-section. For the resonance orbit of the hyperbolic–elliptic type, we show numerically that its stable and unstable manifolds intersect transversally in phase-space to induce instability. Then, we find indications that there are orbits which jump from one resonance zone to the next before escaping to infinity. This phenomenon is related to the so-called Arnold diffusion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008200806138
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 24
    Digitale Medien
    Digitale Medien
    Fundamental Study on Near-Axis Scattered Light and Its Application to Optical Computed Tomography (2000)
    Springer
    Optical review 7 (2000), S. 383-388 
    Details
    ISSN: 1349-9432
    Schlagwort(e): near-axis scattered light ; optical computed tomography ; time-resolved measurement ; scattering ; diffusion ; random media ; visibility ; photon migration ; computed tomography ; biomedical optics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract To find a basic principle of optical computed tomography (optical CT), a fundamental study was conducted on the use of scattered light in diffuse random media. We call the scattered light that propagates along the optical axis of the incident light beam near-axis scattered light (NASL). The use of NASL for the imaging through a diffuse medium was proposed and its basic characteristics were analyzed. The existence and measurability of NASL were confirmed in the simulation and measurement. To detect NASL efficiently, a technique called the scattering angle differential technique was developed. In CT imaging with a model phantom, the feasibility and effectiveness of the proposed technique were verified. We found that this technique alone was not sufficient to obtain the cross sectional image of an animal body, therefore a technique called the contact technique was devised to overcome the problems of reflection and refraction at the air-tissue interface. Finally, a prototype system was developed which integrated all the proposed techniques. With this system, we could obtain the CT images of a living mouse, in which the blood-rich organs such as liver and kidneys were clearly recognizable.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s10043-000-0383-4
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 25
    Digitale Medien
    Digitale Medien
    Sediment diffusive fluxes of Fe, Mn, and P in a eutrophic lake: Contribution from lateral vs bottom sediments (1996)
    Springer
    Aquatic sciences 58 (1996), S. 327-354 
    Details
    ISSN: 1420-9055
    Schlagwort(e): Iron ; manganese ; phosphate ; sediment ; diffusion ; eutrophic lake
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Water column data and porewater profiles are used to study the chemical evolution with time and with depth of a eutrophic lake. By using different approaches, diffusion fluxes for dissolved iron, manganese and phosphate are calculated and used to describe the processes occurring at the sediment-water interface as well as in the hypolimnion of the lake. These data are used in the elaboration of a qualitative model to describe the chemical behaviour of the sedimentary interface of an anoxic lake with emphasis on the Fe/P/S system. Acorona model is proposed to explain the evolution with time of the diffusion process by estimating the relative contribution of bottom and lateral sediment surfaces to the total fluxes of dissolved elements diffusing from the sediment to the overlying water. As the hypolimnion becomes more anoxic, it has been observed that lateral sediment surfaces (16 to 10 meters in depth) represents a larger supplier of diffusing dissolved components than the bottom sediment portion (bottom to 18 meters).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00877474
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 26
    Digitale Medien
    Digitale Medien
    Butterflies and ants: The communicative domain (1996)
    Springer
    Cellular and molecular life sciences 52 (1996), S. 14-24 
    Details
    ISSN: 1420-9071
    Schlagwort(e): Lycaenidae ; Formicidae ; symbiosis ; mutualism ; parasitism ; communication ; ecology ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Associations with ants, termed myrmecophily, are widespread in the butterfly family Lycaenidae and range from mere co-existence to more or less specific mutualistic or even parasitic interactions. Secretions of specialized epidermal glands are crucial for mediating the interactions. Transfer of nutrients (carbohydrates, amino acids) from butterfly larvae to ants plays a major role, but manipulative communication with the help of odour signals is also involved. By means of myrmecophily, lycaenid butterflies largely escape ant predation, and certain species gain protection through attendant ants or achieve developmental benefits from ant-attendance. Benefits to the ants range from minimal to substantial food rewards. While most lycaenid species maintain facultative relationships with a variety of ant genera, highly specific and obligatory associations have convergently evolved in a number of butterfly lineages. As a corollary, communication systems are largely unspecific in the former, but may be highly specialized in the latter. The sophisticated communication between obligate myrmecophiles and their host ants is tightly connected with the evolutionary rise of specialized life-cycles and thus is a source of augmenting diversity within the butterflies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01922410
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 27
    Digitale Medien
    Digitale Medien
    Quantitative genetics of zooplankton life histories (1995)
    Springer
    Cellular and molecular life sciences 51 (1995), S. 454-464 
    Details
    ISSN: 1420-9071
    Schlagwort(e): Quantitative genetics ; life history ; evolution ; cladocera ; heritability ; Daphnia ; zooplankton
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Quantitative genetic techniques are powerful tools for use in understanding the microevolutionary process. Because of their size, lifespan, and ease of culture, many zooplankton species are ideal for quantitative genetic approaches. As model systems, studies of zooplankton life histories are becoming increasingly used for examination of the central paradigms of evolutionary theory. Two of the fundamental empirical questions that zooplankton quantitative genetics studies can answer are: 1) How much genetic variance exists in natural populations for life history traits? 2) What is the empirical evidence for trade-offs that permeate life history theory based on optimality approaches? A review of existing data onDaphnia indicates substantial genetic variance for body size, clutch size, and age at first reproduction. Average broad-sense heritabilities for these three characters across 19 populations of 6 species are 0.31, 0.31, and 0.34, respectively. Although there is some discrepancy between the two pertinent studies that were designed to decompose the total genetic variance into its additive and non-additive components, a crude average seems to suggest that approximately 60% of the total genetic variance has an additive basis. The existing data are somewhat inconsistent with respect to presence/absence of trade-offs (negative genetic correlations) among life history traits. A composite of the existing data seems to argue against the existence of strong trade-offs between offspring size and offspring number, between present and future reproduction, and between developmental rate and fecundity. However, there is some evidence for a shift toward more negative (less positive) covariances in more stressful environments (e.g., low food). Zooplankton will prove to be very useful in future study in several important areas of research, including the genetics and physiology of aging, the importance of genotype-environment interaction for life history traits, and the evolution of phenotypic plasticity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02143198
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 28
    Digitale Medien
    Digitale Medien
    The accessory gland proteins in maleDrosophila: structural, reproductive, and evolutionary aspects (1996)
    Springer
    Cellular and molecular life sciences 52 (1996), S. 503-510 
    Details
    ISSN: 1420-9071
    Schlagwort(e): Drosophila ; accessory gland ; reproduction ; sexual behavior ; sperm displacement ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Recent results from biochemical and molecular genetic studies of the accessory gland proteins in maleDrosophila are reviewed. The most prominent feature is the species-specific variability. However, the analysis of the sex peptide inD. melanogaster shows that there is a strong homology in the molecular structure to the closely related sibling species, and that divergence increases with increasing phylogenetic distance. For this reason the sex peptide, after being transferred to the female genital tract during copulation, reduces receptivity and increases oviposition only in virgin females belonging to the same species group and subgroup. Even though studies were hitherto limited to a small number of the secretory components, it is evident that the accessory gland proteins play a key role in reproductive success of the fruit fly by changing female sexual behavior, supporting sperm transfer, storage and displacement. Thus, genes encoding the accessory gland proteins are apparently under strong evolutionary selection.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01969718
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 29
    Digitale Medien
    Digitale Medien
    Classification and evolution of EF-hand proteins (1998)
    Springer
    BioMetals 11 (1998), S. 277-295 
    Details
    ISSN: 1572-8773
    Schlagwort(e): evolution ; classification ; EF-hand ; domain ; homology ; chimera ; congruence ; gene duplication ; gene fusion ; eukaryote ; dendrogram ; calmodulin ; troponin C ; light chain of myosin ; S100 ; parvalbumin ; calcineurin ; recoverin ; calpain ; sorcin ; diacylglycerol ; calbindin ; aequorin ; phospholipase C ; BM-40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Forty-five distinct subfamilies of EF-hand proteins have been identified. They contain from two to eight EF-hands that are recognizable by amino acid sequence as being statistically similar to other EF-hand domains. All proteins within one subfamily are congruent to one another, i.e. the dendrogram computed from one of the EF-hand domains is similar, within statistical error, to the dendrogram computed from another(s) domain. Thirteen subfamilies - including Calmodulin, Troponin C, Essential light chain, Regulatory light chain - referred to collectively as CTER, are congruent with one another. They appear to have evolved from a single ur-domain by two cycles of gene duplication and fusion. The subfamilies of CTER subsequently evolved by gene duplications and speciations. The remaining 32 subfamilies do not show such general patterns of congruence; however, some - such as S100, intestinal calcium binding protein (calbindin 9kd), and trichohylin - do not form congruent clusters of subfamilies. Nearly all of the domains 1, 3, 5, and 7 are most similar to other ODD domains. Correspondingly the EVEN numbered domains of all 45 subfamilies most closely resemble EVEN domains of other subfamilies. Many sequence and chem-ical characteristics do not show systemic trends by subfamily or species of host organisms; such homoplasy is widespread. Eighteen of the subfamilies are heterochimeric; in addition to multiple EF-hands they contain domains of other evolutionary origins.© Kluwer Academic Publishers
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009282307967
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 30
    Digitale Medien
    Digitale Medien
    The Rectangular Isotherm Model for Adsorption Kinetics (2000)
    Springer
    Adsorption 6 (2000), S. 287-291 
    Details
    ISSN: 1572-8757
    Schlagwort(e): diffusion ; shrinking core ; rectangular isotherm
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract The transient uptake response of an adsorbent particle, subjected to a step change in surface concentration, is considered. It is shown that, when the isotherm is highly favorable, the theoretical curves derived for a Langmuirian system reduce asymptotically to the much simpler form for a rectangular isotherm. The simple rectangular model provides a useful approximation even when the form of the actual isotherm is quite far from the rectangular limit.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1026504730443
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 31
    Digitale Medien
    Digitale Medien
    Experience, Awareness and Consciousness:Suggestions for Definitions as Offered by an Evolutionary Approach (2000)
    Springer
    Foundations of science 5 (2000), S. 429-456 
    Details
    ISSN: 1572-8471
    Schlagwort(e): awareness ; reflexive awareness and consciousness ; evolution ; experience and pattern matching ; symbolic language
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Abstract An evolutionary point of view is proposed to make more appropriate distinctions between experience, awareness and consciousness. Experience can be defined as a characteristic linked closely to specific pattern matching, a characteristic already apparent at the molecular level at least. Awareness can be regarded as the special experience of one or more central, final modules in the animal neuronal brain. Awareness is what experience is to animals. Finally, consciousness could be defined as reflexive awareness. The ability for reflexive awareness is distinctly different from animal and human awareness and depends upon the availability of a separate frame of reference, as provided by symbolic language. As such, words have made reflexive awareness – a specific and infrequent form of awareness – possible. Conciousness might be defined as the experience evoked by considering, i.e. thinking about experiences themselves. If there is a hard problem of explaining consciousness, than this actually must be considered as the hard problem already met when trying to explain basic experience, since its nature remains elusive.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1011371811027
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 32
    Digitale Medien
    Digitale Medien
    A Study of Adsorption of Water Vapour on Wool under Static and Dynamic Conditions (1998)
    Springer
    Adsorption 4 (1998), S. 63-73 
    Details
    ISSN: 1572-8757
    Schlagwort(e): wool ; water vapour ; adsorption ; diffusion ; column dynamics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Adsorption of water vapour on wool provides not only textile comfort, but also convenience in transportation due to increase in its bulk density. The adsorption and desorption isotherms of water vapour for wool were determined by both volumetric technique using a Coulter Omnisorp 100CX instrument and gravimetric method employing a Cahn 2000 electronic microbalance. Adsorption isotherm fitting to B.E.T. model and hysteresis on desorption was observed. The average effective diffusion coefficient of water in wool was found to be 8.4 × 10-14 m2s-1 at 25°C from gravimetric data. The effects of packing height and air velocity on the breakthrough curves were also investigated in the wool packed columns. For pseudo first order model, k values changing between 0.33 × 10-6 − 69 × 10-6 s-1 was obtained for 2.2–6.4 cm s-1 air velocity and 0.05–0.20 m packing height ranges.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008839404382
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 33
    Digitale Medien
    Digitale Medien
    A Temperature Frequency Response Method for Adsorption Kinetics Measurements (1999)
    Springer
    Adsorption 5 (1999), S. 135-143 
    Details
    ISSN: 1572-8757
    Schlagwort(e): diffusion ; kinetics measurements ; frequency response ; NaX zeolite ; silicalite
