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  • 1
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    Springer Nature | Springer
    Publication Date: 2024-04-05
    Description: This open access book offers the first comprehensive account of the pan-genome concept and its manifold implications. The realization that the genetic repertoire of a biological species always encompasses more than the genome of each individual is one of the earliest examples of big data in biology that opened biology to the unbounded. The study of genetic variation observed within a species challenges existing views and has profound consequences for our understanding of the fundamental mechanisms underpinning bacterial biology and evolution. The underlying rationale extends well beyond the initial prokaryotic focus to all kingdoms of life and evolves into similar concepts for metagenomes, phenomes and epigenomes. The book’s respective chapters address a range of topics, from the serendipitous emergence of the pan-genome concept and its impacts on the fields of microbiology, vaccinology and antimicrobial resistance, to the study of microbial communities, bioinformatic applications and mathematical models that tie in with complex systems and economic theory. Given its scope, the book will appeal to a broad readership interested in population dynamics, evolutionary biology and genomics.
    Keywords: Microbial Genetics and Genomics ; Evolutionary Biology ; Genetics and Population Dynamics ; Microbial Ecology ; Human Genetics ; Genetics and Genomics ; Comparative genomics ; Metagenomics ; Microbial Population Analysis ; Pangenome Profile ; Supra-Genome Analysis ; Adaptive Evolution ; Computational Tools ; Bioinformatic Genomics ; Core Dispensable Genome ; Selection, Recombination, Composition ; Acquired Resistance ; Bacterial Species Concept ; Genomic Diversity ; Bacterial Ecology, Microevolution ; Open Access ; Pan-metagenomics ; Pan-microbiomics ; Pan-epigenome ; Gene Transfer ; Pan-phenomes ; Microbiology (non-medical) ; Genetics (non-medical) ; Evolution ; Applied mathematics ; Ecological science, the Biosphere ; Medical genetics ; thema EDItEUR::P Mathematics and Science::PS Biology, life sciences::PSG Microbiology (non-medical) ; thema EDItEUR::P Mathematics and Science::PS Biology, life sciences::PSA Life sciences: general issues::PSAJ Evolution ; thema EDItEUR::P Mathematics and Science::PB Mathematics::PBW Applied mathematics ; thema EDItEUR::P Mathematics and Science::PS Biology, life sciences::PSA Life sciences: general issues::PSAF Ecological science, the Biosphere ; thema EDItEUR::M Medicine and Nursing::MF Pre-clinical medicine: basic sciences::MFN Medical genetics ; thema EDItEUR::P Mathematics and Science::PS Biology, life sciences::PSA Life sciences: general issues::PSAK Genetics (non-medical)
    Language: English
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  • 2
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    Springer
    In:  Heidelberg, Springer, vol. 113, no. XVI:, pp. 1-14, (ISBN 1-56670-263-3)
    Publication Date: 1999
    Keywords: Handbook of geophysics ; Seismology ; Seismics (controlled source seismology) ; Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Earthquake hazard ; KTB ; ICDP ; IOcean Drilling Program ; climate ; Antarctica ; Nuclear explosion ; Volcanology ; GeodesyY ; satellites ; remote ; sensing ; gas ; hydrates ; Geothermics ; Energy (of earthquakes) ; potable ; water ; waste ; soils ; evolution ; Geol. aspects ; geotechnics ; Engineering geophys. ; ores
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 36 (1997), S. 299-302 
    ISSN: 1436-6215
    Keywords: Energy retention ; protein retention ; fat retention ; growth ; body composition ; broilers ; Energieansatz ; Proteinansatz ; Fettansatz ; Wachstum ; Körperzusammensetzung ; Broiler
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Mit steigender Aufnahme erhöht sich der Körperfettgehalt und der Körperproteingehalt nimmt ab. Es wird oft angenommen, daß jede Zunahme im Ansatz mit mehr Fett und weniger Protein verbunden ist. Experimentelle Ergebnisse widerlegen jedoch diese Annahme. In zwei Experimenten mit männlichen Broilerhühnern wurden die Tiere auf einem Niveau von 60 % und 100 % der empfohlenen Energieaufnahme gefüttert. Die Körperzusammensetzung bei 1500 g zeigte, wie erwartet, daß sich bei steigenden Aufnahmen der Körperfettgchalt vergrößert und der Körperproteingehalt abnimmt. Fettund Proteinansatz waren linear mit der totalen Energieretention (ER) korreliert. Das bedeutet, daß jede Zunahme im Ansatz den gleichen Protein- und Fettgehalt besitzt. Wenn der Fettansatz gleich Null ist wird nur Protein, etwa 50 % des maximalen Ansatzes, retiniert. Wenn ER=O ist, wird Protein angesetzt und Fett mobilisiert. Energie-und N-Bilanzuntersuchungen bestätigen die konstante Zusammensetzung jeder Vergrößerung des Ansatzes. Die Ergebnisse beider Experimente zeigen, daß die ER aus zwei Komponenten besteht: einem basalen konstanten täglichen Proteinansatz und einer variablen zusätzlichen ER, die hauptsächlich aus Fett besteht. Der basale Proteinansatz beträgt etwa 50 % des maximalen Ansatzes. Mit steigenden Energieaufnahmen wird der basale Proteinansatz mit einer zusätzlichen Menge von Protein und Fett im konstanten Verhältnis ergänzt.
    Notes: Summary With increasing intakes the body fat content increases and that of protein decreases. It is most often assumed that this is brought about because each increment in retention contains more fat and less protein. Experimental results, however, showed that this explanation is not true. In two experiments male broiler chickens were fed at levels between 60 and 100 % of recommended energy intake. Body composition at 1500 g showed, as expected, that with increasing intakes body fat content increased and protein content decreased. Both fat and protein retention per day were linearly related to total energy retention (ER). This means that each increment in retention has the same protein and fat content. At zero fat retention only protein was retained, about 50 % of maximal retention. At zero ER protein was retained and fat mobilized. Energy and N balance experiments confirmed the constant composition of each increment in retention. The results of both experiments show that total ER consisted of two components: a basic constant daily protein retention and a variable additional ER, mainly consisting of fat. The basic protein retention is about half of maximal retention. With increasing energy intakes the basic protein retention is combined with an additional amount of protein and fat in a constant ratio.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 36 (1997), S. 332-335 
    ISSN: 1436-6215
    Keywords: Nutrient intake ; protein metabolism ; protein synthesis ; growth ; energy expenditures ; Nährstoffaufnahme ; Proteinstoffwechsel ; Proteinsynthese ; Wachstum ; Energieaufwand
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Eine Zunahme von fettfreiem Gewebe tritt auf, wenn die Proteinsynthese größer ist als der Proteinabbau. Obwohl während des Wachstums von der Geburt bis zur Reife die absoluten Proteinsynthese- und -abbauraten ansteigen, nehmen dagegen die fraktionellen Raten ab. Bcide Prozesse reagieren auf die Nährstoffaufnahme. Es gibt aber deutliche Unterschiede zwischen den verschiedenen Geweben. Protein, Kohlenhydrate und Fett können den Proteinansatz bei unreifen Tieren und Kindern stimulieren. Die zugrundeliegenden Mechanismen und die Energieaufwendungen scheinen jedoch unterschiedlich zu sein.
    Notes: Summary Lean tissue growth occurs when the rate of protein synthesis exceeds the rate of protein breakdown. Althoughabsolute rates of protein synthesis and breakdown rise during growth from birth to maturityfractional rates fall. Both these processes are sensitive to nutrient intake but responses to feeding vary greatly amongst different tissues. Protein, carbohydrate and fat can all stimulate body protein accretion in immature animals and in children but the mechanisms by which they do so, and the energy expenditures involved, seem to be different.
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  • 5
    Electronic Resource
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    Empirical economics 24 (1999), S. 23-44 
    ISSN: 1435-8921
    Keywords: Key words: Cointegration ; convergence ; growth ; Kalman filter ; JEL classifications: C22 ; O47 ; O57
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract. Augmented Dickey Fuller (ADF) and Kalman filter convergence tests are applied to annual GDPs per head to 16 industrialised countries from 1890 to 1989. Results favour convergence towards the US with a structural break following the Second World War. Estimates suggest that steady-states were higher after the war and that speeds of convergence are different across countries. The Kalman filter method dismissed the no convergence hypothesis more often than its ADF counterpart. This could explain the apparent contradiction in earlier empirical work on similar data sets (cross-section methods tended to favour convergence while time series methods were unable to dismiss the no convergence hypothesis.)
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  • 6
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    Entomologia experimentalis et applicata 80 (1996), S. 141-144 
    ISSN: 1570-7458
    Keywords: Polygonia c-album ; Nymphalidae ; host-plant selection ; growth ; size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 7
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    Entomologia experimentalis et applicata 80 (1996), S. 163-165 
    ISSN: 1570-7458
    Keywords: olfaction ; EAG ; sensory physiology ; antennal sensitivity ; interspecies hybrids ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 8
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    Entomologia experimentalis et applicata 91 (1999), S. 359-368 
    ISSN: 1570-7458
    Keywords: Barbarea vulgaris ssp. arcuata ; Cruciferae ; Phyllotreta nemorum ; Chrysomelidae ; Alticinae ; flea beetle ; plant defence ; host plant range ; near-isogenic ; Y-linkage ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A Y-linked gene (R-gene) in the flea beetle Phyllotreta nemorum L. (Coleoptera: Chrysomelidae: Alticinae) confer the ability of larvae to survive on types of the plant Barbarea vulgaris R.Br. (Brassicaceae) which are immune to attack by susceptible conspecifics. Two near-isogenic flea beetle lines were developed. The YE-line contained the Y-linked R-gene, and male larvae from this line survived on B. vulgaris. The ST-line did not contain the gene and did not survive on the plant. The YE-line had been developed through 8–9 generations of backcrosses (YE-males with ST-females) and the two lines were considered to be isogenic except for genes located on the Y-chromosome. A single copy of the Y-linked gene is sufficient to transfer a susceptible genotype (ST) into a resistant genotype (YE) which is able to utilize a plant that is immune to attack by specimens without R-genes. The Y-linked gene had no effects on survival on other plant species tested. The gene did not have any effect on developmental times and weights of adult beetles reared on other plants than B. vulgaris. Developmental times of larvae with the Y-linked gene were longer on B. vulgaris than on normal host plants, R. sativus and S. arvensis, but the adults obtained the same size on these plant species. No trade-offs of the Y-linked gene were discovered. The results suggest that the occurrence of the Y-linked gene is a derived trait which has enabled the flea beetle to expand its host plant range. The evolution of a host shift to B. vulgaris seems not to be favoured by the presence of this single gene.
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  • 9
    ISSN: 1570-7458
    Keywords: amylase inhibitor ; red kidney bean ; hard red winter wheat ; growth ; insects ; beetles ; plant resistance ; stored products ; protease inhibitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Insect α-amylase inhibiting and/or growth inhibiting activities of proteinaceous inhibitors from red kidney bean (Phaseolus vulgaris) and hard red winter wheat (Triticum aestivum) were examined. The bean inhibitor was most effectivein vitro against α-amylases from the red flour beetle (Tribolium castaneum) and the confused flour beetle (T. confusum), followed by those from the rice weevil (Sitophilus oryzae) and yellow mealworm (Tenebrio molitor). The insect enzymes were from two- to 50-fold more susceptible than human salivary α-amylase. When the inhibitors were added at a 1% level to a wheat flour plus germ diet, the growth of red flour beetle larvae was slowed relative to that of the control group of larvae, with the bean inhibitor being more effective than the wheat inhibitor. Development of both the red flour beetle and flat grain beetle (Cryptolestes pusillus) was delayed by 1% bean inhibitor, but development of the sawtoothed grain beetle (Oryzaephilus surinamensis) and lesser grain borer (Rhyzopertha dominica) was not affected by either the bean or wheat inhibitor at the 1% level. Rice weevil adults fed a diet containing 1% bean or wheat inhibitor exhibited more mortality than weevils fed the control diet. When the wheat amylase inhibitor was combined with a cysteine protease inhibitor, E-64, and fed to red flour beetle larvae, a reduction in the growth rate and an increase in the time required for adult eclosion occurred relative to larvae fed either of the inhibitors separately. The bean inhibitor was just as effective alone as when it was combined with the protease inhibitor. These results demonstrate that plant inhibitors of insect digestive enzymes act as growth inhibitors of insects and possibly as plant defense proteins, and open the way to the use of the genes of these inhibitors for genetically improving the resistance of cereals to storage pests.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 86 (1998), S. 175-182 
    ISSN: 1570-7458
    Keywords: Aleyrodidae ; greenhouse whitefly ; nitrogen ; host selection ; oviposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tomato plants, Lycopersicon esculentum Miller cv 'Tres Cantos', were supplied with high (308 ppm), medium (140 ppm) and low (84 ppm) nitrogen doses in order to determine the influence of nitrogen fertilization on feeding and oviposition site selection by greenhouse whitefly adults, T. vaporariorum (Westwood). The nitrogen and water content was higher in plants supplied with 308 N ppm than in plants with medium or low nitrogen doses and no differences were found in soluble sugar content. The leaves of the upper plant stratum (leaves 1–5) had the greatest nitrogen and water content, independent of the nitrogen dose applied. The plants were exposed to T. vaporariorum adults into a greenhouse under two current (late autumn-winter and spring-early summer) situations of the tomato crop in the Mediterranean area. The distribution of whitefly adults on the plants was affected by the nitrogen dose in both experimental conditions, the number of adults was higher on the plants supplied with high nitrogen dose. Within plants, adult distribution was affected by leaf position, the upper plant stratum being preferred for feeding. Whitefly females selected for oviposition and laid more eggs on plants and leaves of plants with higher nitrogen and water contents. We conclude that whitefly host selection for feeding and ovipositing are related to differences in nitrogen and water content of the host plant.
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  • 11
    ISSN: 1570-7458
    Keywords: fecundity ; host plant quality ; Pistia stratiotes ; Spodoptera pectinicornis ; nitrogen ; trichomes ; oviposition ; biological control of weeds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We determined the influence of larval host quality of the floating aquatic weed Pistia stratiotes L. (Araceae) on the fecundity and egg distribution of the biological control agent Spodoptera pectinicornis (Hampson) (Lepidoptera: Noctuidae). Different nutritional levels were produced by growing plants with relatively low and high levels of nitrogen, phosphorus and potassium fertilizer. Female and male pupal biomass were significantly greater when the larvae were fed leaves from the high fertilizer plants. Although the fertilizer treatments did not significantly influence total fecundity, there was an indirect effect as adults from larger pupae were more fecund. Regardless of treatment, ovipositing females formed a depression in the leaf surface by removing trichomes into which they deposited the egg masses. Most of the egg masses were laid on the lower leaf surface, on leaf positions 5–8 (counting from the young inner to the outer leaves) and during days 1–2 post-eclosion. Most of the eggs were laid in masses but about 12% were solitary. Females fed the low fertilizer treatment laid a greater proportion (mean ± s.e.) of their eggs as solitary eggs (17.3 ± 3.4% of total eggs) than did females fed the high fertilizer treatment (8.3 ± 2.3% of total eggs). The increased percentage of solitary eggs laid by the females from the low quality larval diet may be an adaptive response to decrease competition among the progeny.
