bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Culture Medium and Carbon Dioxide Concentration on Growth of Anaerobic Bacteria Commonly Encountered in Clinical Specimens
Authors: Stalons Don R. , Thornsberry Clyde , Dowell V. R.
Published: December 2020

Representative strains of anaerobic bacteria from human infections were used to evaluate broth media, gas mixtures, and inocula for use in developing a procedure for performing minimal inhibitory concentration antimicrobic susceptibility tests. Nine commercially available media, including two that were chemically defined, were tested. Tests were performed in atmospheres with carbon dioxide concentrations between 2.5 and 10% and also in the GasPak system (BBL) that had a disposable hydrogen-carbon dioxide generator. Growth curves on each organism grown in schaedler broth and a 5% carbon dioxide atmosphere were used to determine growth characteristics, equate time of the particular growth phases to turbidity readings, and determine the numbers of viable organisms present in the culture. Schaedler broth proved to be most advantageous in combination with an atmosphere of 5% carbon dioxide, 10% hydrogen, and 85% nitrogen. The growth curve studies yielded valuable data on the rapidity and quantity of growth under these conditions. We believe these data have provided information which can be used as the basis for developing a standardized procedure for antimicrobic susceptibility testing for anaerobic bacteria.
Thermophilic Mixed Culture of Bacteria Utilizing Methanol for Growth
Authors: Snedecor Bradley , Cooney Charles L.
Published: December 2020

A thermophilic mixed population of bacteria, capable of utilizing methanol as its sole carbon-energy source at temperatures up to 65 C, was selected by enrichment and studied. A maximal cellular yield of 0.42 g per g of methanol was observed at 50 to 56 C. The maximal specific growth rate of the mixed population in continuous culture at 56 C was greater than 0.32 per h. The amino acid profile of the mixed culture indicated that a high quality protein was produced and the protein content was 71%. The properties of this culture and its ability to grow at elevated temperatures are discussed in terms of single-cell protein production and the treatment of industrial waste.
Aflatoxin-Producing Strains of
Aspergillus flavus
Detected by Fluorescence of Agar Medium Under Ultraviolet Light
Authors: Hara S. , Fennell D. I. , Hesseltine C. W.
Published: December 2020

The fluorescence method of detecting aflatoxin-producing strains of
Aspergillus flavus
and related species utilizes the ultraviolet-induced fluorescence of aflatoxin produced in a modified Czapek's solution agar containing corn steep liquor, HgCl
2
, and (NH
4
)H
2
PO
4
instead of NaNO
3
. The presence of aflatoxin is confirmed by thin-layer chromatography of CHCl
3
extracts of the fluorescing agar.
Plaque Assay for Avirulent (Lentogenic) Strains of Newcastle Disease Virus
Authors: Lomniczi B.
Published: December 2020

Avirulent (lentogenic) strains of Newcastle disease virus form plaques on chicken embryo lung monolayers in 48 to 72 h.
Epidemiological Tracing of
Pseudomonas aeruginosa
: Antibiogram and Serotyping
Authors: Dayton Sandra L. , Blasi Dianna , Chipps Donna D. , Smith R. F.
Published: December 2020

The spread of a particular strain of
Pseudomonas aeruginosa
through a pediatric burn unit was monitored using serological typing and antibiotic susceptibility data.
Biophysical-Immunological Assay for Ribonucleic Acid Type C Viruses
Authors: Olpin J. , Oroszlan S. , Gilden R. V.
Published: December 2020

A biophysical and immunological method for characterization of ribonucleic acid type C virus suspensions is described. The method provides a relationship to the total viral mass concentration of the particle titer, the gs antigen titer, and the ultraviolet absorbance (268 nm) of 2% sodium dodecyl sulfate digests. Data for murine, rat, feline, and hamster viruses are shown to be analogous within the test limitations. From these data, an assessment of the viral purity can be made, the structural integrity can be evaluated, an approximate molecular weight can be computed, and the mole ratio of gs antigen can be determined.
Production of Coenzyme A by
Sarcina lutea
Authors: Nishimura Noriyuki , Shibatani Takeji , Kakimoto Toshio , Chibata Ichiro
Published: December 2020

To develop an efficient method for the production of coenzyme A (CoA), optimal conditions for its formation from pantothenic acid, cysteine, and adenine were studied. A number of microorganisms were screened for production of CoA. Strains belonging to the genera
Sarcina, Bacillus, Microbacterium, Micrococcus
, and
Serratia
accumulated CoA. Among these,
Sarcina lutea
was selected as the best organism, and the culture conditions for the production of CoA were investigated with this organism. Under optimal conditions, 600 μg of CoA per ml was accumulated in the culture broth. CoA was readily isolated in high purity by the use of charcoal, diethylaminoethyl-cellulose, Sephadex G-25, and Dowex-50. Yields of isolated CoA were over 33% from culture broth.
Physiology of Sporeforming Bacteria Associated with Insects: Radiorespirometric Survey of Carbohydrate Metabolism In the 12 Serotypes of
Bacillus thuringiensis
Authors: Nickerson Kenneth W. , Julian Grant St. , Bulla Lee A.
Published: December 2020

Radiorespirometry was used to compare the primary pathways of glucose catabolism in 18 strains of
Bacillus thuringiensis
representing the 12 established serotypes. Every strain utilizes the Embden-Meyerhof-Parnas pathway almost exclusively; pentose-phosphate pathway participation is minor. The Embden-Meyerhof-Parnas pathway predominates regardless of whether the cells were grown in a minimal medium or one containing yeast extract. The results indicate that the absolute requirement for citrate and related compounds is not a result of defective citrate or glucose transport and metabolism.
Fate of Ochratoxin A and Citrinin During Malting and Brewing Experiments
Authors: Krogh P. , Hald B. , Gjertsen P. , Myken F.
Published: December 2020

