bluuebunny/crossref_metadata_2025 huggingface dataset:
Practical Method for Isolation of Anaerobic Bacteria in the Clinical Laboratory
Authors: Martin William J.
Published: December 2020

An inexpensive but practical and simple method is described for providing an environment suitable for the maintenance and survival of clinically significant anaerobic bacteria, consistent with the needs of a large-volume laboratory. This modification of the GasPak procedure is based on two concepts. One involved the storage of “freshly prepared” plating medium under a constant stream of carbon dioxide. The other concept was to use an anaerobe jar, continuously flushed with oxygen-free carbon dioxide, as a “holding receptacle” for the inoculated media Experience with this modification has shown that the number of isolations of anaerobic bacteria from clinical material can be increased significantly.
Evaluation of Methods Used to Purify Acid-Extracted Group A Streptococcal M Protein
Authors: Phillips Lawrence S. , Pine Leo
Published: December 2020

The literature includes descriptions of both acid-soluble and acid-insoluble M protein in the preparation of “hot acid-extracted group A streptococcal M protein.” We present evidence for the contamination of crude type 1 acid-insoluble M protein. The purification of preparations of crude and partially purified acid-soluble type 1 and type 12 M protein is described. Our quantitative criteria for purification were recovery of M precipitin activity, improvement in specific activity, and removal of carbohydrate. Exclusion of nucleic acid is also discussed. Greater purification in a single passage was found with a carboxymethylcellulose column (with acidic elution) than with hydroxyapatite, diethylaminoethyl-Sephadex, or carboxymethyl-cellulose (with neutral elution) columns or with ammonium sulfate fractional precipitation. Carboxymethylcellulose with acidic elution was found to be a satisfactory standard laboratory procedure for the preparation of purified acid-extracted (acid-soluble) group A streptococcal M protein.
Production of
l
-Arginine by Arginine Hydroxamate-Resistant Mutants of
Bacillus subtilis
Authors: Kisumi Masahiko , Kato Jyoji , Sugiura Masaki , Chibata Ichiro
Published: December 2020

l
-Arginine hydroxamate inhibited the growth of various bacteria, and the inhibition was readily reversed by arginine.
l
-Arginine hydroxamate (10
−3
m
) completely inhibited the growth of
Bacillus subtilis
. This inhibitory effect was prevented by 2.5 × 10
−4
m
l
-arginine, which was the most effective of all the natural amino acids in reversing the inhibition.
l
-Arginine hydroxamate-resistant mutants of
Bacillus subtilis
were isolated and found to excrete
l
-arginine in relatively high yields. One of the mutants, strain AHr-5, produced 4.5 mg of
l
-arginine per ml in shaken culture in 3 days.
Aerosol Survival of
Pasteurella tularensis
and the Influence of Relative Humidity
Authors: Cox C. S. , Goldberg L. J.
Published: December 2020

The aerosol survival in air was determined for
Pasteurella tularensis
live vaccine strain (LVS) as a function of relative humidity (RH). Three different preparations of bacteria were used: (i) liquid suspension of
P. tularensis
LVS in spent culture medium; (ii) powders of
P. tularensis
LVS freeze-dried in spent culture fluid; (iii)
P. tularensis
LVS freeze-dried in spent culture fluid and then reconstituted with distilled water and disseminated as a liquid suspension. Preparation (i) gave greatest survival at high RH and lowest survival at intermediate RH. Preparation (ii), in contrast, gave greatest survival at low RH and minimum survival at 81% RH. Preparation (iii) was the same as preparation (i), i.e., the process of freeze-drying and reconstituting with distilled water before aerosol formation had little or no effect upon aerosol survival as a function of RH. Hence, control of aerosol survival appears to be through the water content of
P. tularensis
LVS at the moment of aerosol generation rather than the water content of the bacteria in the aerosol phase.
Mouse Potency Assay for Western Equine Encephalomyelitis Vaccines
Authors: Robinson David M. , Berman Sanford , Lowenthal Joseph P.
Published: December 2020

A potency assay for Western equine encephalomyelitis vaccine was developed which utilized mice as the test animal instead of guinea pigs or hamsters. By immunizing several groups of mice with dilutions of the vaccine and challenging them intracerebrally with virulent virus, it was possible to determine mathematically a dose of vaccine capable of protecting 50% of the animals (ED
50
). When log dilutions of virulent virus were used to challenge mice which were immunized with dilutions of the vaccine, there was no difference among the ED
50
values for the dilutions of challenge virus. In a direct comparison of ED
50
values determined from the immunization of mice and those determined from the immunization of guinea pigs, there were no differences in the rankings of the vaccines.
Numerical Diagnostic Key for the Identification of
Enterobacteriaceae
Authors: Baer Herman , Washington Louis
Published: December 2020

A numerical diagnostic key for enteric organisms is described which permits the identification of typical strains and of biochemical variants with high accuracy. Unknown strains are inoculated into a basic set of five media which permit the testing of eight biochemical reactions. The positive reactions are assigned points, and the score of a strain is added up, after which the identification of the strain is obtained from a table. In many instances, the final identification is obtained with this set of biochemical tests; and, in other instances, a small number of additional tests are required to distinguish between organisms giving the same score in the basic set of biochemical tests. The key permits an accurate, rapid, and economical differentiation of the typical and the more common atypical biotypes of enteric organisms in the clinical laboratory.
Microbial Flora of Pacific Oysters (
Crassostrea gigas
) Subjected to Ultraviolet-Irradiated Seawater
Authors: Vasconcelos G. J. , Lee J. S.
Published: December 2020

