摘要:

A study was made of the predominant yeasts that occur on apples grown in Quebec, and in cider. The yeasts isolated from apples were members of the familyCryptococcaceaeand of the generaCandida,Cryptococcus,Rhodotorula, andTorulopsis. Species ofCandidawere by far the most predominant. The yeasts isolated from cider were representatives of the generaDebaryomyces,Pichia, andSaccharomyces. All the yeasts studied were classified into species of the respective genera.

ISSN:0008-4166    

DOI:10.1139/m55-019

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

A standard vegetative inoculum ofAspergillus nigerhas been developed for the submerged citric acid fermentation of sugar beet molasses. Increasing the ferrocyanide content and the pH of the seed mash, within limits, decreased the rate of development of the mold pellets whereas increasing the spore inoculum increased the rate of development. Using this "standard" inoculum, an average yield of 8.9% anhydrous citric acid (68.5% conversion of available sugar) was obtained in 116 hr. The standard deviation between runs was 4.5% of the mean citric acid yield. An abrupt breakdown of the fermentation process decreased the yield by 50% and increased the standard deviation to 28.5% of the mean yield. The breakdown was overcome by changing the sporulation medium from a chemically-defined synthetic type to a nutritionally-richer type. Results indicate that serial transfer on a synthetic medium weakened the culture and made the fermentation unstable.

ISSN:0008-4166    

DOI:10.1139/m55-020

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Optimal conditions have been established for the propagation of influenza virus (PR8strain) in various chick embryonic tissues cultivated in synthetic medium 199. The propagation of several other influenza strains, both standard laboratory and freshly-isolated, and of mumps virus, has also been studied. Comparative investigations with virus-infected tissues cultivated in medium 199 and in simple inorganic salt solutions have shown that the extent of virus propagation is more dependent on the intracellular material present in the tissues than on the composition of the extracellular culture medium. It has also been shown that virus propagation occurs equally well in healthy, surviving cells, in actively-growing cells, and in cells depleted of nutrients and undergoing degeneration.

ISSN:0008-4166    

DOI:10.1139/m55-021

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Stages in the development of viruses of two Hymenopterous insects,Diprion hercyniae(Htg.) andNeodiprion americanus banksianaeRoh., are shown in electron micrographs of thin sections. Following swelling of the nuclei and nucleoli and coagulation of the chromatin, rod-shaped virus particles appear chiefly on the exposed surfaces of the chromatin. The chromatin ofD.hercyniaeoften coagulates into separate lumps that suggest small polyhedra. These first produce rod-shaped particles on their exposed surfaces and later transform into recognizable polyhedra. The chromatin ofN.a.banksianaeis more uniformly dispersed, and polyhedra arise as thickenings within the chromatin. In the latter insect, virus particles are frequently observed within the developing polyhedra, suggesting that polyhedra are formed by the accumulation of protein around groups of virus particles. Both polyhedra and free virus particles are larger and denser in the nuclear sap than in the chromatin. Their formation continues in remnants of chromatin in nuclei otherwise filled with large polyhedra. An incidental observation is that the nuclear membranes of some nuclei are pitted with small holes.

ISSN:0008-4166    

DOI:10.1139/m55-022

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

It is shown that the growth ofMycobacterium tuberculosisor a rapidly growing strain ofMycobacteriumin Dubos' medium is not influenced by the addition of low concentrations of cysteine or ferric salts, when added separately. But when cysteine and a ferric salt, both in low concentrations, are autoclaved together in the medium, the medium will not support growth ofMycobacterium. This inhibitory action only occurs when the cysteine–iron containing medium is at pH 6.8 or a more acid reaction. It is concluded that cysteine and ferric iron react in acid solution to produce a toxic end product.

ISSN:0008-4166    

DOI:10.1139/m55-023

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

It has been shown that when low concentrations of cysteine and ferric ammonium citrate or other ferric salts in distilled water, adjusted to faintly acid reaction, are repeatedly autoclaved, an insoluble granular precipitate forms. Chemical analysis of the precipitate indicates that it is sulphur. X-ray photographs of the precipitate and orthorhombic colloidal sulphur, while showing broadly similar patterns, possess significant differences which indicate that the precipitate has a lower symmetry or larger unit cell in its arrangement of sulphur atoms than has orthorhombic sulphur. This precipitate added to Dubos' medium in concentrations of 0.5 to 4 μgm. per ml. inhibits growth ofM.tuberculosis. In a concentration of 10 μgm. per ml. growth of all of four other Gram positive species of bacteria and three of five Gram negative species was inhibited. Colloidal sulphur had a similar growth inhibiting property but larger concentrations were required than of the precipitate prepared from cysteine and iron.

ISSN:0008-4166    

DOI:10.1139/m55-024

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Moderate growth ofHelminthosporium sativumoccurred in a simple medium with nitrate, ammonium, or amino nitrogen and was greatly improved by yeast extract. In the presence of a suitable nitrogen source ashed yeast extract also was stimulatory. Growth was markedly increased by a mixture of trace elements but was not influenced by a combination of eight known vitamins. The stimulatory effect of trace elements was noted also with different strains ofH.sativumand several related species (H.biforme,H.halodes,H.setariae,H.siccans,H.victoriae). In the presence of trace elements, several amino acids, especiallyl-proline anddl-serine, appeared more favorable for growth ofHelminthosporiumthan others tested. Nitrogen source as well as trace elements exerted a distinct effect on type of growth and pigmentation. Zinc appeared to be essential for growth ofH.sativum; manganese, iron, and boron also may be of importance.

ISSN:0008-4166    

DOI:10.1139/m55-025

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

The utilization of heptoses and related compounds by bacteria and yeasts was investigated. Most cultures metabolized sedoheptulose, which was the only sugar dissimilated under both aerobic and anaerobic conditions. No other heptuloses were utilized by these organisms. Some cultures were able to oxidize various heptoses to the corresponding heptonic acids and certainAcetobacterstrains produced other compounds. Heptitols were attacked by only theAcetobacterspecies. Heptonic acids were utilized slightly by a few organisms.

ISSN:0008-4166    

DOI:10.1139/m55-026

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Conditions have been established for the oxidation of naphthalene by a pseudomonad based on the yields of ether extractable substances. Vigorous aeration yielded approximately three times the product obtained from unaerated controls. Oxidations with media adjusted initially to pH 8 gave higher yields than those adjusted to lower pH levels. Calcium and copper appeared to be necessary for maximum yields. Under the conditions described, the non-naphthalenic ether extractable substances amounted to as much as 29% of the original 1% naphthalene. Purification and analysis of the crude extract showed that it consisted largely of salicylic acid. Some properties of the remaining material are described.

ISSN:0008-4166    

DOI:10.1139/m55-027

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

A colloidal sulphur preparation, formed by autoclaving a dilute solution of cysteine and ferric ammonium citrate, was shown to have no toxicity for mice after eleven 1-mgm. intravenous doses on alternate days. Single doses up to 2 mgm. subcutaneously were not toxic but larger doses by this route produced necrosis. A single 1-mgm. dose of the preparation given to mice intravenously afforded no protection against a lethal dose ofDiplococcus pneumoniaeType III when given simultaneously. However, groups of mice given a 1-mgm. intravenous dose of the complex and challenged with a lethal dose of pneumococcus at intervals up to 168 hr. after the therapy show no protection for the first 24 hr. following the therapy, increasing protection from 24 to 78 hr., complete protection at 78 hr., and decreasing protection from 78 to 168 hr.

ISSN:0008-4166    

DOI:10.1139/m55-028

出版商:NRC Research Press    

年代:1954

数据来源: NRC