bluuebunny/crossref_metadata_2025 huggingface dataset:
Inefficient accumulation of low levels of monodispersed and feces-associated poliovirus in oysters
Authors: Landry E F , Vaughn J M , Vicale T J , Mann R
Published: January 2020

The accumulation of low levels (0.002 to 0.18 PFU/ml) of both feces-associated and monodispersed poliovirus by oysters (Crassostrea virginica or C. gigas) and clams (Mercenaria mercenaria) was investigated. These levels were chosen to duplicate the conditions present in light to moderately polluted waters. Experiments were performed in both small- and large-scale flowing seawater systems, developed to mimic the natural marine habitats of shellfish. Under these experimental conditions, viral accumulation by physiologically active shellfish was only noted when water column concentrations exceeded approximately 0.01 PFU/ml. Bioaccumulation increased with increasing concentrations of both monodispersed and feces-associated viruses. At virus concentrations below this level, viruses were seldom detected in either clams or oysters. Evidence indicated that the lack of accumulation was not the result of inefficient extraction or detection methods. The modified Cat-Floc-beef extract procedure used in the experiment was found to be capable of detecting as few as 1.5 to 2.0 PFU per shellfish. Evidence is presented to indicate that an uptake-depuration equilibrium was present at virus exposure levels of 0.10 PFU/ml, but not at 0.01 PFU/ml. The results suggested that viral accumulation by shellfish may not be efficient at water column concentrations below congruent to 0.01 PFU/ml.
R-plasmid transfer in a wastewater treatment plant
Authors: Mach P A , Grimes D J
Published: January 2020

Enteric bacteria have been examined for their ability to transfer antibiotic resistance in a wastewater treatment plant. Resistant Salmonella enteritidis, Proteus mirabilis, and Escherichia coli were isolated from clinical specimens and primary sewage effluent. Resistance to ampicillin, chloramphenicol, streptomycin, sulfadiazine, and tetracycline was demonstrated by spread plate and tube dilution techniques. Plasmid mediation of resistance was shown by ethidium bromide curing, agarose gel electrophoresis, and direct cell transfer. Each donor was mated with susceptible E. coli and Shigella sonnei. Mating pairs (and recipient controls) were suspended in unchlorinated primary effluent that had been filtered and autoclaved. Suspensions were added to membrane diffusion chambers which were then placed in the primary and secondary setting tanks of the wastewater treatment plant. Resistant recombinants were detected by replica plating nutrient agar master plates onto xylose lysine desoxycholate agar plates that contained per milliliter of medium 10 micrograms of ampicillin, 30 micrograms of chloramphenicol, 10 micrograms of streptomycin, 100 micrograms of sulfadiazine, or 30 micrograms of tetracycline. Mean transfer frequencies for laboratory matings were 2.1 X 10(-3). In situ matings for primary and secondary settling resulted in frequencies of 4.9 X 10(-5) and 7.5 X 10(-5), respectively. These values suggest that a significant level of resistance transfer occurs in wastewater treatment plants in the absence of antibiotics as selective agents.
Cloning of a gene responsible for the biosynthesis of glutathione in Escherichia coli B
Authors: Murata K , Kimura A
Published: January 2020

A gene (gshI) responsible for gamma-glutamylcysteine synthetase (GSH-I) activity was cloned to construct an Escherichia coli B strain having high glutathione synthesizing activity. For this purpose, two E. coli B mutants (strains C912 and RC912) were used. C912 was deficient in GSH-I activity. RC912, a revertant of C912, had a GSH-I activity that was desensitized to feedback inhibition of reduced glutathione. To clone gshI, chromosomal DNAs of RC912 and plasmid vector pBR322 were digested with various restriction endonucleases and then ligated with T4 DNA ligase. The whole ligation mixture was used to transform C912, and the transformants were selected as tetramethylthiuramdisulfide-resistant colonies. Of about 20 resistant colonies, 2 or 3 became red when treated with nitroprusside and showed appreciably high GSH-I activities. The chimeric plasmid DNA, designated pBR322-gshI, was isolated from the strain having the highest GSH-I activity and transformed into RC912. The structure and molecular size of pBR322-gshI in RC912 were determined. The molecular size of this plasmid was 6.2 megadaltons, and the plasmid contained a 3.4-megadalton segment derived from RC912 chromosomal DNA, which included gshI gene. The GSH-I activity of RC912 cells containing pBR322-gshI was fourfold higher than that of RC912 cells without pBR322-gshI.
Selective isolation and enumeration of low numbers of Staphylococcus aureus by a procedure that relies on elevated-temperature culturing
Authors: Van Doorne H , Pauwels H P , Mossel D A
Published: January 2020

A procedure for the selective detection of Staphylococcus aureus was elaborated, consisting of three parts: (i) enrichment in liquid Baird-Parker medium; (ii) isolation on Baird-Parker agar incubated at 43 degrees C, and (iii) confirmation by means of the test for thermostable nuclease. Elevated-temperature incubation of Baird-Parker medium did not make it inhibitory to cells stressed by heat treatment or osmotic shock.
Isolation of Chromobacterium spp. from foods, soil, and water
Authors: Koburger J A , May S O
Published: January 2020

