bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of the Single-Dose Assay Technique to Psittacosis
Authors: Riley Jean M. , Campbell William E. , Orlando Michael D. , Shirey William N. , Dorsey Warren G.
Published: December 2020

When suspensions of psittacosis organisms were injected intracerebrally into groups of mice, a nearly linear relationship was observed between the concentration of the organisms injected and the mean time to death of the mice. Thirty-four psittacosis preparations were assayed and, by plotting the relationship between the reciprocal time to death for mice given the 10
-3
dilution of agent against the number of mouse intracerebral median lethal doses (MICLD
50
), a reference curve was established. By use of this reference curve, it was possible to estimate directly the LD
50
value of a psittacosis suspension of unknown concentration from the mean reciprocal time to death of a group of mice injected with a single dilution. By this procedure, the number of mice used was reduced by 62.5%, the titrations were completed in 3 to 5 days as compared with the usual 12 days, three to four times as many assays could be done in 1 day, and no assays had to be repeated. In addition, the precision of the single-dilution assay compared favorably with that of the LD
50
titration.
Heterokaryosis and Alkaloid Production in
Claviceps purpurea
Authors: Amici Alba M. , Scotti T. , Spalla C. , Tognoli L.
Published: December 2020

Strain 275 FI of
Claviceps purpurea
, which produces large amounts of peptide alkaloids in submerged culture, is a heterokaryon; after several generations on agar media, it segregates the single components. These components (by us labeled V, C, and W) are stable and produce almost no alkaloids under described conditions of submerged culture. The mycelium of strain 275 FI consists of hyphae with multinucleate cells and does not produce conidia. Strains V, C, and W form numerous anastomoses when grown together on agar. By combining strains V and C, a heterokaryon similar to 275 FI in appearance has been obtained. This new strain produces amounts of alkaloids much larger than those produced by V and C separately or in associated submerged culture. We conclude, therefore, that in strain 275 FI the heterokaryotic condition is favorable to the production of alkaloids. Several conidiaproducing cultures of
C. purpurea
of various origins, as well as sclerotia of the same species, have been examined. The results demonstrated that the heterokaryotic condition is rare in the cultures, but it is frequent in the mycelium from sclerotia. Since it is known that the production of alkaloids is typical of the sclerotial phase in
C. purpurea
, it is suggested that this capacity is related to the heterokaryosis of the producing strains.
Survey of the U.S. Gulf Coast for the Presence of
Clostridium botulinum
Authors: Ward B. Q. , Carroll B. J. , Garrett E. S. , Reese G. B.
Published: December 2020

In sediments and animals collected during warm weather months between Key West, Fla., and Brownsville, Tex.,
Clostridium botulinum
, predominantly type E, was demonstrable. Incidence was somewhat higher in the eastern Gulf animals, but the organism was present to the southernmost limits of both Texas and Florida. Types A and F were never detected in warm weather. No bottom type or any single species seemed exclusively vulnerable. In samples collected during colder weather, the east-west incidence differential was minimized in animals but not in sediments, overall incidence was lowered, all known types were present, and type E no longer predominated. Detection by fluorescent-antibody techniques was found to be inadequate.
Irradiation of Composts Used in the Propagation of
Agaricus bisporus
Authors: Splittstoesser D. F. , Massey L. M.
Published: December 2020

Unpasteurized horse manure composts were given radiation doses of 0.1 and 1.0 Mrad in an attempt to increase mushroom yields by eliminating competing microorganisms. Yields were enhanced by 0.1 Mrad but were lower than those obtained with heat-pasteurized composts. Composts subjected to 1.0 Mrad gave the lowest yields, probably because of the generation of ammonia and other toxic compounds. Only temporary changes in the predominant microflora could be detected as a result of ionizing radiations.
Statolon-induced Resistance of Mice to Mengovirus
Authors: Schmidt Jerome P. , Pindak Frank F.
Published: December 2020

Mice receiving statolon intraperitoneally were 1,000 times more resistant to intraperitoneal challenge with mengovirus than were untreated controls. Protection was afforded when statolon was administered 1 day before or 1 day after intraperitoneal inoculation with the virus. No therapeutic effect was observed when treatment with statolon was delayed for 2 days or more after virus infection. Exposure of mice to a simulated space cabin environment did not increase their susceptibility to the lethal effects of mengovirus infection or eliminate the protective effect of statolon.
Production of High-Titer Antibody in Serum and Ascitic Fluid of Hamsters for a Variety of Virus-induced Tumor Antigens
Authors: Gilden Raymond V. , Beddow Theodore G. , Huebner Robert J.
Published: December 2020

Methods not involving the use of viable tumors were developed for production of high-titer antibodies. The methods involved use of tumor homogenates. Homogenates from all tumor lines tested contained the characteristic tumor antigen. Attempts to isolate virus failed, and virus antigens could not be demonstrated. Immunization with tumor homogenates, in Freund's complete adjuvant, resulted in high antibody levels. None of the animals so immunized developed tumors.
Evaluation of Sellers Medium in Identification of Some Gram-negative Bacteria
Authors: Farkas-Himsley Hannah
Published: December 2020

The agar-slant medium of Sellers was evaluated as an identification aid in the differentiation between gram-negative bacilli of medical interest (
Enterobacteriaceae
excluded) and some of their saprophytic associates. With Sellers medium, a larger number of bacterial species and genera could be differentiated than with the oxidation-fermentation medium of Hugh and Leifson. Some species whose reclassification was recently suggested reacted on Sellers medium accordingly. Sellers medium (in a single tube) was found to be a distinct aid in the identification of a number of gram-negative bacteria which usually required several tests and an assortment of media.
Antifungal Activity of Isothiocyanates and Related Compounds
Authors: Drobnica Ľ. , Zemanová M. , Nemec P. , Kristián P. , Antoš K. , Hulka A.
Published: December 2020

