Publications

enchancement of streptococcal transformation yield by proteolytic enzymes.	trypsin and other proteolytic enzymes, added together with transforming dna or during cell-dna contact to competent cultures of several streptococcal strains, enchanced (10 to 600%) the yield of genetic transformation (stimulation). with few exceptions, the level of stimulation was high (over 100%) when competence was low (below 2%). stimulation was caused by the action of an enzyme on competent cells and not on any other component of transformation mixture. the phenomenon occurred when the enzy ...	1978	30748
mechanism of coaggregation between actinomyces viscosus t14v and streptococcus sanguis 34.	actinomyces viscosus t14v and streptococcus sanguis 34 coaggregate by a mechanism which is not inhibited by 1 m nacl, is dextran independent, requires calcium, is ph dependent with an optimum at ph 8.0 to 8.5, and appears to require the interaction of a protein or glycoprotein on a. viscosus with a carbohydrate on s. sanguis. the coaggregation is inhibited more than 80% by 0.01 m lactose, 0.02 m beta-methyl-d-galactoside, or 0.05 m d-galactose; inhibition of coaggregation was less than 10% in 0. ...	1978	30701
factors affecting the aggregation of actinomyces naeslundii during growth and in washed cell suspensions.	various factors affecting the aggregation of actinomyces naeslundii strain 12104 were studied. when the ph of glucose-supplemented growth medium fell below 5.5, the cells aggregated and formed microbial masses which tenaciously adhered to the culture vessels. when the organism was cultured in the same medium in the absence of glucose, maximum growth was reduced and the final culture ph values remained above 6.5, but the cells were more dispersed and nonadherent. adjusting the final ph of these c ...	1978	30700
bacteriocin-like activities of human dental plaque flora against oral anaerobic microorganisms.		1977	26477
specific inactivation of heterospecific transforming dna by a factor derived from streptococcus sanguis lysates.	a heat-sensitive factor obtained from lysates of competent streptococcus sanguis cells reacts specifically with native dna of heterospecific (s. pneumoniae or calf thymus) origin. in vitro it does not alter the double or single strand length of the dna, nor does it affect uptake of the dna by compentent s. pneumoniae cells in dnase i-resistant form. following uptake, however, dna previously exposed to the factor loses over 90% of its biological activity. reaction of heterospecific dna with the f ...	1978	26019
fate of heterospecific transforming dna bound to streptococcus sanguis.	the fate of 3h-labeled str-r fus-s dna from streptococcus pneumoniae, bound after a 1-min uptake to 14c-labeled str-s fus-r s. sanguis recipients, was followed by techniques previously developed for analyzing the fate of homospecific dna. heterospecific s. pneumoniae dna was bound and formed complexes with recipient protein in a manner similar to that of homospecific dna but transformed relatively poorly. the rate at which complexed heterospecific dna becomes physically associated with recipient ...	1978	25262
the microbiology and biochemistry of plaque, saliva, and drinking water from two communities with contrasting levels of caries in colombia, s.a.		1977	24649
attachment of bacteroides melaninogenicus subsp. asaccharolyticus to oral surfaces and its possible role in colonization of the mouth and of periodontal pockets.	this investigation examined the ability of cells of bacteroides melaninogenicus subsp. asaccharolyticus 381 to adhere to surfaces that might be important for its initial colonization of the mouth and its subsequent colonization in periodontal pockets. of 48 asaccharolytic strains of b. melaninogenicus, 47 agglutinated human erythrocytes, whereas none of 20 fermentative strains, which included reference cultures of the subspecies intermedius and melaninogenicus, were active. electron microscopy i ...	1978	24002
effect of ph and counter ions on the zeta-potential of oral streptococci.		1977	23746
enamel microhardness and fluoride uptake underneath fermenting and non-fermenting artificial plaque.	washed cells of streptococcus sanguis were used to form artificial plaque on the surface of bovine enamel and incubated underneath buffer solutions, initial ph 6, for 36 h at 37 degrees c. the decrease in the microhardness of the enamel surface under fermenting "plaque" could be prevented with fluoride. enamel under a fermenting "plaque" took up significantly more (p less than 0.0u) fluoride than enamel under a non-fermenting "plaque" (initial f- in buffer: 10 parts/10(6)). the artificial plaque ...	1977	22924
acid production from lycasin, maltitol, sorbitol and xylitol by oral streptococci and lactobacilli.	the acid production from maltitol was compared with the acid production from hydrogenated starch hydrolysate (lycasin), sorbitol and xylitol by a number of oral strains and reference strains of streptococcus mutans, s. sanguis, s. salivarius, s. mitior, s. milleri, s. faecalis, s. faecium, s. avium, lactobacillus casei and l. salivarius. the polyols were added to a final concentration of 1.0% to two different basal media. incubation was performed at 37 degrees c for 7 days after which the ph was ...	1977	21508
