bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of double violet agar in the isolation of Klebsiella pneumoniae from river water
Authors: Campbell L M , Roth I L , Klein R D
Published: January 2020

A field evaluation of double violet agar for the isolation and presumptive identification of Klebsiella pneumoniae from water has been performed. Water from the North Oconee River, Clarke County, Ga., was cultured for presence of klebsiellae using the membrane filter technique. Colonies were presumptively identified as K. pneumoniae in the basis of their appearance on double violet agar. Such identifications were evaluated using appropriate biochemical tests. Once investigators have become familiar with cultural reactions on the medium, double violet agar can be used to indicate presence of K. pneumoniae in water with greater than 80% accuracy.
Concentration of viruses from large volumes of tap water using pleated membrane filters
Authors: Farrah S R , Gerba C P , Wallis C , Melnick J L
Published: January 2020

A method is described for the efficient concentration of viruses from large volumes of tap water in relatively short time periods. Virus in acidified tap water in the presence of aluminum chloride is adsorbed to a 10-inch (ca. 25.4 cm) fiberglass depth cartridge and a 10-inch pleated epoxy-fiberglass filter in series at flow rates of up to 37.8 liters/min (10 gallons/min). This filter series is capable of efficiently adsorbing virus from greater than 19,000 liters (5,000 gallons) of treated tap water. Adsorbed viruses are eluted from the filters with glycine buffer (pH 10.5) and the eluate is reconcentrated using an aluminum flocculation process. Viruses are eluted from the aluminum floc with glycine buffer (pH 11.5). Using this procedure, viruses in 1,900 liters (500 gallons) of tap water can be concentrated 100,000-fold in 3 h with an average recovery of 40 to 50%.
Toxoid of Clostridium botulinum type F: purification and immunogenicity studies
Authors: Hatheway C L
Published: January 2020

Toxin from Clostridium botulinum type F was recovered from dialysis cultures and partially purifed by: (i) ammonium sulfate and ethanol precipitation; (ii) O-(diethylaminoethyl)-cellulose chromatography; or (iii) diethylaminoethyl-cellulose chromatography followed by O-(carboxymethyl)-cellulose chromatography. Toxin purities as reflected by specific activity were 1.83 X 10(6), 9.8 X 10(6), and 2.0 X 10(7) mouse 50% lethal doses (LD50)/mg of N, respectively, for toxins purified by the three methods. The toxins were converted to toxoids by incubation at 35 C in the presence of 0.3 to 0.45% formalin for 21 to 35 days. Toxoids were immunogenic in guinea pigs, as demonstrated by serum antitoxin response and the immunized animals' resistance to challenge by type F botulinal toxin. The immune response to type F toxoids was lower when toxoids of serotypes A, B, C, D, and E were combined with the type F toxoid than when the type F toxoid only was administered. The toxoid prepared from the most highly purified toxin (method [iii]) conferred the highest immunity in guinea pigs at a given dose level. A relation between serum antitoxin level and resistance to challenge was observed. At least 50% of the groups of guinea pigs with 0.015 antitoxin units or more per ml survived challenge by 10(5) mouse LD50 of type F botulinal toxin. A dose of 3.75 mug of N of the most highly purified type F toxoid in combination with the other five serotypes of botulinal toxoid invoked an immune response in guinea pigs comparable to that considered adequate for the other toxoids.
Recovery of staphylococcal enterotoxin from foods by affinity chromatography
Authors: Genigeorgis C , Kuo J K
Published: January 2020

Extraction, concentration, and serological detection of staphylococcal enterotoxins from foods are laborious and time consuming. By exposing food extracts to an insoluble matrix tagged with specific anti-enterotoxin B, we have been able to recover the toxin from foods in a sensitive and rapid way. After mixing the reagents for 2 h at room temperature, immunoglobulin G antibodies were attached to CNBr-activated Sepharose 4B at pH 8.5 (0.1 M carbonate buffer with 0.5 M NaCl). Sepharose-antibody complex (1 ml) specifically recovered 0.1 to 30 mug of enterotoxin B from 400 ml of food extract (100 g of food) after mixing for 2 h at 4 C. The Sepharose-antibody-toxin complex was washed with 0.02 M phosphate-buffered saline at pH 7.2, and the toxin was dissociated by 2 to 4 ml of 0.2 M HCl-glycine plus 0.5 M NaCl buffer at pH 2.8. The recovered enterotoxin was free of interfering food components and could be detected serologically. Work to couple antibodies A, B, C, D, and E to Sepharose to recover all five toxins in one step is under study.
Co-identity of the refusal and emetic principle from Fusarium-infected corn
Authors: Vesonder R F , Ciegler A , Jensen A H , Rohwedder W K , Weisleder D
Published: January 2020

The structure of vomitoxin isolated from Fusarium-contaminated corn was proved to be 3,7,15-trihydroxy-12,13-epoxytrichothec-9-en-8-one. This same toxin is responsible for the "refusal phenomenon" exhibited by swine fed contaminated corn. In addition, two new substances believed to be trichothecenes were isolated from naturally infected corn. Vomitoxin was also isolated from rice inoculated with F. graminearium NRRL 5883.
Inactivation by bromine of single poliovirus particles in water
Authors: Floyd R , Johnson J D , Sharp D G
Published: January 2020

