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  • temperature  (76)
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  • 1
    Digitale Medien
    Digitale Medien
    The roles of temperature and food quality in affecting the performance of the alder aphid, Pterocallis alni (1990)
    Springer
    Entomologia experimentalis et applicata 57 (1990), S. 9-16 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Aphid ; alder ; food quality ; temperature ; ovariole number ; Pterocallis alni
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé P. alni DeGeer (Homopt. Callaphididae) vit sur Alnus glutinosa Gaertner pendant toute l'année. L'aulne étant un arbre fixant l'azote, cette étude a été entreprise pour examiner la croissance et la reproduction de ce puceron sur cet arbre afin d'expliquer les changements de la dynamique de sa population. 6 générations successives estivales ont été élevées dans la nature et en température constante au laboratoire. La qualité de l'aliment a été mesurée chaque semaine par une microkjeldahl analyse des concentrations foliaires en azote soluble. La qualité de l'aliment varie saisonnière, mais ne diminue que de 23%; elle semble n'avoir que peu d'effets sur le puceron, puisque la fécondité dans la nature n'est réduite que pendant une génération. Quand la température est maintenue constante, il n'y a pas de différences entre les performances des différentes générations de pucerons. Ainsi, les changements saisonniers dans la croissance et la reproduction des pucerons sont provoqués par la température et non par la qualité de l'aliment.
    Notizen: Abstract Six successive summer generations of the alder aphid (Pterocallis alni (DeGeer) (Homoptera: Callaphididae)) were reared simultaneously in the field and under controlled temperature conditions in the laboratory. The growth and reproduction of each generation were recorded. The available food quality for the aphids was measured by weekly analysis of foliar soluble nitrogen concentrations. Although there was a significant change in leaf soluble nitrogen during the season, the decline was only 23% and this did not appear to have an adverse effect on the performance of this aphid. Instead, the major environmental factor affecting the aphid is temperature. This is evidenced by the facts that when aphids were reared at constant temperatures, there were no differences in generation performance, even though food quality varied seasonally. In addition, all generations of the aphid posess the same number of ovarioles, indicating that there is no pre-programmed anticipation of a seasonal deterioration in food quality in this aphid species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00349590
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  • 2
    Digitale Medien
    Digitale Medien
    Are the oviposition traits of the South India strain of Callosobruchus maculatus maintained by natural selection? (1990)
    Springer
    Entomologia experimentalis et applicata 57 (1990), S. 143-150 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Bruchidae ; Callosobruchus maculatus ; competition ; development ; evolution ; fecundity ; growth rates ; host preferences ; life tables ; mortality ; natural selection ; net reproductive rate ; oviposition traits
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Le taux partiel de reproduction nette (R inf0 sup* ) dépend de l'espèce de la plante sur laquelle les œufs sont pondus et du nombre de larves entrant dans la graine. La survie larvaire est réduite par 1/(le nombre de larves par graine) parce qu'une seule larve se développe dans une graine. La fécondité n'est pas modifiée par la compétition subie par les larves, la mortalité larvaire a l'effet le plus important sur R inf0 sup* . Les femelles éliminent ou réduisent la compétition larvaire en dispersant leurs œufs uniformément et font si peu d'erreurs avec une hyperdispersion que l'évolution d'un comportement plus précis n'accroîtrait R inf0 sup* que de 4% au maximum. Des femelles retournant à une distribution des œufs au hasard provoqueraient une réduction de R inf0 sup* de 25% au moins. Les légumineuses généralement cultivées dans l'Inde du Sud sont des hôtes acceptables quand elles sont présentées seules. Le choix des femelles entre 2 hôtes élève R inf0 sup* de 30% ou plus par rapport à une distribution au hasard. Les préférences les plus nettes concernent des combinaisons présentant la plus grande différence de R inf0 sup* . Les femelles qui hyperdispersent leurs œufs, choisissent leurs hôtes et évitent les pertes par compétition en empêchant que les œufs ne donnent plus de descendants que ne le ferait une ponte au hasard. Les particularités de la ponte sont variables et héritables. Les lignées se sélectionnent bien, en fonction de la dispersion de leurs œufs sur les graines, de la discrimination des plantes hôtes, et de la modulation de leur taux de ponte. La sélection naturelle maintient ces particularités du comportement d'une façon sédentaire.
    Notizen: Abstract The deposition of eggs by this strain of Callosobruchus maculatus (Fab.) (Bruchidae: Coleoptera) departs from randomness in three ways; eggs are uniformly dispersed, oviposition rates drop when beans begin to carry 2 or more eggs, and there are sharp host preferences. Using random egg placement for the unspecialized condition, these traits are evaluated for their effect on a female's contributions of offspring to the next generation (R0, the net reproductive rate). The major increases in R0 result from females dispersing eggs so uniformly that larval competition is either reduced or eliminated. Females reduce their oviposition rate when the larva from an egg added to a bean is almost certain to die in competitive encounters. Host preferences and larval survival in a host are positively associated with the abundance of the host in South India. The three oviposition traits act together to give and R0 that is 25–50% than that of eggs placed at random. These traits are known to be variable and heritable, hence, the conditions necessary for natural selection are statisfied.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00343502
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  • 3
    Digitale Medien
    Digitale Medien
    Response of five insect herbivores to multiple allelochemicals under fluctuating temperatures (1998)
    Springer
    Entomologia experimentalis et applicata 88 (1998), S. 81-96 
    Details
    ISSN: 1570-7458
    Schlagwort(e): chlorogenic acid ; Heliothis virescens ; Manduca sexta ; Pseudoplusia includens ; rutin ; Spodoptera frugiperda ; temperature ; tomatine ; Trichoplusia ni
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Analysis of the combined effects of allelochemicals on insect herbivores is useful because there may be adverse additive or even synergistic effects. Analysis of the simultaneous effects of temperature and alleochemicals is also necessary because these factors may interact. We examined the effects of three allelochemicals found in tomato (chlorogenic acid, rutin and tomatine) and thermal regime (21:10 °C and 26:15 °C, representing spring and summer respectively) on five insect herbivores (a Solanaceae specialist, Manduca sexta, and the polyphagous Heliothis virescens, Pseudoplusia includens, Spodoptera frugiperda and Trichoplusia ni). There were allelochemical interactions and thermal regime-allelochemical interactions for all species, and so the patterns were complex. In some cases, paired allelochemicals or the combination of three allelochemicals showed adverse additive effects on insect performance. But that was not always the case, and there were only a few examples of synergism. Negative effects of the allelochemicals were sometimes, but not always, damped by the cooler thermal regime. Comparing the growth rates of the five species in this study with those of a previous study (a total of seven species) revealed five patterns. For two of three pairs of closely-related species, the paired species had distinctly different patterns. For example, for H. virescens, tomatine prevented development and chlorogenic acid slowed growth, whereas for Helicoverpa zea, tomatine just slowed growth and the phenolics had little effect. The specialist Manduca sexta had a pattern that was midway between patterns of the generalists; it was not the most tolerant of the allelochemicals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003290510565
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  • 4
    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
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  • 5
    Digitale Medien
    Digitale Medien
    Environmental effects on cytoplasmic incompatibility and bacterial load in Wolbachia-infected Drosophila simulans (1998)
    Springer
    Entomologia experimentalis et applicata 86 (1998), S. 13-24 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Drosophila ; cytoplasmic incompatibility ; Wolbachia ; temperature ; antibiotics ; density
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of high temperatures, antibiotics, nutrition and larval density on cytoplasmic incompatibility caused by a Wolbachia infection were investigated in Drosophila simulans. Exposure of larvae from an infected stock to moderate doses of tetracycline led to complete incompatibility when treated females were crossed to infected males; the same doses only caused a partial restoration of compatibility when treated males were crossed to uninfected females. In crosses with treated females, there was a strong correlation between dose effects on hatch rates and infection levels in embryos produced by these females. Ageing and rearing males at a high temperature led to increased compatibility. However, exposing infected females to a high temperature did not influence their compatibility with infected males. Male temperature effects depended on conditions experienced at the larval stage but not the pupal stage. Exposure to 25 °C reduced the density of Wolbachia in embryos compared with a 19 °C treatment. Low levels of nutrition led to increased compatibility, but no effect of larval crowding was detected. These findings show the ways environmental factors can influence the expression of cytoplasmic incompatibility and suggest that environmental effects may be mediated by bacterial density.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003043814761
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  • 6
    Digitale Medien
    Digitale Medien
    Different responses to temperature in three closely-related sympatric cereal aphids (1998)
    Springer
    Entomologia experimentalis et applicata 86 (1998), S. 49-58 
    Details
    ISSN: 1570-7458
    Schlagwort(e): aphids ; Sitobion ; population ; chromosomal race ; mean relative growth rate ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Chromosomal races of the aphid Sitobion miscanthi (Takahashi), and a closely-related species S. near fragariae (Aphididae: Macrosiphini) show seasonal differences in abundance in eastern Australia. We tested whether this was related to differences in temperature response, using controlled laboratory conditions. Intrinsic rate of increase, rm, mean relative growth rate (MRGR), and longevity were compared at different temperatures, and rates of increase were compared outdoors under ambient conditions. Using laboratory data, we simulated population growth, for comparison with outdoor populations. There were significant differences in responses to temperature regimes both in the laboratory and outdoors. Outdoor populations fell well short of predicted sizes. S. miscanthi (2n=18) showed evidence of adaptation to warmer conditions. In contrast, S. nr fragariae showed consistent evidence for adaptation to cooler conditions, and S. miscanthi 2n=17 was approximately intermediate. These data indicate that temperature responses are important in the ecology, evolution and pest status of S. miscanthi clones and S. nr fragariae in Australia.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003102927699
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  • 7
    Digitale Medien
    Digitale Medien
    Flight behavior of pre- and postdiapause apple blossom weevils in relation to ambient temperature (1998)
    Springer
    Entomologia experimentalis et applicata 88 (1998), S. 97-99 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Coleoptera ; Curculionidae ; Anthonomus pomorum ; temperature ; diapause ; flight behavior
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003269621622
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  • 8
    Digitale Medien
    Digitale Medien
    Diapause survival and post-diapause performance in bumblebee queens (Bombus terrestris) (1998)
    Springer
    Entomologia experimentalis et applicata 89 (1998), S. 207-214 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Bombus terrestris ; bumblebees ; diapause ; survival ; preoviposition period ; weight ; temperature ; diapause duration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Diapause survival and post-diapause performance (i.e., if a queen starts to lay eggs) of in total 2210 bumblebee queens (Bombus terrestris) were measured under different diapause regimes: 5 temperatures (−5, 0, 5, 10 and 15 °C) in combination with 5 durations of exposure (1, 2, 4, 6 and 8 months). The results show that weight at the start of diapause determines to a large extent whether a queen will be able to survive diapause. Queens with a wet weight below 0.6 g prior to diapause did not survive, but for those queens exceeding this threshold a higher pre- diapause weight did not increase their post-diapause performance. There was no effect of temperature on diapause survival; 76% of the variance in survival could be explained by the duration of the treatment. Neither temperature nor duration of exposure had an effect on post-diapause performance. The preoviposition period of the queens that laid eggs was also determined. The preoviposition period was affected by both temperature and duration of exposure: the preoviposition period decreased with decreasing temperature but also with increasing duration of the treatment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003595306816
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  • 9
    Digitale Medien
    Digitale Medien
    The relative performance of pheromone and light traps in monitoring the seasonal activity of both sexes of the eastern hemlock looper, Lambdina fiscellaria fiscellaria (1998)
    Springer
    Entomologia experimentalis et applicata 89 (1998), S. 87-98 
    Details
    ISSN: 1570-7458
    Schlagwort(e): seasonal trapping ; light traps ; pheromone traps ; trapping periodicity ; temperature ; reproductive state ; eastern hemlock looper
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The seasonal flight activity of both sexes of the eastern hemlock looper, Lambdina fiscellaria fiscellaria Guenée (Lepidoptera: Geometridae) was studied during two consecutive years in Quebec and Newfoundland, using light (L), pheromone (P) and combined light and pheromone (LP) traps. Moth density significantly affected the performance of the different traps, with P traps being more effective at low than high density. However, P trap catches decreased just prior to the onset of female captures, probably as a result of competition between traps and virgin calling females. Nearly all females caught in L and LP traps were already mated and even the first females caught had laid at least half of their egg complement. In Quebec under warm nights, the pattern of male activity occurred at different times, with peak P catches being later in the scotophase than those of L traps, but overall similar numbers of males were caught in both traps. In contrast, under cool nights, males were caught early in the night in both P and L traps, suggesting a strong competition effect between traps, although more males were caught in P than L traps overall. In Newfoundland, the pattern of male captures in L and P traps was similar at both high and low temperatures, so competition between trap types would always be high. Under these conditions P traps were more effective than L traps. Irrespective of the region, year or temperature, significantly more males were captured in LP, with the effect of L and P being additive. In both regions, females responded similarly to L and LP traps with peak activity occurring early in the night. Captures of females were lower than those of males under cool temperatures, suggesting that the temperature threshold for flight is higher for females. The use of L and P traps simultaneously and/or in combination is discussed in relation to integrated pest management programs and ecological considerations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003450432755
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  • 10
    Digitale Medien
    Digitale Medien
    First and second thermodynamic mixing properties of ethylbenzene +n-alkanes: Experimental and theory (1990)
    Springer
    Journal of solution chemistry 19 (1990), S. 1137-1151 
    Details
    ISSN: 1572-8927
    Schlagwort(e): Ethylbenzene ; excess entalphy ; excess volume ; experimental ; heat capacity ; isobaric expansibility ; isentropic and isothermal compressibility ; liquid mixtures ; mixing function ; n-alkanes ; n-hexadecane ; n-tetradecane ; pressure ; temperature ; theory
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Isobaric expansibilities α P and isothermal compressibilities κ T have been determined at 25 and 45°C for binary mixtures of ethylbenzene + n-tetradecane and + n-hexadecane and the corresponding excess functions (∂V E /∂T)P and (∂V E /∂P)T have also been obtained. With these data and supplementary literature values, the following second order mixing properties are also reported at 25°C: κ S E , (∂V E /∂P)T, ΔCV and Δ(ΔγVT). All mixing quantities have been compared with the results obtained at 25°C by using the Prigogine-Flory-Patterson theory of liquid mixtures. The predicted values suggest that the ability of ethylbenzene as a breaker of the pure n-Cn orientations is similar to what we found for toluene and higher than for p-xylene.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00649458
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  • 11
    Digitale Medien
    Digitale Medien
    Voltammetric Analysis of Iodide and Diffusion Coefficients Between 25 and 85°C (1998)
    Springer
    Journal of solution chemistry 27 (1998), S. 373-393 
    Details
    ISSN: 1572-8927
    Schlagwort(e): Iodide ; voltammetry ; diffusion coefficients ; temperature ; Stokes–Einstein equation ; solvation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The oxidation wave of iodide in 0.075 mol-L−1 H2SO4 was analyzed at 25, 40, 55, 70, and 85°C. The reversibility of the I2/I− system was checked using logarithmic transforms, half-wave potentials, and by studying I −1 = f(ω−1/2). The limiting currents obtained enabled us to determine the diffusion coefficient of I− using Newman's equation. These experimental results were compared with Nernst's limiting values. The Stokes–Einstein equation is not verified. Hydration numbers for I− at different temperatures were established. An empirical equation is proposed to predict the evolution of diffusion coefficients in a sulfuric acid medium with temperature.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022679716395
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  • 12
    Digitale Medien
    Digitale Medien
    Eucaryotic codes (1990)
    Springer
    Cellular and molecular life sciences 46 (1990), S. 1106-1117 
    Details
    ISSN: 1420-9071
    Schlagwort(e): Genetic code ; eucaryotic cell ; evolution ; code ambiguity ; code universality ; convergence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary This article is a review of the rules used by eucaryotic cells to translate a nuclear messenger RNA into a polypeptide chain. The recent observation that these rules are not identical in two species of a same phylum indicates that they have changed during the course of evolution. Possible scenarios for such changes are presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01936920
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  • 13
    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
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  • 14
    Digitale Medien
    Digitale Medien
    Basic rules of change (1990)
    Springer
    Journal for general philosophy of science 21 (1990), S. 231-257 
    Details
    ISSN: 1572-8587
    Schlagwort(e): basic rules ; change ; discipline-neutral ; evolution ; analogy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Philosophie , Wissenschaftskunde und Wissenschaftsorganisation, Hochschul- und Universitätswesen, Museumswissenschaft
    Notizen: Summary A small step is made in the direction of defining some general basic rules which can serve as a framework for research in several fields of the social sciences. The method of working with analogies asks for a more accurate approach. Starting from the concept of evolution in the form of a basic rule another basic rule is formulated. This rule shows what are the most important factors in long term developments and what types of development one can expect.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01801037
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  • 15
    Digitale Medien
    Digitale Medien
    Effect of the presence of olive fruit on ovarian maturation in the olive fruit fly, Dacus oleae, under laboratory conditions (1990)
    Springer
    Entomologia experimentalis et applicata 55 (1990), S. 161-168 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Tephritidae ; Dacus oleae ; olive fruit fly ; ovarian maturation ; olive fruit ; diapause ; photoperiod ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé La maturation ovarienne des femelles adultes agées de 7, 22–23 et 28 jours de D. oleae ayant accompli leur développement embryonnaire, larvaire et nymphal en LD 12:12, 19±1°C et maintenues en LD 16:8, 26±1°C, sans accès à des olives, est inhibée. Dans les mêmes conditions, mais avec accès permanent à des olives, 54% des femelles ont des ovocytes mûrs à 7 jours, 87% à 22–23 jours et 100% à 28 jours. Avec des femelles ayant accès à des domes de paraffine, les pourcentages d'individus ayant des ovocytes mûrs sont intermédiaires entre ceux des deux situations précédentes. Dans les conditions cidessus défavorables à la maturation ovarienne, 50% des femelles de 28 jours ont des ovocytes mûrs si elles sont en présence d'olives durant leur première semaine de vie imaginale et 91% si elles sont en présence la 4éme semaine. Les pourcentages respectifs concernant les femelles pourvues de dômes de paraffine sont encore intermédiaires entre ceux des femelles avec olives et ceux de femelles privées de tout substrat. La présence d'olives a aussi un effet fortement positif sur la maturation ovarienne de femelles ayant accompli leur développement pre-imaginal et maintenues aussi à l'etat adulte en conditions LD 16:8, 26±1°C, favorisant la maturation ovarienne. L'accès à des dômes de paraffine a, là encore, un effet intermédiaire. On conclut par conséquent que la non maturation ovarienne des femelles de D. oleae qui est causée par une photopériode à jour court pendant la vie pre-imaginale accompagné par une photopériode à jour long et une augmentation de la température pendant la vie imaginale persiste au moins jusqu'à la fin de la quatrième semaine de la vie imaginale en absence d'olives, mais ne se produit pas si on met les femelles adultes en présence d'olives.
