- Volume 32, Issue 2, 1963

SUMMARY: Seven strains of micrococci which produce violet pigment were studied. We recommend that the names Staphylococcus flavocyaneus Knaysi and Micrococcus polychromus Makarova should be regarded as synonyms of M. luteus (Shroeter) Cohn, and consider that M. violagabriellae Castellani belongs to the species Staphylococcus epidermidis. For the practical diagnosis of micrococci we recommend that those strains which form a violet pigment, which do not give acid in glucose peptone water and do not form acetylmethylcarbinol, should be identified as atypical strains of Micrococcus luteus.

SUMMARY: Staphylococcus flavocyaneus produces at least two pigments on glucose yeast-extract agar; a violet diffusible pigment and a yellow non-diffusing pigment. On some media the production of violet diffusible pigment is inhibited. In broth cultures of this organism a mutation takes place giving rise to yellow-pigmented mutants which have lost the ability of producing the violet pigment. A considerable accumulation of these mutants occurs in cultures on both solid and liquid media. No reversion to the violet-pigmented state or other change in pigmentation in the mutants has been observed.

The yellow-pigmented mutants do not differ from strains of Micrococcus luteus with the exception of some characteristics which are variable within that species. This supports the conclusions of Kocur & Martinec (1963) that Staphylococcus flavocyaneus Knaysi should be regarded as a strain of Micrococcus luteus (Schroeter) Cohn.

SUMMARY: Dictyostelium discoideum uses a wide variety of extracellular materials to accelerate the rate of morphogenesis. The stimulants of morphogenesis do not appear to exert their effect through the action of such factors as buffering, ionic strength, tonicity of the medium, or chelation.

Both glucose and histidine stimulate the rate of incorporation of amino acids into protein but at differing stages of development. Glucose stimulates throughout differentiation while histidine shows maximal stimulatory ability at preculmination (i.e. the stage just prior to complete fructification). The two compounds exhibit a mutual antagonism when added together.

It is concluded that glucose is probably acting as a primary energy source, whereas histidine is not acting in this manner or as a limiting amino acid for protein synthesis.

SUMMARY: ‘Sulphur granules’ of Actinomyces bovis were isolated from a case of bovine actionmycosis. These were examined in ultrathin sections with the electron microscope, in stained sections with the light microscope or in wet mounts before and after chemical extraction with the light and phase microscope. In addition chemical analyses were done on the granules and on organisms grown in vitro. The combined results showed the granule is a mycelial mass of Actinomyces bovis cemented together by a polysaccharide+protein complex and containing about 50% calcium phosphate. With the exception of the calcium phosphate, the granule had essentially the same composition as organisms grown in vitro. It is concluded that the ‘clubs’ of the granule represent normal hyphae encapsulated with the same polysaccharide+protein complex, that the basic structure of the granule represents the organism itself or products formed by it and that the mycelial mass is mineralized by calcium phosphate derived from the host as a result of phosphatase activity of the host and organism.

SUMMARY: Antisera were prepared to several strains of influenza virus (grown in the chick embryo), to purified Vibrio cholerae neuraminidase and to partially purified neuraminidase from chick chorioallantois. The ability of the antisera to inhibit the action of each enzyme on substrates of different molecular weight was tested. The substrates used and their molecular weights were sialyl lactose (640), fetuin (48,000) and ovine submaxillary gland mucin, OSM (1 × 106). Antiserum to V. cholerae and avian neuraminidase inhibited strongly the action of the homologous enzyme on each substrate. Antiserum to viral neuraminidase inhibited almost completely homologous action on fetuin and OSM but only partially the action on sialyl lactose. LEE influenza virus was grown in embryonated eggs and in cultures of calf kidney cells and from each preparation a soluble neuraminidase was isolated. Antiserum to the egg-grown virus inhibited the enzyme of both viruses not only in the intact virus particle, but also after separation in the form of a soluble, low molecular weight product. There was little or no serological cross-reaction between any enzyme and heterologous antisera, with one exception. Antiserum to avian neuraminidase partially inhibited (fetuin, but not sialyl lactose, as substrate) the soluble enzyme derived from egg-grown LEE virus, but not from virus grown in cultures of calf kidney cells. It was concluded that the soluble enzyme prepared from LEE virus is a virus specific product but also carries some antigenic determinants characteristic of host specificity.

SUMMARY: Electron microscopic study of vibrio flagella by using the negative staining technique revealed differences in chemical reactivity as between the sheath and core components. The sheath was easily degraded by autolysis and exposure to acid and urea, whereas the core was relatively resistant.

These differences suggest that the sheath and core are of different composition and that, whereas the core consists of the protein ‘flagellin’, the sheath is probably of cell-wall origin.

SUMMARY: A study of 22 haemagglutinating viruses was made to see whether by treating the viruses and the receptors on the red cells with a variety of physical and chemical agents, a convenient means could be devised for identifying and classifying these viruses, while throwing some light on the chemical basis of the haemagglutination reaction. The viruses were submitted to 13 different treatments; acid, urea, p-chloromercuriben-zoic acid, deoxycholate and possibly bisulphite might be useful for the classification of unknown agents since they gave similar results with all members of a biological group. Other treatments (e.g. formaldehyde) gave results which varied from strain to strain in such a group of viruses and might be useful for genetic studies. The red cells were treated in nine different ways; formalin, papain, chymotrypsin, periodate, receptor-destroying enzyme, (RDE) and swine influenza virus each prevented agglutination by one or two viruses (apparently by inactivating cell receptors). These results were complementary to those with the virus haemagglutinins. The importance of standardized conditions of test are emphasized.

