bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical taxonomy and ecology of oligotrophic bacteria isolated from the estuarine environment
Authors: Mallory L. M. , Austin B. , Colwell R. R.
Published: April 2010

Slow-growing bacteria, isolated on nutrient-rich and nutrient-limited media, from Chesapeake Bay water and sediment samples, were examined for 119 biochemical, cultural, morphological, nutritional, and physiological characters. Those bacteria which grow on low nutrient media, termed oligotrophs, a total of 162 strains, were subjected to taxonomic analysis, as a preliminary step in determining their ecological significance. The data for all strains included in the study were examined by computer and the simple matching (SSM) and Jaccard (SJ) coefficients calculated. Clustering was achieved by the unweighted average-linkage method. From sorted similarity matrices and dendrograms, 148 strains, 90% of the total, were recovered in 24 phenetic groups defined at the 80 to 85% similarity level. Only 12 phena could be presumptively identified and these included representatives of Alcaligenes, Corynebacterium, Hyphomicrobium, Hyphomonas polymorpha. Listeria, Nocardia marina, Pedomicrobium, Planococcus citreus, Sphaerotilus, Streptothrix, and Streptomyces. Of the remaining organisms, 10% were unidentified sheathed bacteria. It is concluded that slow-growing bacteria are distributed throughout the estuarine environment and can account for a large proportion of the colonies observed on media after prolonged periods of incubation. The oligotrophic bacteria appear to predominate in areas where the concentration of available nutrients is low and are more characteristic of non-eutrophic aquatic systems.
Preferential inhibition of phosphatidyl ethanolamine synthesis in E. coli by alcohols
Authors: Ingram L. O.
Published: April 2010

Growth of E. coli in the presence of alcohols of chain lengths 1 through 8 results in an increase in the relative abundance of phosphatidyl glycerol. This results primarily from the preferential inhibition of phosphatidyl ethanolamine synthesis. This inhibition appears to be unrelated to membrane fluidity or to changes in fatty acid composition caused by alcohols. Alcohol-induced changes in total fatty acid composition are reflected in all phospholipid classes. Phosphatidyl serine synthetase is proposed as the most likely site for the effects of alcohols on phospholipid synthesis.
The structure of cellulose-producing bacteria, Acetobacter xylinum and Acetobacter acetigenus
Authors: Colvin J. Ross , Sowden L. C. , Leppard Gary G.
Published: April 2010

The structure of the pellicles and cells of the cellulose-producing bacteria, Acetobacter xylinum and Acetobacter acetigenus, was studied by transmission electron microscopy of thin sections and freeze-etch replicas of glucose-stimulated cell suspensions, quiescent cell suspensions, and discrete pellicles. These bacteria have a relatively thin cell wall in section, with several irregular features superimposed on an otherwise simple, Gram-negative morphology. There are no flagella or pili. Unfixed, unextracted cells, viewed as whole mounts, show spherical or ellipsoidal bodies of undetermined composition which disappear after extraction with water or ethanol and propylene oxide. For both species, there are several kinds of cell surface irregularities, some of which are localized protrusions of the cell envelope. A variety of irregularities is seen frequently on cells in the first minutes of glucose incubation, on cells in a discrete pellicle, on quiescent cells, and on starved cells. Immediately after the addition of glucose to cellulose-free cells in suspension culture, fine fibrils appear on and (or) near the cell envelope. The fine fibrils are frequently as small as 3 nm in diameter in both freeze-etch and thin-section preparations and are frequently associated with freshly synthesized cellulose fibrils. Starved cells in suspensions free of (classical) microfibrils sometimes reveal stubs of an extracellular structure whose morphology resembles that of a nascent cellulose fibril.
Phage types of Mycobacterium bovis, substrains of BCG
Authors: Mankiewicz E. , Liivak M.
Published: April 2010

Nineteen substrains of Mycobacterium bovis, strain bacille Calmette–Guérin (BCG) used in laboratories throughout the world for the preparation of BCG vaccines were phage-typed with a battery of mycobacteriophages. The results revealed differences in their susceptibility to phage lysis that allow subdivision of these strains of BCG into two or more phage types.
Enumeration of Clostridium botulinum spores in meats by a pour-plate procedure
Authors: Hauschild A. H. W. , Hilsheimer R.
Published: April 2010

Colonies of Clostridium botulinum could be easily distinguished from meat particles by supplementing Wynne agar with 0.4% egg yolk. The pour-plate method was suitable for enumeration of C. botulinum, provided the medium was covered with a layer of agar containing 0.01% dithiothreitol. Viable counts of heat-treated spores were consistently higher in Wynne agar supplemented with egg yolk (Wynne-EY agar) than in Wynne agar alone.
Pretreatment of hamster cells with phenethyl alcohol alters cell surface glycoproteins and inhibits vesicular stomatitis virus growth
Authors: Ceri Howard , Wright Jim A.
Published: April 2010