    Notizen: Abstract Ovarian maturation was prevented in 7-, 22-, 23- and 28-day-old females of Dacus oleae (Gmelin) (Diptera: Tephritidae), developed in the pre-imaginal stages at LD 12:12, 19±1°C and kept as adults at LD 16:8, 26±1°C without access to olive fruits. In females of the above ages having continuous access to olive fruits and held under the same photoperiod and temperature conditions, 54, 87 and 100%, respectively, had mature oocytes. When the females had access to domes of paraffin wax, the percentages of females with mature oocytes were intermediate between those with and those without access to olive fruits. Under the above photoperiod and temperature conditions unfavorable for maturation, 50% of 4-week-old females had mature oocytes if exposed for one week to olive fruits during their first week and 91% if exposed during their 4th week of adult life. The respective percentages with wax domes in the cages were again intermediate between those with olives and those without olives or wax domes. The presence of olive fruits had also a strong positive effect on the ovarian maturation of females which developed from egg through the adult stage at LD 16:8, 26±1°C, a condition favoring ovarian maturation. Access to wax domes had again an intermediate effect on maturation. It is concluded therefore that the lack of ovarian maturation of D. oleae females which is observed under a short photophase during the pre-imaginal stages if followed by a long photophase and an increase of temperature during the adult stage, continues at least till the end of the 4th week of adult life in the absence of olive fruits but is averted when such fruits are offered to the adult flies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00352577
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  • 16
    Digitale Medien
    Digitale Medien
    Evolutionary genetics of the aphid Cryptomyzus, with a preliminary analysis of the inheritance of host plant preference, reproductive performance and host-alteration (1990)
    Springer
    Entomologia experimentalis et applicata 57 (1990), S. 65-76 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Cryptomyzus ; aphid ; hybridization ; host plant preference ; reproductive performance ; host-alternation ; speciation ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé C. galeopsidis Kaltenbach contient plusieurs formes qui ont différentes relations avec des plantes hôtes et des cycles distincts. Des croisements ont permis d'élucider la taxonomie de ces formes et d'étudier l'hérédité de préférences d'hôtes, des performances reproductives et de l'alternance d'hôtes. Une des formes apparaît comme une espèce distincte par suite de la valeur adaptative réduite des hybrides. Les autres formes avec alternance ou non des hôtes sont considérées comme conspécifiques et représentant deux stratégies vitales différentes. Les performances reproductives sont probablement polygéniques puisque les hybrides ont des performances intermédiaires. Les préférences d'hôtes des hybrides montrent certains degrés de dominance et semblent déterminées par quelques gènes seulement. L'alternance des hôtes est envisagée comme ayant une hérédité monofactorielle. Les conséquences sur la spéciation sont discutées.
    Notizen: Abstract The aphid species Cryptomyzus galeopsidis (Kaltenbach) includes several distinct forms which have different host plant relationships and life cycles. Cross breeding was used to elucidate the taxonomic status of these forms and to investigate the inheritance of host preference, reproductive performance and host-alternation. One of the forms appeared to be a distinct species because of the reduced fitness of the hybrids. Other host-alternating and non host-alternating forms are considered conspecific and represent two life cycle strategies. Reproductive performance is probably controlled polygenically, since hybrids show an intermediate performance. Host preference in hybrids showed some degree of dominance and seemed to be determined by only a few genes. Host-alternation is presumed to be inherited monofactorially. The implications for speciation are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00349596
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  • 17
    Digitale Medien
    Digitale Medien
    Thermoelastic contact problem of two rotating bodies with frictional heat generation in annular region (1998)
    Springer
    Archive of applied mechanics 68 (1998), S. 128-136 
    Details
    ISSN: 1432-0681
    Schlagwort(e): Key words frictional heating ; temperature ; contact pressure ; punch indentation ; thermoelasticity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Summary An axisymmetric contact problem with frictional heating is considered in which a parabolic annular punch is pressed into a plane surface and rotates about its axis of symmetry at constant speed. The problem is formulated in terms of one governing equation with unknown pressure. This equation is solved numerically. The change of the geometry of the contact region and pressure has been investigated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004190050150
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  • 18
    Digitale Medien
    Digitale Medien
    Carbon and nitrogen mineralization characteristics of organic nitrogen fertilizers in a soil-less incubation system (1990)
    Springer
    Nutrient cycling in agroecosystems 23 (1990), S. 97-103 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Carbon ; mineralization ; nitrogen ; organic fertilizer ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The C and N mineralization characteristics of two organic N fertilizers were determined in a soil-less incubation system at three temperature regimes. Protox (derived from activated sewage sludge) initially degraded more rapidly by microbial action compared with dried blood. However, dried blood released more CO2-C and inorganic N towards the end of the incubation periods. The rate of microbial degradation increased with temperature. Mineralization characteristics of protein-based N sources are discussed in relation to organic N nutrition of vegetable crops.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01063336
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  • 19
    Digitale Medien
    Digitale Medien
    Comparison of industrial and high-resolution thermal data in a sedimentary basin (1990)
    Springer
    Pure and applied geophysics 133 (1990), S. 251-267 
    Details
    ISSN: 1420-9136
    Schlagwort(e): Heat flow ; sediments ; temperature ; gradients ; conductivity ; industrial data ; scientific data ; hydrodynamics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Temperature, temperature gradient and heat flow, derived from four wells in the Western Canada Sedimentary Basin have been compared with similar quantities derived from maps constructed from industrial data. Individual industrial temperature data may differ from the high-resolution temperature log by up to 30 K, but linear regression of the collected data agrees within 10 K at all points observed. Some evidence suggests that measured conductivities, using drill-cuttings, are biased toward average values. Derived heat flows show agreement of heat flow within 10% within the Mesozoic section. In the Paleozoic section differences are greater, and more varied, with insufficient data for general conclusions. Both styles of measurement provide opportunities for interpretation, each contributing to thermal analysis of sedimentary basins.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00877162
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  • 20
    Digitale Medien
    Digitale Medien
    The genetic code in mitochondria and chloroplasts (1990)
    Springer
    Cellular and molecular life sciences 46 (1990), S. 1117-1126 
    Details
    ISSN: 1420-9071
    Schlagwort(e): Genetic code ; mitochondria ; evolution ; organelles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The universal genetic code is used without changes in chloroplasts and in mitochondria of green plants. Non-plant mitochondria use codes that include changes from the universal code. Chloroplasts use 31 anticodons in translating the code; a number smaller than that used by bacteria, because chloroplasts have eliminated 10 CNN anticodons that are found in bacteria. Green plant mitochondria (mt) obtain some tRNAs from the cytosol, and genes for some other tRNAs have been acquired from chloroplast DNA. The code in non-plant mt differs from the universal code in the following usages found in various organisms: UGA for Trp, AUA for Met, AGR for Ser and stop, AAA for Asn, CUN for Thr, and possibly UAA for Tyr. CGN codons are not used byTorulopsis yeast mt. Non-plant mt, e.g. in vertebrates, may use a minimum of 22 anticodons for complete translation of mRNA sequences. The following possible causes are regarded as contributing to changes in the non-plant mt: directional mutation pressure, genomic economization, changes in charging specificity of tRNAs, loss of release factor RF2, changes in RF1, changes in anticodons, loss of lysidine-forming enzyme system, and disappearance of codons from coding sequences.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01936921
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  • 21
    Digitale Medien
    Digitale Medien
    The fractal lung: Universal and species-related scaling patterns (1990)
    Springer
    Cellular and molecular life sciences 46 (1990), S. 251-254 
    Details
    ISSN: 1420-9071
    Schlagwort(e): Bronchial tree ; evolution ; fractal ; lung airway ; morphogenesis ; renormalization group theory
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The mammalian lung exhibits features of a fractal tree: heterogeneity, self-similarity and the absence of a characteristic scale. The finite nature of the lung ultimately limits the range over which self-similarity scaling characteristics are applicable. However, generalization based on the scaling features of fractals, provides unique insight into geometric organization of anatomic structures. Furthermore, the mathematical theory of renormalization groups provides a description of the harmonically-modulated inverse power-law scaling observed for bronchial tree dimensions observed in different species. Compared to several mammalian species (dog, rat, hamster), the human lung shows marked differences in the phase of the harmonic modulation for both length and diameter measurements. These inter-species scaling differences suggest that evolutionary factors modify certain universal features of morphogenesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01951755
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  • 22
    Digitale Medien
    Digitale Medien
    Thermodynamics of Polyvinylacetate from 0 to 350 K (1998)
    Springer
    Journal of thermal analysis and calorimetry 54 (1998), S. 731-740 
    Details
    ISSN: 1572-8943
    Schlagwort(e): enthalpy ; entropy ; Gibbs energy ; heat capacity ; limiting polymerization temperature ; polyvinylacetate ; temperature ; thermodynamics of polymerization ; vinyl acetate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The temperature dependence of the heat capacity of vinyl acetate in the range 13 to 330 K and of polyvinylacetate between 4.9 and 330 K was determined by adiabatic vacuum calorimetry with an error of about 0.2%. Temperatures and enthalpies of physical transitions were measured. From the data obtained, the thermodynamic characteristics of melting of vinyl acetate and parameters of glass transition and glassy state of the monomer and polymer were calculated. The thermodynamic functions Ho(T)-Ho(0), So(T), Go(T)-Ho(0) were estimated for both materials from 0 to 350 K. The results of calculation and the literature value of enthalpy of bulk polymerization of vinyl acetate at T=350 K were used for the estimation of the thermodynamic parameters of its polymerization process ΔHpol o, ΔSpol o, ΔGpol oin the interval 0 to 350 K. A ceiling limiting temperature of polymerization Tceil owas evaluated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010179517532
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  • 23
    Digitale Medien
    Digitale Medien
    The evolution of the mammalian Y chromosome (1990)
    Springer
    Behavior genetics 20 (1990), S. 109-126 
    Details
    ISSN: 1573-3297
    Schlagwort(e): Y chromosome ; DNA ; mammals ; evolution ; behavior
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract There is a predominant theory for the evolution of the mammalian Y chromosome. This theory hypothesizes that genes for sex determination and male-specific traits, as well as sequences for X-Y meiotic pairing, are conserved on the mammalian Y chromosome across all lineages and that all other Y chromosomal genes or sequences have been or will be lost in each mammalian lineage. There are effects of mouse Y chromosomal genes on behaviors and other traits that are not male specific. Under the predominant theory, these Y chromosomal genes could be the same as the conserved genes for sex determination or malespecific traits, or they could be genes that have been lost from the Y chromosomes of other mammalian lineages and that will eventually be lost from the Y chromosome of the rodent lineage. Recently, the evolution of the primate and rodent Y chromosomes has been studied at the DNA level. These studies are summarized and reviewed in this article. The findings of these studies are not fully consistent with the predominant theory for the evolution of the mammalian Y chromosome. Also, they imply that there are other possibilities for the phylogenetic history of Y chromosomal genes of mice with effects on behavior. These are that Y chromosomal genes with effects on mouse behaviors or other traits could be conserved genes other than those for sex determination or malespecific traits or that they could be novel genes on the Y chromosome of the rodent orMus lineage.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01070748
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  • 24
    Digitale Medien
    Digitale Medien
    Evolution of the glycophorin gene family in the hominoid primates (1990)
    Springer
    Biochemical genetics 28 (1990), S. 209-222 
    Details
    ISSN: 1573-4927
    Schlagwort(e): glycophorin A ; glycophorin B ; evolution ; primates ; chimpanzee ; gorilla ; orangutan ; gibbon
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Analysis of nucleotide sequences of the human glycophorin A (GPA) and glycophorin B (GPB) genes has indicated that the GPA gene most closely resembles the ancestral gene, whereas the GPB gene likely arose from the GPA gene by homologous recombination. To study the evolution of the glycophorin gene family in the hominoid primates, restricted DNA on Southern blots from man, pygmy chimpanzee, common chimpanzee, gorilla, orangutan, and gibbon was probed with cDNA fragments encoding the human GPA and GPB coding and 3′-untranslated regions. This showed the presence in all of the hominoid primates of at least one GPA-like gene. In addition, at least one GPB-like gene was detected in man, both chimpanzee species, and gorilla, strongly suggesting that the event that produced the GPB gene occurred in the common ancestor of man-chimpanzee-gorilla. An unexpected finding in this study was the conservation ofEcoRI restriction sites relative to those of the other four enzymes used; the significance of this observation is unclear, but raises the question of nonrandomness ofEcoRI restriction sites in noncoding regions. Further analysis of the evolution of this multigene family, including nucleotide sequence analysis, will be useful in clarification of the evolutionary relationships of the hominoid primates, in correlation with the structure and function of the glycophorin molecules, and in assessment of the role of evolution in the autogenicity of glycophorin determinants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00561338
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  • 25
    Digitale Medien
    Digitale Medien
    Towards a Predictive Design Methodology Based on the Physical Modelling of the Fracture of Fiber Composites (1998)
    Springer
    Applied composite materials 5 (1998), S. 69-94 
    Details
    ISSN: 1573-4897
    Schlagwort(e): modelling ; notch strength ; damage ; fatigue ; environment ; temperature ; prediction ; design
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract A predictive design methodology based on modelling the fracture stress (notched tensile strength) and post-fatigue residual strength of laminated fiber composites is presented. The approach is based explicitly on the development of models of the physical processes by which damage accumulates at a notch-tip and the application of these models to cross-ply laminates for a variety of material systems, including thermosetting and thermoplastic matrices containing carbon, glass and Kevlar fiber reinforcements. The effects of temperature and humidity on composite fracture can also be examined in the context of this modelling strategy. A pre-requisite of the model is that it has to be calibrated for each material system by performing tensile tests on notched and unnotched cross-ply laminate. From this initial calibration, which takes relatively little time, it is possible to apply the model to a prediction of the dependence of fracture stress on notch size; to an understanding of the effects of laminate stacking sequence (within the same cross-ply family) on fracture stress; and to provide insight into the effects of thermal or load cycling history on fatigue damage-growth and residual or fatigue strength. The advantages and deficiencies of this modelling strategy are assessed, as well as the applicability of such a physical modelling approach to the predictive design and failure of composite materials in general.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008811721083
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  • 26
    Digitale Medien
    Digitale Medien
    The gene coding for glutamate dehydrogenase inDrosophila melanogaster (1990)
    Springer
    Biochemical genetics 28 (1990), S. 337-346 
    Details
    ISSN: 1573-4927
    Schlagwort(e): glutamate dehydrogenase ; Drosophila melanogaster ; gene expression ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract We have isolated theDrosophila melanogaster locus coding forl-glutamate dehydrogenase (EC 1.4.1.3) by virtue of its similarity to the corresponding human gene. There is only one copy of this gene in the fruit fly genome, located on the right arm of chromosome 3 (95D1-4). The transcript includes at least one large intron and matures to a ∼2.4-kb-long polyadenylated RNA whose expression is under developmental control.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00554064
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  • 27
    Digitale Medien
    Digitale Medien
    Multiple restriction fragment length polymorphisms associated with the Vc determinant of the MN blood group-related chimpanzee V-A-B-D system (1990)
    Springer
    Biochemical genetics 28 (1990), S. 223-231 
    Details
    ISSN: 1573-4927
    Schlagwort(e): restriction fragment length polymorphisms ; glycophorin A ; glycophorin B ; MN blood group ; V-A-B-D blood group ; Vc antigen ; chimpanzee ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Twelve restriction fragment length polymorphisms (RFLPs) were detected in common chimpanzee using two restriction enzymes (HindIII andMspI) and four DNA probes to the coding regions of the human glycophorin A (GPA) and glycophorin B (GPB) genes and their 3′-untranslated regions. Seven RFLPs correlated with red cell expression of the Vc determinant of the MN blood group-related V-A-B-D system and five RFLPs correlated with nonexpression of this antigen. Animals heterozygous for theV allele that encodes the Vc determinant had all 12 polymorphic restriction fragments and appeared to show reduced intensity of probe hybridization to these fragments, consistent with the presence of aV and a non-V allele. No RFLPs were detected withEcoRI,SstI, orBamHI, in spite of the relatively large segment of DNA (at least 20 kb) involved in the polymorphisms. The RFLPs were chimpanzee specific and were not found in man, gorilla, orangutan, or gibbon. Multiple RFLPs distinguishing primate species are rare and may be useful markers for molecular evolution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00561339
