bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth of Chikungunya Virus in Baby Hamster Kidney Cell (BHK-21-Clone 13) Suspension Cultures
Authors: Davis Jack L. , Hodge Howard M. , Campbell William E.
Published: December 2020

This report describes the methods used to obtain high titers of chikungunya virus with suspension cultures of BHK-21-clone 13 cells. The cells were grown at 37 C to a cell concentration of 10
6
to 2 × 10
6
per ml. After maximum cell growth, the cells were inoculated with chikungunya virus at a multiplicity of 1 to 2 50% suckling mouse intracerebral lethal doses (SMICLD
50
) per cell in the spent Eagle's minimum essential medium for suspension cultures (MEMS), or the cell cultures were centrifuged at 200 ×
g
and resuspended in either fresh MEMS or medium 199 prior to inoculation. The medium used had no effect on virus titer. The inoculated cultures were incubated at 34 C until the cell viability dropped to 30%, which usually occurred 28 to 30 hr postinoculation. After these procedures, chikungunya virus titers of log
10
10.3 to 11.8 SMICLD
50
per ml were obtained.
Biological Characteristics of Cloned Populations of Herpes Simplex Virus Types 1 and 2
Authors: Smith Jerry W. , Rodriguez José E. , McKee Albert P.
Published: December 2020

By using cloned types 1 and 2 herpes simplex virus, obtained by selecting large and small plaques produced by material from human lesions, studies were performed to compare properties between preparations of each type. Regarding the rate of inactivation by ultraviolet light, no differences were found between the two antigenic types and none between the preparations obtained from either type. In contrast, type 1 preparations were found to be more readily inactivated at 45 C than type 2. Plaque size of cloned preparations changed by passage in cell culture. A broader range of plaque sizes was obtained, and average plaque size was larger. After 20 passages, preparations obtained from different types gave rise to one of three kinds of cytopathic effect. The cytopathic effect produced by type 1 preparations remained as before 20 passages and consisted of round cells in a compact central mass. For type 2, two kinds of cytopathic effect were seen in cloned preparations. This consisted of aggregates of round cells (seen in preparations before 20 passages) or of large, loose aggregates of round cells of various sizes. Results from neutralization studies using virus before and after 20 passages in cell culture versus antisera prepared against live or ultraviolet-inactivated virus showed no differences between cloned preparations obtained from a given type.
Effect of Fatty Acid Derivatives on Rumen Methane and Propionate In Vitro
Authors: Van Nevel C. J. , Demeyer D. I. , Henderickx H. K.
Published: December 2020

The effect of several fatty acid derivatives on methane and propionate in the rumen is described. A possible explanation for the observed inverse relationship between methane and propionate is given.
Pneumatic, Multiple, Simultaneous Inoculator for Plastic Trays
Authors: Zussman Ronald A.
Published: December 2020

A device is described which consists of a bonded Plexiglas-silicone rubber plate, perforated to hold capillary pipettes in register with the wells of a plastic tray to be inoculated. Pipette contents are simultaneously discharged by positive air pressure, initiated by closing an exhaust port with the thumb.
Cephaloglycin and Its Biologically Active Metabolite Desacetylcephaloglycin
Authors: Wick W. E. , Wright W. E. , Kuder H. V.
Published: December 2020

Chromatographic studies and microbiological assays show that, after oral administration, cephaloglycin is partially converted in man to a biologically active metabolite desacetylcephaloglycin. The antibacterial activity of this metabolite compared to that of cephaloglycin is equivalent against gram-positive organisms but is lower against gram-negative bacilli. Successful therapy of urinary tract infections with cephaloglycin must be mainly attributed to the antibacterial activity of this metabolite. At the present time, it is not possible to assess what influence low amounts of unaltered cephaloglycin have on the outcome of therapy.
Effect of Water Activity on Enterotoxin B Production and Growth of
Staphylococcus aureus
Authors: Troller John A.
Published: December 2020

Staphylococcus aureus
C-243, an enterotoxin B-producing strain, was cultured on media adjusted to various water activity (a
w
) levels by means of two different solute systems. Total numbers and rate of growth were diminished at low a
w
levels, and enterotoxin synthesis was extremely sensitive to reduction in a
w
. A reduction of a
w
from 0.99 to 0.98 in one medium and from 0.99 to 0.97 in the other medium resulted in extremely low levels of enterotoxin in spent culture media despite the attainment of high numbers of staphylococci.
Incorporation of Radioactive Seleno-(
75
Se)-Methionine into Mumps Virus
Authors: Jensik Stephen C. , Northrop Robert L.
Published: December 2020

Mumps virus was grown in embryonated chicken eggs in the presence of radioactive seleno-(
75
Se)-methionine. Virus in the allantoic and amniotic fluids was concentrated in a sucrose density gradient, and a peak of viral material coincided with a significant peak of
75
Se-radioactivity. The radioactivity was acid-insoluble and remained associated with the virus after purification by erythrocyte adsorption and elution and centrifugation on a second sucrose density gradient. After amino-acid hydrolysis of the radioactive virus, only
75
Se-methionine was recovered by chromatographic analysis. These results demonstrate that the radioactive
75
Se-methionine was incorporated into protein of infectious mumps virus.
Isolation and Identification of Psychrophilic Species of
Bacillus
from Milk
Authors: Shehata T. E. , Collins E. B.
Published: December 2020

