摘要:

The electrophoretic mobilities of non-specific esterases in vertical polyacrylamide slab gels were determined for 184 strains of staphylococci, representing a total of 18 proposed species and subspecies. Markedly uniform esterase patterns were seen within species demonstrating a high degree of human host specificity, while those species demonstrating a wide host range were polytypic and often showed considerable polymorphism. The unique banding patterns found in several species indicate that this technique may serve as a valuable aid to existing taxonomic schemes. Starch gel electrophoresis of representative strains usually produced sharper esterase bands than were found with polyacrylamide electrophoresis. However, the additional molecular-sieving effect produced by the polyacrylamide gels differentiated esterases to a greater extent.

ISSN:0008-4166    

DOI:10.1139/m76-113

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

An unidentified halophile isolated from plates of a complex agar medium containing 4.25 MNaCl showed optimum growth in broths containing 0.5–1.0 MNaCl but exhibited a wide range of growth from 0.045–4.5 M. The organism can be classified as a facultative halophile with wide salt tolerance. Logarithmic phase cells grown in media containing 0.5 MNaCl were rod-shaped in long chains which changed to smaller, single, or paired cells in stationary growth. The internal Na+and K+concentrations were 0.05 Mand 0.34 Mfor logarithmic phase cells and 0.29 and 0.32 Mfor stationary phase cells. In 4.3 MNaCl media the cells were rod-shaped throughout the growth cycle, occurring primarily in pairs. The internal Na+and K+concentrations in cells in logarithmic phase growth were 0.62 Mand 0.58 Mwhile in stationary phase growth these values were 1.01 Mand 0.66 Mrespectively. In contrast, logarithmic phase cells of the extreme halophileHalobacterium cutirubrumhad internal Na+and K+concentrations of 0.80 Mand 5.32 Mwhen grown in 3.3 MNaCl. The internal Na+and K+concentrations, therefore, in the unidentified halophile do not resemble those found inH.cutirubrumbut are much closer to those present inEscherichia coli.

ISSN:0008-4166    

DOI:10.1139/m76-114

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Melanin biosynthesis inVerticillium dahliaeKleb. was studied with mutants deficient for normal black melanin or for production of microsclerotia. Seven genetically different mutants had apparent blocks in melanin biosynthesis. Four mutants (brm-Ito -4) produced brown microsclerotia and extruded pigments into media; three (alm-1to -3) produced albino microsclerotia. Other mutants produced no microsclerotia (nms) or had greatly reduced numbers of microsclerotia (rms). Mutationalm-1was due to a single recessive gene; the other melanin-deficient characters were recessive but their genetic bases were not determined. Cultures of the brown mutantsbrm-1and -3extruded and accumulated a metabolite that blackened the albino microsclerotia ofalm-1to -3. The metabolite was identified as (+)-scytalone (3, 4-dihydro-3, 6, 8-trihydroxy-1(2H)naphthalenone). Pigment formed byalm-1microsclerotia from (+)-scytalone had chemical and physical properties identical with those of melanin in the wild-type fungus. (+)-Scytalone was produced and converted to melanin by microsclerotia but not by conidia or hyphae. Conversion of (+)-scytalone to melanin appeared to involve two or more enzymes and probably involved conversions to 1, 3, 8-trihydroxynaphthalene and 1, 8-dihydroxynaphthalene. Albino mutants ofThielaviopsis basicola,Drechslera sorokiniana,Pleospora infectoria(Alternaria),Ulocladiumsp., andCurvulariasp. also converted scytalone to pigments indistinguishable from the melanins found in their respective wild types. Scytalone melanin may be common in fungi with dark brown or black pigments.

ISSN:0008-4166    

DOI:10.1139/m76-115

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

In the present studyPseudomonas aeruginosalipopolysaccharide (LPS) exhibited the following endotoxin properties: (1) toxicity for mice; (2) gelation of theLimuluslysate; (3) induction of a localized Shwartzman reaction in the skin of rabbits, and (4) anticomplementary activity.Differences in LPS toxicity as measured with the rat liver mitochondrial assay system were found to be related to the nature of the bacterial growth media, the functional integrity of mitochondria, and the time and temperature of mitochondrial assay. The significance of these findings toP.aeruginosainfections is discussed, and it is concluded that LPS is a factor of importance.

ISSN:0008-4166    

DOI:10.1139/m76-116

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The levels of phosphofructokinase (EC 2.7.1.11) and mannitol-1-phosphate dehydrogenase (EC 1.1.1.17) have been determined in a number ofMucorandPenicilliumspecies. Mannitol-1-phosphate dehydrogenase was found in only one species of mucor,Mucor rouxii, and this with a specific activity much lower than that found inPenicilliumspecies. All of the fungi tested in the Ascomycetes class exhibited mannitol-1-phosphate dehydrogenase activity. Interference from both mannitol-1-phosphate dehydrogenase and NADH oxidase (EC 1.6.99.5) caused some difficulty initially in detecting phosphofructokinase inPenicilliumspecies; thePenicilliumphosphofructokinase is very unstable.Penicillium notatumaccumulates mannitol intracellularly; detection of mannitol-1-phosphate dehydrogenase and mannitol-1-phosphatase (EC 3.1.3.22) activity in cell-free extracts indicates that the mannitol is formed from glucose via fructose-6-phosphate and mannitol-1-phosphate; no direct reduction of fructose to mannitol could be detected. The mannitol-1-phosphate dehydrogenase was specific for mannitol-1-phosphate and fructose-6-phosphate; NADP+(H) could not replace NAD+(H). The phosphatase (EC 3.1.3.22) exhibited a distinct preference for mannitol-1-phosphate as substrate; all other substrates tested exhibited less than 25% of the activity observed with mannitol-1-phosphate.