The fate of ochratoxin A and citrinin during malting and brewing processes was studied by the use of naturally contaminated lots of barley, as well as by the addition of crystalline toxins to the mash. Complete degradation was observed for ochratoxin A from moderately contaminated barley lots and for citrinin added to mash. The use of highly contaminated barley resulted in transmission of ochratoxin A into the beer, but only 2 to 7% of the initial content was detected, corresponding to levels of 6 to 20 μg of ochratoxin A per liter of beer. Barley lots with this high ochratoxin contamination (1,000 to 5,000 μg/kg) will be easily detected and, therefore, because of pronounced deterioration, should be rejected during inspection upon admittance to the breweries.
Occurrence of Potential Pathogens in Water Containing Ornamental Fishes
Authors: Trust T. J. , Bartlett K. H.
Published: December 2020

The bacterial population of the water supplied with ornamental fish purchased from retail outlets was examined qualitatively and quantitatively. As many as 10
9
viable aerobic organisms per 100 ml were present, with fecal coliform counts as high as 10
5
per 100 ml.
Citrobacter, Escherichia, Pseudomonas
, and
Vibrio
were isolated from 75% or more of the samples, whereas
Aeromonas, Alcaligenes, Enterobacter, Flavobacterium
, and
Streptococcus
were isolated from 45 to 65% of the samples.
Pseudomonas aeruginosa, Edwardsiella tarda
, and
Klebsiella pneumoniae
were also isolated.
Development of a Defined Minimal Medium for the Growth of
Neisseria gonorrhoeae
Authors: La Scolea Leonard J. , Young Frank E.
Published: December 2020

This investigation describes the development of a solid and a liquid medium (Gonococcal Genetic Medium; GGM) which support the rapid growth of 41 gonococcal clinical isolates and laboratory strains with a minimum number of nutritional components. The complete medium contains minimal salts, eight amino acids, two nitrogen bases, vitamins, coenzymes, key metabolic intermediates, and some miscellaneous components. Results indicate that GGM can be modified and simplified even further than we described. In liquid GGM, several gonococcal strains grew logarithmically after a 2- to 3-h lag period with generation times ranging from 72 to 115 min, reaching optical densities of 175 to 320 Klett units in the presence of seven amino acids and in the absence of a CO
2
atmosphere. The development of a solid and a liquid defined minimal medium such as GGM should greatly broaden the avenues of experimentation for biochemical genetic studies with
N. gonorrhoeae
, especially gonococcal genetic transformation.
N. gonorrhoeae
can be classified into eight major and minor phenotypic groups, depending on its growth responses on GGM to just five amino acids: cysteine and cystine, arginine, proline, isoleucine, and serine. Such results demonstrate the feasibility of using GGM as a simple, sensitive, rapid probe for investigating the epidemiological patterns of gonorrhea.
Survival of
Azotobacter
in Dry Soil
Authors: Vela G. R.
Published: December 2020

Detection of viable
Azotobacter
in soils stored in the laboratory for more than 10 years suggests that these bacteria can remain dormant in nature for prolonged periods of time. Studies of dried cultures show that cysts of
A. vinelandii
12837 remain viable for at least 10 years, whereas vegetative cells do not survive for even 1 year under the same conditions.
Radiometric Method for the Detection of Coliform Organisms in Water
Authors: Bachrach Uriel , Bachrach Zelilah
Published: December 2020

A new radiometric method for the detection of coliform bacteria in water has been described. The method is based on the release of
14
CO
2
from [
14
C]lactose by bacteria suspended in growth medium and incubated at 37 C. The evolved
14
CO
2
is trapped by hyamine hydroxide and counted in a liquid scintillation spectrometer. The method permits the detection of 1 to 10 organisms within 6 h of incubation. Coliform bacteria suspended in water for several days recover from starvation and may be quantitated by the proposed method. Bacteria from water samples may also be concentrated by filtration through membrane filters and detected by the radiometric assay.
Trichophytin Extraction: Biological Comparison of Trichophytin Extracted from
Trichophyton mentagrophytes
Grown in a Complex Medium and a Defined Medium
Authors: Ottaviano Paul J. , Jones Henry E. , Jaeger June , King Robert D. , Bibel David
Published: December 2020

The extraction of antigens (trichophytin) from
Trichophyton mentagrophytes
var.
asteroides
grown in both a complex medium and a defined medium proved to be reproducible and feasible. These extracts were first evaluated by skin testing in both infected and noninfected guinea pigs. Further evaluation and standardization was accomplished in selected humans by comparing these antigens to a trichophytin known to elicit allergic reactions to the dermatophytes. The trichophytins produced by this extraction procedure gave no false positive (or negative) skin test reactions. These antigens did, however, reliably elicit allergic sensitivity of both the immediate and delayed type. The potency of both complex and defined media antigen was shown to be equal to that of the standard trichophytin.
Evaluation of a Plaque Assay for the Maedi-Progressive Pneumonia-Visna Viruses
Authors: Trowbridge R. S.
Published: December 2020