Chinese hamster ovary cells cultured in the presence of phenethyl alcohol exhibit obvious changes in cell surface galactose and galactosamine glycoproteins as determined by the galactose-oxidase[3H]borohydride technique and SDS gel electrophoresis. Cells pretreated with phenethyl alcohol (drug was removed before infection) were not as effective as hosts for vesicular stomatitis virus as untreated cultures. A minimum pretreatment time with 0.1% phenethyl alcohol of about 8 h was required before a reduction in virus growth was observed. It is proposed that phenethyl alcohol pretreatment as outlined in this report leads to a modification of the host cellular membrane resulting in the inhibition of virus replication.
Ultrastructure of soybean nodules. II: deterioration of the symbiosis in ineffective nodules
Authors: Bassett B. , Goodman R. N. , Novacky A.
Published: April 2010

Ineffective nodules, formed on Clark-63 soybeans by Rhizobium japonicum strain 8-0 (Iowa), and effective nodules, formed on Clark-63 soybeans by strain 138 (U.S.D.A.), have been examined by electron microscopy at 10–12, 16, and 21 days after seed inoculation. Though strain 8-0 bacteria are able to infect the host cells in a normal manner, infection is followed closely by a progressive deterioration of the symbiosis involving selective autolysis of host cell contents and degeneration of the intracellular bacteria. The host cells, though disrupted, apparently survive the destruction of the bacteria. The observed ultrastructural changes suggest either a suddenly manifested incompatibility between host and rhizobia, or an acute, localized, nitrogen starvation in the infected cells.
Effect of temperature on growth and activity of a methanogenic culture utilising acetate
Authors: Berg L. van den
Published: April 2010

Studies with a methanogenic culture enriched for use of acetic acid showed that this culture had an optimum growth temperature of 35 °C, with only small differences for other temperatures between 30 and 40 °C. The optimum temperature was the same when determined on the basis of biomass production rate during the exponential (log) phase of growth (0.08–0.09 day−1, at 35 °C), amount of biomass present at the end of the log phase (100 mg/ℓ), activity of the biomass (rate of conversion in millimoles per day per milligram (dry wt.) biomass present, 0.08 at end of log phase), or biomass yield (mg (dry wt.) biomass produced per millimole acetic acid converted, 1.0–1.1). Temperatures outside the range 30 to 40 °C caused marked reductions in the above parameters. The maximum temperature for growth was 42–44 °C; the minimum, below 15 °C, the lowest temperature studied. Acetic acid conversion to methane was 0.8–1.0 mol/mol, and was independent of temperature.
The tricarboxylic acid pathway in Desulfovibrio
Authors: Lewis A. J. , Miller J. D. A.
Published: April 2010

Strains of two species of Desulfovibrio were examined for enzymes of the tricarboxylic acid cycle and related pathways. Pyruvate carboxylase (EC 6.4.1.1) is present, and α-ketoglutarate is formed via the tricarboxylic acids. Glutamate, but not succinyl-CoA, arises from α-ketoglutarate. A pathway exists from pyruvate by malic enzyme (EC 1.1.1.39) activity to malate, then fumarate and succinate, again with no evidence of succinyl-CoA formation. The enzymes concerned with metabolism of these dicarboxylic acids show greater activity in the strains that can grow by fumarate dismutation. Glutamate (or glutamine), α-ketoglutarate, and yeast extract repress the enzymes that metabolize the tricarboxylic acids. There appears to be no glyoxylate cycle in Desulfovibrio vulgaris or D. desulfuricans.
The relationship between rhythmic hyphal growth and circadian formation of sclerotia in Sclerotium rolfsii Sacc.
Authors: Kritzman G. , Chet I. , Henis Y.
Published: April 2010

The mycelium of the phytopathogenic fungus Sclerotium rolfsii type 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 of L-[14C]threonine and incorporation of L-[14C]leucine were significantly related to the circadian formation of sclerotia.
Effect of rj1rj1 (non-nodulating) soybeans on nodulation of near isogenic Rj1Rj1 plants in nutrient culture
Authors: Eskew D. L. , Schrader L. E.
Published: April 2010

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 Rj1Rj1 plant grown in association with their rj1rj1 counterparts; these results suggest that a nodulation inhibitor is not associated with the rj1 gene. Reducing the number of plants grown in each pot produced significant (P = 0.05) reductions in nodule number per Rj1Rj1 plant, 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 rj1rj1 plants removed nitrate at a significantly (P = 0.05) slower rate than Harosoy Rj1Rj1 plants, 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 rj1rj1 plant.
Effects of certain cations on the formation and infectivity of Phytophthora zoospores. 1. Effects of calcium, magnesium, potassium, and iron ions
Authors: Halsall D. M. , Forrester R. I.
Published: April 2010

The effects of four cations, Ca2+, Mg2+, K+, and Fe3+, upon the production of zoosporangia by isolates of four species of Phytophthora in 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 in P. cinnamomi and P. drechsleri isolates. 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 of P. cambivora where 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 by P. drechsleri showed 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 when Pinus radiata was used as the host material. The implications and limitations of these results are discussed.
Synchronous sporulation during idiophase development in surface cultures of Rhizopus arrhizus (Fischer)
Authors: Lawler George C. , Weber Darrell J.
Published: April 2010

A method to obtain synchronous sporulation during idiophase development in liquid surface cultures of Rhizopus arrhizus Fischer is described and evaluated for use in studying metabolism associated with asexual sporulation. In this system growth and sporulation are effectively separated. The respiratory pattern indicates three metabolic phases. The first is associated with spore germination; the second, trophophase, with growth; and the third, idiophase, with sporulation. Synchronous sporulation and the occurrence of distinct metabolic phases are taken as indications of fairly uniform cell development in the surface cultures. A photographic method of estimating large numbers of fruiting structures on semisolid medium is also described.
Lipids of antibiotic-resistant and -susceptible members of the Enterobacteriaceae
Authors: Suling William J. , O'Leary William M.
Published: April 2010

