bluuebunny/crossref_metadata_2025 huggingface dataset:
Utilization of triaryl phosphates by a mixed bacterial population
Authors: Pickard M. A. , Whelihan J. A. , Westlake D. W. S.
Published: April 2010

A mixed bacterial population that has been isolated by enrichment culture is capable of growth on Fyrquel 220, a commercial triaryl phosphate lubricant, as sole carbon source.The mixture was dominated by a yellow, Gram-negative rod which made up greater than 60% of the mixture. However, all attempts to grow this organism in pure culture on triaryl phosphate were unsuccessful. The mixed population was also capable of growth on tri-o-cresyl phosphate, trixylenyl phosphate, and triphenyl phosphate as sole carbon sources.Viable cell numbers increased 20- to 30-fold, reaching a maximum after 72–96 h growth. Only a small portion of the triaryl phosphate was used for growth; the major part was emulsified and remained in the culture medium. No evidence of extracellular enzymes capable of triaryl phosphate degradation could be found in concentrates of the culture supernatant after growth, though traces of what may have been triaryl phosphate breakdown products were observed.Cell-free extracts of the mixed culture catalyzed the release of inorganic phosphate when incubated with Fyrquel 220, tri-o-cresyl phosphate, trixylenyl phosphate, or triphenyl phosphate, indicating the presence of a phosphotriesterase or of a phosphodiesterase of wide specificity.
A mixed bacterial population in a continuous culture with and without kaolinite
Authors: Maigetter R. Z. , Pfister R. M.
Published: April 2010

Chromobacterium lividum and a Pseudomonas sp. were grown in pure and mixed continuous culture with and without the clay-mineral, kaolinite. Irrespective of the growth conditions, C. lividum adhered to the wall of the culture vessel whereas the Pseudomonas sp. showed no such tendency, at least visually. During mixed culture studies, the organism which was initially established in the culture dominated. The ratio between C. lividum and the Pseudomonas sp. was about 20:1 when C. lividum was first established and 1:2 when the Pseudomonas sp. was first grown. The indirect fluorescent antibody technique provided a rapid method for differentiating the mixed cultures when the bacterial concentration was sufficient for microscopic analysis. During both pure and mixed continuous culture studies, the addition of kaolinite reduced the C. lividum but not the Pseudomonas sp. population.
Composition of the capsular polysaccharides of Clostridium perfringens as a basis for their classification by chemotypes
Authors: Paine Clarence M. , Cherniak Robert
Published: April 2010

An analytical procedure, using gas–liquid chromatography, was developed for the identification of the per(trimethylsilyl) ethers of the constituent monosaccharides obtained from the capsular polysaccharides of Clostridium perfringens Hobbs 5, Hobbs 9, Hobbs 10, and NCTC 10578. Qualitative and quantitative differences between the major polysaccharide components enabled the differentiation of the four strains of C. perfringens investigated.
Toxigenic studies with the antibiotic pigments from Serratia marcescens
Authors: Kalesperis G. S. , Prahlad K. V. , Lynch D. L.
Published: April 2010

Prodigiosin, obtained from the bacterium, Serratia marcescens, was extracted in five organic solvents, petroleum ether, chloroform, acetone, ethanol, and methanol, and the fractions were labeled PE-1, C-2, A-3, E-4, and M-5 respectively. The effects of prodigiosin and its fractions on embryogenesis showed the whole pigment and C-2 fraction to be highly toxigenic while other fractions demonstrated toxicities approaching LD50 values of 26–30 μg/egg when dissolved in 100% dimethyl sulfoxide. The E-4 fraction in DMSO was least toxic. Ninety-five percent ethanol proved to be highly toxic at a dose level of 0.1 ml/egg indicating that it was an unsuitable solvent for studies of this nature. Disc-agar diffusion sensitivity studies were performed against E. coli, E. aerogenes, S. aureus, B. subtilis, and P. aeruginosa with prodigiosin and fractions dissolved in 100% DMSO. The solvent was found to have no diffusible bacteriostatic activity in vitro. However, prodigiosin and the ethanol (E-4) and methanol (M-5) fractions produced inhibition zones with every organism tested. Data presented below indicate that prodigiosin extracts have toxigenic effects on chick embryos and inhibit the growth of several species of bacteria.
Stable isotope fractionation by Clostridium pasteurianum. 1.34S/32S: inverse isotope effects during SO42− and SO32− reduction
Authors: McCready R. G. L. , Laishley E. J. , Krouse H. R.
Published: April 2010

During growth on minimal salts – sucrose media supplemented with various concentrations (10−4–10−2 M) of sodium sulfate, Clostridium pasteurianum grew at a normal rate and only evolved sulfide in late stages of growth on 10−2 M SO42−. The evolved sulfide was slightly enriched in 34S as compared to the medium sulfur. On the other hand, sulfide was evolved during growth on all concentrations of sulfite tested. Large normal and inverse isotopic effects were observed in the evolved sulfide during SO32− reductions. In contrast, the intracellular sulphur showed much smaller fractionations. The complexity of the isotopic patterns suggests that a dissimilatory sulfite reductase system may be induced by high concentrations of sulfite.
Soil sterilization effects on in situ indigenous microbial cells in soil
Authors: Labeda D. P. , Balkwill D. L. , Casida Jr. L. E.
Published: April 2010