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract A Frequency Response Method based on the infrared measurement of the sample temperature has been developed for adsorption kinetics measurements. It consists in modulating the experimental chamber volume at constant frequency. The complex ratio of the temperature response over the pressure response is independent of time but is a function of the frequency depending on all the kinetics parameters of the system. This method is accurate and allows to measure very fast kinetics. Its major drawback is that a spurious signal is observed at high pressure in absence of adsorption. The results obtained with silicalite-propane and NaX-carbon dioxide are compared with results obtained from other techniques (NMR, permeation, etc.).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008965223931
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 34
    Digitale Medien
    Digitale Medien
    Film Model Approximation for Multicomponent Adsorption (2000)
    Springer
    Adsorption 6 (2000), S. 5-13 
    Details
    ISSN: 1572-8757
    Schlagwort(e): multicomponent adsorption ; diffusion ; Maxwell-Stefan model ; linear driving force approximation ; Langmuir isotherm
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract An approximate rate equation based on a film-model representation of diffusional mass transfer is developed to describe the kinetics of multicomponent adsorption. The model describes mass transfer as a pseudo-steady state diffusion process through a flat film of thickness equal to one fifth of the particle radius. Starting with an irreversible thermodynamics description of multicomponent diffusion, the flux relationships are integrated across the film yielding analytical expressions for the rate of mass transfer in a multicomponent adsorption system, when adsorption equilibria are described by the extended Langmuir isotherm. The new approximate rate equation can be conveniently used in the numerical simulation of adsorption systems with concentration-dependent micropore or surface diffusivity, and describes the effects of diffusional flux coupling. Results of accuracy comparable with that obtained when using the classical linear-driving-force approximation for systems with constant diffusivities are obtained with this new rate equation for both batch and fixed-bed adsorption calculations. A generalization of the approach based on the Gibbs adsorption isotherm describes mass transfer rates in terms of the spreading-pressure gradient and provides an extension to other multicomponent isotherm forms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008927713530
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 35
    Digitale Medien
    Digitale Medien
    Colonization and evolution of lakes on the central Norwegian coast following deglaciation and land uplift 9500 to 7800 years B.P. (1997)
    Springer
    Journal of paleolimnology 18 (1997), S. 269-281 
    Details
    ISSN: 1573-0417
    Schlagwort(e): colonization ; evolution ; lakes ; Norway ; deglaciation ; land uplift ; invertebrates ; Chironomidae ; Porifera ; Bryozoa ; diatoms ; Charophyta ; tsunami
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie
    Notizen: Abstract Invertebrate colonization of lakes following the uplift of land from the sea was studied in four lakes, currently situated between 39 and 24 m a.s.l., on the central Norwegian coast. The lakes were isolated from the sea between 9500 and 7700 years B.P. Animal and algal remains picked from core samples showed that the first colonizers preserved as fossils were usually members of the Chironomidae, Daphnidae/Chydoridae, Acarina, Porifera (Ephydatia mülleri and Spongilla lacustris), Bryozoa (Cristatella mucedo and Plumatella spp.) and Charophyta (Chara sp.). Of the chironomids, the genus Chironomus was present in the oldest lacustrine layers of all four lakes, but other genera recorded at the marine/lacustrine boundary were Dicrotendipes, Procladius (?), Einfeldia, Microtendipes, and Glyptotendipes. Remains of the caddis fly family Limnephilidae were also present in the earliest lacustrine sediments in Kvennavatnet and Kvernavatnet. The oldest invertebrate fauna is typical for mesotrophic lakes. However, chironomids and mites have been present in this area from at least about 10 500 years B.P. A diverse chironomid community was established between 300 and 800 years after isolation from the sea at Kvernavatnet on the island of Hitra, while only between 80 and 120 years passed before a comparably diverse community developed at Kvennavatnet on the mainland coast. A similar development of the invertebrate fauna occurred in Kvennavatnet, Kvernavatnet and Storkuvatnet. However, Litjvatnet deviates greatly from the ‘normal’ pattern because a tsunami disturbed the bottom sediments and fauna. The tsunami, a gigantic sea wave, was caused by a submarine slide from the Norwegian continental slope. It reached Litjvatnet, today located 24 m a.s.l., but was not traced in Storkuvatnet at 30 m a.s.l. This event happened about 7200 years B.P.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007934825272
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 36
    Digitale Medien
    Digitale Medien
    Metals and models: Diagenic modelling in freshwater lacustrine sediments (1999)
    Springer
    Journal of paleolimnology 22 (1999), S. 227-251 
    Details
    ISSN: 1573-0417
    Schlagwort(e): diagenesis ; models ; metals ; porewater ; diffusion ; bioturbation ; irrigation ; remobilization ; iron ; manganese ; concretions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie
    Notizen: Abstract This review aims to distill and synthesize the existing information on the use of models to describe and predict the distribution and movement of metals in lacustrine sediments. As such it examines the causes of metal diagenesis, the origin and form of the equations that govern these phenomena, and the predictability or measurability of the parameters that appear in the models. The paper concludes by highlighting some seminal results from modelling studies, including the determination of the factors controlling the formation of surficial Mn-Fe-enriched zone or layers, the substantial contribution possible from metal reduction to organic matter regeneration, the calculation of mixing-corrected metal input histories to lakes, and the prediction of growth rates and morphologies for both deep-sea and lacustrine ferromanganese nodules.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008144029134
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 37
    Digitale Medien
    Digitale Medien
    Experimental and theoretical determination of concentration profiles and influence of particle characteristics in blowing snow (1995)
    Springer
    Surveys in geophysics 16 (1995), S. 695-710 
    Details
    ISSN: 1573-0956
    Schlagwort(e): Blowing snow ; airborne particles ; saltation ; diffusion ; image processing ; concentration profile ; fall velocity ; threshold friction velocity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Snow drift transport may cause avalanches on the roads during the periods of snowfall and strong wind. To better understand the factors influencing transport we have developed a theoretical model. This model is based on the boundary layer theory, where the particle mass conservation is considered. Assuming that the saturation is reached, the concentration profile can be represented by a negative exponential law. By means of this analysis, the influence of particle characteristics is explored through the roles of threshold friction velocity and fall velocity. Using fluid mechanics laws, an analysis of the concentration profile resulting from the effect of the wind on a particle bed was also developed. For several velocities of flow and for different kinds of particles an experimental determination of the concentration profile was achieved. We used a laser visualisation and image processing technique to carry out these experiments. The obtained results fit with the values predicted by the theoretical model.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00665749
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 38
    Digitale Medien
    Digitale Medien
    Modeling Atmospheric Chemistry: Interactions between Gas-Phase Species and Liquid Cloud/Aerosol Particles (1999)
    Springer
    Surveys in geophysics 20 (1999), S. 1-31 
    Details
    ISSN: 1573-0956
    Schlagwort(e): heterogeneous atmospheric chemistry ; chemistry ; Henry′s law ; accommodation coefficient ; cloud droplet ; aerosol particle ; solubility ; volatility ; diffusion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract For detailed modeling of atmospheric chemistry it is necessary to consider aqueous-phase reactions in cloud droplets and deliquesced aerosol particles. Often, the gas-phase concentration is in equilibrium with the aqueous phase. Then Henry′s law can be used to describe the distribution between the phases provided that the Henry′s law coefficient is known. In some cases, thermodynamic equilibrium will not be reached and it is necessary to use kinetic expressions of the rates involved. These rates depend on diffusion constants, accommodation coefficients, Henry′s law coefficients, particle size distributions, and several other parameters. This review describes how these processes can be treated in computer modeling and how the necessary data can be obtained. Even though it is written primarily for use in modeling atmospheric chemistry, some parts will also be useful for waste water and pesticide control and in other areas where the distribution of chemicals between the aqueous and the gas phase is important.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006501706704
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 39
    Digitale Medien
    Digitale Medien
    Evolution of novel metabolic pathways for the degradation of chloroaromatic compounds (1997)
    Springer
    Antonie van Leeuwenhoek 71 (1997), S. 159-178 
    Details
    ISSN: 1572-9699
    Schlagwort(e): aromatic pathways ; chlorobenzenes ; evolution ; genes ; plasmids ; pseudomonas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Chlorobenzenes are substrates not easily metabolized by existing bacteria in the environment. Specific strains, however, have been isolated from polluted environments or in laboratory selection procedures that use chlorobenzenes as their sole carbon and energy source. Genetic analysis indicated that these bacteria have acquired a novel combination of previously existing genes. One of these gene clusters contains the genes for an aromatic ring dioxy-genase and a dihydrodiol dehydrogenase. The other contains the genes for a chlorocatechol oxidative pathway. Comparison of such gene clusters with those from other aromatics degrading bacteria reveals that this process of recombining or assembly of existing genetic material must have occurred in many of them. Similarities of gene functions between pathways suggest that incorporation of existing genetic material has been the most important mechanism of expanding a metabolic pathway. Only in a few cases a horizontal expansion, that is acqui sition of gene functions to accomodate a wider range of substrates which are then all transformed in one central pathway, is observed on the genetic level. Evidence is presented indicating that the assembly process may trigger a faster divergence of nearby gene sequences. Further ‘fine-tuning’, for example by developing a proper regulation, is then the next step in the adaptation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1000166400935
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 40
    Digitale Medien
    Digitale Medien
    Evolution of bacterial genomes (1997)
    Springer
    Antonie van Leeuwenhoek 71 (1997), S. 265-270 
    Details
    ISSN: 1572-9699
    Schlagwort(e): bacteria ; DNA ; evolution ; genome ; RNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This review examines evolution of bacterial genomes with an emphasis on RNA based life, the transition to functional DNA and small evolving genomes (possibly plasmids) that led to larger, functional bacterial genomes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1000123216769
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 41
    Digitale Medien
    Digitale Medien
    Bacterial evolution and metabolism (1997)
    Springer
    Antonie van Leeuwenhoek 71 (1997), S. 257-263 
    Details
    ISSN: 1572-9699
    Schlagwort(e): bacteria ; energy ; evolution ; genome ; metabolism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This article examines the relationship between (or dependence of) bacterial evolution in prokaryotes and metabolism, and the changing physical-chemical conditions present during early evolution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1000175217677
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 42
    Digitale Medien
    Digitale Medien
    Molecular evolution in bacteria: Surfaces, cathodes and anodes (1997)
    Springer
    Antonie van Leeuwenhoek 71 (1997), S. 363-368 
    Details
    ISSN: 1572-9699
    Schlagwort(e): assembly ; anode ; bacteria ; cathode ; DNA ; evolution ; genetics ; molecular ; surfaces
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Molecular evolution is examined in bacteria with an emphasis on mineral surfaces, membranes, cathodes and anodes. In early molecular evolution, cathode-anode system may have been naturally occurring on a nm to µm scale. Secondly, the cathode-anode system could have been separated by a primitive, permeable lipid or microsphere on a mineral surface, that was a precursor of a more advanced membrane with a charge differential on either side of the membrane. These aspects will be considered from a theoretical evolutionary perspective.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1000271219036
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 43
    Digitale Medien
    Digitale Medien
    Molecular evolution and optimization (1997)
    Springer
    Antonie van Leeuwenhoek 72 (1997), S. 251-259 
    Details
    ISSN: 1572-9699
    Schlagwort(e): bacteria ; catalysis ; DNA ; enzyme ; evolution ; microorganisms ; optimization ; RNA ; time
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Microbial populations (and life) not only evolve, they optimize. The transition from a random, unorganized, lifeless Earth to the present situation, where the Earth is virtually covered with nucleic acids and diverse and complex species, required numerous molecular changes and the integration of metabolic pathways over billions of years. Primitive prokaryotic life was dependent on and constrained by the physical-chemical conditions on the Earth, while slowly reshaping conditions present. In this review, molecular evolution and molecular optimization are examined with an emphasis on the order in which evolutionary events occurred.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1000456825081
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 44
    Digitale Medien
    Digitale Medien
    Anomalous biennial oscillations in a Fisher equation with a discretized verhulst term (1995)
    Springer
    Journal of statistical physics 81 (1995), S. 761-775 
    Details
    ISSN: 1572-9613
    Schlagwort(e): Logistic map ; diffusion ; Fisher equation ; chaos ; oscillations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The dynamics of a biological population governed by a modified Fisher equation is studied by means of Monte Carlo simulations. Reproduction of the population occurs at discrete times, while transport caused by diffusion and conduction takes place on shorter time scales. The discrete reproduction, modeled with a set of coupled logistic maps, exhibits phenomena which are not evident in the usual continuum version of the Fisher equation. Several mechanisms for biennial oscillations of the total population are investigated. One of these shows an ordered coupling between random diffusive motion and the chaotic attractor of the logistic map.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02179256
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 45
    Digitale Medien
    Digitale Medien
    The long-time behavior of initially separated A+B→0 reaction-diffusion systems with arbitrary diffusion constants (1996)
    Springer
    Journal of statistical physics 85 (1996), S. 179-191 
    Details
    ISSN: 1572-9613