A simple and direct plaque assay for maedi virus, two strains of progressive pneumonia virus, and two strains of visna virus has been developed and evaluated. The technique allows the plaques formed by these viruses to be localized without disturbing the host-cell substrate of sheep choroid plexus cells or the gelled maintenance medium over the host-cell monolayer. Diethylaminoethyl-dextran supplementation of the medium used to overlay strain K796 visna virus-infected cultures decreases the time required for maximum plaque development from 12 to 10 days, enhances the contrast of the plaques, increases the titer of plaque-forming units, and permits a plaque size heterogeneity to be realized. Both large and small plaques occur in cultures infected with the visna viruses, one strain of progressive pneumonia virus, or maedi virus. In contrast, the plaques observed in cultures infected with the second strain of progressive pneumonia virus are relatively homogeneous in size.
Typing
Herpesvirus hominis
Antibodies and Isolates by Inhibition of the Indirect Hemagglutination Reaction
Authors: Back Arthur F. , Schmidt Nathalie J.
Published: December 2020

Inhibition of the indirect hemagglutination reaction (IHA inhibition) was compared to several other methods for type-specific identification of
Herpesvirus hominis
(HVH) antibodies and isolates. The method appears to have the greatest value for typing antibodies for HVH type 1 and HVH type 2 in human sera; identification of antibody type was relatively simple and results were definitive. The IHA-inhibition test permitted serological diagnosis of HVH type 2 infection in three young adults with meningoencephalitis, thus extending the mounting evidence that nervous system involvement with this virus type is not limited to neonatal infections. II/I indexes of neutralizing or IHA antibody gave an accurate indication of the presence of HVH type 2 antibody in those sera containing type 2 antibody by IHA inhibition, but they indicated the presence of HVH type 2 antibody in one-half or more of the sera shown to contain only HVH type 1 antibody by IHA inhibition. For typing HVH isolates, the IHA-inhibition test gave results identical to those obtained by direct fluorescent-antibody staining using cross-absorbed conjugates, but the IHA-inhibition test was much more cumbersome and time-consuming to perform than was direct fluorescent-antibody staining. A microneutralization technique for virus typing also gave results identical to those obtained with direct fluorescent-antibody staining and IHA inhibition. However, typing HVH isolates by plaque size or the differential effect of incubation temperature was found to be less definitive and accurate.
Thermoradiation Inactivation of Naturally Occurring Bacterial Spores in Soil
Authors: Reynolds Marcel C. , Lindell Kermit F. , David Thomas J. , Favero Martin S. , Bond Walter W.
Published: December 2020

Samples of soil collected from the Kennedy Space Center near the spacecraft assembly facilities were found to contain microorganisms very resistant to conventional sterilzation techniques. The inactivation kinetics of the naturally occurring spores in soil were investigated by using dry heat and ionizing radiation, first separately and then simultaneously. Dry-heat inactivation kinetics of spores was determined at 105 and 125 C; radiation inactivation kinetics was determined for dose rates of 660 and 76 krads/h at 25 C. Simultaneous combinations of heat and radiation were then investigated at 105, 110, 115, 120, and 125 C, with a dose rate of 76 krads/h. Combined treatment was found to be highly synergistic, requiring greatly reduced radiation doses to accomplish sterilization of the population.
8-Classtype Tallying Device and Counter
Authors: Adams James N.
Published: December 2020

An electronic device using transistor-transistor-logic integrated circuits as primary building blocks was designed and constructed to accumulate counts for eight classtypes. Selection of the classtypes is provided for by three encoders, X, Y, and Z. Using these encoders allows selection of memory counters for accumulations of 0 to 99 counts per classtype. Making X, Y, and Z the input equivalents of three genes permitted direct tallying and accumulation of totals of individual phenotypes for recombinant progeny containing three scorable genes. The use of the device as a simple one-of-four colony counter is described. Use of the instrument for obtaining counts of multiply characterized colonies was possible. In all tested instances, tedium and the labor of obtaining differential counts was reduced by more than fourfold with a great increase in accuracy of count accumulations. Complete information is provided for the fabrication of the instrument for use in individual laboratories.
Evaluation of the Gonosticon Dri Dot Test in Females with a Low Incidence of Gonorrhea
Authors: Dyckman John D. , Wende Reuben D. , Williams Robert P.
Published: December 2020

A group of 765 females attending a Planned Parenthood Clinic was screened for gonorrhea by inoculating Thayer-Martin plates and Transgrow bottles with specimens from the cervix. Blood was obtained at the same time and tested for anti-gonococcal antibody by using the Gonosticon Dri Dot test. In this low-incidence group, 18 positive cultures were detected by culture on Thayer-Martin plates, whereas Transgrow detected only 15 positive cultures. Of the 18 patients with gonorrhea, 11 exhibited reactive serum (agglutination of the latex particles). In the total population, 64% of the patients had nonreactive serum (no agglutination) and negative cultures; 25% had reactive serum and negative cultures. When this latter group was subdivided on the basis of race, blacks and Latin Americans were found to have a higher incidence of reactive serum with a corresponding negative culture than was found in whites. Patients who were originally culture positive and nonreactive in the Gonosticon Test were retested; three out of four patients retested within 6 to 11 days after the initial screening had converted to a positive Gonosticon test.
Improved Rapid Plate Method for the Isolation of Bacteriophages from Lysogenic Bacteria
Authors: Parisi Joseph T. , Talbot Henry W.
Published: December 2020

A modification of a recently reported rapid plate method for the isolation of bacteriophages from lysogenic bacteria is described. The velveteen replica plate technique was used for inoculation of mitomycin C-induced colonies onto agar plates, and tetrazolium chloride was used to enhance detection of phage activity on replicated indicator plates.
Modification of Tergitol-7 Agar for Differentiation of Hydrogen Sulfide-Producing Colonies
Authors: Hinds D. B. , Howard A. T.
Published: December 2020

The indication of H
2
S production by a modified Tergitol-7 agar combines the advantages of both selective and differential enteric media to provide a medium with broader coverage.
Automated Count and Size Evaluation of Colonies of Bacteria Grown in a Zonal Concentration Gradient of Antimicrobial Agent
Authors: Yourassowsky E. , Schoutens E.
Published: December 2020