Quantitative electron microscopy shows that Freon-extracted poliovirus, velocity banded in a sucrose gradient, contains over 95% single particles. This well-dispersed virus reacts quite rapidly with bromine in turbulent flowing water, losing plaque titer at the rate of one log10 unit in 10s at pH 7, 2 C, and at a bromine concentration of 2.2 muM. At 10 and 20 C the rate of disinfection (log10 plaque-forming units per second) is faster, and at both temperatures it increases in approximately linear fashion with increasing bromine concentration. At 2 C such a linear relationship is not observed.
Fermentation of glucose-1-phosphate: a screening test for fermentative Bacteroides species
Authors: Wilkins T D , Walker C B
Published: January 2020

Of 1,504 strains of anaerobic bacteria tested, 544 produced acid from glucose-1-phosphate. Of these, 535 were fermentative strains of Bacteroides; only three fermentative Bacteroides strains were negative. The reaction may be useful for determination of the number of Bacteroides species present in colon content and feces.
Sensitivity of environmental microorganisms to antimicrobial agents
Authors: Van Dijck P , van de Voorde H
Published: January 2020

The sensitivity of different microorganisms, considered as typical representatives of the microflora of soil and water, was established to evaluate the influence of the nonmedical use of antimicrobial agents on bacterial ecology. Only seven strains, six chemoorganotrophs and one chemolithotroph, could be considered as relatively sensitive to the 21 antimicrobial compounds tested. The other 29 microorganisms may be regarded as resistant to most antimicrobial agents. Streptomyces were sensitive to high concentrations of active substances. Broad-spectrum antibiotics showed an effect on environmental bacteria similar to that on human pathogens. Cephalothin stimulated the growth of a Chlorella sp. From these experiments, it appears that spilled antimicrobial agents have little chance of causing an alteration in the microbial ecology.
Factors influencing dark nitrogen fixation in a blue-green alga
Authors: Fay P
Published: January 2020

Nitrogen-fixing activity declines first rapidly and then more gradually when Anabaenopsis circularis is transferred from light into dark conditions. The rate and duration of dark acetylene reduction (nitrogen fixation) depend upon conditions prevailing during the preceding light period. Factors (such as light intensity, CO2 concentration, and supply of glucose), which in the light affect photosynthesis and the accumulation of reserve carbon, have a profound effect on dark nitrogen fixation. Glucose greatly promotes nitrogen fixation in the light and supports prolonged nitrogenase activity in the dark. The results suggest that heterotrophic nitrogen fixation by blue-green algae in the field may be important both under light and dark conditions.
Observations on brilliant green agar with H2S indicator
Authors: Moats W A , Kinner J A
Published: January 2020

Several formulations of brilliant green agar with an added H2S indicator were evaluated. Results were optimum with variations of a basic formula consisting of 40 g of tryptic soy agar (Difco), 8 g of lactose, 8 g of sucrose, 80 mg of phenol red, 1 g of sulfanilamide, 1.5 g of ferric ammonium citrate, 5 g of sodium thiosulfate pentahydrate, and 7 mg of brilliant green dye per liter. Brilliant green dye was added after sterilization of the other components This formulation supported good growth of all of 39 strains of Salmonella tested. Normal biochemical types formed pink colonies with black centers, and an H2S-negative S. choleraesuis formed pink colonies without black centers. Of other bacteria tested, only Enterobacter, Klebsiella, and a few Citrobacter strains showed significant growth in 24 h. When lactose was omitted from the formulation, a lactose-fermenting strain formed pink colonies with black centers, and differentiation of Salmonella from the Enterobacter-Klebsiella groups was equally good. Addition of xylose (4.0 g) and L-lysine hydrochloride (5.4 g) to the above formulation improved differentiation between Salmonella and the few Citrobacter strains that grew and produced more intense blackening in Salmonella colonies. Addition of an H2S indicator to brilliant green agar formulations aided in identification of Salmonella colonies, especially in mixtures with other bacteria. These media were judged to give better differentiation of salmonellae from other bacteria than Hektoen agar with added novobiocin (10 mg/liter).
Relationships between heat resistance and phospholipid fatty acid composition of Vibrio parahaemolyticus
Authors: Beuchat L R , Worthington R E
Published: January 2020

Vibrio parahaemolyticus was grown in tryptic soy broth (TSB) containing NaCl levels of 0.5, 3.0, and 7.5% (wt/vol). Cultures incubated at 21, 29, and 37 C were harvested in late exponential phases and thermal death times at 47 C (D47 c; time at 47 C required to reduce the viable population by 90%) were determined in phosphate buffer containing 0.5, 3.0, and 7.5% NaCl. At a given NaCl concentration in the growth medium, D47 c values increased with elevated incubation temperatures and with elevated levels of NaCl in the heating menstrua. Differences in thermal resistance of cells cultured at a particular temperature were greater between those grown in TSB containing 0.5 and 3.0% NaCl than between those grown in TSB containing 3.0 and 7.5% NaCl. D47c values ranged from 0.8 min (grown at 21 C in TSB with 0.5% NaCl) to 6.5 min (grown at 37 C in TSB with 7.5%, heated in 7.5% NaCl buffer). Methyl esters of major phospholipid fatty acids extracted from cells were quantitated. The ratio of saturated to unsaturated fatty acids in cells grown at a given NaCl concentration increased with elevated incubation temperature. At a particular growth temperature, however, saturated to unsaturated fatty acids ratios were lowest for cells grown in TSB containing 3.0% NaCl.
Double-stranded ribonucleic acid in Agaricus bisporus
Authors: Marino R , Saksena K N , Schuler M , Mayfield J E , Lemke P A
Published: January 2020