The ability of oysters to purge themselves of microbial contaminants was investigated by identifying the microorganisms retained by oysters after they have been subjected to ultraviolet (UV) light-treated seawater. A UV intensity of 960 μw per min per cm
2
reduced the microbial count of seawater from 263 to 13 per ml. The coliform multitube test (MPN) was reduced from a high of 17 to <0.18 per 100 ml. Over 75% of the microorganisms found in treated seawater were
Acinetobacter/Moraxella, Vibrio/Pseudomonas
type II, and
Flavobacterium/Cytophaga
. With the exception of coliforms, the microbial composition of oysters subjected to UV-treated seawater remained at levels comparable to the control oysters held in untreated seawater. Total counts ranged between 10
3
and 10
5
/g. The microorganism most frequently encountered were
Flavobacterium/Cytophaga, Vibrio/Pseudomonas
type II,
Pseudomonas
type III or IV,
Acinetobacter/Moraxella
, gram-positive cocci and
Bacillus
. Together they comprised over 90% of the flora. Coagulase-positive, deoxyribonuclease-positive, and beta-hemolytic cocci were found in some samples, as were
V. parahaemolyticus, V. aliginolyticus
, and
Aeromonas
species.
Reproducible Topical Staphylococcal Infection in Rats
Authors: Goldschmidt Faith
Published: December 2020

A topical infection model for the study of the effectiveness of antimicrobials was developed. Animals were laparotomized, sutured with braided silk, and inoculated with a strain of
Staphylococcus aureus
. The test organism was phage typed, and its antibiotic spectrum was determined. Concentrations of bacteria from 5 × 10
4
to 10
8
cells per incision produced large body wall stitch abscesses with occasional drainage through the skin. This laparotomy infection is readily reproducible and can be used for evaluation of the ability of topical antimicrobials to prevent
S. aureus
stitch abscesses.
Characterization of the Growth of Herpes Simplex Virus in Human Lymphoid Cells
Authors: Mizrahi A. , Mitchen J. R. , Von Heyden H. W. , Minowada J. , Moore G. E.
Published: December 2020

Herpes simplex virus was grown in a 6-liter suspended culture of an atypical permanent human lymphoid cell line, Roswell Park Memorial Institute no. 8226. The kinetics of virus replication were determined by counting viruses by electron microscopy, plaque formation, and tissue culture infectivity. Deoxyribonucleic acid-dependent deoxyribonucleic acid polymerase activity was determined during the course of infection. Electron microscopy studies substantiated the kinetics of the virus infection in lymphoid cells.
Metachromatic Agar-Diffusion Microslide Technique for Detecting Staphylococcal Nuclease in Foods
Authors: Lachica R. V. F. , Hoeprich P. D. , Genigeorgis C.
Published: December 2020

The metachromatic agar-diffusion (MAD) microslide technique was shown to detect nanogram quantities of staphylococcal thermonuclease in various foods without prior extraction, purification, or concentration.
Automated Slide Staining Machine
Authors: Drew W. Lawrence , Pedersen Anders N. , Roy Jacques J.
Published: December 2020

A machine is described which can perform the Gram stain. Comparison of slides stained by machine versus hand revealed no difference in reproducibility or accuracy. In addition to providing clean, dry, uniformly stained slides, the machine saves 24 sec per slide when compared with a hand staining technique.
Preliminary Observations on the Uptake of Poliovirus by West Coast Shore Crabs
Authors: DiGirolamo Rudolph , Wiczynski Leokadia , Daley Michael , Miranda Florencio
Published: December 2020

West Coast shore crabs (
Pachygrapsus
sp. and
Hemigrapsus
sp.), when in seawater contaminated with poliovirus or allowed to feed on virus-contaminated mussels (
Mytilus californianus
), were found to accumulate high titers of virus.
Effects on Turkey Poults of Rations Containing Corn Invaded by
Fusarium tricinctum
(Cda.) Sny. & Hans
Authors: Christensen C. M. , Meronuck R. A. , Nelson G. H. , Behrens J. C.
Published: December 2020

Consumption of an otherwise balanced ration containing 1% of corn invaded by
Fusarium tricinctum
isolate 2061-C resulted in the death of 13% of turkey poults within 35 days, in decreased feed efficiency and weight gain, and moderate development of bilateral necrotic lesions at angles of the mouth, especially in those that succumbed. Consumption of a ration with 2% of corn invaded by
F. tricinctum
resulted in death of 60 to 83% of the birds, in greatly reduced growth and feed efficiency in the survivors, and in development of severe mouth lesions. Consumption of rations containing 5, 10, and 20% of corn invaded by the fungus resulted in death of all birds in 5 to 15 days.
New Mycotoxin, Trichotoxin A, from
Trichoderma viride
Isolated from Southern Leaf Blight-Infected Corn
Authors: Hou C. T. , Ciegler A. , Hesseltine C. W.
Published: December 2020

A new mycotoxin, trichotoxin A, was found in a solvent extract of the mycelium of
Trichoderma viride
isolated from corn infected with southern leaf blight. Trichotoxin A is a cyclic peptide with the following amino acid composition: (gluN)
2
, (glu)
1
, (pro)
2
, (gly)
1
, (ala)
3
, (leu)
3
, (2-methyl alanine)
1
.
Automatic Device for the Trypsinization of Animal Tissues
Authors: Shipman Charles , Smith David F.
Published: December 2020

Using a simple glass device, enzymatically released monodisperse cells can be separated and isolated from tissue fragments by means of a discontinuous fluid velocity gradient.
Sensitivity of the
14
CO
2
Radiometric Method for Bacterial Detection
Authors: Waters John R.
Published: December 2020

