bluuebunny/crossref_metadata_2025 huggingface dataset:
Coagulase and Deoxyribonuclease Activities of Staphylococci Isolated From Clinical Sources
Authors: Morton Harry E. , Cohn Judith
Published: December 2020

A total of 504 clinical isolates of the family
Micrococcaceae
were tested for coagulase, deoxyribonuclease, clumping factor, and phosphatase to determine whether there is a correlation between the results of these tests and the pathogenicity of staphylococci. In the tests for coagulase production, it was found that either human or rabbit plasma could be used with broth cultures, whereas rabbit but not human plasma was satisfactory when microorganisms removed from solid culture medium were used. Deoxyribonuclease production correlated better than the fermentation of mannitol with coagulase production. The use of methyl green, Toluidine Blue O, or acridine orange offered no advantage over the use of HCl for detecting the production of deoxyribonuclease. Neither the presence of clumping factor nor the production of phosphatase correlated well with coagulase production. Strains of staphylococci that did not produce coagulase and deoxyribonuclease were isolated as frequently as, and from a greater variety of clinical sources than, strains which produced these substances. It is concluded that the production of coagulase and deoxyribonuclease are properties of staphylococci which are not necessarily indicative of potential pathogenicity of the organisms for man.
Ruminal Bacterial Degradation of Benzo(b)-thien-4-yl Methylcarbamate (Mobam) and Effect of Mobam on Ruminal Bacteria
Authors: Williams Phletus P. , Stolzenberg Rosa L.
Published: December 2020

Mixtures of ruminal bacteria degraded benzo(b)thien-4-yl methylcarbamate (Mobam) to 4-hydroxybenzothiophene, CO
2
, and polar product(s). The metabolite, 4-hydroxybenzothiophene, was identified (after acetylation) by comparative infrared and mass spectrometry with an authentic sample. Carbon dioxide and polar product(s) were produced by degradation of the methylcarbamate moiety. Ten previously characterized strains of ruminal bacteria with diverse physiological capabilities did not degrade Mobam. However, three tributyrin-hydrolyzing strains were isolated that did degrade Mobam. Mobam inhibited growth of two of ten strains isolated on Mobam-free glycerol-tributyrin enrichment medium. One of these strains was also sensitive to 2-carbomethoxy-propene-2yl dimethyl phosphate (Phosdrin). Mobam prevented some ruminal bacteria from producing zones of hydrolysis in tributyrin emulsion media and inhibited some ruminal bacteria from degrading 1-naphthyl acetate and fluorescein-3′,6′-diacetate.
Detection of Chlamydial Antibodies in Animal Sera by Double Diffusion in Gel
Authors: Barron Almen L. , Caste Paul G. , Paul Bimla , Page Leslie A.
Published: December 2020

Postinoculation sera collected from pigeons, turkeys, guinea pigs, sheep, a calf, a rabbit, and a horse experimentally infected with various strains of
Chlamydia psittaci
yielded a high incidence of positive reactions when tested by double diffusion in gel. Antigen was a deoxycholate extract of SA-2 strain of
C. trachomatis
. Good correlation was obtained with results of complement fixation tests, whereas double diffusion in gel was less sensitive. Immunoelectrophoresis of the antigen revealed presence of two antigens in the extract.
Estimating the Number of Organisms in Quantal Assays
Authors: Wyshak G. , Detre K.
Published: December 2020

It has been demonstrated by virologists that, when procedural difficulties can be overcome and host variation can be eliminated, dosage-response data from virus assays conform with the one-particle theory of infection for both plaque counts and tissue cultures. Based on this theory, the number of virus particles from quantal virus assays can be estimated. Here a set of tables is presented from which the number of estimated particles can be obtained directly for several dilution factors and a number of dilution levels. Maximum likelihood estimation of particle counts is also illustrated using a computer program that we have prepared.
Characterization of the Repair of Injury Induced by Freezing
Salmonella anatum
Authors: Ray B. , Janssen D. W. , Busta F. F.
Published: December 2020

Fast freezing and slow thawing of
Salmonella anatum
cells suspended in water resulted in injury of more than 90% of the cells that survived the treatment. The injured cells failed to form colonies on the selective medium (xyloselysine-peptone-agar with 0.2% sodium deoxycholate) but did form colonies on a nonselective (xylose-lysine-peptone-agar) plating medium. In Tryptic soy plus 0.3% yeast extract broth or minimal broth, most of the injured cells repaired within 1 to 2 hr at 25 C. Tryptic soy plus yeast extract broth supported repair to a greater extent than minimal broth. Phosphate or citrate at concentrations found in minimal broth supported repair of some cells. MgSO
4
, when present with inorganic phosphate or citrate or both, increased the extent of repair. The repair process in the presence of phosphate was not prevented by actinomycin D, chloramphenicol, and D-cycloserine, but was prevented by cyanide and 2,4-dinitrophenol (only at
p
H 6). This suggested that the repair process might involve energy metabolism in the form of adenosine triphosphate. The freeze-injured cells were highly sensitive to lysozyme, whereas unfrozen fresh cells were not. In the presence of phosphate or minimal broth this sensitivity was greatly reduced. This suggested that, at least in some of the cells, the injury involved the lipopolysaccharide of the cell wall and adenosine triphosphate synthesis was required for repair.
Laboratory Mill for Pulverizing and Homogenizing Nail Specimens as an Aid to Microscopy and Culture Confirmation of Onychomycosis
Authors: Luedemann George M. , LeBreton Ernest
Published: December 2020

