bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of Low Numbers of
Escherichia coli
Bacteriophage by Use of the Most Probable Number Method
Authors: Kott Yehuda
Published: December 2020

The estimation of low numbers of the
Escherichia coli
bacteriophage was made possible by use of the most probable number (MPN) method. This method is similar to the technique used for counting coliform bacteria. The statistical results were computed by referring to tables. The method makes it possible to record values as low as two particles per 100 ml of sample. The direct plate count and MPN method were found to be in good correlation for T2 bacteriophage and bulk T bacteriophage in samples obtained from a sewage treatment plant and from contaminated seawater.
Metabolism of Linear Alcohols with Various Chain Lengths by a
Pseudomonas
Species
Authors: Williams Joy P. , Mayberry W. R. , Payne W. J.
Published: December 2020

Pseudomonas
C12B grew on and oxidized linear primary alcohols with even- and odd-numbered carbon chains ranging from C
2
to C
11
. Cell-free extracts of the bacteria contained a nicotinamide adenine dinucleotide-linked dehydrogenase(s) active with these alcohols and with branched primary and linear secondary alcohols as well. Analysis by gas-liquid chromatography of hexane extracts of filtrates of cultures containing mixtures of even-carbon numbered alcohols from C
10
to C
18
revealed that decanol was rapidly utilized, whereas the remainder were slowly dissimilated up to 19 hr and then were rapidly degraded in the next few hours of culture. The validity for these studies of (i) steam distillation as a method for collecting the alcohols from cultures, and (ii) quantitative estimation by gas-liquid chromatographic comparison with an added internal marker, was established. Steam distillation and gas-liquid chromatography were then used to show that failure to demonstrate stoichiometry of sulfate and dodecanol in the alkyl sulfatase reaction in a previous study resulted from contamination of the commercial “Dodecyl Sodium Sulfate, 95%” used with decyl, undecyl, and tetradecyl sulfates.
Effect of Time and Temperature in Assessing Microbial Contamination on Flat Surfaces
Authors: Vesley D. , Keenan K. M. , Halbert M. M.
Published: December 2020

Experiments were performed to investigate incubation time and temperature effects for Rodac agar contact plates applied to bench top surfaces in industrial clean rooms. For studies of general microbial levels, incubation at 32 C for 43 hr was found suitable for Rodac plates containing 15.5 ± 0.1 ml of Trypticase Soy Agar.
Influence of Salts on Foot-and-Mouth Disease Virus
Authors: Fellowes O. N.
Published: December 2020

The effect of sodium and magnesium chloride in 1 and 2
m
concentration at temperatures of 37 and 50 C on type C, strain 149, foot-and-mouth disease virus during storage for 6 days was studied. The exclusively passaged cattle strain and its tissue culture-adapted line were compared. Preparations of the various chemicals and their concentrations were made directly in suspensions of the virus, which, together with untreated control virus suspensions, were stored at indicated temperatures and tested daily for concentration of virus present. Both 1 and 2
m
concentrations of Mg markedly slowed the degradation of the bovine-passaged virus, as compared with untreated virus stored at 37 or 50 C. Such was not the case with 1 and 2
m
concentrations of Na at 37 and 50 C, in which instance the treated virus was degraded faster than the untreated controls at 37 C, and but slightly influenced at 50 C. The tissue culture-adapted virus at the 25th passage was not stabilized by any concentration of chemical additive either at 37 or 50 C, except for 1 and 2
m
concentrations of Na at 37 C, which partially retarded degradation of the virus. After 91 passages of the virus in tissue culture, only a suggestion of the influence of 1 and 2
m
concentrations of Na at 37 C remained to show a stabilizing effect. These responses tend to separate the bovine-passaged virus from the tissue culture-adapted virus under the conditions of this study.
Microorganisms of the Upper Atmosphere
Authors: Fulton John D.
Published: December 2020

The viable micropopulation at three altitudes (152, 1,066, and 1,981 meters) of a land air mass as it traversed an ocean was determined. At the low altitude, a consistent pattern of decrease in numbers of land-originating microorganisms with increasing distance from shore was observed. At the higher altitudes, the observed pattern was one of irregularity. At the lower altitude the percentages of bacteria and fungi were approximately equal near the coast, but as distance from the coast increased, fungi predominated over the bacteria at all sampling locations. The greatest number of different genera of both bacteria and fungi were obtained at or near the coast. Fungi of the genera
Alternaria, Hormodendron, Penicillium
, and
Aspergillus
, and bacteria of the genera
Micrococcus
and
Bacterium
predominated at all altitudes and locations.
Modified Agglutination Test for
Pasteurella tularensis
Authors: Engelfried John J. , Spear Frances
Published: December 2020

Several modifications in technique were incorporated into the standard agglutination test for
Pasteurella tularensis
. Reciprocal shaking of all tubes in a Kahn shaker was introduced to increase the rate of agglutination and quantity of agglutinated cell mass, making it possible to report preliminary results within 4 hr. Increased incubation time at a higher temperature was used to favor the rate of agglutination. A serum control for each serum tested was necessary to detect false positive tests. Finally, a verification procedure with 5% NaCl used as the diluent was instituted to prevent these false positive reactions.
Influence of Cobalt on Fermentative Methylation
Authors: Claridge C. A. , Rossomano V. Z. , Buono N. S. , Gourevitch A. , Lein J.
Published: December 2020