Decimal serial dilutions of eight common bacterial species were prepared, and the detection times were determined by measuring the
14
CO
2
metabolized from the
14
C-labeled glucose substrate. The detection time was proportional to the logarithm of the initial inoculum, and high sensitivity, down to 1 colonyforming unit, was demonstrated.
Effect on Young Swine of Consumption of Rations Containing Corn Invaded by
Fusarium roseum
Authors: Christensen C. M. , Mirocha C. J. , Nelson G. H. , Quast J. F.
Published: December 2020

Both male and female pigs given a ration containing corn invaded by
Fusarium roseum
, in amounts sufficient to provide 500 to 600 ppm of F-2, for the first 64 days of the test and which for another 60 days were given a commercial pig ration were much lower in weight than the controls which were given a commercial pig ration throughout. In relation to the weight of the animals, in the pigs receiving the ration containing F-2, the weight of the uterine horn of the gilts was much greater and the weight of the testes of the males was much less than the weight of the same organs of the controls.
Procedure for Isolation and Enumeration of
Vibrio parahaemolyticus
,
Authors: Vanderzant C. , Nickelson R.
Published: December 2020

An evaluation of criteria used in the identification of
Vibrio parahaemolyticus
showed that cultural responses varied with respect to growth in broth with 10% NaCl, type of hemolysis, reactions in triple sugar-iron-agar, and serological reactions. With few or no exceptions, cultures were positive for cytochrome oxidase, utilized glucose fermentatively, were sensitive to pteridine (0/129) and novobiocin, and failed to grow in Trypticase soy broth (TSB) without NaCl. A procedure employing a direct plating technique, with or without prior enrichment, was designed for the isolation and enumeration of
V. parahaemolyticus
. The plating medium consisted of 2.0% peptone, 0.2% yeast extract, 1.0% corn starch, 7% NaCl, and 1.5% agar, with the
p
H adjusted to 8.0. The enrichment broth was TSB with 7% NaCl. Dilutions of food homogenates were either spread directly on the plates or inoculated into enrichment broth. TSB enrichments were incubated at 42 C for 18 hr. A loopful of the TSB tubes then was streaked onto the direct plating medium. Incubation of plates was at 42 C for 24 to 48 hr. Smooth, white to creamy, circular, amylase-positive colonies were then picked as suspect
V. parahaemolyticus
. Confirmation of gram-negative, fermentative, oxidase-positive, pleomorphic rods sensitive to pteridine 0/129 was made by a fluorescent-antibody technique. With this procedure, a satisfactory quantitative recovery of known
V. parahaemolyticus
from inoculated seafoods was made possible.
V. parahaemolyticus
was nto isolated from other salted foods.
Survival of
Vibrio parahaemolyticus
in Shrimp Tissue Under Various Environmental Conditions
Authors: Vanderzant C. , Nickelson R.
Published: December 2020

Vibrio parahaemolyticus
culture O from Gulf Coast shrimp was inoculated into whole shrimp and shrimp homogenate to determine its survival at various temperatures and
p
H values. Although large decreases in viable population occurred during storage for 2 days at 10 to -18 C, survivors were present even after 8 days. No significant differences were observed in the population changes of inoculated whole shrimp as compared with shrimp homogenates. Low populations (5 × 10
2
per ml) of
V. parahaemolyticus
were destroyed by heating shrimp homogenates at 60, 80, and 100 C for 1 min. With larger populations (2 × 10
5
per ml), some survivors were present after heating at 60 and 80 C for 15 min. None survived 1 min at 100 C.
V. parahaemolyticus
was very sensitive to
p
H values below 6.0. Cells survived for several hours in the contents of the porcine gastrointestinal tract.
Evaluation of the In Vitro Activity of Tobramycin as Compared with That of Gentamicin Sulfate
Authors: Traub Walter H. , Raymond Ella A.
Published: December 2020

The in vitro activity of tobramycin was quantitatively compared with that of gentamicin sulfate against 195 bacterial isolates from clinical material. Tobramycin was found to be twice as active as gentamicin against isolates of
Pseudomonas aeruginosa
. Conversely, gentamicin proved fourfold more active than tobramycin against isolates of
Serratia marcescens
. Both drugs were of comparable activity against isolates of
Staphylococcus aureus
and the majority of the enterobacterial isolates other than
S. marcescens
. On the basis of the obtained data, the following criteria are proposed for the interpretation of diffusion susceptibility tests with 10-μg discs of gentamicin and tobramycin.
Enterobacteriaceae
and isolates of
S. aureus
are designated as susceptible to gentamicin and tobramycin if the zones of inhibition measure 15 mm or more in diameter; zones of 14 mm or less are indicative of resistance.
Pseudomonadaceae
are interpreted as sensitive to tobramycin and gentamicin if the inhibition zones measure at least 15 and 12 mm in diameter, respectively.
Variation in the Toxicity of Arsenic Compounds to Microorganisms and the Suppression of the Inhibitory Effects by Phosphate
Authors: Da Costa E. W. B.
Published: December 2020

