bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Staining of Extracellular Polymer for Electron Microscopy: Examination of
Azotobacter, Zoogloea, Leuconostoc
, and
Bacillus
Authors: Cagle G. D. , Pfister R. M. , Vela G. R.
Published: December 2020

Phase contrast, ultraviolet microscopy, and freeze-etching were used to determine the amount of exocellular polymer surrounding unfixed cells of four genera of bacteria:
Azotobacter vinelandii, Zoogloea ramigera, Leuconostoc mesenteroides
, and an acid-tolerant, floc-forming
Bacillus
species. Thin-sectional electron microscopy was employed to measure the effectiveness of a modified ruthenium red staining method. The results obtained with this modification of ruthenium red staining technique were compared to results obtained when previously proposed ruthenium red methods of fixation were employed. The results of these relations were then compared to the amounts of exocellular material as determined with phase-contrast microscopy, ultraviolet microscopy, and freeze-etching. The data obtained indicate that improved fixation of exocellular polymer is achieved when cells are pretreated with ruthenium red as described herein. In addition, the modified methods also reveal cytological detail not apparent when other methods of ruthenium fixation are employed.
Effect of Ultrasonic Waves on the Heat Resistance of
Bacillus cereus
and
Bacillus licheniformis
Spores
Authors: Burgos J. , Ordóñez J. A. , Sala F.
Published: December 2020

Heat resistance of
Bacillus cereus
and
Bacillus licheniformis
spores in quarter-strength Ringer solution decreases markedly after ultrasonic treatments which are unable to kill a significant proportion of the spore population. This effect does not seem to be caused by a loss of Ca
2+
or dipicolinic acid. The use of ultrasonics to eliminate vegetative cells or to break aggregates in
Bacillus
spore suspensions to be used subsequently in heat resistance experiments appears to be unadvisable.
Method for Simultaneous Detection of Proteinase and Esterase Activities in Extremely Halophilic Bacteria
Authors: Gutiérrez Carmen , González Carmen
Published: December 2020

A method was developed for simultaneous detection of proteinase and esterase activity in extremely halophilic bacteria by combining Tween hydrolysis and gelatin hydrolysis on a single plate.
Fungi Isolated from Flue-Cured Tobacco Sold in Southeast United States, 1968-1970
Authors: Welty Ronald E.
Published: December 2020

Flue-cured tobacco leaves, from low- and middle-stalk positions, offered for sale in each of two markets, within each of five tobacco types, were evaluated for moisture content (MC) and filamentous fungi during August through October in 1968, 1969, and 1970.
Alternaria alternata, Penicillium cyclopium, Aspergillus niger, Aspergillus repens
, and
Aspergillus flavus
were most frequently isolated from cultured tissue. Other filamentous fungi that grew from the tissue included species from four genera of field fungi and seven species of storage fungi. Although the MC ranged from 11.0 to 22.5%, it averaged 16.4, 16.8, and 15.9% for samples taken in 1968, 1969, and 1970, respectively. Average populations of fungi per sample over the three years ranged from 0 to 1,528,500 colonies/g of tobacco.
Radiometric Detection of Some Food-Borne Bacteria
Authors: Previte Joseph J.
Published: December 2020

Studies on detection of bacteria by radiometric techniques have been concerned primarily with aerobic species in clinical specimens. The data presented here are related to detection of aerobic and anaerobic species that are of significance in foods, by measurement of
14
CO
2
evolved from the metabolism of
14
C-glucose.
Salmonella typhimurium
and
Staphylococcus aureus
were inoculated into tryptic soy broth containing 0.0139 μCi of
14
C glucose/ml of medium. Detection times ranged from 10 to 3 hr for inocula of 10
0
to 10
4
cells/ml of broth. Heat-shocked spores of
Clostridium sporogenes
or
C. botulinum
were incubated in tryptic soy broth supplemented with Thiotone and NaHCO
3
. The medium was rendered anaerobic with N
2
. Spores were detected when 0.0833 μCi of labeled glucose was available/ml of medium but not when 0.0139 μCi of glucose was present/ml. The spores required 3 to 4 hr longer for detection than did comparable numbers of aerobic vegetative cells. The results demonstrate the importance of availability of sufficient label in the media and the potential of the application of this technique for sterility testing of foods.
Early Protection in Hamsters Immunized with Attenuated Venezuelean Equine Encephalomyelitis Vaccine
Authors: Cole Francis E. , Pedersen Carl E. , Robinson David M.
Published: December 2020

The rapid onset and persistence of homologous and heterologous protection induced by attenuated Venezuelan equine encephalomyelitis (VEE) vaccine (TC-83) were studied in the hamster, by using challenge response as the index of protection. At 8 hr postvaccination with 10
3
median immunizing doses of TC-83 vaccine, 15 to 20% of animals were protected against challenge with VEE virus as well as Eastern and Western equine encephalomyelitis viruses. The percentage of protection increased with time postvaccination until 80 to 90% homologous and heterologous protection was achieved by 18 hr postvaccination. Temporal studies indicated that early protection (days 1 to 6) correlated with vaccine viremia, and that the percentage of protection against heterologous challenge decreased with the cessation of viremia. Data are presented to indicate that the early protection phenomenon is one of interference, since little or no replication of a challenge virus occurred when it was administered during the vaccine viremia stage.
Survival of Human Dental Plaque Flora in Various Transport Media
Authors: Syed Salam A. , Loesche Walter J.
Published: December 2020

