bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphate inhibition of secondary metabolism in Serratia marcescens
Authors: Witney F R , Failla M L , Weinberg E D
Published: January 2020

The synthesis of prodigiosin by non-proliferating cells of Serratia marcescens was examined in the presence of a wide range of concentrations of inorganic phosphate (Pi). A high elevation of pigment formation was obtained at less than or equal to 0.3 mM, and a broader but much lower elevation was obtained at 10 to 250 mM Pi. The synthesis of two immediate precursors of the pitment also was inhibited by Pi. The mechanism of action of Pi did not involve changes in pH or accumulation of the trace metal nutrient iron or zinc. Inhibition was most pronounced when Pi was added to the induction system before the onset of pigment formation. The inhibitor also diminished the burst of alkaline phosphatase activity that occurred in the period between the start of induction and appearance of prodigiosin.
New microbial growth factor
Authors: Bok S H , Casida L E
Published: January 2020

A screening procedure was used to isolate from soil a Penicillium sp., two bacterial isolates, and a Streptomyces sp. that produced a new microbial growth factor. This factor was an absolute growth requirement for three soil bacteria. The Penicillium sp. and one of the bacteria requiring the factor, an Arthrobacter sp., were selected for more extensive study concerning the production and characteristics of the growth factor. It did not seem to be related to the siderochromes. It was not present in soil extract, rumen fluid, or any other medium component tested. It appears to be a glycoprotein of high molecular weight, and it has high specific activity. When added to the diets for a meadow vole mammalian test system, it caused an increased consumption of diet without a concurrent increase in rate of weight gain.
Preparation of Specifically Labeled
14
C-(Lignin)- and
14
C-(Cellulose)-Lignocelluloses and Their Decomposition by the Microflora of Soil
Authors: Crawford Don L. , Crawford Ronald L. , Pometto Anthony L.
Published: January 2020

Microbial decomposition of lignocellulose in soil was studied using radioisotope techniques. Natural lignocelluloses containing
14
C in either their lignin or cellulose (glucan) components were prepared by feeding plants
l
-[U-
14
C]phenylalanine or
d
-[U-
14
C]glucose, respectively, through their cut stems. Detailed chemical and chromatographic characterization of labeled lignocelluloses from three hardwood and three softwood species showed that those labeled by the [
14
C]glucose incorporation method contained specifically labeled cellulosic components, whereas those labeled by the [
14
C]phenylalanine incorporation method contained specifically labeled lignin components. Microbial degradation of these differentially labeled lignocelluloses was followed by monitoring
14
CO
2
evolution from selected soil samples incubated with known amounts of radiolabeled lignocelluloses. The lignin components of the six woods were shown to be decomposed in soil 4 to 10 times more slowly than their cellulosic components. These rates of mineralization were comparable to the generalized patterns previously reported in the literature. The present technique, however, was thought to be simpler, more sensitive, and less prone to interference than methods previously available.
Norleucine accumulation by a norleucine-resistant mutant of Serratia marcescens
Authors: Kisumi M , Sugiura M , Chibata I
Published: January 2020

A norleucine-resistant mutant was derived from an isoleucine-valine auxotroph of a leucine accumulator of Serratia marcescens. The norleucine-resistant mutant could accumulate norleucine from norvaline in the medium without the addition of methionine, which antagonized norleucine. This mutant constitutively formed homoserine-O-transsuccinylase.
Occurrence and distribution of bacterial indicators and pathogens in canal communities along the Texas coast
Authors: Goyal S M , Gerba C P , Melnick J L
Published: January 2020

Increased construction of residential canal communities along the southern coastline of the United States has led to a concern about their impact on water quality. Pollution of such dead-end canals is potentially hazardous because of their heavy usage for recreational activities. Coliforms, fecal coliforms, and salmonellae in the surface water and bottom sediments of six selected residential coastal canals were monitored over a period of 17 months. No statistically significant relationship was observed between the organism concentrations and temperature, pH, turbidity, and suspended solids content of water. An inverse relationship between the concentration of indicator organism and salinity of water was found, however, to occur at a 99.9% level of significance. All of the microorganisms studied were found to be present in greater numbers in sediments than in the overlying water, often by a factor of several logs. Heavy rainfall resulted in large increases in the number of organisms in both water and sediment samples. Our results indicate that bottom sediments in the shallow canal systems can act as reservoirs of enteric bacteria, which may be resuspended in response to various environmental factors and recreational activities.
Pyruvate production and excretion by the luminous marine bacteria
Authors: Ruby E G , Nealson K H
Published: January 2020

During aerobic growth on glucose, several species of luminous marine bacteria exhibited an imcomplete oxidative catabolism of substrate. Pyruvate, one of the products of glucose metabolism, was excreted into the medium during exponential growth and accounted for up to 50% of the substrate carbon metabolized. When glucose was depleted from the medium, the excreted pyruvate was promptly utilized, demonstrating that the cells are capable of pyruvate catabolism. Pyruvate excretion is not a general phenomenon of carbohydrate metabolism since it does not occur during the utilization of glycerol or maltose. When cells pregrown on glycerol were exposed to glucose, they began to excrete pyruvate, even if protein synthesis was blocked with chloramphenicol. Glucose thus appears to have an effect on the activity of preexisting catabolic enzymes.
Effect of coumarin on growth and metabolism of Pythium
Authors: Neto F C , Dietrich S M
Published: January 2020

