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  • Evolution  (188)
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 53 (1989), S. 287-296 
    ISSN: 1570-7458
    Schlagwort(e): European corn borer ; Ostrinia nubilalis ; maize ; water ; drought ; stress ; development ; models ; phytotron ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Des plants de maïs se développent dans un phytotron dans 4 conditions d'humidité du sol (de la saturation à la dessication) et à 3 températures constantes (20°, 25° & 30°C). Chaque pied est contaminé au moment de l'émission du pollen, par une ooplaque d'O. nubilalis Hübn. (ECB) de race européenne E. L'installation, la colonisation et le développement des chenilles sont notés lors de 12 périodes de prélèvements destructifs (4 par température). La vitesse de développement d'O. nubilalis est affectée par la température, main non par l'humidité du sol. Les 4 niveaux d'humidité du sol n'ont aucun effet sur la teneur en eau des tiges de maïs. En fait, les feuilles de maïs présentent une senescence précoce lorsqu'il y a déficit en eau dans le sol. La teneur en eau du sol agit sur l'installation, sur la distribution verticale, la dispersion et le lieu d'alimentation des chenilles; mais ces effets sont légers et ne modifient pas la vitesse de développement. L'environnement larvaire dans la tige de maïs est efficacement isolé des variations externes par l'aptitude de la plante à maintenir la teneur en eau des tiges relativement élevée et stable. Ainsi, des changements importants au niveau du sol n'ont pratiquement pas d'effets sur le développement d'O. nubilalis, malgré les conséquences brutales pour la plante. Cette étude montre que la vitesse de développement d'O. nubilalis est relativement insensible aux modifications de la teneur en eau du sol ainsi qu'aux effets de ce stress de sécheresse sévère sur le pied de maïs. La discussion porte sur l'importance de ces résultats pour la modélisation de la dynamique de l'insecte, la physiologie de la culture et les interactions entre insecte et plante.
    Notizen: Abstract Maize plants were grown under four moisture regimes (wet to extreme deficit) and three constant temperatures (20°, 25° & 30°C) in a phytotron. Each plant was infested with one E-race European corn borer [Ostrinia nubilalis (Hubn.)] (ECB) egg mass at pollen shed. ECB development, location, and establishment were recorded over the course of 12 destructive sample dates (4/temperature). ECB developmental rates were not significantly affected by soil moisture treatments, but were significantly affected by temperature. In spite of successful establishment of four distinctly different soil moisture regimes, the maize stalk tissue water levels were not significantly different among soil water treatments. Instead, the maize plants exhibited accelerated leaf senescence in response to the water deficit conditions. Among the soil water treatments, differences were found in larval establishment, vertical distribution and dispersion, and feeding site selection; however, those effects were slight and could not explain the similarity in ECB developmental rates observed in these treatments. In maize, the larval environment within the stalk was effectively insulated from changes in the external environment by the plant's ability to maintain a relatively high and stable stalk tissue water content. Thus, large changes to the soil environment had essentially no effect on ECB development, though drastic consequences for the plant. This study indicates that ECB rates of development are relatively insensitive to changes in the soil water environment as well as the associated changes in the maize plant that accompany severe drought stress. The significance of these findings to insect modelling, crop physiology, and insect-crop interactions is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of insect behavior 2 (1989), S. 849-852 
    ISSN: 1572-8889
    Schlagwort(e): alternative mating tactics ; temperature ; Stictia heros ; Sphecidae ; Costa Rica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 45 (1989), S. 171-173 
    ISSN: 1420-9071
    Schlagwort(e): Estrogen receptor ; homogenization ; temperature ; nucleus ; uterus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Homogenization of rat uterus at elevated temperatures results in an increased nuclear localization of unoccupied estrogen receptor. This is a nonlinear effect which is accounted for by an increased population of KCl-resistant nuclear binding sites at the elevated homogenization temperatures.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 45 (1989), S. 349-351 
    ISSN: 1420-9071
    Schlagwort(e): Spermatogenesis ; temperature ; brain ; hibernation ; Helix aspersa
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Ablation of the brain from hibernatingHelix aspersa maintained at 25°C causes a significant increase in the proliferation of male cells in the gonad, whereas the ablation of the optic tentacles has no effect. The brain, therefore, produces a factor which specifically inhibits the multiplication of spermatogonia and spermatocytes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1570-7458
    Schlagwort(e): Coleoptera ; Cerambycidae ; Morimus funereus ; development ; laboratory conditions ; food quality ; temperature ; season
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé L'étude a porté sur les effets d'une température constante (23 °C), de la qualité de l'aliment,-B = aliment naturel, c'est-à-dire de l'écorce de chêne pulvérisée; B+C = aliment naturel enrichi avec de la poudre de biscuits sucrés-, et de la saison sur le développement larvaire de M. funereus L. La température de 23 °C a été défavorable aux larves récoltées en septembre dans des souches de chênes et élevées sur aliment B: les larves étaient mortes en 30 jours. Avec aliment B+C, l'effet défavorable a été neutralisé et le poids des larves augmenté de 543%, 897% et 1179% en 1, 2 et 3 mois. Des larves néonates d'été ou d'hiver se sont bien développées sur B+C, mais toutes les larves d'hiver étaient mortes sur B en 40 j. Des larves de mêmes parents, écloses à différentes époques de l'année, ont présenté des différences saisonnières du taux de survie et de la vitesse de développement lors de leur élevage à 23 °C sur B+C. Le développement le plus rapide et la meilleure survie ont été obtenus avec des larves écloses au début ou au milieu de l'été; tandis que le développement le plus lent et la plus mauvaise survie ont été obtenus avec les larves écloses à la fin de l'été. Les changements saisonniers synchrones des adultes et de leurs descendants, exprimés à différents niveaux d'organisation biologique, suggèrent l'existence d'un rythme annuel endogène qui dépend de l'expression de différents gènes au cours du cycle annuel.
    Notizen: Abstract The effects of constant temperature (23 °C), food quality (B, natural diet i.e. powdered oak bark; B+C, natural diet enriched with powdered sweet crackers) and season on larval development of the cerambycid Morimus funereus L. were studied. The temperature of 23 °C exerted an unfavourable effect on larvae collected from oak stumps in September and bred on B; i.e. the larvae died within 30 days. When the larvae consumed B+C the unfavourable effect of temperature was abolished and the larvae increased their weight by 543%, 897% and 1179% in 1, 2 and 3 months, respectively. Newly hatched summerand winter-larvae developed successfully on B+C, while all the winter-larvae died within 40 days on B. Larvae of an identical parentage hatched in different phases of the annual cycle and showed seasonal differences in the rate of development and survival when reared on B+C at 23 °C. The fastest development and the highest survival rate were observed in larvae which emerged in early- and midsummer, whereas the slowest development and the lowest survival rate were in those hatched in late summer. The synchronized seasonal changes of adults and their offspring, as expressed at different levels of biological organization, suggest the existence of an endogenous annual rhythm which is dependent upon the expression of different genes in the course of the annual cycle.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 52 (1989), S. 185-188 
    ISSN: 1570-7458
    Schlagwort(e): Heteroptera ; Dolycoris baccarum ; S. Norwegian population ; adult hibernal diapause ; diapause completion ; diapause activation ; diapause induction ; diapause prevention ; photoperiod ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    ISSN: 1570-7458
    Schlagwort(e): Developmental rates ; temperature ; parasitoid ; mealybug ; Hymenoptera ; Encyrtidae ; Epidinocarsis diversicornis ; Acerophagus coccois ; Homoptera ; Pseudococcidae ; Phenacoccus herreni ; cassava ; yucca
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Les vitesses de développement des oeufs et de tous les stades larvaires mâles et femelles de P. herreni Cox & Williams ont été déterminées à 18°, 20°, 22°, 25°, 30° et 35°C. La longévité des adultes mâles et femelles a été déterminée. Les vitesses de développement de la ponte à la formation du cocon et de celleci à l'émergence de E. diversicornis Howard, encyrtide parasite de P. herreni ont été déterminées à 18°, 20°, 25° et 30°C. Il en a été de même pour un second encyrtide parasite A. coccois Smith à 20°, 25° et 30°C. Les équations polynomiales des derniers carrés dérivés et les équations logistiques ont été ajustées pour chaque lot de données (à l'exception de A. coccois) de façon à ce qu'elles aient pu être interpolées pour analyser l'impact de ces parasites sur la dynamique de population de P. herreni. Les résultats de cette analyse sont présentés à part.
    Notizen: Abstract Developmental rates for Phenacoccus herreni Cox & Williams were determined at 18°, 20°, 22°, 25°, 30° and 35°C for the egg, all juvenile male and all juvenile female stadia. Longevity was determined for adult females and adult males. Developmental rates for the P. herreni parasitoid Epidinocarsis diversicornis (Howard) were determined at 18°, 20°, 25° and 30°C for the oviposition-to-mummy-formation period and the mummy-formation-to-adult-eclosion period. Developmental rates were determined for the P. herreni parasitoid Acerophagus coccois Smith for the same two life stages at 20°, 25° and 30°C. Least-squares-derived polynomial equations or logistic equations were fitted to each data set (except for A. coccois) so that rates could be interpolated for temperatures between observed points for use in an analysis of the impact of these parasitoids on population dynamics of P. herreni. Results of this analysis are presented separately.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 50 (1989), S. 185-193 
    ISSN: 1570-7458
    Schlagwort(e): temperature ; development ; simulation ; phenology ; budmoth ; Zeiraphera canadensis ; Tortricidae ; degree-days
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé La diapause des oeufs de Zeiraphera canadensis Mutuura et Freeman (Lepidoptera: Tortricidae) a été complétée après 15 semaines d'élevage à 0,5°C. A ce stade de leur développement, une température supérieure à 30°C leur est létale. Les relations entre la température et le développement des larves sur l'épinette blanche, Picea glauca (Moench) Voss, et des pupes ont été observées au laboratoire. Les temps de développement les plus courts ont été observés à 28°C. Les larves sont tolérantes à la chaleur et se développent à 32 C, une température qui est létale aux pupes. II y a peu de variabilité des taux de développement de tous les stades immatures. Ceci explique le haut degré de synchronie observé au sein de populations de cet insecte. Un modèle simulant la phénologie a été mis au point et calibré pour prédire la fréquence des divers stades du cycle vital sous des conditions de terrain. La processus de calibration a révélé que la température dans le microhabitat des oeufs est très semblable à celle de l'air, mais que les larves, retrouvées sous l'enveloppe des bourgeons, sont exposées à des températures pouvant excéder celle-ci de plusieurs degrés. Pour des fins de planification du synchronisme entre le développement de l'insecte et des programmes de suivi et de lutte, le nombre de degré-jours nécessaires pour atteindre 10% d'éclosion des oeufs ou 75% d'émergence des adultes ont été estimés à partir d'une température seuil de 4,4°C.
