摘要:

A comparison of 20 media based on degraded milk protein or tryptone, yeast extract, and sodium acetate snowed that various new formulae were superior to standard media for enumeration of cytophagas from aquatic habitats, for their isolation, and for maximum expression of the spreading characteristic. The use of 0.1 μliter/liter Tween 20 in dilution blanks increased counts of cytophagas up to threefold, but incorporation of Tween 20 into the plating agar had no significant effect on the numbers recovered. Sodium lauryl sulfate (S.L.S.) was examined as a possible screening agent for identification of cytophagas. A concentration of 0.1% S.L.S. inhibited the growth of 97% of the 66 cytophagas tested, but more than 80% of the other 41 organisms tested were also affected. However, 91% of the cytophagas were sensitive to S.L.S.andshowed proteolysis on skim acetate medium compared to 53% of the Flavo-bacteria and 50% of the other organisms tested. None of the third group of organisms could be confused morphologically with the cytophaga group; thus it is suggested that S.L.S. susceptibility performed on skim acetate medium could be a useful screening test for cytophagas.

ISSN:0008-4166    

DOI:10.1139/m72-299

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Bdellovibrio bacteriovorus, strain 6-5-S, multiplied in the presence of washed suspensions ofEscherichia coli,Spirillum serpensVHL, andBacillus megateriumwhich had been autoclaved for 5 min at 121C. No intracellular life cycle was observed.Bdellovibrio bacteriovoruswas also able to multiply in an extract from autoclavedE.colicells after the cells had been removed by centrifugation. Growth of the parasite was dependent upon the addition of Ca2+and Mg2+to the buffer solution. The growth rate and yield ofB.bacteriovoruson autoclaved cells were not affected by the initial concentration of the parasite. During multiplication ofB.bacteriovorus, amino acids, amino sugars, and reducing sugars were released into the culture fluid.

ISSN:0008-4166    

DOI:10.1139/m72-300

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Electron microscopy of the two species ofFilobasidiumshow representative basidiomycete dolipores, but in which the pore-occluding material, instead of being a homogenous, electropaque, dome-shaped structure, is a flattened plate with dark edges and a lighter center. Parenthesomes inF.capsuligenumare represented by clusters of cone-shaped vesicles that appear to be anchored by microfilaments that pass into the pore-occluding plate. Parenthesomes are absent inF.floriformebut occasionally vesiculate endoplasmic reticulum (ER) is seen in the pore region. Other cell structures are also illustrated.

ISSN:0008-4166    

DOI:10.1139/m72-301

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The intracellular enzyme,L-asparaginase, from aerobically grownErwinia aroideaeNRRL B-138 has been purified and some of its properties studied. Sonic treatment permitted recovery of 95% ofL-asparaginase from cells. The crude cell lysate was purified 167-fold by means of ammonium sulfate fractionation and column chromatography on hydroxylapatite–cellulose, and DEAE–Sephadex. The specific activity of the most active fraction ofL-asparaginase is 256 IU/mg protein. The enzyme has a broad pH activity profile with maximum at pH 9.0–9.5. The optimum temperature for enzyme reaction was determined to be 41 °C. The apparent activation energy is 11 000 cal/mole. The molecular weight ofL-asparaginase was estimated by gel filtration to be 108 000.

ISSN:0008-4166    

DOI:10.1139/m72-302

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Development of sporangia inPhytophthora palmivoraButler consists of two main stages. The first involves expansion of the sporangial initial to about the size of the mature sporangium, whereas the second is characterized by the differentiation of the expanded vesicle to the mature sporangium. Differentiation includes basal plug formation, secondary sporangial wall thickening, and apical papilla formation.Expansion of the sporangial initial appears to be mainly the result of cytoplasmic inflow from the mycelial mat coupled with surface growth of the vesicle wall. Basal plug formation terminates the phase of expansion. The process of plug formation involves deposition of wall-like material at the base of the expanded vesicle. The depositions, which grow from the periphery towards the center of the sporangiophore, are at first rather irregular in shape but eventually lead to complete occlusion, thus separating the immature sporangium from the sporangiophore. Sporangial wall thickening starts at the basal plug and progresses towards the developing apical papilla. Papilla formation is initiated by an apical bulge of the immature sporangium. The cytoplasm within the bulge is specialized and characterized mainly by populations of small (50–100 nm) and large (about 250 nm) vesicles, which appear to be involved in papilla formation. Papilla deposition resembles hyphal tip growth in the absence of cell expansion.

ISSN:0008-4166    

DOI:10.1139/m72-303

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Cultures ofParamecium caudatumorP.multimicronucleatumincubated with aflatoxin were killed when irradiated with light of wavelength 366 nm. Cultures incubated either with aflatoxin in the dark or in the light with no aflatoxin were not affected.

ISSN:0008-4166    

DOI:10.1139/m72-304

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Protoplasts ofEntomophthoraspp. were satisfactorily preserved in liquid nitrogen after controlled-rate cooling to −40 °C. 5% Dimethyl sulfoxide was the preferred cryoprotectant.

ISSN:0008-4166    

DOI:10.1139/m72-305

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The formation in culture of dimethyl- and diethyl-nitrosamine from sodium nitrite and secondary amines was brought about byStreptococcusspecies, but not by members of several other genera tested. This formation appears to be non-enzymic, pH dependent, and may be catalyzed by one or more bacterial metabolic products.

ISSN:0008-4166    

DOI:10.1139/m72-306

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Virus-like particles of 350 Å have been observed intracellularly in a strain ofM.hominis. This appears to be the first example of such particles within cells of the order Mycoplasmatales.

ISSN:0008-4166    

DOI:10.1139/m72-307

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Several strains of extremely halophilic bacteria produced pyruvate when grown in the presence of glucose. One, M6, formed pyruvate and acetate from glucose, galactose, lactose, fructose, and sucrose. The greatest accumulation of these acids occurred when cells were grown with glucose; in the presence of galactose or lactose, the appearance of acetate and pyruvate was transitory. Glucose and galactose were oxidized by resting cells. Oxygen consumption with glucose as the substrate was 18% of the theoretical amount required for complete oxidation, whereas with galactose, it was 83% of theoretical. Galactose-grown cells or cells grown in the absence of carbohydrates also oxidized pyruvate and acetate; the oxidation of these acids by glucose-grown cells was negligible. These data are consistent with either of the following hypotheses: glucose, or one of its metabolites, interferes with the metabolism of acetate, or glucose and galactose are metabolized by different pathways.

ISSN:0008-4166    

DOI:10.1139/m72-308

出版商:NRC Research Press    

年代:1972

数据来源: NRC