Biomaterial Database

Resistance of a Tn4351-generated polysaccharide mutant of Porphyromonas gingivalis to polymorphonuclear leukocyte killing. 1995

C A Genco, and R E Schifferle, and T Njoroge, and R Y Forng, and C W Cutler

Department of Microbiology and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310.

In this study, we describe the development of an efficient transpositional mutagenesis system for Porphyromonas gingivalis using the Bacteroides fragilis transposon Tn4351. Using this system, we have isolated and characterized a Tn4351-generated mutant of P. gingivalis A7436, designated MSM-1, which exhibits enhanced resistance to polymorphonuclear leukocyte (PMN) phagocytosis and killing. P. gingivalis MSM-1 was initially selected based on its colony morphology; MSM-1 appeared as a mucoid, beige-pigmented colony. Analysis of P. gingivalis MSM-1 by electron microscopy and staining with ruthenium red revealed the presence of a thick ruthenium red-staining layer that was twice the thickness of this layer observed in the parent strain. P. gingivalis MSM-1 was found to be more hydrophilic than strain A7436 by hydrocarbon partitioning. Analysis of phenol-water extracts prepared from P. gingivalis A7436 and MSM-1 by Western (immunoblot) analysis and immunodiffusion with hyperimmune sera raised against A7436 and MSM-1 revealed the loss of a high-molecular-weight anionic polysaccharide component in extracts prepared from MSM-1. P. gingivalis MSM-1 was also found to be more resistant to PMN phagocytosis and intracellular killing than the parent strain, as assessed in a fluorochrome phagocytosis microassay. These differences were statistically significant (P < 0.05) when comparing PMN phagocytosis in nonimmune serum and intracellular killing in nonimmune and immune sera. P. gingivalis MSM-1 was also more resistant to killing by crude granule extracts from PMNs than was P. gingivalis A7436. These results indicate that the increased evasion of PMN phagocytosis and killing exhibited by P. gingivalis MSM-1 may result from alterations in polysaccharide-containing antigens.

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
D009504	Neutrophils	Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes.	LE Cells,Leukocytes, Polymorphonuclear,Polymorphonuclear Leukocytes,Polymorphonuclear Neutrophils,Neutrophil Band Cells,Band Cell, Neutrophil,Cell, LE,LE Cell,Leukocyte, Polymorphonuclear,Neutrophil,Neutrophil Band Cell,Neutrophil, Polymorphonuclear,Polymorphonuclear Leukocyte,Polymorphonuclear Neutrophil
D010587	Phagocytosis	The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).	Phagocytoses
D011135	Polysaccharides, Bacterial	Polysaccharides found in bacteria and in capsules thereof.	Bacterial Polysaccharides
D003602	Cytotoxicity, Immunologic	The phenomenon of target cell destruction by immunologically active effector cells. It may be brought about directly by sensitized T-lymphocytes or by lymphoid or myeloid "killer" cells, or it may be mediated by cytotoxic antibody, cytotoxic factor released by lymphoid cells, or complement.	Tumoricidal Activity, Immunologic,Immunologic Cytotoxicity,Immunologic Tumoricidal Activities,Immunologic Tumoricidal Activity,Tumoricidal Activities, Immunologic
D004251	DNA Transposable Elements	Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.	DNA Insertion Elements,DNA Transposons,IS Elements,Insertion Sequence Elements,Tn Elements,Transposable Elements,Elements, Insertion Sequence,Sequence Elements, Insertion,DNA Insertion Element,DNA Transposable Element,DNA Transposon,Element, DNA Insertion,Element, DNA Transposable,Element, IS,Element, Insertion Sequence,Element, Tn,Element, Transposable,Elements, DNA Insertion,Elements, DNA Transposable,Elements, IS,Elements, Tn,Elements, Transposable,IS Element,Insertion Element, DNA,Insertion Elements, DNA,Insertion Sequence Element,Sequence Element, Insertion,Tn Element,Transposable Element,Transposable Element, DNA,Transposable Elements, DNA,Transposon, DNA,Transposons, DNA
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000942	Antigens, Bacterial	Substances elaborated by bacteria that have antigenic activity.	Bacterial Antigen,Bacterial Antigens,Antigen, Bacterial
D012995	Solubility	The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Solubilities