- Volume 131, Issue 09, 1985

Summary: A possible colonization factor, E8775, has previously been described for enterotoxigenic Escherichia coli strains of serogroups O25, O115 and O167. Re-examination of these strains by immunodiffusion has revealed that the antigenic nature of this factor, renamed putative colonization factor (PCF) 8775, is more complex than was first thought. All the strains of serogroup O25 tested possessed two antigenic components, termed CS4 and CS6, and gave mannose-resistant haemagglutination (MRHA) of human and bovine erythrocytes. Spontaneous variants possessing CS6 only did not give MRHA. Strains of serogroups O115 and O167 had the antigenic components CS5 and CS6, and gave MRHA of human, bovine and guinea-pig erythrocytes. Using immune electron microscopy, the components CS4 and CS5 were identified as fimbriae. No fimbriae were associated with CS6.

Summary: Microaerophilic spiral organisms may be isolated frequently from samples of gastric mucus taken from patients undergoing gastroscopy. The ultrastructure of these gastric campylobacter-like organisms (‘Campylobacter pyloridis’) shows that they have greater affinities with Spirillum than with Campylobacter.

Summary: Serratia marcescens New CDC O14:H12 contains major outer membrane proteins of 43.5 kDal, 42 kDal (the porins) and 38 kDal (the OmpA protein) which can be separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Immunoblotting of whole cell or outer membrane preparations using antiserum raised against the whole cells revealed similar complex patterns of antigens. The OmpA protein was the major immunogen, although six other outer membrane proteins were also detected; the porins reacted only weakly with antibodies in this system. Immunoabsorption of antisera with whole cells showed that only the O antigenic chains of lipopolysaccharide and the H (flagella) antigens were accessible to antibody on the cell surface. Failure to detect the OmpA protein and other envelope antigens in this way suggests that their antigenic sites are not able to react with antibodies and are possibly masked by the O antigen.

Summary: Rabbits infected intravenously with Treponema pallidum were not markedly febrile, and the pyrogenicity of treponeme preparations administered intravenously to rabbits was negligible. The antibiotic polymyxin B did not induce any ultrastructural changes on the treponemal surface and was not lethal (immobilizing) for T. pallidum, which was, however, highly susceptible to detergents such as SDS. Extraction of treponemes with Triton X-100 removed the outer membrane (despite the presence of Mg2+) as shown by electron microscopy, and solubilized a limited number of proteins detectable by SDS-PAGE, including a dominant antigen (47 kDal) demonstrated by immunoblotting. None of the proteins were heat-modifiable. Periodic acid-silver staining of polyacrylamide gels for carbohydrate together with protease K digestion did not demonstrate major carbohydrate components in whole treponemes, or in the Triton-soluble fraction. Surface iodination of intact treponemes revealed very little surface exposure of treponemal proteins, although a protein which co-migrated with host albumin was labelled and appeared to be associated with the treponemal surface. Many treponemal proteins were, however, labelled when iodination was done in the presence of Triton. These observations indicate that the outer membrane of T. pallidum differs significantly from those of many Gram-negative pathogens.

Summary: Anaerobic fungi were isolated from rumen digesta of sheep and cattle and were purified using a plate culture technique. The isolates were successfully cultured on a semi-defined medium which lacked rumen fluid, and on a defined medium.

Summary: The polyol gel Lutrol FC127 was used to solidify culture media. This gel liquefies as the temperature drops below a critical value for the concentration used. This property was used to recover whole colonies of Thermoactinomyces sp. for examination of the substrate mycelium by scanning electron microscopy.

Summary: Antisera against the Calvin cycle enzymes d-ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and phosphoribulokinase (PRK) have been used in immunogold electronmicroscopy studies on cell sections of the cyanobacterium Chlorogloeopsis fritschii. RuBisCO antiserum consistently labelled the carboxysomes (polyhedral bodies) and the cytoplasm. PRK antiserum-labelling occurred in the cytoplasm but not in the carboxysomes. The data agree with in vitro enzyme localization studies, and confirm that both enzymes occur in the cytoplasm and that RuBisCO, but not PRK, also occurs in the carboxysomes of C. fritschii.

Summary: Lipoteichoic acid (LTA) from Lactobacillus casei YIT 90 18 or Lactobacillus fermentum YIT 01 59 augmented the resistance of C57BL/6 mice to infection with Pseudomonas aeruginosa, but conferred no resistance to Listeria monocytogenes. It is suggested that LTA was unable to activate macrophages.