    Notizen: Abstract Diapause requirements of eggs of Zeiraphera canadensis Mutuura and Freeman (Lepidoptera: Tortricidae) are satisfied by 15 weeks of storage at 0.5°C. Temperatures above 30°C are lethal for this life stage. Temperature-dependent development of larvae fed on white spruce, Picea glauca (Moench) Voss, and of pupae was observed under laboratory conditions. The shortest development times were observed at 28°C. Larvae are tolerant to heat, and developed at 32°C, a lethal temperature for pupae. There was little variation of development rates in all stages of the life cycle, explaining the high degree of phenological synchrony reported in populations of this species. A phenological model was developed and calibrated to simulate the relative abundance of the various immature stages under field conditions. The calibration process suggested that temperature in the microhabitat of eggs may be very close to air temperature, but that temperatures under bud caps where larvae are feeding may rise several degrees above air temperature. For the purposes of planning the timing of survey and control practices, degree-day requirements for 10% egg hatch and 75% adult emergence were estimated based on a 4.4°C threshold temperature.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    ISSN: 1432-0983
    Schlagwort(e): psbA ; Cyanelle ; Cyanophora paradoxa ; Evolution ; Sequence analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The psbA gene is part of the reaction center of photosystem II in cyanobacteria and the plastids of higher plants. Its primary sequence is highly conserved among all species investigated so far and its sequence shows homologies with the L and M subunits of the reaction center of photosynthetic bacteria. We have analyzed the psbA homolog from a eukaryotic alga, Cyanophora paradoxa, where the gene is encoded on cyanelle DNA. These cyanelles are surrounded by a murein sacculus and resemble cyanobacteria in many other characteristics, although they are genuine organelles that functionally replace plastids. Analysis of the gene revealed a psbA protein identical in length (360 codons) with the cyanobacterial counterpart. The overall sequence identity is, however, more pronounced between cyanelle psbA and the shorter (353 amino acids) psbA product found in higher plants. These data strongly support the postulated bridge position of cyanelles between chloroplasts and free-living cyanobacteria.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 15 (1989), S. 99-106 
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Isoleucyl-tRNA synthetase ; Isoleucine ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The isoleucyl-tRNA synthetase gene (ILS1) from the yeast Saccharomyces cerevisiae was cloned and sequenced. This gene was initially cloned because it cross-hybridizated to what is now presumed to be the isoleucyl-tRNA synthetase gene (cupC) from the protozoan Tetrahymena hhermophila. The ILS1 gene was determined to be 1,072 amino acids in length. A comparison with a recently published sequence of ILS1 1 from another laboratory (Englisch et al. 1987) was made and differences noted. Two promoter elements were detected, one for general amino acid control and one for constitutive transcription. A heat shock protein (hsp70) gene (probably SSA3) was found 237 by upstream from the ILS1 translation start site. The ILS1 amino acid sequence was compared to isoleucyl-tRNA synthetases from other organisms, as well as to valyl-, leucyl- and methionyl-tRNA synthetases. Regions of conservation between these enzymes were found.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 15 (1989), S. 221-229 
    ISSN: 1432-0983
    Schlagwort(e): Chloroplast DNA ; Chlorophyll a/c alga ; Evolution ; Ribosomal operon
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary There are almost no data describing chloroplast genome organization in chromophytic (chlorophyll a/c) plants. In this study chloroplast ribosomal operon placement and gene organization has been determined for the golden-brown alga Olisthodiscus luteus. Ribosomal RNA genes are located on the chloroplast DNA inverted repeat structure. Nucleotide sequence analysis, demonstrated that in contrast to the larger spacer regions in land plants, the 16S–23S rDNA spacer of O. luteus is only 265 by in length. This spacer contains tRNAIle and tRNAAla genes which lack introns and are separated by only 3 bp. The sequences of the tRNA genes and 16S and 23S rDNA termini flanking the spacer were examined to determine homology between O. luteus, chlorophytic plant chloroplast DNA, and prokaryotes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 28 (1989), S. 175-184 
    ISSN: 1432-1432
    Schlagwort(e): Sheep ; Globin genes ; Evolution ; Gene duplication
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Domestic sheep have two common alleles at the adult β-globin locus,β A andβ B. Here we report the structure of the β-globin locus of A-haplotype sheep. The locus consists of 12 genes, organized as a triplicated 4-gene set: 5′ ∈I-∈II-ΨβI-βC-∈III-∈IV-ΨβII-βA-∈V-∈VI-ΨβIII-βF 3′. This arrangement is identical to that of the closely related goat locus. Sheep with the B haplotype have a locus arrangement consisting of a duplicated four-gene set, lacking the βC gene as well as three other genes present in A sheep and goats. In order to understand the evolutionary history of the B sheep locus, we have sequenced the βB gene from these sheep, and the βB gene from A-haplotype sheep, and compared the sequences to those of the sheep βA, goat βC, and βA, and cow adult β genes. Our results indicate that the βB gene has diverged recently from the βA gene, and therefore the βB locus structure may have resulted from a recent deletion from a triplicated locus.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    ISSN: 1432-1432
    Schlagwort(e): Evolution ; Multiple sequence alignment ; NTP binding ; Phylogenetic analysis ; Positive-strand RNA viruses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary NTP-motif, a consensus sequence previously shown to be characteristic of numerous NTP-utilizing enzymes, was identified in nonstructural proteins of several groups of positive-strand RNA viruses. These groups include picorna-, alpha-, and coronaviruses infecting animals and como-, poty-, tobamo-, tricorna-, hordei-, and furoviruses of plants, totalling 21 viruses. It has been demonstrated that the viral NTP-motif-containing proteins constitute three distinct families, the sequences within each family being similar to each other at a statistically highly significant level. A lower, but still valid similarity has also been revealed between the families. An overall alignment has been generated, which includes several highly conserved sequence stretches. The two most prominent of the latter contain the socalled “A” and “B” sites of the NTP-motif, with four of the five invariant amino acid residues observed within these sequences. These observations, taken together with the results of comparative analysis of the positions occupied by respective proteins (domains) in viral multidomain proteins, suggest that all the NTP-motif-containing proteins of positive-strand RNA viruses are homologous, constituting a highly diverged monophyletic group. In this group the “A” and “B” sites of the NTP-motif are the most conserved sequences and, by inference, should play the principal role in the functioning of the proteins. A hypothesis is proposed that all these proteins posses NTP-binding capacity and possibly NTPase activity, performing some NTP-dependent function in viral RNA replication. The importance of phylogenetic analysis for the assessment of the significance of the occurrence of the NTP-motif (and of sequence motifs of this sort in general) in proteins is emphasized.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 29 (1989), S. 28-39 
    ISSN: 1432-1432
    Schlagwort(e): Transposable elements ; Zea mays ; Evolution ; Inverted repeats
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The Robertson's Mutator stock of maize exhibits a high mutation rate due to the transposition of theMu family of transposable elements. All characterizedMu elements contain similar ≈200-bp terminal inverted repeats, yet the internal sequences of the elements may be completely unrelated. Non-Mutator stocks of maize have a 20–100-fold lower mutation rate relative to Mutator stocks, yet they contain multiple sequences that hybridize to theMu terminal inverted repeats. Most of these sequences do not cohybridize to internal regions of previously clonedMu elements. We have cloned two such sequences from the maize line B37, a non-Mutator inbred line. These sequences, termedMu4 andMu5, have an organization characteristic of transposable elements and possess ≈200-bpMu terminal inverted repeats that flank internal DNA, which is unrelated to other clonedMu elements.Mu4 andMu5 are both flanked by 9-bp direct repeats as has been observed for otherMu elements. However, we have no direct evidence that they have recently transposed because they have not been found in known genes. Although the internal regions ofMu4 andMu5 are not related by sequence similarity, both elements share an unusual structural feature: the terminal inverted repeats extend more than 100 bp internally fromMu-similar termini. The distribution of these elements in maize lines and related species suggests thatMu elements are an ancient component of the maize genome. Moreover, the structure of theMu termini and the fact thatMu termini are found flanking different internal sequences leads us to speculate thatMu termini once may have been capable of transposing as independent entities.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 29 (1989), S. 52-62 
    ISSN: 1432-1432
    Schlagwort(e): Genome organization ; Evolution ; Plant virus ; RNA recombination ; Sequence similarity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The relationships of genome organization among elongated (rod-shaped and filamentous) plant viruses have been analyzed. Sequences in coding and noncoding regions of barley stripe mosaic virus (BSMV) RNAs 1, 2, and 3 were compared with those of the monopartite RNA genomes of potato virus X (PVX), white clover mosaic virus (WClMV), and tobacco mosaic virus, the bipartite genome of tobacco rattle virus (TRV), the quadripartite genome of beet necrotic yellow vein virus (BNYVV), and icosahedral tricornaviruses. These plant viruses belong to a supergroup having 5′-capped genomic RNAs. The results suggest that the genomic elements in each BSMV RNA are phylogenetically related to those of different plant RNA viruses. RNA 1 resembles the corresponding RNA 1 of tricornaviruses. The putative proteins encoded in BSMV RNA 2 are related to the products of BNYVV RNA 2, PVX RNA, and WClMV RNA. Amino acid sequence comparisons suggest that BSMV RNA 3 resembles TRV RNA 1. Also, it can be proposed that in the case of monopartite genomes, as a rule, every gene or block of genes retains phylogenetic relationships that are independent of adjacent genomic elements of the same RNA. Such differential evolution of individual elements of one and the same viral genome implies a prominent role for gene reassortment in the formation of viral genetic systems.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 16
    ISSN: 1432-1432
    Schlagwort(e): Carcinoembryonic antigen ; Evolution ; Gene family ; Human ; Rat ; Synonymous substitutions ; Silent molecular clock ; Evolutionary trees
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Various rodent and primate DNAs exhibit a stronger intra- than interspecies cross-hybridization with probes derived from the N-terminal domain exons of human and rat carcinoembryonic antigen (CEA)-like genes. Southern analyses also reveal that the human and rat CEA gene families are of similar complexity. We counted at least 10 different genes per human haploid genome. In the rat, approximately seven to nine different N-terminal domain exons that presumably represent different genes appear to be present. We were able to assign the corresponding genomic restriction endonuclease fragments to already isolated CEA gene family members of both human and rat. Highly similar subgroups, as found within the human CEA gene family, seem to be absent from the rat genome. Hybridization with an intron probe from the human nonspecific cross-reacting antigen (NCA) gene and analysis of DNA sequence data indicate the conservation of noncoding regions among CEA-like genes within primates, implicating that whole gene units may have been duplicated. With the help of a computer program and by calculating the rate of synonymous substitutions, evolutionary trees have been derived. From this, we propose that an independent parallel evolution, leading to different CEA gene families, must have taken place in, at least, the primate and rodent orders.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 29 (1989), S. 180-187 
    ISSN: 1432-1432
    Schlagwort(e): Divergence ; Mitochondrial DNA ; Molecular evolution ; Constraints ; Two-parameter model ; Evolutionary distance ; Evolution ; Mutation ; Neutral space ; Variable positions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Selective constraints on DNA sequence change were incorporated into a model of DNA divergence by restricting substitutions to a subset of nucleotide positions. A simple model showed that both mutation rate and the fraction of nucleotide positions free to vary are strong determinants of DNA divergence over time. When divergence between two species approaches the fraction of positions free to vary, standard methods that correct for multiple mutations yield severe underestimates of the number of substitutions per site. A modified method appropriate for use with DNA sequence, restriction site, or thermal renaturation data is derived taking this fraction into account. The model also showed that the ratio of divergence in two gene classes (e.g., nuclear and mitochondrial) may vary widely over time even if the ratio of mutation rates remains constant. DNA sequence divergence data are used increasingly to detect differences in rates of molecular evolution. Often, variation in divergence rate is assumed to represent variation in mutation rate. The present model suggests that differing divergence rates among comparisons (either among gene classes or taxa) should be interpreted cautiously. Differences in the fraction of nucleotide positions free to vary can serve as an important alternative hypothesis to explain differences in DNA divergence rates.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 29 (1989), S. 233-245 
    ISSN: 1432-1432
    Schlagwort(e): Mitochondrial DNA ; Salmonids ; Nucleotide sequence ; Transitions ; Transversions ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Sequence comparisons were made from 2214 bp of mitochondrial DNA cloned from six Pacific salmonid species. These sequences include the genes for ATPase subunit 6, cytochrome oxidase subunit 3, NADH dehydrogenase subunit 3, NADH dehydrogenase subunit 4L, tRNAGLY, and tRNAARG. Variation is found at 338 silent and 12 nonsilent positions of protein coding genes and 10 positions in the two tRNA sequences. A single 3-bp length difference was also detected. In all pairwise comparisons the sequence divergence observed in the fragment was higher than that previously predicted by restriction enzyme analysis of the entire molecule. The inferred evolutionary relationship of these species is consistent between methods. The distribution of silent variation shows a complex pattern with greatly reduced variation at the junctions of genes. The variation in the tRNA sequences is concentrated in the DHU loop. The close relationship of these species and extensive sequence analyzed allows for an analysis of the spectrum of substitutions that includes the frequencies of all 12 possible substitutions. The observed spectrum of substitutions is related to potential pathways of spontaneous substitution. The salmonid sequences show an extremely high ratio of silent to replacement substitutions. In addition the amino acid sequences of the four proteins coded in this fragment show a consistently high level of identity with theXenopus sequences. Taken together these data are consistent with a slower rate of amino acid substitution among the cold-blooded vertebrates when compared to mammals.
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  • 19
    ISSN: 1432-1432
    Schlagwort(e): α-Conotoxin ; α-Neurotoxin ; Erabutoxin b ; Evolution ; Venom
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary α-neurotoxins from elapid snake venoms andα-conotoxins from marine snails bind specifically and with high affinity to nicotinic cholinoceptors. Although both types of toxin are polypeptides, there is more than a fourfold difference in size between the two and no clear sequence homology is evident. A systematic computer search of the three-dimensional structure of erabutoxin b (anα-neurotoxin from the false sea snakeLaticauda semifasciata) was performed to identify the locality that most closely matched the amino acid compositions of the smallerα-conotoxins (from the marine snailsConus magus andConus geographus). The area of greatest similarity centered on residue position 25 of erabutoxin b, a locale that is conserved throughout the snakeα-neurotoxins and their homologues. Six Proteins unrelated to erabutoxin b were compared to theα-conotoxins to show that the extent of the erabutoxin b/α-conotoxin match was too high to be coincidental. Homologues of erabutoxin b, namelyα-cobratoxin fromNaja naja siamensis and cytotoxin VII4 fromNaja mossambica mossambica, were also analyzed. The extent of the matching with theα-conotoxins decreased in the series erabutoxin b〉α-cobratoxin〉cytotoxin VII4, and this also relates the order of similarity to the pharmacological properties of theα-conotoxins. Theα-conotoxin-like area of the snakeα-neurotoxins is peripheral to the site previously considered important for binding to the cholinoceptor, even though it seems to represent the focus of evolutionary convergence between the two types of neurotoxin. The area of resemblance does, however, have strong associations with the conformational behavior of the snake toxins. Hence, the outcome of this study has important consequences for the current ideas on snakeα-neurotoxin structure/activity relationships and the evolutionary origins of neurotoxicity.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Biodegradation 7 (1989), S. 159-193 
    ISSN: 1572-9729
    Schlagwort(e): Brachiopod biogeochemistry ; diagenesis ; secular isotopic variations ; carbon isotopes ; oxygen isotopes ; Sr/Ca ; temperature ; Recent ; Late Paleozoic
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Energietechnik , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Sr/Ca ratios in modern brachiopod shells reflect variations in ambient seawater, whereas their Na contents show no relationship with water depth or habitat. Their Mn and Fe contents are controlled, in part, by leaching of these elements from oxide coatings or the low input/sedimentation rate of detrital material into depositional areas such as Quatsino Sound. For most Carboniferous brachiopods from North America, the Mn and Fe contents are similar to those recorded by their Recent counterparts. The high Mn and Fe contents in the brachiopods from shales suggest several possibilities for these levels. One possibility is the leaching of Mn and Fe from oxide coatings/matrix which was not completely removed in the cleaning process, or the high levels in part reflect unusual depositional conditions (some degree of anoxia) for the local shaly environments. The Sr/Ca ratio of brachiopods and, by inference, complementary seawater, did not vary significantly during the Carboniferous. The Sr/Ca minimum observed in brachiopods of Mississippian age coincides with a dip in the 87Sr/86Sr curve and correlates with the Hercynian orogeny. This is attributed to the cycling of seawater through mid-ocean ridge basalts, and postulated exchange reactions account for variation in the composition of seawater-Ca. The unidirectional trend of heavier δ13C values from the Devonian to the Permian is intricately coupled with the evolution of the terrestrial biomass. In addition to expansion of terrestrial plants, burial of reduced carbon in the form of coal (organic matter) contributed to the observed shift. The start of the Permo-Pennsylvanian glaciation is marked by a negative excursion of the secular carbon trend, which is linked to weathering of reduced carbon and its return to the oceanic reservoir with its oxidized carbon. The oxygen isotope values reflect the unidirectional trend towards higher values of the carbon data with decreasing geologic age. Negative excursions of the trend may be related to extensive weathering of terrestrial and submarine rocks, whereas positive excursions may be related to hydrothermal alteration of submarine rocks and dehydration of oceanic crust during times of active sea-floor spreading. Oxygen-calculated water temperatures of unaltered brachiopod material are unrealistically high for all of the Devonian, and the Chesterian-Meramecian, Desmoinesian-Missourian, and Artinskian Epochs. During these times maximum water temperatures of 42° to 56°C are well above the thermal threshold of protein denaturation. This process, which is lethal to most higher organisms, demands an adjustment in oxygen of -2.5%. for samples older than Missourian, and of -1.250%. for samples spanning the Missourian-Artinskian interval. With these adjustments and salinity considerations made prior to calculations, water temperatures become reasonable for the Late Paleozoic epeiric, tropical seas of North America.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Aquatic sciences 51 (1989), S. 108-128 
    ISSN: 1420-9055
    Schlagwort(e): Chemistry ; mountain lakes ; silica ; acidity ; sediment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Alpine lakes in siliceous catchments of Tyrol and Carinthia (Austria) show signs of acidification. About 9% of the studied lakes have no alkalinity, more than 20% are below pH 6. About two thirds of all lakes have acid neutralizing capacities below 100 μeq 1−1. In spite of moderate precipitation acidity, some lakes show considerable concentrations of dissolved reactive aluminum during or shortly after snowmelt. High altitude lakes of the Alps are definitely more acidic than high mountain lakes in remote areas. Large differences in water and soil chemistry of nearby situated lakes were attributed to heterogeneities of bedrock geology. Paleolimnological investigations on former pH values of five lakes, based on diatom assemblages in the sediment, showed different developments: recent and past acidification, stable conditions, and alkalinization.
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 45 (1989), S. 102-103 
    ISSN: 1420-9071
    Schlagwort(e): Djungarian hamster ; photoperiod ; temperature ; T3 ; T4 ; testosterone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effects of photoperiod, temperature and testosterone treatment on plasma T3 and T4 levels were investigated in the Djungarian hamster. Plasma T3 level was affected by temperature (25°C〈7°C) but not by photoperiod. Plasma T4 level was affected by photoperiod (short day 〈 long day) at 25°C. Administration of testosterone increased plasma T4 level under short photoperiod at 25°C. Thus, higher plasma T4 level under long photoperiod at 25°C might be induced by testosterone.
