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排序方式: 共有149条查询结果,搜索用时 15 毫秒
1.
In this paper the recent population changes of the Wild Boar in different European countries is analysed through the study of hunting statistics. A simultaneous increase in numbers is observed throughout the whole area during the period 1965–1975. From 1975 onwards the population stabilizes itself apart from in peripheral areas like Finland. Potentially favourable factors which play a part in this process are discussed and certain reproductive and dispersive characteristics which favour its invasive behaviour are discussed. 相似文献
2.
Marker-Dependent Recombination in T4 Bacteriophage. I. Outline of the Phenomenon and Evidence Suggesting a Mismatch Repair Mechanism 总被引:4,自引:1,他引:3
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V. P. Shcherbakov L. A. Plugina E. A. Kudryashova O. I. Efremova S. T. Sizova Oleg G. Toompuu 《Genetics》1982,102(4):615-625
In standard crosses, some rIIB mutants of T4 phage were found to be susceptible to an extra recombination mechanism to which the other mutants were much less susceptible. The following observations were interpreted as evidence for the mismatch-repair nature of the phenomenon: (1) Marker-dependent recombination generates exclusively double exchanges at both sides of the marker. (2) Marker-dependent recombination is highly sensitive to DNA base sequence at the site of the marker and to that at the corresponding site on the chromosome of the other parent. (3) Within certain limits, the contribution of the marker-dependent mechanism to the total recombination frequency is distance-independent and thus constitutes a constant component. 相似文献
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Smol'skaia TT Sizova NV Korovina GI Maslov VP Kevlova NA Novikova VA Bogoiavlenskiĭ GV 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1999,(1):57-59
The informatory role of a new marker of HIV infection, characterizing the content of HIV-1 RNA in the biological fluids of the patient's body, is evaluated. The quantitative determination of HIV-1 RNA, carried out in a single assay, was made in the blood of 25 HIV-infected patients. These studies confirmed that the determination of the level of RNA in the plasma (viral load) was a reliable criterion indicating the severity and progress of the disease. The viral load of more than 100,000 copies/ml was a sign prognosticating the future pronounced progress of the disease in spite of moderate clinical manifestations and relatively high values of CD4 cells in the patient's blood at the moment of testing. 相似文献
6.
Sizova OI Liubun' EV Kochetkov VV Validov ShZ Boronin AM 《Prikladnaia biokhimiia i mikrobiologiia》2004,40(1):78-82
Gene constructions rendering bacteria resistant to arsenic and capable of dissolving phosphates and/or arsenates were created by cloning ars operon and the gene of citrate synthase from a chromosome of the strain Pseudomonas aeruginosa PAO1. Genetically modified variants of the strain Pseudomonas aureofaciens BS1393 have been constructed, which are resistant to high concentrations of arsenic and dissolve poorly soluble phosphates and/or arsenates. Recombinant strains P. aureofaciens BS1393(pUCP22::arsRBC) and P. aureofaciens BS1393(pUCP22::gltA) exerted positive effects on the survival of sorgo (Sorghum saccharatum L.) and its ability to accumulate arsenic. 相似文献
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Synthesis of alpha-D-xylopyranosyl phosphate is carried out by a modified MacDonald method. 相似文献
9.
We developed a procedure to culture microorganisms below freezing point on solid media (cellulose powder or plastic film) with ethanol as the sole carbon source without using artificial antifreezes. Enrichment from soil and permafrost obtained on such frozen solid media contained mainly fungi, and further purification resulted in isolation of basidiomycetous yeasts of the genera Mrakia and Leucosporidium as well as ascomycetous fungi of the genus Geomyces. Contrary to solid frozen media, the enrichment of liquid nutrient solutions at 0 degrees C or supercooled solutions stabilized by glycerol at -1 to -5 degrees C led to the isolation of bacteria representing the genera Polaromonas, Pseudomonas and Arthrobacter. The growth of fungi on ethanol-microcrystalline cellulose media at -8 degrees C was exponential with generation times of 4.6-34 days, while bacteria displayed a linear or progressively declining curvilinear dynamic. At -17 to -0 degrees C the growth of isolates and entire soil community on 14C-ethanol was continuous and characterized by yields of 0.27-0.52 g cell C (g of C-substrate)(-1), similar to growth above the freezing point. The 'state of maintenance,' implying measurable catabolic activity of non-growing cells, was not confirmed. Below -18 to -35 degrees C, the isolated organisms were able to grow only transiently for 3 weeks after cooling with measurable respiratory and biosynthetic (14CO2 uptake) activity. Then metabolic activity declined to zero, and microorganisms entered a state of reversible dormancy. 相似文献
10.
Karpova OI Saccone S Varriale A Sizova TV Penkina MV Bogdanov IuF 《Molekuliarnaia biologiia》2004,38(4):668-675
The synaptonemal complex isolated from the spermatocyte nuclei by exhaustive hydrolysis of the latter by DNase II contains tightly associated DNA sequences (SCAR DNA). Here we studied the compositional properties of a cloned family of SCAR DNA of golden hamster, namely we performed the localization of 27 SCAR DNA clones on compositionally fractionated genomic DNA from golden hamster. We observed that sequences of the SCAR DNA family are mainly localized in the GC-poor isochore families L1 and L2, that showed 63% hybridization signals. This means that 37% of signals is referred to the GC-rich isochores, indicating the presence of SCAR DNA overall the genome, even if each isochore family presents differences in density and sequence type. Moreover, the SCAR DNA sequences containing regions of homology with LINE/SINE repeats were observed in all the isochore families. The compositional localization of SCAR DNA is in agreement with the hypothesis that SC and SCAR DNA participate in the chromatin organization during the meiosis prophase I, which should result in the attachment of chromatin loops to lateral elements of SC along the whole length of the latter. 相似文献