Dental plaque samples from (i) subjects with no apparent oral disease, (ii) mentally retarded subjects with periodontal disease, and (iii) subjects with active caries were collected in three transport media viz. a dithiothreitol poised balanced mineral salt solution designated as reduced transport fluid (RTF), VMG II, and modified Stuart medium (SBL). The samples were dispersed by sonic treatment, diluted in the respective medium in which they were collected, and cultured on MM10 sucrose agar. The efficiency of the transport media in the survival of dental plaque flora was determined by comparing the quantitative recovery (expressed as percentage of the initial viable count) from the specimens stored for various lengths of time. The data showed a great variation in the recovery of the oral bacterial flora from the plaque samples. VMG II and SBL served better than RTF as storage media for non-disease-associated dental plaque cultured under strict anaerobic conditions. Recoveries of bacteria from periodontal plaque specimens stored in RTF were higher than SBL and VMG II under identical conditions. The organisms present in the carious plaque samples appeared to survive much better in RTF and VMG II than in SBL as determined by conventional anaerobic culturing technique. However, VMG II showed a higher recovery of organisms from these specimens with an increase in the storage period, suggesting multiplication of the plaque flora. RTF did not allow the growth of oral bacterial flora under all experimental conditions. On the basis of the relative performance of these media it is suggested that RTF is a satisfactory medium for the transport of oral bacteria present in the samples.
Initiation of Dermatophyte Pleomorphic Strain Sporulation by Increased Aeration
Authors: Page W. J. , Stock J. J.
Published: December 2020

A normally asporogenous pleomorphic strain of
Microsporum gypseum
was induced to sporulate by controlled aeration and dehydration. Aeration of the pleomorphic strain under optimal cultivation conditions caused the initiation of a sporulation cycle with equivalent growth parameters and percentage intracellular water loss as the wild-type strain. Initiation of sporulation was not due to alteration of the medium's nutrient concentration or consistency, concentration of fungal growth by-products, or removal of volatile “staling factors.” Macroconidia formed by the pleomorphic colonies were of characteristic wildtype morphology, but germinated to form typical pleomorphic colonies, indicating that the induced sporulation was strictly phenotypic and reversible. Other asporogenous pleomorphic strains from different dermatophyte genera also were induced to form macroconidia by aeration, suggesting a similarity in sporulation induction in
Microsporum sp., Epidermophyton floccosum
, and
Trichophyton violaceum
. Initiation of sporulation by aeration further suggested that the pleomorphic mutation was one which affected the sensitivity of the pleomorphic aerial hyphae to natural sporulation inducers (i.e., decreased humidity) and did not represent a loss in the ability to form fertile macroconidia.
Chemically Defined Medium for Growth and Sporulation of
Clostridium perfringens
Authors: Ting Michael N. , Fung Daniel Y. C.
Published: December 2020

A chemically defined medium was developed that could support sporulation and growth of
Clostridium perfringens
strains ATCC 12916 and H9. This medium consisted of a modification of the basal medium of Boyd et al. plus 0.1% sodium thioglycolate and 0.5% monosodium glutamate. Five other strains grew, but did not sporulate, in this medium. With the addition of more vatamins into the medium, two more strains grew but did not sporulate. The effects of glucose, monosodium glutamate, ammonium glutamate, and sodium thioglycolate on growth and sporulation of
C. perfringens
ATCC 12916 in the defined medium was investigated.
Effect of Physiological Age and State on Survival of Desiccated
Pseudomonas aeruginosa
Authors: Skaliy Peter , Eagon R. G.
Published: December 2020

Cells of
Pseudomonas aeruginosa
harvested after 6 hr, 24 hr, 7 days, 33 days, and 120 days of incubation at 36 C varied in their resistance to the deleterious effects of desiccation. The longest survival period observed was for cells from cultures incubated for 7 days. Cells of the exponential growth phase were the most susceptible. The addition of extracellular slime from 7-day cultures to suspending medium did not increase survival of cells from the exponential growth phase. No marked differences in survival time were observed for cells of similar physiological age from cultures incubated at 20, 36, and 42 C. In comparison with the laboratory strain,
P. aeruginosa
OSU 64, used in this study, strains isolated from natural habitats and subjected to a minimum of manipulation in the laboratory were not better adapted to withstand the stress of desiccation.
An Unclassified Gram-Negative Rod Isolated From the Pharynx on Thayer-Martin Medium (Selective Agar)
Authors: Hollis Dannie G. , Wiggins Geraldine L. , Weaver Robert E.
Published: December 2020

An oxidase-positive, small gram-negative rod was isolated on Thayer-Martin medium (TM) inoculated with pharyngeal swabs obtained during surveys to detect
Neisseria
carriers. In one survey, this organism was isolated from 48% of the subjects, and 50 or more colonies were present on the majority of the primary isolation plates. Other characteristics of the organism, which has been given the provisional designation “TM-1,” include: delayed production (2 to 10 days) of acid from glucose, formation of gas during nitrate reduction, and the frequent formation of “pits” in the agar surface. On TM, nonpitting colonies of TM-1 are morphologically similar to colonies of
Neisseria gonorrhoeae
and
N. lactamica
. Comparison of the characteristics of TM-1 strains with other similar fastidious gram-negative organisms encountered in clinical laboratories indicates that TM-1 is a distinct species. Further studies are required before proper taxonomic placement can be made.
Cinemicrographic Study of the Development of Subsurface Colonies of
Staphylococcus aureus
in Soft Agar
Authors: Wilkins Judd R. , Darnell Wayne L. , Boykin Elizabeth H.
Published: December 2020