Coumarin concentrations that inhibited growth of Pythium sp. rapidly decreased the rate of incorporation of [14C]glucose into the mycelium. Coumarin also reduced drastically the carbohydrate and protein content of the cytoplasm and, to a lesser extent, the amino acid content and cell wall fraction. Enzymes related to the metabolism of cell wall polysaccharides were not affected during early exposure to the inhibitor. The possible mechanism of coumarin action via inhibition of glucose uptake is discussed in the light of the present findings.
Evidence for incorporation of thymidine into deoxyribonucleic acid in airborne bacterial cells
Authors: Straat P A , Wolochow H , Dimmick R L , Chatigny M A
Published: January 2020

As part of an effort to discover whether bacteria might propagate within airborne particles, we studied the incorporation of thymidine into the trichloroacetic acid-insoluble fraction of airborne cells of Serratia marcescens to seek evidence of the possible formation of new DNA. Two aerosols, one of S. marcescens and another of [3H]thymidine ([3H]dT) suspended in growth medium were caused to aggregate in air just prior to directing the aerosols into rotating-drum aerosol storage chambers. The age of the S. marcescens culture and other conditions for maximizing ([3H]dT) uptake were selected on the basis of prior in vitro trials. With 10-h cultures and addition of 2-deoxyadenosine to the [3H]dT, we showed that [3H]dT is incorporated into the trichloroacetic acid-insoluble fraction of cells recovered 6 h after aerosols were stored under the conditions of high humidity and 30 degrees C. Tests conducted in the same manner with Formalin-killed S. marcescens ruled out the possibility of adsorptive carry-over of [3H]dT. As much as 20 times more activity was found in the trichloroacetic acid-insoluble fraction of live cells than of dead cells.
Comparative Statistical Study of the Cornwall, LKB, and Micromedic Dispensers
Authors: Barbaree J. M. , Habas J. A. , Rossing P. H. , Dobbins J. F.
Published: January 2020

The working precisions of the 5.0-ml-capacity Cornwall, the LKB 2075, and the Micromedic model 25000 dispensers were compared, and the bias of the LKB dispenser was contrasted with that of the Micromedic dispenser. Three technologists used six Cornwall dispensers, three LKB units with four different pumps, and three Micromedic units with six different pumps to dispense (in 1.0-ml amounts) sucrose solution adjusted to match the normal viscosity of serum. Under these conditions, the LKB dispenser was approximately 30% more precise than the Micromedic dispenser, which was approximately four times as precise as the Cornwall dispenser. Although the left pump site of the Micromedic was slightly more precise than the LKB, overall the Micromedic was less precise than the LKB. Moreover, the LKB was easier to use than the Micromedic.
Isolation and characterization of human fecal bacteria capable of 21-dehydroxylating corticoids
Authors: Bokkenheuser V D , Winter J , Dehazya P , Kelly W G
Published: January 2020

It has been known for a decade that human intestinal flora include organisms capable of 21-dehydroxylating corticoids. Yet the identity of the organisms synthesizing 21-dehydroxylase has remained unknown. Using diluted human feces, we determined the prevalence of colonies of 21-dehydroxylating organisms on a variety of media. Isolation from the medium of colonies with the highest prevalence yielded an obligate anaerobe capable of 21-dehydroxylating deoxycorticosterone and tetrahydrodeoxycorticosterone. This transformation could be carried out in a prereduced medium by the microbial culture alone or in an aerobic medium reduced by growth of Escherichia coli. The culture shares many characteristics with Eubacterium lentum, the neotype strain of which elaborated both 21-dehydroxylase and 3alpha-hydroxysteroid dehydrogenase.
Survival of
Vibrio parahaemolyticus
After Chilling in Transport Media: an Explanation for Divergent Findings
Authors: Clark A. G.
Published: January 2020

Differing incidences of
Vibrio parahaemolyticus
reported by separate government agencies are attributable to sample handling and subsequent isolation techniques.
Effect of growth substrate on thermal death of thermophilic bacteria
Authors: Merkel G J , Perry J J
Published: January 2020

The heat sensitivity of gram-negative, hydrocarbon-utilizing thermophilic bacteria was altered by a change in growth substrate. Thermophilic strains CC-6, BI-1, and LEH-1, grown with acetate or n-heptadecane as the carbon source, had a higher survival rate when incubated 5 degrees C above their maximum growth temperature than cells of the same organism after growth on glucose or glycerol. There was a correlation between the growth substrated, heat resistance, and the ratios of cellular n-hexadecanoic acid/branched hexadecanoic acid and n-heptadecanoic acid/branched heptadecanoic acid. The bacterial cells that were more heat resistant had ratios of straight-chain/branched-chain fatty acids above 1.0, whereas the heat-sensitive cells had ratios below 0.6.
Isolation of the etiological agent of primary amoebic meningoencephalitis from artifically heated waters
Authors: Stevens A R , Tyndall R L , Coutant C C , Willaert E
Published: January 2020

To determine whether artificial heating of water by power plant discharges facilitates proliferation of the pathogenic free-living amoebae that cause primary amoebic meningoencephalitis, water samples (250 ml) were taken from discharges within 3,000 feet (ca. 914.4 m) of power plants and were processed for amoeba culture. Pathogenic Naegleria fowleri grew out of water samples from two of five lakes and rivers in Florida and from one of eight man-made lakes in Texas. Pathogenic N. fowleri did not grow from water samples taken from cooling towers and control lakes, the latter of which had no associated power plants. The identification of N. fowleri was confirmed by pathogenicity in mice and by indirect immunofluorescence analyses, by using a specific antiserum.
Metabolism of dibenzothiophene by a Beijerinckia species
Authors: Laborde A L , Gibson D T
Published: January 2020