The quantitative study (counting and size and surface evaluation of bacterial colonies) of the activity of an antimicrobial agent against a microbial population growing in solid medium can be performed by an electronic image analyzer. The Zeiss Micro-Videomat allowed the detection of even slight antimicrobial effects, which would be difficult to detect by colony counting alone and would escape the manual procedures of observation. The potential of the new method of investigation was illustrated by the examination of
Staphylococcus aureus
inhibition zones produced by disks of penicillin G and sulfadiazine.
Isolation of Ureolytic
Peptostreptococcus productus
from Feces Using Defined Medium; Failure of Common Urease Tests
Authors: Varel Vincent H. , Bryant M. P. , Holdeman L. V. , Moore W. E. C.
Published: December 2020

Colony counts of fecal samples from three persons, obtained by using a chemically defined anaerobic roll-tube medium (containing glucose, maltose, glycerol, minerals, hemin, B-vitamins, methionine, volatile fatty acids, sulfide, bicarbonate, agar, carbon dioxide (gas phase), and 1 mM NH
4
+
as main nitrogen source), averaged 60% of the 8.8 × 10
10
bacteria per g obtained when 0.2% Trypticase and 0.05% yeast extract were added to the otherwise identical medium. When 0.2% vitamin-free Casitone replaced Trypticase and yeast extract, counts were 94% those of the more complex medium. When urea-nitrogen was added to the defined medium as the main nitrogen source in place of NH
4
+
, counts of relatively large colonies averaged 1.0 × 10
9
per g of feces from five persons—1.1% of counts on the medium containing Trypticase and yeast extract. All of the organisms from the large colonies in the urea roll tubes were morphologically similar, and all six representative strains isolated were identified as urease-forming
Peptostreptococcus productus
, a species not previously known to produce urease. Ureolytic strains of
Selenomonas ruminantium
and
P. productus
were negative for urease activity in three assay media when inocula were from media containing complex nitrogen sources. The study documents that
P. productus
is the most numerous ureolytic species so far found in human feces and suggests that NH
4
+
and more complex organic nitrogen sources strongly repress its production of urease. The study also indicates the efficacy of chemically defined media for direct selective isolation of nutritional groups of bacteria from feces.
Evaluation of the Minitek System for Identification of
Enterobacteriaceae
Authors: Kiehn T. E. , Brennan K. , Ellner P. D.
Published: December 2020

Clinical isolates (869) and stock cultures (35) of
Enterobacteriaceae
were tested in parallel with the Minitek and conventional systems. The Minitek correctly identified 822 of 904 cultures. When a deoxyribonuclease plate was inoculated along with the Minitek, it was possible to speciate
Enterobacteriaceae
within 24 h. False-positive hydrogen sulfide reactions were the major fault with this system. Reactions were clear-cut and easy for technologists to read.
Carotenoid Pigments of
Mycobacterium kansasii
Authors: David Hugo L.
Published: December 2020

Partitioned between aqueous methanol and petroleum ether, the unsaponifiable pigments of
Mycobacterium kansasii
were all epiphasic. Thin-layer chromatography of these carotenoids showed that
M. kansasii
formed at least nine pigments. These pigments were identified by their chromatographic properties and spectral characteristics as phytoene, ζ-carotene, neurosporene, lycopene, leprotene, γ-carotene, δ-carotene, α-carotene, and β-carotene. Three additional pigmented spots on thin-layer chromatography found in trace amounts were possibly degradation products of the major carotenoids.
Acetamide Agar for Differentiation of Nonfermentative Bacteria
Authors: Oberhofer Thomas R. , Rowen Joyce W.
Published: December 2020

An acetamide agar medium is described for use in the differentiation of nonfermentative gram-negative bacteria. With few exceptions, indicator reactions were rapid, intense, and clear-cut.
Micro Cell Culture Method for Isolation of
Chlamydia trachomatis
Authors: McComb Dorothy E. , Puzniak Constance I.
Published: December 2020

Presterilized mictotiter plates (96 wells) with BHK-21 cells on 5-mm cover slips were successfully used for cell culture isolation of trachoma from 15 infected conjunctival scrapings.
Rapid Methods for Biochemical Testing of Anaerobic Bacteria
Authors: Schreckenberger Paul C. , Blazevic Donna J.
Published: December 2020

Rapid biochemical tests for nitrate, indole, gelatin, starch, esculin, and
o
-nitrophenyl-β-D-galactopyranoside were performed on 112 strains of anaerobic bacteria. All tests were incubated under aerobic conditions, and results were recorded within 4 h. The tests for nitrate, indole, and starch showed a 95% or greater correlation when compared to the standard biochemical tests. Tests for esculin and gelatin showed an agreement of 86 and 77%, respectively. PathoTec test strips for nitrate, indole, esculin,
o
-nitrophenyl-β-D-galactopyranoside, Voges-Proskauer, and urease were also tested and showed encouraging results.
Evaluation of the BBL Minitek System for the Identification of
Enterobacteriaceae
Authors: Hansen S. L. , Hardesty D. R. , Myers B. M.
Published: December 2020