Double-stranded ribonucleic acid present in virus-infected mushrooms of Agaricus bisporus has been resolved through polyacrylamide gel electrophoresis into six molecular-weight forms. Identification of these six double-stranded ribonucleic acids in mushrooms by this procedure has proven to be a useful and diagnostic method for viral infection in the cultivated mushroom.
Separation of small ciliate protozoa from bacteria by sucrose gradient centrifugation
Authors: Berk S G , Guerry P , Colwell R R
Published: January 2020

Small ciliate protozoa of the genus Uronema were separated from labeled bacteria by means of a discontinuous sucrose gradient. More than 98% of the radioactivity associated with the bacteria was found in the upper portion of the gradient, whereas the remaining portion of the gradient contained the ciliates.
Distribution of Bdellovibrio bacteriovorus in sewage works, river water, and sediments
Authors: Fry J C , Staples D G
Published: January 2020

Bdellovibrio was found in all liquid phases of the sewage works examined. The predator was also found in all the river sediments and sewage-polluted river waters examined but could not be found in some unpolluted river waters. Bdellovibrio was able to multiply on the high numbers of bacteria present in the aerobic percolating filter film but could not survive in anaerobic sludge. Similarly, the predator was present in the aerobic surface layers of river sediments but not in the anaerobic bottom layers. The major source of Bdellovibrio in the polluted rivers examined were sewage works effluents, and numbers in both river water and sediment were correlated with river water quality. It was unlikely that Bdellovibrio was important in reducing numbers of other bacteria in either sewage or river sediment.
Intestinal microflora in rats: isolation and characterization of strictly anaerobic bacteria requiring long-chain fatty acids
Authors: Morotomi M , Kawai Y , Mutai M
Published: January 2020

Three strains of strictly anaerobic bacteria, isolated from the cecal contents of rats, have strict requirements for long-chain fatty acids. The effect of exogenous fatty acids on the growth and fatty acid composition of the bacteria was examined. Biohydrogenation of linoleic acid into octadecenoic acid was observed. These observations suggest that long-chain fatty acids in the intestine are factors in controlling the localization and the population levels of indigenous bacteria in vivo in rats.
Blockage by acetylene of nitrous oxide reduction in Pseudomonas perfectomarinus
Authors: Balderston W L , Sherr B , Payne W J
Published: January 2020

Suspensions of denitrifying cells of Pseudomonas perfectomarinus reduced nitrate and nitrate as expected to dinitrogen; but, in the presence of acetylene, nitrous oxide accumulated when nitrate or nitrate was reduced. When supplied at the outset in place of nitrate and nitrate, nitrous oxide was rapidly reduced to dinitrogen by cells incubated in anaerobic vessels in the absence of acetylene. In the presence of 0.01 atmospheres of acetylene, however, nitrous oxide was not reduced. Ethylene was not produced, nor did it influence the rate of nitrous oxide reduction when provided instead of acetylene. Cells exposed to 0.01 atmospheres of acetylene for as long as 400 min were able to reduce nitrous oxide after removal of acetylene at a rate comparable to that of cells not exposed to acetylene. Acetylene did not affect the production or functioning of assimilatory nitrate or nitrite reductase in axenic cultures of Enterobacter aerogenes or Trichoderma uride. While exposed to acetylene, bacteria in marine sediment slurries produced measurable quantities of nitrous oxide from glucose- or acetate-dependent reduction of added nitrate. Possible use of acetylene blockage for measurement of denitrification in unamended marine sediments is discussed.
Toxicity and mutagenicity of 2,4,-6-trinitrotoluene and its microbial metabolites
Authors: Won W D , DiSalvo L H , Ng J
Published: January 2020

TNT (2,4,6-trinitrotoluene) of explosive grade is highly toxic to marine forms that included fresh water unicellular green algae (Selenastrum capricornutum), tidepool copepods (Tigriopus californicus), and oyster larvae (Crassostrea gigas), and mutagenic to Salmonella typhimurium. On the basis of mutagenic assays carried out with a set of histidine-requiring strains of the bacterium, TNT was detected as a frameshift mutagen that significantly accelerates the reversion rate of a frameshift tester, TA-98. In contrast, the major microbial metabolites of TNT appeared to be nontoxic and nonmutagenic.
Alpha-galactosidase production and use in a hollow-fiber reactor
Authors: Smiley K L , Hensley D E , Gasdorf H J
Published: January 2020

Soybean milk serves as a base for a variety of beverages designed for consumption in developing countries. Soybean flour contains raffinose and stachyose considered to be responsible for flatulence often associated with these products (J.J. Rackis, D.H. Honig, D.J. Sessa, and F.R. Steggerda, 1970). alpha-Galactosidase, produced on wheat bran, hydrolyzes the galactooligosaccharides of soybean milk.
Effect of Short-Chain Fatty Acids Extracted from Beef Cattle Manure on Germination and Seedling Development
Authors: Schuman G. E. , McCalla T. M.
Published: January 2020

Composted and fresh beef cattle manure samples were extracted with distilled water, acetone, methanol, 2 N sodium hydroxide, 2 N hydrochloric acid, and ether. Bioassay techniques, using the extracts, showed that composted manure extracts had limited effect on seed germination and seeding development of wheat and sorghum. All the extracts of fresh manure, other than distilled water, retarded germination. Acetic, butyric, propionic, valeric, and isovaleric acids were found in ether extracts of fresh manure at average concentrations of 348, 876, 578, 34, and 19 μg/g, respectively, on a dry-weight basis. However, only trace amounts of these acids were present in composted manure. Propionic acid up to the 200-μg/ml level stimulated seedling growth. Acetic and butyric below the 200-μg/ml level had no detrimental or beneficial effects on seedling development. When acetic, butyric, and propionic acids were mixed in equal parts, germination and seedling growth were reduced at all levels (50 to 500 μg/ml).
Effect of dietary aflatoxin on fertility, hatchability, and progeny performance of broiler breeder hens
Authors: Howarth B , Wyatt R D
Published: January 2020