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  • 12
    Electronic Resource
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    Acta biotheoretica 33 (1984), S. 35-50 
    ISSN: 1572-8358
    Keywords: Evolution ; falsification ; Darwinism ; philosophy of science
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this paper we discuss the epistemological positions of evolution theories. A sharp distinction is made between the theory that species evolved from common ancestors along specified lines of descent (here called “the theory of common descent”), and the theories intended as causal explanations of evolution (e.g. Lamarck's and Darwin's theory). The theory of common descent permits a large number of predictions of new results that would be improbable without evolution. For instance, (a) phylogenetic trees have been validated now; (b) the observed order in fossils of new species discovered since Darwin's time could be predicted from the theory of common descent; (c) owing to the theory of common descent, the degrees of similarity and difference in newly discovered properties of more or less related species could be predicted. Such observations can be regarded as attempts to falsify the theory of common descent. We conclude that the theory of common descent is an easily-falsifiable & often-tested & still-not-falsified theory, which is the strongest predicate a theory in an empirical science can obtain. Theories intended as causal explanations of evolution can be falsified essentially, and Lamarck's theory has been falsified actually. Several elements of Darwin's theory have been modified or falsified: new versions of a theory of evolution by natural selection are now the leading scientific theories on evolution. We have argued that the theory of common descent and Darwinism are ordinary, falsifiable scientific theories.
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  • 13
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    Acta biotheoretica 46 (1998), S. 141-156 
    ISSN: 1572-8358
    Keywords: locomotion ; Squamata ; lizards ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In lower quadrupedal vertebrates locomotor efficiency seems to result from the associate movements of the axial and appendicular systems, which are totally independent in structure and embryological origin. The curvature of the trunk, produced by a standing wave, magnifies the propulsive action of the limbs. In intermediate forms, the association of an elongate trunk with limbs reduced in size brings about functional consequences which may be noticeably diverse according to the degree of trunk elongation and limb reduction. According to environmental constraints, animals search for better locomotor efficiency, which implies the maintenance or breakage of this association of both locomotor systems. In some cases, limb action on the ground is added to the axial wave action through a perfect mutual adjustment of rhythmic activity, until mechanical inefficiency of the limbs is reached by possible loss of contact with the ground. In other cases, the limbs dragged on the ground during the stance phase act against the axial action or, on the contrary, are inhibited by the axial system. A review of available data tries to contribute to an understanding of the respective roles of both systems in the transition to limblessness.
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  • 14
    ISSN: 1570-7458
    Keywords: Bemisia argentifolii ; Encarsia formosa ; poinsettia ; parasitoids ; nitrogen ; tri-trophic level interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract More wasps of Encarsia formosa Gahan (Hymenoptera: Aphelinidae) were found on fertilized poinsettias, Euphorbia pulcherrima (Willd.) (Euphorbiaceae), than on non-fertilized plants. Parasitization of Bemisia argentifolii Bellows & Perring (Homoptera: Aleyrodidae) by E. formosa was higher on plants treated with calcium nitrate than with ammonium nitrate or on control plants. In a no-choice test, host feeding by E. formosa was higher when hosts were on fertilized plants than when hosts were on control plants. The nitrogen content of whitefly pupae reared on plants treated with ammonium nitrate was higher than those on calcium nitrate-treated plants. Variability in the parasitization of B. argentifolii by E. formosa appears to be due to host plant-mediated differences in the whiteflies. E. formosa may be influenced by the nutritional suitability of the host, which influences whether wasps continue to oviposit, feed, or disperse.
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  • 15
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    Entomologia experimentalis et applicata 79 (1996), S. 335-344 
    ISSN: 1570-7458
    Keywords: alkaloid ; developmental time ; early instars ; growth ; Manduca sexta ; molting duration ; phenolics ; plant-herbivore interactions ; thermal regime
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To understand the mechanisms underlying plant-insect herbivore interactions, it is necessary to examine the simultaneous effects of temperature, food quality and larval age. We examined the simultaneous effects of three allelochemicals (tomatine, rutin and chlorogenic acid) on the performance of first and second instar Manduca sexta larvae under two representative thermal regimes 21 : 10°C and 26 : 15°C for spring and summer, respectively. Thermal regime and allelochemicals interacted to influence the time from egg hatch to ecdysis to the third instar. On average, it took about half as much time to reach the third instar at 26 : 15°C as it did at 21 : 10°C. Separately, tomatine and rutin had a negative effect on developmental time from egg hatch to the third instar, but their simutaneous effects were not additive. Chlorogenic acid significantly reduced the negative effect of tomatine. The magnitude of the allelochemical effect was larger at the cooler thermal regime compared to the warmer regime. For instance, chlorogenic acid by itself had no effect at the 26 : 15°C regime, but at the 21 : 10°C regime it significantly shortened total developmental time. The effect of chlorogenic acid on stadium duration was distinctly different for the two instars. Chlorogenic acid shortened stadium duration of first instar larvae. However, depending on thermal regime and the presence of tomatine, chlorogenic acid had a negative, positive or neutral effect on stadium duration of second instar larvae. Molting duration of second instar larvae was shortened by a half day at the warmer thermal regime but was not affected by the allelochemicals. Final larval weight was influenced by rutin and chlorogenic acid. Caterpillars fed diets containing 20 μmoles of rutin were on average 10% lighter than those fed plain diet, whereas those fed diets containing 20 μmoles of chlorogenic adic were on average 7% heavier. However, the effect of chlorogenic acid depended on thermal regime. Overall, our results indicated that: 1) temperature and food quality can interact to influence insect performance and 2) these effects are influenced by larval age.
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  • 16
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    Entomologia experimentalis et applicata 80 (1996), S. 7-13 
    ISSN: 1570-7458
    Keywords: host-plant selection ; sensory physiology ; neural coding ; deterrents ; peripheral interactions ; receptor sites ; genetics of insects ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recent advances in our understanding of the relationship between chemosensory and behavioural responses to phytochemicals come from a number of studies on ovipositional and food selection behaviour of flies, butterflies, moths and beetles. Establishing input-output relationships has provided insight into the way in which the activity of chemoreceptors is translated into host-plant selection behaviour. This was achieved for both the qualitative contrast acceptance/rejection and for quantifiable preference hierarchies. By now it is clear that the subtlety of coding the complex phytochemical profiles offered by potential host plants relies on across-fibre patterns or ensemblefiring of taste neurons. Progress along these lines depends on unravelling processing pathways in the central nervous system, still a largely unexplored area in herbivorous insects. Increased interest can be noted for the mechanisms operating during the most peripheral events of chemoreception: the interaction of phytochemical and chemoreceptor, determining the specificity of recognition. Evidence for ‘peripheral integration’ has accumulated. Deterrent receptors have an especially puzzling nature. Although such cells respond to a wide array of structurally diverse secondary plant metabolites, their sensitivity profile differs between closely related species. To what extent membrane-bound receptor molecules are involved and what degree of specificity is conferred by these, is largely unknown. Sensitivity to a certain group or class of compounds is determined by single genes in several cases. This allows for a scenario in which single gene mutations affect stimulus-receptor interactions, which might concurrently affect host-plant selection behaviour.
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  • 17
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    Entomologia experimentalis et applicata 80 (1996), S. 320-324 
    ISSN: 1570-7458
    Keywords: multitrophic interactions ; phylogeny ; evolution ; fitness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 18
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    Entomologia experimentalis et applicata 80 (1996), S. 443-451 
    ISSN: 1570-7458
    Keywords: beta-carboline alkaloid ; Trichoplusia ni ; harmane ; harmaline ; amitriptyline ; imipramine ; monoamine oxidase inhibitor ; tricyclics ; growth ; feeding behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this study we investigated the effects of two naturally occurring beta-carboline alkaloids and two synthetic tricyclic antidepressants on the growth and food consumption of fifth instar larvae of the cabbage looper, Trichoplusia ni Hübner (Lepidoptera: Noctuidae). In artificial diets at high concentrations (3,000 ppm), harmane, amitriptyline, and imipramine reduce growth and feeding; harmane reduced feeding consistently at a lower concentration (200 ppm). In animals other than insects, beta-carboline alkaloids inhibit monoamine oxidase (MAO) activity and thus affect rates of disposition of serotonin and other monoamine neurotransmitters. Because brain serotonin levels are associated with variation in rates of carbohydrate and protein intake in insects, the effects of beta-carboline alkaloid ingestion on dietary self-selection behavior were examined. Choosing between diets lacking carbohydrate but containing protein and diets lacking protein but containing carbohydrate, larvae consumed a greater proportion of diet containing protein but lacking carbohydrate in the presence of harmane than in its absence. These results are consistent with beta-carboline alkaloid-mediated persistence of serotonin in the brain due to MAO inhibition. Alternatively, these results could reflect alkaloid-mediated peripheral inhibition of sucrose taste receptors influencing ingestive behaviors. That beta-carboline alkaloid ingestion is associated with changes in feeding behavior is consistent with a possible defensive role for these compounds in plant foliage.
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  • 19
    ISSN: 1570-7458
    Keywords: Brassica rapa ; B. juncea ; consumption rate ; glucosinolates ; growth rate ; indolyl ; isothiocyanate ; Mamestra configurata ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mamestra configurata (Walker) (Lep., Noctuidae) larvae were fed excisedBrassica juncea (commercial brown mustard) orB. rapa cv. Tobin (Canola) foliage of three plant growth stages-rosette (stage 2), stem elongation (stage 3) and flowering (stage 4). Relative consumption rates (RCRi) were not significantly different between the plant species. Within theB. juncea treatments, there were no significant growth stage differences in RCRi. However, withinB. rapa, RCRi increased with advancing plant growth stage. Larvae fedB. juncea foliage had significantly reduced relative growth rates (RGRi) compared to larvae fedB. rapa foliage. Within theB. juncea treatments, RGRi decreased with advancing plant growth stage. There were no significant growth stage differences in RGRi in theB. rapa treatments. RGRi was inversely proportional to the levels of isothiocyanate-releasing glucosinolates in theB. juncea treatments. RCRi was inversely proportional to the levels of indolyl glucosinolates in theB. rapa treatments. Levels of total phenols and catechols inB. juncea did not show any trend which could be related to growth stage effects in the insect nutritional indices. InB. rapa, levels of phenols and catechols in stage 3 and 4 foliage were lower than that of stage 2 foliage. Analyses of total nitrogen in field-grown plants showed reductions in percent nitrogen from rosette to flowering stage foliage. The response ofM. configurata to different growth stages of its host plants are discussed in relation to changing levels of allelochemicals and nitrogen.
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  • 20
    ISSN: 1570-7458
    Keywords: insect endocrinology ; ecdysone ; juvenile hormone ; reproduction ; growth ; inhibin ; oostatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The first insect folliculostatic peptide was isolated from vitellogenic ovaries of the mosquitoAedes aegypti. This decapeptide directly inhibits trypsin biosynthesis in the gut, and indirectly ovarian development. The factor was named Trypsin Modulating Oostatic Factor or TMOF by its discoverers. From the fleshfly Neobellieria bullata 2 folliculostatins have been isolated, the hexapeptide Neb-TMOF and the 19-mer Neb-colloostatin. The available data suggest that at least 2 of the 3 folliculostatins originate from matrix (like) proteins present in the ovary, a hitherto unknown source of hormones. Furthermore, one of the folliculostatins (Neb-TMOF) is a potent inhibitor of ecdysone biosynthesis by larval ring glands of fleshflies. The discovery of the dipteran folliculostatins, which do not show any resemblance to inhibins of vertebrates, may significantly contribute to a better understanding of the hormonal control of growth in insects and perhaps, in other animals as well. None of the 3 folliculostatins is blocked at its N- or C-terminus. This, in combination with the pleiotropy of their effects and the narrow species specificity make such peptides prime candidates for, testing their potential in insect pest control by means of molecular biological methods.
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    Entomologia experimentalis et applicata 92 (1999), S. 205-216 
    ISSN: 1570-7458
    Keywords: Samea multiplicalis ; Spodoptera pectinicornis ; Pistia stratiotes ; waterlettuce ; nitrogen utilization efficiency ; compensatory feeding ; nitrogen ; biological control of weeds
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    Notes: Abstract Compensatory responses of caterpillars fed low quality food include increased consumption and utilization of essential nutrients. Information about an insect's responses to nutritional challenges from their host plants could benefit weed biological control efforts in the selection and establishment of new agents. The target weed, Pistia stratiotes L. (Araceae) is a floating aquatic plant that has relatively low nitrogen levels which are further diluted with high water content. Efforts to establish the insect Spodoptera pectinicornis (Hampson) (Lepidoptera: Noctuidae) for biological control of P. stratiotes could benefit by examining the nutritional responses of a similar widely established lepidopteran species, Samea multiplicalis (Guenèe) (Lepidoptera: Pyralidae). Larvae of this species were fed leaves of P. stratiotes plants that had been fertilized (NPK) at high and low rates. The leaves of the fertilized plants had a 4.3-fold increase in nitrogen (dry weight) and a 1.6-fold increase in water content. The results suggest that no compensatory increases occurred in larvae fed leaves from the low fertilized plants as no changes were found in fresh mass consumption or nitrogen utilization efficiency. Consequently, development time from second-third instars to pupation was delayed about 3 days compared with larvae fed the high nitrogen leaves. Furthermore, consumption of nitrogen was only 30% and its accumulation into larval tissues was only 60% compared with the larvae fed the high fertilized leaves. The resulting larvae had both a final biomass and a growth rate that were reduced by 40%. Regardless of plant fertilizer level, the larvae fed at a rate 5–10 times greater than that of similar lepidopteran species consuming either low or high quality diets, suggesting that the S. multiplicalis larvae may be functioning at their biological limit for ingesting food.