    Schlagwort(e): Reaction kinetics ; diffusion ; segregation ; partial differential equations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We examine the long-time behavior of A+B→0 reaction-diffusion systems with initially segregated species A and B. All of our analysis is carried out for arbitrary (positive) values of the diffusion constantsD A andD B and initial concentrationsa 0 andb 0 of A's and B's. We divide the domain of the partial differential equations describing the problem into several regions in which they can be reduced to simpler, solvable equations, and we merge the solutions. Thus we derive general formulas for the concentration profiles outside the reaction zone, the location of the reaction zone center, and the total reaction rate. An asymptotic condition for the reaction front to be stationary is also derived. The properties of the reaction layer are studied in the mean-field approximation, and we show that not only the scaling exponents, but also the scaling functions are independent ofD A,D B,a 0 andb 0.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02175561
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 46
    Digitale Medien
    Digitale Medien
    Periodic one-dimensional hopping model with one mobile directional impurity (1997)
    Springer
    Journal of statistical physics 87 (1997), S. 545-575 
    Details
    ISSN: 1572-9613
    Schlagwort(e): Random hopping model ; bond impurity ; diffusion ; asymmetric exclusion process ; electrophoresis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Analytic solution is given in the steady-state limitt→∞ for the system of master equations describing a random walk on one-dimensional periodic lattices with arbitrary hopping rates containing one mobile directional impurity (defect bond). Due to the defect, translational invariance is broken, even if all other rates are identical. The structure of master equations leads naturally to the introduction of a new entity, associated with the walker-impurity pair which we call the quasiwalker. The velocities and diffusion constants for both the random walker and impurity are given, being simply related to that of the quasiparticle through physically meaningful equations. Applications in driven diffusive systems are shown, and connections with the Duke-Rubinstein reptation models for gel electrophoresis are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02181236
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 47
    Digitale Medien
    Digitale Medien
    A Diffusion Equation from the Relativistic Ornstein–Uhlenbeck Process (1998)
    Springer
    Journal of statistical physics 90 (1998), S. 1179-1199 
    Details
    ISSN: 1572-9613
    Schlagwort(e): Irreversibility ; relativistic Ornstein–Uhlenbeck process ; relativistic statistical physics ; diffusion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We derive, in the “hydrodynamic” limit (large space and time scales), an evolution equation for the particle density in physical space from the (special) relativistic Ornstein–Uhlenbeck process introduced by Debbasch, Mallick, and Rivet. This equation turns out to be identical with the classical diffusion equation, without any relativistic correction. We prove that, in the “hydrodynamic” limit, this result is indeed compatible with special relativity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1023275210656
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 48
    Digitale Medien
    Digitale Medien
    Diffusion Lattice Boltzmann Scheme on a Orthorhombic Lattice (1999)
    Springer
    Journal of statistical physics 94 (1999), S. 203-217 
    Details
    ISSN: 1572-9613
    Schlagwort(e): lattice Boltzmann ; diffusion ; eigenmode analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We present a diffusion lattice Boltzmann (DLB) scheme which is derived from first principles. As opposed to the traditional lattice BGK schemes the DLB is valid for orthorhombic lattices and it has two eigenvalues of the collision operator. It is shown that the diffusion coefficient depends only on one eigenvalue of the collision operator. Hence, the DLB scheme can be optimized with means of the additional eigenvalue of the collision operator and with different lattice spacing along the principal axes. The properties of the DLB scheme concerning consistency, stability, and accuracy are studied with eigenmode analysis. This analysis shows that the DLB scheme is consistent with diffusion for a wide range of diffusion coefficients, it has unconditional stability, and that it has third-order accuracy. Furthermore, it is shown that accuracy is improved by setting the additional eigenvalue to zero and by densifying the lattice spacing along the direction of the density gradient.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004515413793
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 49
    Digitale Medien
    Digitale Medien
    Effective Potential for the Reaction-Diffusion-Decay System (2000)
    Springer
    Journal of statistical physics 99 (2000), S. 903-941 
    Details
    ISSN: 1572-9613
    Schlagwort(e): effective potential ; reaction ; diffusion ; decay
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract In previous work we have developed a general method for casting stochastic partial differential equations (SPDEs) into a functional integral formalism, and have derived the one-loop effective potential for these systems. In this paper we apply the same formalism to a specific field theory of considerable interest, the reaction-diffusion-decay system. When this field theory is subject to white noise we can calculate the one-loop effective potential (for arbitrary polynomial reaction kinetics) and show that it is one-loop ultraviolet renormalizable in 1, 2, and 3 space dimensions. For specific choices of interaction terms the one-loop renormalizability can be extended to higher dimensions. We also show how to include the effects of fluctuations in the study of pattern formation away from equilibrium, and conclude that noise affects the stability of the system in a way which is calculable.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1018699630306
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 50
    Digitale Medien
    Digitale Medien
    A survey of equid mitochondrial DNA: Implications for the evolution, genetic diversity and conservation of Equus (2000)
    Springer
    Conservation genetics 1 (2000), S. 341-355 
    Details
    ISSN: 1572-9737
    Schlagwort(e): conservation genetics ; Equus ; evolution ; mitochondrial DNA control region ; mitochondrial 12S rRNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The evolution, taxonomy and conservation of the genus Equuswere investigated by examining the mitochondrial DNA sequences of thecontrol region and 12S rRNA gene. The phylogenetic analysis of thesesequences provides further evidence that the deepest node in thephylogeny of the extant species is a divergence between twolineages; one leading to the ancestor of modern horses (E.ferus, domestic and przewalskii) and the other to thezebra and ass ancestor, with the later speciation events of the zebrasand asses occurring either as one or more rapid radiations, or withextensive secondary contact after speciation. Examination of the geneticdiversity within species suggested that two of the E. hemionussubspecies (E. h. onager and E. h. kulan) onlyrecently diverged, and perhaps, are insufficiently different to beclassified as separate subspecies. The genetic divergence betweendomestic and wild forms of E. ferus (horse) and E.africanus (African ass) was no greater than expected within anequid species. In E. burchelli (plains zebra) there was anindication of mtDNA divergence between populations increasing withdistance. The implications of these results for equid conservation arediscussed and recommendations are made for conservation action.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1011559200897
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 51
    Digitale Medien
    Digitale Medien
    Robert Chambers and Thomas Henry Huxley, Science Correspondents: The Popularization and Dissemination of Nineteenth Century Natural Science (1999)
    Springer
    Journal of the history of biology 32 (1999), S. 343-383 
    Details
    ISSN: 1573-0387
    Schlagwort(e): agnosticism ; Darwinian ; evolution ; materialism ; Malthusian ; nebular hypothesis ; popularization ; professionalization ; transitional forms
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geschichte
    Notizen: Abstract Robert Chambers and Thomas Henry Huxley helped popularize science by writing for general interest publications when science was becoming increasingly professionalized. A non-professional, Chambers used his family-owned Chambers' Edinburgh Journal to report on scientific discoveries, giving his audience access to ideas that were only available to scientists who regularly attended professional meetings or read published transactions of such forums. He had no formal training in the sciences and little interest in advancing the professional status of scientists; his course of action was determined by his disability and interest in scientific phenomena. His skillful reporting enabled readers to learn how the ideas that flowed from scientific innovation affected their lives, and his series of article in the Journal presenting his rudimentary ideas on evolution, served as a prelude to his important popular work, Vestiges of the Natural History of Creation. Huxley, an example of the new professional class of scientists, defended science and evolution from attacks by religious spokesmen and other opponents of evolution, informing the British public about science through his lectures and articles in such publications as Nineteenth Century. He understood that by popularizing scientific information, he could effectively challenge the old Tory establishment -- with its orthodox religious and political views -- and promote the ideas of the new class of professional scientists. In attempting to transform British society, he frequently came in conflict with theologians and others on issues in which science and religion seemed to contradict each other but refused to discuss matters of science with non-professionals like Chambers, whose popular writing struck a more resonant chord with working class readers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004616403134
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 52
    Digitale Medien
    Digitale Medien
    Last Judgment: The Visionary Biology of J. B. S. Haldane (2000)
    Springer
    Journal of the history of biology 33 (2000), S. 457-491 
    Details
    ISSN: 1573-0387
    Schlagwort(e): J. B. S. Haldane ; biology ; politics ; genetics ; evolution ; population genetics ; physiology ; Darwinism ; experimental biology ; eugenics ; Britain ; Russia ; India ; Soviet ; Communism ; socialism ; philosophy ; vision ; literature ; popularization ; religion ; human experimentation ; bioethics ; Venus ; Mars ; science fiction ; technocracy ; futurology ; H. G. Wells ; Julian Huxley ; Olaf Stapledon ; C. S. Lewis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geschichte
    Notizen: Abstract This paper seeks to reinterpret the life and work of J. B. S. Haldane by focusing on an illuminating but largely ignored essay he published in1927, “The Last Judgment” – the sequel to his better known work, Daedalus (1924). This astonishing essay expresses a vision of the human future over the next 40,000,000 years, one that revises and updates Wellsian futurism with the long range implications of the “new biology” for human destiny. That vision served as a kind of lifelong credo, one that infused and informed his diverse scientific work, political activities, and popular writing, and that gave unity and coherence to his remarkable career.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004891323595
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 53
    Digitale Medien
    Digitale Medien
    Sex, Death, and Evolution in Proto- and Metazoa, 1876–1913 (2000)
    Springer
    Journal of the history of biology 33 (2000), S. 221-246 
    Details
    ISSN: 1573-0387
    Schlagwort(e): August Weismann ; ciliates ; Clifford Dobell ; cytology ; death ; Emile Maupas ; evolution ; Herbert Spencer Jennings ; Otto Bütschli ; Paramecium ; rejuvenescence ; sex
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geschichte
    Notizen: Abstract In the period 1875–1920, a debate about the generality and applicability of evolutionary theory to all organisms was motivated by work on unicellular ciliates like Paramecium because of their peculiar nuclear dualism and life cycles. The French cytologist Emile Maupas and the German zoologist August Weismann argued in the 1880s about the evolutionary origins and functions of sex (which in the ciliates is not linked to reproduction), and death (which appeared to be the inevitable fate of lineages denied sexual conjugation), an argument rooted in the question of whether the ciliates and their processes where homologous to other cellular organisms. In the beginning of the twentieth century, this question of homology came to be less important as the ciliates were used by the British protozoologist Clifford Dobell and the American zoologist Herbert Spencer Jennings to study evolutionary processes in general rather than problems of development and cytology. For them, homology mattered less than analogy. This story illustrates two partially distinct problems in evolutionary biology: first, the question of whether all living things have common features and origins; and second, whether their history and current nature can be described by identical mechanisms. Where Maupas (contra Weismann) made the ciliates qualitatively the same as all other organisms in order to create a cohesive evolutionary theory for biology, Jennings and Dobell made them qualitatively different in order to achieve the same end.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004740325150
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 54
    Digitale Medien
    Digitale Medien
    On the elevated intestinal pH of higher termites (Isoptera: Termitidae) (1995)
    Springer
    Insectes sociaux 42 (1995), S. 57-69 
    Details
    ISSN: 1420-9098
    Schlagwort(e): Hindgut ; alkalinity ; evolution ; symbionts ; gut morphology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The pH of the gut contents was measured in 52 species of higher termites (Termitidae), representing 36 genera in all four subfamilies. A statistically significant trend was shown from lower termites with low mean gut pH through to the Termitinae with higher mean gut pHs. Elevation of the pH occurred principally in the first and third proctodaeal segments, reaching values as high as 10.5 in 8 soil-feeding genera and 1 wood-feeding genus of Termitinae. Elevation of gut pH within the Termitidae appears to be independent of the general nature of the feeding substrate.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01245699
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 55
    Digitale Medien
    Digitale Medien
    Castes in humivorous and litter-dwelling neotropical nasute termites (Isoptera, Termitidae) (1996)
    Springer
    Insectes sociaux 43 (1996), S. 375-389 
    Details
    ISSN: 1420-9098
    Schlagwort(e): Nasutitermitinae ; Subulitermes ; Coatitermes ; Velocitermes ; evolution ; phylogeny
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The developmental pathways of the neuter castes were studied in three species of Nasutitermitinae from central Panama. The humivorousSubulitermes denisae andCoatitermes clevelandi display several primitive traits: absence of sex dimorphism, representation of both sexes among workers and soldiers, and occurrence of successive worker instars. The litter-dwellingVelocitermes barrocoloradensis has a more complex caste system: female larvae are larger than males and give rise to the large workers, which constitute the bulk of the work force; male larvae proceed to soldiers through a small worker or a special larval instar. The resulting soldier caste is polymorphic. These results support previously formulated hypotheses regarding a link between humivorous diet and reduced polymorphism on the one hand, and between forest-floor foraging and large continuous size variation among soldiers on the other. Whereas the caste systems ofSubulitermes andCoatitermes probably represent a primitive condition,Velocitermes shares derived traits withNasutitermes and the other fully nasute genera previously studied. I therefore hypothesize that ancestors with these advanced features may have spread from the neotropics and be at the origin of most nasute genera, including humivorous taxa, present in other regions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01258410