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 151 (1989), S. 454-458 
    ISSN: 1432-072X
    Schlagwort(e): Photosynthesis ; Photosynthetic bacteria ; Evolution ; Bacteriochlorophyll ; Reaction centres ; Light harvesting
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract 1) A number of overlapping clones have been isolated from a Rhodobacter sphaeroides gene bank. Following conjugative gene transfer from Escherichia coli these clones restore a wild type phenotype to several mutants unable to synthesise bacteriochlorophyll. 2) The insert DNA was analysed by restriction mapping and together the clones form the basis of the first restriction map of the 45 kb photosynthetic gene cluster of Rb. sphaeroides. 3) This cluster is bounded on one side by puh A encoding the reaction centre H polypeptide and on the other by the puf operon encoding reaction centre L and M apoproteins and light harvesting LH1 and polypeptides. 4) DNA fragments from the 45 kb cluster were used to probe genomic DNA from other photosynthetic bacteria. Using heterologous hybridisation conditions, a significant degree of homology is shown between Rb. sphaeroides and these other bacteria, suggesting close evolutionary links with Rb. capsulatus in particular.
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  • 24
    ISSN: 1432-072X
    Schlagwort(e): Eubacteria ; Evolution ; Extreme thermophile ; Thermotoga
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Three new strains of eubacterial hyperthermophiles were isolated from continental solfataric springs at Lac Abbé (Djibouti, Africa). Due to their morphology, lipids, and RNA polymerases they belong to the genus Thermotoga. Strains LA4 and LA10 are closely related to Thermotoga neapolitana found up to now only in the marine environment. Strain LA 3 differs from Thermotoga maritima and Thermotoga neapolitana in significant physiological and molecular properties. It is described as the new species Thermotoga thermarum.
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    The journal of membrane biology 112 (1989), S. 277-289 
    ISSN: 1432-1424
    Schlagwort(e): myelinated nerve fiber ; gating current ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary Asymmetrical displacement currents and Na currents of single myelinated nerve fibers ofXenopus laevis were studied in the temperature range from 5 to 24°C. The time constant of the on-response atE=4 mV,τ on, was strongly temperature dependent, whereas the amount of displaced charge atE=39 mV, Qon, was only slightly temperature dependent. The mean Q10 forτ on -1 was 2.54, the mean Q10 for Qon was 1.07. The time constant of charge immobilization,τ i , atE=4 mV varied significantly (α=0.001) with temperature. The mean Q10 forτ i -1 was 2.71±0.38. The time constants of immobilization of gating charge and of fast inactivation of Na permeability were similar in the temperature range from 6 to 22°C. The Qoff/Qon ratio forE=4 mV pulses of 0.5 msec duration decreased with increasing temperature. The temperature dependence of the time constant of the off-response could not be described by a single Q10 value, since the Q10 depended on the duration of the test pulse. Increasing temperature shifted Qon (E) curves to more negative potentials by 0.51 mVK −1, but shiftedP Na (E) curves andh ∞ (E) curves to more positive potentials by 0.43 and 0.57 mV K−1, respectively.h ∞ (E=−70 mV) increased monotonously with increasing temperature. The present data indicate that considerable entropy changes may occur when the Na channel molecule passes from closed through open to inactivated states.
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 77 (1989), S. 634-640 
    ISSN: 1432-2242
    Schlagwort(e): Isoenzymes ; Evolution ; Domestication ; Biological structure ; Genetic distances
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The survey of enzyme polymorphism in West African pearl millet cultivars reported by Tostain et al. 1987 has been extended to include populations from other regions of Africa and from India. The eight enzyme systems studied included: alcohol dehydrogenase, β-esterase, catalase, phosphoglucoisomerase, phosphoglucomutase, 6-phosphogluconate dehydrogenase, glutamate oxaloacetate transaminase, and malate dehydrogenase. One-hundred-ninety-nine populations of millet were analyzed, including 74 populations studied earlier. No new enzyme diversity was observed. Intrapopulation diversity ranged from 70%–90% of the total diversity, depending on their regions of origin. Four principal groups were distinguished in the following decreasing order of diversity: early-maturing cultivars from West and East Africa, late — maturing cultivars from West and East Africa, cultivars from India, and cultivars from southern Africa. The early-maturing cultivars were distributed between two principal focal points from East Africa in the East to Mali in the West. In the center were found millets from Niger which were most diverse. Indian and southern African cultivars were distinct, with the former appearing relatively similar to those of Niger, and the latter somewhat similar to late-maturing cultivars from West Africa, a diverse group that included late-maturing cultivars from East Africa. Based on the results obtained, an evolutionary hypothesis proposed here includes: multiple domestications in the Sahel, creation of early-maturing cultivars and their migration eastwards to India plus a southwards migration to Sudanian zone, and creation of late-maturing cultivars and their migration simultaneously westwards, eastwards, and southwards to southern Africa.
    Materialart: Digitale Medien
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 77 (1989), S. 844-850 
    ISSN: 1432-2242
    Schlagwort(e): Evolution ; Restriction fragment length polymorphism ; Grasses ; Maize ; Sugarcane
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The structure and organization of the ribosomal DNA (rDNA) of sorghum (Sorghum bicolor) and several closely related grasses were determined by gel blot hybridization to cloned maize rDNA. Monocots of the genus Sorghum (sorghum, shattercane, Sudangrass, and Johnsongrass) and the genus Saccharum (sugarcane species) were observed to organize their rDNA as direct tandem repeats of several thousand rDNA monomer units. For the eight restriction enzymes and 14 cleavage sites examined, no variations were seen within all of the S. bicolor races and other Sorghum species investigated. Sorghum, maize, and sugarcane were observed to have very similar rDNA monomer sizes and restriction maps, befitting their close common ancestry. The restriction site variability seen between these three genera demonstrated that sorghum and sugarcane are more closely related to each other than either is to maize. Variation in rDNA monomer lengths were observed frequently within the Sorghum genus. These size variations were localized to the intergenic spacer region of the rDNA monomer. Unlike many maize inbreds, all inbred Sorghum diploids were found to contain only one rDNA monomer size in an individual plant. These results are discussed in light of the comparative timing, rates, and modes of evolutionary events in Sorghum and other grasses. Spacer size variation was found to provide a highly sensitive assay for the genetic contribution of different S. bicolor races and other Sorghum species to a Sorghum population.
    Materialart: Digitale Medien
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  • 28
    ISSN: 1432-2242
    Schlagwort(e): Wheat aneuploids ; Null forms ; Storage proteins ; Gliadins ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Electrophoretical analyses of the gliadin fraction extracted from seeds of the intervarietal substitution lines of T. aestivum ssp. spelta in the T. aestivum ssp. vulgare cv ‘Chinese Spring’ for the homoeologous groups 1 and 6 and substitution lines of 6D chromosome of ‘Chinese Spring’ in the durum wheat cv ‘Langdon’ allowed the identification of seeds without gliadin proteins controlled by genes on chromosome 6A and 6B. A gliadin component of ‘Chinese Spring’, not previously assigned to any specific chromosome, is controlled by chromosome 6D in the 6D (6A) and 6D (6B) disomic substitution lines of ‘Langdon’. Additional genes controlling the synthesis of this component may be present on other chromosomes, very likely 6A and 6B, since the analysis of the ‘Chinese Spring’ compensating nullisomic-tetrasomics involving the 6D chromosome does not show the loss of this component or any apparent change in staining intensity. Chromosomal location data and two-dimensional gliadin maps reveal close homologies between the two hexaploid wheats, ‘Chinese Spring’ (T. aestivum ssp. vulgare) and T. aestivum ssp. spelta, belonging to different subspecies in the hexaploid group of genomic formula AABBDD. The comparison of gliadin electrophoretic patterns aiding in the identification of evolutionary pathways in wheat is stressed.
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  • 29
    ISSN: 1432-2242
    Schlagwort(e): Lotus corniculatus ; Lotus tenuis ; 2n gametes ; Evolution ; Breeding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Crosses between male sterile L. corniculatus (2n=4x=24) and L. tenuis (2n=2x=12) plants were performed in order to verify the presence of 2n gametes in L. tenuis. All but one of the plants from these crosses had 2n=4x=24 and the L. corniculatus phenotype; this plant had 2n=2x=12 and the L. tenuis phenotype. The plants also showed good quantity of pollen at tripping, good pollen fertility and good percentage of seed setting in the backcross to L. corniculatus. On the whole, both cytological and morphological observations, showing that all but one of the plants from L. corniculatus x L. tenuis were normal tetraploids, suggest the existence of diploandrous gametes in L. tenuis. On the other hand, haploid parthenogenesis probably gave origin to the dihaploid plant 2n=2x=12.
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 77 (1989), S. 689-700 
    ISSN: 1432-2242
    Schlagwort(e): Triticum ; Homoeoalleles ; Evolution ; Dough ; Gene library
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Two high-molecular-weight subunit (HMWS) glutenin genes from the A and B genomes of the hexaploid bread wheat Triticum aestivum L. cv Cheyenne have been isolated and sequenced. Both of these genes are of the high Mr class (x-type) of HMW glutenins, and have not been previously reported. The entire set of six HMW genes from cultivar Cheyenne have now been isolated and characterized. An analysis of the Ax and Bx sequences shows that the Ax sequence is similar to the homoeologous gene from the D genome, while the Bx repeat structure is significantly different. The repetitive region of these proteins can be modelled as a series of interspersed copies of repeat modifs of 6, 9, and 15 amino acid residues. The evolution of these genes includes single-base substitutions over the entire coding region, plus insertion/deletions of single or blocks of repeats in the central repetitive domain.
    Materialart: Digitale Medien
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  • 31
    ISSN: 1617-4623
    Schlagwort(e): Cyanobacteria ; Evolution ; Thylakoid ; Leader sequence ; Photosystem II
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A 9 kDa polypeptide which is loosely attached to the inner surface of the thylakoid membrane and is important for the oxygen-evolving activity of Photosystem II in the thermophilic cyanobacterium Phormidium laminosum has been purified, a partial amino acid sequence obtained and its gene cloned and sequenced. The derived amino acid sequence indicates that the 9 kDa polypeptide is initially synthesised with an N-terminal leader sequence of 44 amino acids to direct it across the thylakoid membrane. The leader sequence consists of a positively charged N-terminal region, a long hydrophobic region and a typical cleavage site. These features have analogous counterparts in the “thylakoid-transfer domain” of lumenal polypeptides from chloroplasts of higher plants. These findings support the view of the proposed function of this domain in the two-stage processing model for import of lumenal, nuclear-encoded polypeptides. In addition, there is striking primary sequence homology between the leader sequences of the 9 kDa polypeptide and those of alkaline phosphatase (from the periplasmic space of Escherichia coli) and, particularly in the region of the cleavage site, the 16 kDa polypeptide of the oxygen-evolving apparatus in the thylakoid lumen of spinach chloroplasts.
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 218 (1989), S. 323-329 
    ISSN: 1617-4623
    Schlagwort(e): Mutagenic DNA repair ; Evolution ; Murray collection ; impCAB
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Resistance transfer factors are natural conjugative plasmids encoding antibiotic resistance. Some also encode mutagenic DNA repair genes giving resistance to DNA damage and induced mutagenesis. It has been shown that antibiotic resistance has been acquired by recent transposition events; however, we show here that mutagenic repair genes existed much earlier on these types of plasmids. Conjugative plasmids from eight incompatibility groups from the Murray collection of ‘pre-antibiotic era’ enterobacteria were tested for complementation of mutagenic repair-deficient Escherichia coli umuC36. Although none of these plasmids carry transposon-encoded drug resistance genes, IncI1 and IncB plasmids were identified which restored ultraviolet resistance and induced mutability to umuC36 mutants. Furthermore they increased the UV resistance and induced mutability of wild-type E. coli, Klebsiella aerogenes and Citrobacter intermedius, thus showing that they could confer a general selective advantage to a variety of hosts. Like know mutagenic repair genes, complementation by these plasmid genes required the SOS response of the host cell. Nucleotide hybridisation showed that these plasmids harboured sequences similar to the impCAB locus, the mutagenic repair operon of modern-day IncI1 plasmids. The evolution of mutagenic repair genes is discussed.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Biology and philosophy 4 (1989), S. 255-273 
    ISSN: 1572-8404
    Schlagwort(e): Natural Selection ; Evolution ; Principle ; Probability ; Propensity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Abstract The theory of natural selection is a rich systematization of biological knowledge without a first principle. When formulations of a proposed principle of natural selection are examined carefully, each is seen to be exhaustively analyzable into a proposition about sources of fitness and a proposition about consequences of fitness. But whenever the fitness of an organic variety is well defined in a given biological situation, its sources are local contingencies together with the background of laws from disciplines other than the theory of natural selection; and the consequences of fitness for the long range fate of organic varieties are essentially applications of probability theory. Hence there is no role and no need for a principle of the theory of natural selection, and any generalities that may hold in that theory are derivative rather than fundamental.
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Biology and philosophy 4 (1989), S. 287-301 
    ISSN: 1572-8404
    Schlagwort(e): Evolution ; Incest Taboo ; Ethics ; Behavioral Development
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Abstract Human propensities that are the products of Darwinian evolution may combine to generate a form of social behavior that is not itself a direct result of such pressure. This possibility may provide a satisfying explanation for the origin of socially transmitted rules such as the incest taboo. Similarly, the regulatory processes of development that generated adaptations to the environment in the circumstances in which they evolved can produce surprising and sometimes maladaptive consequences for the individual in modern conditions. These combinatorial aspects of social and developmental dynamics leave a subtle but not wholly uninteresting role for evolutionary biology in explaining the origins of human morality.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Biology and philosophy 4 (1989), S. 457-481 
    ISSN: 1572-8404
    Schlagwort(e): Evolution ; evolutionary biology ; fitness ; decision theory ; theory of choice ; rationality ; rational behavior ; reductionism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Abstract A fundamental philosophical question that arises in connection with evolutionary theory is whether the fittest patterns of behavior are always the most rational. Are fitness and rationality fully compatible? When behavioral rationality is characterized formally as in classical decision theory, the question becomes mathematically meaningful and can be explored systematically by investigating whether the optimally fit behavior predicted by evolutionary process models is decision-theoretically coherent. Upon investigation, it appears that in nontrivial evolutionary models the expected behavior is not always in accord with the norms of the standard theory of decision as ordinarily applied. Many classically irrational acts, e.g. betting on the occurrence of one event in the knowledge that the probabilities favor another, can under certain circumstances constitute adaptive behavior. One interesting interpretation of this clash is that the criterion of rationality offered by classical decision theory is simply incorrect (or at least incomplete) as it stands, and that evolutionary theory should be called upon to provide a more generally applicable theory of rationality. Such a program, should it prove feasible, would amount to the logical reduction of the theory of rational choice to evolutionary theory.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied phycology 1 (1989), S. 59-65 
    ISSN: 1573-5176
    Schlagwort(e): temperature ; acclimation ; Eucheuma alvarezii ; Eucheuma isiforme
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Branch cultures ofEucheuma alvarezii Doty var.tambalang Doty, farmed in the Philippines, andE. isiforme (C. Agardh) J. Agardh var.denudatum Cheney, from the west coast of Florida, were gradually transferred through three temperature regimes over a 6-week period. Photosynthetic responses were measured under a series of irradiances (P-I curves) and temperatures to determine immediate responses of the plants before, during and after completion of the transfers. The Philippine variety did not show acclimation to 18 °C either after gradual transfer from the initial culture temperature of 25 °C or when abruptly transferred from 25 to 18 °C. The Florida variety did show acclimation to 25 °C when gradually transferred from 18 to 22 to 25 °C over the 6-week period, but not if abruptly transferred from 18 to 25 °C. The west coast variety ofE. isiforme from Florida shows a temperature acclimation ability that parallels the seasonal changes in water temperature of its habitat.