The effects of aflatoxin on egg production, fertility, hatchability, and progeny performance were investigated by feeding dietary aflatoxin at dose levels of 0,5, and 10 mug/g to mature broiler breeder hens for 4 weeks. Sixteen hens were used for each dietary dose level. Egg production decreased significantly during weeks 3 and 4 after initiation of toxin feeding for hens fed 10 and 5 mum of aflatoxin per g of diet respectively. Whereas fertility was not affected by dietary aflatoxin, hatchability of fertile eggs decreased significantly within week 1 of toxin feeding. Hatchability of fertile eggs collected during week 1 of the treatment period was 95.1, 68.9, and 48.5% for the control, 5- and 10-mug/g groups, respectively. At the dose levels used in this study, no latent effects of the aflatoxin or its metabolites were observed on the performance of surviving chicks. Six hens from each experimental groups were necropsied at the end of the 4-week treatment period. These birds exhibited typical symptoms of aflatoxicosis, including enlarged, fatty and friable livers, and enlarged spleens.
Effect of substrate on metabolite production of Alternaria alternata
Authors: Burroughs R , Seitz L M , Sauer D B , Mohr H E
Published: January 2020

Alternariol and alternariol monomethyl ether are commonly associated with weathered grain sorghum. Production of these metabolites and altenuene by isolates of Alternaria alternata was evaluated on various sterile grain substrates. At 35% moisture content and 25 C, metabolite yields were highest on rice, intermediate on sorghums, and lowest on wheat and yellow corn. Fourteen-to 21-day cultures on milled rice were best in terms of ease of metabolite recovery, even though yields were higher on 28-day cultures of rough and brown rice. Metabolite production was reduced when rice was supplemented with yeast extract or yeast extract plus Czapek-Dox broth.
Airborne coliphages from wastewater treatment facilities
Authors: Fannin K F , Spendlove J C , Cochran K W , Gannon J J
Published: January 2020

The emission (from wastewater treatment plants) of airborne coliphages that form plaques on two strains of Escherichia coli was investigated. Two activated-sludge and two trickling-filter plants were studied. Field sampling procedures used large-volume air samplers with recirculation devices. Coliphages were enumerated by a most-probable-number (MPN) procedure. Temperature, relative humidity, windspeed, and presence of sunlight were monitored. Concurrent samples of sewage were taken during each air-sampling run. Average coliphage levels in the airborne emissions of trickling-filter beds and activated-sludge units were 2.84 X 10(-1) and 3.02 X 10(-1) MPN/m3, respectively, for all positive observations, and sewage liquor concentrations from the sources were 4.48 X 10(5) and 2.94 X 10(6) plaque-forming units/liter, respectively, depending upon the E. coli host used for assay. This work establishes minimal airborne-coliphage concentrations from the plants studied. The procedures employed will be useful in evaluating the animal virus levels in these emissions.
Field accumulation of aflatoxin in cottonseed as influenced by irrigation termination dates and pink bollworm infestation
Authors: Russell T E , Watson T F , Ryan G F
Published: January 2020

Aflatoxin accumulation in Deltapine 16 cottonseed, grown in Yuma, Ariz., in a 3-year study, was significantly influenced by the timing of irrigation terminations and by level of pink bollworm infestations. In 1971 and 1972, termination of irrigations by early August resulted in significantly less aflatoxin than in plots where two additional irrigations were applied. Significantly less aflatoxin also was found in the 1971 and 1973 plots where low levels of pink bollworm infestations were maintained.
Incidence of Salmonella spp., Clostridium botulinum, and Vibrio parahaemolyticus in an estuary
Authors: Sayler G S , Nelson J D , Justice A , Colwell R R
Published: January 2020

A study of the incidence of Salmonella spp., Vibrio parahaemolyticus-like organisms, and clostridium botulinum in samples collected at five stations located in the Upper Chesapeake Bay, a major estuary on the Atlantic Coast of the United States, was conducted in December 1973 through December 1974. C. botulinum types B and E were detected in 12.3% of the total sediment samples examined. V. parahaemolyticus was recovered from 10.4% of a total of 86 water, sediment, and suspended sediment samples. Of 131 samples examined for the presence of Salmonella spp., approximately 3% were found to be positive for serologically confirmed Salmonella isolates. Shellfish examined during the investigation were also found to be free of enteric pathogens. The low frequency of occurrence of V. parahaemolyticus was attributed to the low salinities encountered at the sites included in the study. A low incidence of Salmonella spp. in the Upper Chesapeake Bay samples was found, whereas the distribution of C. botulinum appeared to be both random and autochthonous. A strong relationship between presence of potential pathogens and other generally accepted microbiological indicators of pollution was not observed.
Study of Candida ingens grown on the supernatant derived from the anaerobic fermentation of monogastric animal wastes
Authors: Henry D P , Thomson R H , Sizemore D J , O'Leary J A
Published: January 2020

