- Volume 52, Issue 3, 1968

SUMMARY: A number of non-marine Oomycetes and a marine-isolated Pythium culture were lysed in natural sea water by marine micro-organisms. A relationship was observed between the rate and extent of lysis and the size of the marine microbial population. Microscopic observations and the accumulation of reducing sugars indicated that extracellular cell wall-lysing enzymes were responsible. Pure cultures of lytic bacteria isolated from the sea yielded data similar to those obtained in natural sea water. The importance of the lytic phenomenon in the determination of the marine mycoflora is discussed.

SUMMARY: The study of ultrathin sections of Thiobacillus novellus has shown that it has a structure similar to that of T. thiooxidans and other Gram-negative bacteria. The cell wall showed a multilayered structure and varied in thickness between 250 and 350 Å. The cytoplasmic membrane and 70 Å thick. On certain media a capsule was formed. The cytoplasm contained ribosomes and polymetaphosphate granules. The structure of the nuclear material was similar to that observed in other bacteria.

SUMMARY: The bacterial flora on the skin of plaice (Kareius bicoloratus) caught in coastal regions of Japan was composed of bacterial groups heterogenous to the concentration of salt in their growth behaviour. Each bacterial group had a different minimum and/or maximum salt concentration for growth, and different groups were selected by media with different salt concentration. In the media based on two complex salt solutions, including an artificial sea water, the maximum bacterial counts were obtained at concentrations corresponding to about 25% dilution of sea water. During the storage of fish at 24° and 2°, bacteria which required higher salt concentrations for growth increased faster than that of non-halophilic bacteria. The microflora of the digestive tract of the fish was composed almost exclusively of halophilic vibrios.

SUMMARY: A medium for the isolation of heterotrophic aerobic bacteria from marine fish has been developed. The medium contains inorganic ions with a total concentration equal to about half that of sea water. The ionic ratio of sodium and potassium in the medium is nearly 1:1, and the concentration of the organic nutrients is higher than in media that have been generally used for the isolation of bacteria from sea water.

SUMMARY: The aerobic bacterial flora of the digestive tract of jackmackerel (Trachurus japonicus) was found to be composed almost exclusively of species of the genus Vibrio. Comparison of the flora of the stomachs with that of the intestines of these fish indicated that only vibrios were found in the intestines.

SUMMARY: Staphylococcus aureus (oxford) when grown in the presence of glycerol increased its cellular lipid content to the extent of 18% calculated on a cell dry-weight basis. When challenged by a homologous series of 4-n-alkyl phenols (H- to C6H13-) an increase in resistance was noted with the glycerol grown (fattened) cocci after the 4-n-butyl (C4H9-) phenol. This phenomenon was investigated by means of electrophoresis of single cocci, the measurement of drug uptake, and the effect on leakage of cytoplasmic constituents as well as by the assessment of minimum inhibitory concentrations. Electron micrographs of thin sections of normal and fattened cocci were also examined.

SUMMARY: Growth of Bacillus subtilis and of Escherichia coli following treatment with oxygen at 10 atmospheres for 18 hr was synchronous. Treatment at lower pressures resulted in a much lower degree of synchrony. After exposure to high-pressure oxygen to induce synchronous growth of B. subtilis the resistance of various stages of the cell cycle to further treatment with oxygen at 10 atm. was studied. Maximum resistance occurred immediately following division of the bacilli and then fell to a low value. The region of maximum resistance in B. subtilis compared fairly closely with the time of maximum catalase activity.