Lipids of antibiotic-resistant and related -susceptible strains of the Enterobacteriaceae were extracted with chloroform–methanol and characterized by thin-layer chromatography, densitometry, and fatty acid analysis using gas chromatography. Quantitative differences which correlated with antibiotic resistance existed among the phospholipids and fatty acids. A relatively higher concentration of a ninhydrin-positive phospholipid concomitant with a lower amount of phosphatidylethanolamine was observed in antibiotic-resistant strains of Serratia marcescens. Bacterial strains which harbored R-factor 222 had a higher ratio of phosphatidylglycerol to diphosphatidylglycerol than their respective parent strains while those strains which were resistant to the polymyxins had a lower ratio of these phospholipids. Differences in the relative amounts of certain unsaturated and cyclopropane fatty acids were observed between susceptible and resistant strains. Such differences, however, were dependent upon a particular genus and species.
The effect of the antiherpesvirus drug 5-methoxymethyl-2′-deoxyuridine on the humoral immune response in vivo
Authors: Rouse Barry T. , Babiuk Lorne A. , Gupta V. Sagar
Published: April 2010

5-Methoxymethyl-2′-deoxyuridine (MMUdR), a drug with potent antiviral activity in vitro against Herpes simplex virus, was investigated for its immunosuppressive effects. Doses as high as 2000 mg/kg given daily for 9 days were not immunosuppressive as judged by the fact that treated animals produced normal immune responses to sheep erythrocytes, Brucella bacteria, and Herpes simplex virus.
Structural proteins of a lipid-containing bacteriophage which replicates in Escherichia coli: phage PR4
Authors: Cadden Stephen P. , Sands Jeffrey A.
Published: April 2010

PR4 is a lipid-containing bacteriophage which is able to replicate in Escherichia coli. The virus was labeled with either [14C]leucine and [14C]threonine or H235SO4 and then purified by several rounds of sucrose gradient centrifugation. Autoradiographs showed the virus to be composed of six major protein species with molecular weights (1) 68 000, (2) 47 500, (3) 38 500, (4) 35 000, (5) 20 700, (6) 16 500 daltons. Electropherograms showed protein No. 2 to be the major protein, comprising about 43% of the total weight of viral protein.
The sporulation process in Thermomonospora fusca as revealed by scanning and transmission electron microscopy
Authors: Crawford Don. L. , Gonda Matthew A.
Published: April 2010

The sporulation process in the thermophilic actinomycete Thermomonospora fusca was observed by scanning and transmission electron microscopy. As shown by scanning electron microscopy, spores were produced primarily on aerial hyphae and first appeared as bud-like enlargements at the tips of short multibranched sporophores. Young spores were oval to spherical in shape with a smooth surface. As they matured spores enlarged and developed a rough and globular covering, which was quite fragile and easily detached from the spore. This outer layer, as observed by transmission electron microscopy, was thought equivalent to the sheath of other Thermomonospora species. In cross section, mature spores exhibited a thick spore coat underneath the outer globular layer. This spore coat was usually observed as a single layer, but some spores produced a bilayered coat. No multilayered spore coat or spore cortex was observed in the heat-sensitive spores of T. fusca. They were, therefore, shown to be aleuriospores (microcondia), and not endospores.
Fimbriation in gliding bacteria
Authors: MacRae Thomas H. , Dobson William J. , McCurdy Howard D.
Published: April 2010

Of twenty-two strains of gliding prokaryotes examined, all but three were found to possess polar fimbriae. Fimbriae were not observed on two gliders, while Chloroflexus aurantiacus bore abundant peritrichous fimbriae. In some gliding bacteria, fimbriae were associated with 'holes' surrounded by an electron-transparent collar bearing 12 spike-like projections.
Comparison of colony morphology, salt tolerance, and effectiveness in Rhizobium japonicum
Authors: Upchurch Robert G. , Elkan Gerald H.
Published: April 2010

Four strains of Rhizobium japonicum, two of which produce slimy and non-slimy colony types and two others which produce large and small colony types, were isolated and cloned. All were infective and nodulated Lee soybean host plants. Each colony type was characterized as to its salt sensitivity to Na+ and K+ ions, relative level of symbiotic nitrogen fixation, and relative level of free-living nitrogen fixation. Growth studies performed in the presence of salts demonstrated that the non-slimy or small colony types were sensitive to salt with significantly depressed growth rates and cell yields. Growth rates and cell yields of slimy, large, colony types were relatively unaffected by salt. Both symbiotic and free-living (non-associative) nitrogen fixation analyses (by acetylene reduction) revealed that the non-slimy, small colonies were significantly more effective than slimy, large colonies.
The metabolism of phenylacetic acid by Aspergillus fumigatus ATCC 28282: identification of 2,6-dihydroxyphenylacetic acid
Authors: Yoshizako Fumiki , Chubachi Mitsuo , Nishimura Atsuo , Ueno Teruo
Published: April 2010

