摘要:

Somatic antigen groups and minimal somatic antigen constitution of 28 strains ofRhizobium japonicumwere determined on the basis of their somatic cross-reactions and agglutinin absorptions. A total of 17 serological groups and 24 antigens was proposed to account for the reactions obtained. Some groups consisted of a complex of three or four strains while others comprised only one strain. Still others were composed of strains which were common to two serological groups. The antigenic complexity of rhizobial cells and the possibility of using "key-antisera" and polyvalent mixtures of "key-antisera" are discussed in relation to the classification of large numbers of field or greenhouse nodule isolates inRhizobiumcompetition studies.

ISSN:0008-4166    

DOI:10.1139/m65-001

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The relative growth-stimulating properties of various animal fractions were measured in vitro using a rainbow trout gonadal cell line. No significant differences were noted at the end of a 12 day growth period when 10% of either human serum, bovine serum, or ascitic fluid was added to the basal medium. Ascitic fluid stimulated early growth of the cells but did not result in greater final numbers and apparently caused early degeneration of the cell. Fetal calf serum, bovine embryo extract, and human or bovine serum were required for maximum proliferation of rainbow trout gonadal cells in these experiments.

ISSN:0008-4166    

DOI:10.1139/m65-002

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Glucose and dextrin were compared for their ability to support toxinogenesis in cultures of strain D7 ofClostridium perfringenstype D with pH controlled at 7.0 or uncontrolled. At pH 7.0 both carbohydrates supported toxinogenesis equally: the yields of alpha, epsilon, kappa, and theta toxins were 20 MLD, 70,000 to 80,000 MLD, 400 to 500 arbitrary units (K.U.) and 30 hemolytic units (H.U.) respectively. With uncontrolled pH, dextrin was superior to glucose: with dextrin in the medium the yields were 10 MLD, 16,000 MLD, 200 K.U., and 3 H.U. while with glucose they were 1 MLD, 1500 MLD, 100 K.U., and 3 H.U. of alpha, epsilon, kappa, and theta toxins respectively.The time of epsilon toxin synthesis during fermentation at pH 7.0 was affected by the carbohydrate used. With dextrin, toxinogenesis paralleled growth, but with glucose most of the toxin was produced at the end of the growth period.Synthesis of epsilon, kappa, and theta toxins by three other strains ofC.perfringenstype D in cultures without pH control was also reduced consistently when dextrin was replaced with glucose. At pH 7.0 toxinogenesis was, with few exceptions, the same in cultures with dextrin and glucose.

ISSN:0008-4166    

DOI:10.1139/m65-003

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The spent medium from cultures of the chemoautotrophFerrobacillus ferrooxidansgrown in a ferrous iron – salts medium was examined for organic compounds. Pyruvic acid was identified by chromatography after precipitation of the iron salts, and was determined at various times during the culture growth cycle. Analyses of the spent medium from cultures grown in the presence of C14O2indicated that a large portion of the CO2fixed by the organism was released into the medium. A significant portion of the radioactivity in the medium could be extracted as the 2,4-dinitrophenylhydrazone derivative. Very little radioactivity was extracted by ether, indicating that phospholipids are probably not released into the medium by this organism.

ISSN:0008-4166    

DOI:10.1139/m65-004

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The occurrence of free-living nitrogen fixers, the potential for nitrogen fixation, and the correlation between the nitrogen-fixing capacities of the soils and bacterial counts were studied using representative Quebec soils.Clostridiumoccurred more frequently than didAzotobacter. Studies with N15showed that nitrogen fixation was more frequent under anaerobic than under aerobic conditions in all the soil types studied in their unamended state. The addition of glucose stimulated nitrogen fixation. During anaerobic incubation, nitrogen fixation was found to be correlated significantly with the increase in numbers of both total aerobes and Clostridia. The results suggested that facultatively anaerobic nitrogen fixers, and aerobic nitrogen fixers other thanAzotobacter, were present.