Forty isolates from 97 raw milk samples (heated to 80 C for 10 min and stored at 4 to 7 C for 3 to 4 weeks) were sporeforming, aerobic, gram-positive or gram-variable, rod-shaped bacteria. Fifteen isolates that were identified had characteristics similar to species of
Bacillus
, except that they had lower growth temperature ranges, were gram-variable, and were somewhat different in sugar fermentations. Four isolates grew well within 2 weeks at 0 C, but they grew faster at 20 to 25 C. These psychrophilic sporeforming bacteria, the importance of which is discussed, are considered to be variant strains of mesophilic bacilli adapted to low temperatures.
Aerosol Survival of
Pasteurella tularensis
Disseminated from the Wet and Dry States
Authors: Cox C. S.
Published: December 2020

The aerosol survival in air and in nitrogen was measured for
Pasteurella tularensis
live vaccine strain, disseminated from the wet and dry states. The results showed that most of the loss of viability occurred in less than 2 min of aerosol age, i.e., a rapid initial decay followed by a much slower secondary decay. In nitrogen and air, minimum survival occurred at 50 to 55% relative humidity (RH) for wet dissemination and at 75% RH for dry dissemination. This shift indicated that aerosols produced by wet and dry dissemination were not equivalent and suggested that survival might not be related to bacterial water activity or content. The results showed that rehydration is the key process with regard to survival, but that lysis on rehydration is not a primary death mechanism. The effects of oxygen were complex because it could be either protective or toxic, depending upon other conditions. The protective action of oxygen was through an effect on the spent culture suspending fluid. The latter contained a toxic component, the activity of which is suppressed by oxygen; possibly the component is pumped away during freeze-drying. A toxic effect of oxygen was not found in the presence of spent culture media because the toxicity of the latter masks such an effect. With other bacterial suspending fluids, oxygen was shown to be toxic at low RH. Similar effects with regard to oxygen toxicity were also found with a laboratory strain of
P. tularensis
. Differences in oxygen toxicity for aerosols generated from the wet and dry states also suggest that bacterial water content and activity do not control aerosol survival.
Incidence of Infectious Drug Resistance Among Fecal Coliforms Isolated from Raw Sewage
Authors: Sturtevant Alton B. , Cassell Gail H. , Feary Thomas W.
Published: December 2020

Raw sewage was examined for the incidence of antibiotic-resistant coliforms present among both total and fecal coliforms. In both groups, it was found that approximately 3% of the coliform bacteria were resistant to two or more antibiotics. Of these organisms, 48% were capable of transferring all or part of their antibiotic resistance to an antibiotic-sensitive, F
−
, derivative of
Escherichia coli
K-12. Among the R factors identified, those conferring resistance to streptomycin-tetracycline, ampicillin-streptomycin-tetracycline, and ampicillin or ampicillin-streptomycin accounted for 23, 20, and 15%, respectively, of the total R factors detected. The data indicate a significant level of infectious drug resistance among the fecal coliforms of the urban population. The data indicate further that because of the high incidence of coliform bacteria found to be doubly resistant to streptomycin and tetracyline, the inclusion of these antibiotics in selective media used for routine total or fecal coliform counts may serve to identify domestic sources of pollution.
Use of Horseradish Peroxidase-Labeled Antibody for Light and Electron Microscope Localization of Reovirus Antigen
Authors: Ubertini Tito , Wilkie Bruce N. , Noronha Fernando
Published: December 2020

Horseradish peroxidase-labeled antibody was used for light and electron microscopic localization of reovirus antigen in tissue culture. Reaction product in infected cells was easily detected in the cytoplasm, and the procedure was as sensitive as the fluorescent-antibody technique. At the electron microscopic level, infected and enzyme-labeled antibody-treated cells showed accumulations of reaction product at the sites of viral replication and around the viral particles. Reaction product was not detected in unstained infected cells, in stained uninfected cells, or in cells infected with an unrelated virus.
Pigment Formation for Differentiating
Cryptococcus neoformans
from
Candida albicans
Authors: Korth H. , Pulverer G.
Published: December 2020

When 2,3- or 3,4-dihydroxybenzoic acid, 3,4-dihydroxyphenylalanine, and 3,4-dihydroxycinnamic acid are added to growth media, they are converted to a characteristic brown pigment by
Cryptococcus neoformans.
This pigment formation has hitherto been encountered only when this microorganism was cultivated on media containing
Guizotia abyssinica
seed. This phenomenon can be used for differentiating
Cryptococcus neoformans
from
Candida albicans.
Possible precursors of these
o
-diphenols (quinic acid, aromatic monohydroxy acids, or tyrosine) do not give rise to the brown pigmentation.
Simple Micromethod for Detecting Antifungal Activity
Authors: Pero Ronald W. , Owens Robert G.
Published: December 2020

A bioassay that can be carried out on thin-layer chromatograms is described for rapid detection of antifungal or general cytotoxic activity with microquantities of test compound.
In Vitro Susceptibility of
Corynebacterium diphtheriae
to Thirteen Antibiotics
Authors: Gordon Ralph C. , Yow Martha D. , Clark Dorothy J. , Stephenson Winnie B.
Published: December 2020

Fourteen isolates of
Corynebacterium diphtheriae
proved to be most susceptible to erythromycin and rifampin and were also inhibited by 11 other antibiotics tested.
Apparatus for Metabolic Studies with Anaerobes
Authors: Lev M. , Milford A. F.
Published: December 2020

An apparatus is described which allows metabolic experiments with obligate anaerobic bacteria to be performed with minimal disturbance of the
E
h
of the culture.
Removal of Nonidet P40 Absorbance for Optical Density Monitoring of Cytoplasmic Ribonucleic Acid
Authors: Schluederberg Ann
Published: December 2020

Absorbance at 260 nm due to Nonidet P40 in cytoplasmic extracts can effectively be reduced by extraction with CHCl
3
without appreciable loss of ribonucleic acid.
Capillary Tube Assay for Staphylococcal Enterotoxins A, B, and C
Authors: Fung Daniel Y. C. , Wagner Janet
Published: December 2020