Aspergillus fumigatus ATCC 28282 converted phenylacetic acid into a new dihydroxylated compound (2,6-dihydroxyphenylacetic acid) which was identified as 2,6-dimethoxyphenylacetic acid methyl ester. Two other new metabolites have been isolated also and identified as ortho- hydroxyphenylacetic acid and meta-hydroxyphenylacetic acid.
Enterotoxin B production by Staphylococcus aureus under controlled fatty acid nutrition induced by cerulenin
Authors: Altenbern Robert A.
Published: April 2010

Cells of Staphylococcus aureus, strain S-6, can grow in the presence of 100 μg of cerulenin/ml if the basal medium is supplemented with certain saturated or unsaturated fatty acids. The production of enterotoxin B (SEB) is markedly influenced by both the ratio of saturated to unsaturated fatty acid and by the melting point of the unsaturated fatty acid supplement. The results presented suggest that a certain degree of membrane fluidity promotes maximum SEB production and that greater or lesser degrees of membrane fluidity prohibit substantial SEB formation but fail to affect final growth density.
Phage typing of Escherichia coli isolated from chickens
Authors: Bhatia T. R. S.
Published: April 2010

Ten different bacteriophages were isolated from untreated city sewage water. These phages were stable at 57 °C for 40 min. A modified agar layer technique was used to obtain high titre phages. Ninety-four of a stock of 101 cultures of Escherichia coli, which were isolated from inflamed portions of intestines of chickens, were lysed by one or more of these phages.The E. coli of a known serological grouping were phage typed.
Isolation of enterotoxigenic Aeromonas from fish
Authors: Boulanger Y. , Lallier R. , Cousineau G.
Published: April 2010

This paper reports two different enterotoxigenic classes of the genus Aeromonas isolated from fishes. Strains of A. sobria were isolated from healthy fishes only whereas strains of A. hydrophila were isolated from both healthy and moribund fishes. Aeromonas sobria and hydrophila strains produced a cytotoxic factor and were highly proteolytic. Seventy-five percent (75%) of the A. sobria strains produced only one type of hemolysis on 5% blood agar, but 92% of the A. hydrophila produced two types of hemolysis. Enterotoxigenicity of all strains was tested by the rabbit gut loop technique and the suckling mouse test. Most of these Aeromonads were enterotoxigenic. Enterotoxigenic strains appeared to produce two different enterotoxins which were antigenically related, but they seemed to have different mechanisms of action. Enterotoxins of Aeromonas were shown to be antigenically different from those of E. coli.
Ultrastructural characterization of goblet-shaped particles from the cell wall of Flexibacter polymorphus
Authors: Ridgway Harry F.
Published: April 2010

The infrastructure of submicroscopic goblet-shaped particles ('goblets') from the cell wall of the marine-gliding microbe Flexibacter polymorphus was investigated. The goblets, which were partially purified by CsCl density-gradient centrifugation, were rich in protein, exhibiting a single absorption maximum in the ultraviolet at about 276 nm; they also contained a small amount of carbohydrate. As determined by electron microscopy, goblets negatively contrasted with ammonium molybdate were about 30 nm in diameter by 36 nm in length. When viewed in profile, each apparently consisted of five morphologically distinct kinds of components: the C-1, C-2, and C-3 subunits which formed the cup-shaped moiety of the goblet; a globular base unit; and a tubular stem-like structure connecting the cup with the base unit. In addition, a long fiber emerged from the interior of some goblets. The fine structural evidence suggested that goblets may be constructed from three stacked subunit rings (each composed of repeating C-1, C-2, or C-3 protomers) arranged concentrically. X-ray images of a clay model closely resembled electron micrographs of negatively stained goblets, thereby lending support to the proposed structure. It is speculated that goblets function in vivo as macromolecular pores through the outer membrane which mediate extrusion of extracellular fibers, possibly of importance in gliding motility or in attachment of cells to solid surfaces.
A procaryotic intracellular symbiont of the Great Salt Lake brine shrimp Artemia salina (L.)
Authors: Post F. J. , Youssef N. N.
Published: April 2010

Individuals of Artemia salina, the brine shrimp, were captured from the Great Salt Lake, a highly saline (330–340 g ℓ−1 solids content) terminal lake in Utah. Electron microscopy revealed the presence of intracellular procaryotic symbionts in the epithelial lining of the midgut. Fine structure and possible role of the symbiont are discussed.
Mast cell response during the early phase of tuberculosis: an electron-microscopic study
Authors: Ratnam Samuel , Ratnam Shobhitha , Puri B. K. , Chandrasekhar Saroj
Published: April 2010

Guinea pig lungs were infected with Mycobacterium tuberculosis by intratracheal route and examined under electron microscope to investigate the morphological alterations of the organisms, if any, and the response of the host tissue. The bacilli showed no changes in their morphology, while the host tissues revealed several cells containing many electron-dense intracytoplasmic granules. These cells were predominantly seen during the 1st week of infection. The electron-dense bodies of these cells may be the ones observed by earlier workers and suggested to be the altered forms of tubercle bacilli. The present investigation, however, revealed them to be the granules of the mast cells. These cells were observed to respond to tuberculous infection during the first few days by appearing in large numbers crowded with intracytoplasmic granules and soon disintegrating as the result of subsequent degranulation. The above observation is presented and its significance discussed.
Deoxyribonucleic acid base composition of certain species of the genus Bacteroides
Authors: Reddy C. Adinarayana , Bryant M. P.
Published: April 2010