Chromobacterium violaceum, a soil and water inhabitant, has been implicated in human disease with a high mortality rate, particularly in the southeastern United States. The psychrotrophic Chromobacterium lividum has been isolated from foods, water, and soil, but is not considered pathogenic. To determine the distribution of Chromobacterium spp. in soil, water, and foods in the Gainesville area, we evaluated Bennett, Ryalls and Moss, and Aeromonas membrane agars for their ability to recover these organisms from various samples when incubated at 25 or 35 degrees C. Bennett agar was best for the isolation of both species when incubated at 25 degrees C; however, at 35 degrees C, Aeromonas membrane agar gave the highest recoveries of C. violaceum. C. violaceum was recovered only from soil and water, whereas C. lividum was frequently recovered from foods as well as soil and water.
Isolation and Characterization of
Vibrio vulnificus
from Two Florida Estuaries
Authors: Tamplin M. , Rodrick G. E. , Blake N. J. , Cuba T.
Published: January 2020

Vibrio vulnificus
was enumerated in seawater and shellfish from two Florida estuaries at selected seasonal intervals. There were significant fluctuations in the presence and numbers of
V. vulnificus.
Relatively high seawater temperature and salinity favored the presence of
V. vulnificus
in both seawater and shellfish samples.
Toxicity of aflatoxin B1 to penaeid shrimp
Authors: Wiseman M O , Price R L , Lightner D V , Williams R R
Published: January 2020

Single intramuscular injections of aflatoxin B1 into the tail muscle of Penaeus stylirostris produced 24- and 96-h median lethal doses of 100.5 (78.3 to 129.0) and 49.5 (29.8 to 82.3) mg/kg, respectively. A toxicity curve showed no threshold at the levels tested. The mortality response in a feeding study with P. vannamei was not dose dependent, but tissue and organ damage were similar to that seen in injected animals.
Action of Patulin on a Yeast
Authors: Sumbu Z. Lezi , Thonart P. , Bechet J.
Published: January 2020

The action of patulin on
Saccharomyces cerevisiae
was studied. At weak doses, the drug inhibited growth, but inhibition was transient. After 10 min, syntheses of rRNA, tRNA, and probably mRNA were blocked; this was shown by radioactive precursor incorporation assays and gel electrophoresis of RNAs. After recovery of growth, patulin disappeared from the medium. It seemed that this degradation resulted from the activity of an inducible enzymatic system. Induced cells resisted very high patulin concentrations.
Interaction between pectin and rat hindgut microflora
Authors: Mallett A K , Rowland I R , Wise A
Published: January 2020

The contents of the lower alimentary tract from rats fed a semisynthetic, pectin-supplemented diet showed increased nitrate reductase activity and an increase in the amount of luminal contents in the intestine and cecum. Nitrate reductase activity was associated with the insoluble fraction of the gut contents which was sedimented by centrifugation (5,100 X g,20 min) and was abolished after treating the animals with streptomycin, neomycin, and bacitracin for 7 days. The pectin-dependent increase in cecal size and microbial nitrate reduction were reversed when animals were transferred from a pectin-supplemented onto a control semisynthetic diet. Polygalacturonic acid (pectic acid) was without effect on either cecal size or cecal microbial nitrate reductase activity. The studies demonstrate that pectin influences microbial metabolism in the alimentary tract.
Relationship among fecal coliforms, Escherichia coli, and Salmonella spp. in shellfish
Authors: Hood M A , Ness G E , Blake N J
Published: January 2020

The relationship of fecal coliforms, Escherichia coli, and Salmonella spp. was examined in freshly harvested and stored shellfish. In 16 of 40 freshly collected oyster samples, fecal coliform levels were above the recommended wholesale level suggested by the National Shellfish Sanitation Program (less than or equal to 230/100 g), and Salmonella spp. were present in three of these samples. Salmonella spp. were not, however, present in any sample containing less than 230 fecal coliforms per 100 g. Analysis of the data suggests that low fecal coliform levels in both fresh and stored oysters are good indicators of the absence of Salmonella spp., but that high levels of fecal coliforms are somewhat limited in predicting the presence of Salmonella spp. E. coli levels correlated very strongly with fecal coliform levels in both fresh and stored oysters and clams, suggesting that there is no advantage in replacing fecal coliforms with E. coli as an indicator of shellfish quality.
Improved procedure for recovery of Yersinia enterocolitica from meats
Authors: Doyle M P , Hugdahl M B
Published: January 2020

A 1- to 3-day enrichment-KOH postenrichment procedure was evaluated and found to be as effective in recovering Yersinia enterocolitica from meats as a 14- to 21-day cold enrichment procedure, with or without KOH postenrichment. The shortened procedure consists of enriching 1.0- and 25-g samples of meat in phosphate-buffered saline (pH 7.2) at 25 degrees C. After incubation (48 and 72 h for 1.0-g samples and 24 and 48 h for 25-g samples); 0.5-ml portions of enrichment culture were treated with 4.5 ml of 0.25% KOH-0.5% NaCl for 2 min and 0.5% KOH-0.5% NaCl for 15 s, and 0.1-ml portions of treated culture were plated onto MacConkey or CIN agars or both. The procedure effectively recovered 2 to 12 cells of a number of both mouse-virulent and avirulent strains per g of ground beef with aerobic plate counts of approximately 10(6) to 10(7) CFU/g. Similarly, the procedure isolated both likely virulent and avirulent strains from porcine tongues (aerobic plate counts of 10(5) to 10(7) CFU/g) naturally contaminated with Y. enterocolitica. The organism was isolated from the tongues at similar rates by both shortened enrichment and cold enrichment procedures. Eight tongues were positive for serotype O:5,27 strains that agglutinate with WA-specific absorbed antiserum, an antiserum specific for mouse-virulent Y. enterocolitica (Doyle et al., Infect. Immun. 37:1234-1240, 1982), indicating that the oral cavity of swine is a reservoir of likely virulent serotype O:5,27 strains.
Growth Kinetics and Yield Coefficients of the Extreme Thermophile
Thermothrix thiopara
in Continuous Culture
Authors: Brannan Daniel K. , Caldwell Douglas E.
Published: January 2020