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 56
    Digitale Medien
    Digitale Medien
    Sequence comparisons of the internal transcribed spacer region of ribosomal genes support close relationships between parasitic ants and their respective host species (Hymenoptera: Formicidae) (1996)
    Springer
    Insectes sociaux 43 (1996), S. 53-67 
    Details
    ISSN: 1420-9098
    Schlagwort(e): Formicidae ; Leptothoracini ; Tetramoriini ; internal transcribed spacer ; social parasitism ; evolution ; phylogenetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A fragment of the internal transcribed spacer (ITS-1) adjacent to the 5.8S rRNA gene of 20 myrmicine ant species was sequenced. Sequence comparisons were carried out between 11 species of the tribe Leptothoracini, five species of the tribe Tetramoriini, three species of the tribe Solenopsidini and one species of the tribe Myrmicini. Additionally, the formicine antCamponotus ligniperda (tribe Camponotini) was analyzed as an outgroup species. Among all investigated species, the fragment had a variable length of ≈ 230–380 bp with only a few conserved sequence elements. The sequences of this fragment were perfectly identical within four palearctic populations ofLeptothorax acervorum indicating that intraspecific variation is rather low. Within the species of Tetramoriini (includingAnergates atratulus) 94.1% of sequence positions were identical, 95.6% within the species of theLeptothorax s.str.-group and 64.6% within the species of theMyrafant-group. Phylogenetic analysis reveals that the social parasitesHarpagoxenus sublaevis, Doronomyrmex goesswaldi, D. kutteri andD. pacis, Chalepoxenus muellerianus as well asStrongylognathus alpinus andTeleutomyrmex schneideri are most closely related to the groups of their respective host species, which generally confirms the taxonomical classifications of the subfamily Myrmicinae based on morphological criteria. The taxonomical positions of the speciesA. atratulus has as yet been uncertain, however, sequence comparison of the ITS-1 fragment leads to the conclusion thatA. atratulus rather belongs to the tribe Tetramoriini than to the Solenopsidini.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01253956
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 57
    Digitale Medien
    Digitale Medien
    Sex pheromones and attractants in the Eucosmini and Grapholitini (Lepidoptera, Tortricidae) (1996)
    Springer
    Chemoecology 7 (1996), S. 13-23 
    Details
    ISSN: 1423-0445
    Schlagwort(e): sex pheromone ; synergist ; antagonist ; mate recognition ; reproductive isolation ; chemotaxonomoy ; phylogeny ; evolution ; Lepidoptera ; Tortricidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The geometric isomers (E,E)-, (E,Z)-, (Z,E)-, and (Z,Z)-8,10-dodecadien-1-yl acetate were identified as sex pheromone components or sex attractants in the tribes Eucosmini and Grapholitini of the tortricid subfamily Olethreutinae. Species belonging to the more ancestral Tortricinae were not attracted. Each one isomer was behaviourally active in males ofCydia andGrapholita (Grapholitini), either as main pheromone compound, attraction synergist or attraction inhibitor. Their reciprocal attractive/antagonistic activity in a number of species enables specific communication with these four compounds.Pammene, as well as otherGrapholita andCydia responded to the monoenic 8- or 10-dodecen-1-yl acetates. Of the tribes Olethreutini and Eucosmini,Hedya, Epiblema, Eucosma, andNotocelia trimaculana were also attracted to 8,10-dodecadien-1-yl acetates, but several otherNotocelia to 10,12-tetradecadien-1-yl acetates. The female sex pheromones ofC. fagiglandana, C. pyrivora, C. splendana, Epiblema foenella andNotocelia roborana were identified. (E,E)- and (E,Z)-8,10-dodecadien-1-yl acetate are producedvia a commonE9 desaturation pathway inC. splendana. CallingC. nigricana andC. fagiglandana females are attracted to wingfanning males.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01240633
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 58
    Digitale Medien
    Digitale Medien
    Evidence for an HLA-C-like locus in the orangutan Pongo pygmaeus (1999)
    Springer
    Immunogenetics 49 (1999), S. 865-871 
    Details
    ISSN: 1432-1211
    Schlagwort(e): Key words Orangutan ; MHC class I ; HLA-C ; natural killer cells ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  HLA-B and C are related class I genes which are believed to have arisen by duplication of a common ancestor. Previous study showed the presence of orthologues for both HLA-B and C in African apes but only for HLA-B in Asian apes. These observations suggested that the primate C locus evolved subsequent to the divergence of the Pongidae and Hominidae. From an analysis of orangutan Tengku two HLA-C-like alleles (Popy C*0101 and Popy C*0201) were defined as well as three HLA-B-like (Popy-B) alleles. By contrast, no Popy-C alleles were obtained from orangutan Hati, although three Popy-B alleles were defined. Thus an HLA-C-like locus exists in the orangutan (as well as a duplicated B locus), implying that the primate C locus evolved prior to the divergence of the Pongidae and Hominidae and is at least 12–13 million years old. Uncertain is whether all orangutan MHC haplotypes contain a C locus, as the failure to find C alleles in some individuals could be due to a mispairing of HLA-C-specific primers with certain Popy-C alleles. These results raise the possibilities that other primate species have a C locus and that the regulation of natural killer cells by C allotypes evolved earlier in primate evolution than has been thought.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002510050566
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 59
    Digitale Medien
    Digitale Medien
    Fluctuation of body temperature and cuckoo brood parasitism (1995)
    Springer
    Ecological research 10 (1995), S. 321-325 
    Details
    ISSN: 1440-1703
    Schlagwort(e): body temperature ; brood parasitism ; cuckoo ; evolution ; telemetry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Body temperatures of 11 bird species, including cuckoos, were measured in an artificial meteorological room. Ratios of change in body temperature to that in air temperature were thereby obtained for each species. Cuckoos demonstrate a remarkably high value, indicating a particularly low ability to regulate body temperature. Viewed in this light, the cuckoo's parasitic behavior is very likely an adaptation to overcome a physiological disadvantage. This in turn might be expected to reinforce delay in evolution of temperature homeostasis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02347858
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 60
    Digitale Medien
    Digitale Medien
    The ecology and evolution of bacteriocins (1996)
    Springer
    Journal of industrial microbiology and biotechnology 17 (1996), S. 151-158 
    Details
    ISSN: 1476-5535
    Schlagwort(e): bacteriocins ; colicins ; evolution ; ecology ; Escherichia coli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract In this review we focus on the ecological and evolutionary forces that determine the frequency and diversity of colicins inEscherichia coli. To begin, we describe that this killing phenotype is ubiquitous inE. coli, with as many as 50% of the isolates from a population producing colicin toxins, and that each population sampled has its own unique distribution of the more than 20 known colicin types. Next, we explore the dynamics of colicinogeny, which exhibits a typical form of frequency dependence, where the likelihood of successful colicin invasion into a population increases as the initial density of colicinogenic cells increases. We then incorporate thoughts on the evolution of chromosomal resistance to colicins and describe how resistance might influence the dynamics of colicinogen invasion and maintenance and the resulting colicin diversity. The final section deals with a genetic and phylogenetic characterization of colicins and a discussion of the evolutionary mechanisms responsible for generating colicin diversity. In this final section we provide details of the different molecular mechanisms known to play a role in generating colicin diversity, including the two most dominant forces in colincin evolution: recombination and positive, deversifying, selection.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01574688
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 61
    Digitale Medien
    Digitale Medien
    Dynamic Light Scattering Measurement of Nanometer Particles in Liquids (2000)
    Springer
    Journal of nanoparticle research 2 (2000), S. 123-131 
    Details
    ISSN: 1572-896X
    Schlagwort(e): nanoparticle ; characterization ; light scattering ; PCS ; interferometry ; diffusion ; polydispersivity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik , Technik allgemein
    Notizen: Abstract Dynamic light scattering (DLS) techniques for studying sizes and shapes of nanoparticles in liquids are reviewed. In photon correlation spectroscopy (PCS), the time fluctuations in the intensity of light scattered by the particle dispersion are monitored. For dilute dispersions of spherical nanoparticles, the decay rate of the time autocorrelation function of these intensity fluctuations is used to directly measure the particle translational diffusion coefficient, which is in turn related to the particle hydrodynamic radius. For a spherical particle, the hydrodynamic radius is essentially the same as the geometric particle radius (including any possible solvation layers). PCS is one of the most commonly used methods for measuring radii of submicron size particles in liquid dispersions. Depolarized Fabry-Perot interferometry (FPI) is a less common dynamic light scattering technique that is applicable to optically anisotropic nanoparticles. In FPI the frequency broadening of laser light scattered by the particles is analyzed. This broadening is proportional to the particle rotational diffusion coefficient, which is in turn related to the particle dimensions. The translational diffusion coefficient measured by PCS and the rotational diffusion coefficient measured by depolarized FPI may be combined to obtain the dimensions of non-spherical particles. DLS studies of liquid dispersions of nanometer-sized oligonucleotides in a water-based buffer are used as examples.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010067107182
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 62
    Digitale Medien
    Digitale Medien
    The Glycophorin A Gene Family in Gorillas: Structure, Expression, and Comparison with the Human and Chimpanzee Homologues (1997)
    Springer
    Biochemical genetics 35 (1997), S. 59-76 
    Details
    ISSN: 1573-4927
    Schlagwort(e): glycophorins ; gorilla ; evolution ; gene family ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Homologues of MN blood group antigens, encoded by members of the glycophorin A (GPA) gene family, are expressed in man, anthropoid apes, and some species of Old World monkeys. Previous studies had shown that a three-gene framework, most closely related to that in man, is present in the chimpanzee. Here we report the genomic structure, transcript map, and protein expression of the GYPA locus in gorillas. Compared to the corresponding human and chimpanzee homologues, gorilla GPA, GPB, and GPB/E genes each showed a high degree of sequence identity, with the same exon-intron organization. However, the expression of exons III, IV, or V encoding the extracellular or membrane domains of homologous glycophorins varied among the three species. Gorilla GPA and GPB/E genes were unique in that the former occurred in two allelic forms with or without the expression of exon III, whereas the latter contained one (ψ exon III) instead of two silenced exons (ψ exons III and IV). Differences from human but not chimpanzee GPA also included the presence of a hybrid M/N epitope and the absence of the sequon for N-glycosylation. Owing to the retention of a functional exon III, gorilla GPB was more similar to chimpanzee GPB than human GPB. A transspecies allele was identified in the gorilla that gave rise to the Henshaw (He)-like antigen similar to that found in man. These results provide further insight into the model for evolution of the GPA gene family, indicating that the mechanisms underlying inter- and intraspecific polymorphism of glycophorins could predate the divergence of gorillas as the consequence of gene duplication and diversification.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022212630370
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 63
    Digitale Medien
    Digitale Medien
    A theoretical model of some spatial and temporal aspects of the mitochondrion creatine kinase myofibril system in muscle (1997)
    Springer
    Molecular and cellular biochemistry 174 (1997), S. 29-32 
    Details
    ISSN: 1573-4919
    Schlagwort(e): adenine nucleotide translocase ; creatine kinase ; diffusion ; mitochondrion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract We describe a model of mitochondrial regulation in vivo which takes account of spatial diffusion of high-energy (ATP and phosphocreatine) and low-energy metabolites (ADP and creatine), their interconversion by creatine kinase (which is not assumed to be at equilibrium), and possible functional 'coupling' between the components of creatine kinase associated with the mitochondrial adenine nucleotide translocase and the myofibrillar ATPase. At high creatine kinase activity, the degree of functional coupling at either the mitochondrial or ATPase end has little effect on relationships between oxidative ATP synthesis rate and spatially-averaged metabolite concentrations. However, lowering the creatine kinase activity raises the mean steady state ADP and creatine concentrations, to a degree which depends on the degree of coupling. At high creatine kinase activity, the fraction of flow carried by ATP is small. Lowering the creatine kinase activity raises this fraction, especially when there is little functional coupling. All metabolites show small spatial gradients, more so at low cytosolic creatine kinase activity, and unless there is near-complete coupling, so does net creatine kinase flux. During workjump transitions, spatial-average responses exhibit near-exponential kinetics as expected, while concentration changes start at the ATPase end and propagate towards the mitochondrion, damped in time and space. (Mol Cell Biochem 174: 29–32, 1997)
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006895521017
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 64
    Digitale Medien
    Digitale Medien
    Identification of a novel moth sex pheromone inEriocrania cicatricella (Zett.) (Lepidoptera: Eriocraniidae) and its phylogenetic implications (1995)
    Springer