SUMMARY: An ecological survey of the microflora of an upland moorland soil and the underlying shale was made over a 2-year period. Samples were taken at different depths of about 5, 20 and 40 cm. in the soil, and from the underlying shale band in a cave system nearby, and the average total counts of bacteria and fungi were 35 × 106, 3 × 106 and 1 × 106 per g. dry wt respectively. Hydrocarbon-oxidizing organisms occurred in all the samples. The numbers and activity of these organisms were determined in a variety of ways and finally expressed as a function of the total population of each sample. A significantly higher proportion of the population of the 20 cm. soil sample was able to utilize hydrocarbons as sole energy and carbon source, than of any of the other samples. When hydrocarbons were added there was a stimulation in respiration of all samples. Maximum stimulation of respiration occurred in the 20 cm. soil sample. The E h of the 20 cm. soil sample was lower than in any other sample, it also contained a higher level of lipid and hydrocarbons. It is suggested that the higher level of hydrocarbon oxidation in the 20 cm. soil sample is due to the accumulation of hydrocarbons with a resulting adaptation of the microbial populations. More organisms were able to oxidize the longer chain n-aliphatic hydrocarbons than the short chain n-aliphatics, aromatic and alicyclic hydrocarbons. A list of the genera, including fungi, responsible for the oxidation of each hydrocarbon is given: the fungi play an important role in the hydrocarbon-oxidizing activity of each sample.

SUMMARY: The presence or absence of regulatory control mechanisms has been studied for the enzymes 6-phosphogluconate dehydrogenase, glucose 6-phosphate dehydrogenase and hexokinase in Bacillus subtilis. The cellular levels of these enzymes have been investigated during steady exponential growth in various media and following growth shifts. Comparison has been made of the behaviour of these enzymes with that of β-galactosidase in a strain of Escherichia coli in which the regulator and operator genes are deleted. Criteria for recognizing truly constitutive enzymes are discussed, and it is tentatively concluded that while the synthesis of the dehydrogenases is controlled, that of hexokinase is probably constitutive.

SUMMARY: The ability of the L-form of two strains of group A streptococci to pass filters was assessed by several methods. From a comparison of the results, and taking into account the plasticity of the L elements, it is concluded that the size of the reproductive elements of the L-form of the group A streptococcal strains investigated probably lies between 0·45 μ and 0·65 μ. The passage of the elements through filters with pores measuring 0·45 μ or less in diameter may be explained by the ease with which the elements are deformed. The variation between the results obtained with different filtration methods can be attributed to differences in experimental conditions which affect the degree of deformation.

SUMMARY: Slide cultures consisting of small agar blocks were inoculated with the L-forms of two group A streptococci strains gl-8 and aed grown in broth. The size of the L-form elements was measured on photographs taken immediately after inoculation of the slide cultures. The diameter of the elements varied between 0·2 and 3·0 μ. The frequency distribution of the diameters has a bimodal form. This bimodality probably represents the size distribution of two classes of L-form elements which can arbitrarily be divided at the diameter of 0·7 μ.

The reproductive elements of the streptococcal L-forms were found, with a few exceptions, to have a minimal diameter of 0·7 μ (average diameter 1·4 and 1·2 μ, respectively; standard deviation 0·3 μ).

Slide culture experiments with concentrated filtrates of 0·45 filters showed that the reproductive elements present in the filtrates ranged in size from 0·8 to 1·7 μ with an average diameter of 1·2 μ (standard deviation 0·2 μ). The filterability of the streptococcal L-form might therefore be mainly due to the plasticity of the L-form elements.

SUMMARY: The system for transporting arginine into Neurospora conidia is described and shown to be consistent with the permease concept. The arginine system is shown to be separate from that which transports the aromatic and branched-chain neutral amino acids. Metabolic energy is necessary to achieve a concentration of arginine in the conidia higher than the external medium but not to maintain this concentration differential. A canavanine resistant mutant is shown to transport the basic amino acids at a reduced rate but the mutant transports other amino acids at the normal rate.

SUMMARY: The unnatural glucose analogue 2-deoxy-d-glucose was found to be fungistatic rather than fungicidal for a laboratory wild-type strain of the Basidio-mycete Coprinus lagopus; the analogue was not used as a carbon+energy source. Extension-growth rate of the organism was profoundly affected by the presence of 2-deoxyglucose; but although this growth could be prevented completely the inhibition was readily annulled, either by the addition of an excess of the normal substrate or by transfer to normal media. The extent of the inhibition observed depended not only on the ratio of normal hexose to analogue, but also on the identity of the normal hexose in the medium. Coprinus lagopus was at least 100 times more sensitive to the analogue when fructose was present than with glucose. This extreme sensitivity differential was also observed in the effect of 2-deoxyglucose on oxygen uptake by spore suspensions: inhibition of O2 uptake occurred, and was about 100 times greater with fructose than with glucose.

