bluuebunny/crossref_metadata_2025 huggingface dataset:
Smouldering epidemic of Yersinia pseudotuberculosis in barn rats
Authors: Kaneko K I , Hamada S , Kasai Y , Hashimoto N
Published: January 2020

Yersinia pseudotuberculosis was isolated from 8 (8 Rattus norvegicus) of 270 (259 R. norvegicus and 11 R. rattus) rats examined. Seasonal variation was not found in the incidence of isolations. The isolation occurred almost equally in both young and old rats. The isolated strains were determined as serovar IB in one rat, and serovar IVA in seven rats. The strains were isolated from the contents of the intestinal tract (the duodenum, jejunum, ileum, cecum, colon, and rectum), the spleen, liver and mesenteric lymph nodes; they were not detected in the kidneys. Agglutinin titer in the eight rats was no more than 32.
Production of antibody against T-2 toxin
Authors: Chu F S , Grossman S , Wei R D , Mirocha C J
Published: January 2020

Antibody against T-2 toxin was obtained after immunization of rabbits with bovine serum albumin-T-2 hemisuccinate conjugate. The antibody had greatest binding efficiency for T-2 toxin, less efficiency for HT-2, and least for T-2 triol. Cross-reaction of antibody with neosolaniol, T-2 tetraol, and 8-acetyl-neosolaniol was very weak. Diacetoxyscirpenol, trichodermin, vomitoxin, and verrucarin A essentially gave no cross-reaction with the antibody. The sensitivity of the binding assay for T-2 toxin detection was in the range of 1 to 20 ng per assay. Detailed methods for the preparation of the conjugate and the production of immune serum and methods for antibody determination are described.
Effect of two organophosphorus insecticides on the phosphate-dissolving soil bacteria
Authors: Congregado F , Simon-Pujol D , Ju�rez A
Published: January 2020

Dimethoate and malathion added to soil at 10 and 100 microgram/g caused an initial stimulation of CO2 production. Total counts of bacterial propagules were increased. All insecticide applications increased bacteria producing phospholipases from week 1 until week 4 after the application; bacteria then returned to the original levels.
Growth of a Bacterium Under a High-Pressure Oxy-Helium Atmosphere
Authors: Taylor Craig D.
Published: January 2020

Growth of a barotolerant marine organism, EP-4, in a glutamate medium equilibrated with an oxy-helium atmosphere at 500 atmospheres (atm; total pressure) (20°C) was compared with control cultures incubated at hydrostatic pressures of 1 and 500 atm. Relative to the 1-atm control culture, incubation of EP-4 at 500 atm in the absence of an atmosphere resulted in an approximately fivefold reduction in the growth rate and a significant but time variant reduction in the rate constants for the incorporation of substrate into cell material and respiration. Distinct from the pressurized control and separate from potential effects of dissolution of helium upon decompression of subsamples, exposure of the organism to high-pressure oxy-helium resulted in either a loss of viability of a large fraction of the cells or the arrest of growth for one-third of the experimental period. After these initial effects, however, the culture grew exponentially at a rate which was three times greater than the 500-atm control culture. The rate constant for the incorporation of substrate into cell material was also enhanced twofold in the presence of high-pressure oxy-helium. Dissolved oxygen was well controlled in all of the cultures, minimizing any potential toxic effects of this gas.
High-resolution gas chromatographic profiles of volatile organic compounds produced by microorganisms at refrigerated temperatures
Authors: Lee M L , Smith D L , Freeman L R
Published: January 2020

Three different strains of bacteria isolated from spoiled, uncooked chicken were grown in pure culture on Trypticase soy agar supplemented with yeast extract. The volatile organic compounds produced by each culture were concentrated on a porous polymer precolumn and analyzed by high-resolution gas chromatographic mass spectrometry. Twenty different compounds were identified. Both qualitative and quantitative differences in the chromatographic profiles from each culture were found.
Ecology, serology, and enterotoxin production of Vibrio cholerae in Chesapeake Bay
Authors: Kaper J , Lockman H , Colwell R R , Joseph S W
Published: January 2020

A total of 65 isolates of Vibrio cholerae, serotypes other than O--1, have been recovered from water, sediment, and shellfish samples from the Chesapeake Bay. Isolations were not random, but followed a distinct pattern in which salinity appeared to be a controlling factor in V. cholerae distribution. Water salinity at stations yielding V. cholerae (13 out of 21 stations) was 4 to 17 0/00, whereas the salinity of water at stations from which V. cholerae organisms were not isolated was less than 4 or greater than 17 0/00. From results of statistical analyses, no correlation between incidence of fecal coliforms and V. cholerae could be detected, whereas incidence of Salmonella species, measured concurrently, was clearly correlated with fecal coliforms, with Salmonella isolated only in areas of high fecal coliform levels. A seasonal cycle could not be determined since strains of V. cholerae were detectable at low levels (ca. 1 to 10 cells/liter) throughout the year. Although none of the Chesapeake Bay isolates was agglutinable in V. cholerae O group 1 antiserum, the majority for Y-1 adrenal cells. Furthermore, rabbit ileal loop and mouse lethality tests were also positive for the Chesapeake Bay isolates, with average fluid accumulation in positive ileal loops ranging from 0.21 to 2.11 ml/cm. Serotypes of the strains of V. cholerae recovered from Chesapeake Bay were those of wide geographic distribution. It is concluded from the data assembled to date, that V. cholerae is an autochthonous estuarine bacterial species resident in Chesapeake Bay.
Conversion of 2,4,6-trinitrophenol to a mutagen by Pseudomonas aeruginosa
Authors: Wyman J F , Guard H E , Won W D , Quay J H
Published: January 2020

