bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbial Response to Drought in a Texas Highplains Shortgrass Prairie
Authors: Thayer D. W.
Published: December 2020

The population of the microbial flora of a mixed blue gramma grass (
Bouteloua gracilis
H. B. K.) and prickly pear (
Opuntia polyacantha
Haw.) prairie near Amarillo, Texas, was studied during 1971 after a severe drought. Bacteria, fungi, and algae were estimated by plate count and terminal dilution procedures. Rates of grass and paper decomposition were determined. The microbial flora of soil associated with bovine-grazed grass did not differ significantly from the flora associated with ungrazed grass, either qualitatively or quantitatively. During drought, a greater number of fungi were found in soil associated with prickly pear than in that associated with blue gramma grass. The microbial biomass decreased one full log between the surface and a depth of 50 cm, and the percentage of anaerobes increased with depth. The maximum numbers of fungi and algae detected were 8 × 10
5
and 6 × 10
4
/g respectively. A linear relationship existed between the microbial biomass and soil moisture. The maximum number of aerobic, heterotrophic bacteria detected was 1.5 × 10
8
viable cells per g of soil.
Specimen Holder to Critical-Point Dry Microorganisms for Scanning Electron Microscopy
Authors: Kurtzman C. P. , Baker F. L. , Smiley M. J.
Published: December 2020

Critical-point drying of microorganisms for scanning electron microscopy can be rapidly and effectively accomplished by use of a newly described specimen holder. Up to eight different samples of spores or vegetative cells are placed between polycarbonate membrane filters in the holder and processed through solvent dehydration and critical-point drying using carbon dioxide without loss or cross contamination of microorganisms. Yeasts, molds, bacteria, and actinomycetes have been successfully processed.
Isolation of
Salmonella enteritidis
Serotype Agona from Eutrophic Regions of a Freshwater Lake
Authors: Cook W. L. , Champion R. A. , Ahearn D. G.
Published: December 2020

Salmonella enteritidis
serotype Agona, which is associated with animal feeds containing fish meal, was isolated consistently from waters influenced by sewage containing poultry processing wastes.
Ehrlich Ascites Tumor Preservation for Fifteen Years—a Simple Method
Authors: Cassel William A. , McCaskill Kathy M.
Published: December 2020

The Ehrlich ascites tumor was preserved for 15 years by adding to it an equal volume of 40% glycerol and placing the preparation directly into a freezer at -60 C.
Tube Culture Method for Viable Counts of
Campylobacter fetus
(
Vibrio fetus
)
Authors: Border Maryon M. , Firehammer B. D. , Myers L. L.
Published: December 2020

A method was developed for making viable counts of
Campylobacter fetus (Vibrio fetus)
in tube cultures using a medium containing alkaline hematin and incubation in a carbon dioxide incubator.
Penicillium stoloniferum
Virus: Large-Scale Concentration and Purification by Polyethylene Glycol
Authors: Detroy R. W. , Still P. E.
Published: December 2020

An experimental procedure developed to concentrate fungal viruses from large volumes of homogenized mycelia with water-soluble polymers, such as polyethylene glycol, possesses advantages over more conventional methods. Concentration of the
Penicillium stoloniferum
fast-moving virus from mycelial homogenates after addition of polyethylene glycol was rapid and produced large quantities of pure virus.
Parabiotic Chamber for Organ Cultures: Improved Model
Authors: Gabridge Michael G.
Published: December 2020

A modified parabiotic chamber for organ cultures is described. It consists of a modified organ culture dish, glass cover slip, a cylinder of semipermeable membrane, and a stainless-steel mesh filter support. Silicone and agar seals were used. Diffusion occurred rapidly and with consistent rates at 37 C when a ratio of 5:2 reservoir to inner chamber volume was used. The device is simple to construct and assemble and allows for continuous observation while maintaining a large surface area available for diffusion. The volumes of the reservoir, inner chamber, and agar base can be varied, and the chamber may be used with a wide variety of cell and organ culture systems.
Diagnosis of California (La Crosse) Encephalitis by Precipitin Techniques: a Prospective Study
Authors: Balfour Henry H. , Edelman Charlene K.
Published: December 2020

Counterelectrophoresis (CEP) and immunodiffusion (ID) were evaluated prospectively as methods for the early and rapid laboratory diagnosis of California encephalitis (CE). CEP and ID studies were done on paired sera from 127 patients with acute central nervous system infections. After the precipitin tests were completed, conventional hemagglutination-inhibition, neutralizing, and complement fixing antibody titers were measured. The CEP system detected antibodies in 7 (41%) of 17 CE patients during their acute illness and in all 17 patients during convalescence. The ID method was less sensitive; 3 of 17 acute sera and 16 of 17 convalescent sera were ID positive. Comparative precipitin studies indicated that La Crosse virus was the infecting California group subtype in all 17 CE patients. Because CEP can be performed in 1.5 h, is at least as sensitive as hemagglutination-inhibition, neutralizing, and complement fixing tests, and can detect prospectively 41% of CE patients during their acute illness, it is recommended as a rapid diagnostic test for CE.
Cold Shock Lethality and Injury in
Clostridium perfringens
Authors: Traci P. A. , Duncan C. L.
Published: December 2020