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    Entomologia experimentalis et applicata 91 (1999), S. 29-35 
    ISSN: 1570-7458
    Keywords: chemoreception ; deterrents ; Pieris ; Brassicaceae ; cardenolides ; host-plant selection ; evolution
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    Notes: Abstract Pieris butterflies (Lepidoptera: Pieridae) are specialist herbivores of cruciferous plants. They exploit glucosinolates, secondary plant metabolites chemotaxonomically characteristic for this plant family, as token stimuli. In addition to particular glucosinolates, some genera of the Cruciferae contain cardenolides, steroidal allelochemicals that act as potent feeding and oviposition deterrents to several Pieris species. We investigated the sensory mechanisms by which these compounds are perceived in larvae. Pieris caterpillars and many other lepidopterous species are endowed with so-called generalist deterrent receptors, that respond to a broad spectrum of secondary plant substances. In Pieris caterpillars we found a second type of deterrent chemoreceptor in maxillary styloconic taste sensilla. This neuron is very sensitive to cardenolides (threshold 0.1–0.3 μM). The generalist deterrent receptor also responds to these substances but its threshold lies at 50–100× higher concentrations. In behavioural preference experiments Pieris brassicae L. caterpillars preferred cardenolide-treated cabbage leaf discs when confronted with a choice between them and a deterrent substance that does not occur in the Brassicaceae. The cardenolides acted as potent deterrents when offered against untreated cabbage leaf discs. This demonstrates that the balance of activity elicited in the two types of deterrent chemoreceptors determines the behavioural decision.
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    Acta biotheoretica 30 (1981), S. 79-102 
    ISSN: 1572-8358
    Keywords: evolution ; modifier theory ; dominance evolution
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    Notes: Abstract The problem of modifier evolution was examined with regard to the idea that modifier evolution can be considered as a result of selection for adaptation speed in populations far from equilibrium. This kind of selection was called ‘feedback selection’ in order to emphasize the difference to theories which consider modifier evolution near the equilibrium. The basic principles of this kind of selection are derived for asexual populations and the problem of dominance is discussed in the light of this concept. In general the results support the view, that the genetic properties of a character are selected along with the character itself.
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  • 24
    ISSN: 1572-8358
    Keywords: Animal cognition ; Evolution ; Representation ; Computation ; Significance ; Phenomenology ; Autonomy
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    Notes: Abstract A distinction is made between two definitions of animal cognition: the one most frequently employed in cognitive sciences considers cognition as extracting and processing information; a more phenomenologically inspired model considers it as attributing to a form of the outside world a significance, linked to the state of the animal. The respective fields of validity of these two models are discussed along with the limitations they entail, and the questions they pose to evolutionary biologists are emphasized. This is followed by a presentation of a general overview of what might be the study of the evolution of knowledge in animals.
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    Acta biotheoretica 47 (1999), S. 29-40 
    ISSN: 1572-8358
    Keywords: Sexual selection ; mate selection ; gamete selection ; evolution ; ploidy ; asssortative mating
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    Notes: Abstract Results of an agent-based computer simulation of the evolution of diploid sexual organisms showed that several mate selection strategies confer much higher average fitness to the simulated populations, and higher evolutionary stability to the alleles coding for these strategies, than random mating. Strategies which select for 'good genes' were very successful, and so were strategies based on assortative mating. The results support the hypothesis that mating is not likely to be random in nature and that the most successful mate selection strategies are those based on assortative mating or on advantageous genes.
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  • 26
    ISSN: 1570-7458
    Keywords: Coleoptera ; bruchidae ; anesthesia ; carbon dioxide ; nitrogen ; cold ; oviposition and mating
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    Notes: Abstract The effect of anesthetizing with carbon dioxide, nitrogen, or low temperature on the reproductive behavior and fecundity of Callosobruchus subinnotatus was investigated. Males and females anesthetized with N2 as virgins had shorter recovery time, copulated earlier, and had shorter mating time than those subjected to CO2 or low temperature. Exposure of males and females to 2.0±0.5 °C for 10 min had the most profound effect on the recovery periods, copulation time, and duration of mating. Adults anesthetized with CO2 and low temperature laid fewer eggs than those anesthetized with N2. Females were more affected than males by the treatments, except when males were chilled for 10 min, and this prolonged the time for commencement of mating. The mode of anesthesia could affect egg production because vitellogenesis and choriogenesis take place in the imago stage of bruchids.
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    Entomologia experimentalis et applicata 82 (1997), S. 37-44 
    ISSN: 1570-7458
    Keywords: Barbarea vulgaris ; Cruciferae ; Phyllotreta nemorum ; Chrysomelidae ; Alticinae ; flea beetle ; plant defence ; genetics ; sex-linkage ; X- and Y-chromosome ; evolution
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    Notes: Abstract A polymorphism in host plant exploitation has been discovered in the flea beetle, Phyllotreta nemorum L. (Coleoptera: Chrysomelidae: Alticinae) where one resistant population is able to use Barbarea vulgaris R.Br. ssp. arcuata (Opiz.) Simkovics (Brassicaceae) as a host plant while a susceptible population is not. Crosses (F1, F2, and backcrosses) between the two flea beetle populations were made, and survival of the progeny on B. v. ssp. arcuata was measured. The ability of P. nemorum larvae to survive in this plant species depended on the presence of major, dominant genes (R-genes). The two most abundant R-genes in the resistant flea beetle population were X- and Y-linked, respectively. The use of B. v. ssp. arcuata as a natural host plant by the resistant population of P. nemorum seems to be an extension of the host plant range of the species. The role of sex-linked genes in the evolution of host range is discussed.
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    Entomologia experimentalis et applicata 82 (1997), S. 25-35 
    ISSN: 1570-7458
    Keywords: Barbarea vulgaris ; Cruciferae ; Phyllotreta nemorum ; Chrysomelidae ; Alticinae ; flea beetle ; plant defence ; resistance ; host plant ; variation ; evolution
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    Notes: Abstract Several sorts of variation in the interaction between the insect, Phyllotreta nemorum L. (Coleoptera:Chrysomelidae:Alticinae), and the plant, Barbarea vulgaris R.Br. (Brassicaceae), have been discovered: 1) genetic differences in the levels of defences in the plant, 2) genetic differences in the ability of insects to cope with the plant defences, 3) seasonal variation in levels of defences in the plant, and 4) differences between leaf types in levels of defences. Two plant accessions were suitable for larval development throughout the season while the remaining nine accessions were more or less unsuitable for larvae from the ‘susceptible’ T-population at least at certain times of the year. All accessions were suitable for the ‘resistant’ E-population throughout the year. There was a seasonal variation in levels of defences in some accessions which were unsuitable for the T-population during the summer period when beetles were present, but not during autumn and spring when the beetle were hibernating. Upper (younger) cauline leaves of these accessions had higher levels of defences than lower (older) cauline leaves. The resistant E-population used B. vulgaris as a natural host plant while the susceptible T-population did not. The use of B. vulgaris as a natural host plant by the E-population of P. nemorum seems to be an extension of the host plant range of the species. Variation in plant defences may have facilitated the switch in host plant use by the resistant flea beetle population.
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    Entomologia experimentalis et applicata 77 (1995), S. 205-210 
    ISSN: 1570-7458
    Keywords: nitrogen ; maize ; lepidopterous stem and cob borers ; Sesamia calamistis ; Eldana saccharina ; Mussidia nigrivenella ; Cryptophlebia leucotreta ; dead hearts ; stem tunneling ; yields
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    Notes: Abstract The influence of four nitrogen levels (0, 60, 90 and 120 kg N/ha) on growth of maize and development of lepidopterous pests was investigatdd in a field trial. Nitrogen had a positive effect on both plant growth variables (plant height, stem diameter and yield), and development and survival ofSesamia calamistis andEldana saccharina, and thereby increased the incidence of dead hearts and stem tunneling. However, the percent yield loss due to artificial infestation decreased with increasing N application rate from 20% to 11% in the in the 0kg/ha and 120kg/ha treatment, respectively. Using a multiple regression analysis, plant height, plant diameter and stem tunneling were found to be the most important variables explaining the variability in maize yield.
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    Entomologia experimentalis et applicata 92 (1999), S. 165-177 
    ISSN: 1570-7458
    Keywords: Chrysomelidae ; herbivory ; Asteraceae ; life history ; nitrogen ; plant quality ; season
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    Notes: Abstract Phytophagous insects which feed on the leaves of herbaceous host plants have to adapt their life histories to the fact that protein nitrogen is usually highest in growing tissues in spring. We monitored field populations of larvae and adults of three chrysomelid species (Galeruca tanaceti (L.) (main host Achillea millefolium (L.) Yarrow), Cassida rubiginosa (Mueller) (main host Cirsium arvense (L.) Scop.) and Oreina luctuosa (Suffrian) (host Centaurea scabiosa (L.)) together with the amount of protein nitrogen of their food resources and host plant biomass. As expected, the development of host quality, measured as concentration of protein nitrogen, and host plant biomass showed inverse trends during the season. The euryphagous G. tanaceti attacks Achillea early and profits from high nitrogen concentrations in the leaves. Occasional overexploitations of local populations of Achillea are compensated by the capacity to move to other host species. In C. rubiginosa, a species with a host range restricted to the Cardueae, the main larval feeding activity is postponed to a period when the nitrogen content of the host leaves had dropped to 50% of its initial value, but when host plant biomass had increased by 30%. In the monophagous O. luctuosa the larval development is synchronized with a still later phase of host phenology, at which the nitrogen content is below 50% but plant biomass has reached its maximum. There seem to be selection factors, which oppose the use of high quality food in spring and which force the latter two species to postpone their larval development to a later time in the year. This could be caused by numerous factors like, for example, mean daytime temperature. Later in the season the larvae have to cope with the low quality of their host plants. They have, however, the advantage of large quantities of food available. A laboratory study with adults and mature larvae of O. luctuosa shows that this species can overcome low levels of protein nitrogen either by selecting younger leaves with higher nitrogen concentrations or by increasing the daily food consumption rate (RCR) on leaves with a low level of nitrogen and by a prolongation of the feeding period. In this way the larvae compensate the effect of lower daily growth rates (RGR) and a lower food conversion index (ECI) on poor food quality: Regardless of the level of protein nitrogen there was no statistically significant difference in total gain of weight during the third-instar feeding period and in the weight at the end of the third larval stage. The three investigated chrysomelids show that there exists a broad spectrum of adaptations to overcome the dilemma of variable food quality.
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  • 31
    ISSN: 1572-8927
    Keywords: Supersaturation ; nitrogen ; cosolvent ; cetyltrimethylammonium bromide
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    Topics: Chemistry and Pharmacology
    Notes: Abstract The decomposition of ammonium nitrite in water creates a supersaturated solution of nitrogen. The same process occurs in water-organic solvent mixtures. Acetone, dioxane, dimethylsulfoxide (DMSO) and dimethylformamide (DMF) are the cosolvents used in this study. The limits of supersaturation of nitrogen (C SL /mol L−1) were determined in all of these solvent mixtures by releasing the dissolved gas sonicationally and measuring the volume of released gas. C SL was generally increased in the presence of cosolvents. The effectiveness sequence of organic solvents was found to be as DMF〈DMSO〈Dioxanet≅Acetone. Transportation period of small bubbles formed during sonication is changed by compositions of solvent mixtures. These periods may depend on the viscosity of the solution. Effects of the presence of cetyltrimethylammonium bromide were also studied. It was concluded that there may be a relation between the strength of the watercosolvent H-bonds and C SL and all of the measured quantities of this study were generally affected by micelle formation.
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    Journal of solution chemistry 4 (1975), S. 523-534 
    ISSN: 1572-8927
    Keywords: Salting coefficient ; scaled-particle theory ; gas solubilities ; seawater ; helium ; neon ; argon ; oxygen ; nitrogen
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    Topics: Chemistry and Pharmacology
    Notes: Abstract Experimental values of the salting coefficients for He, Ne, Ar, O2, and N2 in seawater are compared with values calculated from scaled-particle theory. The agreement is reasonably good; the average difference between calculated and observed values at 25°C is 0.007. Scaled-particle theory predicts correctly thatk s should decrease as the temperature increases and that this effect should be most pronounced at low temperatures. However, the predicted magnitude ofdK s/dt is only about half of that observed.
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    Journal of insect behavior 11 (1998), S. 179-189 
    ISSN: 1572-8889
    Keywords: open-air foraging ; caste ; polyethism ; litter feeder ; nitrogen ; termite
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    Topics: Biology
    Notes: Abstract The Southeast Asian nasute termite Longipeditermes longipes forages on the open ground on leaf litter. Its monomorphic workers carry back food balls in their mandibles while dimorphic soldiers defensively surround the marching columns and the foraging patches. When mechanically disturbed, workers hide under the litter, whereas antennating soldiers face as closely as possible the source of disturbance. Foragers prefer the lower, nitrogen-rich layer of the litter. Soldier behavior and column organization (returning workers in the center lanes, outgoing workers in the two flanking lanes) are similar to those in the related genera Hospitalitermes and Lacessititermes, which, however, tend to forage above ground.
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    Journal of solution chemistry 13 (1984), S. 335-348 
    ISSN: 1572-8927
    Keywords: Solubility ; Henry's law coefficients ; Ostwald coefficients ; aqueous solutions ; nitrogen
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    Topics: Chemistry and Pharmacology
    Notes: Abstract The solubility of nitrogen in pure liquid water was measured in the pressure range 45 to 115 kPa and in the temperature range 5 to 50°C. These data are used to obtain Henry coefficients H 2,1 (T,P s,1 ) at the vapor pressure P s,1 of water. The temperature dependence of H 2,1 (T,P s,1 ) is accounted for by both a Clarke-Glew (CG) type fitting equation, and a power series in T−1, as suggested by Benson and Krause (BK). The imprecision of our measurements is characterized by an average deviation of ±0.038% from a four-term CG equation, and by an average deviation of ±0.042% from a three-term BK equation. From the temperature variation of H 2,1 (T,P s,1 ) partial molar quantities referring to the solution process, such as enthalpies and heat capacities of solution, are obtained. They are given in tabular form, together with H 2,1 (T,P s,1 ) and derived Ostwald coefficients L∞, at rounded temperatures. Finally, experimental results are compared with values calculated via scaled particle theory.
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    Catalysis letters 37 (1996), S. 163-165 
    ISSN: 1572-879X
    Keywords: nitrogen ; Rh(111) ; thermal desorption ; Arrhenius parameters ; lateral interactions ; NO decomposition
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    Topics: Chemistry and Pharmacology
    Notes: Abstract Associative desorption of N atoms from the Rh(111) surface is simulated in the framework of the lattice-gas model. The Arrhenius parameters and nearest-neighbour lateral interaction employed to describe the measured thermal desorption spectra are as follows:v=1013 s−1,E d=40 kcal/mol, and ε1=1.7 kcal/mol. The results obtained are used to clarify the role of nitrogen desorption in the NO + CO reaction on Rh(111) atT=400–700 K andP NO≈P CO≈0.01 atm.