Antifungal activity on
Aspergillus niger, Penicillium cyclopium
, and
Rhizopus oryzae
, as well as on additional saprophytic and parasitic fungi, was determined in 57 substituted derivatives of phenylisothiocyanate. Most of the investigated compounds displayed rather equal activity against the three mentioned fungi, in contradistinction to the analogues of natural benzyl- and β-phenylethylisothiocyanate with their characteristic low activity against
R. oryzae
. Differences occurred in the type of activity of compounds in which the —NCS group is directly bound on the aromatic moiety, as compared with those compounds in which this group is bound to the aliphatic radical or to the aromatic moiety indirectly by means of the methyl group or by a longer aliphatic chain. The results obtained confirm the negative influence of ionized substituents on the aromatic moiety, i.e., of —COOH, —CH
2
— COOH, and —SO
3
H groups, as well as of substituents which cause an extreme increase in reactivity of the —NCS group resulting in a high instability of the entire isothiocyanate molecule.
Distribution of Neuraminidase among Food-poisoning Strains of
Clostridium perfringens
Authors: Moss C. Wayne , Schekter Marcia A. , Cherry William B.
Published: December 2020

A survey was made to determine the distribution of the enzyme neuraminidase among 76 strains of
Clostridium perfringens
. Representative strains from each toxigenic type (A to F) and atypical
C. perfringens
type A food-poisoning strains of both American and English (Hobbs types) origin were tested. Both the American food-poisoning and nonfood-poisoning associated cultures consisted of both neuraminidase-positive and -negative strains. Furthermore, American strains which could not be differentiated from the original Hobbs cultures consisted of both neuraminidase-positive and -negative representatives. In contrast, the English (Hobbs) strains uniformly failed to produce an active intracellular or extracellular neuraminidase. No enzyme activity was detected in these strains when cultures were grown in different growth media, when grown in the presence of substrate (neuraminlactose), or upon extended incubation of enzyme preparations with substrate. With the exception of a type F strain, representative strains of the other toxigenic types (A to F) produced neuraminidase; 85% of the typical type A strains contained the enzyme.
Citrate Mannitol Agar Medium for Separating
Escherichia coli
Paracolons from
Shigella
Authors: Sellers Walter
Published: December 2020

A culture medium is described which not only differentiates
Shigella
from
Escherichia coli
but also serves as the basis for an extremely simple test which specifically identifies
E. coli
. A test that will identify an organism as
E. coli
is more useful than one that merely groups this species with other non-
Shigella
organisms. The theoretical basis for specificity of the test for
E. coli
and other uses for the medium are discussed.
Inhibition of B Virus in Cell Culture by 5-Iodo-2′-Deoxyuridine
Authors: Miller Francis A.
Published: December 2020

The antimetabolite 5-iodo 2′-deoxyuridine (IDU) interferes with B virus replication in monolayers of cynomolgous monkey kidney, KB and HEp 2 cells. To determine the effect of this clinically active nucleoside in laboratory antiviral screening systems, several methods were compared. Most of the methods used were capable of detecting the activity of IDU at low levels.
Use of Membrane Filter Technique in the Microbiological Control for the Brewing Industry
Authors: Nobile John
Published: December 2020

A physical method was developed involving serial filtration with membrane filters for separating yeast cells from bacteria. Such a method eliminates the need for antibiotics previously required to permit differential counting of such populations. All yeast cells filtered were successfully retained and cultivated on a 1.2-μ membrane filter by use of a synthetic medium. All bacteria filtered avoided entrapment on a 1.2-μ membrane filter and were successfully retained and cultivated on a 0.22-μ membrane filter with the same synthetic medium. Final filtrates from these serial filtrations were free from all yeast cells and bacteria when tested with Fluid Thioglycollate Medium.
Microbial Penicillinase in Soft Types of Cheese
Authors: Ledford R. A. , Deibel R. H.
Published: December 2020

Penicillinase activity was found in commercial samples of Limburger, Liederkranz, and Brick, as well as in Roquefort and Danish Blue cheeses. The numbers of penicillinase-producing bacteria in the cheese flora were estimated by use of the most probable numbers technique coupled with penicillinase determinations on the individual cultures. Although streptococci constituted the predominant flora in most of the samples, significant numbers of penicillinase-producing bacteria were also observed. Six of seven penicillinase-producing isolates that were studied in detail were micrococci; the other was an unidentified gram-positive, catalase-positive rod. The results suggest the widespread occurrence of penicillinase-forming micrococci on the surfaces of soft types of cheese.
Fate of Free Amino Acids and Nucleotides in Spoiling Beef
Authors: Jay James M. , Kontou Kalliopi S.
Published: December 2020

Fresh beef allowed to undergo microbial spoilage at 7 C showed decreases in quantity and types of amino acids as well as decreases in nucleotides when the initial number of bacteria per gram was high. When the initial number of bacteria was low, decreases were either not detectable or of low orders. It seems, therefore, that low-molecular-weight compounds of the above type support the growth of beef-spoilage bacteria rather than primary beef proteins. These low-molecular-weight compounds provide the probable sources of ammonia, hydrogen sulfide, and other such compounds associated with beef allowed to spoil at low temperatures.
Cephalexin, a New Orally Absorbed Cephalosporin Antibiotic
Authors: Wick Warren E.
Published: December 2020

