摘要:

Clostridia were isolated from marine sediments collected in Puget Sound in the State of Washington. Sampling stations varied in depth from 10 to 240 m and sediment types varied from sand and gravel to reduced mud. Counts of bacteria growing both aerobically and anaerobically at 30 °C were made. Aerobic and anaerobic counts were 1.21 to 16.9 × 104and 0.73 to 23.5 × 104 cells/ml of sediment–water slurry respectively. About 30% of the bacteria growing anaerobically were obligate anaerobes and identified as Clostridia. The identified Clostridia fell into 12 groups. The first three groups, containingClostridium perfringens,C.bifermentans, andC.novyi, made up 76% of the isolates.The results show a variety of species of mesophilic Clostridia in marine sediments withC.perfringensisolated in the highest numbers.

ISSN:0008-4166    

DOI:10.1139/m74-001

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Strains with cytoplasmically and nuclearly inherited antibiotic-resistant markers were tested for cross resistance to diverse inhibitors of mitochondrial function. Five independently isolated nuclear markers were observed to result in resistance to chloramphenicol, tetracycline, oligomycin, antimycin A, carbonylcyanide-m-chlorophenylhydrazone, and triphenylmethylphosphonium bromide; these same strains were sensitive to erythromycin, neomycin, and ethidium bromide. In contrast, 11 strains carrying cytoplasmically inherited resistance markers were not cross resistant to any unrelated chemical inhibitors. It is suggested that the nuclear mutations are expressed as general membrane mutants whereas mitochondrial DNA codes for more specific mitochondrial functions.

ISSN:0008-4166    

DOI:10.1139/m74-002

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The morphology of the photosynthetic bacteriumRhodopseudomonas acidophilastrain P18aF1 1.2 has been investigated with the electron microscope. The cells grow by budding, the sessile buds eventually separating from the mother cells by constriction. In some dividing stages a belt-like structure was observed in the zone of division. Motile cells possess a subpolar tuft of unsheathed flagella. At the site of insertion of the flagella, the cell wall bears 12- to 14-nm wide holes or annuli through which the flagella probably pass. Motile cells readily lose their flagella.The structure of the surface revealed two distinct types: cells with a hexagonally patterned outer layer composed of ring-shaped elements and cells possessing a thick, fibrous capsule. Thin sections showed a well-developed thylakoid system arranged in piles and similar to that of other budding photosynthetic bacteria.The morphology ofR.acidophilahas been compared with that ofR.palustristo show similarities and differences between the two species.

ISSN:0008-4166    

DOI:10.1139/m74-003

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Cells ofVeillonella parvulaM4growing in complex medium with lactate-U-14C as the carbon source were shown to synthesize complex cellular components with lactate carbon. Of the original labeled substrate, 69% of the label appeared in the metabolic end products (acetate, propionate, and CO2) while 25% was distributed among the products of biosynthesis. Of this latter radioactivity, the lipopolysaccharide (LPS2) fraction contained 22% of the total, 6% of which was found in lipid material and 16% in a carbohydrate fraction; this latter material was analyzed and shown to contain labeled glucosamine, galactosamine, galactose, glucose, and ribose. The remaining 2.6% was distributed in DNA (0.6%), cellular amino acids (0.6%), and the extracellular polysaccharide (LPS1) fraction (1.4%). Further analysis showed that this latter fraction was composed of only glucose and galactose. Of the cellular amino acids, arginine, aspartate, glutamate, alanine, and serine were labeled.Since the above results indicated that gluconeogenesis inV.parvulaM4proceeds, at least in part, from lactate, enzyme studies were undertaken with dialyzed crude extracts of the organism to determine the possible route of lactate conversion to P-enolpyruvate. Evidence is presented for the presence of pyruvate kinase and PEP carboxykinase activity in the organism. Since extract preparations produced significant quantities of (32P)ADP, but negligible quantities of (32P)AMP, during assays containing (α-32P)ATP and pyruvate, it was concluded that PEP synthetase or pyruvate, phosphate dikinase are absent in the organism. Thus, from these and previous results, it was concluded that inV.parvulaM4, lactate is converted to P-enolpyruvate via the intermediate, oxaloacetate.