Soil was sterilized by various procedures, and then the resident microorganisms were physically separated and concentrated from the soil for viewing by transmission electron microscopy as thin sections and frozen-etched preparations. Remaining cell viability in the soil was tested by conventional plating before and after enrichment culture. The soil proved to be sterile after treatment with 60Co radiation, prolonged autoclaving, prolonged dry heat application at 200C, or glutaraldehyde (if followed by subsequent mild heating), and could be considered sterile after OsO4 treatment. Treatment with glutaraldehyde alone, or 160C dry heat for 3 h, did not sterilize the soil. Cellular fine structure was altered or destroyed by the heat treatments, but was not affected to any extent by any of the other treatments including glutaraldehyde followed by mild heating. These findings are considered in relation to the residual biological information observable by electron microscopy in soil samples which have been sterilized to eliminate possible pathogens before handling of the soil. These findings are also considered with the objective of obliterating the fine structure of the indigenous microorganisms during soil sterilization so that electron microscopy studies can be made of microorganisms inoculated into and grown in the presterilized soil.
Membrane mutations and production of enterotoxin B and alpha hemolysin in Staphylococcus aureus
Authors: Altenbern Robert A.
Published: April 2010

Staphylococcus aureus strain S-6, which produces enterotoxin type B (SEB), and strain 10-275, a high toxin-producing mutant derived from S-6, display pronounced differences in dye sensitivity, osmotic stability, and bacitracin sensitivity. Such characteristics are consistent with the concept that strain 10-275 is a membrane mutant of strain S-6. Some membrane mutants of S. aureus strain 14458 exhibit about two- to three-fold increases in SEB production whereas other membrane mutants show about twofold increases in α-hemolysin production. It is suggested that specific and independent membrane mutations control the secretory processes resulting in the extracellular elaboration of these exoproteins.
A volatile factor inducing transmissible lysis in Gaeumannomyces graminis (Sacc.) Arx and Olivier var. tritici Walker
Authors: Sivasithamparam K. , Stukely M. , Parker C. A.
Published: April 2010

Filtered water extract of Gabalong soil with a recent history of take-all in wheat caused lytic plaques to form in agar cultures of a virulent strain of Gaeumannomyces graminis var. tritici. The plaques resembled those produced by Bdellovibrio on plates seeded with bacteria. However, there was no evidence of the presence of bacteria, viruses, or mycoplasmas.The lytic factor was transmissible in culture filtrates to fresh subcultures of the fungus. Exposure of young healthy colonies to sublethal doses of ultraviolet light also induced transmissible lysis. The lytic factor was heat-stable, passed through a 25-nm filter, and was not affected by nuclease (enzymes) or severe irradiation with UV light. It also induced lysis in several other strains of G. graminis. Lysis was always preceded by a growth-stimulatory effect on the fungus.The lytic factor was active as a volatile chemical which induced transmissible lysis and continued to be formed, apparently as a self-perpetuating agent, in lysing cultures of the fungus.
A nutritional and taxonomic survey of Arthrobacter soil isolates
Authors: Hagedorn Charles , Holt John G.
Published: April 2010

One hundred and sixty Arthrobacter soil isolates, four groups of 40 from each of four soil types, and 17 Arthrobacter named strains were characterized on the basis of 203 different nutritional tests performed on each culture. One hundred and twenty-one compounds were examined as sole sources of carbon, 44 compounds as sole sources of nitrogen, 22 carbohydrates for the production of acid, and 16 tests were done for tolerance to various dyes. The four groups of soil arthrobacters differed markedly in acid production from carbohydrates, and in utilization of aliphatic amino acids and aromatic hydrocarbons as sole sources of carbon. The named strains did not exhibit as much nutritional diversity as any of the four groups of soil isolates. The results of the nutritional tests were subjected to a computerized taxonomic analysis. Eighty-four of the isolates were contained in nine separate clusters with 87 to 94% similarity; 39 isolates were contained in five mixed but recognizable clusters with 84 to 86% similarity; 60 isolates were randomly mixed with no recognizable clusters and similarity of 72 to 83%. All clusters were composed of nearly equal numbers of isolates from each of the four soils; the named strains were not found associated with any of the clusters of soil isolates. The results indicated that the diversity of the genus Arthrobacter is not represented by the named species already described, and the possibility of using a series of standardized tests to categorize soil arthrobacters into readily identifiable nutritional groups is discussed.
A morphological study of anaerobic bacteria from the hypolimnia of two Michigan lakes
Authors: Caldwell Douglas E. , Tiedje James M.
Published: April 2010

Dense populations of anaerobic bacteria were found sequentially layered below the thermocline in two eutrophic lakes in southwest Michigan. Phase and electron microscopy of whole cells and thin sections were used to reveal the in situ morphology of the dominant members of the community. The predominant chlorophyll-containing bacteria were identified on the basis of their morphology to be members of the genera Pelodictyon, Prosthecochloris, Clathrochloris, Chlorochromatium, Pelochromatium, Thiopedia, Thiocystis, Thiospirillum, and Chromatium. The natural morphology of these organisms is described and compared with the morphology of reported isolates; the morphology of unisolated genera was compared with previous descriptions of natural samples. Most of the organisms near the sediment–water interface and two from the upper hypolimnion have not been previously described. They have been divided into six distinct groups based on morphology; the morphological features of each group are presented. This approach, based on the morphological uniqueness of the procaryotes present, provides a satisfactory method for grouping members of the hypolimnetic community for ecological studies.
The structure of anaerobic bacterial communities in the hypolimnia of several Michigan lakes
Authors: Caldwell Douglas E. , Tiedje James M.
Published: April 2010