Several observations have been made in regard to cold shock lethality of
Clostridium perfringens
: (i) loss of viability was not consequence of exposure of the cells to air; (ii) stationary-phase cells were much more resistant to cold shock at 4 C than exponential-phase cells; (iii) at 4 C 96% of an initial population of exponential-phase cells was killed upon cold shock and 95% of the remaining population was killed within 90 min of continued exposure at 4 C; (iv) the minimal temperature differential for detectable cold shock lethality was between 17 and 23 C, and the maximum beyond which lethality was not appreciably increased was between 28 and 33 C. Up to 75% of viable cold-shocked cells were injured, as demonstrated by cold shocking late exponential-phase cells at 10 C and using differential plating procedure for recovery. Repair of injury was temperature dependent, and occurred in a complex medium and 0.1% peptone but not water. Nalidixic acid, chloramphenicol, and rifampin did not inhibit repair of injury.
Toxicity of Short-Chain Fatty Acids and Alcohols Towards
Cladosporium resinae
Authors: Teh J. S.
Published: December 2020

Long-chain saturated fatty acids (C
13
to C
18
) and fatty alcohols (C
12
to C
18
) were well utilized by three different soil isolates of
Cladosporium resinae
as the sole carbon and energy sources in static liquid cultures. Shorter-chain compounds, down to C
5
, did not support growth and were in fact toxic towards the fungus growing on glucose. Rapid and considerable potassium efflux, protein leakage, and inhibition of endogenous respiration were observed in the presence of the shorter fatty acids and alcohols. Possible mechanisms and significance of the toxicity are discussed.
Growth of
Bacteroides fragilis
in Continuous Culture and in Batch Cultures at Controlled pH
Authors: Dalland Eli , Hofstad T.
Published: December 2020

Bacteroides fragilis
NCTC 9343 has been grown in continuous cultures with glucose as growth-limiting factor. At pH 7.0 and at a dilution rate of 0.07 per h, glucose limited growth in concentrations up to 0.6%. Maximal cell yield and productivity were obtained with 0.87% glucose in the inflowing medium. A pH of 7.0 was optimal for growth. With 0.6% glucose in the fresh medium and at pH 7.0, cell yield and productivity were highest at a dilution rate of 0.07 per h and 0.11 per h, respectively. At dilution rates higher than 0.07 per h, glucose was no longer growth limiting, and at dilution rates above 0.11 per h, another compound seemed to have replaced glucose also as energy source. When grown in batch cultures at pH 7.0, the best yields of
B. fragilis
was achieved with 0.6% glucose in the fresh medium. The highest specific growth rate (μm) determined from viable counts was 0.45, corresponding to a mean generation time of 92 min.
Virulence of Venezuelan Equine Encephalomyelitis Virus Subtypes for Various Laboratory Hosts
Authors: Calisher Charles H. , Maness Kathryn S. C.
Published: December 2020

Mice, guinea pigs, and duck embryo cell cultures were inoculated with known subtypes of Venezuelan equine encephalomyelitis (VEE) virus and the attenuated (TC-83) strain of VEE. With the exception of TC-83, all strains were highly pathogenic for suckling mice by either intracranial or intraperitoneal routes of inoculation used. Virulence for older mice and guinea pigs provided a means to distinguish strains. In addition, virulence or lack of virulence for adult mice or guinea pigs provides a rapid method for separating epizootic subtype IB from TC-83 VEE virus isolates.
Simplified Method for the Preparation of Silica Gel Media
Authors: Thatcher Robert C. , Weaver Terry L.
Published: December 2020

A simplified and reliable method for the preparation of a variety of silica gel media is described. The growth of common microorganisms on these media was examined.
Response of Ligated Intestinal Loops in Chickens to the Enterotoxin of
Clostridium perfringens
Authors: Niilo L.
Published: December 2020

Approximately 45-cm length of jejunoileum of 7-week-old chickens was found to be responsive and suitable for testing the enterotoxin of
Clostridium perfringens
by the ligated intestinal loop technique. Injections of 20 to 30 μg of enterotoxin per loop caused positive response of fluid accumulation. Chickens were found to be more convenient and economical for this purpose than other laboratory and domestic animals.
Persistence of Enteroviruses in Lake Water
Authors: Herrmann John E. , Kostenbader Kenneth D. , Cliver Dean O.
Published: December 2020

Two enteroviruses were inactivated more rapidly in a lake than in sterile lake water; then their coat proteins were degraded and, perhaps, used by microorganisms.
Biodegradation of Cyanuric Acid
Authors: Saldick Jerome
Published: December 2020

Cyanuric acid biodegrades readily under a wide variety of natural conditions, and particularly well in systems of either low or zero dissolved-oxygen level, such as anaerobic activated sludge and sewage, soils, muds, and muddy streams and river waters, as well as ordinary aerated activated sludge systems with typically low (1 to 3 ppm) dissolved-oxygen levels. Degradation also proceeds in 3.5% sodium chloride solution. Consequently, there are degradation pathways widely available for breaking down cyanuric acid discharged in domestic effluents. The overall degradation reaction is merely a hydrolysis; CO
2
and ammonia are the initial hydrolytic breakdown products. Since no net oxidation occurs during this breakdown, biodegradation of cyanuric acid exerts no primary biological oxygen demand. However, eventual nitrification of the ammonia released will exert its usual biological oxygen demand.
Growth of Foot-and-Mouth Disease Virus in the Different Layers of Bovine Omasum in Suspended Cultures
Authors: Peleg Ben-Ami , Ron Nily
Published: December 2020

When suspended cultures of bovine omasum were cultured without agitation, the epithelium soon degenerated and foot-and-mouth disease virus multiplied mainly in the corium cells. Five days of preincubation were needed to reach a population of corium cells that could yield virus at a titer of 10
6.70
to 10
6.95
mean tissue culture infective doses per ml. The virus was freely released from the cells into the medium only when the degenerated epithelium was removed from the subepithelial tissue prior to virus inoculation. In agitated cultures, the viability of the epithelium was retained, the virus multiplied in all the layers of the epithelium and was freely released into the medium, and a virus titer of 10
6.95
mean tissue culture infective doses per ml was obtained without preincubation. The omasal laminae could be separated along the line of apposition of the two mucous membranes of the organ. The virus yield from these thin separated membranes was 0.5 to 1.0 log higher than that obtained from nonseparated laminae.
Propylene Oxide as Sterilizing Agent
Authors: Hart A. , Brown M. W.
Published: December 2020