Thirty-one different substrate disks were tested in parallel with comparable, prepared media (BBL) against a minimum of 300 cultures of
Enterobacteriaceae
. An overall correlation of 98% was observed with all the disks tested. In addition, the system was used to identify 461 fresh isolates of
Enterobacteriaceae
in parallel with conventional media using the schema used at the Veterans Administration Hospital, Baltimore. An overall correlation of 97% was observed. Minitek is a time and space saving system. It is accurate and easily adapted to the clinical laboratory. A wide variety of substrates are available, allowing most laboratories to use their own schema. The long shelf life of most disks is a definite advantage.
Factors That Influence Microbial Contamination of Fluids Associated with Hemodialysis Machines
Authors: Favero Martin S. , Carson Loretta A. , Bond Walter W. , Petersen Norman J.
Published: December 2020

Studies were conducted on the microbiological quality of fluids associated with different types of dialysis systems located in six dialysis centers and 14 homes. Included were (i) single-pass systems employing either parallel flow (Kiil or Gambro) or capillary cartridge dialyzers and (ii) recirculating single-pass and batch recirculating systems using coil dialyzers. Microbiological assays were performed on the water used to prepare dialysis fluid, the concentrated dialysate, and either pre- and postdialyzer dialysate (single-pass systems) or the dialysate contained in storage reservoirs and recirculating cannisters (recirculating systems). The levels of microbial contamination consisting of gram-negative bacteria were directly related to the type of dialysis system, method of water treatment, distribution system, and in some instances, the type of dialyzer. Recirculating single-pass and batch recirculating systems consistently contained significantly higher levels of contamination than single-pass systems. These results were directly related to the design of recirculating systems which permits carbon- and nitrogen-containing waste products dialyzed from the patient to accumulate, be used as nutrients by microorganisms, and subsequently allow for 2- to 4-log increases in contamination levels during a dialysis treatment. In contrast, levels of contamination in single-pass machines were related more to the quality of the water used to prepare dialysis fluid and the adequacy of cleaning and disinfection procedures than to the design of the system.
Fluorescent Antibody Study of the Gram-Positive Anaerobic Cocci
Authors: Porschen Richard K. , Spaulding Earle H.
Published: December 2020

Fluorescent antibody conjugates were prepared from five species of anaerobic cocci commonly isolated from human infections. When tested with homologous and heterologous cells these conjugates were found to be highly specific. There was no evidence of a common genus antigen.
Peptococcus magnus
conjugates detected a species-specific antigen; cross-reactions with
Peptostreptococcus anaerobius
were readily eliminated by absorption. The conjugates from
Peptococcus asaccharolyticus, Peptococcus prevotii, Peptostreptococcus, anaerobius
, and
Peptostreptococcus intermedius
displayed a high degree of strain specificity. Occasional cross-reactions were detected with homologous strains, suggesting the presence of common antigens, but no attempt was made to determine the number of different serotypes in these species.
Membrane Concentration of Infectious Bovine Rhinotracheitis Virus from Water
Authors: Tschider S. R. , Berryhill D. L. , Schipper I. A.
Published: December 2020

A membrane adsorption procedure was used to concentrate infectious bovine rhinotracheitis virus from 1-liter quantities of distilled water. Cellulose nitrate membrane filters (0.45-μm pore size) efficiently adsorbed this herpesvirus from water, and virus was recovered from the membrane by elution with 10 ml of fetal calf serum during sonic treatment. The average recovery rate was 70%.
Ecological Application of Antibiotics as Respiratory Inhibitors of Bacterial Populations
Authors: Yetka J. E. , Wiebe W. J.
Published: December 2020

Two terregenous and four marine bacterial isolates were treated with six antibiotics and antibiotic combinations. Comparisons made between responses of cells in early and late logarithmic and stationary growth phases indicated variable sensitivity to the agents. Bacteria in stationary and late log-phase cultures exhibited the greatest resistance, whereas the early log-phase cells exhibited greatest antibiotic susceptibility. We conclude that the tested antibiotics cannot be used for ecological purposes to delineate bacterial respiration in mixed microbial communities.
Evaluation of Selective Media for Enumeration of Group D Streptococci in Bovine Feces
Authors: Switzer R. E. , Evans James B.
Published: December 2020

Eight commercially available selective media were evaluated by the membrane filter technique. Enterococcosel broth (BBL) consistently gave the best recovery of group D streptococci, particularly of
Streptococcus bovis
.
Comparison of the Sphingolipid Content of Rumen
Bacteroides
Species
Authors: Kunsman Joseph E. , Caldwell Daniel R.
Published: December 2020

Ten strains of
Bacteroides ruminicola
were found to contain phosphosphingolipids. Four strains of
Bacteroides amylophilus
and one strain each of
Bacteroides succinogenes
and
Bacteroides
sp. were devoid of phosphosphingolipids.
Toxigenic Aspergilli and Penicillia Isolated from Aged, Cured Meats
Authors: Wu M. T. , Ayres J. C. , Koehler P. E.
Published: December 2020

Eighty-nine cultures of
Aspergillus
and 54 cultures of
Penicillium
isolated from aged, cured meats were tested for toxicity to chicken embryos. Two of 22 isolates of
A. ruber
, 5 of 28
A. repens
, 2 of 12
A. sydowi
, 1 of 12
A. restrictus
, 2 of 7
A. amstelodami
, 1 of 2
A. chevalieri
, and an
A. fumigatus
isolate exhibited toxicity. Similarly, 2 of 15 isolates of
P. expansum
, 1 of 3
P. notatum
, 1 of 2
P. brevi-compactum
, and 1 of 8
Penicillium
spp. were found to be the most toxic. Among these fungi, the chloroform extract from the growth of an
A. sydowi
isolate showed the greatest toxicity. There was no direct or indirect evidence that aged, cured meats contain toxic metabolites.
Growth of
Pseudomonas
C on C
1
Compounds: Continuous Culture
Authors: Battat E. , Goldberg I. , Mateles R. I.
Published: December 2020

