bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Drying Medium on Residual Moisture Content and Viability of Freeze-Dried Lactic Acid Bacteria
Authors: de Valdez Graciela F. , de Giori Graciela S. , de Ruiz Holgado Aida P. , Oliver Guillermo
Published: January 2020

The effect of various substances on the relationship between residual moisture content and the viability of freeze-dried lactic acid bacteria has been studied. Compounds such as polymers, which display considerable ability in displacing water, showed no protective action during freeze-drying. Adonitol, on the other hand, produced the smallest change in water content at various times during drying and allowed the highest rate of survival.
Fruiting Body Formation from Regenerated Mycelium of
Pleurotus ostreatus
Protoplasts
Authors: Magae Yumi , Kakimoto Yohichi , Kashiwagi Yutaka , Sasaki Takashi
Published: January 2020

Fruiting bodies were induced from mycelium regenerated from
Pleurotus ostreatus
protoplasts. Mycelia originated from protoplasts conformed to parental strain mycelia in morphology. Six strains selected at random from the dikaryotic regenerants were able to form normal fruiting bodies, yielding 18% more than the parent.
Improved Fixation of Cellulose-Acetate Reverse-Osmosis Membrane for Scanning Electron Microscopy
Authors: Kutz S. M. , Bentley D. L. , Sinclair N. A.
Published: January 2020

Fixation of cellulose-acetate membranes with either glutaraldehyde-osmium tetroxide or glutaraldehyde-ruthenium tetroxide resulted in extensive electron beam damage. Beam damage was eliminated and the bacterial surface structure was preserved, however, when cellulose-acetate membranes were fixed with glutaraldehyderuthenium tetroxide and treated successively with thiocarbohydrazide and osmium tetroxide.
Thymidine Incorporation by Free-Living and Particle-Bound Bacteria in a Eutrophic Dimictic Lake
Authors: Lovell Charles R. , Konopka Allan
Published: January 2020

The percentage of [
methyl
-
3
H]thymidine incorporated into samples from a dimictic eutrophic lake and retained on polycarbonate membranes of 3.0-, 1.0-, and 0.2-μm pore size was studied in a lake with filamentous cyanobacteria as the dominant phytoplankton type throughout the period of thermal stratification. Water samples were also examined by epifluorescence microscopy for evidence of algal senescence and bacterial colonization of intact and damaged cyanobacterial filaments. A small percentage (2 to 20%) of bacterial activity was retained by filters with pore sizes ≥ 1 μm in epilimnetic samples. Epilimnetic samples also had a small percentage of cyanobacterial filaments, either intact or damaged, which were visibly colonized by bacteria in summer and fall samples. A significant proportion (20 to 35%) of bacterial activity was retained by filters with pore sizes ≥ 1 μm in samples collected from the metalimnion and hypolimnion during late summer and fall. The proportion of damaged cyanobacterial filaments was higher in these samples than in those from the epilimnion or from those obtained early in the summer. Furthermore, the filaments in these samples were more heavily colonized by bacteria. Overall, particle-bound production accounted for only 2 to 19% of total bacterial production from April to August in all water layers. It appears that the supply of colonizable particles (damaged cyanobacterial filaments) is an important factor affecting the level of particle-bound bacterial activity in this lake.
Effect of pH, temperature, and potassium sorbate on amino acid uptake in Salmonella typhimurium 7136
Authors: Tuncan E U , Martin S E
Published: January 2020

The effect of sorbate on L-serine and L-histidine uptake in Salmonella typhimurium was studied at various pH levels, temperatures, and amino acid and sorbate concentrations. Low pH had an apparent synergistic effect on amino acid uptake inhibition caused by sorbate. The relationship between sorbate concentration and the amount of amino acid uptake inhibition was not linear. Compared with L-histidine, L-serine uptake was more sensitive to changes in pH, temperature, and sorbate concentration. Various degrees of amino acid uptake inhibition by sorbate may be related to differences between amino acid transport systems. The results of this study suggest that sorbate acts as a noncompetitive inhibitor of amino acid uptake in S. typhimurium.
Modulation of Acetone-Butanol-Ethanol Fermentation by Carbon Monoxide and Organic Acids
Authors: Datta Rathin , Zeikus J. G.
Published: January 2020

Metabolic modulation of acetone-butanol-ethanol fermentation by
Clostridium acetobutylicum
with carbon monoxide (CO) and organic acids is described. CO, which is a known inhibitor of hydrogenase, was found to be effective in the concentration range of dissolved CO corresponding to a CO partial pressure of 0.1 to 0.2 atm. Metabolic modulation by CO was particularly effective when organic acids such as acetic and butyric acids were added to the fermentation as electron sinks. The uptake of organic acids was enhanced, and increases in butyric acid uptake by 50 to 200% over control were observed. Hydrogen production could be reduced by 50% and the ratio of solvents could be controlled by CO modulation and organic acid addition. Acetone production could be eliminated if desired. Butanol yield could be increased by 10 to 15%. Total solvent yield could be increased 1 to 3% and the electron efficiency to acetone-butanol-ethanol solvents could be increased from 73 to 78% for controls to 80 to 85% for CO- and organic acid-modulated fermentations. Based on these results, the dynamic nature of electron flow in this fermentation has been elucidated and mechanisms for metabolic control have been hypothesized.
Metabolites and biodegradation pathways of fatty alcohol ethoxylates in microbial biocenoses of sewage treatment plants
Authors: Steber J , Wierich P
Published: January 2020