Liquid propylene oxide added to a variety of disinfectant solutions resulted in a significant reduction of the bacterial spore content of these solutions.
Quantitation of the Tetramethyl-
p
-Phenylenediamine Oxidase Reaction in
Neisseria
Species
Authors: Jurtshuk Peter , Milligan Thomas W.
Published: December 2020

The tetramethyl-
p
-phenylenediamine oxidase reaction commonly used in the Kovacs oxidase test was quantitatively estimated for various
Neisseria
species employing standardized resting cell suspensions. This genus of microorganisms exhibited very high tetramethyl-
p
-phenylenediamine oxidase rates comparable to that of
Azotobacter
and
Pseudomonas
, and this reaction was found to be a valid measurement for the respiratory capability possessed by this group of organisms.
Antagonism of Lactic Streptococci Toward
Staphylococcus aureus
in Associative Milk Cultures
Authors: Gilliland S. E. , Speck M. L.
Published: December 2020

The inhibition of growth of
Staphylococcus aureus
by lactic streptococci in associative cultures in milk was not due to hydrogen peroxide produced by the streptococci. Dialyzed whey from the milk culture of lactic streptococci was more inhibitory than dialyzed whey from milk acidified with lactic acid, indicating that material other than lactate was also involved. Analyses of cation and anion exchange fractions from the dialyzed whey showed that only the neutral fraction was inhibitory.
Growth of
Chlamydia trachomatis
in McCoy Cells Treated with Cytochalasin B
Authors: Sompolinsky David , Richmond Shirley
Published: December 2020

When the fungal metabolite cytochalasin B was added to McCoy cells, multinucleated giant cells developed. Monolayers of these cells proved as efficient as irradiated cells for the growth of three different serotypes of
Chlamydia trachomatis
and for the primary isolation of chlamydiae from clinical specimens obtained from patients attending a venereal disease clinic. Cytochalasin treatment of McCoy cells provides a convenient alternative to irradiation and should be of value in the isolation of chlamydiae from the eye and genital tract.
Modified Spinning Top Homogeneous Spray Apparatus for Use in Experimental Respiratory Disease Studies
Authors: Young Harold W. , Larson Edgar W. , Dominik Joseph W.
Published: December 2020

The May spinning top generator was adapted to a modified Henderson tube for producing large aerosol particles (>4 μm) to obtain almost exclusive upper respiratory tract deposition of infectious aerosols in exposed mice. The system was installed in a biological safety cabinet to permit experimentation with pathogens. A novel mechanism utilizing parts from a machinists micrometer and the mechanical stage from a light microscope was developed for the spinning top generator as a means for precisely positioning the liquid feed needle. Aerosol light-scatter properties were continuously analyzed to provide relative measures of particle size distribution and aerosol concentration. When mice were exposed to influenza virus aerosols in which none of the virus was contained in particles with aerodynamic diameters <4 μm, essentially all of the virus was deposited in the upper respiratory tract tissues.
Arthrobacter globiformis
and Its Bacteriophage in Soil
Authors: Casida L. E. , Liu Kang-Chien
Published: December 2020

Bacteriophages in soil for
Arthrobacter globiformis
were rarely detected unless the soil was nutritionally amended and incubated. In amended soil, phage were continuously produced for at least 48 h, and this did not require the addition of host cells. Rod and spheroid stage host cells added to the amended soil encountered indigenous bacteriophage, but added phage did not encounter sensitive indigenous host cells for some time, if at all. The indigenous phage in nonincubated soil seemed to be present in a masked state which was not merely a loose physical adsorption to soil materials but required growth conditions other than lysogeny for them to increase their titers. The possibility is discussed that the indigenous host cells in nonamended soil are present in a nonsensitive spheroid state, with the cells becoming sensitive to the phage in a rate-limiting fashion as nonsynchronous outgrowth occurs for a portion of the spheroid cells.
Microbial Metabolism and Dynamic Changes in the Electrical Conductivity of Soil Solutions: a Method for Detecting Extraterrestrial Life
Authors: Silverman Melvin P. , Munoz Elaine F.
Published: December 2020

The addition of 0.5% glucose solutions to 12 different air-dried soils always resulted in increased electrical conductivity and water-soluble Ca and Mg in the soil solutions. The kinetics and magnitude of these changes for at least two and usually all three of these parameters over a 14-day period were clearly distinguishable from the changes in heat-sterilized controls or unsterilized controls without added glucose. In general, maximal values were achieved more rapidly under aerobic than anaerobic incubation. Some soils (less than half) also showed significant increases in water-soluble Na or K when compared with the controls. The 12 different soils studied represented four general soil groups: I, leached acid upland soils; II, saline alkaline soils; III, nonsaline neutral soils; and IV, high organic soils. Viable counts ranged from 10
4
to 10
7
per cm
3
of air-dried soil. Glucose metabolism by the indigenous soil microbiota was always accompanied by a significant decrease in the pH of soil solutions, but not necessarily by an increase in the viable count. The feasibility of using electrical conductivity and water-soluble Ca and Mg measurements to detect metabolic activity, either alone or in conjunction with other life detection techniques, is discussed.
Deep-Sea Bacteria: Growth and Utilization of Hydrocarbons at Ambient and In Situ Pressure
Authors: Schwarz J. R. , Walker J. D. , Colwell R. R.
Published: December 2020

