摘要:

The intracellular concentrations of Na+, K+, and Cl−of an unidentified moderately halophilic bacterium were determined. When the cells were grown at a late linear growth phase in a chemically defined medium containing 1, 2, or 3 M NaCl and 5.5 mM K+, the intracellular Na+concentration (0.90–1.15 M) was independent of the Na+in the medium. The K+and Cl−concentrations were roughly on the same levels, respectively (0.67–0.89 M K+; 0.70–0.98 M Cl−). The Na+and K+per gram protein of the whole cells were 3.85 mmol and 2.96 mmol, respectively. When the cell envelope was incubated in a 2 M NaCl solution containing 5.5 mM K+and 0.1 mM Mg2+, the Na+concentration in the cell envelope was very high (6.49 mmol per gram protein) and K+was concentrated up to about 41 times of the external K+(0.36 mmol per gram protein). The high Na+content of the isolated cell envelope may serve as one of the keys to elucidating a role of Na+for the maintenance of the cell rigidity in this bacterium.

ISSN:0008-4166    

DOI:10.1139/m73-191

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The levels of the NADP-specific malic enzyme inFusarium oxysporumare controlled by both the carbon and nitrogen sources in which the cells are grown. The enzyme is not induced by malate; maximum activity is obtained when the mycelium is grown on sucrose or ethanol. With ammonium sulfate as the nitrogen source, one enzyme-activity peak is obtained by 40 h, while in the presence of potassium nitrate this peak is repressed, with a peak appearing at a later stage of growth. In ammonium nitrate, two enzyme-activity peaks are present, one corresponding to the peak present in ammonium sulfate and the other to the peak present in potassium nitrate grown cells.When the initial velocities are plotted against increasing malate concentration non-Michaelis–Menton kinetics are obtained. The double-reciprocal plots are biphasic andRsvalues of 161 are obtained. Hill plots prepared from initial velocity data show that at low malate concentration, the slope of the line is 0.87, and it decreases to 0.45 at 1.32 × 10−3 M malate. With increasing malate concentration the slope increased to a value of 1.0. It appears that this type of kinetic behavior is typical of a system in which there is negative cooperativity with respect to ligand binding with concurrent progressive substrate activation.

ISSN:0008-4166    

DOI:10.1139/m73-192

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The interaction ofPseudomonas aeruginosaandStaphylococcus aureusS6 was studied in two systems. In the first system, the two organisms were grown together in a single flask. Growth ofP.aeruginosawas unaffected, but growth ofS.aureuswas modified. After 24 h, 99.9% of the staphylococci population lost their salt tolerance when plated on media containing 7.5% sodium chloride, and enterotoxin B synthesis byS.aureuswas diminished. In the second growth system, pure cultures ofP.aeruginosaandS.aureuswere grown in membrane-type spinner flasks. The growth and salt tolerance ofS.aureuswas again affected, but to a lesser degree. Cultures ofS.aureusfrom these experiments recovered their salt tolerance in 6 h when transferred to fresh medium.Nutrient deficiency, lack of oxygen, or pigment production by the pseudomonads did not contribute significantly to loss of salt tolerance or inhibition of enterotoxin B synthesis, but a staphylolytic enzyme(s) isolated fromP.aeruginosawas shown to be responsible for the loss of these properties.

ISSN:0008-4166    

DOI:10.1139/m73-193

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Current methods of leptospiral taxonomy depend largely upon serological procedures, which are frequently erroneous.During the search for a more stable classification schema, the pyrolysis–gas–liquid chromatography (PGLC) method was tried and shown to be effective in differentiating common strains of leptospires.In this study, we made a preliminary pyrolysis–gas–liquid chromatography investigation on 16 coded samples of leptospires. Results correlated positively with serological classifications. An additional 12 authenticated strains were examined. These represented the most common and important serotypes. The 12 strains were grown on Ellinghausen's medium. They were isolated, washed, and killed before lyophilization. Each sample of dried cells was weighed and subjected to PGLC. Each strain gave its own individual profile of peaks ("fingerprint"). All strains could be differentiated and identified by their fingerprints.

ISSN:0008-4166    

DOI:10.1139/m73-194

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The bovine alveolar macrophage (BAM) was isolated in large numbers from lung washings and could be cultivated in vitro up to 63 days in medium 199, 20% foetal calf serum (FCS). Freshly isolated cells examined by electron microscopy (EM) were similar to those of the mouse. Cultured BAM prepared for EM were larger than fresh cells and contained discrete packets of homogenous material, possibly lipid. The BAM phagocytosedStaphylococcus aureus(FDA209P, type 42D) but the percentage of cells phagocytosing was reduced when FCS was not present, when cells were infected for 30 min compared with 45 min and when 2 × 107 CFU/ml compared with 2 × 108 CFU/ml were used to infect the cells.