The biodegradation of fatty alcohol polyglycol ethers was studied by analyzing the 14C-labeled intermediates isolated from the effluent of a model continuous-flow sewage treatment plant after dosage of either alkyl- or heptaglycol-labeled stearyl alcohol ethoxylate (SA-7EO). In each case, uncharged and carboxylated (mainly dicarboxylated) polyethylene glycols constituted the most prominent metabolites. The results indicate that there is a faster degradation of the alkyl than the polyethylene glycol moiety and that there are two distinct primary degradation mechanisms acting simultaneously in microbial biocenoses: intramolecular scission of the surfactant as well as omega- and beta-oxidation of the alkyl chain. Characterization of the bulk of 14C-labeled metabolites as a homologous series of neutral and acidic polyglycol units and identification of several C2-fragments accounted for the depolymerization of the hydrophilic part of the surfactant by stepwise cleavage of ether-bound EO units; from additional degradation studies employing either neutral or carboxylated 14C-labeled polyethylene glycols as model metabolites, it was concluded that hydrolytic as well as oxidative cleavage of C2-units is involved. Most of the identified low-molecular-weight 14C-labeled acids suggest an ultimate degradation of EO monomers by the oxidative dicarbonic acid cycle or the glycerate pathway or both. In addition, the finding of considerable amounts of oxalic and formic acids allow consideration of an additional mineralization route via glyoxylic, oxalic, and formic acids. The simultaneous action of different degradation mechanisms indicates the involvement of several distinct bacterial groups in the biodegradation of fatty alcohol ethoxylates under environmental conditions.
Microbiological hydroxylation of estradiol: formation of 2- and 4-hydroxyestradiol by Aspergillus alliaceus
Authors: Williamson J , Van Orden D , Rosazza J P
Published: January 2020

Microorganisms known to hydroxylate alkaloids, amino acids, and aromatic substrates were examined for their potential to hydroxylate 17 beta-estradiol and estrone. Thin-layer chromatography of fermentation extracts revealed a wide range of steroid products. Aspergillus alliaceus (UI 315) was the only culture capable of producing good yields of catechol estrogens with 17 beta-estradiol. The organism also transformed estrone but not to catechol products. Analytical experiments with high-performance liquid chromatography revealed that A. alliaceus formed 4- and 2-hydroxyestradiol with yields of 45 and 16%, respectively. A preparative-scale incubation was conducted in 2 liters of medium containing 1 g of 17 beta-estradiol as substrate. 4-Hydroxyestradiol was isolated and identified by proton nuclear magnetic resonance and high-resolution mass spectrometry. Ascorbic acid was added to microbial reaction mixtures as an antioxidant to prevent the decomposition of unstable catechol estrogen metabolites. The microbial transformation of 17 beta-estradiol by A. alliaceus provides an efficient one-step method for the preparation of catechol estrogens.
Insect Feeding Deterrents in Endophyte-Infected Tall Fescue
Authors: Johnson M. C. , Dahlman D. L. , Siegel M. R. , Bush L. P. , Latch G. C. M. , Potter D. A. , Varney D. R.
Published: January 2020

The presence of an endophytic fungus,
Acremonium coenophialum
, in tall fescue (
Festuca arundinacea
) deterred aphid feeding by
Rhopalosiphum padi
and
Schizaphis graminum.
Both species of aphid were unable to survive when confined to endophyte-infected tall fescue plants. Feeding deterrents and toxic factors to
R. padi
and
Oncopeltus fasciatus
, large milkweed bug, were primarily associated with a methanol extract obtained when endophyte-infected tall fescue seed was serially extracted with hexane, ethyl acetate, and methanol. The concentrations of pyrrolizidine alkaloids were determined to be 30 to 100 times greater in the methanol extract than in the hexane and ethyl acetate extracts.
Effects of sorption on biological degradation rates of (2,4-dichlorophenoxy) acetic acid in soils
Authors: Ogram A V , Jessup R E , Ou L T , Rao P S
Published: January 2020

Three mathematical models were proposed to describe the effects of sorption of both bacteria and the herbicide (2,4-dichlorophenoxy)acetic acid (2,4-D) on the biological degradation rates of 2,4-D in soils. Model 1 assumed that sorbed 2,4-D is not degraded, that only bacteria in solution are capable of degrading 2,4-D in solution, and that sorbed bacteria are not capable of degrading either sorbed or solution 2,4-D. Model 2 stated that only bacteria in the solution phase degrade 2,4-D in solution and that only sorbed bacteria degrade sorbed 2,4-D. Model 3 proposed that sorbed 2,4-D is completely protected from degradation and that both sorbed and solution bacteria are capable of degrading 2,4-D in solution. These models were tested by a series of controlled laboratory experiments. Models 1 and 2 did not describe the data satisfactorily and were rejected. Model 3 described the experimental results quite well, indicating that sorbed 2,4-D was completely protected from biological degradation and that sorbed- and solution-phase bacteria degraded solution-phase 2,4-D with almost equal efficiencies.
Anaerobic Degradation of Carrageenan from the Red Macroalga
Eucheuma cottonii
Authors: King Gary M. , Guist G. G. , Lauterbach G. E.
Published: January 2020

