- Volume 8, Issue 3, 1953

SUMMARY: Cultures of Thiobacillus thiooxidans, Th. thioparus, Th. novellus, Thiobacillus B (Waksman, 1922a), strains ‘T’ and ‘K’ (Trautwein, 1921) and Th. concretivorus, Thiobacillus X and the ‘M’ strains, organisms isolated from concrete (Parker, 1945, 1947), were examined to elucidate the mode of oxidation and to establish the identity of the organisms recently isolated from corroded concrete.

Thiosulphate was oxidized by all these bacteria. Th. thiooxidans, Th. concretivorus and Thiobacillus X first converted it to tetrathionate and sulphate and then oxidized the tetrathionate to sulphate and free sulphuric acid. Thiobacillus X differed from the other two in that, owing to a lesser acid tolerance, some tetrathionate was found in the final products of oxidation. Th. thioparus converted thiosulphate to sulphate and sulphur, followed by partial oxidation of the sulphur to sulphuric acid. Th. novellus produced sulphate and sulphuric acid. Thiobacillus B, the ‘T’ and ‘K’ strains and the ‘M’ strains formed sulphate and tetrathionate with temporary increase in pH value; only Thiobacillus X oxidized tetrathionate, yielding sulphate and sulphuric acid.

Elementary sulphur was oxidized by Th. thiooxidans, Th. concretivorus, Thiobacillus X and Th. thioparus; the rates of oxidation decreased in that order, and the only product was sulphuric acid.

Hydrogen sulphide was oxidized only at low concentrations and only by Th. concretivorus and Thiobacillus X; sulphuric acid was the end-product, and elementary sulphur may have been an intermediate.

Thiobacillus X differed from Th. thiooxidans in pH range for growth and from Th. thioparus in its method of oxidation of thiosulphate, tetrathionate and H2S. It appeared to fit earlier descriptions of Th. thioparus by Nathansohn (1902) and Beijerinck (1904) more closely than the strain described as Th. thioparus by Starkey (1934a). The ‘M’ strains were similar to Thiobacillus B and the ‘T’ and ‘K’ strains of Trautwein.

SUMMARY: Submerged growth of four dermatophytes, Microspoum canis, M. gypseum, Trichophyton rubrum and T. mentagrophytes has been obtained by shaking during growth. The respiratory rate (μl. O2 consumed/hr./mg. dry weight) of washed cells from 4–6-day cultures was between 7 and 12. As commonly observed with other fungi, addition of substrate to washed respiring cells did not much increase the respiratory rate. Acetone powders were prepared from cells grown in shaken culture. Such preparations oxidatively deaminated amino-acids slightly, about as much as similar preparations of Penicillium chrysogenum. A preparation of the enzyme asparaginase was extracted from Microsporum gypseum and some of its characteristics studied.

SUMMARY: H2S was evolved from soil treated with CCl4 when moistened with sucrose and (NH4)2SO4 solution and incubated aerobically. H2S formation took place when the soil moisture was less than field capacity, and over a range of pH values from 5 to 8. The organism responsible was isolated and identified as Bacillus megaterium Several strains of this organism reduced sulphate in well-aerated sterilized soil and liquid media but not in soil or liquid incubated anaerobically.

The action of CCl4 in fresh soil is to check or destroy certain fungi and bacteria which normally inhibit sulphate reduction by B. megaterium. Some of these organisms were isolated and shown to be sensitive to CCl4 and to inhibit sulphate reduction by B. megaterium in sterilized soil. The isolates did not exhibit antibiotic action when grown in certain defined media.

SUMMARY: Discrepancies found in the use of three previously published micromethods for fermentations were traced to at least three possible sources of error: contamination of the water used for making suspensions; contamination of capillary tests from non-sterilizable Perspex plates; chemical breakdown or contamination of certain sugar solutions. To overcome these discrepancies one of the methods was modified; the other two were abandoned.

Suspension concentration is important and, measured as opacity, should not be less than the equivalent of 109 Bacterium coli cells/ml. Sugar concentration is much less critical, and 0·1 m concentrations are recommended. Dilution of the test mixture with 0·5 ml. sterile water speeds up fermentations; the addition of formalin or thiomersalate inhibits certain enzyme systems but does not hinder glucose fermentation.

SUMMARY: Hydrogen sulphide production by growing cultures and non-multiplying suspensions was compared and the factors influencing the sensitivity of the tests were investigated. Cysteine hydrochloride (0·01 %) was added to Lemco broth to provide a medium with a standard source of sulphur. H2S was detected with lead acetate papers more readily than by lead acetate agar.

Suspensions were tested with cysteine, sodium thiosulphate and sodium sulphite; the organisms investigated were mainly Bacteriaceae and seldom failed to produce H2S from cysteine; sodium thiosulphate was less readily attacked; sodium sulphite was unsuitable for this technique. Media commonly used for testing the capacity of bacteria to produce H2S are reviewed and the value of this test in bacterial classification discussed.

SUMMARY: The propagation of Vi-phage II on ‘degraded Vi strains’ of Salmonella typhi did not yield phage preparations bearing any trace of the specificity of the original Vi type from which the degraded strains had sprung.

Ten different standard Vi-typing phages were grown on a selection of degraded Vi strains. The phages could be separated into two groups: six underwent a change which appeared to be a phenotypic modification, and four were propagated unchanged. It seems probable, however, that all adapted Vi-typing preparations are phenotypic modifications of Vi-phage II.

In the attack of Vi-phage II on the typhoid bacillus the Vi antigen apparently plays a part only in the adsorption of the phage. The stages of phage growth succeeding adsorption seem to be independent of the Vi antigen, and it is in the regions of the bacterial cell concerned with these stages that Vi-type specificity seems to reside.