The structure of bacterial communities, the distribution of sulfide and oxygen, bacterio-chlorophyll concentrations, and the temperature profile were determined for the anaerobic hypolimnia of two lakes in southern Michigan. Information from these studies, plus qualitative observations of two other lakes and two ponds over a 4-year period were used to correlate the spatial distribution of the populations, cell size, arrangement of photosynthetic vesicles or lamellae, presence of gas vacuoles or flagella, sulfur deposition, and environmental factors. On the basis of these results, three communities designated as A, B, and C were defined. The upper (A) community consisted of sequentially layered purple sulfur bacteria including two or more of the following genera: Thiopedia, Thiospirillum, Thiocystis, or Chromatium. The middle (B) community consisted of sequential layers of green bacteria from one or more of the following genera: Pelodictyon, Clathrochloris, Chlorochromatium, or Prosthecochloris. The lowest (C) community contained previously unreported gas-vacuolate colorless bacteria 0 to 0.7 m above the sediment. Microstratification (0.1- to 0.2-m layers) of populations was observed within the A and B communities.
A cluster analysis of some bacteria in the water column of Green Lake, Washington
Authors: Lighthart Bruce
Published: April 2010

Mass inoculation and computer clustering techniques were used in an abbreviated procedure to group similar bacteria isolated from four depths in the water column of Green Lake, Washington. Four groups of bacteria were differentiable and were categorized as orange-yellow Flavobacterium–Cytophaga, yellow Flavobacterium–Cytophaga, Vibrio–Aeromonas-, and Pseudomonas-like. Some of the groups were most prevalent incertain sample depths in the water column.
Lipase and esterase formation by psychrophilic and mesophilic Acinetobacter species
Authors: Breuil Colette , Kushner D. J.
Published: April 2010

Acinetobacter O16, a psychrophilic species, produced extracelullar lipase (measured by hydrolysis of olive oil, tributyrin, or β-naphthyl laurate) when grown on a complex medium (peptone plus yeast extract). Most lipase was produced during the logarithmic phase of growth. Very little cell-bound lipase was formed. These cells also produced an esterase (measured by the hydrolysis of β-naphthyl acetate). At first, all esterase was cell bound; significant amounts appeared in the external medium late in growth.Breaking the cells did not increase cell-bound lipase activity. After breaking of the cells, most of the cell-bound lipase and esterase activity was solubilized, even after very high speed centrifugation. No appreciable amounts of these enzymes were released by osmotic shock.Lipase formation was greatly affected by nutrient conditions. Lowering either the yeast extract or the peptone content of the normal complex medium lowered or abolished lipase formation. Esterase activity was lowered to a lesser extent. Cells growing in synthetic amino acid plus vitamin medium or in acid-hydrolyzed casein produced substantial amounts of esterase but no cell-free or cell-bound lipase. However, if sodium taurocholate was added to these media, lipase was produced. Greatest production occurred if a mixture of di- and poly-peptides was also present. Taurocholate also stimulated lipase production in the normal complex medium. Adding Tween 80 or ethanol to the normal complex medium inhibited lipase production. Sodium acetate, oleic acid, olive oil, or Tween 20 added to synthetic media did not affect lipase production.The psychrophile grew more quickly at 30 °C than at 15 or 20 °C but produced more lipase at the lower temperatures. Esterase production was about the same at 20 and 30 °C. A mesophilic Acinetobacter species produced the same amount of lipase and esterase at 20 and 30 °C. The best production of lipase by the psychrophile occurred in standing cultures.
Melanin deposition in the hyphae of a species of Phomopsis
Authors: Ellis D. H. , Griffiths D. A.
Published: April 2010

Hyaline hyphae of Phomopsis become pigmented when exposed to short periods of light. Pigment was deposited in the form of melanin granules both within the cell wall and within mucilaginous excrescences that were developed irregularly over the hyphal surface. Analysis of the pigment showed it to have properties similar to that of "Dopa" melanin and to pigments previously isolated from fungal cell walls. Lysis of both hyaline and pigmented hyphal walls by means of lytic enzymes was minimal. It is suggested that the major role of melanin in this fungus is the protection of cellular organelles from harmful ionizing radiations.
Dual effects of glucose on dicarboxylic acid transport in Kluyveromyces lactis
Authors: Zmijewski Jr. Milton J. , MacQuillan Anthony M.
Published: April 2010

The properties of succinate uptake in succinate-grown Kluyveromyces cells were examined. The rate of succinate transport at 15C exhibits an approximate Vmax of 1.2 μmol × h−1 × mg−1 dry weight of cells and an apparent Km of 18 μM. The uptake process appears to be tightly coupled to metabolism. L-Malate, fumarate, and α-ketoglutarate were the only other dicarboxylates tested, which were found to inhibit succinate transport. The agreement between the order of inhibition of succinate transport by these dicarboxylates and their rates of uptake, as well as the competitive nature of the inhibition are all consistent with the existence of a common carrier system showing specificity for dicarboxylates of the TCA cycle. Cells transferred from succinate to glucose medium rapidly lose their ability to transport succinate. Glucose-grown cells also exhibit an inability to oxidize dicarboxylates or to use them for growth without a very long lag. The dicarboxylate uptake system, therefore, appears to be subject to a strong catabolite repression. The derepression of the succinate transport system requires the presence of succinate, as well as low concentrations of glucose.
Bacteriostasis in soils sterilized by gamma irradiation and in reinoculated sterilized soils
Authors: Davis Robert D.
Published: April 2010