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  • 36
    ISSN: 1433-4909
    Keywords: Key words Thermococcus ; Pyrococcus ; Thermophilic ; Phosphofructokinase ; Evolution ; ADP ; Glycolysis ; ATP
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    Topics: Biology
    Notes: Abstract The ADP-dependent phosphofructokinase (PFK) from Thermococcus zilligii has been purified 950 fold; it had a specific activity of 190 U mg−1. The enzyme required Mg2+ ions for optimal activity and was specific for ADP. The forward reaction kinetics were hyperbolic for both cosubstrates (pH optimum of 6.4), and the apparent K m values for ADP and fructose-6-phosphate were 0.6 mM (apparent V max of 243 U mg−1) and 1.47 mM (apparent V max of 197 U mg−1), respectively. Significantly, the enzyme is indicated to be nonallosteric but was slightly activated by some monovalent cations including Na+ and K+. The protein had a subunit size of 42.2 kDa and an estimated native molecular weight of 66 kDa (gel filtration). Maximal reaction rates for the reverse reaction were attained at pH 7.5–8.0, and the apparent K m values for fructose-1,6-bisphosphate and AMP were 0.56 mM (apparent V max of 2.9 U mg−1) and 12.5 mM, respectively. The biochemical characteristics of this unique ADP-dependent enzymatic activity are compared to ATP and pyrophosphate-dependent phosphofructokinases.
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  • 37
    ISSN: 1433-4909
    Keywords: Key wordsNatronomonas pharaonis ; Natronobacteria ; Archaea ; Serine protease ; Chymotrypsinogen ; Evolution
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    Topics: Biology
    Notes: Abstract A protease of a molecular mass of approximately 30 kDa was isolated and purified from the haloalkaliphilic archaeon Natronomonas (formerly Natronobacterium) pharaonis. The enzyme hydrolyzed synthetic peptides, preferentially at the carboxyl terminus of phenylalanine or leucine, as well as large proteins. Hydrolysis occurred over the range of pH from 6 to 12, with an optimum at pH 10. The temperature optimum was 61°C. The enzyme was nearly equally active over the range of salt concentration from 0.5 to 4 M (NaCl or KCl). A strong cross-reaction with a polyclonal antiserum against human chymotrypsin was observed. Enzymatic activity was inhibited by typical serine protease inhibitors. There was significant homology between N-terminal and internal sequences from autolytic fragments and the sequence of bovine chymotrypsinogen B; the overall amino acid composition was similar to that of vertebrate chymotrypsinogens. Evidence for a zymogen-like processing of the protease was obtained. Cell extracts from other halobacteria exhibited similar proteolytic activity and immunoreactivity. The data suggested a widespread distribution of a chymotrypsinogen B-like protease among halo- and haloalkaliphilic Archaea.
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    Cellular and molecular life sciences 52 (1996), S. 14-24 
    ISSN: 1420-9071
    Keywords: Lycaenidae ; Formicidae ; symbiosis ; mutualism ; parasitism ; communication ; ecology ; evolution
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    Topics: Biology , Medicine
    Notes: Abstract Associations with ants, termed myrmecophily, are widespread in the butterfly family Lycaenidae and range from mere co-existence to more or less specific mutualistic or even parasitic interactions. Secretions of specialized epidermal glands are crucial for mediating the interactions. Transfer of nutrients (carbohydrates, amino acids) from butterfly larvae to ants plays a major role, but manipulative communication with the help of odour signals is also involved. By means of myrmecophily, lycaenid butterflies largely escape ant predation, and certain species gain protection through attendant ants or achieve developmental benefits from ant-attendance. Benefits to the ants range from minimal to substantial food rewards. While most lycaenid species maintain facultative relationships with a variety of ant genera, highly specific and obligatory associations have convergently evolved in a number of butterfly lineages. As a corollary, communication systems are largely unspecific in the former, but may be highly specialized in the latter. The sophisticated communication between obligate myrmecophiles and their host ants is tightly connected with the evolutionary rise of specialized life-cycles and thus is a source of augmenting diversity within the butterflies.
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    Cellular and molecular life sciences 51 (1995), S. 454-464 
    ISSN: 1420-9071
    Keywords: Quantitative genetics ; life history ; evolution ; cladocera ; heritability ; Daphnia ; zooplankton
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    Topics: Biology , Medicine
    Notes: Abstract Quantitative genetic techniques are powerful tools for use in understanding the microevolutionary process. Because of their size, lifespan, and ease of culture, many zooplankton species are ideal for quantitative genetic approaches. As model systems, studies of zooplankton life histories are becoming increasingly used for examination of the central paradigms of evolutionary theory. Two of the fundamental empirical questions that zooplankton quantitative genetics studies can answer are: 1) How much genetic variance exists in natural populations for life history traits? 2) What is the empirical evidence for trade-offs that permeate life history theory based on optimality approaches? A review of existing data onDaphnia indicates substantial genetic variance for body size, clutch size, and age at first reproduction. Average broad-sense heritabilities for these three characters across 19 populations of 6 species are 0.31, 0.31, and 0.34, respectively. Although there is some discrepancy between the two pertinent studies that were designed to decompose the total genetic variance into its additive and non-additive components, a crude average seems to suggest that approximately 60% of the total genetic variance has an additive basis. The existing data are somewhat inconsistent with respect to presence/absence of trade-offs (negative genetic correlations) among life history traits. A composite of the existing data seems to argue against the existence of strong trade-offs between offspring size and offspring number, between present and future reproduction, and between developmental rate and fecundity. However, there is some evidence for a shift toward more negative (less positive) covariances in more stressful environments (e.g., low food). Zooplankton will prove to be very useful in future study in several important areas of research, including the genetics and physiology of aging, the importance of genotype-environment interaction for life history traits, and the evolution of phenotypic plasticity.
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    Cellular and molecular life sciences 52 (1996), S. 503-510 
    ISSN: 1420-9071
    Keywords: Drosophila ; accessory gland ; reproduction ; sexual behavior ; sperm displacement ; evolution
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    Topics: Biology , Medicine
    Notes: Abstract Recent results from biochemical and molecular genetic studies of the accessory gland proteins in maleDrosophila are reviewed. The most prominent feature is the species-specific variability. However, the analysis of the sex peptide inD. melanogaster shows that there is a strong homology in the molecular structure to the closely related sibling species, and that divergence increases with increasing phylogenetic distance. For this reason the sex peptide, after being transferred to the female genital tract during copulation, reduces receptivity and increases oviposition only in virgin females belonging to the same species group and subgroup. Even though studies were hitherto limited to a small number of the secretory components, it is evident that the accessory gland proteins play a key role in reproductive success of the fruit fly by changing female sexual behavior, supporting sperm transfer, storage and displacement. Thus, genes encoding the accessory gland proteins are apparently under strong evolutionary selection.
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  • 41
    ISSN: 1570-7458
    Keywords: Alsophila pometaria ; Geometridae ; Anisota senatoria ; Citheroniidae ; Quercus ; nutritional ecology ; herbivory ; nutritional indices ; consumption ; growth ; utilization efficiency ; nitrogen ; water ; tannins ; phenols ; gut pH ; digestive enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Alimentées sur feuillage jeune de chêne, les chenilles d'Alsophila pometaria avaient un taux relatif de croissance (RGR) et un taux relatif d'accumulation d'azote (RNAR) plus élevés que les chenilles d'Anisota senatoria alimentées sur feuillage mûr de chêne. Bien que le jeune feuillage soit plus efficacement digéré par A. pometaria (AD plus élevé), il n'est pas assimilé et utilisé pour la croissance avec de meilleurs rendements (les ECI ne sont pas différents). Ainsi le taux de croissance plus élevé d'A. pometaria est dû entièrement à un taux de consommation plus important (RCR et RNCR). Le feuillage jeune est significativement plus riche en azote et en eau que le feuillage mûr, mais les niveaux de phénol et de tanins sont les mêmes. A pometaria consomme les feuilles de différentes espèces de chênes au même taux, indépendamment de la teneur en azote, tandis que A. senatoria accroît sa consommation en réponse à une diminution de la teneur en azote. Il en résulte que le taux de croissance d'A. pometaria dépend directement de la teneur en azote des feuilles, tandis que celui d'A. senatoria en est indépendant. Les systèmes digestifs des deux insectes sont biochimiquement semblables et sont efficaces pour la digestion des protéines. Les tanins et les phénols n'influent pas sur les indices nutritionnels de ces deux espèces. Nous estimons que le principal intérêt de l'alimentation printanière est la disponibilité en feuillage succulent, riche en azote, et non l'absence de feuilles à haute teneur en tanin. L'alimentation printanière semble correspondre à une strategie alimentaire qui favorise la croissance aux dépens de l'efficacité tandis que l'alimentation en fin d'été est une stratégie qui favorise l'efficacité sur la rapidité.
    Notes: Abstract The larvae of Alsophila pometaria (Harr.), feeding on the young foliage of oak, has a higher relative growth rate (RGR) and relative nitrogen accumulation rate (RNAR) than the larvae of Anisota senatoria (J. E. Smith), feeding on the mature foliage of oak. Although the young oak foliage is more efficiently digested by A. pometaria (higher AD's), it is not more efficiently assimilated and used for growth (no difference in ECI's). Thus, the higher growth rate of A. pometaria is due entirely to a higher consumption rate (RCR and RNCR). Young foliage is significantly higher in nitrogen and water than mature foliage, but phenol and tannin levels are comparable in young and old foliage. A. pometaria consumes the foliage of different oak species at the same rate, independent of nitrogen content, while A. senatoria increases its consumption rate in response to decreased nitrogen levels. As a result, the growth rate of A. pometaria is directly related to leaf nitrogen content, while the growth rate of A. senatoria is independent of leaf nitrogen. The two species of insects have digestive systems that are very similar biochemically, and that are well-designed for effective protein digestion. Tannins and phenols do not influence the nutrional indices of either species. We suggest that the major benefit of spring feeding is the availability of succulent, high-nitrogen foliage, and not the avoidance of high-tannin foliage. The spring feeder appears to have a feeding strategy that favors rapid growth at the expense of efficiency, while the late summer feeder has a strategy that favors efficiency over rate.
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    Entomologia experimentalis et applicata 36 (1984), S. 293-295 
    ISSN: 1570-7458
    Keywords: ryegrass ; Oscinella frit ; Geomyza tripunctata ; nitrogen
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  • 43
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    BioMetals 11 (1998), S. 277-295 
    ISSN: 1572-8773
    Keywords: evolution ; classification ; EF-hand ; domain ; homology ; chimera ; congruence ; gene duplication ; gene fusion ; eukaryote ; dendrogram ; calmodulin ; troponin C ; light chain of myosin ; S100 ; parvalbumin ; calcineurin ; recoverin ; calpain ; sorcin ; diacylglycerol ; calbindin ; aequorin ; phospholipase C ; BM-40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Forty-five distinct subfamilies of EF-hand proteins have been identified. They contain from two to eight EF-hands that are recognizable by amino acid sequence as being statistically similar to other EF-hand domains. All proteins within one subfamily are congruent to one another, i.e. the dendrogram computed from one of the EF-hand domains is similar, within statistical error, to the dendrogram computed from another(s) domain. Thirteen subfamilies - including Calmodulin, Troponin C, Essential light chain, Regulatory light chain - referred to collectively as CTER, are congruent with one another. They appear to have evolved from a single ur-domain by two cycles of gene duplication and fusion. The subfamilies of CTER subsequently evolved by gene duplications and speciations. The remaining 32 subfamilies do not show such general patterns of congruence; however, some - such as S100, intestinal calcium binding protein (calbindin 9kd), and trichohylin - do not form congruent clusters of subfamilies. Nearly all of the domains 1, 3, 5, and 7 are most similar to other ODD domains. Correspondingly the EVEN numbered domains of all 45 subfamilies most closely resemble EVEN domains of other subfamilies. Many sequence and chem-ical characteristics do not show systemic trends by subfamily or species of host organisms; such homoplasy is widespread. Eighteen of the subfamilies are heterochimeric; in addition to multiple EF-hands they contain domains of other evolutionary origins.© Kluwer Academic Publishers
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  • 44
    ISSN: 1572-879X
    Keywords: adsorption ; adsorption isotherms ; dinitrogen ; FTIR spectroscopy ; geminal species ; NaY ; nitrogen ; zeolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Adsorption of N2 on NaY zeolites at 85 K and equilibrium pressures higher than 1 kPa results in the formation of geminal dinitrogen complexes characterized by an IR band at 2333.5 cm−1 (2255.4 cm−1 after adsorption of 15N2). With decreasing equilibrium pressure the complexes tend to loose one N2 ligand, thus forming linear species characterized by an IR band at 2336.8 cm−1 (2258.7 cm−1 after adsorption of 15N2). All species disappear completely after evacuation. Co-adsorption of N2 and CO revealed that the dinitrogen complexes are formed on Na+ cations. The changes in the concentrations of the linear and geminal N2 species with the changes in the equilibrium pressure are excellently described by equations of adsorption isotherms proposed earlier for mono- and di-carbonyls.
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    Minds and machines 6 (1996), S. 463-480 
    ISSN: 1572-8641
    Keywords: Human reasoning ; evolution ; deontic reasoning ; transitive reasoning ; non-human primates ; neocortical ratio ; dominance hierarchy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Philosophy
    Notes: Abstract Research from ethology and evolutionary biology indicates the following about the evolution of reasoning capacity. First, solving problems of social competition and cooperation have direct impact on survival rates and reproductive success. Second, the social structure that evolved from this pressure is the dominance hierarchy. Third, primates that live in large groups with complex dominance hierarchies also show greater neocortical development, and concomitantly greater cognitive capacity. These facts suggest that the necessity of reasoning effectively about dominance hierarchies left an indelible mark on primate reasoning architectures, including that of humans. In order to survive in a dominance hierarchy, an individual must be capable of (a) making rank discriminations, (b) recognizing what is forbidden and what is permitted based one's rank, and (c) deciding whether to engage in or refriin from activities that will allow one to move up in rank. The first problem is closely tied to the capacity for transitive reasoning, while the second and third are intimately related to the capacity for deontic reasoning. I argue that the human capacity for these types of reasoning have evolutionary roots that reach deeper into our ancestral past than the emergence of the hominid line, and the operation of these evolutionarily primitive reasoning systems can be seen in the development of human reasoning and domain-specific effects in adult reasoning.