Thermothrix thiopara
did not appear to be stressed at high temperature (72°C). Both the actual and theoretical yields were higher than those of analogous mesophilic sulfur bacteria, and the specific growth rate (μ
max
) was more rapid than that of most autotrophs. The specific growth rate (0.58 h
−1
), specific maintenance rate (0.11 h
−1
), actual molar growth yield at μ
max
(
Y
max
= 16 g mol
−1
), and theoretical molar growth yield (

Y
G

= 24 g mol
−1
) were all higher for
T. thiopara
(72°C) than for mesophilic (25 to 30°C)
Thiobacillus
spp. The growth efficiencies for
T. thiopara
at 70 and 75°C (0.84 and 0.78) were significantly higher than at 65°C (0.47). Corresponding specific maintenance rates were highest at 65°C (0.41 h
−1
) and lowest at 70 and 75°C (0.11 and 0.15 h
−1
, respectively). Growth efficiencies of metabolically similar mesophiles were generally higher than for
T. thiopara.
However, the actual yields at μ
max
were higher for
T. thiopara
because its theoretical yield was higher. Thus, at 70°C,
T. thiopara
was capable of deriving more metabolically useful energy from thiosulfate than were mesophilic sulfur bacteria at 25 and 30°C. The low growth efficiency of
T. thiopara
reflected higher maintenance expenditures.
T. thiopara
had higher maintenance rates than
Thiobacillus ferroxidans
or
Thiobacillus denitrificans
, but also attained higher molar growth yields. It is concluded that sulfur metabolism may be more efficient overall at extremely high temperatures due to increased theoretical yields despite increased maintenance requirements.
Sulfate Reducers Can Outcompete Methanogens at Freshwater Sulfate Concentrations
Authors: Lovley Derek R. , Klug Michael J.
Published: January 2020

Acetate and hydrogen metabolism by sulfate reducers and methanogens in the profundal sediments of an oligotrophic lake were examined. Inhibition of sulfate reduction with molybdate stimulated methane production from both hydrogen and acetate. Molybdate did not stimulate methane production in sediments that were preincubated to deplete the sulfate pool. Sulfate reduction accounted for 30 to 81% of the total of terminal metabolism proceeding through sulfate reduction and methane production in Eckman grab samples of surface sediments. The ability of sulfate reducers to effectively compete with methanogens for acetate was related to the sulfate reducers' lower half-saturation constant for acetate metabolism at in situ sulfate concentrations. Processes other than sulfate reduction and methanogenesis consumed hydrogen at elevated hydrogen partial pressures and prevented a kinetic analysis of hydrogen uptake by sulfate reducers and methanogens. The demonstration that sulfate reducers can successfully compete with methanogens for hydrogen and acetate in sediments at in situ sulfate concentrations of 60 to 105 μM extends the known range of sediment habitats in which sulfate reduction can be a dominant terminal process.
Substrates for Sulfate Reduction and Methane Production in Intertidal Sediments
Authors: Winfrey Michael R. , Ward David M.
Published: January 2020

The activity of and potential substrates for methane-producing bacteria and sulfate-reducing bacteria were examined in marsh, estuary, and beach intertidal sediments. Slow rates of methane production were detected in all sediments, although rates of sulfate reduction were 100- to 1,000-fold higher. After sulfate was depleted in sediments, the rates of methane production sharply increased. The addition of methylamine stimulated methanogenesis in the presence of sulfate, and [
14
C]methylamine was rapidly converted to
14
CH
4
and
14
CO
2
in freshly collected marsh sediment. Acetate, hydrogen, or methionine additions did not stimulate methanogenesis. [
methyl
-
14
C]methionine and [2-
14
C]acetate were converted to
14
CO
2
and not to
14
CH
4
in fresh sediment. No reduction of
14
CO
2
to
14
CH
4
occurred in fresh sediment. Molybdate, an inhibitor of sulfate reduction, inhibited [2-
14
C]acetate metabolism by 98.5%. Fluoracetate, an inhibitor of acetate metabolism, inhibited sulfate reduction by 61%. These results suggest that acetate is a major electron donor for sulfate reduction in marine sediments. In the presence of high concentrations of sulfate, methane may be derived from novel substrates such as methylamine.
Dual-Substrate Plate Diffusion Assay for Proteases
Authors: Montville Thomas J.
Published: January 2020

A plate diffusion assay for endopeptidases was developed. Proteases applied to plates containing 1% casein, 1% gelatin, and 1.5% agar caused distinct zones reminiscent of immunoprecipitation bands. The diameter of the zones was linearly proportional to the log of the enzyme activity applied over a range from 0.01 to greater than 100 IU/ml.
Effect of chlorine treatment on infectivity of hepatitis A virus
Authors: Peterson D A , Hurley T R , Hoff J C , Wolfe L G
Published: January 2020

