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T Hofstad

Publications and source records attributed to T Hofstad.

At least 73 records · Page 4Linked to original sources
PubMed1981

Precipitating carbohydrate antigens of Bacteroides fragilis NCTC 9343.

An antigen fraction isolated by various forms of chromatography from phenol/water extracts of Bacteroides fragilis NCTC 9343 was devoid of phosphorus, fatty acids and amino acids. Rhamnose, fucose, galactose, glucose and a neutral sugar tentatively identified as arabinose were present at molar ratios of 1:1:1.2:9.0.9:0.7. The fraction contained an unidentified reducing and ninhydrin positive substance and trace amounts of glucosamine and galactosamine. The antigen fraction produced three immunoelectrophoretic bands against NCTC 9343 antiserum, and reacted in complement fixation tests.

Antigens, Bacterial↗
PubMed1981

The effect of hyperbaric oxygenation on experimental Bacteroides fragilis infection in the rat liver.

An experimental intra-abdominal model for producing Bacteroides fragilis abscesses in the rat liver was used to evaluate the therapeutic effect of hyperbaric oxygenation (HO) at 3 ATA (atmospheres absolute). Two different experiments were performed. In the first experiment one half of the animals were inoculated with B. fragilis, and the other half were sham-operated. Whether the inoculated or sham-operated animals were given single or repeated HO treatment at 3 ATA for 90 min, the bacteriological pattern was about the same. In the second experiment all the animals were inoculated with B. fragilis; half of the animals were given HO at 3 ATA for 90 min as single or repeated treatments, and the other half acted as controls receiving no HO. Even if the HO treatment was given every day during 21 days, B. fragilis could be recovered in all inoculated animals 22 days after inoculation.

Animals↗
PubMed1980

Lipopolysacharides from anaerobic gram-negative rods.

The chemical composition and antigenic specificity of the cell wall lipopolysaccharides of the two main groups of Bacteroidaceae, Fusobacterium and Bacteroides species, are reviewed. Cell wall lipopolysaccharides from Fusobacterium species contain 2-keto-3-deoxy-octonate and heptose, but lipopolysaccharides isolated from Bacteroides species do not.

Bacteroidaceae↗
PubMed1980

Evaluation of the API ZYM system for identification of Bacteroides and Fusobacterium species.

The API ZYM patterns of 97 Bacteroides and 25 Fusobacterium strains were examined. The system discriminated between B. asaccharolyticus, B. melaninogenicus ss. melaninogenicus, and B. melaninogenicus ss. melaninogenicus, but not between other Bacteroides species or between species of Fusobacterium. The results provided new information on the enzymatic activity of these groups of bacteria.

Alkaline Phosphatase↗
PubMed1980

Fatty acids and neutral sugars present in lipopolysaccharides isolated from Fusobacterium species.

Lipopolysaccharides (LPS) extracted from cells of Fusobacterium necrophorum, F. mortiferum, F. Gonidiaformans. varium and single strains of F. naviforme and F. russi were analysed for sugars and fatty acids. All preparations contained a monosaccharide tentatively identified as L-glycero-D-mannoheptose, but showed variation with respect to the presence of glucose, galactose, rhamnose and another heptose isomer, tentatively identified as L-glycero-D-mannoheptose. L-glycero-D-mannoheptose was a monosaccharide of great abundance in all LPS examined. 2-keto-3-deoxy-octonate and glucosamine were present in all LPS preparations. The fatty acids present were 3-hydroxy-tetradecanoic acid as the main component, and n-tetradecanoic acid. Some LPS contained n-hexadecanoic acid. All the strains of F. nucleatum contained 3-hydroxy-hexadecanoic acid as a group-specific LPS constituent.

Calorimetry↗
PubMed1980

Nature, type of linkage, quantity, and absolute configuration of (3-hydroxy) fatty acids in lipopolysaccharides from Bacteroides fragilis NCTC 9343 and related strains.

The main fatty acids present in lipopolysaccharides from Bacteroides fragilis NCTC 9343 were identified as 13-methyl-tetradecanoic, D-3-hydroxypentadecanoic, D-3-hydroxyhexadecanoic, D-3-hydroxy-15-methyl-hexadecanoic, and D-3-hydroxyheptadecanoic acids. Of these, 13-methyl-tetradecanoic acid is exclusively ester bound, and 3-hydroxy-15-methyl-hexadecanoic acid is exclusively involved in amide linkage. The other 3-hydroxy fatty acids are both ester and amide bound. All 3-hydroxy fatty acids possess the D configuration, and the 3-hydroxyl group of ester-linked 3-hydroxy fatty acids is not substituted. Lipopolysaccharides of related Bacteroides species (B. thetaiotaomicron, B. ovatus, B. distasonis, and B. vulgatus) showed a fatty acid spectrum with both similar and distinct features compared to that of B. fragilis lipopolysaccharides.

Bacteroides↗
PubMed1979

Immunochemical studies of partially hydrolyzed lipopolysaccharide from Fusobacterium nucleatum Fev1.

Fusobacterium nucleatum Fev1 lipopolysaccharide was split by hydrolysis with 1% acetic acid into acid-soluble polysaccharide and lipid A. Gel filtration of the polysaccharide on Bio-Gel P-60 gave a high-molecular-weight fraction eluted with the void volume, and a fraction eluted at 2.4 x Vo. The high-molecular-weight fraction contained L-glycero-D-manno-heptose in relatively large amounts, glucose, glucosamine, an unknown amino compound and small amounts of (or no) D-glycero-D-manno-heptose. Phosphorus and 3-deoxy-D-manno-octulosonic acid were not detected. The other fraction contained L- and D-glycero-D-manno-heptose, glucose, glucosamine, 3-deoxy-d-manno-octulosonic acid and phosphorus. Further fractionation experiments and serological investigations indicated that the high-molecular-weight fraction carried the O-antigenic side chains, whereas the material eluted from Bio-Gel P-60 at 2.4 x Vo represented the core oligosaccharide.

