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1.
ECKHARD WERRIES ALFRED FRANZ SIBYLLE GEISEMEYER 《The Journal of eukaryotic microbiology》1990,37(6):576-580
ABSTRACT. Homogenates of trophozoites of Entamoeba histolytica were shown to bring about the total degradation of glycogen while purified phosphorylase of the same source alone yielded a limit dextrin as end product. An enzyme system capable of debranching the limit dextrin was obtained from the 40,000 g pellet by extraction in aqueous medium, purified by gel filtration on Fractogel TSK HW-55(F), and separated from phosphorylase by chromatography on Blue Sepharose CL-6B and aminobutyl Agarose. The glycogen-debranching system was purified 540-fold to a state of homogeneity by criterion of disc-gel electrophoresis. The purified enzyme was able to degrade glycogen-limit dextrin in the presence of phosphorylase and exhibited activities of both amylo-1,6-glucosidase (EC 3.2.1.33) and 4- α -glucanotransferase (EC 2.4.1.25). Although amylo-1,6-glucosidase released glucose from a glycogen-phosphorylase limit dextrin, transferase activity moved single glucose residues from the limit dextrin to 4-nitrophenyl- α -glucoside yielding successively 4-nitrophenyl- α -maltoside and 4-nitrophenyl- α -maltotrioside that could be detected by HPLC. Native glycogen-debranching system exhibited a relative molecular mass of Mr = 180,000 ± 10% by gel filtration and gel electrophoresis in both denaturing and nondenaturating conditions. 相似文献
2.
NICO M. FRANZ 《Zoological Journal of the Linnean Society》2012,166(3):559-623
The weevil genus Azotoctla gen. nov. (Coleoptera: Curculionidae: Curculioninae: Acalyptini Thomson), is described to accommodate the following 15 new Neotropical species: Azotoctla aecuatorialis sp. nov. (Ecuador), Azotoctla anerunca sp. nov. (Ecuador), Azotoctla angustacra sp. nov. (Ecuador), Azotoctla curvirostra sp. nov. (Peru), Azotoctla dasygastra sp. nov. (Costa Rica and Honduras), Azotoctla femorata sp. nov. (Colombia, Costa Rica, Ecuador and Panama), Azotoctla gomezi sp. nov. (Colombia, Costa Rica and Panama), Azotoctla gottsbergeri sp. nov. (Brazil), Azotoctla clemmyssa sp. nov. (Colombia), Azotoctla melolauta sp. nov. (Colombia), Azotoctla migueli sp. nov. (Colombia), Azotoctla nana sp. nov. (Panama), Azotoctla punctata sp. nov. (Costa Rica), Azotoctla tibiatra sp. nov. (Belize), and Azotoctla tuberquiai sp. nov. (Colombia). Azotoctla is placed in the tribe Acalyptini, subtribe Staminodeina Franz, thus representing the sister taxon of Staminodeus Franz. The monophyly of Azotoctla is supported by the following inferred traits: a noncarinate rostrum that is tumescent above the antennal insertion in males; equilaterally subtriangular hemisternites of the male sternum 8; paired, longitudinal, laterally positioned sclerites of the aedeagus; and a bifurcate lamina of the female sternum 8, which bears explanate, diverging furcal arms. A key to the species of Azotoctla is provided; and the salient features of each species are illustrated and presented along with distributional and natural history data. A morphological cladistic analysis of 23 terminal species (eight outgroup, 15 ingroup) and 33 characters yielded a single most parsimonious cladogram (length = 75 steps, consistency index = 52, retention index = 77), with the ingroup topology ((A. aecuatorialis, (A. anerunca, A. gottsbergeri)), (A. punctata, ((A. angustacra, A. nana), (A. tibiatra, (A. clemmyssa, (A. curvirostra, A. femorata)), (A. melolauta, ((A. gomezi, A. migueli), (A. dasygastra, A. tuberquiai))))))). Species of Azotoctla are reproductively associated with the ephemeral staminodes of different members of the Neotropical monocot family Cyclanthaceae; most commonly with the widespread genus Carludovica Ruiz & Pavón. The interspecific homogeneity in external morphology, coupled with marked differences in genital traits and an apparent absence of narrow geographical ranges mediated by either host plants and/or biogeographical factors, jointly suggest that the diversification of Azotoctla is a relatively recent phenomenon and driven strongly by sexual selection. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 559–623. 相似文献
3.