The toxicity of potassium arsenate, as measured by retardation or inhibition of growth on solid nutrient media, showed wide variation among different fungi but was consistently reduced by the addition of large amounts of potassium phosphate, with both arsenic-sensitive and arsenic-tolerant fungi.
Poria monticola
was completely inhibited by 0.0025 M arsenate but was progressively less inhibited as the phosphate content of the medium increased and grew slowly at 0.04 M arsenate when 0.16 M KH
2
PO
4
was added.
Cladosporium herbarum
showed 36% reduction in growth at 0.08 M arsenate in a low-phosphate medium, but when 0.01 M KH
2
PO
4
was added, arsenate concentrations up to 0.64 M (at which the medium contains 4.8% As) caused no reduction in growth rate. Addition of phosphate also reduced the toxicity of potassium arsenite but not that of dimethyl sodium arsonate (sodium cacodylate). The counteracting effect of phosphate on arsenate toxicity was found to occur with every one of a wide variety of microorganisms tested. The author interprets the results as supporting the thesis that the fungitoxicity of arsenate is due to its competitive interference with phosphorus in oxidative phosphorylation and not to a reaction with the —SH groups of essential proteins. The latter mechanism is, however, probably operative with dimethyl sodium arsonate. The practical implications of the counter-inhibition phenomenon in laboratory investigations and standard tests of arsenical fungicides, in biochemical research, and in the commercial use of arsenical biocides are set out.
Effects of Carbohydrates in Growth Medium on Agglutination of Several Species of
Salmonella
with Polyvalent H Antiserum
Authors: Banwart George J. , Kreitzer Madeleine J.
Published: December 2020

The effect of various carbohydrates in the growth medium on agglutination of salmonellae with polyvalent H antiserum was studied. There appeared to be a relationship between fermentation of the carbohydrate by the organism and resultant agglutination with the antiserum. It is recommended that the tube test for flagellar antigens be allowed to remain in a water bath for 2 hr before the final observation is made. Sorbitol, dulcitol, mannose, maltose, rhamnose, or trehalose, when included in the growth medium for
Salmonella
, yielded high percentages of positive agglutinations with all conditions of the experiment.
Prophage Induction in Lysogenic
Escherichia coli
with
N
-Nitroso Compounds and Derivatives
Authors: Heinemann Bernard
Published: December 2020

Prophage induction in lysogenic
Escherichia coli
W1709 (ι) was determined for 29
N
-nitroso compounds, 13 of their denitrosated derivatives, and 7 hydroxylamino and hydrazino analogues of nitrosamines. Minimal inducing concentrations of 0.1 to 2.0 μg/ml were demonstrated for eight nitrosamidines, and concentrations of 0.5 to 25.0 μg/ml were shown for six nitrosamides. Weak inducing activities were found with
N,N
-diethylhydroxylamine oxalate and
N
-methyl-
N
-phenylhydrazine sulfate, derivatives of inactive
N
-nitrosodiethylamine and
N
-nitrosomethylphenylamine, respectively. Inactive compounds including
N
-methyl-
N
-nitroso-
p
-toluenesulfonamide, 11 nitrosamines, 3
N, N
′-dialkyl substituted-
N
-nitrosoureas, 13 denitrosated derivatives, and 5 hydroxylamino and hydrazino analogues of nitrosamines are listed. Since 7 of the 14 prophage-inducing nitrosamidines and nitrosamides reported thus far have carcinostatic activity in rodent tumor systems, it is concluded that the induction test may provide a useful screen for the detection of potential antitumor compounds. The induction test may also be useful for the detection of responsive
N
-nitroso compounds which may be potential toxicological hazards in the environment since, of the six active nitrosamides, five have already been reported to produce mutagenic and carcinogenic effects, four produce chromosomedamaging effects, and two produce teratogenic effects. Use of the prophage induction system for detection of biologically active intermediates formed by
N
-nitroso compounds under physiological conditions is considered.
Epidemiological Differentiation of
Serratia marcescens:
Typing by Bacteriocin Sensitivity
Authors: Farmer J. J.
Published: December 2020

Strains of
Serratia marcescens
were compared and differentiated by a new method. Bacteriocin lysates were prepared from mitomycin-induced
S. marcescens
and added to lawns of test strains. From 100 bacteriocin producers, 12 were chosen with the aid of computer analysis as the most useful in differentiation. Uniform drops of the 12 standard bacteriocins were added simultaneously with a bacteriocin-bacteriophage dropper to each strain to be typed. All 93 strains of
S. marcescens
tested were typable and were differentiated into 79 different sensitivity patterns. One pattern had three strains, 12 patterns had two strains each, and 66 patterns had only one strain. The bacteriocins also inhibited
Shigella, Klebsiella
, and
Enterobacter
, but no other
Enterobacteriaceae
. Bacteriocin sensitivity was less stable as an epidemiological marker than bacteriocin production. Several colonial mutants had sensitivity patterns different from the wild types, but most mutants were identical. In three different instances when cross-infection had been shown by other methods, bacteriocin sensitivity also gave the correct epidemiological results. Until the significance and frequency of genetic variations are known, a more stable epidemiological technique should be used in conjunction with bacteriocin sensitivity.
Rapid Extraction Method with Pronase B for Grouping Beta-Hemolytic Streptococci
Authors: Ederer Grace Mary , Herrmann Mary M. , Bruce Robert , Matsen John M. , Chapman S. Stephen
Published: December 2020

The enzyme, Pronase B, was used to extract the C carbohydrates of betahemolytic streptococci for serological grouping. Reference strains of streptococci, groups A through N, were accurately grouped by using this extraction method. Of the beta-hemolytic streptococci isolated from patients' cultures, 1,197 were classified as either group A or not group A by this method. There was 100% correlation with the reference Lancefield method. In contrast, false reactions occurred with the presumptive bacitracin disc method in 4.1% of the group A and 12.7% of the non-group A cultures. The Pronase method proved simple, accurate, and readily adaptable to the clinical laboratory routine.
Mode of Transmission of
Pseudomonas aeruginosa
in a Burn Unit and an Intensive Care Unit in a General Hospital
Authors: Kominos Spyros D. , Copeland Charles E. , Grosiak Barbara
Published: December 2020