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 119 (1989), S. 87-97 
    ISSN: 1573-5036
    Schlagwort(e): irradiance ; root development ; root growth ; shoot development ; shoot growth ; temperature ; thermal time ; winter wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Wheat plants were grown in columns of soil until early stem elongation at a wide range of constant root temperatures. Two light environments were imposed and three levels of nitrogen fertilizer added at sowing. Shoot and root development and growth were measured by destructive sampling to investigate the combined effects of temperature and changing nutrient and assimilate supply. Both mainstem leaf and root axis production were linearly related to thermal time above a base temperature of 0°C. Low irradiance affected the appearance of mainstem tillers and associated nodal root axes. Nitrogen had little effect on shoot or root development but increased shoot area between 6 and 8 mainstem leaves. Higher temperatures and supplementary light resulted in larger root systems when compared at equivalent times after sowing. Total root length and root dry weight increased exponentially with thermal time, based on the mean of 4 cm soil and 2 cm air temperatures, but no single relation existed for all temperature and light treatments. Total plant dry matter, root length and root dry weight increased linearly with accumulated, intercepted, photosynthetically active radiation. Root growth responded less than the shoot to supplementary light. Increasing temperature reduced the proportion of root weight to total plant weight.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 119 (1989), S. 99-110 
    ISSN: 1573-5036
    Schlagwort(e): Irradiance ; root development ; root growth ; temperature ; thermal time ; winter wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Winter wheat was sown on 2 dates with 3 levels of nitrogen fiertiliser (0, 50 and 200 kg N ha−1) in one year and on 2 sites in a followign season. Shoot and root development and growth were measured between emergence and anthesis in the first season and emergence and 7 mainstem leaves in the second. Differences in temperature and light regime led to significant differences in shoot and root development and growth between sowing dates. A thermal time-scale, based on soil surface or air temperatures, with a base of 0°C, adequately described the production of mainstem leaves and nodal root axes over all treatments. Autumn applied nitrogen had little effect on development. Shoot growth and green area index increased exponentially with thermal time prior to spring nitrogen application and the completion of canopy development. Early-sown crops had larger root systems than late-sown crops prior to winter and this divergence was retained until anthesis. The relationship between root growth and thermal time was little better than with days after sowing and was not improved by either varying the site of temperature measurement or the base temperature used for calculation. Differences in soil texture and drainage, between sites, led to significant changes in root length distribution. Although spring applied nitrogen generally increased root length, its effects were inconsistent. There was a curvilinear relation between root length and the amount of photosynthetically active radiation (PAR) intercepted; this relation was unaffected by sowing date or nitrogen treatment. The amount of root produced per unit PAR decreased as the season progressed, reflecting the decrease in the proportion of total dry matter partitioned to the root system.
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Primates 30 (1989), S. 95-102 
    ISSN: 0032-8332
    Schlagwort(e): Macaques ; Hemoglobin ; Duplication hypothesis ; Evolution ; Isoelectric focusing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Blood samples were collected fromMacaca fascicularis andMacaca mulatta living in indoor breeding groups and investigated electrophoretically. Hemoglobin polymorphism was observed in both species. Isoelectric focusing was performed on urea denaturated samples to test the hypothesis of a site duplication at theα-chain locus inM. fascicularis (Barnicot et al., 1970). The results of our investigations do not support the above mentioned hypothesis. Only one locus coding theα-chain was detected, and this is under the control of two alleles. Evolutionary events at the molecular level are discussed, as well asWheatley's hypothesis (1980) that malaria was an important force behind divergence in both species. InM. fascicularis hemoglobin variants might be similarily connected with malaria resistance as in man. We suggest that this was not an important process behind speciation in macaques.
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 219 (1989), S. 199-203 
    ISSN: 1617-4623
    Schlagwort(e): Sequence rearrangement ; Gene localization ; Restriction analysis ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The chloroplast DNAs of Acetabularia mediterranea strains 5 and 17 differ significantly in their restriction patterns. Southern blotting analysis using gene probes derived from the coding regions of spinach genes showed that psbB and petB each map to unique restriction fragments which are shared in strains 5 and 17. On the other hand psaA, psbA and rbcL map to different restriction fragments in strains 5 and 17 probably as a result of restriction fragment length polymorphism. In addition to restriction fragment polymorphism there is evidence for much larger differences in the organization of the plastome. The most striking difference is the absence in strain 5 of a 10 kb repeated sequence which has previously been demonstrated in strain 17. However, both strains apparently share at least 8 kb of the 10 kb repeated sequence. Restriction analysis of independent clones of the 10 kb sequence revealed a family of non-identical repeats.
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  • 41
    ISSN: 1617-4623
    Schlagwort(e): Maltose transport ; malB region ; Positive regulation ; Palindromic units ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The malE and malK genes from Salmonella typhimurium, and the MalEFG operon and a portion of malK from Enterobacter aerogenes were cloned and sequenced. Plasmid-borne malE genes from both species and the malF and malG genes from E. aerogenes were expressed normally in Escherichia coli, and their products function in maltose transport. This shows that the malB products from the three species are interchangeable, at least in the combinations tested. The general genetic organization of the malB region is conserved. Potential binding sites and distances between them are highly conserved in the regulatory intervals. An unexpected conserved region was detected, which we call the U box, and which could be another target for a regulatory protein. This hypothesis is supported by the presence of the U box in the regulatory, region of the pulA-malX operon in Klebsiella pneumoniae. The intergenic region between malE and malF from S. typhimurium and E. aerogenes, contains inverted repeats similar to the palindromic units (PU or REP) found at the same location in E. coli. The predicted amino acid sequence of the encoded proteins showed 90% or more identity in every pairwise comparison of species.
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 41 (1989), S. 65-69 
    ISSN: 1573-5060
    Schlagwort(e): Fragaria ; Potentilla ; intergeneric hybrids ; pollen storage ; temperature ; relative humidity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Low temperature and humidity were used for the storage of pollen of four species of Fragaria (2n=14, 42 and 56) and two species of Potentilla (2n=14). The stainability of Fragaria pollen was assessed over a number of years by use of aceto-carmine stain and its viability by cross-pollinations; stainability of Potentilla pollen was assessed by acetocarmine. Fragaria pollen so stored remained stainable for seven years and showed the ability to set seed for three years. over the latter period, aceto-carmine staining gave a reasonable prediction of seed set produced by the stored pollen of Fragaria and so is of value in estimating pollen viability in that genus. Potentilla pollen remained stainable for three years.
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Photosynthesis research 21 (1989), S. 17-26 
    ISSN: 1573-5079
    Schlagwort(e): chlorophyll fluorescence ; herbicide binding ; photoinhibition ; photosynthesis ; photosystem II ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The time courses of some Photosystem II (PS II) parameters have been monitored during in-vivo and in-vitro photoinhibition of spinach chloroplasts, at room temperature and at 10 °C or 0 °C. Exposing leaf discs of low-light grown spinach at 25 °C to high light led to photoinhibition of chloroplasts in-vivo as manifested by a parallel decrease in the number of functional PS II centres, the variable chlorophyll fluorescence at 77K (F v /F m ), and the number of atrazine-binding sites. When the photoinhibitory treatment was given at 10 °C, the former two parameters declined in parallel but the loss of atrazine-binding sites occurred more slowly and to a lesser extent. During in-vitro photoinhibition of chloroplast thylakoids at 25 °C, the loss of functional PS II centres proceeded slightly more rapidly than the loss of atrazine-binding sites, and this difference in rate was further increased when the thylakoids were photoinhibited at 0 °C. During the recovery phase of leaf discs (up to 9 h) the increases in F v /F m preceded that of the number of functional PS II centres, while only a further decline in the number of atrazine-binding sites was observed. The recovery of variable chlorophyll fluorescence and the concentration of functional PS II centres occurred more rapidly at 25 °C than at 10 °C. These results suggest that the photoinhibition of PS II function is a relatively temperature-independent early photochemical event, whereas the changes in the concentration of herbicide-binding sites appear to be a more complex biochemical process which can occur with a delayed time course.
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 40 (1989), S. 121-126 
    ISSN: 1573-5060
    Schlagwort(e): Chrysanthemum morifolium ; chrysanthemum ; tolerance ; temperature ; days to flower ; breeding ; component analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Twenty seven clones of chrysanthemum, 19 of which were selected at low temperature, were flowered at 10, 14, 18 and 22°C. The number of days to flower in response to temperature could, for each genotype, be described by a parabola with the parameters: optimum temperature, days to flower at the optimum temperature and curvature which represents the sensitivity to temperature. The low-temperature selections did not have a reduced optimum temperature but reduced sensitivity to temperature accounted for most of the ability to flower at low temperature. The parameters may vary independently. Examples are given to show how these parameters can be combined to construct genotypes with a required temperature response.
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  • 45
    ISSN: 1573-5117
    Schlagwort(e): Acanthocyclops ; productivity ; temperature ; food limitation ; generation time
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The generation time of the predatory cyclopoid copepod Acanthocyclops robustus was estimated on 11 occasions during the years 1980 to 1982 in Alderfen Broad. In a multiple regression model, generation time was found to be uncorrelated with temperature, positively correlated (p 〈 0.05) with the densities of Bosmina longirostris and rotifers, and negatively correlated (p 〈 0.001) with the density of nauplii of the calanoid copepod Eudiaptomus gracilis. It is suggested that generation time was determined largely by the availability of calanoid nauplii as prey, even though these constituted only 2% of zooplankton standing biomass.
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 184 (1989), S. 79-88 
    ISSN: 1573-5117
    Schlagwort(e): Cyclopoid copepods ; development times ; eggs ; instars ; temperature ; diapause
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The duration times of eggs, combined naupliar instars and of the different copepodite stages of five species of cyclopoid copepods — Acanthocyclops robustus, Cyclops vicinus, Diacyclops bicuspidatus, Mesocyclops leuckarti, and Thermocyclops crassus — were investigated at five different temperatures. The five species can be divided in two groups: two species, C. vicinus and D. bicuspidatus, adapted to cold water conditions and three species, A. robustus, M. leuckarti and T. crassus adapted to warm water conditions. The cold water species showed a faster egg development than M. leuckarti and T. crassus at 5–15 °C. The eggs and instars of the warm water species M. leuckarti tend to develop faster than those of the former two species at higher temperatures. A. robustus showed the shortest egg and instar development at 10–25 °C. The warm water species T. crassus produced no eggs at 10 °C and temperatures below. At higher temperatures (20, 25 °C) the egg and instar duration times were similar or longer than those of the other species. When cultured in total darkness a great part of the CIV respectively CV copepodites of the summer forms entered arrest and the percentage of copepodites that showed an arrest of development was highest at lowest temperatures. The present results are compared with data from literature and differences are discussed.
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 186-187 (1989), S. 81-102 
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; rate of population increase ; life span ; temperature ; salinity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A review of temperature and salinity effects on rotifer population dynamics is presented together with original data of these effects for three clones of Brachionus plicatilis. There is a clear relationship between temperature and the intrinsic rate of increase, r: an increase of temperature — within the natural environmental range — produces an exponential increase of r, and the slope of the response depends on the genotype. The effect of salinity is also genetically dependent; the highest r for each clone is observed at the salinity close to that of its environmental origin. The response of r to temperature is mainly a consequence of the response of the individual rates of development and reproductive timing. The effect of temperature on fecundity (number of descendents per individual life time) is negligible when temperature values are within the normal habitat ranges. On the other hand, salinity seems to affect primarily fecundity. The interaction salinity-temperature may be important in clones or species living in fluctuating environments with positive response to the more frequent combinations found in the corresponding habitats.
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 186-187 (1989), S. 129-136 
    ISSN: 1573-5117
    Schlagwort(e): Hexarthra ; salinity ; alkalinity ; wind action ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In Neusiedler See, a shallow alkaline lake with fluctuating water level and salinity, four species of Hexarthra occur: H. mira, H. fennica, H. jenkinae (occasional) and H. polyodonta. The analysis of longterm data reveals a general phenological pattern which does not change from year to year. They first occur in May, develop a maximum in June/July, sometimes a second one in August/September and disappear in October. But the species succession is different in the various years, occasionally only one species (H. mira or H. polyodonta) being present. There is a fairly consistent relation between the chemical conditions and the prevalent species; an increase in salinity favours the development of H. polyodonta. Low temperature and wind generated suspended particles have a negative influence on the development of the Hexarthra populations. Smaller populations of Hexarthra are in a relation to the occurrence of Leptodora indicating predation pressure of the latter species. In Neusiedler See the Hexarthra populations seem to be controlled to a great extent by abiotic factors, but predation by Leptodora and most probably by young fish seems to play an important role too.
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  • 49
    ISSN: 1573-5117
    Schlagwort(e): Rotifera ; resting eggs ; light ; temperature ; hatching ; mixis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The marine rotifer Brachionus plicatilis typicus (Clone 8105A, Univ. of Tokyo) was cultured in 500 ml beakers to form resting eggs. Tetraselmis tetrathele was used as a culture food. Just after formation, resting eggs were exposed to various temperature (5–25 °C) and light regimes (24L: OD and OL : 24D). When eggs were exposed to light just after formation, the eggs hatched sporadically over a month. No hatching was observed for six months when eggs were preserved under dark conditions regardless of the temperature. These eggs hatched simultaneously after being exposed to light and eggs preserved at 5 °C showed twice as high hatching rate (40%) as that of eggs preserved at 15–25 °C (24%). Clones from resting eggs that were kept under different temperature and light regimes were reared individually to the third generation. Incubation at 25 °C with lighting produced the highest (5.4% and 5.2 %) rate of mictic females during their 2nd and 3rd generations, respectively. The lowest rates (0 and 1.5%) were found when the eggs were kept at 5 °C in total darkness for six months. A lower rate of amictic female production was found in clones with higher rates of mixis.
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 186-187 (1989), S. 209-214 
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; distribution ; temperature ; oxygen content
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Lunzer Obersee, a small lake located at an altitude of 1100 m above sea level, was investigated from July 1985 to October 1987. The rotifer community consists of 7 dominant species, 7 subdominant species and 34 species which occasionally occurred in the plankton. The dominant species show rather different demands in relation to temperature and oxygen content; e.g.: Filinia hofmanni was found at a wide range of oxygen concentrations (0.6–13.3 mg O2l−1) and low temperatures (4–6 °O, living in the upper water layers (1–7 m) during spring and in the deeper, anoxic zone in summer. In contrast, Asplanchna priodonta was found at rather high oxygen contents (〉 9 mg O2 l−1), ), and showed a wide range of temperature tolerance (4–15 °C). On the basis of field data the temperature and oxygen requirements of several species are described and discussed.