Summary At metamorphosis the attachment of the Plumatella larva to the substrate is effected by secretions from glandular cells in the apical plate, the leading pole during swimming. The larval mantle folds back and slides down towards the substrate. By ciliary activity an adhesive secretion is spread over the metamorphosing larva and the attachment area. Two polypides appear through the larval terminal opening. The mantle fold, together with gland cells, nerve cells, sensory cells, and muscle cells from the larva form a nutritive cell mass. Reduction of this nutritive cell mass is accomplished by autolysis and phagocytosis. An invaginated area of the nutritive cell mass is provided with a dense layer of microvilli, which seem to have an absorbtive function. The nutritive cell mass consisting of transitory larval tissues provides a significant source of nutrient for the developing polypide buds. 相似文献
4.
We investigated the interaction of rhizospheric nitric oxide (NO) concentration (i.e. low, ambient or high) and soil nitrogen (N) availability (i.e. low or high) with organic and inorganic N uptake by fine roots of Pinus sylvestris L. seedlings by 15N feeding experiments under controlled conditions. N metabolites in fine roots were analysed to link N uptake to N nutrition. NO affected N uptake depending on N source and soil N availability. The suppression of nitrate uptake in the presence of ammonium and glutamine was overruled by high NO. The effects of NO on N uptake with increasing N availability showed different patterns: (1) increasing N uptake regardless of NO concentration (i.e. ammonium); (2) increasing N uptake only with high NO concentration (i.e. nitrate and arginine); and (3) decreasing N uptake (i.e. glutamine). At low N availability and high NO nitrate accumulated in the roots indicating insufficient substrates for nitrate reduction or its storage in root vacuoles. Individual amino acid concentrations were negatively affected with increasing NO (i.e. asparagine and glutamine with low N availability, serine and proline with high N availability). In conclusion, this study provides first evidence that NO affects N uptake and metabolism in a conifer. 相似文献
5.
GUILLAUME TCHERKEZ RUDI SCHÄUFELE SALVADOR NOGUÉS CLÉMENT PIEL ARNOUD BOOM GARY LANIGAN CÉCILE BARBAROUX CATARINA MATA SLIMAN ELHANI DEBBIE HEMMING CHRISTINA MAGUAS DAN YAKIR FRANZ W. BADECK HOWARD GRIFFITHS HANS SCHNYDER JALEH GHASHGHAIE 《Plant, cell & environment》2010,33(6):900-913
While there is currently intense effort to examine the 13C signal of CO2 evolved in the dark, less is known on the isotope composition of day‐respired CO2. This lack of knowledge stems from technical difficulties to measure the pure respiratory isotopic signal: day respiration is mixed up with photorespiration, and there is no obvious way to separate photosynthetic fractionation (pure ci/ca effect) from respiratory effect (production of CO2 with a different δ13C value from that of net‐fixed CO2) at the ecosystem level. Here, we took advantage of new simple equations, and applied them to sunflower canopies grown under low and high [CO2]. We show that whole mesocosm‐respired CO2 is slightly 13C depleted in the light at the mesocosm level (by 0.2–0.8‰), while it is slightly 13C enriched in darkness (by 1.5–3.2‰). The turnover of the respiratory carbon pool after labelling appears similar in the light and in the dark, and accordingly, a hierarchical clustering analysis shows a close correlation between the 13C abundance in day‐ and night‐evolved CO2. We conclude that the carbon source for respiration is similar in the dark and in the light, but the metabolic pathways associated with CO2 production may change, thereby explaining the different 12C/13C respiratory fractionations in the light and in the dark. 相似文献
6.
