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Biomedical subjects

R W Jackson

Publications and source records attributed to R W Jackson.

At least 127 records · Page 7Linked to original sources
PubMed1971

Bacteriolysis and inhibition of gram-positive bacteria by components of Streptococcus zymogenes lysin.

The ability of the A and L components of Streptococcus zymogenes lysin to cause lysis or to inhibit growth of a variety of gram-positive bacteria has been examined. Frank lysis of some, but not all, strains of S. faecalis, S. faecium, and S. liquefaciens by L component alone was demonstrated. None of the strains of these species was lysed by A component alone. S. durans was not lysed by either component. Inhibition of growth of all enterococcal strains by both A substance-producing and L substance-producing mutants of S. zymogenes was also demonstrated. However, inhibition by the A substance producer was markedly less than by the L substance producer. Inhibition of the growth of a number of other gram-positive genera by both A and L mutants was also noted.

Bacteriological Techniques↗
PubMed1971

Characterization of the A component of Streptococcus zymogenes lysin.

By utilizing conventional techniques of pressure ultrafiltration, gel filtration chromatography, diethylaminoethyl cellulose chromatography, and preparative polyacrylamide electrophoresis, the A component of the group D lysin produced by Streptococcus zymogenes has been purified to a state of apparent homogeneity when determined by the techniques of anionic and cationic disc gel electrophoresis. The A component was found to be a protein possessing a molecular weight of 27,000, a sedimentation coefficient approximating 3.2S, and a net negative charge at physiological pH.

Amino Acids↗
PubMed1971

Purification and characterization of the L component of Streptococcus zymogenes lysin.

By utilizing conventional techniques of pressure ultrafiltration, gel filtration chromatography, diethylaminoethyl cellulose chromatography, and preparative polyacrylamide electrophoresis, the L component of the group D lysin produced by Streptococcus zymogenes strains has been purified to a state of homogeneity as determined by the techniques of disc-gel electrophoresis at pH 9.3 and 4.3 and isoelectric focusing. The L component was found to be a protein possessing a molecular weight of 11,000 with a slight net negative charge at physiological pH.

Amino Acids↗
PubMed1971

Effects of various drugs on hemolytic activity of Streptococcus zymogenes.

Drugs known to interrupt the chain of protein synthesis (streptomycin, chloramphenicol, ethidium bromide) appeared to affect production of the group D lysin by Streptococcus zymogenes by inhibiting growth. Drugs which block cell wall synthesis (vancomycin, bacitracin, d-cycloserine, and phosphonomycin) inhibited lytic activity by a mechanism independent of growth. Bacitracin appeared not to have a major effect on lysin production but elicited the production of an inhibitor of lytic activity.

Animals↗
PubMed1970

Use of a logistic function in expressing kinetic hemolysis data.

A method of rectifying sigmoidal kinetic hemolysis curves is described. The curves are described, within limits, by the equation t = K(l/1 - l)(1/n) where t is time, K is a constant, l expresses the degree of lysis, and l/1 - l is the ratio of lysed to unlysed cells. This description holds over a wide range of red cell and lysin concentrations, provided the conditions are not substrate limited and the lysin preparation is reasonably stable. Graphical solution of the logarithmic transformation of the equation yields straight lines, and the intercepts of these lines with time ordinates may be used to define a time of initial lysis or, under suitable conditions, a time of 50% lysis. The time of initial lysis is inversely related to the lysin concentration, and thus its reciprocal may be used to precisely define units of lytic activity.

Journal Article↗
PubMed1969

Bicomponent nature of lysin from Streptococcus zymogenes.

Nonlytic mutants of Streptococcus zymogenes X-14 were isolated after exposure to nitrosoguanidine. Cross-streaking of certain of these mutants on brain Heart Infusion (BHI) blood agar plates resulted in formation of spur-shaped zones of hemolysis at the junction of the two streaks. Two types of mutants were recognized. Both of these excreted into the medium substances which are nonlytic but which together produce lytic activity. These substances behaved as an enzyme with an activator. Hence, one mutant type appeared to produce an activator and the other the catalytic molecule. Active complexes were temperature-sensitive and were inhibited by some teichoic acids as is the parental type of lysin.

Bacteriological Techniques↗
PubMed1968

Bacteriocin (hemolysin) of Streptococcus zymogenes.

The sensitivity of Streptococcus faecalis (ATTC 8043) to S. zymogenes X-14 bacteriocin depends greatly on its physiological age. Sensitivity decreases from the mid-log phase on and is completely lost in the stationary phase. The sensitivity of erythrocytes to the hemolytic capacity of the bacteriocin showed considerable species variation. The order of increasing sensitivity was goose < sheep < dog < horse < human < rabbit. However, when red cell stromata were used as inhibitors of hemolysis in a standard system employing rabbit erythrocytes the order of increasing effectiveness was sheep < rabbit < human < horse < goose. When rabbit cells were used in varying concentrations with a constant hemolysin concentration, there was a lag of about 30 min, which for a given hemolysin preparation was constant for all red cell concentrations. Furthermore, the rate of hemolysis increased with increasing red cell concentration. If red cells are held constant and lysin varied, the time to reach half-maximal lysis varies directly with lysin but is not strictly proportional. Bacterial membranes were one to three orders of magnitude more effective than red cell stromata as inhibitors. The order of increasing effectiveness seems to be Escherichia coli < Bacillus megaterium < S. faecalis < Micrococcus lysodeikticus. In addition to membranes, a d-alanine containing glycerol teichoic acid, trypsin in high concentration, and deoxyribonuclease also inhibited hemolysis. Ribonuclease, d-alanine, l-alanine, dl-alanyl-dl-alanine, N-acetyl-d-alanine, N-acetyl-l-alanine did not inhibit hemolysis.