This study examined the effect of chlorine treatment on the infectivity of hepatitis A virus (HAV). Prodromal chimpanzee feces, shown to induce hepatitis in marmosets (Saguinus sp.), was clarified, and the virus was precipitated with 7% polyethylene glycol 6000, harvested, and resuspended. The suspension was layered onto 5 to 30% linear sucrose gradients and centrifuged; the fractions containing HAV were dialyzed, and a 1:500,000 dilution of this preparation induced hepatitis and seroconversion in 2 of 4 marmosets. A 1:50 dilution of this preparation served as inoculum. Untreated inoculum induced overt hepatitis and seroconversion in 100% (5 of 5) of marmosets inoculated intramuscularly. Inoculum treated for various periods (15, 30, or 60 min) with 0.5, 1.0, or 1.5 mg of free residual chlorine per liter induced hepatitis in 14% (2 of 14), 8% (1 of 12), and 10% (1 of 10) of marmosets, respectively, and induced seroconversion in 29, 33, and 10% of the animals. Inoculum treated with 2.0 or 2.5 mg of free residual chlorine per liter was not infectious in marmosets as determined by absence of hepatitis and seroconversion in the 13 animals tested. Thus, treatment levels of 0.5 to 1.5 mg of free residual chlorine per liter inactivated most but not all HAV in the preparation, whereas concentrations of 2.0 and 2.5 mg of free residual chlorine per liter destroyed the infectivity completely. These results suggest that HAV is somewhat more resistant to chlorine than are other enteroviruses.
Accumulation of sediment-associated viruses in shellfish
Authors: Landry E F , Vaughn J M , Vicale T J , Mann R
Published: January 2020

The present study focused on the importance of contaminated sediments in shellfish accumulation of human viruses. Epifaunal (Crassostrea virginica) and infaunal (Mercenaria mercenaria) shellfish, placed on or in cores, were exposed to either resuspended or undisturbed sediments containing bound poliovirus type 1 (LSc 2ab). Consistent bioaccumulation by oysters (four of five trials) was only noted when sediment-bound viruses occurred in the water column. Virus accumulation was observed in a single instance where sediments remained in an undisturbed state. While the incidence of bioaccumulation was higher with resuspended rather than undisturbed contaminated sediment, the actual concentration of accumulated viruses was not significantly different. The accumulation of viruses from oysters residing on uninoculated sediments. When clams were exposed to undisturbed, virus-contaminated sediments, two of five shellfish pools yielded viral isolates. Bioaccumulation of undisturbed sediments by these bivalves was considered marginal when related to the concentration of virus in contaminated sediments; they would only represent a significant threat when suspended in the water column. Arguments were advanced for water-column sampling in the region of the water-sediment interface to provide an accurate determination of the virological quality of shellfish harvesting waters.
Halophilic Nuclease of a Moderately Halophilic
Bacillus
sp.: Production, Purification, and Characterization
Authors: Onishi Hiroshi , Mori Tatsuro , Takeuchi Setsuo , Tani Keiko , Kobayashi Takekazu , Kamekura Masahiro
Published: January 2020

A moderately halophilic bacterium,
Bacillus
sp., isolated from rotting wood on the seashore in Nauru, produced an extracellular nuclease when cultivated aerobically in media containing 1 to 2 M NaCl. The enzyme was purified from the culture filtrate to an electrophoretically homogeneous state by ethanol precipitation, DEAE-Sephadex A-50 column chromatography, and Sephadex G-200 gel filtration. The enzyme consisted of two charge isomers and showed both RNase and DNase activities. Molecular weight was estimated to be 138,000 by Sephadex G-200 gel filtration. The enzyme had marked halophilic properties, showing maximal activities in the presence of 1.4 to 3.2 M NaCl or 2.3 to 3.2 M KCl. The enzyme hydrolyzed thymidine-5′-monophosphate-
p
-nitrophenyl ester at a rate that increased with NaCl concentration up to 4.8 M. In the presence of both Mg
2+
and Ca
2+
, activity was greatly enhanced. The activity was lost by dialysis against water and low-salt buffer, but it was protected when 10 mM Ca
2+
was added to the dialysis buffer. When the inactivated enzyme was dialyzed against 3.5 M NaCl buffer as much as 68% of the initial activity could be restored. The enzyme exhibited maximal activity at pH 8.5 and at 50°C on DNA and at 60°C on RNA and attacked RNA and DNA exonucleolytically and successively, producing 5′-mononucleotides.
Biphasic culture system for rapid Campylobacter cultivation
Authors: Rollins D M , Coolbaugh J C , Walker R I , Weiss E
Published: January 2020

We developed a biphasic culture system consisting of 4 ml of brucella agar (BA) and 6 ml of brucella broth (BB) in 25-cm2 tissue culture flasks, which were incubated in air (BB/BAa) or in a gas mixture of 5% O2, 10% CO2, and 85% N2 (BB/BAg). These media were also used with a supplement consisting of ferrous sulfate, sodium metabisulfite, and sodium pyruvate and incubated as above (FB/FAa and FB/FAg, respectively). Highly satisfactory growth of Campylobacter jejuni 301 was obtained with all medium-gas phase combinations provided that the number of viable cells in the inoculum was large (greater than or equal to 10(6)/ml). The use of FB/FAa permitted the inoculum to be reduced to 100 cells per ml. With an adjusted gas phase (BB/BAg and FB/FAg), near-optimal growth was obtained from an inoculum of 1 to 10 cells per ml. Under most of these conditions the generation time was approximately 90 min. During the logarithmic growth phase, the cells retained their typical spiral morphology and high motility. These media also proved to be highly satisfactory for the cultivation of fresh isolates as well as other stock strains of Campylobacter. When the broth phase of the cultures, after addition of 15% glycerol, was quickly frozen and maintained at -70 degrees C, all strains thus far examined were readily recoverable and satisfactorily cultivated without additional passage.
Tubular Heads in Bacteriophages from Lactic Streptococci
Authors: Chopin Marie-Christine , Rousseau Micheline
Published: January 2020

Tubular bacteriophage heads were observed in the lysate of two phages from
Streptococcus lactis
obtained from single plaques without mutagenesis. The frequency of appearance of the tubular heads was 2.5 and 16%.
Growth and Sporulation of Entrapped
Bacillus subtilis
Cells
Authors: Baudet Catherine , Barbotin Jean-Noël , Guespin-Michel Janine
Published: January 2020