A strain of Pseudomonas aeruginosa reduced 2,4,6-trinitrophenol (picric acid) to 2-amino-4,6-dinitrophenol (picramic acid) under anaerobic conditions. Mutagenic assays of picric acid and picramic acid were carried out with histidine-requiring strains of Salmonella typhimurium. Picric acid (10 micrograms per plate) demonstrated mutagenicity (both frame shift and base substitution-gype mutations) only after activation with a rat liver homogenate preparation. Picramic acid (1 microgram per plate) induced both base pair substitution and frame shift-tupe mutations without activation by the rat liver preparation.
Optimizing the Continuous Production of
Candida utilis
and
Saccharomycopsis fibuliger
on Potato Processing Wastewater
Authors: Lemmel S. A. , Heimsch R. C. , Edwards L. L.
Published: January 2020

The yeasts
Candida utilis
and
Saccharomycopsis fibuliger
were propagated as a source of single-cell protein in a continuous, mixed, aerobic, single-stage cultivation on blancher water generated during potato processing. A series of steady-state experiments based on a two-level factorial design, half-replicate modified with an intermediate experiment, was performed to determine the effect of pH, 3.8 to 4.8; dissolved oxygen, 42 to 80% saturation; dilution rate, 0.17 to 0.31 h
−1
; and temperature, 27 to 32°C on the amount of carbon consumed, the rate of carbon consumption (

R
c

), the amount of reducing sugar consumed, the rate of sugar consumption (

R
g

), the amount of protein produced, the rate of protein production (

R
p

), the yield from carbon, and the yield from reducing sugar. The results were analyzed by stepwise multiple regression and Fisher's least significant difference test. Analyses showed that high dilution rates resulted in increased

R
c

,

R
g

, and

R
p

and indicated that a rate of 0.31 h
−1
was below the critical dilution rate. A temperature of 32°C increased the amount of carbon consumed by 34%. A pH of 4.3 to 4.8 increased the amount of protein produced. The yield from carbon was constant, and the relatively high yield from reducing sugar indicated that other substrates were consumed. Dissolved oxygen was in excess at 42% saturation and above. Since
C. utilis
predominated the mixed cultures and amylase production appeared to be limited, a single-stage fermentation lacked efficiency. The experimental design allowed preliminary optimization of major environmental variables with relatively few experiments and provided a basis for future kinetic studies.
Anaerobic metabolism of immediate methane precursors in Lake Mendota
Authors: Winfrey M R , Zeikus J G
Published: January 2020

Lake Mendota sediments and the immediate overlying water column were studied to better understand the metabolism of the methanogenic precursors H2/CO2 and acetate in nature. The pool size of acetate (3.5 microns M) was very small, and the acetate turnover time (0.22h) was very rapid. The dissolved inorganic carbon pool was shown to be large (6.4 to 8.3 mM), and the turnover time was slow (111 H.). CO2 was shown to account for 41 +/- 5.5% of the methane produced in sediment. Acetate and H2/CO2 were simultaneously converted to CH4. The addition of H2 to sediments resulted in an increase specific activity of CH4 from H(14)CO3- and a decrease in specific activity of CH4 from [2-14C]acetate. Acetate addition resulted in a decrease in specific activity of CH4 from H(14)CO3-. The metabolism of H(14)CO3- or [2-14C]acetate to 14CH4 was not inhibited by addition of acetate or H2. After greater than 99% of added [2-14C]acetate had been turned over, 42% of the label was recovered as 14CH4 20% was recovered as 14CO2 and 38% was incorporated into sediment. Inhibitor studies of [2-14C]acetate metabolism in sediments demonstrated that CHCl3 completely inhibited CH4 formation, but not CO2 production. Air and nitrate addition inhibited CH4 formation and stimulated CO2 production, whereas fluoroacetate addition totally inhibited acetate metabolism. The oxidation of [2-14C]acetate to 14CO2 was shown to decrease with time when sediment was incubated before the addition of label, suggesting depletion of low levels of an endogenous sediment electron acceptor. Acetate metabolism varied seasonally and was related to the concentration of sulfate in the lake and interstitial water. Methanogenesis occurred in the sediment and in the water immediately overlying the sediment during period of lake stratification and several centimeters below the sediment-water interface during lake turnovers. These data indicate that methanogenesis in Lake Mendota sediments was limited by "immediate" methane precursor availability (i.e., acetate and H2), by competition for these substrates by nonmethanogens, and by seasonal variations which altered sediment and water chemistry.
Injury and recovery of Escherichia coli after sublethal acidification
Authors: Przybylski K S , Witter L D
Published: January 2020

Over 99% of the viable cells of Escherichia coli K-12 were injured after a 60-min exposure to 0.3 M sodium acetate buffer at pH 4.2. Injured cells were those able to grow on Trypticase soy agar but unable to grow on violet red bile agar. The extent of both death and injury of acid-treated cells increased with decreasing pH or increasing concentration of acid. Injured cells were able to recover their colony-forming ability on violet red bile agar by incubation in Trypticase soy broth or potassium phosphate buffer before plating on the agar media. Direct neutralization of the injury medium did not allow recovery and, in fact, was lethal to the population. The addition of metabolic inhibitors to the Trypticase soy recovery broth was used to study the repair process. It was not affected by the presence of inhibitors of protein, cell wall, deoxyribonucleic acid, or ribonucleic acid syntheses. The addition of 2,4-dinitrophenol to the recovery medium also did not inhibit recovery. Actinomycin D and N,N'-dicyclohexylcarbodiimide were lethal to a proportion of the acidified cells but allowed another fraction of the population to recover. There were no detectable amounts of 260- or 280-nm-absorbing materials leaked during the course of acid injury.
Formation of N-nitrosamines from seconday animes and nitrite by resting cells of Escherichia coli B
Authors: Kunisaki N , Hayashi M
Published: January 2020