Cinemicrographic studies revealed that the development of elongated subsurface colonies of
Staphylococcus aureus
in soft agar (<0.2% agar) originated with a colony-forming unit of about 10 to 20 cells. It was then observed that small clusters of 3 to 12 cells broke off from the main colony unit and drifted away under the combined influence of gravity and Brownian motion. Once the downward or slightly sideward motion of the small clusters ceased, the clusters would continue to increase in size; at the same time, additional small clusters broke off, and the cycle was repeated until the entire colony was formed. Displacement and velocity measurements were made on the drifting small clusters. When compared with the dimensional growth rate and geometry of the subsurface colony, these showed that a correlation existed between the movement and velocity of the small clusters and the subsequent colony development. A relationship between the role of gravity reported in these results and the development of spherical colonies after rotation on a clinostat is suggested.
Evaluation of Plastic Multi-Well Plates for Serological Screening of
Salmonella
Cultures with Spicer-Edwards Pooled Antisera
Authors: Morris George K. , Steele Carolyn D. , Wells Joy G.
Published: December 2020

We compared the relative advantages of using glass test tubes and plastic multi-well plates in the serological identification of
Salmonella
cultures by the Spicer-Edwards method, and we conclude that the advantages of multi-well plates outweigh those of test tubes.
Potato Aroma of Lamb Carcasses
Authors: Tompkin R. B. , Shaparis A. B.
Published: December 2020

Rejection of lamb carcasses due to a strong potato odor was caused by
Pseudomonas taetrolens
. Although of rare occurrence, this defect can be of considerable commercial concern.
Sauerkraut Waste: a Favorable Medium for Cultivating Yeasts
Authors: Hang Y. D. , Splittstoesser D. F. , Landschoot R. L.
Published: December 2020

Sauerkraut waste was found to be more favorable for cultivating yeasts than malt extract broth and as good or better than peptone dextrose broth.
Stability of Barium Sulfate Turbidity Standards
Authors: Washington John A. , Warren Edward , Karlson Alfred G.
Published: December 2020

McFarland barium sulfate standards prepared in 1952 were compared spectrophotometrically with freshly and identically prepared standards; the results were nearly identical.
Bacterial Flocculation and Production of Poly-β-Hydroxybutyrate
Authors: Deinema Maria H.
Published: December 2020

Experiments with a number of bacteria isolated from activated sludge have shown that flocculation is independent of the presence of poly-β-hydroxybutyrate (PHB) in the cells. Several strains gave flocculent growth without any PHB detectable. Other strains, producing PHB in varying amounts, utilized this compound as an endogenous substrate, and after its disappearance the floc structure remained unchanged. The PHB content of various samples of activated sludge was found to be negligible.
Surface-Bonded Antimicrobial Activity of an Organosilicon Quaternary Ammonium Chloride
Authors: Isquith A. J. , Abbott E. A. , Walters P. A.
Published: December 2020

The hydrolysis product of 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride exhibited antimicrobial activity against a broad range of microorganisms while chemically bonded to a variety of surfaces. The chemical was not removed from surfaces by repeated washing with water, and its antimicrobial activity could not be attributed to a slow release of the chemical, but rather to the surface-bonded chemical.
Effect of
p
H and Oxygen Tension on Staphylococcal Growth and Enterotoxin Formation in Fermented Sausage
Authors: Barber Lynn E. , Deibel R. H.
Published: December 2020

Commercial fermented 0sausages that contained significant numbers of viable coagulase-positive staphylococci were found to have the growth localized in the outermost areas of the sausage where oxygen tension was highest. Staphylococci were found to be more acid-tolerant aerobically than anaerobically. With chemical acidulation of sausage, growth could be controlled both aerobically and anaerobically with approximately 1.5% glucono delta lactone. Biological acidulation with a high inoculum of
Pediococcus cerevisiae
inhibited anaerobic staphylococcal growth but failed to suppress aerobic growth completely. A staphylococcal count of approximately 4 × 10
7
cells/g of sausage appeared to be necessary to produce detectable enterotoxin A within 24 hr in sausage. A minor difference existed in the relative rates of production of the different types of enterotoxin. Detectable enterotoxin A was produced in 24 hr in sausage held in atmospheres containing 10, 15, and 20% oxygen. In an atmosphere containing 5% oxygen, toxin was detected after 48 hr of incubation. No toxin was detected after 120 hr under anaerobic conditions. Most staphylococcal strains tested initiated growth and produced detectable enterotoxin aerobically at a
p
H of 5.1 in broth media. Anaerobically, however, most strains failed to produce detectable enterotoxin below
p
H 5.7.
Agglutination of African Primate and Rodent Erythrocytes by Adenoviruses, Reoviruses, and Enteroviruses
Authors: Mutanda L. N. , Munube G. M. R.
Published: December 2020

African nonhuman primate and rodent erythrocytes were tested for agglutination by adenoviruses, reoviruses, and enteroviruses. Squirrel erythrocytes were agglutinated by reovirus serotypes and adenovirus types 3, 11, 16, and 21. Adenoviruses also agglutinated brazza monkey erythrocytes to the same titers as those obtained with either rhesus or grey monkey cells. Prototype reovirus types 1 and 2 agglutinated grey monkey erythrocytes to much lower titers than either squirrel or human group O red cells. Among the enteroviruses tested, only echovirus types 7 and 12 agglutinated grey, red-tail, brazza, and rhesus monkey erythrocytes. The specificity of agglutination of squirrel, grey, and brazza monkey erythrocytes by reoviruses, echoviruses, and adenoviruses, respectively, was confirmed by hemagglutination-inhibition tests. The titers obtained were similar to those obtained with erythrocytes usually used in these tests. Erythrocytes of bush babies, potto unstriped grass mice, swamp rat, rusty-nosed rat, bush rat, harsh-furred mice, soft-furred rat, and giant rat were not agglutinated by adenoviruses, reoviruses, or enteroviruses.
Ecology of Staphylococci in a General Medical Service
Authors: Phair John P. , Watanakunakorn Chatrchai , Goldberg Leonard , Carleton Judith
Published: December 2020