Growing
Bacillus subtilis
cells were immobilized in
k
-carrageenan gel beads. Growth and sporulation of entrapped cells were studied by two different methods: cell enumeration and transmission electron microscopy. Immobilized growing cells had a shorter generation time than free cells did, whereas sporulation timing was unchanged. When steady state was reached, cell density was very high in gel beads.
Protective Effect of Adonitol on Lactic Acid Bacteria Subjected to Freeze-Drying
Authors: de Valdéz Graciela F. , de Giori Graciela S. , de Ruiz Holgado Aída A. P. , Oliver Guillermo
Published: January 2020

The protective effects of glycerol, adonitol, and four other related polyhydric alcohols on lactic acid bacteria subjected to freeze-drying were examined. The presence of adonitol in the suspending medium markedly protected the viabilities of the 12 stains tested. Dulcitol, mannitol,
m
-inositol, and sorbitol were found to provide little or no protection.
Transformation of
Clostridium acetobutylicum
Protoplasts with Bacteriophage DNA
Authors: Reid Sharon J. , Allcock Errol R. , Jones David T. , Woods David R.
Published: January 2020

Techniques for the transformation of
Clostridium acetobutylicum
protoplasts with bacteriophage DNA are described. Transformation required regeneration of protoplasts and a 2-h eclipse period.
Medium for Isolation and Differentiation of
Vibrio parahaemolyticus
and
Vibrio alginolyticus
Authors: Kourany Miguel
Published: January 2020

Trypticase soy agar supplemented with sucrose, sodium chloride, bile salts, and triphenyltetrazolium chloride is an improved plating medium for the isolation of
Vibrio parahaemolyticus
from samples of seawater, permitting better differentiation of this organism from
Vibrio alginolyticus
and other bacteria.
Phytate Hydrolysis in Rat Gastrointestinal Tracts, as Observed by
31
P Fourier Transform Nuclear Magnetic Resonance Spectroscopy
Authors: Wise Alan , Richards Colin P. , Trimble Mary L.
Published: January 2020

Phytate hydrolysis was followed through rat gastrointestinal tracts by
31
P nuclear magnetic resonance spectroscopy. No phytate hydrolysis products were detected in the diet, stomach, or small intestine. It was concluded that cecal bacteria were responsible for phytate hydrolysis, which continued in the colon and fecal pellet.
Spectrophotometric Method for Determining Titers of Antimycoplasma Metabolism Inhibition Antibody
Authors: Washburn Leigh Rice
Published: January 2020

A new method for determining titers of antimycoplasma metabolism inhibition antibody is described. The assay is performed in microtiter plates as originally described, but the endpoint is determined by comparing the absorbances of the contents of test and control wells spectrophotometrically at 560 nm.
Spatial Distribution of Biochemical Parameters Indicating Biomass and Community Composition of Microbial Assemblies In Estuarine Mud Flat Sediments
Authors: Federle Thomas W. , Hullar Meredith A. , Livingston Robert J. , Meeter Duane A. , White David C.
Published: January 2020

The spatial distribution of communities was examined in estuarine mud flat sediments by the biochemical analysis of the lipids and lipid components extracted from the sediments. Total phospholipid was used as a measure of total biomass, and fatty acids were used as indicators of community composition. Comparisons were made among 2- by 2-m (location) and 0.2- by 0.2-m (cluster) sampling plots by using a nested analysis of variance to design an optimal sampling strategy to define the microbial content of a large, relatively homogenous area. At two of the three stations, a 2- by 2-m plot was representative of the station, but 0.2- by 0.2-m areas were in no case representative of the station. The biomass measured by the extractable phospholipid and the total lipid palmitic acid showed excellent correlation with the fatty acid “signatures” characteristic of bacteria, but showed a lower correlation with the long-chain polyenoic fatty acids characteristic of the microfauna.
Linalyl Acetate Is Metabolized by
Pseudomonas incognita
with the Acetoxy Group Intact
Authors: Renganathan V. , Madyastha K. Madhava
Published: January 2020

Metabolism of linalyl acetate by
Pseudomonas incognita
isolated by enrichment culture on the acyclic monoterpene alcohol linalool was studied. Biodegradation of linalyl acetate by this strain resulted in the formation of linalool, linalool-8-carboxylic acid, oleuropeic acid, and Δ
5
-4-acetoxy-4-methyl hexenoic acid. Cells adapted to linalyl acetate metabolized linalyl acetate-8-aldehyde to linalool-8-carboxylic acid, linalyl acetate-8-carboxylic acid, Δ
5
-4-acetoxy-4-methyl hexenoic acid, and geraniol-8-carboxylic acid. Resting cell suspensions previously grown with linalyl acetate oxidized linalyl acetate-8-aldehyde to linalyl acetate-8-carboxylic acid, Δ
5
-4-acetoxy-4-methyl hexenoic acid, and pyruvic acid. The crude cell-free extract (10,000
g
of supernatant), obtained from the sonicate of linalyl acetate-grown cells, was shown to contain enzyme systems responsible for the formation of linalyl acetate-8-carboxylic acid and linalool-8-carboxylic acid from linalyl acetate. The same supernatant contained NAD-linked alcohol and aldehyde dehydrogenases involved in the formation of linalyl acetate-8-aldehyde and linalyl acetate-8-carboxylic acid, respectively. On the basis of various metabolites isolated from the culture medium, resting cell experiments, growth and manometric studies carried out with the isolated metabolites as well as related synthetic analogs, and the preliminary enzymatic studies performed with the cell-free extract, a probable pathway for the microbial degradation of linalyl acetate with the acetoxy group intact is suggested.
End Products of Glucose Fermentation by
Brochothrix thermosphacta
Authors: Grau Frederick H.
Published: January 2020