ISSN:0008-4166    

DOI:10.1139/m65-005

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Phase-contrast studies on amnion cells in suspension following trypsinization of membranes showed the cells to be usually markedly vacuolated and highly refractile and the nucleus to be obscured; a few cells were non-vacuolated, dark, and smaller. Studies were initiated to determine the origin of the small dark cells and their growth in cell culture, utilizing a series of staining technics to elaborate the differences seen by phase-contrast microscopy.Biopsies of amniotic membranes from Caesarian sections more frequently showed less vacuolation of epithelium as compared to amnions from normal deliveries, which were usually markedly vacuolated; trypsinization of membranes made up of non-vacuolated epithelium yielded suspensions made up entirely of smaller, dark cells. Studies on the process of cell separation showed this change of the non-vacuolated cells to smaller dark cells to be an effect of trypsin. The small dark cells were superior to the vacuolated cells for culture purposes.

ISSN:0008-4166    

DOI:10.1139/m65-006

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

A strain ofClostridium perfringenstype D was grown in a complex medium with or without pH control. Rate and extent of growth was the same without pH control and at controlled pH levels between 6.0 and 7.4, but was reduced at pH 7.6. With controlled pH at optimum levels the yields of alpha, epsilon, kappa, and theta toxins were 2, 6, 2, and 8 times higher than without pH control. These yields were 25 MLD, 70 × 103 MLD, 400 kappa units, and 60 hemolytic units per milliliter respectively. Optimum pH was 7.0 to 7.2 for alpha, 6.7 to 7.4 for epsilon and kappa, and 7.0 to 7.4 for theta toxin. Lambda and mu toxins were not produced, and only traces of nu antigen were formed.Fourteen additional strains ofC.perfringenstype D were grown with pH controlled at 7.0 or without pH control and assayed for production of epsilon, kappa, and theta toxins. Epsilon was formed by 14, kappa by 10, and theta by 13 strains. With pH controlled at 7.0, 14 strains produced more epsilon toxin, 4 strains more kappa toxin, and 10 strains more theta toxin than without pH control. It is concluded that increased toxinogenesis at controlled pH is a general phenomenon in cultures ofC.perfringenstype D.

ISSN:0008-4166    

DOI:10.1139/m65-007

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The production of pigments by fungi of the genusElsinoë(Ascomycetes) and the corresponding imperfect stage,Sphaceloma, has been studied. Three closely related pigments, the elsinochromes A, B, and C, are formed by most of them in varying proportions. These pigments have been isolated in pure form and have been shown to be derivatives of 4,9-dihydroxyperylene-3,10-quinone. The same pigments are also formed by an imperfect fungus designated as "Phyllosticta caryaePk." However, this fungus had been identified earlier as a conidial stage ofE.randiiJenkins and Bitancourt, an interpretation which is supported by the present findings concerning pigment production.

ISSN:0008-4166    

DOI:10.1139/m65-008

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Culture filtrates from surface and deep cultures ofAspergillus oryzaewere tested for the presence of stimulatory and inhibitory substances, by examining the effect of the nitrates, when added with the inoculum, on growth rate and maximum yield of stationary cultures of the same organism. Filtrates were prepared from various stages of both large- and small-inoculum cultures by each method of growth.Both stimulatory and inhibitory substances were found. Inhibitory substances predominated in the filtrates from early stages of a small-inoculum culture, more especially when these were derived from a deep culture, which showed a pronounced effect of inoculum size. At other stages of growth of small-inoculum cultures and all stages of growth of large-inoculum cultures tested, stimulatory substances were found.It is emphasized that the stage of production of such substances is of crucial importance. Inhibitory substances acting at an early stage of growth of small-inoculum cultures have an adverse effect on growth of late stages. If, however, stimulatory substances are present in sufficiently high concentration at a sufficiently early age, as in large-inoculum cultures, they exert a favorable influence on later stages of growth. These phenomena explain the effects of inoculum size.

ISSN:0008-4166    

DOI:10.1139/m65-009

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

not available

ISSN:0008-4166    

DOI:10.1139/m65-010

出版商:NRC Research Press    

年代:1965

数据来源: NRC