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排序方式: 共有681条查询结果,搜索用时 15 毫秒
41.
N. I. Germogenov N. G. Solomonov A. E. Pshennikov A. G. Degtyarev S. M. Sleptsov N. N. Egorov I. P. Bysykatova M. V. Vladimirtseva V. V. Okoneshnikov 《Contemporary Problems of Ecology》2013,6(1):65-76
The structure of the distribution range and population of the Siberian crane in its regular breeding area in the northeastern Yakutian tundra are described, as well as the migration terms, intensity, routes, and stopover sites. The territorial pairs (71.7–97.1% of the summer population), which in 2006 were represented by the birds at ages of 8 to 21 years (mainly 20 years, accounting for 45.4%), constantly stayed on an area of 7.3–16.5 km2 independently of their participation in breeding. The breeding success in this population varies from 4.3–8.7 to 65.0–83.3% and depends on the climatic conditions at the beginning of egg laying; these climatic conditions change rather unpredictably from year to year, as well as being seasonally unstable. This explains that fact that some generations in this population are particularly vulnerable to natural elimination factors because of their low numbers. Bird migration in Yakutia follows a narrow tunnel with the highest migratory intensity in the Middle Aldan Valley. In the fall, 30 to 50% of the entire population is visually recorded there. 相似文献
42.
V. I. Fisinin L. A. Il’ina E. A. Iyldyrym I. N. Nikonov V. A. Filippova G. Yu. Laptev N. I. Novikova A. A. Grozina T. N. Lenkova V. A. Manukyan I. A. Egorov 《Microbiology》2016,85(4):493-499
Molecular genetic techniques (NGS sequencing and quantitative PCR) were used to determine the composition of the cecal bacterial community of broiler chickens fed with different mixed fodder. The cecal microbiome exhibited taxonomic diversity, with both typical inhabitants of avian intestine belonging to the families Clostridiaceae, Eubacteriaceae, and Lactobacillaceae and to the phylum Bacteroidetes, and new unidentified taxa, as well as bacteria of the families Lachnospiraceae and Ruminococcaceae, which were previously considered restricted to the rumen microbiota. Contrary to traditional concepts, enterococci and bifidobacteria were among the minor components of the community, lactate-fermenting species were absent, and typical avian pathogens of the genus Staphylococcus were detected but seldom. Members of the family Suterellaceae and the genus Gallibacterium, which are responsible for avian respiratory infections, were also detected. Significant fluctuations of abundance and composition of microbial groups within the cecal community and of the parameters of broiler productivity were found to occur depending on the feed allowance. Cellulose content in the feed had the most pronounced effect on the composition and structure of bacterial communities. Decreased cellulose content resulted in a decrease of bacterial abundance by an order of magnitude and in increased ratios of members of the phylum Bacteroidetes and the family Clostridiaceae, which possess the enzymes degrading starch polysaccharides. Abundance of the normal inhabitants of avian intestine belonging to the genus Lactobacillus and the order Bacillales decreased, while the share of Escherichia and members of the family Sutterellaceae increased, including some species capable of causing dysbiotic changes in the avian intestine. No significant change in the abundance of cellulolytics of the families Ruminococcaceae, Lachnospiraceae, and Eubacteriaceae was observed. 相似文献
43.
AP Shoko SM Limbu HA Lamtane MA Kishe-Machumu B Sekadende EE Ulotu 《African Journal of Aquatic Science》2019,44(1):15-24
Aquaculture practices from sub-Saharan Africa are characterised by low production, owing to improper technology. Production can be increased through integrating fish farming with other existing on-farm activities, particularly livestock husbandry. We assessed the role of fish-poultry integration on all male Nile tilapia, Oreochromis niloticus growth performance, yields and economic benefits among smallholder farmers in sub-Saharan Africa, Tanzania. The study also compared phytoplankton species composition, abundance and biomass between the fish-poultry integration and non-integrated system. After 180 days of the experiment, all male O. niloticus cultured under fish-poultry integration exhibited significantly higher growth rates than those in the non-integrated system (p < 0.05). Gross fish yield (GFY), net fish yield (NFY) and net annual yields (NAY) obtained from fish-poultry integration were significantly higher than those from non-integrated system (p < 0.05). Partial enterprise budget analysis revealed that fish-poultry integration was more profitable than the non-integrated system. Moreover, fish-poultry integrated system produced significantly higher phytoplankton abundance and biomass than those from the non-integrated system. Results demonstrate that rural smallholder farmers can achieve higher growth rate, farm net yields and income by integrating all male O. niloticus with other on-farm activities than practising a stand-alone fish culture system. 相似文献
44.
Kovalyova MA Kovalyov LI Shishkin SS Egorov TA Musalyamov AK 《Biochemistry. Biokhimii?a》1999,64(10):1108-1110
The partial amino acid sequence (23 amino acid residues) of a protein isolated from human atrium has been determined. The sequence homology shows that this protein belongs to the myosin 1 light chain family (an atrium-specific isoform). 相似文献
45.