Anaerobic degradation of the sulfated polysaccharide carrageenan was investigated by batch digestion of the red macroalga
Eucheuma cottonii.
During a 10-week incubation, ca. 60% of the starting
E. cottonii
biomass was fermented to CO
2
, methane, and volatile fatty acids (predominantly acetate). Carrageenan degradation paralleled the loss of total biomass, suggesting no preferential degradation or preservation. After 10 weeks of incubation, the carrageenan content of the remaining biomass was 51%, as opposed to 61% of the original
E. cottonii
biomass. Carrageenan recovered after 10 weeks of digestion had a lower average molecular weight (319,000 versus 510,000) and formed solutions with considerably lower viscosities than did intact carrageenan. The percent C and percent N content of the particulate material in the digestors increased over time, probably as a result of microbial growth. In contrast, the percent S content decreased continuously; the loss of sulfur was most likely a result of the hydrolysis of carrageenan. Results from this study indicate that it is not economically viable to process
E. cottonii
simultaneously for hydrocolloids and methane.
Nutrition and Growth Characteristics of
Trichomitopsis termopsidis
, a Cellulolytic Protozoan from Termites
Authors: Odelson David A. , Breznak John A.
Published: January 2020

Putatively axenic cultures of
Trichomitopsis termopsidis
6057, isolated by M. A. Yamin (J. Protozool. 25:535-538, 1978) from the hindgut of
Zootermopsis
termites, apparently contained methanogenic bacteria, inasmuch as small amounts of CH
4
were produced during growth. However,
T. termopsidis
could be “cured” of methanogenic activity by incubation in the presence of bromoethanesulfonate. Both the cured derivative (6057C) and the parent strain (6057) required NaHCO
3
and fetal bovine serum for good growth; the presence of yeast extract in media was stimulatory. Growth of both strains was markedly improved by substituting heat-killed cells of
Bacteroides
sp. strain JW20 (a termite gut isolate) for heat-killed rumen bacteria in media as a source of bacterial cell material. Heat-killed
Bacteroides
sp. strain JW20 was the best of a number of bacteria tested, and under these conditions H
2
was a major protozoan fermentation product. Growth of
T. termopsidis
strains was further improved by co-cultivation in the presence of
Methanospirillum hungatii. M. hungatii
was the best of a number of H
2
-consuming bacteria tested, and under these conditions CH
4
, but not H
2
, was produced, indicating interspecies transfer of H
2
between the protozoa and
M. hungatii.
Both strains of
T. termopsidis
used powdered, particulate forms of cellulose (e.g., pure cellulose, corncob, cereal leaves) as fermentable energy sources, although powdered wood, chitin, or xylan supported little or no growth. Cells of the cellulose-forming coccus
Sarcina ventriculi
also served as a fermentable energy source, but these were used poorly as a source of bacterial cell material. The only substantial difference between
T. termopsidis
6057 and 6057C was that the latter grew poorly or not at all with rumen bacteria as a source of bacterial cell material. The improved growth of
T. termopsidis
in vitro should facilitate further studies on the cell biology and biochemistry of these symbiotic, anaerobic protozoa.
Transfer of Sucrose-Fermenting Ability and Nisin Production Phenotype among Lactic Streptococci
Authors: Gonzalez Carlos F. , Kunka Blair S.
Published: January 2020

Transfer of sucrose fermentation ability, nisin production, and nisin resistance from
Streptococcus lactis
to
S. lactis
and
Streptococcus lactis
subsp.
diacetylactis
occurred between cells immobilized on nitrocellulose filters in the presence of DNase. Transconjugants were able to act as donors to transfer the Suc-Nis phenotype in subsequent mating. No changes in sensitivity to lytic phage c2 were noted in
S. lactis
transconjugants. However, temperature-independent restriction of lytic phage 18-16 was noted in transconjugants of
S. lactis
subsp.
diacetylactis
18-16. Adsorption studies with phage-resistant transconjugants showed that resistance was not due to lack of adsorption by the lytic phage. Physical evidence for the presence of introduced plasmid DNA was not found in lysates of transconjugants.
Bactericidal properties of a new water disinfectant
Authors: Williams D E , Worley S D , Wheatley W B , Swango L J
Published: January 2020

The N-chloramine compound 3-chloro-4,4-dimethyl-2-oxazolidinone (agent I) has been compared with calcium hypochlorite as to its efficacy as a bactericide for the treatment of water. The study included concentration, contact time, pH, temperature, and water quality as controlled variables. The species of bacteria tested were Staphylococcus aureus, Pseudomonas aeruginosa, and Shigella boydii. In general, for highly pure, demand-free water, calcium hypochlorite was the more rapid disinfectant at a given total chlorine concentration, although for water containing a controlled amount of organic load, agent I was the better disinfectant. The differences in efficacy of each of the two disinfectants can be attributed primarily to their different stabilities in water at various controlled conditions.
L-Phenylalanine and L-tyrosine catabolism by selected Streptomyces species
Authors: Pometto A L , Crawford D L
Published: January 2020

L-Phenylalanine and L-tyrosine were completely catabolized through homogentisate by Streptomyces setonii 75Vi2 but only partially degraded by Streptomyces badius 252, Streptomyces sioyaensis P5, Streptomyces viridosporus T7A, and Streptomyces sp. strain V7. Intermediates of catabolism were confirmed by thin-layer, gas, and high-pressure liquid chromatography. Homogentisate 1,2-dioxygenase was present in all cell extracts.
Spontaneous occurrence of ochratoxin A residues in porcine kidney and serum samples in Poland
Authors: Goliński P , Hult K , Grabarkiewicz-Szczesna J , Chełkowski J , Szebiotko K
Published: January 2020