    Journal of chemical ecology 21 (1995), S. 29-43 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Eriocrania cicatricella ; Eriocrania sparrmannella ; Eriocraniidae ; Lepidoptera ; sex pheromone ; EAG ; GC-EAD ; mass spectrometry ; synthesis ; evolution ; (Z)-4-hepten-2-one ; (2R)-heptan-2-ol ; (2R)-(Z)-4-hepten-2-ol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Extracts from different body parts of adult femaleEriocrania cicatricella (Zett.) were tested for electrophysiological activity on conspecific male antennae. Extracts from the Vth abdominal segment, containing a pair of exocrine glands, elicited the largest electroantennographic response when compared to extracts of other body parts. Female extracts were analyzed by gas chromatography with simultaneous flame ionization and electroantennographic detection (EAD). The EAD active peaks were identified as (Z)-4-hepten-2-one, (2R)-heptane-2-ol, and (2R)-(Z)-4-hepten-2-ol by coinjection on a gas chromatography and by comparison of mass spectra with those of synthetic standards. In field tests, a blend of these three pheromone components was highly attractive to conspecific males, and a subtractive assay confirmed that the unsaturated alcohol is the major pheromone component, whereas no definite behavioral activity could be assigned to the ketone or the saturated alcohol. A bait containing the two alcohols withS-configuration was attractive to maleE. sparrmannella (Bosc), whereas no males ofE. cicatricella were found in these traps. The sex pheromone compounds inE. cicatricella are chemically similar to pheromones reported in Trichoptera and they are produced in homologous glands.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02033660
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 65
    Digitale Medien
    Digitale Medien
    Olefinic acetates, Δ-9,11–14: OAc and Δ-7,9–12: OAc used as sex pheromone components in three geometrid moths,Idaea aversata, I. straminata, andI. biselata (Geometridae, Lepidoptera) (1996)
    Springer
    Journal of chemical ecology 22 (1996), S. 1505-1526 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Sex pheromone ; Idaea aversata ; Idaea straminata ; Idaea biselata ; (Z,Z)-9,11-tetradecadienyl acetate ; (Z,Z)-7,9-dodecadienyl acetate ; (Z,E)-7,9-dodecadienyl acetate ; Lepidoptera ; Geometridae ; electroantennography ; single cell recording ; biosynthesis ; phylogeny ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Pheromone compounds so far identified from most geometrid moths consist of all-Z diene, triene, or tetraene hydrocarbons with chain lengths of C17 to C21, and their monoepoxide derivatives biosynthesized from linoleic and linolenic acids. The present study reports the occurrence of olefinic acetates as sex pheromones in three species of Geometridae. (Z,Z)-9,11-tetradecadienyl acetate and (Z,Z)-7,9-dodecadienyl acetate found in female gland extracts ofIdaea aversata elicited significant responses from conspecific male antennae in gas chromatography with electroantennographic detection (GCEAD). In extracts ofI. straminata, (Z,Z)-7,9-dodecadienyl acetate, (E,Z)-7,9-dodecadienyl acetate, and (Z,Z)-7,9-dodecadienyl acetate were found, and the synthetic compounds elicited strong responses from conspecific male antennae. In the third species,I. biselata, only (Z,Z)-7,9-dodecadienyl acetate was found in the female extracts, and this compound elicited a strong EAD response from the conspecific male antenna. The identities of the pheromone components inI. aversata andI. straminata were further confirmed according to their characteristic ions after GC-MS analyses. Single sensillum recordings fromI. aversata showed two types of pheromone-detecting sensilla present on the male antenna. One type contained two receptor neurons, one of which was specifically tuned to (Z,Z)-9,11-tetradecadienyl acetate, the other to (Z,E)-9,11-tetradecadienyl acetate. A second type contained one neuron responding to (Z,Z)-7,9-dodecadienyl acetate. The two types were clearly different also with respect to external morphology, the former being considerably longer and having a larger base diameter. Also inI. straminata two physiological types of sensilla could be distinguished. One type contained two neurons, one of which responded to (Z,Z)-7,9-dodecadienyl acetate, the other to (Z,E)-9,11-tetradecadienyl acetate. The second type contained one neuron, responding to (Z,Z)-7,9-dodecadienyl acetate. No correlation between external morphology and physiological response of the investigated sensilla was observed inI. straminata. In field tests, a two-component blend containing (Z,Z)-9,11-tetradecadienyl acetate and (Z,Z)-7,9-dodecadienyl acetate in a ratio of 10:1 was attractive to males ofI. aversata. This two-component blend was also attractive to males ofI. straminata, but in a ratio of 1:1. High numbers of maleI. biselata were caught in traps baited with (Z,Z)-7,9-dodecadienyl acetate alone. The incorporation of deuterium labels into pheromone components after topical application of deuterium-labeled palmitic acid confirmed that the pheromone components ofI. aversata could be synthesized from this precursor, as has been previously observed for acetate pheromone components of many other moth species. Our results suggest that an evolutionary reversal back to the production of palmitic acid-derived pheromone components has occurred within the geometrid subfamily Sterrhinae.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02027728
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 66
    Digitale Medien
    Digitale Medien
    Multiple Functions for Secondary Metabolites in Encrusting Marine Invertebrates (1997)
    Springer
    Journal of chemical ecology 23 (1997), S. 1527-1547 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Secondary metabolites ; chemical defense ; evolution ; ascidians ; sponges
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract We used three chemical fractions (spanning a wide range of polarities) from the extracts of four marine invertebrates, the spongesCrambe crambe andHemimycale columella and the ascidiansCystodytes dellechiajei andPolysyncraton lacazei, to test inhibition of cell division, photosynthesis, and settlement. We used assay organisms from the same habitat, seeking to determine whether a species may display diverse, ecologically relevant bioac-tivities and, if so, whether the same types of compound may be responsible for such activities. Cell division was strongly inhibited by the spongeC. crambe. A dichloromethane fraction fromC. crambe prevented development of sea urchinParacentrotus lividus eggs at a concentration of 10 μg/ml, as did the butanolic fraction, but at higher concentrations (50 and 100 μg/ml). At 50 μg/ml, the aqueous fraction ofC. crambe allowed cell division but prevented eggs from developing beyond the gastrula stage. Similar results were recorded with the dichloromethane fraction ofP. lacazei and from the aqueous fraction ofH. columella. Photosynthesis was unaffected by any of the species at 50 μg/ml. Larval settlement was inhibited by one or another fraction from the four species surveyed at a concentration of 50 μg/ml, althoughC. crambe exhibited the greatest amount of activity. We therefore found that various fractions displayed the same type of bioactivity, while compounds from the same fraction were responsible for multiple activities, suggesting that secondary metabolites are multiple-purpose tools in nature, which is relevant to our understanding of species ecology and evolution. Moreover, results showed that the assessment of the role of chemical compounds is significantly influenced by the assay organism, fractionation procedure, concentration, and duration of experiments. All these factors should be carefully considered when testing ecological hypotheses of the roles of chemically-mediated bioactivities.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/B:JOEC.0000006420.04002.2e
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 67
    Digitale Medien
    Digitale Medien
    From Chemical to Population Ecology: Infochemical Use in an Evolutionary Context (1999)
    Springer
    Journal of chemical ecology 25 (1999), S. 31-49 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Chemical ecology ; evolution ; variation ; population dynamics ; community ; species interactions ; infochemical ; semiochemical ; parasitoid ; foraging behavior ; learning ; phenotypic plasticity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The marriage of chemistry with ecology has been a productive one, providing a wealth of examples of how chemicals play important roles in the loves and lives of living organisms. At first the marriage may have been a simple and monogamous one with the major scientific aim of making proximate analyses of chemically mediated, individual level interactions. But times have changed and chemical ecology is broadening, embracing different approaches and disciplines. There is, for example, increasing appreciation of variability in the systems under study and an increase in evolutionary thinking. Another promising development is greater recognition of the potential importance of chemically mediated interactions for population dynamics and for structuring communities and species coexistence. The latter is an utterly underexplored area in chemical ecology. The field of chemical ecology of insect parasitoids shows some of these promising developments. Responses of parasitoids to infochemicals are increasingly studied with an integrated approach of mechanism and function. This integration of “how” and “why” questions significantly enhances the evolutionary and ecological understanding of stimulus–response patterns. The future challenge in chemical ecology is to demonstrate how chemically mediated interactions steer ecological and evolutionary processes at all levels of ecological organization. To reach this goal there is a need for interdisciplinary collaboration among chemists and ecologists working at different levels of organization and with different approaches, with other disciplines as partners.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1020833015559
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 68
    Digitale Medien
    Digitale Medien
    The accumulation of geophysical data in digitized format may give glimpses into the evolution of the Earth (2000)
    Springer
    The environmentalist 20 (2000), S. 257-271 
    Details
    ISSN: 1573-2991
    Schlagwort(e): evolution ; tides ; sea level ; time series
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Energietechnik
    Notizen: Abstract The increasing use of computers since the 1960s, has implied the digitization of observations in meteorology, oceanography and other observational sciences. Enough data has been accumulated to suggest that some patterns of evolution in the world may be discernable. The present article deals with what appears as changing tides around Canada.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006712100068
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 69
    Digitale Medien
    Digitale Medien
    Interspecies relationships among ADP-ribosylation factors (ARFs): Evidence of evolutionary pressure to maintain individual identities (1996)
    Springer
    Molecular and cellular biochemistry 159 (1996), S. 15-23 
    Details
    ISSN: 1573-4919
    Schlagwort(e): guanine nucleotide-binding proteins ; evolution ; phylogeny ; structure-function
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract ADP-ribosylation factors (ARFs) are ∼20-kDa guanine nucleotide-binding proteins that are allosteric activators of the NAD:arginine ADP-ribosyltransferase activity of cholera toxin and appear to play a role in intracellular vesicular trafficking. Although the physiological roles of these proteins have not been defined, it has been presumed that each has a specific intracellular function. To obtain genetic evidence that each ARF is under evolutionary pressure to maintain its structure, and presumably function, rat ARF cDNA clones were isolated and their nucleotide and deduced amino acid sequences were compared to those of other mammalian ARFs. Deduced amino acid sequences for rat ARFs 1, 2, 3, 5 and 6 were identical to those of the known cognate human and bovine ARFs; rat ARF4 was 96% identical to human ARF4. Nucleotide sequences of both the untranslated as well as the coding regions were highly conserved. These results indicate that the ARF proteins are, as a family, extraordinarily well conserved across mammalian species. The unusually high degree of conservation of the untranslated regions is consistent with these regions having important regulatory roles and that individual ARFs contain structurally unique elements required for specific functions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00226058
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 70
    Digitale Medien
    Digitale Medien
    Determination of the relative NH proton lifetimes of the peptide analogue viomycin in aqueous solution by NMR-based diffusion measurement (1999)
    Springer
    Journal of biomolecular NMR 13 (1999), S. 25-30 
    Details
    ISSN: 1573-5001
    Schlagwort(e): amide ; diffusion ; exchange ; viomycin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract In aqueous solution, exchanging peptide NH protons experience two environments, that of the peptide itself with a relatively slow diffusion coefficient and that of the water solvent with a faster diffusion coefficient. Although in slow exchange on the NMR chemical shift timescale, the magnetic field gradient dependence of the NH peak intensities in an experiment used to measure diffusion coefficients reflects the relative time periods spent in the two environments and this allows the determination of the relative solvent accessibility of exchangeable protons in peptides or proteins. To test this approach, the magnetic field gradient dependent intensities of the chemically shifted amide and amine NH protons of the peptide antibiotic viomycin have been measured using the high resolution longitudinal-eddy-current-delay (LED) NMR method incorporating solvent water peak elimination by non-excitation. The NH resonances of viomycin have been assigned previously and their relative exchange rates determined. Here, the gradient dependence of each NH proton intensity is reported, and these, after a bi- exponential least squares fitting, yield the fractional lifetimes of the protons spent in the peptide and water environments during the diffusion period of the experiment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008393202076
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 71
    Digitale Medien
    Digitale Medien
    Allozymic characterization and evolutionary relationships in the BrazilianAkodon cursor species group (Rodentia-Cricetidae) (1995)
    Springer
    Biochemical genetics 33 (1995), S. 283-295 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Akodon ; Cricetidae rodents ; genetic diversity ; biochemical polymorphism ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The present study involved an electrophoretic survey of 22 protein loci in 269 individuals belonging to three species of the genusAkodon, A. aff.cursor (2n=16),A. cursor (2n=14/15), andA. montensis (2n=24/25/26), collected in Eastern Brazil. The joint results of gene diversity, genetic distances, phenetic analyses, and phylogenetic trees suggested thatA. aff.cursor has recently separated fromA. cursor and that the three species have experienced a recent chromosomal divergence followed by low allozyme differentiation. These data are in agreement with their classification as sibling species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00553809
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 72
    Digitale Medien
    Digitale Medien
    Chemotaxis of the unicellular green algaDunaliella salina and the ciliatedTetrahymena pyriformis—effects of glycine, lysine, and alanine, and their oligopeptides (1996)
    Springer
    Bioscience reports 16 (1996), S. 467-476 
    Details
    ISSN: 1573-4935
    Schlagwort(e): Chemotaxis ; evolution ; oligopeptides ; Tetrahymena ; Dunaliella
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Chemotactic properties of amino acids (L-alanine, glycine and L-lysine) and their oligopeptides (10−6M) and binding sites to these ligands were investigated in two unicellular models, the heterotrophicTetrahymena pyriformis and the auxotrophicDunaliella salina. Chemotaxis ofDunaliella induced by simple amino acids and their derivatives demonstrated that binding sites (receptors) for food molecules are not only present in the membrane but are also able to induce their basic physiological response. InTetrahymena, substances with special molecular structure and properties (polar, hydrophilic character of the signal peptide chain)-5-L-Lys, 5-Glywere required for chemoattraction, other peptides tested, lacking the required structure, were repellent. Divergences in chemotaxis and binding assays of both species suggest that trends of functional and binding parameters do not run parallel at this level of evolution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01198462