Investigation of the ecology of
Staphylococcus aureus
on the medical service of the Cincinnati General Hospital was carried out from 1964 to 1970.
S. aureus
was cultured from 1,442 patients. Overall, there was a progressive increase in the susceptibility of
S. aureus
to commonly used antibiotics, but not to penicillin. Hospital-acquired
S. aureus
remained highly resistant to all antibiotics except penicillinase-resistant penicillins. There was a progressive decline in the percentage of hospital-acquired infections from January 1964 to September 1969, followed by a rise during September 1969 to September 1970. No single bacteriophage group predominated among nosocomially acquired
S. aureus
. Major changes in the hospital environment did not appear to influence the prevalence of nasal carriage or hospital acquisition of
S. aureus
. This study identified the continuing problem of acquisition of
S. aureus
in the hospital, but no specific “epidemic strain.”
Mutagenesis and Enrichment of Auxotrophs in
Penicillium chrysogenum
Authors: Masurekar Prakash S. , Kahgan Marc P. , Demain Arnold L.
Published: December 2020

An efficient method for isolation of auxotrophs of
Penicillium chyrysogenum
involving mutagenesis with ethyl methanesulfonate followed by enrichment with sodium pentachlorophenate was developed. The auxotroph frequencies obtained were 30 to 40%.
Incidence and Identification of
Pseudomonas fluorescens
and
Pseudomonas putida
in the Clinical Laboratory
Authors: Blazevic Donna J. , Koepcke Marilyn H. , Matsen John M.
Published: December 2020

Strains of
Pseudomonas
producing fluorescin but no pyocyanin or pyorubrin were studied by biochemical and antibiotic sensitivity testing. A rapid nitrate test was found to be useful in distinguishing
P. aeruginosa
(positive) from
P. fluorescens
and
P. putida
(both negative). A shortened gelatin test differentiated
P. fluorescens
(positive) from
P. putida
(negative).
P. fluorescens
and
P. putida
were very sensitive to low levels of kanamycin and resistant to carbenicillin, a pattern just the opposite of that obtained with
P. aeruginosa
.
Technical Factors Affecting an Immunoelectrophoretic Reference System for Analysis of Mycobacterial Antigens
Authors: Janicki Bernard W. , Aron Stephen A. , Berson Alan S.
Published: December 2020

The length of immunoelectrophoretic separation patterns obtained with a reference mycobacterial antigen was reduced significantly when a continuous buffer system was used in place of the recommended discontinuous system. Varying the supporting medium by using 1% concentrations of different agar preparations in the discontinuous system also affected the separation length and resolution of the reference pattern. Measurement of the electrical resistivity of the agar medium provided an explanation of these differences on the basis of current density or field intensity applied per slide. Variation in the reference pattern obtained in differently designed electrophoresis chambers also was attributed to differences in field intensity. To avoid these obvious alterations in the separation pattern of the reference antigen, it was suggested that separation procedures described originally for the reference system be used without modification.
Edwardsiella tarda, a New Pathogen of Channel Catfish (Ictalurus punctatus)
Authors: Meyer F. P. , Bullock G. L.
Published: December 2020

Edwardsiella tarda
, an enteric, gram-negative bacterium, causes gas-filled, malodorous lesions in muscle tissue of channel catfish. Incidence and epizootiology of the disease are presented.
Hemagglutination Inhibition of Passively Sensitized Red Blood Cells
Authors: Poole George M. , Counter Fred T. , Baker Robert S.
Published: December 2020

It has been shown that sheep red blood cells sensitized with the polysaccharides of
Haemophilus influenzae
type B and pneumococcal types I, III, IV, VII, VIII, XII, and XIV respond readily in hemagglutination-inhibition testing and exhibit antigen inhibition at levels of 0.09 to 4.0 ng.
R—Factors of
Escherichia coli
from Dressed Beef and Humans
Authors: Babcock G. F. , Berryhill D. L. , Marsh D. H.
Published: December 2020

One hundred eighty
Escherichia coli
strains isolated from raw and cooked dressed beef and from healthy humans were screened for resistance to each of nine antibiotics: chlortetracycline, ampicillin, chloramphenicol, kanamycin, neomycin, nalidixic acid, dihydrostreptomycin, oxytetracycline, and tetracycline. Nearly 80% of the 98 beef isolates and 54% of the 82 human isolates were resistant to one or more of the antibiotics tested. Ampicillin resistance was most frequent among beef isolates, and dihydrostreptomycin resistance was most frequent among isolates of human origin. About 74% of the multiply resistant beef strains and 85% of the multiply resistant human strains transferred all or part of their resistance to
E. coli
K-12 recipients.
Identification of
Vibrio cholerae
by Pyrolysis Gas-Liquid Chromatography
Authors: Haddadin J. M. , Stirland R. M. , Preston N. W. , Collard Patrick
Published: December 2020

