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T Hofstad

Publications and source records attributed to T Hofstad.

At least 55 records · Page 3Linked to original sources
PubMed1985

Antigenicity of lipopolysaccharides from Campylobacter jejuni and Campylobacter coli in passive haemagglutination tests and enzyme-linked immunosorbent assays.

Passive haemagglutination tests and ELISA were used to study the serological activity of homologous and heterologous rabbit antisera against LPS prepared from various strains of C. jejuni/coli. In both test systems the homologous antisera exhibited serological activity against LPS. The heterologous antisera showed some degree of intra- and inter- species cross-reactivity. The cross-reacting was most pronounced in the ELISA. Erythrocytes sensitized with untreated LPS gave higher antibody-titres than erythrocytes sensitized with alkali-treated LPS in the haemagglutination tests.

Campylobacter↗
PubMed1985

Adhesion of anaerobic gram-negative bacteria to mucosal surfaces.

Fusobacterium nucleatum and black-pigmented Bacteroides species adhere to red blood cells and crevicular epithelium. The attachment of the bacteroides, but not F. nucleatum, is associated with the presence of fimbriae-like structures on the bacterial surface. Such structures have been observed also in unencapsulated Bacteroides fragilis able to adhere to human red cells and cheek epithelium. Encapsulated B. fragilis adheres to porcine brush borders, but the number of adhering cells per brush border fragment is low.

Adhesiveness↗
PubMed1985

The classification and identification of the anaerobic gram-positive cocci.

The Approved Lists of Bacterial Names (1980) includes the following Peptococcus and Peptostreptococcus species pathogenic for man: Peptococcus magnus, P. prevotii, P. asaccharolyticus, Peptostreptococcus anaerobius, P. micros and P. productus. A presumptive identification of these species can be made on the basis of cellular morphology, susceptibility to novobiocin, characterization of metabolic end products, fermentation of glucose and lactose, and production of indol. Capnophilic and microaerophilic streptococci are characterized by their production of lactic acid from glucose.

Bacteriological Techniques↗
PubMed1984

Immune responses to anaerobic gram-negative bacteria in health and disease.

In the serum of healthy and sick persons antibodies to Bacteroidaceae and Veillonella have been detected. The antibody titres to these anaerobic bacteria are commonly low, in adults, however, higher than in children. High antibody titres could be found in patients suffering from Crohn's disease and in cancer patients. Immune responses to anaerobic bacteria occur in periodontal processes, too. These antibodies belong mainly to the IgM class of immunoglobulins. On the contrary, antibodies observed in patients with sepsis belong to the IgG class.

Antibodies, Bacterial↗
PubMed1984

Chemical studies of partially hydrolysed lipopolysaccharides from four strains of Campylobacter jejuni and two strains of Campylobacter coli.

Lipopolysaccharides (LPS) from four strains of Campylobacter jejuni and two strains of C. coli were partially hydrolysed with 1% acetic acid. Subsequent chloroform extraction led to the formation of a polysaccharide-containing aqueous layer, an interfacial material and a lipid A-containing chloroform layer. The polysaccharides contained the neutral sugars, amino sugars, 2-keto-3-deoxy-octonic acid, and part of the phosphorus present in the undegraded LPS. The lipid As were made up of glucosamine, phosphorus, ester- and amide-linked 3-hydroxytetradecanoic acid, and ester-linked n-tetradecanoic and n-hexadecanoic acid. The interfacial material was made up of lipid A and undegraded LPS. When chromatographed on Bio-GEl P-60, the degraded polysaccharides were eluted as two incompletely separated peaks (strains NCTC 11168, NCTC 11351, 11041 and 11101) or as one peak (strains NCTC 11392 and E 8035). All peaks appeared close to the total volume of the column. When the different fractions were re-chromatographed on Bio-GEl P-10, the peaks still appeared close to the total volume of the column. These findings indicate that LPS from C. jejuni and C. coli are devoid of long O-antigenic side-chains.

Campylobacter↗
PubMed1984

Chemical composition and biological activity of lipopolysaccharides prepared from type strains of Campylobacter jejuni and Campolybacter coli.