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  • 28
    Digitale Medien
    Digitale Medien
    Release rates of tetradecen-1-ol acetates from polymeric formulations in relation to temperature and air velocity (1990)
    Springer
    Journal of chemical ecology 16 (1990), S. 1041-1058 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Air velocity ; controlled release ; formulation ; pheromone ; release rate ; temperature ; tetradecen-1-ol acetates ; vapor collection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract An apparatus was developed for investigating the release rates of pheromone formulations at temperatures and air velocities that correspond with those in the field. Polyurethane foam proved an excellent adsorbent for the recovery of tetradecen-1-ol acetates, allowing high air flows at low differential pressure and without breakthrough of these compounds. The experimental setup and procedures are described. The release rates of all formulations investigated were almost proportional to the square root of air velocity, and their logarithms were proportional to the reciprocal of temperature (K). When temperature is increased from 15°C to 25°C, the release rates increase by about 2-2.5 ×. Both relationships were combined into one equation that allows a reliable estimate to be made of the actual release rates of a formulation, under varying conditions, on the basis of its specific parameters and the relevant meteorological data.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01021009
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  • 29
    Digitale Medien
    Digitale Medien
    Hierarchical Bayesian space-time models (1998)
    Springer
    Environmental and ecological statistics 5 (1998), S. 117-154 
    Details
    ISSN: 1573-3009
    Schlagwort(e): atmospheric science ; dynamical systems ; environmental studies ; Gibbs sampling ; Markov random field ; MCMC ; non-stationarity ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Space-time data are ubiquitous in the environmental sciences. Often, as is the case with atmo- spheric and oceanographic processes, these data contain many different scales of spatial and temporal variability. Such data are often non-stationary in space and time and may involve many observation/prediction locations. These factors can limit the effectiveness of traditional space- time statistical models and methods. In this article, we propose the use of hierarchical space-time models to achieve more flexible models and methods for the analysis of environmental data distributed in space and time. The first stage of the hierarchical model specifies a measurement- error process for the observational data in terms of some 'state' process. The second stage allows for site-specific time series models for this state variable. This stage includes large-scale (e.g. seasonal) variability plus a space-time dynamic process for the ’anomalies'. Much of our interest is with this anomaly proc ess. In the third stage, the parameters of these time series models, which are distributed in space, are themselves given a joint distribution with spatial dependence (Markov random fields). The Bayesian formulation is completed in the last two stages by speci- fying priors on parameters. We implement the model in a Markov chain Monte Carlo framework and apply it to an atmospheric data set of monthly maximum temperature.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009662704779
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  • 30
    Digitale Medien
    Digitale Medien
    The gene coding for glutamate dehydrogenase inDrosophila melanogaster (1990)
    Springer
    Biochemical genetics 28 (1990), S. 337-346 
    Details
    ISSN: 1573-4927
    Schlagwort(e): glutamate dehydrogenase ; Drosophila melanogaster ; gene expression ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract We have isolated theDrosophila melanogaster locus coding forl-glutamate dehydrogenase (EC 1.4.1.3) by virtue of its similarity to the corresponding human gene. There is only one copy of this gene in the fruit fly genome, located on the right arm of chromosome 3 (95D1-4). The transcript includes at least one large intron and matures to a ∼2.4-kb-long polyadenylated RNA whose expression is under developmental control.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02401423
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  • 31
    Digitale Medien
    Digitale Medien
    Personality and reproductive fitness (1990)
    Springer
    Behavior genetics 20 (1990), S. 563-568 
    Details
    ISSN: 1573-3297
    Schlagwort(e): personality ; fertility ; family size ; fitness ; extraversion ; neuroticism ; impulsivity ; genetic architecture ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract The relationship between reproductive success (number of biological children) and personality was explored in 1101 postmenopausal females from the Australian twin registry. The quadratic response surface relating fitness to extraversion (E) and neuroticism (N) showed a saddle point at intermediate levels of E and N. Selection was shown to be stabilizing, i.e.,having an intermediate optimum, along the axis low E, low N-high E, high N and more mildly disruptive, having greater fitness in the extremes, along the axis low N, high E-high N, low E. Neither dimension of personality considered by itself showed a significant linear or quadratic relationship to reproductive success. Sections through the fitness surface, however, show selection tends to favor high neuroticism levels in introverts and low neuroticism levels in extroverts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01065872
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  • 32
    Digitale Medien
    Digitale Medien
    Raman spectroscopic studies of hen egg-white lysozyme at high temperatures and pressures (1990)
    Springer
    The protein journal 9 (1990), S. 475-486 
    Details
    ISSN: 1573-4943
    Schlagwort(e): Lysozyme ; pressure ; temperature ; Raman
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In situ high-temperature, high-pressure Raman experiments on 3 mM (pH 5) aqueous solutions of hen egg-white (HEW) lysozyme show a decrease in the relative height of the 505 cm−1 band associated with S-S stretching vibrations at 72°C (1 bar). The peak height changes are accompanied by significant band broadening, and the integrated band intensity does not change within experimental error. The effect of increased pressure at 72°C was to hinder broadening of the 505 cm−1 band. HEW lysozyme (2.4 mM,pH 5) was also heated at 76°C, 80°C, and 95°C for different periods of time, and aliquots were quenched to room temperature for Raman and enzymatic activity measurements. After 9 hr at 76°C, the protein exhibits enzyme activity less than 50% of the initial value, and approximately 50% reduction in activity is achieved after 3 hr at 80°C or 1 hr at 95°C. The Raman results suggest that different irreversibly denatured conformations are attained during prolonged exposures at these different temperatures. It is apparent from these studies that the S-S stretch intensity is decreased irreversibly.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01024624
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  • 33
    Digitale Medien
    Digitale Medien
    Rapid multiplication of potatoes in the warm tropics: rooting and establishment of cuttings (1990)
    Springer
    Potato research 33 (1990), S. 13-21 
    Details
    ISSN: 1871-4528
    Schlagwort(e): hormones ; media ; phosphorus ; rooting depth ; solar radiation ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary To expand potato production in developing countries using cuttings as a source of good quality planting material, requires simple low cost methods to root and establish them. Experiments at a warm tropical site in the Philippines, to determine appropriate methods, showed that simple media ranging from fine sand to clay subsoil mixed with rice hulls enabled rooting which was not improved by hormones. Nitrogen rich media, such as volcanic soil or compost with additional P, were best for developing cuttings into strong transplants but there were no major differences in root and shoot development from cuttings differing in size and age. Tuberizations was favored by increasing the number of nodes buried in the media. Low solar radiation of 7 MJ/m2/day enabled high cutting survival up to root initiation, after which higher radiation supported larger root and shoot production.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02358126
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  • 34
    Digitale Medien
    Digitale Medien
    Phylogenetic relationships and gene flow between sympatric diploid and tetraploid plants ofDactylis glomerata (Gramineae) (1990)
    Springer
    Plant systematics and evolution 169 (1990), S. 81-96 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Gramineae ; Festuceae ; Dactylis glomerata ; Enzymatic markers ; phenology ; interploid exchanges ; autopolyploidy ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Phylogenetic relationships between sympatric, morphologically indistinguishable diploid and tetraploid plants ofDactylis glomerata L. (Gramineae) in Galicia (Spain) were assessed using allozyme markers for 6 distinct systems. The study exploited recent introduction in Galicia and subsequent hybridization of an alien 4xDactylis subspecies possessing distinct allozymes from those of all the native plants. Opportunities for gene exchanges between the ploidies were estimated from in situ observations of flowering, examination of progenies in 2x/4x natural and experimental crosses, and enzyme analyses. Results show a high genetic similarity between the Galician diploids and tetraploids, which possess peculiar alleles in common. Although the ploidy levels usually have distinct flowering periods, interploidal crosses do occasionally occur. Gene flow is likely much more important from the diploid to the tetraploid level. A good genetic intermixing occurs between the Galician and the alien tetraploid entities which have simultaneous flowering. Autopolyploidization of the diploids followed by various rates of hybridization is proposed as one very probable origin of natural tetraploids inDactylis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00935987
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  • 35
    Digitale Medien
    Digitale Medien
    Evolution of genome size inAllium (Alliaceae) (1998)
    Springer
    Plant systematics and evolution 210 (1998), S. 57-86 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Alliaceae ; Allium ; Nuclear DNA amount ; adaptation ; evolution ; infrageneric classification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The 4C DNA amounts of 86 species fromAllium subgg.Allium, Rhizirideum, Bromatorrhiza, Melanocrommyum, Caloscordum andAmerallium show a 8.35-fold difference ranging from 35.60 pg (A. ledebourianum, 2n = 16) to 297.13 pg (A. validum 2n = 56). At diploid level the difference is 3.57-fold betweenA. ledebourianum (35.60 pg) andA. ursinum (127.14 pg). This shows that a significant loss and/or gain of DNA has occurred during evolution. On average subgg.Rhizirideum andAllium have less DNA amount than subgg.Melanocrommyum andAmerallium. The distribution of nuclear DNA amounts does not show discontinuous pattern and regular groups. The evolution of genome size has been discussed in relation to polyploidy and genomes, heterochromatin, adaptive changes in morphological characteristics, phenology and ecological factors, and infrageneric classification.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00984728
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  • 36
    Digitale Medien
    Digitale Medien
    Response of the tropical red seaweed Gracilaria cornea to temperature, salinity and irradiance (1998)
    Springer
    Journal of applied phycology 10 (1998), S. 419-425 
    Details
    ISSN: 1573-5176
    Schlagwort(e): Gracilaria cornea ; photosynthesis ; respiration ; chlorophyll ; phycoerythrin ; Florida ; salinity ; temperature ; irradiance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The agarophyte Gracilaria cornea, collected over 2.5 y in the Florida Keys, shows adaptations to oceanic salinities and subtropical to tropical water temperatures in its photosynthetic and respiratory responses as measured with a respirometer. No seasonal pattern in responses to irradiance, temperature, and salinity were evident between five collections over a 20-month period, indicating the tropical nature of the populations from Bahia Honda and Pigeon Keys. Concentrations of chlorophyll a (0.09 to 0.41 mg g d wt-1) and phycoerythrin (0.06 to 0.36 mg g d wt- 1) were low and reflect the low nutrient regime of the habitats, especially when compared to laboratory cultured plants. Compensation and saturation irradiances were also low (11–38 and 90–127 μmol photon m-2 s-1), indicating acclimation to lower irradiances in their shallow (1–2 m depth) habitats where turbidity can be high. In comparison with other subtropical and warm temperate species of Gracilaria, G. cornea had lower levels of pigment, but similarly high photosynthetic efficiency, demonstrating shade adaptation; it had only limited tolerance to salinities below 20‰ and temperatures below 15 °C. Thus, G. cornea from the Florida Keys in mariculture would require subtropical to tropical temperatures and stable oceanic salinities.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008021613399
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  • 37
    Digitale Medien
    Digitale Medien
    Genetic markers, genealogies and biogeographic patterns in the cladocera (1998)
    Springer
    Aquatic ecology 32 (1998), S. 37-51 
    Details
    ISSN: 1573-5125
    Schlagwort(e): microcrustaceans ; Daphnia ; evolution ; interspecific hybridization ; molecular systematics ; aquatic ecology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cladoceran crustaceans are an important component of zooplankton in a wide range of freshwater habitats. Although the ecological characteristics of several cladoceran species have been well studied, biogeographical studies have been hampered by problematic taxonomic affiliations. However, recently developed molecular techniques, provide a powerful tool to subject aquatic taxa to comparative analyses. Here we highlight recent molecular approaches in aquatic ecology by presenting a simple method of DNA preparation and PCR amplification of the mitochondrial DNA (16S rDNA) in species from nine different families within the cladocera. On a broad taxonomic scale, sequence analysis of this mtDNA fragment has been used to produce the first molecular based phylogeny of the cladocera. This analysis clustered the cladoceran families in a fashion similar to that suggested by previous systematic classifications. In a more detailed analysis of the family Daphniidae, nuclear randomly amplified polymorphic DNA (RAPD), mitochondrial restriction fragment length polymorphism (RFLP) and morphological analyses were combined to identify species and interspecific hybrids within the Daphnia galeata species complex across 50 lakes in 13 European countries and one lake in Africa. The study revealed interspecific hybridization and backcrossing between some taxa (D. cucullata and D. galeata) to be widespread, and species and hybrids to frequently occur in sympatry. Genetic, as well as morphological information, suggests the occurrence of D. hyalina outside the Holarctic.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009939901198
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  • 38
    Digitale Medien
    Digitale Medien
    Modeling in the museum: On the role of remnant models in the work of Joseph Grinnell (1990)
    Springer
    Biology and philosophy 5 (1990), S. 3-36 
    Details
    ISSN: 1572-8404
    Schlagwort(e): Material models ; semantic view of theories ; natural history ; ecology ; evolution ; museums ; Joseph Grinnell
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Abstract Accounts of the relation between theories and models in biology concentrate on mathematical models. In this paper I consider the dual role of models as representations of natural systems and as a material basis for theorizing. In order to explicate the dual role, I develop the concept of a remnant model, a material entity made from parts of the natural system(s) under study. I present a case study of an important but neglected naturalist, Joseph Grinnell, to illustrate the extent to which mundane practices in a museum setting constitute theorizing. I speculate that historical and sociological analyses of institutions can play a specific role in the philosophical analysis of model-building strategies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02423831
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  • 39
    Digitale Medien
    Digitale Medien
    Really taking Darwin seriously: An alternative to Michael Ruse's Darwinian metaethics (1990)
    Springer
    Biology and philosophy 5 (1990), S. 149-173 
    Details
    ISSN: 1572-8404
    Schlagwort(e): Darwinian ethics ; ethics ; evolution ; evolutionary ethics ; M. Ruse ; naturalistic fallacy ; sociobiology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Abstract Michael Ruse has proposed in his recent book Taking Darwin Seriously and elsewhere a new Darwinian ethics distinct from traditional evolutionary ethics, one that avoids the latter's inadequate accounts of the nature of morality and its failed attempts to provide a naturalistic justification of morality. Ruse argues for a sociobiologically based account of moral sentiments, and an evolutionary based casual explanation of their function, rejecting the possibility of ultimate ethical justification. We find that Ruse's proposal distorts, overextends and weakens both Darwinism and naturalism. So we propose an alternative Darwinian metaethics that both remedies the problems in Ruse's proposal and shows how a Darwinian naturalistic account of the moral good in terms of human fitness avoids the naturalistic fallacy and can provide genuine, even if limited, justifications for substantive ethical claims. Thus, we propose to really take Darwin seriously.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00127485
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  • 40
    Digitale Medien
    Digitale Medien
    Evolved ethics re-examined: The theory of Robert J. Richards (1990)
    Springer
    Biology and philosophy 5 (1990), S. 451-457 
    Details
    ISSN: 1572-8404
    Schlagwort(e): Auschwitz ; biology ; ethics ; evolution ; moral theory ; naturalistic fallacy ; Richards
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Conclusion Richards's theory, then, fails on three counts. By illegitimately importing a premise from outside of the theory of evolution in order to construct a valid argument, Richards has failed to achieve his objective of deriving a moral theory exclusively from biological facts. By sliding from a causal use of “ought” to a moral one, Richards commits the fallacy of ambiguity. And by insisting that action from the motive of altruism is moral while claiming that an ethical theory which justifies Hitler's camps must be judged false, Richards has falsified his own ethical theory.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02207383
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  • 41
    Digitale Medien
    Digitale Medien
    Buffon, Darwin, and the Non-Individuality of Species – A Reply to Jean Gayon (1998)
    Springer
    Biology and philosophy 13 (1998), S. 443-470 
    Details
    ISSN: 1572-8404
    Schlagwort(e): Buffon ; Darwin ; Gayon ; species ; individuality ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Abstract Gayon's recent claim that Buffon developed a concept of species as physical individuals is critically examined and rejected. Also critically examined and rejected is Gayon's more central thesis that as a consequence of his analysis of Buffon's species concept, and also of Darwin's species concept, it is clear that modern evolutionary theory does not require species to be physical individuals. While I agree with Gayon's conclusion that modern evolutionary theory does not require species to be physical individuals, I disagree with his reasons and instead provide logical rather than historical reasons for the same conclusion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006587726855