A new antibiotic, structurally related to cephaloglycin, has been assigned the generic name cephalexin, 7-(D-α-amino-α-phenylacetamido)-3-methyl-3-cephem-5-carboxylic acid. In vitro antimicrobial activity of cephalexin does not equal that of cephaloglycin. However, excellent oral absorption and lack of serum binding of cephalexin compensates significantly for the lower in vitro activity. Exceptional efficacy against experimental bacterial infections in mice was obtained with cephalexin therapy as compared with cephaloglycin, tetracycline, and chloramphenicol. The data suggest that cephalexin merits clinical trial.
Agar-Gel Precipitin-Inhibition Technique for Histoplasmosis Antibody Determinations
Authors: Ray John G.
Published: December 2020

The agar-gel precipitin-inhibition technique has been modified to detect antibodies of
Histoplasma capsulatum
in sera from human clinical cases and experimental animals infected with this organism. By use of this modified technique, the histoplasmosis can be detected more consistently and reliably than with the direct agar-gel diffusion test, and titers are comparable to those attained by the complement-fixation serological technique.
Sporulation of
Clostridium perfringens
in a Modified Medium and Selected Foods
Authors: Kim Chung Hee , Cheney Roberta , Woodburn Margy
Published: December 2020

A modified sporulation medium for
Clostridium perfringens
was formulated in which a larger number of spores were produced than in SEC broth and in which spores of greater heat resistance were produced than in Ellner's medium when it was also used as the suspending medium. This modified medium consisted of 1.5% peptone; 3.0% Trypticase; 0.4% starch; 0.5% NaCl; and 0.02% MgSO
4
. The addition of 0.1% sodium thioglycolate and 0.0001% thiamine hydrochloride was optional. The optimal temperature for sporulation of five strains was 37 C in comparison with 5, 22, and 46 C. Sporulation had occurred by 6 hr and was essentially complete after 20 hr at 37 C. Noyes veal broth without glucose also supported the formation of heat-resistant spores but in smaller numbers than did the modified medium. Very low numbers of spores, or none, were produced under the same conditions in pea or tuna slurries.
Further Evaluation of Immunofluorescence Techniques for Detection of Shigellae in Fecal Specimens
Authors: Thomason Berenice M. , Nahmias André J. , Mathews Ann D.
Published: December 2020

The fluorescent antibody (FA) tests for group B and group D
Shigella
were reevaluated. Duplicate swab specimens from patients suspected of having shigellosis were cultured shortly after collection and after transport in a soft-agar holding medium. Smears for FA examination were made at the same time. Results obtained for the group D
Shigella
agree closely with those obtained in previous studies. The percentage of isolations of group B
Shigella
from transported specimens which were positive by FA was 59.6% as compared to 39.3 and 53.3% in previous studies.
S. flexneri
was isolated from 76.7% of the FA-positive specimens when they were examined shortly after collection. More isolates of
Shigella
were obtained when specimens were examined by both methods than when either method was used alone. The results indicated that FA tests for both group B and group D
Shigella
are practical and may be useful to laboratories engaged in
Shigella
isolation.
Electrical Sensing Zone Particle Analyzer for Measuring Germination of Fungal Spores in the Presence of Other Particles
Authors: Santoro T. , Stotzky G. , Rem L. T.
Published: December 2020

Microscopic, respirometric, and electronic sizing methods for measuring germination of fungal spores were compared. With the electronic sizing method, early stages of germination (i.e., spore swelling) were detected long before germ tube emergence or significant changes in respiratory rates were observed. This method, which is rapid, easy, sensitive, and reproducible, also permits measuring the germination of spores when similar-size particles are present in concentrations considerably in excess of the number of spores.
Inactivation of Microorganisms by Electrohydraulic Shock
Authors: Gilliland S. E. , Speck M. L.
Published: December 2020

The electrohydraulic shock treatment of microorganisms was accomplished by discharging high-voltage electricity (8 to 15 kv) across an electrode gap below the surface of aqueous suspensions of the microorganisms. This treatment was effective in destroying
Escherichia coli, Streptococcus faecalis
, vegetative cells and spores of
Bacillus subtilis
, and bacteriophage specific for
S. cremoris
ML1. The presence of added protein in bacterial suspensions resulted in reduced bactericidal action. Water subjected to electrohydraulic treatment retained a certain amount of toxicity when copper-core electrodes were used to apply the treatment. This was caused by copper liberated from the electrode during electrohydraulic discharge.
Mechanism of the Bactericidal Action Produced by Electrohydraulic Shock
Authors: Gilliland S. E. , Speck M. L.
Published: December 2020

Electrohydraulic shock was shown to produce oxidation reactions which inactivated certain compounds important in cellular metabolism. Enzymes that were inactivated included lactic dehydrogenase, trypsin, and proteinases of
Bacillus subtilis
. Free sulfhydryl groups and reduced nicotinamide adenine dinucleotide were oxidized. Adenosine triphosphate was destroyed, but deoxyribonucleic acid was not affected. Intracellular material of
Escherichia coli
lost its ability to absorb at 260 mμ after electrohydraulic shock. The bactericidal mechanism involved appeared to be due to nonselective oxidation reactions produced by high-voltage discharges in water. These oxidation reactions were probably mediated by free radicals produced in the water.
Examination of Market Foods for Coliform Organisms
Authors: Hall Herbert E. , Brown David F. , Lewis Keith H.
Published: December 2020