Photosensitization of singlet oxygen formation by pterins and flavins. Time-resolved studies of oxygen phosphorescence under laser excitation 总被引:1,自引:0,他引:1
Egorov SY Krasnovsky AA Bashtanov MY Mironov EA Ludnikova TA Kritsky MS 《Biochemistry. Biokhimii?a》1999,64(10):1117-1121
To elucidate the biochemical roles of singlet molecular oxygen (1(O2)) in the light-dependent reactions photosensitized by biological blue-light photoreceptors, time-resolved measurements of photosensitized 1O2 phosphorescence (1270 nm) were performed in air-saturated aqueous ((D2)O) solutions of pterins (2-amino-4-hydroxy-6,7-dimethylpteridine (DMP) and 2-amino-4-hydroxy-6-tetrahydroxybutyl-(D-arabo)pteridine (TOP)) and flavins (riboflavin and flavin mononucleotide (FMN)) under excitation with nitrogen laser (337.1 nm) pulses. The 1(O2) quantum yields were found to be 0.16, 0.20, 0.50, and 0.50 for DMP, TOP, riboflavin, and FMN, respectively. The data indicate that pterins and flavins are rather efficient photosensitizers of 1(O2) production that might be important for their photobiological functions. 相似文献
46.
Arkblad EL Egorov M Shakhparonov M Romanova L Polzikov M Rydström J 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2002,133(1):13-21
Proton-translocating nicotinamide nucleotide transhydrogenase is located in the mitochondrial inner membrane and catalyzes the reduction of NADP(+) by NADH to NADPH and NAD(+). The present investigation describes the expression of the transhydrogenase gene in various mouse organs, subsections of the human brain and Caenorhabditis elegans. In the mouse, the expression was highest in heart tissue (100%) followed by kidney (64%), testis (52%), adrenal gland (41%), liver (35%), pancreas (34%), bladder (26%), lung (25%), ovary (21%) and brain (14%). The expression in brain tissue was further investigated in the human brain which showed a distribution that apparently varied as a function of neuronal density, a result that was supported by estimations of expression in C. elegans using Green Fluorescent Protein (GFP) controlled by the transhydrogenase promoter. GFP-expressing C. elegans lines showed a clear concentration of fluorescence to the gut, the pharyngeal-intestinal valve and certain neurons. It is concluded that the transhydrogenase gene is expressed to various extents in all cell types in mouse, human and C. elegans. 相似文献
47.
Shavva A. G. Vlasova K. V. Tsogoeva S. B. Egorov M. S. Yakutseni P. P. 《Russian Journal of Bioorganic Chemistry》2002,28(3):209-214
The complexes of the estrogen -receptor with estradiol and 8-isoestradiol were comparatively analyzed. The computations of ligand–receptor complexes, carried out using the FLEXX program, allowed us to propose a model for the binding of the analogues of 8-isoestradiol. It was found that rings Cand D of estradiol and 8-isoestradiol are similarly arranged in the ligand-binding pocket and coincide upon the superposition of the corresponding ligand–receptor complexes, whereas rings A and B do not coincide. The oxygen functions in position 17 of the estradiol analogues of both series coincide upon superposition, whereas the phenol 3-hydroxyl groups are 0.05 Å apart. A comparison of the predicted biological properties of modified estradiol analogues of the natural and 8-iso-series with the available experimental data revealed their similarity. Synthetic 2-acetyl analogues of 8-isoestrogens were found to have no uterotropic activity, which is also consistent with the proposed model. 相似文献
48.
Khoang NA Berezin BB Piskarev VE Iamskov IA Musaliamov AKh Egorov TsA 《Prikladnaia biokhimiia i mikrobiologiia》2003,39(1):122-126
The complete amino acid sequence of an important toxin (toxin 14) from the venom of a Vietnamese scorpion (Buthus occitanus sp.) has been determined, which includes 35 amino acid residues and three disulfide bridges (molecular weight, 3843 Da). The comparison of the sequence with sequences of short scorpion toxins led us to conclude that toxin 14 belongs to a novel group of toxins affecting the excitability of myelinated nerves. 相似文献
49.
Nuclear gene trees and the phylogenetic relationships of the mangabeys (Primates: Papionini) 总被引:3,自引:1,他引:2
Phylogenetic relationships of mangabeys within the Old World monkey tribe
Papionini are inferred from analyses of nuclear DNA sequences from five
unlinked loci. The following conclusions are strongly supported, based on
congruence among trees derived for the five separate gene regions: (1)
mangabeys are polyphyletic within the Papionini; (2) Cercocebus is the
sister taxon to the genus Mandrillus; and (3) Lophocebus belongs to a clade
with Papio and Theropithecus, with Papio as its most likely sister taxon.
Morphologically based phylogenies positing mangabey monophyly were
evaluated by mapping the sequences for each locus on these trees. The data
seem to fit these trees poorly in both maximum-parsimony and likelihood
analyses. Incongruence among nuclear gene trees occurred in the
interrelationships among Lophocebus, Papio, and Theropithecus. Several
factors that may account for this incongruence are discussed, including
sampling error, random lineage sorting, and introgression.
相似文献
50.
Extracts of pig kidneys or germinated soya beans after preliminary steps were affinity chromatographied on Sepharose containing cyanogen bromide immobilized monoclonal antibodies to pig insulin. The material bound to the affinity column was separated by HPLC resulting in one homogeneous protein from each source. Both proteins have been shown to inhibit DNA synthesis in cultured embryonic human fibroblasts and VERO fibroblasts. The effect of pig kidney protein was potentiated by insulin. Soya and pig proteins were characterized by the following parameters: molecular weights of 8.5 and 10.3 kD, apparent constants of dissociation with rat liver plasma membranes of 4.7 x 10(-8) M and 9.8 X 10(-8) M, respectively. The soya proteins competed for the binding sites on plasma membranes with insulin whereas the pig protein did not. The N-terminal amino acid sequences of 20 residues were determined for both proteins. Comparison of these sequences with known protein sequences was performed. A 30-40% primary structure homology of the studied fragment of soya bean protein with the fragments of some oncogenic viruses proteins and transforming proteins was revealed. 相似文献