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The majority of terrestrial biomass is wood, but the elemental composition of its potential consumers, xylophages, differs hugely from that of wood. This causes a severe nutritional imbalance. We studied the stoichiometric relationships of 11 elements (C, N, P, K, Ca, Mg, Fe, Zn, Mn, Cu, Na) in three species of pine-xylem-feeding insects, Stictoleptura rubra, Arhopalus rusticus (Coleoptera, Cerambycidae) and Chalcophora mariana (Coleoptera, Buprestidae), to elucidate their mechanisms of tissue growth and to match their life histories to their dietary constraints. These beetles do not differ from other Coleoptera in their absolute elemental compositions, which are approximately 1000 (N), 100 (P, Cu) and 50 (K, Na) times higher than in dead but undecayed pine wood. This discrepancy diminishes along the wood decay gradient, but the elemental concentrations remain higher by an order of magnitude in beetles than in highly decayed wood. Numerical simulation of the life history of S. rubra shows that feeding on nutrient-poor undecayed wood would extend its development time to implausible values, whereas feeding on highly decomposed wood (heavily infected with fungi) would barely balance its nutritional budget during the long development period of this species. The changes in stoichiometry indicate that the relative change in the nutrient levels in decaying wood cannot be attributed solely to carbon loss resulting from decomposer respiration: the action of fungi substantially enriches the decaying wood with nutritional elements imported from the outside of the system, making it a suitable food for wood-eating invertebrates. 相似文献
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L(-)-, and D(+)-enantiomers of 1-amino-2-phenylethylphosphonic acid (PheP), a phosphonic analogue of phenylalanine, inhibit the activity of L-phenylalanine ammonia-lyase (EC 4.3.1.5) of potato tuber tissue in vitro. The apparent type of inhibition depends on concentration of PheP; as the concentration of D-PheP is raised from 10(-5) M to 2.5 X 10(-3) M, the type of inhibition shifts from competitive through mixed and non-competitive to uncompetitive. L-PheP exerts either a competitive or mixed-type inhibition at low (10(-6)-10(-5) M) or moderate (5 X 10(-5)-2 X 10(-4) M) concentration. Ki for the concentration range of competitive inhibition were 6.5 X 10(-6) M, 5.3 X 10(-5)M and 1.6 X 10(-5) M for L-, D-, and D,L-PheP, respectively. These Ki values are valid for a relatively narrow range of L-Phe concentration (0.2-4 mM) as L-phenylalanine ammonia-lyase does not follow the Michaelis-Menten kinetics of the reaction. 相似文献
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G. Ruhenstroth-Bauer H. Baumer J. Kugler R. Spatz W. Sönning B. Filipiak 《International journal of biometeorology》1984,28(4):333-340
The possibility of connections between weather and the onset of epileptic seizures has long been suggested (see, for example, the Hammurabi Codex 1600 BC). Work in the 20th Century points to a probability that the onset of both local and generalised epilepsy is significantly influenced by an interaction between genetic and extrinsic factors. In an attempt to clarify the situation a detailed study of the history of 315 attacks from 1 Jan. to 31 July 1981 suffered by a small number of patients in Munich has been undertaken. Although linkages between classical meteorological parameters and the onset of seizures are very weak, links with more generalised indexes (e.g. passage of fronts and disturbances) are more promising. However, the correlation between onsets and atmospherics of 28 KHz (positive) and 10 KHz (negative) impulses, are significant and call for urgent study. 相似文献
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Marchlewska K Kula K Walczak-Jedrzejowska R Oszukowska E Filipiak E Slowikowska-Hilczer J 《Journal of experimental zoology. Part A, Ecological genetics and physiology》2011,315(6):329-336
Follicle-stimulating hormone (FSH) and triiodothyronine (T3) are known regulatory factors of spermatogenesis initiation. Connexin 43 (Cx43) is the most ubiquitous constitutive protein of gap junctions in the testis. This study evaluates the effects of the hyperstimulation of FSH and T3 during testicular maturation on Cx43 expression in the testis. The newborn, male Wistar rats were divided randomly into four experimental groups: FSH group-daily injections of FSH 7.5?IU/animal; T3 group-100?