An agar-disc method was used to compare the bacteriostatic properties of five soils with those of samples of the same soils sterilized by gamma irradiation. For three of the soils, bacteriostasis was removed either partially or entirely by sterilization. Bacteriostasis was completely restored to sterile soil by reinoculating it with natural soil. All the reinoculation treatments restored the level of bacteriostasis equally effectively, whatever the origin of the soil used as inoculum.
Changes in cutaneous flora after wet occlusion
Authors: Bibel David J. , LeBrun Joseph R.
Published: April 2010

Aerobic flora from wet-occluded forearms of six volunteers was sampled the day before treatment, on the 3rd day when dressings were removed, and daily, when possible, for 8 days thereafter. Erythema was not present. All bacterial colonies appearing on appropriate dilution plates were identified with the aid of a replica-plating technique. Flora of each individual increased to over 104 colony-forming units/cm2 as a result of wet-occlusion, but counts rapidly fell by about 102 units once dressings were removed. Although similar types of bacteria were found on all subjects, the composition of each individual's flora during the recovery response appeared to be unique. Enterobacteriaceae were found on half the subjects with Enterobacter aerogenes being the most successful colonizer. Besides the expected presence of Baird-Parker Staphylococcus subgroup II, high numbers of subgroup IV and some colonies of subgroup III were also observed. Almost all cutaneous diphtheroids were lipophilic and lipolytic.
Release of cell-bound polygalacturonase and cellulase from mycelium of Rhizoctonia solani
Authors: Lisker N. , Katan J. , Chet I. , Henis Y.
Published: April 2010

Propagules of Rhizoctonia solani grown in modified Czapek's medium containing sodium polypectate or carboxymethyl cellulose as a sole carbon source produced both extracellular and cell-bound polygalacturonase (PG), and cellulase (Cx), respectively. The cell-bound enzymes can be released to various extents by shaking the germinating propagules in solutions of NaCl, KCl, phosphate buffer, Na2EDTA (ethylenediaminetetraacetate), detergents such as Triton X-100 (octyl phenoxypolyethoxyethanol), Tween 80 (polyoxyethylene sorbitan monooleate), Celmusol, and distilled water. Sodium dodecyl sulfate (SDS) inactivated both PG and Cx but did not affect Cx activity in phosphate buffer solution. PG was more easily released by salts from the mycelium of R. solani than Cx. The release of both enzymes was a passive process and was not due to an osmotic effect. The amount of the cell-bound fraction was correlated with the total amount of the extracellular fraction rather than with the mycelial growth. At least one-third of the cell-bound fractions of both enzymes was found to be associated with the cell wall fraction of the mycelium.
Regulation of C4-dicarboxylic acid transport in Bacillus subtilis
Authors: Ghei Om. K. , Kay William W.
Published: April 2010

Various mutant strains of Bacillus subtilis were used to study the induction and regulation of the transport of tricarboxylic acid cycle C4-dicarboxylates. L-Malate was the only physiological inducer and bromosuccinate was a gratuitous inducer of dicarboxylic acid transport in a succinic dehydrogenase deficient mutant.Several mutants were isolated with alterations in the ability to transport dicarboxylic acids. One of these (WK6) was defective in the ability to take up succinate when grown on glutamate minimal medium, whereas another (WK1) was inducible to high levels by extremely low levels of L-malate. α-Ketoglutarate dehydrogenase mutants were unable to take up dicarboxylates because of repression of transport by glutamate and (or) α-ketoglutarate. A mutation which resulted in increased levels of α-ketoglutarate dehydrogenase partially overcame this inhibition. Glutamate did not prevent the induction of dicarboxylic acid transport by L-malate in succinic dehydrogenase mutants but was markedly inhibitory in α-ketoglutarate dehydrogenase mutants.
Deep-sea bacteria: growth and utilization of n-hexadecane at in situ temperature and pressure
Authors: Schwarz J. R. , Walker J. D. , Colwell R. R.
Published: April 2010

A mixed culture of bacteria was obtained from the sediment-water interface of a core sample taken off the coast of Florida at a depth of 4940 m. The mixed culture was found capable of utilizing n-hexadecane as a sole carbon source for growth at the in situ temperature (4C) and pressure (500 atm). The rate of utilization under deep-ocean conditions was found to be much slower than the rate observed at ambient pressure (1 atm) and low temperature (4C).
Le virus de la rubéole. II. Réplication dans les cellules Vero et effets de l'actinomycine D et du cycloheximide
Authors: Payment Pierre , Ajdukovic Djordje , Pavilanis Vytautas
Published: April 2010

Budding at the plasmic membrane is the primary mode of production of rubella virus in Vero cells. Intense cytopathic effect is observed even if only 10% of the cells are infected. Actinomycin D has little effect on the multiplication of rubella virus but cycloheximide inhibits its growth. This inhibition is probably due to the reduction of cellular protein synthesis and not to a direct action of the inhibitors on the virus multiplication. Viral proteins in infected cells have not been demonstrated. The presence of a viral substance inhibiting normal cellular synthesis is discussed. [Journal translation]
Differential uptake and metabolism of sitosterol and cholesterol by Achlya, Pythium, and Phytophthora species
Authors: Hendrix James W.
Published: April 2010