In the presence of resting cells of Escherichia coli B, the formation of N-nitrosamines from nitrite and secondary amines, such as dimethylamine and piperidine, was proportional to the incubation time and to the cell concentration. Optimum pH was 8.0. Boiled cells were incapable of nitrosating secondary amines. Although these experiments were carried out by using intact cells of E. coli B, the reaction followed Michaelis-Menten kinetics, and the apparent Km values calculated from Lineweaver-Burk plots were 0.12 +/- 0.03 M for dimethylamine and 0.07 +/- 0.02 M for nitrite. The apparent Km for piperidine was 0.15 +/- 0.05 M. The nitrosation was inhibited by high substrate concentrations. These results suggested that the formation of n-nitrosamines by resting cells of E. coli B apparently depends on their enzyme activities.
Unsuitability of polioviruses as indicators of virological quality of water
Authors: Katzenelson E , Kedmi S
Published: January 2020

Polioviruses could not be detected in about 50% of sewage samples despite routine administration of live attenuated poliovirus vaccine to the infant population.
Uneven distribution of aerobic mesophilic bacteria on human skin
Authors: Keith W A , Smiljanic R J , Akers W A , Keith L W
Published: January 2020

Viable aerobic mesophilic bacteria are not evenly distributed on the skin of the volar forearm. An increase in the size of the area sampled did not result in a proportional increase in the number of the viable aerobic mesophilic bacteria recovered.
Symbiotic Cellulose Degradation in Green Turtles,
Chelonia mydas
L
Authors: Fenchel T. M. , McRoy C. P. , Ogden J. C. , Parker P. , Rainey W. E.
Published: January 2020

A postgastric, fermentative breakdown of structural plant tissue was demonstrated for green turtles. About 90% cellulose was hydrolyzed. Bacterial and protozoan numbers compared with those of the rumen.
Iron and the antibotulinal efficacy of nitrite
Authors: Tompkin R B , Christiansen L N , Shaparis A B
Published: January 2020

Combination of nitrite, isoascorbate, and ethylenediaminetetraacetic acid were compared for their antibotulinal efficacy in perishable canned cured meat. A dose response relationship of available iron to the antibotulinal efficacy of nitrite was demonstrated.
Nitrogen Fixation Associated with the Rice Plant Grown in Water Culture
Authors: Watanabe Iwao , Cabrera Delfin R.
Published: January 2020

Acetylene reduction activity of intact rice plants was measured in closed assay chambers with plants grown in water culture. Acetylene was added to the liquid medium, and the ethylene formed was measured from both gas and liquid phases. After cutoff of mineral nitrogen supply and inoculation of fresh soil, rice plants grown from the seedling stage in water culture exhibited acetylene reduction activity after a lag period. However, rice plants grown in a paddy field and transferred to water culture were more suitable for N
2
fixation studies because of their higher, less variable acetylene reduction activity. The time course of acetylene reduction was monitored by continuous circulation of gas between the gas phase and the liquid phase, and the result showed an initial 2- or 3-h period of lower activity, followed by increased and almost constant activity up to 24 h. The effects on acetylene reduction activity of aeration, ammonium, chloramphenicol, and 3-(3,4-dichlorophenyl)-1,1-dimethylurea addition are reported. Ammonium was inhibitive at 0.33 mM, and its depressive effect was alleviated by ammonium uptake by the plants.
Urease-producing species of intestinal anaerobes and their activities
Authors: Suzuki K , Benno Y , Mitsuoka T , Takebe S , Kobashi K , Hase J
Published: January 2020

Urease activities of anaerobic bacteria that constituted predominant gut flora were examined. It was demonstrated that some strains of Eubacterium aerofaciens, E. lentum, and Peptostreptococcus products produced urease. They were the most numerous species in human feces. All strains of Bifidobacterium infantis and some strains of Bacteroides multiacidus, B. bifidum, Clostridium symbiosum, Fusobacterium necrophorum, F. varium, Lactobacillus fermentum, Peptococcus asaccharolyticus, and P. prevotii produced urease. The optimum pH of the Lactobacillus urease was found to be 4.0, whereas the pH value of B. multiacidus urease was 8.0.
Bactericidal effect of cysteine exposed to atmospheric oxygen
Authors: Carlsson J , Granberg G P , Nyberg G K , Edlund M B
Published: January 2020

Peptostreptococcus anaerobius VPI 4330-1 was exposed to atmospheric oxygen in a dilution bland (0.2% gelatin, salts, resazurin) solution. The organisms were rapidly killed when the solution contained cysteine. The organisms were effectively protected by catalase and horseradish peroxidase as well as by the metal ion-chelating agents 8-hydroxyquinoline and 2,2'-bipyridine. Superoxide dismutase increased the rate of killing of the organisms, whereas singlet oxygen quenchers and scavengers of hydroxyl free radicals did not protect the organisms from the toxic effect of cysteine. Hydrogen peroxide was formed when cysteine was exposed to oxygen in the dilution blank solution, and the reaction was inhibited by metal ion-chelating agents. The organisms were rapidly killed by 20 microM hydrogen peroxide in anaerobic dilution blank solution. The toxic effect of hydrogen peroxide in anaerobic dilution blank solution. The toxic effect of hydrogen peroxide was completely abolished by catalase and metal ion-chelating agents. These results indicated that hydrogen peroxide was formed in the dilution blank solution in a metal ion-catalyzed autoxidation of cysteine and that hydrogen peroxide was toxic to P. anaerobius VPI 4330-1 in a reaction also catalyzed by metal ions.
Emulsifier of Arthrobacter RAG-1: isolation and emulsifying properties
Authors: Rosenberg E , Zuckerberg A , Rubinovitz C , Gutnick D L
Published: January 2020