ISSN:0008-4166    

DOI:10.1139/m76-117

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Several strains of thermophilic aerobic spore-forming bacilli synthesize β-galactosidase (EC 3.2.1.23) constitutively. The constitutivity is apparently not the result of a temperature-sensitive repressor. The β-galactosidase from one strain, investigated in cell-free extracts, has a pH optimum between 6.0 and 6.4 and a very sharp pH dependence on the acid side of its optimum. The optimum temperature for this enzyme is 65 °C and the Arrhenius activation energy is about 24 kcal/mol below 47 °C and 16 kcal/mol above that temperature. At 55 °C theKmis 0.11 Mfor lactose and 9.8 × 10−3 Mforo-nitrophenyl-β-D-galactopyranoside. The enzyme is strongly product-inhibited by galactose (Ki = 2.5 × 10−3 M). It is relatively stable at 50 °C, losing only half of its activity after 20 days at this temperature. At 60 °C more than 60% of the activity is lost in 10 min. However, the enzyme is protected somewhat against thermal inactivation by protein, and in the presence of 4 mg/ml of bovine serum albumin the enzyme is only 18% inactivated in 10 min at 60 °C. Its molecular weight, estimated by disc gel electrophoresis, is 215 000.

ISSN:0008-4166    

DOI:10.1139/m76-118

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

In an attempt to throw further light on the relationship of R17 phage RNA and A-protein during the early stages of infection, studies were carried out to determine the effect of ribonuclease (ribonuclease 1, EC 3.1.4.22) on the ability of these two phage components to penetrate into host bacteria. It was found that the penetration of phage RNA is affected by ribonuclease concentrations as low as 0.1 μg/ml, while the penetration of phage A-protein was unaffected by ribonuclease concentrations as high as 20 μg/ml. In addition, it was found that a significant fraction of the phage RNA is resistant to the ribonuclease effect. This RNase-resistant portion of the phage population increased with increasing phage concentrations, and gave rise to the penetration of intact, 28S RNA molecules that produced the expected number of infectious centers. These findings are discussed in terms of a model for phage RNA injection in which the A-protein functions both as an attachment organelle and a pilot protein that guides the RNA from the capsid to the exterior surface of the F pilus, and thence into the host bacterium.

ISSN:0008-4166    

DOI:10.1139/m76-119

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Experimental infection of mice withNeisseria meningitidiswas established by the injection of the bacteria suspended in solutions of various iron compounds. The progressive and fatal infection caused by otherwise non-lethal doses of organisms was produced in these mice after prior injection with ferrous sulphate or concomitant injection with iron sorbitol citrate or iron dextran. Reduction in LD50to levels at least comparable to those obtained in the mucin challenge system was achieved; in some serogroups ofN.meningitidisthe LD50was decreased more than a million fold. The results suggest that iron, which is a component of hog gastric mucin, is a factor involved in the establishment of meningococcal infection in mice. Use of iron compounds as injection medium offers a more advantageous system than mucin, since controlled administration of chemically defined substances occurs.

ISSN:0008-4166    

DOI:10.1139/m76-120

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Growth of five strains of psychrophilic bacteria (fourArthrobacterand onePseudomonas) isolated from glacial deposits was studied at different temperatures. Three strains were facultative psychrophiles, having an optimum temperature for growth at about 25–28 °C and a maximum at about 32–34 °C. The twoArthrobacter glacialisstrains were found to be obligate psychrophiles with an optimum at 13–15 °C and a maximum at 18 °C. Arrhenius plots showed thatA.glacialiscould compete with the facultative psychrophilic bacteria only at 0 °C, that is, the temperature of its natural environment. The psychrophilicArthrobacterspecies studied here are more resistant to thermal stress than are marine psychrophilic bacteria.ForArthrobacter, in contrast toPseudomonas, temperatures above the optimum induced formation of filaments and abnormal cells. The culture turbidity increased 10 to 30 times, whereas viable count tended to decrease. The thermal block seems to prevent cell wall synthesis and septation, but at a different step for each species.

ISSN:0008-4166    

DOI:10.1139/m76-121

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

About 25Streptococcus bovisbacteriophages were isolated from abattoir wastes, bovine rumen fluid, and lysogenic strains ofS.bovis. Eight phages were selected and characterized by morphology, stability, rate of adsorption, single-step growth curve, serum neutralization, and antigenic relationship. Two distinct morphological phage types were found, one of which has not been previously reported for group D streptococci.

ISSN:0008-4166    

DOI:10.1139/m76-122

出版商:NRC Research Press    

年代:1976

数据来源: NRC