Food specimens (490) in nine categories were examined for total aerobic plate count and numbers and types of coliform organisms, including the enteropathogenic
Escherichia coli
(EEC). The total counts were compared with various suggested standards, and a limit of 100,000/g appeared to be a realistic goal, except for certain food types with a high level of natural flora. Plate counts in VRB were compared to counts obtained by isolation by enrichment in LST Broth, and the latter method produced a higher percentage of isolations. The presence of
E. coli
was determined by use of EC Medium incubated at 44.5 � 0.1 C. Only 40.4% of the positive EC tubes, however, contained
E. coli
. It appeared that a limit of 10 coliform organisms per g as a suggested standard could be met with several types of foods. Isolation of EEC was obtained only three times, or in 0.6% of the specimens.
New Combination of Antibiotics for Treatment of Contaminated Specimens for Viral Studies
Authors: Bourgeois Louis D. , Branche William C. , Ramey Felicienne H.
Published: December 2020

A study of a new combination of antibiotics (sodium oxacillin, colistin sulfate, and amphotericin B) has shown that 30 μg/ml of each in tissue culture maintenance medium can inhibit a group of the commonest bacterial and fungal contaminants while causing no observable cytopathology in rhesus monkey kidney, HeLa, or human amnion tissue cells. In addition, there was no inhibition of the titers of poliovirus, echovirus, coxsackievirus, and adenovirus in the three cell lines. Ten duplicate fecal samples, which remained contaminated with fungal or
Pseudomonas
organisms after treatment with penicillin and streptomycin, were treated with the new antibiotic combination. Contaminants were controlled in each, and a variety of viruses was recovered.
Use of a Methylene Blue Azide Medium for Isolation of Enterococci
Authors: Smith Rodney F. , Bodily Howard L.
Published: December 2020

A methylene blue azide medium (MBA), developed by Schaedler, Dubos, and Costello to isolate enterococci from the gastrointestinal tract of animals, was evaluated. This was done by comparing the isolation of enterococci from feces and saliva on the medium. Fifty-two catalase-negative, gram-positive cocci from human feces isolated from MBA were classified as enterococci. All strains grew in S F, 6.5% NaCl, and streptomycin broths, and all fermented mannitol. The isolates were provisionally subdivided into
Streptococcus faecalis
and
S. faecium
groups.
S. faecalis
-like strains fermented glycerol and pyruvate aerobically and produced acid in Snyder's medium (initial
p
H, 4.8). The
S. faecium
group fermented raffinose. Among all strains, several tests were variable. These included growth at 45 C, in 0.1% tellurite and in methylene blue milk. Three methods were employed to isolate and identify enterococci from the oral cavity. Direct streaking of MBA with saliva failed to produce any growth on the medium. Two other methods, with the use of various selective broths to promote the recovery of oral enterococci, failed to produce any bacteria capable of growing on MBA. The MBA-isolated fecal strains and oral viridans streptococci were generally indistinguishable on Mitis-Salivarius and K F agars. In experiments with fecal material, no gram-negative bacilli were found among the isolates selected. The MBA medium was judged as a high selectivity-low yield medium, and may provide a means of separating fecal and nonfecal enterococci.
New Antibacterial Agent (U-24,544) Isolated from
Streptomyces griseus
Authors: Herr Ross R. , Reusser Fritz
Published: December 2020

Antibiotic U-24,544 is a new agent isolated from the culture broth of a streptomycete strain. The antibiotic inhibits a variety of gram-positive and gram-negative bacteria in vitro, but is ineffective in treatment of experimental bacterial infections in mice. It is fairly cytotoxic in mammalian cell cultures and remarkably nontoxic in mice.
Differential Dialysis Culture for Separation and Concentration of a Macromolecular Product
Authors: Herold J. Downs , Schultz J. S. , Gerhardt Philipp
Published: December 2020

A differential dialysis flask, constructed with three chambers and two membranes of different porosity, was used to effect the separation and concentration of enterotoxin B produced extracellularly by a culture of
Staphylococcus aureus
. Variables were examined that affected the diffusion of glucose, as measured by half-equilibration time and permeability coefficient; the relative chamber volume, type of membrane, membrane masking, and mixing all exerted a substantial influence on diffusion rates. A number of membrane filters were tested for usefulness; one type, made with vinylidene fluoride, had desirable physical and diffusional properties, but neither it nor others consistently withheld the bacteria for more than a marginally useful period of about 50 hr. In ordinary two-chambered dialysis culture, the amount of enterotoxin reached 10 times that in control culture; in differential, three-chambered dialysis culture the comparable factor of increase was about 7, with about two-thirds of this amount being separated from cells in the product chamber of the flask.
Carbon Balance of a Mannitol Fermentation and the Biosynthetic Pathway
Authors: Lee Wei Hwa
Published: December 2020

The carbon balance was determined for a fermentation in which mannitol is produced from glucose by an
Aspergillus
species. The products found were: cells (17% of carbon input), CO
2
(26%), mannitol (35%), glycerol (10%), erythritol (2.5%), glycogen (1%), and unidentified compounds (8%). Thus, 92% of the carbon input was accounted for. Cell-free enzyme studies showed that mannitol was synthesized via the reduction of fructose-6-phosphate and not by the direct reduction of fructose. If the cell yield from glucose was assumed to be 50% and the theoretical conversion efficiency from glucose to polyols was 90%, as calculated from the energy balance, then 34% of the glucose carbon was used for growth and 53% was used for polyol formation.
Oxygen-Nitrogen Relationships in Autotrophic Nitrification
Authors: Wezernak C. T. , Gannon J. J.
Published: December 2020