Pseudomonas
C was grown in continuous culture on methanol, formaldehyde, or formate as sole carbon source. On methanol μ

max

= 0.49/h and yield constant (
Y
) = 0.54; on formaldehyde and on unsupplemented media, μ

max

was about 0.2/h and
Y
was 0.15, whereas addition of
p
-aminobenzoic acid, folic acid, serine, or glycine to the medium raised
Y
to about 0.26 to 0.29, and addition of
p
-aminobenzoic acid, folic acid, serine, nicotinamide adenine dinucleotide, and Tween 80 raised the yield to 0.35. On formate and on unsupplemented media, μ

max

= 0.2/h and
Y
= 0.02, whereas addition of 0.1 mM
p
-aminobenzoic acid increased μ

max

to about 0.47 and
Y
to about 0.23. At low cell concentrations or growth rates a beneficial effect of CO
2
was observed. Formaldehyde or formate, when added together with methanol, were utilized simultaneously with the methanol.
Isolation of Thermophilic Fungi From Snuff
Authors: Tansey Michael R.
Published: December 2020

Fourteen samples of retail purchases of snuff were examined for the presence of viable thermophilic fungi; four species were found.
Development of a Simple Method for Concentrating Enteroviruses from Oysters
Authors: Sobsey Mark D. , Wallis Craig , Melnick Joseph L.
Published: December 2020

The development of a simple method for concentrating enteroviruses from oysters is described. In this method viruses in homogenized oyster tissues are efficiently adsorbed to oyster solids at pH 5.5 and low salt concentration. After low-speed centrifugation, the supernatant is discarded and viruses are eluted from the sedimented oyster solids by resuspending them in pH 3.5 glycine-buffered saline. The solids are then removed by low-speed centrifugation, and the virus-containing supernatant is filtered through a 0.2-μm porosity filter to remove bacteria and other small particulates without removing viruses. The virus-containing filtrate is then concentrated to a volume of a few milliliters by ultrafiltration, and the concentrate obtained is inoculated directly into cell cultures for virus assay. When tested with pools of oysters experimentally contaminated with small amounts of different enteroviruses, virus recovery efficiency averaged 63%.
β-Galactosidase of
Propionibacterium shermanii
Authors: Hartley J. C. , Vedamuthu E. R.
Published: December 2020

Ten strains of
Propionibacterium shermanii
were tested for β-galactosidase (β-gal) activity. Of these ten strains, five yielded enhanced enzyme activity when cell suspensions were treated with toluene-acetone; on solvent treatment, the remaining five lost a considerable portion of the activity found in whole-cell suspensions. By using a strain yielding decreased activity upon solvent treatment, explanations for the loss in activity were sought through assays for possible alternative β-galactoside utilization mechanisms. When this strain was assayed for β-D-phosphogalactoside galactohydrolase by using orthonitrophenyl-β-D-galactopyranoside-6-PO
4
as substrate, the activity was either lower or indifferent as compared with β-gal activity determined simultaneously. Cell suspensions of
P. shermanii
7 and 22 (strains chosen for further work) grown separately on the individual substrates (lactose, glucose, galactose, and sodium lactate) did not show significant differences in β-gal activity. Optimal temperature for β-gal activity in untreated and toluene-acetone-treated cell suspensions of strain 7 was 52 C. With strain 22, of the temperatures tested, maximal activity in untreated cell suspensions was noted at 58 C and with solvent-treated cells at 32 C. In the cell-free extract (CFE) system, both strains exhibited maximal activity at 52 C. Optimal pH for untreated and solvent-treated cell suspensions of both strains was around 7.5. In the
P. shermanii
22 CFE system, maximal activity occurred at pH 7.0; pH had very little effect on enzyme activity in
P. shermanii
7 CFE. Sodium or potassium phosphate buffers in the assay system yielded the best activity. In the CFE system of these two strains, Mn
2+
was definitely stimulatory, but in untreated and solvent-treated cell systems of these strains presence or absence of Mn
2+
in the assay system had variable effects on enzyme activity. Maximal β-gal activity was noted in
P. shermanii
7 cells harvested after 28 h of growth at 32 C in sodium lactate broth. Sulfhydryl-group blocking agents inhibited enzyme activity in
P. shermanii
22 CFE; the inhibition was partly reversed by dithiothreitol.
Plaque Production by Arboviruses in Singh's
Aedes albopictus
Cells
Authors: Yunker C. E. , Cory J.
Published: December 2020

We report plaquing tests of 124 virus strains, mostly arboviruses of 21 serological groups, in Singh's line of
Aedes albopictus
cells. Thirty of these plaqued; all were arboviruses of six groups and were known or presumed to be mosquito borne. Failing to plaque were 86 strains of arboviruses, mostly tick borne, two strains of insect pathogens, and six animal viruses not classified as arboviruses. Among mosquito-borne agents, plaquing ability appeared related to serological classification. California group and most A-group viruses failed to plaque, but nearly all members of B and Bunyamwera groups readily plaqued. Within serological group B, 14 of 16 mosquito-borne agents plaqued, but none of 13 tick-borne or vector-unassociated viruses did so. Some implications of these results for recognition and classification of arboviruses are discussed.
Collagenolytic Activity of Some Marine Bacteria
Authors: Merkel Joseph R. , Dreisbach Joseph H. , Ziegler Henry B.
Published: December 2020