The relative ability of isolates of Achlya bisexualis and A. ambisexualis and isolates of Pythium and Phytophthora to take up and metabolize sitosterol and cholesterol was studied. Species of Pythium and Phytophthora took up cholesterol and sitosterol efficiently, whereas Achlya species took up both sterols inefficiently. Species of Pythium and Phytophthora produced a polar metabolite and esters from sitosterol as they did from cholesterol. Achlya species did not produce the polar metabolite from either sterol. In these experiments Achlya species produced esters only from cholesterol; however, their failure to produce esters from sitosterol may have been due to the higher sitosterol than cholesterol concentration.
The demonstration of transmissible gastroenteritis viral antigens by immunoelectrophoresis and counterimmunoelectrophoresis
Authors: Bohac J. , Derbyshire J. B.
Published: April 2010

Immunoelectrophoresis of alkaline intestinal extracts, or the supematants after precipitation of these extracts with 60% ammonium sulfate, prepared from piglets experimentally infected with the DL or Purdue strains of transmissible gastroenteritis virus, revealed up to three antigens. Two antigens migrated towards the anode, and the third migrated towards the cathode. Antigens with anodal or cathodal mobility were also demonstrated in the same materials by counterimmunoelectrophoresis, and the procedure for counterimmunoelectrophoresis was modified to detect both antigens in a single test.
Propriétés physiques et chimiques des tryptophanases de cinq espèces d'Entérobactériaceae
Authors: Simard C. , Mardini A. , Bordeleau L. M.
Published: April 2010

The molecular weight, sedimentation coefficient, and amino acids composition were determined on five tryptophanases (TPases) from Escherichia coli B and E. aurescens, Shigella alkalescens, and Proteus vulgaris and P. morganii. These TPases have identical sedimentation profile and coefficient (9.6 S), and the same molecular weight (220 000). Each enzyme is constituted of four identical subunits having a molecular weight of 55 000. The amino acids composition of these TPases is very similar, with the exception of P. morganii and P. vulgaris TPases which present significative variations in basic amino acids and tryptophan content. The species differentiation of the coli group cannot be made on their TPase characteristics only, contrary to P. morganii and P. vulgaris which can be differentiated between them and from the coli group. [Journal translation]
Effet du phosphate de pyridoxal sur les triptophanases de cinq espèces d'Entérobactériaceae
Authors: Simard C. , Mardini A. , Bordeleau L. M.
Published: April 2010

Escherichia coli B and E. aurescens, Shigella alkalescens, and Proteus vulgaris et P. morganii tryptophanases (TPases) were studied for the spectral forms of the enzyme.The pH effect on the absorption spectrum and on the enzyme specific activity revealed that the coli group TPases are identical with but differ from Proteus TPases which differ themselves. The coli group TPases attach 4 mol of pyridoxal phosphate (PLP)/mol of enzyme, independently of the pH in the presence of K+ ions, and 9 mol of PLP/mol of enzyme must be reduced to achieve complete inactivation. The Proteus TPases attach 4 mol of PLP/mol of enzyme at PH 6.8, and 3 mol of PLP/mol of enzyme at pH 7.8 in K+ buffer. In P. morganii, 7 mol of PLP/mol of enzyme must be reduced to inactivate the enzyme, whereas P. vulgaris TPase cannot be completely inactivated by this method. These five TPases attach only 3 mol of PLP/mol of enzyme in a Na+ buffer, independently of the pH. [Journal translation]
Observations on the distribution and ecology of Clostridium botulinum type E in Alaska
Authors: Miller Lawrence G.
Published: April 2010

Environmental samples collected along the coastline and from the interior of Alaska were examined for the presence of Clostridium botulinum. Clostridium botulinum type E was detected in soils from 5 of 12 beaches; in 7 of 115 non-coastal soil samples; in sediments from six of eight locales; in gills of salmon from two fishing areas; and in the feces of 1 of 44 colonic samples from marine mammals. The basic biochemical characteristics of the isolates were determined. Tube tests for demonstrating gelatin liquefaction proved insensitive with these strains, whereas a plate test detected gelatinase in all isolates. The presence of multiple nidi and the continual discharge of organic materials into the environment may contribute to the perpetuation of botulinum spores by which foods prepared from marine animals become contaminated. An emphasis should be placed upon the need for measures to reduce environmental contamination, to reduce contamination during food preparation, and to alert continually the population of the hazard wherever botulism is endemic.
Cell size as an indicator of changes in intracellular composition of Azotobacter vinelandii
Authors: Shuler M. L. , Tsuchiya H. M.
Published: April 2010

Cell size, measured electronically, was correlated to changes in cellular composition, number, and morphology of Azotobacter vinelandii OP during batch growth. The effect of a changing abiotic environment on these features of the cell is discussed. For this organism exponential growth was unbalanced growth and cell-size change was a sensitive indicator of this growth pattern. Cell-size measurements have the potential to give a rapid assessment of intracellular compositional changes.
The bacterial degradation of fluoranthene and benzo[a]pyrene
Authors: Barnsley E. A.
Published: April 2010