The moles percent guanine plus cytosine content of the DNA (% G + C) of 15 Bacteroides strains representing six species was determined. One group, including three strains of Bacteroides ruminicola, two strains of B. melaninogenicus, two strains of B. succinogenes, and one strain of B. oralis (J1), had a % G + C of 47.6–50.3 and a second group including two strains of B. amylophilus, four strains of fragilis, and one strain of B. succinogenes had a lower % G + C of 40.3–42.7. The taxonomic relationships among these bacteroides species were discussed
Inhibition of Clostridium botulinum types A and B hemagglutinins by sugars
Authors: Dasgupta Bibhuti R. , Sugiyama H.
Published: April 2010

Chromatographically isolated hemagglutinins of Clostridium botulinum types A and B are serologically related but not identical. Of the sugars (5, 6, 12, 18 carbons, some derivatives, L and D forms) tested, only D-galactose and some of its derivatives were inhibitors of these hemagglutinins. o-Nitrophenyl-β-D-galactopyranoside and isopropyl-β-D-thiogalactoside were the most potent inhibitors. The two hemagglutinins were bound tightly by p-aminophenyl-β-D-thiogalactopyranoside coupled to CH-Sepharose 4B. The ligands to which these hemagglutinins bind were determined as the sugars which inhibited the hemagglutinating activity.
Virulence and immunogenicity of types 1 and 3 Neisseria gonorrhoeae in guinea pig subcutaneous chambers
Authors: Arko R. J. , Wong K. H. , Thompson S. E. , Schalla W. O. , Logan L. C.
Published: April 2010

The relative virulence and immunogenicity of type 1 (T1) and type 3 (T3) cells of Neisseria gonorrhoeae were determined by tests with two different kinds of subcutaneous chambers in guinea pigs. In tests with a tissue nonencapsulated (NE) chamber, T1 gonococci were found to be greater than 1000 times more virulent as well as about 1000 times more immunogenic than T3 cells of the same gonococcal strain. However, T1 and T3 cells were found to be equally virulent for a tissue encapsulated (TE) chamber in guinea pigs. Analysis of fluids from the two types of chambers in a complement-dependent bactericidal assay revealed that the NE chamber fluid contained a substantially higher level of complement activity than fluid from TE chambers. The decline in complement level of chamber fluids due to tissue encapsulation was also confirmed by quantitation with rocket gel electrophoresis. A greater resistance of T1 cells to the bactericidal effects of complement appeared to provide a mechanism by which the T1 cells were more virulent than T3 cells for subcutaneous chambers in guinea pigs. Consequently, the NE chamber implant would appear to provide a more relevant environment for studying the virulence, as well as immunological characteristics of gonococcal strains and experimental immunogens.
The formation of macroconidia in dermatophytes following UV irradiation and temperature treatment
Authors: Koshy T. K.
Published: April 2010

The ability of sterile hyphae of Epidermophyton and Microsporum to produce macroconidia was restored by exposing hyphae to ultra violet irradiation followed by prolonged incubation at 35 °C. The four species of Trichophyton used in the present study did not produce macroconidia after such treatments.
Variations quantitatives des principaux constituants cellulaires d'Entomophthora virulenta lors de la sporogénèse
Authors: Latgé J. P. , Bièvre C. De
Published: April 2010

Changes in the relative abundance of cell constituents of Entomophthora virulenta Hall &Dunn were studied during the various differentiation phases leading to the formation of zygospores. The highest total protein (43%) and nucleic acid (5.2% RNA and 0.2% DNA) concentrations were found in the exponential growth phase; these concentrations decreased regularly as the mycelium aged. The amount of lipids was four times larger at the prespore and spore stage (about 25%) than at the exponential mycelial stage. The zygospore contained a very high concentration of chitin (about 17%), three times more than the mycelial concentrations. However, the percentage of polysaccharides without chitin, but including glycogen, was higherin the deceleration phase mycelium (34%) than in the spore (25%). A physiological model of the sexual sporulation of E. virulenta based on these data has been presented.
Physiological and biochemical studies on senescing tap root nodules of soybeans
Authors: Klucas Robert V. , Arp Daniel
Published: April 2010

Senescence of soybean (Glycine max L. Merr.) tap root nodules was investigated by comparing changes in various physiological and biochemical activities with changes in capacity to fix nitrogen. Field-grown Beeson and Calland varieties of soybeans of various ages were sources of tap root nodules. With both varieties, the number of tap root nodules per plant remained constant between 56 and 86 days after planting but fresh weight, dry weight, and mass of tap root nodules increased during this period. Nitrogen (C2H2) fixation by attached tap root nodules was maximum on a fresh weight, dry weight, or nitrogen basis about 56 days after planting for either variety. Metabolic activities of bacteroids as measured by carbon dioxide evolution from glucose and succinate did not appear to vary among nodules of different ages. There was also no indication of mobilization or deposition of iron, molybdenum, calcium, zinc, and nitrate in aging tap root nodules. Nitrate levels in the aerial portion of the plants decreased significantly after the initial decline in acetylene reduction. Nicotinamide deamidase activity in the cytosol and in extracts of bacteroids did not change significantly as tap root nodules aged. However, significant and consistent changes were observed in initial pH values of nodule breis and the initial decline occurred before (Calland) or concurrently (Beeson) with the initial decline of nitrogen fixation.
Numerical taxonomy of heavy metal-tolerant bacteria isolated from an estuary
Authors: Austin B. , Allen D. A. , Mills A. L. , Colwell R. R.
Published: April 2010