During the period 1 April 1983 to 31 July 1984, 214,700 swine were processed in a slaughterhouse in Poznań, Poland. Of these pigs, 122 (0.057%) exhibited macroscopical kidney changes typical for mycotoxic porcine nephropathy. Ochratoxin A was found in kidneys from 52 of these pigs. Porcine serum samples not biased for nephropathy were collected at random in the same slaughterhouse. Of 388 samples, 148 exhibited ochratoxin A residues from 1 to 520 ng/ml. Significant increases in nephropathy and ochratoxin A frequencies were observed during the spring of 1984.
Cometabolism of low concentrations of propachlor, alachlor, and cycloate in sewage and lake water
Authors: Novick N J , Alexander M
Published: January 2020

Low concentrations of propachlor (2-chloro-N-isopropylacetanilide) and alachlor [2-chloro-2',6'-diethyl-N-(methoxymethyl)acetanilide] were not mineralized, cycloate (S-ethyl-N-ethylthiocyclohexanecarbamate) was slowly or not mineralized, and aniline and cyclohexylamine were readily mineralized in sewage and lake water. Propachlor, alachlor, and cycloate were extensively metabolized, but the products were organic. Little conversion of propachlor and alachlor was evident in sterilized sewage or lake water. The cometabolism of propachlor was essentially linear with time in lake water and was well fit by zero-order kinetics in short periods and by first-order kinetics in longer periods in sewage. The rate of cometabolism in sewage was directly proportional to propachlor concentration at levels from 63 pg/ml to more than 100 ng/ml. Glucose but not aniline increased the yield of products formed during propachlor cometabolism in sewage. No microorganism able to use propachlor as a sole source of carbon and energy was isolated, but bacteria isolated from sewage and lake water metabolized this chemical. During the metabolism of this herbicide by two of the bacteria, none of the carbon was assimilated. Our data indicate that cometabolism of these pesticides takes place at concentrations of synthetic compounds that commonly occur in natural waters.
Plasmid-mediated degradation of dibenzothiophene by Pseudomonas species
Authors: Monticello D J , Bakker D , Finnerty W R
Published: January 2020

The microbial transformation of dibenzothiophene (DBT) is of interest in the potential desulfurization of oil. We isolated three soil Pseudomonas species which oxidized DBT to characteristic water-soluble, sulfur-containing products. Two of our isolates harbored a 55-megadalton plasmid; growth in the presence of novobiocin resulted in both loss of the plasmid and loss of the ability to oxidize DBT. Reintroduction of the plasmid restored the ability to oxidize DBT to water-soluble products. The products resulting from the oxidation of DBT were characterized and included 3-hydroxy-2-formyl benzothiophene, 3-oxo-[3'-hydroxy-thionaphthenyl-(2)-methylene]-dihydrothionaph thene, and the hemiacetal and trans forms of 4-[2-(3-hydroxy)-thianaphthenyl]-2-oxo-3-butenoic acid. The products of DBT oxidation were inhibitory to cell growth and further DBT oxidation. DBT oxidation in our soil isolates was induced by naphthalene or salicylate and to a much lesser extent by DBT and was repressed by succinate.
Determination of the concentration of maltose- and starch-like compounds in drinking water by growth measurements with a well-defined strain of a Flavobacterium species
Authors: van der Kooij D , Hijnen W A
Published: January 2020

The growth kinetics of Flavobacterium sp. strain S12 specialized in the utilization of glycerol, and a number of oligo- and polysaccharides were determined in batch-culture experiments at 15 degrees C in pasteurized tap water supplied with very low amounts of substrates. Kss for the growth on maltotriose, maltotetraose, maltopentaose, and maltohexaose were 0.03 microM or less and below those for glucose (1.5 microM) and maltose (0.16 microM). Kss for starch, amylose, and amylopectin were 8.4, 25.6, and 11.0 micrograms of C per liter, respectively. A yield of 2.3 X 10(7) CFU/micrograms of C on the oligo- and polysaccharides was calculated from the linear relationships observed between maximum colony counts in pasteurized tap water and the concentrations (usually below 25 micrograms of C per liter) of supplied compounds. The maximum colony counts of strain S12 grown in various types of raw water and tap water revealed that raw water contained only a few micrograms of maltose- and starch-like compounds per liter; in tap water the concentrations were all below 1 microgram of C and usually below 0.1 microgram of C per liter. The application of starch-based coagulant aids gave increased concentrations of maltose- and starch-like compounds in the water during treatment, but these concentrations were greatly reduced by coagulation and sedimentation, rapid sand filtration, and slow sand filtration.
Proline-hyperproducing strains of Serratia marcescens: enhancement of proline analog-mediated growth inhibition by increasing osmotic stress
Authors: Sugiura M , Kisumi M
Published: January 2020

Proline-producing strains of Serratia marcescens were more osmotolerant than wild-type strains. Growth inhibition by proline analogs was significantly enhanced by increasing the osmotic stress of the medium. Mutants resistant to azetidine-2-carboxylate were derived from a proline-producing strain, SP126, under a high osmotic condition. One of the mutants, strain SP187, produced 56 mg of L-proline per ml of medium containing sucrose and urea. This amount was ca. 3 times larger than that produced by strain SP126. The intracellular glutamate content which decreased in strain SP126 was restored in strain SP187. The glutamate dehydrogenase level of strain SP187 was 5 times higher than that of strain SP126.
Postharvest production of ochratoxin A by Aspergillus ochraceus and Penicillium viridicatum in barley with different protein levels
Authors: Häggblom P E , Ghosh J
Published: January 2020