ISSN:0008-4166    

DOI:10.1139/m74-004

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Phage TP50 resembles phage SP50 ofB.subtilisand phage No. 1 ofB.mycoides. Phage PBC1 has a long tail fiber like flagella-specific phages and resemblesB.pumilusphage PBP1. The latter was reexamined but has different dimensions. Heads of phages TP50 and PBP1 are icosahedral. Staining with uranyl acetate causes shrinkage of phage heads. Lysates ofB.cereuscontain cubic, round, or filamentous particles not previously described.

ISSN:0008-4166    

DOI:10.1139/m74-005

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The formation of 3,3′,4,4′-tetrachloroazobenzene from the herbicide propanil (N-(3,4-dichlorophenyl)propionamide), and from 3,4-dichloroaniline was studied in nine soils which varied in pH, percentage of organic matter, clay, and sand. Marked differences were observed in these soils in the amounts of azobenzene formed. In five soils whose pH values fell within a range of pH 4.5 to 5.5, azobenzene was produced from both substrates, while in two soils (Guelph loam and Wendigo loamy sand), azobenzene was only detected from 3,4-dichloroaniline. No azobenzene was detected from either substrate in two additional soils (Belleisle marsh soil (site 22, pH 3.4) and Biz silt loam (pH 6.4)). Air-drying soils, as well as extended periods of storage of freshly collected soils at 4 °C, reduced the formation of azobenzene.

ISSN:0008-4166    

DOI:10.1139/m74-006

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Variations in serine transhydroxymethylase (STHM) activity as a function of the addition of certain nutrilites to the growth medium of cells ofEscherichia coliK12 have been studied. STHM activity was decreased by growth in (a) glycine at high concentrations, and (b) a mixture of C1-derived metabolites (histidine, methionine, adenine, guanine, thymidine) at moderate concentrations. Two hypotheses are explored. The regulation of STHM synthesis can be explained in terms of variations in the intracellular concentration of glycine alone, or together with variations in the concentration of a C1intermediate.

ISSN:0008-4166    

DOI:10.1139/m74-007

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Morphological study of several ectotrophic mycorrhizae of fir (Abies religiosa) showed that they are dichotomic or corralloid, simple or ramified. Four symbiotic fungi were isolated from the mycorrhizae, and judging from the type of infection, they were active and of medium virulence. The macro- and micro-scopic descriptions of each fungal strain show different cultural characteristics as well as different stimulations to the development of the plant.

ISSN:0008-4166    

DOI:10.1139/m74-008

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Aleuriospores ofH.griseaare bounded by a thick, single-layered cell wall differentiated into an outer, electron-dense melanized zone and an inner, hyaline zone. Melanization was initiated at the periphery of the cell wall and progressed inwards towards the cytoplasm. To distinguish between chlamydospores and aleuriospores, the presence of a secondary cell wall in the former and the presence of a partially melanized, single-layered cell wall in the latter might prove a useful criterion in distinguishing between the two spore types. However, before such a distinction is made, similar studies on other aleuriospore-producing species are necessary.

ISSN:0008-4166    

DOI:10.1139/m74-009

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Anaerobic nitrogen fixation in the dark was determined in a natural marine community, developed in a laboratory model ecosystem, at the Oregon State University Marine Science Center in Newport, Oregon. Fixation occurred at a rate of 10 nmol C2H4/cm2per 24 hours. Two different marine N2-fixing bacteria were isolated from seawater and from sediment at the Oregon coast. These bacterial isolates were identified asKlebsiella pneumoniaeandEnterobacter aerogenes. Within a growth period of 100 hK.pneumoniaefixed 3.6 mmol N2per liter andE.aerogenesfixed 1.2 mmol N2per liter. The influence of seawater on N2-fixation activity of these bacteria was compared with that of bacteria from a non-marine origin. The nitrogenase activity of a crude cell-free extract ofE.aerogeneswas dependent upon ATP and Na2S2O4and proceeded at a rate of 3.9 nmol C2H4per minute per milligram protein.

ISSN:0008-4166    

DOI:10.1139/m74-010

出版商:NRC Research Press    

年代:1974

数据来源: NRC