Beijerinckia B8/36 when grown with succinate in the presence of dibenzothiophene, accumulated (+)-cis-1,2-dihydroxy-1,2-dihydrodibenzothiophene and dibenzothiophene-5-oxide in the culture medium. Each metabolite was isolated in crystalline form and characterized by a variety of chemical techniques, cis-Naphthalene dihydrodiol dehydrogenase, isolated from Pseudomonas putida, oxidized (+)-cis-1,2-dihydroxy-1,2-dihydrodibenzothiophene to a compound that was tentatively identified as 1,2-dihydroxydibenzothiophene. The same product was formed when crude cell extracts of the parent strain of Beijerinckia oxidized (+)-cis-1,2-dihydroxy-1,2-dihydrodibenzothiophene under anaerobic conditions. Further metabolism of 1,2-dihydroxydibenzothiophene by heat-treated cell extracts led to the formation of 4[2-(3-hydroxy)-thionaphthenyl]-2-oxo-3-butenoic acid. The latter compound was metabolized by crude cell extracts to 3-hydroxy-2-formylthionaphthene. Further degradation of this metabolite was not observed.
Patulin production by Byssochlamys spp. in fruit juices
Authors: Rice S L , Beuchat L R , Worthington R E
Published: January 2020

Ten strains of Byssochlamys fulva and three strains of B. nivea were cultured in a laboratory medium and tested for their ability to produce patulin. Two strains of B. fulva and all three strains of B. nivea produced the mycotoxin. One strain of B. fulva produced patulin in 11 of 13 processed fruit juices, with greatest amounts being produced in blueberry, red raspberry, and boysenberry juices, whereas no patulin was detected in prune or tomato juices. Grown in Concord grape juice at 18, 25, 30, and 38 degrees C, this strain produced the highest patulin concentration at 18 degrees C after 25 days, whereas biomass production was greatest at 25 and 30 degrees C after 20 and 25 days.
Microbial conversion of DL-2-amino-delta2-thiazoline-4-carboxylic acid to L-cysteine and L-cystine: screening of microorganisms and identification of products
Authors: Sano K , Yokozeki K , Tamura F , Yasuda N , Noda I , Mitsugi K
Published: January 2020

Microorganisms able to form L-cysteine from DL-2-amino-delta2-thiazoline-4-carboxylic acid (DL-ATC), a chemical intermediate in the synthesis of DL-cysteine, were isolated from soil samples and classified as Pseudomonas sp., Pseudomonas cohaerens, P. desmolytica, and P. ovalis. Thirteen L-cysteine-producing bacteria were also found in among 463 stock cultures representing 37 genera. These were Achromobacter delmarvae. Alcaligenes denitrificans, Bacillus brevis, Brevibacterium flavum, Enterobacter aerogenes, Erwinia carotovora, Escherichia coli, Micrococcus sodonensis, Myocoplana dimorpha, Sarcina lutea, Serratia marcescens, Flavobacterium acidoficum, and Pseudomonas ovalis. In the presence of intact cells of Pseudomonas sp. AJ 3854, 6.1 mg of L-cysteine and/or L-cystine per ml was produced from 10 mg of DL-ATC-3H2O per ml in a molar yield of 100%. This finding suggests that racemization and asymmetric hydrolysis occurred simultaneously in this incubation mixture. After the complete oxidation of cysteine to cystine by aeration in the presence of ferrous ion, crystalline cystine was isolated; its configuration was the L isomer based on data from X-ray diffraction, microbioassay, and optical rotation studies.
High concentrations of horse serum inhibit growth of corn stunt spiroplasma
Authors: Igwegbe E C
Published: January 2020

Corn stunt spiroplasma (CSS) grew faster and achieved higher titers in liquid or agar medium containing 5 or 10 percent horse serum than it did in medium containing 20 percent horse serum. When growth in liquid medium was initiated with a small inoculum, CSS achieved excellent growth in the presence of 5 percent serum but did not grow in medium containing 0 or 20 percent serum. Addition of arginine to liquid or agar medium supplemented with 20 percent serum stimulated CSS growth, but addition to that containing 5 percent serum did not.
Phototrophic purple and green bacteria in a sewage treatment plant
Authors: Siefert E , Irgens R L , Pfennig N
Published: January 2020

In all purification stages of a biological sewage treatment plant, phototrophic bacteria were detected by the method of viable cell counts. The predominant species identified belonged to the genus Rhodopseudomonas of purple nonsulfur bacteria. The number of phototrophic bacteria was highest in wastewater containing sludge. In activated sludge, an average of 10(5) viable cells/ml was found; the number depended upon concentration of sludge rather than on seasonal changes in light conditions in the course of a year. Bacteriochlorophyll a was extracted from activated sludge. Relative to the viable counts of phototrophic bacteria, the content of bacteriochlorophyll a was 5- to 10-fold higher than that of three representative pure cultures. By incubation of activated and digester sludge under different environmental conditions, it was shown that phototrophic bacteria can complete with other bacteria only under anaerobic conditions in the light.
Construction of a urocanic acid-producing strain of Serratia marcescens by transduction
Authors: Kisumi M , Nakanishi N , Takagi T , Chibata I
Published: January 2020