A small mill has been developed for reducing nail clippings to a convenient size for microscopy and inoculation onto isolation media. The milling process acts to pulverize and homogenize the specimen. The use of a homogeneous sample in microscopy increases the opportunity for the discovery of fungal hyphae in a specimen. The use of a pulverized specimen increases the possibility of culture isolation by permitting greater numbers of potentially viable fungal cells to come into direct contact with the isolation medium.
Reproducibility of a Neuraminidase Inhibition Test Employed to Measure Anti-Influenza Neuraminidase Antibody
Authors: Hennessy A. V. , Davenport F. M.
Published: December 2020

The standard deviation was determined for 146 replications of the neuraminidase inhibition test for antineuraminidase antibody employing two ferret antisera and the recombinant viruses X-15 and X-15(HK). The standard deviation found was 0.612 log
2
and is a quantitative estimate of the reproducibility of the test.
Effect of Several Clay Minerals and Humic Acid on the Survival of
Klebsiella aerogenes
Exposed to Ultraviolet Irradiation
Authors: Bitton Gabriel , Henis Y. , Lahav N.
Published: December 2020

The effect of various clay minerals and humic acid on the survival of
Klebsiella aerogenes
exposed to ultraviolet (UV) irradiation was investigated. A protective effect was observed and found to depend on the specific light absorption and light scattering properties of the clay minerals and the humic acid used. The higher the specific absorption, the better was the survival of
K. aerogenes
after UV irradiation. Bacterial survival was lower in clays saturated with divalent cations (Ca, Zn) than in those homoionic to monovalent cations (K).
Use of Gas Chromatography for Determining Catabolic Products of Arginine by Bacteria
Authors: Moss C. Wayne , Lambert M. A. , Cherry W. B.
Published: December 2020

A rapid and sensitive procedure for determining catabolic products of arginine metabolism by bacteria was developed. The method consists of inoculating a solution of L-arginine with a heavy cell suspension of the test organism. After a 2-hr incubation period, dissimilation products (citrulline, ornithine, agmatine, putrescine) are converted to volatile derivatives and analyzed by gas-liquid chromatography. Compared with conventional microbiological tests, the new procedure is rapid and can be used for sensitive quantitative measurements of specific metabolites from arginine.
Quantitative Urine Culture Method Using a Plastic “Paddle” Containing Dual Media
Authors: Craig William A. , Kunin Calvin M.
Published: December 2020

A new dip-inoculum method for quantitative urine culture is described which utilizes a dual-chambered plastic “paddle” housing both a general purpose and differential medium. Comparative bacterial counts of 1,000 clinical specimens using the pour plate and this device were identical in 82.9% and within a factor of five in 95.6%. The “paddle” detected all but 19 of 258 specimens (92.6%) with 100,000 or greater colonies per ml. This simple, convenient method should allow more extensive use of quantitative urine culture in the diagnosis and follow-up of patients with urinary tract infections in office practice. It should not be considered as a substitute for the more definitive pour plate method or for standard methods for characterization of bacteriological species when more exact information is required.
Comparative Immunogenicities of Chikungunya Vaccines Propagated in Monkey Kidney Monolayers and Chick Embryo Suspension Cultures
Authors: White Arthur , Berman Sanford , Lowenthal Joseph P.
Published: December 2020

A comparative study was made of Formalin-inactivated Chikungunya vaccines prepared from the virus propagated in African green monkey kidney monolayers and concentrated chick embryo suspension cultures. The vaccine prepared in the chick embryo suspension cultures was significantly more protective to mice against a live homologous virus challenge and stimulated the production of 4 to 5 times more circulating antibodies than the vaccine prepared with virus grown in African green monkey kidney monolayer cultures.
Phase Variation of Andrewes in
Salmonella enteritidis
Bioserotype Paratyphi-A
Authors: McWhorter Alma C. , Huntley Geraldine A. , Ewing William H. , Hermann George J.
Published: December 2020

The natural occurrence of a strain of
Salmonella enteritidis
bioserotype Paratyphi-A is reported, in which the flagellar antigens segregated readily into normal phase 2 antigens and mixtures of normal phase 1 and phase 2 antigens, and in which phase variation of Andrewes was demonstrated with ease.
Antigenic Relationships Among Strains of
Vibrio parahaemolyticus
Authors: Twedt R. M. , Spaulding P. L. , Johnson H. M.
Published: December 2020

The antigenic relationships of 79 strains of
Vibrio parahaemolyticus
representing 46 assigned K-types were studied by tube agglutination. Homologous titers of 46 anti-K sera ranged from 80 to 2,560. All but three sera exhibited from one to six heterologous reactions, the majority of which gave titers of ≤20, but 19 sera showed cross-reactions whose titers exceeded 40. Nine reciprocal and 16 unilateral relationships were described. Some of the cross-reactions involved heat-extractable K-antigens, as determined by absorption with nonheated and heated heterologous antigens, whereas others did not involve K-antigens since absorption with the heterologous antigens had no effect on the homologous systems. On the basis of the reactions of selected antisera to the O-antigens of some of the K-strains, the cross-reactions could not be explained solely on the basis of O-specificities.
High-Intensity Vapor Lamp for Biological Research
Authors: LeBuis Donald A. , Lorenz John R. , Eisler William J. , Webb Robert B.
Published: December 2020

A vapor arc light source has been adapted to the study of the lethal action on bacteria of near-ultraviolet (UV) and visible light. Its use makes possible much shorter exposure times than could be obtained from previously available sources. The output of radiant energy is sufficient to provide a fairly detailed action spectrum for lethality in the long-UV and visible region without the addition of exogenous sensitizers. Populations of cells of
Escherichia coli
WP2 were inactivated through five log
10
cycles with light at 460 nm. Significant inactivation also was obtained with light at 550 and 650 nm.
Agar Block Technique for Identification of Mycoplasmas by Use of Fluorescent Antibody
Authors: Baas E. J. , Jasper D. E.
Published: December 2020