Microorganisms present in Atlantic Ocean sediment samples collected at a depth of 4,940 m were found to be capable of utilizing hydrocarbons under both ambient and in situ pressures. The rate of utilization under in situ pressure (500 atm) and ambient temperature (20 C) was found to be significantly less compared with hydrocarbon utilization examined under conditions of ambient temperature (20 C) and pressure (1 atm).
Agricultural Plants and Soil as a Reservoir for
Pseudomonas aeruginosa
Authors: Green Sylvia K. , Schroth Milton N. , Cho John J. , Kominos Spyros D. , Vitanza-Jack Vilma B.
Published: December 2020

Pseudomonas aeruginosa
was detected in 24% of the soil samples but in only 0.13% of the vegetable samples from various agricultural areas of California. The distribution of pyocin types of soil and vegetable isolates was similar to that of clinical strains, and three of the soil isolates were resistant to carbenicillin.
Pseudomonas aeruginosa
multiplied in lettuce and bean under conditions of high temperature and high relative humidity (27 C and 80-95% relative humidity) but declined when the temperature and humidity were lowered (16 C, 55-75% relative humidity). The results suggest that soil is a reservior for
P. aeruginosa
and that the bacterium has the capacity to colonize plants during favorable conditions of temperature and moisture.
Culture of
Clostridium pasteurianum
in Defined Medium and Growth as a Function of Sulfate Concentration
Authors: Mallette M. F. , Reece Paul , Dawes E. A.
Published: December 2020

Clostridium pasteurianum
strain W-5 was selected as an anaerobe which may be grown from large inocula in defined media with sulfate as its primary sulfur source. Since it is important to keep inocula small in minimizing transfer of sulfur sources, culture conditions were optimized. The medium devised decreased lag period and generation time when compared with other media, but growth could not be induced consistently with 6 × 10
6
cells per ml or less. Addition of trace elements, chelating agents, reducing agents, metabolites, and spent medium from various stages of growth did not stimulate growth from small inocula. Generation time was 85 min on inoculation with 10
7
or more cells per ml taken from young stocks, but the lag period decreased somewhat with larger inocula. On the other hand, generation time and lag period increased with age of the inoculum. The total yield of cells increased when buffer capacity was increased. Growth of
C. pasteurianum
W-5 was dependent upon sulfate at relatively low sulfate concentrations, and the organism is thus suitable for study of sulfur metabolism. No evidence of a maintenance requirement for sulfate was detected.
Recovery of Murine Leukemia Virus from Large Volumes of Freshly Harvested Culture Fluids by Using a Single Density Gradient
Authors: Sottong P. , Hill P. , Feeney M. , Klecker J. , Johnson K. , Harris R. , Bell C. , Stafford K.
Published: December 2020

Concentration and purification of murine leukemia virus for use as complement fixation antigens was accomplished by using a single density gradient in the model RK ultracentrifuge.
Microflora of Four Fermented Fish Sauces
Authors: Crisan Eli V. , Sands Anne
Published: December 2020

Thirty-nine microorganisms representing 11 species of bacteria, one yeast, and three filamentous fungi were isolated and identified from four fermented fish sauces: nampla, patis, koami, and ounago.
Release of Sediment-Bound Fecal Coliforms by Dredging
Authors: Grimes D. J.
Published: December 2020

Fecal coliform concentrations increased significantly (F test) in the immediate vicinity of a maintenance dredging operation in the Mississippi River navigation channel. Increased counts were attributed to the disturbance and relocation of bottom sediments by dredging and a concomitant release of sediment-bound fecal coliforms.
Effect of Water on the Thermal Death of a Hydrocarbon Bacterium in a Nonaqueous Fluid
Authors: LaRock Paul A.
Published: December 2020

A bacterium that grows in oil was tested for survival at elevated temperatures in menstruums of varying water content. For each doubling of the water concentration, the surviving fraction decreased by a factor of approximately 3.0. A minimum value of 0.02% water is required before enhanced killing occurs.
Decryptification of Acid Phosphatase in Arthrospores of
Geotrichum
Species Treated with Dimethyl Sulfoxide and Acetone
Authors: Cotter David A. , Martel Anita J. , MacDonald Paul
Published: December 2020

Decryptification of acid phosphatase in
Geotrichum
sp. arthrospores was accomplished using acetone or dimethyl sulfoxide treatment. Both dimethyl sulfoxide and acetone irreversibly destroyed the integrity of the spore membranes without solubilizing acid phosphatase.
Selective Filtration in the Isolation of Independent Clones of
Streptomyces
Authors: Parada Jos� L.
Published: December 2020

A single procedure for an efficient discrimination among the different size components of heterogeneous populations of
Streptomyces
spore suspensions is described. Conidia connected by substances of hydrophobic nature make obtaining all the spores in independent units difficult. For the isolation of pure clones, single spore suspensions were prepared by selective filtration through uniform and controlled pore size membranes. Single spore-enriched suspensions may be a useful tool for increasing the yield of auxotrophs, ensuring independent mutation during mutagenic treatments. This procedure can be extended to other sporulating species.
Evaluation of a Medium for the Rapid Recovery of
Escherichia coli
from Shellfish
Authors: Andrews Wallace H. , Diggs Cecile D. , Wilson Clyde R.
Published: December 2020

A medium (A-1) which shortens the time necessary to identify and enumerate
Escherichia coli
found in estuarine water was evaluated for use for recovery of
E. coli
found in shellfish. Productivity of
E. coli
by this medium was comparable to that of the lengthier American Public Health Association method, and the occurrence of false positives was substantially reduced.
Preparation of
14
C-Labeled Sterigmatocystin in Liquid Media
Authors: Hsieh Dennis P. H. , Yang Susie L.
Published: December 2020