Oxygen utilization by the autotrophic nitrifiers
Nitrosomonas
and
Nitrobacter
was studied. Experimental evidence is presented which reflects the effect of carbon dioxide fixation on overall oxygen utilization in autotrophic nitrification. Measurement of dissolved oxygen and inorganic nitrogen changes indicates that oxygen-nitrogen ratios in inorganic nitrogen oxidation are equal to 3.22 parts (expressed in milligrams per liter) of oxygen per part of ammonia nitrogen oxidized to nitrite nitrogen and 1.11 parts of oxygen per part of nitrite nitrogen oxidized to nitrate nitrogen. These values rather than the stoichiometric ratios should be used in nitrogenous oxygen demand calculations.
Treatment of Mengovirus Infection in Mice with Statolon
Authors: Pindak Frank F. , Schmidt Jerome P.
Published: December 2020

A single intraperitoneal injection of statolon was shown to exert a therapeutic effect on mice previously injected with the large plaque-forming variant of mengovirus. The
ld
50
and survival time data demonstrated that such treatment was effective when given 2 to 48 hr after infection. No protective effect was apparent when statolon was administered 3, 4, or 5 days after the viral challenge. It was concluded that statolon, or other similar interferon inducers, may be of therapeutic value in instances of accidental or other known exposure to hazardous viral agents.
Production of Rubella Hemagglutinating Antigen in Suspension Culture
Authors: Gitnick G. L. , Vincent M. M. , Auletta A. , Ley A. , Tzan N. , Sever J. L.
Published: December 2020

Rubella virus specific hemagglutinating antigen was prepared in the fluid phase of suspension cultures. Systems employing baby hamster kidney culture adapted inocula, nonadapted inocula, and cells derived from long-term infected suspension cultures were evaluated. Optimal specific hemagglutinating titers were obtained when kaolin-treated fetal bovine serum was used in the media and when the incoulum had previously been adapted in a suspension culture system. When cultures derived from long-term infected suspension systems were studied, the number of daily harvests in which acceptable titers were present was prolonged. However, titers were generally higher in suspension systems employing cells which had recently been infected.
Respiratory Activity of the Mycelium of
Eremothecium ashbyii
Authors: Fraile Elda R. , Zurita Victoria E.
Published: December 2020

The respiratory activity of the mycelium of
Eremothecium ashbyii
from submerged cultures was manometrically determined at different stages of its development and the results were statistically analyzed. The experiments were performed in a manner designed to diminish the endogenous respiration without affecting the response to the addition of an exogenous substrate. Lactose was the carbohydrate tested that produced the lowest oxygen consumption. The oxidation of maltose, which was high at 24 hr, decreased by more than 50% at 48 and 55 hr. Glucose and sucrose were actively oxidized by mycelium of three ages. From the intermediates of carbohydrate metabolism, 24-hr mycelium did not produce oxygen consumption with malate, lactate, citrate, fumarate, and α-ketoglutarate. At 48 hr, mycelium did not oxidize either lactate or citrate; 55-hr mycelium showed oxygen consumption with all intermediates tested. Acetate and pyruvate always produced high oxygen consumption. Ethyl alcohol produced high oxygen consumption with mycelium of all tested ages.
Mechanism of Thermal Injury in
Staphylococcus aureus
Authors: Allwood M. C. , Russell A. D.
Published: December 2020

The viability of and leakage from suspensions of
Staphylococcus aureus
stored in the temperature range 3 to 60 C were determined. There was a direct relationship, up to 50 C, between death and leakage, both of which increased with increasing temperature. At temperatures above 50 C, there was a different pattern of response, the total leakage being less at 60 C than at 50 C, although there was greater membrane damage at the higher temperature. Sucrose, 1
m
, almost completely prevented leakage at 37 and 50 C but not at 60 C.
Bacteriological Survey of the Frozen Prepared Foods Industry
Authors: Surkiewicz Bernard F. , Groomes Ralph J. , Padron Adriano P.
Published: December 2020

During sanitation-inspections of 29 potato-processing firms, 2,544 finished product units and 1,654 samples were collected and analyzed bacteriologically. The results of the bacteriological examination of finished French fries, fried potato cylinders, and dehydrated potatoes usually did not reveal the conditions of cleanliness under which they were produced. This was most likely due to the lethal effect of the terminal fry to which the French fries and potato cylinders are subjected, and because of the lethal effect of the dehydration temperatures used in processing the dehydrated potato products. However, as in most food-processing firms, line samples collected at each processing step reflect sanitary conditions and provide bacteriological support of inspectional evidence of plant insanitation. Most of the frozen stuffed baked potatoes examined were produced under poor sanitary conditions. But because this product is usually processed while hot, bacteriological examination of the finished product did not usually reveal the conditions of cleanliness under which they were produced. Again, inspectional observations were necessary for a full evaluation of the conditions of production. In contrast, frozen potato patties and frozen hash brown potatoes were more likely to reveal the conditions of sanitation under which they were produced as evidenced by the varying bacterial counts.
Use of Ultrasonic Energy in Assessing Microbial Contamination on Surfaces
Authors: Puleo John R. , Favero Martin S. , Petersen Norman J.
Published: December 2020

