Biomaterial Database

Mutants of Escherichia coli O9:K30 with altered synthesis and expression of the capsular K30 antigen. 1989

C Whitfield, and G Schoenhals, and L Graham

Department of Microbiology, College of Biological Sciences, University of Guelph, Ontario, Canada.

Escherichia coli K30 produces a thermostable group I capsular polysaccharide. Two classes of mutants were isolated with defects in the synthesis or expression of capsule. The most common mutant phenotype was acapsular (K-), with no K-antigen synthesized. A second class of mutants, termed Ki or intermediate forms, produced colonies which were indistinguishable from those of acapsular forms yet K-antigenicity was expressed. Previous studies had demonstrated that E. coli strains that produce K30 antigen synthesize a lipopolysaccharide (LPS) fraction that is recognised by monoclonal antibodies against the K30 antigen. Synthesis of this LPS fraction was not affected in Ki forms. The results of morphological examination, LPS analysis and phage sensitivity studies are consistent with the interpretation that the defect in Ki strains results from an inability to polymerize the K30 antigen. Using plasmid pULB113 (RP4::mini-Mu), mutations resulting in both K- and Ki phenotypes were localized near the his region of the chromosome.

UI	MeSH Term	Description	Entries
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D010641	Phenotype	The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.	Phenotypes
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
D011135	Polysaccharides, Bacterial	Polysaccharides found in bacteria and in capsules thereof.	Bacterial Polysaccharides
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D002874	Chromosome Mapping	Any method used for determining the location of and relative distances between genes on a chromosome.	Gene Mapping,Linkage Mapping,Genome Mapping,Chromosome Mappings,Gene Mappings,Genome Mappings,Linkage Mappings,Mapping, Chromosome,Mapping, Gene,Mapping, Genome,Mapping, Linkage,Mappings, Chromosome,Mappings, Gene,Mappings, Genome,Mappings, Linkage
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
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