The production of ochratoxin A (OA) in barley by Aspergillus ochraceus and Penicillium viridicatum was measured at 12 and 25 degrees C. The grain had been fertilized with various amounts of nitrogen fertilizer (0, 90, or 240 kg/ha) and contained (at crop maturity) 9.1, 10.4, or 12.0% protein, respectively. The production of OA by both fungi increased as the protein concentration increased. Glutamic acid and proline were enriched relative to other amino acids as the protein concentration increased. The differences in OA production could not be explained by a differential effect of protein or amino acids on fungal growth in barley. However, glutamic acid and proline enhanced OA production in liquid cultures of both A. ochraceus and P. viridicatum.
Effects of dissolved organic carbon and second substrates on the biodegradation of organic compounds at low concentrations
Authors: Schmidt S K , Alexander M
Published: January 2020

Pseudomonas acidovorans and Pseudomonas sp. strain ANL but not Salmonella typhimurium grew in an inorganic salts solution. The growth of P. acidovorans in this solution was not enhanced by the addition of 2.0 micrograms of phenol per liter, but the phenol was mineralized. Mineralization of 2.0 micrograms of phenol per liter by P. acidovorans was delayed 16 h by 70 micrograms of acetate per liter, and the delay was lengthened by increasing acetate concentrations, whereas phenol and acetate were utilized simultaneously at concentrations of 2.0 and 13 micrograms/liter, respectively. Growth of Pseudomonas sp. in the inorganic salts solution was not affected by the addition of 3.0 micrograms each of glucose and aniline per liter, nor was mineralization of the two compounds detected during the initial period of growth. However, mineralization of both substrates by this organism occurred simultaneously during the latter phases of growth and after growth had ended at the expense of the uncharacterized dissolved organic compounds in the salts solution. In contrast, when Pseudomonas sp. was grown in the salts solution supplemented with 300 micrograms each of glucose and aniline, the sugar was mineralized first, and aniline was mineralized only after much of the glucose carbon was converted to CO2. S. typhimurium failed to multiply in the salts solution with 1.0 micrograms of glucose per liter. It grew slightly but mineralized little of the sugar at 5.0 micrograms/liter, but its population density rose at 10 micrograms of glucose per liter or higher. The hexose could be mineralized at 0.5 micrograms/liter, however, if the solution contained 5.0 mg of arabinose per liter.(ABSTRACT TRUNCATED AT 250 WORDS)
Effects of four aromatic organic pollutants on microbial glucose metabolism and thymidine incorporation in marine sediments
Authors: Bauer J E , Capone D G
Published: January 2020

The metabolism of D-[U-14C]glucose and the incorporation of [methyl-3H]thymidine by aerobic and anaerobic marine sediment microbes exposed to 1 to 1,000 ppm anthracene, naphthalene, p,p'-dichlorodiphenyltrichloroethane, and pentachlorophenol were examined. Cell-specific rates of [14C]glucose metabolism averaged 1.7 X 10(-21) and 0.5 X 10(-21) mol/min per cell for aerobic and anaerobic sediment slurries, respectively; [3H]thymidine incorporation rates averaged 43 X 10(-24) and 9 X 10(-24) mol/min per cell for aerobic and anaerobic slurries, respectively. Aerobic sediments exposed to three of the organic pollutants for 2 to 7 days showed recovery of both activities. Anaerobic sediments showed little recovery after 2 days of pre-exposure to the pollutants. We conclude that (i) anaerobic sediments are more sensitive than aerobic sediments to pollutant additions; (ii) [3H]thymidine incorporation is more sensitive to pollutant additions than is [14C]glucose metabolism; and (iii) the toxicity of the pollutants increased in the following order: anthracene, p,p'-dichlorodiphenyltrichloroethane, naphthalene, and pentachlorophenol.
Formation of bacterial colonies in successive time intervals
Authors: Ishikuri S , Hattori T
Published: January 2020

By enumerating colonies on a plate in successive equal short intervals of time, we found that the number of colonies formed in individual intervals varied at random and their distribution was approximated by a Poisson series. Based on the result, we derived the equation of colony formation (CF equation). This equation describes the relationship between the cumulative number of colonies and incubation time: N(t) = N infinity (1 - exp[-lambda(t - tr)]) where N(t) is the number of colonies at time t. N infinity, lambda, and tr are parameters, expressing the expected number of colonies on a plate at infinite incubation time, the probability of the occurrence of colony formation in a unit of time, and a retardation time, respectively.
Regulation and butanol inhibition of D-xylose and D-glucose uptake in Clostridium acetobutylicum
Authors: Ounine K , Petitdemange H , Raval G , Gay R
Published: January 2020

Clostridium acetobutylicum exhibited diauxie growth in the presence of mixtures of glucose and xylose. Both glucose- and xylose-grown cells had a glucose uptake activity. On the other hand, growth on xylose was associated with the induction of a xylose permease activity, which was repressed by glucose in xylose-induced cells. The rate of sugar uptake with increasing sugar concentrations showed saturation kinetics with an apparent Km of 1.25 X 10(-5) M for glucose and 5 X 10(-3) M for xylose. Concomitant with the production of solvents, the activities of the glucose and xylose transport systems decreased. Among the main products of fermentation, butanol was shown to be a potent inhibitor of the growth of the organism and of the rate of sugar uptake as well as of sugar incorporation into cell materials. These inhibitory effects of butanol were more pronounced in xylose-grown cells than in glucose-grown cells. Butanol completely inhibited growth at a concentration of 14 g/liter for cultures growing on glucose and 8 g/liter for cultures growing on xylose. Concentrations of 7 and 10.5 g/liter of butanol caused a 50% inhibition of the xylose and glucose incorporations into cell materials. These inhibitory levels of butanol were found in typical glucose or xylose fermentation.
Studies on the Inoculation and Competitiveness of a
Rhizobium leguminosarum
Strain in Soils Containing Indigenous Rhizobia
Authors: Meade James , Higgins Patrick , O'Gara Fergal
Published: January 2020

