bluuebunny/crossref_metadata_2025 huggingface dataset:
Extracellular Deoxyribonuclease Production by Anaerobic Bacteria
Authors: Porschen Richard K. , Sonntag Sandra
Published: December 2020

The production of extracellular deoxyribonuclease was examined with anaerobic organisms isolated from clinical specimens. Nuclease activity was extraordinarily common. All strains of
Fusobacterium
, including eight species, as well as
Bacteroides fragilis
and
B. melaninogenicus
, displayed enzyme activity. Whereas the gram-positive bacteria were generally less productive, all strains of
Clostridium perfringens, Peptostreptococcus intermedius
, and
P. anaerobius
specifically produced deoxyribonuclease. The test is taxonomically valuable, particularly in the characterization of gram-positive cocci, since a deoxyribonuclease-producing coccus indicates
P. intermedius
or
P. anaerobius
. Additionally, possession of the enzyme may prove to be a useful correlate of the potential pathogenicity of anaerobes.
Method for Isolation and Selection of Temperature-Sensitive Mutants of Herpes Simplex Virus
Authors: Manservigi Roberto
Published: December 2020

A method for induction and selection of temperature-sensitive mutants of herpes simplex virus is presented. After the infected cells were treated with 5-bromodeoxyuridine, the virus was extracted by repeated freezing and thawing and cloned in microcultures which were then incubated at permissive temperature until viral plaques appeared. The microcultures were then replicated at nonpermissive temperature. Clones not forming plaques in these latter were further purified and examined for temperature-sensitive characteristics. Viral clones mutated in plaque-forming ability or in yield were obtained and preliminarily characterized.
NYC Medium for Simultaneous Isolation of
Neisseria gonorrhoeae
, Large-Colony Mycoplasmas, and T-Mycoplasmas
Authors: Faur Yvonne C. , Weisburd Martin H. , Wilson Marion E. , May Paul S.
Published: December 2020

NYC medium, primarily designed for isolation of pathogenic
Neisseria
, also readily supports the growth of large-colony mycoplasmas and T-mycoplasmas. When compared with A-3 agar medium and PPLO agar in clinical field trials, NYC medium performed equally as well as these mycoplasma-specific media in providing recovery of
Mycoplasma
species from female genital specimens. The transparent, highly-selective NYC medium permits direct, microscopic observation and presumptive identification of mycoplasmas, as well as
Neisseria gonorrhoeae
, without interference from contaminating saprophytes. As a single medium it can therefore be doubly useful in the diagnosis of gonorrhea and in the recognition of active or asymptomatic mycoplasma infections. Used in gonorrhea screening programs, the medium can be valuable in establishing the frequency of association of mycoplasmas with urogenital tract infection.
Persistence of Bacteriophages in Experimentally Infected Cell Cultures
Authors: Orr Henry C. , Probst Peter G. , Littlejohn Dewitt C. , Chu Fred C. , Petricciani John C.
Published: December 2020

A bacteriophage, isolated from a live measles vaccine and designated ϕV-1
L
, was intentionally introduced into cell culture systems. The bacterial virus persisted in the cell cultures after daily medium changes and trypsinization, and in cell lysates prepared by freezing and thawing. The results suggest that phages contaminating cell cultures may be carried over into the final product during the manufacture of viral vaccines.
Identification of Yeasts From the Suwannee River Florida Estuary
Authors: Lazarus C. R. , Koburger J. A.
Published: December 2020

The yeast flora of the Suwannee River estuary in Florida has been studied. The predominant genera were
Candida
and
Rhodotorula
; however, the yeast most frequently isolated was
Cryptococcus laurentii
. Nine ascosporogenous species were isolated, with
Hansenula saturnus
predominating. The salinity range of the sediments was 0.4 to 20.6%; in the estuary water, 0.07 to 0.25%; and in the open Gulf of Mexico, 18 to 20%.
Evaluation of Porcelain Cup Soil Water Samplers for Bacteriological Sampling
Authors: Dazzo Frank B. , Rothwell Donald F.
Published: December 2020

