摘要:

The effects of a variety of nitrogen compounds, mainly amino acids, on oxytetracycline formation and growth were studied inStreptomyces rimosus. Of the amino acids, N-acetyl-DL-alanine and N-acetylglycine supported the highest antibiotic yields. No correlation was evident between the capacity of an amino acid to support growth or stimulate antibiotic formation. Likewise, other adjuncts that stimulated growth did not necessarily enhance antibiotic production. Nutritional differences based on amino acid utilization and antibiotic synthesis using alanine and aspartic acid isomers existed among different strains ofS.rimosus. In addition, a synthetic medium was developed that gives excellent antibiotic production though organic nitrogen is omitted.

ISSN:0008-4166    

DOI:10.1139/m64-052

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

ADebaryomyces kloeckeristrain from a Macquarie Island soil proved to be parathiotrophic, unable to satisfy its sulphur requirements from inorganic sources; certain sulphur amino acids were necessary. By contrast, inorganic sulphate and thiosulphate, but not dithionate, sulphide, or colloidal sulphur, were effective sulphur sources for a second (euthiotrophic) strain.Both strains behaved identically towards various organic sulphur compounds tested as sole sulphur sources. Growth was supported byL-cysteine,L-cystine,DL-homocysteine,DL-cystathionine,L-cystathionine,DL-lanthionine,D- andL-methionine, methionine sulphoxide, methylDL-methionine sulphonium chloride, and thiazolidine-4-carboxylic acid. Ineffective were methanethiol, thioglycollate, reduced glutathione,DL-homocystine, cysteic acid, taurine, methionine sulphone, djenkolic acid, thiamine, thiazole, thioacetamide, and thiourea. Biotin, though essential for both strains, was ineffective as a sole sulphur source.The parathiotrophic strain may be a mutant lacking an enzyme at some step in conversion of sulphate to cysteine. Because of difficulties with unstable intermediate compounds, the course of cysteine biosynthesis from sulphate inD.kloeckericould not be defined from nutritional data alone, nor could one tell which of the sequential steps is blocked in the parathiotroph.

ISSN:0008-4166    

DOI:10.1139/m64-053

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Some aspects are described of the kinetics of the growth ofGibberella fujikuroiin nitrogen-limited media containing either ammonium nitrate, ammonium acetate, ammonium tartrate, urea, or glycine. Also varied were inoculum size, agitation rate, pH, and initial concentrations of glucose and nitrogen source. The significance of kinetic parameters used in this, and published studies, is discussed.A lag phase was only found on ammonium acetate media or when high concentrations of glucose were present. Early growth was exponential on all nitrogen sources. On ammonium acetate the specific growth rate decreased at a dry weight of ca. 1 mg/g WS (Whole unfiltered Sample). On ammonium nitrate, early exponential growth utilized more NH3-nitrogen than NO3-nitrogen with a concomitant decrease in pH. In the range pH 3.0–2.8 NH3-nitrogen uptake and dry weight increase ceased, but NO3-nitrogen uptake continued, and the pH increased until growth and NH3-nitrogen uptake restarted. This pattern could be repeated. Finally, exponential growth was resumed at a low specific growth rate. On glycine, urea, and ammonium tartrate media, exponential growth continued to a dry weight of about 7 mg/g WS. During this period the uptakes relative to dry weight (contributions) of glucose, nitrogen, phosphate, and magnesium remained constant and were unaffected by the rate of agitation, as also was the specific growth rate, but the latter decreased with increasing glucose concentration.A period of linear growth could follow the exponential period. The contribution of glucose was greater, and that of phosphate and magnesium less, than during exponential growth. The dry weight at which exponential growth changed to linear growth was greater the higher the rate of agitation, and this change may be a response to oxygen restriction.After nitrogen exhaustion, fat and carbohydrate accumulation in the cells largely accounted for the increase in dry weight. The specific rates of dry weight increase and glucose uptake remained constant over the lower range of initial nitrogen concentrations. Both rates decreased with increasing nitrogen over the higher range.Gibberellic acid production began at, or soon after, nitrogen exhaustion. The amount present increased linearly with time. The productivity decreased with increasing glucose concentration, and first increased and then decreased with increasing initial nitrogen. The maximum amount produced was proportional to the initial nitrogen provided. Some published results are discussed in the light of these relations.