A pellicle-forming yeast, identified as Candida ingens, was found to grow on substrates derived from the anerobic fermentation of monogastric animal wastes. The organism used volatile fatty acids C2 to C6 and ammonia nitrogen. It had a preferential uptake of the acids in increasing order of molecular weight, removing 90% of the total titratable volatile acid. The nonwrinkled pellicle had a doubling time of 3.2 h, and the doubling time of the wrinkled pellicle was 4.2 h. Proximate amino acid and nucleic acid analyses suggested that the organism might be acceptable as a source of single cell protein. Its vitamin B group content compared favorably with that of other yeasts. It contained 6% calcium and 7% phosphorus. It could be useful in removing these minerals from effluents as well as in providing them as nutrients in livestock rations.
Bacteriological quality assessment of fresh marketed lettuce and fennel
Authors: Ercolani G L
Published: January 2020

One-hundred and twenty samples of lettuce and 89 samples of fennel purchased from five retail outlets in the city of Bari (Italy) from October 1973 through September 1975 were examined for viable aerobic bacteria (AB), total coliforms (TC), fecal coliforms (FC), fecal streptococci (FS), and salmonellae. Comparative tests indicated that the results of bacteriological analysis of wash water from either vegetable by a membrane filter technique compared favorably with those of conventional cultural examination of the vegetable tissue for the purpose of providing an indication of the bacteriological quality of the samples. Using the membrane filter technique, 2-year average counts of 6.59 X 10(7) for AB, 5.95 X 10(4) for TC, 6.13 X 10(3) for FC and 2.24 X 10(3) for FS/100 g (fresh weight) were obtained with lettuce; with fennel, the corresponding figures were 2.32 X 10(6) for AB, 7.82 X 10(4) for TC, 7.8 X 10(4) for FC, and 3.15 X 10(3) for FS. Indicator bacteria were present in all samples examined. In addition, 68.3% of the lettuce and 71.9% of the fennel samples yielded one or more of the following Salmonella serotypes: S. schottmuelleri, S. typhimurium, S. thompson, S. dublin, S. typhi, and S. anatum.
Metabolism of acetonitrile and propionitrile by Nocardia rhodochrous LL100-21
Authors: DiGeronimo M J , Antoine A D
Published: January 2020

Six nitrile compounds and two amide derivatives were degraded by Nocardia rhodochrous LL100-21. Acetonitrile, hydroacrylonitrile, and propionitrile were the best sources of carbon and nitrogen for growth, whereas butenenitrile, succinonitrile, and acetamide supported less growth. Acrylonitrile and acrylamide supported growth but only as a source of nitrogen. Gas chromatography of the culture medium revealed a decrease in acetonitrile with the sequential formation of acetamide and acetic acid. Ammonia was also detected by colorimetric procedures. The enzyme system responsible for the hydrolysis of acetonitrile was shown to be intracellular and inducible. The breakdown of acetonitrile by a crude bacterial extract was a two-step enzymatic hydrolysis with acetamide as the intermediate product and acetic acid and ammonia as the final products. Product formation was stoichiometric with substrate disappearance. When propionitrile was the growth substrate, there was complete conversion of the nitrile to propionic acid and ammonia as the major products. The enzymatic breakdown of the propionitrile, although slower than acetonitrile, yielded the corresponding carboxylic acid and ammonia. Propionamide was produced in very small amounts as an intermediate product.
Anaerobic bacteria from the large intestine of mice
Authors: Harris M A , Reddy C A , Carter G R
Published: January 2020

Anaerobic bacteria from the colon of laboratory mice were enumerated and isolated using strict anaerobic techniques. Direct microscopic counts revealed 4.4 X 10(10) organisms in each gram (wet weight) of colon contents. Actual cultural counts averaged 3.2 X 10(10) organisms, which was 73% of the direct microscopic count. The tentatively identified genera were Bacteroides, Eubacterium, Fusobacterium, Lactobacillus, Peptostreptococcus, and Propionibacterium. Strains of Fusobacterium, Lactobacillus, Peptostreptococcus, and Propionibacterium were biochemically homogeneous. Strains of Bacteroides and Eubacterium, on the other hand, were biochemically heterogeneous and were subdivided into several distinct groups. The data indicate that many of the isolates are different from previously described species of the respective genera and may belong to new species.
Influence of sewage discharge on nitrogen fixation and nitrogen flux from coral reefs in Kaneohe Bay, Hawaii
Authors: Hanson R B , Gundersen K
Published: January 2020

Nitrogen fixation was investigated in Kaneohe Bay, Oahu, Hawaii, a subtropical eutrophic estuary, by using the acetylene reduction technique on algal samples. No active, planktonic, N2-fixing blue-green algae or bacteria were observed. However, Calothrix and Nostoc capable of fixing N2 were cultured from navigational buoys and dead coral heads. Nitrogen fixation associated with these structures was greater in the middle sector than in the south and north sectors of the estuary. Experiments demonstrated that the fixation was photosynthetically dependent. Examination of the data showed that there was no significant correlation between rates of nitrogen fixation and concentration of combined nitrogen compounds in the Bay water. Fixation was significantly correlated to the inorganic N/P (atomic) ratio in the south and middle sectors but not in the north sector. The nutrient data indicate there was a flux of combined nitrogen, but not phosphate, from the reef flats.
Effect of ultrasonic waves on the heat resistance of Bacillus spores
Authors: Ordoñez J A , Burgos J
Published: January 2020

The effect of ultrasonic treatment on the heat resistance of Bacillus spores differs widely both with the species and the strain tested. Ultrasonic waves do not affect the heat resistance of some strains, whereas they greatly reduce that of other strains of the same species. The heat-sensitizing effect of ultrasonic waves is more pronounced when short heating periods are used. Ultrasonic treatment does not seem to affect the "Z value".
Phage Typing System for
Salmonella enteritidis
Authors: Gershman M.
Published: January 2020