Ultrasonic tanks were evaluated for their ability to remove viable microorganisms from various surfaces for subsequent enumeration. Test surfaces were polished stainless steel, smooth glass, frosted glass, and electronic components. The position of contaminated surfaces in relation to the ultrasonic energy source, distance of the ultrasonic source from the test surfaces, and temperature of the rinse fluid were some of the factors which influenced recovery. Experimental systems included both naturally occurring microbial contamination and artificial contamination with spores of
Bacillus subtilis
var.
niger
. The results showed that ultrasonic energy was more reliable and efficient than mechanical agitation for recovering surface contaminants. Conditions which increased the number and percentage of microorganisms recovered by ultrasonic energy were: using a cold rinse fluid, placing the sample bottle on the bottom of the ultrasonic tank, and facing the contaminated surfaces toward the energy source. It was also demonstrated that ultrasonic energy could be effectively used for eluting microorganisms from cotton swabs.
Metabolism of 4-Chloro-2-Methylphenoxyacetic Acid by Soil Bacteria
Authors: Bollag J.-M. , Helling C. S. , Alexander M.
Published: December 2020

A microorganism capable of degrading 4-chloro-2-methylphenoxyacetic acid (MCPA) was isolated from soil and identified as
Flavobacterium peregrinum
. All of the chlorine of MCPA was released as chloride, and the carboxyl-carbon was converted to volatile products by growing cultures of the bacterium, but a phenol accumulated in the medium. The phenol was identified as 4-chloro-2-methylphenol on the basis of its gas chromatographic and infrared characteristics. Extracts of cells of
F. peregrinum
and of a phenoxyacetate-metabolizing
Arthrobacter
sp. dehalogenated MCPA and several catechols but not 4-chloro-2-methylanisole. The
Arthrobacter
sp. cell extract was fractionated, and an enzyme preparation was obtained which catalyzed the conversion of MCPA to 4-chloro-2-methylphenol. The latter compound was not metabolized unless reduced nicotinamide adenine dinucleotide phosphate was added to the fractionated extract. The phenol in turn was apparently oxidized to a catechol by components of the enzyme preparation.
Quantitative Analyses of Certain Enteric Bacteria and Bacterial Extracts
Authors: Glenn William G. , Ralston James R. , Russell Warren J.
Published: December 2020

Standardized individual preparations of five population levels of eight enteric organisms [
Escherichia coli
(O4:H3),
E. coli
(O111:B4:H12),
Salmonella enteritidis, S. paratyphi
B,
S. typhimurium, Shigella boydii, S. dysenteriae
, and
S. sonnei
) were prepared. Dry weights, calculated mean cell weight, and nitrogen content of bacterial suspensions before, and of supernatant fluids after, ultrasonic disruption are tabulated. Percentages of disruption, estimated from nitrogen concentration ratios of the suspensions and supernatant fluids, are given. These data are presented as guidelines for the preparation of bacterial extracts prior to precipitin analyses.
Photodynamic Inactivation of Newcastle Disease Virus with Acridine Orange
Authors: Frank G. H. , Foster J. W.
Published: December 2020

Newcastle disease virus in allantoamnionic fluid was photosensitized with acridine orange, and then photodynamically inactivated. The inactivation rate was directly proportional to light intensity and to dye concentrations up to a level of approximately 100 to 200 μg/ml. Inactivation occurred at approximately an exponential rate for the first 4.5 log
10
units of virus, and then continued at a decreasing rate.
Salmonellae Associated with Further-processed Turkey Products
Authors: Bryan Frank L. , Ayres John C. , Kraft Allen A.
Published: December 2020

“Further-processed” turkey products, prepared from chilled, eviscerated, and thawed carcasses at two commercial turkey-processing plants, were evaluated, for the presence of salmonellae. These organisms were isolated from swab samples from 12% of chilled, eviscerated turkey carcasses, 27% of finished products, and 24% of processing equipment. The same serotypes as those found throughout a plant on any one visit were recovered from 31% of rinse-samples taken from hands and gloves of processing personnel. Salmonellae were found in samples taken on 37 of 48 visits; a greater number of recoveries were made on days when freshly killed turkeys were processed (87%) than when frozen-defrosted carcasses were processed (59%). The predominant serotype isolated from meat and environment usually changed from visit to visit.
Salmonella sandiego
and
Salmonella anatum
were the most frequent among 23 serotypes recovered. Most of the isolated serotypes are commonly associated with turkeys and have been incriminated as causative agents of human salmonellosis. The implication is that further-processed turkey products, if inadequately cooked by the consumer and if improperly refrigerated between the time of manufacture and consumption, could directly transmit salmonellae. These same products might also contaminate other foods by introducing salmonellae into food-preparation areas.
Monitored Environment System to Control Cell Growth, Morphology, and Metabolic Rate in Fungi by Oxidation-Reduction Potentials
Authors: Rippon John W.
Published: December 2020

A device for the adjustment, maintenance, and monitoring of a desired oxidation-reduction potential in a liquid environment is described. The filamentous species,
Penicillium lilacinum
and
Trichophyton schoenleinii
, and the dimorphic species,
Histoplasma capsulatum
, developed budding yeastlike cells when grown in a liquid medium with a low oxidation-reduction potential. When the organisms were inoculated into fresh medium, they returned to the filamentous condition as the oxidation-reduction potential was restored to a more positive (oxidizing) environment.
Proteolytic Activity of Microorganisms Isolated from Freshwater Fish
Authors: Kazanas Nuria
Published: December 2020