Antigens, Bacterial↗
PubMed1979

O-antigenic cross-reactivity in Fusobacterium nucleatum.

Lipopolysaccharides (LPS) of the same chemotype isolated from seven strains of Fusobacterium nucleatum were examined by indirect haemagglutination and inhibition of haemagglutination in unabsorbed and absorbed antisera. Four common major antigenic specificities were detected, and two of the LPS examined contained antigenic specificities not shared with any of the other LPS. In addition, a few weak cross-reactions were observed, also with some LPS of other chemotypes.

Antibodies, Bacterial↗
PubMed1979

Demonstration of lanthionine as a natural constituent of the peptidoglycan of Fusobacterium nucleatum.

Peptidoglycan was purified from the oral bacterium Fusobacterium nucleatum strain Fev 1, using boiling sodium dodecyl sulfate and pronase. The composition of this peptidoglycan was found to be similar to that of other gram-negative bacteria, except that it lacked diaminopimelic acid. Lanthionine, the monosulfur analog of diaminopimelic acid, was identified as the diaminodicarboxylic acid of this peptidoglycan. It is assumed that lanthionine replaced diaminopimelic acid. Thus, the peptidoglycan of F. nucleatum Fev 1 is one of the few known sources of naturally occurring lanthionine.

Alanine↗
PubMed1979

The influence of specific antibodies and cellular immunity in the induction of tolerance of chemotactic activity caused by Bacteroides fragilis lipopolysaccharide.

Exudate aspirated from wound chambers implanted subcutaneously on rabbits at different time intervals after local lipopolysaccharide (LPS) injection, showed a peak of chemotactic mediator concentration in vitro about two hours before the peak of polymorphonuclear lekocytes accumulated in vivo was demonstrated. Injection of LPS locally into the wound chambers three days after the first injection of LPS showed a reduced number of PMNs accumulated in the exudate. Antibodies to the LPS preparation were demonstrated in the exudate and serum by indirect haemagglutination of sheep erythrocytes before the second LPS injection. This antibody titre increased up to two weeks after the first LPS injection, and was slightly higher in the serum than in the exudate. Also, a migration inhibition factor (MIF) activity was demonstrated in the exudates formed. This MIF activity of the exudates increased after the second LPS injection. The increased titre of specific antibody may indicate an accelerated clearance of LPS, and the MIF activity may indicate a reduced response of PMNs to chemotactic mediators. However, the involvement of other biological mechanisms contributing to the decreased response, cannot be excluded.

Animals↗
PubMed1979

Experimental Bacteroides fragilis abscess in the rat liver.

Liver abscess was induced in rats by injecting a culture of B. fragilis ss. fragilis (approx. 5X10(6) cells) into devascularized liver tissue. Mixed infection with B. fragilis and aerobes occurred in all animals subjected to repeated laparotomies for bacteriological sampling (4, 7, 14 and 28 days after inoculation). In animals sampled only at 8 or at 42 days after injection, B. fragilis was isolated in pure culture from the majority of animals. The size of abscesses containing B. fragilis in pure culture decreased markedly between 8 and 42 days after inoculation. In inoculated animals and in sham-operated animals with secondary infection histological examination revealed an abscess containing necrotic liver tissue and numerous granulocytes. In sham-operated animals with no bacterial growth the histological examination microscopy revealed a liver infarct with incipient organization and no accumulation of granulocytes.

Animals↗
PubMed1979

Endotoxins of anaerobic gram-negative rods.

Endotoxic lipopolysaccharides (LPS) isolated from Fusobacterium are similar to those of Salmonella with respect to chemical composition, O-antigenic specificity and endotoxic activity. Bacteroides LPS are highly atypical with respect to the chemical composition, and their endotoxic activity is low. O-Antigenic specificity is present. B. fragilis LPS is chemotactic for polymorphonuclear leukocytes in vitro and in vivo. The chemotactic activity is brought about by activation of the alternative complement pathway.

Animals↗
PubMed1978

Chemotypes of Fusobacterium nucleatum lipopolysaccharides.

Lipopolysaccharides (LPS) were isolated from 20 strains of Fusobacterium nucleatum and examined by paper chromatography, gas liquid chromatography and colorimetric methods for the presence of neutral sugars, amino sugars and 2-keto-3-dexoxy-octonate (KDO). The LPS had in common glucosamine, L-glycero-D-manno-heptose, glucose and KDO. The KDO content was low. Galatose, rhamnose and D-glycero-D-manno-heptose were found in some strains. Based on the sugar composition of the LPS, the F. nucleatum strains could be classified into six chemotypes.

Chromatography, Gas↗
PubMed1978

Chemotypes of Veillonella lipopolysaccharides.

Lipopolysaccharides (LPS) were isolated by phenol-water extraction from 34 strains of Veillonella, and examined by paper chromatography and colorimetric methods for the presence of neutral sugars, amino sugars and 2-keto-3-deoxy-octonate (KDO). Several preparations were also examined for neutral sugars by gas liquid chromatography. The LPS had in common glucosamine, galactosamine, L-glycero-D-manno-heptose glucose and KDO. Most LPS contained galactose, and a few rhamnose. D-glycero-D-manno-heptose was found in LPS from one of the strains. Based on the sugar composition of the LPS, the Veillonella strains could be classified into four chemotypes.

Chromatography, Gas↗