ISSN:0008-4166    

DOI:10.1139/m64-054

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

The metabolism ofGibberclla Jujikuroiin stirred culture has been studied at varied temperatures over the range 8–40 °C. Two nitrogen-limited media were used, which differed only in the initial concentration of ammonium tartrate. Economic and rate constants have been derived at each stage of fermentation, and methods of relating these to temperature discussed. Each has been related to temperature both by a linear plot, and according to the Van"t Hoff – Arrhenius model.There was no significant difference between the results from the two media early in fermentation. During the storage and maintenance phases all specific rates were considerably lower on the more concentrated medium.The minimum temperature for growth was below 8 °C. Many parameters showed a discontinuity in the range 17–20 °C, and most optima were in the range 29–32 °C. At 38 °C growth ceased when the dry weight was about 2 mg/g of unfiltered broth, and no growth occurred at 40 °C.The contribution of nitrogen to dry weight was virtually independent of temperature. The glucose contribution tended to decrease slightly with increasing temperature over the whole range. The phosphate contribution was constant in the range 8–20 °C, and decreased greatly with increasing temperature from 20 to 36 °C. The magnesium contribution decreased markedly with increasing temperature over the whole range.Two general forms of relation between rate constants and temperature were found. One, a typical "skew" curve with "tail-off' at the lower temperatures, was obtained with the specific growth rate, the nitrogen and glucose quotients, the specific rate of glucose uptake in the maintenance phase, and the gibberellic acid productivity. The second relation showed a marked discontinuity in the range 17–20 °C, above which the increase with increasing temperature was less than at the lower temperatures. This form of curve was obtained with the phosphate, magnesium, and carbohydrate quotients, the linear growth rate, the rate of increase in mycelial dry weight, fat and carbohydrate in the storage phase, and the rate of glucose, phosphate, and magnesium uptake in the same period.

ISSN:0008-4166    

DOI:10.1139/m64-055

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Pseudomonas aeruginosastrain 64 has previously been demonstrated to produce an extracellular slime material containing deoxyribonucleic acid and mannan as major constituents. Results reported here indicate that the extracellular deoxyribonucleic acid arises spontaneously from an intracellular origin owing to cellular disintegration without experimental intervention. Cellular disintegration occurs between the first and fifth days of cultivation. It is suggested that cellular disintegration may be due to lysogenic and (or) pyocinogenic phenomena.Production of extracellular mannan, on the other hand, was shown to occur during the first 24 hours of cultivation. Mannose, which was demonstrated to be a carbohydrate of the cell membrane, was not present in cells in sufficient quantity to account for total extracellular mannan. Thus, mannan was indicated to be synthesized de novo and excreted into the medium, possibly as a capsular polysaccharide.Glucose and glucosamine were the only two carbohydrates detected in hydrolysates of cell walls ofP.aeruginosastrain 64, while mannose was the only carbohydrate detected in cell membranes.

ISSN:0008-4166    

DOI:10.1139/m64-056

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Cell wall replication inE.coliandS.faecaliswas studied by differential labelling of living cells with fluorescent and non-fluorescent antibody.InE.colithe initial step in cell division was the formation of a cross wall at the cell equator, followed by the appearance of new cell wall on either side of the cross wall. The process was repeated in sequence at subsequent sites in the polar, the subcentral, and the subpolar areas. Constriction occurred at random so that the divided parent cells were composed of several daughter cells.A polar type of unidirectional cell wall growth and elongation was also observed inE.coli. It was initiated by the synthesis of a ring of new cell wall material around the polar tip. A second ring was then formed at the subpolar area during the rapid enlargement of the first ring in a single direction.Evidence shows that cell wall synthesis is independent of cell division and that inE.coli, it is initiated at multiple but specific sites within the cell and not by diffuse intercalation of old and new walls.Contrary to the synthesis of cell wall at multiple sites inE.coli,S.faecalisreplicated new cell wall at only one site per coccus. The new wall segment was initiated and enlarged at the coccal equator, and was followed by the formation of a cross wall, centripetal growth and constriction to separate the daughter cells.

ISSN:0008-4166    

DOI:10.1139/m64-057

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

In the electron microscope, isolated cell envelopes of the extremely halophilic bacterium,Halobacterium cutirubrum, have the same hexagonal surface pattern and roughly the same shape as do intact cells. At different pH values and in different ionic environments the envelopes undergo changes in shape and surface structure similar to those of intact cells. These changes are probably not due to osmotic pressure. In media of low ionic strength envelopes disintegrate. This disintegration appears to involve at least two reactions, both temperature-dependent.Chemical analyses show that envelopes consist mainly of lipoprotein. Both lipid and protein components are negatively charged at neutral pH, and this may help to explain the dependence on high cationic concentrations for envelope stability. Most of the cell"s phosphatides are present in the envelope. The main phosphorus-containing components of cells are acid-soluble compounds and nucleic acids, whereas the main phosphorus-containing components of envelopes are phosphatides. Envelopes also contain small amounts of hexoses, hexosamine(s), and nucleic acids with a higher RNA/DNA ratio than found in intact cells, but neither muramic acid nor diaminopimelic acid was present. The lack of muramic acid inH.cutirubrumindicates that this halophile does not have a rigid mucopeptide wall of the type found in other bacteria. The lack of mucopeptide in envelopes is not due to autolytic digestion of mucopeptide during envelope isolation.

ISSN:0008-4166    

DOI:10.1139/m64-058

出版商:NRC Research Press    

年代:1964

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m64-059

出版商:NRC Research Press    

年代:1964

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m64-060

出版商:NRC Research Press    

年代:1964

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m64-061

出版商:NRC Research Press    

年代:1964

数据来源: NRC