A miniaturized single-gel diffusion procedure for detection of staphylococcal enterotoxin is proposed. The technique effects substantial savings of reagents and is easy to perform.
Metachromatic Agar-Diffusion Methods for Detecting Staphylococcal Nuclease Activity
Authors: Lachica R. V. F. , Genigeorgis C. , Hoeprich P. D.
Published: December 2020

Based on the metachromatic property of Toluidine Blue O, three, convenient agar-diffusion methods have been developed that enable detection of the nuclease of
Staphylococcus aureus
at concentrations as low as 0.005 μg/ml in agar and broth cultures. The interactions of agar and deoxyribonucleic acid with Toluidine Blue O are discussed.
Fatty Acids of
Mycobacterium kansasii
Authors: Thoen Charles O. , Karlson Alfred G. , Ellefson Ralph D.
Published: December 2020

The cellular fatty acids of 35 strains of
Mycobacterium kansasii
isolated from clinical material were analyzed to establish properties by which we could identify and characterize these acid-fast microorganisms. The fatty acids were extracted from cells grown in liquid synthetic media, and they were analyzed as methyl esters by gas-liquid chromatography. The fatty acid profiles of all strains were similar. They differed from fatty acid profiles of other mycobacteria by their content of a saturated fatty acid with a methyl group at C2.
Inhibition of the Plaquing Efficiency of T4r
+
Bacteriophage by Subtilisin
Authors: Ferris James J. , Clesceri Lenore S.
Published: December 2020

The mechanism by which the replicative cycle of T4r
+
phage is inhibited by certain nonhost bacterial systems was investigated. Some
Bacillaceae
, especially
Bacillus subtilis
, decreased the plaquing efficiency of this virus more than 95% within 24 hr of exposure.
Sarcina lutea
and
Micrococcus
sp. both failed to cause any significant change in the infectivity of T4r
+
phage. Preliminary investigations into the nature of the inhibitory substance(s) suggested that an extracellularly elicited protein was at least partially responsible for this effect. Further analysis has implicated subtilisin, an exoprotease from
B. subtilis
, as the cause of some, if not all, of the observed decrease in plaquing efficiency. Gel-filtration chromatography of control and treated
14
C-labeled T4r
+
phage showed a wide dispersal of phage-specific material of these particles after 24 hr of exposure to pure subtilisin or to expended medium exoprotease from
B. subtilis.
It was concluded that
B. subtilis
exoprotease is capable of chemically altering the structure of the phage capsid, thus causing a decrease in its plaquing efficiency.
Production of Extracellular Polysaccharide Matrix by
Zoogloea ramigera
Authors: Parsons Alice B. , Dugan Patrick R.
Published: December 2020

Zoogloea ramigera
115 synthesized large amounts of matrix polymer from fructose, galactose, glucose, lactose, mannose, soluble starch, and sucrose when these carbohydrates were used as supplements to a chemically defined medium. All of them supported polymer synthesis to the extent that cultures thickened to a gel. Concentration of carbohydrate nutrients in the range 0.5 to 2.0% was not a critical factor in determining eventual total thickening to a gel, except in relation to the incubation time required. Glucose disappeared from the growth medium rapidly and correlated with increasing cell growth and poly-β-hydroxybutyrate (PHB) accumulation. PHB concentration decreased as extracellular polymer was synthesized, suggesting a link between PHB and extracellular polymer production.
Effect of Relative Humidity on Dynamic Aerosols of Adenovirus 12
Authors: Davis Gary W. , Griesemer Richard A. , Shadduck John A. , Farrell Robert L.
Published: December 2020

Dynamic aerosols of adenovirus 12 were generated in the same Henderson apparatus under conditions of high, medium, and low relative humidity. High relative humidities resulted in more recovery of adenovirus 12 from aerosols and lungs of newborn Syrian hamsters. At 89, 51, and 32% relative humidity, the total infectious virus recovered from a 20-min aerosol was 10
6.7
, 10
6.0
, and 10
4.3
TCD
50
, respectively. Hamsters exposed to these 20-min aerosols retained measured lung doses of 10
3.0
, 10
2.4
, and 10
1.0
TCD
50
, respectively. The measured retained lung doses were compared to calculated inhaled lung doses based on both total virus aerosolized and total virus recovery from the aerosols.
Method for Typing Antisera to
Herpesvirus hominis
by Indirect Hemagglutination Inhibition
Authors: Bernstein Michael T. , Stewart John A.
Published: December 2020

A test for typing antisera to
Herpesvirus hominis
that uses the method of indirect hemagglutination inhibition is described. The test, which is based upon the differential absorption of herpes antisera by preparations of type 1 and type 2 antigens, is rapidly and easily performed. The results permit some conclusions to be drawn regarding the antigenic relationships between the two virus types. Some of the practical limitations of the test are discussed.
Determination of Drug Resistance of
Mycobacterium tuberculosis
Cultures
Authors: Montalbine V. , Collins F. M.
Published: December 2020

A total of 3,303 strains of
Mycobacterium tuberculosis
were tested for sensitivity to streptomycin (SM), isoniazid (INH), and
p
-aminosalicylic acid (PAS) by the Steenken modified minimal inhibitory concentration (MIC) test. A simultaneous double blind comparison was carried out on 277 selected strains by the Steenken MIC test and the Canetti proportion method. Agreement between the results for the two tests was 82% for SM, 95% for INH, and 89% for PAS. A small number of strains appeared to be sensitive when tested by one method but resistant by the other. MIC determinations were carried out on 83 strains by using Steenken-Smith, Lowenstein-Jensen, and Middlebrook 7H10 media containing a more extended range of concentrations of the test drugs. The MIC values for both SM and dihydrostreptomycin increased on Steenken-Smith medium compared with the other two. INH did not show any medium effect, whereas PAS showed increased MIC values in 7H10 agar. The significance of the comparisons of the MIC values on the various media is discussed in terms of possible changes in the drug sensitivity testing methods used at present in this laboratory.
Nuclease Production and Lysostaphin Susceptibility of
Staphylococcus aureus
and Other Catalase-Positive Cocci
Authors: Lachica R. V. F. , Hoeprich P. D. , Genigeorgis C.
Published: December 2020

