摘要:

Several marine waters and surface sediments of coastal British Columbia were analyzed and compared for bacterial colony forming units (CFU) and numbers of active bacteria (NAB) as indicated by microautoradiography, glucose and alanine heterotrophic activities, and dissolved (DOC) and particulate organic carbon (POC). Bacterial numbers (CFU, NAB) were usually much greater (by several orders of magnitude) in surface sediments than in overlying waters. DOC and POC were also generally greater in surface sediments than in overlying waters, often by as much as one order of magnitude. Both glucose and alanine heterotrophic potentials were greater in surface sediments; however, on a per active cell (NAB) basis, no significant differences were noted between the glucose-specific activities of the bacteria of the surface sediments and overlying waters. The data suggest that these surface sediments carry greater standing crops of bacteria than overlying waters without significant decreases in glucose-specific activities.

ISSN:0008-4166    

DOI:10.1139/m81-041

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Intracellular calcium phosphate mineral formation inBacterionema matruchotiihas been examined relative to two established points: the product of calcium and phosphorus levels at which spontaneous precipitation occurs (Ca × P), 50 (mg %)2, and the product at which calcium hydroxyapatite itself induces crystal growth, 35 (mg %)2. The extent of intracellular mineralization in the defined calcifying medium was determined analytically after washing the cells. Electron micrographs ofB.matruchotiicells revealed needlelike crystals of mineral, typical of calcium hydroxyapatite.Bacterionema matruchotiiwas found to be an efficient nucleator and can bring about the formation of solid phase at a Ca × P product as low as 35 (mg %)2.

ISSN:0008-4166    

DOI:10.1139/m81-042

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

A total of 342 staphylococci representing 13 different recognized species were screened for plasmid composition using agarose gel electrophoresis techniques. Plasmids of molecular weight (MW) 30 × 106or larger in size were uncommon in staphylococci. Moderately large plasmids of MW 15 × 106to 29 × 106were not or only occasionally found in the speciesStaphylococcus sciuri,S.intermedius,S.hyicus, orS.simulans, but were common inS.aureus(55%) and members of theS.epidermidis(79%) andS.saprophyticus(86%) species groups. Small plasmids were common in most of the species. They produced more complex profiles in simian subspecies or biotypes than in human subspecies or biotypes, e.g., in the speciesS.warneri,S.haemolyticus,S.cohnii,S.xylosus, andS.aureus. Although some of the species appeared to have rather unique plasmid patterns, we would currently hesitate to use this feature as a taxonomic character, considering the occurrence of exceptional strains and possible plasmid transfer between species.

ISSN:0008-4166    

DOI:10.1139/m81-043

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Sludge type was found to affect the degree of association between seeded poliovirus type 1 (LSc) and sludge solids. The mean percent of solids-associated viruses for activated sludge mixed liquors, anaerobically digested sludges, and aerobically digested sludges was 57.2, 70.4, and 94.7, respectively. The degree of association between poliovirus and sludge solids was significantly greater for aerobically digested sludges than for the other two sludge types. Sludge solids associated viruses were eluted using 0.05 Mglycine buffer, pH 10.5–11.0, and subsequently concentrated by organic flocculation. The effectiveness of the glycine method in the recovery of solids-associated viruses was also found to be affected by sludge type. Significantly lower mean poliovirus recovery was found for aerobically digested sludges (14.5%) than for mixed liquors or anaerobically digested sludges (72.3 and 60.2%, respectively). The eluent used in the method was not as effective in dissociating the virus from aerobic sludge solids as it was for the other two sludge types. All other virus adsorption–elution steps of the method (i.e., virus concentration steps) were equally effective in poliovirus recovery for all three sludge types. It is suggested that future methods developed for the recovery of viruses from sludges be evaluated for the various sludge types likely to be tested.

ISSN:0008-4166    

DOI:10.1139/m81-044

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Polyacrylamide gel electrophoresis of the cellulolytic system from culture supernates ofAcetivibrio cellulolyticusshowed the presence of four major enzymes: a β-glucosidase, an exoglucanase, and two endoglucanases. The relative proportions of these enzymes in the culture supernate were affected by the nature of the cellulosic substrate and by the length of the incubation period. The molecular weights of the cellulolytic enzymes were β-glucosidase, 81 000; exoglucanase, 38 000; endoglucanase C2, 33 000; and endoglucanase C3, 10 400, as estimated by their electrophoretic mobilities relative to proteins of known molecular weight. Treatment of the high molecular weight endoglucanase with SDS–mercaptoethanol led to reversible dissociation of the enzyme into polypeptide subunits similar to the low molecular weight endoglucanase. Endoglucanase activity could be assayed for directly using a novel method of incorporating carboxymethyl cellulose in the polyacrylamide gels. The molecular weights and functions of these enzymes are compared with those detected in culture filtrates of various fungi.