Cholera-like vibrios examined by pyrolysis gas-liquid chromatography could be distinguished from other common aerobic gram-negative bacilli, including oxidase-positive organisms, e.g.,
Aeromonas
. Vibrios in Heiberg group I were subdivided into three types on the basis of differences in one complex in the chromatogram, and these closely corresponded with the identification as classical, El Tor, or “intermediate” biotypes of
Vibrio cholerae
by conventional methods.
Microbiological Testing of Skylab Foods
Authors: Heidelbaugh N. D. , Rowley D. B. , Powers E. M. , Bourland C. T. , McQueen J. L.
Published: December 2020

The Skylab manned space flight program presented unique food microbiology problems. This challenge was successfully met by careful evaluation of the total Skylab food system by considering the nature of Skylab foods, their processing and handling, and Skylab food safety requirements. Some of the unique problems encountered with the Skylab foods involved: extended storage times, variations in storage temperatures, no opportunity to resupply or charge foods after launch of the Skylab Workshop, first use of frozen foods in space, first use of a food-warming device in weightlessness, relatively small size of production lots requiring statistically valid sampling plans, and use of the food as an accurately controlled segment of sophisticated life science experiments. Consideration of all of these situations generated the need for definitive microbiological tests and test limits. These tests are described in this paper along with the rationale for their selection. Test results are reported which show successful compliance with the test limits.
Comparison of Three Blood Culture Media for Recovery of Anaerobic Bacteria
Authors: Washington John A. , Martin William Jeffery
Published: December 2020

Comparison of an anaerobic brain heart infusion broth with tryptic soy broth and Thioglycollate medium failed to demonstrate significant differences in isolation rates of anaerobic bacteria from blood.
Oxidative Activation of
Bacillus cereus
Spores
Authors: Cochran Stuart A. , Ordal Z. John
Published: December 2020

A study was made of the activation of
Bacillus cereus
strain T spores by using the oxidizing agent sodium perborate. The degree of activation was measured with constant germination conditions by using L-alanine, inosine, adenosine, and L-alanine plus adenosine as germination stimulants. The germinal response following the various treatments was compared with the responses obtained with heat activation. It was concluded that the optimal time for activation with 30 mM sodium perborate at room temperature was about 4 hr. If the exposure time was greatly extended, the spores would germinate spontaneously. When the perborate treatment followed heat activation, the germinal response to L-alanine was stimulated, to inosine retarded and without apparent effect for adenosine or L-alanine plus adenosine. Results of experiments designed to demonstrate deactivation by slow oxidation showed that spores activated with sodium perborate were not deactivated by slow oxidation, whereas those activated by heat were. A deactivation study using mercaptoethanol as the deactivation agent showed that both methods of activation could be deactivated after a 24-hr exposure, but this deactivation was reversible by extending the exposure to mercaptoethanol. The results of heat-sensitivity studies revealed that about 70% of the sodium perborate-activated spores were heat sensitive after 60 min in a germination menstruum of L-alanine plus adenosine, whereas similarly treated heat-activated and nonactivated spores were about 99.99% heat sensitive, respectively.
Extraction of Equine Infectious Anemia Immunodiffusion Antigen with the Aid of the Chaotropic Agent, Thiocyanate
Authors: Hart L. T. , Broussard E. A.
Published: December 2020

Immunodiffusion antigen from spleens of horses infected with equine infectious anemia virus was prepared by methods employing freeze-thaw cycles and thiocyanate treatment. Thiocyanate (0.5 M) permitted the recovery of the greatest amount of antigen. Furthermore, it was most effective for recovery of immunodiffusion antigen from spleens which yielded unsatisfactory concentrations of antigen by the conventional freeze-thaw or water-extraction methods. The reactivity of the antigen did not appear to be affected by this chemical treatment.
Evaluation of the Salmonellae Fluoro-Kit for Fluorescent-Antibody Staining
Authors: Insalata N. F. , Dunlap W. G. , Mahnke C. W.
Published: December 2020

An evaluation of the newly developed Clinical Sciences, Inc. Salmonellae Fluoro-Kit, which attempts to standardize the various aspects of the fluorescent-antibody (FA) procedure, was performed with 120 naturally contaminated human food, animal feed, and raw material samples. The Association of Official Analytical Chemists (AOAC) method for the detection of salmonellae was used as the control method. The Fluoro-Kit was found to be simple and conveniento to use. The results of this preliminary study show an industrially acceptable rate of recovery of salmonellae by using the Fluoro-Kit in comparison with the A.O.A.C. method. The Fluoro-Kit shows promise as a rapid, salmonellae FA screening method. Problems originally encountered in the application of the Fluoro-Kit are discussed. According to the manufacturer, strict adherence to the now revised procedures included in the Fluoro-Kit will control these problems.
Application of the Most-Probable-Number Procedure to Suspensions of
Leptospira autumnalis
Akiyami A
Authors: Schiemann D. A.
Published: December 2020

Various statistical tests are presented as evidence that the most-probable-number (MPN) procedure is a reliable method for estimating the density of washed-cell suspensions of
Leptospira autumnalis
Akiyami A.
Nonspecific Adsorption of Proteins to Microplates
Authors: Inouye Sakae
Published: December 2020