The competitiveness of a
Rhizobium leguminosarum
strain was investigated at two separate locations in field inoculation studies on commercially grown peas. The soil at each location (sites I and II) contained an indigenous
R. leguminosarum
population of ca. 3 × 10
4
rhizobia per g of soil. At site I it was necessary to use an inoculum concentration as large as 4 × 10
7
CFU ml
−1
(2 × 10
6
bacteria seed
−1
) to establish the inoculum strain in the majority of nodules (73%). However, at site II the inoculum strain formed only 33% of nodules when applied at this (10
7
CFU ml
−1
) level. Establishment could not be further improved by increasing the inoculum concentration even as high as 10
9
CFU ml
−1
(9.6 × 10
7
bacteria seed
−1
). The inoculum strain could be detected at both sites 19 months after inoculation. Analysis by intrinsic antibiotic resistance patterns and plasmid DNA profiles indicated that a dominant strain(s) and plasmid pool existed among the indigenous population at site II. Competition experiments were carried out under laboratory conditions between a dominant indigenous isolate and the inoculum strain. Both strains were shown to be equally competitive.
Epizootiology of avian influenza: effect of season on incidence in sentinel ducks and domestic turkeys in Minnesota
Authors: Halvorson D A , Kelleher C J , Senne D A
Published: January 2020

Sentinel ducks and domestic turkey flocks were monitored for influenza infection during a 4-year period. The onset of infection among ducks was similar each year, occurring in late July or early August. Influenza in turkeys was also shown to be seasonal, but the usual onset was 6 to 8 weeks after the detection of influenza in sentinel ducks. Possible explanations for the delayed infection in turkeys are (i) increased waterfowl activity associated with fledging and congregating in late summer and early fall; (ii) vectors transmitting virus from the waterfowl habitat to poultry farms; (iii) cooler environmental temperature, allowing prolonged virus viability; (iv) cooler surface water temperature, allowing prolonged virus viability; (v) groundwater contamination from contaminated surface water; and (vi) virus adaptation in domestic turkeys before infection is detected. We conclude that ducks are not only a natural reservoir of influenza but also have a seasonal infection that appears to be related to seasonal influenza outbreaks in domestic turkeys in Minnesota. However, only some influenza A virus isolates circulating among waterfowl at any given time appear capable of causing detectable infection in turkeys. It is speculated that the seasonal infection in migratory waterfowl may also be related to seasonal influenza infections in other species including humans.
Rapid, simplified method for production and purification of tetanus toxin
Authors: Ozutsumi K , Sugimoto N , Matsuda M
Published: January 2020

A rapid, simplified method for production and purification of tetanus toxin from bacterial extracts was described. The extracts were prepared by stirring young cells (ca. 45-h culture) of Clostridium tetani in 1 M NaCl-0.1 M sodium citrate, pH 7.5, overnight at 0 to 4 degrees C. The toxin was purified by a combination of (i) ammonium sulfate fractionation (0 to 40% saturation), (ii) ultracentrifugation for removal of particulate materials, and (iii) gel filtration by high-pressure liquid chromatography on a TSK G3000 SW-type column. This method required 6 days as follows: (i) overnight incubation of the seed culture, (ii) 2 days for growing the bacteria for toxin production, (iii) overnight extraction of the toxin from the bacteria, (iv) overnight precipitation of the toxin with ammonium sulfate, (v) 2 h for ultracentrifugation of the ammonium sulfate concentrate of the bacterial extract, and (vi) 1 h for high-pressure liquid chromatography. The minimum lethal dose of the purified toxin preparations for mice was 1.4 X 10(7) to 1.5 X 10(7) per mg of protein and they showed 360 to 390 Lf (flocculating activity) per mg protein and a 280/260 nm absorbance ratio of 2.0 to 2.1. The final recovery of the toxin from bacterial extracts was 90 to 93%. The purified preparations gave a single band of toxin protein with a molecular weight of 150,000 +/- 5,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. On crossed immunoelectrophoresis, the purified toxin preparations gave a single precipitation arc against anti-crude toxin serum.
Characterization of the coliform and enteric bacilli in the environment of calves with colibacillosis
Authors: Plews P I , Bromel M C , Schipper I A
Published: January 2020

In the first part of the present study the coliform and enteric bacilli in the environment of calves with colibacillosis were examined. The occurrence, number, and pathogenic properties of Escherichia coli in barnyard soils were obtained from six cattle ranches. The O and K serogroups of E. coli isolates obtained from the feces of calves with colibacillosis born at these cattle ranches were determined, and their serotypes were compared with the E. coli O and K serotypes found in soils. The results showed a reservoir of potentially pathogenic E. coli in barnyard soils contaminated with bovine feces. For the second part of this study, 6 healthy calves and 51 calves with colibacillosis were studied. The numbers of total aerobic heterotrophic bacteria, total streptococci, fecal streptococci, total coliforms, and fecal coliforms in the feces of calves were determined. In addition, coliform and enteric bacilli from the feces of both healthy and diseased calves were identified, and their indole, methyl red, Voges-Proskauer, citrate (IMViC) types were described. In parallel, the IMViC types of coliform and enteric bacilli isolated from barnyard soils previously contaminated with bovine feces were compared with those isolated from uncontaminated soils. All fecal specimens were also examined for the presence of rotavirus. No significant effect on the numbers of the bacterial types was found. The results suggest that the predominant IMViC types found in the feces of calves with colibacillosis originate from the soil. From this study it is apparent that the occurrence, number, and survival of E. coli in barnyard soils is related to ranch husbandry and sanitary practices.
Mechanism of action of lactostrepcin 5, a bacteriocin produced by Streptococcus cremoris 202
Authors: Zajdel J K , Ceglowski P , Dobrazański W T
Published: January 2020