Streptomyces rishiriensis
produces at least five closely related antibiotics. Strain selection yielded a culture producing only the most active component, coumermycin A. Hydrolysis of this antibiotic by barium hydroxide yielded both 5-methyl-pyrrole-2-carboxylic acid and pyrrole-2-carboxylic acid, which could be separated by paper chromatography. Coumermycin A was thus shown to be two fractions, designated A
1
and A
2
depending upon the nature of the pyrrole carboxylic acid portion. The addition of cobalt to the fermentation medium at a level as low as 0.01 μg/ml shifted the fermentation exclusively to the production of coumermycin A
1
. Other ions were ineffective, except nickel, whose activity could be explained by the presence of contaminating cobalt.
Culture of the Rumen Holotrich Ciliate
Dasytricha ruminantium
Schuberg
Authors: Clarke R. T. J. , Hungate R. E.
Published: December 2020

The successful cultivation of the anaerobic ciliate
Dasytricha ruminantium
is described. The cultures were established in a salts medium containing 30% clarified rumen fluid. Sucrose and extract of rumen holotrich protozoa were fed once daily for 2 to 4 hr, and
Dasytricha
was then transferred to medium free from these nutrients. Rumen fluid was essential. Omission of protozoal extract resulted in gradual death of the ciliates. Bovine serum satisfactorily substituted for the protozoal extract, but various rumen bacteria, extract of rumen bacteria, and extracts of plant materials could not. There was a positive correlation between formation of methane in the cultures and growth of the ciliates. It is possible that methane bacteria were ingested, but it is not excluded that survival of both dasytrichs and the methanogenic bacteria depended on a low redox potential of the medium.
Use of Cheese Whey for Vitamin B
12
Production
Authors: Berry E. C. , Bullerman L. B.
Published: December 2020

Within the limits of this study, it was found that 5 ppm of cobalt was adequate to give good levels of vitamin B
12
. The vitamin B
12
precursor 5,6-dimethylbenzimidazole was found to be adequate at 10 ppm in the absence of aeration. In the presence of aeration, a zero level of precursor was found to be most desirable. The analysis of variance showed aeration to be highly significant, and the aeration and precursor interaction to be significant. No other significant effects were observed.
Production of Aflatoxins B
1
and G
1
by
Aspergillus flavus
in a Semisynthetic Medium
Authors: Davis N. D. , Diener U. L. , Eldridge D. W.
Published: December 2020

Isolates of
Aspergillus flavus
produced 0.2 to 63 mg of aflatoxins B
1
and G
1
per 100 ml in a nutrient solution consisting of 20% sucrose and 2% yeast extract. Various factors influencing the fermentation were studied. The maximal amount of toxin was produced by ATCC culture 15548 in 1-liter flasks containing 100 ml of medium incubated as stationary cultures for 6 days at 25 C.
Effect of Corn Steep Liquor on Mycelial Growth and Aflatoxin Production in
Aspergillus parasiticus
Authors: Schroeder Harry W.
Published: December 2020

Total aflatoxin concentrations produced by
Aspergillus parasiticus
, isolate 64-R8, in Czapek's broth fortified with corn steep liquor increased proportionately as the concentration of corn steep was increased from 0.5 to 8.0% (v/v) until maximal growth, as measured by dry mycelial weight, was reached. Thereafter, aflatoxin concentrations declined more rapidly than the rate of autolysis of mycelial material. Data are presented which indicate that the concentration of corn steep liquor also affects the ratio of production of aflatoxin B
1
and B
2
to that of aflatoxin G
1
and G
2
. Further, this ratio also varies with time of incubation. Although both growth of the fungus and aflatoxin production are stimulated by the addition of corn steep to the basic medium, the stimulation of toxin production is much greater than fungus growth.
Salivary Excretion of Coxsackie B-1 Virus in Rabbits
Authors: Madonia John V. , Bahn Arthur N. , Calandra Joseph C.
Published: December 2020

Coxsackie B-1 virus was injected into the ear vein of albino doe rabbits. Saliva and blood samples were taken before the injection of virus and at specific times thereafter. Virus was recovered in the whole saliva when the blood titer was approximately 10
4
TCID
50
per 0.1 ml or greater. The virus could be detected in the saliva as early as 2 min after the initiation of the viremia. The recovered virus was shown to be the same as the injected virus by serological identification of the recovered virus with neutralizing antibody for Coxsackie B-1 virus. These results suggest that virus may be transmitted to other animals in the saliva of animals who are in the viremic phase of infection without infection of the oropharyngeal tissues.
Steroid Mechanisms Affecting Yeast Permeability and Viability
Authors: Smith Rodney F. , Shay Donald E.
Published: December 2020

A synthetic aza-cholestane amine was found to be rapidly lethal to
Saccharomyces cerevisiae
. Lethal action was prevented by pretreating cells with 10
-3
m
uranyl nitrate. Sublethal concentrations of the steroid prevented the uptake of glucose and alanine. This demonstrated one means by which the steroid affected cell permeability, limiting the growth of the organism. Decreases in viability were related to increases in 260 and 280 mμ absorbing materials. Uranyl protection of viability was found to be related to cellular retention of the ultraviolet-absorbing materials. The steroid, dequadin acetate, and cetyl pyridinium chloride were comparable in lethal action and in causing the leakage of cytoplasmic constituents. Loss of viability and cytoplasmic excretion were detected within minutes after cells were exposed to the steroid. The rate or degree of metabolism of glucose by resting cells did not appear to influence steroid action or the sensitivity of the cells to the steroid.
In Vitro Studies on the Antiviral Activity of 1,3-Bis(2-Chloroethyl)-1-Nitrosourea
Authors: Sidwell Robert W. , Arnett G. , Dixon Glen J.
Published: December 2020