A procedure for staining mycoplasmata colonies directly on agar blocks for examination by fluorescent microscopy is described. Areas of the agar surface appropriate for staining were demarcated by use of Lucite cylinders. Direct fluorescent-antibody staining was superior to indirect staining. The technique was very useful for determining whether cultures were mixed and for identification of mycoplasmas in either pure or mixed cultures.
Recognition of Group D Streptococcal Species of Human Origin by Biochemical and Physiological Tests
Authors: Facklam Richard R.
Published: December 2020

The speciation of 262 strains of group D streptococci isolated from human sources is described. One hundred forty-two isolates from blood cultures were included; 96 of these were submitted as isolates from clinical cases of subacute bacterial endocarditis. The results show that 98
Streptococcus faecalis
, 29
S. faecalis
var.
zymogenes
, 44
S. faecalis
var.
liquefaciens
, 27
S. faecium
, 13
S. durans
, 44
S. bovis
, and 7 unspeciated
S. bovis
-like group D isolates were identified. No
S. faecium
var.
casseliflavus, S. equinus
, or
S. avium
(group Q streptococci) were identified among the human isolates. The speciation procedures and techniques are detailed. The procedures and limitations of the tests used are discussed. Ninety-eight percent of the 262 strains were speciated by a spectrum of tests that allowed us to recognize atypical as well as typical strains within species.
New Technique for Biotyping
Authors: Guinée P. A. M. , Leeuwen W. J. Van , Jansen W. H.
Published: December 2020

An efficient technique for biotyping, using disposable trays instead of glass tubes and agar instead of liquid media, is described.
Improved Procedure for Identification of Group D Enterococci with Two New Media
Authors: Lee Wie-Shing
Published: December 2020

With the use of Pfizer selective enterococcus medium as a screening process, tyrosine decarboxylase (TD) medium and D-broth were devised for additional confirmation of the identification of group D enterococci. The semisolid TD medium was used in a method similar to inoculating a motility tube. TD activity was indicated by clarification of the medium near the line of inoculation because the insolubility of tyrosine provided an otherwise milky suspension. D-broth was used to show the tolerance of organisms to 6.5% NaCl at
p
H 8.2. In addition, enterococcal species (except
Streptococcus durans
) could also be demonstrated by the acid formation due to the fermentation of mannitol or arabinose. With this improved system, about 97% of enterococci could be accurately identified and confirmed.
Activation of a Toxic Component of
Clostridium botulinum
Types C and D by Trypsin
Authors: Eklund M. W. , Poysky F. T.
Published: December 2020

When the Stockholm and 468C strains of type C and the 1873 strain of type D
Clostridium botulinum
are “cured” of their prophages, they simultaneously discontinue the production of their dominant toxins (C
1
and D), but they continue to produce a second antigenically monospecific toxin (C
2
). These “cured” strains of types C and D therefore become indistinguishable with respect to the toxin produced. Fifteen type C cultures received from other laboratories discontinued to produce the dominant toxin when subcultured in broth. The C
2
toxin, however, was produced by eight of these cultures. The C
2
toxin is produced by these cultures as a protoxin that requires treatment with trypsin before its toxicity can be demonstrated. Of the 21 type C cultures that produce the C
1
toxin, 20 were shown to produce the C
2
toxin. The filtrates of 14 of these cultures required trypsin treatment before the C
2
toxicity could be demonstrated. Low levels of toxicity could be demonstrated in the six remaining culture fluids without trypsin; toxicity, however, was increased with trypsin.
Potential Production and Detoxification of Penicillic Acid in Mold-Fermented Sausage (Salami)
Authors: Ciegler A. , Mintzlaff H.-J. , Weisleder D. , Leistner L.
Published: December 2020

About 10% of 346
Penicillium
cultures isolated from mold-fermented sausage synthesized the toxic metabolite penicillic acid on liquid media. Five of these producing cultures inoculated onto sausage failed to produce this toxin in up to 70 days of ripening. Several amino acids normally occurring in meat (cysteine, glutathione, arginine, histidine, and lysine) were found capable of readily reacting with penicillic acid. The adducts formed by the reaction between cysteine or glutathione with penicillic acid were identified and found to be non-toxic to mice, quails, and in the rabbit skin test but exhibited toxicity to the chick embryo. Hypotheses accounting for this residual toxicity are advanced.
Escherichia coli
O Antigen Typing by Means of a Mechanized Microtechnique
Authors: Guinée P. A. M. , Agterberg C. M. , Jansen W. H.
Published: December 2020

A mechanized microtechnique for the serological typing of
Escherichia coli
cultures is described.
Rapid Complement Fixation Technique for Estimating Complement-Fixing Antigen Elution Profiles of Viruses from Gel Filtration Columns
Authors: Cornesky Robert A. , Hammon William McD. , Sather Gladys E. , Atchison Robert
Published: December 2020

The complement fixation elution profiles of dengue-2 virus-infected suckling mouse brain supernatant fluids from Sephadex G-200 columns were compared by the antigen end-point titration procedure and by a complement dilution technique. The latter technique was found to be a quick method for approximating the complement-fixing antigen in eluates.
Elimination of
Mycoplasma
Contaminants from Virus Stocks by Treatment with Nonionic Detergents
Authors: Wolford Ronald G. , Hetrick Frank M.
Published: December 2020