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 186-187 (1989), S. 363-369 
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; temperature ; food concentration ; bioenergetic parameters
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The influence of temperature and food quality was studied on the following energy balance parameters of B. angularis: ingestion, production, growth and mortality. The ingestion rate rises to an optimum at 15 and 20 °C and decreases at 25 °C. The other rates increase continuously over the 5–25 °C range. The Q10-values of production rate are higher than those of ingestion rate. Temperature also modifies the relationship between food concentration and bioenergetic rates. They react according to a Monod function (production at all temperatures, growth at 10 °C) or decrease at high concentrations (growth at 15° and 20 °C.)
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 186-187 (1989), S. 381-386 
    ISSN: 1573-5117
    Schlagwort(e): biometric analysis ; resting eggs ; rotifers ; salinity ; temperature ; genetic variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of temperature and salinity on resting egg size of two Brachionus plicatilis (Rotifers) clones was investigated. Clones were selected according to their different behaviour in laying resting eggs: one clone ejects them, whereas they remain inside the females body in the other clone. The difference in resting eggs size between the two clones is noticeable, although the difference is not as great as that between female body size. An important temperature-salinity interaction on resting egg size has been observed. The general inverse relationship between size and temperature is only true at lower temperatures. At high temperatures size varies around the mean although could be greater than at intermediate temperatures. This is more evident at the intermediate salinity tested which is considered to be the closest to the optimum in our experiments. This pattern of variation suggests that mean size is bigger than expected, in relation to temperature and salinity, when these factors have values close to the extremes of their range, normally found in nature, and to which adaptative mechanisms can evolve. Size is bigger at the salinity — temperature low - low and high - high combinations which are the most commonly found in the temperate environments.
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 172 (1989), S. 39-49 
    ISSN: 1573-5117
    Schlagwort(e): Antarctica ; bacteria ; biofilms ; cyanobacteria ; microbial mats ; Nostoc ; Phormidium ; photosynthesis ; respiration ; stream algae ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Water temperatures in southern Victoria Land streams fluctuated over the range 0 to 10 lay close to freezing. In a series of controlled assays at Fryxell Stream, Taylor Valley, the benthic microbial mats showed strongly positive metabolic responses to increases in temperature well above ambient. Rates of polysaccharide and lipid biosynthesis increased with temperature over the range 0 to 25 °C. Between 0 and 10 °C, Q10 values for the cyanobacterial mats were 1.7 to 3.2 for gross photosynthesis, 2.5 to 5.7 for respiration, 2.2 to 2.5 for acetate incorporation into lipid, 1.9 to 3.8 for glucose catabolism, and 1.9 to 2.8 for thymidine incorporation. Respiration accounted for a high percentage of gross photosynthesis, and a net respiratory loss of carbon from three communities was either induced or worsened by an increase in temperature from 0 to 10 °C. The chlorophyll a content of Nostoc disc incubated for one month in darkness decreased by 27% at 5 °C, but by 99% at 25 °C. This set of assays suggests that the cyanobacterial mats contained large amounts of chlorophyll a and carbon associated with inactive or senescing cells. This unusual standing stock could probably not persist under warmer conditions, which would promote both increased respiratory losses and faster rates of bacterial decomposition.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 173 (1989), S. 219-229 
    ISSN: 1573-5117
    Schlagwort(e): aquatic fungi ; temperature ; seasonal periodicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The occurrence, distribution and seasonal periodicity of 49 species of aquatic fungi belonging to the orders Chytridiales, Lagenidiales, Blastocladiales, Saprolegniales and Peronosporales from two tanks of Kurukshetra, India, is described. Seasonal periodicity was found to be governed by temperature.
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 174 (1989), S. 89-97 
    ISSN: 1573-5117
    Schlagwort(e): carbon ; Illinois ; light ; nitrate ; nutrient limitation ; periphyton ; phosphate ; streams ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Factors limiting periphyton accrual in east-central Illinois agricultural streams were investigated. Nutrient-diffusing substrata were used to examine periphyton macronutrient limitation in streams in two agricultural watersheds. Substrata consisted of sand-agar mixtures with one of six experimental treatments. Macronutrients included carbon, nitrate, phosphate and combinations of the three. Substrata were collected after a 5 and 9 day period and analyzed for chlorophyll a. None of the treatments were significantly greater than the controls at any of the seven stations, thus we conclude that periphyton in these streams was not nutrient limited. Highest periphyton colonization/growth rates were associated with the smaller upstream reaches, while lower rates occurred in the larger downstream reaches. Multiple regression showed that most of the variance in the rate of chlorophyll a accrual after five days was explained through water temperature and turbidity (r2 = 0.91); whereas, stream nitrate and phosphate concentrations accounted for no significant portion of the variance. We conclude that instream primary production in agricultural streams of central Illinois is limited by temperature and light.
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 179 (1989), S. 17-24 
    ISSN: 1573-5117
    Schlagwort(e): profiles ; resolution ; monitoring ; temperature ; oxygen ; spate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Longitudinal profiles of water quality along a well-mixed tidal river are, ideally, based on simultaneous measurements at fixed stations distributed along the river. The resolution of the profiles is limited by the density of the stations. However, for a given number of stations the resolution is greatly increased if water quality date can be extrapolated upstream and downstream of the stations, making use of velocity data; the resolution is then determined by the density of the extrapolated data points, which may be an order of magnitude higher than the density of the stations. A 15-km length of river was investigated using 5 current meters equipped to measure depth, temperature, conductivity and dissolved oxygen. Data were recorded simultaneously every 10 minutes. When the average cross-sectional speed was 0.25 ms−1 (typical of tidal conditions), the extrapolated data points were 150 m apart, so the resolution of the resulting profiles (7 per kilometre) was much higher than that of the stations alone (0.3 per kilometre). The extrapolation process required a means of deducing the average cross-sectional speed from the speed measured at a given station. The key to this was provided by temperature data recorded during the onset of a spate, when tidal flow was suspended and the average cross-sectional speed was uniformly about 0.75 ms −1 at four of the stations. Profiles of temperature and dissolved oxygen were generated by this method; the resolution was about 2 data points km−1 during the onset of the spate, and 6 points km−1 during tidal flow.
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 175 (1989), S. 223-231 
    ISSN: 1573-5117
    Schlagwort(e): Rotifera ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Information on the distribution of 225 species of planktic, periphytic and benthic rotifers from diverse waters in south and central Sweden was analyzed for temperature preference and tolerance. Most rotifers have a very wide tolerance range. Certainly differences in temperature dependence exist between separate species. However, these differences are, in a regional material like this, generally less distinct than what has been found for the distribution within individual lakes.
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Environmental biology of fishes 24 (1989), S. 199-218 
    ISSN: 1573-5133
    Schlagwort(e): Blenniidae ; Chaenopsidae ; Evolution ; Generalization ; Labrisomidae ; Morphological series ; Oral jaw apparatus ; Specialization ; Tripterygiidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Synopsis The ecomorphological relationships between the oral jaws and food spectra were highlighted in 34 species of Gulf of California blennioid fishes (5 Tripterygiidae, 13 Labrisomidae, 11 Chaenopsidae and 5 Blenniidae). Twenty-nine species are microcarnivorous, two are omnivorous browsers, two are algae grazers and one was an ‘ectoparasite’ feeder. The spectrum of oral (as opposed to pharyngeal) jaw (OJA) morphology ranges from plesiomorphic, suction-feeding (relatively large, protrusible jaws, with many coniform-caniniform teeth) to apomorphic, biting (relatively small, non protrusible jaws, with a single row of incisiform teeth). As species with similar morphology may widely differ in food, it is concluded, that morphology is not a reliable predictor for ecology in this case. With the exception of a few specialists, species with apomorphic, biting OJA utilize sessile items in addition to mobile categories and thus show a higher food diversity as compared to species with plesiomorphic OJA. Thus in the present case morphological differentiation goes along with ecological generalization. Only three blenniid species with the most apomorphic OJA may be considered as specialized also with regard to food resource utilization. Transformation of morphological characters and the ecological role of the OJA of blennioids may serve as a model to illustrate the steps required to achieve a biting-browsing and grazing feeding apparatus in many taxa of modern acanthopterygian reef fishes.
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 116 (1989), S. 69-76 
    ISSN: 1573-5036
    Schlagwort(e): oxidation ; soil ; sulphur ; temperature ; tetrathionate ; thiosulphate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The rate of oxidation of micronized elemental sulphur in three soils was measured over a range of temperatures between 2 and 20°C. Temperature had a marked effect with a Q10 (temperature coefficient) between 1.9–3.1. The period for 50% oxidation varied between 6–10 days at 20°C to between 36–42 days at 2°C. All the oxidation curves showed an initial lag. At 20°C the oxidation rate was four times that of flowers of sulphur and was related to the smaller particle size. Additives (wetting and dispersing agents) in the commercial micronized sulphur preparation used (‘Thiovit’) were inhibitory at high concentrations but stimulatory at low concentrations. The significance to field conditions is discussed.
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 18 (1989), S. 167-179 
    ISSN: 1573-5044
    Schlagwort(e): Vicia faba L. ; in vitro propagation ; temperature ; nitrogen ; activated charcoal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The influences of nitrogen sources, culture temperature and activated charcoal supplements were studied in relation to the rooting ability of V. faba cuttings. The interaction of these factors led to quantitative and qualitative modifications of the culture responses. Low temperatures (14–18°C) were suitable for in vitro culture, limiting the formation of phenolics in plant material and making activated charcoal supplement unnecessary. Nitrogen supplements contributed in modifying the different plant responses, in accordance with temperature. Multiple shoot formation was obtained from the cotyledonary node and from the stem nodes cultivated in the presence of 6-benzylaminopurine (BAP). BAP at 4 mg l-1 was the most effective concentration in promoting high rates of shoot development. The original position of stem nodes was found to determine the explant response to plant growth regulator treatments, possibly due to the effect of residual apical dominance.
    Materialart: Digitale Medien
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Journal of bioenergetics and biomembranes 21 (1989), S. 115-135 
    ISSN: 1573-6881
    Schlagwort(e): Membrane fluidity ; fish membranes ; homeoviscous adaptation ; temperature ; hydrostatic pressure ; acclimation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Physik
    Notizen: Abstract The homoeostatic regulation of bilayer order is a property of functional importance. Arguably, it is best studied in those organisms which experience and must overcome disturbances in bilayer order which may be imposed by variations in temperature of hydrostatic pressure. This article reviews our recent work on the adaptations of order in brain membranes of those fish which acclimate to seasonal changes in temperature or which have evolved in extreme thermal or abyssal habitats. The effects of temperature and pressure upon hydrocarbon order and phase state are reviewed to indicate the magnitude of the disturbances experienced by animals in their environments over the seasonal or evolutionary timescale. Acclimation of fish to altered temperature leads to a partial correction of order, while comparison of fish from extreme cold environments with those from temperate or tropical waters reveals a more complete adaptation. Fish from the deep sea also display adaptations of bilayer order which largely overcome the ordering effects of pressure.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Journal of biological physics 17 (1989), S. 109-125 
    ISSN: 1573-0689
    Schlagwort(e): Evolution ; order ; complexity ; biological systems
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Physik
    Notizen: Abstract In this, Part III of a general theory, the large-scale features of evolution of structure, order, and complexity are considered as characteristic features of the biological state of matter. This starts with a rigorous formal definition of structure, classes of structural order, complexity, measures of complexity, and how these arise through evolution by a cumulative process of storing information in memory systems. Three such memory systems have evolved: the genetic memory, the immune memory, and the memories of the nervous system. The evolution, characteristic parameters and the limitations of these memory systems are explored. From these considerations emerge the large-scale features of the evolutionary pathways of biological structure, function, and complexity.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 63
    ISSN: 1573-5087
    Schlagwort(e): Abscisic acid ; dormancy ; batatasin-I ; phthalic acid ; temperature ; Dioscorea floribunda
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In the tubers of medicinal yam (Dioscorea floribunda Mart. & Gal.) abscisic acid (ABA) content was high in all the parts during the dormant condition in the winter, but it decreased to a very low level in the actively growing plants. ABA content of the entire tuber was negatively correlated with temperature and photoperiod. Growth inhibitors including batatasin-I and phthalic acid were identified in the dormant tuber.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Environmental biology of fishes 25 (1989), S. 159-170 
    ISSN: 1573-5133
    Schlagwort(e): Jaws ; Evolution ; Corals ; Teeth ; Cladistics ; Specialists
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Synopsis The jaw dentition of fifteen species of Pacific and Western Atlantic chaetodontid butterflyfishes was examined in light of their feeding habits and phylogenetic relationships. The ancestral tooth pattern is typical of many of the butterflyfishes, and variations on this basic pattern involve changes in the arrangement, length and number of teeth, and tooth shape to a lesser extent. Many of the more derived conditions can be explained by simple changes in relative jaw shape and size. Despite what appears to be adequate time for evolutionary changes to occur between the Pacific and Western Atlantic faunas, many species retain the generalized tooth arrangement permitting efficient exploitation in a very generalized manner. However, Pacific species as a whole show more specialized morphologies for hard coral feeding than do Western Atlantic species. Cases of parallel and divergent evolution are identified between and among the two faunas. Most morphological change associated with feeding in butterflyfishes is confined to the anterior region of the head, and particularly a few key elements. Suggestions for future morphological studies on the chaetodontids are outlined.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Journal of comparative physiology 159 (1989), S. 139-151 
    ISSN: 1432-136X
    Schlagwort(e): Calliphorin ; Hemocyanin ; Monoclonal antibodies ; Evolution ; Spiders
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Three murine hybridoma cell lines secreting IgG1 antibodies to 4×6 tarantula (Eurypelma californicum) hemocyanin were isolated, and the monoclonal antibodies Ec-7, Ec-8 and Ec-24 characterized by immunoblotting, immunoelectrophoresis and ELISA. WholeEurypelma hemocyanin, and the isolated subunitsa tog served as probes. For the subunits a novel, quick purification scheme on FPLC combined with immuno-affinity chromatography was established. Additionally, two cell lines secreting IgM antibodies were isolated. These antibodies showed irrelevant cross reactivities. Ec-7 strongly reacts with subunitd and weakly withb. Ec-8 and Ec-24 are specifically directed againstEurypelma subunitsa ande, respectively. The epitopes of Ec-7 and Ec-8 are sequence-dependent, whereas the Ec-24 epitope is conformation-dependent. Ec-8 and Ec-24 are specific forEurypelma hemocyanin. Ec-7 is not reactive to crustacean, centipede or gastropod hemocyanins, but binds to scorpion hemocyanin and to the immunological correlates of subunitsd andf in the hemocyanins of the spiderCupiennius salei and the xiphosuranLimulus polyphemus. In immunoblots with different polyclonal antisera,Eurypelma andAstacus hemocyanin cross-reacted with calliphorin, a larval serum protein from the blowflyCalliphora vicina. Calliphorin and chelicerate hemocyanins share the Ec-7 epitope. Sedimentation coefficients, pH stability regions, subunit size, and electron microscopical appearance of calliphorin are indiscernable from a typical 1×6 arthropod hemocyanin. This relationship is discussed in the context of hemocyanin evolution.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Human evolution 4 (1989), S. 63-71 