Chemotherapy experiments carried out in vitro demonstrated that 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) was active against lymphocytic choriomeningitis virus and had an equivocal antiviral effect on Semliki Forest, herpes simplex, and vaccinia viruses. No antiviral effect was observed with BCNU against western equine encephalomyelitis, polio, and parainfluenza (HA-1) viruses. Activity of the drug was determined by inhibition of viral-induced cytopathogenic effect in KB or chick embryo cells and by reduction of virus titer in cell culture supernatant fluid. Maximal activity against the viruses was observed when drug and virus were incubated together for 30 min prior to addition to cells; essentially no activity could be demonstrated if BCNU and virus were added to cells with no prior incubation.
Long-Term Storage of Bacteriophages of Lactic Streptococci
Authors: Keogh Barbara P. , Pettingill G.
Published: December 2020

Four phage strains representing phages of
Streptococcus lactis, S. cremoris
, and
S. diacetilactis
were selected for the observation of the effect of cold storage on their viability. Phages were stored at 4 C and at -18 C, or were frozen at approximately -70 C and stored at -18 C. They were found to display a high degree of stability with these storage methods. The same phage strains showed good stability to storage at room temperature for 3 weeks after thawing and also to alternate freezing and thawing eight times. Three series consisting of from 23 to 31 lactic streptococcal phage preparations were observed over periods extending up to 6 years, and with only a few exceptions were found to store satisfactorily at -18 C after quick freezing. Although the same phage preparations stored at 4 C were generally somewhat less stable, many were stable when stored by both methods.
Production of Aflatoxin on Rice
Authors: Shotwell Odette L. , Hesseltine C. W. , Stubblefield R. D. , Sorenson W. G.
Published: December 2020

A method has been developed for the production of aflatoxin by growing
Aspergillus flavus
strain NRRL 2999 on the solid substrate rice. Optimal yields, more than 1 mg of aflatoxin B
1
per g of starting material, were obtained in 5 days at 28 C. A crude product containing aflatoxins was isolated by chloroform extraction and precipitation with hexane from concentrated solutions. The crude product consisted of 50% aflatoxin in the following ratio: B
1
-B
2
-G
1
-G
2
, 100:0.15:0.22:0.02. Aflatoxin B
1
was separated from almost all the impurities and from the other aflatoxins by chromatography on silica gel with 1% ethyl alcohol in chloroform. Analytically pure aflatoxin B
1
was recrystallized from chloroform-hexane mixtures.
Liquid Nitrogen Preservation of
Saccharomyces carlsbergensis
and its Use in a Rapid Biological Assay of Pantothenic Acid
Authors: Tsuji Kiyoshi
Published: December 2020

A rapid direct turbidimetric determination of pantothenic acid with the use of
Saccharomyces carlsbergensis
was developed. With a 5.5-hr incubation, the bioassay demonstrated good dose responses within a range up to 0.04 μg/ml of calcium pantothenate. The multivitamin product assay values obtained by the rapid assay method compare well with the values obtained by the standard USP method. β-Alanine interference was reduced to an insignificant level by the incorporation of asparagine in the assay medium. The Upjohn complex products which require Mylase-P enzyme digestion treatments were also satisfactorily assayed.
Mice and Monkeys as Assay Animals for
Clostridium perfringens
Food Poisoning
Authors: Weiss K. F. , Strong D. H. , Groom R. A.
Published: December 2020

Spores and vegetative cells of
Clostridium perfringens
, in combination with meat or starch paste, sterile culture filtrates, lecithinase, and phosphorylcholine, were administered to mice and rhesus monkeys in an attempt both to evaluate the animals as test agents and, if possible, to elucidate the active factors producing food-poisoning symptoms caused by this organsim. Some of the preparations were administered to the monkeys by stomach tube; others, in gelatin capsules which were treated with formaldehyde so that the release of their contents was delayed and presumably reached the intestines of the animals. Any changes in intestinal passage times and in consistency of stools of the animals were observed, and the counts of
C. perfringens
in the feces of the monkeys previous and subsequent to treatment were recorded. The results obtained were inconclusive. Diarrhea occurred only relatively infrequently in both species, regardless of the substance fed or the mode of administration. The changes in intestinal passage times were not great, although in the monkeys there appeared to be a slight trend toward reduction as the magnitude of the bacterial load increased. Phosphorylcholine appeared to have little, if any, effect in reducing intestinal passage time of mice or monkeys. No procedures explored in these experiments could be said to be satisfactory as a means of animal assay for food poisoning strains of
C. perfringens
since typical symptoms did not appear with regularity.
Response of the Extract-Release Volume and Water-Holding Capacity Phenomena to Microbiologically Spoiled Beef and Aged Beef
Authors: Jay James M.
Published: December 2020

The aging of ground beef was effected by storing in gas-impermeable, sterile plastic bags with incubation at 7 and 15 C. Control meat from the same preparations was wrapped in aluminum foil and stored at the same temperature. In three experiments where control meat was tested, aged meat did not attain a log bacterial number of ca. 8.4 per gram until an average of 6 days after this level was reached in control meats. This degree of difference was shown in values for both extract-release volume (ERV) and water-holding capacity. The previously reported ERV value of around 25, which was found to correspond to an average log bacterial number of ca. 8.5 per gram for ground beef allowed to spoil in aluminum foil and freezer paper, was approximated for aged meats, which required an average of 9.7 days to attain this number compared with 4.1 days for unaged meats. Plate count methods indicated the predominant flora of aged beef to be gram-negative, facultatively psychrophilic rods.
U-21,963, a New Antibiotic
Authors: Meyer Curtis E.
Published: December 2020