Five nonionic detergents (Tweens 20, 40, 60, and 80, and Triton WR-1339) were tested for their ability to inactivate four
Mycoplasma
species which are common contaminants of animal cell cultures. Tween 20 was found to be the most effective, in that a concentration of 2.5 mg/ml completely inactivated cultures of
M. hominis, M. hyorhinis
, and
Acholeplasma laidlawii
within 1 hr and a culture of
M. orale
within 3 hr. The other detergents exhibited various degree of activity against the different mycoplasmas, with Triton WR-1339 being the least effective. The virucidal activity of the detergents was determined for six viruses. All four Tween compounds were highly virucidal for herpes simplex virus. Tween 20 also exhibited virucidal effects against vesicular stomatitis virus, California encephalitis virus, and Newcastle disease virus, and Tween 80 was found to be active against California encephalitis and Newcastle disease viruses. Detergent treatment procedures were effective in two instances in eliminating mycoplasma contaminants from virus preparations while the preparations retained most of the viral infectivity. The limitations of this technique for routine use are discussed.
Evaluation of the Qualitative and Automated Quantitative Microhemagglutination Assay for Antibodies to
Treponema pallidum
Authors: Coffey E. M. , Bradford L. L. , Naritomi L. S. , Wood R. M.
Published: December 2020

Qualitative and quantitative microhemagglutination assays for antibodies to
Treponema pallidum
(MHA-TP) were performed on 314 syphilitic and 597 presumably nonsyphilitic sera, and the results were compared with those of the fluorescent treponemal antibody-absorbed (FTA-ABS), the
Treponema pallidum
immobilization (TPI), and the Veneral Disease Research Laboratory (VDRL) tests. MHA-TP sensitivity was similar to that of the other tests in all stages of syphilis except primary syphilis, in which MHA-TP reactivity was only 64% compared with 82% in the FTA-ABS test, 73% in the VDRL test, and 67% in the TPI test. MHA-TP specificity was satisfactory and comparable to that of the other treponemal tests. Quantitation of the MHA-TP test was automated by use of Autotiter II equipment. Titers tended to become elevated later in the course of syphilis and to remain elevated longer than did VDRL titers. Reproducibility of the quantitative MHA-TP test was satisfactory, with duplicate tests agreeing within one doubling dilution on 97.5% of 351 reactive sera. Poor reproducibility was obtained with sera giving minimal reactions in the qualitative test, and such sera should be routinely retested. The MHA-TP is less time-consuming and costly than the FTA-ABS test and could be used in conjunction with the VDRL or another reagin test for syphilis to eliminate a large number of the FTA-ABS tests now required.
Lactose-Hydrolyzing Enzymes of
Lactobacillus
Species
Authors: Premi L. , Sandine W. E. , Elliker P. R.
Published: December 2020

β-Galactosidase (β-gal, EC 3.2.1.23) and β-D-phosphogalactoside galactohydrolase (β-Pgal) activities were observed in all of 13
Lactobacillus
species studied except
L. casei
and
L. buchneri
. Only the latter enzyme was detected in nine strains of
L. casei
. The β-gal from
L. thermophilus
and the β-Pgal from
L. casei
were purified and characterized. In comparison with β-gal, the β-Pal was slightly less active (
V
max
values were 28.9 and 50.0 μmoles per mg per min, respectively), but the substrate affinitives were similar (
K
m
values were 1.69 × 10
-3
M and 1.59 × 10
-3
M, respectively). Although the two enzymes had similar amino acid compositions, the molecular weight of β-gal was 5.4 × 10
5
and that of β-Pgal was 1.3 × 10
5
. The β-gal from
L. thermophilus
and the β-Pgal from
L. casei
had optimal temperature and
p
H activity values of 55 C at
p
H 6.2 and 37 C at
p
H 5.0, respectively. The complete absence of β-gal from a homofermentative
Lactobacillus
species of industrial importance is further evidence of the heterogeneity of this genus.
Enteric Bacterial Growth Rates in River Water
Authors: Hendricks Charles W.
Published: December 2020

Enteric bacteria, including stocked strains of pathogenic species and organisms naturally present in the stream, were capable of growth in a chemostat with autoclaved river water taken 750 m below a sewage outfall. Maximal specific growth rates for all organisms occurred at 30 C, whereas culture generation times ranged between 33.3 and 116 hr. Of the six laboratory strains of enteric species used,
Escherichia coli
and
Enterobacter aerogenes
grew at generation times of 34.5 and 33.3 hr, respectively, while the remaining
Proteus, Arizona, Salmonella
, and
Shigella
spp. reproduced at a rate two to three times slower than the coliforms. Little or no growth occurred in the water at incubation temperatures of 20 and 5 C, and death was observed for
Salmonella senftenberg
at 20 and 5 C and for
E. aerogenes
and
Proteus rettgeri
at 5 C. When enteric bacteria naturally present in the river water were employed in similar experiments, coliform bacteria demonstrated a generation time of approximately 116 hr, whereas fecal coliforms failed to grow. Growth of the bacteria from the river demonstrated a periodicity of approximately 100 hr, which suggests that much of the growth of these organisms in the chemostat may be on the glass surfaces. This phenomenon, however, was not observed with any of the stocked enteric species. Neither the stock cultures nor the aquatic strains were capable of growth in autoclaved river water taken above the sewage outfall at the three temperatures tested.
Fluorometric Determination of Deoxyribonucleic Acid in Bacteria with Ethidium Bromide
Authors: Donkersloot J. A. , Robrish S. A. , Krichevsky M. I.
Published: December 2020