Some strains of
Staphylococcus epidermidis
and
Micrococcus
sp. produce nucleases. However, thermal stability was shown to be unique to the nucleases of
S. aureus.
In addition, two micromethods for susceptibility testing to lysostaphin were more precise and convenient than anaerobic glucose fermentation in distinguishing between the genera
Staphylococcus
and
Micrococcus.
Heat-Labile Factor Necessary for Hemagglutination-Inhibition Testing of Horse Sera
Authors: DeMeio Joseph L. , DeSanctis Armand N.
Published: December 2020

Normal and immune sera were obtained from horses immunized with either aqueous, alum, or adjuvant bivalent vaccines containing Milford equine 2 virus. Upon heating at 56 C for 30 min, a factor, required for hemagglutination-inhibition but not complement fixation or neutralization testing, was destroyed. This factor which is present in normal sera does not appear to be complement.
Effect of Sodium Chloride and
p
H on Enterotoxin C Production
Authors: Genigeorgis Constantin , Foda Mohamed S. , Mantis Antony , Sadler Walter W.
Published: December 2020

Growth and production of enterotoxin C by
Staphylococcus aureus
strain 137 in 3% + 3% protein hydrolysate powder N-Z Amine NAK broths with 0 to 12% NaCl and an initial
p
H of 4.00 to 9.83 were studied during an 8-day incubation period at 37 C. Growth was initiated at
p
H values as low as 4.00 and as high as 9.83 at 0% salt level as long as the inoculum contained at least 10
8
cells per ml. Rate of growth decreased as the NaCl concentration was increased gradually to 12%. Enterotoxin C was produced in broths inoculated with 10
8
cells per ml and above and having initial
p
H ranges of 4.00 to 9.83, 4.40 to 9.43, 4.50 to 8.55 and respective NaCl concentrations of 0, 4, and 8%. In the presence of 10% NaCl, the
p
H range supporting enterotoxin C production was 5.45 to 7.30 for an inoculum level of 10
8
cells per ml and 6.38 to 7.30 for 3.6 × 10
6
cells per ml. In repeated experiments in which the inoculum contained 10
8
cells per ml, we failed to demonstrate enterotoxin C production in broths with 12% NaCl and a
p
H range of 4.50 to 8.55 and concentrated up to 14 times. The effect of NaCl on enterotoxin C production followed the same pattern as its effect on enterotoxin B production. As the concentration of NaCl increased from 0 to 10%, yields of enterotoxin B and C decreased to undetectable amounts.
Elutriation and Coulter Counts of
Tetrahymena pyriformis
Grown in Peanut and Cottonseed Meal Media
Authors: Teunisson Dorothea J.
Published: December 2020

Growth of
Tetrahymena pyriformis
W has been used to evaluate nutritional quality of peanut and cottonseed meals. An efficient elutriation method is described for separating cells of this organism from particulate matter left in the substrate (enriched with basal medium) after 4 days of incubation. After elutriation the cells can be counted with a Coulter counter by using calibration procedures which are presented. Elutriation and Coulter counting provide a rapid and efficient method of measuring the growth response of
T. pyriformis
W. Utility of the method is demonstrated by agreement between Coulter counts and visual counts of the cells and by demonstration of a linear response of cell numbers to substrate nitrogen.
Contamination of Sputum Induction Equipment During Patient Usage
Authors: French Morris L. V. , Dunlop Stuart G. , Wetzler Theodore F.
Published: December 2020

Sputum induction equipment was evaluated for its capacity to become contaminated by patients harboring
Mycobacterium tuberculosis.
The mouthpiece, goose-neck, and 10% NaCl solution were found capable of being contaminated by tuberculous patients. Two per cent glutaraldehyde was shown to be an effective means of decontamination. This study indicates that the entire induction apparatus must be cleaned and decontaminated between patients.
Typing of O Antigens of
Vibrio parahaemolyticus
by a Slide Agglutination Test
Authors: Montague T. S. , Le Clair R. A. , Zen-Yoji H.
Published: December 2020

O antigens of
Vibrio parahaemolyticus
can be detected by a slide agglutination test.
Preparation and Standardization of an Australia Antigen Antibody of Equine Origin
Authors: Cabasso V. J. , Nieman R. , Schroeder D. D. , Hok K. A. , Louie R. E. , Mozen M. M.
Published: December 2020

A horse has been immunized with Australia antigen (Au/SH) purified 20-fold by a procedure employing gel filtration of Cohn fraction IV derived from an Au/SH-positive human plasma pool. Hyperimmunization was initiated by the intramuscular injection of 20 ml of a mixture of equal parts of purified Au/SH and complete Freund's adjuvant. The 20-ml volume was divided into four 5-ml doses, two of which were administered on each side of the horse's neck. Booster doses of antigen alone were given as follows: 10 ml intravenously 30 days later and 5 ml intramuscularly on each of days 77 and 205. Au/SH antibody formed readily, beginning on day 17, and was demonstrated by the agar gel double-diffusion technique and the complement fixation test during the subsequent 6 months. Antihuman plasma protein antibodies were effectively removed from the horse serum by one absorption with 1 to 3 volumes of normal human plasma. Abrupt rises in anticomplementary activity observed shortly after the third and fourth antigen injections, when the horse had developed elevated and steady levels of Au/SH antibody, could possibly be due to formation of antigen-antibody complexes. After optimal conditions were determined, an Au/SH antibody reagent pool which met official requirements was prepared. It was found equally suitable for the agar gel double-diffusion, complement fixation, and counterimmunoelectrophoresis test procedures.
R/B Enteric Differential System for Identification of
Enterobacteriaceae
Authors: Smith P. B. , Rhoden D. L. , Tomfohrde Karla M. , Dunn C. R. , Balows A. , Hermann G. J.
Published: December 2020

