Lipopolysaccharides of group F, a new group of vibrios

Structural studies on the neutral polysaccharide of Bacillus subtilis AHU 1219 cell walls

A neutral and an acidic polysaccharide with molecular masses of about 22 kDa and 45 kDa, respectively, were isolated from the N-acetylated cell walls of Bacillus subtilis AHU 1219 by heating at pH 2.5, followed by separation of the water-soluble product by ion-exchange chromatography and gel chromatography. The neutral polysaccharide, accounting for 40% of the mass of the cell walls, contained glucose, N-acetylglucosamine, N-acetylgalactosamine and N-acetylmannosamine in a molar ratio of 1:2:1:1. The minor, acidic polysaccharide contained glucuronic acid, glucose, galactose, L-serine and L-threonine in an approximate molar ratio of 1:1:1:0.5:0.5. Lysozyme digestion of the N-acetylated cell walls gave a polymer containing the neutral polysaccharide and glycopeptide components and another polymer which contained the acidic polysaccharide components together with small proportions of the neutral polysaccharide and glycopeptide components. Thus, the neutral and acidic polysaccharide chains seem to be attached to peptidoglycan through acid-labile linkages in the cell walls of this strain. Structural analysis of the neutral-polysaccharide preparation, involving 1H-NMR and 13C-NMR measurement, methylation and Smith degradation, led to the most likely structure, ----6)[Glc(beta 1----3)]GalNAc(alpha 1----4)-[GlcNAc(beta 1----3)]ManNAc(beta 1----4)GlcNAc(beta 1----, for the repeating units of this polysaccharide.

Thyrotropin and norepinephrine stimulate the metabolism of phosphoinositides in FRTL-5 thyroid cells

Hormone-induced changes in phospholipid metabolism were examined in a functioning rat thyroid cell line (FRTL-5). Stimulation of FRTL-5 cells, prelabeled with 32P, with TSH or NE resulted in a rapid decrease in the radioactivity of both phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidylinositol 4-monophosphate (PIP). The effects of TSH on phospholipid metabolism and calcium mobilization are independent of those on adenylate cyclase. This suggests that the TSH receptor may be unique in that it activates enzyme cascades involved in cAMP production and Ca2+ mobilization.

Occurrence of uronic acid in lipopolysaccharides of Vibrionaceae

The occurrence of uronic acid as a sugar constituent of lipopolysaccharides (LPS) in Vibrionaceae was demonstrated for the first time. More than 100 strains were examined. Of five genera constituting Vibrionaceae, i.e., Vibrio, Aeromonas, Plesiomonas, Photobacterium, and Lucibacterium, the latter three contained uronic acid in LPS of all of their constituting members examined, while it was totally lacking in Aeromonas LPS so far tested. Only the members of genus Vibrio were found to be divided into uronic acid-containing and -lacking groups; V. parahaemolyticus, V. alginolyticus, V. fisheri, V. costicola, Beneckea ('Vibrio'), and V. fluvialis belonged to the former, while all four biotypes of V. cholerae regardless of their serotypes, V. vulnificus and V. anguillarum, belonged to the latter group. The uronic acid content of V. parahaemolyticus O1 to O12 LPS ranged from 1.6 to 4.2%. The uronic acid residue released from V. parahaemolyticus O1, O4, O10, and O12 LPS by heating in 5% acetic acid at 100 C for 2 hr was identified as galacturonic acid; in particular, that from O12 LPS was characterized as D-galacturonic acid.

Isolation of an unusual 'lipid A' type glycolipid from Pseudomonas paucimobilis

A new glycolipid was isolated from defatted cells of Pseudomonas paucimobilis IAM 12576, and called 'bound lipid'. The 'bound lipid' could not be extracted by hot phenol extraction, but could be extracted with hot chloroform/methanol after hydrolysis with 5% trichloroacetic acid. The 'bound lipid' was purified by thin-layer chromatography on silica gel plates using the solvent mixture CHCl3/CH3OH/CH3COOOH/ H2O (25:15:4:2, v/v). It consisted of glucosamine, 2-hydroxy myristic acid, galactose, mannose and uronic acid with ratios of 1.0:0.75:0.77:0.44:1.5, respectively, and other fatty acids besides 2-hydroxy myristic acid were not detected in the 'bound lipid'. 2-Hydroxy myristic acid was probably bound to glucosamine residues by amide linkage, because mild alkali treatment did not liberate the fatty acid. From these results, we discussed the possibility that the 'bound lipid' was some kind of lipid A of this bacteria.

Vibrio parahaemolyticus and related halophilic Vibrios

Approximately 30 years have elapsed since Dr. Fujino's original discovery that Vibrio parahaemolyticus (then termed Pasteurella parahemolytica) was the cause of "summer diarrhea" in Japan. Since that finding, V. parahaemolyticus has been established as a cause of gastroenteritis in numbers and places approaching global proportions. It has been isolated in marine and estuarine areas almost worldwide and despite its halophilic nature, V. parahaemolyticus has been isolated from saline-free waters. The relationship of this organism to the environment reveals a close association with other marine organisms especially copepods on which the Vibrios depend for survival in winter months and growth in summer months. There is a uniquely provocative disparity between human strains of V. parahaemolyticus which are Kanagawa phenomenon (KP) positive and the environmental strains which to a large extent are KP negative, the significance being that pathogenicity is measured according to the Kanagawa phenomenon (hemolytic activity) reaction. The hemolysin of the pathogenic strains is a thermostable, cardiotoxic protein, which thus far has not been implicated in the mechanism(s) which causes human gastroenteritis. The interest in this organism has been widened in recent years by the finding that similar organisms, V. alginolyticus, lactose positive vibrios and group F vibrios also cause serious disease in humans.

Distribution of mannosamine and mannosaminuronic acid among cell walls of Bacillus species

The distribution of mannosamine, mannosaminuronic acid, and the enzymes responsible for the formation of these saccharides was studied in nine species (18 strains) of Bacillus. Whereas UDP-N-acetylglucosamine 2-epimerase activity was detected in all of the strains examined, UDP-N-acetylmannosamine dehydrogenase, as well as the activity incorporating N-acetylmannosaminuronic acid residues from UDP-N-acetylmannosaminuronic acid into polymer, was found only in four strains of B. megaterium and one strain each of B. subtilis and B. polymyxa. The cell walls prepared from the six above-named strains were shown to contain mannosaminuronic acid in amounts of 135 to 245 nmol/mg. In contrast, mannosamine had a wide distribution. The cell walls from two strains of B. cereus and one strain each of B. circulans, B. polymyxa, B. sphaericus, and B. cereus subsp. mycoides contained mannosamine in amounts of 370 to 470 nmol/mg. In addition, the cell walls from five strains of B. subtilis, two strains of B. megaterium, and one strain each of B. cereus. B. coagulans, and B. licheniformis also contained this amino sugar in amounts as small as 10 to 35 nmol/mg. On the basis of analytical data, it is suggested that the mannosamine present in small amounts may be a common constituent of linkage units between peptidoglycan and other cell wall components such as glycerol teichoic acid.