A simple, sensitive, and rapid method is presented for the determination of deoxyribonucleic acid (DNA) in both gram-positive and gram-negative bacteria. It is based upon the fluorometric determination of DNA with ethidium bromide after alkaline digestion of the bacteria to hydrolyze the interfering ribonucleic acid. The assay takes less than 2 hr. Its sensitivity is at least 0.2 μg of DNA in a final solution of 4 ml and it uses commonly available filter or double monochromator fluorometers. Judicious choice of light source and filters allows an additional 10-fold increase in sensitivity with a filter fluorometer. Turbidity caused by bacteria or insoluble polysaccharides does not interfere with the fluorescence measurements. There was no significant difference between the results obtained with this method and those obtained with the indole and diphenylamine methods when these assays were applied to
Escherichia coli
and sucrose- or glucose-grown
Streptococcus mutans
. The method was also tested by determining the specific growth rate of
E. coli
. This new procedure should be especially useful for the determination of bacterial DNA in dilute suspensions and for the estimation of bacterial growth or DNA replication where more conventional methods are not applicable or sensitive enough.
Elemental Analysis of Vitamin-Free Casamino Acids
Authors: Nolan Richard A. , Nolan William G.
Published: December 2020

The elemental composition of three lots of vitamin-free Casamino Acids (Difco) was determined using X-ray fluorescence, atomic absorption, and colorimetric techniques.
Isolation and Characterization of an Isolate (HN) of Marek's Disease Virus with Low Pathogenicity
Authors: Cho B. R. , Kenzy S. G.
Published: December 2020

A cytopathic agent was isolated and characterized as an isolate of Marek's disease herpesvirus (MDHV) with low pathogenicity, and referred to as the HN isolate. This isolate of MDHV did not cause clinical Marek's disease (MD) or death in a highly susceptible line of chickens within 5 weeks after exposure. Gross lesions of limited extent were noted in a few of the inoculated birds. Microscopic nerve lesions in the inoculated and contact-infected birds were invariably minimal, closely resembling C-type MD lesions.
Mycobacterial Agglutination-Inhibition Test
Authors: Richards W. D. , Eacret W. G.
Published: December 2020

The mycobacterial agglutination-inhibition test (MAIT) is described as a modification of the mycobacterial agglutination of Schaefer (MATS). It is an organized assemblage of absorption and agglutination tests which is especially useful in the identification of
Mycobacterium avium
isolates normally excluded from serological identification because of unstable cell suspension characteristics. The identity of 100 unstable
M. avium
and 3 unstable
Mycobacterium intracellulare
isolates was determined by the MAIT method and by animal pathogenicity tests. The comparability of the MAIT and MATS methods was demonstrated by testing 10 stable
M. avium
and 10 stable
M. intracellulare
isolates by both methods and obtaining the same serological identification for each culture. The reproducibility of the MAIT was confirmed when the same result was obtained in three consecutive tests on each of the 123 cultures used in this evaluation.
Optimization of the Interferon Assay Using Inhibition of Semliki Forest Virus-Ribonucleic Acid Synthesis
Authors: Koblet Hans , Kohler Ursula , Wyler Robert
Published: December 2020

The method for assaying chicken interferon by its inhibition of viral ribonucleic acid (RNA) synthesis was optimized for the chicken embryo fibroblast-Semliki Forest virus (SFV) system, with respect to time, multiplicity of infection, and addition of actinomycin D and
3
H-uridine. Incorporation of
3
H into viral RNA is reproducible, and amounts to 10
4
to 2 × 10
4
counts per min per uninhibited culture per 1 μCi per 6 hr. The assay may be carried out in less than 1 day and is sensitive (0.05 units/ml) and exact (±20% of the mean titers on different days); it can be used for purification procedures as well.
Environmental Factors Correlated with Size of Bacterial Populations in a Polluted Stream
Authors: Brasfeild Helen
Published: December 2020

Samples of water were taken from a polluted zone of the Gallinas River and analyzed as to numbers of total bacteria, coliforms, and fecal streptococci. Environmental factors measured were temperature,
p
H and concentrations of detergent, nitrate plus nitrite nitrogen, sulfate, chloride, bicarbonate, and phosphate. Thirty-two observations were made from 12 March through 22 July 1971. Stepwise multiple linear regression analyses of the data were carried out by computer to determine which of the environmental factors were significantly correlated with numbers of bacteria present. A multiple linear regression equation was constructed for each bacteriological parameter as a function of significant variables only. Log total bacteria was correlated positively with bicarbonate, phosphate, and detergent concentrations. Log coliforms was correlated positively with phosphate and sulfate concentrations and negatively with chloride concentration. Log fecal streptococci was correlated positively with bicarbonate and chloride concentrations.
Pathology of Exfoliated Oropharyngeal Epithelial Cells Infected with Wild-Type Adenovirus
Authors: McCormick David P. , Galapon Quirino , Berling Carl
Published: December 2020

Adenovirus disease was diagnosed in 2 hr by staining exfoliated infected oropharyngeal cells with fluorescein-tagged rabbit antisera to adenovirus types 4 and 7. The method was as sensitive as the standard virus isolation procedures, but serological cross reactions were observed. Viral antigens were detected in both the nucleus and cytoplasm of infected cells. Infection was accompanied by the outpouring of large numbers of polymorphonuclear leukocytes and smaller numbers of mononuclear cells. The method provides a model for the study of the cellular response to viral upper respiratory disease.
Ultrahigh-Temperature Activation of a Low-Temperature
Bacillus subtilis
Spore Germination System
Authors: Adams D. M. , Busta F. F.
Published: December 2020

Exposure of
Bacillus subtilis
A spores to 115 to 125 C for several seconds activated a low-temperature germination system that remained dormant after a heat treatment that activated the normal
l
-alanine- and glucose-stimulated germination systems. The low-temperature germination system was characterized by an optimum temperature lower than that of the
l
-alanine or glucose germination systems (30 C versus 45 C), germination in the absence of exogenous germination stimulants, and the capacity for heat-induced deactivation and subsequent reactivation. The rates of activation at 115 to 125 C were exponential and were not influenced by a previous heat treatment that activated the
l
-alanine- or glucose-stimulated germination systems. Although activation of the low-temperature germination system was accompanied by suppression of
l
-alanine-stimulated germination, it did not appear to be a modification of the
l
-alanine germination system.
Fermentation Process for Double-Stranded Ribonucleic Acid, an Interferon Inducer
Authors: Lago B. D. , Birnbaum J. , Demain A. L.
Published: December 2020