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  • 46
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    Minds and machines 9 (1999), S. 309-346 
    ISSN: 1572-8641
    Keywords: language ; grammar ; syntax ; semantics ; evolution ; emergence ; brain size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Philosophy
    Notes: Abstract It is commonly argued that the rules of language, as distinct from its semantic features, are the characteristics which most clearly distinguish language from the communication systems of other species. A number of linguists (e.g., Chomsky 1972, 1980; Pinker 1994) have suggested that the universal features of grammar (UG) are unique human adaptations showing no evolutionary continuities with any other species. However, recent summaries of the substantive features of UG are quite remarkable in the very general nature of the features proposed. While the syntax of any given language can be quite complex, the specific rules vary so much between languages that the truly universal (i.e. innate) aspects of grammar are not complex at all. In fact, these features most closely resemble a set of general descriptions of our richly complex semantic cognition, and not a list of specific rules. General principles of the evolutionary process suggest that syntax is more properly understood as an emergent characteristic of the explosion of semantic complexity that occurred during hominid evolution. It is argued that grammatical rules used in given languages are likely to be simply conventionalized, invented features of language, and not the result of an innate, grammar-specific module. The grammatical and syntactic regularities that are found across languages occur simply because all languages attempt to communicate the same sorts of semantic information.
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  • 47
    ISSN: 1572-8757
    Keywords: kinetics ; isotope-exchange ; nitrogen ; adsorption ; methane ; zeolite ; equilibria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The Isotope Exchange Technique (IET) was used to simultaneously measure pure and binary gas adsorption equilibria and kinetics (self-diffusivities) of CH4 and N2 on pelletized 4A zeolite. The experiment was carried out isothermally without disturbing the adsorbed phase. CH4 was selectively adsorbed over N2 by the zeolite because of its higher polarizability. The multi-site Langmuir model described the pure gas and binary adsorption equilibria fairly well at three different temperatures. The selectivity of adsorption of CH4 over N2 increased with increasing pressure at constant gas phase composition and temperature. This curious behavior was caused by the differences in the sizes of the adsorbates. The diffusion of CH4 and N2 into the zeolite was an activated process and the Fickian diffusion model described the uptake of both pure gases and their mixtures. The self-diffusivity of N2 was an order of magnitude larger than that for CH4. The pure gas self-diffusivities for both components were constants over a large range of surface coverages (0 〈 θ 〈 0.5). The self-diffusivities of CH4 and N2 from their binary mixtures were not affected by the presence of each other, compared to their pure gas self-diffusivities at identical surface coverages.
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  • 48
    ISSN: 1572-879X
    Keywords: platinum ; rhodium ; alloy ; surface composition ; nitrogen ; oxygen
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    Topics: Chemistry and Pharmacology
    Notes: Abstract Two kinds of adsorbed N atoms exist on a Pt0.25Rh0.75(100) surface. One desorbs at 490 K and the other desorbs at 650 K. The former reacts with H2 at 400 K, but the latter does not. It is supposed that the adsorption of these two N atoms is responsible of the surface composition, ratio of Pt and Rh.
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  • 49
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    Entomologia experimentalis et applicata 35 (1984), S. 75-81 
    ISSN: 1570-7458
    Keywords: Nezara viridula ; insect dietetics ; growth ; fecundity ; flight capacity ; Heteroptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les effets du régime alimentaire pendant le 5ème stade sur les performances imaginales de N. viridula ont été déterminés en comparant la croissance, la fécondité, la durée du vol captif, et l'accumulation de corps gras chez des insectes élevés sur 4 régimes stérilisés. A partir de la formation des larves de 5ème stade, elles ont été alimentées sur haricots verts et arachides, ou transférées sur un régime formé exclusivement d'arachides, ou de haricots verts, ou de graines de soja ‘trempées’, cependant la durée du 5ème stade. Les insectes ont été transférés sur un régime de haricots verts et arachides à leur émergence. Les femelles élevées continuellement de haricots verts et arachides étaient plus lourdes (P〈0,01) à l'émergence (161,6 mg) que celles élevées sur haricots verts (146,3 mg) pendant le 5ème stade, et pondent plus d'oeufs (P〈0,08) pendant une durée de 34 jours (100,9 oeufs) que celles élevées sur arachides (54,7 oeufs). Plus de femelles élevées sur haricots verts et arachides (76,2%) pondent que celles élevées sur arachides (61,1%), soja ‘trempé’ (62,5%), ou haricots verts (60,9%). Les femelles élevées sur arachides volaient plus longtemps (P 〈 0,01) (42,9 mn) que celles élevées sur haricots verts (19,8 mn) pendant des vols captifs le 3ème jour après l'émergence. 78% de toutes les femelles élevées sur arachides volaient 〉-30 mn, contre 50% pour celles élevées sur haricots verts et arachides, ou soja ‘trempé’, et 35% pour celles élevées sur haricots verts. Seulement 7% des femelles élevées sur haricots verts volaient à la 60ème minute à la fin du test, contre 25% pour les femelles soja ‘trempé’, 33% pour les femelles haricots verts et arachides, et 47% pour celles élevées sur arachides. Les femelles ont été disséquées 34 jours après l'émergence pour déterminer l'importance du corps gras. Les indices de corps gras (Kiritani, 1963) montraient que les femelles élevées sur arachides (1,8) et graines de soja (1,7) ont apparemment un corps gras plus développé que celles élevées sur haricots verts et arachides (1,5), our haricots verts (1,2), pendant le 5ème stade. Ces résultats montrent que l'alimentation pendant le dernier stade larvaire de N. viridula affecte irréversiblement la croissance, la fécondité et l'aptitude au vol des femelles. En estimant que des résultats semblables auraient été obtenus avec des insectes élevés sur ces 4 aliments depuis l'éclosion, haricots verts et arachides constituent le meilleur aliment pour l'élevage de N. viridula. Ce régime fournit une graine mûre, vraisemblablement nécessaire pour l'accumulation d'un corps gras suffisant et une aptitude au vol migratoire, et une plante verte qui fournit les aliments apparement essentiels à l'ovogenèse.
    Notes: Abstract The effects of diet during the fifth stadium on performance of adult N. viridula were determined through comparing growth, fecundity, and duration of tethered flight of insects reared on four axenic diets: fresh green bean, raw-shelled peanut, a combination of the two and soaked soybean seed. Females reared on the combination diet were heavier than those reared on green beans and oviposited more than those reared on peanuts. Three-day-old adult females reared on peanuts flew longer than those reared on green beans. More females reared on diets containing mature seed showed a capacity for extended flight and had larger fat bodies at 34-days postemergence. Thus, inadequate diet during the fifth stadium irreversibly affected growth, development, reproduction and flight capacity.
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    Entomologia experimentalis et applicata 29 (1981), S. 109-116 
    ISSN: 1570-7458
    Keywords: Heteronychus arator ; Scarabaeidae ; larvae ; consumption ; utilization ; growth ; feeding ; roots ; Paspalum dilatatum ; Lolium perenne ; Trifolium repens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Futteraufnahme, die Futterverwertung und das Wachstum von Drittstadiumlarven von H. arator beim Fressen von Wurzeln von Paspalum dilatatum, Raygras (Lolium perenne) und Weissklee (Trifolium repens) wurden gravimetrisch gemessen. Der durchschnittliche Futterverzehrindex auf Gräsern war 0.65 mg/mg Larve/Woche verglichen mit 0.18 auf Weissklee. Die relative Wachstumsrate auf Paspalum und Raygras was 0.158 und 0.124 mg/mg Larve/Woche verglichen mit 0.043 auf Weissklee, was den geringen Verzehr an Weisskleewurzel widerspiegelt. Die Verwertung der gefressenen Wurzel war 22%, 18% und 24% für Paspalum, Ryagras und Weissklee. Das Fehlen gesicherter Unterschiede in der Futterverwertung der drei Pflanzenarten deutet darauf hin, dass die geringe Wachstumsrate auf Weissklee bloss durch geringe Futteraufnahme verursacht ist. Es wurde gezeigt, dass in Weisskleewurzel Frasinhibitoren für H. arator vorhanden sind. Die erhaltenen Schätzungen für Futteraufnahme durch Scarabaeiden sind die besten Daten für wurzelfressende Arten und liefern eine Basis, um den Einfluss der Weidepflanzen auf H. arator Populationen zu verstehen.
    Notes: Abstract The consumotion, utilization and growth of third-instar larvae of black beetle, Heteronychus arator (F.) feeding on roots of ryegrass (Lolium perenne), paspalum (Paspalum dilatatum) and white clover (Trifolium repens) were studied. Consumption was greater on the grasses than on white clover when assessed by gravimetric methods. Larvae had a higher growth rate on the grasses. Utilization of the roots of the three species was similar indicating that poor growth on white clover is the result of low consumption probably induced by the presence of feeding deterrents in the roots.
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    Journal for general philosophy of science 30 (1999), S. 37-58 
    ISSN: 1572-8587
    Keywords: protein ; experimentation ; conceptual variation and selection ; evolution ; Mulder ; Liebig ; Pflüger ; Nägeli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Philosophy , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract A philosophically comprehended account is given of the genesis and evolution of the concept of protein. Characteristic of this development were not shifts in theory in response to new experimental data, but shifts in the range of questions that the available experimental resources were fit to cope with effectively. Apart from explanatory success with regard to its own range of questions, various other selecting factors acted on a conceptual variant, some stemming from a competing set of research questions, others from an altogether different field of inquiry, and still others from the external environment. These results are best explained on, hence support, an evolutionary model of the progress of experimental investigation, whose outlines are briefly discussed.
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    Minds and machines 6 (1996), S. 481-505 
    ISSN: 1572-8641
    Keywords: Neuroscience ; evolutionary psychology ; interfield theory ; evolution ; teleology ; function ; functionalism ; brain mapping ; language processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Philosophy
    Notes: Abstract The idea of integrating evolutionary biology and psychology has great promise, but one that will be compromised if psychological functions are conceived too abstractly and neuroscience is not allowed to play a contructive role. We argue that the proper integration of neuroscience, psychology, and evolutionary biology requires a telelogical as opposed to a merely componential analysis of function. A teleological analysis is required in neuroscience itself; we point to traditional and curent research methods in neuroscience, which make critical use of distinctly teleological functional considerations in brain cartography. Only by invoking teleological criteria can researchers distinguish the fruitful ways of identifying brain components from the myriad of possible ways. One likely reason for reluctance to turn to neuroscience is fear of reduction, but we argue that, in the context of a teleological perspective on function, this concern is misplaced. Adducing such theoretical considerations as top-down and bottom-up constraints on neuroscientific and psychological models, as well as existing cases of productive, multidisciplinary cooperation, we argue that integration of neuroscience into psychology and evolutionary biology is likely to be mutually beneficial. We also show how it can be accommodated methodologically within the framework of an interfield theory.
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  • 53
    ISSN: 1432-1211
    Keywords: Key words Antigen processing ; Evolution ; Cell surface molecules ; Mhc ; Class I antigens
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    Topics: Biology , Medicine
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  • 54
    ISSN: 1432-1211
    Keywords: Key words NRAMP ; Fish ; Carp ; Evolution ; Expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The mouse Lsh/Ity/Bcg locus regulates natural resistance to intracellular pathogens, and the Nramp1 gene was isolated as its candidate. Nramp is part of a small family of at least two genes, Nramp1 and Nramp2. In the present study, a full-length cDNA for carp NRAMP has been isolated and characterized. Nucleotide and predicted amino acid sequence analysis indicate that the carp NRAMP encodes a 548 amino acid membrane protein with 12 putative transmembrane domains, two N-linked glycosylation sites, and an evolutionarily conserved consensus transport motif. The peptide sequence identity among carp and human NRAMP2 is 78%, and 65% with human NRAMP1. Reverse transcription-polymerase chain reaction revealed that carp NRAMP is ubiquitously expressed. Phylogenetic analysis, using neigbor-joining, showed that the carp NRAMP protein clustered together with mammalian NRAMP2 proteins.
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    Immunogenetics 50 (1999), S. 301-308 
    ISSN: 1432-1211
    Keywords: Key words T-cell receptors ; Variable region genes ; Evolution ; Phylogeny ; Diversity
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    Topics: Biology , Medicine
    Notes: Abstract  The receptor of a T lymphocyte (TCR) recognizes nonself antigens in the company of major histocompatibility complex (MHC) molecules presented to it by the antigen-presenting cell. The variable region of TCR is encoded by either a concatenation of variable region (TCR-V), diversity region (TCR-D), and joining region (TCR-J) genes, or a concatenation of TCR-V and TCR-J genes. The TCR-V genes exist as a multigene family in vertebrate species. Here we study the evolutionary relationships of TCR-V genes from humans, sheep, cattle, rabbits, mice, and chicken. These six species can be classified into two groups according to the frequency of γδ T-cells in their peripheral T-cell populations. The "γδ low" group of species includes humans and mice, in which γδ T-cells constitute very limited portion of the T-cell population. The "γδ high" group includes sheep, cattle, rabbits, and chicken, in which γδ T-cells comprise up to 60% of the T-cell population. Here, we compiled TCR-V sequences from the six species and conducted a phylogenetic analysis. We identified various TCR-V gene subgroups based on the analysis. We found that humans and mice have representatives from nearly all of the subgroups identified, while other species have lost subgroups to different extent. Therefore, the γδ low species have a high degree of diversity of TCR-V genes, while γδ high species all have limited diversity of TCR-V genes. This pattern is similar to that found for immunoglobulin variable region (IGV) genes.
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    Immunogenetics 50 (1999), S. 329-335 
    ISSN: 1432-1211
    Keywords: Key words Marsupials ; Light chains ; Variable regions ; IGK ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  A full-length and several partial cDNAs encoding IGK light chains from the marsupial South American opossum, Monodelphis domestica, were isolated and characterized. Using these clones as a starting point, the expressed IGKV repertoire was sampled by anchored polymerase chain reaction using an IGKC-specific primer. Based on nucleotide sequences of twenty unique, expressed IGKV-J combinations, there are at least four IGKV families and two J segments. Southern blot analysis revealed each IGK-V family contains multiple gene segments totaling at least thirty-five IGKV in the opossum genome. No evidence for particular, recurrent IGKV-J combinations in the opossum IGK repertoire was seen, rather the V-J combinations appeared random and diverse. Each of the four IGKV families appear more closely related to V segments from placental mammals than to each other, suggesting the duplication of the IGKV families prior to the separation of marsupials and placental mammals more than one-hundred-million years ago. Overall, the complexity of opossum light chain V segments appears greater than that found in the heavy chain, and light chains are likely to contribute significantly to Ig diversity in this species.With this report, the homologues encoding all three classes of eutherian Ig chains, IGH, IGL, and IGK, have been described in a non-placental mammal.
