- Volume 12, Issue 1, 1955

Summary: With spores of Streptomyces sp. strain T12 irradiated at doses of ultraviolet light up to 1000 ergs/mm.2 and then incubated in distilled water, both the proportion of survivors and the proportion of induced variants amongst the survivors rose progressively to maximal values as the period of incubation was increased. The maximal proportion of variants was attained before the maximal proportion of survivors. The rate of increase of survival and the final level of survival were enhanced in the presence of iodoacetate. The rate of increase of variant frequency was enhanced by iodoacetate. but the maximal proportion of variants was not raised. The changes of variant frequency resulting from post-irradiation treatments do not appear to be due to selectively greater increases in the survival of variant spores than of non-variant spores.

Summary: Dispersion of isolated cell walls of Streptococcus faecalis in washed agar provided an opaque medium on which cell-wall decomposing micro-organisms were isolated from soil. All of the organisms isolated on S. faecalis cell-wall agar were Streptomyces spp. The lytic activities of seven isolates of Streptomyces, S. albus, two strains of Micromonospora chalceae, Micromonospora sp., Nocardia gardneri and three strains of N. corallina, were studied on cell-wall agar media prepared from five Gram-positive and three Gram-negative bacteria and from the yeast Candida pulcherrima. The three strains of Nocardia corallina showed no lytic activity on any of the cell-wall substrates. All of the actinomycetes tested were without activity on the Gram-negative cell-wall agar media. Most of the actinomycetes produced lysed zones on Gram-positive cell-wall agar and the greatest lytic activities were observed with Bacillus megaterium and Candida pulcherrima cell-wall substrates. Cytophaga johnsonae and two strains of Myxococcus fulvus were lytic on Candida pulcherrima cell-wall agar but no lysis occurred on the bacterial cell-wall agars.

Summary: Paramecium aurelia, var. 4, stock 51·7 (s) requires a steroid as a growth factor; β- and γ-sitosterol, fucosterol, brassicasterol, stigmastcrol and Δ4,22-stigmastadienone are active in supporting its growth. Esterification of the 3-hydroxyl group decreases the activity. The presence of more than one double bond in the ring system inactivates the molecule, as do the more drastic changes of the side chain, as found in diosgenin, digoxigenin, progesterone, estrone and methyl cholate. Oxidation of the ring system destroys activity. The specificity of these requirements suggests that the steroid functions as an essential metabolite for this organism.

Summary: A number of fungi isolated from soils under a variety of vegetational types was found to attack p-hydroxybenzaldehyde, ferulic acid, syringaldehyde and vanillin. These compounds were used as sole source of carbon by the organisms tested. By means of spectrochemical methods and paper chromatography it was shown that vanillin and ferulic acid were converted to vanillic acid before the breaking of the benzene ring, and syringaldehyde was converted to syringic acid. The bearing of these results on the breakdown of lignin in soil is discussed.

SUMMARY: In addition to structures already known, the trichomes of Caryophanon latum are shown to contain metabolically active cytoplasmic granules which agree with the definition proposed for bacterial mitochondria. Evidence is presented for some, at least quantitative, cytochemical differentiation among these granules.

SUMMARY: One hundred soils from various parts of the South Island of New Zealand were cultivated on an acid medium at 37°. Stockyard soils yielded most yeasts by this treatment, principally strains of Rhodotorula mucilaginosa and Candida parapsilosis. Few yeasts were isolated from rural soils, and very few from urban soils. Candida albicans was recovered from two soils, one from an urban area and one from a stockyard. Cryptococcus neoformans was not isolated.

The yeast flora which grew at room temperature (c . 18°) of 8 soils was also examined. One of these, a peat soil, yielded a pure culture of Candida brumptii. Species of Cryptococcus and Trichosporon were dominant in the other seven samples, and their yeast population as a whole was of colourless, capsulated, non-fermenting, starch synthesizing and nitrate utilizing organisms.

SUMMARY: Eight strains of bronchiseptica, six strains of parapertussis and fifteen strains of pertussis were examined for their minimal nutritional requirements in defined media. All strains showed an absolute requirement for nicotinic acid and no other vitamin was required for growth. Amino acids were essential for parapertussis and pertussis, but bronchiseptica would grow in either a mixture of amino acids, or lactate or citrate. Two old laboratory strains were exceptional in that they could utilize either glutamic acid, α-ketoglutaric acid, citrate, lactate, succinate or pyruvate. The amino acid requirements of the three species were relatively simple and showed some similarities. Bronchiseptica would grow in a mixture of glutamic acid, proline and leucine, while parapertussis required added cystine and methionine, and pertussis required in addition alanine, asparagine and serine. In simple amino acid mixtures glutamic acid was essential, but was replaceable by α-ketoglutaric acid. Nutritionally the species are very similar, but are quite different from the Haemophilus influenzae-parainfluenzae-canis, or the Brucella abortus-suis-melitensis groups of organisms. The nutritional evidence supports the already impressive evidence on other grounds that these three groups should be classified separately. If generic status is given to one group it should be given to all three. López (1952) has proposed a new genus Bordetella, consisting of the species B. pertussis, B. parapertussis and B. bronchiseptica, and this seems a reasonable solution to the present anomalous position. The three species can be differentiated by tests for inhibition. Thus B. bronchiseptica is the only species not inhibited by 20% citrate and B. pertussis the only species inhibited by colloidal copper sulphide.