The mechanism of bactericidal activity of lactostrepcin 5 (Las 5), a bacteriocin produced by Streptococcus cremoris 202, was investigated. Las 5 did not kill protoplasts of sensitive cells, and its activity was decreased about 10-fold after pretreatment of the cells with trypsin, suggesting the involvement of the cell wall in the activity of this bacteriocin. In susceptible cells, the bacteriocin slowed down and then stopped synthesis of DNA, RNA, and protein, although this did not appear to be the primary effect of Las 5 action. Las 5 also inhibited uridine transport in susceptible cells and induced leakage of K+ ions and ATP. Survival of cells treated with Las 5 in phosphate buffer was higher in the presence of K+, CA2+, or Mg2+ ions.
Interaction of
Azospirillum
and
Rhizobium
Strains Leading to Inhibition of Nodulation
Authors: Plazinski Jacek , Rolfe Barry G.
Published: January 2020

Rhizobium-Azospirillum
interactions during establishment of
Rhizobium
-clover symbiosis were studied. When mixed cultures of
Azospirillum
and
Rhizobium trifolii
strains were simultaneously inoculated onto clover plants, no nodulation by
R. trifolii
was observed.
R. trifolii
ANU1030, which nodulated clover plants without attacking root hairs, i.e., does not cause root hair curling (Hac
−
), did not show inhibition of nodulation when inoculated together with
Azospirillum
strains. Isolation of bacteria from surface-sterilized roots showed that azospirilla could be isolated both from within root segments and from nodules. Inhibition of nodulation could be mimicked by the addition of auxins to the plant growth medium.
Autolysis of psychrophilic bacteria from marine fish
Authors: Makarios-Laham I , Levin R E
Published: January 2020

Two psychrophillic bacterial isolates of marine fish origin unable to grow at 20 degrees C or above were found to be distinguishable on the basis of autolysis at elevated temperature in various buffer systems. Isolate OP2 exhibited autolysis at 30 degrees C and above, while isolate OP7 underwent autolysis only at 35 degrees C and above. Tris buffer at pH 7.0 and 8.0 and at 35 degrees C significantly protected isolate OP2 from autolysis and failed to do so with isolate OP7. At pH 5.0, suspension phosphate buffer resulted in significantly greater autolysis of both isolates than did suspension in succinate buffer.
Optimization of Conditions for Production of Channel Catfish Ovary Cells and Channel Catfish Virus DNA
Authors: Colyer Tracey E. , Boyle John A.
Published: January 2020

Medium supplements were examined for their effect on the growth of channel catfish ovary cells. It was found that the usual serum supplement of 10% fetal calf serum could be successfully replaced with a combination of 5% fetal calf serum and a mixture of insulin, transferrin, and selenous acid. It was also found that these cells could be grown in a more efficient manner on microcarrier beads. This type of culture produced 14 times the number of cells per milliliter of total medium used compared with the usual tissue culture flasks used for cell growth. The microcarrier system also provided for greater production efficiency of DNA from channel catfish virus, a virus that infects this cell line.
Transformation of Halogen-, Alkyl-, and Alkoxy-Substituted Anilines by a Laccase of
Trametes versicolor
Authors: Hoff Thomas , Liu Shu-Yen , Bollag Jean-Marc
Published: January 2020

The laccase of the fungus
Trametes versicolor
was able to polymerize various halogen-, alkyl-, and alkoxy-substituted anilines, showing substrate specificity similar to that of horseradish peroxidase, whereas the laccase of
Rhizoctonia praticola
was active only with
p
-methoxyaniline. The substrate specificities of the enzymes were determined by using gas chromatography to measure the decrease in substrate concentration during incubation. With
p
-chloroaniline as the substrate, the peroxidase and the
Trametes
laccase showed maximum activity near pH 4.2. The transformation of this substrate gave rise to a number of oligomers, ranging from dimers to pentamers, as determined by mass spectrometry. The product profiles obtained by high-pressure liquid chromatography were similar for the two enzymes. A chemical reaction was observed between
p
-chloroaniline and an enzymatically formed dimer, resulting in the formation of a trimer. All three enzymes oxidized
p
-methoxyaniline to 2-amino-5-
p
-anisidinobenzoquinone di-
p
-methoxyphenylimine, but only the
T. versicolor
laccase and the peroxidase caused the formation of a pentamer (2,5-di-
p
-anisidinobenzoquinone di-
p
-methoxyphenylimine). Our results demonstrate that in addition to horseradish peroxidase, a
T. versicolor
laccase can also polymerize aniline derivatives.
Effect of deoxynivalenol (vomitoxin) on fertility, pregnancy, and postnatal development of Sprague-Dawley rats
Authors: Morrissey R E , Vesonder R F
Published: January 2020