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  • 57
    ISSN: 1432-1211
    Keywords: Key words MHC ; MIC ; Nonhuman primates ; Evolution
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    Immunogenetics 49 (1999), S. 295-302 
    ISSN: 1432-1211
    Keywords: Key words Major histocompatibility complex ; Class II ; Antigen processing ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Proper peptide presentation by major histocompatibility complex (MHC)-encoded class II antigens is dependent on the products of the MHC DM loci. We identified the rabbit orthologues (RLA-DMA and -DMB) of human HLA-DMA and -DMB and found that they have 76.9% and 78.8% identity with HLA-DMA and -DMB, respectively. Like classical class II MHC genes, RLA-DM genes are more closely related to human HLA-DM genes than to mouse H2-DM. Among the DM family, there is a high degree of variability at the amino terminus of the DMa chains, and length variability in the cytoplasmic tails of both DMα and DMβ. The rabbit DM genes are coexpressed with class II genes in lymphoid tissues, as are the DM genes of other mammals. The RLA-DM locus maps to the class II region of the rabbit MHC, and is flanked by the DP and DOB loci. Despite having some similarities to class II genes of bony fishes, the DM family represents a separate branch of the MHC class II family.
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  • 59
    ISSN: 1432-1211
    Keywords: Key words Mhc ; Class II A ; Cichlid ; Fish ; Evolution
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  • 60
    ISSN: 1432-1211
    Keywords: Key words Beta2-microglobulin ; Evolution ; Sturgeon ; cDNA ; Genomic
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  • 61
    ISSN: 1432-0789
    Keywords: Key words Microbial biomass C ; Water-soluble organic carbon ; Light fraction organic carbon ; Fertilizer ; nitrogen ; 13C nuclear magnetic resonance ; Infrared spectrophotometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Soil samples taken from four experimental sites that had been cropped to continuous corn for 3–11 years in Ontario and Quebec were analyzed to evaluate changes in quantity and quality of labile soil organic carbon under different nitrogen (N) fertility and tillage treatments. Addition of fertilizer N above soil test recommendations tended to decrease amounts of water-soluble organic carbon (WSOC) and microbial biomass carbon (MBC). The quality of the WSOC was characterized by 13C nuclear magnetic resonance and infrared spectrophotometry and the results indicated that carbohydrates, long-chain aliphatics and proteins were the major components of all extracts. Similar types of C were present in all of the soils, but an influence of management was evident. The quantity of soil MBC was positively related to the quantities of WSOC, carbohydrate C, and organic C, and negatively related to quantities of long-chain aliphatic C in the soil. The quantity of WSOC was positively related to the quantities of protein C, carbohydrate C, and negatively related to the quantity of carboxylic C. The quantity of soil MBC was not only related to quantities of soil WSOC but also to the quality of soil WSOC.
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    Biology and fertility of soils 26 (1998), S. 169-172 
    ISSN: 1432-0789
    Keywords: Key words Urea ; Coated fertilizers ; Ammonium ; nitrogen ; Nitrate nitrogen ; Nitrogen uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Understanding the fate of different forms of nitrogen (N) fertilizers applied to soils is an important step in enhancing N use efficiency and minimizing N losses. The growth and N uptake of two citrus rootstocks, Swingle citrumelo (SC), and Cleopatra mandarin (CM), seedlings were evaluated in a pot experiment using a Candler fine sand (hyperthermic, uncoated, Typic Quartzipsamments) without N application or with 400 mg N kg–1 applied as urea or controlled-release fertilizers (CRF; either as Meister, Osmocote, or Poly-S). Meister and Osmocote are polyolefin resin-coated urea with longevity of N release for 270 days (at 25°C). Poly-S is a polymer and sulfur-coated urea with release duration considerably shorter than that of either Meister or Osmocote. The concentrations of 2 M KCl extractable nitrate nitrogen (NO3 –-N) and ammonium nitrogen (NH4 +-N) in the soil sampled 180 days and 300 days after planting were greater in the soil with SC than with CM rootstock seedlings. In most cases, the extractable NH4 + and NO3 – concentrations were greater for the Osmocote treatment compared to the other N sources. For the SC rootstock seedlings, dry weight was greater with Meister or Poly-S compared with either Osmocote or urea. At the end of the experiment, ranking of the various N sources, with respect to total N uptake by the seedlings, was: Meister = Osmocote 〉 Poly-S 〉 Urea 〉 no N for CM rootstock, and Meister = Poly-S = Osmocote 〉 Urea 〉 no N for SC rootstock. The study demonstrated that for a given rate of N application the total N uptake by seedlings was greater for the CRF compared to urea treatment. This suggests that various N losses were lower from the CRF source as compared to those from soluble fertilizers.
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  • 63
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    Biology and fertility of soils 26 (1997), S. 31-34 
    ISSN: 1432-0789
    Keywords: Key words Microbial biomass ; Air-drying ; Extractable ; nitrogen ; Extractable phosphorus ; Tropical soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The microbial contribution to extractable N and P after the air-drying of eight Indian dry tropical Ultisols was quantified. Air-drying of the soils decreased microbial biomass C by 25–53% but increased extractable N and P by 14–34% and 24–121%, respectively. This increase in the extractable N and P was accounted for, to some extent, by microbial biomass killed due to air-drying. Microbial biomass contributes 17–36% and 19–82% to the extractable N and P, respectively, possibly due to air-drying of the soils. I conclude that due to contamination of microbial biomass with the available nutrients in air-dried soils, measurements of extractable nutrients should be made on field-moist soils.
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  • 64
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    Bulletin of volcanology 59 (1997), S. 161-170 
    ISSN: 1432-0819
    Keywords: Key words Structure ; Evolution ; Uplift ; Geodetic modeling ; Alban Hills
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The Alban Hills, a Quaternary volcanic center lying west of the central Apennines, 15–25 km southeast of Rome, last erupted 19 ka and has produced approximately 290 km3 of eruptive deposits since the inception of volcanism at 580 ka. Earthquakes of moderate intensity have been generated there at least since the Roman age. Modern observations show that intermittent periods of swarm activity originate primarily beneath the youngest features, the phreatomagmatic craters on the west side of the volcano. Results from seismic tomography allow identification of a low-velocity region, perhaps still hot or partially molten, more than 6 km beneath the youngest craters and a high-velocity region, probably a solidified magma body, beneath the older central volcanic construct. Thirty centimeters of uplift measured by releveling supports the contention that high levels of seismicity during the 1980s and 1990s resulted from accumulation of magma beneath these craters. The volume of magma accumulation and the amount of maximum uplift was probably at least 40×106 m3 and 40 cm, respectively. Comparison of newer levelings with those completed in 1891 and 1927 suggests earlier episodes of uplift. The magma chamber beneath the western Alban Hills is probably responsible for much of the past 200 ka of eruptive activity, is still receiving intermittent batches of magma, and is, therefore, continuing to generate modest levels of volcanic unrest. Bending of overburden is the most likely cause of the persistent earthquakes, which generally have hypocenters above the 6-km-deep top of the magma reservoir. In this view, the most recent uplift and seismicity are probably characteristic and not precursors of more intense activity.
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  • 65
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    Journal of molecular evolution 5 (1975), S. 187-197 
    ISSN: 1432-1432
    Keywords: Evolution ; Cytochrome C ; Substitution ; Covarion ; Monte-Carlo Simulations
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    Topics: Biology
    Notes: Summary A statistical analysis aimed at obtaining some informations on a possible correlation between simultaneous amino acid substitutions is proposed. This method is applied to a set of cytochromes C, at the level of tandem and triple substitutions separated along the peptide chain by 1 to 15 peptide bonds. Monte-Carlo simulations are performed and the results are compared. We find a significant occurence of three adjacent amino acid substitutions in which the first replacement requires a two nucleotide substitution. A possible explanation of this fact is proposed on the basis of covarions.
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  • 66
    ISSN: 1432-1432
    Keywords: Evolution ; κ-Casein ; Cytochrome b ; Artiodactyla ; Ruminantia ; Caprinae ; Capricornis
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    Topics: Biology
    Notes: Abstract Nucleotide sequences for the κ-casein precursor proteins have been determined from the genomic DNAs or hair roots of the Ruminantia. The coding regions, exons 2, 3, and 4, were amplified separately via the three kinds of PCRs and then directly sequenced. The primers were designed from the sequence of bovine κ-casein gene; they were applicable for the amplification of the κ-casein genes from the 13 species in the Ruminantia except exon 2 of the lesser mouse deer. These results permitted an easy phylogenetic analysis based on the sequences of an autosomal gene. A phylogenetic tree was constructed from the mature K-casein sequences and compared with the tree of the cytochrome b genes which were sequenced from the same individuals. The Cervidae (sika deer, Cervus nippon) were separated from the branch of the Bovidae on the tree of κ-casein genes with a relatively high confidence level of the bootstrap analysis, but included in the branch of the Bovidae on the tree of cytochrome b genes. The κ-casein tree indicated a monophyly of the subfamily Caprinae, although the internal branches were uncertain in the Caprinae. The tree based on the nucleotide sequences of cytochrome b genes clearly showed the relationships of the closely related species in the genus Capricornis consisting of serow (C. smatorensis), Japanese serow (C. crispus), and Formosan serow (C. swinhoei). These results would be explained by the difference of resolving power between the κ-casein and the cytochrome b sequences.
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  • 67
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    Journal of molecular evolution 7 (1976), S. 133-149 
    ISSN: 1432-1432
    Keywords: 5S rRNA ; Nucleotide Sequence Homology ; Evolution ; Mutation Frequencies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The problem of choosing an alignment of two or more nucleotide sequences is particularly difficult for nucleic acids, such as 5S ribosomal RNA, which do not code for protein and for which secondary structure is unknown. Given a set of ‘costs’ for the various types of replacement mutations and for base insertion or deletion, we present a dynamic programming algorithm which finds the optimal (least costly) alignment for a set of N sequences simultaneously, where each sequence is associated with one of the N tips of a given evolutionary tree. Concurrently, protosequences are constructed corresponding to the ancestral nodes of the tree. A version of this algorithm, modified to be computationally feasible, is implemented to align the sequences of 5S RNA from nine organisms. Complete sets of alignments and proto-sequence reconstructions are done for a large number of different con-figurations of mutation costs. Examination of the family of curves of total replacements inferred versus the ratio of transitions/trans-versions inferred, each curve corresponding to a given number of in-sertions-deletions inferred, provides a method for estimating relative costs and relative frequencies for these different types of mutation.
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  • 68
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    Journal of molecular evolution 43 (1996), S. 399-404 
    ISSN: 1432-1432
    Keywords: Asarum ; Dioscorea ; Angiosperms ; Evolution ; Legumins ; Seed proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Analysis of legumin-encoding cDNAs fromDioscorea caucasica Lipsky (Dioscoreaceae) and fromAsarum europaeum L. (Aristolochiaceae) shows that there is an especially methionine-rich legumin subfamily present in the lower angiosperm clades including the Monocotyledoneae. It is characterized by a methionine content of 3–4 mol% which is roughly triple the methionine proportion of most other legumins. These “MetR” legumins, if present, still have to be detected in the higher angiosperms including the important seed crops. Evolutionary analysis suggests that the MetR legumins are the result of a gene duplication allowing the differentiation of legumin genes according to their sulfur content. The duplication event must have taken place before the split into mono- and dicotyledonous plants but probably after the separation of angiosperms and gymnosperms.
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  • 69
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    Journal of molecular evolution 43 (1996), S. 685-689 
    ISSN: 1432-1432
    Keywords: Retroposons ; Integration targets ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genomic DNA fragments generated by the reverse transcription of cellular RNA are called retroposons. Because they are flanked by short repeats, mammalian retroposons are believed to integrate at staggered chromosomal breaks. Recently, a significant sequence pattern associated with the integration of Alu and ID repeats was identified (Jurka 1996). It is represented by the 5′ TTAAAA consensus sequence around the 5′ ends of flanking repeats of Alu, ID, as well as, of B1 and B2 retroposed elements as shown in this paper. This consensus is a potential target for enzymatic nicking which probably occurs in the complementary strand between 3′ AA and the following 3′ TTTT bases. The first four bases of the flanking repeats corresponding to the 3′ TTTT consensus sequence show some sequence variations that may be affected by complementary base pairing between the A-rich RNA tails and the DNA target sequences prior to nicking and reverse transcription. We discuss potential evidence for such base pairing based on correlated variations in nucleotide composition of different tail and target regions.
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  • 70
    ISSN: 1432-1432
    Keywords: Alleles ; Evolution ; Gene conversion ; Introns ; Nematode
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Globin genes from theCaenorhabditis speciesbriggsae andremanei were identified and compared with a previously describedC. elegans globin gene. The encoded globins share between 86% and 93% amino acid identity, with most of the changes in or just before the putative B helix.C. remanei was found to have two globin alleles,Crg1-1 andCrgl-2. The coding sequence for each is interrupted by a single intron in the same position. The exons of the two genes are only 1 % divergent at the nucleotide level and encode identical polypeptides. In contrast, intron sequence divergence is 16% and numerous insertions and deletions have significantly altered the size and content of both introns. Genetic crosses show thatCrg1-1 andCrgl-2 segregate as alleles. Homozygous lines for each allele were constructed and northern analysis confirmed the expression of both alleles. These data reveal an unusual situation wherein two alleles encoding identical proteins have diverged much more rapidly in their introns than the silent sites of their coding sequences, suggesting multiple gene conversion events.
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  • 71
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    Journal of molecular evolution 5 (1975), S. 47-55 
    ISSN: 1432-1432
    Keywords: Gene Duplication ; Dipeptides ; Posterior Pituitary Peptide ; Evolution ; Protein Sequence
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    Topics: Biology
    Notes: Summary We have compiled the dipeptide frequencies in 100 known protein sequences. We suggest that dipeptides which occur with low frequencies can be used to locate proteins where partial gene duplication may have taken place. The 48 residue sequence of posterior pituitary peptide contains two Cys Trp pairs. The adjacent portions of the sequence are compatible with a partial gene duplication in the evolutionary history of posterior pituitary peptide.
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  • 72
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    Journal of molecular evolution 6 (1975), S. 309-320 
    ISSN: 1432-1432
    Keywords: Aminoacyl Transfer ; Amino Acid Adenylate ; Imidazole Catalysis ; Evolution ; Peptide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Imidazole catalysis of phenylalanyl transfer from phenylalanine adenylate anhydride to the hydroxyl groups of homopolyribonucleotides was investigated as a chemical model of the biochemical aminoacylation of tRNA. Imidazole catalyzed transfer of phenylalanine to poly (U) increases from pH 6.5 to 7.7 and decreases above pH 7.7. At pH 7.7 approximately 10% of the phenylalanyl residues are transferred to poly (U). At pH 7.1, transfer to poly (U) was five times as great as to poly (A) and transfer to a poly (A) poly (U) double helix was negligible. At pH 7.1 approximately 45 mole percent linkages to poly (U) were monomeric phenylalanine; the remainder of the linkages were peptides of phenylalanine. The number of linkages and their lability to base and neutral hydroxylamine indicates that phenylalanine and its peptides are attached as esters to the 2′ hydroxyl groups throughout poly (U) and the 2′ (3) hydroxyl groups at the terminus of poly (U). These results do model the contemporary process of aminoacyl transfer to tRNA and continue to suggest that a histidine residue is in the active site of aminoacyl-tRNA-synthetases.