secretion of lipids induced by inhibition of peptidoglycan synthesis in streptococci.	inhibition of peptidoglycan synthesis causes an immediate and massive secretion of both newly synthesized and "old" lipids from several species of bacteria, including streptococci, staphylococcus epidermidis, and bacillus subtilis. lipid secretion occurs in the absence of detectable bacterial lysis. this novel phenomenon was examined in more detail in three strains of streptococci: s. sanguis (group h), s. pyogenes (group a), and s. pneumoniae. the secretion of lipids is specifically induced by ...	1977	21168
plaque formation by streptococci in an artificial mouth and factors influencing colonization.		1977	18435
characterization of group h streptococcal temperate bacteriophage phi 227.	phi 227, a temperate phage from a group h streptococcus (streptococcus sanguis), was propagated vegetatively in group h strain wicky 4-eryr, and its characteristics were determined. a procedure dependent on multiplicity of infection, incubation time, and treatment of crude lysates with diatomaceous earth was found to optimize phage yield, resulting in titers of 1 x 10(10) to 2 x 10(10) pfu/ml. without prior treatment with diatomaceous earth, subsequent purification procedures (methanol, ammonium ...	1977	15133
glucosyltransferase production by streptococcus sanguis 804 (nctc 10904).	streptococcus sanguis 804 (nctc 10904) was grown ih batch culture at constant ph. and the glucosyltransferase activity of the supernatant was assayed over a 40-h growth period. the optimum ph for enzyme production was 7.0 to 7.2. during growth of the culture, three reproducible phases of enzyme activity were observed. the polysaccharides synthesized during each of these phases were characterized as dextran-like glucans by analysis of acid hydrolysates, gas-liquid chromatography, and a specific a ...	1977	13040
lactate formation at various ph levels by the wild strain of streptococcus mutans pk 1, its variant, and s sanguis.		1976	12197
purification and some properties of free and cell-associated dextransucrase from streptococcus sanguis.	dextransucrase of streptococcus sanguis occurred in cell-free and cell-associated forms. cell-free dextransucrase was purified by four successive chromatographies on bio-gel p 60, deae-cellulose, and bio-gel p 200 from the culture supernatant. the purification of cell-associated dextransucrase was made from the pellet of streptococcus sanguis culture. bacterial pellet was extracted with 1 m phosphate buffer (ph 6.0) and chromatographied by using an immunosorbent column. the two enzymes gave sing ...	1976	11837
autolysis in strains of viridans streptococci.	seven strains of viridans streptococci of the species streptococcus sanguis, s. mutans and s. mitis were investigated for autolysis. the effect of ph, salt concentration and temperature on the autolytic process was studied in na2hpo4/nah2po4 buffer. whole cells and walls of all strains autolysed most rapidly at ph values above 7. autolysis of whole cells of s. sanguis and one strain of s. mitis (atcc15909) was maximal in 0-05 to 0-2 m buffer, while the two s. mutans strains and s. mitis atcc1591 ...	1976	10349
ph changes during culture of human dental plaque streptococci on mitis-salivarius agar.		1976	8030
ph and eh in single and mixed culture bacterial plaque in an artificial mouth.		1976	5393
effect of ph on competence development and deoxyribonucleic acid uptake in streptococcus sanguis (wicky).	streptococcus sanguis (wicky) cells, strain we4, developed little or no competence and failed to autolyze in permissive conditions when treated with competence factor (cf) below ph 7.0. this lack of activity was directly correlated with the inability of the cells to bind or take up cf at ph values of 5.5, 6.0, and 6.5. on the other hand, competent cells bound deoxyribonucleic acid molecules maximally below ph 7.0 and transformed maximally at ph 6.5. deoxyribonucleic acid was optimally bound to c ...	1976	4422
genetic hybridization at the unlinked thy and str loci of streptococcus.	the sanguis and pneumoniae species of streptococcus were used as recipients in transformations from str+ to str-r and from thy- to thy+. the str-r mutations in the two species had been previously shown to be allelic. homology of the thy- mutations in the two species was demonstrated in the similar phenotypic properties they conferred (death in the absence of thymidine, lack of thymidylate synthetase). the str and thy loci are unlinked in each species.--- when the two species are transformed by b ...	1975	1325
isolation and purification of flavobacterium alpha-1,3-glucanase-hydrolyzing, insoluble, sticky glucan of streptococcus mutans.	studies were made on the physical and chemical properties of polysaccharides synthesized by cell-free extracts of streptococcus mutans, streptococcus sanguis, and streptococcus sp. and their susceptibilities to dextranases. among the polysaccharides examined, insoluble glucans were rather resistant to available dextranase preparations, and the insoluble, sticky glucan produced by s. mutans omz 176, which could be important in formation of dental plaques, was the most resistant. by enrichment cul ...	1975	370