The isolation and characterization of antibiotic U-21,963 are discussed. This compound is a highly unsaturated monobasic acid with the molecular formula C
9
H
7
NO
3
. The molecular weight is 177. It is dextrorotatory, [α]
D
= +138°, and has a
p
K
a
of 5.1. The ultraviolet absorption spectrum, which showed a maximum at 223 mμ (ε = 15,115), indicates unsaturation α-β to the carboxyl group, and the infrared spectrum suggests the presence of an acetylenic group. Explosive decomposition of U-21,963 at 97 C conforms with the latter. U-21,963 is relatively insoluble in water, but readily soluble in ethyl alcohol, acetone, and halogenated hydrocarbons.
Modified Pagano Levin Medium to Isolate
Candida
Species
Authors: Stedham Michael A. , Kelley Donald C. , Coles Embert H.
Published: December 2020

The use of Pagano Levin medium for primary isolation of
Candida
species from highly contaminated specimens proved unsatisfactory owing to overgrowth by bacteria and fungi. Addition of cycloheximide and chloramphenicol to the medium greatly improved results by inhibiting overgrowth. The additional inhibitors also altered rate of growth and degree of pigmentation reported for some of the
Candida
species.
Comparative Levels and Types of Microbial Contamination Detected in Industrial Clean Rooms
Authors: Favero Martin S. , Puleo John R. , Marshall James H. , Oxborrow Gordon S.
Published: December 2020

The primary objective of this study was to determine quantitatively and qualitatively the predominant types of microbial contamination occurring in conventional and laminar flow clean rooms. One horizontal laminar flow, three conventional industrial clean rooms, and three open factory areas were selected for microbiological tests. The results showed that as the environment and personnel of a clean room were controlled in a more positive manner with respect to the reduction of particulate contamination, the levels of airborne and surface microbial contaminants were reduced accordingly. The chief sources of microbial contamination were associated with the density and activity of clean room personnel. In addition, the majority of microorganisms isolated from the intramural air by air samplers were those indigenous to humans. Studies on the fallout and accumulation of airborne microorganisms on stainless-steel surfaces showed that, although there were no significant differences in the levels of microbial contamination among the conventional clean rooms, the type of microorganism detected on stainless-steel surfaces was consistently and significantly different. In addition, the “plateau phenomenon” occurred in all environments studied. It was concluded that the stainless-steel strip method for detecting microbial accumulation on surfaces is efficient and sensitive in ultra-clean environments and is the most reliable and practical method for monitoring microbial contamination in future class 100 clean rooms to be used for the assembly of spacecraft which will be sterilized.
Gas Exchange of Algae
Authors: Ammann Elizabeth C. B. , Lynch Victoria H.
Published: December 2020

Changes in the oxygen partial pressure of air over the range of 8 to 258 mm of Hg did not adversely affect the photosynthetic capacity of
Chlorella pyrenoidosa
. Gas exchange and growth measurements remained constant for 3-week periods and were similar to air controls (oxygen pressure of 160 mm of Hg). Oxygen partial pressures of 532 and 745 mm of Hg had an adverse effect on algal metabolism. Carbon dioxide consumption was 24% lower in the gas mixture containing oxygen at a pressure 532 mm of Hg than in the air control, and the growth rate was slightly reduced. Oxygen at a partial pressure of 745 mm of Hg decreased the photosynthetic rate 39% and the growth rate 37% over the corresponding rates in air. The lowered metabolic rates remained constant during 14 days of measurements, and the effect was reversible after this time. Substitution of helium or argon for the nitrogen in air had no effect on oxygen production, carbon dioxide consumption, or growth rate for 3-week periods. All measurements were made at a total pressure of 760 mm of Hg, and all gas mixtures were enriched with 2% carbon dioxide. Thus, the physiological functioning and reliability of a photosynthetic gas exchanger should not be adversely affected by: (i) oxygen partial pressures ranging from 8 to 258 mm of Hg; (ii) the use of pure oxygen at reduced total pressure (155 to 258 mm of Hg) unless pressure per se affects photosynthesis, or (iii) the inclusion of helium or argon in the gas environment (up to a partial pressure of 595 mm of Hg).
Antibody Response of Guinea Pigs to Trivalent Parainfluenza Virus Vaccine Prepared from Embryonated Eggs
Authors: DeMeio Joseph L. , DeSanctis Armand N.
Published: December 2020

A trivalent parainfluenza virus vaccine has been tested in guinea pigs. The parainfluenza 2 virus vaccine component was superior in the magnitude of antibody titers, and in the ability to convert animals serologically after two doses of an undiluted or a 10-fold diluted vaccine. The parainfluenza 1 virus vaccine gave a higher percentage of conversion than parainfluenza 3 virus vaccine after administration of two doses of either undiluted or 10-fold diluted vaccine.
Fungistatic Effects of Controlled Atmospheres
Authors: Littlefield Neil A. , Wankier Bartley N. , Salunkhe D. K. , Mcgill J. N.
Published: December 2020

The fungistatic effects of controlled atmospheres composed of increased CO
2
and decreased O
2
was studied in a manner such that the condition of stored fruit was not a factor in the growth of the fungi. Varying concentrations of O
2
and CO
2
were used. The fungi used were
Botrytis alli, Rhizopus nigricans
, and
Penicillium expansum
. The results showed that controlled atmospheres, within the limits of concentrations usable for fruit storage, are effective fungistatic agents.
Action of Lincomycin on Staphylococci
Authors: Bals M. , Bratu Maria
Published: December 2020

On a solid medium, 0.1 to 1 μg/ml of lincomycin hydrochloride had a bacteriostatic effect upon 95 of 100 strains of staphylococci. Using cellophane transfers, we observed a bactericidal effect upon 54 of these strains after 3 to 14 hr of contact with 1 μg/ml. Five staphylococcal strains resistant to 100 μg/ml of lincomycin were also resistant to penicillin G, streptomycin, erythromycin, tetracycline, chloramphenicol (three strains), and rovamycin (three strains). Other staphylococcal strains resistant to methicillin, ampicillin, tetracycline, streptomycin, chloramphenicol, and erythromycin were sensitive to lincomycin.
Elevated-Temperature Technique for the Isolation of
Salmonella
from Streams
Authors: Spino Donald F.
Published: December 2020