14
C-labeled sterigmatocystin was prepared from surface cultures of
Aspergillus versicolor
A-18074 maintained in liquid media by multiple additions of [1-
14
C]acetate to the cultures. The highest yield of 7.75 mg/10 ml was found with a sucrose-asparagine-ammonium medium in which more than 3% of the radioactivity of the added [1-
14
C]acetate was recovered in the purified [ring-
14
C] sterigmatocystin. The method offers an easy way to prepare
14
C-labeled sterigmatocystin for studies of this mycotoxin.
Effect of Ochratoxin and Aflatoxin on Serum Proteins, Complement Activity, and Antibody Production to
Brucella abortus
in Guinea Pigs
Authors: Richard John L. , Thurston John R. , Deyoe Billy L. , Booth Gordon D.
Published: December 2020

The effect of ochratoxin alone and in combination with aflatoxin and
Brucella abortus
antigen on complement activity, serum proteins, and antibody response in guinea pigs was investigated. Ochratoxin did not affect complement activity or antibody response and there was no interaction between ochratoxin and aflatoxin on any of the responses tested. Ochratoxin significantly lowered the level of β-globulin in serum of guinea pigs. There was no significant interaction between aflatoxin and antigen on lowering of the serum albumin levels of guinea pigs.
Characterization of
Bacillus pumilus
E601 Spores After Single Sublethal Gamma Irradiation Treatments
Authors: Parisi A. N. , Antoine A. D.
Published: December 2020

Eighteen survivor strains of
Bacillus pumilus
E601 have been isolated after single sublethal irradiation treatments with
60
Co. Primary isolation was based on the loss of motility and pellicle formation. However, with subsequent subcultivation, eight isolates reverted back to the standard of exhibiting motility and pellicle formation. Characteristics of the isolates include alterations in spore radiation resistance and in the amino acid requirements for spore germination and outgrowth. Other alterations in cultural and physiological characteristics were found. Three of the isolates were asporogenous.
Agar Plate Method for Detection and Enumeration of Alkylbenzenesulfonate-Degrading Microorganisms
Authors: Ohwada Kouichi
Published: December 2020

A simple method for detection and enumeration of alkylbenzenesulfonate (ABS)-degrading microorganisms by using agar plates was developed and used in microbiological studies of coastal marine and polluted river waters. The method depends upon the color responses of neutral red in alkaline medium. Neutral red changes from pink, when it enters into ABS micelles, to yellow, when the ABS is degraded, and does not form micelles. When neutral red-tris(hydroxymethyl)-aminomethane buffer solution and then cationic surfactant solution were sprayed onto the agar surface of ABS-nutrient agar cultures, transparent haloes appeared around the colonies of ABS-degrading microorganisms against a pink background. Viable counts of ABS-degrading bacteria isolated from both seawater and freshwater environments were considerably higher in polluted waters than in less polluted areas. Viable counts of ABS-degrading bacteria averaged 1.5 � 10
5
/ml in samples from the surface water of polluted Tokyo Bay and 3.0 � 10
4
/ml in samples from the surface water of polluted Tamagawa River but were fewer in number in samples from less polluted waters.
Biological Modification of Trichothecene Mycotoxins: Acetylation and Deacetylation of Deoxynivalenols by
Fusarium
spp
Authors: Yoshizawa Takumi , Morooka Nobuichi
Published: December 2020

Attempts were made to elucidate the acetyl transformation of novel trichothecene mycotoxins, 3α,7α,15-trihydroxy-12,13-epoxytrichothec-9-en-8-one (deoxynivalenol) and its derivatives, by trichothecene-producing strains of
Fusarium nivale, F. roseum
, and
F. solani
. In the peptone-supplemented Czapek-Dox medium,
F. roseum
converted 3α-acetoxy-7α,15-dihydroxy-12,13-epoxytrichothec-9-en-8-one (3-acetyldeoxynivalenol) to deoxynivalenol. 3-Acetyldeoxynivalenol was also deacetylated by intact mycelia of the three strains in sugar-free Czapek-Dox medium. The growing
F. nivale
acetylated deoxynivalenol to afford a small amount of 3-acetyldeoxynivalenol. 3α,7α,15-Triacetoxy-12,13-epoxytrichothec-9-en-8-one (deoxynivalenol triacetate) was transformed by the intact mycelium of
F. solani
into 7α,15-diacetoxy-3α-hydroxy-12,13-epoxytrichothec-9-en-8-one (7,15-diacetyl-deoxynivalenol), which was then deacetylated to give 7α-acetoxy-3α,15-dihydroxy-12,13-epoxytrichothec-9-en-8-one (7-acetyldeoxynivalenol). It was noted that the ester at C-7 was not hydrolyzed by the fungal mycelium.
Effect of pH and Sodium Chloride on Growth of
Bacillus cereus
in Laboratory Media and Certain Foods
Authors: Raevuori Marrku , Genigeorgis Constantin
Published: December 2020