In Serratia marcescens, the mutation responsible for triazolealanine (TRA) resistance was transferred from a TRA-resistant mutant to a urocanase-less mutant by PS20-mediated transduction. The two crosses were performed using as donors two TRA-resistant mutants, whose phenotypes included increased levels of histidine-biosynthetic enzymes and feedback-insensitive phosphoribosyltransferase. In one cross, TRA-resistant transductants were urocanase-less mutants having only increased levels of the enzymes and barely detectable levels of urocanic acid. In the other cross, the transductants were urocanase-less mutants having both phenotypes of the donor, and most produced high concentrations (10.5 mg/ml) of urocanic acid.
Purification and some properties of riboflavin synthetase from Bacillus stearothermophilus ATCC 8005
Authors: Suzuki Y , Terai Y , Abe S
Published: January 2020

A riboflavin synthetase was purified 51-fold from a thermophilic organism, Bacillus stearothermophilus ATCC 8005, that grew at 40 to 72 degrees C. Some of the properties of the enzyme are: (i) its temperature optimum was 95 degrees C, and the activity was negligible below 40 degrees C; (ii) the Arrhenius plot of the initial reaction rates was concave upward, with a break at 65 degrees C, and the apparent activation energies below and above 65 degrees C were 4.2 X 10(4) and 6.7 X 10(4) J/mol, respectively; (iii) the enzyme was fairly stable up to 60 degrees C without 6,7-dimethyl-8-ribityllumazine; this substance protected the enzyme from inactivation above 60 to 97 degrees C; (iv) the pH range for stability was 6.0 to 10.0 at 26 degrees C and 6.3 to 7.6 at 55 degrees C; (v) the enzyme was highly resistant at 26 degrees C to denaturation in 8 M urea, but the tolerance was extremely low at 55 degrees C; (vi) its molecular weight was estimated at 45,000; (vii) the Km for 6,7-dimethyl-8-ribityllumazine was 23 micrometer at 55 degrees C and 29 micrometer at 75 degrees C; (viii) its pH optimum was 6.7 to 7.2; (ix) 6-methyl-7-hydroxy-8-ribityllumazine was a competitive inhibitor (Ki = 0.18 micrometer); (x) the activity was sensitive to heavy-metal ions and thiol reagents; (xi) the enzyme did not require cofactor or a carbon donor; and (xii) the molar ratio of 6,7-dimethyl-8-ribityllumazine consumption to riboflavin formation was 2 throughout the entire reaction. Properties i through vi distinguish this enzyme from riboflavin synthetases purified by other investigators from mesophilic organisms, Ashbya gossypii, Eremothecium ashbyii, Escherichia coli, yeast, and spinach.
Determination of fatty acid compositions of Bacillus cereus and related bacteria: a rapid gas chromatographic method using a glass capillary column
Authors: Niskanen A , Kiutamo T , R�is�nen S , Raevuori M
Published: January 2020

A rapid gas chromatographic method for the determination of fatty acid compositions of Bacillus cereus and related bacteria is presented. By the use of a free fatty acid phase-coated glass capillary column, the complete separation of fatty acids, including the branched ones, was achieved. The method enables a more distinct differentiation of Bacillus species than can be obtained with packed columns.
Tryptophan excretion by a bradytroph of Hansenula polymorpha growing in methanol
Authors: Sanchez S , Demain A L
Published: January 2020

The growth of a bradytrophic mutant isolated from the methanol-utilizing yeast Hansenula polymorpha was found to be stimulated by both tyrosine and phenylalanine. The mutant contained about half as much chorismate mutase activity as the wild-type strain. When grown in a medium containing 2% mehtanol as the major carbon and energy source, the bradytroph excreted a low but significant level (28 mg/liter) of L-tryptophan.
Bacterial and spontaneous dehalogenation of organic compounds
Authors: Omori T , Alexander M
Published: January 2020

Only 3 of more than 500 soil enrichments contained organisms able to use 1,9-dichlorononane as a sole carbon source. One isolate, a strain of Pseudomonas, grew on the compound and released much of the halogen as chloride. Resting cells dehalogenated 1,9-dichlorononane aerobically but not anaerobically. Pseudomonas sp. grew on and resting cells dehalogenated 1,6-dichlorohexane, 1,5-dichloroheptane, 2-bromoheptanoate, and 1-chloro-, 1-bromo-, and 1-iodoheptane, but the bacterium cometabolized but did not grow on 3-chloropropionate. p-Methylbenzyl alcohol, chloride, and p-methylbenzoate were formed when resting cells were incubated with alpha-chloro-p-xylene; the first two products were also formed in the absence of the bacteria. Similarly, o- and m-methylbenzyl alcohols were generated from the corresponding chlorinated xylenes in the presence or absence of Pseudomonas sp. The formation of m- and p-chlorobenzoic acid from m- and p-chlorobenzyl chloride proceeded only in the presence of the cells, but p-chlorobenzyl alcohol was generated from p-chlorobenzyl chloride even in the absence of the bacterium. These results are discussed in terms of possible mechanisms of dehalogenation.
Response of terrestrial microorganisms to a simulated Martian environment
Authors: Foster T L , Winans L , Casey R C , Kirschner L E
Published: January 2020

Soil samples from Cape Canaveral were subjected to a simulated Martian environment and assayed periodically over 45 days to determine the effect of various environmental parameters on bacterial populations. The simulated environment was based on the most recent available data, prior to the Viking spacecraft, describing Martian conditions and consisted of a pressure of 7 millibars, an atmosphere of 99.9% CO2 and 0.1% O2, a freeze-thaw cycle of -65 degrees C for 16 h and 24 degrees C for 8 h, and variable moisture and nutrients. Reduced pressure had a significant effect, reducing growth under these conditions. Slight variations in gaseous composition of the simulated atmosphere had negligible effect on growth. The freeze-thaw cycle did not inhibit growth but did result in a slower rate of decline after growth had occurred. Dry samples exhibited no change during the 45-day experiment, indicating that the simulated Martian environment was not toxic to bacterial populations. Psychotrophic organisms responded more favorably to this environment than mesophiles, although both types exhibited increases of approximately 3 logs in 7 to 14 days when moisture and nutrients were available.
Production of branched-chain volatile fatty acids by certain anaerobic bacteria
Authors: Allison M J
Published: January 2020