A gas chromatographic method to determine fluoranthene and benzo[a]pyrene at concentrations close to the limit of their solubility in water was used to identify several species of pseudomonads able to degrade fluoranthene and benzo[a]pyrene. Degradation occurs most rapidly in cultures in the stationary phase, is heat sensitive, requires oxygen, and is enhanced in the presence of cyanide.
Ultrastructure of the Alnus crispa var. mollis Fern. root nodule endophyte
Authors: Lalonde Maurice , Knowles Roger
Published: April 2010

Nitrogen-fixing, field-obtained root nodules of the silky green alder were studied by transmission electron microscopy. The nodule endophyte exhibited a prokaryotic cytology and was present in two forms: the hypha (0.3–1.0 μm), which was branched and septate, and the vesicle (3–5 μm), which was also septate and developed at the parental hypha tip. Bacteria-like cells, previously observed in light microscopy studies, were not seen in the present work. The actinomycete-like endophyte penetrated through the host cell wall and became enveloped by a capsular material (0.1 μm), the whole being enclosed by host membranes. In some host cells, the endophyte appeared to lyse and become a mass of shrunken debris. The fine structure of the Alnus crispa var. mollis root nodule endophyte was found to be similar to that of other non-leguminous root nodule endophytes.
An immunoprecipitin study of the incidence of influenza A antibodies in animal sera in the Ottawa area
Authors: Fyson Raina E. , Westwood John C. N. , Brunner A. H.
Published: April 2010

A survey of over 600 'normal' sera from 14 animal species by immunoprecipitin tests in cellulose acetate using virion antigens revealed a high incidence of precipitating activity against a broad range of influenza A virus strains, particularly A2/Hong Kong/1/68 and A/PR8. However, serum treatments trypsin–heat–periodate, NaIO4, V. cholerae receptor-destroying enzyme (RDE), or kaolin eliminated most precipitating activity, which suggests that it was due to "non-specific" inhibitors of influenza viruses. A resistant minority could not be identified as inhibitor or antibody on this basis.Precipitation of the influenza A major type-specific antigen in virus-soluble antigens by human 7S gamma globulin antibody (IgG), demonstrated to be specific for influenza virus, was established as a reference reaction to identify similar immunoprecipitin reactions occurring between virus-soluble antigens and normal or immune sera. Complement fixation tests provided supplementary evidence for the presence of influenza A antibodies in these sera.Influenza A antibodies were found in only a few sera of six animal species: cat, dog, rabbit, goat, chipmunk, and sheep. Thus the animal species examined in the Ottawa area have not revealed an unequivocal reservoir for human influenza A viruses.
Isolation and chemical characterization of outer envelope of Leptospira pomona
Authors: Zeigler Joseph A. , VanEseltine William P.
Published: April 2010

Cells of Leptospira interrogans serotype pomona harvested from a chemically defined medium were resuspended in 0.01 M phosphate buffer of pH 7.3. Electron microscopy showed that 90 min of exposure effectively ruptured the outer envelope, freeing it from the cells as small flakes. Both zonal centrifugation in sucrose gradients and centrifugation in isopycnic KBr and CsCl gradients could be used to separate the outer envelope from the axial filaments and protoplasmic cylinders. The latter method resulted in higher yields of purified envelope with the particular protocols used. Thin sections of isolated outer envelope showed the same trilaminar structure seen in sections of intact cells. The outer layers were 1.5 nm thick and appeared as single layers of electron-dense particles. The central electron-transparent layer was 2.0–2.5 nm thick and appeared structureless.The gross chemical composition of the purified outer envelope was 47% protein, 27% carbohydrate, and 23% lipid. Colorimetric carbohydrate determinations revealed hexose, pentose, and 6-deoxyhexose; hexosamine was identified during amino acid analysis. Muramic acid, heptose, and 2-keto-3-deoxyoctonate were not detected. Thin-layer chromatography revealed only polar lipids, about 98% phosphatidylethanolamine and 2% lysophosphatidylethanolamine. Fatty acids identified by gas–liquid chromatography were octadecanoic, octadecenoic, hexadecanoic, and hexadecenoic. Amino acid analysis revealed 17 amino acids, histidine and glutamic acid being most abundant. The outer envelope was interpreted to be comparable with the outer double-track layer found in the cell covering of gram-negative eubacteria.
The resistance of Pseudomonas aeruginosa to chloramphenicol
Authors: Ingram J. M. , Hassan H. Moustafa
Published: April 2010

A strain of Pseudomonas aeruginosa, which was resistant to 400 μg/ml of chloramphenicol (CM), was isolated. The generation time of the resistant strain was the same in the presence or absence of CM and similar to that of the parent strain growing in the absence of chloramphenicol. Resistance is eliminated by treatment with acridine dyes, mitomycin C, and sodium dodecyl sulfate, suggesting that resistance may be expressed by a plasmid. The resistant strain does not produce the pigment pyocyanine and the addition of pyocyanine to this strain eliminates the resistance factor. A strain sensitive to CM was isolated. This strain does not produce the enzyme acetyl CoA: chloramphenicol transacetylase whereas the resistant strain does. The sensitive strain accumulates 14C-CM at a greater rate and to a greater extent than the resistant strain grown in the presence of CM. The results suggest that the resistant strain inactivates CM by acetylation and, in addition, develops a "permeability" barrier towards chloramphenicol.
Étude de la stabilité et de la dégradation de la fluorescence dans la technique d'immunofluorescence (FTA-ABS) à l'aide de lasers à impulsions
Authors: Lambert N. G. , Ste-Marie A. R.
Published: April 2010