The effects of NaCl concentration, pH, and water activity (a
w
) on the ability of vegetative cells of
Bacillus cereus
to initiate aerobic growth in brain heart infusion broth at 30 C were studied in a factorial design experiment. By using multiple regression techniques, equations were derived which related the decimal reduction of the bacterial population to the concentration of NaCl and pH of broth to which the population was exposed. From these equations, the percentage of inoculated cells capable of initiating growth could be calculated. The reliability of these equations in foods was tested in laboratory-processed meat and rice media. The foods were less inhibitory than the broths, so that accurate prediction of growth initiation in foods was not possible by using the developed formulas. The impact of this type of quantitative study on the development of specific microbial standards for foods is discussed. When the NaCl concentration is increased, the a
w
is decreased and, with increased deviation of pH from optimum, more concentrated inoculum of
B. cereus
cells is needed to assure initiation of growth in culture media and foods.
Preparation of Protoplasts of Group H Streptococci (
Streptococcus sanguis
)
Authors: Calandra G. B. , Nugent K. M. , Cole R. M.
Published: December 2020

Stable protoplasts of several strains of group H streptococci (
Streptococcus sanguis
) can be prepared by use of group C streptococcal phage-associated lysin in the presence of 30% raffinose. Sucrose cannot be substituted for raffinose. Protoplast formation did not require the addition of Mg
2+
; however, this cation enhanced their stability. Some other strains, also presumptive group H streptococci, were not sensitive to phage-associated lysin.
Nature of the Surviving Plaque-Forming Unit of Reovirus in Water Containing Bromine
Authors: Sharp D. G. , Floyd R. , Johnson J. D.
Published: December 2020

The initial inactivation of reovirus in water containing 3 to 7 μM bromine as HOBr was very rapid. Electron microscopy revealed extensive physical damage to the virions in as little as 1 min, but none were degraded beyond recognition. As treatment time continued, the reaction rate decreased toward a plateau of resistance, usually at about the 10
-4
survival level; still no particles were lost. Progeny grown from these resistant plaque-forming units (PFU) were no more resistant to HOBr than the parent cultures. Small-number aggregation (adhering groups of two to ten virions counted by electron microscopy) had no detectable effect on the level of persistant PFU. Large aggregates seemed to be involved. Sonic treatment at 20 kHz after bromine exposure increased survival PFU titer 10- to 43-fold. Virus exposed to light centrifugation prior to bromine treatment did not show the plateau of resistance. Surviving PFU sedimented faster in a shallow sucrose gradient than single virions. Large aggregates were apparently too few to be counted by electron microscopy, but their penetration and inactivation must be achieved by any disinfectant chosen to rid water of reovirus.

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Studies on Batch Production of Bacterial Concentrates from Mixed Species Lactic Starters
Authors: Pettersson H. E.
Published: December 2020

Optimum growth conditions for mixed species starter FDs 0172 at constant pH in skim milk, whey, and tryptone medium were investigated. Growth rate and maximum population were optimal at 30 C. pH values between 5.5 and 7.0 did not influence the growth rate and maximum population obtainable. Lactic acid-producing activity declined rapidly after reaching the end of the exponential growth phase. The bacterial balance was found to be influenced by the growth parameters: media, pH, temperature, and neutralizer. Skim milk or whey medium at 25 C, pH 6.5, and neutralized with 20% (vol/vol) NH
4
OH kept the bacterial balance almost constant throughout the cultivation. Grown in tryptone medium at constant pH, the changes in bacterial balance and other metabolic activities were striking compared to the other two media tested. The effect of lactate as an inhibitor was found to be complex, changing with the growth conditions. Concentrates made from mixed species starters FDs 0172, FD 0570, CH 0170, CHs 0170, and T 27 were comparable to controls when cultivated at the optimum conditions found and thereafter centrifuged. Aroma production, proteolytic activity, and CO
2
production did not change significantly compared to controls when cultivated at optimum conditions in skim milk or whey medium.
Continuous Monitoring of pH and Eh in Bacterial Plaque Grown on a Tooth in an Artificial Mouth
Authors: Russell C. , Coulter W. A.
Published: December 2020

Apparatus which enables the simultaneous continuous monitoring of pH and Eh of bacterial dental plaque as it develops on a tooth surface in an artificial mouth is described. Details of the electrodes used, monitoring equipment, and culture conditions are given. Preliminary results are given showing the Eh and pH values of plaque produced in vitro to be in close agreement with readings reported for plaque in vivo. The effect of the incorporation of 1% sucrose in the medium on these parameters is reported and a distinct inverse relationship between pH and Eh recorded.
Polarographic Assay of Hydrogen Peroxide Accumulation in Microbial Cultures
Authors: Dempsey Patrick M. , O'Leary Joseph , Condon Seamus
Published: December 2020

A method is described for determining low concentrations of hydrogen peroxide by using a polarographic oxygen electrode to measure the oxygen released into solution on addition of catalase. A sample can be assayed directly without prior manipulation in 3 min. The method is capable of assaying hydrogen peroxide concentrations as low as 7 μM. The method has proved extremely useful for the assay of hydrogen peroxide secreted into milk by lactic acid bacteria.
Detection and Growth of Enteropathogenic
Escherichia coli
in Soft Ripened Cheese
Authors: Fantasia L. D. , Mestrandrea L. , Schrade J. P. , Yager J.
Published: December 2020