SUMMARY: Antibiotic production in liquid media by Staphylococcus aureus strains of bacteriophage ‘type 71’ was poor as measured by cup assays against susceptible corynebacteria. Aerobic incubation in freshly prepared tryptic-digest broth containing a fermentable carbohydrate and adjusted to pH 7.8 gave the greatest yields. The antibiotic material was not obtained in a pure state, but was concentrated by evaporation of crude solutions. These were prepared by adding trichloroacetic acid to broth cultures and centrifuging to remove the organisms. The antibiotic was stable and relatively heat-resistant under acid conditions, but was rapidly destroyed when alkaline; it diffused slowly through cellophan, was adsorbed by charcoal, and was inactivated by trypsin but not by pepsin. These properties suggest that it may be protein or polypeptide in nature. Inhibitory activity by type 71 cocci was shown in mixed broth cultures against other non-inhibitory strains of Staphylococcus aureus, and was similar to that previously observed on solid media.

SUMMARY: Fatty acids are required for the growth of Pityrosporum ovale (Bizzozero) Castellani et Chalmers; myristate or palmitate satisfies this requirement. Oleate increases the crop of organism in a medium containing limiting concentrations of myristate or palmitate. When [1-14C]-myristate was added to the medium the cells of P. ovale contained myristate, palmitate, stearate, oleate and linoleate with approximately the same molar specific radioactivity as myristate. Thus P. ovale can synthesize both saturated and unsaturated fatty acids of higher molecular weight from myristate.

SUMMARY: Wall and intracellular teichoic acids were prepared from several strains of staphylococci. Intracellular glycerol teichoic acids were found in all the cases examined but their detailed chemical composition was not determined. The presence and structure of wall teichoic acids is characteristic of the different species; thus, strains of Staphylococcus aureus all possess a teichoic acid containing glucosamine in their walls; this was shown previously to be indistinguishable from the group-specific antigen. Similarly, S. saprophyticus strains contain in their walls a glycerol teichoic acid with glucosyl substituents probably identical to the group-specific precipitinogen, polysaccharide B. The species S. lactis is heterogeneous: three groups are distinguishable, one without wall teichoic acid and the others with a teichoic acid containing glucosamine or galactosamine.

SUMMARY: Calf kidney cell cultures persistently infected with foot-and-mouth disease virus (FMDV) resist challenge with related and unrelated viruses. Attachment of challenge virus to persistently infected cells is not impaired. A challenge with viral ribonucleic acid (RNA) will not overcome the resistance of persistently infected cells. The initiation of persistence is correlated with the amount of interferon produced in the cells. It is concluded that interferon plays a major role in initiation and maintenance of the carrier state of the cells.

SUMMARY: One-step growth experiments with bacteriophage ϕR showed that the yield of phage increased with increasing Mg2+ concentration. The function of Mg2+ was not primarily that of a lysis cofactor since the titre of intra-cellular phage was also dependent upon metal ion concentration. Phage development could be promoted by addition of Mg2+ after the end of the normal latent period. This stimulatory action was not appreciably inhibited by chloramphenicol or respiratory poisons, though it was abolished at low temperature and gradually became less as the time between infection and Mg2+ addition was increased. Qualitatively similar effects on phage growth were obtained with other divalent metal ions and with some polyamines. It is concluded that all these substances act at a late stage in the intracellular development of phage ϕR, possibly at some step involving the neutralization of nucleic acid. Whether or not Mg2+ ions are also required for the release of phage particles cannot be determined from the present experiments, though some of the results suggest that they may be.

SUMMARY: Immature sporangiospores of Rhizopus nigricans and R. sexualis were relatively thin-walled, although thickened longitudinal ridges were already discernible. The position of the nuclei suggested that they had recently divided; the mitochondria were globose and similar to those of vegetative hyphae; the protoplast was surrounded by a thin plasmalemma and contained numerous food globules. The endoplasmic reticulum was sparse. Mature spores had a thick wall of reticulate structure and contained large contorted mitochondria. The first visible stage in germination was the formation of an inner cell wall of tangential elements resembling that of the vegetative hyphae and contrasting with the original spore wall. The mitochondria increased in number, probably by division of the large contorted ones of the dormant spore, and were again regularly globose. The original spore wall became considerably stretched and finally ruptured to allow the germ tube enveloped in the newly formed elastic inner wall to emerge.

SUMMARY: Resting organisms of Shigella flexneri serotype 3 are able to synthesize soluble and ribosomal ribonucleic acid (RNA) in the presence of chloram-phenicol. The antibiotic stimulates the synthesis of soluble RNA but has no apparent effect on ribosomal RNA production. In contrast, chlortetracycline, which also suppresses formation of protein, stimulates soluble RNA synthesis and inhibits ribosomal RNA synthesis. The soluble RNA of the chloramphenicol-treated organisms possesses amino acid accepting activity comparable to that of the soluble RNA of untreated organisms. The findings indicate that chloramphenicol does not promote the synthesis of biologically inactive soluble RNA. The stimulation of soluble RNA synthesis appears to be the result, rather than the cause, of the inhibition of protein production by the antibiotic.