The oil-degrading Arthrobacter sp. RAG-1 produced an extracellular nondialyzable emulsifying agent when grown on hexadecane, ethanol, or acetate medium. The emulsifier was prepared by two procedures: (i) heptane extraction of the cell-free culture medium and (ii) precipitation with ammonium sulfate. A convenient assay was developed for measurement of emulsifier concentrations between 3 and 75 micrograms/ml. The rate of emulsion fromation was proportional to both hydrocarbon and emulsifier concentrations. Above pH 6, activity was dependent upon divalent cations; half-maximum activity was obtained in the presence of 1.5 mM Mg2+. With a ratio of gas oil to emulsifier of 50, stable emulsions were formed with average droplet sizes of less than 1 micron. Emulsifier production was parallel to growth on either hydrocarbon or nonhydrocarbon substrates during the exponential phase; however, production continued after growth ceased.
Metabolism of 3-chloro-, 4-chloro-, and 3,5-dichlorobenzoate by a pseudomonad
Authors: Hartmann J , Reineke W , Knackmuss H J
Published: January 2020

Pseudomonas sp. WR912 was isolated by continuous enrichment in three steps with 3-chloro-, 4-chloro-, and finally 3,5-dichlorobenzoate as sole source of carbon and energy. The doubling times of the pure culture with these growth substrates were 2.6, 3.3, and 5.2 h, respectively. Stoichiometric amounts of chloride were eliminated during growth. Oxygen uptake rates with chlorinated benzoates revealed low stereospecificity of the initial benzoate 1,2-dioxygenation. Dihydrodi-hydroxybenzoate dehydrogenase, catechol 1,2-dixoygenase, and muconate cycloisomerase activities were found in cell-free extracts. The ortho cleavage activity for catechols appeared to involve induction of isoenzymes with different stereospecificity towards chlorocatechols. A catabolic pathway for chlorocatechols was proposed on the basis of similarity to chlorophenoxyacetate catabolism, and cometabolism of 3,5-dimethylbenzoate by chlorobenzoate-induced cells yielded 2,5-dihydro-2,4-dimethyl-5-oxo-furan-2-acetic acid.
Nitrogen Fixation by Thermophilic Blue-Green Algae (Cyanobacteria): Temperature Characteristics and Potential Use in Biophotolysis
Authors: Miyamoto Kazuhisa , Hallenbeck Patrick C. , Benemann John R.
Published: January 2020

Thermophilic, nitrogen-fixing, blue-green algae (cyanobacteria) were investigated for use in biophotolysis. Three strains of
Mastigocladus laminosus
were tested and were found to be equally effective in biophotolysis as judged by nitrogenase activity. The alga,
M. laminosus
NZ-86-m, which was chosen for further study, grew well in the temperature range from 35 to 50°C, with optimum growth at 45°C, at which temperature acetylene reduction activity was also greatest. The maximum tolerable temperature was 55°C. Acetylene reduction activity was saturated at a light intensity of 1 × 10
4
ergs cm
−2
s
−1
. Atmospheric oxygen tension was found to be slightly inhibitory to acetylene reduction of both slowly growing and exponentially growing cultures. Nonsterile continuous cultures, which were conducted to test problems of culture maintenance, could be operated for 2 months without any significant decrease in nitrogenase activity or contamination by other algae. Nitrogen-starved cultures of
M. laminosus
NZ-86-m produced hydrogen at comparable rates to
Anabaena cylindrica.
The conversion efficiency of light to hydrogen energy at maximum rates of hydrogen production was 2.7%.
Clostridium botulinum growth and toxin production in tomato juice containing Aspergillus gracilis
Authors: Odlaug T E , Pflug I J
Published: January 2020

The ability of spores of one type A and one type B strain of Clostridium botulinum to grow and produce toxin in tomato juice was investigated. The type A strain grew at pH 4.9, but not at pH 4.8; the type B strain grew at pH 5.1, but not at pH 5.0. Aspergillus gracilis was inoculated along with C. botulinum spores into pH 4.2 tomato juice; in a nonhermetic unit, a pH gradient developed under the mycelial mat, resulting in C. botulinum growth and toxin production. In a hermetic unit, mold growth was reduced, and no pH gradient was detected; however, C. botulinum growth and low levels of toxin production (less than 10 50% lethal doses per ml) still occurred and were associated with the mycelial mat. The results of tests to find filterable or dialyzable growth factors were negative. It was demonstrated that for toxin production C. botulinum and the mold had to occupy the same environment.
Apparent Involvement of a Plasmid in Phaseotoxin Production by
Pseudomonas phaseolicola
Authors: Gantotti B. V. , Patil Suresh S. , Mandel Morton
Published: January 2020

Three naturally occurring toxigenic strains (HB-36, G-50, and HB-33), one nontoxigenic strain (HB-20), and one ultraviolet light-induced toxinless mutant (G-50 Tox
−
) of
Pseudomonas phaseolicola
were examined by dye-buoyant density equilibrium centrifugation for the presence of plasmid deoxyribonucleic acid. All strains contained plasmid deoxyribonucleic acid. Comparison of the plasmid deoxyribonucleic acid of different strains by agarose gel electrophoresis showed that strain G-50 harbored three plasmids, whereas the rest of the strains contained two plasmids each. Irrespective of their toxigenicity, all strains shared the large-sized first plasmid band, but differed with respect to other plasmids. Restriction endonuclease analyses of the plasmids indicated that a 22.50-megadalton plasmid was common to two of the toxigenic strains (HB-36 and G-50). However, strain HB-33, which is also toxigenic, contained a much smaller plasmid (4.23 megadaltons). It is hypothesized that this small plasmid may have arisen by a recombination event from a larger plasmid.
Vivo clearance of enteric bacteria from the hemolymph of the hard clam and the American oyster
Authors: Hartland B J , Timoney J F
Published: January 2020