A diet containing 20 ppm (micrograms/g) of purified deoxynivalenol (DON) was fed to male and female Sprague-Dawley rats for 60 and 15 days, respectively, before breeding. Rats consuming feed amended with DON throughout pregnancy and lactation showed no clinical signs of toxicity, nor did the control or pair-fed control groups. Male rats in the DON treatment group showed no feed refusal but were less efficient than males in control groups in converting feed into body mass. Feed refusal in female rats varied with stage of pregnancy. Before breeding, overall feed consumption was similar in all groups, but in the DON treatment group there was significant feed refusal for the first 2 days. Feed conversion efficiency was reduced in the DON treatment group. Pregnant and lactating rats fed DON-treated feed ate 6% less than did control rats fed solvent-treated feed. Although pair-fed control rats ate 14 to 21% less than rats in the DON treatment group, their body weights were greater than those of the DON group rats throughout most of the feeding trials, indicating that DON has a toxic effect. Only 50% of the matings between DON group rats resulted in pregnancy, compared with 80% in the control groups. There were no differences detected among groups in ratio of male to female pups, survival rate, or average litter number and weight. Pup weight gains in all groups were comparable through postnatal day 14.(ABSTRACT TRUNCATED AT 250 WORDS)
Nitrogen Dynamics in Stream Wood Samples Incubated with [
14
C]Lignocellulose and Potassium [
15
N]Nitrate
Authors: Aumen Nicholas G. , Bottomley Peter J. , Gregory Stan V.
Published: January 2020

Surface wood samples obtained from a Douglas fir log (
Pseudotsuga menziesii
) in a Pacific Northwest stream were incubated in vitro with [
14
C]lignocellulose in a defined mineral salts medium supplemented with 10 mg of N liter
−1
of
15
N-labeled NO
3
−
(50 atom%
15
N). Evolution of
14
CO
2
, distribution and isotopic dilution of
15
N, filtrate N concentrations, and the rates of denitrification, N
2
fixation, and respiration were measured at 6, 12, and 18 days of incubation. The organic N content of the lignocellulose-wood sample mixture had increased from 132 μg of N to a maximum of 231 μg of N per treatment after 6 days of incubation. Rates of [
14
C]lignocellulose decomposition were greatest during the first 6 days and then began to decline over the remaining 12 days. Total CO
2
evolution was also highest at day 6 and declined steadily over the remaining duration of the incubation. Filtrate NH
4
+
-N increased from background levels to a final value of 57 μg of N per treatment. Filtrate NO
3
−
N completely disappeared by day 6, and organic N showed a slight decline between days 12 and 18. The majority of the
15
N that could be recovered appeared in the particulate organic fraction by day 6 (41 μg of N), and the filtrate NH
4
+
N fraction contained 11 μg of
15
N by day 18. The
15
N enrichment values of the filtrate NH
4
+
and the inorganic N associated with the particulate fraction had increased to approximately 20 atom%
15
N by 18 days of incubation, whereas the particulate organic fraction reached its highest enrichment by day 6. Measurements of N
2
fixation and denitrification indicated an insignificant gain or loss of N from the experimental system by these processes. The data show that woody debris in stream ecosystems might function as a rapid and efficient sink for exogenous N, resulting in stimulation of wood decomposition and subsequent activation of other N cycling processes.
Specific uptake rates of amino acids by attached and free-living bacteria in a mesotrophic lake
Authors: Simon M
Published: January 2020

Seasonal and spatial patterns of specific uptake rates of amino acids by bacteria in Lake Constance were studied. The total bacterial population was divided into small (0.2- to 1.0-micron) and large (1.0- to 3.0-micron) free-living bacteria and attached bacteria by fractionated filtration. Data for attached bacteria, received by retention on 3.0-micron-pore Nuclepore filters, were corrected for free-living bacteria in this fraction. Specific uptake rates based on autoradiography were also recorded. Specific uptake rates for attached bacteria ranged from 9.41 X 10(-11) to 6.11 X 10(-8) ng of C h-1 cell-1 and were therefore significantly greater than those for free-living bacteria during most time periods. However, they were not significantly different from those for cells proven to be active by autoradiography. Specific uptake rates for small free-living bacteria ranged between 7.68 X 10(-11) and 4.60 X 10(-9) ng of C h-1 cell-1. They were nearly in the same range of those for large free-living bacteria (5.10 X 10(-11) to 1.07 X 10(-8) ng of C h-1 cell-1), although both fractions exhibited pronounced differences in their seasonal and vertical distributions.
Application of DNA-DNA colony hybridization to the detection of catabolic genotypes in environmental samples
Authors: Sayler G S , Shields M S , Tedford E T , Breen A , Hooper S W , Sirotkin K M , Davis J W
Published: January 2020

The application of preexisting DNA hybridization techniques was investigated for potential in determining populations of specific gene sequences in environmental samples. Cross-hybridizations among two degradative plasmids, TOL and NAH, and two cloning vehicles, pLAFR1 and RSF1010, were determined. The detection limits for the TOL plasmid against a nonhomologous plasmid-bearing bacterial background was ascertained. The colony hybridization technique allowed detection of one colony containing TOL plasmid among 10(6) Escherichia coli colonies of nonhomologous DNA. Comparisons between population estimates derived from growth on selective substrates and from hybridizations were examined. Findings indicated that standard sole carbon source enumeration procedures for degradative populations lead to overestimations due to nonspecific growth of other bacteria on the microcontaminant carbon sources present in the media. Population estimates based on the selective growth of a microcosm population on two aromatic substrates (toluene and naphthalene) and estimates derived from DNA-DNA colony hybridizations, using the TOL or NAH plasmid as a probe, corresponded with estimates of substrate mineralization rates and past exposure to environmental contaminants. The applications of such techniques are hoped to eventually allow enumeration of any specific gene sequences in the environment, including both anabolic and catabolic genes. In addition, this procedure should prove useful in monitoring recombinant DNA clones released into environmental situations.