摘要:

TheErwiniasp. studied possesses a discrete mucopeptide layer. This layer contains glutamic, diaminopimelic, and muramic acid, glucosamine, and alanine (1–1–1–1–2) as major components. Aspartic acid, glycine, and an unidentified ninhydrin-positive compound are also present but in lesser amounts. Content of glycine increases when cells are grown in a defined medium in the presence of glycine. Serine is present in the mucopeptide when cells are grown in the presence ofD-serine, an inhibitor of cell division. Serine can partially replace glycine. Incorporation of serine is not significantly decreased by agents capable of preventing division inhibition byD-serine (pantoyl lactone or ammonium chloride). A new method for isolation of pure mucopeptide is presented.

ISSN:0008-4166    

DOI:10.1139/m65-080

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The fungistat, sorbic acid, has been shown to inhibit the activity of catalase. This inhibition is related to sorbic acid concentration, pH of the system, and length of time that the catalase was exposed to the acid. Both mold and mammalian catalases are inhibited, and mammalian catalase is shown to reverse the inhibitory effect of sorbic acid on molds. The rates of oxygen uptake by germinated and ungerminated spores have been compared in the presence and absence of sorbic acid, and it has been shown that sorbic acid exerts its most profound effect on spore germination. The possible significance of the auto-oxidative breakdown of sorbic acid is discussed.

ISSN:0008-4166    

DOI:10.1139/m65-081

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The chromatographic analysis of the mycelial extract revealed the presence of the following amino acids: cystine, lysine, arginine, histidine, serine, glycine, aspartic, glutamic, threonine, α-alanine, proline, α-aminobutyric, tyrosine, valine, and leucine. Of these, glutamic, aspartic, alanine, valine, leucine, glycine, and serine were the major components. No qualitative change was noticed in the types of the amino acids of 2-, 4-, 6-, and 8-day-old cultures. With the increasing age of the culture, glutamic and alanine decreased while serine and glycine increased. Aspartic and threonine did not show noticeable variations in quantity. Pyruvic and α-ketoglutaric acids were the only detectable keto acids either in the cell pool or in the culture medium. The mycelial cell-free extracts exhibited glutamic–oxalacetic transaminase and glutamic–pyruvic transaminase activities.

ISSN:0008-4166    

DOI:10.1139/m65-082

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The major amount of riboflavin is formed when the mycelia reach a mature stage and the major carbon source is almost exhausted. While the riboflavin is being synthesized in larger quantities, the mycelial dry weight, the total nitrogen, and total lipid content decrease. The mobilized cell reserves may be those components which call upon the biosynthesis of the major amount of the vitamin. At the stage of growth where glucose is almost completely utilized an increase in the excretion of pyruvic and lactic acids from the mycelia into the culture medium occurs. This may partly explain the increase in the acidity of the culture medium at that stage.

ISSN:0008-4166    

DOI:10.1139/m65-083

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

A replica plating method was developed to study ecology of microorganisms in soil. Precise placement of inocula and amendments at desired loci in sterile soil contained in petri plates were accomplished with a template. Subsequent growth and distribution of individual species, even when part of a mixed population, was measured by periodic transfer with an easily constructed replicator to agar plates of differing nutritional composition or containing selective inhibitors. The method is rapid and reproducible, and permits the study of many variables and interactions in a single soil plate; it can also be used with non-sterile soil and other suitable microbial habitats.

ISSN:0008-4166    

DOI:10.1139/m65-084

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The in vitro antimicrobial activity of selected pharmacological agents was studied against five strains of staphylococci (phage types 7 US, 54, 71, 80, 81). At the concentrations used (maximal 0.125 μg/ml) chlorothiazide, acetazolamide, FeCl3, SnCl2, stilbamine urea, quinacrine, antimony Na thioglycollate, antimony thioglycollamide, and sulfisoxazole were found to have no antimicrobial effect against these strains of staphylococci, whereas HgCl2, AgNO3, meralluride sodium, stilbamidine, pentamidine, and propamidine did show activity. When effective agents were combined with potassium phenoxymethyl penicillin, the bacteriostatic action of the antibiotic was inhibited in some cases and markedly potentiated in others. Consideration should be given to the possible incorporation of effective agents into the structure of synthetic antibiotics as a means of combating resistant staphylococci.

