ISSN:0008-4166    

DOI:10.1139/m77-139

出版商:NRC Research Press    

年代:1977

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m77-140

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

An amylopectinlike polysaccharide (granulose) was the only glucan produced in significant quantities by six wild-type strains ofClostridium pasteurianumgrown in glucose minimal medium. The intracellular polysaccharide granules laid down before sporulation contained only this amylopectin. No intracellular dextran was discovered in these wild-type strains, nor in a granulose-negative mutant strain ofC.pasteurianumpossessing an ADP glucose pyrophosphorylase (EC 2.7.7.27) but lacking a granulose synthase (i.e. ADPglucose-α-1,4-glucan glucosyl transferase, EC 2.4.1.21). Furthermore, methylation analysis demonstrated that (1 → 6) linked α-D-glucose units accounted for less than 2% of the entire glucose content of these organisms.

ISSN:0008-4166    

DOI:10.1139/m77-141

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Polynucleotide sequence relationships among 19 strains of marine vibrios, 15 of which were pathogenic to fish, were assessed by analysis of DNA–DNA homo- and hetero-duplexes with the endonuclease S1. DNA base compositions (mole% guanine–cytosine (GC) of selected vibrio strains were determined by thermal denaturation. Pathogenic strains from the Pacific Northwest had identical mole % GC but could be divided into two discrete, yet related, DNA-homology groups. One highly related group was typical ofVibrio anguillarumand showed greater than 70% within-group polynucleotide sequence homology. Second group (designated V1669) showed greater than 83% within-group homology but only about 60% relatedness toV.anguillarum. Neither group showed a significant degree of relatedness toV.parahaemolyticus(biotypes parahaemolyticus or alginolyticus) or to representative strains of any of the other previously described homology groups which we tested.

ISSN:0008-4166    

DOI:10.1139/m77-142

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The mycelium of the phytopathogenic fungusSclerotium rolfsiitype R (ATCC 26326) grown on a solid medium supplemented with 10 mML-threonine exhibits a synchronous formation of sclerotia in circles whereas both leading and lateral hyphae enter into a rhythmic growth rate. A rhythmic activity of malate synthetase (malate synthase, EC 4.1.3.2) which accompanied the hyphal rhythm and preceded the formation of sclerotial circles was demonstrated. Both translocation ofL-[14C]threonine and incorporation ofL-[14C]leucine were significantly related to the circadian formation of sclerotia.

ISSN:0008-4166    

DOI:10.1139/m77-143

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

A simple crude system for the incorporation of tritiated diaminopimelic acid (3H-DAP) into a polymer with characteristics of spore cortical peptidoglycan has been obtained from cells ofBacillus cereusvar.alesti, harvested and disrupted in a French pressure cell, at the time of late cortex formation (sporulation stage 5). The small fraction of whole cells remaining in the homogenate were not responsible for the observed incorporation. The radioactive product was sensitive to digestion by lysozyme as is cortex formed in vivo. Preparations obtained at the same time of sporulation, from a mutant unable to form cortex, were unable to incorporate3H-DAP into peptidoglycan. However, homogenates prepared at the time of germ cell wall formation (early stage 4) from both parent and cortexless mutant produced radioactive peptidoglycan which was more resistant to lysozyme as is germ cell wall produced in vivo in this species. Bacitracin and vancomycin inhibited incorporation of3H-DAP into peptidoglycan by over 90% in both cell wall and cortical preparations. Methicillin caused a striking inhibition of3H-DAP incorporation into peptidoglycan by the cortical system in contrast to its almost total lack of inhibition of the cell wall or germ cell wall systems. Over 90% of the DAP incorporated was the expectedmeso-isomer.3H-DAP-labelled lipid intermediate was produced by the system. Cross-linking of newly synthesized material was observed. This in vitro system appears satisfactory for the further study of some aspects of the biosynthesis of cortical peptidoglycan.