A system is described for the phage typing of
Salmonella enteritidis.
The system was developed using a number of bacteriophages that were isolated from sewage.
Transductional evidence for plasmid linkage of lactose metabolism in streptococcus lactis C2
Authors: McKay L L , Baldwin K A , Efstathiou J D
Published: January 2020

A lactose-negative (Lac-), proteinase-negative (Prt-) mutant, designated C145 was isolated from Streptococcus lactis C2 after treatment with nitrosoguanidine and ultraviolet irradiation. The mutant appeared to be cured of the prophage(s) present in S. lactis C2 based on non-inducibility by ultraviolet irradiation or mitomycin C. When cleared lysate material from C145 was subjected, to cesium chloride-ethidum bromide (EB) density gradient centrifugation, no plasmid peak was observed, suggesting that C145 was cured of plasmid deoxyribonucleic and (DNA). A histogram showing distribution of contour lengths of circular molecules of DNA from C145, however, revealed the presence of a greatly diminished number of DNA molecules as compared with the parent culture and indicated the absence of the 30 x 10(6) plasmid. Cesium chloride-ethidium bromide gradient profiles from Lac+, Prt- and Lac+ Prt+ transductants of C145 revealed no plasmid peak, but electron microscopy of the fractions normally possessing the satellite band of DNA showed the presence of a new plasmid species having a molecular weight from 20 x 10(6) to 22 x 10(6). This plasmid was lost when the transductants became Lac-. Examination of a plasmid histogram from a spontaneous Lac- Prt- mutants of S. lactis C2 resembled that of C145, with the absence of the 30 x 10(6) plasmid and the presence of the 22 x 10(6) plasmid in Lac+ Prt+ transductants. The results suggest that lactose metabolism is mediated through the 30 x 10(6) plasmid in S. lactis C2 and that the transducing bacteriophage, which is too small to accommodate the entire plasmid, is transferring about two-thirds of the original plasmid through a process termed transductional shortening.
Influence of possible disinfectant transfer on Staphylococcus aureus plate counts after agar contact sampling
Authors: Brummer B
Published: January 2020

Asbestos-vinyl tile floor panels were mopped with three types of chemical disinfectant product, as well as after contact, with the untreated control panel were prepared according to the manufacturer's label instructions. Similar floor panels were inoculated artificially with Staphylococcus aureus. RODAC (replicate organism detection and counting) surface sampling plates were pressed to the disinfectant-treated panels or to the untreated control panel and then immediately pressed to sampling sites on the artificially inoculated floor panels. Plate counts were determined after contact with panels treated with each type of disinfectant, product, as well as after contact with the untreated control panel. Results indicate that disinfectant residues on environmental surfaces do not alter the average plate counts obtained by RODAC samplings.
Acetylene Reduction (Nitrogen Fixation) by
Enterobacteriaceae
Isolated from Paper Mill Process Waters
Authors: Neilson A. H. , Sparell L.
Published: January 2020

Using selective media containing galactitol, over 130
Enterobacteriaceae
have been isolated from paper mill process waters collected from different localities. These bacteria were extensively characterized and tested for acetylene-reducing (nitrogen-fixing) activity under anaerobic conditions. High activity was found in representatives of
Klebsiella pneumoniae, Enterobacter aerogenes, Enterobacter cloacae, Erwinia herbicola, Citrobacter freundii, Citrobacter intermedius
, and
Escherichia coli
. Under argon, nitrogenase synthesis was generally not repressed by 5 mM
l
-glutamate,
l
-aspartate,
l
-leucine or Casamino Acids (0.5 g/liter). In many strains, both the specific activities (nanomoles of C
2
H
4
per minute per milligram of protein) and the activities (nanomoles of C
2
H
4
per minute) had considerably declined after 24 h. In three selected strains, activity in intact cells grown under nitrogen was unaffected by the presence during assay of 10 mM
l
-amino acids or ammonium acetate. All of the strains examined were tolerant towards inactivation of nitrogen-fixing activity by 1.8% (vol/vol) oxygen during assay, and inactivation by up to 10% oxygen was partly reversible. Representatives of the six taxa synthesized nitrogenase in stirred aerobic cultures, though the protein concentrations attained were lower than under anaerobic conditions. It seems reasonable to suggest that under natural conditions, nitrogen fixation is able to contribute significantly to the nitrogen economy of the cells.
Production of sterigmatocystin by Aspergillus versicolor and Bipolaris sorokiniana on semisynthetic liquid and solid media
Authors: Rabie C J , Lubben A , Steyn M
Published: January 2020

Higher yields of sterigmatocystin were obtained with Aspergillus versicolor than with Bipolaris sorokiniana both in liquid and on solid media. The optimum temperature for sterigmatocystin production by A. versicolor was 27 to 29 degrees C and 23 degrees C for B. sorokiniana. In liquid shake cultures, production of sterigmatocystin by B. sorokiniana was negligible, whereas maximal production by A. versicolor was 210 mg/liter. On solid substrates, the highest yields (8 g/kg) were obtained with A. versicolor on still cultures of whole corn supplemented with Soytone.
Effect of disinfectants on variola virus in cell culture
Authors: Tanabe I , Hotta S
Published: January 2020

