Biomaterial Database

Identification of cell wall antigens associated with a large conjugative plasmid encoding phage resistance and lactose fermentation ability in lactic streptococci. 1988

G M Dunny, and D A Krug, and C L Pan, and R A Ledford

Department of Microbiology, Immunology and Parasitology, Cornell-University, Ithaca, NY 14853.

In order to begin to analyze the gene products encoded by phage resistance plasmids in lactic streptococci, we identified phage-resistance plasmids by screening resistant strains from commercial starter cultures for the ability to carry out unselected cotransfer, by conjugation, of phage resistance with lactose fermentation ability (lac+). In this fashion, we identified a large (90 kilobases) plasmid, pCLP51R, that encodes the lac+ marker, resistance to a lytic phage called LP10G (1pr+), high-frequency conjugal donor ability (hft+), and clumpy growth of host bacteria in broth culture (clu+). The mechanism of resistance conferred by this plasmid appears to involve interference with a step in the phage replication cycle that occurs after the initial attachment of the phage. Polyacrylamide gel electrophoresis of cell surface extracts of isogenic strains, carrying or lacking pCLP51R, combined with immunoblotting analysis, showed that there were several plasmid-related differences in the banding pattern of low molecular weight proteins and that the plasmid resulted in production of several unique antigenic polypeptides in the size range of 15-30 kd, as well as modification of chromosomally encoded antigens to different molecular weight forms.

UI	MeSH Term	Description	Entries
D007785	Lactose	A disaccharide of GLUCOSE and GALACTOSE in human and cow milk. It is used in pharmacy for tablets, in medicine as a nutrient, and in industry.	Anhydrous Lactose,Lactose, Anhydrous
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
D002473	Cell Wall	The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.	Cell Walls,Wall, Cell,Walls, Cell
D003227	Conjugation, Genetic	A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.	Bacterial Conjugation,Conjugation, Bacterial,Genetic Conjugation
D005285	Fermentation	Anaerobic degradation of GLUCOSE or other organic nutrients to gain energy in the form of ATP. End products vary depending on organisms, substrates, and enzymatic pathways. Common fermentation products include ETHANOL and LACTIC ACID.	Fermentations
D000942	Antigens, Bacterial	Substances elaborated by bacteria that have antigenic activity.	Bacterial Antigen,Bacterial Antigens,Antigen, Bacterial
D000954	Antigens, Surface	Antigens on surfaces of cells, including infectious or foreign cells or viruses. They are usually protein-containing groups on cell membranes or walls and may be isolated.	Cell Surface Antigens,Surface Antigens,Surface Markers, Immunological,Cell Surface Antigen,Immunologic Surface Markers,Markers, Immunological Surface,Surface Antigen,Surface Markers, Immunologic,Antigen, Cell Surface,Antigen, Surface,Antigens, Cell Surface,Immunological Surface Markers,Markers, Immunologic Surface,Surface Antigen, Cell,Surface Antigens, Cell
D001435	Bacteriophages	Viruses whose hosts are bacterial cells.	Phages,Bacteriophage,Phage
D013291	Streptococcus	A genus of gram-positive, coccoid bacteria whose organisms occur in pairs or chains. No endospores are produced. Many species exist as commensals or parasites on man or animals with some being highly pathogenic. A few species are saprophytes and occur in the natural environment.