Relationship between the presence of microfilaments and the cell cycle of HeLa cells in synchronus culture]

Some cytoplasmic organelles have showed characteristic variations which are related to the different cell cycle phases, in thymidine synchonized HeLa cells in culture. In these cells, the most modified organelles were intracytoplasmic membranes (endoplasmic reticulum) and microfilament arrangements. Microfilaments were numerous under the cell membrane, but also some of them were dispersed in dense bundles. These structures were seen around the nucleus, 12-14 h after removal of excess thymidine (G1). They migrated to the periphery of the cell during S and G2. During mitosis, they were directly under superficial membrane-associated microfilaments.     

Obtaining purified preparations of individual Shigella newcastle K- and O-antigens by using an ultracentrifugation method]

A modified method of obtaining the purified K- and O-antigens of Sh. newcastle with the use of ultracentrifugation is described. Serologically individual K- and O-antigens were obtained and their chemical composition was studied. Polysaccharide of the K-antigen consisted of the galacturonic acid, galactose, glucose, rhamnose xylose and hexosamine; it contained no heptoses. The O-antigen contained galactose, glucose, mannose, rhamnose, heptose and hexosamine; in difference to K-antigen was equal to 150000--160000. Thus, the K- and the O-antigen differed not only in the electrophoretic and diffuse mobility and immunological specificity, but also in the chemical composition.     

Relationship between the virulence of a culture and the presence of common (non-type-specific) antigens in strains of group A streptococcus of different types]

In studying common (nontypespecific) antigens sensitivity to trypsin there was shown their wide distribution among the cultures of streptococcus, group A, belonging to different types and containing M-proteins. The antigen No. 1, identical to one of the antigens of the thermostable fraction was found in the cultures, irrespective of the degree of their virulence. The antigen No. 2 was characteristic of only virulent cultures obtained after the increase of the virulence and forming matt-form colonies. Both of the antigens were referred to the category of R-antigens. The presence of the nonspecific antigens in the hydrochloric extracts should be taken into consideration in typing streptococci of group A and determination of M-antigens.     

Relationship between the quality of the inoculum material and carminomycin biosynthesis by a culture of Actinomadura carminata]

The effect of the inoculum mycelium quality on carminomycin biosynthesis by Actinomadura carminata was studied. The time of the organism growth on the culture medium containing cornsteep liquor continued for 6 hours without losing by the inoculum of its seeding qualities during that period. The mycelium growth in the inoculum was more intensive under conditions of moderate aeration, i.e. 0.98-2.64 mg O2H1-min. Anincrease in the aeration rate up to 18.56 mg O2/1-min resulted in the growth suppression up to 40 per cent. No correlation between the aeration rate during the inoculum growth and the culture capacity for carminomycin biosynthesis and of the content of the complex in active components the fermentation medium were observed, when a 5-10 per cent of inoculum was used.     

Relationship between the culture medium and the fatty acid composition of diphtheria and non-pathogenic corynebacteria]

The gasochromatic method was applied to the study of the cellular fatty acids composition in diphtheria and nonpathogenic corynebacteria (diphtheroids and psendo diptheria bacillus). Marked differences in the content of unsaturated fatty acids were revealed in them. Thus, palmito leic acid served the preponderant unsaturated fatty acid in Corynebacteria diphtheriae, and unsaturated fatty acids with 18 carbon atoms (octadeconoic and linoleic)--in nonpathogenic corynebacteria. The mentioned changes permit use this sign as differential. When grown on Loeffler's medium all the corynebacteria under study had a similar fatty acid composition characterized by the prevalence of unsaturated fatty acids with 18 carbon atoms. On the basis of studying the fatty acid spectrum of the nutrient media used it is supposed that one of the factors determining the revealed dependence of the corynebacterial fatty acid composition on the culture medium was the fatty acid composition of the latter.     

Relationship between death-feigning behavior and population density in a beetle

Journal of Ethology - Death feigning is an anti-predator behavior that is found in many animal taxa. Death feigning is thought to inhibit further attacks by predators and reduce the perceived need...     

Relationship between mRNA stability and intron presence

Introns were found to enhance almost every steps of gene expression except increasing mRNA stability. By analyzing the genome-wide data of mRNA stability published by someone previously, we found that human intron-containing genes have more stable mRNAs than intronless genes, and the Arabidopsis thaliana genes with the most unstable mRNAs have fewer introns than other genes in the genome. After controlling for mRNA length, we found mRNA stability is still positively correlated with intron number in human intron-containing genes. But in yeast Saccharomyces cerevisiae, two different datasets on mRNA half-life gave conflicting results. The components of messenger ribonucleoprotein particles recruited during intron splicing may be retained in cytoplasmic mRNPs and act as signals of mRNA stability or simply insulators to avoid mRNA degradation.     