Twenty kinds of disinfectants were examined for ability to inactivate variola virus. Cytopathic effect and plaque formation on monolayer cultures of an established monkey kidney cell line were used as indicators of virus inactivation. A micromethod using microplate cultures, and not requiring a CO2 incubator, was adopted. The procedures were straightforward, showing good reproducibility. Among the compounds tested, several were found to be superior because of the minimum concentrations required for complete inactivation of virus. The purified viruses were shown to be more sensitive to the compounds than were the crude samples. The virus inactivation kinetics curves were determined by plaque counting. The usefulness of this method for quantitative analysis of disinfecting effect is suggested.
Volatiles produced by microorganisms isolated from refrigerated chicken at spoilage
Authors: Freeman L R , Silverman G J , Angelini P , Merritt C , Esselen W B
Published: January 2020

Volatile components present at spoilage of refrigerated chicken breasts were identified using high-vacuum-low-temperature distillation techniques followed by analysis with combined temperature-programmed gas chromatography and mass spectrometry. A comparison was made of the compounds detected from both irradiated and non-irradiated muscle stored at 2 and 10 degrees C under both aerobic and anaerobic conditions. Isolates were randomly selected from the spoiled poultry, identified, and evaluated for their ability to produce volatile spoilage noted when grown on radiation-sterilized chicken. Several isolates that produced off-odors on sterile chicken breasts were examined. Twenty-two compounds were associated with spoilage. Some of the compounds found on both irradiated and unirradiated samples were considered to play only a minor role in the spoilage aroma or were present in low concentrations, since the aroma of spoiled irradiated chicken lacked the harsh odor notes typical of spoiled unirradiated chicken. Fifteen of the 22 compounds were considered to be unique to unirradiated, aerobically spoiled samples. Nine of these compounds, hydrogen sulfide, methyl mercaptan, dimethyl sulfide, dimethyl disulfide, methyl acetate, ethyl acetate, heptadiene, methanol, and ethanol, were found on chicken spoiled at both 2 and 10 degrees C. xylene, benzaldehyde, and 2,3-dithiahexane were detected only in samples stored at 2 degrees C and methyl thiolacetate, 2-butanone, and ethyl propionate were associated with 10 degrees C spoilage. Fifty-eight isolates randomly selected from fresh, radiation-pasteurized, and unirradiated spoiled poultry were classified taxonomically, and 10 of them, which produced spoilage odors on sterilized chicken breasts, were selected for subsequent analysis of their volatiles. Isolates identified as Pseudomonas putrefaciens and Pseudomonas species that were members of groups I and II of Shewan's classification, as well as Flavobacterium and oxidative Moraxella, produced a number of the compounds found in the aroma of spoiled chicken. A total of 17 compounds were identified. Whereas no isolate produced all of the aroma compounds found in the aroma of spoiled chicken, together they did produce the nine found in unirradiated samples spoiled at either 2 or 10 degrees C, as well as methyl thiolacetate and xylene. Six compounds were present in the volatiles produced by the isolates but were absent in the volatiles identified from spoiled chicken. These were hydrogen cyanide, methyl isopropyl sulfide, 2-propane thiol, methyl propionate, ethyl benzene, and an unidentified compound.
Stability of human enteroviruses in estuarine and marine waters
Authors: Lo S , Gilbert J , Hetrick F
Published: January 2020

Studies of the effects of temperature and salinity on the survival of three enteric viruses (poliomyelitis type 1, echovirus-6, and coxsackievirus B-5) under controlled laboratory conditions and in situ indicate that temperature rather than salinity is the critical factor affecting their stability, in that the higher the temperature the more rapid was the loss of viral infectivity. In the laboratory studies, all three viruses were quite stable at 4 degrees C, with infectious virus still detectable after 46 weeks of incubation. In situ studies on virus survival in free-flowing estuarine or marine waters showed that, although the viruses were more labile in natural waters than in the laboratory studies, they persisted for several months, in some cases during the winter months. At all temperatures and salinities, coxsackievirus B-5 was the most stable, echovirus-6 was intermediate, and poliovirus 1 was the least stable of the viruses tested.
Effects of thermoradiation on bacteria
Authors: Pallas J E , Hamdy M K
Published: January 2020

A 60Co source was used to determine the effects of thermoradiation on Achromobacter aquamarinus, Staphylococcus aureus, and vegetative and spore cells of Bacillus subtilis var. globigii. The rate of inactivation of these cultures, except vegetative-cell populations of B. subtilis, was exponential and in direct proportion to temperature. The D10 (dose that inactivates 90% of the microbial population) value for A. aquamarinus was 8.0 Krad at 25 degrees C and 4.9 Krad at 35 degrees C. For S. aureus, D10 was 9.8 and 5.3 Krad at 35 and 45 degrees C, respectively. Vegetative cells of B. subtilis demonstrated a rapid initial inactivation followed by a steady but decreased exponential rate. The D10 at 25 degrees C was 10.3 Krad, but at 35 and 45 degrees C this value was 6.2 and 3.8 Krad, respectively. Between 0 and 95 Krad, survival curves for B. subtilis spores at 75 degrees C showed slight inactivation, increasing in rat at and above 85 degrees C. The D10 values for spores at 85 and 90 degrees C were 129 and 92 Krad, respectively. Significant synergism between heat and irradiation was noted at 35 degrees C for A. aquamarinus and 45 degrees C for S. aureus. The presence of 0.1 mM cysteine in suspending media afforded protection to both cultures at these critical temperatures. On the other hand, cysteine sensitized B. subtilis spores at radiation doses greater than 100 Krad. The combined effect of heat and irradiation was more destructive to bacteria than either method alone.
Inhibition of methanogenesis in salt marsh sediments and whole-cell suspensions of methanogenic bacteria by nitrogen oxides
Authors: Balderston W L , Payne W J
Published: January 2020