ISSN:0008-4166    

DOI:10.1139/m65-085

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Two-dimensional analogues of spherulites are formed in the pellicle of bacterial cellulose produced by static cultures ofAcetobacter xylinum. These spherulites are much larger (sometimes more than 1 cm diameter) than those usually observed in other natural or synthetic polymers. They are due to the radial orientation of bacterial cellulose microfibrils in limited regions of the plane of the pellicle. These spherulites interact to form characteristic, dendritic structures of great complexity which resemble leaves of higher plants.

ISSN:0008-4166    

DOI:10.1139/m65-086

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Electron micrographs of sections ofThioploca ingricaand ofBeggiatoashowed that the wall of both consisted of multiple and similar layers, of which only the innermost took part in septum formation.Thioploca, however, contained an additional wall component. Invaginations of the cytoplasmic membrane produced extensive intracytoplasmic membranes in both organisms. Sulfur appeared to be deposited within this membrane system, which was accentuated inThioplocaby an enclosure of dense, vesicular material. The deposition of sulfur external (in effect) to the cytoplasmic membrane was also found when hydrogen sulfide and air were bubbled through cultures of a number of Gram-negative bacteria not considered to be sulfur bacteria. The cytoplasm ofBeggiatoawas richer in ribosomes than the extraordinarily dense cytoplasm ofThioploca, and the lipid deposits of both left behind spaces that were not membrane-bounded. Metachromatic granules were observed only inBeggiatoa. A heterotrophic strain ofBeggiatoacontained a diffuse nucleoplasm, but nucleoplasms could not be recognized either in the wild type or inThioploca.ThioplocaandBeggiatoaare sufficiently different in their infrastructure to be considered distinct organisms. The former consistently produce sheaths. Similarities in structure and in the arrangement of components are enough to support a family relationship.

ISSN:0008-4166    

DOI:10.1139/m65-087

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

An alcohol extract of amino acids was made from fresh leaf litter of five common trees. The amino acids isoleucine, tyrosine, glutamic acid, aspartic acid, and serine were detected chromatographically. Several aquatic Hyphomycetes were then grown in the presence of aspartic acid, lysine, glutamic acid, tyrosine, arginine, and casein. Apart fromVolucrispora aurantiaca, the carbon of all amino acids except lysine was found to be available for metabolism. The nitrogen of all amino acids was also available, except thatV.aurantiacacould utilize only arginine, asparagine, and to a lesser degree, lysine. It is concluded that a wide range of amino acids and probably of plant proteins in general can supply available nitrogen to many aquatic Hyphomycetes.

ISSN:0008-4166    

DOI:10.1139/m65-088

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The sulfur metabolism ofE.coliB in glucose–salts medium was studied. When sulfate was omitted from the medium, a population of washed, log phase cells increased in both turbidity and plate count in a manner suggesting two, apparently different, endogenous pools of sulfur-containing materials. In addition, it was found that the sulfur-deficient medium contained a small but significant level of available sulfur. This contaminating exogenous sulfur could be removed from the medium by incubation of the cell suspensions for 9–10 hours. Afterward, the starved cells were removed and replaced by cells in any desired state. Starved cells grew briefly, utilizing the sulfur impurities in the standard deficient medium, but began to die soon after reaching the maximum population. When the additions were small, added sulfate induced increases in turbidity by suspensions of starved cells after lag periods. Further, a sensitive turbidimetric analysis of the response of starved cells by an extrapolation method as a function of the amount of added sulfate revealed that no level of exogenous sulfate could be detected which did not stimulate growth. Therefore, no threshold or maintenance level, at least above 10−10 mole/ml for 2.5 × 108 cells/ml, exists for sulfate. Implications of these findings are discussed.

ISSN:0008-4166    

DOI:10.1139/m65-089

出版商:NRC Research Press    

年代:1965

数据来源: NRC