SUMMARY: Forty-two strains of Corynebacterium acnes were compared with 20 strains of staphylococci and 10 of lipophilic diphtheroids for their lipolytic action on 14 substrates and for Tween 80 hydrolysis. All strains were isolated from normal human skin. One lipophilic diphtheroid and 33 C. acnes strains hydrolysed tributyrin. Forty-nine bacillary strains hydrolysed Tween 80. None of the other substrates was degraded. C. xerosis atcc 373 and Propioni-bacterium acnes atcc 11828 acted on tributyrin. P. acnes also hydrolysed Tween 80. The staphylococci did not act on Tween 80 but attacked tributyrin, triolein, trilinolenin, trilinolein and oil emulsions. Some cocci acted on tricaprylin, tricaprin and trilaurin; no lipolysis by this group was observed of trimyristin, tripalmitin or tristearin. Pancreatic lipase, tested by the penicylinder diffusion method for comparison, was active on the same substrates, as were the cocci. The addition of glucose, lactate and urea to media did not inhibit lipolysis by the cocci. Sodium oleate inhibited pancreatic lipase action on triolein and cottonseed oil but not on the hydrolysis of tributyrin. Coccal lipase action was not inhibited by oleate. All 74 test strains were uniformly inhibited by neomycin 5–10 μg./ml. Gram-positive cocci rather than C. acnes appear primarily responsible for bacterial lipase activity on human skin.

SUMMARY: Water-insoluble complexes of ganglioside with cerebroside fixed tetanus toxin at low concentrations (a few LD 50/ml.) of toxin. A complex containing 25% ganglioside with cerebroside was 50 times better at fixing toxin than complexes containing either 2% or 50% ganglioside. A complex containing 25% of a mixture of the gangliosides Giii and Giv was 12 times better at fixing toxin than a similar complex with gangliosides Gi and GII. Complexes of ganglioside with sphingomyelin and lecithin fixed toxin to a slight extent, while complexes with tripalmitin and cholesterol did not fix toxin. The complex of cerebroside and ganglioside, containing 25% ganglioside, did not fix strychnine, serotonin, botulinum toxin or plasma albumin.

SUMMARY: Extracts (ultrasonic treatment) of Clostridium sordellii contained a lysolecithinase, which was activated by ether, calcium ions and ammonium sulphate and inhibited by EDTA, magnesium and manganese. The enzyme was not responsible for the lethality, oedema-producing or haemorrhagic actions of extracts of the organism.

SUMMARY: The ‘spray’ mutant of Neurospora crassa responded differently from the wild type when grown in conidiogenic (C) and mycelial (M) media. In both media spray produced an unpigmented non-conidiating form of growth, whereas the wild type formed pure mycelial cultures on M-medium and conidiating growth on C medium. Analysis of the fine structure of spray revealed that the modal width of mitochondria of C- and M-media grown cultures was virtually identical. Since it is known that C-cultures of wild-type N. crassa possess swollen mitochondria, a relationship was suggested between mitochondrial swelling and the metabolic mechanisms which govern conidial differentiation. Spray also varied from the wild type in cell-wall thickness. Intraconidial conidia were observed in the spray mutant. These internal conidia always contained normal cytoplasm, while that of the host cell consisted of degenerate components. Intra-conidial conidia might arise as a result of proliferation of the septal wall.

SUMMARY: The silver methanamine technique was used to locate mucopolysaccharides in ultrathin sections of bacteria. Polysaccharides were located along the cell wall and developing cross-walls in young vegetative forms and along the developing cortex in sporulating bacilli. The results are discussed in relation to morphological and chemical studies.