Animals↗
PubMed1966

Characteristics of the vegetative growth of Bacillus popilliae.

Growth characteristics of the insect pathogen, Bacillus popilliae Dutky, were studied by propagation in shaken flasks and in 2-liter fermentors. Maximal populations between 5 x 10(8) and 2 x 10(9) viable cells per milliliter of culture medium routinely were obtained in incubation periods of 18 to 24 hr at 30 C in a medium composed of 1.5% yeast extract, 0.6% K(2)HPO(4), and 0.2% glucose or trehalose. The carbohydrate required for growth in liquid media was fermented with the formation of 2 meq of acid per mmole of carbohydrate utilized; acid products ordinarily were not subsequently metabolized. B. popilliae is an aerobe, and the amount of growth obtained varied with aeration to an optimum at oxygen absorption rates of about 0.5. Maximal populations persist in a culture for periods of only 1 to 4 hr; cessation of growth was followed immediately by rapid death of cultures, so that less than 1% of the cells remained viable after 48 hr, and viability often was lost entirely by the end of 72 hr of incubation. No cytological evidence for spore formation was observed under any growth condition. Death was not associated with lysis of the cells, although extensive granulation ultimately occurred. Continuous neutralizaiton, augmented buffering, various techniques of dialysis, or slow feeding of the carbohydrate did not markedly alleviate the characteristic death of the cultures.

Acids↗
PubMed1966

Nature of a red cell sensitizing substance from streptococci.

Jackson, Robert W. (Purdue University, Lafayette, Ind.), and Merwin Moskowitz. Nature of a red cell sensitizing substance from streptococci. J. Bacteriol. 91:2205-2209. 1966.-A method for purifying a streptococcal antigen which sensitizes red cells to agglutination by antiserum is described. The antigen, when purified by this method, is almost exclusively composed of glycerophosphate and d-alanine. The ratio of alanine to glycerophosphate varies from 1:5 to 1:3. The glycerophosphate is polymerized and is thus a teichoic acid. The polyglycerophosphate appears to be the antigenic determinant for agglutination. d-Alanine is readily removed by mild base and appears to be necessary for the attachment of the teichoic acid to red cells. Quantitative removal of alanine does not affect the ability of the polymer to absorb antibody from serum.

Alanine↗
PubMed1965

Effect of antimicrobial agents on the milky disease bacteria Bacillus popilliae and Bacillus lentimorbus.

The effects of antibiotics, sulfonamides, and other antimicrobial agents on vegetative cultures of five strains of milky disease bacteria were compared with those on Bacillus subtilis Cohn emend. Prazmowski, Staphylococcus aureus Rosenbach, Sarcina lutea Schroeter, Escherichia coli (Migula) Castellani and Chalmers, Saccharomyces pastorianus Hansen, and Mucor ramannianus Moel. Similar numbers of viable cells of each organism were exposed to the test materials by use of an antibiotic-sensitivity disc method adapted from techniques recommended by the Food and Drug Administration in the Federal Register. The results suggest that vancomycin or ristocetin, as well as a few other materials, might be useful in controlling contamination either during culture of the fastidious milky disease bacteria or in large populations of vegetative cells undergoing treatment to induce sporulation. Inhibitory concentrations of vancomycin and ristocetin in shaken-tube tests were much lower than expected in comparison with results of sensitivity-disc tests on the milky disease bacteria. Sublethal concentrations of the two antibiotics elicited some morphological change in the bacteria.

Anti-Bacterial Agents↗
PubMed1965

Polymer-Producing Species of Arthrobacter.

Gasdorf, Helen J. (Northern Regional Research Laboratory, Peoria, Ill.), R. G. Benedict, M. C. Cadmus, R. F. Anderson, and R. W. Jackson. Polymer-producing species of Arthrobacter. J. Bacteriol. 90:147-150.1965.-Two slime-producing microorganisms, designated as NRRL B-1973 and NRRL B-1797, were isolated from a Guatemalan soil sample. Their morphological and physiological characteristics permit their assignment to the genus Arthrobacter. Both cultures produce a large amount of extracellular polysaccharide, the maximal amount being 1.4 g per 3 g of glucose. The carbohydrate constituents of B-1973 polysaccharide are galactose, glucose, and mannuronic acid; those of B-1797 are galactose, glucose, and glucuronic acid. The organisms are morphologically and physiologically alike. The differences between these two cultures and previously described species of Arthrobacter appear sufficient to designate a new species. The name Arthrobacter viscosus sp. n. is proposed.

Journal Article↗