With a modified Moore swab for sampling bacteria,
Salmonella
organisms were recovered consistently from surface waters when the enrichment broths of SBG-sulfa and tetrathionate and Brilliant Green Agar plates were incubated at 41.5 C. When an equal portion of the same swab sample was incubated at 37.0 C, no salmonellae were detected. By use of the elevated-temperature technique, salmonellae were recovered from stream sites having relatively low total coliform densities of 2,200 per 100 ml and fecal coliform densities of 220 per 100 ml. These pathogens were isolated in water sampled as far as 73 river miles and 4 days time of travel downstream from the source of pollution under an ice cover that averaged 2.5 ft (76.2 cm) in thickness.
Direct Cord Reading Medium for Isolation of Mycobacteria
Authors: Lorian Victor
Published: December 2020

A study of growth and colony morphology of mycobacteria was performed on 7H10 medium and compared with the same medium to which WR 1339 was added. Collection strains of human, bovine, and atypical mycobacteria, in addition to 1,199 sputa, were planted on both media. The results showed that WR 1339 modifies the growth and colony morphology of human, bovine, atypical group I, and, to a lesser degree, atypical groups II, III, and IV mycobacteria. The great majority of human and bovine strains exhibit definite cords when examined at a magnification of 100 times. The colonies are larger when WR 1339 is added, especially if there is a small number of colonies. The addition of WR 1339 spreads the growth on the surface of the agar, producing a thin but larger colony as compared with 7H10 medium alone on which the colonies grow more vertically, thus producing thick but smaller colonies. WR 1339 spreads the growth, producing thin and transparent colonies where the cords are oriented in uniplane and easily visible directly on the isolation media. Half of the positive sputum cultures were easily identified at 12 days. The presence of typical cords permits a quick screening diagnosis of species directly on the isolation media and, in most instances, elimination of the possibility of atypical or contaminating colonies.
Distribution of Thermophilic Aerobic Sporeforming Bacteria in Food Ingredients
Authors: Richmond B. , Fields M. L.
Published: December 2020

Samples of sugar, starch, spices, and miscellaneous products were tested for thermophilic sporeformers of
Bacillus
to determine the dominant species present. Surface colonies selected at random were identified. Six species of
Bacillus
were isolated:
B. stearothermophilus, B. coagulans, B. licheniformis, B. subtilis, B. circulans
, and
B. pumilus
. Samples of starch and pepper were tested for thermophilic sporeformers of
Bacillus
to determine the distribution of rough and smooth variants. Colonies were classified as rough or smooth variants by colonial characteristics. The distribution of variant forms in these two products was significantly different. Starch samples showed predominantly rough variants; pepper samples showed predominantly smooth variants.
Role of Differential Air Pressure Zones in the Control of Aerosols in a Large Animal Isolation Facility
Authors: Sullivan James F. , Songer Joseph R.
Published: December 2020

The uncontrolled transmission of hog cholera in a large animal isolation facility, designed to control the movement of aerosols within and between individual wings of a multiunit building, indicated the need for a critical study of aerosol behavior under existing conditions of operation. Studies with aerosols of
Escherichia coli
B T3 bacteriophage (T3 coliphage) conclusively demonstrated the impossibility of obtaining the desired control by means of a “static” air balance relationship between adjacent areas within the facility. Modifications needed to provide the desired control of the air-handling system are outlined and discussed.
Nitrogen and Phosphorus Removal from Combined Sewage Components by Microbial Activity
Authors: Finstein M. S.
Published: December 2020

When primary domestic sewage sludge was combined with settled sewage or secondary-treatment plant effluent, synergism resulted. The activity (measured by oxygen uptake, and the removal of Kjeldahl nitrogen and orthophosphate from solution) which resulted from incubating sludge together with settled sewage exceeded the sum of the activities when these components were incubated separately. A similar synergistic effect occurred with sludge and effluent. The sewage sludges were deficient in readily available nitrogen, but no shortage of phosphorus was demonstrated. The addition of ammonium and orthophosphate salts to sludge, in concentrations equivalent to those found in settled sewage and effluent, stimulated sludge oxygen uptake at least 80% as much as settled sewage or effluent. It is suggested that the synergism reflects increased microbial activity resulting from widened carbon-nitrogen and carbon-phosphorus ratios achieved by combining sludge with nutrient-rich settled sewage or effluent.
Inhibition of Microbial Lipases by Fatty Acids
Authors: Smith J. L. , Alford John A.
Published: December 2020

Addition of lard or sodium oleate to the medium used for lipase production by
Pseudomonas fragi
resulted in a decreased accumulation of lipase in the culture supernatant fluid without affecting cell growth. The production and activity of lipase was inhibited by lard, sodium oleate, and the salts of other unsaturated fatty acids. Some divalent cations, Tweens, lecithin, and bovine serum prevented oleate inhibition, but did not reverse it. Similar inhibitory actions were observed with
Geotrichum candidum
lipase, but not with a staphylococcal lipase or pancreatic lipase. A protective effect by protein in crude enzyme preparations is indicated. The ability of oleate to lower surface tension does not appear to be related to its ability to inhibit lipase.
Histochemical Observations on
Mycoplasma
after Staining with Acridine Orange
Authors: Jasper D. E. , Jain N. C.
Published: December 2020