Reconstituted, acid-extracted collagen was used to prepare a medium to screen proteolytic marine bacteria for their ability to elaborate collagenolytic enzymes. The medium was resistant to solubilization by trypsin, hyaluronidase, chondroitinase ABC, and various marine proteinases, but was readily hydrolyzed by commercial
Clostridium
collagenases. Eighty-seven marine isolates collected in the vicinity of Bermuda, Oahu (Hawaii), and Stone Harbor and Cape May, N.J., were screened. Approximately 44% of the isolates were capable of elaborating enzymes that hydrolyzed reconstituted collagen gels. Several cultures produced collagenolytic enzymes only when grown in the presence of collagen or degradation products of collagen, and with very few exceptions the presence of collagen in the medium greatly enhanced collagenolytic enzyme production. The enzymes from a collagenolytic Bermuda marine isolate were studied in more detail to illustrate that the enzymes capable of hydrolyzing reconstituted collagen were separable from nonspecific proteinases by zone electrophoresis and that these enzymes were true collagenases by virtue of their ability to hydrolyze native bovine Achilles' tendon obtained from three different sources.
Protozoa as Agents Responsible for the Decline of
Xanthomonas campestris
in Soil
Authors: Habte Mitiku , Alexander Martin
Published: December 2020

A streptomycin-resistant mutant of
Xanthomonas campestris
was used to assess the persistence of the plant pathogen in soil and the changes in populations that might be important for its survival. In soil into which large numbers of the organism were introduced, a marked decline in its abundance occurred, but after about 1 week its population density reached a level of about 10
5
and did not continue to fall during the test period. No such marked decline was evident in sterile soil inoculated with
X. campestris
. The bacterium did not lose viability if starved for carbon or inorganic nitrogen. Although abundant in soil, the numbers of propagules capable of producing antibiotics or lytic enzymes active against
X. campestris
did not increase coincident with the pathogen's decline, and no increase in tartrate-extractable toxins was observed. Neither bdellovibrios nor bacteriophages active against the xanthomonad were found in the soil, but a marked increase in the frequency of protozoa paralleled the phase of rapid diminution in the
X. campestris
population. In actidione-treated soil, in which protozoan activity was severely limited, the high cell density of the pathogen was maintained. On the basis of these data, it is concluded that predation by protozoa is responsible for the abrupt fall in frequency of the bacterium in natural soil.
Influence of Environmental Stress on Enumeration of Indicator Bacteria from Natural Waters
Authors: Bissonnette G. K. , Jezeski J. J. , McFeters G. A. , Stuart D. G.
Published: December 2020

The problems associated with recovery of pure cultures of
Escherichia coli
and
Streptococcus faecalis
from stream environments were examined utilizing membrane filter chambers. It was observed that upon exposure to the aquatic environment a significant proportion of cells lost their ability to produce colonies on a selective medium, yet retained this capability on a nutritionally rich, nonselective medium. Discrepancies in colony-forming units between nonselective and selective media indicated that a substantial portion of bacterial cells may become physiologically injured due to the environmental stress imposed by the aquatic environment. The extent of injury was observed to vary considerably among the eight different stream environments, since the amount of injury was not uniform for all types of water environments examined. It was observed that the injury acquired by a population of
E. coli
, during exposure to the aquatic environment, could be rapidly repaired in a nutritionally rich, nonselective medium. As the injured population of cells was exposed to the rich, nonselective broth, increasing proportions of cells were able to repair themselves such that they became insensitive to inhibitory agents in selective media.
Assay for Lipolytic and Proteolytic Activity Using Marine Substrates
Authors: Tom Raymond A. , Crisan Eli V.
Published: December 2020

Nondestructive assay procedures for determining microbial lipolytic and proteolytic activity on marine substrates were developed and tested with 287 isolates of bacteria, filamentous fungi, and yeasts. A definite substrate specificity was noted when the enzymatic activities on marine and nonmarine substrates was compared. Of 170 lipolytic isolates, 14 were only active on menhaden oil, 11 could hydrolyze menhaden oil and Tween 80 and/or tributyrin, and 145 isolates could only hydrolyze one or both of the nonmarine lipids. Of the 198 proteolytic isolates, 10 were specific for codfish extract, 152 were active against the marine substrate plus casein and/or gelatin, and 36 were specific for nonmarine substrates.
Influence of Modified Atmosphere Storage on Aflatoxin Production in High Moisture Corn
Authors: Wilson David M. , Jay Edward
Published: December 2020

Samples of freshly harvested corn and remoistened corn were inoculated with
Aspergillus flavus
and stored for 4 weeks at about 27 C in air and three modified atmospheres. Aflatoxins and fat acidity were determined weekly. Corn stored in the modified atmospheres did not accumulate over 15 μg of aflatoxin B
1
per kg and 20 μg of total aflatoxins per kg. Corn from the high CO
2
treatment (61.7% CO
2
, 8.7% O
2
, and 29.6% N
2
) was visibly molded at 4 weeks and had a higher fat acidity than the other treatments. In the N
2
(99.7% N
2
and 0.3% O
2
) and controlled atmosphere (13.5% CO
2
, 0.5% O
2
, 84.8% N
2
) treatments, a fermentation-like odor was detected. When the corn was removed from the modified atmospheres it deteriorated rapidly and was soon contaminated with aflatoxins.
The Moroccan Food Snail,
Helix aspersa
, as a Source of
Salmonella
Authors: Andrews Wallace H. , Wilson Clyde R. , Romero Aida , Poelma Paul L.
Published: December 2020