When a solution of purified adenovirus hexon proteins was diluted in polystyrene microplates without carrier proteins in the diluent, a higher rate of hexon adsorption to the microplates at higher dilutions took place. Addition of gelatin (0.01%), bovine serum albumin (0.01%), or calf serum (0.2%, vol/vol) to the diluent effectively prevented this adsorption. The adsorption to the microplates of adenovirions and measles virions was also prevented by the carrier proteins in the diluent. Certain additional features which distinguish the microtechnique of Takatsy from conventional macromethods are also discussed.
Auxotab—a Device for Identifying Enteric Bacteria
Authors: Rhoden D. L. , Tomfohrde K. M. , Smith P. B. , Balows A.
Published: December 2020

A multitest system called the Auxotab that uses ten dehydrated reagents on a paper card has been evaluated with 417 known stock cultures of
Enterobacteriaceae
. In double-blind studies with the Auxotab, 87% of the strains tested were correctly identified. Results of this study indicate that there is a need for modification of the product in regard to ease of handling, time required for use, and accuracy of identification of enteric bacteria.
Lysogeny in Lactic Streptococci Producing and Not Producing Nisin
Authors: Kozak Witold , Rajchert-Trzpil Marianna , Zajdel Jolanta , Dobrzański Władysław T.
Published: December 2020

Eighty-seven strains of lactic streptococci (46 of
Streptococcus lactis
, 24 of
S. diacetilactis
, and 17 of
S. cremoris
) were tested for lysogeny; 12
S. lactis
strains produced nisin. Lysogeny was found in five
S. lactis
strains (two of them were nisin producers) and in two
S. diacetilactis
strains. Four
S. lactis
and two
S. diacetilactis
lysogens liberated phages both spontaneously and after ultraviolet treatment, and one
S. lactis
strain liberated phages spontaneously only. No lysogens were found among the
S. cremoris
strains tested. An initial characterization of the lysogens and their phages was made. The lytic spectrum of some of the examined phages was very narrow (homospecific), whereas that of others was wide, including strains of the three investigated species.
Human Leukocyte Interferon Produced by Use of an Antibody-Free Human Serum Fraction
Authors: Goore Moshe Y. , Dickson Judith H. , Lipkin Saul
Published: December 2020

An antibody-free human serum fraction has been prepared by ammonium sulfate precipitation. This fraction can be substituted for whole serum in the production of optimal yields of interferon by induced human leukocytes.
Determination of Endotoxicity in Bacterial Vaccines
Authors: Wong K. H. , Miller C. E. , Feeley John C. , Chan Y. K.
Published: December 2020

Endotoxicity of bacterial vaccines was quantitated in mice by using actinomycin D as potentiating agent. The results were compared with those obtained by the mouse weight gain test. The lethality of
Escherichia coli
lipopolysaccharide was increased 2,140 times when 12.5 μg of actinomycin D was used. The mean lethal dose values of heated and unheated pertussis vaccines were similar in the actinomycin D enhancement assay, but the unheated vaccine was significantly more toxic in the mouse weight gain test. Acetone-inactivated typhoid vaccine was slightly less toxic than the heat-phenol-inactivated vaccine in both the actinomycin D enhancement assay and mouse weight gain test. Endotoxicity of experimental vaccines prepared by extraction of
Pseudomonas aeruginosa
strains was high as compared with
E. coli
lipopolysaccharide. The BALB/c mice were about four times more susceptible than the random bred NIH strain mice. The results indicate that the actinomycin D enhancement assay had the advantages of being more sensitive and probably more specific.
Effect of Selected Lactic Acid Bacteria on Growth of
Staphylococcus aureus
and Production of Enterotoxin
Authors: Haines William C. , Harmon L. G.
Published: December 2020

Representative strains of 15 species of lactic acid bacteria were examined for their ability to influence growth of
Staphylococcus aureus
and production of enterotoxin in associative culture. Among the organisms used as effectors the streptococci were most inhibitory, followed by
Pediococcus cerevisiae
. The lactobacilli and
Leuconostoc citrovorum
were not inhibitory to growth and only slightly inhibitory to production of enterotoxin. Enterotoxin was detected in all cultures in which the population of
S. aureus
reached 8 × 10
7
per ml. At lower
S. aureus
populations no enterotoxin was detected after incubation for 48 h. Mechanisms of inhibition of growth and enterotoxin production by
S. aureus
strain 243 grown in association with
Streptococcus lactis
A64 or
P. cerevisiae
10791 in APT broth were investigated. Competition for vital nutrients, especially niacin and biotin, and probably production of hydrogen peroxide contribute to inhibition. Production of lactic acid appears to inhibit growth of
S. aureus
in the early but not the late stages of incubation.
Utilization of
n
-Alkanes by
Cladosporium resinae
Authors: Teh J. S. , Lee K. H.
Published: December 2020

Four different isolates of
Cladosporium resinae
from Australian soils were tested for their ability to utilize liquid
n
-alkanes ranging from
n
-hexane to
n
-octadecane under standard conditions. The isolates were unable to make use of
n
-hexane,
n
-heptane, and
n
-octane for growth. In fact, these hydrocarbons, particularly
n
-hexane, exerted an inhibitory effect on spore germination and mycelial growth. All higher
n
-alkanes from
n
-nonane to
n
-octadecane were assimilated by the fungus, although only limited growth occurred on
n
-nonane and
n
-decane. The long chain
n
-alkanes (C
14
to C
18
) supported good growth of all isolates, but there was no obvious correlation between cell yields and chain lengths of these
n
-alkanes. Variation in growth responses to individual
n
-alkane among the different isolates was also observed. The cause of this variation is unknown.
Comparison of the Direct Agglutination and Indirect Hemagglutination Tests in the Determination of Blood Serum Titers to
Escherichia coli
Organisms
Authors: Schipper I. A. , Kelling C. , Ebeltoft H. , Graves D.
Published: December 2020