Lipopolysaccharides (LPS) were extracted from seven type strains of Campylobacter jejuni and one type strain of Campylobacter coli with 45 per cent aqueous phenol. The sugar components present in all LPS were glucose, galactose, L-glycero-D-manno-heptose, 2-keto-3-deoxy-octulosonic acid and glucosamine. All but one LPS contained galactosamine, and two strains contained in addition mannose. The fatty acids present were 3-hydroxy-tetradecanoic acid, n-hexadecanoic acid and trace amounts of n-tetradecanoic acid. The LPS preparations examined showed anti-complementary effect, and were able to gelatinize Limulus amoebocyte lysate. LPS of the C.jejuni strain tested (NCTC 11168) was found to be lethal for mice and to produce the local Shwartzman reaction in rabbits.

Animals↗
PubMed1983

Evaluation of the Anaerobe-Tek system for the identification of Bacteroides and Fusobacterium species.

Reference strains and clinical isolates of Bacteroides and Fusobacterium species were examined by the Anaerobe-Tek System (A/T-system). Of 104 strain, only 57 (54.8%) were identified correctly to species level. 38 strains (36.5%) were incorrectly identified and for 9 strains (8.7%) there were no codes in the manufacturers' data base manual. The results indicate that, in our hands, the A/T-system in its present form, is not suitable for the identification of clinical isolates of Bacteroides and Fusobacterium species.

Bacteriological Techniques↗
PubMed1983

Eubacterium saburreum L13 antigen containing a ketohexose as a main sugar constituent.

A periodate-resistant antigen (PS L13) which contained ketohexose and glucose was isolated from the oral microorganism Eubacterium saburreum L13 by trypsin digestion and subsequent gel filtration and ion-exchange chromatography. The ketohexose reacted as fructose would in colorimetric and chromatographic analyses, but not in gas-liquid chromatography. Rabbit antiserum to E. saburreum L13 agglutinated the bacteria and contained precipitins of the immunoglobulin G class specific for PS L13.

Animals↗
PubMed1982

Isolation and chemical composition of lipopolysaccharide from Campylobacter jejuni.

Lipopolysaccharide (LPS) from three strains of Campylobacter jejuni was extracted by aqueous phenol. The sugar components present in all strains were glucose, galactose, L-glycero-D-manno-heptose and glucosamine. One strain contained, in addition, galactosamine. The fatty acids present were mainly 3-hydroxy-tetradecanoic acid and n-hexadecanoic acid. The LPS contained 2-keto-3-deoxy-octonate and phosphorus.

Amino Sugars↗
PubMed1982

Immunochemical studies of lipopolysaccharide and partially degraded lipopolysaccharide from Bacteroides fragilis IPL E323.

A serologically heterogeneous lipopolysaccharide (LPS) was prepared from B. fragilis IPL E323 by phenol-water extraction and purification by ultracentrifugation. The LPS was split by hydrolysis with 1 per cent acetic acid into an acid-soluble polysaccharide and insoluble material. Gel filtration of the acid-soluble material on Bio-Gel P-60 gave a high-molecular-weight fraction eluted with the void volume (Vo), which was serologically heterogeneous, and low-molecular-weight materials eluted at 2.5 x Vo and 2.7 x Vo. Some material was also eluted at 2.9-3.0 x Vo. The oligosaccharides eluted at 2.5 x Vo and 2.7 x Vo showed an antibody-neutralizing capacity similar to that of the parent LPS. Galactose, glucose and rhamnose were the only sugars present in these fractions. The material eluted at 2.9-3.0 x Vo, which contained the same neutral sugars, but at another molar ratio, was serologically inactive. SImilar results were obtained when LPS from three other B. fragilis strains were treated in the same way.

Bacteroides fragilis↗
PubMed1982

Immunochemical studies of partially hydrolyzed lipopolysaccharide from Fusobacterium nucleatum ATCC 10953.