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  • 42
    Digitale Medien
    Digitale Medien
    Evolution Without Change in Gene Frequencies (1998)
    Springer
    Biology and philosophy 13 (1998), S. 255-261 
    Details
    ISSN: 1572-8404
    Schlagwort(e): evolution ; speciation ; levels of selection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Abstract Biologists often define evolution as a change in allele frequencies. Consideration of the evolution of the pocket mouse will show that it is possible to have evolution without any change in the allele frequencies in a population (through change in the genotype frequencies). The implications of this for genic selectionism are then discussed. Sober and Lewontin (1982) have constructed an example to demonstrate the “blindness” of genic selectionism in certain cases. Sterelny and Kitcher (1988) offer a defense against these arguments which assumes a conventionalist approach to populations. The example considered here will be shown to offer a more plausible and far-reaching argument against the view that alleles can always be seen as the units of selection.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006541028421
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  • 43
    Digitale Medien
    Digitale Medien
    Taxonomy and Philosophy of Names (1998)
    Springer
    Biology and philosophy 13 (1998), S. 233-244 
    Details
    ISSN: 1572-8404
    Schlagwort(e): reference ; meaning ; individual ; class ; definition ; clade ; evolution ; phylogeny ; phylogenetic taxonomy ; systematics ; tree-thinking ; cladistics ; intention ; extension
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Abstract Although naming biological clades is a major activity in taxonomy, little attention has been paid to what these names actually refer to. In philosophy, definite descriptions have long been considered equivalent to the meaning of names and biological taxonomy is a scientific application of these ideas. One problem with definite descriptions as the meanings of names is that the name will refer to whatever fits the description rather than the intended individual (clade). Recent proposals for explicit phylogenetic definitions of clade names suffer from similar problems and we argue that clade names cannot be defined since they lack intension. Furthermore we stress the importance of “tree-thinking” for phylogenetic reference to work properly.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006583910214
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  • 44
    Digitale Medien
    Digitale Medien
    On the Relationship Between Memes and Genes: A Critique of Dennett (1998)
    Springer
    Biology and philosophy 13 (1998), S. 187-204 
    Details
    ISSN: 1572-8404
    Schlagwort(e): evolution ; meme ; gene ; morality ; culture ; psychological predisposition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Abstract Dennett (1995) argues that memes or cultural replicators are largely autonomous of genes, and that they are fairly efficacious in determining who we are and what we do. I argue that Dennett's arguments are wrong in several aspects, which we can see by analyzing processes at appropriate levels. Specifically, I argue that it is not true that we as persons are created largely by memes, that our memes are not largely independent of our genes, and that we can use the universality of memes to make inferences about genetic predispositions. Finally, by suggesting an innate psychological mechanism for morality, I argue that morality may be largely the effect of genetic predispositions rather than autonomous.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006529312488
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  • 45
    Digitale Medien
    Digitale Medien
    The Tragedy of a priori Selectionism: Dennett and Gould on Adaptationism (1998)
    Springer
    Biology and philosophy 13 (1998), S. 359-391 
    Details
    ISSN: 1572-8404
    Schlagwort(e): adaptation ; algorithm ; atavism ; contingency ; deep homology ; Dennett ; development ; disparity ; epicurean selectionism ; evolution ; exaptation ; Gould ; metaphors ; punctuated equilibrium ; selectionism ; spandrels
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Abstract In his recent book on Darwinism, Daniel Dennett has offered up a species of a priori selectionism that he calls algorithmic. He used this view to challenge a number of positions advocated by Stephen J. Gould. I examine his algorithmic conception, review his unqualified enthusiasm for the a priori selectionist position, challenge Dennett's main metaphors (cranes vs. skyhooks and a design space), examine ways in which his position has lead him to misunderstand or misrepresent Gould (spandrels, exaptation, punctuated equilibrium, contingency and disparity), and discuss recent results in developmental biology that suggest that an a priori position does not fill the demands of an evolutionary biology. I conclude by insisting that evolutionary biology is many leveled, complicated, and is carried on an ever shifting and expanding empirical base that when disregarded results in caricature.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006508719300
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  • 46
    Digitale Medien
    Digitale Medien
    On the Spectral Decomposition of Geopotential and Temperature Fields in the Stratosphere (1998)
    Springer
    Studia geophysica et geodaetica 42 (1998), S. 147-158 
    Details
    ISSN: 1573-1626
    Schlagwort(e): stratosphere ; spectral decomposition ; geopotential ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geologie und Paläontologie , Physik
    Notizen: Abstract The spectral structure of stratospheric fields (temperature and geopotential) is analyzed in terms of spherical harmonics in an effort to study the long-term behaviour of large-scale circulation patterns, as well as their connections to some extra-terrestrial effects. The daily meteorological data from the Free University Berlin (FUB) cover more or less the period 1976–1996 and are available for stratospheric levels of 50, 30 and 10 hPa. The analysis of the annual cycle of spherical harmonics is introduced, and changes of the principal wave components are compared with the changes in different sets of solar, geomagnetic and global circulation indices. This paper also deals with interannual variability with special emphasis on quasibiennial oscillations (QBO) and El Nino and Southern Oscillations (ENSO). Although this is a rather preliminary study, the decomposition of the stratospheric field into complex spherical harmonics seems to be a powerful technique in investigating and qualifying the response of the global atmospheric system to the changes in solar and geomagnetic activity, and in qualifying the relationships between large-scale circulation patterns and various oscillations such as QBO or ENSO, Using this technique, reasonable strong connections were found between wave numbers and interannual factors, and these connections were tentatively interpreted in terms of statistics. A very high degree of correlation was found for the four-trough shape of the polar vortex.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1023305020573
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  • 47
    Digitale Medien
    Digitale Medien
    Changes of Ozone Content at Middle Latitudes During Forbush Decreases in Cosmic Rays (1998)
    Springer
    Studia geophysica et geodaetica 42 (1998), S. 521-532 
    Details
    ISSN: 1573-1626
    Schlagwort(e): stratospere ; troposphere ; solar-terrestrial disturbances ; odd nitrogen ; temperature ; atmospheric dynamics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geologie und Paläontologie , Physik
    Notizen: Abstract The variations of total ozone at Alma-Ata (43°N, 76 °E) and ozone profiles obtained by balloon sounding at Tateno (36°N, 140°E), Wallops Island (38°N, 75°W) and Cagliari (39°N, 9°E) in the periods of Forbush decreases (FD) in galactic cosmic rays have been analysed. A decrease of total ozone was observed in the initial stage of the FD and an increase 10–11 days later. The average total deviations calculated using the superposed epoch method for 9 FD events are equal to 30 D. U. in the positive and to −18 D. U. in the negative phase. The changes of average ozone profiles, associated with 26 FD events, are more significant in the lower stratosphere and upper troposphere. The decrease of the partial ozone pressure at a height of 12–15 km is about 30 υmb. These vertical variations of ozone coincide with the average changes of the respective temperature profiles. A cooling, on the average, of 3°C was observed at 12–15 km, and a heating of 4°C below this level.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1023301322428
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  • 48
    Digitale Medien
    Digitale Medien
    Influence of temperature and nitrogen concentration on photosynthesis ofDunaliella viridis Teodoresco (1990)
    Springer
    Journal of applied phycology 2 (1990), S. 309-317 
    Details
    ISSN: 1573-5176
    Schlagwort(e): Dunaliella viridis ; net photosynthesis ; temperature ; nitrogen concentration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The photosynthetic behaviour ofDunaliella viridis has been studied under a combination of three variables: irradiance (0–900 μmol m−2 s−1), temperature (15, 23, 31, 38, 42 °C) and nitrogen concentration (0.05, 0.5, 1.5, 5, 10 mM NO 3 - ) at a salinity of 2 M NaCl. The highest rates of photosynthesis have been found at 31 °C and a nitrate concentration of 10 mM. There exists a synergistic effect between temperature and nitrogen availability on the photosynthesis ofD. viridis; under nitrogen deficiency oxygen evolution is low, even null at high temperature. The interaction between these two variables of control occurs in a multiplicative way. There is also a general increase in photosynthetic pigments following the increase in nitrogen concentration in the culture medium. The normalization of net photosynthesis data in relation to chlorophylla shows that nitrogen concentration makes an indirect control of the photosynthetic rate ofD. viridis through the variation of pigment concentration. The study of the photosynthetic parameters shows that the slope (α) of the curves of photosynthesis and the light-saturated photosynthesis (Pmax) are controlled by more than one variable, including temperature and nitrogen availability.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02180920
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  • 49
    Digitale Medien
    Digitale Medien
    Effects of environmental parameters on net photosynthesis of a free-living brown seaweed,Cystoseira barbata formarepens: determination of optimal photosynthetic culture conditions (1990)
    Springer
    Journal of applied phycology 2 (1990), S. 281-287 
    Details
    ISSN: 1573-5176
    Schlagwort(e): Cystoseira barbata ; photosynthesis ; light ; temperature ; salinity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The net photosynthesis of the Mediterranean brown seaweedCystoseira barbata f.repens is measured according to irradiance, temperature and salinity. There is not only, a good utilization of low light intensities (light-shade adaptation), but also a specific ability to use a broad range of irradiance, which corresponds in the photosynthesis-irradiance curves to a high initial slope and an extended light saturation level from 300 to 1500 μmol photon m−2 s−1; only very high irradiances induce photoinhibition. Maximum net photosynthesis occurred at temperatures ranging from 20 °C to 30 °C. The alga tolerates not only a low level of salinity, but also a slight increase in salinity; however, at more than 47.5 g 1−1 NaCl, oxygen exchange is significantly reduced. Light, temperature and salinity requirements are discussed, taking into account ecological considerations. Yields and quality of alginic acid are presented according to the irradiance and yearly evolutionin situ in order to aid future cultivation of this species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02179786
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  • 50
    Digitale Medien
    Digitale Medien
    High temperature conjugation of proteins with carbohydrates (1998)
    Springer
    Glycoconjugate journal 15 (1998), S. 131-138 
    Details
    ISSN: 1573-4986
    Schlagwort(e): protein ; conjugate ; carbohydrate ; lyophilization ; vaccine ; temperature ; heating
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A new procedure was used to conjugate lactose and dextran with BSA without using coupling or activating reagents. The method is simple, rapid and cheap. Reducing sugars covalently bind to proteins when lyophilized together and briefly heated to a high temperature.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007067513242
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  • 51
    Digitale Medien
    Digitale Medien
    Speciation of endemic Lake Tana barbs (Cyprinidae, Ethiopia) driven by trophic resource partitioning; a molecular and ecomorphological approach (1998)
    Springer
    Aquatic ecology 32 (1998), S. 217-227 
    Details
    ISSN: 1573-5125
    Schlagwort(e): ecomorphology ; evolution ; feeding ; fish stocks ; major histocompatibility complex ; molecular genetics ; species flock
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A unique species flock of large barbs (Barbus spp.) from Lake Tana is presented, from the level of fish stocks to molecules. Evidence is given for the species status of 14 morphotypes of large barbs. They distinctly differ in: (1) head and body morphometrics, (2) food preferences, (3) distribution patterns, (4) maximal body size, (5) spawning area and period, and (6) molecular genetic characters. Most types show early morphological divergence at small size. Major Histocompatibility Complex (MHC) genes, encoding cell membrane proteins involved in defence against pathogens, were found to be diagnostic for the species' genetic identity. A strong selective pressure on particular amino acid positions in the MHC protein sequence most probably arose in response to different pathogen loads from the newly invaded ecological niches after formation of Lake Tana, ca. two million years ago. Arguments for a sympatric origin of this species flock are discussed. An evolutionary scenario suggests a riverine ancestral Barbus intermedius invading Lake Tana after its formation by volcanic blocking of the Blue Nile river and its isolation by waterfalls. Specialisation for particular food types and disruptive selection on many feeding structures are hypothesized as the evolutionary drive in speciation. The causal relationship between the diversity in feeding structures and food types is explained from experiments and models. As an example, the potential food niche of three barb species is predicted from parameter values measured from a large set of feeding structures and tested against the actual gut contents. The co-occurrence of eight piscivorous barb species is unique for cyprinid fish, which lack oral jaw teeth and a stomach. The significance of this aquatic ecosystem as a multidisciplinary evolutionary laboratory and the need for a wise balance between exploitation and conservation is stressed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009920522235
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  • 52
    Digitale Medien
    Digitale Medien
    Effect of streptozocin on temperature variations in rats (1990)
    Springer
    Bulletin of experimental biology and medicine 110 (1990), S. 1330-1333 
    Details
    ISSN: 1573-8221
    Schlagwort(e): streptozocin ; temperature ; diabetes mellitus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00842276
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  • 53
    Digitale Medien
    Digitale Medien
    The species censorship problem: A general solution (1990)
    Springer
    Mathematical geology 22 (1990), S. 95-106 
    Details
    ISSN: 1573-8868
    Schlagwort(e): evolution ; extinction ; macroevolution ; probability ; species longevity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract The longevities of species constituting a statistical population have an underlying distribution whose form and parametric values reflect probabilities of origination and extinction through time. In the case that a part of the population is extant, the form of distribution and its parameters cannot be estimated directly from the longevity data without bias. Longevities of extant “censored” species are truncated and thus do not statistically represent the underlying distribution. The remaining “uncensored” species do not represent the true relative abundances of longevities. These biases can be defined from the probability densities for species longevitys and intervalr between successive originations of species. For realistic densities ofs andr, species with an intermediate longevity are preferentially censored. This simple, general result arises because the probability of censoring a species increases with its longevity, whereas the probability of censoring a given longevity varies with its relative abundance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00890299
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  • 54
    Digitale Medien
    Digitale Medien
    Amalthaea: An Evolving Multi-Agent Information Filtering and Discovery System for the WWW (1998)
    Springer
    Autonomous agents and multi-agent systems 1 (1998), S. 59-88 
    Details
    ISSN: 1573-7454
    Schlagwort(e): agents ; evolution ; information filtering ; world wide web
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract Amalthaea is an evolving, multi-agent ecosystem for personalized filtering, discovery, and monitoring of information sites. Amalthaea's primary application domain is the World Wide Web and its main purpose is to assist its users in finding interesting information. Two different categories of agents are introduced in the system: filtering agents that model and monitor the interests of the user and discovery agents that model the information sources.A market-like ecosystem where the agents evolve, compete, and collaborate is presented: agents that are useful to the user or other agents reproduce, while low-performing agents are destroyed. Results from various experiments with different system configurations and varying ratios of user interests versus agents in the system are presented. Finally issues like fine-tuning the initial parameters of the system and establishing and maintaining equilibria in the ecosystem are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010094506174
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  • 55
    Digitale Medien
    Digitale Medien
    Heat Transfer in Nonsaturated Porous Media. Modelling by Homogenisation (1998)
    Springer
    Transport in porous media 30 (1998), S. 301-321 
    Details
    ISSN: 1573-1634
    Schlagwort(e): temperature ; homogenisation ; modelling ; unsaturated
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Technik allgemein
    Notizen: Abstract This paper is devoted to the modelling of a temperature field in nonsaturated porous media in the absence of phase change. We establish the energy equation at the macroscopic level, from a description at the pore level by using the homogenisation method of multiple-scale asymptotic expansions. Different macroscopic models are obtained depending on the values of the local Péclet number and the local Fourier number. An example of the application of the different model catalogue is presented which concerns the modelling of the hot pressing of a paper web.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006540912415
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  • 56
    Digitale Medien
    Digitale Medien
    The phytoplankton succession in the lower part of hypertrophic Nakdong River (Mulgum), South Korea (1998)
    Springer
    Hydrobiologia 369-370 (1998), S. 217-227 
    Details
    ISSN: 1573-5117
