- Volume 60, Issue 3, 1970

SUMMARY: Membrane glycerol teichoic acid has been extracted from Lactobacillus fermenti NCTC 6991 by two different procedures. Phenol extraction gave a complex of teichoic acid with glycolipid and phospholipid (lipoteichoic acid). Trichloracetic acid extraction resulted in degraded lipoteichoic acid and free teichoic acid chains. The teichoic acid is a 1:3 phosphodiester linked glycerophosphate polymer substituted with D-alanine, D-galactose and a disaccharide of D-galactose and D-glucose. The significance of lipoteichoic acid as a membrane constituent is discussed.

SUMMARY: The membrane glycerol teichoic acid of group F lactobacilli (e.g. Lactobacillus fermenti) has been identified as the group antigen. The most active preparations, obtained by phenol extraction, reacted readily with antisera and were antigenic when injected into rabbits with Freund's adjuvant. The products obtained by the action of trichloracetic acid were separable into a high molecular weight fraction, which reacted well with antiserum but was not a very effective antigen, and a low molecular weight fraction which was not antigenic and reacted weakly with group antisera. Specificity of the group antigen depends primarily on galactose with glucose being a minor contributor. However, the ability of galactose and glucose to inhibit the precipitin reaction differs considerably with different antisera. Teichoic acids from other strains of L. fermenti cross-reacted with the group antisera to varying extents but preparations from L. casei strains reacted only weakly.

SUMMARY: Teichoic acid-lipid complexes from Lactobacillus fermenti NCTC 6991 absorb to normal sheep red blood cells. Sensitized cells are agglutinated by specific antisera, the titres of representative sera being 1600 to 3200. Lipid-free teichoic acid does not sensitize red blood cells but inhibits haemagglutination. Haemagglutination is inhibited completely by intact cells of L. fermenti NCTC 6991, but only partially by other strains of L. fermenti. Strains of lactobacilli of other serological groups absorb a variable proportion of antibody. The group F antigen is a membrane teichoic acid and the significance of the absorption by intact bacterial cells is discussed.

SUMMARY: Spores of various species of the genera Bacillus and Clostridium were inactivated by hydrostatic pressures up to 8000 atmospheres. Inactivation was a function of holding time at pressure rather than of the compression and decompression stages. Inactivation generally proceeded more rapidly at high than at low temperatures; below about 50° there was a well defined optimum pressure for inactivation, but above about 50° an increase in pressure up to 8000 atmospheres caused progressively more inactivation.

Inactivation was decreased at extremes of pH value and by high ionic strength solutions. A proportion of the spores pressurized under certain conditions became heat-sensitive. These observations, and the chemical, phase-contrast, and electron-microscopic changes seen in pressurized spores, suggested that pressure caused inactivation of spores by first initiating germination and then inactivating the germinated forms.

SUMMARY: Hydrostatic pressure initiated germination of bacterial spores in nutrient-free media. Those spores which were most dormant towards chemical germinants at I atmosphere pressure were also the most resistant to germination by pressure treatment. Germination by high pressure treatment was characterized by temperature and pH optima, like germination at atmospheric pressure. Germination initiated by pressure was inhibited by metabolic poisons and was potentiated by low concentrations of various nutrients including some of those which are normally germinative (at higher concentrations) at atmospheric pressure. In particular, L-alanine and closely related α-amino acids, but not their breakdown products, potentiated germination initiated by pressure. Study of potentiation by D-alanine (which strongly inhibits germination initiated by L-alanine at I atmosphere pressure) revealed that high pressures caused an increase in the rate of racemization of alanine by spores. Germination by pressure probably resulted from acceleration of some germination reaction which is normally negligibly slow at a pressure of I atmosphere, and also from an increase in permeability of some barrier within the spore to L-alanine and related α-amino acids.

SUMMARY: Treatment with mercaptoethanol caused spores of various bacteria to become sensitive to lysis by lysozyme, a spore enzyme and hydrogen peroxide; further treatment with alkali caused greater sensitization to these lytic agents. Alkali removed a protein from the outer coats of mercaptoethanol-treated spores. The protein from Bacillus cereus, B. coagulans and Clostridium sporogenes contained high levels of acidic and basic amino acids; that from B. coagulans contained a high proportion (over 7% of its residues) of tyrosine. Electron microscopy of thin section and freeze-etch samples showed that the alkali-soluble protein contributed to a striking banding pattern containing 57 Å spaced fibres on the outer surface of B. coagulans spores. This layer may function as a protection against the enzymes of potential predators.