    ISSN: 1824-310X
    Schlagwort(e): Snub-nosed monkey ; Myology ; Evolution ; Functional anatomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Some differences between the muscular system of three species of golden monkeys were shown. The major features of the myology in these animals, besides that ofCercopithecoidea, are similar to the anthropoid apes and humans. Although most of the features between taxa of golden monkeys are largely homologous, there are also some differences. Our results differ slightly from thosePatterson (1942) obtained inR. roxellanae. Some conclusions reported by Patterson were obviously incorrect, since the specimen he used did not have a head. Many mylogical characters are similar to other species ofCercopithecoidea while some resemble those of apes. Many are similar to those of the leaf monkey, though some of them show much more development. The golden monkey is more advanced than any other species ofCercopithecoidea. We hypothesize that in terms of the myological characters the golden monkeys seem to occupy a position between the leaf monkeys and the apes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Primates 30 (1989), S. 403-422 
    ISSN: 0032-8332
    Schlagwort(e): Evolution ; Polymorphism ; Phylogeny ; Genetic markers ; Cercopithecinae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Serum proteins and RBC enzymes were surveyed in 16 species (183 animals) of African guenons (tribe Cercopithecini) in order to determine their genetic polymorphism and to establish dendrograms on the basis of their allele frequencies. The molecular data obtained were compared with those of mangabeys (16 animals tested) and discussed in the light of our results inPapio andMacaca. The species surveyed wereCercopithecus neglectus, C. hamlyni, C. l'hoesti (C. l'h. l'hoesti, C. l'h. preussi, andC. l'h. solatus), C. nictitans, C. mitis (C. m. kolbi, C. m. albotorquatus, C. m. stuhlmanni, andC. m. albogularis), C. cephus, C. ascanius, C. erythrotis, C. petaurista, C. mona, C. pogonias, C. wolfi, andC. aethiops, Miopithecus talapoin, Allenopithecus nigroviridis andErythrocebus patas, Lophocebus albigena, andCercocebus torquatus. Eleven loci (ten systems) were studied in red blood cell enzymes and the Gc, Gm, Km, and Bm systems in DBP and immunoglobulin serum proteins. Most of the loci were polymorphic. Similar and different polymorphisms occur in closely related species or subspecies, particularly inCercopithecus. Guenons have phenotypes clearly distinct from mangabeys.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Pharmaceutical research 6 (1989), S. 697-701 
    ISSN: 1573-904X
    Schlagwort(e): ultrasound ; phonophoresis ; temperature ; ibuprofen ; human skin ; in vitro percutaneous absorption
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The objective of this study was to develop an in vitro method to investigate the effect of ultrasound on the in vitro absorption of ibuprofen from a propylene glycol/water vehicle through human epidermis. A diffusion cell was modified so ultrasound could be applied to the vehicle and skin. Since ultrasound can increase the temperature underneath the area of application, control representing temperature effects ran concurrently to the ultrasound experiment. The results demonstrate that ultrasound can increase the penetration of ibuprofen through human skin. This increase in diffusion was greater than for controls where an equivalent increase in temperature was utilized. The results also indicate that evaporation of vehicle components may alter the skin/vehicle partition coefficient, decreasing the effects of ultrasound on the penetration of ibuprofen through the skin.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Evolutionary ecology 3 (1989), S. 343-359 
    ISSN: 1573-8477
    Schlagwort(e): Evolution ; exploitation ; fisheries ; Gadus morhua ; life history ; optimization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Age-specific exploitation of a natural population acts as a selective force on genetic variation in life history traits. Evolution arising from this selection may bring about evolutionary changes in the total yield which the population is able to sustain. An analysis of this process is given for a harvested population with densitydependent recruitment, in which selection of life history traits by cropping is independent of density and frequency. Evolution of the total yield depends on an interplay between the yield from an individual over the course of its life and recruitment; whether the total yield increases or decreases depends on the properties of particular populations. Evolution brought about by harvesting does not, in general, lead to the maximization of the total yield. Nonetheless, by appropriate choice of an age-specific harvest pattern, it is possible in principle to select the life history which gives the maximum total yield following evolution; this harvest pattern is called the ‘evolutionarily stable optimal harvesting strategy’ (ESOHS). Results of the analysis are illustrated with data on the Arcto-Norwegian cod.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 70
    ISSN: 1573-8248
    Schlagwort(e): Telenomus reynoldsi ; functional response ; Holling disc equation ; random parasite equation ; temperature ; Telenomus reynoldsi ; réponse fonctionnelle ; équation de Holling ; équation de la recherche au hasard de l'hôte ; température
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Beschreibung / Inhaltsverzeichnis: Résumé La réponse fonctionnelle deTelenomus reynoldsi Gordh et Coker à l'augmentation de la densité des œufs deGeocoris punctipes (Say) a été déterminée à 5 températures constantes en utilisant des boîtes de Pétri. Les courbes obtenues à toutes les températures étaient de Type II. Les durées du parasitisme (Th) et les taux de recherche de l'hôte (a) ont été estimés et comparés en utilisant l'équation «disc» de Holling. Le taux maximum du parasitisme (1/Th) s'est accru linéairement de 9 à 15 hôtes/jour avec l'accroissement de la température. La meilleure représentation de la relation entre le taux de recherche de l'hôte et la température a été obtenue par une équation quadratique. Le taux de recherche de l'hôte variait de 205 à 888 cm2/jour; il était maximum à 32° C. En utilisant l'équation du «random parasite» (parasite recherchant son hôte au hasard), l'analyse de la réponse fonctionnelle dans un terrain plus complexe contenant une plante artificielle, a conduit à des estimations plus précises du taux de recherche de l'hôte et du taux maximum du parasitisme, qui peuvent être utilisées pour décrire ces activités dans la nature. Le taux de la recherche de l'hôte était de 6680 cm2/jour, tandis que le taux maximum du parasitisme était de 13 hôtes/jour.
    Notizen: Abstract The functional response ofTelenomus reynoldsi Gordh & Coker was determined at 5 constant temperatures using a dish arena. Functional response curves at all temperatures were of Holling's Type II. Handling rate increased linearly with increasing temperature, whereas the relationship of search rate to temperature was best described by a quadratic model. Search rate was highest at 32°C. Using Rogers' random parasite equation, analysis of the functional response in a more complex arena containing an artificial plant provided estimates of search and handling rates that may be more appropriate in the field environment. Search rate was 6,680 cm2/day. Handling rate was 13 hosts/day.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    BioControl 34 (1989), S. 201-208 
    ISSN: 1573-8248
    Schlagwort(e): Notonecta ; embryos ; temperature ; Notonecta ; embryon ; température ; Notonecta ; embriones ; temperatura
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Beschreibung / Inhaltsverzeichnis: Résumé Les œufs deNotonecta unifasciata Guérin à différents stades de développment embryonnaire maintenus dans l'eau à des températures variables (2,2–25 °C) et durant de 4 à 12 semaines révèlent une viabilité maximale (〉80 %) à la température la plus forte. Cependant, la viabilité optimale sans développement se situait à 14.4 °C avec des embryons âgés de 8 jours (〉35 %). Un court stockage (4 semaines) à 14.4 °C augmente d'une façon significative la viabilité de l'œuf. La survie était faible (〈20 %) aux 2 températures les plus basses. Des œufs maintenus à 14.4 °C durant 12 semaines et supportant environ 50 % de mortalité peuvent être un procédé pratique de lutte biologique.
    Kurzfassung: Resúmen Huevecillos deNotonecta unifasciata mantenidos en varios estadios del desarrollo embrionarios y a varias temperaturas (2.2–25.6 °C) por 4–12 semanas, demostraron la mayor viabilidad (〉80 %) a la temperatura más alta. Sín embargo, la óptima viabilidad cuando no hubo desarrollo, se realizó en embriones de ocho días de edad, mantenidos a 14.4 °C. Almacenamiento de corto tiempo (cuatro semanas) a 14.4 °C se produjo un significante aumento de viabilidad. Superviviencia fué baja (〈20 %) a temperaturas menos de 8.3 °C. Se ofrece que huevecillos almacenados a 14.4 °C por 12 semanas, cuales se realizan un 50 % mortalidad, puede servir en la ejecución del control biológico.
    Notizen: Abstract Notonecta unifasciata Guerin eggs maintained at different stages of embryonic development in water at variable temperatures (2.2–25.6 °C) and for periods of 4–12 weeks revealed maximum viability (〉80 %) at the highest temperature. However, optimum nondevelopmental viability was at 14.4 °C with eight-day-old embryos (〉35 %). Short term (4 weeks) storage at 14.4 °C significantly increased egg viability. Survival was poor (〈20 %) at the 2 lowest temperatures. Eggs held at 14.4 °C for 12 weeks and sustainingca. 50 % mortality, may be a practical procedure for biological control.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 72
    ISSN: 1573-8248
    Schlagwort(e): Anagyrus pseudococci ; Leptomastix dactylopii ; Leptomastidea abnormis ; temperature ; adult longevity ; progeny production ; Anagyrus pseudococci ; Leptomastix dactylopii ; Leptomastidea abnormis ; température ; longévité des adultes ; descendance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Beschreibung / Inhaltsverzeichnis: Résumé La descendance augmente et la longévité de l'adulte décroît quand la température augmente entre 18°C et 30°C pour les 3 parasitoïdes de pseudococcines,Anagyrus pseudococci, (Girault),Leptomastix dactylopii Howard etLeptomastidea abnormis Girault. La distribution de Weibull donnait une bonne adaptation aux courbes de suvies pour les 3 parasitoïdes et la comparaison statistique à différentes températures des paramètresb etc de Weibull permettaient des changements dans l'échelle et la forme des courbes. En général les ♀♀ des 3 espèces vivaient plus longtemps que les ♂♂, excepté aux fortes températures. Les femelles deL. abnormis avaient leur descendance maximale à 24°C et la maintenaient à ce niveau jusqu'à 34°C. Elles vivaient plus longtemps que les 2 autres espèces de parasitoïdes à 30°C et manifestaient une courbe de survie de type I dans la gamme de températures examinées.A. pseudococci etL. dactylopii réclamaient tous deux de fortes températures (30°C) pour atteindre leur descendance maximale, mais vivaient moins longtemps à cette température. A 30°C les importante de la population qui mourrait dans les tous premiers jours.L. dactylopii vivait le plus longtemps à 26°C, les femelles manifestant une courbe de survie de type I à toutes les températures, tandis que les courbes de survie des mâles passaient du type I au type II à 30°C. Les implications de ces observations dans la dynamique des populations des différents parasitoïdes sont discutées brièvement.
    Notizen: Abstract Progeny production increased and adult longevity decreased with rising temperature within the range 18°C to 30°C for the 3 mealybug parasitoidsAnagyrus pseudococci (Girault),Leptomastix dactylopii Howard andLeptomastidea abnormis (Girault). The Weibull distribution gave a good fit to survival curves for the 3 parasitoids and statistical comparison of Weibullb andc parameters at different temperatures allowed changes in the scale and shape of the curves to be detected. In general, ♀♀ lived longer than ♂♂ for all 3 species, except at high temperature. FemaleL. abnormis attained their maximum progeny production at 24°C and maintained this level up to 34°C. They lived longer than the other 2 parasitoid species at 30°C and showed a type I survival curve throuhout the range of temperatures examined.A. pseudococci andL. dactylopii both required high temperatures (30°C) to attain their maximal progeny production, but werepseudococci tended towards type II, with a larger proportion of the population dying within the first few days.L. dactylopii lived longest at 26°C, with ♀♀ showing a type I survival curve at all temperatures and ♂ survival curves changing from type I to type II at 30°C. The implications of these findings for the population dynamics of the different parasitoids are briefly discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 48 (1988), S. 73-84 
    ISSN: 1570-7458
    Schlagwort(e): Liriomyza trifolii ; Agromyzidae ; Diptera ; temperature ; thresholds ; life history ; feeding ; intrinsic rate of increase ; tomato ; host-plant suitability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé La vitesse de développement, la mortalité, l'alimentation, la fécondité et la longévité de L. trifolii (Burgess) élevés sur plants de tomates du cultivar ‘Moneydor’ ont été examinées au laboratoire sous 3 températures constantes (15°C, 20°C et 25°C) et une thermopériode (16/22°C, moyenne 19,5°C). Les taux de développement et les seuils de chaque stade ont été déterminés à partir des droites de régressions. Aucune corrélation n'a été mise en évidence entre ces variables biologiques et la taille des pupes. De plus, certaines données sur la biologie de L. trifolii sont fournies et discutées. Le taux intrinsèque d'accroissement, rm a varié de-0,0023 oeuf viable/femelle/jour à 15°C à 0,1254 oeuf viable/femelle/jour à 25°C et la reproduction nette de 1 oeuf femelle viable/femelle à 15°C à 26 oeufs femelles viables/femelle à 25°C. La durée d'une génération a varié de 48 jours à 15°C à 24 j à 25°C. 90% de la ponte a eu lieu dans les 115 premiers degrés jours de la vie imaginale à 20 et 25°C. La fécondité et la longévité étaient fortement liées au nombre de piqûres nutritionnelles. Ces résultats montrent que la tomate est un hôte convenable permettant aux populations de L. trifolii de se développer lorsque la température est supérieure à 16°C.
    Notizen: Abstract The effects of three constant (15°C, 20°C and 25°C) and one alternating (16–22°C, mean 19.5°C) temperatures on development, mortality, feeding, fecundity and longevity of Liriomyza trifolii (Burgess) on tomato plants cv. ‘Moneydor’ were examined in the laboratory. Development rates and thresholds for each instar were estimated by means of linear regression. No correlation was found between life history variables and pupal length. Further, data on the biology of L. trifolii are given and discussed. The intrinsic rate of increase, rm, varied from-0.0023 viable female eggs/⧫/day at 15°C to 0.1254 eggs/⧫/day at 25°C and net reproduction from one viable female egg/⧫ at 15°C to 26 eggs/⧫ at 20°C. Generation time varied from 48 days at 15°C to 24 days at 25°C. Ninety % oviposition occurred within the first 115 degree-days of adult life at both 20°C and 25°C. Fecundity and longevity were highly correlated with the number of feeding punctures. The data indicate that tomato is a suitable host plant allowing populations of L. trifolii to increase if temperatures are above 16°C.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 46 (1988), S. 19-28 
    ISSN: 1570-7458
    Schlagwort(e): Hymenoptera ; Encyrtidae ; parasitoids ; Pseudococcidae ; mealybugs ; Anagyrus pseudococci ; Leptomastix dactylopii ; Leptomastidea abnormis ; temperature ; predicting development ; thresholds ; temperate glasshouses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Les vitesses de développement de 3 parasitoïdes de cochenilles ont été étudiées dans les conditions de température de serre, avec thermopériode ou en température constante. En conditions constantes, la vitesse augmente jusqu'à 35°C, mais est létale à 40°C. Avec thermopériode, une thermophase de 40°C peut être tolérée pendant 12 heures. Les vitesses de développement sous thermopériodes pourraient être calculées à partir des données obtenues en conditions constantes, modifiées en fonction des durées respectives des cryophases et thermophases. Une méthode originale est présentée pour obtenir les seuils inférieurs de développement, en utilisant des thermopériodes, et pour calculer les vitesses de développement à températures élevées. Une méthode de régression polynomiale, non vérifiée préalablement, a été utilisée pour prévoir les durées moyennes des développements sous serre. Ces estimations sont beaucoup plus sûres que les prédictions basées sur le concept de degré-jour (Do), lorsque les températures extrêmes durent longtemps, mais en serre chaude elles ne présentent aucune différence significative. De plus, une méthode d'évaluation des 95% d'émergences, a donné de bonnes estimations des premières et dermières émergences en conditions périodiques.