The transmission of
Pseudomonas aeruginosa
was studied in the burn unit and the intensive care unit of a 650-bed hospital. There was a tendency among patients in the burn unit to yield more than one type of
P. aeruginosa
, and several patients shared the same types at a particular point in time, suggesting cross-contamination among patients. Similar observations were made in the intensive care unit. Cultures from the hands of nurses caring for these patients yielded the same types of
P. aeruginosa
, suggesting the direct handling of patients by the nursing personnel to be the principal mode of transmission.
Use of Shake Cultures in a Semisolid Thioglycolate Medium for Differentiating Staphylococci from Micrococci
Authors: Evans James B. , Kloos W. E.
Published: December 2020

The standard diagnostic test for differentiating staphylococci from micrococci is based on the ability of the former to produce acid anaerobically in a glucose-containing growth medium. This test has been modified to provide greater convenience, easier interpretation of results, and better correlation with deoxyribonucleic acid (DNA) base composition. In the modified test, shake cultures in Brewer's fluid thioglycolate medium with 0.3% agar added are observed for growth in the anaerobic zone of the tubes. This test was applied to 125 strains of staphylococci and micrococci, and all except two strains gave results that were consistent with other criteria. Of particular interest were eight strains of
Micrococcus saprophyticus
and three strains of
M. lactis
that have a DNA composition of 30 to 37% guanine plus cytosine (GC). All 11 of these cultures produced anaerobic growth and thus would be classified as staphylococci. Strains of
M. lactis
that have a high GC content in their DNA grew only aerobically. Some cultures of staphylococci produced characteristic band patterns of anaerobic growth and other cultures produced only a few anaerobic colonies from an inoculum of 10
6
to 10
7
cells. These observations suggest some interesting genetic and metabolic capabilities in such cultures.
Fermentation of Isolated Pectin and Pectin from Intact Forages by Pure Cultures of Rumen Bacteria
Authors: Gradel Catherine M. , Dehority B. A.
Published: December 2020

Studies on the rate and extent of galacturonic acid and isolated pectin digestion were carried out with nine strains of rumen bacteria (
Butyrivibrio fibrisolvens
H10b and D16f,
Bacteroides ruminicola
23 and D31d,
Lachnospira multiparus
D15d,
Peptostreptococcus
sp. D43e,
B. succinogenes
A3c,
Ruminococcus flavefaciens
B34b, and
R. albus
7). Only three strains, 23, D16f, and D31d, utilized galacturonic acid as a sole energy source, whereas all strains except A3c and H10b degraded (solubilized) and utilized purified pectin. Nutrient composition of the basal medium and separate sterilization of the substrate affected the rate and extent of fermentation for both substrates. Pectin degradation and utilization were measured with two maturity stages each of intact bromegrass and alfalfa. For bromegrass I, all strains tested (B34b, 23, D16f, D31d, D15d, and D43e) degraded a considerable amount of pectin and, with the exception of B34b, utilized most of what was degraded. Similar, but lower, results were obtained with bromegrass II, except for the two strains of
B. ruminicola
, 23 and D31d, which were unable to degrade and utilize pectin from this forage. All strains were able to degrade and utilize pectin from both maturity stages of alfalfa; however, values were considerably lower for strains 23 and D31d. Synergism studies, in which a limited utilizing strain, B34b, was combined with the limited degrading strain, D31d, resulted in a slight increase in degradation and a very marked increase in utilization of the pectin in all four forages. Similar results were obtained on both alfalfa substrates with a combination of strains B34b and D16f; however, no increases were observed with this combination on bromegrass.
Solid-Phase Radioimmunoassay of Total and Influenza-Specific Immunoglobulin G
Authors: Daugharty Harry , Warfield Donna T. , Davis Marianne L.
Published: December 2020

An antigen-antibody system of polystyrene tubes coated with immunoglobulin antibody was used for quantitating immunoglobulins. A similar radioimmunoassay method was adapted for a viral antigen-antibody system. The viral system can be used for quantitating viruses and for measuring virus-specific antibodies by reacting with
125
iodine-labeled anti-immunoglobulin G (IgG). Optimal conditions for coating the solid phase, specificity of the immune reaction, and other kinetics and sensitivities of the assay method were investigated. Comparison of direct and indirect methods of assaying for immunoglobulins or viral antibody indicates that the indirect method is more sensitive and can quantitate a minimum of 0.037 μg of IgG per ml. Results of solid-phase radioimmunoassay for influenza antibody correlate well with hemagglutinin antibody titers but not with complement-fixing antibody titers. Radioimmunoassay results for influenza antibody by solid phase are likewise in agreement with results by the carrier precipitate radioimmunoassay method. The simplicity, reproducibility, and versatility of the solid-phase procedure make it diagnostically useful.
Co-Infection of Mouse Spleen Cells with Murine Sarcoma Virus and Guaroa Virus
Authors: Woods Wilna A. , Turner Willie , Chirigos Michael A.
Published: December 2020

Enhancement of tumor induction by oncornaviruses through a dual viral infection has been described by several investigators. The mechanism(s) of this enhancement has not as yet been determined. By using a murine sarcoma virus and a Bunyawera group arbovirus (Guaroa virus) in an in vitro system, evidence was obtained for enhancement of the oncogenic potential of the viruses by genetic interaction with the nononcogenic virus as well as the production of increased amounts of the oncogenic virus. These results confirm and extend similar responses obtained in in vivo systems.
Some Slime-Forming Heterofermentative Species of the Genus
Lactobacillus
Authors: Sharpe M. Elisabeth , Garvie Ellen I. , Tilbury R. H.
Published: December 2020