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 73
    Digitale Medien
    Digitale Medien
    Genome Organization and Phylogenetic Distribution of a Novel Family of Ancient Murine Endogenous Proviruses with Evidence for Transposition-Mediated Proliferation (2000)
    Springer
    Biochemical genetics 38 (2000), S. 253-265 
    Details
    ISSN: 1573-4927
    Schlagwort(e): ancient endogenous provirus ; evolution ; retrotransposition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A new family of murine endogenous proviruses (VL6.0) is described here. The intact provirus is near 6 kb in length and shows a genomic organization of 5" LTR, gag, pol, env, and 3" LTR. The primer binding site (PBS) is that of a tRNAgly. The lack of functional open reading frames and occurrence of significant gaps in most, if not all, members of this group show it to be ancient. Our estimate of copy number per haploid genome is 30+. Members of this group have been isolated from Mus musculus domesticus, M. m. casteneus, M. m. hortulanus, M. caroli, and M. spretus. The occurrence of these sequences throughout such diverse members of the genus Mus may indicate that the date of the original infection predated the divergence of the extant Mus lineages at around 2.5 million years ago. Analysis of gap (deletion/insertion) patterns indicates that these sequences may have proliferated within the Mus genome by a mechanism of reverse transcriptase-mediated transposition. As yet, there are no closely related murine retroviruses described. The closest mammalian retrovirus based on sequence similarity is from the miniature swine (Sus scrofa).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1002075821782
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 74
    Digitale Medien
    Digitale Medien
    Molecular cloning, characterization and expression analysis of two catalase isozyme genes in barley (1995)
    Springer
    Plant molecular biology 29 (1995), S. 1005-1014 
    Details
    ISSN: 1573-5028
    Schlagwort(e): evolution ; genome mapping ; isozymes ; oxygen radicals ; powdery mildew
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Clones representing two distinct barley catalase genes, Cat1 and Cat2, were found in a cDNA library prepared from seedling polysomal mRNA. Both clones were sequenced, and their deduced amino acid sequences were found to have high homology with maize and rice catalase genes. Cat1 had a 91% deduced amino acid sequence identity to CAT-1 of maize and 92% to CAT B of rice. Cat2 had 72 and 79% amino acid sequence identities to maize CAT-2 and-3 and 89% to CAT A of rice. Barley, maize or rice isozymes could be divided into two distinct groups by amino acid homologies, with one group homologous to the mitochondria-associated CAT-3 of maize and the other homologous to the maize peroxisomal/glyoxysomal CAT-1. Both barley CATs contained possible peroxisomal targeting signals, but neither had favorable mitochondrial targeting sequences. Cat1 mRNA occurred in whole endosperms (aleurones plus starchy endosperm), in isolated aleurones and in developing seeds, but Cat2 mRNA was virtually absent. Both mRNAs displayed different developmental expression patterns in scutella of germinating seeds. Cat2 mRNA predominated in etiolated seedling shoots and leaf blades. Barley genomic DNA contained two genes for Cat1 and one gene for Cat2. The Cat2 gene was mapped to the long arm of chromosome 4, 2.9 cM in telomeric orientation from the mlo locus conferring resistance to the powdery mildew fungus (Erysiphe graminis f.sp. hordei).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00014973
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 75
    Digitale Medien
    Digitale Medien
    Isolation, expression, and evolution of the gene encoding mitochondrial elongation factor Tu in Arabidopsis thaliana (1995)
    Springer
    Plant molecular biology 29 (1995), S. 1057-1070 
    Details
    ISSN: 1573-5028
    Schlagwort(e): Arabidopsis ; EF-Tu ; evolution ; gene families ; mitochondria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have characterized a second nuclear gene (tufM) in Arabidopsis thaliana that encodes a eubacterial-like protein synthesis elongation factor Tu (EF-Tu). This gene does not closely resemble the previously described Arabidopsis nuclear tufA gene, which encodes the plastid EF-Tu, and does not contain sequence elements found in all cyanobacterial and plastid tufA genes. However, the predicted amino acid sequence includes an N-terminal extension which resembles an organellar targeting sequence and shares three unique sequence elements with mitochondrial EF-Tu's, from Saccharomyces cerevisiae and Homo sapiens, suggesting that this gene encodes the Arabidopsis mitochondrial EF-Tu. Consistent with this interpretation, the gene is expressed at a higher level in flowers than in leaves. Phylogenetic analysis confirms the mitochondrial character of the sequence and indicates that the human, yeast, and Arabidopsis tufM genes have undergone considerably more sequence divergence than their cytoplasmic counterparts, perhaps reflecting a cross-compartmental acceleration of gene evolution for components of the mitochondrial translation apparatus. As previously observed for tufA, the tufM gene is present in one copy in Arabidopsis but in several copies in other species of crucifers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00014977
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 76
    Digitale Medien
    Digitale Medien
    Cloning of the amphibolic Calvin cycle/OPPP enzyme d-ribulose-5-phosphate 3-epimerase (EC 5.1.3.1) from spinach chloroplasts: functional and evolutionary aspects (1995)
    Springer
    Plant molecular biology 29 (1995), S. 1279-1291 
    Details
    ISSN: 1573-5028
    Schlagwort(e): carbon fixation ; oxidative pentose phosphate pathway ; chloroplasts ; evolution ; endosymbiosis ; isoenzymes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Exploiting the differential expression of genes for Calvin cycle enzymes in bundle-sheath and mesophyll cells of the C4 plant Sorghum bicolor L., we isolated via subtractive hybridization a molecular probe for the Calvin cycle enzyme d-ribulose-5-phosphate 3-epimerase (R5P3E) (EC 5.1.3.1), with the help of which several full-size cDNAs were isolated from spinach. Functional identity of the encoded mature subunit was shown by R5P3E activity found in affinity-purified glutatione S-transferase fusions expressed in Escherichia coli and by three-fold increase of R5P3E activity upon induction of E. coli overexpressing the spinach subunit under the control of the bacteriophage T7 promoter, demonstrating that we have cloned the first functional ribulose-5-phosphate 3-epimerase from any eukaryotic source. The chloroplast enzyme from spinach shares about 50% amino acid identity with its homologues from the Calvin cycle operons of the autotrophic purple bacteria Alcaligenes eutrophus and Rhodospirillum rubrum. A R5P3E-related eubacterial gene family was identified which arose through ancient duplications in prokaryotic chromosomes, three R5P3E-related genes of yet unknown function have persisted to the present within the E. coli genome. A gene phylogeny reveals that spinach R5P3E is more similar to eubacterial homologues than to the yeast sequence, suggesting a eubacterial origin for this plant nuclear gene.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00020468
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 77
    Digitale Medien
    Digitale Medien
    Molecular characterization of transketolase (EC 2.2.1.1) active in the Calvin cycle of spinach chloroplasts (1996)
    Springer
    Plant molecular biology 32 (1996), S. 475-484 
    Details
    ISSN: 1573-5028
    Schlagwort(e): carbon fixation ; chloroplasts ; evolution ; isoenzymes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A cDNA encoding the Calvin cycle enzyme transketolase (TKL; EC 2.2.1.1) was isolated from Sorghum bicolor via subtractive differential hybridization, and used to isolate several full-length cDNA clones for this enzyme from spinach. Functional identity of the encoded mature subunit was shown by an 8.6-fold increase of TKL activity upon induction of Escherichia coli cells that overexpress the spinach TKL subunit under the control of the bacteriophage T7 promoter. Chloroplast localization of the cloned enzyme is shown by processing of the in vitro synthesized precursor upon uptake by isolated chloroplasts. Southern blot-analysis suggests that TKL is encoded by a single gene in the spinach genome. TKL proteins of both higher-plant chloroplasts and the cytosol of non-photosynthetic eukaryotes are found to be unexpectedly similar to eubacterial homologues, suggesting a possible eubacterial origin of these nuclear genes. Chloroplast TKL is the last of the demonstrably chloroplast-localized Calvin cycle enzymes to have been cloned and thus completes the isolation of gene probes for all enzymes of the pathway in higher plants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00019099
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 78
    Digitale Medien
    Digitale Medien
    Phylogenetic relationship among all living species of the genusBubalus based on DNA sequences of the cytochromeb gene (1996)
    Springer
    Biochemical genetics 34 (1996), S. 443-452 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Bubalus ; tamaraw ; anoa ; cytochromeb ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The cytochromeb genes of all living species ofBubalus, including the river type and the swamp type of domestic buffaloes (Bubalus bubalis), were sequenced to clarify their phylogenetic relationships. These sequences were compared together with the African buffalo (Syncerus caffer) and banteng (Bos javanicus) sequences as an outgroup. Phylogenetic trees ofBubalus species based on the DNA sequences of the cytochromeb gene demonstrated that the tamaraw (Bubalus mindorensis), endemic to the Philippines, could be classified into the subgenusBubalus, not the subgenusAnoa. The divergence time between the lowland anoa (B. depressicornis) and the mountain anoa (B. quarlesi) was estimated at approximately 2.0 million years (Myr), which is almost the same as the coalescence time for theBubalus sequences. This large genetic distance supports the idea that the lowland anoa and the mountain anoa are different species. An unexpectedly large genetic distance between the river and the swamp type of domestic buffaloes suggests a divergence time of about 1.7 Myr, while the swamp type was noticed to have the closest relationship with the tamaraw (1.5 Myr). This result implies that the two types of domestic buffaloes have differentiated at the full species level.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00570125
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 79
    Digitale Medien
    Digitale Medien
    Ribonuclease P from plant nuclei and photosynthetic organelles (1995)
    Springer
    Molecular biology reports 22 (1995), S. 139-145 
    Details
    ISSN: 1573-4978
    Schlagwort(e): chloroplast ; cyanelle ; evolution ; pre-tRNA processing ; ribozyme ; wheat germ
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract RNase P consists of both protein and RNA subunits in all organisms and organelles investigated so far, with the exception of chloroplasts and plant nuclei where no enzyme-associated RNA has been detected to date. Studies on substrate specificity revealed that cleavage by plant nuclear RNase P is critically dependent on a complete and intact structure of the substrate. No clearcut answer is yet possible regarding the order of processing events at the 5′ or 3′ end of tRNAs in the case of nuclear or chloroplast processing enzymes. RNase P from a phylogenetically ancient photosynthetic organelle will be discussed in greater detail: The enzyme from theCyanophora paradoxa cyanelle is the first RNase P from a photosynthetic organelle which has been shown to contain an essential RNA subunit. This RNA is strikingly similar to its counterpart from cyanobacteria, yet it lacks catalytic activity. Properties of the holoenzyme suggest an intermediate position in RNA enzyme evolution, with an eukaryotic-type, inactive RNA and a prokaryotic-type small protein subunit. The possible presence of an RNA component in RNase P from plant nuclei and modern chloroplasts will be discussed, including a critical evaluation of some criteria that have been frequently applied to elucidate the subunit composition of RNase P from different organisms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00988719
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 80
    Digitale Medien
    Digitale Medien
    Protein-ligand interactions measured by 15N-filtered diffusion experiments (1999)
    Springer
    Journal of biomolecular NMR 13 (1999), S. 223-232 
    Details
    ISSN: 1573-5001
    Schlagwort(e): diffusion ; heteronuclear filtration ; peptide binding ; protein ; SH3
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract NMR diffusion coefficient measurements have been shown to be sensitive to the conformational and oligomeric states of proteins. Recently, heteronuclear-filtered diffusion experiments have been proposed [Dingley et al. (1997) J. Biomol. NMR, 10, 1–8]. Several new heteronuclear-filtered diffusion pulse sequences are proposed which are shown to have superior sensitivity to those previously proposed. One of these new heteronuclear-filtered diffusion experiments has been used to study the binding of an SH3 domain to a peptide. Using this system, we show that it is possible to measure binding constants from diffusion coefficient measurements.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008301324954
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 81
    Digitale Medien
    Digitale Medien
    Evolution of the Group 1 late embryogenesis abundant (Lea) genes: analysis of the Lea B19 gene family in barley (1995)
    Springer
    Plant molecular biology 28 (1995), S. 1039-1054 
    Details
    ISSN: 1573-5028
    Schlagwort(e): ABA-inducible genes ; coding region repeats ; embryo-specific gene family ; evolution ; Hordeum vulgare L. ; phylogenetic analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The highly conserved Group 1 late embryogenesis abundant (Lea) genes are present in the genome of most plants as a gene family. Family members are conserved along the entire coding region, especially within the extremely hydrophilic internal 20 amino acid motif, which may be repeated. Cloning of Lea Group 1 genes from barley resulted in the characterization of four family members named B19.1, B19.1b, B19.3 and B19.4 after the presence of this motif 1, 1, 3 and 4 times in each gene, respectively. We present here the results of comparative and evolutionary analyses of the barley Group 1 Lea gene family (B19). The most important findings resulting from this work are (1) the tandem clustering of B19.3 and B19.4, (2) the spatial conservation of putative regulatory elements between the four B19 gene promoters, (3) the determination of the relative ‘age’ of the gene family members and (4) the ‘chimeric’ nature of B19.3 and B19.4, reflecting a cross-over or gene-conversion event in their common ancestor. We also show evidence for the presence of one or two additional expressed B19 genes in the barley genome. Based on our results, we present a model for the evolution of the family in barley, including the 20 amino acid motif. Comparisons of the relatedness between the barley family and all other known Group 1 Lea genes using maximum parsimony (PAUP) analysis provide evidence for the time of divergence between the barley genes containing the internal motif as a single copy and as a repeat. The PAUP analyses also provide evidence for independent duplications of Group 1 genes containing the internal motif as a repeat in both monocots and dicots.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00032665
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 82
    Digitale Medien
    Digitale Medien
    Characterization of a maize ribosomal P2 protein cDNA and phylogenetic analysis of the P1/P2 family of ribosomal proteins (1996)
    Springer