American oysters, Crassostrea virginica, and hard clams, Mercenaria mercenaria, were experimentally contaminated with Escherichia coli, Salmonella typhimurium, and Shigella flexneri either by intracardial injection or via the natural route of ingestion. Bacterial inactivation in the hemolymph was monitored for 72 h after exposure to these enteric pathogens at 20 and 6 degrees C. At 6 degrees C, both mean bacterial uptake by ingestion and subsequent clearance was singificantly lower that at 20 degrees C. However, substantial bacterial clearance from the hemolymph occurred for both shellfish at each temperature. At 20 degrees C, viable bacteria were no longer detectable after 24 h in hemolymph of either clams or oysters after exposure to contaminated water containing 4 x 10(3) bacteria per ml.
Comparison of Maintenance Energy Expenditures and Growth Yields Among Several Rumen Bacteria Grown on Continuous Culture
Authors: Russell James B. , Baldwin R. L.
Published: January 2020

Maintenance energy expenditures were mesured for five rumen bacteria,
Selenomonas ruminantium, Butyrivibrio fibrisolvens, Bacteroides ruminicola, Megasphaera elsdenii
, and
Streptococcus bovis
, by using a complex medium with glucose as the carbon source. Large differences (as high as 8.5-fold) in maintenance energy expenditures were seen among these bacteria. The suggestion is made that maintenance requirements could be a significant determinant of bacterial competition in the rumen. Theoretical maximum growth yields, calculated from double reciprocal plots of yield versus dilution rate, were compared to theoretical
Y
ATP

max

values in order to estimate minimum molar adenosine 5′-triphosphate yields from glucose for each bacterium. Results showed that relative yield among the bacteria was growth rate dependent. At high dilution rates, both
S. ruminantium
and
S. bovis
produced lactate as their principal fermentation product. At lower dilution rates very little lactate was formed and growth yields increased. Acetate and ethanol were the predominant fermentation products of
S. bovis
at low dilution rates. Other workers have shown that
S. ruminantium
produces acetate and propionate at low growth rates.
Hydrogen Evolution from Alfalfa and Clover Nodules and Hydrogen Uptake by Free-Living
Rhizobium meliloti
Authors: Ruiz-Argüeso Tomás , Maier Robert J. , Evans Harold J.
Published: January 2020

A series of
Rhizobium meliloti
and
Rhizobium trifolii
strains were used as inocula for alfalfa and clover, respectively, grown under bacteriologically controlled conditions. Replicate samples of nodules formed by each strain were assayed for rates of H
2
evolution in air, rates of H
2
evolution under Ar and O
2
, and rates of C
2
H
2
reduction. Nodules formed by all strains of
R. meliloti
and
R. trifolii
on their respective hosts lost at least 17% of the electron flow through nitrogenase as evolved H
2
. The mean loss from alfalfa nodules formed by 19
R. meliloti
strains was 25%, and the mean loss from clover nodules formed by seven
R. trifolii
strains was 35%.
R. meliloti
and
R. trifolii
strains also were cultured under conditions that were previously established for derepression of hydrogenase synthesis. Only strains 102F65 and 102F51 of
R. meliloti
showed measurable activity under free-living conditions. Bacteroids from nodules formed by the two strains showing hydrogenase activity under free-living conditions also oxidized H
2
at low rates. The specific activity of hydrogenase in bacteroids formed by either strain 102F65 or strain 102F51 of
R. meliloti
was less than 0.1% of the specific activity of the hydrogenase system in bacteroids formed by H
2
uptake-positive
Rhizobium japonicum
USDA 110, which has been investigated previously.
R. meliloti
and
R. trifolii
strains tested possessed insufficient hydrogenase to recycle a substantial proportion of the H
2
evolved from the nitrogenase reaction in nodules of their hosts. Additional research is needed, therefore, to develop strains of
R. meliloti
and
R. trifolii
that possess an adequate H
2
-recycling system.
Colorimetric Enzyme-Linked Immunosorbent Assay for the Identification of Strains of
Rhizobium
in Culture and in the Nodules of Lentils
Authors: Berger J. A. , May S. N. , Berger L. R. , Bohlool B. B.
Published: January 2020

An indirect enzyme-linked immunosorbent assay has been developed to identify strains of
Rhizobium
in culture and in lentil nodules. The test can be used on cells from both fresh and frozen nodules obtained from plants grown either in a growth chamber or in the field. Test results were confirmed by immunofluorescence. The enzyme-linked immunosorbent assay technique can be used for field studies and requires less antisera than other serological techniques.
Degradation of polychlorinated biphenyls by mixed microbial cultures
Authors: Clark R R , Chian E S , Griffin R A
Published: January 2020

Three different enriched mixed cultures capable of degrading polychlorinated biphenylas were isolated from two soil samples and a river sediment, respectively. The predominant organisms found in all three mixed cultures were Alcaligenes odorans, Alcaligenes dentrificans, and an unidentified bacterium. The polychlorinated biphenyl isomers that were more water soluble and had lower chlorination were not only degraded at a faster rate than those that were less water soluble and had higher chlorination, but were also more completely utilized by these mixed cultures. This resulted in the presence in the environment of polychlorinated biphenyl residues consisting mainly of higher-chlorinated isomers. A form of cometabolism of polychlorinated biphenyls was also found with these cultures in the presence of acetate as the cosubstrate.
Measurement of the inactivation kinetics of poliovirus by ozone in a fast-flow mixer
Authors: Katzenelson E , Koerner G , Biedermann N , Peleg M , Shuval H I
Published: January 2020