Net production of isobutyric acid, isovaleric acid, and 2-methylbutyric acid by cultures of Bacteroides ruminicola and Megasphaera elsdenii on media that contained Trypticase or casein hydrolysate continued (up to 5 days) after growth had ceased. Only trace quantities of these acids were produced in a medium that contained a mixture of amino acids that did not include the branched-chain amino acids. M. elsdenii produced increased quantities of the branched-chain fatty acids in a medium that contained Trypticase when glucose was reduced or eliminated from the culture medium. However, B. ruminicola produced increased quantities of branched-chain fatty acids and of phenylacetic acid from Trypticase when glucose was supplied at 3 mg/ml rather than at 1 mg/ml. Single strains of Streptococcus bovis, Selenomonas ruminantium, Bacteroides amylophilus, and Butyrivibrio fibrisolvens did not produce branched-chain fatty acids.
Suggested procedure allowing use of plastic petri dishes in bacteriocin typing
Authors: Bauernfeind A , Burrows J R
Published: January 2020

After bacteria are mechanically removed from solid media, the remaining viable cells can be killed by exposure to chloroform vapors. Until recently, the applicability of this procedure was restricted to glass petri dishes. Here a procedure is described in which plastic petri dishes are used and remain stable in the presence of chloroform vapors.
Virus accumulation by the rock oyster Crassostrea glomerata
Authors: Bedford A J , Williams G , Bellamy A R
Published: January 2020

The accumulation of virus by the New Zealand rock oyster Crassostrea glomerata has been studied in a static seawater system using radioactively labeled reovirus type III and Semliki Forest virus. The uptake of virus was found to be less rapid than for the bacterium Escherichia coli and to be unaffected by the presence of the marine alga Dunaliella primolecta in the seawater. Accumulation was dependent on virus concentration, with saturation achieved at 4 X 10(10) reovirus particles per oyster, implying that an oyster possesses a large but finite number of sites for virus adsorption. When the rates of uptake of two viruses of similar size but differing surface properties were compared, the rate of accumulation of the lipoprotein-enveloped Semliki Forest virus was found to be less than that for the protein-enclosed reovirus. This observation, together with the finding that the oyster shell has a strong affinity for virus, suggests that surface properties, rather than size, are the principal factors governing the accumulation of viruses by filter-feeding marine bivalves.
Influence of ammonium chloride on the nitrogenase activity of nodulated pea plants (Pisum sativum)
Authors: Houwaard F
Published: January 2020

A study was made on the short-term effect of ammonium ions on the nitrogenase activity of pea root nodules. Nodulated pea plants (Pisum sativum), having reached maximum acetylene-reducing activity, were supplied with NH4Cl (20 mM). Nitrogenase activity of intact plants, detached nodules, and isolated bacteroids was measured at differed time intervals. A significant drop (20 to 40%) in the acetylene-reducing activity of treated intact plants and their detached nodules was observed after 1 day. No drop in the nitrogenase activity of bacteroids (assayed aerobically, or anaerobically after treatment with ethylenediaminetetraacetic acid-toluene) occurred for 2 to 4 days after the addition of NH4+ to the plants, depending on cultural conditions. From these results it is concluded that the adverse effect of NH4+ on acetylene reduction by intact plants and detached nodules during the first 2 days is not due to a decrease in the amount of nitrogenase in the bacteroids. It is suggested that the effect has to be attributed to a reduced supply to the bacteroids of energy-delivery photosynthates.
Use of [14C]lysine to detect microbial contamination in liquid foods
Authors: Mafart P , Bourgeois C , Duteurtre B , Moll M
Published: January 2020

A radiometric method for microbiological control in food industries is suggested. This method, based on the labeling of cells by [14C]lysine, was tested by using nine species of yeast and two species of bacteria.
Method for Correcting Laboratory Model Deep-Well Disposal System Data for Hydrostatic Pressure Effects
Authors: Horvath E. , Elkan G. H.
Published: January 2020

A pressure chamber for determining the effect of increased hydrostatic pressure on growth and metabolic activities of groundwater bacteria is described. The chamber was used to show that moderate increases in pressure (to about 100 atmospheres) result in increased growth of mixed cultures of industrial-injection-well bacteria and in the more complete degradation of formate and nitrate by these bacteria, as compared with identical cultures at atmospheric pressure.
Gastrointestinal microecology of BALB/c nude mice
Authors: Brown J F , Balish E
Published: January 2020

The aerobic, facultative, and anaerobic microorganisms cultivable from the stomachs, ilea, ceca, and colons of BALB/c athymic (nu/nu) mice (normal and wasting), thymus-implanted normal nude mice, and their heterozygous (nu/+) littermates were investigated. Ninety-one species representing 23 genera of bacteria and yeasts were isolated from the 27 mice. The wasting nude mice showed significantly lower numbers of lactobacilli in their stomach microbiota than did mice from the other three groups. The littermate animals appeared unique among the four groups in having corynebacteria as a major constituent of their stomach and ileal flora. The normal nude mice appeared to have a more diverse anaerobic stomach flora than their heterozygous littermates. These minor differences are discussed with respect to possible immunological, physiological, and environmental factors as their cause. Because the gastrointestinal microfloras of the mice from the four groups were not radically divergent from each other, it was concluded that loss of T-cell function does not dramatically alter the makeup of the cultivable gastrointestinal microflora in these mice.
Extracellular endo-beta-1,4-glucanase in Cellvibrio vulgaris
Authors: Oberkotter L V , Rosenberg F A
Published: January 2020