Anaerobically,
Brochothrix thermosphacta
fermented glucose primarily to
l
-lactate, acetate, formate, and ethanol. The ratio of these end products varied with growth conditions. Both the presence of acetate and formate and a pH below about 6 increased
l
-lactate production from glucose. Small amounts of butane-2,3-diol were also produced when the pH of the culture was low (≤5.5) or when acetate was added to the growth medium. Radioactive label from [1-
14
C]acetate was incorporated into ethanol and
l
-lactate, implying reversibility of pyruvate-formate lyase. In crude extracts, the following enzymes involved in pyruvate metabolism were demonstrated: lactate dehydrogenase, phosphotransacetylase, acetate kinase, acetaldehyde dehydrogenase (coenzyme A acetylating), ethanol dehydrogenase, pH 6 acetolactate-forming enzyme, and diacetyl (acetoin) reductase. The lactate dehydrogenase did not require fructose-1,6-disphosphate or Mn
2+
for activity.
Partial Purification of
Mucor pusillus
Intracellular Proteases
Authors: Khan M. R. , Blain J. A. , Patterson J. D. E.
Published: January 2020

The intracellular protease extracted from the freeze-dried mycelia obtained after the growth of
Mucor pusillus
at 30°C in corn steep liquor medium was chromatographed on DEAE-A50. Some characteristics of the protease fractions obtained after ion-exchange chromatography were determined and compared with those of the extracellular proteases reported previously. The mycelia were found to contain two acid proteases and an alkaline protease. The ratio of milk clotting to protease activity of one acid protease was greater than that of the other. The electrophoretic pattern of the alkaline protease fraction suggested that it was not a single species, but a mixture of proteolytic enzymes.
House flies (Musca domestica) as possible vectors of Campylobacter fetus subsp. jejuni
Authors: Rosef O , Kapperud G
Published: January 2020

A total of 161 strains of Campylobacter fetus subsp. jejuni were isolated from house flies (Musca domestica). The carrier rates detected were 50.7% in flies captured on a chicken farm and 43.2% in flies from a piggery. The relative prevalences of Campylobacter coli, C. jejuni, and nalidixic acid-resistant thermophilic campylobacters were 90.1, 6.2, and 3.7%, respectively. The results indicate that flies may play a linking role in the epidemiology of Campylobacter infection in humans by transmitting campylobacters from animals to human food.
Effects of Inorganic Particles on Metabolism by a Periphytic Marine Bacterium
Authors: Gordon Andrew S. , Gerchakov Sol M. , Millero Frank J.
Published: January 2020

Measurements were made of adsorption of a periphytic marine bacterium, glucose, and glutamic acid to inorganic particles in seawater and defined bacterial growth medium. Measurements of the metabolism of bacteria were made in the presence and absence of particles by microcalorimetry and radiorespirometry. It was found that hydroxyapatite adsorbs glutamic acid, but not glucose, from the experimental medium. It was also found that hydroxyapatite adsorbs essentially all of the bacteria from the medium when the bacterial concentration is approximately 6 × 10
5
bacteria per ml. If the bacterial concentration is approximately 6 × 10
7
, then only a small fraction of cells become attached. It was therefore possible to select bacterial concentrations and organic nutrients so that bacterial attachment, organic nutrient adsorption, or both would occur in different experiments. In this experimental system the metabolism by attached and nonattached bacteria of adsorbing and nonadsorbing organic nutrients was measured. The results show that bacterial activity in this model system was not enhanced by the particles, regardless of whether the bacteria, the organic nutrient, or both were associated with the surface. In fact, the respiratory activity of the attached bacteria was diminished in comparison with that of free bacteria.
Inability of Microorganisms To Degrade Cellulose Acetate Reverse-Osmosis Membranes
Authors: Ho Leighton C. W. , Martin David D. , Lindemann William C.
Published: January 2020

Operational cellulose acetate reverse-osmosis membranes were examined for evidence of biological degradation. Numerous fungi and bacteria were isolated by direct and enrichment techniques. When tested, most of the fungi were active cellulose degraders, but none of the bacteria were. Neither fungi nor bacteria were able to degrade cellulose acetate membrane in vitro, although many fungi were able to degrade cellulose acetate membrane after it had been deacetylated. Organisms did not significantly degrade powdered cellulose acetate in pure or mixed cultures as measured by reduction in acetyl content or intrinsic viscosity or production of reducing sugars. Organisms did not affect the performance of cellulose triacetate fibers when incubated with them. The inability of the organisms to degrade cellulose acetate was attributed to the high degree of acetate substitution of the cellulose polymer. The rate of salt rejection decline was strongly correlated with chlorination of feed water and inversely with densities of microorganisms. These data suggest that microbial degradation of operational cellulose acetate reverse-osmosis membranes is unlikely.
7 alpha-Dehydroxylation of bile acids by resting cells of an unidentified, gram-positive, nonsporeforming anaerobic bacterium
Authors: Masuda N , Oda H
Published: January 2020