A raw fish-juice was prepared and sterilized through the use of
60
Co γ-irradiation. It was evaluated for suitability in an agar medium for testing the proteolytic activity of bacteria isolated from fish. Microorganism proteolytic activity was also detected by conventional methods with skim milk-agar. We tested 1,145 isolates from fresh and spoiling irradiated (0.0, 0.3, and 0.6 Mrad) yellow perch fillets for proteolytic activity, by the use of both media. Most isolates that showed proteolytic activity exhibited this activity in both media. A few isolates showed proteolytic activity only in one medium or the other. Proteolysis was found mainly among bacteria isolated from nonirradiated perch fillets. Nonproteolytic organisms were slightly more abundant than were proteolytic ones throughout refrigerated storage (6 days); the latter constituted 48% of the total organisms. Irradiation eliminated essentially all proteolytic bacteria when the fillets were stored at 1 C. However, some proteolytic bacteria survived for a few days after irradiation when the fillets were stored at 5 C.
Chromatographic Separation of the Pigment Fractions from a
Serratia marcescens
Strain
Authors: Lynch D. L. , Worthy T. E. , Kresheck G. C.
Published: December 2020

A procedure was developed for the separation of pigment fractions in a wild-type
Serratia marcescens
strain. Separation was achieved by column chromatography and elution with several organic solvents. At least six pigment fractions were obtained from the alumina columns by this technique, whereas only four fractions had been reported previously. Spectral and elemental analyses indicate that, in
S. marcescens
, prodigiosin is a complex of six fractions, differing in absorption spectra while retaining the general characteristics of the whole pigment.
Survival and Outgrowth of
Clostridium botulinum
Type E Spores in Smoked Fish
Authors: Christiansen Lee N. , Deffner Janet , Foster E. M. , Sugiyama H.
Published: December 2020

Chub injected in the loin muscle with 10
6
Clostridium botulinum
type E spores were smoked to an internal temperature of 180 F (82.2 C) for 30 min, sealed in plastic bags, and incubated at room temperature (20 to 25 C) for 7 days. Viable type E spores were found in practically all such fish. Toxin formation by the survivors in the smoked fish was dependent on the brine concentration of the smoked fish. A brine concentration of 3% or higher, as measured in the loin muscle, inhibited toxin formation. Six different type E strains gave similar results. Only a few hundred of the million spores in the inoculum survived the smoking. Moisture in the atmosphere during smoking did not reduce the incidence of fish with type E survivors.
Aerosols of Mycoplasmas, L Forms, and Bacteria: Comparison of Particle Size, Viability, and Lethality of Ultraviolet Radiation
Authors: Kundsin Ruth B.
Published: December 2020

Aerosols of microorganisms were tested for particle size by use of an Andersen sampler. Mycoplasma aerosols had an average count median diameter (CMD) of 2.1 ± 0.5 μ.
Staphylococcus aureus
L forms gave an average CMD of 4.6 ± 1.7 μ; the diphtheroid L form, a CMD of 3.4 ± 0.3 μ.
Escherichia coli
had a CMD of 5.4 ± 2.5 μ;
Neisseria sicca
, 3.3 ± 0.5 μ;
N. meningitidis
, 3.4 ± 0.2 μ.
S. aureus
ATCC 6538, the parent strain of the L form, yielded a CMD of 3.9 ± 1.2 μ.
Candida albicans
gave an average CMD of 5.9 ± 1.4 μ. All organisms tested survived aerosolizing and could be recovered in viable form for at least 1 hr. Ultraviolet radiation at 2,537 A destroyed the bacteria and mycoplasmas instantaneously, and destroyed 87% of the L forms of
S. aureus
, 69% of the diphtheroid L form, and 98% of the
C. albicans
cells. After irradiation, viable particles of the L form and
C. albicans
aerosols were consistently larger, indicating that clumping led to survival. Submicron size particles were found in aerosols of all species tested except
C. albicans
.
Bacteriological Survey of the Frozen Prepared Foods Industry
Authors: Surkiewicz Bernard F. , Groomes Ralph J. , Shelton L. Robert
Published: December 2020

During sanitation-inspections of 23 breaded-fish processors, 573 finished product units and 604 line samples were collected and analyzed bacteriologically. Data for finished product units processed on the same data are presented in groups; most of the groups consisted of 10 units. Groups of frozen, raw-breaded fish produced under good and poor conditions of sanitation were studied. No more than 20% of the units in each group produced under good conditions of sanitation were positive for
Escherichia coli
or coagulase-positive staphylococci. Groups of frozen, fried-breaded fish produced under good and poor sanitary conditions were also studied. No more than 10% of the units in each good-sanitation group were positive for
E. coli
or coagulase-positive staphylococci. However, approximately 30% of the groups processed under poor sanitary conditions also did not exceed these viable bacterial counts because of the lethal effect of the terminal fry to which the product is subjected. It was found that line samples collected from the processing lines reflected the sanitary conditions of the plant and provided bacteriological support for inspectional evidence of plant insanitation.
Detection of Botulinal Toxins by Immunodiffusion
Authors: Vermilyea Barry L. , Walker Homer W. , Ayres John C.
Published: December 2020

A procedure employing concentration with Sephadex and analysis by gel diffusion (Ouchterlony) was used to detect the toxins of
Clostridium botulinum
in foods. Botulinal toxins with toxic levels of 370 to 557 mouse LD
50
per milliliter were detected in the food samples. Test results were verified by use of the mouse protection test. Approximately 24 hr were required to complete the entire procedure.
Spoilage Bacteria in Canned Foods
Authors: Lin Chau-Ching , Wu Bih-Keng , Lin Dar-Kuan
Published: December 2020