The organism most frequently encountered during the 1971 outbreak of enteropathogenic
Escherichia coli
(EPEC) in soft ripened cheese was a strain that failed to ferment lactose broth within 48 h. Since existing methods for
E. coli
are dependent upon fermentation of this sugar, such strains can remain undetected, particularly when present in low numbers. Therefore, a cultural testing procedure was developed to insure isolation of both lactose-positive and -negative strains. This method used GN broth, modified by substituting lactose and arabinose for glucose and D-mannitol, as an enrichment medium. MacConkey agar, used as a plating medium, was modified by substituting arabinose for half the lactose. The cultural procedure was used in conjunction with a fluorescent antibody method to screen cheese for the presence of presumptive enteropathogenic
E. coli
. Suspected isolates were subjected to further biochemical and serological testing and identified as members of specific serogroups. These methods were used for the analysis of over 2,000 wheels of cheese; over 10% of the samples tested were found to contain strains belonging to six different serogroups associated with diarrheal diseases. No attempt was made to confirm pathogenicity by in vivo tests. Enumeration of
E. coli
in cheese showed that numbers increased during storage. Cheese with less than 10 organisms/g initially increased to over 10
5
at room temperature and over 10
3
at 4 C within 10 days. With higher initial counts, levels up to 10
9
were found at 4 C. These studies showed that the high levels of
E. coli
encountered in these products cannot be used as a direct indicator of post-processing contamination.
Dichlorofluoromethane Inactivates
Saccharomyces cerevisiae
Authors: Middleton J. L. , Marth E. H. , Fennema O.
Published: December 2020

Saccharomyces cerevisiae
was incubated in aerosol cans containing YM broth and dichlorofluoromethane (f-21). The presence and number of viable cells were determined by inoculating (1% vol/vol) YM broth and by the plate count procedure (YM agar). Inactivation of the yeast was greater or more rapid when: (i) the thermodynamic activity (saturation value) of f-21 became greater through increasing the concentration of chemical from 0.5 to 1.5% (wt/wt) in a given volume (20, 40, or 80 ml) of broth, or by holding the concentration of chemical constant but increasing the volume of broth in the test vessel, (ii) the temperature of treatment was increased (7, 22, 37, and 47 C), (iii) samples with 1.5% (wt/wt) f-21 were agitated, (iv) young (8 h) rather than old (36 h or 10 days) cells were treated, and (v) cells were grown in YM broth without, rather than with, glucose. Adjusting the pH (6.3 to 4.0) of broth before treatment, pretreating the substrate with f-21, or distilling the chemical before use had no effect on viability of cells when treated with f-21. Yeast cells inactivated by f-21, chlorine, or heat were more resistant to disruption by sonic treatment than were viable cells.
Use of the Aggregate-Hemagglutination Technique for Determining Exo-Enterotoxin of
Bacillus cereus
Authors: Gorina L. G. , Fluer F. S. , Olovnikov A. M. , Ezepcuk YU. V.
Published: December 2020

The possibility of using the aggregate-hemagglutination technique for detection of
Bacillus cereus
exo-enterotoxin in foodstuffs and culture media is shown. A 0.004-μg quantity of enterotoxin per ml can be detected by this method.
Co-Evolution of a Virus-Alga System
Authors: Cowlishaw John , Mrsa Mark
Published: December 2020

Plectonema boryanum
, a filamentous blue-green alga, was cloned and then allowed to reach a steady state in a quasi-continuous culture in the presence of the algal virus, LPP-1. The culture was maintained for a 3.5-month period during which time at least four distinct culture lysings were evident. After the fourth lysis the culture reached a steady-state level which was identical in its algal concentration to the preinfection level. Upon testing the characteristics of the evolved alga and virus variants, the following was determined: cell variants resistant to both the original virus and the derived virus had evolved, and there was no evidence of lysogeny present among these cells. The evolved virus strains still grew on the parental algal strain, though with altered plaque morphology. Furthermore, they were antigenically similar to the parental virus, and showed no significant difference in adsorption rate or growth characteristics on parental cells. However, a low-grade chronic viral infection persisted in the culture. Rapid re-establishment of a dense, stable culture is apparently the normal laboratory response of a procaryotic cell-virus system.
Protein Content and Amino Acid Composition of Certain Fungi Evaluated for Microbial Protein Production
Authors: Christias C. , Couvaraki C. , Georgopoulos S. G. , Macris B. , Vomvoyanni V.
Published: December 2020

The protein and total amino acid contents of four mycelial fungal strains and one yeast were approximately the same for cultures harvested in the mid-log and early stationary growth phases. It was found that
Fusarium oxysporum
and
Fusarium moniliforme
contained approximately 30% more protein and total amino acids than
Aspergillus niger
. The amino acid composition of mycelial protein compares favorably with that of British Petroleum yeast protein Toprina produced commercially on hydrocarbon substrates.
Fusarium
spp. may be suitable for commercial production of microbial protein, especially when low-cost agricultural or industrial waste products are readily available as energy sources. Genetic manipulation of these fungi, such as induction of mutant strains through irradiation, may be desirable to obtain a mycelial product of improved yield and/or quality.
Proficiency Test Specimens for Water Bacteriology
Authors: Cada Ronald L.
Published: December 2020

A procedure for the preparation and distribution of simulated water specimens for coliform density testing is described. Lyophilization of
Escherichia coli
in a cooked meat-glucose supporting substrate provides stable samples which may be distributed to participants in a proficiency testing program. Logarithmic conversion of the data allows statistical evaluation of the results for inter- and intralaboratory variation. Comparisons between the most probable number and membrane filter techniques indicate no significant difference in the accuracy of these techniques, although the membrane filter technique is more precise.
Length of Incubation for Enumerating Nitrifying Bacteria Present in Various Environments
Authors: Matulewich V. A. , Strom P. F. , Finstein M. S.
Published: December 2020

The effect of incubation time on most-probable-number estimates of autotrophic nitrifying bacteria was investigated by using waters, rooted aquatic plants, sediments, and slimes as inoculum sources. Maximum most probable numbers of the NH
4
+
-oxidizing group were attained in 20 to 55 days (median, 25). Estimates of NO
2
-
oxidizers were highest at termination (103 to 113) days.
Longevity of Dehydrated Violet Red Bile Agar
Authors: Hartman Paul A. , Hartman Philip S. , Frey Kevin T.
Published: December 2020

