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Biomedical subjects

S Razin

Publications and source records attributed to S Razin.

At least 145 records · Page 8Linked to original sources
PubMed1968

Physiological and serological comparisons among strains of Mycoplasma granularum and Mycoplasma laidlawii.

Mycoplasma granularum strains grew on a medium devoid of animal serum or of serum fractions containing sterols; all strains possessed properties, including carotenoid biosynthesis, similar to those described for M. laidlawii. Some common antigenic components were noted among M. granularum and M. laidlawii strains by indirect fluorescent-antibody tests. The growth of M. granularum strains was slightly inhibited by antiserum to M. laidlawii PG-8, and the electrophoretic patterns of cell proteins of the M. granularum strains showed a close resemblance to that of M. laidlawii. However, direct fluorescent-antibody procedures performed on colonies grown on a serum-free medium clearly distinguished M. granularum from M. laidlawii. The occurrence of nonsterol-requiring mycoplasmas, in addition to M. laidlawii, raises questions as to the taxonomy of M. granularum and of the saprophytic mycoplasmas in general.

Animals↗
PubMed1968

Amino acid transport in Mycoplasma.

The uptake of l-histidine by Mycoplasma fermentans and l-methionine by M. hominis was found to be dependent on temperature and pH and to follow saturation kinetics. Several metabolic inhibitors inhibited this uptake. The transport system for l-methionine was highly specific. The l-histidine transport system was less specific, and the uptake was competitively inhibited by l-arginine and l-lysine. l-Histidine accumulated in the intracellular pool of M. fermentans at a concentration about 200 times that found in the medium. Efflux of accumulated l-histidine was demonstrated at 37 C, but not at 0 C. The rate of efflux was greatly accelerated by addition of l-histidine to the medium. The findings indicate that the Mycoplasma cell membrane contains specific transport systems resembling the permease systems of other microorganisms.

Acetates↗
PubMed1968

Mycoplasma taxonomy studiedy electrophoresis of cell proteins.

The electrophoretic patterns of cell proteins in polyacrylamide gels were used for the study of several taxonomic problems in the Mycoplasmatales. The patterns of five Mycoplasma hominis strains showed marked differences that corresponded with their known serological and nucleic acid heterogeneity. The patterns of three M. mycoides var. mycoides strains isolated in different countries were essentially identical. The electrophoretic patterns of several caprine strains resembled those of M. mycoides var. mycoides, supporting their classification as M. mycoides var. capri. Strain B3, a swine isolate, accordingly was tentatively identified as M. mycoides var. capri. The bovine mastitis strain M. agalactiae var. bovis possessed a pattern basically similar to that of the goat mastitis strain M. agalactiae, supporting the inclusion of both strains in one species. Three M. pulmonis strains isolated from rats or tissue cultures showed nearly identical patterns. The pattern of the toxigenic M. neurolyticum (Sabin A) strain resembled but was not identical with that of the nontoxigenic PG28 strain. The avian Mycoplasma species, M. gallisepticum, M. meleagridis, M. synoviae, M. gallinarum, and M. iners showed easily distinguishable and specific patterns, supporting their present classification in different species. Several improvements in the electrophoretic technique are described, and its advantages and limitations as a taxonomic tool are discussed.

Animals↗
PubMed1967

Electrophoretic patterns of membrane proteins of Mycoplasma.

Cell membranes of Mycoplasma were isolated either by osmotic lysis or by ultrasonic disruption of the organisms. The membranes were dissolved in phenol-acetic acid-water (2:1:0.5, w/v/v), and membrane proteins were separated electrophoretically in polyacrylamide gels containing 5 m urea and 35% (v/v) acetic acid. The electrophoretic patterns of membrane proteins were highly specific for the different Mycoplasma strains examined. The use of this method to prove the identity or dissimilarity of Mycoplasma strains is suggested.

Bacterial Proteins↗
PubMed1967

Identification of Mycoplasma and other microorganisms by polyacrylamide-gel electrophoresis of cell proteins.