Mycoplasma
colonies and
Mycoplasma
cells in preparations from infected milk and lymph nodes were observed for their fluorescent qualities after treatment with acridine orange.
Mycoplasma
colonies fluoresced brilliant red or red-orange. When treated after exposure to ribonuclease, the colonies fluoresced lime-green. There was no fluorescence when both ribonucleic acid and deoxyribonucleic acid were destroyed by perchloric acid. Detection of
Mycoplasma
in smears of mastitic milk or smears of infected lymph nodes was not definitive because of the large amount of nonspecific ribonucleic acid-rich material present during inflammatory reactions.
Quantitative Assay of
Coxiella burnetii
in Mice
Authors: Schneider Morris D. , Ehrlich Richard , Yamashiroya Herbert M. , Miller Sol
Published: December 2020

Experimental data are presented which demonstrate that the complement-fixing antibody response in individual mice can be used for quantitative assay of
Coxiella burnetii
. The method allows the replacement of a single guinea pig with a single mouse, thus resulting in considerable savings in caging requirements and animal costs.
Role of Lipid in the Protection of
Staphylococcus aureus
Against Trichlorophenol in Mixed Culture
Authors: Truby C. P. , Bennett E. O.
Published: December 2020

The sensitivities of
Proteus mirabilis, Salmonella schottmuelleri, Aerobacter aerogenes
, and
Staphylococcus aureus
to 2, 4, 6-trichlorophenol in sodium borate were studied. It was demonstrated that these gram-negative organisms can protect
S. aureus
from the effect of the phenol in mixed culture. There is a direct correlation between this protective effect and the quantity of total lipid extracted from the gram-negative organisms. The distribution coefficient between trichlorophenol and the lipid of the cells is related to the sensitivity and capacity to protect
S. aureus
in mixed culture. Hydrogen bonding between the cell's lipid and the phenolic compound is discussed as a possible mechanism which determines a cell's response to the inhibitor.
Incidence of Mesophilic
Clostrodium
Spores in Raw Pork, Beef, and Chicken in Processing Plants in the United States and Canada
Authors: Greenberg R. A. , Tompkin R. B. , Bladel B. O. , Kittaka R. S. , Anellis A.
Published: December 2020

The anaerobic film pouch technique was used to quantitate and isolate clostridial spores in 2,358 samples of raw meat (1,078 of chicken, 624 of beef, 656 of pork). Of 19,727 putrefactive anaerobic (PA) sporeformers isolated, 1 was confirmed by mouse protection testing to be
Clostridium botulinum
type C. This isolate was obtained from a Western Canada chicken sample which contained 5.33 clostridia per gram. These data indicate a very low incidence of botulinal contamination in raw meats at the packing-plant level (0.042% of 2,358 samples) and an almost 20,000:1 ratio of nonbotulinal PA sporeformers to mesophilic
C. botulinum
spores. The mean level of PA contamination was 2.8 PA sporeformers per gram of meat; 77% of the samples contained three or less PA sporeformers per gram. Small but statistically significant differences in the incidence of clostridial spores were noted for season, geographical region, and type of meat.
Acetaldehyde Utilization by
Leuconostoc
Species
Authors: Keenan T. W. , Lindsay R. C. , Day E. A.
Published: December 2020

Single-strain cultures of
Leuconostoc dextranicum
and
L. mesenteroides
were found to be capable of utilizing acetaldehyde in both acidified and nonacidified milk cultures at 21 and 30 C.
L. dextranicum
utilized acetaldehyde more rapidly than
L. mesenteroides
when the
p
H of the medium was near that of normal ripened lactic dairy cultures. Acetaldehyde production and utilization varied widely among different two-strain cultures of lactic streptococci and leuconostocs. The concentration of acetaldehyde in ripened single-strain lactic streptococcal cultures was lowered by adding a large inoculum of ripened
L. citrovorum
culture and continuing incubation at 21 or 5 C.
Conversion of C
14
-Labeled Substrates to Volatile Fatty Acids by the Rumen Microbiota
Authors: Wallnöfer P. , Baldwin R. L. , Stagno E.
Published: December 2020

The fermentation of uniformly labeled glucose-
C
14
, glucose-
1-C
14
, -
2-C
14
, and -
6-C
14
, xylose-
1-C
14
, cellulose-
1-C
14
, -
2-C
14
, and -
6-C
14
, and lactate-
2-C
14
by rumen fluids from cows fed all-hay, hay and concentrate (50:50), and all-concentrate diets was investigated. The results obtained suggested that the Embden-Meyerhof glycolytic pathway is the major pathway of hexose utilization, that the major pathway of xylose fermentation involves hexose synthesis, and that the contributions of the nonrandomizing (acrylate) pathway of propionate formation during glucose, xylose, and cellulose fermentations are 4.5, 8.0, and 10.5%, and 24.6, 25.8, and 17.2%, respectively, by rumen fluids from the cows fed all-hay and all-concentrate rations.
Western Equine Encephalomyelitis Vaccine Produced in Chick Embryo Cell Cultures
Authors: Robinson David M. , Berman Sanford , Lowenthal Joseph P. , Hetrick Frank M.
Published: December 2020

A method was developed for production of a freeze-dried Western equine encephalomyelitis vaccine from virus propagated in chick embryo cell culture monolayers maintained with a serum-free medium. A sufficient concentration of virus accumulated in the cell culture fluids prior to the occurrence of viral cytopathology to permit the production of a vaccine relatively free from serum and cellular proteins. Inoculation with two mouse
ld
50
doses of virus per 100 tissue culture cells was found to yield reproducible high virus titers at a convenient harvest time. These harvests were inactivated at 22 C by 0.05% formalin within 48 hr. Potency test results, as measured by the protection of immunized guinea pigs against an intracerebral virus challenge, indicated that the vaccine produced from the virus propagated in cell culture was equal in potency to a lot of whole chick embryo vaccine used to immunize laboratory and field workers subject to a high risk of infection.
Action of Chloramphenicol and Its Isomers on Secondary Biosynthetic Processes of
Bacillus
Authors: Weinberg Eugene D. , Tonnis Sue M.
Published: December 2020