Endo-beta-1,4-glucanase of the cellulolytic bacterium Cellvibrio vulgaris is an actively secreted, truly extracellular enzyme, as supported by growth and secretion studies using filter paper as the sole carbon source.
Progesterone biotransformation by plant cell suspension cultures
Authors: Yagen B , Gallili G E , Mateles R I
Published: January 2020

Progesterone was converted to 5alpha-pregnane-3alpha-ol-20-one, delta4-pregnene-20alpha-ol-3-one, delta4-pregnene-14alpha-ol-3,20-dione, delta4-pregnene-7beta,14alpha-diol-3,20-dione, and delta4-pregnene-6beta,11alpha-diol-3,20-dione by cell cultures of Lycopersicon esculentum. Cell cultures of Capsicum frutescens (green) metabolized progesterone to delta4-pregnene-20alpha-ol-3-one in very high yield, and Vinca rosea yielded delta4-pregnene-20beta-ol-3-one and delta4-pregnene-14alpha-ol-3,20-dione. A stereospecific reduction of the keto groups and a double bond and stereospecific introduction of hydroxyl groups at the 6, 11, and 14 positions have been observed. The mono- and dihydroxylated progesterones have not previously been reported as metabolic products of progesterone by plant cell systems and represent de novo hydroxylation of a nonglycosylated steroid.
Substrate Preferences in Rumen Bacteria: Evidence of Catabolite Regulatory Mechanisms
Authors: Russell James B. , Baldwin R. L.
Published: January 2020

Five species of rumen bacteria with overlapping substrate fermentative capabilities were tested for substrate preferences and evidence of catabolite regulatory mechanisms. All five bacteria showed evidence of some type of catabolite regulatory mechanism. In the six-substrate test system that was used, utilization of every substrate was inhibited by another substrate in at least one of the bacteria. Inhibited versus noninhibited substrate data suggest that the five bacteria have different strategies of substrate utilization and thus occupy separate niches in the rumen. The significance of these observations to understanding the rumen ecosystem is discussed.
Detection of bacterial nitrite production from nitrate by a nitrate-starch-iodide agar medium
Authors: Reisner G S
Published: January 2020

A medium consisting of nitrate agar (Difco), modified by the addition of 1% starch and 1% KI, was used to detect the production of nitrite by a number of different bacterial species.
Chicken egg yolk stabilizes the reverse transcriptase activity in type C particles produced by cultured MOPC-315 murine myeloma cells
Authors: Gazit A , Yaniv A , Eylan E
Published: January 2020

Type C particles released from cultured murine myeloma MOPC-315 cells were significantly protected when the purification steps were all conducted in the presence of 10% chicken egg yolk fluid. The yolk fluid also slowed down the inactivation of viral particles during incubation at 37 degrees C and enabled full recovery of viral particles through several cycles of freezing and thawing. The purification of viral particles in the presence of yolk fluid did not affect the capability of the viral DNA polymerase to reverse-transcribe the virion RNA in vitro, nor that of the viral RNA to act as a functional template.
Production and analysis of citrinin in corn
Authors: Jackson L K , Ciegler A
Published: January 2020

A convenient method for the production and analysis of citrinin in corn is described. Up to 2.964 g of citrinin can be produced by Penicillium citrinum per kg of corn by harvesting on day 21 or later. The analysis method has a lower detection limit of 0.25 ppm. Heating citrinin-contaminated corn destroys citrinin but may produce another toxin instead.
Heavy-Metal and Antibiotic Resistance in the Bacterial Flora of Sediments of New York Bight
Authors: Timoney J. F. , Port Jennifer , Giles Janis , Spanier J.
Published: January 2020

The New York Bight extends seaward some 80 to 100 miles (ca. 129 to 161 km) from the Long Island and New Jersey shorelines to the edge of the continental shelf. Over 14 × 10
6
m
3
of sewage sludge, dredge spoils, acid wastes, and cellar dirt are discharged into this area each year. Large populations of
Bacillus
sp. resistant to 20 μg of mercury per ml were observed in Bight sediments contaminated by these wastes. Resistant
Bacillus
populations were much greater in sediments containing high concentrations of Hg and other heavy metals than in sediments from areas further offshore where dumping has never been practiced and where heavy-metal concentrations were found to be low. Ampicillin resistance due mainly to β-lactamase production was significantly (
P
< 0.001) more frequent in
Bacillus
strains from sediments near the sewage sludge dump site than in similar
Bacillus
populations from control sediments.
Bacillus
strains with combined ampicillin and Hg resistances were almost six times as frequent at the sludge dump site as in control sediments. This observation suggests that genes for Hg resistance and β-lactamase production are simultaneously selected for in
Bacillus
and that heavy-metal contamination of an ecosystem can result in a selection pressure for antibiotic resistance in bacteria in that system. Also, Hg resistance was frequently linked with other heavy-metal resistances and, in a substantial proportion of
Bacillus
strains, involved reduction to volatile metallic Hg (Hg°).
Effects of No. 2 Fuel Oil, Nigerian Crude Oil, and Used Crankcase Oil on Attached Algal Communities: Acute and Chronic Toxicity of Water-Soluble Constituents
Authors: Bott Thomas L. , Rogenmuser Kurt
Published: January 2020