The use of two pulsed lasers as excitation sources in the immunofluorescent technique FTA-ABS (fluorescent treponemal antibody absorption) shows that excitation of specimens by continuous or long-duration pulses of light (in the order of a millisecond) degrades the fluorescence in such a way that it is impossible to quantify exactly the fluorescent signal or repeat the analysis. Stability of fluorescence can be achieved by very short excitation pulses (in the order of a microsecond) and this fast fluorescent signal can be detected only by an electronic detection and recording system. With such a system, high precision is obtained by elimination of errors by the human eye.
Biological characteristics of an enterotoxin produced by Bacillus cereus
Authors: Spira W. M. , Goepfert J. M.
Published: April 2010

An enterotoxin synthesized during exponential growth by Bacillus cereus produces fluid accumulation in rabbit ileal loops, alters vascular permeability in the skin of rabbits, and kills mice when injected intravenously. All activities are eluted simultaneously from a Sephadex G-75 column and are distinct from the hemolysin and egg yolk turbidity factor of B. cereus. The enterotoxin is a true exotoxin. It interacts with intestinal receptor sites in a highly transient manner in the ileal loop system. Rabbit immune serum produced against the culture fluids from one strain of B. cereus neutralized the three biological activities in all other strains tested except strain B-6-ac for which none of the activities were neutralized.Enterotoxin proved to be unstable under a wide variety of conditions; ionic strength was especially critical. Enterotoxin was most stable in a pH range of 5.0 to 10.0, but lost activity rapidly outside this range. Alkylation provided some protection of enterotoxin activity in crude preparations but failed to protect activity during purification procedures. It did not appear to affect critically the enterotoxin molecule itself, since elution profiles on Sephadex G-75 chromatography were unchanged after alkylation.
Fungitoxicity of 1,4-naphthoquinones to Candida albicans and Trichophyton mentagrophytes
Authors: Gershon Herman , Shanks Larry
Published: April 2010

Twenty-one substituted 1,4-naphthoquinones and five 8-quinolinols and copper(II) chelates were tested for antifungal activity against Candida albicans and Trichophyton mentagrophytes. Compounds containing electron-releasing or weak electron-withdrawing groups in the 2 and 3 positions of the 1,4-naphthoquinone ring were the most active against C. albicans at pH 7.0 in the presence of beef serum in the following order: 2-CH3O = 2,3-(CH3O)2 > 2-CH3 > 2-CH3S > 2-NH2 > 2,6-(CH3)2. For T. mentagrophytes under the same conditions the inhibitory 1,4-naphthoquinones contained the substituents 2-CH3O > 2,3-(CH3O)2 > 2-CH3S > 2-CH3 > 2-CH3(NaHSO3) > 2-NH2 > 2-C2H5S, 3-CH3 > 2,6-(CH3)2 > 2,3-Cl2 > 5,8-(OH)2.
Heterotrophic nutrition of the marine pennate diatom Navicula pavillardi Hustedt
Authors: Lewin Joyce , Hellebust Johan A.
Published: April 2010

Navicula pavillardi Hustedt, a marine, littoral, pennate diatom, can grow in the dark on glutamate or on the complex organic supplements tryptone or yeast extract. Growth on glutamate in the dark took place without an initial lag phase, whereas growth on tryptone began only after a 2-day lag phase that could be abolished by the simultaneous presence of glucose. Lactate inhibited growth in the dark on glutamate, but not photoautotrophic growth. Relatively low concentrations of glutamine inhibited photoautotrophic growth. The observed doubling time for heterotrophic growth on glutamate or tryptone was about 70 h, compared with a doubling time of 24 h under optimal photoautotrophic conditions. Glucose did not decrease the doubling time in the dark on tryptone. The assimilation efficiency for glutamate was 41%. The estimated necessary uptake rate for glutamate to account for the observed heterotrophic doubling time on glutamate was close to those measured with isotope techniques. The kinetic parameters for glutamate uptake, which followed Michelis–Menten kinetics, were Ks = 0.018 mM, and Vmax = 7.0 × 10−10 μmol per cell per minute. Although several amino acids served as sole nitrogen sources for photoautotrophic growth and were demonstrated by the use of isotope techniques to enter the cells, they could not be used as substrates for growth in the dark. Glucose was not taken up to a significant extent except by cells grown in the presence of tryptone. Lactate was taken up only by dark-grown cells. Results of preliminary studies on the metabolic fate of several uniformly labeled amino acids are presented.
Nitrogen fixation in the Rhode River estuary of Chesapeake Bay
Authors: Marsho T. V. , Burchard R. P. , Fleming R.
Published: April 2010

The distribution, seasonal variation, origin, and significance of biological nitrogen fixation has been determined for a Chesapeake Bay estuary using the acetylene reduction technique. Studies over a 15-month period have shown that nitrogen fixation occurs predominantly in the surface intertidal (marsh) and subtidal sediments. Negligible activity was found in surface waters. A marked seasonal variation in nitrogen fixation was observed for intertidal sediments incubated at a standard 20 °C. Average rates of about 37 and 12 ng N/g dry sediment per hour were observed in the late fall months of 1972 and 1973, respectively, and [Formula: see text] dry sediment per hour during other seasons. Peaks of activity were lowered considerably when samples were incubated at ambient temperatures (in situ). Activity in the subtidal sediments was low ([Formula: see text] dry sediment per hour but showed a similar (~twofold) seasonal variation in nitrogen fixation potential. Light–dark and substrate addition experiments suggest that heterotrophic bacteria are the principal agents for nitrogen fixation in sediments. Integrated estimates of nitrogen fixation in the estuary indicate that biological fixation probably accounts for <5% of the total influx of nitrogen into the system. Rates of activity in the intertidal sediments are insufficient to account for the high productivity of marine angiosperms found in the marsh.
Proteolytic activity of Oidiodendron kalrai
Authors: Cino P. M. , Tewari R. P.
Published: April 2010