A comparison of the direct agglutination test and the indirect hemagglutination test for the detection of blood serum antibodies to
Escherichia coli
organisms indicated that these serological tests were comparable. In some instances the indirect hemagglutination test provided higher endpoint readings. Preparation of the antigens for the indirect hemagglutination test was more time consuming than for the direct agglutination test. Crude extract and purified polysaccharides were comparable as red blood cell sensitizing agents.
Long-Term Survival of
Leptospira
in a Biphasic Culture Medium Containing Charcoal
Authors: Myers Donald M. , Varela-Díaz Victor M. , Siniuk Alicia A.
Published: December 2020

A comparison was made of the survival of 28 leptospiral serotypes in Fletcher semisolid medium and in the same medium containing a basal layer of Fletcher medium plus 0.7% of agar and 0.5% of activated animal charcoal. A year after culture, more motile leptospires were observed by microscope examination in the biphasic medium. Two years after culture, 4 serotypes grown in the biphasic medium and 11 in Fletcher medium did not show motile cells. Nineteen of the serotypes maintained in Fletcher medium and 25 in the biphasic medium for 2 years grew on subculture into Fletcher medium. Subcultures from the biphasic medium showed the characteristic leptospiral ring growth earlier during the incubation period.
Evaluation of a Red Cell Agglutination Test for Detection of Australia Antigen (HB Ag)
Authors: Germain Kathryn H. , Sturdivant Sherry K. , Rightsel Wilton A.
Published: December 2020

An investigational red cell agglutination (RCA) test was evaluated for sensitivity in detecting and titering hepatitis B antigen (HB Ag) in comparison with two counterelectrophoresis (CEP) systems and a solid-phase radioimmunoassay (RIA). The RCA procedure was found to be significantly more sensitive than the CEP methods and compares favorably in sensitivity with the solid-phase RIA, detecting even lower concentrations of the HB Ag. Since the RCA test can be completed in 2 to 3 h and requires relatively inexpensive equipment, it offers a highly sensitive and rapid procedure suitable for use in blood banks to screen donors or detect low levels of antigen in serum of patients.
Distribution of Steroid 1-Dehydrogenation and Side-Chain Degradation Enzymes in the Spores of
Fusarium solani
: Causes of Metabolic Lag and Carbohydrate Independence
Authors: Plourde Rosaire , Hafez-Zedan Hamdallah
Published: December 2020

The spores of a strain of
Fusarium solani
1-dehydrogenate ring A and cleave the 17β-acetyl side chain of 17α-hydroxypregn-4-ene-3,20-dione (17α-hydroxyprogesterone) to give 17α-hydroxypregna-1,4-diene-3,20-dione (the 1-dehydro analogue) and little androsta-1,4-diene-3,4-diene-3,17-dione (androstadienedione). A 4-h lag period is observed in the course of metabolism, and there are no requirements for external additives. Exoenzymes or surface enzymes bound to the cell outside the plasma membrane, either in the periplasmic space or bound to the cell wall, cannot be detected. The spore activity is not destroyed by treatment with aqueous HCl (pH 1.50), indicating that the 1-dehydrogenation and side-chain degradation enzymes are located away from the surface of the spores. Phenethyl alcohol destroys the spore permeability barriers, and it is also likely that it exposes its enzymes to acid inactivation. The action of phenethyl alcohol is reversible at low concentrations and irreversible at high concentrations. This investigation shows that: (i) the spore 1-dehydrogenating and side-chain-degrading enzymes appear to be bound to, or imbedded in, the plasma membrane; (ii) the lag period observed in the course of metabolism of the steroid by the spores might be required for enzyme activation or diffusion of the substrate through the cell wall; and (iii) the internal metabolities of the spores, that might be required for the conversion process, appear to be present in a nondiffusible form or bound to intrasporal macromolecules.
Induction of Prophage in
Streptococcus lactis
C2 by Ultraviolet Irradiation
Authors: McKay L. L. , Baldwin K. A.
Published: December 2020

Streptococcus lactis
C2 has been used extensively by many laboratories in studies on the metabolism of lactic streptococci. By using ultraviolet irradiation as the inducing agent, this organism was shown to release a small bacteriophage, indicating that it is a lysogenic strain. The induced phage had a head approximately 40 nm in diameter and a tail length and width of about 180 and 6 nm, respectively. A structure resembling a collar was observed. Attempts to isolate a sensitive indicator strain for the virus were unsuccessful.
Rapid, Sensitive Assay for Staphylococcal Enterotoxin A by Reversed Immuno-osmophoresis
Authors: Kimble C. E. , Anderson A. W.
Published: December 2020

Reversed immuno-osmophoresis using phenylsulfonated immune gamma
2
-globulin is a rapid sensitive method of assaying for staphylococcal enterotoxin A. The technique is compared with other serological methods.
Response of Hypersensitive Mice to the Footpad Injection of Living Homologous or Heterologous Mycobacteria: Preliminary Report
Authors: Kubica George P. , Dunbar Frank P. , Kim Thomas H.
Published: December 2020