The R/B Enteric Differential System for identifying enteric bacteria has been evaluated with 451 “unknown” cultures from the stock culture collection of the Center for Disease Control. An average of 89.6% of these cultures were correctly identified by the R/B system, when used as recommended by the manufacturer but without the assistance of serology. This percentage ranged, however, from 47% for
Klebsiella
to 100% for
Serratia
and
Providencia.
Of 11 groups or genera of
Enterobacteriaceae
tested, only three (
Enterobacter, Serratia
, and
Providencia
) were identified with 95% or better accuracy. Four groups (
Arizona, Citrobacter, Escherichia
, and
Salmonella
) attained 90 to 95% accuracy of identification, and three groups (
Edwardsiella, Proteus
, and
Shigella
) scored between 85 and 90% accuracy. We recommend the R/B system as a screening device which is reasonably successful in grouping bacteria but not as a substitute for more exacting conventional procedures.
Virulence and Pathogenesis of Yellow Fever Virus Serially Passaged in Cell Culture
Authors: Converse John L. , Kovatch Robert M. , Pulliam James D. , Nagle Stanley C. , Snyder Ernest M.
Published: December 2020

Viscerotropic virulence of the Asibi strain of yellow fever virus (YFV) for monkeys has been known to be lost after serial passage in HeLa cell monolayers. This phenomenon was investigated in several other mammalian and insect tissue cell lines. Assay in monkeys of original seed virus and of virus after 7 and 11 passages in a porcine kidney cell line (PK) indicated essentially equal infectivity and mortality. Moreover, monkeys receiving the passaged virus exhibited more rapid onset of disease and death than animals infected with original seed virus. Histological changes in animals inoculated with passaged virus were identical to those in animals receiving the seed virus. Virus from later passages in PK cells was also lethal for approximately 50% of the monkeys; however, evidence for progressive attenuation was seen in these preparations. Similar results were obtained with a mosquito (
Aedes aegypti
) cell line. In contrast to results obtained in PK and mosquito cells, YFV became essentially avirulent (nonlethal and less infective) for monkeys after only seven passages in HeLa cell cultures.
Simplified Method of Anaerobic Incubation
Authors: Gardner Mildred , Martin William Jeffery
Published: December 2020

A method is described that obviates the need for vacuum and tanks of gas mixtures for anaerobiosis in the anaerobic incubator.
Cutter for Membrane Filters Used in Sterility Testing
Authors: Russell Elmer C. , Farber Jane F. , Seligmann Edward B.
Published: December 2020

An improved cutter is described for cutting membrane filters in half during the performance of sterility tests on drugs.
Growth of the IB-RS-2 Pig Kidney Cell Line in Suspension Culture and Its Susceptibility to Foot-and-Mouth Disease Virus
Authors: Chapman W. G. , Ramshaw I. A.
Published: December 2020

The adaptation of the pig kidney cell line IB-RS-2, clone 60, to growth in suspension culture is described. When fully adapted, an approximate threefold increase in viable cells was obtained within 72 hr from initial cell concentrations of 5 × 10
5
per ml in culture volumes up to 1,500 ml. The monolayer cells (99th passage level) used to initiate the suspension cultures and the fully adapted suspension cells were shown to have an aneuploid chromosome karyotype, whereas earlier monolayer cultures (32nd passage level) had a pseudodiploid karyotype. Replicate virus titrations in monolayers prepared from suspension-adapted cells, IB-RS-2 monolayer cells, BHK monolayer cells, and in suckling mice showed that the suspension cells had retained sensitivity to foot-and-mouth disease virus. The geometric mean peak infectivity of seven strains of foot-and-mouth disease virus grown in IB-RS-2 suspension cells was 10
8.2
plaque-forming units per ml, with a mean complement-fixing activity of approximately 135 complement-fixing units per ml. These preliminary results indicate that submerged cultures of these cells on an industrial scale may be useful for commercial foot-and-mouth disease vaccine production.
Survey of Interferon Production and Sensitivity in Human Cell Lines
Authors: Moehring J. M. , Stinebring W. R. , Merchant D. J.
Published: December 2020

Seven presumed diploid and 11 established cell lines were studied for their ability to produce free interferon in response to a standardized Newcastle disease virus challenge. Interferon production was evaluated in both serum-containing and serum-free medium. The ability of these cell lines to respond to the application of a standard interferon preparation by becoming resistant to virus was also examined. The diploid lines were distinctly more efficient producers of interferon than were the established lines. They also evidenced a greater requirement for serum to produce their maximum titers, but some were able to produce good titers in serum-free medium. The diploid lines were uniformly more sensitive to the application of exogenous interferon than were the established cell lines and attained greater degrees of virus resistance, but all lines tested displayed measurable sensitivity to interferon.
Effect of Antibiotics on Staphylococcal Hemolysin Production
Authors: Lorian Victor
Published: December 2020