SUMMARY: Electron microscope observations on the micronucleus of Paramecium aurelia showed that the mitotic spindle was organized within the nuclear envelope. At the intranuclear metaphase plate stage some microtubules were attached to chromosomes by localized centromeres and other interzonal microtubules ran between the chromosomes. The interzonal microtubules elongated tenfold during telophase and were tightly packed in a narrow cylindrical membrane-limited stem of the spindle. Some microtubules persisted in the micronucleus during interphase and formed a layer near the nuclear envelope. There were scattered groups of microtubules in the isthmus of the macronucleus during its amitosis. The nuclear envelope remained intact. Large and small bodies persisted throughout the amitosis and the microtubules pass between them. Before the first postconjugal fission there was a stage during which the two macronuclear anlagen were separated by a sheet of cytoplasm only 0.3 μm. wide.

SUMMARY: In Paramecium aurelia, pretrichocysts originate in the endoplasm as undifferentiated vesicles. They develop in the endoplasm and then migrate to sites below the pellicle to become juvenile trichocysts. The maturation process takes place below the pellicle and involves a physical expansion and change in staining affinity of the body material of the trichocyst. Cold fixation usually caused mature trichocysts to be extruded, but the use of osmium tetroxide fixative at 37° allowed them to be fixed without extrusion. Juvenile trichocysts cannot be extruded. In P. bursaria and P. aurelia after osmic fixation the body of the mature trichocyst, unlike the juvenile trichocyst, had no staining affinity for either potassium permanganate or toluidine blue. During fission in P. aurelia, mature trichocysts were present only in small numbers at the poles of the protozoa remote from the furrow. Juvenile trichocysts mature in the first hour of the interfission period.

SUMMARY: A survey of the walls of over 80 bacterial species has been carried out using chromatographic and colorimetric techniques to demonstrate the presence of 2-keto-3-deoxy-octonic acid (KDO) and or sialic acid. In most Gram-negative bacteria KDO but not sialic acid was found in the wall, whereas the walls of Gram-positive bacteria contained neither compound.

SUMMARY: Nine isolates of cellulolytic, Gram-positive motile rods obtained from the rumen contents of sheep fed on teff hay were identified as belonging to the genus Cillobacterium Prévot. In most respects the organisms resembled C. cellulosolvens and it is proposed that the definition be extended to include the characteristics of the present strains.

SUMMARY: Ultrasonic treatment of double-walled cysts of Schizopyrenus russelli led to the removal of the outer wall. These single-walled cysts excysted readily in aqueous extract of Escherichia coli, as did normal double-walled cysts. There was a marked delay in the excystment of single-walled cysts obtained by ultrasonic treatment of the normal cysts treated with p-chloromercuric benzoate (p-CMB) or emetine, similar to that obtained with normal cysts. The action of p-CMB was annulled by reduced glutathione. These findings suggest that the sites of action of excystment-inducing and excystment-blocking agents are on or inside the inner cyst wall and that these agents are able to permeate the outer cyst wall.

SUMMARY: Oxygen uptake by Azobacter chroococcum (NCIB 8003) grown in continuous culture without fixed nitrogen and with a low mannitol concentration (2°5 g./1.) and treated with lysozyme and EDTA was inhibited by ATP but not by ADP; ADP frequently prevented inhibition by ATP. In preparations obtained by disrupting bacteria suspended in a mixture of defatted bovine serum albumin, sucrose and MgCl2 in the French press, ATP inhibited oxygen uptake with either sodium succinate or sodium isocitrate as substrates and ADP prevented this inhibition; oxygen uptake with glucose-6-phosphate was inhibited by ATP or ADP. A form of respiratory control by nucleotides may thus occur in Azotobacter. Acetylene reduction (a measure of nitrogenase activity) by bacteria treated with lysozyme and EDTA was inhibited by ATP; this was attributed to inhibition of oxygen uptake by ATP causing inhibition of nitrogenase by oxygen. High oxygen solution rates inhibited nitrogenase in whole bacteria or in bacteria treated with lysozyme and EDTA; when the oxygen solution rate was lowered nitrogenase functioned immediately. These observations are probably expressions of processes which protect nitrogenase in whole bacteria from damage by oxygen.

SUMMARY: Claviceps fusiformis usually produces a stable viscous glucan during submerged culture fermentations. A new strain 139/2/1 G of the fungus, which subsequently autolysed this glucan to glucose, was studied and the autolysis ascribed to a constitutive β1 3 glucanase and a β-glucosidase which were detected as soon as the fungal hyphae differentiated to a sclerotial form. The glucanase production followed a sigmoid pattern, reaching a maximum within 12 days, and the liberated glucose contributed to renewed growth towards the end of the fermentation. A sucrase and a maltase were also detected. Maximum glucan autolysis was achieved by using a large spore inoculum. This maintained minimal viscocity throughout the fermentation and, by maintaining adequate aeration, has since facilitated ergot alkaloid production by the organism.