    Plant molecular biology 30 (1996), S. 655-658 
    Details
    ISSN: 1573-5028
    Schlagwort(e): cDNA ; evolution ; p2 protein ; ribosome ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The nucleotide sequence of a full-length ribosomal P2 protein cDNA from maize was determined and used for a sequence comparison with the P2 and P1 proteins from other organisms. The integration of these data into a phylogenetic tree shows that the P proteins separated into the subspecies P1 and P2 before the eukaryotic kingdoms including plants developed from their ancestor.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00049340
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 83
    Digitale Medien
    Digitale Medien
    RNA editing in plant mitochondria and chloroplasts (1996)
    Springer
    Plant molecular biology 32 (1996), S. 343-365 
    Details
    ISSN: 1573-5028
    Schlagwort(e): RNA editing ; tRNA editing ; chloroplast ; mitochondrion ; post-transcriptional modification ; initiation codon ; stop codon ; deamination ; evolution ; guide RNA ; transgenic plants ; plastid transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In the mitochondria and chloroplasts of higher plants there is an RNA editing activity responsible for specific C-to-U conversions and for a few U-to-C conversions leading to RNA sequences different from the corresponding DNA sequences. RNA editing is a post-transcriptional process which essentially affects the transcripts of protein coding genes, but has also been found to modify non-coding transcribed regions, structural RNAs and intron sequences. RNA editing is essential for correct gene expression: proteins translated from edited transcripts are different from the ones deduced from the genes sequences and usually present higher similarity to the corresponding non-plant homologues. Initiation and stop codons can also be created by RNA editing. RNA editing has also been shown to be required for the stabilization of the secondary structure of introns and tRNAs. The biochemistry of RNA editing in plant organelles is still largely unknown. In mitochondria, recent experiments indicate that RNA editing may be a deamination process. A plastid transformation technique showed to be a powerful tool for the study of RNA editing. The biochemistry as well as the evolutionary features of RNA editing in both organelles are compared in order to identify common as well as organelle-specific components.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00039390
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 84
    Digitale Medien
    Digitale Medien
    Higher-plant chloroplast and cytosolic fructose-1,6-bisphophosphatase isoenzymes: origins via duplication rather than prokaryote-eukaryote divergence (1996)
    Springer
    Plant molecular biology 32 (1996), S. 485-491 
    Details
    ISSN: 1573-5028
    Schlagwort(e): Calvin cycle ; sedoheptulose-1,7-bisphosphatase ; isoenzymes ; endosymbiosis ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Full-size cDNAs encoding the precursors of chloroplast fructose-1,6-bisphosphatase (FBP), sedoheptulose-1,7-bisphosphatase (SBP), and the small subunit of Rubisco (RbcS) from spinach were cloned. These cDNAs complete the set of homologous probes for all nuclear-encoded enzymes of the Calvin cycle from spinach (Spinacia oleracea L.). FBP enzymes not only of higher plants but also of non-photosynthetic eukaryotes are found to be unexpectedly similar to eubacterial homologues, suggesting a eubacterial origin of these eukaryotic nuclear genes. Chloroplast and cytosolic FBP isoenzymes of higher plants arose through a gene duplication event which occurred early in eukaryotic evolution. Both FBP and SBP of higher plant chloroplasts have acquired substrate specificity, i.e. have undergone functional specialization since their divergence from bifunctional FBP/SBP enzymes of free-living eubacteria.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00019100
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 85
    Digitale Medien
    Digitale Medien
    A model for the evolution of the plastid sec apparatus inferred from secY gene phylogeny (1996)
    Springer
    Plant molecular biology 32 (1996), S. 685-692 
    Details
    ISSN: 1573-5028
    Schlagwort(e): evolution ; protein transport ; sec apparatus ; secA ; secY ; thylakoid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Plastids possess a bacteria-like sec apparatus that is involved in protein import into the thylakoid lumen. We have analyzed one of the genes essential for this process, secY. A secY gene from the unicellular red alga Cyanidium caldarium was found to be transcriptionally active, demonstrating for the first time that secY is functional in a plastid. Unlike the situation seen in bacteria the C. caldarium gene is transcribed monocistronically, despite the fact that it is part of a large ribosomal gene cluster that resembles bacterial spc operons. A molecular phylogeny is presented for 8 plastid-encoded secY genes, four of which have not been published yet. In this analysis plastid secY genes fall into two classes. One of these, comprising of genes from multicellular red algae and Cryptophyta, clusters in a neighbour-joining tree with a cyanobacterial counterpart. Separated from the aforesaid are secY genes from Chromophyta, Glaucocystophyta and a unicellular red alga. All plastid and cyanobacterial sequences are located on the same branch, separated from bacterial homologues. We postulate that the two classes of secY genes are paralogous, i.e. their gene products are involved in different protein translocation processes. Based on this assumption a model for the evolution of the plastid sec apparatus is presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00020209
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 86
    Digitale Medien
    Digitale Medien
    Evolutionary origin of expandable G-C-rich triplet repeat DNA sequences (1995)
    Springer
    Biochemical genetics 33 (1995), S. 173-181 
    Details
    ISSN: 1573-4927
    Schlagwort(e): fragile-X DNA systems ; expandable triplet repeats ; dynamic mutations ; conserved genetic domains ; evolution ; heritable disease mechanism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A model explaining properties exhibited by fragile-X DNA systems arises from observations that time-dependent base substitutions are expressed at G-C sites but not at A–T sites (Biochem. Genet.32:383, 1994). [CGG]n sequences are classified as most sensitive to evolutionary base substitution processes involving time-dependent populating of G-C sites with enol-imine states having enhanced stability. Increased density of these states in oocyte DNA would introduce a ground-state collapse double-helix of reduced energy that would inhibit strand separation by the replicase. Evolutionarily altered G′ in CG′G triplets allows CG′G to be transcribed as CTG, an initiation codon. And this will cause reinitiation of DNA synthesis, thereby adding additional CGG units to the collapsed double helix. This situation would not occur in slower-evolving male haploid DNA that replicates frequently.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00554729
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 87
    Digitale Medien
    Digitale Medien
    Allozymic characterization and evolutionary relationships in the BrazilianAkodon cursor species group (Rodentia-Cricetidae) (1995)
    Springer
    Biochemical genetics 33 (1995), S. 283-295 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Akodon ; Cricetidae rodents ; genetic diversity ; biochemical polymorphism ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The present study involved an electrophoretic survey of 22 protein loci in 269 individuals belonging to three species of the genusAkodon, A. aff.cursor (2n=16),A. cursor (2n=14/15), andA. montensis (2n=24/25/26), collected in Eastern Brazil. The joint results of gene diversity, genetic distances, phenetic analyses, and phylogenetic trees suggested thatA. aff.cursor has recently separated fromA. cursor and that the three species have experienced a recent chromosomal divergence followed by low allozyme differentiation. These data are in agreement with their classification as sibling species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02399928
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 88
    Digitale Medien
    Digitale Medien
    Gene-specific universal mammalian sequence-tagged sites: Application to the canine genome (1996)
    Springer
    Biochemical genetics 34 (1996), S. 321-341 
    Details
    ISSN: 1573-4927
    Schlagwort(e): genome mapping ; evolution ; homology ; polymerase chain reaction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract We are developing a genetic map of the dog based partly upon markers contained within known genes. In order to facilitate the development of these markers, we have used polymerase chain reaction (PCR) primers designed to conserved regions of genes that have been sequenced in at least two species. We have refined the method for designing primers to maximize the number that produce successful amplifications across as many mammalian species as possible. We report the development of primer sets for 11 loci in detail:CFTR, COL10A1, CSFIR, CYP1A1, DCN1, FES, GHR, GLB1, PKLR, PVALB, andRB1. We also report an additional 75 primer sets in the appendices. The PCR products were sequenced to show that the primers amplify the expected canine genes. These primer sets thus define a class of gene-specific sequence-tagged sites (STSs). There are a number of uses for these STSs, including the rapid development of various linkage tools and the rapid testing of genomic and cDNA libraries for the presence of their corresponding genes. Six of the eleven gene targets reported in detail have been proposed to serve as “anchored reference loci” for the development of mammalian genetic maps [O'Brien, S. J.,et al., Nat. Genet. 3:103, 1993]. The primer sets should cover a significant portion of the canine genome for the development of a linkage map. In order to determine how useful these primer sets would be for the other genome projects, we tested the 11 primer sets on the DNA from species representing five mammalian orders. Eighty-four percent of the gene-species combinations amplified successfully. We have named these primer sets “universal mammalian sequence-tagged sites” because they should be useful for many mammalian genome projects.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00553904
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 89
    Digitale Medien
    Digitale Medien
    Gene-specific universal mammalian sequence-tagged sites: Application to the canine genome (1996)
    Springer
    Biochemical genetics 34 (1996), S. 321-341 
    Details
    ISSN: 1573-4927
    Schlagwort(e): genome mapping ; evolution ; homology ; polymerase chain reaction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract We are developing a genetic map of the dog based partly upon markers contained within known genes. In order to facilitate the development of these markers, we have used polymerase chain reaction (PCR) primers designed to conserved regions of genes that have been sequenced in at least two species. We have refined the method for designing primers to maximize the number that produce successful amplifications across as many mammalian species as possible. We report the development of primer sets for 11 loci in detail:CFTR, COL10A1, CSFIR, CYP1A1, DCN1, FES, GHR, GLB1, PKLR, PVALB, andRB1. We also report an additional 75 primer sets in the appendices. The PCR products were sequenced to show that the primers amplify the expected canine genes. These primer sets thus define a class of gene-specific sequence-tagged sites (STSs). There are a number of uses for these STSs, including the rapid development of various linkage tools and the rapid testing of genomic and cDNA libraries for the presence of their corresponding genes. Six of the eleven gene targets reported in detail have been proposed to serve as “anchored reference loci” for the development of mammalian genetic maps [O'Brien, S. J.,et al., Nat. Genet. 3:103, 1993]. The primer sets should cover a significant portion of the canine genome for the development of a linkage map. In order to determine how useful these primer sets would be for the other genome projects, we tested the 11 primer sets on the DNA from species representing five mammalian orders. Eighty-four percent of the gene-species combinations amplified successfully. We have named these primer sets “universal mammalian sequence-tagged sites” because they should be useful for many mammalian genome projects.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02399951
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 90
    Digitale Medien
    Digitale Medien
    The primary structure ofHarpalus rufipes 5S ribosomal RNA (1995)
    Springer
    Molecular biology reports 21 (1995), S. 165-167 
    Details
    ISSN: 1573-4978
    Schlagwort(e): 5S ribosomal RNA ; Harpalus rufipes ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The nucleotide sequence of 5S ribosomal RNA from the beetleHarpalus rufipes was determined and compared with primary structures of other insect 5S rRNAs. Sequence differences between two beetle 5S rRNAs may represent phylogenetic markers specific for two groups of Coleoptera — Adephaga and Polyphaga. Analysis of all insect sequences using parsimony allowed us to infer a phylogenetic tree of insects, which is consistent with morphological and paleobiological data.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00997239
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 91
    Digitale Medien
    Digitale Medien
    The myrosinase gene family in Arabidopsis thaliana: gene organization, expression and evolution (1995)
    Springer
    Plant molecular biology 27 (1995), S. 911-922 
    Details
    ISSN: 1573-5028
    Schlagwort(e): Arabidopsis ; evolution ; expression ; genomic clone ; in situ hybridization ; myrosinase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Myrosinase (thioglucoside glucohydrolase, EC 3.2.3.1.) is in Brassicaceae species such as Brassica napus and Sinapis alba encoded by two differentially expressed gene families, MA and MB, consisting of about 4 and 10 genes, respectively. Southern blot analysis showed that Arabidopsis thaliana contains three myrosinase genes. These genes were isolated from a genomic library and two of them, TGG1 and TGG2, were sequenced. They were found to be located in an inverted mode with their 3′ ends 4.4 kb apart. Their organization was highly conserved with 12 exons and 11 short introns. Comparison of nucleotide sequences of TGG1 and TGG2 exons revealed an overall 75% similarity. In contrast, the overall nucleotide sequence similarity in introns was only 42%. In intron 1 the unusual 5′ splice border GC was used. Phylogenetic analyses using both distance matrix and parsimony programs suggested that the Arabidopsis genes could not be grouped with either MA or MB genes. Consequently, these two gene families arose only after Arabidopsis had diverged from the other Brassicaceae species. In situ hybridization experiments showed that TGG1 and TGG2 expressing cells are present in leaf, sepal, petal, and gynoecium. In developing seeds, a few cells reacting with the TGG1 probe, but not with the TGG2 probe, were found indicating a partly different expression of these genes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00037019
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 92
    Digitale Medien
    Digitale Medien
    Two copies of a DNA element, ‘Wendy’, in the chloroplast chromosome of Chlamydomonas reinhardtii between rearranged gene clusters (1995)
    Springer
    Plant molecular biology 29 (1995), S. 63-80 
    Details
    ISSN: 1573-5028