Double-stranded ribonucleic acid (ds-RNA) isolated from
Escherichia coli
infected with bacteriophage MS2 is a potent interferon inducer. High levels of ds-RNA are formed in nonpermissive cells infected with MU9, an amber coat protein mutant of MS2. This mutant has been used to develop a process for large-scale ds-RNA production. Preparation of quantities of MU9 lysate sufficient for ds-RNA production in fermentors is described. Over 300 μg of ds-RNA/ml can be accumulated after MU9 infection of cultures grown to high density in corn steep liquor medium. This is approximately 300 times the amount of ds-RNA made by MS2 infection of cells grown in tryptone medium. Maximum ds-RNA formation requires only 3 hr. The ds-RNA is stable and remains inside nonaerated cells for at least 17 hr.
Occurrence of Aflatoxins and Aflatoxin-Producing Strains of
Aspergillus
spp. in Soybeans
Authors: Bean George A. , Schillinger John A. , Klarman William L.
Published: December 2020

Above average rainfall in Maryland during August, September, and October 1971 resulted in heavy mold growth in soybeans while still in the field. Of 28 samples of soybean seed, aflatoxins were found in 14, 2 of which had been used in poultry feed. Aflatoxins were identified by thin-layer chromatography, spectrophotometry, and chicken embryo bioassay.
Aspergillus
spp. were isolated from 11 samples, and 5 of these isolates produced aflatoxins when grown in liquid culture.
Radiation Sterilization of Prototype Military Foods: Low-Temperature Irradiation of Codfish Cake, Corned Beef, and Pork Sausage
Authors: Anellis Abe , Berkowitz D. , Swantak W. , Strojan C.
Published: December 2020

“Screening” packs comprising 10 lots each of codfish cake, corned beef, and pork sausage, each lot containing about 10
6
spores of a different strain (five type A and five type B) of
Clostridium botulinum
per can, were irradiated at −30 ± 10 C with a series of increasing doses (20 replicate cans/dose) of
60
Co gamma rays. The cans were incubated for 3 months at 30 C and examined for swelling, toxin, and recoverable botulinal cells. Based on the latter criterion of spoilage, median lethal dose (LD
50
) and
D
values were estimated for each strain in each food. The most resistant strain in codfish cake, corned beef, and pork sausage was, respectively, 53B, 77A, and 41B. There was no clear-cut trend in the comparative order of resistance between the two antigenic types among the three foods. LD
50
values gave essentially the same order of resistances as the
D
values and may be used interchangeably with the latter for the 10 test organisms. “Clearance” packs consisting of the most resistant strain (about 10
7
spores/can) with its respective food were irradiated with a variety of doses at −30 ± 10 C, using 100 replicate cans/dose (about 10
9
spores/dose). These packs were incubated for 6 months at 30 C and assayed for the three types of spoilage. Based on recoverable cells, the experimental sterilizing doses (ESD) for codfish cake, corned beef, and pork sausage were 2.5< ESD ≤ 3.0, 2.0 < ESD ≤ 2.5, and 1.5 < ESD ≤ 2.0 Mrad, in that order. Assuming exponential spore death, the 12
D
values, or minimal radiation doses (MRD), were 3.24, 2.44, and 2.65 Mrad, respectively. Estimation of the MRD values by a method which assumes that spore death in the cans follows a normal distribution, yielded 3.09, 2.57, and 2.39 Mrad, respectively. Weibull analyis of the pooled 10-strain viable cell spoilage data of the screening packs for codfish cake or corned beef suggested that spore death in the cans follows a normal distribution yielded 3.09, 2.57, pooled data were not amenable to such analysis. Sublethal doses (0.5, 0.75 Mrad) increased the visible spoilage rate of corned beef over that of unirradiated controls. Apparently radiation-injured spores of
C. botulinum
were sensitized to the presence of food additives such as curing salts, NaCl, and spices.
Agar Diffusion Method for Negative Staining of Microbial Suspensions in Salt Solutions
Authors: Anderson Nan , Doane Frances W.
Published: December 2020

Microbial suspensions in a saline medium can be prepared for negative staining by a simple agar diffusion method that achieves a high degree of particle concentration.
Simple Method for Mass Production and Collection of Conidia from
Hemispora stellata
Authors: Sala F. J. , Burgos J.
Published: December 2020

A simple method is described for the mass production and collection of conidia from
Hemispora stellata
.
Polyelectrolyte Flocculation as an Aid to Recovery of Enteroviruses from Oysters
Authors: Kostenbader K. D. , Cliver D. O.
Published: December 2020

A simple and rapid method for recovering enteroviruses from oysters is described. A polycation sewage flocculant promoted cohesion of oyster solids and thereby aided separation of these from the viruses. Recovery of 80 to 100% of experimentally inoculated virus was achieved, and the suspension or extract obtained could be inoculated directly into tissue cultures or concentrated first for greater sensitivity.
New Medium for the Isolation and Enumeration of Pseudomonads
Authors: Solberg Myron , O'Leary Virginia S. , Riha William E.
Published: December 2020

A new medium containing 200 ppb of 2-hydroxy-2′,4,4′-trichlorodiphenyloxide (CH3565) and 10 ppm of cetyl-trimethyl-ammonium bromide (Cetrimide) in tryptic soy agar was developed and tested with 19 pure cultures of
Pseudomonas
, 20 microorganisms of other genera, commercially prepared ground beef, and laboratory-prepared inoculated ground beef. The new medium, CETCH agar, was compared with an antibiotic-containing medium. CETCH agar provided greater pseudomonad recoveries, a shorter incubation period prior to plate counting, and greater ease of preparation.
Effect of Shaking Speed on the Secretion of Enterotoxin B by
Staphylococcus aureus
Authors: Dietrich Glynn G. , Watson Robert J. , Silverman Gerald J.
Published: December 2020

