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排序方式: 共有101条查询结果,搜索用时 15 毫秒
1.
S S Markina L A Favorova A V Solodovnikova I N Lineva L K Polikarpova 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1978,(7):52-56
Corynephage distribution was studied in the nasopharyngeal washings of 252 persons infected with C. diphtheriae of gravis type, toxigenic (21 patients and 147 carriers) and non-toxigenic ones (84 carriers), and in 468 uninfected persons in collective bodies under different epidemic conditions. Corynephages were isolated from the nasopharyngeal washings only in persons infected with toxigenic C. diphtheriae--in 4 (of 21) patients, and in 21% (of 147) carriers. Phages tox+ (4--6.2%) were revealed only in carriers of toxigenic C. diphtheriae with numerous bacteria in the nasopharynx and in diphtheria patients. Carriers of nontoxigenic diphtheria bacilli can become infected with phage tox+ only together with the toxigenic strains (reinfection). The data obtained indicated that toxigenic and nontoxigenic C. diphtheriae strains were individual variants. 相似文献
2.
Mitochondrial DNA evolution in the genus Equus 总被引:7,自引:0,他引:7
Employing mitochondrial DNA (mtDNA) restriction-endonuclease maps as the
basis of comparison, we have investigated the evolutionary affinities of
the seven species generally recognized as the genus Equus. Individual
species' cleavage maps contained an average of 60 cleavage sites for 16
enzymes, of which 29 were invariant for all species. Based on an average
divergence rate of 2%/Myr, the variation between species supports a
divergence of extant lineages from a common ancestor approximately 3.9 Myr
before the present. Comparisons of cleavage maps between Equus przewalskii
(Mongolian wild horse) and E. caballus (domestic horse) yielded estimates
of nucleotide sequence divergence ranging from 0.27% to 0.41%. This range
was due to intraspecific variation, which was noted only for E. caballus.
For pairwise comparisons within this family, estimates of sequence
divergence ranged from 0% (E. hemionus onager vs. E. h. kulan) to 7.8% (E.
przewalskii vs. E. h. onager). Trees constructed according to the parsimony
principle, on the basis of 31 phylogenetically informative restriction
sites, indicate that the three extant zebra species represent a
monophyletic group with E. grevyi and E. burchelli antiquorum diverging
most recently. The phylogenetic relationships of E. africanus and E.
hemionus remain enigmatic on the basis of the mtDNA analysis, although a
recent divergence is unsupported.
相似文献
3.
Russian Journal of Marine Biology - This study examines the effect of copper (100 and 200 μg/L) on the cell number dynamics, cell size and ultrastructure, chlorophyll a fluorescence,... 相似文献
4.
The consequence of harvesting young leaves of cassava as vegetable on the vulnerability of the crop to cassava mosaic disease (CMD) and on storage root yield was investigated using 30 cassava genotypes planted in IITA fields located in the humid forest (Port Harcourt?:?Onne), forest-savannah transition (Ibadan), southern guinea savannah (Mokwa) and northern guinea savannah (Zaria) agroecologies in Nigeria. Tender apical leaves and shoots of the cassava genotypes were removed from forty plants per cassava genotype with the same number of plants considered as control. Whitefly infestation, disease incidence (DI) and symptom severity (ISS) of the disease were assessed at monthly interval for six months and also at the ninth month after planting (MAP). Yield reduction due to this treatment was calculated as percentage harvest index (HI). Whitefly population fluctuated throughout the period of observation at all locations with higher population obtained generally for treated plants compared to control plants. Sprouting leaves of some treated genotypes were observed with severe mosaic symptoms, while corresponding control showed no mosaic symptoms. Contrarily, no remarkable difference was observed in Zaria between the mean ISS of treated and control cassava genotypes. There was a highly significant difference (P?<?0.01) in DI and ISS among cassava genotypes across all locations. Also, there was a highly significant interaction (P?<?0.01) in symptom severity between location (loc) and genotype, genotype and treatment (trt), loc and trt. Interaction between loc, genotypes and trt with regard to DI was highly significant at 2, 3 and 4 MAP, while with ISS, the interaction was highly significant all through the counting period. There was a positive relationship between DI and ISS on plants of genotypes 96/1039 and ISU. The percentage HI (27.4) of treated plants of genotype 95/0166 in Ibadan was remarkably lower than the value obtained for corresponding control (41.9) plants. Also, sharp distinction in% HI of treated (39.5) and control (43.8) ISU was observed in Onne with their respective ISS values as 3.7 and 3.2. Therefore, harvesting tender apical leaves and shoots of cassava as vegetables should be discouraged as it increases the severity of CMD infection in the regenerating shoots of cassava with attendant storage root yield reduction. 相似文献
5.