Water extracts of a no. 2 fuel oil, a Nigerian crude oil, and used crankcase oil were examined for their effects on algal communities in experiments lasting several weeks conducted under near-natural conditions. No. 2 fuel oil extracts depressed algal biomass (chlorophyll
a
) and resulted in blue-green algal (cyanobacterial) dominance and decreased diatom occurrence. Changes in concentrations of chlorophyll
c
, which was specific for diatoms in this work, and phycocyanin, which was specific for blue-green algae, confirmed the observations. Used crankcase oil extracts also depressed biomass, but Nigerian crude extracts did not, and both these extracts had less effect on community composition than did no. 2 fuel oil extracts. Photosynthetic
14
C incorporation was both stimulated and depressed by exposure to extracts with hydrocarbon concentrations 0.038 to 0.124 mg/liter. Short-term exposure to higher concentrations (1.17 to 15.30 mg of hydrocarbons per liter) of no. 2 fuel oil extracts depressed photosynthetic
14
C incorporation by
Vaucheria
-dominated communities in all tests but one. Toxicity was greater from extracts prepared in the light than from extracts prepared in the dark.
Use of platinum electrodes for the electrochemical detection of bacteria
Authors: Wilkins J R
Published: January 2020

Platinum electrodes with surface area ratios of four to one were used to detect and enumerate a variety of gram-positive and gram-negative organisms. Linear relationships were established between inoculum size and detection time. End points for platinum electrodes were similar to those obtained with a platinum-reference electrode combination. Shape of the overall response curves and length of detection times for gram-positive organisms were markedly different than those for the majority of gram-negative species. Platinum electrodes are better than the platinum-reference electrode combination because of cost, ease of handling, and clearer definition of the end point.
Serological studies of a host range mutant of a lactic streptococcal bacteriophage
Authors: Jarvis A W
Published: January 2020

A host range mutant was isolated from a bacteriophage that attacked Streptococcus cremoris 114. The mutant was able to adsorb and grow on S. cremoris 266, where the parent phage could not. The mutant phage was unable to adsorb to the original bacterial host, S. cremoris 114. The change in host range was accompanied by an alteration in the neutralization antigen as shown by a change in neutralization rate by an anti-phage serum. Serum-blocking experiments confirmed the difference in neutralization antigen between parent and mutant phages. The two phages nevertheless had similar complement fixation antigens, confirming that one was a mutant derived from the other. A distinction between complement fixation and neutralization antigens, similar to that found for the coliphages and staphylococcal phages, has therefore been demonstrated for two lactic streptococcal phages.
Elution of poliovirus adsorbed to membrane filters
Authors: Farrah S R , Bitton G
Published: January 2020

At a constant pH of 9, recovery of poliovirus adsorbed to membrane filters was dependent on the chemical nature of the material used for elution. Neutral and basic acids were relatively good eluents, whereas acidic amino acids and organic acids were poor eluents.
Decreased glycogen mobilization during ochratoxicosis in broiler chickens
Authors: Huff W E , Doerr J A , Hamilton P B
Published: January 2020

Graded doses of pure ochratoxin A (0, 0.5, 1.0, 2.0, 4.0, and 8.0 microgram of toxin per g of feed) were incorporated into a commercial diet which was fed to chickens from hatching to 3 weeks of age, at which time the experiments were terminated. Liver glycogen levels were elevated significantly (P less than 0.05) by 4.0 and 8.0 microgram/g but not lower doses. Glucagon stimulation of glycogen mobilization was inhibited at the same concentrations. Histopathological examination revealed cytoplasmic but not nuclear deposits of glycogen in cells at the periphery of liver lobes. These data demonstrated that ochratoxin inhibited glycogenolysis. Impaired ability to generate glucose from glycogen could account for the increased susceptibility to cold stress previously reported to occur in ochratoxicosis. Based on present and prior observations, it seems possible that ochratoxin induces a syndrome which mimics the glycogen storage disease of type X which is caused by a deficiency in the cyclic AMP-dependent enzyme of the glycogenolytic enzymatic cascade.
Patterns of cell division, DNA base compositions, and fine structures of some radiation-resistant vegetative bacteria found in food
Authors: Sanders S W , Maxcy R B
Published: January 2020

Representative highly radiation-resistant Moraxella-Acinetobacter (M-A), Pseudomonas radiora, Micrococcus radiodurans, and Micrococcus radiophilus exhibited a wide variety of division systems and cell wall characteristics. However, the most resistant M-A possessed unusually thick cell walls, indicating a possible role of the cell wall in radiation resistance in the M-A. Thick septation was present in most of the bacteria studied, but was absent in P. radiora, thus excluding this as a necessity for high resistance. Reliable determination of the number of division planes of the M-A for use as a taxonomic criterion was achieved by the direct observation of dividing cells. The highly resistant M-A were found to divide in multiple planes and had base compositions of 54.0 to 57.5%, unlike typical Moraxella and/or Acinetobacter species. The taxonomic position of most highly resistant bacteria remains unclear.
Influence of Substratum Characteristics on the Attachment of a Marine Pseudomonad to Solid Surfaces
Authors: Fletcher Madilyn , Loeb G. I.
Published: January 2020