Thirty-seven per cent of 126 strains of
Staphylococcus aureus,
when tested on sheep blood-agar with sensitivity discs containing cephalothin, carbenicillin, oxacillin, penicillin, and cycloserine, produced rings of β-hemolysis surrounding zones of inhibition of bacterial growth. Each strain capable of producing a ring of β-hemolysis did so with at least two of the mentioned antibiotics. None of the other 15 antibiotics tested was associated with a ring of β-hemolysis surrounding any of the zones of inhibition. It appears, therefore, that the β-hemolysis observed was produced by certain strains of
S. aureus
only in association with certain antibiotics.
In Vitro Susceptibility of Strains of
Pseudomonas pseudomallei
to Rifampin
Authors: Alexander A. D. , Williams L. C.
Published: December 2020

Reported high activity of rifampin for
Pseudomonas pseudomallei
could not be verified by extensive in vitro tests conducted with 31 recently isolated strains. Minimal inhibitory concentrations of rifampin were 25 μg/ml for three strains and greater than 25 μg/ml for 28 strains. Rifampin had relatively poor in vitro activity when compared with tetracycline drugs and chloramphenicol antibiotics now commonly used for treating melioidosis.
Susceptibility In Vitro and In Vivo of
Pseudomonas pseudomallei
to Rifampin and Tetracyclines
Authors: Fisher Myron W. , Hillegas Arthur B. , Nazeeri Patsy L.
Published: December 2020

Tests were performed on 64 strains of
Pseudomonas pseudomallei
to compare rifampin, various tetracyclines, and other antibiotics for inhibitory activity in vitro. Rifampin minimum inhibitory concentration (MIC) values generally fell between 25 to 50 μg/ml. For deoxycycline, methacycline, tetracycline, and minocycline, MIC means ranged from 1.3 to 2.7 μg/ml. Delayed treatment tests in subacute mouse infections revealed a better rifampin activity than was expected from its weak activity in vitro, whereas of the others, minocycline appeared superior. None of these five antibiotics demonstrated fully curative effectiveness in terms of mouse survival or eradication of residual infection in organs.
Role of Carbon and Nitrogen Sources in Bacterial Growth and Sporulation
Authors: Singh Raizada M. M.
Published: December 2020

A simple growth medium is reported, in which
Bacillus megaterium
forms heat-stable spores, heat-labile spores, or only vegetative cells by changing the carbon and nitrogen source. Studies carried out in such media could be very useful in elucidating biochemical events which lead to bacterial sporulation.
Serotyping of Noncapsular
Haemophilus influenzae
Authors: Kirkman J. B. , Crawford J. J.
Published: December 2020

A microtechnique is described for agglutination typing of
Haemophilus influenzae.
It also provides a further means for classification and study of noncapsular type-specific strains.
Miniculture Plaquing Technique for Mouse Cytomegalovirus
Authors: Johnson K. P. , Gaddis L. C.
Published: December 2020

A method for plaquing mouse cytomegalovirus under agar in miniature cultures is described. Maximal virus adsorption was found to take approximately 5 hr.
Immunogenicity of Plague Vaccines in Mice and Guinea Pigs
Authors: von Metz E. , Eisler D. M. , Hottle G. A.
Published: December 2020

The median effective doses (ED
50
) of 28 lots of killed
Pasteurella pestis
strain 195/P vaccine were determined in mice and guinea pigs. Mice were injected with vaccine alone, whereas guinea pigs received vaccine suspended in incomplete Freund's adjuvant. Potency ratios of vaccines were obtained by comparing the ED
50
of the test with that of a reference vaccine. Mean potency ratios of 1.82 ± 0.50 in mice and 3.22 ± 0.56 in guinea pigs were obtained, and the difference between these means was significant,
P
= <0.01. The number of organisms in the challenge dose did not significantly affect the ED
50
of a vaccine in guinea pigs. However, irrespective of vaccinating route, nearly 1,000 times as much vaccine was required in the absence of adjuvant as in its presence to produce comparable protective indexes in the guinea pig. The response of guinea pigs did not offer any improvement over mice in evaluating the efficacy of plague vaccines.
Evaluation of the Enterotube System for Identification of Members of the Family
Enterobacteriaceae
Authors: Martin William Jeffery , Yu Pauline K. W. , Washington John A.
Published: December 2020

The Enterotube system was evaluated, in parallel with conventional bacteriological procedures for the identification of members of the family
Enterobacteriaceae
, by using bacterial strains from a variety of clinical specimens and from stock cultures. Excellent agreement between the two test systems was obtained with the following reactions: hydrogen sulfide, indole, Simmons' citrate, glucose, and lactose. Agreement was not as good (<85%) with the urea, phenylalanine deaminase, and dulcitol reactions. The Enterotube lysine decarboxylase test was unsatisfactory. The Enterotube method will correctly identify strains of the family
Enterobacteriaceae
approximately 50% of the time; if identification only as
Klebsiella-Enterobacter-Serratia
group is needed, the method will be correct 85% of the time. On the basis of this evaluation, the Enterotube system appears to be both simple and rapid for the presumptive identification of these bacteria. Because of the limited usefulness of the lysine decarboxylase test, the results obtained by this test system are less reliable than those obtained by conventional methods.
Stimulative Effect of Elemental Sulfur on Siomycin Production by
Streptomyces sioyaensis
Authors: Yagi Sigeo , Kitai Seiji , Kimura Toshiaki
Published: December 2020

The addition of elemental sulfur to the fermentation of
Streptomyces sioyaensis
in a soybean meal medium resulted in a three- to fourfold increase of siomycin. Further experiments on the effect of elemental sulfur during fermentation suggest that one of the key steps stimulating siomycin synthesis is the utilization of thiosulfate, which accumulates in the medium as the result of the oxidation of elemental sulfur.
Oxidation of Elemental Sulfur to Thiosulfate by
Streptomyces
Authors: Yagi Sigeo , Kitai Seiji , Kimura Toshiaki
Published: December 2020