Transformation of bile acids by washed whole cells of strain HD-17, an unidentified gram-positive anaerobic bacterium isolated from human feces, was studied. 7 alpha-Dehydroxylase was produced only during adaptive growth on medium containing 7 alpha-hydroxy bile acids. Both the extent of hydroxylation and the state of conjugation of the bile acids had marked effects on the induction of the enzyme, and the order of the enzyme induction was conjugated cholic acid much greater than cholic acid greater than taurochenodeoxycholic acid greater than or equal to chenodeoxycholic acid. The addition of excess glucose to the growth medium appreciably reduced the enzyme level. The induced enzyme required strict anaerobic conditions for activity and had an optimal pH range of 6.5 to 7.5. In contrast with the induction of the enzyme, the induced enzyme showed a low degree of substrate specificity between cholic acid and chenodeoxycholic acid, with some preference for the former. In addition, the organism contained 3 alpha-, 7 alpha-, and 12 alpha-hydroxysteroid dehydrogenases, and the addition of bile acids to the medium somewhat enhanced the production of the oxidoreductases. The dehydrogenations were obviously stimulated by oxygen as a terminal electron acceptor. The organism also contained bile salt hydrolase.
New medium for improved recovery of coliform bacteria from drinking water
Authors: LeChevallier M W , Cameron S C , McFeters G A
Published: January 2020

A new membrane filter medium was developed for the improved recovery of injured coliforms from drinking water. The new medium, termed m-T7, consists of 5.0 g of Difco Proteose Peptone no. 3, 20 g of lactose, 3.0 g of yeast extract, 0.4 ml of Tergitol 7 (25% solution), 5.0 g of polyoxyethylene ether W-1, 0.1 g of bromthymol blue, 0.1 g of bromcresol purple, and 15 g of agar per liter of distilled water. Additional selectivity may be obtained by aseptically adding 0.1 microgram of penicillin G per ml to the medium after autoclaving. In laboratory studies, m-T7 agar recovered 86 to 99% more laboratory-injured coliforms than did m-Endo agar. m-T7 agar also recovered an average of 43% more verified coliforms from 67 surface and drinking water samples than did the standard m-Endo membrane filter technique. From drinking water, m-T7 agar recovered nearly three times more coliforms than did m-Endo agar. Less than 0.5% of the colonies on m-T7 agar gave false-negative reactions, whereas greater than 70% of the typical yellow colonies from m-T7 agar produced gas in lauryl tryptose broth. Most of the verified coliforms isolated on m-T7 agar belonged to one of the four common coliform genera: Escherichia, 17.6%; Klebsiella, 21.7%; Citrobacter, 17.3%; Enterobacter, 32.2%. The results demonstrate that m-T7 agar is superior to m-Endo agar, especially for the isolation of injured coliforms from drinking water.
Bacterial Activity Associated with the Decomposition of Woody Substrates in a Stream Sediment
Authors: Baker John H. , Morita Richard Y. , Anderson N. H.
Published: January 2020

Ground bark and heartwood from
Alnus rubra
and
Pseudotsuga menziesii
were added to a muddy sediment from a small Oregon stream and incubated in situ. Carbon dioxide and methane production rates were increased by all amendments, the biggest increase being shown with
A. rubra
wood. Except for sediment amended with
A. rubra
wood, nitrogen fixation rates from all treatments (including the control) were approximately 0.1 nmol/g per h throughout the 6-month study period. Contrary to expectations, neither bark had a noticeable adverse effect on microbial activity, but the
A. rubra
wood promoted nitrogen fixation. These results help to explain the faster rate of decomposition of
A. rubra
wood in water compared with that of
P. menziesii
described in the literature. The uptake kinetics of glucose (
V
max
) did not follow the same pattern as gas evolution.
Influence of salts on electrostatic interactions between poliovirus and membrane filters
Authors: Shields P A , Farrah S R
Published: January 2020

Neither solutions of salts nor solutions of detergents or of an alcohol at pH 4 are capable of eluting poliovirus adsorbed to membrane filters. However, solutions containing both a salt, such as magnesium chloride or sodium chloride, and a detergent or alcohol at pH 4 were capable of eluting adsorbed virus. The ability of ions to promote elution of virus at low pH in the presence of detergent or alcohol was dependent on the size of the ions and the ionic strength of the medium. These results suggest that both electrostatic and hydrophobic interactions are important in maintaining virus adsorption to membrane filters. Hydrophobic interactions can be disrupted by detergents or alcohols. It appears that electrostatic interactions can be disrupted by raising the pH of a solution or by adding certain salts. Disruption of either electrostatic or hydrophobic interactions alone does not permit efficient elution of the adsorbed virus at low pHs. However, when both interactions are disrupted, most of the poliovirus adsorbed to membrane filters is eluted, even at pH 4.
Enzyme-Linked Immunosorbent Assay for Quantitative Detection of
Bacillus thuringiensis
Crystal Protein
Authors: Smith Robert A. , Ulrich J. Terry
Published: January 2020

Accurate measurement of the toxic protein crystal produced during deep-tank fermentation of
Bacillus thuringiensis
is critical for optimum process yield. The currently accepted method is a bioassay that requires more time to generate data than to complete the fermentation itself. A noncompetitive enzyme-linked immunosorbent assay has been developed with purified
B. thuringiensis
crystals to generate rabbit antiserum. This technique gives a quantitative crystal protein value with a colorimetric endpoint for either liquids or powders within 4 h of sampling. Reproducibility of this enzyme-linked immunosorbent assay satisfies criteria for use in a commercial process.
Microbial Production of Lysine and Threonine from Whey Permeate
Authors: Ko Young T. , Chipley John R.
Published: January 2020