A total of 270 samples, nine lots of 30 samples each, of imported Moroccan food snails was examined for the presence of
Salmonella
. Eighty-four samples (an overall incidence of 31.11%) and all nine lots contained
Salmonella
. No significant difference (
P
> 0.25) in the number of positive samples was observed by using either selenite cystine broth or tetrathionate broth when the samples had been pre-enriched in lactose broth. When used as direct selective enrichments with samples not pre-enriched in lactose broth, tetrathionate broth was significantly (
P
< 0.05) more productive than selenite cystine broth. The overall detection of
Salmonella
-positive samples by direct enrichment was significantly greater (
P
< 0.001) than by pre-enrichment. A variety of uncommon serotypes representative of several somatic groups was isolated. This study reports the occurrence and incidence, and the concomitant human health potential, of
Salmonella
in one species of live, imported food snails.
Bacterial Survival in Laundered Fabrics
Authors: Walter William G. , Schillinger John E.
Published: December 2020

Bacterial survival was determined in linens (i) inoculated with
Staphylococcus aureus
(ii), taken from hospital isolation patients' beds, and (iii) used by students in their homes. Two different washers using temperatures of 38, 49, 54 and 60 C, respectively, for different times were employed along with a commercial tumbler dryer. Findings, after macerating the linens in a Waring blender and enumerating on nonselective media, indicate that acceptable levels of survivors can be achieved in motel and hotel linens by an 8- to 10-min wash cycle at 54 C followed by adequate drying. However, it is recommended that a wash cycle with 60 C for 10 to 13 min be employed for linens in health care factilities. The microbial significance of various laundering practices is discussed.
Bacterial Metabolism of Arylsulfonates: Role of
meta
Cleavage in Benzene Sulfonate Oxidation by
Pseudomonas testosteroni
Authors: Ripin Marilyn J. , Cook Thomas M. , Noon Kerry F. , Stark Leonard E.
Published: December 2020

Pseudomonas testosteroni
H-8 oxidizes certain lower alkylbenzene sulfonates at rates inversely related to the length of the alkyl group. Appreciable Q(O)
2
values were observed for benzene sulfonate (BS), toluene sulfonate (TS), and ethylbenzene sulfonate (EBS), but not for propylbenzene sulfonate (PS) and higher homologues. Catechol oxidation was catalyzed by a constitutive catechol-2,3-oxygenase (EC 1.99.2.a). Yellow
meta
cleavage products accumulated when BS-grown cells were exposed to catechol, 4-methylcatechol, 3-methylcatechol, EBS and PS, but not BS or TS. Traces of a yellow metabolite (probably 2-hydroxymuconic semialdehyde) were detectable during growth on BS. PS completely inhibited growth on BS, but not on L-leucine or nutrient broth. Also, PS antagonized respiration on BS and catechol, but not glutamate, the extent of inhibition being directly related to PS concentration. Formation of a
meta
cleavage product from PS, and inhibition of catechol oxidation by PS, suggested that the actual inhibitor may not be PS itself, but a metabolite.
Chondroitinase-Producing Bacteria in Natural Habitats
Authors: Kitamikado Manabu , Lee Young-Zoon
Published: December 2020

A search was undertaken for bacteria which degrade chondroitin sulfate in nature and to find bacteria with a usefully high rate of chondroitinase (ChSase) productivity. First, 253 ChSase-producing bacteria were obtained from aquatic and land environments in Japan by aerobic and anaerobic screening methods. Identification according to
Bergey's Manual of Determinative Bacteriology
or Bain and Shewan (1968) permitted assignment of the majority of the isolates to seven genera,
Aeromonas, Vibrio, Flavobacterium, Beneckea, Proteus, Micrococcus
, and
Arthrobacter
. Next, ChSase productivities of all the isolates were compared with those of two established ChSase-producing stock strains,
Proteus vulgaris
NCTC 4636 and
Flavobacterium heparinum
ATCC 13125. As a result, special attention was given to production by a strain of
Aeromonas
sp. of large quantities of extracellular ChSase-AC. None of the isolates from the current study displayed significant ChSase-ABC productivity. Finally, ChSase-AC was prepared from the culture fluid of the
Aeromonas
strain by fractional precipitation with ammonium sulfate, chromatography on phospho-cellulose and diethylaminoethyl-cellulose, and gel filtration on Sephadex G-200. It was concluded that the
Aeromonas
strain may represent a profitable source of the enzyme ChSase-AC.
Action of Water in Depressing Acetylene Reduction by Detached Nodules
Authors: Van Straten J. , Schmidt E. L.
Published: December 2020

Adverse effects of water on acetylene reduction by detached soybean root nodules could not be attributed to ethanol formation, but apparently were associated with nodule tissue damage caused by detachment. Intact nodules were not affected by moisture.
Toxigenic Thermophilic and Thermotolerant Fungi
Authors: Davis N. D. , Wagener R. E. , Morgan-Jones G. , Diener U.L.
Published: December 2020

Twenty-three isolates of fungi, representing 13 thermophilic and thermotolerant species, were bioassayed for toxigenicity to brine shrimp, chicken embryos, and rats. Thirteen isolates representing nine genera were highly toxic to at least two of the three systems. Seven additional isolates of five genera were slightly toxic.
Biohazards Assessment in Large-Scale Zonal Centrifugation
Authors: Baldwin C. L. , Lemp J. F. , Barbeito M. S.
Published: December 2020

A study was conducted to determine the biohazards associated with use of the large-scale zonal centrifuge for purification of moderate risk oncogenic viruses. To safely and conveniently assess the hazard, coliphage T
3
was substituted for the virus in a typical processing procedure performed in a National Cancer Institute contract laboratory. Risk of personnel exposure was found to be minimal during optimal operation but definite potential for virus release from a number of centrifuge components during mechanical malfunction was shown by assay of surface, liquid, and air samples collected during the processing. High concentration of phage was detected in the turbine air exhaust and the seal coolant system when faulty seals were employed. The simulant virus was also found on both centrifuge chamber interior and rotor surfaces.