Streptomyces sioyaensis
, which produces the antibiotic siomycin, oxidizes elemental sulfur when added to the culture medium and accumulates thiosulfate in the fermented broth. The accumulated thiosulfate was isolated as the ammonium salt and was identified by melting point, IR spectrum, and paper chromatography. A variety of other streptomycetes also oxidized elemental sulfur and accumulated thiosulfate.
Ultrasonic Synergistic Effects in Liquid-Phase Chemical Sterilization
Authors: Sierra Gonzalo , Boucher Raymond M. G.
Published: December 2020

New methods of sterilization employing a chemical with moderate heat and ultrasonic energy have been devised. Inactivation of high-density bacterial spore suspensions is achieved by treatment with low concentration aqueous acid glutaraldehyde solutions at temperatures above or about 54 C. Low (20 kHz) or high (250 kHz) frequency ultrasonic energy is synergistic with glutaraldehyde. Rapid inactivation may also be achieved by using ultrasonic energy and aqueous alkalinized glutaraldehyde solutions at low (25 C) or moderate (55 C) temperatures. If compared to present room temperature techniques, “surface sterilization” time for contaminated objects can be reduced from hours to minutes.
Relative Sensitivity of Gel Diffusion, Complement Fixation, and Immunoelectroosmophoresis Tests for Detection of Hepatitis-Associated Antigen and Antibody
Authors: Schmidt Nathalie J. , Gee Pinkie S. , Lennette Edwin H.
Published: December 2020

The immunoelectroosmophoresis (IEOP) test was compared with gel diffusion and complement fixation (CF) tests for sensitivity in detecting hepatitis-associated antigen (HAA) in the sera of hepatitis patients, for titration of HAA, and for detection of antibody to HAA. The IEOP test was found to be slightly more sensitive than either gel diffusion or CF tests for
detection
of antigen in the patients' sera. Titers of HAA demonstrated by IEOP were higher than those seen in gel diffusion tests but lower than CF titers. The gel diffusion test with an “enhancement” pattern was found to be more reliable than the other two procedures for detection of low levels of anti-HAA, due to the greater inhibitory effect of an antigen excess in the IEOP system and the possible masking of low levels of antibody by anticomplementary activity in the CF test system. Staining of immunoprecipitates in the IEOP test contributed little to the sensitivity of the test for detection of HAA.
Production of Double Zones of Hemolysis by Certain Strains of Hemolytic Streptococci of Groups A, B, C, and G on Heart Infusion Agar
Authors: Noble Robert C. , Vosti Kenneth L.
Published: December 2020

This report describes the appearance of a double zone of hemolysis around surface colonies of certain strains of streptococci of groups A, B, C, and G incubated aerobically on sheep blood-Heart Infusion Agar. The occurrence of the altered hemolytic pattern was related to peroxide production by the organism. Anaerobic conditions and the incorporation of catalase into the agar abolished the double-zone pattern and caused reversion of the organisms to a beta-hemolytic pattern. The double-zone pattern can be confused with alpha hemolysis on surface growth.
Effect of Soy Proteins on the Growth of
Clostridium perfringens
Authors: Busta F. F. , Schroder D. J.
Published: December 2020

Proteins that are used to fabricate imitation foods such as synthetic meats were evaluated for stimulative or inhibitory effects on the growth of
Clostridium perfringens.
Growth rate and extent were measured in thioglycolate medium without dextrose. This liquid medium contains Trypticase (BBL) which served as the protein control. For comparison, various soy proteins, synthetic meats, beef, turkey, sodium caseinate, and combinations of each were substituted for Trypticase. Meat loaf systems were also employed to determine the effects of protein additives to meat under actual meat loaf conditions. Growth of
C. perfringens
type A, strain S40, was measured in the respective media at 45 C at a
p
H of 7.0 and an
E
h
of below −300 mv. Viable populations were enumerated by agar plate techniques on Trypticase-sulfite-yeast-citrate-agar incubated anaerobically (90% N
2
-10% CO
2
) for 18 hr at 35 C. When compared to Trypticase, some soy proteins had stimulative effects on the growth of
C. perfringens
, whereas sodium caseinate and some soy proteins were inhibitory. In liquid medium in which meat or soy meat was the source of protein, there was a marked stimulation by beef, chicken, and soy beef. Soy chicken supported growth at a rate less than observed with Trypticase. Under actual meat loaf conditions, the addition of soy meat or protein additives to beef did not affect the growth of
C. perfringens.
The addition of protein additives to turkey meat loaves significantly enhanced the rate of growth of
C. perfringens.
The stimulative effects of some soy proteins are significant in relation to control of foodborne disease.
Effect of Relative Humidity and Temperature on Airborne Venezuelan Equine Encephalitis Virus
Authors: Ehrlich Richard , Miller Sol
Published: December 2020

Inactivation of airborne Venezuelan equine encephalitis (VEE) virus disseminated from liquid suspensions or from lyophilized preparations as 1- to 5-μm particles was investigated under various conditions of relative humidity and temperature in a 2,500-liter static aerosol chamber. Relative humidity ranging from 18 to 90% at 24 C and temperature ranging from −40 to 24 C had no marked effect on the biological decay rate or the recovery of viable airborne VEE virus disseminated from liquid suspensions. However, at 49 C a significant increase in the biological decay rate and decrease in aerosol recovery of the VEE virus were observed. Airborne lyophilized VEE virus was significantly affected by relative humidity. An increase in relative humidity from 20 to 90% resulted in progressive decrease in aerosol recovery of viable VEE virus. A twofold reduction in aerosol recovery of the lyophilized virus was observed at and above 29 C as compared to the lower temperatures studied. However, the differences among biological decay rates of lycphilized VEE virus were not significant within temperature range of −40 to 38 C.
Sodium Chloride Tolerance of Terrestrial Fungi
Authors: Tresner H. D. , Hayes Jean A.
Published: December 2020