The attachment of a marine
Pseudomonas
sp. to a variety of surfaces was investigated, and the number of bacteria which became attached was related to the surface charge and degree of hydrophobicity of the substratum. Large numbers of bacteria attached to hydrophobic plastics with little or no surface charge [Teflon, polyethylene, polystyrene, poly(ethylene terephthalate)]; moderate numbers attached to hydrophilic metals with a positive (platinum) or neutral (germanium) surface charge; and very few attached to hydrophilic, negatively charged substrata (glass, mica, oxidized plastics). The results suggest that both electrostatic and hydrophobic interactions are involved in bacterial attachment.
Histamine production by Klebsiella pneumoniae and an incident of scombroid fish poisoning
Authors: Taylor S L , Guthertz L S , Leatherwood M , Lieber E R
Published: January 2020

A histamine-producing strain of Klebsiella pneumoniae was isolated from a sample of tuna sashimi implicated in an outbreak of scombroid fish poisoning. None of the other nine gram-negative bacterial strains isolated from the tuna sashimi was capable of equivalent histamine production. Bacterial histamine production was monitored in a tuna fish infusion broth (TFIB), and the implicated K. pneumoniae was capable of producing 442 mg of histamine per 100 g of tuna in TFIB in 7 h under controlled incubation conditions. Only 12 of 50 other K. pneumoniae strains, representing 5 distinct biochemical types, which had been originally isolated from foods, were able to produce such levels of histamine in TFIB. No correlation was found between histamine production and other biochemical characteristics or antibiotic resistance. Of the 12 histamine-producing strains, 11 belonged to type 2, which is characterized as indole negative with positive reactions in the urea and Voges-Proskauer tests. However, only 50% of the type 2 strains examined produced high levels of histamine in TFIB. Additionally, the implicated K. pneumoniae strain and one other strain belonged to type 1, which is characterized by positive reactions in the indole, urea, and Voges-Proskauer tests.
Oxidation of methane in the absence of oxygen in lake water samples
Authors: Panganiban A T , Patt T E , Hart W , Hanson R S
Published: January 2020

Methane was oxidized to carbon dioxide in the absence of oxygen by water samples from Lake Mendota, Madison, Wis. The anaerobic oxidation of methane did not result in the assimilation of carbon from methane into material precipitable by cold 10% trichloracetic acid. Only samples taken at the suface of the sediment of Lake Mendota were capable of catalyzine the anaerobic oxidation of methane. The rate of methane oxidation in the presence of oxygen was highest in samples taken from near the thermocline. Of the radioactive methane oxidized, 30 to 60% was assimilated into material precipitable by cold 10% trichloroacetic acid during aerobic incubation of the samples. These data support the conclusion that two distinct groups of methane-oxidizing organisms occur in stratifield lakes. Enrichments with acetate and methane as the sole sources of carbon and energy and sulfate as the electron acceptor resulted in the growth of bacteria that oxidize methane. Sulfate, acetate, and methane were all required for growth of enrichments. Acetate was not oxidized to carbon dioxide but was assimilated by cells. Methane was not assimilated but was oxidized to carbon dioxide in the absence of air.
Production of mycophenolic acid by Penicillium roqueforti strains
Authors: Lafont P , Debeaupuis J P , Gaillardin M , Payen J
Published: January 2020

Sixteen strains of Penicillium roqueforti Thom, isolated from blue-molded cheeses, were studied. In vitro, all of these strains produced mycophenolic acid, some on the order of 0.8 to 4 mg/g od dry culture. The greatest yields were obtained after 10 days of incubation of cultures at 15 degrees C. However, under some experimental conditions, mycophenolic acid was not alone responsible for the toxicity of culture extracts to chicken embryos.
Induction of mutation in Escherichia coli by freeze-drying
Authors: Tanaka Y , Yoh M , Takeda Y , Miwatani T
Published: January 2020

The effect of freeze-drying on phenotypic reversion of amino acid auxotrophy to prototrophy was studied in Escherichia coli. In a radioresistant strain, E. coli H/r 30 (uvr+ exr+), which can repair the deoxyribonucleic acid damaged due to freeze-drying, an increased mutation frequency from auxotrophy to prototrophy was observed with increased time of freeze-drying of the cells. On the other hand, in a radiosensitive strain, E. coli NG 30 (recA), which cannot repair the damaged deoxyribonucleic acid due to a lack of repair enzyme system, no significant reversion occurred, although the survival rate was very low. The rate of phenotypic reversion dut to freeze-drying in both E. coli RIMD 0509109 (uvr+ exr+) and RIMD 0509115 (uvr exr+) was almost the same, indicating that the phenomenon is independent of the uvr character. From these results it is concluded that mutation was induced in E. coli cells during the rehydration when the damaged deoxyribonucleic acid was repaired by exr character of the cells. Thus, we propose that a serious consideration should be paid to the freeze-drying technique to preserve bacterial cells.
Utilization of chlorobenzoates by microbial populations in sewage
Authors: DiGeronimo M J , Nikaido M , Alexander M
Published: January 2020

Microorganisms in sewage decomposed 3.4-dichlorobenzoate and m-, p-, and o-chlorobenzoates. As the substrate disappeared, populations capable of growing on these compounds proliferated. Neither 2,4-dichlorobenzoate nor 2,3,6-trichlorobenzoate was destroyed by the sewage microflora. The addition of glucose or benzoate and m-chlorobenzoate to the sewage did not promote degradation of 2,4-di- or 2,3,6-trichlorobenzoates. The populations responsible for the biodegradation of the chlorinated compounds were initially less than 100 cells/ml. During the metabolism of m-chlorobenzoate, 5-chlorosalicylate and 4-chlorocatechol were formed.