SUMMARY: The bactericidal activity of streptomycin, isoniazid and combinations of streptomycin and isoniazid against tubercle bacilli growing in Tween albumin medium was measured with and without the addition of p-aminosalicylic acid (PAS). When the concentrations of these compounds were about 4 to 16 times their minimal inhibitory concentrations, PAS did not influence this activity, but it was slightly increased when the concentrations were 10 times higher (equal to peak serum concentrations in treated patients). Combinations of the low concentrations of PAS + streptomycin or PAS + isoniazid usually only delayed the emergence of drug-resistant bacilli, whereas combinations of the higher concentrations suppressed their growth.

SUMMARY: Selected species of yeasts, lactic acid bacteria and acetic acid bacteria were tested against twenty-six antibiotics and twenty other organic compounds during a search for methods for separating chosen members of the mixed microflora of apple juices. Some of these compounds were found to be specifically inhibitory against either yeasts or lactic acid bacteria, but few inhibited completely such acetic acid bacteria as were tested.

SUMMARY: Electron micrographs of organisms of the pleuropneumonia group are presented, which are consistent with a simple form of development that starts from a small dense body. This grows into a larger particle which may be round, oblong or filamentous in the liquid medium. Later, circumferential concentrations and central thinning occur. Eventually, the concentrations become the dense bodies from which new forms develop. A cell wall was not demonstrable.

Summary: The penicillin-binding component (PBC) of Staphylococcus aureus is rapidly inactivated by acid but is more stable at neutral or alkaline pH values. At 2° various preparations lost 25–50% activity overnight at the optimum pH. Cell-free preparations of PBC (penicillin-binding cell walls or ‘lipid particles’) showed an initial increase in the amount of PBC available to penicillin. PBC was heat-labile, being completely destroyed by 5 min. at 50°. The final amount of penicillin bound did not vary over the range pH 4·4–7·6, but the rate of binding was somewhat greater at the lower end of this range. No separation of PBC from lipid particles was achieved by several mild techniques. Organic solvents which did not remove lipid material from intact cells also failed to affect PBC; more drastic solvent procedures which were effective in removing lipid appeared to destroy PBC. Intact cells or lipid particles from a penicillin-resistant yeast did not bind penicillin.

Summary: A collection of 442 strains of lactobacilli, including representatives of all recognized species and 190 freshly isolated strains was studied serologically. Using sera prepared against some of these strains and crude HCl extracts, it was possible to classify 312 (70%) of these strains by precipitin tests into six groups and one subgroup. This classification was in agreement with one based on the physiological characteristics of the strains.

Summary: A study of 94 strains of lactobacilli was made. These were divided into three groups by ‘sugar’ fermentations and tolerance of sodium chloride and sodium tauroglycocholate. Strains of Lactobacillus acidophilus fermented amygdalin, cellobiose, salicin and sucrose, were variable in their action on dextrin and maltose, but grew in 2% sodium chloride or sodium tauroglycocholate. Strains of L. bulgaricus fermented none of these sugars and failed to grow in 2% sodium chloride or in 2% sodium tauroglycocholate. A third intermediate group failed to ferment amygdalin, cellobiose, salicin or sucrose, but all fermented dextrin and maltose and grew in 2% sodium chloride. They failed to grow in 2% sodium tauroglycocholate.

SUMMARY: The characteristics of 152 strains of lactobacilli were examined, and strains divided into three groups. Lactobacillus helveticus fermented inositol, sorbose, glycerol and rhamnose but not melibiose or raffinose, failed to grow in 4 % bile salt, but gave a positive Voges-Proskauer reaction and a rapid acid clot in Yeastrel glucose litmus milk (y.g.l.m.). L. casei would not ferment these sugars, nor tolerate 4 % bile salt, rarely gave a positive Voges-Proskauer reaction, but. produced a rapid acid clot in y.g.l.m. L. plantarum always fermented melibiose, usually raffinose and sometimes rhamnose, but did not ferment inositol, sorbose or glycerol. Strains of these species tolerated 4% bile salt but gave a negative Voges-Proskauer reaction and produced an acid clot in y.g.l.m. only slowly.

SUMMARY: The abomasums of three very young calves and two kids, of which all, save one suckled kid, had been fed on milk by bottle, were found to be supporting large populations of lactobacilli of both homo- and heterofermentative types. The heterofermentative organisms in every instance corresponded in fermentation reactions to Lactobacillus fermenti and was also found in one calf’s rumen. The single homofermentative strain isolated from a calf was very near to L. acidophilus in fermentation reactions. The kid abomasum homofermentative isolates all seemed to belong to a new and unusual variety of L. acidophilus (var. caprae). It was anxiolytic, insensitive to aureomycin, and hydrolysed aesculin.

The rumen and abomasum of the young calf contained an atypical variety of amylolytic streptococcus, differing from the typical Streptococcus bovis of the adult rumen in being non-haemolytic and in fermenting mannitol. The typical rumen S. bovis is sometimes truly iodophilic. These rumen and abomasum streptococci and lactobacilli are probably not introduced via the milk.

SUMMARY: Staphylococcus flavocyaneus, grown in chemically defined media, requires a purine; adenine, hypoxanthine, their respective ribosides and ribotides, 4-amino-5-imidazolecarboxamide or 4-amino-5-imidazolecarboxamidine were effective. Per mole, the ribotides (2′, 3′ or 5′) were most efficient. Growth with effective purines is inhibited by guanine and certain unnatural purines. Inhibition of growth by purines may involve two mechanisms: one concerned with the synthesis of unnatural nucleic acid; the other with a crippling of ribose metabolism.