Lactobacillus coprophilus
subsp.
confusus
(NCDO 1586) and 18 other strains of slime-forming heterofermentative lactobacilli obtained from diverse sources are considered to form a new species on the basis of their physiological characteristics and similarities of their pyruvate reductases and lactate dehydrogenases. It is suggested that these strains should be named
Lactobacillus confusus
(Holzapfel & Kandler) comb. nov. (
L. coprophilus
subsp.
confusus
Holzapfel & Kandler), reasons being given. The type strain is NCDO 1586 (NCIB 9311, ATCC 10881). Strains of
Lactobacillus vermiforme
and
Lactobacillus viridescens
also form slime. However,
L. vermiforme
was readily separated from the other two by the criteria used. Although physiological characteristics separated
L. viridescens
from
L. confusus
, a relationship between these two species and also between them and the leuconostocs was indicated by the properties of the pyruvate reductases and lactate dehydrogenases. The slime produced by all species was found to be a glucan, probably a dextran, containing primarily α-1-6-glycosidic linkages.
Chromogenicity of
Streptomyces
Authors: Arai Tadashi , Mikami Yuzuru
Published: December 2020

A simplified technique to detect polyphenol oxidase and melanin formation by
Streptomyces
culture filtrates was developed. The procedure involves the direct assay of pigment formation by the culture filtrate with 3-(3,4-dihydroxyphenyl)-L-alanine (L-dopa) as a substrate. Among cultures of the International Streptomyces Project, 34 failed to produce a diffusible dark brown pigment on peptone-yeast extract-iron-agar and synthetic tyrosine-agar and gave a negative reaction to the melanin formation test. Sixteen cultures produced a diffusible dark brown pigment on both peptone-yeast extract-iron-agar and synthetic tyrosine-agar and gave positive reactions to the test with either L-tyrosine or L-dopa as substrate. Twenty-one cultures produced a diffusible dark brown pigment on peptone-yeast extract-iron-agar, but failed to do so on synthetic tyrosine-agar. Most of these cultures gave a positive reaction to the test when L-dopa was used as the substrate. The correlation between chromogenicity on complex organic media and melanin formation was more clearly established with L-dopa as substrate than with synthetic tyrosine-agar in the present test. The melanin formation test by the present technique, instead of chromogenicity on complex organic media, is recommended as a key feature for the classification of
Streptomyces
.
Inhibition of the Indole Test Reaction by Sodium Nitrite
Authors: Smith Rodney F. , Rogers Robert R. , Bettge Carol L.
Published: December 2020

Sodium nitrite formed by nitrate reduction produced a false-negative reaction in the detection of indole formation when both tests were conducted in one medium.
Medium-Scale Production and Purification of Ochratoxin A, a Metabolite of
Aspergillus ochraceus
Authors: Davis N. D. , Sansing G. A. , Ellenburg T. V. , Diener U. L.
Published: December 2020

The preparation of crystalline ochratoxin A from
Aspergillus ochraceus
nutrient solution is described. Methods are adaptable to large-scale fermentations.
Hemolytic Interaction of Newcastle Disease Virus and Chicken Erythrocytes. I. Quantitative Comparison Procedure
Authors: Bratt Michael A. , Clavell Luis A.
Published: December 2020

The extent to which erythrocytes are hemolyzed by Newcastle disease virus is a function of the relative concentrations of both virus and erythrocytes. Under proper conditions, the interaction of a single virus particle with an erythrocyte is sufficient to cause lysis. The extent of hemolysis is directly proportional to virus concentration only when the virus-erythrocyte ratio is very low. At the higher virus-erythrocyte ratios usually employed in hemolysis experiments, the extent of hemolysis is proportional to the logarithm of the virus concentration. Thus, quantitative comparisons of hemolytic activities of different virus preparations cannot be made by directly comparing the extent of hemolysis. Relative hemolytic activities must be determined by comparing virus concentrations which yield equivalent amounts of hemolysis (the quantitative comparison procedure).
Hemolytic Interaction of Newcastle Disease Virus and Chicken Erythrocytes. II. Determining Factors
Authors: Clavell Luis A. , Bratt Michael A.
Published: December 2020

Standard procedures have been described for measuring paramyxovirus-induced hemolysis. The choice of these procedures is based on the analysis of the behavior of eight different strains of Newcastle disease virus. Significant strain-specific differences in hemolytic activity have been found. The presence of at least two kinds of inhibitors of hemolysis in virus preparations necessitates the use of purified virus when comparisons of hemolytic activities are to be made. In addition, it has been stressed that both hemagglutination titers and hemolysis determinations provide only relative values. Thus, quantitative comparisons can be made only with results obtained on the same day and with the same erythrocyte preparation.
Modified Hemagglutination-Inhibition Test for Rubella Employing Human Group O Erythrocytes
Authors: Schmidt Nathalie J. , Dennis Juanita
Published: December 2020

A hemagglutination-inhibition (HI) test for rubella is described which utilizes human group O, rather than 1-day-old chick, erythrocytes. The test was found to be as sensitive and reproducible for detection of rubella antibody as HI tests employing chick erythrocytes. Advantages to the use of human erythrocytes are (i) they are more available, (ii) it is unnecessary to absorb natural agglutinins from human test sera, and (iii) heparin-MnCl
2
-treated sera do not agglutinate human erythrocytes, as is sometimes the case with chick erythrocytes. Factors influencing the reliability of the test are discussed.
Effect of NO
2
on Airborne Venezuelan Equine Encephalomyelitis Virus
Authors: Ehrlich Richard , Miller Sol
Published: December 2020