Fusobacterium nucleatum ATCC 10953 LPS was split by hydrolysis with 1 per cent acetic acid into acid-soluble polysaccharide and lipid A. Gel filtration of the acid-soluble polysaccharide on Bio-Gel P-60 gave a high-molecular-weight fraction eluted with the void volume (Vo), and a fraction eluted at 2.4 x Vo. The high-molecular-weight fraction was serologically active, and contained glucose as the only sugar. The other fraction, which was serologically inactive, contained L-glycero-D-manno-heptose, galactose, glucosamine, keto-deoxy-octonate, and phosphorus. The fraction eluted at 2.4 x Vo is thought to constitute the polysaccharide core region, whereas the high-molecular-weight fraction may represent O-antigenic side chains.

Chromatography, Gel↗
PubMed1982

Chemical composition, ultrastructure and some serological properties of lipopolysaccharides from Leptotrichia buccalis.

Lipopolysaccharide (LPS) was extracted with aqueous phenol from Leptotrichia buccalis strains L 11, ATCC 14201 and ATCC 19616. Virtually all the LPS was found in the water phase. LPS could also be extracted with phenol/chloroform/petroleum ether, but not with cold trichloroacetic acid. All LPS preparations contained D-glycero-D-manno-heptose, galactose, glucose, glucosamin, n-dodecanoate, 3-hydroxy-n-tetradecanoate and phosphorus. In addition LPS from L11 contained 2-keto-3-deoxyoctonate and an unidentified aldose. LPS from L11 was serologically distinct from LPS of ATCC 14201 and ATCC 19616. LPS from the two latter strains crossreacted.

Amino Sugars↗
PubMed1982

Composition of peptidoglycans in Bacteroidaceae: determination and distribution of lanthionine.

Peptidoglycans of organisms belonging to the strictly anaerobic family Bacteroidaceae were investigated for the presence of lanthionine. Different procedures for the quantitation of lanthionine were compared. Performic acid and peroxide oxidation procedures on 35S-labeled peptidoglycan from Fusobacterium nucleatum Fev1 resulted in low yields of cysteic acid (42 and 60%, respectively) and many other additional unidentified oxidation products. Lanthionine was, however, recovered in high yield (89% or more) from acid hydrolysates of unoxidized peptidoglycans. Lanthionine was found exclusively in some species of Fusobacterium, in particular F. nucleatum, F. necrophorum, F. russi, and F. gonidiaformans, for which lanthionine may be ascribed a function as a taxonomic marker. Peptidoglycans of these bacteria are thus proposed to belong to a new chemotype, assigned A1 delta. One strain of Fusobacterium, F. mortiferum VPI 0473 contained both lanthionine and diaminopimelic acid in about equal proportions. Species of F.plauti had a composition atypic of gram-negative cells. Chemotypic differences were also indicated among the species of Bacteroides investigated. Thus, some species contained lysine and not diaminopimelic acid as the major dibasic amino acid (e.g., F. asaccharolyticus). It is concluded that peptidoglycans of gram-negative organisms constitute a somewhat more heterogeneous group than hitherto assumed.

Alanine↗
PubMed1981

Fatty acids of Fusobacterium species: taxonomic implications.

Fatty acids of Fusobacterium species were examined by gas-liquid chromatography. Fusobacterium nucleatum, F. necrophorum, F. mortiferum, F. gonidiaformans and F. varium showed similar patterns, characterized by the presence of 3-hydroxytetradecanoate, n-tetradecanoate, hexadecenoate, n-hexadeconoate, ocadecenoate, n-octadecanoate and a component having the properties of octadecadienoate. Fusobacterium nucleatum contained 3-hydroxyhexadecanoate as a distinctive character. Simpler fatty acid patterns characterized by the absence of 3-hydroxytetradecanoate and other hydroxy fatty acids were observed in F. plauti, the single strain of F. prausnitzii and in the majority of strains classified as F. russii and F. naviforme. Neither methyl-branched nor cyclopropane fatty acids could be detected in any of the strains examined. In addition to fatty acid methyl esters, the chromatographic profiles of all species except F. mortiferum, F. gonidiaformans and F. naviforme contained substantial amounts of fatty aldehyde dimethyl acetals of chain lengths C14 to C18.

Chromatography, Gas↗