    Schlagwort(e): regulated river ; Microcystis bloom ; discharge ; temperature ; community composition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Investigations were carried out to determine the mechanism of phytoplankton succession in the lower part of Nakdong River. Intensive monitoring was conducted from April 1993 to April 1995 at weekly or biweekly intervals. This river is the main source of drinking water for more than 8 million residents living in Pusan and the Southeastern region of Korea, and it is also important for industrial purposes. Due to the rapid urbanization and industrialization, this river has become hypertrophic and it is heavily regulated (mean chl. a, 79±232 µg l-1 n = 76; mean TN, 4.3±2.0 mg l-1 n=30; mean TP, 165 ± 108 µg l-1 n = 45). Bacillariophyceae were dominant year-round in 1993, with spring and late fall peaks. Dominant communities in 1994 were Bacillariophyceae in March and April, Chlorophyceae and Cryptophyceae in May, Cyanobacteria in July and August, Chlorophyceae and Cryptophyceae in October, and Bacillariophyceae in December. As drought persisted through the summer of 1994, elevated water temperature (over 30 °C) possibly triggered Cyanobacteria bloom (mainly Microcystis aeruginosa, maximum cell density, 1.6 × 107 cells ml-1). The most common diatom, Stephanodiscus hantzschii, repeatedly dominated from late fall to next spring (mean and maximum cell density, 7.5 × 104, 1.2 × 105 cells ml-1, respectively). This small centric diatom was favored by the low discharge and the cold water (water temperature, 3–10 °C). After the diatom bloom, this community shifted to peaks of colonial Chlorophyceae and motile Cryptophyceae, owing to the high rate of zooplankton grazing activity and increased water temperature. Overall, the phytoplankton periodicity was primarily governed by the hydrologic regime (discharge). Changes in silica concentration, water temperature and high zooplankton density might have played an important role in phytoplankton dynamics during the non-flooding periods. Compared to other large rivers, strong Microcystis bloom events in summer and Stephanodiscus bloom events in winter were noticeable in the dry year. The patterns of phytoplankton succession observed in this study may have a significance since most of the large rivers in Far Eastern Asian countries are subjected to eutrophication and regulation of discharge.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017067809089
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  • 57
    Digitale Medien
    Digitale Medien
    Heat-induced testicular apoptosis occurs independently of hormonal depletion (1998)
    Springer
    Apoptosis 3 (1998), S. 281-288 
    Details
    ISSN: 1573-675X
    Schlagwort(e): Androgen ; apoptosis ; heat stress ; hormone ; temperature ; testis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Previous studies have demonstrated that testicular germ cell apoptosis can be induced both by heat stress and by withdrawal of androgens and gonadotrophins. To investigate whether heat-induced germ cell apoptosis occurs independently of the altered levels of hormones that occur with heat exposure, mouse testicular apoptosis was studied using an in vitro system with controlled levels of testosterone, FSH and LH. It was observed that cells underwent apoptosis sooner in the absence of hormones at the same temperature. Apoptosis also occurred earlier at abdominal temperature compared to scrotal temperature with the same hormonal levels. No somatic tissues studied underwent apoptosis at 37°C under the same culture conditions. These results suggest that heat stress may independently activate an apoptotic pathway in the testis, and that hormone deprivation may induce apoptosis via a separate mechanism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009665309915
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  • 58
    Digitale Medien
    Digitale Medien
    Complete sequence of the mitochondrial DNA of Chlamydomonas eugametos (1998)
    Springer
    Plant molecular biology 36 (1998), S. 285-295 
    Details
    ISSN: 1573-5028
    Schlagwort(e): Chlamydomonas eugametos ; evolution ; genome sequence ; green algae ; group I introns ; mitochondrial DNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The complete nucleotide sequence of the Chlamydomonas eugametos (Chlamydomonadales, Chlorophyceae, sensu Mattox and Stewart) mitochondrial genome has been determined (22 897 bp, 34.6% G + C). The genes identified in this circular-mapping genome include those for apocytochrome b, subunit 1 of the cytochrome oxidase complex, subunits 1, 2, 4, 5, and 6 of the NADH dehydrogenase complex, discontinuous large and small subunit ribosomal rRNAs and three tRNAs whose anticodons CAU, CCA and UUG are specific for methionine, tryptophan and glutamine, respectively. The C. eugametos mitochondrial DNA (mtDNA), therefore, shares almost the same reduced set of coding functions and similar unusual features of rRNA gene organization with the linear 15.8 kb mtDNA of Chlamydomonas reinhardtii, the only other completely sequenced chlamydomonadalean mtDNA. However, sequence analysis of the C. eugametos mtDNA has revealed the following distinguishing features relative to those of C. reinhardtii: (1) the absence of a reverse transcriptase-like gene homologue, (2) the presence of an additional gene for tRNAmet that may be a pseudogene, (3) a completely different gene order, (4) transcription of all genes from the same mtDNA strand, (5) a lower G + C content, (6) less pronounced bias in codon usage, and (7) nine group I introns, several of which contain open reading frames coding for potential maturases/endonucleases and two have a nucleotide at the 5′ or 3′ splice site of the deduced precursor RNAs that deviates from highly conserved nucleotides reported in other group I introns. The features of mitochondrial genome organization and gene content shared by C. eugametos and C. reinhardtii contrast with those of other green algal mtDNAs that have been characterized in detail. The deep evolutionary divergence between these two Chlamydomonas taxa within the Chlamydomonadales suggests that their shared features of mitochondrial genome organization evolved prior to the origin of this group.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1005995718091
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  • 59
    Digitale Medien
    Digitale Medien
    Anatomic and metabolic responses to thermal acclimation in the ninespine stickleback, Pungitius pungitius (1990)
    Springer
    Fish physiology and biochemistry 8 (1990), S. 465-473 
    Details
    ISSN: 1573-5168
    Schlagwort(e): temperature ; acclimation ; acclimatization ; muscle ; metabolic organization ; sticklebacks
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Male ninespine sticklebacks, Pungitius pungitius, acclimated to 3°C have higher activities of mitochondrial enzymes in their axial muscles than males acclimated to 20°C. Phosphofructokinase and pyruvate kinase activities tended to be higher in cold than warm acclimated males. For females, warm acclimation tended to decrease only mitochondrial enzyme activities. As thermal acclimation did not change the physical condition and most anatomic parameters of the sticklebacks, the enzymatic changes do not seem due to mobilization of somatic reserves. Field acclimatization to warm temperatures led to a marked decrease in physical condition in both males and females. This decrease in physical condition could largely be attributed to atrophy of the carcass mass. Spring males had higher activities of phosphofructokinase, citrate synthase and cytochrome oxidase in the axial muscle than summer males. Again, females showed a less marked response. These data suggest that environmental temperature is a major determinant of muscle aerobic capacity, at least for male ninespine sticklebacks. Thus, these northern temperate zone fish retain the capacity for thermal compensation, much like their temperate zone counterparts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00003403
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  • 60
    Digitale Medien
    Digitale Medien
    Interactive effects of elevated carbon dioxide and growth temperature on photosynthesis in cotton leaves (1998)
    Springer
    Plant growth regulation 26 (1998), S. 33-40 
    Details
    ISSN: 1573-5087
    Schlagwort(e): carbohydrates ; elevated CO2 ; Gossypium hirsutum L. ; interaction ; photosynthesis ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Cotton (Gossypium hirsutum L., cv DPL 5415) plants were grown in naturally lit environment chambers at day/night temperature regimes of 26/18 (T-26/18), 31/23 (T-31/23) and 36/28 °C (T-36/28) and CO2 concentrations of 350 (C-350), 450 (C-450) and 700 μL L-1 (C-700). Net photosynthesis rates, stomatal conductance, transpiration, RuBP carboxylase activity and the foliar contents of starch and sucrose were measured during different growth stages. Net CO2 assimilation rates increased with increasing CO2 and temperature regimes. The enhancement of photosynthesis was from 24 μmol CO2 m-2 s-1 (with C-350 and T-26/18) to 41 μmol m-2 s-1 (with C-700 and T-36/28). Stomatal conductance decreased with increasing CO2 while it increased up to T-31/23 and then declined. The interactive effects of CO2 and temperature resulted in a 30% decrease in transpiration. Although the leaves grown in elevated CO2 had high starch and sucrose concentrations, their content decreased with increasing temperature. Increasing temperature from T-26/18 to 36/28 increased RuBP carboxylase activity in the order of 121, 172 and 190 μmol mg-1 chl h-1 at C-350, C-450 and C-700 respectively. Our data suggest that leaf photosynthesis in cotton benefited more from CO_2 enrichment at warm temperatures than at low growth temperature regimes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006035517185
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  • 61
    Digitale Medien
    Digitale Medien
    Phagotrophy by a flagellate selects for colonial prey: A possible origin of multicellularity (1998)
    Springer
    Evolutionary ecology 12 (1998), S. 153-164 
    Details
    ISSN: 1573-8477
    Schlagwort(e): algae ; anti-predator adaptations ; arms race ; Chlorella vulgaris ; chrysophytes ; continuous culture ; evolution ; flagellates ; multicellularity ; Ochromonas vallescia ; phagocyte ; predator–prey interactions ; selective pressure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Predation was a powerful selective force promoting increased morphological complexity in a unicellular prey held in constant environmental conditions. The green alga, Chlorella vulgaris, is a well-studied eukaryote, which has retained its normal unicellular form in cultures in our laboratories for thousands of generations. For the experiments reported here, steady-state unicellular C. vulgaris continuous cultures were inoculated with the predator Ochromonas vallescia, a phagotrophic flagellated protist (‘flagellate’). Within less than 100 generations of the prey, a multicellular Chlorella growth form became dominant in the culture (subsequently repeated in other cultures). The prey Chlorella first formed globose clusters of tens to hundreds of cells. After about 10–20 generations in the presence of the phagotroph, eight-celled colonies predominated. These colonies retained the eight-celled form indefinitely in continuous culture and when plated onto agar. These self-replicating, stable colonies were virtually immune to predation by the flagellate, but small enough that each Chlorella cell was exposed directly to the nutrient medium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006527528063
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  • 62
    Digitale Medien
    Digitale Medien
    Nest-site philopatry and selection for environmental sex determination (1998)
    Springer
    Evolutionary ecology 12 (1998), S. 245-250 
    Details
    ISSN: 1573-8477
    Schlagwort(e): environmental sex determination ; evolution ; nest-site philopatry ; reptiles ; sex ratio
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The reason for the frequent occurrence of environmental sex determination (ESD) in reptiles is still not well understood, although much effort has been devoted to solving the issue. Stimulated by the occurrence of nest-site philopatry in some species, this paper examines a diploid model of the influence of nest-site philopatry on the evolution of ESD. Analysis shows that nest-site philopatry can lead to ESD because the fitnesses of sons and daughters are not influenced in the same way by nest-site quality. Daughters inherit the nest site and thus benefit more than sons from a high-quality nest site. Conversely, the fitness of daughters at low-quality nest sites is lower compared to the fitness of sons. Therefore, genes causing ESD can spread by causing the production of more sons at low-quality nest sites and more daughters at high-quality nest sites. Suggestions are made to test empirically whether nest-site philopatry led to the evolution of ESD.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006591914859
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  • 63
    Digitale Medien
    Digitale Medien
    Integrated Pharmacokinetic–Pharmacodynamic Model for Acetaminophen, Ibuprofen, and Placebo Antipyresis in Children (1998)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 26 (1998), S. 559-579 
    Details
    ISSN: 1573-8744
    Schlagwort(e): acetaminophen ; age ; antipyretic ; fever ; ibuprofen ; pediatrics ; pharmacokinetics ; pharmacodynamics ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A descriptive profile for antipyretic drug action has been documented for children. However, a linked pharmacokinetic–pharmacodynamic (PK/PD) model is central to the understanding of antipyretic drug action in febrile children. This was examined for previously reported data from 178 febrile children who received a single oral dose of acetaminophen (APAP) (12.5 mg/kg), ibuprofen (IBU) (5 or 10 mg/kg), or placebo. Rectal temperatures and plasma levels (μg/ml) of APAP and IBU were measured for up to 12 hr after drug administration. Nonlinear regression analyses were applied to these measurements and yielded simultaneous solutions of an integrated one-compartment PK, link, and SigmoidEmax effect model in 102/153 febrile children given APAP or IBU. The PK parameters (tlag ,ka , β,T1 / 2β ,AUC0–∞ ,Vd/F,andClp/F) were not different than those reported previously, except the APAPka was significantly lower. The link component yieldedkeo s of 0.58±0.06 (X±SE), 0.70±0.11 and 0.57 ± 0.11 hr -1 for APAP, IBU05, and IBU10, respectively: the SigmoidEmax component yieldedEC50 s (μg/ml) and sigmoidicity (γ) of 4.63±0.39 and 3.98±0.42 for APAP, 11.33±1.35 and 3.97±0.58 for IBU05 and 12.83±1.89 and 4.27±0.63 for IBU10. On visual inspection of the efficacy–time profiles of the febrile children, a number of them had an apparent linear function (slope; Δ°C/hr) and/or a sinusoidal cyclic function “confounding” standard approaches to PD analysis. Thus, the temperature profiles of 91/102 children given APAP or IBU required the addition of a slope (Δ°C/hr) and/or a sinusoidal cyclic function to the SigmoidEmax component to fit the data satisfactorily. All 22 children given a placebo also required a slope and/or a cyclic function in their PD model. The residual Δ°Cs (observed-predicted) of the placebo group were not significantly different from 0. Thus, no placebo antipyretic effect was observed. Dose dependency of IBUAUC0–∞ was confirmed; doubling the dose from 5 to 10 mg/kg increased theAUC0→∞ by only 1.5-fold. The confounding effect of initial temperature (Tempi ) on antipyretic efficacy in all treatment groups except placebo was also confirmed to expose nonlinear pharmacodynamics. A significant (p=0.03) contribution ofTempi (but not age) on the value of the slope function was found. There was no consistent effect of age orTempi , on the cyclic component of the integrated model of antipyresis. In addition, a multiple linear relationship of age andTempi was observed with a large number of the PK, link, and PD variables in those who received IBU. Dose, age, andTempi interacted with β in a significant multiple linear relationship withAUC0–∞ . The effects of IBU dose, age, andTempi are pervasive and cascade down the chain of events leading to the PD response. The etiology of pyresis may create the slope function, the magnitude of which may be partially due to the underlying disease. In some cases, the cyclic function may be explained by temperature regulation. Regardless of their cause, both confound analysis of drug action and make the simple, unmodified SigmoidEMax effect model less than satisfactory for interpretation of antipyretic drug effects. The influence of Tempi on the magnitude of antipyretic drug response is also a finding with major impact on PD investigations of antipyretic medications. In children receiving IBU, dose and age are also confounders, in addition toTempi . A multiplicity of covariables must be taken into account when developing appropriate dosing regimens for these antipyretics in febrile children.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1023225217108
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  • 64
    Digitale Medien
    Digitale Medien
    The cytotaxonomy ofEmilia spp. (Asteraceae: Senecioneae) occurring in Brazil (1990)
    Springer
    Plant systematics and evolution 170 (1990), S. 229-236 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Asteraceae ; Emilia ; Chromosome numbers ; C-banding ; cytogeography ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Analysis of several populations in a large part of the distribution area of the genusEmilia in Brazil has revealed only two species: the diploidE. sonchifolia and the tetraploidE. fosbergii. The more widely reportedE. coccinea was not found. They show a karyotype constancy in morphology and chromosome number (2n = 10 and 2n = 20, respectively), C-banding pattern and number of secondary constrictions. Some indications were found thatE. fosbergii may be an allopolyploid and that its ancestors had different genome sizes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00937706
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  • 65
    Digitale Medien
    Digitale Medien
    Systematics and evolution within theCompositae, seen with the eyes of a chemist (1990)
    Springer
    Plant systematics and evolution 171 (1990), S. 1-14 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Compositae ; Chemistry ; systematics ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The broad knowledge of the chemistry of theCompositae allows the discussion of its relevance for the systematics and evolution within the family. Furthermore a separation into subfamilies can be supported by the observed differences in the distribution of the main constituents in the tribes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00940593
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  • 66
    Digitale Medien
    Digitale Medien
    Ecogeographical differentiation patterns inAdonis sect.Consiligo (Ranunculaceae) (1998)
    Springer
    Plant systematics and evolution 211 (1998), S. 43-56 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Ranunculaceae ; Adonis ; Morphology ; growth pattern ; taxonomy ; ecology ; climatic requirements ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Adonis sect.Consiligo is split into three subsections based on morphology, growth pattern, pollen and fruit morphology. For all species distribution maps are provided and discussed with regard to their ecology and climatic requirements. These data reveal additional characters that support the classification of the taxa. Most species of the section grow in continental Eurasiatic steppes and mountain steppe habitats. Only the species of subsect.Amurenses grow in Far Eastern temperate forests and prefer a more oceanic climate. The taxonomic position of these strongly divergent species is supported by the distributional and ecological data. The evolution ofAdonis sect.Consiligo occurred under strong climatic control. During evolution the taxa could only slightly widen their ecological amplitude and, thus, ecology remained rather stable except that of the subsect.Amurenses. Ecological and distributional data can be used to validate taxonomy and phylogeny and reveal additional informations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00984911