Hydrogen-dependent evolution of methane from salt marsh sediments and whole-cell suspensions of Methanobacterium thermoautotrophicum and Methanobacterium fornicicum ceased or decreased after the introduction of nitrate, nitrite, nitric oxide, or nitrous oxide. Sulfite had a similar effect on methanogenesis in the whole-cell suspensions. In salt marsh sediments, nitrous oxide was the strongest inhibitor, followed by nitric oxide, nitrite, and nitrate in decreasing order of inhibition. In whole-cell suspensions, nitric oxide was the strongest inhibitor, followed by nitrous oxide, nitrite, and nitrate. Consideration of the results from experiments using an indicator of oxidation potential, along with the reversed order of effectiveness of the nitrogen oxides in relation to their degree of reduction ,suggests that the inhibitory effect observed was not due to a redox change. Evidence is also presented that suggests that the decrease in the rate of methane production in the presence of oxides of nitrogen was not attributable to competition for methane-producing substrates.
Bacteria in the Air of Housed Swine Units
Authors: Elliott L. F. , McCalla T. M. , Deshazer J. A.
Published: January 2020

Two housed, swine-growing-finishing units were studied for numbers of total bacteria, fecal coliforms,
Staphylococcus
, and
Salmonella
in the air. At 30.5 and 122 cm from the floor, total colony-forming particles, as tested, averaged 3.4 × 10
5
and 1.3 × 10
5
/m
3
of air, respectively; whereas fecal coliform counts averaged 24 × 10
3
and 1.9 × 10
3
/m
3
of air, respectively. Only 41% of the organisms growing on
Staphylococcus
110 medium tested as
Staphylococcus
. Of 458
Staphylococcus
isolates, 5 were coagulase-positive. No
Salmonella
were detected in the air of the units tested.
Metabolism and growth yields in Bacteroides ruminicola strain b14
Authors: Howlett M R , Mountfort D O , Turner K W , Roberton A M
Published: January 2020

Metabolism of D-glucose by Bacteroides ruminicola subsp. brevis, strain B14, has been examined. Growth yield studies gave molar growth yields, corrected for storage polysaccharide, of approximately 66 g (dry weight)/mol of glucose fermented. The storage polysaccharide amounted to about 14% of the total dry weight, or 55% of the total cellular carbohydrate, at full growth. After correcting glucose utilization for incorporation into cellular carbohydrate, measurement of product formation showed that 1.1 succinate, 0.8 acetate, and 0.35 formate are produced and 0.5 CO2 net is taken up during the fermentation of 1 glucose under the conditions used. The implication of these results with respect to adenosine 5'-triphosphate (ATP) molar growth yield calculations is discussed. If substrate-level phosphorylation reactions alone are responsible for ATP generation, then the ATP molar growth yield must be about 23 g (dry weight)/mol of ATP. Alternatively, if anaerobic electron transfer-linked phosphorylation also occurs, the ATP molar growth yield will be lower.
Penetration of
Rhizopus oligosporus
into Soybeans in Tempeh
Authors: Jurus Alan M. , Sundberg Walter J.
Published: January 2020

Histological observations were made on the penetration of hyphae of
Rhizopus oligosporus
into soybean cotyledons in tempeh, an Indonesian soybean food. Hyphal penetrations averaged one per 1,400 μm
2
(±390 μm
2
) on the curved (outer) cotyledon surface and one per 1,010 μm
2
(±340 μm
2
) on the flat (inner) one. Hyphae infiltrated to a depth of 742 μm, or about 25% of the average width of a soybean cotyledon. This previously unreported degree of penetration offers partial explanation for the rapid physical and chemical changes in soybeans during tempeh fermentation.
Inactivation of Semliki Forest Virus in aerosols
Authors: de Jong J C , Harmsen M , Plantinga A D , Trouwbrost T
Published: January 2020

Purified Semliki forest virus in aerosols is inactivated rapidly at 40% and above 70% relative humidity. At all humidities tested the decay of virus infectivity runs parallel with the decrease in hemagglutination activity, whereas the biological integrity of the virus ribonucleic acid is preserved. Also, free infectious ribonucleic acid is stable after spraying at all relative humidities. Evidence is presented for the hypothesis that above 20% relative humidity, virus inactivation in aersols is mainly due to surface-dependent factors, damaging the virus coat.
Virus and bacteria removal from wastewater by land treatment
Authors: Gilbert R G , Gerba C P , Rice R C , Bouwer H , Wallis C , Melnick J L
Published: January 2020

Secondary sewage effluent and renovated water from four wells at the Flushing Meadows Wastewater Renovation Project near Phoenix, Arizona, in operation since 1967, were assayed approximately every 2 months in 1974 for viruses and enteric bacteria during flooding periods. No viruses of Salmonella sp. were detected in any renovated well water samples, and the numbers of fecal coliforms, fecal streptococci, and total bacteria were decreased by about 99.9% in the renovated well waters after the wastewater was filtered through about 9 m of soil.
Recovery of Yersinia enterocolitica from streams and lakes of California
Authors: Harvey S , Greenwood J R , Pickett M J , Mah R A
Published: January 2020

Stream and lake water from the Mammoth Lakes region of California was sampled for Yersinia enterocolitica. From 10 of the 34 sites examined, organisms were isolated that were biochemically identified as Y. enterocolitica. Only one of the ten strains could be serologically confirmed. This strain was identified as Y. enterocolitica serotype 16. Although an outbreak of enteritis in the area prompted this study, no correlation with gastrointestinal disease could be established since the majority of the strains were untypeable.