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  • 73
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    Journal of molecular evolution 7 (1976), S. 111-131 
    ISSN: 1432-1432
    Keywords: Crustacea ; Evolution ; Repeated DNA ; Molecular Hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Analysis of data obtained from molecular hybridization of3H-labeled repetitious DNA has been utilized to reconstruct the broad outlines of phylogenetic relationships among decapod Crustacea. This molecular reconstruction agrees reasonably well with the paleontological record, and with other schemes obtained by comparative morphological and serological approaches. Preliminary evidence is in line with the hypothesis that continuous addition of new repeated sequence families to the genome over long periods of time may in part account for the correlation observed between percent repetitious DNA hybridized and divergence time. It is tentatively concluded that a core of DNA base sequence homology has been highly conserved throughout the evolution of theCrustacea. Demonstration of inter-species sequence homology has important implications to models which relegate a genetic regulatory function to repeated DNAs.
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  • 74
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    Journal of molecular evolution 7 (1976), S. 185-195 
    ISSN: 1432-1432
    Keywords: Evolution ; Randomicity ; Counter-Example
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    Topics: Biology
    Notes: Summary Specific counter-examples are derived theoretically to the hypothesis that a random amino acid composition signifies a random evolutionary process.
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  • 75
    ISSN: 1432-1432
    Keywords: Bacilli, 16S rRNA ; Phylogeny ; Thermophile ; Evolution ; Oligonucleotide Fingerprint
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two modifications in the Sanger two dimensional electrophoretic procedure for RNA analysis are reported. One increases resolution on the primary fingerprint to the point that digests of large RNAs, of the size 1500–3000 nucleotides yield well resolved fingerprint patterns. The other is a novel endonucleolytic procedure that proves useful in determining sequences of the large oligonucleotides produced by T1 ribonuclease. These modifications have been used in determining the catalogs of oligomers produced by T1 ribonuclease digestion of 16S rRNAs from three related organisms,Bacillus subtilis, B.pumilus andB.stearothermophilus. The possible effects of adaptation to a thermophilic niche on ribosomal RNA primary structure and the phylogenetic relatedness of the two mesophilic Bacilli are discussed.
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  • 76
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    Journal of molecular evolution 6 (1975), S. 149-163 
    ISSN: 1432-1432
    Keywords: Electrophoretic Detectability ; Neutral Mutation Theory ; Evolution ; Mutation Rates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Routine electrophoretic surveys for genetic variation in natural populations depend primarily upon detecting differences in the net charge carried by a protein. We have calculated the proportion of base substitutions which would yield an electrophoretically detectable mutant protein, and the relative mutation rates among different charge classes, under a variety of simplifying assumptions. These calculations indicate that: (i) only 25 per cent of all single base mutations would lead to a charge change on a protein molecule. (ii) five distinct classes of electrophoretic variants can be generated from a specified protein by single base substitutions. (iii) the relative mutation rates differ markedly among the different charge classes which can be generated by single base substitutions. The estimates of the proportion of electrophoretically detectable mutant proteins and relative mutation rates among charge classes were relatively robust to changes in assumptions concerned with the kind and site of base substitutions and the amino acid composition of the protein.
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  • 77
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    Journal of molecular evolution 8 (1976), S. 79-94 
    ISSN: 1432-1432
    Keywords: Histones ; Evolution ; Prokaryotes ; Lower Eukaryotes ; Higher Eukaryotes
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    Topics: Biology
    Notes: Summary The occurrence of basic chromosomal proteins in lower eukaryotes provides a useful approach to the study of histone evolution and function in higher eukaryotes. The histones of higher plants and animals are very similar and some are nearly identical, suggesting a high degree of evolutionary conservation within this group of proteins. However, a literature survey reveals that in the lower eukaryotes the histone situation is quite variable. The ciliates, and the true and cellular slime molds possess basic chromosomal proteins that are very similar to the histones of higher plants and animals. Various other lower eukaryotes possess basic chromosomal proteins that resemble at least some of the major histone fractions, and some microorganisms possess basic chromosomal proteins that bear little or no relationship to higher plant and animal histones. Since histones play a major role in the control of gene expression and the maintenance of chromosome structure in higher organisms, the evolution of these proteins represents a major change in the packaging of DNA and the mode of regulating gene expression in eukaryotes.
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  • 78
    ISSN: 1432-1432
    Keywords: Evolution ; Expression patterns ; α-Amylase ; Glucose repression ; Starch induction ; Intra- and interspecific variation ; Drosophila ; Gene expression ; Regulatory genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Intraspecific variation of α-amylase activity in D. melanogaster and D. immigrans, which is distantly related to D. melanogaster, and interspecific variation of α-amylase activity in 18 Drosophila species were examined. The amount of intraspecific variation of α-amylase activities measured in terms of coefficient of variation in D. melanogaster and D. immigrans was one-half and one-tenth or less, respectively, of the interspecific variation in 18 Drosophila species. We also surveyed the response patterns of α-amylase activity to dietary carbohydrates at the larval and adult stages. The levels of α-amylase activity depended on both repression by dietary glucose (glucose repression) and induction by dietary starch (starch induction). In general, our data suggest that glucose repression was conserved among species at both stages while starch induction was mainly observed in larvae, although the degree of the response depended on species. In D. lebanonensis lebanonensis and D. serrata, larvae expressed electrophoretically different α-amylase variants (isozymes) from those of adult flies. These results may suggest that the regulatory systems responsible both for the response to environment and developmental expression are different among species in Drosophila.
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  • 79
    ISSN: 1432-1432
    Keywords: Soybean ; Ferritin ; Plant-animal ; Monocotyledons ; Dicotyledons ; Plastid ; Gene organization ; Evolution ; Intron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ferritin, a protein widespread in nature, concentrates iron −1011−1012-fold above the solubility within a spherical shell of 24 subunits; it derives in plants and animals from a common ancestor (based on sequence) but displays a cytoplasmic location in animals compared to the plastid in contemporary plants. Ferritin gene regulation in plants and animals is altered by development, hormones, and excess iron; iron signals target DNA in plants but mRNA in animals. Evolution has thus conserved the two end points of ferritin gene expression, the physiological signals and the protein structure, while allowing some divergence of the genetic mechanisms. Comparison of ferritin gene organization in plants and animals, made possible by the cloning of a dicot (soy-bean) ferritin gene presented here and the recent cloning of two monocot (maize) ferritin genes, shows evolutionary divergence in ferritin gene organization between plants and animals but conservation among plants or among animals; divergence in the genetic mechanism for iron regulation is reflected by the absence in all three plant genes of the IRE, a highly conserved, noncoding sequence in vertebrate animal ferritin mRNA. In plant ferritin genes, the number of introns (n = 7) is higher than in animals (n = 3). Second, no intron positions are conserved when ferritin genes of plants and animals are compared, although all ferritin gene introns are in the coding region; within kingdoms, the intron positions in ferritin genes are conserved. Finally, secondary protein structure has no apparent relationship to intron/exon boundaries in plant ferritin genes, whereas in animal ferritin genes the correspondence is high. The structural differences in introns/exons among phylogenetically related ferritin coding sequences and the high conservation of the gene structure within plant or animal kingdoms suggest that kingdom-specific functional constraints may exist to maintain a particular intron/exon pattern within ferritin genes. In the case of plants, where ferritin gene intron placement is unrelated to triplet codons or protein structure, and where ferritin is targeted to the plastid, the selection pressure on gene organization may relate to RNA function and plastid/nuclear signaling.
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  • 80
    ISSN: 1432-1432
    Keywords: Evolution ; Multigene family ; Recombination ; Trypanosome ; Variant surface glycoprotein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The surface of the parasitic protozoanTrypanosoma brucei spp. is covered with a dense coat consisting of a single type of glycoprotein molecule, the variant surface glycoprotein (VSG). There may be as many as 1,000 genes for VSG within the genome ofT. brucei, and the switch of expression from one to another is the phenomenon of antigenic variation. As an approach to understanding the evolution of VSG genes we have determined the genomic DNA sequences of the eight genes encoding the variant surface glycoprotein 117 (VSG) family. From these data we have observed a number of features concerning the relationships between these genes: (1) there is a region of high variability confined to the N-terminus of the coding sequence, and comparison of the sequences with the available X-ray diffraction crystal structures suggests that two of the most variable stretches within the N-terminal domain are present on surface-exposed loops, indicating a role for epitope selection in evolution of these genes; (2) the 29 nucleotides surrounding the splice acceptor site are absolutely conserved in all eight 117 VSG genes; (3) numerous insertion/deletion mutations are located within or immediately downstream of the C-terminal protein-coding sequences: (4) within 500 by downstream of the insertion/deletion mutations are one or two copies of a repeat motif highly homologous to the recombinogenic 76-bp repeat sequences present upstream of many VSG basic copy genes and the expression-linked copy.
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  • 81
    ISSN: 1432-1432
    Keywords: Metalloproteinase ; Disintegrin ; Evolution ; Venom ; Phylogeny ; Gene duplication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The evolution of the Metalloproteinase Disintegrin Cysteine-rich (MDC) gene family and that of the mammalian Matrix-degrading Metalloproteinases (MMPs) are compared. The alignment of snake venom and mammalian MDC and MMP precursor sequences generated a phylogenetic tree that grouped these proteins mainly according to their function. Based on this observation, a common ancestry is suggested for mammalian and snake venom MDCs; it is also possible that gene duplication of the already-assembled domain structure, followed by divergence of the copies, may have significantly contributed to the evolution of the functionally diverse MDC proteins. The data also suggest that the structural resemblance of the zinc-binding motif of venom MDCs and MMPs may best be explained by common ancestry and conservation of the proteolytic motifs during the divergence of the proteins rather than through convergent evolution.
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  • 82
    ISSN: 1432-1432
    Keywords: Krebs cycle ; Evolution ; Metabolism ; Citric acid cycle ; Chemical design
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The evolutionary origin of the Krebs citric acid cycle has been for a long time a model case in the understanding of the origin and evolution of metabolic pathways: How can the emergence of such a complex pathway be explained? A number of speculative studies have been carried out that have reached the conclusion that the Krebs cycle evolved from pathways for amino acid biosynthesis, but many important questions remain open: Why and how did the full pathway emerge from there? Are other alternative routes for the same purpose possible? Are they better or worse? Have they had any opportunity to be developed in cellular metabolism evolution? We have analyzed the Krebs cycle as a problem of chemical design to oxidize acetate yielding reduction equivalents to the respiratory chain to make ATP. Our analysis demonstrates that although there are several different chemical solutions to this problem, the design of this metabolic pathway as it occurs in living cells is the best chemical solution: It has the least possible number of steps and it also has the greatest ATP yielding. Study of the evolutionary possibilities of each one-taking the available material to build new pathways-demonstrates that the emergence of the Krebs cycle has been a typical case of opportunism in molecular evolution. Our analysis proves, therefore, that the role of opportunism in evolution has converted a problem of several possible chemical solutions into asingle-solution problem, with the actual Krebs cycle demonstrated to be the best possible chemical design. Our results also allow us to derive the rules under which metabolic pathways emerged during the origin of life.
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    Journal of molecular evolution 8 (1976), S. 387-388 
    ISSN: 1432-1432
    Keywords: Nitrate Respiration ; Fermentation ; Energy Metabolism ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary E. Broda's recent argument against our concept that nitrate respiration antedated oxygen respiration is criticized.
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  • 84
    ISSN: 1432-1432
    Keywords: Evolution ; Repetitive DNA ; SI Nuclease ; Sequence Organization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The organization of repetitive and single copy DNA sequences in sea urchin DNA has been examined with the single strand specific nuclease Sl fromAspergillus. Conditions and levels of enzyme were established so that single strand DNA was effectively digested while reassociated divergent repetitive duplexes remained enzyme resistant. About 25% of sea urchin DNA reassociates with repetitive kinetics to form Sl resistant duplexes of two distinct size classes derived from long and short repetitive sequences in the sea urchin genome. Fragments 2,000 nucleotides long were reassociated to Cot 20 and subjected to controlled digestion with Sl nuclease. About half of the resistant duplexes (13% of the DNA) are short, with a mode size of about 300 nucleotide pairs. This class exhibits significant sequence divergence, and principally consists of repetitive sequences which were interspersed with single copy sequences. About one-third of the long duplexes (4% of the DNA) are reduced in size after extensive Sl nuclease digestion to about 300 nucleotide pairs. About two-thirds of the long resistant duplexes (8% of the DNA) remains long after extensive SI nuclease digestion. These long reassociated duplexes are precisely base paired. The short duplexes are imprecisely paired with a melting temperature about 9°C below that of precisely paired duplexes of the same length. The relationship between length of repetitive duplex and precision of repetition is confirmed by an independent method and has been observed in the DNA of a number of species over a wide phylogenetic area.
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    Journal of molecular evolution 9 (1977), S. 131-158 
    ISSN: 1432-1432
    Keywords: Parvalbumins ; Evolution ; Maximum parsimony ; Troponin-C ; Myosin alkali light chain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Phylogenetic trees requiring the lowest sum of nucleotide replacements and gene duplicative events were constructed from the amino acid sequence data on ten gnathostome parvalbumins (PAR) and two related myofibrillar proteins troponin-C (TNC) and myosin alkali-light-chain (ALC). The origin and differentiation of the structural domains within these proteins were also investigated by the maximum parsimony method and by an alignment statistic for identifying evolutionarily related protein sequences. The results suggest, in agreement with the Weeds-McLachlan model, that tandem duplications in a precursor gene caused a primordial one-domain polypeptide (consisting of two helices with a calcium binding region in between) to double and then quadruple in size. Duplications of the gene coding for this four domain (I–II–III–IV) protein in an early metazoan, pre-gnathostome lineage gave rise to the separate loci for TNC, ALC, and PAR. TNC, which alone retained the Ca-binding function in each of its four domains, evolved much more slowly than either the ALC or PAR lineages. In the PAR lineage the I–II–III–IV structure was degraded, presumably by a partial gene deletion, to the II–III–IV structure during descent to the gnathostome ancestor of parvalbumins. Also during this period the mid region in domain II lost its Ca-binding function and, as it did so, evolved at an accelerated rate over other regions, a pattern indicative of positive selection for a change in function. In turn, from the gnathostome ancestor to the present, the mid regions of domains III and IV, which each retained Ca-bindung function, evolved much more slowly than other regions, a pattern indicative of stabilizing selection for preservation of function. Between the gnathostome and teleost-tetrapod ancestor a gene duplication separated the parvalbumins into anα-lineage and aβ-lineage. During this early vertebrate period PAR genes evolved at the extremely fast rate of 89 nucleotide replacements per 100 codons per 108 years (i.e. 89 NR %), but from the teleost-tetrapod ancestor to the present, bothα- andβ-PAR lineages evolved at a much slower rate, about 8 NR %. The use ofβ-parvalbumins as phylogenetic markers was complicated by presumptive evidence that paralogous (i.e. duplication dependent) gene lineages occur within this group. As a final point, in the genealogy of TNC, ALC, and PAR lineages, a non-random pattern of nucleotide replacements was observed between the reconstructed ancestral and descendant mRNA sequences. The pattern was similar to that observed for other protein genealogies and seems to reflect a bias in the genetic code for guanine to adenine and adenine to guanine transitions (especially at the first nucleotide position of the RNA codons) to produce amino acid substitutions which are compatible with the preservation of protein three-dimensional structure.