STEVE SMITH THOMAS MANG JOELLE GOÜY DE BELLOCQ HELMUT SCHASCHL CLAUDIA ZEITLHOFER KLAUS HACKLNDER FRANZ SUCHENTRUNK 《Molecular ecology》2010,19(19):4131-4143
The link between adaptive genetic variation, individual fitness and wildlife population dynamics is fundamental to the study of ecology and evolutionary biology. In this study, a Bayesian modelling approach was employed to examine whether individual variability at two major histocompatibility complex (MHC) class II loci (DQA and DRB) and eight neutral microsatellite loci explained variation in female reproductive success for wild populations of European brown hare (Lepus europaeus). We examined two aspects of reproduction: the ability to reproduce (sterility) and the number of offspring produced (fecundity). Samples were collected from eastern Austria, experiencing a sub‐continental climatic regime, and from Belgium with a more Atlantic‐influenced climate. As expected, reproductive success (both sterility and fecundity) was significantly influenced by age regardless of sampling locality. For Belgium, there was also a significant effect of DQA heterozygosity in determining whether females were able to reproduce (95% highest posterior density interval of the regression parameter [−3.64, −0.52]), but no corresponding effect was found for Austria. In neither region was reproduction significantly associated with heterozygosity at the DRB locus. DQA heterozygotes from both regions also showed a clear tendency, but not significantly so, to produce a larger number of offspring. Predictive simulations showed that, in Belgium, sub‐populations of homozygotes will have higher rates of sterile individuals and lower average offspring numbers than heterozygotes. No similar effect is predicted for Austria. The mechanism for the spatial MHC effect is likely to be connected to mate choice for increased heterozygosity or to the linkage of certain MHC alleles with lethal recessives at other loci. 相似文献
7.
Culture is widely thought to be beneficial when social learning is less costly than individual learning and thus may explain the enormous ecological success of humans. Rogers (1988. Does biology constrain culture. Am. Anthropol. 90 : 819–831) contradicted this common view by showing that the evolution of social learning does not necessarily increase the net benefits of learned behaviours in a variable environment. Using simulation experiments, we re‐analysed extensions of Rogers’ model after relaxing the assumption that genetic evolution is much slower than cultural evolution. Our results show that this assumption is crucial for Rogers’ finding. For many parameter settings, genetic and cultural evolution occur on the same time scale, and feedback effects between genetic and cultural dynamics increase the net benefits. Thus, by avoiding the costs of individual learning, social learning can increase ecological success. Furthermore, we found that rapid evolution can limit the evolution of complex social learning strategies, which have been proposed to be widespread in animals. 相似文献
8.
J. M. FRANZ 《The Annals of applied biology》1964,53(3):510-515
Animal dispersion was defined by Wynne-Edwards (1962) as 'the placement of individuals and groups of individuals within the habitats they occupy, and the processes by which this is brought about'. This paper deals with a limited aspect of this theme, namely with the influence of the dispersion of host or enemy individuals on their mutual interaction. Obviously, there can only be a relation between feeding organisms and food, between killer and victim, if they coincide in space and in time. Thus, what first seemed to be a limited topic evolves as one of the basic chapters of relations among organisms, that of coincidence (cf. Thalenhorst, 1951). It seems to be impossible to deal with space coincidence here without mentioning time coincidence, too. Recognizing the tremendous amount of information available on this subject, I should like to give some examples only, first on enemy action without man's interference and secondly on human action which either favours or disrupts space coincidence of both groups of organisms. For the sake of brevity, the term host will be frequently used for host and prey together and examples will mostly refer to insects. 相似文献
9.
CHANGES IN THE BODILY FORM OF DESCENDANTS OF IMMIGRANTS 总被引:1,自引:0,他引:1
FRANZ BOAS 《American anthropologist》1912,14(3):530-562
10.
NICO M. FRANZ 《Biological journal of the Linnean Society. Linnean Society of London》2004,81(4):483-517
The evolutionary history of the interaction among species of derelomine flower weevils (Coleoptera: Curculionidae: Derelomini) and the Panama-hat palm Carludovica (Cyclanthaceae) is analysed with emphasis on the congruence of (1) topologies and (2) character state transformations in each of the Neotropical clades. For this purpose cladistic analyses are complemented with host plant records, natural history information and selected morphological studies of the associated taxa. The interaction is specialized, involving pollination, oviposition into the inflorescences and the predation of seeds (particularly within Systenotelus ). As results from a range of standard coevolutionary methods of analysis indicate, however, events of colonization, extinction and independent (non-reciprocal) speciation have been abundant throughout the history of the association. At the same time it is possible to specify the homology and succession of characters among species of derelomines and Carludovica and interpret them as reciprocal adaptations to attack and protect the seeds, respectively. It is argued that – in light of the limited evolutionary stability of many insect–plant interactions – the question of coevolution is most effectively addressed by combining information from the character- and topology-based approaches. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 81 , 483–517. 相似文献