ABSTRACT
AIM: To investigate the adhesion determinants of Lactobacillus plantarum Lp6, a dairy isolate. METHODS AND RESULTS: Small intestinal mucus extracted from rats was used as a substrate for adhesion. Adhesion determinants were studied by physical, chemical and enzymatic pretreatments of the bacteria, and adhesion inhibition assay. The mannose-specific adhesins were explored by studying the effect of d-mannose on adhesion and the yeast-agglutinating ability of the bacteria. It was found that adhesion decreased after bacteria were treated with sodium metaperiodate, protease K, trypsin, lithium chloride and trichloroacetic acid. However, adhesion did not decrease after trypsin-treated bacteria were incubated with cell surface protein extract. Cell surface bound exopolysaccharides were found to inhibit the adhesion. D-mannose inhibited the adhesion in a dose-dependent manner. The bacteria could significantly agglutinate yeast and lost this ability after protease K treatment. CONCLUSIONS: Adhesion was mainly mediated by the mannose specific adhesins, which might be proteins that reversibly bind to the cell surface components. Cell surface-bound exopolysaccharides were also involved in adhesion. SIGNIFICANCE AND IMPACT OF THE STUDY: The mannose-specific adhesion of Lact. plantarum Lp6 to rat mucus might be important for competing with pathogens-binding sites in gut, which may be used to resist the colonization of the pathogens.
Subject(s)
Bacterial Adhesion/physiology , Intestinal Mucosa/microbiology , Intestine, Small/cytology , Lactobacillus plantarum/physiology , Mannose/metabolism , Adhesins, Bacterial/metabolism , Animals , Intestinal Mucosa/metabolism , Lactobacillus plantarum/cytology , RatsABSTRACT
In the present study, the lipoxygenase activity in polymorphonuclear (PMN) leukocytes of rats was characterized, and the change in lipoxygenase activity in peritoneal and peripheral PMN leukocytes challenged by caseinate was investigated. Peritoneal PMN leukocytes produced 5-HETE and LTB4 as the major 5-lipoxygenase metabolites from arachidonic acid. The 5-lipoxygenase activity was calcium dependent. Caseinate treatment in rats significantly stimulated the 5-lipoxygenase activity in peripheral and peritoneal PMN leukocytes. Although it also stimulated the cyclooxygenase metabolic pathway, the effect was not as evident as that on the 5-lipoxygenase pathway. Since LTB4 is a potent chemotactic factor for PMN leukocyte migration, the present results might explain the mechanism on the PMN leukocyte infiltration caused by caseinate treatment.
Subject(s)
Arachidonate 5-Lipoxygenase/metabolism , Arachidonate Lipoxygenases/metabolism , Caseins/pharmacology , Neutrophils/enzymology , Animals , Arachidonic Acid , Arachidonic Acids/metabolism , Calcium/pharmacology , Hydroxyeicosatetraenoic Acids/biosynthesis , Leukotriene B4/biosynthesis , Male , Neutrophils/drug effects , Peritoneal Cavity/cytology , Prostaglandin-Endoperoxide Synthases/metabolism , Rats , Rats, Inbred StrainsABSTRACT
12-Lipoxygenase activity in platelets of spontaneously hypertensive rats was investigated. Enzyme activity was measured in the absence and the presence of reduced glutathione. In both assay conditions, 12-lipoxygenase activity in platelets of spontaneously hypertensive rats was significantly higher than that in platelets of normotensive rats. Since 12-L-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE), a 12-lipoxygenase product of arachidonic acid in platelets, has been reported to be a potent chemoattractant for aortic smooth muscle cells, increase in biosynthesis of 12-HETE in platelets of spontaneously hypertensive rats might contribute to the explanation of pathogenesis of vascular disorder commonly found in hypertension patients.