Bacillus stearothermophilus
was found to be a cause of spoilage of asparagus canned in Taiwan. The
F
250
and
Z
values of the isolates were 14.2 min and 17.8 F (-7.9 C), respectively.
Activated-Sludge Nitrification in the Presence of Linear and Branched-Chain Alkyl Benzene Sulfonates
Authors: Baillod Charles R. , Boyle W. C.
Published: December 2020

The effects of biodegradable linear alkyl benzene sulfonate and branched-chain alkyl benzene sulfonate detergents on activated-sludge nitrification were investigated by administering a synthetic waste containing up to 23 mg of each detergent per liter to eight bench-scale, batch, activated-sludge units. It was found that both detergents tended to promote complete oxidation of ammonia to nitrate, whereas control units produced approximately equal amounts of nitrite and nitrate. Various hypotheses are offered to explain the phenomenon.
Direct Method for Determining the Viability of a Freshly Generated Mixed Bacterial Aerosol
Authors: Green Louis H. , Green Gareth M.
Published: December 2020

A direct method was developed to determine the viability of a freshly generated mixed bacterial aerosol. A mixed suspension of
32
P-labeled
Staphylococcus aureus
and
35
S-labeled
Proteus mirabilis
was nebulized, and the aerosol was collected and separated according to particle size with an Andersen sampler. Quantitative and qualitative bacteriological and radioisotopic techniques were used to obtain ratios of bacterial to radioactive counts for each organism in samples of the nebulizer suspension and aerosol. Loss of viability was calculated from the change that occurred between the ratio of the nebulizer suspension and the ratio of the aerosol. The viability of
S. aureus
was unaffected by aerosolization, whereas the viability of
P. mirabilis
declined by 20 to 60% and was inversely proportional to particle size. The advantages of this method over present indirect methods, as well as potential applications of the method, are discussed.
Characteristics of
Cytophaga psychrophila
(Borg) Isolated from Outbreaks of Bacterial Cold-Water Disease
Authors: Pacha R. E.
Published: December 2020

Characteristics of 10 strains of
Cytophaga psychrophila
isolated during a number of epizootics of bacterial cold-water disease were compared. Morphological, cultural, biochemical, and serological data showed that the organisms were very closely related. The isolates exhibited gliding motility, formed neither fruiting bodies nor microcysts, were actively proteolytic, and grew only at low temperatures. Data presented extend the description of
C. psychrophila
.
Plaque Formation by 55 Rhinovirus Serotypes
Authors: Fiala Milan
Published: December 2020

Plaque production by 55 rhinoviruses in several lines of HeLa cells is reported. Forty-nine types produced macroscopic plaques under the conditions described previously employing 30 mM MgCl
2
and 30 μg/ml of DEAE-dextran in overlay and M HeLa cells. Basically three kinds of plaques were observed: clear large and intermediate sized plaques and small turbid plaques. Five rhinoviruses produced plaques only in a sensitive clonal line isolated from the M HeLa line. Rhinovirus type 4 produced plaques after the pretreatment of cells with actinomycin D. Enhancement of plaque formation by MgCl
2
has been demonstrated to date with 17 rhinoviruses. Some rhinoviruses were enhanced either by DEAE-dextran or by dextran sulfate in the overlay. No inhibitors were found in any of 10 bovine sera tested. Rhinovirus type 2 was visualized inside HeLa cells by electron microscopy and there appeared to be a very high ratio of physical particles per infectious unit of virus.
Mortality of Altitude-exposed Mice Infected with
Pasturella tularensis
Authors: Ball Robert J. , Schmidt Jerome P.
Published: December 2020

The influence of reduced barometric pressure equivalent to an altitude of 18,000 ft (5,486 m) on the susceptibility of mice to tularemia was investigated by exposing groups of animals to the test environment before, after, or before and after intraperitoneal inoculation of 225 colony-forming units of
Pasteurella tularensis
. Similarly infected control animals were not exposed to the experimental environment. Two measurements of mortality were employed: (i) the day on which 50% of the mice were dead; and (ii) the number of dead mice on the 8th day. Continuous altitude exposure for 14 days prior to infection had no effect on host susceptibility but exposure after infection significantly increased mortality (
P
< 0.001).
Activity of Homocarnosine and Other Compounds Against Staphylococcal Infections in Mice
Authors: Tanaka Kinji , Tsuchiya Yoshiki , Berberich Norbert J. , Mukkada Antony J. , Nutini Leo G. , Cook Elton S.
Published: December 2020

Homocarnosine and carnosine have been identified in bovine brain extracts which are effective in protecting mice against infections by
Staphylococcus aureus
. These peptides, as well as
l
-1-methylhistidine, β-alanine, γ-aminobutyric acid, δ-aminovaleric acid, ε-aminocaproic acid, 1-aminomethylcyclohexane-4-carboxylic acid, and anserine, were tested as prophylactic agents against
S. aureus
infections in C3H and Swiss mice. Histidine and methylhistidine were ineffective in preventing mortality in both mouse strains. Carnosine, anserine, and ε-aminocaproic acid were effective in C3H but not in Swiss mice. β-Alanine and γ-aminobutyric acid were weakly effective (C3H) or ineffective (Swiss). δ-Aminovaleric and 1-aminomethylcyclohexane-4-carboxylic acid (tested only in Swiss) were somewhat effective in early stages of the infection. Homocarnosine was the best compound and was highly effective in protecting both mouse strains against
S. aureus
infections by the testing procedure employed.