Hot saline extracts of Streptococcus mutans have been shown to contain antigenic substances which occasionally react nonspecifically with some antisera against whole cells of various serological groups and types of streptococci. Chromatography of the extract of S. mutans strain MT703 (serotype e) on a diethylaminoethyl-Sephadex A-25 column gave two principal antigens. One antigen was eluted without adsorption to the resin and was identified as the serotype-specific polysaccharide. The other antigen, which contained a large quantity of phosphorus, was adsorbed to and released from the resin by gradient elution. It was reactive against the antisera specific for polyglycerophosphate (PGP) from group A Streptococcus pyogenes and/or S. mutans strain Ingbritt (type c). The PGP antigen was further purified by gel filtration with Sephadex G-75. Two peaks, PGP-1 and PGP-2, were obtained. Each possessed the same antigenic specificity to anti-PGP serum as shown by immunodiffusion. Chemical analyses revealed that the molar ratio of phosphorus to glycerol in both was about 1:1, although the protein content between the two was significantly different. PGP antigen was found to be widely distributed in hot saline extracts from various gram-positive bacteria, with a few exceptions. However, all gramnegative bacteria examined were free of PGP. The PGP in the hot saline extracts of various gram-positive bacteria possessed an essentially identical antigenic specificity. The addition of diethylaminoethyl-Sephadex A-25 resin to hot saline extracts successfully removed the cross-reacting PGP antigen. After adsorption of the extract from S. mutans, the supernatant contained only type-specific polysaccharide antigen, except type b, in which both type b-specific polysaccharide and PGP antigens were adsorbed with the resin. This simple procedure should be useful for the removal of the PGP-type teichoic acid from antigen extracts of bacteria that contain uncharged polysaccharides. Umemoto (New York State University School of Dentistry at Buffalo, Buffalo), B. Guggenheim 903 on July 15, 2020 by guest http://iai.asm.org/ Downloaded from
Lyophilized and heat-treated cells from the seven serotypes of Streptococcus mutans were examined for their ability to bind added insoluble-product glucosyltransferase (GTase) and to synthesize cell-associated glucan from ["C]sucrose. Lyophilized cells of serotypes a and g did not synthesize any more additional glucan than did the controls after exposure to GTase. These cells, however, synthesized fourto eightfold-greater quantities of glucan than did the cells of the remaining serotypes. Lyophilized cells of serotypes b, c, d, e, and f synthesized
Regulation of the diphtheria toxin promoter by iron was studied in Escherichia coli by using a galK transcriptional fusion. A fragment of the toxin (tox) operon containing the regulatory region was cloned from corynephage , into a galK transcription vector such that expression of galK activity was controlled by the tox promoter. When E. coli N100 (a galK mutant) harboring this tox-galK fusion plasmid was grown in Luria broth, the specific activity of galactokinase remained constant throughout the exponential phase of growth. When bacteria were shifted from such high-iron medium into low-iron Luria broth, the specific activity of galactokinase increased rapidly, but induction of galactokinase was prevented by the addition of iton to the medium. Measurement of tox-specific mRNA by dot blot hybridization showed that this regulation occurred at the level of transcription. When the plasmid containing the tox-galK fusion was introduced into a fur mutant of E. coli, expression of galK was maximal in both high-iron and low-iron media; but repressibility of galK by iron in this strain was restored by complementation with the fur' allele. The tox promoter has significant homology with the consensus sequence for other iron-regulated promoters of E. coli that are controlled by fur. These data indicate that the product of thefur gene can function in E. coli as an iron-dependent repressor for the tox promoter from corynephage P. prepared, stored at 4°C, and used throughout the study. Plastic pipettes and sterile disposable plastic flasks were used to prepare cultures. Cells of C. diphtheriae were grown at 34°C in PTY medium, which contains 10 g of yeast extract, 10 g of Casamino Acids (Difco Laboratories, Detroit, Mich.), 0.1 g of L-tryptophan, 0.5 ml of 0.18% calcium pantothenate, 2 ml of solution 11 (32), and 1 ml of solution III (32) per liter. The pH was adjusted to 7.2 with 10 N potassium hydroxide. PTY medium was supplemented with 0.1 volume of 20% maltose-0.3% calcium chloride before use. Growth of corynephage , and preparation of phage DNA. An overnight culture of C. diphtheriae C7 was diluted fivefold with fresh medium and grown at 34°C with shaking until the A590 was approximately 2. The culture was infected with phage P at a multiplicity of 1, and A5%0 was monitored. At the first indication of cell lysis, sodium citrate was added to a final concentration of 30 mM. After incubation for an 2430
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.