The length of storage in sealed containers at room temperature did not affect the plating efficiency of violet red bile agar.
Rapid Gas Chromatographic Technique for Presumptive Detection of
Clostridium botulinum
in Contaminated Food
Authors: Mayhew James W. , Gorbach Sherwood L.
Published: December 2020

A simple gas-liquid chromatography end-product assay is reported for butyric and other short-chain fatty acids as presumptive indicators of
Clostridium botulinum
contamination in food.
Rapid Method for Preparing Cell-Free Extracts of
Aspergillus ochraceus
Authors: Sansing G. A. , Davis N. D. , Diener U. L.
Published: December 2020

A rapid method for preparing cell-free extracts of
Aspergillus ochraceus
was developed. Mycelial mats were prefrozen in liquid nitrogen, ground to a fine powder in a cold mortar, and homogenized in an all-glass mechanical homogenizer. This method provided preparations averaging 43.0 mg of protein per g of mycelium (wet weight). The method was fast, efficient, and did not subject the extract to temperatures above 1 C or to heavy metals. The preparation method was suitable for studying a variety of in vitro fungal enzyme systems. Amylase, acid phosphatase, alkaline phosphatase, catalase, fatty acid synthetase, glucose-6-phosphate dehydrogenase, beta-glucosidase, beta fructofuranosidase, and trehalase activities were measurable in the preparations.
Stability of Aflatoxin B
1
and Ochratoxin A in Brewing
Authors: Chu F. S. , Chang C. C. , Ashoor Samy H. , Prentice N.
Published: December 2020

The stability of aflatoxin B
1
and ochratoxin A in brewing was investigated by adding the purified toxins to the raw materials at 1 and 10 μg/g levels during mashing in a conventional micro-brewing process. The results indicate that both toxins are stable to heat and are insensitive to cooker mash treatment. Both mycotoxins were partially removed in the mashing and brewing processes. About 14 to 18% and 27 to 28% of the added toxins were found in the final beers brewed from starting materials containing 1 and 10 μg, respectively, of either toxin per g. The possible route of transmission of mycotoxins into beer is discussed.
Solid-Substrate Fermentor for Ochratoxin A Production
Authors: Lindenfelser L. A. , Ciegler A.
Published: December 2020

A laboratory-scale fermentor designed for solid-substrate fermentation was constructed and tested. Its capacity to produce ochratoxin under varied conditions was determined with wheat as substrate. Ochratoxin yields of 2,000 to 2,500 μg/g of wheat were regularly obtained, and occasionally yields as high as 4,000 μg/g were obtained. The most critical factor in the fermentation was initial substrate moisture content; wheat tempered at 30 to 31% moisture produced the highest yields. Other variables tested were agitation and aeration rates, initial static culture time, and inoculum types and volumes.
Bacteriological Survey of Raw Beef Patties Produced at Establishments Under Federal Inspection
Authors: Surkiewicz Bernard F. , Harris Marshall E. , Elliott R. Paul , Macaluso Joseph F. , Strand Michael M.
Published: December 2020

At the time of manufacture, 76% of 74 sets of raw beef patties collected in 42 federally inspected establishments had aerobic plate counts of 1,000,000 or fewer/g; 84% contained 100 or fewer coliforms/g; 92% contained 100 or fewer
Escherichia coli
/g; and 85% contained 100 or fewer
Staphylococcus aureus
/g (geometric means of 10 patties/set). Salmonellae were isolated from only three (0.4%) of 735 beef patties.
Improved Large-Volume Sampler for the Collection of Bacterial Cells from Aerosol
Authors: White L. A. , Hadley D. J. , Davids D. E. , Naylor R.
Published: December 2020

A modified large-volume sampler was demonstrated to be an efficient device for the collection of mono-disperse aerosols of rhodamine B and poly-disperse aerosols of bacterial cells. Absolute efficiency for collection of rhodamine B varied from 100% with 5-μm particles to about 70% with 0.5-μm particles. The sampler concentrated the particles from 950 liters of air into a flow of between 1 and 2 ml of collecting fluid per min. Spores of
Bacillus subtilis
var.
niger
were collected at an efficiency of about 82% compared to the collection in the standard AGI-30 sampler. In the most desirable collecting fluids tested, aerosolized cells of
Serratia marcescens, Escherichia coli
, and
Aerobacter aerogenes
were collected at comparative efficiencies of approximately 90, 80, and 90%, respectively. The modified sampler has practical application in the study of aerosol transmission of respiratory pathogens.
Inactivation of Viruses and Bacteria by Ozone, With and Without Sonication
Authors: Burleson Gary R. , Murray T. M. , Pollard Morris
Published: December 2020

Selected organisms with public health significance were placed in a reaction chamber for treatment by ozonation, by ozonation and sonication, by sonication, or by sonication during oxygenation. Vesicular stomatitis virus, encephalomyocarditis virus, GDVII virus,
Staphylococcus aureus, Pseudomonas fluorescens, Salmonella typhimurium
, enteropathogenic
Escherichia coli, Vibrio cholerae
, and
Shigella flexneri
were inactivated by treatment with ozone. When microorganisms were suspended in phosphate-buffered saline, they were inactivated rapidly by treatment with ozone. However, microorganisms suspended in secondary effluent from a wastewater treatment plant required longer contact times with ozone for complete inactivation. Simultaneous treatments by ozonation and sonication reduced the contact time for complete inactivation of microorganisms in secondary effluent. Treatment by sonication alone or sonication and oxygenation did not inactivate microorganisms. Therefore, the simultaneous treatment of microorganisms in secondary effluent with ozone and sonication resulted in a synergistic effect.