The proteins of Mycoplasma cells of various species produce highly reproducible and species-specific electrophoretic patterns in polyacrylamide gels containing 5 m urea and 35% acetic acid. These electrophoretic patterns can be used for the rapid identification and classification of Mycoplasma. Preliminary results indicate that this method may also be used for the identification and classification of other microorganisms.

Amides↗
PubMed1966

Influence of lipid components of Mycoplasma laidlawii membranes on osmotic fragility of cells.

Razin, S. (University of Connecticut, Storrs), M. E. Tourtellotte, R. N. McElhaney, and J. D. Pollack. Influence of lipid components of Mycoplasma laidlawii membranes on osmotic fragility of cells. J. Bacteriol. 91:609-616. 1966.-Lipid composition of Mycoplasma laidlawii membranes could be significantly changed by variations in the growth medium. The effect of these changes on the osmotic fragility of the cells was studied. Cholesterol, incorporated into the membrane from the growth medium, had no significant effect on osmotic fragility. Carotenoids, synthesized by the cells from acetate, were likewise without effect. Unsaturated long-chain fatty acids increased markedly the resistance of M. laidlawii to osmotic lysis and promoted growth. The fatty acids of the growth medium were incorporated mainly into membrane phospholipids. The ratio between saturated and unsaturated fatty acids in membrane lipids depended on that of the growth medium.

Acetates↗
PubMed1966

Growth phases of Mycoplasma in liquid media observed with phase-contrast microscope.

Razin, Shmuel (University of Connecticut, Storrs), and Benjamin J. Cosenza. Growth phases of Mycoplasma in liquid media observed with phase-contrast microscope. J. Bacteriol. 91:858-869. 1966-Growth of 11 Mycoplasma strains in liquid media was followed by phase-contrast microscopy. A similar pattern of development was common to all strains. Branching filaments, 0.3 to 0.4 mu thick, characterized the early logarithmic phase of growth. The length of the filaments varied according to the strain tested and the growth medium. Addition of oleic acid to the medium induced the formation of very long filaments by M. laidlawii strain B. Upon aging, the filaments were found to break up into chains of coccoid elements. These chains further fragmented to yield shorter chains and single coccoid elements, which characterized the stationary and decline phases of growth. The size of the coccoid elements increased from 0.3 to 0.4 mu, when formed in the filaments, to 0.6 to 0.8 mu after being released from the chains. Further increase in the size of the cells took place at the decline phase of growth, leading to the formation of very large cells reaching a diameter of 10 to 20 mu. However, these large cells had the appearance of empty vesicles and were apparently nonviable as indicated by viable-count experiments.

Culture Media↗
PubMed1966

Adenosine triphosphatase activity of mycoplasma membranes.

Rottem, Shlomo (Hebrew University, Jerusalem, Israel), and Shmuel Razin. Adenosine triphosphatase activity of mycoplasma membranes. J. Bacteriol. 92:714-722. 1966.-Adenosine triphosphatase activity of Mycoplasma laidlawii, M. gallisepticum, and Mycoplasma sp. strain 14 was confined to the cell membrane. The enzymatic activity was dependent on magnesium, but was not activated by sodium and potassium. Ouabain did not inhibit the adenosine triphosphatase activity of the mycoplasmas, and did not interfere with the active accumulation of potassium by M. laidlawii cells. Sulfhydryl-blocking reagents and fluoride inhibited the enzymatic activity, whereas 2,4-dinitrophenol was without any effect. Membranes of M. laidlawii hydrolyzed other nucleotide triphosphates and adenosine diphosphate (ADP), but at a lower rate than adenosine triphosphate (ATP). Nucleoside-2'-(3')-phosphates, ribose-5-phosphate, glucose-6-phosphate, and pyrophosphate were not hydrolyzed by the membrane preparations. It seems that the enzyme(s) involved in ATP hydrolysis by M. laidlawii membranes is strongly bound to the membrane subunits, which would account for the failure to purify the enzyme by protein fractionation techniques. The adenosine triphosphatase activity of mycoplasma membranes resembles in its properties that of similar enzymes studied in bacteria. The mycoplasma enzyme(s) seems to differ from the adenosine triphosphatase associated with ion transport in mammalian cell membranes and from mitochondrial adenosine triphosphatase.

Adenosine Triphosphatases↗