Mice sensitized by the injection of viable mycobacteria into one of the hind footpads responded to a second injection of mycobacteria (3 to 4 weeks later), introduced into the contralateral foot, with a degree of footpad swelling that was both accelerated and exaggerated beyond that observed after the first inoculation. The degree of specificity of this reaction (i.e., response to homologous versus heterologous mycobacteria) was comparable to that previously reported for dermal reactions of hypersensitive guinea pigs to tuberculin or tuberculin-like antigens from mycobacteria. In preliminary studies it was impossible to achieve this state of specific sensitization by vaccinating mice subcutaneously with water-in-oil emulsions of heat-killed mycobacteria; reasons for the failure are discussed. It is suggested that this tool could prove useful in both taxonomic and immunological investigations. Advantages and disadvantages of the mouse footpad test in relation to the dermal skin test in guinea pigs are discussed.
Selective Isolation of Leptospiras from Contaminated Material by Incorporation of Neomycin to Culture Media
Authors: Myers Donald M. , Varela-Díaz Víctor M.
Published: December 2020

Incorporation of neomycin to the culture medium was found to be effective in inhibiting
Escherichia coli
contaminants without interfering with the growth of serotype
L. autumnalis
. The growth of 12 other
Leptospira
serotypes was unaffected by the addition of 300 μg of neomycin per ml to Ellinghausen medium or 5 μg/ml to Fletcher medium. Neomycin-containing medium was found to be of value in the isolation of leptospiras from cultures of blood from infected laboratory animals. A higher percentage of isolates was obtained in swine kidneys from an abattoir in medium containing neomycin than resulted from the same medium without antibiotic or with 5-fluorouracil. Contaminated leptospiral cultures growing in media with 5-fluorouracil were purified by subculturing into neomycin-containing media.
Effect of Zinc, Copper, and Iron on Ochratoxin A Production
Authors: Steele J. A. , Davis N. D. , Diener U. L.
Published: December 2020

The effect of zinc, copper, and iron levels on production of ochratoxin A by Aspergillus ochraceus
Wilhelm in a synthetic medium in a shake culture was investigated. Optimal concentrations of ZnSO
4
, CuSO
4
, and FeCl
3
for ochratoxin A production were 0.055 to 2.2 mg/liter, 0.004 to 0.04 mg/liter, and 1.2 to 24 mg/liter, respectively. Zinc and copper levels greater than optimum reduced the rate of ochratoxin accumulation without altering either glutamate or sucrose utilization. Ochratoxin A production was correlated with rapid utilization of sucrose by the fungus and decreasing pH of the medium. Most of the glutamic acid was removed from the medium prior to ochratoxin production. There was no correlation between mycelial dry weight and ochratoxin A production.
Diagnosis of Meningococcal Arthritis by Immunoelectrophoresis of Synovial Fluid
Authors: Feldman Sheldon A. , DuClos Terry
Published: December 2020

In a case of meningococcal arthritis, the organism was identified promptly through examination of synovial fluid by countercurrent immunoelectrophoresis.
Control of Surface Wound Infection: Skin Versus Synthetic Grafts
Authors: Saymen Dennis G. , Nathan Paul , Holder Ian Alan , Hill Edward O. , Macmillan Bruce G.
Published: December 2020

Auto-, iso-, or xenografts of skin and synthetics placed on surface wounds freshly contaminated with
Pseudomonas aeruginosa
stabilizes the wound bacterial population in rats over a 24-h period. When these wounds contained a bacterial contamination established for 24 h prior to grafting, only skin and the synthetic polyhydroxyethylmethacrylate were effective in lowering the initial bacterial concentration. Polyurethane foam and nylon velour were not effective in the established infection model. Skin placed on a contaminated wound for 2 h or longer appeared to equilibrate with the underlying muscle so that the bacterial count per milligram of skin was similar to that of the muscle. It was suggested that this preparation would be useful to obtain an estimate of surface contamination without biopsy of the infected muscle. Skin grafts in place for 2 h significantly lowered the bacterial count in a wound with an established infection. A second decrease occurred between 4 and 24 h after grafting. Histological studies of contaminated and exposed panniculus muscle showed that leukocytes tend to migrate from the muscle surface to its base. Skin grafts and polyhydroxyethylmethacrylate appear to reverse the white cell migration so that the cells move toward the surface of the muscle with preservation of normal staining characteristics in the muscle. It is suggested that this alteration in cell movement after graft application might modify the white cell function and result in a greater bactericidal activity. Apparently, grafts lower bacterial levels in an established infection by modifying the host response to the surface contamination.
Semi-Commercial-Scale Production of Japanese B Encephalitis Virus Vaccines from Tissue Culture
Authors: Singh Balwant , Chang Ik Chin , Hammon W. McD.
Published: December 2020

This study was undertaken to modify and develop procedures for tissue culture-inactivated Japanese B encephalitis (JBE) virus vaccine production in large quantities. Various types of glass bottles were tried and, considering many advantages, long cylindrical roller (CR) bottles were selected. Several variables were investigated including number and volume of trypsinized cells to be seeded, volume of growth medium required for optimum cell growth, amount of calf serum, and volume of harvest medium for a high-titer virus yield. A good confluent cell sheet in CR bottles was obtained within a week by increasing the calf serum from 4 to 10% and when such tissue in a CR bottle was inoculated with 45,000 viral mean tissue culture infective doses directly into the medium, the cytopathological effects (CPE) appeared on day 5. High-titer virus yields were obtained when the harvests were made at 4
+
CPE using medium 199 with 2% human albumin at pH 8.3 to 8.5. No appreciable gain in titer was found from such harvests by blending to release intracellular virions. The production methods finally adopted gave consistently good results, and several inactivated JBE virus vaccine lots with minimum immunizing doses, ranging from 0.005 to 0.017 ml, were prepared using a large number of CR bottles in a simulated commercial-scale production system.