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  • 67
    Digitale Medien
    Digitale Medien
    Genome size variation and C-band polymorphism inAlstroemeria aurea, A. ligtu andA. magnifica (Alstroemeriaceae) (1998)
    Springer
    Plant systematics and evolution 212 (1998), S. 87-106 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Alstroemeriaceae ; Alstroemeria aurea ; A. ligtu ; A. magnifica ; C-band polymorphism ; evolution ; flow cytometry ; genome size
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Among a total of 43 accessions ofAlstroemeria aurea, A. ligtu andA. magnifica nuclear DNA amounts (2C-values) showed significant intraspecific variation, 1.09, 1.21 and 1.15 fold, respectively, when determined through flow cytometric measurements of fluorescence of propidium iodide (PI) stained nuclei. After staining with another fluorochrome, 4′,6-diamidino-2-phenylindole (DAPI), an intraspecific variation of 1.10, 1.11 and 1.12 fold, respectively, was found. C-band polymorphisms were present among and within the accessions of all three species. In some cases only very small differences in C-banding pattern were observed. In other cases, however, differences were more prominent. Besides C-band polymorphism, there were also instances of chromosome length polymorphism, which concerned the total chromosome complement or single chromosomes. The variation in nuclear DNA amount inA. aurea andA. ligtu was more or less continuous, except for one accession ofA. ligtu subsp.simsii. Artificial selection and possibly introgression of chromosomes from other species may have moulded the karyotypes of some of the accessions ofA. aurea, a species that has been under cultivation for more than 160 years. The variation as observed inA. magnifica subsp.magnifica was discontinuous and could be due to a broad species concept.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00985223
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  • 68
    Digitale Medien
    Digitale Medien
    Sympodial and monopodial branching inAcer (Aceraceae): Evolutionary trend and ecological implications (1990)
    Springer
    Plant systematics and evolution 171 (1990), S. 187-197 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Aceraceae ; Acer ; Sympodial and monopodial branching ; evolution ; adaptive strategy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The evolutionary trend and its ecological implications in sympodial and monopodial branching patterns has been investigated in 20 JapaneseAcer spp. through comparison of shoot tip abortion and terminal bud formation. The genus is divided into two species groups according to its branching pattern, one (6 species) predominantly exhibiting sympodial branching with frequent monopodial branching in short shoots (sympodial species), and the other (14 species) exhibiting only monopodial branching (monopodial species). The early ontogeny of leaf and bud scales is described. Despite the difference in branching patterns, the bud scales of terminal buds are essentially the same in having a leaf base developed to function as a protecting organ. In all the sympodial species, during the abortion of a sympodium shoot tip, one or two pairs of primordia were found to occur on the apex, and later wither. These primordia resemble bud scales of terminal buds in their ontogeny and morphology, and appear to be rudimentary. It is suggested that a rudimentary terminal bud develops together with the establishment of sympodial branching, and that sympodial branching has originated from monopodial branching. Based on this proposed evolutionary trend, it is suggested thatAcer has moved from less shady habitats into shady habitats with monopodial branching (advantageous for vertical growth) changing into sympodial branching (advantageous for lateral spread).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00940604
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  • 69
    Digitale Medien
    Digitale Medien
    Genetic divergence and introgressive hybridization betweenAlnus sinuata andA. crispa (Betulaceae) (1990)
    Springer
    Plant systematics and evolution 170 (1990), S. 107-124 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Betulaceae ; Alnus ; Isozymes ; population genetics ; hybridization ; genetic distance ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The actinorhizal genusAlnus contains numerous taxa that have been morphologically classified into different subgenera, species and subspecies. The genetic divergence has been evaluated within subg.Alnobetula between the parapatric taxaAlnus sinuata andA. crispa, using diversity of allozyme markers at 15 structural loci among 20 populations. Evidence for introgressive hybridization at the overlap of their ranges was noted in three populations. However, the width of the hybrid zone appeared tenuous. The average genetic distance derived from the comparisons of conspecific populations was much smaller than the interspecific distance (D = 0.047). This allelic divergence was also paralleled with larger amounts of allelic and genotypic diversity within and among populations ofA. sinuata, which are occupying a more heterogenous ecological niche. It is proposed that the repeated advances and retreats of the ice sheet during the Pleistocene may have promoted the divergence and allopatric evolution of these subspecies, and that secondary contact may have occurred repeatedly during the interglacial periods. The dynamic-equilibrium model would predict in such cases that narrow hybrid zones, formed at the contact of parapatric ranges, would impede gene exchange between parental taxa by selection against hybrids. The results obtained in this study seemed concordant with this hypothesis, as they were also in agreement with the existent taxonomical treatment of these taxa based on morphology.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00937853
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  • 70
    Digitale Medien
    Digitale Medien
    A phylogenetic analysis of chloroplast DNA restriction site variation inPoaceae subfam.Pooideae (1990)
    Springer
    Plant systematics and evolution 172 (1990), S. 83-97 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Poaceae ; Pooideae ; Phylogenetics ; evolution ; chloroplast DNA ; restriction site variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A phylogenetic analysis was conducted on chloroplast DNA restriction site variation in 34 genera of grasses (familyPoaceae), including 28 genera from subfam.Pooideae (representing tribesAveneae, Brachypodieae, Bromeae, Meliceae, Poeae, Stipeae, andTriticeae) and representatives of three other subfamilies,Arundinoideae, Oryzoideae, andPanicoideae. Analyses of all 34 genera always distinguishedPooideae as monophyletic, regardless of which nonpooid genus functioned as outgroup; six separate analyses of all 28 pooid genera, each including one of the six nonpooid genera as outgroup, resolved five identically-constituted clades withinPooideae (in four cases), or (in the other two cases) yielded results that were less well resolved, but not in conflict with those of the other four analyses. The four best-resolved analyses distinguishedMeliceae as the earliest diverging lineage withinPooideae, andStipeae as the next. Above the point of divergence ofStipeae is a dichotomy between supertribeTriticodae (including tribesBrachypodieae, Bromeae, andTriticeae), and a clade comprisingPoeae andAveneae. The analysis supports some tribal realignments, specifically the assignment ofBriza, Chascolytrum, Microbriza, andTorreyochloa toAveneae, andArctagrostis, Catabrosa, andSesleria toPoeae. The analysis also suggests that the pooid spikelet (i.e., glumes shorter than lemmas and florets two or more) is plesiomorphic inPooideae, and that spikelets with one floret, and those with glumes longer than the first lemma, each have evolved more than once withinPooideae. Results also indicate that small chromosomes and chromosome numbers based on x=c. 10−12 are plesiomorphic withinPooideae. Alternative states of these characters (chromosomes large, chromosome numbers based on x=7) are interpreted as synapomorphies or parallelisms of clades that includeTriticodae, Aveneae, andPoeae. Lanceolate lodicule shape may be a synapomorphy of the clade that includesStipeae, Triticodae, Aveneae, andPoeae, and loss of lodicule vascularization a synapomorphy of the entirePooideae.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00937800
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  • 71
    Digitale Medien
    Digitale Medien
    Evolution of the tetraploidCapsella bursa-pastoris (Brassicaceae): Isoelectric focusing analysis of Rubisco (1990)
    Springer
    Plant systematics and evolution 172 (1990), S. 205-213 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Brassicaceae ; Capsella ; Ribulose-1,5-bisphosphate carboxylase/oxygenase ; isoelectric focusing ; evolution ; polyploidization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1.39) and its subunits (large subunits = LSU, small subunits = SSU) were isolated from threeCapsella spp. by gel electrophoresis and polypeptide composition was analyzed by isoelectric focusing (IEF) in the presence of 8M urea. The described techniques are recommended for large scale systematic studies. Multiple IEF banding patterns of the SSU are probably the outcome of a heterogenous multigene family. The two diploid speciesC. rubella andC. grandiflora show an identical IEF pattern and could be differentiated from the putative allotetraploidC. bursa-pastoris only by the SSU banding pattern. Uniqueness of some SSU bands in the tetraploid and in the two diploid species, respectively, may indicate an ancient alloploid origin of tetraploidC. bursa-pastoris followed by events leading to divergences in the genomes of the allotetraploid and its presumed diploid progenitors after the hybridization event (SSU gene elimination, acquisition of new SSU genes).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00937807
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  • 72
    Digitale Medien
    Digitale Medien
    The behaviour of the autonomous maize transposable element En/Spm in Arabidopsis thaliana allows efficient mutagenesis (1998)
    Springer
    Plant molecular biology 37 (1998), S. 989-999 
    Details
    ISSN: 1573-5028
    Schlagwort(e): Arabidopsis thaliana ; transposable element ; En-1 ; mutagenesis ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The behavior of the autonomous maize transposable element En/Spm of maize was studied in Arabidopsis. Transgenic Arabidopsis plants carrying En-1 elements were propagated for 12 generations using a single seed descent procedure. The distribution and activity of the En-1 element was monitored using Southern DNA hybridisations in generations 1, 6 and 12. In the first generation the highest number of En-1 insertions per line was 7, which increased to 20 in generation 12. The average number of En-1 insertions increased only slightly in the population, due to a gradual accumulation of segregants that lost the transposable element. During the development of the En-1 mutagenised population the element remained active even in the high-copy lines. In situ hybridisation demonstrated that multiple En-1 insertions were distributed over all Arabidopsis chromosomes. From the initial En-1 mutagenised populations many unstable gene mutations were recovered, indicating that En-1 can be used as a efficient tool for gene tagging in Arabidopsis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006082009151
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  • 73
    Digitale Medien
    Digitale Medien
    Macromolecular organization and genetic mapping of a rapidly evolving chromosome-specific tandem repeat family (B77) in cotton (Gossypium) (1998)
    Springer
    Plant molecular biology 38 (1998), S. 1031-1041 
    Details
    ISSN: 1573-5028
    Schlagwort(e): evolution ; fluorescence in situ hybridization (FISH) ; genome ; repetitive DNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Isolation and characterization of the most prominent repetitive element families in the genome of tetraploid cotton (Gossypium barbadense L; [39]) revealed a small subset of families that showed very different properties in tetraploids than in their diploid progenitors, separated by 1-2 million years. One element, B77, was characterized in detail, and compared to the well-conserved 5S and 45S rRNA genes. The 572 bp B77 repeat was found to be concentrated in several discontinuous tandem arrays confined to a single 550 kb SalI fragment in tetraploid cotton. Genetic mapping based on the absence of the pentameric ‘rung’ in the G. barbadense ‘ladder’ showed that B77 maps to a D-subgenome chromosome. In situ hybridization supports the contention that the array is confined largely to a single chromosomal site in the D-subgenome. The B77 repeat has undergone a substantial increase in copy number since formation of tetraploid cotton from its diploid relatives. RFLPs observed among tetraploid cotton species suggest that amplification and/or rearrangement of the repeat may have continued after divergence of the five tetraploid cotton species. B77 contains many short direct repeats and shares significant DNA sequence homology with a Nicotiana alata retrotransposon Tna1-2 integrase motif. The recent amplification of B77 on linkage group D04 suggests that the D-subgenome of tetraploid cotton may be subject to different evolutionary constraints than the D-genome diploid chromosomes, which exhibit few genome-specific elements. Further, the abundance of B77 in G. gossypioides supports independent evidence that it may be the closest extant relative of the D-genome ancestor of cotton.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006073116627
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  • 74
    Digitale Medien
    Digitale Medien
    The phenology of fine root growth in a maple-dominated ecosystem: relationships with some soil properties (1998)
    Springer
    Plant and soil 201 (1998), S. 59-69 
    Details
    ISSN: 1573-5036
    Schlagwort(e): maple ; moisture ; phenology ; root growth ; soil fertility ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A two-year study was undertaken in a maple-dominated watershed of southern Québec, Canada, to examine relationships between trends in fine root growth, stem diameter growth, soil moisture, soil temperature, mineralized-N and extractable-P. Until September, soil temperature was consistently higher in 1995 than in 1994. Apart from the first sampling in mid-May, soil moisture was higher in 1994 than in 1995. In 1994, most fine roots were produced before leaf expansion, whereas in 1995, fine root production peaked in July. Annual fine root production was estimated to be 2.7 times higher in 1994 than in 1995. Stem growth was strongly associated with the seasonal and annual variation in soil temperature. Root and diameter growth were asynchronous in 1994 but not in 1995. Fine root production was associated with two groups of variables: a soil fertility (mineralized-N and extractable-P) group and a physical soil environment (moisture and temperature) group. Our results are consistent with the negative effect of high soil-N fertility on fine root production but are inconclusive as to the positive effect of high soil-P fertility. Soil conditions that are detrimental to root growth such as high N availability and anaerobiosis could modify the normal dynamics of fine root growth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004351705516
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  • 75
    Digitale Medien
    Digitale Medien
    Properties and functions of the cyanogenic system in higher plants (1990)
    Springer
    Euphytica 48 (1990), S. 25-43 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Cultivated plants ; wild plants ; cyanogenesis ; ecology ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Cyanogenesis, the production of HCN is a trait that can be found in all the major taxa. The system is particularly important in higher plants, both in view of the specialized mechanisms found in plants and with regard to the physiological and ecological function of HCN production. The present paper discusses the long history of cyanogenic research, the distribution of the cyanogenic substances among the taxa of higher plants, their localisation in the plant organs and their biosynthetic pathways. The same topics are discussed with regard to the specialized β-glucosidases found in plants that play a role in the catabolism of the cyanogenic substances and in HCN production. The physiological and ecological functions of the cyanogenic systems are discussed with emphasis on the few species studied so far that are polymorphic, i.e. contain cyanogenic and acyanogenic individuals in the same population. Although research in this area is still in its infanthood, it is clear that cyanogenesis is part of a complex system that among others, gives protection against particular groups of herbivores. Apparently the defensive system is under some kind of constraint, developmental, selectional, or both, that prevents plants from having an absolute defense against herbivores. One such constraint viz. a negative effect of the cyanogenic system on growth and/or reproduction is discussed in some length. A number of cultivated species, i.e. cassava (Manihot esculenta), sorghum (Sorghum spp) and lima bean (Phaseolus lunatus) to mention a few, are cyanogenic. Cyanogenesis in species used for human or lifestock consumption is generally considered an undesirable trait. On the other hand low levels of cyanogenesis may cause greater susceptibility to herbivores and consequently lower the yield. Apparently cyanogenesis is a character of interest for plant breeders trying to improve cyanogenic species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00028958
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  • 76
    Digitale Medien
    Digitale Medien
    Root and shoot elongation of rhizotron-grown seedlings of Eucalyptus nitens and Eucalyptus globulus in relation to temperature (1998)
    Springer
    Plant and soil 206 (1998), S. 37-46 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Eucalyptus globulus ; Eucalyptus nitens ; root apical diameter ; root elongation ; shoot elongation ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Information on the growth response of a crop plant in relation to temperature can be helpful in selecting genotypes to suit local environments, scheduling favourable time of planting and forecasting growth and yield. To determine the effects of varying temperature on root and shoot elongation of eucalypt seedlings, elongation rates of roots and shoots were measured in rhizotrons for two species (Eucalyptus nitens (Deane and Maiden) Maiden, and Eucalyptus globulus Labill.) at a temperature range of 5–23 °C. Within this range of temperatures, elongation rates of roots and shoots of both species increased with an increase in temperature. Roots of E. globulus were more sensitive and shoots less sensitive to temperature than those of E. nitens. However, the threshold temperature corresponding with zero elongation rate predicted from the regression of elongation rate against temperature was similar for the roots (∼5 °C) and shoots (∼0 °C) of both species. Hysteresis did not appear to have a significant influence on root or shoot elongation of both species during warming compared with cooling. Results are discussed highlighting the importance of the interaction between development and growth of plant components.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004337121719
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  • 77
    Digitale Medien
    Digitale Medien
    The response of soil microorganisms and roots to elevated CO2 and temperature in a terrestrial model ecosystem (1998)
    Springer
    Plant and soil 202 (1998), S. 251-262 
    Details
    ISSN: 1573-5036