Relationship between culture redox potential and culture fluorescence inCorynebacterium glutamicum

Summary Transient experiments were performed during a batch fermentation ofCorynebacterium glutamicum ATCC 14296 in which the flow of air to the reactor was cut off. The fluorescence of the culture was observed to vary linearly with the culture redox potential during the transient. This observation was made below the sensitivity limit of a dissolved oxygen probe. It appears that redox potential in conjunction with fluorescence measurements are of utility in studying extra- and intracellular reduction states, particularly in the microaerobic regime.     

Effect of leukocyte pyrogen on the phagocytic properties of macrophages in tissue culture]

The effect of rabbit leukocytic pyrogen (LP) on the phagocytic activity of the peritoneal macrophages of albino mice against shigellae was investigated. The dose-effect dependence was revealed: high LP doses depressed the phagocytosis, and low ones were insufficiently effective; addition of average LP doses against the kanamycin background stimulated both the absorption phase and that of shigella digestion. Phagocytosis stimulation with LP was also accompanied by an increase of the acid phosphatase lysosomal enzyme activity in macrophages; the RNA content was not changed.     

The partitioning behavior of K-562 cells associated with different stages of culture growth

Partitioning behavior of cells in dextran-poly(ethylene glycol) aqueous phase systems is a sensitive reflection of the cells' surface properties. A decrease in partition ratio, in charge-sensitive phases, of a variety of cell lines as a function of culture growth has been reported by a number of investigators. The basis for this phenomenon remains unclear. We have now studied the surface properties of K-562 cells (a human cell line originally derived from a patient with chronic myelogenous leukemia in blast crisis) during suspension culture growth by countercurrent distribution. The mean partition ratio of viable cells remained constant during 220 h of culture (i.e., well into stationary phase). The decrease in mean partition ratio of the cell population as a whole during culture, previously observed and reported by others, is attributed to the lower partition ratio of non-viable cells which increase with time of culture.     

Relationship between the structure and activity of a histamine-blocking serum glycoprotein]

A plasmatic glycoprotein is submitted to a mild periodate oxydation and its pharmacological activity is studied. This glycoprotein contains much N acetyl Neuraminic Acid (NANA = 15 p. cent), and it reduces the biological activity of histamine on smooth muscle such as guinea pig ileum. See article. We also identify the 8 NANA and 7 NANA derivaties. Th only 8 carbon derivative is obtained when about one mole of m-periodate is consumed for one mole of NANA. The 7 carbon derivative appears as soon as the consumption of a second mole leads ta a second cleavage. These results prove that the oxydation islimited to the sole N acetyl neuraminic acid and more precisely to the lateral polyhydroxylic chain. Under these conditions, pharmacological activity gradually decreases, it disappears as soon as the lateral polyhydroxylic chain is completely cut off.     

An experimental study of a lactoglobulin preparation against opportunistic bacteria and salmonellae]

A preclinical study of seven batches of lactoglobulin, a new biological preparation against opportunistic bacteria and salmonellae, has been carried out. High antibacterial activity of the preparation with respect to the virulent forms of Salmonella typhimurium, Salmonella enteritidis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus vulgaris, Proteus mirabilis has been established. The preparation has been shown to be safe and nontoxic. The 4-year term of its storage at a temperature of 6 degrees +/- 4 degrees C has been substantiated.     

Reparation of the damages induced by UV light in salmonellae]

The survival of Salmonella typhimurium wild type strains after UV-irradiation is studied. It is demonstrated that many of these are more sensitive to UV-irradiation than Escherichia coli of the wild type. Alkaline sucrose density gradient centrifugation has demonstrated a deficiency of these strains in normal excision repair of UV-damaged DNA. This deficiency is not a feature of Salmonella genus, because a strain is found of the same resistance and reparation ability as E. coli wild type strain.     

Structure of the antibiotic resistance of the salmonellae found in Transcarpathia]

Resistance of 1280 strains of Salmonella of various serological types isolated in the Zakarpatskaya region within 1967-1976 was studied with respect to benzylpenicillin, streptomycin tetracycline, levomycetin, monomycin, neomycin, erythromycin and oleandomycin. An Increase in the resistance of Salmonella to streptomycin, tetracycline, levomycetin, monomycin and neomycin was shown. During the last years Salmonellae carrying 4-8 resistance determinants were spreading in the region. Among S. typhimurium strains with 7-8 resistance determinants predominated (58.8 per cent). The cases of salmonollosis were mainly due to these strains.     

Yeast NaRNA as a stimulator of the virulence, immunogenicity and antigenicity of salmonellae]

Experiments on a great number of animals with the use of various methods showed that yeast NaRNA was capable of stimulating the increase of virulence, immunogenicity and antigenicity in S. typhi, the acceleration of their proliferation and growth, the accumulation of RNA and nucleotides without increasing their toxigenicity.