SUMMARY: In Sitka spruce nursery plots the numbers of amoebae in steam-treated soil rose with the increase in the bacterial population. The population of amoebae over a period of seven months was much higher in this soil than in the untreated or the formalin-treated soils. The formalin-treated soil had significantly lower numbers of amoebae compared with the untreated soil over a period of one year, although the bacterial numbers were often higher in the former than in the latter. It is suggested that the unsuitable quality of bacterial food supply might be responsible for keeping the numbers of amoebae in check in the formalin-treated soil. Double formalin treatment seemed to suppress further the numbers of amoebae.

SUMMARY: Haemin was found in all specimens of purified preparations of Rous I, Duran-Reynals B, D and V, Fujinami, and MH2 viruses, and also in macromolecular preparations from non-filterable fowl sarcomas and normal fowl tissues. The amounts were not constant in different batches of Rous I, and it was shown that this virus would strongly adsorb pure haemin from solution. It is suggested that most, probably all, of the haemin encountered in these preparations was derived from the host blood. Adsorbed haemin had no effect on the oxidative destruction of the virus, but slightly altered its physical properties.

SUMMARY: The optimum temperature for the growth and sporulation of Trichophyton persicolor was 25–30°; 40° inhibited growth. A range of pH values from 4 to 10 was compatible with growth, the optimum pH value being slightly less than pH 7. Macroconidia were produced over a narrower range and were most abundant at pH 8. Percentage germination and length of germ tube were greatest at 100 % humidity. No germination occurred at humidities of below about 95 %. Exposure to light had no effect on growth rate, sporulation or pigmentation.

The carbon compounds which supported best growth were mannose, glucose, mannitol and maltose. Nitrates were not utilized, and ammonium sulphate, urea and asparagin supported poor growth. The amino-acids leucine, glycine, histidine and cysteine were utilized; with all other single amino-acids tested, growth was negligible. Methionine and phenylalanine were inhibitory.

T. persicolor was autotrophic for vitamins. It grew as well on a vitamin-free medium as on the basal medium.

The elements zinc, iron, copper and manganese, as sulphates, stimulated the growth and sporulation of T. persicolor on a medium treated for the removal of trace elements.

SUMMARY: Azotobacter chroococcum exists in two cytologically distinct vegetative forms. In one the appearance is that of a typical bacterial resting cell, with a large vesicular nucleus. In the other the cytoplasm appears homogeneously vacuolated and refractive; this is correlated with a high lipid content. Gonidia of two types are produced from the nucleated cells. The more common are tiny bacilli with polar flagella; these are released from the lumen of the mother cell and reproduce by fission. Larger gonidia, resembling miniature vegetative cells, develop within the mother cell, which becomes greatly elongated. These large gonidia do not appear to divide but grow directly into vegetative cells. Mother cells of both kinds may be Grainpositive.

SUMMARY: The thermophilic actinomycete Micromonospora vulgaris resembles known mesophilic members of the genus Micromonospora in reproducing by means of small retractile spores borne singly on lateral branches of the vegetative mycelium. Its distinctive feature is the consistent production of a secondary aerial mycelium under optimal laboratory cultural conditions and in grass composts during the high temperature phase. This aerial mycelium is composed of abundantly branched, hydrophobic filaments which rapidly segment. The cells in these filaments may in turn give rise to similar refractile spherical spores borne singly on very short lateral branches. The reproductive pattern here described is one of the most complex yet known among the actinomycetes. It is thought that the aerial phase of development is intimately associated with the thermophilic nature of the organism.

SUMMARY: The respiration of Micromonospora vulgaris at 60 was studied by means of the Warburg technique. Various cultural methods and heat treatments were used to separate the different growth phases of this structurally complex organism. One- to two-day growths bearing aerial mycelium were most active. Spores were inactive. Vegetative mycelium which developed within 24 hr. in the Warburg vessels was active, but similar 1-day or older growth harvested from cultures proved to be inactive.

SUMMARY: Six strains of Actinomyces israelii were trained to grow in continued subculture on a medium composed of 99 volumes of 1 % casein hydrolysate + 1 volume of heart broth, the mixture containing 0·5 % (w/v) glucose. Poor growth of limited viability was obtained in a medium consisting of 1 % casein hydrolysate + 0·5% glucose (w/v) only. The addition of a wide variety of different amino-acids, fatty acids, growth factors and mineral salts to certain of the less complex media did not compensate for the partial or complete omission of the heart broth. Of the glucose supplied in relatively complex media about 40 % was utilized, and lactic acid equivalent to 30-60% of the glucose utilized appeared in the medium.

SUMMARY: The generic name Aerococcus is proposed for a group of aerobic Grampositive cocci that are commonly found in the air of occupied places and in dust. The most characteristic features of the organisms are ability to grow in the presence of 40 % bile and to produce greening on blood agar. They are catalase-negative, and do not show chain-formation in culture.

SUMMARY: Fifty-three strains from six species of the genus Bacillus were tested for their ability to produce gelatinase and to disintegrate the collagen matrix of bone. Some strains of B. cereus and B. anthracis produced a true collagenase which brought about complete disintegration of the collagen substrate, while strains of B. subtilis, B. licheniformis, B. brevis and B. megaterium were either completely inactive or produced only partial disintegration. Collagenase production was always accompanied by gelatinase production but the reverse was not the case. Concentrated culture filtrates of B. cereus were shown to contain collagenase and gelatinase whereas those of B. subtilis contained contained gelatinase only.