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1.
The results of the phage typing of 5, 168 Staph. aureus strains isolated in a surgical hospital between 1959 and 1977 are analyzed for each year of this period. The wave of increase in the number of staphylococci belonging to phage group II which began, as discovered in this study, in 1965 and still showed no tendency towards decrease in 1977, as well as the periodicity of rises and falls in the number of staphylococci belonging to phage groups I and III are discussed and compared with the data contained in the literature. The authors come to the conclusion that Staph. aureus is subject to wave-like rises and falls in the number of strains belonging to the main phage groups of the species, and among them the strains belonging to phage groups I and III seem to be inversely related in respect of rises and falls in number, such changes occurring periodically at an interval of 10-12 years, while in the strains belonging to phage group II changes in number occur at a slower rate. The constant account of the percentage of phage groups I, II and III is recommended to ensure rational antibiotic therapy. 相似文献
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O. A. Kovaleva 《Cytology and Genetics》2008,42(1):48-59
Different types of cytogenetic anomalies used in classical cytogenetics for estimating the level of damage to the chromosome apparatus are considered. Possible causes for the occurrence of different types of cytogenetic anomalies as well as the range of methods of micronucleus testing are discussed. It is shown that different levels of organization of genetic material (nucleotide, chromosome, or suprachromosome material) have an effect on processes involved in realization of a defect in the nucleotide sequence into a cytogenetic anomaly. 相似文献
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Incubation of tryptophanyl-tRNA synthetase from bovine pancrease with [gamma-32P]ATP of [gamma-32P]GTP and casein kinase II from rabbit liver leads to the incorporation of labeled phosphate into serine residues of synthetase polypeptide. The maximal level of 32P incorporation into synthetase polypeptide (Mr = 60 kDa) 0.15 moles of 32P per 1 mole of polypeptide was observed. Electrophoretic analysis according to O'Farrell showed that kinase phosphorylates exclusively the most acidic polypeptides (pI 4.9) of the synthetase preparation. Pretreatment of synthetase with animal acidic and alkaline phosphatases had no influence on the level of 32P incorporation in synthetase during subsequent incubation in the presence of casein kinase II. 相似文献
7.
The aspartic proteinase of barley is a vacuolar enzyme that processes probarley lectin in vitro. 总被引:8,自引:1,他引:7
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Previous work suggested that the aspartic proteinase from Hordeum vulgare (HvAP) would be a vacuolar protein in plant cells. Based on N-terminal sequencing we show that the in vitro-translated protein was translocated into the lumen of microsomal membranes, causing a concomitant removal of 25 amino acid residues from the protein. Vacuoles were purified from barley leaf protoplasts and were shown to contain all of the aspartic proteinase activity found in the protoplasts. This vacuolar localization of HvAP was confirmed with immunocytochemical electron microscopy using antibodies to HvAP in both barley leaf and root cells. In an attempt to discern a function for this protease, we investigated the ability of HvAP to process the C-terminal proregion of barley lectin (BL) in vitro. Prolectin (proBL), expressed in bacteria, was processed rapidly when HvAP was added. Using several means, we were able to determine that 13 amino acid residues at the C terminus of proBL were cleaved off, whereas the N terminus stayed intact during this incubation. Immunohistochemical electron microscopy showed that HvAP and BL are co-localized in the root cells of developing embryos and germinating seedlings. Thus, we propose that the vacuolar HvAP participates in processing the C terminus of BL. 相似文献
8.
Nielsen J; Peixoto AA; Piccin A; Costa R; Kyriacou CP; Chalmers D 《Molecular biology and evolution》1994,11(6):839-853
The region of the clock gene period (per) that encodes a repetitive tract
of threonine-glycine (Thr-Gly) pairs has been compared between Dipteran
species both within and outside the Drosophilidae. All the non-
Drosophilidae sequences in this region are short and present a remarkably
stable picture compared to the Drosophilidae, in which the region is much
larger and extremely variable, both in size and composition. The
accelerated evolution in the repetitive region of the Drosophilidae appears
to be mainly due to an expansion of two ancestral repeats, one encoding a
Thr-Gly dipeptide and the other a pentapeptide rich in serine, glycine, and
asparagine or threonine. In some drosophilids the expansion involves a
duplication of the pentapeptide sequence, but in Drosophila pseudoobscura
both the dipeptide and the pentapeptide repeats are present in larger
numbers. In the nondrosophilids, however, the pentapeptide sequence is
represented by one copy and the dipeptide by two copies. These observations
fulfill some of the predictions of recent theoretical models that have
simulated the evolution of repetitive sequences.
相似文献
9.
Evolutionary origin of human and primate malarias: evidence from the circumsporozoite protein gene 总被引:8,自引:1,他引:7
We have analyzed the conserved regions of the gene coding for the
circumsporozoite protein (CSP) in 12 species of Plasmodium, the malaria
parasite. The closest evolutionary relative of P. falciparum, the agent of
malignant human malaria, is P. reichenowi, a chimpanzee parasite. This is
consistent with the hypothesis that P. falciparum is an ancient human
parasite, associated with humans since the divergence of the hominids from
their closest hominoid relatives. Three other human Plasmodium species are
each genetically indistinguishable from species parasitic to nonhuman
primates; that is, for the DNA sequences included in our analysis, the
differences between species are not greater than the differences between
strains of the human species. The human P. malariae is indistinguishable
from P. brasilianum, and P. vivax is indistinguishable from P. simium; P.
brasilianum and P. simium are parasitic to New World monkeys. The human P.
vivax-like is indistinguishable from P. simiovale, a parasite of Old World
macaques. We conjecture that P. malariae, P. vivax, and P. vivax-like are
evolutionarily recent human parasites, the first two at least acquired only
within the last several thousand years, and perhaps within the last few
hundred years, after the expansion of human populations in South America
following the European colonizations. We estimate the rate of evolution of
the conserved regions of the CSP gene as 2.46 x 10(-9) per site per year.
The divergence between the P. falciparum and P. reichenowi lineages is
accordingly dated 8.9 Myr ago. The divergence between the three lineages
leading to the human parasites is very ancient, about 100 Myr old between
P. malariae and P. vivax (and P. vivax-like) and about 165 Myr old between
P. falciparum and the other two.
相似文献
10.
The data on the clinical trials of karminomycin, a new antitumor antibiotic are presented. The drug was used in the treatment of 46 adult patients with leukemia. Karminomycin was used in primary inducing therapy and treatment of relapses. The results of the trials showed that karminomycin had a definite therapeutic activity in treatment of acute myeloblast leukemia at various stages of the process. A rapid effect of the antibiotic provided its use in emergency cases with rapidly progressing variants of the disease. 相似文献