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  • 86
    ISSN: 1432-1432
    Keywords: Histone H1° ; 3′ untranslated region ; Slippage ; Sequence simplicity ; Evolution
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract The H1° gene has a long 3′ untranslated region (3′UTR) of 1,125 nucleotides in the rat and 1,310 in humans. Analysis of the sequences shows that they have features of simple DNA that suggest involvement of replication slippage in their evolution. These features include the length imbalance between the rat and human sequences; the abundance of single-base repeats, two-base runs and other simple motifs clustered along the sequence; and the presence of single-base repeat length polymorphisms in the rat and mouse sequences. Pairwise comparisons show numerous short insertions/deletions, often flanked by direct repeats. In addition, a proportion of short insertions/deletions results from length differences in conserved single-base repeats. Quantification of the sequence simplicity shows that simple sequences have been more actively incorporated in the human lineage than in the rodent lineage. The combination of insertions/deletions and nucleotide substitutions along the sequence gives rise to three main regions of homology: a highly variable central region flanked by more conserved regions nearest the coding region and the polyA addition site.
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  • 87
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    Journal of molecular evolution 6 (1975), S. 61-76 
    ISSN: 1432-1432
    Keywords: 5S ribosomal RNA ; Translation ; Evolution ; Molecular Architecture ; Conformational Changes
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    Topics: Biology
    Notes: Summary An extensive comparative analysis of the available primary sequence data on 5S rRNA has been made. A universal secondary structure is presented for procaryotic 5S rRNA which contains four helical regions. Eucaryotic 5S rRNAs are found to have only three of these helices and thus have a somewhat different architecture. In addition, a highly conserved segment of more than thirty nucleotides is identified in the 5′ half of the procaryotic molecule. This segment includes the oligonucleotide-CGAAC- which presumably binds to the t-RNA “common” sequence-GTΨCG-. Among the eucaryotes, the plants display a procaryotic nature in this region, but no eucaryote has the sequence -CGAAC- in this segment. A functional role for the procaryotic 5S rRNA molecule is discussed in which it is envisioned to undergo conformational change, i.e., coiling and uncoiling of one of the helices, which can result in a cyclic interaction of the 5S rRNA molecule with two t-RNA molecules. A general principle also emerges: the natural rotational motion inherent in coiling and uncoiling of nucleic acid helices can be converted quite simply to linear mechanical motion.
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  • 88
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    Journal of molecular evolution 5 (1975), S. 279-290 
    ISSN: 1432-1432
    Keywords: E.coli ; Mutagenesis ; Evolution ; Gene Transposition
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    Topics: Biology
    Notes: Summary The lactose fermenting genes inE.coli have been transposed to various chromosomal locations. The bacterial strains were mutagenized with different chemical mutagens and the frequency of Lac negative mutant colonies was measured as a function of lactose gene location in the chromosome. There appears to be a highly mutable location between 58–60 minutes on theE.coli map. This region does not appear to be correlated with the origin of DNA replication or with the terminus. The possible significance of this mutable region in the evolution of new bacterial genes is discussed.
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  • 89
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    Journal of molecular evolution 8 (1976), S. 143-153 
    ISSN: 1432-1432
    Keywords: 5S rRNA ; Comparative Analysis ; Secondary Structure ; Evolution ; Tuned Helix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The available comparative data on procaryotic 5S rRNA was extended through sequencing studies of eight gram positive procaryotes. Complete nucleotide sequences were presented for 5S rRNA fromBacillus subtilis, B. firmus, B.pasteurii, B.brevis, Lactobacillus brevis andStreptococcus faecalis. In addition, 5S rRNA oligonucleotide catalogs and partial sequence data were provided forB.cereus andSporosarcina ureae. These sequences and catalogs were discussed in terms of known features of procaryotic 5S rRNA architecture.
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  • 90
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    Journal of molecular evolution 9 (1976), S. 25-35 
    ISSN: 1432-1432
    Keywords: Genome organization ; Evolution ; Mitochondria
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary The mitochondrial genome of yeast (S. cerevisiae orS. carlsbergensis) appears to be formed by 60–70 genetic units, each one of which is formed by (1) a GC-rich sequence, possibly having a regulatory role; (2) a gene, and (3) an AT-rich spacer, which probably is not transcribed. Recombination in this genome appears to underlie a number of important phenomena. The organization of the mitochondrial genome of yeast and these recombinational events are discussed in relationship with the organization and evolution of the nuclear genome of eukaryotes.
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  • 91
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    Journal of molecular evolution 9 (1977), S. 343-347 
    ISSN: 1432-1432
    Keywords: Evolution ; Haemoglobin ; Cooperativity ; Lamprey ; Maximum parsimony
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary The sequences ofPetromyzon andAplysia globins are compared with the postulated vertebrate and mollusc-vertebrate ancestors to see if differences exist in the rates of evolution of different types of residue positions. Between the mollusc-vertebrate ancestor andAplysia globin there is no very striking pattern of changes except that the interior positions are relatively conserved. In the evolution ofPetromyzon haemoglobin, theα 1 β 2 contact area is relatively conserved. The homopolymeric binding of lamprey Hb seems to be a primitive function.
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  • 92
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    Journal of molecular evolution 9 (1977), S. 369-371 
    ISSN: 1432-1432
    Keywords: Methanogenic bacteria ; Primitive atmosphere ; Evolution ; Ecology ; Methane-carbon dioxide cycle
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    Topics: Biology
    Notes: Summary The phenotype and antiquity of methanogenic bacteria suggest them to have been one of the major factors determining a dynamic balance between CO2 and CH4 in the primitive atmosphere.
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  • 93
    ISSN: 1432-1432
    Keywords: Ribosome ; 5S RNA ; Conformation ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Fox and Woese (1975a) have shown that a model of 5S RNA secondary structure similar to the one originally derived forChlorella 5S RNA can be generalized with relatively minor variations to all sequenced 5S RNA molecules, i.e. that corresponding base paired regions can be formed at approximately the same positions. We present experimental data in favour of this hypothesis and show that the points at which ribonucleases T1, T2 and pancreatic ribonuclease cleave six different 5S RNA molecules under ‘mild’ conditions (high ionic strength, low temperature, low RNAase concentration) nearly always fall in the proposed single-stranded regions. We conclude that this model is a good approximation to the conformation of 5S RNA in solution.
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  • 94
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    Journal of molecular evolution 10 (1977), S. 123-135 
    ISSN: 1432-1432
    Keywords: Ancestral sequence ; Eye lens protein ; Evolution ; Phylogenetic tree
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The sequences of the A chains of the eye lens proteinα-crystallin from seventeen mammalian species were compared. They showed a generally slow rate of evolution, but with marked variations in different lineages. Most substitutions have occurred in the C-terminal part of the chain, which probably forms part of the surface of theα-crystallin aggregate. The ancestral sequence method of Dayhoff revealed interesting indications about the phylogenetic relationships between the eleven mammalian orders that were represented by the investigated species. Most evident was the divergence of marsupial and placental orders. A notable resemblance between the hyrax and elephant sequences was observed, setting them apart from the ungulates, including whale. Primates, rodents, lagomorphs, insectivores and tupaiids seem to derive from a common stem group. These phylogenetic inferences are discussed in relation to current palaeontological and taxonomical opinions, and compared to evidence from other protein sequence data.
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  • 95
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    Journal of molecular evolution 11 (1978), S. 109-120 
    ISSN: 1432-1432
    Keywords: Origin of Life ; Genetic code ; Protein synthesis ; Evolution ; Prebiotic reactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The fact that proteins contain onlya-amino acids and that protein structure is determined by 3′ → 5′ linked ribonucleotides is postulated to be the result of the copolymerization of these molecules in the prebiotic environment. Ribonucleotides therefore represent partial degradation products and proteins represent a side reaction developing from copolymerization. The basic structural unit of copolymerization is a nucleotide substituted with an amino acid at the 2′ position. Characteristics of modern amino and ribonucleic acid structure are all consistent with and necessary for this hypothesis. The characteristics and individual base assignments of the code also provide strong support for origin from the postulated copolymers. All characteristics of the code can be accounted for by this single hypothesis.
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  • 96
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    Journal of molecular evolution 11 (1978), S. 225-231 
    ISSN: 1432-1432
    Keywords: Phylogenetic denseness ; Phylogenetic trees ; Topology ; Molecular reconstructions ; Evolution ; Paleogenetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The concept of phylogenetic denseness bears critically on the accuracy of evolutionary pathways inferred from experimentally sequenced proteins isolated from extant species. In this paper I develop an objective measure,ρ, of denseness to supplement previous intuitive concepts and which permits one to use this concept in comparing the quality of different evolutionary reconstructions. This measure is used to examine several published phylogenetic trees: insulin, a-hemoglobin,β-hemoglobin, myoglobin, cytochromec, and the parvalbumin family. The paper emphasizes 1) the importance of denseness in accurately estimating the number of nucleotide replacements which separate homologous sequences when this estimation is made by the method of parsimony, 2) the value of this concept in assessing the quality of those estimates, and 3) the use of this concept as a biologically practical heuristic method for identifying poorly studied regions in a phylogenetic tree, whether or not the tree was obtained by the parsimony method.
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  • 97
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    Journal of molecular evolution 13 (1979), S. 95-101 
    ISSN: 1432-1432
    Keywords: Oparin Ocean ; Origin of Life ; Evolution ; Runaway greenhouse ; Photosynthesis ; Methanogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The widely accepted Oparin thesis for the origin and early evolution of life seems sufficiently far from the true state of affairs as to be considered incorrect. It is proposed that life on earth actually arose in the planet's atmosphere, however an atmosphere very different from the present one. Because of an extremely warm surface, the early earth may have possessed no liquid surface water, its water being partitioned between a molten crust and a fairly dense atmosphere. Early preliving systems are taken to arise in the droplet phase in such an atmosphere. The early earth, which resembled Venus then and to some extent now, underwent a transition to its present condition largely as a result of the evolution of methanogenic metabolism.
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  • 98
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    Journal of molecular evolution 16 (1980), S. 149-150 
    ISSN: 1432-1432
    Keywords: Exons ; Evolution ; Heme-binding proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary It is known that globin genes contain three exons with the middle exon coding for a four-helical supersecondary structure responsible for heme binding. Since this portion of the globin peptide chain can be structurally superimposed onto the cytochromec and cytochromeb 5 chains (Argos and Rossmann 1979), it can be inferred that the cytochromec gene will contain only one coding sequence while the cytochromeb 5 gene will be composed of three exons as found in the globin gene.
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  • 99
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    Journal of molecular evolution 16 (1980), S. 211-267 
    ISSN: 1432-1432
    Keywords: Nucleic acids ; Proteins ; Natural selection ; Genetics ; Nonrandom molecular divergence ; Nonrandom REH theory ; Evolution ; mRNA ; DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary REH theory is extended by deriving the theoretical equations that permit one to analyze the nonrandom molecular divergence of homologous genes and proteins. The nonrandomicities considered are amino acid and base composition, the frequencies with which each of the four nucleotides is replaced by one of the other three, unequal usage of degenerate codons, distribution of fixed base replacements at the three nucleotide positions within codons, and distributions of fixed base replacements among codons. The latter two distributions turn out to dominate the accuracy of genetic distance estimates. The negative binomial density is used to allow for the unequal mutability of different codon sites, and the implications of its two limiting forms, the Poisson and geometric distributions, are considered. It is shown that the fixation intensity — the average number of base replacements per variable codon - is expressible as the simple product of two factors, the first describing the asymmetry of the distribution of base replacements over the gene and the second defining the ratio of the average probability that a codon will fix a mutation to the probability that it will not. Tables are given relating these features to experimentally observable quantities inα hemoglobin,β hemoglobin, myoglobin, cytochromec, and the parvalbumin group of proteins and to the structure of their corre-sponding genes or mRNAs. The principal results are (1) more accurate methods of estimating parameters of evolutionary interest from experimental gene and protein sequence data, and (2) the fact that change in gene and protein structure has been a much less efficient process than previously believed in the sense of requiring many more base replacements to effect a given structural change than earlier estimation procedures had indicated. This inefficiency is directly traceable to Darwinian selection for the nonrandom gene or protein structures necessary for biological function. The application of these methods is illustrated by detailed consideration of the rabbitα -andβ hemoglobin mRNAs and the proteins for which they code. It is found that these two genes are separated by about 425 fixed base replacements, which is a factor of two greater than earlier estimates. The replacements are distributed over approximately 114 codon sites that were free to accept base mutations during the divergence of these two genes.
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  • 100
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    Journal of molecular evolution 17 (1981), S. 31-42 
    ISSN: 1432-1432
    Keywords: Pea ; Mung bean ; Genome organization ; Evolution ; Amplification ; Repetitive DNA ; Single copy DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Essentially all of the sequences in the pea (Pisum sativum) genome which reassociate with single copy kinetics at standard (Tm -25°C) criterion follow repetitive kinetics at lower temperatures (about Tm-35°C). Analysis of thermal stability profiles for presumptive single copy duplexes show that they contain substantial mismatch even when formed at standard criterion. Thus most of the sequences in the pea genome which are conventionally defined as “single copy” are actually “fossil repeats” — that is, they are members of extensively diverged (mutuated) and thus presumably ancient families of repeated sequences. Coding sequences as represented by a cDNA probe prepared from poly-somal poly(A) + mRNA reassociate with single copy kinetics regardless of criterion and do not form mismatched duplexes. The coding regions thus appear to be composed of true single copy sequences but they cannot represent more than a few percent of the pea genome. Ancient diverged repeats are present, but not a prominent feature of the smaller mung bean (Vigna radiata) genome. An extension of a simple evolutionary model is proposed in which these and other differences in genome organization are considered to reflect different rates of sequence amplification or genome turnover during evolution. The model accounts for some of the differences between typical plant and animal genomes.
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