Chloramphenicol or its isomers, if supplied within 4 hr after the addition of Mn
+2
, prevented sporulation of
Bacillus megaterium
at concentrations that partially inhibited protein synthesis but which were neither bacteriostatic nor bactericidal. Likewise, sub-bactericidal quantities of the compounds, if supplied within 2 hr after the addition of Mn
+2
, suppressed formation of bacitracin by
B. licheniformis
. In contrast to previous reports that chloramphenicol is less active than its isomers against sporulation and peptide formation, the results of the present study indicated that the order and extent of these activities of the compounds is similar to that of their ability to prevent growth and to suppress protein synthesis; i.e.,
d
(-)-threo >
l
(+)-erythro >
d
(-)-erythro.
Formation of the Blue Pigment Indigoidine by Phytopathogenic
Erwinia
Authors: Starr Mortimer P. , Cosens Gladys , Knackmuss Hans-Joachim
Published: December 2020

Most cultures belonging to the “
Erwinia chrysanthemi
group” of soft-rot bacteria form traces of a blue, extracellular, water-insoluble pigment. This pigment is generally not found in cultures of the other members of the genus
Erwinia
. The blue substance has been isolated and purified from three members of the
E. chrysanthemi
group; it has been identified as indigoidine, 5,5′-diamino-4,4′-dihydroxy-3,3′-diazadiphenoquinone-(2,2′).
Inhibition of Swarming of
Proteus
by Sodium Tetradecyl Sulfate, β-Phenethyl Alcohol, and
p
-Nitrophenylglycerine
Authors: Kopp Rudolf , Müller Johannes , Lemme Renate
Published: December 2020

The effects of sodium tetradecyl sulfate (STS), β-phenethyl alcohol (PEA), and
p
-nitrophenylglycerol (PNPG) on motility, swarming, flagellation, and growth of
Proteus
were examined. Growth-inhibitory concentrations (GIC) and swarming-inhibitory concentrations (SIC) were determined. A characterization of the swarming-inhibitory efficacy of these compounds was based on their GIC/SIC ratio and their concentration inhibition curves. Using the homologous series of sodium alkyl sulfates as a standard reference, we showed that PNPG was more effective than STS, which was the most effective of the homologous series. PEA was less effective than sodium decyl sulfate but more effective than sodium octyl sulfate. Motility tests in liquid medium and electron microscope investigations indicated that the modes of action of the three compounds, all of which effectively inhibit the swarming of
Proteus
, are different. Whereas STS and PEA inhibit swarming by inhibition of motility, PNPG seems to act on the swarming mechanism sensu strictori, without impairment of motility. STS immobilizes by inhibition of flagellum formation or by some lytic action on the flagella already synthesized. PEA acts by impairing flagellar function, but leaves the flagella morphologically intact.
Comparison of Acetate Differential Agar with Sellers Citrate-Mannitol-Agar
Authors: Cordaro Joseph T. , Ball Robert J.
Published: December 2020

A total of 245 isolates of
Escherichia coli
(paracolons) were employed in comparing the use of acetate differential agar (ADA) with the simple test described by Sellers to eliminate these organisms from consideration as enteric pathogens. At 18 hr after the media were inoculated, 83% of the isolates produced a positive citrate reaction on Sellers citrate-mannitol-agar (SCM) and 7% gave a positive reaction on ADA. At 24 hr, 92% of the cultures were positive on SCM versus 42% on ADA. At 48 hr, 244 (99.6%) of the isolates were positive on SCM, whereas a 72-hr incubation period was required for equal results with ADA. One isolate failed to grow on either medium.
Effect of Air Ions on Submicron T1 Bacteriophage Aerosols
Authors: Happ John W. , Harstad J. Bruce , Buchanan Lee M.
Published: December 2020

The effect of a high concentration of ionized air molecules on sampling T1 phage aerosols of submicron particle size was evaluated by comparing the phage recoveries of all-glass impingers (AGI-4) and type 6 filter papers. Sampler recoveries of all ionized aerosols were less than the recoveries of nonionized control aerosols. These reductions in recovery were greater with positive ions than with negative ions or ions of mixed polarity. The AGI-4 allowed considerable slippage, which was not affected by the air ions. Type 6 filter paper recoveries were less than AGI-4 recoveries. The air ions did not appear to affect the aerosol particle size as determined by an electron microscope.
Effect of Mg
++
on the Activity of Vancomycin Against
Escherichia coli
Authors: Russell A. D. , Thomas I. L.
Published: December 2020

Mg
++
ions alleviate the inhibitory effect of vancomycin on
Escherichia coli
. This is not due to the formation of an antibacterial-inactive complex. It is suggested that vancomycin and Mg
++
compete for a receptor site, or sites, on (or in) the bacterial cell.
Changes in the Microflora of Vacuum-packaged, Irradiated Petrale Sole (
Eopsetta jordani
) Fillets Stored at 0.5 C
Authors: Pelroy Gretchen A. , Eklund Melvin W.
Published: December 2020