Extracellular accumulation of lysine and threonine was investigated in modified whey permeate by using
Brevibacterium lactofermentum
ATCC 21086 and
Escherichia coli
ATCC 21151. Whey permeate was prepared from whey by membrane ultrafiltration, and lactose was hydrolyzed by treating permeate with HCl or β-galactosidase. The highest amount of lysine (3.3 g/liter) was produced from a mixture of acid-hydrolyzed whey permeate and yeast extract (0.2%). The highest amount of threonine (3.6 g/liter) was produced from a mixture of whey permeate, (NH
4
)
2
SO
4
(1.4%), yeast extract (0.1%), and Na
2
CO
3
(0.3%).
Fluorogenic selective and differential medium for isolation of fecal streptococci
Authors: Littel K J , Hartman P A
Published: January 2020

Of 44 fluorogenic substrates tested for their ability to differentiate species of fecal streptococci, four yielded species-differentiating reactions. The remaining substrates either yielded uniformly positive, negative, or variable strain-dependent reactions. One substrate, 4-methylumbelliferone-alpha-D-galactoside, was hydrolyzed by Streptococcus bovis and S. faecium and its biotypes. 4-Methylumbelliferone-alpha-D-galactoside and a colorimetric starch substrate were incorporated into the fecal streptococcal selective medium of Donnelly and Hartman (Appl. Environ. Microbiol. 35:576-581, 1978). Three phenotypic groups were identifiable on the new fluorescent gentamicin-thallous-carbonate agar: (i) starch hydrolysis and fluorescence (S. bovis), (ii) no starch hydrolysis but fluorescence (S. faecium and its biotypes), and (iii) no starch hydrolysis or fluorescence (S. faecalis, S. avium, S. equinus, S. mitis, and S. salivarius). Of the presumptive identifications from sewage, swine, and bovine samples, 86% were confirmed as being correct. The new medium has potential application in water, food, environmental, and possibly clinical microbiology.
Detection of T-2 toxin by an improved radioimmunoassay
Authors: Fontelo P A , Beheler J , Bunner D L , Chu F S
Published: January 2020

T-2 toxin in serum, urine, and saline was analyzed by a modified radioimmunoassay procedure. The specimens were added directly to the assay tubes without extraction steps. The reaction between antibody and ligands was optimal at 1 h. Albumin-coated charcoal was used to separate bound from free radioactivity. Quenching, which occurred with hemolyzed specimens, was corrected by a wet oxidation process with 60% perchloric acid and 30% hydrogen peroxide. The shorter incubation times resulted in an assay that takes less than 6 h to complete. The average affinity constant of the antibody (Km) was 1.75 X 10(10) liters/mol. The sensitivity was 1 ng per assay or 10 ng/ml. Among the other trichothecenes tested, only H-T-2 cross-reacted significantly (10.3%).
Activation of cycasin to a mutagen for Saccharomyces cerevisiae by rat intestinal flora
Authors: Mayer V W , Goin C J
Published: January 2020

Genetic test systems involving microorganisms and liver enzyme preparations may be insufficient to detect compounds that require breakdown by enzymes provided by the microbial flora of the intestinal tract. A method is described for providing such activation and for simultaneously testing the potential genetic activity of breakdown products in an indicator organism. Parabiotic chambers containing Saccharomyces cerevisiae genetic test organisms in one chamber were separated by a membrane filter from rat cecal organisms and test chemical contained in the other chamber. The genetic activities of cycasin breakdown products for mutation, gene conversion, and mitotic crossing-over in samples incubated aerobically are reported. Samples containing cycasin alone had a small but clearly increased frequency of genetic damage. Samples containing rat cecal organisms without cycasin showed no increase in genetic activity. Anaerobic incubation resulted in no increase in genetic activity in any of the samples.
Prophage Origin of a Virulent Phage Appearing on Fermentations of
Lactobacillus casei
S-1
Authors: Shimizu-Kadota Mariko , Sakurai Toshizo , Tsuchida Nobuo
Published: January 2020

For protection from the abnormal fermentation of
Lactobacillus casei
S-1 caused by contamination of a virulent phage, φFSV, the origin of this phage was studied. Morphologies, viral structural proteins, and DNA structures of three independent isolates of φFSV were compared with those of φFSW, which is lysogenized in strain S-1. The results showed (i) that the morphology of φFSV phages is indistinguishable from that of φFSW and (ii) that all viral structural components found in φFSW are present in the particles of φFSV's. In addition, restriction endonuclease analyses of viral DNA showed that the
Hin
dIII-digested fragments of φFSW DNA, the sum of which covered at least 94.7% of this phage genome, were conserved in the φFSV DNA digests. Results of Southern filter hybridization of the S-1 and prophage-cured cell (C239) DNAs with φFSV DNA as a probe revealed that C239 had lost most of the φFSV DNA sequence, whereas S-1 had about one copy of the φFSV DNA sequence. These results indicate that virulent phage φFSV is derived from the lysogenized phage φFSW. Therefore, the appearance of φFSV can be eliminated by using the prophage-cured derivative of S-1.
Isolation and characterization of a spiral bacterium from the crypts of rodent gastrointestinal tracts
Authors: Phillips M W , Lee A
Published: January 2020

Spiral-shaped bacteria with a distinctive morphology were isolated from the intestinal mucosa of rats and mice on a campylobacter selective medium using microaerophilic incubation. These bacteria have been shown by other authors to be present in the intestinal tracts of several animal species but have not been cultured previously. The results of electron microscopic examinations and biochemical testing have shown that these organisms do not correspond to any known genus. Colonization experiments with pure cultures in gnotobiotic rodents have shown these bacteria to be mucosa associated, with a particular affinity for intestinal crypts. The pattern of colonization of the intestinal crypts in gnotobiotes known to be free of other mucosa-associated organisms differed from the colonization occurring in conventional animals that possess a normal mucosa-associated flora.