Studies were conducted to determine the effect of nitrogen dioxide (NO
2
) on aerosol survival and biological decay rate of Venezulean equine encephalomyelitis (VEE) virus and spores of
Bacillus subtilis
var.
niger
. The NO
2
concentrations used in the experiments were 0.5, 5, and 10 ppm at 24 C and 85% RH. The survival of airborne VEE virus disseminated as particles 1 to 5 μm in diameter was significantly influenced by the presence of 5 ppm of NO
2
. At this concentration, the biological decay rate increased threefold and the aerosol recovery and aerosol survival of the VEE virus were significantly lower than at 0.5 ppm or in the absence of NO
2
. Airborne spores of
B. subtilis
were not significantly affected by as much as 10 ppm of NO
2
.
Evaluation of the Sterifil Lysis-Filtration Blood Culture System
Authors: Farmer Silas G. , Komorowski Richard A.
Published: December 2020

This paper describes the comparison of the Sterifil lysis-filtration (SLF) blood culture procedure with a standard Trypticase soy broth (TSB) technique. The lysing solutions employed in the SLF system, Triton X-100 (alkyl phenoxy polyethoxy ethanol) and sodium carbonate, were deleterious to most bacteria commonly encountered in bacteremia except staphylococci and enterococci.
Candida
was not adversely affected. There was a positive correlation between the tolerance of the microbial isolants to the lysing solutions and their recovery by the SLF technique. A total of 3,554 cultures were run in parallel and 398 isolants were obtained. Of 201 gram-positive isolants, 135 were recovered by both techniques, 43 were detected by the TSB technique only, and 23 were recovered only with the SLF method. In sharp contrast, of 168 gram-negative isolants, 28 were recovered in common, 130 were isolated only by TSB, and 10 were recovered only with the SLF method. The SLF method detected all cases of candidemia detected by the TSB method plus an additional 12 for a total of 29 cases. The SLF method, as currently described, is generally too toxic to bacteria for routine use in a clinical laboratory.
Semiautomated Method for Microbiological Vitamin Assays
Authors: Berg T. M. , Behagel H. A.
Published: December 2020

A semiautomated method for microbiological vitamin assays is described, which includes separate automated systems for the preparation of the cultures and for the measurement of turbidity. In the dilution and dosage unit based on the continuous-flow principle, vitamin samples were diluted to two different dose levels at a rate of 40 per hr, mixed with the inoculated test broth, and dispensed into culture tubes. After incubation, racks with culture tubes were placed on the sampler of an automatic turbidimeter. This unit, based on the discrete-sample system, measured the turbidity and printed the extinction values at a rate of 300 per hr. Calculations were computerized and the results, including statistical data, are presented in an easily readable form. The automated method is in routine use for the assays of thiamine, riboflavine, pyridoxine, cyanocobalamin, calcium pantothenate, nicotinic acid, pantothenol, and folic acid. Identical vitamin solutions assayed on different days gave variation coefficients for the various vitamin assays of less than 10%.
Failure to Detect Cell-Associated Enterotoxin B in
Staphylococcus aureus
by Immunofluorescence
Authors: Forsgren Arne , Forsum Urban , Hallander Hans O.
Published: December 2020

Enterotoxin B-producing and -nonproducing
Staphylococcus aureus
strains showed cell fluorescence when tested with fluoresceinisothiocyanate-labeled rabbit anti-enterotoxin B globulin, probably as a result of a protein A-immunoglobulin G (Ig G) interaction. No cell-bound enterotoxin B could be detected by immunofluorescence using F(ab
1
)
2
-fragments of anti-enterotoxin B globulin. However, soluble enterotoxin B could be estimated by immunofluorescence. Approximately 1,000-fold more enterotoxin B was detected by immunodiffusion as an extracellular product in the media than could be detected in the cell fraction. The results show that intact Ig G is not suitable for the detection of antigens other than protein A on the cell surface of
S. aureus
in conventional immunofluorescence. For such purposes, the use of F(ab
1
)
2
-fragments of Ig G is recommended.
Evaluation of Gentamicin for Use in Virology and Tissue Culture
Authors: Schafer Thomas W. , Pascale Andrea , Shimonaski Gerard , Came Paul E.
Published: December 2020

Data are presented comparing gentamicin to penicillin and streptomycin (Pen-Strep) in tissue culture medium with respect to a number of parameters associated with virology and tissue culture. Unlike Pen-Strep, gentamicin was stable at
p
H 2 to 10 for 15 days at 37 C in tissue culture medium, and its activity was unaffected by the presence of serum. Moreover, it was stable to autoclaving. Twenty cell types replicated normally at the suggested concentration of 50 μg/ml, and all cells were unaffected by 20 times this concentration. Evidence for its practical use in virus studies was demonstrated in that (i) it was not viricidal to ribonucleic acid or deoxyribonucleic acid viruses at 40 times the suggested concentration at 37 C, (ii) the size and number of plaques were not affected by 20 times the suggested concentration, (iii) interferon assays and production were unaffected by 20 times the suggested concentrations. Gentamicin may be uniquely useful for shipment of clinical specimens and long-term tissue culture and virus studies.
Tenuazonic Acid, a Toxin Produced by
Alternaria alternata
Authors: Meronuck R. A. , Steele J. A. , Mirocha C. J. , Christensen C. M.
Published: December 2020

