Loss of CpG dinucleotides from DNA. VI. Methylation of mitochondrial and chloroplast genes

From nucleotide sequences of mitochondrial and chloroplast genes the probable frequency of the CpG----TpG + CpA substitutions was determined. These substitutions may indicate the level of prior DNA methylation. It was found that the level of this methylation is significantly lower in mitochondrial DNA (mtDNA) and chloroplast DNA (chDNA) than in nuclear DNA (nDNA) of the same species. The species (taxon) specificity of mtDNA and chDNA methylation was revealed. A correlation was found between the level of CpG methylation in nDNA, and mtDNA and chDNA in different organisms. It is shown that cytosine residues in CpG were not subjected to significant methylation in the fungi and invertebrate mtDNA and also in the algae chDNA. In contrast, the vertebrate mtDNA bears the impress of CpG-supression, which is confirmed by direct data on methylation of these DNA. Here the first data on the possible enzymatic methylation of the plant mtDNA and chDNA were obtained. It was shown that the degree of CpG-suppression in the 5S rRNA nuclear genes of lower and higher plants is significantly higher in the chloroplast genes of 4,5S and 5S rRNA. From data on pea chDNA hydrolysis with MspI and HpaII it was established that in CCGG sequences this DNA is not methylated. The role of DNA methylation in increasing the mutation rate and in accelerating the evolutionary rates of vertebrate mtDNA is discussed.     

Comparative study of different variants of Actinomyces roseoflavus producing the polyene antibiotic roseofungin

The respiration chain in the membranes of whole Actinomyces roseoflavus (var. roseofungini) cells from the parent and secondary cultures is sensitive to KCN, non-sensitive to Triton X-100 treatment removing the antibiotic roseofungin from the cells, and has a very high for the bacteria respiration control. When the cells are in contact with atomic tritium at the temperature of liquid nitrogen, roseofungin is tritiated and binds to A. roseoflavus isolated membranes and whole cells, mostly to those of the parent culture as compared to the secondary culture. A fraction of membranes which lost NADH dehydrogenase in the course++ of purification was isolated from the cells disintegrated in the frozen state.     

Myosin isoforms of the developing skeletal muscles in the loach

Changes in the myosin isozyme spectrum were studied in the loach developing skeletal muscle. It was shown using disk-electrophoresis in polyacrylamide gel and peptide mapping that light and heavy myosin chains from the larval muscles, as well as from the red and white muscle of adult fish differ from each other. Forms of myosin light and heavy chains were found which were characteristic of the larval muscle only.     

Cloning and expression of human nebulin cDNAs and assignment of the gene to chromosome 2q31-q32

We have isolated two nonoverlapping cDNAs encoding human nebulin, a muscle-specific protein. Northern hybridization analysis shows that nebulin is encoded by a huge message at least 25 kb in length. By hybridizing two nonoverlapping cDNAs to DNA isolated from rodent X human cell hybrids, we assign this presumably single-copy gene to human chromosome 2; sublocalization studies indicate that the nebulin gene is on the long arm of the chromosome, in the region 2q31-q32.     

除虫菊的染色体数目及其核型

除虫菊(Pyrethrum cinerariifolium Trev.)为菊科小黄菊属多年生宿根草本植物。以花或全草入药。除虫菊的主要有效成分为除虫菊酯和瓜叶除虫菊酯,可用于加工成各种制剂作杀虫剂原料,用以防治日常虫豸(蚊、蝇、虱等)和农业害虫,且对人     

应用蛋白印迹法检测鼻咽癌病人血清中抗Epstein—Barr病毒IgA/EA抗体

曾毅等建立了一系列检测EB病毒IgA/VCA和IgA/EA抗体的鼻咽癌早期诊断方法,取得了满意的结果。为了进一步提高对鼻咽癌诊断更为特异的IgA/EA抗体的检出率,我们建立了检测EB病毒IgA/EA抗体的蛋白印迹法。方法敏感特异,结果令人满意。 本法中所用的两个质粒系由本实验室与西德Pettenkofer研究所Wolf教授的实验室合作构建。pUCARG1140和pUC9MBcE3.2质粒均为表达质粒,前者携带着来源于EB病毒Bam     

Nomenclatural remarks on the association names ofNardus stricta-rich communities in Central Europe

The present paper gives comments on the nomenclature of associations ofNardetalia andNardo-Caricion rigidae from Central Europe. A brief list of important homonyms and ambiguous names is added.     

Restriction analysis of Thiobacillus ferrooxidans DNA using pulsed field electrophoresis]

The DNA of Thiobacillus ferrooxidans digested by any of the five restriction endonucleases (DraI, EcoRI, Eco321, HindIII, XbaI) was studied by electrophoresis in the pulsating differently directed electric fields (PF). The influence of PF conditions on the sized row of the divided DNA fragments was studied. Only the XbaI restriction endonuclease was shown to cleave the Thiobacillus ferrooxidans DNA into a number of fragments permitting one to define the sizes of fragments and genome (no more than 2300 bp). The prospects of using the restriction analysis of Thiobacillus ferrooxidans wild type culture for improving its properties in obtaining heavy metals are discussed.     

Comparative effectiveness of various antibiotics in the treatment of patients with meningococcal meningitis]

The results of treating 322 patients with various forms of meningococcal infection accepted to a hospital within a year are presented. The patients were divided into 3 groups by the character of etiotropic therapy. The patients of group I were treated with benzylpenicillin and those of group 2 were treated with levomycetin sodium succinate. Group 3 included the patients, the therapy of whom with the above two antibiotics failed and they were subjected to treatment with cefazolin, cefotaxime, amikacin and other broad spectrum antibiotics. Benzylpenicillin generally proved to be the drug of choice in the antibacterial therapy of meningococcal infection. In comparison to levomycetin (chloramphenicol) it provide more rapid clinical recovery of the patients and normalization of the indices of the cerebrospinal fluid. Only failure of benzylpenicillin therapy was considered as an indication to the broad-spectrum antibiotics to be in the complex treatment of the patients. As additional methods for estimating the efficacy of antibacterial therapy it was recommended to employ calculation of the integral indices of hemograms (the leukocyte index of intoxication and the hematologic index of intoxication).