A total of 230 strains of metal-tolerant bacteria from water and sediment samples collected in Chesapeake Bay were isolated on a medium containing cobalt, lead, mercury, or molybdenum. In addition, a set of 71 cultures were simultaneously isolated on glucose tryptone yeast extract agar medium without metals. Twenty-three reference strains were also included in the numerical taxonomy study of these bacteria, bringing the grand total of strains examined to 324. All strains were examined for 112 biochemical, cultural, morphological, and physiological characters. The taxonomic data obtained were analyzed by computer and the simple matching (SSM) and Jaccard (SJ) coefficients were calculated. Clustering achieved by unweighted average linkage is presented and. from sorted similarity matrices and dendrograms, 294 strains, i.e., 97% of the total, were recovered in 12 phenetic groups defined at the 75 to 80% similarity level. Among the strains there were nine phena presumptively identified as Bacillus, Erwinia, Mycobacterium, Pseudomonas, and coryneforms. From the results of the taxonomic study, it is concluded that metal tolerance in estuarine water and sediment bacteria occurs among a restricted range of taxa distributed throughout the estuarine environment.
Hepatic lesions and bacterial changes in mice during infection of Fusobacterium necrophorum
Authors: Garcia M. M. , Charlton K. M. , McKay K. A.
Published: April 2010

Liver abscesses were induced in male albino mice within 1 week after intraperitoneal inoculation of viable Fusobacterium necrophorum LA 19 culture. Fusobacteremia was transitory and reached a peak 2 h after inoculation then sharply declined until its disappearance 24 h post inoculation. By contrast, the number of fusobacteria in the liver increased rapidly during the first 4 h post inoculation and continued to do so less rapidly until the last sampling time (48 h post inoculation). There were small or large areas of necrosis, usually surrounded by inflammatory cells, small focal accumulations of lymphocytes, plasma cells, and macrophages in areas of parenchyma with no degenerations, generalized proliferation of Kupffer cells, and a few accumulations of fibrin and leukocytes on the surface. Ultrathin sections of infected liver tissues revealed both intact and partially degraded F. necrophorum cells enclosed in phagocytic and digestive vacuoles of mononuclear cells. The results indicate that macrophages play a key role in the pathogenesis of liver abscesses.
Ultrastructural and immunological demonstration of the nodulation of the European Alnus glutinosa (L.) Gaertn. host plant by the North-American Alnus crispa var. mollis Fern, root nodule endophyte
Authors: Lalonde M. , Quispel A.
Published: April 2010

The inoculation of the European Alnus glutinosa (L.) Gaertn. host plant by a crushed-nodule inoculum, prepared with the North-American Alnus crispa var. mollis Fern, root nodule, was successful. Fluorescein- and ferritin-labelled antibodies, specific against the A. crispa var. mollis root nodule endophyte (Lalonde et al. 1975), demonstrated the identity of this endophyte in the resulting nodules. The nodulation process of this abnormal host–endophyte system was studied by light and electron microscopy. An excretion of host blebs containing electron-dense polysaccharide material, resulting in the formation of exo-encapsulation threads containing presumptive endophytic bacterial cells, was associated with deformed root hairs. Originating from an exoen-capsulation thread, the endophyte penetrates the root hair cell and then migrates as a hypha toward the cortical cells of the root. Its migration in the cortical cells of the primary nodule results in the induction of a lateral root which develops as the true nodule. The ultrastructure of the A. crispa var. mollis endophyte developing in the primary and true nodule of the abnormal A. glutinosa host was similar to the one induced inside its normal A. crispa var. mollis host. The actinomycetal intruder was a branched and septate hypha able to produce septate vesicles. The endophyte was always encapsulated in an electron-dense polysaccharide material surrounded by a host plasma membrane envelope. However, in this abnormal host–endophyte system, the number of primary nodules formed per root system was drastically reduced, and their appearance was delayed by 1 to 2 weeks. The delayed nodules were effective in fixing nitrogen and able to support satisfactory plant growth in a nitrogen-free medium.
Arthrobacter sialophilus sp. nov.; a neuraminidase-producing coryneform
Authors: Tanenbaum S. W. , Flashner M.
Published: April 2010

A new species of Arthrobacter is described for which the name A. sialophilus is proposed. The organism was obtained by elective culture from soil using Collocalia mucoid, and can readily be induced in replacement minimal media with appropriate substrates, to form the enzyme neuraminidase. It undergoes sphere–rod–sphere morphogenesis, is gram-variable, non-motile, aerobic, catalase-positive, oxidase-negative, fails to release acid or gas from saccharides, has a GC content of 56.0 mol % and can grow at temperatures up to 45 °C. The peptidoglycan composition of its spherical form contains neither diaminopimelic acid nor arabinose as components, but does manifest the presence of glycine. Its generation time at 30 °C on tryptone – yeast extract medium is 1.6 h. Accessory growth factors do not appear to be required. The organism, though colorless in the dark, provides a bright yellow water-insoluble pigment after exposure to light. The foregoing combination of properties distinguishes this isolate from other well-described Arthrobacter spp.
Accessory pigment fluorescence for quantitation of photosynthetic microbial populations
Authors: Caldwell Douglas E.
Published: April 2010