Markina OA Iastrebova NE Vaneeva NP Liashova VN 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》2004,(5):76-80
Cryptogenic fibrosing alveolitis (CFA) is a severe autoimmune disease of unclear etiology and prognostically unfavorable. The complexity of the diagnostics of this disease makes it necessary to search for new methods; for this reason immunity in CFA patients must be studied. The study of humoral organ-specific, organ-unspecific and antibacterial immunity of CFA patients revealed that the latter differed from the members of the groups used for comparison by a higher frequency of positive reactions in EIA determinations of IgG antibodies to cytokeratin-8 and Moraxella catarrhalis antigens. In addition, only in CFA patients a high degree of correlation (r=0.88) between these results was established. This made it possible to propose to use these reactions for confirming the diagnosis of CFA and suggested the probable role of M. catarrhalis in triggering autoimmune reactions characteristic of this disease. 相似文献
6.
Salonin DV Perepelkina OV Markina NV Gichenok IA Kuznetsova GD Poletaeva II 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》2004,54(2):277-282
The remote effects of neonatal (on the 3d-to-9th postnatal days) ketamine injections (10 and 50 mg/kg in 20 microliters of distilled water, s.c.) were analyzed in adult Wistar, WAG/Rij, and KM (a strain with high audiogenic sensitivity) rats. Both ketamine and water injections increased pain sensitivity in adult rats. Neonatally injected water increased the mean score of seizures in Wistar and WAG/Rij, whereas ketamine water solution injected in the dose of 50 mg/kg did not change the seizure intensity (as compared to the intact control). Consequently, ketamine significantly reduced the mean score of the audiogenic seizure fit without change in its latency. In highly sensitive KM rats the neonatally injected ketamine (50 mg/kg) significantly shortened the mean latency of the fit onset, and fit stages developed faster. Thus, the neonatal ketamine injection increased the audiogenic seizure susceptibility of brain structures in KM rats. 相似文献
7.
8.
The study deals with the effect of changes in salinity from 32 to 4‰ (at an interval of 4‰) on the growth, chlorophyll a and
carotenoid contents, and cell size of the benthic alga Attheya ussurensis (Bacillariophyta). A. ussurensis showed high tolerance to reduced salinity and ability to adapt to salinity changes from 16 to 12‰. In this salinity range,
the cells restored their shapes, sizes, and physiological functions. The number of cells and photosynthetic pigment content
were highest at a salinity reduction to 24‰. At 8‰, algal cells remained alive, but the process of cell division was inhibited; as a result,
the number of cells was significantly lower than in the control, the cells did not restore their sizes and shapes and remained
deformed until the end of the experiment. A drop in salinity to 4‰ caused a complete loss of cell viability of A. ussurensis within a day of exposure to this factor. 相似文献
9.
I. I. Poletaeva O. V. Perepelkina O. S. Boyarshinova I. G. Lil’p N. V. Markina T. B. Timoshenko A. V. Revishchin 《Russian Journal of Developmental Biology》2012,43(6):319-331
Experimental data were reviewed which demonstrated that the neonatal injection effects of certain biologically active drugs (ACTH4?C10 fragment and its analogue Semax, piracetam, caffeine, levetiracetam, busperone, etc.) could be detected in adult animals as changes in physiological and behavioral reactions and in several morphological traits as well. Audiogenic seizures proneness, anxiety-fear and exploration behavior as well as pain sensitivity were analyzed. The remote effects discovered were either similar in direction to those applied to an adult organism, or opposite to it. Pharmacological treatments of such type presumably interfere the CNS development during early postnatal ontogeny and change the normal pattern of brain development. These modulatory influences could be due to changes in neurotransmitter system development and are presumably capable to induce CNS morphological deviations (numbers of neurons, adult neurogenesis). 相似文献
10.
The effect of kanamycin on the electrophysical parameters of cell suspensions of Escherichia coli K-12 and pMMB33 was investigated. Incubation of the sensitive K-12 strain with kanamycin resulted in significant changes in the orientation spectra (OS) of the cell suspensions; these changes were not revealed in the case of the resistant pMMB33 strain. In the case of the sensitive K-12 strain incubated with different kanamycin concentrations, changes in the OS of the cell suspensions occurred within the 10–1000 kHz frequency range of the orienting electrical field. The most pronounced change in the electrooptical signal was observed at 10 μg/ml of kanamycin. Control experiments were carried out by standard plating on nutrient media. Thus, the OS changes of suspensions in the presence of antibiotics may be used as a test for microbial resistance to such antibiotics. 相似文献