Fifty-seven of 87 isolates of
Alternaria alternata
(Fr) Keissler grown on autoclaved, moist corn-rice substrate and fed to rats were lethal. The major toxin produced was isolated and characterized as tenuazonic acid. Twenty of 23 toxigenic
Alternaria
isolates examined produced tenuazonic acid. No tenuazonic acid could be detected in either of the field samples of sorghum or blackeyed peas, which were heavily invaded by
Alternaria
.
Sporostatic and Sporocidal Properties of Aqueous Formaldehyde
Authors: Trujillo Ralph , David Thomas J.
Published: December 2020

Aqueous formaldehyde is shown to exert both sporostatic and sporocidal effects on
Bacillus subtilis
spores. The sporostatic effect is a result of the reversible inhibition of spore germination occasioned by aqueous formaldehyde; the sporocidal effect is due to temperature-dependent inactivation of these spores in aqueous formaldehyde. The physicochemical state of formaldehyde in solution provides a framework with which to interpret both the sporostatic and sporocidal properties of aqueous formaldehyde.
Stability of Live Attenuated Venezuelan Equine Encephalitis Vaccine
Authors: McManus Albert T. , Robinson David M.
Published: December 2020

Reconstituted Venezulean equine encephalitis vaccine was found to retain significant titers of plaque-forming virus after storage at 4 or 22 C for 24 hr.
Identification and Aflatoxin Production of Molds Isolated from Country Cured Hams
Authors: Sutic Marija , Ayres J. C. , Koehler P. E.
Published: December 2020

Of 562 molds isolated from country cured hams, 403 isolates were of the genus
Penicillium
, 121 were
Aspergillus
, and 36 were
Cladosporium, Alternaria
, and other genera.
Bruised Poultry Tissue as a Possible Source of Staphylococcal Infection
Authors: Roskey C. T. , Hamdy M. K.
Published: December 2020

Bacteriological analyses were made on 45 swab samples secured from hands of poultry workers on processing line, on 31 bruised and 15 normal poultry tissue samples, and on 15 swabs obtained from infected lacerations and exudates of abcesses on hands, arms, chest, and abdomen of poultry workers. A total of 170
Staphylococcus
cultures were isolated from samples examined. These cultures were characterized morphologically and biochemically and then grouped into six distinct patterns.
S. aureus
was found in 86.6% of swab samples obtained from infected workers, in 40% of swabs from hands of workers who handle bruised birds, and in 38.7% of bruised tissues, and was absent from all samples obtained from hands of workers who do not handle bruised birds. All the coagulase-positive staphylococcal isolates were bacteriophage-typed, and the results showed that the same phage-type
S. aureus
was found in many poultry bruises and in infected lesions of poultry workers as well as on hands of workers who handle bruised birds. These results indicate that poultry bruises are a source of staphylococcal infection encountered among poultry workers.
Induction of Prodigiosin Biosynthesis after Shift-Down in Temperature of Nonproliferating Cells of
Serratia marcescens
Authors: Qadri S. M. Hussain , Williams Robert P.
Published: December 2020

Nonpigmented bacteria obtained by growth of
Serratia marcescens
at 38 C synthesized prodigiosin at 25 C if certain individual amino acids were added to cultures of nonproliferating cells. In order of effectiveness, the amino acids were: DL-histidine, L-proline, L-hydroxyproline, DL-alanine, L-alanine, DL-aspartic acid, D-alanine, DL-proline, L-serine, L-ornithine, L-glutamic acid, and D-proline. DL-Histidine at its optimal concentration (20 mg/ml) induced formation of prodigiosin (198 μg of prodigiosin per mg of bacterial protein) after incubation of cultures for 54 hr. Lower concentrations (10 mg/ml) of the other amino acids usually were optimum but less prodigiosin was synthesized, and the maximal amount of pigment occurred between 36 and 48 hr. DL-Methionine was not effective alone but at a low concentration (40 μg/ml) enhanced and accelerated biosynthesis of prodigiosin in the presence of other suitable amino acids. Addition of 2 mg of L-proline per ml at 0 hr induced formation of only 30 μg of prodigiosin after incubation for 42 hr, but addition at 36 hr of 5 mg more of L-proline per ml increased synthesis to 120 μg at 42 hr. Again, DL-methionine markedly augmented prodigiosin biosynthesis in these cultures. Synthesis of prodigiosin ceased if cultures were shifted from 25 to 38 C. Prodigiosin biosynthesis by the nonproliferating cells was maximum when cultures were aerated, the amount of bacterial protein was about 2.0 mg/ml, and amino acids were added at 0 hr. Bacteria synthesized prodigiosin most efficiently when they were harvested from aerated cultures grown at 38 C for 24 hr in a complete medium in a fermentor.
Rapid Ornithine Decarboxylase Test for the Identification of
Enterobacteriaceae
Authors: Fay Gunnar D. , Barry Arthur L.
Published: December 2020

Conventional methods for detecting ornithine decarboxylase activity require an extended period of incubation. However, with a few simple modifications, accurate results were obtained within a few hours rather than several days. The broth medium was modified, primarily by omitting glucose and by decreasing the
p
H to 5.5. A 1-ml amount of this broth was inoculated with one colony and then overlaid with sterile mineral oil. Within 2 to 4 hr, the
p
H increased if ornithine was decarboxylated, thus changing the color of the internal
p
H indicator to a dark purple. If the amino acid was not decarboxylated, the
p
H decreased to
p
H 5.0 to 5.2, enough to give a definite yellow color. With 347 selected clinical isolates, the rapid test gave results identical to those obtained in 1 to 4 days with Moeller's decarboxylase medium. Less reliable results were obtained with Difco's decarboxylase medium with 0.3% agar which was stabinoculated and read after 18 to 24 hr without a mineral oil seal. The rapid ornithine decarboxylase test represents a simple, accurate technique which is well suited for the clinical microbiology laboratory.