    Schlagwort(e): climate change ; Ecotron ; microbial biomass ; microbial community structure ; soil enzymes ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract We investigate the response of soil microorganisms to atmospheric CO2 and temperature change within model terrestrial ecosystems in the Ecotron. The model communities consisted of four plant species (Cardamine hirsuta, Poa annua, Senecio vulgaris, Spergula arvensis), four herbivorous insect species (two aphids, a leaf-miner, and a whitefly) and their parasitoids, snails, earthworms, woodlice, soil-dwelling Collembola (springtails), nematodes and soil microorganisms (bacteria, fungi, mycorrhizae and Protista). In two successive experiments, the effects of elevated temperature (ambient plus 2 °C) at both ambient and elevated CO2 conditions (ambient plus 200 ppm) were investigated. A 40:60 sand:Surrey loam mixture with relatively low nutrient levels was used. Each experiment ran for 9 months and soil microbial biomass (Cmic and Nmic), soil microbial community (fungal and bacterial phospholipid fatty acids), basal respiration, and enzymes involved in the carbon cycling (xylanase, trehalase) were measured at depths of 0–2, 0–10 and 10–20 cm. In addition, root biomass and tissue C:N ratio were determined to provide information on the amount and quality of substrates for microbial growth. Elevated temperature under both ambient and elevated CO2 did not show consistent treatment effects. Elevation of air temperature at ambient CO2 induced an increase in Cmic of the 0–10 cm layer, while at elevated CO2 total phospholipid fatty acids (PLFA) increased after the third generation. The metabolic quotient qCO2 decreased at elevated temperature in the ambient CO2 run. Xylanase and trehalase showed no changes in both runs. Root biomass and C:N ratio were not influenced by elevated temperature in ambient CO2. In elevated CO2, however, elevated temperature reduced root biomass in the 0–10 cm and 30–40 cm layers and increased N content of roots in the deeper layers. The different response of root biomass and C:N ratio to elevated temperature may be caused by differences in the dynamics of root decomposition and/or in allocation patterns to coarse or fine roots (i.e. storage vs. resource capture functions). Overall, our data suggests that in soils of low nutrient availability, the effects of climate change on the soil microbial community and processes are likely to be minimal and largely unpredicatable.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004309623256
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  • 78
    Digitale Medien
    Digitale Medien
    Predominance of ecophysiological controls on soil CO2 flux in a Minnesota grassland (1998)
    Springer
    Plant and soil 207 (1998), S. 77-86 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Cedar Creek ; Minnesota ; light ; root respiration ; Scizachyrium scorparium ; soil CO2 flux ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Ecosystem studies often study soil CO2 flux as a function of environmental factors, such as temperature, that affect respiration rates by changing the rate of utilization of carbon substrates. These studies tend not to include factors, such as photosynthesis, that affect the supply of carbon substrates to roots and root-associated processes. We examined the role of decreased carbohydrate source on soil CO2 flux and root respiration in an annually-burned grassland through manipulations of light intensity and removal of above ground biomass. We also quantified the contribution of root respiration to soil CO2 flux by measuring the respiration rates of excised roots. Two days of shading caused a 40% reduction in soil CO2 flux, while clipping was associated with a 19% reduction in soil CO2 flux. Both reductions were independent of soil and air temperature at the time of measurement. The relative decrease in soil CO2 flux observed in the clipping experiment was similar in magnitude to an observed decrease in root respiration per gram of root, linking decreased root activity and soil CO2 flux. From these experiments, we conclude that variation in factors that affect carbon availability to roots can be important determinants of soil CO2 flux and should be included explicitly in studies that measure or model soil CO2 flux.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004417419288
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  • 79
    Digitale Medien
    Digitale Medien
    Cytoplasmic-genetic male sterility in radish (Raphanus sativus L.). Identification of maintainers, inheritance of male sterility and effect of environmental factors (1990)
    Springer
    Euphytica 47 (1990), S. 171-177 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Raphanus sativus ; radish ; cytoplasmic-genetic male sterility ; environmental influence on male sterility ; inheritance ; maintainer lines ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Research has been carried out on identification of maintainers for cytoplasmic-genetic male sterile lines in Japanese and European radish, on the mode of inheritance of male sterility and on the effect of environmental factors on the expression of this character. In a Japanese radish population and in most early European radish populations maintainers were found in high frequency. Segregations for male sterility in full-sib families, obtained by crossing male sterile and male fertile plants, and in backcross generations, indicated that male sterility is probably determined by one dominant and two recessive independently acting genes, but also minor genes may be involved. The expression of male sterility was not affected by seasonal influences. In some populations a reversible temperature effect was found, most ms plants occurred at 10, 14 and 26°C and most mf plants at 17 and 20°C.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00038833
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  • 80
    Digitale Medien
    Digitale Medien
    The photosynthesis of Dunaliella parva Lerche as a function of temperature, light and salinity (1990)
    Springer
    Hydrobiologia 197 (1990), S. 165-172 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Dunaliella parva ; net photosynthesis ; light ; temperature ; salinity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The photosynthetic behaviour of Dunaliella parva Lerche from the athalassic lagoon of Fuente de Piedra (Málaga, Southern Spain) was studied experimentally at three NaCl concentrations (1, 2 and 3 M), five temperatures (15, 23, 31, 38 and 42°C) and nine different irradiances between 82 and 891 mol m−2 s−1. Results are analyzed to define the best growing conditions for the algae. D. parva shows the highest photosynthetic rates at a NaCl molarity of 2 M, under a moderate light intensity (600 mol m−2 s−1) at 31°C. Above this light intensity a clear photoinhibition of the photosynthesis was found at 2 M and 3 M of NaCl. D. parva is a halotolerant and a thermoresistant species as evidenced by its net photosynthesis rate and positive values of oxygen evolution at 42°C. Two methods for modelling photosynthesis vs. irradiance curves are discussed. The first is a single model, based on third-order polynomial equations, and the second is double model, based on hyperbolical Michaelis-Menten type functions and negative exponential to define photoinhibition.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00026948
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  • 81
    Digitale Medien
    Digitale Medien
    The relation of biotic and abiotic interactions to eutrophication in Tjeukemeer, The Netherlands (1990)
    Springer
    Hydrobiologia 191 (1990), S. 29-37 
    Details
    ISSN: 1573-5117
    Schlagwort(e): total-P ; chlorophyll a ; Daphnia hyalina ; temperature ; predation ; smelt ; bream ; hydrology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract During the summer months of 1974–1985 chlorophyll-a and total P concentration, biomass of Daphnia hyalina, smelt Osmerus eperlanus, bream Abramis brema and pikeperch Stizostedion lucioperca, water temperature and water intake from lake IJsselmeer were monitored in Tjeukemeer. During this period there were manipulations with the bream and pikeperch stocks as a consequence of the termination of a gill-net fishery in 1977, and larval smelt immigrated each year from the large lake IJsselmeer and contributed largely to the yearly smelt recruitment. The correlation matrix of the nine variables mentioned above showed a positive correlation between bream and chlorophyll-a, but surprisingly a negative one between smelt and chlorophyll-a. The latter can only be explained when smelt is the dependent variable. In a multi-linear regression there was a negative effect of temperature, chlorophyll a and pikeperch on smelt and a positive effect of water intake. Daphnia hyalina was negatively influenced by the biomass of smelt and the water intake of lake IJsselmeer. The positive relation of Daphnia hyalina and chlorophyll-a was probably related to better survival chances of D. hyalina in an Oscillatoria-rich environment when smelt is the most important predator. An increasing biomass of bream coincided with higher total-P levels and probably contributed to higher chlorophyll-a levels.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00026036
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  • 82
    Digitale Medien
    Digitale Medien
    In vitro and in situ studies on nitrate disappearance in water-sediment systems of the Camargue (southern France) (1990)
    Springer
    Hydrobiologia 192 (1990), S. 223-232 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Camargue ; denitrification ; nitrate disappearance ; temperature ; organic matter
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Results of in vitro and in situ experiments on nitrate disappearance from water-sediment systems in the Camargue are described. In the in vitro experiments two factors were studied: temperature and organic matter. After a first addition of KNO3 to these sediments, the concentration of organic matter exerted a strong influence on the disappearance rate of nitrate at 25 °C and 15 °C but not at 2 °C. After a second addition of nitrate at 25 °C and 15 °C the denitrification rate increased by approximately 10%, probably because the activity of the bacterial population had increased. Experiments in situ in freshwater temporary marshes showed that nitrate disappeared at approximately twice the rate at similar temperature in vitro. After the first addition of nitrate in the in vitro experiments the concentration of nitrite in the water above the sediment reached about 10% of the concentration of total dissolved inorganic nitrogen at 2 °C and 15 °C. These high concentrations were not found after the first addition at 25 °C or after the second addition of nitrate at 25 °C and 15 °C. In the in situ experiments, however, high concentrations of nitrite were found.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00006017
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  • 83
    Digitale Medien
    Digitale Medien
    Factors affecting the hatching ofStreptocephalus macrourus Daday (Crustacea; Eubranchiopoda) eggs (1990)
    Springer
    Hydrobiologia 194 (1990), S. 13-22 
    Details
    ISSN: 1573-5117
    Schlagwort(e): anostracan ; egg hatching ; light ; temperature ; desiccation ; dissolved oxygen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A major drawback to the use in aquaculture of members of the Eubranchiopoda from temporary pool environments is that their eggs do not hatch readily. An investigation of the factors influencing the hatching of eggs of the fairy shrimpStreptocephalus macrourus, showed that light was the only factor of those investigated that was obligatory for hatching. It was found that eggs which had not been desiccated hatched successfully in the presence of absence of adults, while those which had been desiccated showed a block in hatching initially, although this block deteriorated with time and after approximately two months the eggs which had been desiccated showed a similar hatching success to that of the non-desiccated eggs. Exposure of eggs to extremes of heat or cold before incubation did not influence the hatching success of the eggs significantly, but the temperature at which incubation took place was important. The optimal range lay between 14 °C and 20 °C. Eggs hatched and nauplii survived at dissolved oxygen tensions of below 0.5 mg 1−1
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00012108
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  • 84
    Digitale Medien
    Digitale Medien
    Phylogenetic relationships of phylum Rotifera with emphasis on the families of Bdelloidea (1998)
    Springer
    Hydrobiologia 287-388 (1998), S. 101-107 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Acanthocephala ; aschelminthes ; cladistics ; evolution ; Gnathostomulida ; phylogeny ; pseudocoelomates ; Rotifera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We investigated phylogenetic relationships of phylum Rotifera using cladistic analysis to uncover all most-parsimonious trees from a data set comprising 60 morphological characters of nine taxa: one Acanthocephala, six Rotifera, and two outgroups (Turbellaria, Gnathostomulida). Analysis of our matrix yielded a single most-parsimonious tree. From our analysis we conclude the following: (1) Class Digononta is paraphyletic; (2) it is still premature to reject rotiferan monophyly; (3) the classification hierarchy that best conforms to this morphologically based, cladistic analysis is similar to several traditional schemes. In spite of these results, it is significant that this analysis yielded a tree that is incongruent with those trees developed from molecular data or by using the principles of evolutionary taxonomy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017057619574
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  • 85
    Digitale Medien
    Digitale Medien
    Cross-mating tests re-discovered: a tool to assess species boundaries in rotifers (1998)
    Springer
    Hydrobiologia 287-388 (1998), S. 109-115 
    Details
    ISSN: 1573-5117
    Schlagwort(e): behavior ; mating ; evolution ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The recent isolation of a mate recognition pheromone in the marine rotifer Brachionus plicatilis Müller has shed new light on the mate recognition system of rotifers. One result is improved understanding of the importance of mating behavior as a highly efficient process used by rotifers to choose conspecifics. There are many differences in the main characteristics of mating behavior in members of five different families of rotifers. The present work describes the use of these characteristics to assess species boundaries, especially where boundaries between two or more species are unclear. The method proposed here can assess quantitatively the response of males of one species to females of a questionable taxon by measuring the percentage of matings initiated and the number of completed copulations. The data generated can then be used together with molecular, morphological, and other data to determine the species boundaries. This approach can help distinguish between morphological differences resulting from evolutionary divergence of species and morphological differences induced by environmental or ecological factors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017005602735
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  • 86
    Digitale Medien
    Digitale Medien
    Adjustment of thylakoid plastoquinone content and Photosystem I electron donor pool size in response to growth temperature and growth irradiance in winter rye (Secale cereale L.) (1998)
    Springer
    Photosynthesis research 56 (1998), S. 209-221 
    Details
    ISSN: 1573-5079
    Schlagwort(e): electron donor pool size ; irradiance ; Photosystem I ; plastoquinone ; temperature ; stoichiometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Winter rye (Secale cereale L. cv Musketeer) grown at 5 °C/250 µmol photons m−2 s−1 exhibited a relative reduction state of PS II comparable to that of rye grown at 20 °C but high light (800 µmol photons m−2 s−1) (1-qP = 0.32) whereas winter rye grown at 20 °C/250 µmol photons m−2 s−1 exhibited values of 1-qP (≈ 0.15) comparable to plants grown at 5 °C but low light (50 µmol photons m−2 s−1). The apparent size of the electron donor pool to PS I, estimated either in vivo or in vitro in the presence of methylviologen by ΔA820 was positively correlated with the relative reduction state of PS II under the steady-state growth conditions. Immunoblotting of rye thylakoid polypeptides indicated that the relative contents of Lhcb1, Lhcb2, D1, Cyt f, PC, PsaA/PsaB heterodimer and the β-subunit of ATPase complex exhibited minimal changes on a Chl basis. In contrast, a 2-fold increase in plastoquinone A content was associated with increasing growth irradiance at growth temperatures of either 5 or 20 °C. We suggest that the increases in the apparent size of the electron donor pool to PS I associated with rye grown at either 5 °C/250 µmol photons m−2 s−1or 20 °C/800 µmol photons m−2 s−1 may be explained by an increased thylakoid plastoquinone A content, coupled with possible enhanced PS I cyclic electron transport and/or increased capacity for electron donation from the stroma to the intersystem electron transport chain. The results are discussed with respect to photosynthetic adjustment to changes in PS II ‘excitation pressure’ in winter rye.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006049925042
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  • 87
    Digitale Medien
    Digitale Medien
    Solubility of oxygen in the Dead Sea brine (1990)
    Springer
    Hydrobiologia 197 (1990), S. 99-104 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Oxygen ; solubility ; brines ; temperature ; methods
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The solubility of the O2 in the Dead Sea brine was determined over the temperature range 5 °C–50 °C using a modified Winkler titration, volumetric analysis, and a polarographic sensor. The solubility at room temperature and 1 atmosphere pressure was ca. 1 mg l−1, and the temperature coefficient 0.006 mg 1−1° C−1 . The data are nearly consistent with sea water solubility extrapolated to Dead Sea brine salinity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00026942
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  • 88
    Digitale Medien
    Digitale Medien
    Growth, photosynthesis and agar in wild-type strains of Gracilaria verrucosa and G. conferta (Gracilariales, Rhodophyta), as a strain selection experiment (1990)
    Springer
    Hydrobiologia 204-205 (1990), S. 381-387 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Gracilaria ; growth ; light ; photosynthesis ; RuBPcase ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The local species Gracilaria conferta and the foreign G. verrucosa were grown together under a wide range of photon flux density and temperature conditions. Gracilaria verrucosa showed a higher growth rate, especially under low temperatures, and higher photosynthetic performances as well as higher ribulose-1,5-bisphosphate carboxylase activity as compared with G. conferta. Gracilaria verrucosa also showed a better quality and yield of agar, suggesting that this species could be more suitable than G. conferta for outdoor cultivation in Israel and may improve winter growth in ponds. Growth rate and agar quality (gel strength) were rated as the most suitable characteristics influencing the preference of strains for outdoor cultivation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00040260
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  • 89
    Digitale Medien
    Digitale Medien
    The life cycle of Laminaria abyssalis (Laminariales, Phaeophyta) in culture (1990)
    Springer
    Hydrobiologia 204-205 (1990), S. 461-466 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Brazil ; culture ; Laminaria ; photon flux density ; seaweed ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Laminaria abyssalis occurs in deep water in tropical latitudes of the Brazilian coast (19° 23′ S, 38° 28′ W to 22° 54′ S, 42° 13′ 09″ W). Its life cycle has been completed in the laboratory in seven months using different conditions of light and temperature. The gametophytic stage required for growth the low photon flux density of 1.2 ± 0.3 µmol m−2 s−1 and 18 °C, while the juvenile and adult sporophytes needed 15 µmol m−2 s−1 and 18 °C. The sporophytes became fertile at 23 °C. Our results showed that light and temperature are the main factors regulating the growth and life history of this species under the culture conditions tested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00040271