ISSN:0008-4166    

DOI:10.1139/m77-144

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

An immunoglobulin G (IgG)–containing fraction was isolated from milk, obtained from a goat before and after instillation of the mammary gland withNeisseria gonorrhoeaecolony type 1 (T1). The presence of IgG and the absence of immunoglobulins-A and -M in this fraction was confirmed by immunodiffusion in gel and immunoelectrophoresis. Postinstillation IgG inhibited the attachment of the homologous strain ofN.gonorrhoeae(T1) to tissue cells. The percentage of Rhesus monkey kidney cells with gonococci attached was 38.9% ± 6.4. Inhibition was significant (P < 0.01) when compared to the inhibitory effect of preinstillation IgG (73.5% ± 3.1) or buffer control (76.8% ± 2.8). Absorption of postinstillation IgG with rabbit anti-goat IgG or whole cell gonococci removed the inhibitory effect. Postinstillation IgG gave little or no inhibition of attachment (maximum 13%) of seven heterologous (T1) strains ofN.gonorrhoeaeto tissue cells. These results may provide a reason for recurrent gonococcal infection in humans despite the presence of circulatingantibody (IgG) toN.gonorrhoeae. Such an antibody, if present in secretions bathing the mucosa, may fail to prevent infection and colonization of the urogenital tract by a different immunotype ofN.gonorrhoeae.

ISSN:0008-4166    

DOI:10.1139/m77-145

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

A useful plate culture method for isolating oligotrophic bacteria found in the low-nutrient environment of the open sea has been developed. The method uses a glass-fiber filter substitute for agar. Nutritional requirements of oligotrophic bacteria consisted of a dilute nutrient solution containing 16.8 mg C/ℓ total organic carbon aseptically added to the sterilized filter. Distribution of bacteria in oceanic and neritic seawater was determined using the membrane filter method. In the case of seawater containing less than 0.5 mg/ℓ dissolved carbohydrates, plate counts of oligotrophic bacteria were found to be several- to 100-fold greater than the heterotrophic bacterial counts enumerated by standard methods routinely used for enumeration. However, in seawater containing approximately over 0.5 mg/ℓ dissolved carbohydrates, heterotrophic bacterial counts were 10-fold greater than oligotrophic bacterial c

ISSN:0008-4166    

DOI:10.1139/m77-146

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

An earlier proposal (Can. J. Microbiol. 7: 851; 1961) that rj1rj1(non-nodulating) soybeans (Glycine max(L.) Merr.) excrete a substance that inhibits nodulation of Rj1Rj1(nodulating) plants was tested. Using near isogenic lines (isolines) of 'Clark' and 'Harosoy' soybeans, we consistently found nonsignificant reductions in nodule number and acetylene reduction per Rj1Rj1plant grown in association with their rj1rj1counterparts; these results suggest that a nodulation inhibitor is not associated with the rj1gene. Reducing the number of plants grown in each pot produced significant (P = 0.05) reductions in nodule number per Rj1Rj1plant, and resembled the observations of the earlier report. On this basis, we suggest that the reported inhibition of nodulation was due to a failure to detoxify or remove an inhibitor (possibly nitrate) already present in the nutrient solution. Both Clark isolines removed nitrate from their nutrient solutions at similar rates. Harosoy rj1rj1plants removed nitrate at a significantly (P = 0.05) slower rate than Harosoy Rj1Rj1plants, but the differences were not correlated (P = 0.05) with the small observed decreases in nodulation. These differences in nitrate uptake were highly correlated (P = 0.01) with reduced dry weight per Harosoy rj1rj1plant.

ISSN:0008-4166    

DOI:10.1139/m77-147

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The effects of four cations, Ca2+, Mg2+, K+, and Fe3+, upon the production of zoosporangia by isolates of four species ofPhytophthorain axenic culture have been investigated. A response surface design was used to examine main effects and possible interactions.Responses to Ca2+and Fe3+were strongly quadratic with the higher concentrations inhibiting sporangial production inP.cinnamomiandP.drechsleriisolates. Responses to Mg2+and K+were weaker and, in the case of magnesium, were linear rather than quadratic. There was no significant interaction between cations except in the case ofP.cambivorawhere the interaction between Mg2+and K+was significant at the 5% level. For each cation, the optimum concentration for zoosporangial production was calculated.The processes of zoospore release and infection of plant material byP.drechslerishowed a strong linear and weak quadratic response toCa2+, higher concentrations of Ca2+favouring these processes. A strong quadratic response was obtained toMg2+, K+, and Fe3+. Interaction between Ca2+and Mg2+was evident for all three host materials used; Mg2+and K+showed an interaction whenPinus radiatawas used as the host material. The implications and limitations of these results are discussed.

ISSN:0008-4166    

DOI:10.1139/m77-148

出版商:NRC Research Press    

年代:1977

数据来源: NRC