ISSN:0008-4166    

DOI:10.1139/m81-045

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

FromAspergillus fumigatusI-21 (ATCC 32722), which grows at temperatures from 12 to 50 °C, three multistep, independently derived, cold-sensitive mutants unable to grow at 37 °C or below (Cs-37) were obtained by sequential exposure to ethylmethane sulfonate (strain AT2) orN-methyl-N′-nitro-N-nitrosoguanidine (AT1 and AT3). These mutants and ON5, a five-step Cs-37 mutant, were marked by mutations affecting spore color and nutritional requirements and crossed in four combinations by classical parasexual means.The heterokaryons demonstrated partial complementation with respect to auxotrophic requirements (suboptimal growth on minimal medium) and cold sensitivity (growth at 37 °C but not at 25 °C). Most presumed diploids, formed by exposure of the heterokaryons tod-camphor vapors, showed complete complementation but were unstable, as demonstrated by variations in spore sizes and markedly different ratios of segregant classes derived from different clones.Analysis of the segregants of the diploids or aneuploids, induced by Benomyl, indicated that multiple genes were responsible for cold sensitivity in each Cs-37 mutant, since segregants with various levels of cold sensitivity were obtained. The higher than predicted frequency of reversion to temperatures two or more steps back in the sequence of cold sensitivity mutations suggested that these genes or their products interacted. No Cs-37 segregant yielding a consistently lower frequency of revertants than the original mutants was obtained.

ISSN:0008-4166    

DOI:10.1139/m81-046

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The mechanism of cold sensitivity ofAspergillus fumigatusON5, a 37 °C-sensitive mutant derived fromA.fumigatusI-21 (ATCC 32722) by five sequential mutations, was investigated. The rate ofin vivoprotein synthesis by ON5 was not affected for 2 h following a shift from 45 to 34 °C, but the rate ofin vivoRNA synthesis dropped almost immediately. The RNA polymerases of ON5 possessed wild-type activityin vitroat a nonpermissive temperature (34 °C) indicating that the reduction in the rate ofin vivoRNA synthesis did not result from cold sensitivity in transcription, but was possibly a result of rapid feedback inhibition of transcription. Mutant ON5 was not able to produce ribosomes at a nonpermissive temperature as evidenced by the fact that no3H-labelled amino acids were incorporated into the monosome, large ribosomal subunit, or small ribosomal subunit at 34 °C. Ribosomal subunit assembly or ribosomal RNA processing appears, therefore, to be the cold-sensitive cellular function in ON5.

ISSN:0008-4166    

DOI:10.1139/m81-047

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Facultatively anaerobic bacteria, capable of fixing N2anaerobically or at low O2concentrations, were isolated from the gastrointestinal tracts of temperate (Strongylocentrotus droebachiensis) and tropical (Tripneustes ventricosus) sea urchins. Morphological and biochemical characteristics, as well as the guanine plus cytosine content of their DNA (45.9 and 48.4 mol%), place these isolates in the genusVibrioPacini 1865 in the family Vibrionaceae. Members of this family have not previously been shown to fix N2. These isolates are not identical to any described species in theVibriogenus and can be distinguished by a combination of biochemical and physiological traits.

ISSN:0008-4166    

DOI:10.1139/m81-048

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Two Chesapeake Bay isolates of unicellular cyanobacteria belonging to the genusSynechococcusare described. Unicellular cyanobacteria are suspected to be important primary producers in estuarine and marine waters. One isolate (P-11-16) fluoresces red and forms green colonies. The other isolate (P-11-17) fluoresces orange and forms red colonies. Their ultrastructure is very similar to other isolates ofSynechococcusexcept that spinae are formed and are attached to an outer wall layer not found in previously described species. The spinae are straight-walled cylinders, not flared at the base, are 44.0–65.0 nm in diameter, and range up to 2.7 μm in length. Substructure of the spinae wall consists of either material organized into stacks of rings or a strand of material helically coiled at a low (1–6°) angle. Such material yielded a 6.0–9.2 nm cross-banding periodicity. Substructure of the rings or strand appeared to consist of bar-shaped, repeating units as seen in negatively stained material.Other procaryotic cell types with spinae, which were isolated from unincubated, natural seawater, are described.

ISSN:0008-4166    

DOI:10.1139/m81-049

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Forty strains of motileAeromonaswere isolated from healthy and diseased fish. These strains were identified asA.hydrophilaorA.sobria. It was found that only strains ofA.hydrophilaproduced a dermonecrotic factor and two zones of hemolysis on blood agar. All the strains ofA.sorbriatested and 72% of theA.hydrophilawere enterotoxigenic. Finally, we observed that onlyA.hydrophilastrains could regularly produce hemolysin at 10 °C.

ISSN:0008-4166    

DOI:10.1139/m81-050

出版商:NRC Research Press    

年代:1981

数据来源: NRC