    Schlagwort(e): evolution ; Chlamydomonas reinhardtii ; chloroplast ; site-specific recombination ; transcription ; transposition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have characterized two copies of a 2.4 kb DNA element that we call ‘Wendy’, in the chloroplast chromosome of Chlamydomonas reinhardtii. The two copies of Wendy reside in different single-copy regions at opposite positions in the chloroplast genome. Like many mobile DNA elements, both copies of Wendy are bordered by inverted repeats and contain several additional degenerate copies of these repeat sequences in direct or inverted orientation. In addition, four basepairs are repeated in direct orientation. Two major open reading frames (ORFs) are predicted from the DNA sequence of Wendy I. These ORFs are co-transcribed from a promoter inside the element. The deduced amino acid sequence of the larger of these ORFs shares some weak similarities with sequence motifs of transposases and integrases of other mobile elements. Wendy II appears to be altered relative to Wendy I by point mutations and small deletions and insertions which destroy the ORFs. The leader sequence of the Wendy transcript is nearly identical with the leader sequence of the rbcL transcript of C. reinhardtii, but not of C. moewusii (where the complete Wendy was also undetectable). Furthermore, both copies of Wendy are bracketed by gene clusters that are separated in C. reinhardtii but are contiguous in C. moewusii where they exist in an inverted orientation compared with C. reinhardtii. Wendy was not found in any of the completely sequenced chloroplast genomes of rice, tobacco, pine, Euglena or Marchantia, nor in any other GenBank entry. Our results suggest that Wendy has invaded C. reinhardtii after divergence from other species. Subsequent Wendy-dependent illegitimate homologous or site-specific recombination events or both may have contributed to scrambling of the C. reinhardtii chloroplast genome relative to genomes of other species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00019119
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 93
    Digitale Medien
    Digitale Medien
    Elongation factor 1α genes of the red alga Porphyra purpurea include a novel, developmentally specialized variant (1996)
    Springer
    Plant molecular biology 31 (1996), S. 77-85 
    Details
    ISSN: 1573-5028
    Schlagwort(e): developmental regulation ; elongation factor ; evolution ; gene expression ; rhodophyte, sporophyte
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The life cycle of the red alga Porphyra purpurea alternates between two morphologically distinct phases: a shell-boring, filamentous sporophyte and a free-living, foliose gametophyte. From a subtracted cDNA library enriched for sporophyte-specific sequences, we isolated a cDNA encoding an unusual elongation factor 1α (EF-1α) that is expressed only in the sporophyte. A second EF-1α gene that is expressed equally in the sporophyte and the gametophyte was isolated from a genomic library. These are the only EF-1α genes detectable in P. purpurea. The constitutively expressed gene encodes and EF-1α very similar to those of most eukaryotes. However, the sporophyte-specific EF-1α is one of the most divergent yet described, with nine insertions or deletions ranging in size from 1 to 26 amino acids. This is the first report of a developmental stage-specific EF-1α outside of the animal kingdom and suggests a fundamental role for EF-1α in the developmental process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00020608
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 94
    Digitale Medien
    Digitale Medien
    Regulation, unique gene organization, and unusual primary structure of carbon fixation genes from a marine phycoerythrin-containing cyanobacterium (1996)
    Springer
    Plant molecular biology 32 (1996), S. 1103-1115 
    Details
    ISSN: 1573-5028
    Schlagwort(e): carboxysomes ; evolution ; ribulose 1,5-bisphosphate carboxylase/oxygenase ; Synechococcus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Marine phycoerythrin-containing cyanobacteria are major contributors to the overall productivity of the oceans. The present study indicates that the structural genes of the carbon assimilatory system are unusually arranged and possess a unique primary structure compared to previously studied cyanobacteria. Southern blot analyses of Synechococcus sp. strain WH7803 chromosomal DNA digests, using the ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) large subunit gene from Synechococcus sp. strain PCC6301 as a heterologous probe, revealed the presence of a 6.4 kb HindIII fragment that was detectable at only low stringency. Three complete open reading frames (ORFs) were detected within this fragment. Two of these ORFs potentially encode the Synechococcus sp. strain WH7803 rbcL and rbcS genes. The third ORF, situated immediately upstream from rbcL, potentially encodes a homologue of the ccmK gene from Synechococcus sp. strain PCC7942. The deduced amino acid sequences of each of these ORFs are more similar to homologues among the β/γ purple bacteria than to existing cyanobacterial homologues and phylogenetic analysis of the Rubisco large and small subunit sequences confirmed an unexpected relationship to sequences from among the β/γ purple bacteria. This is the first instance in which the possibility has been considered that an operon encoding three genes involved in carbon fixation may have been laterally transferred from a purple bacterium. Analysis of mRNA extracted from cells grown under diel conditions indicated that rbcL, rbcS and ccmK were regulated at the transcriptional level; specifically rubisco transcripts were highest during the midday period, decreased at later times during the light period and eventually reached a level where they were all but undetectable during the dark period. Primer extension analysis indicated that the ccmK, rbcL and rbcS genes were co-transcribed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00041394
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 95
    Digitale Medien
    Digitale Medien
    Molecular characterization of a phosphoenolpyruvate carboxylase in the gymnosperm Picea abies (Norway spruce) (1996)
    Springer
    Plant molecular biology 32 (1996), S. 923-936 
    Details
    ISSN: 1573-5028
    Schlagwort(e): PEPC ; C3 metabolism ; gene expression ; evolution ; gymnosperm ; Picea abies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Phosphoenolpyruvate carboxylase (PEPC) genes and cDNA sequences have so far been isolated from a broad range of angiosperm but not from gymnosperm species. We constructed a cDNA library from seedlings of Norway spruce (Picea abies) and identified cDNAs coding for PEPC. A full-length PEPC cDNA was sequenced. It consists of 3522 nucleotides and has an open reading frame (ORF) that encodes a polypeptide (963 amino acids) with a molecular mass of 109 551. The deduced amino acid sequence revealed a higher similarity to the C3-form PEPC of angiosperm species (86–88%) than to the CAM and C4 forms (76–84%). The putative motif (Lys/Arg-X-X-Ser) for serine kinase, which is conserved in all angiosperm PEPCs analysed so far, is also present in this gymnosperm sequence. Southern blot analysis of spruce genomic DNA under low-stringency conditions using the PEPC cDNA as a hybridization probe showed a complex hybridization pattern, indicating the presence of additional PEPC-related sequences in the genome of the spruce. In contrast, the probe hybridized to only a few bands under high-stringency conditions. Whereas this PEPC gene is highly expressed in roots of seedlings, a low-level expression can be detected in cotyledons and adult needles. A molecular phyiogeny of plant PEPC including the spruce PEPC sequence revealed that the spruce PEPC sequence is clustered with monocot and dicot C3-form PEPCs including the only dicot C4 form characterized so far.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00020489
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 96
    Digitale Medien
    Digitale Medien
    Competitive reversals inside ecological reserves: the role of external habitat degradation (1998)
    Springer
    Journal of mathematical biology 37 (1998), S. 491-533 
    Details
    ISSN: 1432-1416
    Schlagwort(e): Key words: Competition ; Edge effects ; Reaction ; diffusion ; Lotka ; Volterra ; Ecological reserves
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Mathematik
    Notizen: Abstract.  Habitat degradation is the slow – and often subtle – deterioration in habitat quality that accompanies human activities through increases in road density, pesticide use, hunting pressure, etc. Such degradation is of particular concern in fragmented habitats where economic or jurisdictional boundaries rather than ecological ones determine the level of exploitation adjoining habitat patches endure. To examine the consequences habitat degradation might have on species interactions, we posited a patch of pristine habitat surrounded by “matrix” habitat whose degradation level was variable. Using a coupled pair of diffusive Lotka–Volterra competition equations with Robin (mixed) boundary conditions, we modeled the dynamics of two competing species inhabiting the pristine patch and incorporated matrix degradation through a tunable “hostility” parameter representing species’ mortality rates in the matrix. We found that the numerical range of competition coefficients over which one species is the competitive dominant and the other inferior may grow or shrink as matrix quality deteriorates. In some cases, degradation of the exterior habitat would bring about a complete competitive reversal inside the preserve. This result, wherein a formerly inferior species supplants a formerly dominant one – even inside the “protected” remnant patch itself – has policy implications for both nature reserve design and management of human activities outside park boundaries.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002850050139
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 97
    Digitale Medien
    Digitale Medien
    The evolution of slow dispersal rates: a reaction diffusion model (1998)
    Springer
    Journal of mathematical biology 37 (1998), S. 61-83 
    Details
    ISSN: 1432-1416
    Schlagwort(e): Key words: Evolution of dispersal ; Migration modification ; Reaction ; diffusion ; Montone systems ; Perturbation of Morse decomposition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Mathematik
    Notizen: Abstract.  We consider n phenotypes of a species in a continuous but heterogeneous environment. It is assumed that the phenotypes differ only in their diffusion rates. With haploid genetics and a small rate of mutation, it is shown that the only nontrivial equilibrium is a population dominated by the slowest diffusing phenotype. We also prove that if there are only two possible phenotypes, then this equilibrium is a global attractor and conjecture that this is true in general. Numerical simulations supporting this conjecture and suggesting that this is a robust phenomenon are also discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002850050120
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 98
    Digitale Medien
    Digitale Medien
    A multigene phylogeny of theGibberella fujikuroi species complex: Detection of additional phylogenetically distinct species (2000)
    Springer
    Mycoscience 41 (2000), S. 61-78 
    Details
    ISSN: 1618-2545
    Schlagwort(e): biogeography ; calmodulin ; DNA sequence ; elongation factor EF-1α ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Phylogenetic relationships within theGibberella fujikuroi species complex were extended to newly discovered strains using nucleotide characters obtained by sequencing polymerase chain reaction (PCR) amplified DNA from 4 loci used in a previous study [nuclear large subunit 28S rDNA, nuclear ribosomal internal transcribed spacer (ITS) region, mitochondriaal small subunit (mtSSU) ribosomal DNA, and β-tubulin] together with two newly sampled protein-encoding nuclear genes, translation elongation factor EF-1α and calmodulin. Sequences from the ribosomal ITS region were analyzed separately and found to contain of two highly divergent, nonorthologous ITS2 types. Phylogenetic analysis of the individual and combined datasets identified 10 new phylogenetically distinct species distributed among the following three areas: 2 within Asia and 4 within both Africa and South America. Hypotheses of the monophyly ofFusarium subglutinans and its two formae speciales, f. sp.pini and f. sp.ananas, were strongly rejected by a likelihood analysis. Maximum parsimony results further indicate that the protein-encoding nuclear genes provide considerably more phylogenetic signal that the ribosomal genes sequenced. Relative apparent synapomorphy analysis was used to detect long-branch attraction taxa and to obtain a statistical measure of phylogenetic signal in the individual and combined datasets.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02464387
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 99
    Digitale Medien
    Digitale Medien
    Papulosa amerospora accommodated in a new family (papulosaceae, sordariomycetes, ascomycota) inferred from morphological and molecular data (2000)
    Springer
    Mycoscience 41 (2000), S. 97-103 
    Details
    ISSN: 1618-2545
    Schlagwort(e): Ascomycota ; evolution ; pyrenomycetes ; systematics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract To investigate the systematic position of the unitunicate pyremomycetePapulosa amerospora, we performed phylogenetic analyses of SSU rDNA sequences from 37 ascomycetes. Among these sequences were some new ones from taxa that might be related toPapulosa: Hyponectriaceae (Hyponectria buxi, Monographella nivalis), Phyllachorales (Phyllachora graminis), and Xylariales (Barrmaelia melanotes, Poronia punctata). Our results showed 100% bootstrap support for a clade of all unitunicate pyrenomycetes, the class Sordariomycetes. We also found strong support for recognizing the subclasses Hypocreomycetidae and Xylariomycetidae. The remaining taxa, belonging to subclass Sordariomycetidae, appeared as a polyphyletic group in one analysis, but was monophyletic when shorter SSU sequences were used.Barrmaelia melanotes, Poronia punctata, Hyponectria buxi, andMonographella nivalis are members of Xylariomycetidae, but we could not determine whetherMonographella should be included in Hyponectriaceae. The new family Papulosaceae is erected forPapulosa on molecular and morphological bases, but the exact systematic position ofPapulosa within subclass Sordariomycetidae is still uncertain, since the genus did not cluster consistently with any of the included taxa. Phyllachorales are not closely related to Diaporthales, as previously suggested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02464316
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 100
    Digitale Medien
    Digitale Medien
    The pollinium ofLoroglossum hircinum (Orchidaceae) between pollination and pollen tube emission (1995)
    Springer
    Plant systematics and evolution 196 (1995), S. 141-151 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Orchidaceae ; Loroglossum hircinum ; Compound pollen ; pollinium ; pollen tubes ; generative cell ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The structure of the massulae composing the pollinium ofLoroglossum hircinum was studied before pollination and 12 and 24 hours afterwards. The grains are grouped in tetrads closely packed in massulae. The exine is only present on the outside of the massulae. The intine consists of two layers: a compact layer surrounding the pollen grain and a looser layer surrounding the pollen grain and a looser layer surrounding the tetrad. Twelve hours after pollination, pollen volume and the space between the tetrads increase due to vacuolization. Twenty-four hours after pollination, pollen volume and tetrad spacing are higher due to vacuolization and some grains have emitted pollen tubes. Pollen growth due to vacuole formation, and the absence of common walls between adjacent tetrads lead to crumbling of the massulae. The mature pollen grain does not have apertures: the site of pollen tube emission is determined after pollination. The first grains to germinate are those in the centre of the massula. The vegetative cell nucleus is the first to enter the pollen tube; the generative cell elongates and undergoes the second haploid mitosis shortly after entering the pollen tube.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00982955
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...