    Notizen: Abstract Developmental rates of three encyrtid mealybug parasitoids were examined under constant, cycling and glasshouse temperatures. Under constant conditions the rate of development increased with rising temperature up to 35°C, but a constant 40°C was lethal. Under cycling conditions, 12 h periods at 40°C could be tolerated. Developmental rates under cycling conditions could be calculated from constant temperature data, by incrementing development on an h/h basis. A new technique was developed to determine the lower thresholds for development, using cycling regimes and to calculate the rates of development over short periods at high temperature. A previously untested polynomial regression technique was used to predict mean developmental periods under glasshouse conditions. These predictions were considerably more accurate than day-degree (Do) predictions when substantial periods at extreme temperatures were involved, but not significantly different from day-degree predictions under ‘hot-house’ conditions. In addition a method was developed to calculate a 95% range for emergence, which gave consistently good estimates of first and last eclosion observed under fluctuating conditions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 47 (1988), S. 173-182 
    ISSN: 1570-7458
    Schlagwort(e): Bembidion lampros ; Pterostichus cupreus ; Carabidae ; Coleoptera ; behaviour ; temperature ; searching ; consumption ; cereal aphid ; Rhopalosiphum padi ; prey ; density ; barley
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Les taux maximum de consommation de R. padi L. à différentes températures ont été déterminés au laboratoire chez deux carabes, B. lampros Herbstet P. cupreus L. La consommation moyenne a augmenté avec la température chez les deux espèces, B. lampros consommant un maximum de 15,9 larves des stades 1 à 3 et 9,1 pucerons adultes aptères, à 25°C. P. cupreus a été particulièrement vorace et a consommé 125,3 adultes aptères par jour à 20°C. Le comportement des deux espèces a été observé en filmant en vidéo des carabes à jeun, maintenus à différentes températures constantes, dans des enceintes semées en orge de printemps. Des éléments du comportement, communs aux deux espèces, ont été définis: 1) immabilité, 2) marche et course, 3) recherche, 4) affrontement. P. cupreus a été plus actif à toutes les températures, B. lamprosa été inactif au-dessous de 10°C. La part de temps consacrée à la recherche, le nombre de plantes prospectées, et la vitesse ont augmenté avec la température chez les deux espèces. Dans des enceintes similaires colonisées par R. padi, P. cupreus a significativement augmenté le temps consacré à la recherche dans les enceintes, parallèlement à l'augmentation de la densité des pucerons. Après la découverte d'une colonie de pucerons, P. cupreus escalade et prospecte la plante et ses voisines immédiates; tandis que les plantes des enceintes sans pucerons sont rarement escaladées. B. lampros n'a pas été observé escaladant des plantes d'enceintes avec ou sans pucerons, et il n'a pas accru son temps de prospection en fonction de la densité de pucerons. Les quelques B. lampros qui ont capturé des pucerons l'ont fait lorsque ceux-ci marchaient sur la surface du sol. La discussion a porté sur l'efficacité relative des deux carabes comme prédateurs de R. padi, et les résultats ont été comparés à ceux d'études du même type, menées ailleurs, avec des prédateurs de Sitobion avenae sur blé d'hiver.
    Notizen: Abstract Maximum consumption rates were determined for two carabids, Bembidion lampros Herbst. and Pterostichus cupreus L., feeding on the cereal aphid Rhopalosiphum padi L. at different temperatures in the laboratory. Mean daily consumption increased with increasing temperature for both species, B. lampros consuming a maximum of 16 1–3 instar nymphs and 9 apterous adult aphids at 25°C. P. cupreus was particularly voracious and consumed 125 apterous adult R. padi per day at 20°C. The behaviour of both species was analysed by video filming starved beetles, maintained at different constant temperatures, in arenas sown with spring barley. The behavioural components (1) still; (2) run/walk; (3) search and (4) confrontation were identified and were common to both species. P. cupreus was more active over the temperature range tested; B. lampros was inactive under 10°C. The proportion of time spent searching, number of plants searched, and velocity increased with increasing temperature for both species. When observed in similar arenas seeded with R. padi colonies, individuals of P. cupreus significantly increased their time spent searching in arenas with increasing aphid density. Following discovery of an aphid colony, individuals climbed and searched the host plant and its nearest neighbours. Plants in aphid free arenas were rarely climbed. B. lampros was not observed climbing in either aphid free arenas or in arenas with increasing aphid densities, and did not significantly increase its time spent searching in response to increased prey density. The few B. lampros that found aphids caught them walking on the soil surface. The relative efficiences of these two carabids as predators of R. padi are discussed, and the results are compared with similar studies elsewhere with predators of Sitobion avenae on winter wheat.
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  • 76
    ISSN: 1432-0983
    Schlagwort(e): Wheat chloroplast DNA ; Repeated sequences ; Ribosomal protein genes ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Some dispersed repeated sequences and their flanking regions from wheat and maize ctDNAs have been characterized. Two sets of wheat ctDNA repeats were found to be the chloroplast ribosomal protein genesrpl2 andrpl23, plus nonfunctional segments of them, designatedrpl2′ andrpl23′. Pairwise comparisons were made between the wheatrp123 andrpl23′, and the maizerp123′ sequences. The precise patterns of homology suggest that the divergence of the wheat and maize nonfunctional (rpl23′) sequences is being retarded by nonreciprocal recombination, biased by selection for individuals with functional (rpl23) sequences. The implied involvement of these sequences in mechanisms of homologous recombination, and therefore in the creation and spread of new ctDNA variants, is discussed.
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  • 77
    ISSN: 1432-0983
    Schlagwort(e): Physarum polycephalum ; rRNA ; Sequence ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The nucleotide sequence of the Physarum polycephalum small subunit ribosomal RNA (SSU rRNA) gene has been determined. Sequence data indicate that the mature 19S SSU rRNA is 1,964 nucleotides long. A complete secondary structure model for P. polycephalum SSU rRNA has been constructed on the basis of the Escherichia coli 16S rRNA model and data from comparative analyses of 28 different eukaryotic sequences. A “four-helix” model is presented for the central domain variable region. This model can be applied both to vertebrate and most lower eukaryotic SSU rRNAs. The increased size of P. polycephalum SSU rRNA relative to the smaller SSU rRNAs from such other lower eukaryotes, as Dictyostelium, Tetrahymena or Saccharomyces is due mainly to three G+C-rich insertions found in two regions known to be of variable length in eukaryotes. In a phylogenetic tree constructed from pairwise comparisons of eukaryotic SSU rRNA sequences, the acellular myxomycete P. polycephalum is seen to diverge before the appearance of the cellular mycomycete Dictyostelium discoideum.
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  • 78
    ISSN: 1432-0983
    Schlagwort(e): Evolution ; Sequence comparison ; RUBISCO ; Transit peptide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have isolated and characterized a full-length cDNA clone encoding the precursor of the small subunit (pSU) of ribulose-1,5-bisphosphate carboxylase/oxygenase (RUBISCO) from the green alga, Chlamydomonas moewusii. Comparison with the C. reinhardtii rbcS1 gene sequence reveals that both small subunit (SS) coding regions are 75% homologous and that their predicted mature polypeptide chains are each composed of 140 amino acids. In contrast, their transit peptides appear to be divergent. We also show that transcription of the C. moewusii rbcS gene(s) which generates a 1,230 and a 930 base mRNA species are light-stimulated/or accumulated during the light period of the cell cycle. Finally, the SS polypeptide sequences of fifteen different photosynthetic organisms are compared; this analysis reveals at least five well-conserved polypeptide domains.
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 28 (1988), S. 98-112 
    ISSN: 1432-1432
    Schlagwort(e): rRNA ; Evolution ; Sequence comparison ; Parsimony ; Bootstrap
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Sequences of small subunit (SSU) and large subunit (LSU) ribosomal RNA genes from archaebacteria, eubacteria, and the nucleus, chloroplasts, and mitochondria of eukaryotes have been compared in order to identify the most conservative positions. Aligned sets of these positions for both SSU and LSU rRNA have been used to generate tree diagrams relating the source organisms/organelles. Branching patterns were evaluated using the statistical bootstrapping technique. The resulting SSU and LSU trees are remarkably congruent and show a high degree of similarity with those based on alternative data sets and/or generated by different techniques. In addition to providing insights into the evolution of prokaryotic and eukaryotic (nuclear) lineages, the analysis reported here provides, for the first time, an extensive phylogeny of the mitochondrial lineage.
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  • 80
    ISSN: 1432-1432
    Schlagwort(e): Aspergillus nidulans ; 5S rRNA ; Pseudogenes ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary AllAspergillus nidulans 5S rRNA pseudogenes known so far are the result of integration of an approx. 0.2-kbp-long DNA sequence into the 5S rRNA genes. This sequence, called block C, is present in at least five copies in theA. nidulans genome and seems to be associated either with 5S rRNA genes or pseudogenes. In contrast to the 78% sequence conservation of the C-block in pseudogenes, the truncated 5′ halves of the pseudogenes are very highly conserved (96.9–100%). We postulate that the 5S rRNA pseudogenes are still a subject of concerted evolution. The C-block sequence shows similarity to the switch region of the mouse heavy chain immunoglobulin gene. A characteristic motif GGGTGAG is repeated several times in both sequences; the sequence conservation is 63%.
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  • 81
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 27 (1988), S. 228-235 
    ISSN: 1432-1432
    Schlagwort(e): Tropomyosin ; Differential splicing ; Evolution ; Isochore ; Codon usage ; Sequence convergence ; Functional constraints
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have cloned and determined the nucleotide sequence of a complementary DNA (cDNA) encoded by a newly isolated human tropomyosin gene and expressed in liver. Using the leastsquare method of Fitch and Margoliash, we investigated the nucleotide divergences of this sequence and those published in the literature, which allowed us to clarify the classification and evolution of the tropomyosin genes expressed in vertebrates. Tropomyosin undergoes alternative splicing on three of its nine exons. Analysis of the exons not involved in differential splicing showed that the four human tropomyosin genes resulted from a duplication that probably occurred early, at the time of the amphibian radiation. The study of the sequences obtained from rat and chicken allowed a classification of these genes as one of the types identified for humans. The divergence of exons 6 and 9 indicates that functional pressure was exerted on these sequences, probably by an interaction with proteins in skeletal muscle and perhaps also in smooth muscle; such a constraint was not detected in the sequences obtained from nonmuscle cells. These results have led us to postulate the existence of a protein in smooth muscle that may be the counterpart of skeletal muscle troponin. We show that different kinds of functional pressure were exerted on a single gene, resulting in different evolutionary rates and different convergences in some regions of the same molecule. Codon usage analysis indicates that there is no strict relationship between tissue types (and hence the tRNA precursor pool) and codon usage. G+C content is characteristic of a gene and does not change significantly during evolution. These results are in good agreement with an isochore composition of the genome, and thus suggest a similar chromosomal environment in chicken, rat, and human.
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 27 (1988), S. 291-297 
    ISSN: 1432-1432
    Schlagwort(e): P1 P2 protamines ; Evolution ; Regulatory sequence ; Primordial sequence ; Similarity ; Alignment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary With the recent availability of the primary structural data for the trout, bovine, and mouse protamine genes, a detailed comparison of their structures has been made. This has revealed extensive conservation of potentially biologically significant regions. An inverse correlation is apparent between gene copy number and the number of sequence-distinct protamines synthesized with the number of CP-box-like (CCYPCCC) putative transcription modulating sequences situated 5′ to these genes. A common nucleotide sequence 5′ to the CP-box-like putative transcription modulating sequence(s) at the end of a common region has been identified. It is postulated that this is the testis-specific protamine P1 transcription regulator sequence. Evidence based on sequence similarity is also provided for the existence of a primordial protamine gene and a scheme for the evolution of vertebrate protamine genes is proposed.
    Materialart: Digitale Medien
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  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 27 (1988), S. 17-28 
    ISSN: 1432-1432
    Schlagwort(e): Actin genes ; Evolution ; 5′ and 3′ untranslated regions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have sequenced the coding and leader regions, as well as part of the 3′ untranslated region, of aXenopus borealis type 1 cytoskeletal actin gene [defined according to the arrangement of acidic residues at the N-terminus; Vandekerckhove et al. (1981) J Mol Biol 152:413–426]. The encoded amino acid sequence is the same as the avian and mammalian β (type 1) cytoskeletal actins, except for an isoleucine at position 10 (as found in the mammalian γ cytoskeletal actins), and an extra amino acid, alanine, after the N-terminal methionine. Five introns were found, in the same positions as those of the rat and chicken β-actin genes. The 5′ and 3′ untranslated regions resemble those of the human γ (type 8) cytoskeletal actin gene more closely than the mammalian β genes. Primer extension showed that this type 1 gene is transcribed in ovary and tadpole. Sequencing of primer extension products demonstrated two additional mRNA species inX. borealis, encoding type 7 and 8 isoforms. This contrasts with the closely related speciesXenopus laevis, where type 4, 5, and 8 isoforms have been found. The type 7 isoform has not previously been found in any other species. The mRNAs of theX. borealis type 1 and 8 andX. laevis type 5 and 8 isoforms contain highly homologous leaders. TheX. borealis type 7 mRNA has no leader homology with the other mRNA species and, unlike them, has no extra N-terminal alanine codon. The evolutionary implications of these data are discussed.
    Materialart: Digitale Medien
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  • 84
    ISSN: 1432-1432
    Schlagwort(e): Histone genes ; Sea stars ; Echinoderms ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The arrangement of core histone genes and their transcriptional polarity has been determined for three species of sea stars (Pisaster ochraceus, P. brevispinus, andDermasterias imbricata) representing two orders which diverged over 500 million years ago. Each species has approximately 500 core histone cluster repeats per haploid genome. The close phylogenetic relationship between thePisaster species is evident from the correspondence of restriction sites in the repeat element, identical arrangement of core histones, and high degree of sequence homology in both the coding and spacer regions of the H3 gene. TheDermasterias repeat has the same gene order and transcriptional polarity of core histones, but its restriction map is significantly different. Moreover, theDermasterias H3 gene has the same amino acid sequence, but in comparison toPisaster nucleotide sequences, shows a high level of silent substitutions. Analyses of the nucleotide sequence of the 5′ and 3′ regions surrounding the H3 gene from each species demonstrate the presence of appropriately spaced consensus and processing signal segments. The 3′ spacer segment of theDermasterias H4 gene contains an unusual, threefold tandemly repeated, 21-nucleotide, AT-rich sequence. No similar sequence is seen in theP. brevispinus H4 3′ region, but these two species show a striking regularity of distribution of five different homologous oligomers in the 3′ spacer.