The physiochemical characteristics of the intracellular proteolytic enzymes of Oidiodendron kalrai, a neuropathogenic fungus, were studied. The organism in the yeast phase was grown in a semisynthetic medium containing 1% tryptone, at 37 °C for 48 h, on a gyrotory shaker. The crude extract was prepared by breaking the cells in a French pressure cell and the proteolytic activity was tested against biological substrates. The cell-free extract hydrolyzed casein, hemoglobin, lactalbumin, gelatin, elastin, collagen, and purified rabbit renal basement membrane to various degrees. Optimal proteolytic activity was observed at pH 6 and at 32 °C. Calcium and EDTA did not affect the enzymatic activity; however, activity was partially inhibited by sulfhydryl-blocking agents and by heat-inactivated horse, calf, and human serum. The extract was totally inactivated by exposure to a temperature of 70 °C for 60 min. Storage at −76 °C or −15 °C for 6 months or at 4 °C for 4 weeks did not affect protease activity.
Role of cell wall topography in conjugation of Schizosaccharomyces pombe
Authors: Streiblová Eva , Wolf A.
Published: April 2010

The surface of the zygotes of Schizosaccharomyces pombe was studied by observing fluorescence following primulin treatment. Conjugation occurred only at the poles. Competence to fuse was independent of actual pole growth and pole ontogeny (old or new pole). The cells were competent to fuse throughout the first three-quarters of the cell cycle. Morphological criteria indicate that cell pairs are not synchronized at the moment of fusion. The length of the G1 phases of individual conjugating cells apparently ranges from 0.1 to 0.7 of the cell cycle duration.
Nitrofurazone-reducing enzymes in E. coli and their role in drug activation in vivo
Authors: McCalla D. R. , Olive P. , Tu Yu , Fan M. L.
Published: April 2010

Earlier work showed that Escherichia coli contains at least two enzymes which reduce nitrofurazone and other nitrofuran derivatives. One of these enzymes is lacking in some nitrofurazone-resistant mutant strains. We now report that there are three separable nitrofuran reductases in this organism: reductase I (mol. wt. ~50 000, insensitive to O2), reductase IIa (mol. wt. ~120 000, inhibited by oxygen), reductase IIb (mol. wt. ~700 000, inhibited by O2).Unstable metabolites formed during the reduction of nitrofurazone by preparations containing reductases IIa and IIb produce breaks in DNA in vitro. In vivo experiments with nitrofurazone-resistant strains, which lack reductase II but contain reductases IIa and IIb, demonstrated that lethality, mutation, and DNA breakage are all greatly increased when cultures are incubated under anaerobic conditions, i.e., conditions such that reductase II is active. These results provide further evidence for the importance of reductive activation of nitrofurazone.
Temperature and pH optima for 21 species of thermophilic and thermotolerant fungi
Authors: Rosenberg S. L.
Published: April 2010

A glucose-containing mineral medium supplemented with 0.01% yeast extract is described upon which all the species of thermophilic and thermotolerant fungi tested will grow. Thirteen of the 21 species do not require the yeast extract supplement for growth.Using this solid, supplemented mineral medium, the pH and termperature optima for growth of all strains were measured. No correlation was found between temperature optimum and pH optimum among members of the group tested.
Concanavalin A as a selective agent in tissue culture for temperature-sensitive hamster cell lines
Authors: Wright Jim A.
Published: April 2010

A novel method for isolating Chinese hamster cell cultures with temperature-sensitive growth properties is described. Concanavalin A can be used as a selective agent in tissue culture to isolate lectin-resistant cell lines which exhibit colony-forming abilities at the nonpermissive temperature relative to the permissive temperature as low as 10−4 to 10−6. A general correlation exists between resistance to the lectin and temperature sensitivity.
Regulation and properties of an invertase from Clostridium pasteurianum
Authors: Laishley E. J.
Published: April 2010

An intracellular invertase was induced in cultures of Clostridium pasteurianum utilizing sucrose as its carbon source for growth. This enzyme synthesis could be repressed by the addition of fructose to a sucrose-growing culture. In contrast, invertase activity was not affected by the addition of glucose to sucrose-growing cells and this enzyme could be induced in a glucose-metabolizing culture by the addition of sucrose.This enzyme was purified 10.5-fold over the induced level from sucrose-grown cells and characterized as an invertase (β-fructofuranosidase, EC 3.2.1.26) by substrate-specificity studies. Invertase had a pH optimum of 6.5 and an apparent Km of 79.5 mM for sucrose, and required high concentration of potassium phosphate for maximum activity. Invertase was completely inactivated by a 2-min heat treatment at 60 °C. This enzyme was strongly inhibited by p-hydroxymercuribenzoate (pCMB) and weakly inhibited by 5,5′-dithiobis(2-nitrobenzoic acid), while cysteine could substantially reverse pCMB inhibition, suggesting that sulfhydryl group(s) were necessary for invertase activity.