μg T3/kg body weight; FSH+T3 group-both substances; A control group-received vehicles in the same volume. Proliferating cell nuclear antigen immunohistochemistry and toluidine blue staining were used to determine the germ cell proliferation and degeneration. Cx43 immunolocalization was evaluated to find Cx43 maturational changes. Under FSH treatment, the proliferation rate was high so the total number of Sertoli cells increased with a low level of degeneration and lumen formation. T3 stimulation evoked a reduction in the proliferation rate and a decrease in Sertoli cell number but with intensive formation of lumen. T3+FSH inhibited the proliferation rate and stimulated lumen formation together with degeneration, which negatively influenced the number of germ cells in the seminiferous epithelium. We conclude that T3 action seems to be particularly connected with the maturation of Cx43 gap junctions. FSH stimulates maturation of Sertoli cell function, but this effect may take place regardless of the presence of Cx43-dependent intercellular communication. The hyperstimulation of both FSH and T3 damages Cx43 connections and hence evokes regressional changes in the seminiferous epithelium. 相似文献
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Programmed cell death (PCD) and phagocytotic activity of immune cells play a pivotal role in insect development. We examined the influence of Zn2+, an important element to fundamental biological processes, on phagocytosis and apoptosis of hemocytes in two fly species: Musca domestica and Drosophila melanogaster. Hemocytes were isolated from the third instar larvae of both species and treated for 3 h with zinc chloride solutions, containing 0.35 mM or 1.7 mM of Zn2+, and untreated as control. Phagocytotic activity of hemocytes was examined by flow cytometry after adding latex fluorescent beads to the medium, while apoptosis was evaluated by application of annexinV-FITC and pan-caspase-FITC inhibitor. Mitochondrial viability was determined by measuring resazurin absorbancy in the cell medium. The obtained results showed that Zn2+ increases phagocytosis and affects PCD of both species hemocytes but each in a different way. Zinc decreases fraction of annexin-positive hemocytes in M. domestica but increases it in D. melanogaster. The pan-caspase analysis revealed low and high activity of caspases in hemocytes of M. domestica and D. melanogaster, respectively. Zn2+ also decreased the viability of hemocyte mitochondria but only in D. melanogaster. It suggests that flies use different pathways of PCD, or that Zn plays a different role in this process in M. domestica than in D. melanogaster. 相似文献
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J. Gessner L. Debus J. Filipiak S. Spratte K.E. Skora G.M. Arndt 《Zeitschrift fur angewandte Ichthyologie》1999,15(4-5):136-141
The data of sturgeon catches in German and adjacent waters since 1980 have been collected from the major river systems and coastal waters in Germany and neighbouring countries. Over the past 10 years records on catches of exotic sturgeon species increasingly occur in the commercial and recreational fisheries, including the following species: Acipenser baerii, A. gueldenstaedtii as well as hybrids from different parental species such as H. huso x A. ruthenus, A. baerii x A. ruthenus. A total of 227 records are reported, including data on their distribution. Accidental or deliberate introductions of sturgeons have been mediated by aquaculture and/or petfish-industries. Their occurrence is discussed in relation to plans for the re-establishing of the native A. sturio. 相似文献
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Margaret L. Van Keuren Galina B. Gavrilina Wanda E. Filipiak Michael G. Zeidler Thomas L. Saunders 《Transgenic research》2009,18(5):769-785
Transgenic mice are widely used in biomedical research to study gene expression, developmental biology, and gene therapy models.
Bacterial artificial chromosome (BAC) transgenes direct gene expression at physiological levels with the same developmental
timing and expression patterns as endogenous genes in transgenic animal models. We generated 707 transgenic founders from
86 BAC transgenes purified by three different methods. Transgenesis efficiency was the same for all BAC DNA purification methods.
Polyamine microinjection buffer was essential for successful integration of intact BAC transgenes. There was no correlation
between BAC size and transgenic rate, birth rate, or transgenic efficiency. A narrow DNA concentration range generated the
best transgenic efficiency. High DNA concentrations reduced birth rates while very low concentrations resulted in higher birth
rates and lower transgenic efficiency. Founders with complete BAC integrations were observed in all 47 BACs for which multiple
markers were tested. Additional founders with BAC fragment integrations were observed for 65% of these BACs. Expression data
was available for 79 BAC transgenes and expression was observed in transgenic founders from 63 BACs (80%). Consistent and
reproducible success in BAC transgenesis required the combination of careful DNA purification, the use of polyamine buffer,
and sensitive genotyping assays. 相似文献
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