Inactivation kinetics of poliovirus type 1 in ozone demand-free water was investigated by utilizing a fast-flow mixing apparatus. Ozonated water and a solution of ozone demand-free water containing a known quantity of poliovirus type 1 were introduced simultaneously into a mixing chamber, both at a constant rate. This mixture was then passed through a narrow tube of known length and diameter into a neutralizing solution. By altering the rate of introduction and/or tube length, different contact periods between ozone and virus could be determined with an accuracy of 0.01 s. Inactivation of the poliovirus occurred in two steps. During the first step, which lasted for 0.2 to 1.0 s, 95 to 99% of the virus was inactivated, depending on the ozone concentration (which ranged from 0.1 to 2.0 mg/liter). The second step apparently continued for several minutes; in this period the remainder of the virus was inactivated. An obvious dose-response relationship was demonstrated during the first step of the inactivation curve. The pH of the water slightly affected the viral inactivation rate, but these small differences seem to have no practical value.
Extracellular Proteases of
Mucor pusillus
Authors: Khan M. R. , Blain J. A. , Patterson J. D. E.
Published: January 2020

Mucor pusillus
was grown in different media for a period of 92 h, and the media were investigated for both milk-clotting and protease activities. It was observed that the ratio of extracellular milk-clotting activity to protease activity was the highest for 3% corn steep liquor containing 1% glucose as the source of carbon. Variation of both milk-clotting and protease activities was studied during the growth of the organism in the medium stated above. Separation of protease was carried out by ion-exchange chromatography at pH 8.0. Fractions collected were assayed for both activities simultaneously. The findings suggested that, instead of only one major acid protease, as reported by previous workers, two major acid proteases were produced. One of them had significant rennin-like activity, and the other lacked it. The former could be assumed to be the enzyme reported and studied by previous workers. The existence of two proteases was further confirmed by the appearance of two protease activity bands on polyacrylamide gels after electrophoresis. An attempt was made to separate the rennin-like enzyme from nonspecific protease activity by ammonium sulfate fractionation followed by ion-exchange chromatography at pH 6.0. The results indicated that the nonspecific protease activity due to the enzyme that lacked rennin action was substantially removed by the ammonium sulfate fractionation.
Lesions of swine lymph nodes as a diagnostic test to determine mycobacterial infection
Authors: Brown J , Neuman M A
Published: January 2020

Decisions as to the disposition of swine carcasses with lesions attributable to a mycobacterial infection are based upon a lesion criterion which is used as a diagnostic test by federal meat inspectors. Using this criterion, a federal meat inspector classified 58 of 100 pigs as "passed for cooking" and the other 42 pigs passed. Of the 58 pigs passed for cooking and the 42 pigs passed, mycobacterial isolations were made from the lymph nodes of 33 and 15 of the animals, respectively. The lesion criterion as a diagnostic test has the following attributes: 70% sensitive; 53% specific; 23% index of performance; 57% positive accuracy; and 67% negative accuracy.
Bacteria Associated with the Surface and Gut of Marine Copepods
Authors: Sochard M. R. , Wilson D. F. , Austin B. , Colwell R. R.
Published: January 2020

Little is known about the nature of bacteria associated with the surface and gut of marine copepods, either in laboratory-reared animals or in the natural environment. Nor is it known whether such animals possess a gut flora. The present report deals with studies of microorganisms isolated from healthy, laboratory-reared copepods of the species
Acartia tonsa
Dana, from several species of wild copepods collected from a marine or estuarine environment, and from laboratory dishes containing moribund copepods. Evidence for a unique gut flora in laboratory-reared animals is presented; the predominant bacteria were represented by the genus
Vibrio
. Other organisms such as
Pseudomonas
and
Cytophaga
were found less abundantly associated with the copepods and not specifically associated with the gut.
Polyacrylamide-Entrapped
Rhizobium
as an Inoculant for Legumes
Authors: Dommergues Y. R. , Diem Hoang G. , Divies C.
Published: January 2020

Pot experiments showed that
Rhizobium japonicum
cells entrapped in a polyacrylamide gel could be used as an inoculant for soybeans and compared favorably to laboratory-made peat base inoculant containing the same bacterial strain.

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Toxicity of parasporal crystals of Bacillus thuringiensis to the Indian meal moth, Plodia interpunctella
Authors: Schesser J H , Bulla L A
Published: January 2020

Toxicity of Bacillus thuringiensis parasporal crystals to the Indian meal moth, Plodia interpunctella, is described. The numbers of insects killed were in relation to crystal dry weight. Mortality was determined by comparing adult emergence in diets treated with crystals to emergence in untreated diets. There was only a 30% survival at an application of 0.414 microgram/cm2, and the mean 50% lethal concentration value was found to be 0.299 microgram/cm2. The use of emergence data has provided a reliable and reproducible bioassay for comparing relative toxicities of crystals, spores, and other cellular components to this economically important insect.
Glutaraldehyde Inactivation of Exotic Animal Viruses in Swine Heart Tissue
Authors: Cunliffe H. R. , Blackwell J. H. , Walker J. S.
Published: January 2020

Glutaraldehyde, 0.2%, in a 1:100 (wt/vol) ratio, inactivated four animal viruses (foot-and-mouth disease, swine vesicular disease, African swine fever, hog cholera) in swine heart tissues during 11-day exposures at 22 to 26°C.
Hydrogen Production by the Photosynthetic Bacterium
Rhodospirillum rubrum
Authors: Zürrer Hans , Bachofen Reinhard
Published: January 2020