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 27 (1988), S. 102-108 
    ISSN: 1432-1432
    Schlagwort(e): Hemopexin ; Evolution ; Gene structure ; Recombination ; Sequence homology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The human hemopexin gene was isolated and its structure determined. The gene spans approximately 12 kb and is interrupted by nine introns. When the intron/exon pattern was examined with respect to the polypeptide segments they encode, a direct correspondence between exons and the 10 repeating units in the protein was observed. The introns are not randomly placed; they fall in the middle of the region of amino acid sequence homology in strikingly similar locations in 6 of the 10 units and in a symmetrical position in the two halves of the coding sequence. These features strongly support the hypothesis that the gene evolved through intron-mediated duplications of a primordial sequence to a five-exon cluster. A more recent gene duplication led to the present-day gene organization.
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  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 17 (1988), S. 251-266 
    ISSN: 1573-0867
    Schlagwort(e): Zinc ; controlled-release ; diffusion ; pH ; temperature ; phosphate ; clay ; sand ; moisture content
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The emission and movement of zinc from planar arrangements of controlled-release (C.R.) thermoplastic matrix zinc fertilizer formulations was studied in cylindrical diffusion cells packed with a clay or a sand. The influences of a number of soil characteristics known to affect zinc diffusion were also investigated. Zinc emission was initially (over 2 days) very rapid. The rate declined markedly thereafter. Morphologically distinct C.R. zinc formulations released zinc at different rates. Zinc moved appreciably and consistently further in the sand than in the clay. Of the soil characteristics studied, increasing phosphate levels had no effect upon zinc emission or mobility in either soil. Increasing pH in the sand did not affect zinc emission, but decreased zinc mobility. Conversely, in the two soils, increasing temperature stimulated zinc emission, but had little influence on zinc mobility. At higher water contents, zinc release was increased in both soils. However, zinc movement was only increased in the sand.
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  • 87
    ISSN: 1420-9136
    Schlagwort(e): Middle atmosphere ; temperature ; neutral and ion composition ; turbulent transfer ; model
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Using a numerical model for temperature and neutral and ion composition behaviour at middle atmospheric heights, an analysis has been made of the dependence of atmospheric structural parameters on temperature, solar activity, and on turbulent transfer intensity. For mesospheric heights, an inverse dependence of the nitric oxide density on the temperature has been found. It is thus possible to explain experimentally obtained temperature variations over a cyclc of solar activity at mesospheric and lower thermospheric heights. Numerical simulation results indicate that the temperature in the height range ∼75–120 km depends considerably on both the absolute values of turbulent transfer coefficients and their vertical gradients.
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 150 (1988), S. 56-60 
    ISSN: 1432-072X
    Schlagwort(e): Fumarate reduction ; Quinones ; Rhodospirillaceae ; Phototrophic bacteria ; Evolution ; Taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Nineteen established and one undesignated species of the Rhodospirillaceae were examined for fumarate reduction in connection with their quinone systems. The fumarate reductase activity with reduced methyl viologen (MVH) or FMNH2 as electron donor was found in membrane (chromatophore) preparations from phototrophically grown cells of all species containing menaquinone (MK) and/or rhodoquinone. The species having ubiquinone as the sole quinone contained no fumarate reductase activity, except some Rhodobacter species showing the FMNH2-dependent activity. The MVH-fumarate reductase activity of the MK-type species was not inhibited by Triton X-100 or acetone treatment, suggesting the presence of a fumarate reductase reacting directly with MVH, while such an enzyme was absent in the MK-lacking strains, with few exceptions. The FMNH2-fumarate reduction system was abolished by a detergent or acetone extraction in all bacteria but differed much among species with different quinone types as to the response to respiratory inhibitors. These differences in fumarate-reducing properties and quinone systems among the phototrophic bacteria are discussed from evolutionary and taxonomic viewpoints.
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 150 (1988), S. 103-104 
    ISSN: 1432-072X
    Schlagwort(e): Eubacteria ; Evolution ; Extreme thermophile ; Thermotoga
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A second species of the extremely thermophilic, eubacterial genus Thermotoga is described as clearly distinguished from the type species Thermotoga maritima by physiological and phylogenetic criteria. It is named Thermotoga neapolitana.
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Journal of mathematical biology 26 (1988), S. 347-357 
    ISSN: 1432-1416
    Schlagwort(e): Transposable elements ; Evolution ; Branching processes ; Population genetics ; Mobile genetic elements
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Mathematik
    Notizen: Abstract A discrete-time multitype branching process model is presented for the evolution of transposable elements in haploid populations. An individual is classified as type i if it possesses i copies of the TE, i⩾0. The general model incorporates copy-dependent selection and transposition, and recursion relations are derived for the distribution of the number of individuals of the various types. The asymptotic relative proportions of individuals of the different types is studied in the neutral case. The behavior of this equilibrium distribution is examined for various patterns of regulated transposition and deletion.
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    The journal of membrane biology 103 (1988), S. 149-158 
    ISSN: 1432-1424
    Schlagwort(e): H+ pump ; K+ channel ; light ; Nitella ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary At membrane potentials different fromE K, the temperature effect on membrane potential ofNitella consists of two components. One of them changes its sign atE K, the other one does not. This leads to the assignment of these components to changes in the K+ channel and in the H+ pump, respectively. It is shown that the fast time constant (3 to 30 sec) of the temperature effect on the H+ pump measured as a change in membrane potential and that of the temperature effect on the K+ channel measured as a change in resistance (having about twice the value of that of the pump) are sensitive to light intensity. Both time constants measured inNitella become smaller if light intensity increases from 0 to 15 Wm−2. This supports the suggestion of Fisahn and Hansen (J. Exp. Bot. 37:440–460, 1986) that temperature acts on plasmalemma transport via photosynthesis via the same mechanism as light does.
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    The journal of membrane biology 101 (1988), S. 67-72 
    ISSN: 1432-1424
    Schlagwort(e): hemolysis ; membrane ; erythrocyte ; pyrexia ; phospholipid ; phase transition ; unilamellar ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary Rates of human red blood cell hemolysis were measured as a function of temperature. Three distinct temperature intervals for hemolysis were noted: a) At temperatures equal to or less than 37°C no hemolysis was observed for the duration of the incubation (30 hr). b) For temperatures exceeding 45°C hemolysis rates are rapid and are accompanied by gross changes in cellular morphology. The activation energy for hemolysis is 80 kcal/mole; this value is characteristic of protein denaturation and enzyme inactivation suggesting that these processes contribute to hemolysis at these high temperatures. c) Between 38 and 45°C the energy of activation is 29 kcal/mole, indicating that a fundamentally different process than protein inactivation is responsible for hemolysis at these relatively low temperatures. A mechanism based on the concept of the critical bilayer assembly temperature of cell membranes (N.L. Gershfeld,Biophys. J. 50:457–461, 1986) accounts for hemolysis at these relatively mild temperatures: The unilamellar state of the membrane is stable at 37°C, but is transformed to a multibilayer when the temperature is raised; hemolysis results because formation of the multibilayer requires exposing lipid-free areas of the erythrocyte surface. An analysis of the activation energy for hemolysis is presented that is consistent with the proposed unilamellar-multibilayer transformation.
    Materialart: Digitale Medien
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  • 93
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 252 (1988), S. 349-358 
    ISSN: 1432-0878
    Schlagwort(e): Thyroglobulin ; Sulfation ; Thyroid gland ; Vertebrates ; Evolution ; Trout (Salmo gairdnerii) ; Clawed toad (Xenopus laevis) ; Chicken
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Mammalian thyroglobulin is released by thyroid follicle cells as a sulfated glycoprotein; the sulfate residues are mostly linked to tyrosine, but they are also attached to the high-mannose carbohydrate side-chains. To decide whether sulfation of thyroglobulin is confined to mammals, representatives of other vertebrate classes were analyzed for the presence of sulfated thyroglobulin: fish (trout), amphibians (clawed toad) and birds (chicken). Mini-organs were prepared from thyroid tissue and suspended in a 35SO 4 -- -containing culture medium. Light- and electron-microscope autoradiographs prepared from the mini-organs showed that thyroid follicle cells from all species examined incorporate 35SO 4 -- and synthesize a sulfated secretory product which accumulates in the follicle lumen. The Golgi complex was detected as the primary intracellular site of sulfate organification. The 35SO 4 -- -radiolabeled secretory product of all species was shown by polyacrylamide-gel-electrophoretic analyses to consist of thyroglobulin, identified by comparison with biosynthetically 125I-labeled thyroglobulin. The results indicate that the sulfation of thyroglobulin is a ubiquitous post-translational modification observed already in the thyroglobulin of lower vertebrates. Our observations suggest that sulfation of thyroglobulin was acquired in the early stages of thyroid evolution.
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 31 (1988), S. 379-383 
    ISSN: 1871-4528
    Schlagwort(e): rooting ; temperature ; daylength ; transplanting ; yield
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A series of experiments were conducted in Vietnam to develop a system whereby detached sprouts from physiologically old green sprouted seed tubers could be used to grow potatoes. Three node segments from the mid or basal portion of the detached sprout produced the greatest percentage of shoots and roots. Growth was best in a medium of equal parts of sub-soil, pig manure and brick kiln ash. Sprout cuttings produced plantlets ready for transplanting in 14–20 days with mean daily temperatures of 22 to 24°C. When transplanted in mid-November, yields from sprout cuttings in field experiments were 10 to 18 t/ha which were 33% lower than from healthy seed tubers but more than the national average yield using degenerated seed tubers. Tubers produced by plants grown from sprout stored well and gave good yields when replanted the following year.
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 214 (1988), S. 439-450 
    ISSN: 1617-4623
    Schlagwort(e): trpA ; trpB ; Methanococcus voltae ; Archaebacteria ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A cosmid bank of Methanococcus voltae DNA was obtained in Escherichia coli after ligation of partially HindIII-digested M. voltae DNA in the HindIII site of the transferable cosmid pVK100. The bank was used to perform complementation experiments with E. coli auxotrophic mutants. Five cosmids complementing trpA shared three adjacent HindIII fragments of 2.1, 2.3 and 14 kb. Two of these cosmids also complemented trpD and carried an additional 4.2 kb HindIII fragment. The trpA- and trpD-complementing regions were more precisely localized using Tn5 mutagenesis. A 1.7 kb PstI fragment, cloned into pUC9 in both orientations, was responsible for the trpA complementation. This fragment was sequenced and an open reading frame (ORF) of 852 nucleotides (ORFtrpA) encoding a 284 amino acid polypeptide of mol. wt. 31938 was found. The amino acid sequence was compared with that of the α subunit of tryptophan synthase (trpA gene product) from nine eubacterial species and to the N-terminal part of the tryptophan synthase of Saccharomyces cerevisiae (TRP5 gene product). Similarity varied from 24% (Brevibacterium lactofermentum) to 35% (S. cerevisiae). The nucleotide sequence of the region upstream from M. voltae ORFtrpA was determined and revealed the presence of an ORF of 1227 nucleotides (ORFtrpB) encoding a 409 amino acid polypeptide of mol. wt. 44634. The polypeptide sequence was similar to the β subunit of tryptophan synthase (trpB gene product) from six eubacterial species and to the C-terminal part of the tryptophan synthase of S. cerevisiae. Similarity varied from 49% (S. cerevisiae, B. lactofermentum) to 58% (Pseudomonas aeruginosa). This high conservation supports the hypothesis of a common ancestor for the trpA and trpB genes of archaebacteria, eubacteria and eucaryotes. M. voltae ORFtrpA and ORFtrpB, which are transcribed in the same direction, are separated by a 37 bp AT-rich region. Immediately upstream from ORFtrpB, the 3′ end of an ORF homologous to E. coli and Bacillus subtilis trpF was found. As the trpD-complementing region was located upstream from the trpFBA sequenced region, the organization of trp genes in the archaebacterium might thus be trpDFBA. Such an organization resembles that of enteric eubacteria, in which the trpEDCFBA genes are grouped in a single operon. However, M. voltae ORFtrpA and ORFtrpB do not overlap, in contrast with what is found in most eubacteria.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 159 (1988), S. 229-235 
    ISSN: 1615-6110
    Schlagwort(e): AngiospermsPoaceae ; Triticum ; Evolution ; in situ hybridization ; biotin labelling ; G genome chromosomes ; repeated DNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The somatic chromosomes ofTriticum turgicum var.durum cv. Langdon andT. dicoccoides (AABB tetraploids),T. timopheevii, andT. araraticum (AAGG tetraploids) were assayed for distribution patterns of a highly repeated 120bp DNA sequence by in situ hybridization. The repeated sequence appears to be an ancient sequence shared withSecale andAegilops. The distribution patterns of the chromosomes were compared to the patterns of the A and B genome chromosomes ofT. aestivum cv. Chinese Spring (AABBDD hexaploid).T. turgidum andT. dicoccoides were observed to have identical in situ hybridization patterns. In both species, nine chromosomes with a total of 21 sites of hybridization were observed. The pattern, with few exceptions, was identical to that of Chinese Spring.T. araraticum andT. timopheevii were observed to have different patterns. InT. araraticum, six chromosomes with 21 total hybridization sites are present while inT. timopheevii nine chromosomes with 19 total sites exist. Major differences in hybridization patterns were observed between the B and G genomes. The divergence of the tetraploid wheats in this study appears to have resulted in changes in location, not in amount, of the ancient repeated sequence.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Biology and philosophy 3 (1988), S. 29-47 
    ISSN: 1572-8404
    Schlagwort(e): Louis Agassiz ; Empiricism ; Cladism ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Abstract The philosophy of “pattern cladism” has been variously explained by reference to the work of Louis Agassiz. The present study analyzes Agassiz's attempt to combine an empirical approach to the study of nature with an idealistic philosophy. From this emerges the problem of empiricism and of the isomorphy between the order of nature and human thinking. The analysis of the writings of Louis Agassiz serves as the basis for discussion of the “reality” of natural groups as postulated by pattern cladists.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Plant ecology 74 (1988), S. 107-112 
    ISSN: 1573-5052
    Schlagwort(e): Biogeography ; Desert ; Evolution ; Gradient ; Larrea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In this paper the hypothesis is tested that the local distributions of perennial plants on a desert bajada are related to those at the regional/geographical level. Plant species reaching their highest density in the lower, mid-, or upper plant association on the bajada showed no difference in their latitudinal centers of distribution, or the latitudinal variation over the region. However, plants in the three associations did differ significally in the standardized distance of their regional distribution from the target bajada: i.e., plant species characteristic of the mid-bajada were significantly closer to their regional distribution centers than were plants in the lower or upper association. These results suggest that the local distribution of plants on desert bajadas are related to those at the regional level. Consideration of historical source-pools may provide a key to understanding both the ecological and biogeographic components of plant associations in North American desert regions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    Springer
    Pharmacy world & science 10 (1988), S. 93-95 
    ISSN: 1573-739X
    Schlagwort(e): Anthracyclines ; Chemistry ; Drug stability ; Mitomycins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Pharmacy world & science 10 (1988), S. 101-116 
    ISSN: 1573-739X
    Schlagwort(e): Chemistry ; Chromatography ; Etoposide ; Immunoassay ; Metabolism ; Podophyllotoxin ; Pharmacokinetics ; Teniposide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Etoposide (VP 16-213) and teniposide (VM 26) are semisynthetic epipodophyllotoxin derivatives active against a variety of tumours. The clinical efficacy has led to an increasing interest in these compounds. This review presents information on the mechanism of action, biochemical pharmacology, bioanalysis, metabolism and pharmacokinetics of etoposide and teniposide.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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