The microfloral changes of irradiated petrale sole fillets during anaerobic (vacuum-packed in cans) refrigerated storage was determined by the identification of 1,260 microbial isolates to the generic level. The samples were irradiated at 0.0, 0.1, 0.2, 0.3, and 0.4 Mrad from a cobalt-60 gamma source, stored at 0.5 C, and examined periodically for spoilage and total microbial population and composition. The preirradiation flora consisted of
Achromobacter, Micrococcus, Pseudomonas
, coryneforms,
Lactobacillus
, and
Flavobacterium
. Immediately after irradiation,
Micrococcus, Achromobacter
, coryneforms, and
Bacillus
were predominant. After storage under vacuum, the spoilage flora of the nonirradiated petrale sole was predominantly
Pseudomonas
; the spoilage flora of the 0.1-Mrad irradiated samples consisted of
Pseudomonas
and
Lactobacillus
; and that of the 0.2-, 0.3-, and 0.4-Mrad samples was almost entirely
Lactobacillus
.
Examination of Feces from Food Handlers for Salmonellae, Shigellae, Enteropathogenic
Escherichia coli
, and
Clostridium perfringens
Authors: Hall Herbert E. , Hauser George H.
Published: December 2020

Duplicate fecal specimens from food handlers were collected in Louisiana. One set of specimens was examined immediately for salmonellae and shigellae by the Central Laboratory of the Louisiana State Board of Health in New Orleans; the other set was shipped to the Food Microbiology Unit at the Robert A. Taft Sanitary Engineering Center in Cincinnati, Ohio, where it was examined for enteropathogenic
Escherichia coli
(EEC) and
Clostridium perfringens
. A total of 219 specimens were examined by both laboratories. None yielded salmonellae or shigellae; 171 (78.1%) yielded
C. perfringens
; 175 (79.9%) yielded
E. coli
; and 14 (6.4%) yielded EEC. The 14 isolates of EEC were distributed among eight serotypes; one specimen yielded two serotypes. Multiple isolations of
C. perfringens
strains (two to four) were made from 64 (37.4%) of the specimens, and a total of 244 strains were isolated and studied for identifying characteristics. Of the total, only 87 (35.5%) could be identified serologically by a battery of 67 antisera; only 4 (1.6%) possessed the characteristics of the English “food-poisoning type.” The hemolytic activity on agar containing horse, ox, or sheep blood showed that 140 (57.1%) were “hemolytic,” 81 (33.1%) were “nonhemolytic,” and 23 (9.8%) gave varied results. Only 12 (4.9%) of the strains produced spores that resisted boiling for 30 min or more.
Intracellular Loss of Potassium in
Candida albicans
After Exposure to Polyene Antifungal Antibiotics
Authors: Zygmunt Walter A.
Published: December 2020

Eleven antifungal antibiotics, representing three broad macrolide classes, were studied in
Candida albicans
for their effect on growth and on the fate of intracellular K
+
. Marked differences were observed among these antibiotics between their growth-inhibitory activities and their adverse effects on the integrity of the cellular membrane as evidenced by loss of K
+
. Antibiotics most active in inhibiting growth of
C. albicans
were amphotericin B, trichomycin, candidin, candicidin (all heptaenes), and nystatin (a tetraene). In addition to those antibiotics, filipin and fungichromin also caused rapid leakage of K
+
from yeast cells. Interestingly, fungichromin was the least active of the 11 antibiotics in inhibiting growth. Concentrations of rimocidin 10 times as great as those required for growth inhibition caused only a slight loss in intracellular K
+
after 60 min.
Production of Enterotoxin A
Authors: Kato Eiichi , Khan Mahmood , Kujovich Lubinka , Bergdoll Merlin S.
Published: December 2020

A method for production of enterotoxin A in multiple liter lots is described. The medium contained 4% N-Z Amine NAK supplemented with 0.001% niacin and 0.00005% thiamine, and was adjusted to
p
H 6. The inoculated medium in lots of 400 to 600 ml, in 2-liter Erlenmeyer flasks, was incubated at 37 C for 24 hr on a gyrotory shaker at 280 rev/min. Production of 4 to 6 μg of enterotoxin A per ml occurred.
Oxidative Metabolism of Dermatophytes
Authors: McBride B. C. , Stock J. J.
Published: December 2020

A method for preparing young, actively respiring dermatophyte mycelia was obtained through the use of concentrated spore inocula and short growth periods in static culture. These hyphal elements were uniform in appearance, and vacuoles were absent. Concentrated mycelial suspensions were obtained which could be transferred easily and accurately. Glucose stimulated oxygen uptake in young mycelia which had been grown in a medium with low carbohydrate content. The level of endogenous respiration was affected by exogenous glucose only when this substrate stimulated oxygen uptake by less than 14%. Low nicotinamide adenine dinucleotide phosphate (NADP) dehydrogenase activity was noted in microconidia which have a low endogenous Q

o
2

value, whereas the activity of this enzyme was greater in macroconidia and mycelia which possess higher endogenous Q

o
2

values.
Microsporum gypseum
oxidizes 50% of exogenous glucose and assimilates the remainder. A large percentage of this substrate was assimilated into nitrogenous substances.
Anaerobic Production of
Thiobacillus denitrificans
for the Enzyme Rhodanese
Authors: Sargeant K. , Buck P. W. , Ford J. W. S. , Yeo R. G.
Published: December 2020

A method for the anaerobic growth of
Thiobacillus denitrificans
in a 140-liter (total capacity) stainless-steel culture vessel is described. As a result of controlling the
p
H value of cultures, and of ensuring that certain essential nutrients were in excess, cell yields approaching 700 mg (dry weight) per liter were obtained. These were over threefold higher than the best yields hitherto reported. The average rhodanese content of the cells from four cultures was 176,000 units per gram (dry weight). Adenosine-5′-phosphosulfate reductase (average content, 238 units per gram dry weight) and adenylate kinase (average content, 15,300 units per gram, dry weight) were also present.