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  • 90
    Digitale Medien
    Digitale Medien
    Effects of thermal environment on Electromyographical signals obtained from Atlantic salmon (Salmo salar L.) during forced swimming (1998)
    Springer
    Hydrobiologia 371-372 (1998), S. 225-232 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Salmo salar ; electromyogram ; EMG ; temperature ; biotelemetry ; swimming
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Hatchery-reared Atlantic salmon (Salmo salar) were acclimated to 8 °C and 18 °C for 1 month prior to surgical implantation of telemetry devices that measured electromyographical (EMG) impulses. Transmitters were 5 cm long, 1.6 cm diameter and weighed 18 g in air. The teflon coated, stainless steel bipolar electrodes were secured in place using gold tips (9 carat, 5 × 1 mm), that acted as anchors in the locomotory musculature. The electrodes were placed in the red muscle band, half way down the body length of the fish, approximately 5–10 mm apart. Transmitters emitted a signal when the electrical difference between the 2 electrodes exceeded a factory determined threshold, thus, EMG pulse interval (ms) was related to the rate of muscle contraction. Fish were maintained at their respective of muscle contraction. Fish were acclimation temperatures and EMG signals were monitored over a 4-month period during critical swimming speed tests (Ucrit's). Mortality rates were higher in the 18 ° C acclimated group (50% after 3 months), compared to the 8 °C group (0%), probably due to the lack of feeding in the former group. No tags were expelled during this period. Critical swim speed did not change over time or with temperature. EMG pulse intervals were correlated to swimming speed, and became significantly shorter (indicating greater activity) at higher speeds. The relationship of 6 out of 7, 8 °C-acclimated fish, compared to only 1 out of 3, 18 °C-acclimated salmon, remained constant over the 4 month period. These results suggest that care needs to be taken when extrapolating calibration data from the laboratory to the field over long periods of time, especially if changes in the muscle properties of the fish are likely to occur.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017059913366
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  • 91
    Digitale Medien
    Digitale Medien
    Forecasting of water quality in lakes: a predictive use of a one dimensional model. Application to lake Bourget (Savoie, France) (1998)
    Springer
    Hydrobiologia 373-374 (1998), S. 47-60 
    Details
    ISSN: 1573-5117
    Schlagwort(e): lake ; predictive modelling ; water quality forecasting ; temperature ; phosphorus ; dissolved oxygen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In order to assess the efficiency of eutrophication control programs, predictive models are necessary. We propose a methodology for implementing such a model, based on the coupling of a biogeochemical model of a lake and the use of long term time series of meteorological data. This methodology is applied to lake Bourget (Savoie, France). It allows to obtain both mean and standard deviation (first and second order moments) of the state variables of the model on a 1 y period. The sensitivity of the model to the various forcing variables, as well as to the initial conditions is analyzed as well as the linear or non-linear behavior of the model. Finally, the propagation of the uncertainties (standard deviations) in time and space, for both water temperature and dissolved oxygen are assessed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017088125487
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  • 92
    Digitale Medien
    Digitale Medien
    Hysteresis in the temperature response of carbon dioxide and methane production in peat soils (1998)
    Springer
    Biogeochemistry 43 (1998), S. 253-272 
    Details
    ISSN: 1573-515X
    Schlagwort(e): carbon dioxide ; hysteresis ; methane ; peat ; temperature ; wetlands
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Geologie und Paläontologie
    Notizen: Abstract The ability to predict the effects of climate change on trace gas fluxes requires a knowledge of microbial temperature responses. However, the response of a microbial community to temperature in a given substrate may be complicated by its thermal history. To examine the effect of sequentially changing temperature on methane and carbon dioxide production in different peat types, we incubated anaerobic peat samples from 3 types of northern peatlands, a bog, a sedge fen and a cedar swamp, in both rising and falling temperature regimes. Graphic and statistical comparisons of the different temperature regimes suggest hysteresis in microbial response to temperature, although the absolute rates at any given temperature often did not differ. Where regressions for temperature response (Arrhenius plots) were significant, they generally differed between temperature regimes. The greatest differences among treatments occurred during the first half of the 40-d incubation. Increases in carbon dioxide production were similar across all peat types, but methanogenesis varied widely: methane production was uniformly low in the bog peat but increased sharply with temperature in the other two peat types. The complicating effect of history or chronology on substrate responses to environmental stimuli may restrain our ability to model the responses of complex systems to changing conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006097808262
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  • 93
    Digitale Medien
    Digitale Medien
    Cross-mating tests re-discovered: a tool to assess species boundaries in rotifers (1998)
    Springer
    Hydrobiologia 387-388 (1998), S. 109-115 
    Details
    ISSN: 1573-5117
    Schlagwort(e): behavior ; mating ; evolution ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The recent isolation of a mate recognition pheromone in the marine rotifer Brachionus plicatilis Müller has shed new light on the mate recognition system of rotifers. One result is improved understanding of the importance of mating behavior as a highly efficient process used by rotifers to choose conspecifics. There are many differences in the main characteristics of mating behavior in members of five different families of rotifers. The present work describes the use of these characteristics to assess species boundaries, especially where boundaries between two or more species are unclear. The method proposed here can assess quantitatively the response of males of one species to females of a questionable taxon by measuring the percentage of matings initiated and the number of completed copulations. The data generated can then be used together with molecular, morphological, and other data to determine the species boundaries. This approach can help distinguish between morphological differences resulting from evolutionary divergence of species and morphological differences induced by environmental or ecological factors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017005602735
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  • 94
    Digitale Medien
    Digitale Medien
    Phylogenetic relationships of phylum Rotifera with emphasis on the families of Bdelloidea (1998)
    Springer
    Hydrobiologia 387-388 (1998), S. 101-107 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Acanthocephala ; aschelminthes ; cladistics ; evolution ; Gnathostomulida ; phylogeny ; pseudocoelomates ; Rotifera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We investigated phylogenetic relationships of phylum Rotifera using cladistic analysis to uncover all most-parsimonious trees from a data set comprising 60 morphological characters of nine taxa: one Acanthocephala, six Rotifera, and two outgroups (Turbellaria, Gnathostomulida). Analysis of our matrix yielded a single most-parsimonious tree. From our analysis we conclude the following: (1) Class Digononta is paraphyletic; (2) it is still premature to reject rotiferan monophyly; (3) the classification hierarchy that best conforms to this morphologically based, cladistic analysis is similar to several traditional schemes. In spite of these results, it is significant that this analysis yielded a tree that is incongruent with those trees developed from molecular data or by using the principles of evolutionary taxonomy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017057619574
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  • 95
    Digitale Medien
    Digitale Medien
    Physiological tolerances of juvenile robust redhorse, Moxostoma robustum: conservation implications for an imperiled species (1998)
    Springer
    Environmental biology of fishes 51 (1998), S. 429-444 
    Details
    ISSN: 1573-5133
    Schlagwort(e): fish ; Catostomidae ; temperature ; salinity ; pH ; hypoxia ; conservation biology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The robust redhorse, Moxostoma robustum (Teleostei: Catostomidae), is an imperiled sucker native to large rivers of the Atlantic slope of the southeastern United States. Juvenile M. robustum were tested for tolerances to temperature, salinity, pH, and hypoxia in order to evaluate basic early life-history requirements. Static (acute) tests resulted in estimates of mean lower temperature tolerances (5.3–19.4 °C) that varied with prior thermal acclimation and indicated no apparent difference in tolerance among fish 30, 60, and 90 days old. Fish acclimated to 20 °C and 30 °C had significantly different mean critical thermal maxima (34.9 °C and 37.2 °C, respectively) and exhibited pronounced increased opercular ventilation rates with elevated temperatures. Fish exposed to acute and chronic increases in salinity showed unusual patterns of mortality above the isosmotic point (9 ppt) that reflected possible differences in body mass and prior acclimation conditions (i.e., water ionic composition); small fish and those held in soft water were the least tolerant of increased salinity. Abrupt exposure to extreme pH values resulted in greater than 50% mortality at pH values below 4.3 and above 9.5 within a 96-hour period. Fish exposed to progressive hypoxia utilized aquatic surface respiration at a mean oxygen concentration of 0.72–0.80 mg O2 l-1 (20 °C and 30 °C acclimated fish, respectively), and lost equilibrium at 0.54–0.57 mg O2 l-1. Juvenile M. robustum are moderately tolerant of a wide range of ambient physicochemical parameters, but further research is needed to determine how both abiotic and biotic factors have contributed to population decline and extirpation of this species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007486632102
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  • 96
    Digitale Medien
    Digitale Medien
    Factors influencing otolith strontium/calcium ratios in Anguilla japonica elvers (1998)
    Springer
    Environmental biology of fishes 52 (1998), S. 299-303 
    Details
    ISSN: 1573-5133
    Schlagwort(e): eel ; salinity ; temperature ; fish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of temperature and salinity on the concentration ratios of strontium (Sr) to calcium (Ca) within the sagittal otoliths of elvers of the Japanese eel, Anguilla japonica, were studied by spot analysis using a wavelength dispersive X-ray electron microprobe. A total of 340 elvers were used: 100 elvers were reared for 15 days under various salinity conditions (freshwater, one-third seawater, two-thirds seawater and pure seawater at 22 °C; 240 elvers were reared for 58 days under various water temperature conditions (12, 17, 22, 27 °C) in either freshwater or pure seawater. Otolith Sr/Ca ratios were found to be positively correlated with water salinity. On the other hand, the Sr/Ca ratios were not found to be significantly different among the various temperature groups. The above results strongly suggest that the physiological mechanism of incorporation of Sr and Ca within the otolith of an eurythermal fish, Japanese eel, does not change within this range of temperatures (12–27 °C).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007415420540
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  • 97
    Digitale Medien
    Digitale Medien
    Effects of food deprivation on white muscle energy reserves in rainbow trout (Oncorhynchus mykiss): the relationships with body size and temperature (1998)
    Springer
    Fish physiology and biochemistry 19 (1998), S. 239-245 
    Details
    ISSN: 1573-5168
    Schlagwort(e): Oncorhynchus mykiss ; fasting ; metabolites ; temperature ; scaling ; body size ; nutritional status ; glycogen ; glucose ; ATP ; phosphocreatine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The relationship between body size and the depletion of white muscle metabolites (e.g., PCr, ATP, glucose and glycogen) was examined in two sizes (30 or 700 g) of rainbow trout deprived of food for one, four or seven days at either 5 or 15 °C. Following 7 days of food deprivation at 15 °C, the levels of muscle glycogen decreased by approximately 50% in small fish relative to control values (i.e., day 1). In comparison, small fish acclimated to cold temperatures did not exhibit a significant reduction of muscle glycogen over the seven day fasting regime. In contrast to small fish, the levels of white muscle glycogen in large fish remained unchanged after food deprivation, regardless of acclimation temperature. A seven day deprivation of food also resulted in a 50% depletion of white muscle glucose concentrations in small and large fish acclimated to warm temperatures, but there were no significant changes in this variable in fish acclimated to cold temperatures. In contrast to the negative effects of food deprivation on white muscle glycogen and glucose levels, the concentrations of white muscle PCr and ATP were not greatly affected by food deprivation under any of the experimental conditions. Taken together, these results clearly show that food deprivation can have an important influence on the storage of energy metabolites for anaerobic energy production, particularly in small fish at warm temperatures. In the future, it may be very important to consider the physiological effects of short-term food deprivation when interpreting results from studies in which fish have been fasted prior to treatments such as exercise.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007759407275
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  • 98
    Digitale Medien
    Digitale Medien
    The effects of elevated winter temperature and sub-lethal pollutants (low pH, elevated ammonia) on protein turnover in the gill and liver of rainbow trout (Oncorhynchus mykiss) (1998)
    Springer
    Fish physiology and biochemistry 19 (1998), S. 377-389 
    Details
    ISSN: 1573-5168
    Schlagwort(e): rainbow trout ; Oncorhynchus mykiss ; growth ; protein synthesis ; protein degradation ; RNA ; temperature ; pH ; ammonia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Appetite, growth, and protein turnover (synthesis, growth and degradation) of liver and gills were measured in juvenile rainbow trout (Oncorhynchus mykiss) fed to satiation, and exposed for 90 days to elevated winter temperatures (+2 °C above ambient) and either low pH (5.2) in softwater or 70 μM total ammonia (TAmm) in hardwater. All fish increased in weight during the experiments, but those exposed to +2°C grew significantly more than those at ambient temperature due to a stimulation of appetite. During the relatively constant temperature of the first 75 days, +2 °C caused a significant increase in the rates of protein synthesis and degradation in the liver of hardwater-acclimated fish, as a result of an increase in RNA translational efficiency (KRNA). The elevated temperature also induced an increase in gill protein synthesis in softwater-acclimated fish but in this case the underlying mechanism was an increase in Cs, the capacity for protein synthesis (RNA:protein) rather than in KRNA. The addition of 70 μM TAmm had no effect on protein turnover in either liver or gills of hardwater-acclimated fish. Low pH inhibited protein growth in the liver of softwater-acclimated fish at day 90 under both temperature regimes. This inhibition was effected via a decrease in protein synthesis at control temperature but via an increase in protein degradation when the fish were exposed to both low pH and +2 °C. From these results we conclude that a simulated global warming scenario has potentially beneficial rather than detrimental effects on protein turnover and growth of freshwater fish during winter.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007748213387
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  • 99
    Digitale Medien
    Digitale Medien
    Differential effects of photoperiod and temperature on hypothalamic monoaminergic activity in the teleost Channa punctatus (Bloch) (1990)
    Springer
    Fish physiology and biochemistry 8 (1990), S. 291-297 
    Details
    ISSN: 1573-5168
    Schlagwort(e): photoperiod ; temperature ; hypothalamus ; norepinephrine ; dopamine ; 5-hydroxytryptamine ; MAO
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In Channa punctatus maintained under ambient photothermal conditions (10.5L:13.5D; 13 ± 2°C) in the postspawning season, hypothalamic dopamine (DA) and norepinephrine (NE) content varied diurnally, but serotonin (5-HT) and monoamine oxidase (MAO) did not. Exposure of the fish to high temperature (25 ± 2°C), with or without altering the photopheriod, increased the NE and DA content, and NE turnover but decreased DA turnover. Increasing the photoperiod (16L:8D) alone had no significant effect on catecholaminergic (CA) content or activity. When the fish were exposed to long photoperiod, with or without altering the temperature, a day-night variation in 5-HT content and activity was induced in the postspawning season. An increase in temperature alone had no significant effect on 5-HT content or activity. Hypothalamic MAO activity was elevated in fish exposed to high temperature alone, or in combination with long photoperiod, but was not affected significantly by long photoperiod treatment. These results indicate that CA activity is influenced largely by ambient high temperature, whereas serotonergic activity is controlled primarily by photoperiod, with high temperature having an additive effect. MAO activity seems to be influenced by both temperature and photoperiod in this species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00003424
    Standort Signatur Erwartet Verfügbarkeit
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    Digitale Medien
    Digitale Medien
    Differential regulation of 1-aminocyclopropane-1-carboxylate synthase gene family and its role in phenotypic plasticity in Stellaria longipes (1998)
    Springer
    Plant molecular biology 36 (1998), S. 265-274 
    Details
    ISSN: 1573-5028
    Schlagwort(e): 1-aminocyclopropane-1-carboxylic acid synthase (gene mRNA) ; ecotype ; photoperiod ; plasticity ; Stellaria ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Using degenerate oligonucleotides that correspond to conserved amino acid residues of known 1-aminocyclopropane-1-carboxylic acid (ACC) synthases, we cloned a genomic fragment that encodes ACC synthase in Stellaria longipes. Southern analysis suggests that ACC synthase is encoded by a small gene family comprising about 4 members. We isolated four unique ACC synthase cDNA clones under different growth conditions from alpine and prairie ecotypes of S. longipes. Northern analyses suggest that ACC synthase genes are differentially and synergistically regulated by photoperiod and temperature. Such differential regulation of ACC synthase genes positively correlate with the levels of ACC and ethylene. Since ethylene has previously been shown to partly control the stem elongation plasticity in S. longipes, we propose that differential regulation of ACC synthase genes may represent one of the underlying molecular mechanisms of phenotypic plasticity in S. longipes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1005994118535
    Standort Signatur Erwartet Verfügbarkeit
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