Continuous photosynthetic production of hydrogen by
Rhodospirillum rubrum
in batch cultures was observed up to 80 days with the hydrogen donor, pure lactate or lactic acid-containing wastes, supplied periodically. Hydrogen was produced at an average rate of 6 ml/h per g (dry weight) of cells with whey as a hydrogen donor. In continuous cultures with glutamate as a growth-limiting nitrogen source and lactate as a hydrogen donor, hydrogen was evolved at a rate of 20 ml/h per g (dry weight). The composition of the gas evolved remained practically constant (70 to 75% H
2
, 25 to 30% CO
2
). Photosynthetic bacteria processing specific organic wastes could be an advantage in large-scale production of hydrogen together with food protein of high value, compared to other biological systems.
Comparison of EC broth and medium A-1 for the recovery of Escherichia coli from frozen shucked snow crab
Authors: Powell J C , Moore A R , Gow J A
Published: January 2020

Two variations of the multiple-tube fermentation technique were used to enumerate fecal coliforms in commercially processed, frozen crab meat. These were the EC confirmation test and a more rapid method that requires medium A-1. The method with medium A-1 was more specific than the EC confirmation test for detecting Escherichia coli type 1. E. coli was isolated from 84% of the positive medium A-1 tubes, whereas it was isolated from only 64% of the positive tubes of EC broth. When samples of crab meat were inoculated with known amounts of E. coli, better estimates of the known numbers were obtained by the medium A-1 method. Several species of nonfecal coliforms were isolated from cultures in EC broth. These belonged to the genera Klebsiella, Citrobacter, Enterobacter, and Serratia. Apparently these strains were naturally adapted to growth at an elevated temperature because the majority were able to grow at 44.5 degrees C when retested in EC broth. Fewer species of nonfecal coliforms were isolated from medium A-1. Those that were isolated belonged to the genera Citrobacter and Enterobacter.
Multiple antibiotic resistance in Rhizobium japonicum
Authors: Cole M A , Elkan G H
Published: January 2020

A total of 48 strains of the soil bacterium Rhizobium japonicum were screened for their response to several widely used antibiotics. Over 60% of the strains were resistant to chloramphenicol, polymyxin B, and erythromycin, and 47% or more of the strains were resistant to neomycin and penicillin G, when tested by disk assay procedures. The most common grouping of resistances in strains was simultaneous resistance to tetracycline, penicillin G, neomycin, chloramphenicol, and streptomycin (25% of all strains tested). The occurrence of multiple drug resistance in a soil bacterium that is not a vertebrate pathogen suggests that chemotherapeutic use of antibiotics is not required for the development of multiple drug resistance.
Evidence that bacteria can form new cells in airborne particles
Authors: Dimmick R L , Wolochow H , Chatigny M A
Published: January 2020

Serratia marcescens incubated for 8 h at 31 degrees C in a chemically defined medium contained in shake flasks was aerosolized into rotating-drum aerosol chambers at 30 degrees C and saturated humidity. Cells furnished tryptone (Difco) and glycerol just before aerosolization increased (in viable numbers and countable cells) almost twofold within 1 to 2 h after becoming airborne, whereas cells not furnished additional tryptone decreased in viable numbers at a faster rate than the number of particles removed by gravitational settling. Limited tests with a Coulter Counter showed that cell volume changes occurred in growing cells that did not occur in the nongrowing population.
Microbial metabolism of carbon monoxide in culture and in soil
Authors: Bartholomew G W , Alexander M
Published: January 2020

Nocardia salmonicolor readily oxidized CO to CO2. Slight activity was found among species of Actinoplanes, Agromyces, Microbispora, Mycobacterium, and other nocardias, and no oxidation was detected in the algae, fungi, and other bacteria tested. Carbon monoxide was oxidized rapidly to CO2 in the dark in two soils incubated in air or under flooded conditions, but little of the 14C from 14CO was incorporated into the organic fraction of these soils. The reaction was microbial because appreciable CO was not converted to CO2 in autoclaved or gamma-irradiated soil. Heating the soil for 25 min at 70 degrees C destroyed its CO-oxidizing activity. The incorporation of 14CO2 into the cells of microorganisms in soil and soil suspension was not enhanced by incubating the samples in the presence of CO, suggesting that CO oxidation was not the result of autotrophic metabolism. The oxidation of 17 mu 1 of CO per liter in the head space was nearly complete in 6 h in soil incubated in air or anaerobically.
Nitrogen Requirement of Iron-Oxidizing Thiobacilli for Acidic Ferric Sulfate Regeneration
Authors: Tuovinen Olli H. , Panda Fern A. , Tsuchiya Henry M.
Published: January 2020

Ammonium was shown to be a limiting nutrient for iron oxidation in cultures of
Thiobacillus ferrooxidans.
In addition, one strain was also able to assimilate nitrate, but not nitrite, for growth and coupled iron oxidation. Some amino acids (0.5 mM) were tested as a source of nitrogen; none clearly stimulated bacterial activity and inhibition was commonly encountered. Complex nitrogenous compounds were inhibitory at high concentrations (0.1 to 0.5%, wt/vol) and, at low concentrations, some clearly stimulated the bacterial iron oxidation in ammonium-limited cultures. Enhancement of iron oxidation by these compounds was also observed in ammonium-unlimited cultures, suggesting their possible role in providing trace nutrients and possibly carbon for the bacteria.
Dichloran-rose bengal medium for enumeration and isolation of molds from foods
Authors: King A D , Hocking A D , Pitt J I
Published: January 2020