A survey was made of the NaCl tolerance of 975 species of terrestrial fungi selected from the major taxonomic classes. The penicillia and aspergilli were notably the most resistant with the majority of their species able to grow in the presence of 20% or more of NaCl. The
Basidiomycetes
, as a class, were decidedly the least tolerant with over half the species unable to withstand more than 2% NaCl. Uniformity of tolerance by multiple strains of various species suggests that this may provide a useful taxonomic criterion.
Action of
Pseudomonas fragi
on the Proteins of Pig Muscle
Authors: Tarrant P. J. V. , Pearson A. M. , Price J. F. , Lechowich R. V.
Published: December 2020

Considerable salt-soluble protein degradation was observed in pork muscle inoculated with
Pseudomonas fragi.
During a 20-day incubation period at 10 C, the samples proceeded to rank spoilage or putrefaction. There was a large decrease in the salt-soluble protein fraction and a corresponding increase in nonprotein nitrogen. Disc gel electrophoretic patterns showed that breakdown of the salt-soluble proteins had occurred after incubation for 20 days. During incubation for 10 days at 10 C,
P. fragi
produced large amounts of extracellular proteolytic activity in ground pork. Most of the proteolytic activity appeared immediately after spoilage occurred. However, a significant increase in the ability to hydrolyze casein and a slight increase in the ability to hydrolyze denatured hemoglobin occurred prior to spoilage.
Surface Decontamination in an Autoclave Chamber with Formaldehyde Gas
Authors: Sweet Haven C.
Published: December 2020

A simple device for the conversion of a standard steam autoclave into a formalde-hyde gas sterilization chamber is described.
Microbial Flora of Pecan Meat
Authors: Chipley J. R. , Heaton E. K.
Published: December 2020

Microorganisms found associated with commercially shelled pecan meats are numerous and varied. No bacteria and only two fungal microorganisms,
Aspergillus clavatus
and
Tricothecium
species, were found on aseptically shelled pecans.
Variations in the Metal Content of Some Commercial Media and Their Effect on Microbial Growth
Authors: Bovallius Å. , Zacharias B.
Published: December 2020

The cation content in commercial media obtained from two manufacturers showed considerable variation. Even different batches of the same make were found to be inconsistent in the content of metal ions. With cultures of
Cytophaga
sp. and
Yersinia pseudotuberculosis
in base media, growth stimulation was dependent on additions of certain commercial media. It could be demonstrated that this stimulation was derived solely from increased Mg
2+
concentration in the media.
Degradation of Linuron and Some Other Herbicides and Fungicides by a Linuron-Inducible Enzyme Obtained from
Bacillus sphaericus
Authors: Engelhardt G. , Wallnöfer P. R. , Plapp R.
Published: December 2020

Linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea] induces the formation of an enzyme (acylamidase) responsible for the degradation of a large variety of different herbicides and fungicides of the acylanilide and phenylurea type. The former type is degraded at a rate at least 10 times higher than the latter.
Fractionation and Composition Studies of Skin Test-Active Components of Sensitins from
Coccidioides immitis
Authors: Anderson Kenneth L. , Wheat Robert W. , Conant Norman F.
Published: December 2020

Coccidioidin skin-test activities from mycelial culture filtrates and autolysates were partially purified. Major chemical constituents included 3-
O
-methylmannose, mannose, and amino acids.
Thermal Resistance of Certain Oncogenic Viruses Suspended in Milk and Milk Products
Authors: Sullivan Robert , Tierney John T. , Larkin Edward P. , Read Ralston B. , Peeler James T.
Published: December 2020

Thermal destruction rate curves were determined for adenovirus 12, reovirus 1, and herpes simplex virus in sterile milk, raw milk, raw chocolate milk, and raw ice cream mix. At 40 to 60 C, the curves were asymptotic to the base line. At 65 C, which is near the pasteurization standard, the curves approached a first-order reaction. Thermal resistance studies, by means of in vivo assays, of Moloney and Rauscher leukemia viruses and Moloney and Rous sarcoma viruses indicated that Rous sarcoma was the most resistant. A comparison of the 12D processes of Rous sarcoma virus, reovirus 1, adenovirus 12, and herpes simplex virus in ice cream mix (the most protective of the suspending menstrua studied) with the U.S. Public Health Service pasteurization standard indicated an adequate safety factor in current pasteurization practices.
Soft-Shell Clam,
Mya arenaria
, a Convenient Laboratory Animal for Screening Pathogens of Bivalve Mollusks
Authors: Tubiash Haskell S.
Published: December 2020

Attempts to introduce infectious or foreign material into oysters and other bivalve mollusks usually involve force or trauma because of immediate, prolonged adduction of the tightly closing valves. The soft-shell clam,
Mya arenaria
, is unable to seal its valves completely and relaxes readily, exposing soft tissue and a large siphon. This species is free from fouling organisms and is readily available at all seasons in the New England and mid-Atlantic areas. Suspensions of five strains of
Vibrio
sp. that cause bacillary necrosis in larval and juvenile bivalve mollusks were injected into the heart, siphon tissue, and the incurrent and excurrent siphon lumina of soft-shell clams. All vibrio strains caused significant mortality, usually within 2 days. Heaviest losses resulted from heart and excurrent siphon injections. No mortality occurred in control clams injected with seawater, broth,
Serratia
sp., and
Escherichia coli.
The soft-shell clam appears to be a useful animal for testing the pathogenicity of marine microorganisms for bivalve mollusks.