The concentration of enterotoxin B secreted by four strains of
Staphylococcus aureus
was dependent upon the shaking speed. For the conditions established, each strain demonstrated an optimal shaking speed, and speeds in excess of the optimum resulted in decreased secretion of toxin. At the optimal shaking speed, maximum secretion occurred at 37 C. At 45 C, both growth and toxin secretion were absent. By using agar containing antienterotoxin B sera, studies with strain S-6 at optimal and suboptimal shaking speeds demonstrated that individual cells vary in their toxin-synthesizing ability and that the relative numbers of high and low producers change during the growth cycle. Although most of the toxin was secreted during the first 12 hr of growth, a portion was secreted during the subsequent 6 hr, even though growth as measured by colony-forming units per milliliter decreased and Klett units increased.
Similarity in Several Properties of Psychrophilic Bacteria Grown at Low and Moderate Temperatures
Authors: Frank Hilmer A. , Reid Ann , Santo Leatrice M. , Lum Norma A. , Sandler Sandra T.
Published: December 2020

Several properties of psychrophilic pseudomonads were studied with cells grown in batch culture in nutrient broth at 2 and 30 C. No differences were observed in the size, catalase activity, deoxyribonucleic acid, ribonucleic acid, or protein content of cells grown at either temperature. The importance of comparing physiologically similar cells is discussed.

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2,2-Dibromo-3-Nitrilopropionamide, a Compound with Slimicidal Activity
Authors: Wolf Paul A. , Sterner P. W.
Published: December 2020

Laboratory and field tests demonstrated that 2,2-dibromo-3-nitrilopropionamide was an effective slimicide for use in papermaking systems and cooling towers. It was also effective as a bactericide for soluble oil emulsions. Acute toxicity tests showed that its hydrolysis at
p
H 9 and 23 C yielded products that were relatively nonhazardous to fathead minnows.
Separation of Prodigiosenes and Identification as Prodigiosin Syntrophic Pigment from Mutant Pairs of
Serratia marcescens
Authors: Hearn Walter R. , Williams Robert H. , Burgus Roger C. , Williams Robert P.
Published: December 2020

Countercurrent distribution is capable of resolving mixtures of closely related prodigiosene pigments. Syntrophic pigment produced by several pairs of
Serratia marcescens
color mutants was identified as prodigiosin (2-methyl-3-amyl-6-methoxyprodigiosene) by countercurrent distribution, soda lime pyrolysis, and other techniques. The metabolic block of mutant strain H-462, derived from parent strain HY, was located between the blocks of mutant strains OF and WF, both derived from parent strain Nima.
Cellular Fatty Acid Composition of Selected
Pseudomonas
Species
Authors: Moss C. Wayne , Samuels S. B. , Weaver R. E.
Published: December 2020

The cellular fatty acid composition of 10 reference strains representing eight species of
Pseudomonas
was determined by gas-liquid chromatography. A variety of acids were detected in these organisms, including branched and straight-chained acids, cyclopropane, and hydroxy acids. Comparison of the presence and relative amounts of these acids among strains was useful for distinguishing various
Pseudomonas
species.
Bacteriological and Pathological Study of Animals Given Freund Adjuvant
Authors: Rigdon R. H. , Schadewald T.
Published: December 2020

Freund complete adjuvant, with allegedly “killed and dried”
Mycobacterium butyricum
added (intramuscularly in rabbits and intraperitoneally in mice), produced a local granulomatous lesion and frequently a similar lesion in the viscera. Acid-fast bacilli were present in these lesions, and in some animals
M. butyricum
was obtained in culture. When this culture was inoculated in mice, a similar lesion developed. Pathological lesions with similar acid-fast organisms also were observed by us in rabbits given Freund complete adjuvant by two other investigators.
Rapid, Direct Fluorescent-Antibody Method for the Detection of Salmonellae in Food and Feeds
Authors: Insalata N. F. , Mahnke C. W. , Dunlap W. G.
Published: December 2020

An improved immunofluorescent-antibody (FA) method for the detection of salmonellae in foods and feeds was developed. This FA method combines a rapid cultural phase and a serological phase that allow for propagation of salmonellae in a minimum time, employing the industrial 8-hr work day as a guide. Two hundred fifty naturally contaminated human food and animal feed samples, representing 647 trials, were tested by the FA method. A total of 18 different food and feed samples was used. The method used by the Association of Official Analytical Chemists (AOAC) for the detection of salmonellae was the control method. The percent agreement when comparing the FA slide method to the AOAC method ranged from 87.1 to 95.3%, depending upon the conjugated antisera used in comparative studies.
Microbial Metabolites with Insecticidal Properties
Authors: Cole M. , Rolinson G. N.
Published: December 2020

A screen of fungi for insecticidal activity revealed the ability of
Aspergillus versicolor
to make versimide, methyl-α-(methylsuccinimido)acrylate, a novel contact insecticide. The larvicidal activities of
Alternaria tenuis
and
Fusarium lateritium
were found to be due to tenuazonic acid and diacetoxyscirpenol, respectively. Thiolutin, cycloheximide, rubratoxin, patulin, trichothecin, an actinomycin, and scirpene-producing fungi also had insecticidal activity.
Pseudomonas
sp. ATCC 27330 with 17-Dehydrogenase Activity: a Contaminant in an Endocrine Laboratory
Authors: Kundsin Ruth B. , Underwood Richard H. , Rose Leslie I.
Published: December 2020