Overgrowth by spreading molds such as Rhizopus and Mucor species is a problem with fungal enumeration media used for foods. Thirty-one antifungal compounds were surveyed for their ability to selectively inhibit such fungi while allowing growth of mycotoxigenic molds and other species of significance in food spoilage. Dichloran (2,6 dichloro-4-nitroaniline) restricted growth of Rhizopus stolonifer while allowing satisfactory growth of the other test molds. Three Rhizopus and Mucor species were encountered that were not inhibited by dichloran; these were controlled by the addition of rose bengal. The optimal medium, designated DRBC, contained 2 micrograms of dichloran and 25 micrograms of rose bengal per ml. DRBC, in pure culture tests and with food samples, restricted the colony size of spreading molds and recovered a wider range of species in higher numbers than other enumeration media.
Pasteurization of salted whole egg inoculated with Arizona or Salmonella
Authors: Ng H , Garibaldi J A , Ijichi K , Mihara K L
Published: January 2020

Recently, Arizona bacteria, close relatives of Salmonella, were recovered from salted whole egg that had been pasteurized by the presently recommended process of 63.3 degrees C (146 degrees F) for 3.5 min. Because of this and the fact that the heat resistance of Arizona in salted whole egg had not been determined, the present study was undertaken. Arizona or Salmonella, grown in Trypticase soy broth supplemented with 2% yeast extract in Fernbach flasks covered with aluminum foil over cotton and guaze at 35 degrees C with shaking at 176 rpm for about 96 h, were found to have the greatest degree of heat resistance. As expected, these cells, when inoculated into salted whole egg at 10(7) cells per ml, survived heating at 63.3 degrees C (146 degrees F) for 3.5 min in a two-phase slug flow heat exchanger. To consistently achieve a 7-log kill of typical Salmonella or Arizona, a treatment of 67 degrees C (152.6 degrees F) for 3.5 min was required. However, if a 7-log kill is mandatory, it remains to be determined whether this process affect the functional properties of this product.
Growth of
Candida ingens
on Supernatant from Anaerobically Fermented Pig Waste: Effects of Temperature and pH
Authors: Henry D. P. , Thomson Ruth H.
Published: January 2020

Candida ingens
, a pellicle-forming yeast utilizing volatile fatty acids, grew over a pH range of 4.1 to 6.0 on nonsterile supernatants from anaerobically fermented pig wastes; growth was inconsistent between pH 4.1 and 4.6. When ambient temperature above the pellicle was 21°C and the temperature of the medium was 29 to 32°C, a pH range of 4.8 to 5.0 gave yields of 1.90 to 3.31 g of dry matter per liter, and 0.059 to 0.065 mol of volatile fatty acids was utilized per liter. There was no advantage in utilization of volatile fatty acids and yield of dry matter in keeping the pH constant during a 24-h growth period.
C. ingens
grew at pH 4.8 and 5.0 when both ambient and medium temperatures were 30°C. When ambient temperature was 10°C, maximum yield and utilization of volatile fatty acids occurred at a medium temperature of 28 to 30°C.
Heat inactivation of catalase from Staphylococcus aureus MF-31
Authors: Andrews G P , Martin S E
Published: January 2020

The effects of heat on catalase from Staphylococcus aureus lysates were examined. Catalase activity increased with increasing concentrations of potassium phosphate buffer, when heated at temperatures between 50 and 65 degrees C for 10 min. Inactivation of catalase by NaCl during heating was demonstrated. Extended heating of S. aureus cells at 52 degrees C resulted in a slight decrease in catalase activity of the resultant lysates. This decrease was more pronounced in the presence of salt. Heating at 62 degrees C caused a decrease in catalase activity, but not complete inactivation. These results implicate the combined effects of heat, and NaCl in the inactivation of catalase from S. aureus. The findings are consistent with the hypothesis that H2O2 may accumulate as a result of decreased catalase activity and be responsible for the decreased colony-forming ability of stressed S. aureus.
Raffinose increases sporulation and enterotoxin production by Clostridium perfringens type A
Authors: Labbe R G , Rey D K
Published: January 2020

Replacement of starch with raffinose in Duncan and Strong sporulation medium improved percent sporulation in six of eight strains tested. Enterotoxin concentration in cell extracts was increased in the case of four of five known enterotoxin-positive strains. With strain NCTC 10240, levels of 0.3, 0.4, and 0.5% raffinose produced the highest enterotoxin concentration 300 to 320 micrograms of enterotoxin per mg of cell extract protein. At a level of 0.4% raffinose the highest enterotoxin concentration in cell extracts of NCTC 10240 occurred after 8 h of growth in Duncan and Strong medium. Enterotoxin produced in the presence of starch or raffinose by three separate strains all migrated at similar Rm by polyacrylamide gel electrophoresis.
Colonization of a portion of the bovine tongue by unusual filamentous bacteria
Authors: McCowan R P , Cheng K J , Costerton J W
Published: January 2020

Tongue samples from cattle on varied diets and ranging in age from 2 months to adult were studied by transmission and scanning electron microscopy to observe the in situ distribution and adhesion patterns of two readily identifiable genera of filamentous bacterial. The two, both members of the Simonsiellaceae, adhere to the epithelium by means of fibers which are produced on one side of the bacterial filaments and subsequently display a sidedness in their manner of adhesion to epithelial surfaces. Other bacterial populations found on the tongue were normally members of chains and seldom present as single cells. This suggests that filamentous or chain-forming bacteria may have a selective advantage over single bacteria in their ability to colonize and remain attached to the epithelium of the tongue.
Oxaloacetate Synthesis in
Butyrivibrio fibrisolvens
Authors: van Gylswyk N. O.
Published: January 2020

Phosphoenolpyruvate carboxykinase (adenosine 5′-triphosphate) was the only enzyme capable of carboxylating pyruvate or phosphoenolpyruvate that could be demonstrated in sonicated cells or cell-free extracts of a group 1 butyrivibrio.