The in vivo fluorescence of the primary accessory pigments in purple bacteria (carotenoids), green bacteria (bacteriochlorophyll), green algae (chlorophyll), and cyanobacteria (phycocyanin) was found to be a linear function of cell concentration over three to four orders of magnitude. The lowest cell concentrations detectable were 104 cells/ml for procaryotes and 103 cells/ml for eucaryotes.
The history, biology, and taxonomy of the Cytophaga group
Authors: Christensen Penelope J.
Published: April 2010

The first section of this review covers the important characteristics of the genera Cytophaga and Sporocytophaga. The topics discussed include vegetative cell structure, the spreading habit, and degradation of macromolecules.A historical account of these two genera follows, together with a discussion on the definition of, and species differentiation within the genus Cytophaga, and on the taxonomy of Sporocytophaga.The third section deals with the relationships of the cytophagas with the flavobacteria and includes a brief history of Flavobacterium, reassignation of some species to Cytophaga, differentiation from Cytophaga, and a discussion on the definition of the genus Flavobacterinm.This is followed by a section dealing with the relationship of Cytophaga with the flexibacteria, starting with an introduction to the diversity of flexing organisms and taxonomic developments, and proceeding with the differentiation within the family Cytophagaceae, and species differentiation in Flexibacter.The concluding section includes a proposed redefinition of Cytophaga, a proposal regarding species conservation in this genus, and discussions on the relationship between the cytophagas and the myxobacteria and on the significance of cytophagas in the environment.The characteristics of all described species of Cytophaga, Flexibacter, and relevant flavobacteria are tabulated and a bibliography is presented.
Pigmentation phenotype instability in Myxococcus xanthus
Authors: Burchard Robert P. , Burchard Ann C. , Parish J. H.
Published: April 2010

Cells of Myxococcus xanthus FB2 produce tan or yellow colonies. Subcultures of tan colonies yielded tan and yellow colonies and subcultures of most yellow colonies yielded only yellow colonies. Strain FB2 variants in which the color type is more stable were obtained. Yellow cells were distinguishable from tan by the presence of a pigment(s) with an absorption maximum at 379 nm. Fluctuation Test experiments and the presence of this pigment(s) in liquid cultures of FB2 indicated that tan phenotype cells spontaneously became or segregated yellow cells in liquid culture. The frequency of appearance of yellow cells was increased in low density cultures (<106/ml). The increase cannot be explained by differences in growth rates of the two phenotypes. No evidence that cell–cell contact or culture medium constituents affect the appearance of the yellow phenotype was found. Ultraviolet irradiation of FB2 resulted in an increased proportion of cells producing yellow colonies among the survivors. Greater UV resistance of yellow cells and UV-induced conversion of tan to yellow accounts for this increase. Low level photoreactivation of viability and of the tan phenotype occurred. Incubation of FB2 in medium containing mitomycin C, nalidixic acid, phenethyl alcohol, or at 36.5 °C also resulted in conversion of tan to yellow cells.
L-Methionine as an ethylene precursor in Saccharomyces cerevisiae
Authors: Thomas K. C. , Spencer Mary
Published: April 2010

L-Methionine induced production of ethylene by Saccharomyces cerevisiae growing in lactate medium. The production induced by L-methionine was inhibited by pyruvate, and elevated by glucose. Labeled ethylene was produced when L-[U-14C]methionine, but not [U-14C]glucose, was fed to the yeast. The mutant S. cerevisiae G1332 (ade−, met−) did not produce significant amounts of ethylene unless L-methionine was added. Thus L-methionine acts as a precursor of ethylene in S. cerevisiae. The role of glucose appears to be other than as a precursor.
The electrochemical proton gradient and phenylalanine transport in Escherichia coli irradiated with near-ultraviolet light
Authors: Sprott G. D. , Usher J. R.
Published: April 2010

Irradiation of Escherichia coli with near-ultraviolet (near-UV) light diminished the electrochemical proton gradient and the accumulation of L-phenylalanine. Inhibitors known to collapse the proton gradient and the comparison of two techniques measuring the electrical potential substantiated the estimates made. At several fluences (doses), a linear relationship was observed between the phenylalanine gradient and the combined electrical and chemical potentials (the electrochemical proton gradient), suggesting a close coupling between them. However, additional effects of near-UV light on the phenylalanine permease were not discounted. The combined potentials provided sufficient energy for the observed accumulation of phenylalanine, assuming a proton to amino acid cotransport ratio of 1. An increase in membrane permeability did not contribute to the loss of phenylalanine transport, as shown by an increase in the rate and extent of α-methylglucoside uptake.
Anaerobic degradation of cellulose by mixed culture
Authors: Khan A. W.
Published: April 2010