Steroidal conversion of testosterone to androstenedione was found mediated by a
Pseudomonas
species in a hospital endocrinology laboratory.
Microsystem for Collecting and Shipping Diagnostic Sera
Authors: Whittemore A. D. , Williams J. E.
Published: December 2020

A system is described for collecting, shipping, and storing serum samples using light-weight plastic microtest plates.
Inhibitory Effect of Glycerin on
Vibrio parahaemolyticus
and
Salmonella
Authors: Chun Doki , Seol Sung Yong , Tak Ryunbin , Park Cheong Kyu
Published: December 2020

In a study of the effect of glycerin in transport media on
Vibrio parahaemolyticus
and
Salmonella
, it was found that a concentration of 30% glycerin was highly inhibitory for
V. parahaemolyticus
and to a lesser degree for
Salmonella
. The incorporation of peptone or human feces in media did not reduce the inhibitory effect of glycerin. In media with 15% glycerin, viable counts of
V. parahaemolyticus
and
Salmonella
increased after 24 hr of incubation both in the presence and absence of feces. Due to the concurrent increase in the total bacterial count in the media containing feces, no enrichment effect was noted.
Sporulation of
Clostridium perfringens
Type A in Vacuum-Sealed Meats
Authors: Dework F. M.
Published: December 2020

Type A strains of
Clostridium perfringens
inoculated into vacuum-sealed packages of hamburger, roast beef, ground beef plus cream sauce, and turkey roll produced high levels of spores.
Enhancement of Murine Leukemia Virus Replication in Rat Tumor Cells Containing Rat C-Type Virus
Authors: Turner W. , Pearson G. , Bass Leslie R.
Published: December 2020

The yield of Maloney leukemia virus (MLV) from MLV-infected rat cells was shown to be enhanced in rat cells containing rat C-type virus. The MLV produced in these cells was shown to be identical to murine-derived MLV and devoid of properties related to rat C-type virus.
Differentiation Between
Mycobacterium kansasii
and
Mycobacterium marinum
by Gas-Liquid Chromatographic Analysis of Cellular Fatty Acids
Authors: Thoen Charles O. , Karlson Alfred G. , Ellefson Ralph D.
Published: December 2020

Comparison of the cellular fatty acids of 10 strains of
Mycobacterium marinum
and 35 strains of
Mycobacterium kansasii
revealed similarities within each species but differences between these two photochromogenic mycobacteria. A branched-chain fatty acid characteristic of
M. kansasii
was found in trace amounts in 2 of the 10 strains of
M. marinum
.
Comparative Studies on the Detoxification of Aflatoxins by Sodium Hypochlorite and Commercial Bleaches
Authors: Yang Charles Y.
Published: December 2020

Cultures of
Aspergillus flavus
and aflatoxins were destroyed by a commercial bleach (Clorox; active ingredient, NaOCl) or analytical reagent grade NaOCl at 7.0 × 10
-3
M NaOCl in 5 days. Addition of Clorox or NaOCl at 2.8 × 10
-3
M to the fungal growth medium prior to inoculation completely inhibited the fungal growth. Aflatoxin production was inversely proportional to the logarithm of NaOCl concentration and time of treatment. Clorox and NaOCl were equally effective on aflatoxins, but fungal cells were lysed more readily by Clorox than by NaOCl. Mycelia older than 8 days lysed more readily than younger ones. Most conidia survived concentrations below 1.4 × 10
-3
M. The lowest effective concentration for a 2-hr treatment was 8.8 × 10
-3
M which is well below the Clorox concentration recommended for routine laboratory decontamination of aflatoxins. Mice and rats injected with aflatoxins and aflatoxins incompletely destroyed by Clorox died within 72 hr and had typical liver and kidney damage caused by aflatoxins. However, animals injected with NaOCl or Clorox or Clorox-destroyed aflatoxin extracts survived and showed no obvious liver or kidney damage.
Anticapsin, a New Biologically Active Metabolite: Screening and Assay Procedures
Authors: Whitney J. G. , Funderburk Sandra S. , Westhead J. E. , Lively D. H. , Solenberg J. M. , Denney Jerry W.
Published: December 2020

In addition to its implication in the virulence of
Streptococcus pyogenes
, the hyaluronic acid capsule produced by this bacterium renders it resistant to infection by bacteriophage. A method employing
S. pyogenes
and a bacteriophage incorporated into an agar plate was devised as a screen to detect compounds that inhibit the formation of the hyaluronic acid capsule. Filter-paper discs saturated with experimental compounds were applied to the surface of test plates containing host plus phage and control plates of host only. After incubation, inhibition of capsule synthesis was indicated by the presence of clear zones where phage infection and lysis had occurred. Zones of growth inhibition on control plates represented classical antibacterial activity. During the testing of over 6,000 fermentation samples, anticapsin, a unique metabolite, was discovered. Modification of incubation temperature, thickness of agar layers, and host-phage input ratios resulted in a quantitative assay method having a dose-response range of 4 to 160 μg of anticapsin.
Convenient Assay for Staphylococcal Nuclease by the Metachromatic Well-Agar-Diffusion Technique
Authors: Lachica R. V. F. , Hoeprich P. D. , Franti C. E.
Published: December 2020

The metachromatic agar-diffusion (MAD) microslide technique was adapted for quantitative assay for staphylococcal thermonuclease in heterogeneous systems, such as milk and broth. When an enzyme-containing solution was placed in a well cut in the agar, a bright pink halo was obtained. The diameter of the pink zone of hydrolysis was related to time and temperature of incubation and to nuclease concentration. Concentrations of nuclease as low as 0.005 μg/ml and as high as 2.0 μg/ml were conveniently determined after 3 hr at 37 C.