ISSN:0008-4166    

DOI:10.1139/m73-195

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Lipopolysaccharides isolated from the marine bacteriumVibrio marinusstrain PS-207 were found to be similar to the lipopolysaccharides of R mutants of enteric organisms, with respect to extraction characteristics, percentage of lipid A (61%), and sugars of the polysaccharide side chain (glucose and heptose). A high ratio (2:1) of phosphate to amino sugar was found in the lipid A. Hydroxy fatty acids constituted only 14% of the total fatty acids of the lipid A fraction, whereas branched and straight-chain fatty acids were present in greater abundance. The major envelope proteins ofV.marinusstrain PS-207 fell into three molecular weight classes determined by SDS gel electrophoresis. Numerous protein species were observed in urea – acetic polyacrylamide gel electrophoresis preparations.

ISSN:0008-4166    

DOI:10.1139/m73-196

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The influence of nitrogen source on the formation of the extracellular acid protease and acid ribonuclease in shake cultures of the moldPenicillium janthinellumhas been studied. It is observed that there is a long delay in the formation of the enzymes when nitrate is the sole source of nitrogen, but they are formed much earlier on other nitrogen sources such as ammonium salts, urea, or bacto-peptone. They are also formed earlier when nitrate is partially replaced by an ammonium salt. Small amounts of nitrite and hydroxylamine inhibit the formation of the enzymes when the mold is grown on ammonium lactate. When the mold is grown on nitrate, the culture filtrates contain inhibitory amounts of nitrite and hydroxylamine. The results indicate that the delayed formation of the enzymes in nitrate medium may be due to the formation of nitrite and hydroxylamine, which are inhibitory. The activities of the two enzymes are not inhibited by nitrite or hydroxylamine, in vitro. Prolonged preincubation of the enzymes with nitrite or hydroxylamine also does not affect the enzyme activities, indicating that it is the formation of the enzymes that is affected.

ISSN:0008-4166    

DOI:10.1139/m73-197

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Alkaline phosphatase and a subunit form of the enzyme have been isolated fromPseudomonas aeruginosa. The enzyme is pure as judged by molecular-sieve chromatography, sodium dodecyl gel electrophoresis, and ultracentrifugation. The enzyme possesses the following properties: (a) existence of three forms: monomer mol. wt. 39 000, dimer mol. wt. 68 000, and tetramer mol. wt. 139 000; (b) pH optimum 10.5; (c) Michaelis constantKm = 6.6 × 10−5 Mp-nitrophenyl phosphate; and (d) energy of activation 5647 cal/mol. Amino acid analysis indicates a protein that is hydrophobic. Its physical behavior in solution supports this conclusion. These results explain the observed association of alkaline phosphatase and lipopolysaccharide and substantiate the current theory that the alkaline phosphatase ofP.aeruginosais bound to the outer cell wall in vivo.

ISSN:0008-4166    

DOI:10.1139/m73-198

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

A pigment absorbing at 503 nm (P503) was observed in the difference spectra of several strains of microorganisms. The pigment was present in most facultative anaerobes and absent from many but not all of the aerobes examined. P503 is probably not a component of the normal oxygen-linked electron transport chain since the pigment was present in both respiratory sufficient (ρ+) and deficient (ρ−) strains ofSaccharomyces cerevisiae. There was no apparent correlation between P503 and either the cytochromes or any known metabolic cellular activities. However, the widespread occurrence of P503 in microorganisms suggests that it is of functional significance.

ISSN:0008-4166    

DOI:10.1139/m73-199

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The pigment (believed to be a tetrahydroporphyin) which appears, transiently, at 503 nm (P503) in the difference spectrum of intact cells ofEscherichia coliB did not accumulate in cultures grown in medium supplemented withL-methionine. Accumulation of P503 was not prevented by structural analogues ofL-methionine, nor by a mixture of natural amino acids excludingL-methionine. A methionine-requiring mutant ofE.coliK-12 lacked P503 when grown in the presence ofL-methionine, but P503 was present ifD,L-ethionine was substituted forL-methionine in the growth medium. WhenL-methionine was added to air-oxidized cells which had been grown on minimal (glucose–salts) medium, the spectrum of P503 was produced specifically and rapidly. This effect ofL-methionine in non-proliferating cells together with the inhibition byL-methionine of P503 accumulation in growing cultures may result from the stimulation of coproporphyrinogenase by methionine. The data indicate that P503 is an early intermediate in the conversion of coproporphyrinogen III to protoporphyrin IX rather than an intermediate in the porphyrin synthesis "by-pass' to coproporphyrin III.

ISSN:0008-4166    

DOI:10.1139/m73-200

出版商:NRC Research Press    

年代:1973

数据来源: NRC