A mixed culture in which cellulose is capable of being converted to methane and carbon dioxide was obtained from an inoculum procured from a sewage-treatment plant and maintained in a synthetic medium containing tissue paper and an inorganic salt and vitamin mixture. The culture was tested for its ability to degrade 12 different paper and cotton products under batch conditions in 3-ℓ anaerobic fermenters. This culture degraded 6–8 mmol/ℓ per week of cellulose, expressed as glucose equivalents, with total gas yields of 0.3 m3/kg of cellulose degraded. The gas produced contained between 56 and 59% of methane. Maximum cellulose degradation occurred at chemical oxygen demand: nitrogen: phosphorus level of 80:5:1 and was adversely affected by high stirring rate. Also the presence of higher proportions of lignin in cellulose products adversely affected the ability of this culture to degrade cellulose.
The ability of some Yersinia enterocolitica strains to invade HeLa cells
Authors: Lee W. H. , McGrath P. P. , Carter P. H. , Eide E. L.
Published: April 2010

Many types of Yersinia enterocolitica have been isolated from animal, environmental, food, and human sources but their public health significance remains uncertain. Seventy two strains of Y. enterocolitica were tested for their abilities to invade HeLa cells. The typical clinical strains invade HeLa cells like the other species of invasive pathogens. This characteristic remains even in old stock cultures and can be temperature-sensitive like the motility characteristic. With the use of electron micrographs it was demonstrated that the bacteria were truly intracellular and not merely adhering to the HeLa cell membrane. The esculin- and salicin-positive typical clinical strains did not invade HeLa cells. None of 34 food and water isolates were invasive by this test. The negative Y. enterocolitica strains did not adhere to the cells and cause ambiguous results. The HeLa cell test is simple, inexpensive, rapid, and should prove a useful marker for screening the Y. enterocolitica isolates.
Adsorption of Bacillus subtilis bacteriophage PBS 1
Authors: Wilson J. J. , Takahashi I.
Published: April 2010

Bacteriophage PBS 1 adsorbs initially on the flagella of its host, Bacillus subtilis (stage I). The phage can adsorb to both active and inactive flagella. Flagellar attachment is nonspecific as PBS 1 was shown to attach to the flagella of Bacillus species other than the normal host, B. subtilis. The phage particle then quickly moves down the length of the flagellum to its base, the final adsorption site. Flagellar motion is required for flagellar base attachment (stage II). After proper attachment at the flagellar base, the phage tail sheath contracts sending the tail core through the final adsorption site (stage III). The phage DNA is then injected at this site (stage IV). Stage I adsorption does not cause loss of motility in PBS 1 – resistant bacilli. The loss of motility observed upon infection of sensitive cells by PBS 1 may be associated with either stage II or stage III of adsorption.
Role of oxygen in the induction of fermentation in the obligately psychrophilic yeast Leucosporidium stokesii
Authors: Sinclair N. A.
Published: April 2010

Leucosporidium stokesii, an obligately psychrophilic yeast, metabolizes glucose during the initial stages of aerobic growth by aerobic respiration. During later stages of growth and in the presence of excess glucose and limiting oxygen the organism develops a fermentative-type metabolism. Rates of respiration on the other hand remain relatively constant. The change in metabolism occurs only at temperatures which support growth of the organism and does not occur at 25 °C. Resting cells prepared from young glucose-grown cultures can be induced to ferment glucose. The induction process occurs only in the presence of glucose and is inhibited by actidione.
Effect of temperature on the uptake of glucose, gluconate, and 2-ketogluconate by Pseudomonas fluorescens
Authors: Lynch William H. , Franklin Mervyn
Published: April 2010

The effect of temperature on the uptake systems involved with glucose catabolism was studied in a psychrotrophic strain of Pseudomonas fluorescens. The Km values for glucose and gluconate uptake were approximately 1 and 30 μM respectively whether uptake was assayed at 30 or 5 °C. The Km for 2-ketogluconate (2-KG) uptake was approximately 40 μM assayed at 30 °C and 20 μM assayed at 5 °C. Little or no induction of 2-KG uptake was detected in cells grown at 30 °C with glucose or gluconate. High induced levels of 2-KG uptake were observed in cells grown at 5 °C. The induced level of glucose uptake in cells grown at 5 °C with glucose was only one-half the induced level in cells grown at 30 °C with glucose (when activities were compared at the same assay temperature). The effect of low-assay temperature on the activities of these uptake systems was most pronounced for gluconate. When the assay temperature was decreased from 30 to 5 °C, uptake activity decreased 12-fold, 6-fold, and 5-fold for gluconate, glucose, and 2-KG, respectively. Because of the differential effect of temperature on the induction of glucose uptake and on the activity of glucose, gluconate, and 2-KG uptake, the major uptake activity measured in cells grown at 5 °C with glucose or gluconate was through 2-KG. Glucose and 2-KG appeared to inhibit significantly gluconate uptake and (or) catabolism which might promote the continued oxidation of gluconate to 2-KG at low growth temperatures. The results confirm the lack of glucose or gluconate catabolism by the direct oxidative non-phosphorylated pathway through 2-KG at higher growth temperatures and the major function of this pathway at lower growth temperatures.
A simple method for the inactivation of St. Louis encephalitis virus preparations for immunofluorescent microscopy
Authors: Yabrov A. , Artsob H. , Spence L.
Published: April 2010

A study was made of different treatments for the inactivation of St. Louis encephalitis virus in smears prepared for immunofluorescence microscopy. Treatment of infected cells with 0.3% betapropiolactone at 56 °C for 40 min resulted in an inactivated virus suitable for immunofluorescence studies.