The validity of obtaining soil water for fecal coliform analyses by porcelain cup soil water samplers was examined. Numbers from samples of manure slurry drawn through porcelain cups were reduced 100- to 10,000,000-fold compared to numbers obtained from the external manure slurry, and 65% of the cups yielded coliform-free samples. Fecal coliforms adsorbed to cups apparently were released, thus influencing the counts of subsequent samples. Fecal coliforms persisted in soil water samplers buried in soil and thus could significantly influence the coliform counts of water samples obtained a month later. These studies indicate that porcelain cup soil water samplers do not yield valid water samples for fecal coliform analyses.
Improved Techniques for Staining and Enumerating Focus Formation in Viral Infectivity Assays
Authors: Self Donnie J. , Pettiss Katherine F. , Bigner Darell D.
Published: December 2020

Improved techniques consisting of glutaraldehyde fixation, Giemsa staining, and colony counter enumeration of foci in viral infectivity assays were compared to microscope scanning and lantern slide projection methods. These techniques broadened the scope of application to potentially hazardous viruses and increased the efficiency of assaying.
Use of Immunoperoxidase for the Rapid Identification of Human Myxoviruses and Paramyxoviruses in Tissue Culture
Authors: Benjamin Denis R. , Ray C. George
Published: December 2020

The immunoperoxidase method, using commercially available antisera, was compared with standard virological methods for the identification and typing of 77 isolates of human myxoviruses and paramyxoviruses. Results of typing using neutralization tests and the immunoperoxidase technique were identical for 76 of the 77 isolates. With the immunoperoxidase method there was one false negative reaction, but no false positive reactions. Cross-reactivity between influenza A (soluble) and A
2
/HK antisera with influenza A isolates was noted, but did not interfere with the interpretation of results. It is concluded that the immunoperoxidase method is ideally suited for the rapid identification and typing of common human respiratory viruses on a routine basis. It offers a number of decided advantages over both immunofluorescence and standard virological methods.
Comparison of Rapid Methods for Analysis of Bacterial Fatty Acids
Authors: Moss C. Wayne , Lambert M. A. , Merwin W. H.
Published: December 2020

When rapid gas-liquid chromatography methods for determination of bacterial fatty acids were compared, results showed that saponification was required for total fatty acid analysis. Transesterification with boron-trihalide reagents (BF
3
-CH
3
OH, BCl
3
-CH
3
OH) caused extensive degradation of cyclopropane acids and was less effective than saponification in releasing cellular hydroxy fatty acids. Digestion of cells with tetramethylammonium hydroxide was unsatisfactory because of extraneous gas-liquid chromatography peaks and because of lower recovery of branched-chain and hydroxy fatty acids. A simple, rapid saponification procedure which can be used for total cellular fatty acid analysis of freshly grown cells is described.
Evaluation of the Indirect Fluorescent-Antibody Technique for Identification of
Naegleria
Species
Authors: De Jonckheere J. , Van Dijck P. , van de Voorde H.
Published: December 2020

The indirect fluorescent-antibody technique was used to assess a rapid method for identification of amoebae belonging to the genus
Naegleria
. Thirty-eight
Naegleria
and eight other limax amoeba strains were examined by using one
N. gruberi
and two
N. fowleri
antisera. All pathogenic
Naegleriae
, most of which originated from fatal cases of primary amoebic meningo-encephalitis, were identified as belonging to the
fowleri
species. Most of the
N. gruberi
strains showed irregular fluorescence. Other limax amoebae, such as
Vahlkampfia, Acanthamoeba, Hartmannella
, and
Schizopyrenus
sp. gave negative responses with the prepared antisera. The indirect fluorescent-antibody technique allows the identification of
N. fowleri
in a mixed culture of both
N. fowleri
and
N. gruberi
strains. Twenty-two
Naegleria
isolated from a suspected stream, other surface waters, and muddy soil could be excluded from the
fowleri
species with the indirect fluorescent-antibody technique. The results obtained demonstrate that this immunological technique is a valid method for the rapid identification of
N. fowleri
trophozoites.
Growth Rates of a Pseudomonad on 2,4-Dichlorophenoxyacetic Acid and 2,4-Dichlorophenol
Authors: Tyler J. E. , Finn R. K.
Published: December 2020

The growth of a pseudomonad on 2,4-D (2,4-dichlorophenoxyacetic acid) and 2,4-DCP (2,4-dichlorophenol) was studied in batch and continuous culture. The optimum growth rate using 2,4-D was 0.14/h at 25 C in a pH range from 6.2 to 6.9. Highest specific growth rate using 2,4-DCP was 0.12/h at 25 C in a pH range from 7.1 to 7.8. Growth was strongly inhibited by 2,4-DCP above a concentration of 25 mg/liter whereas no appreciable inhibition was observed with 2,4-D at concentrations up to 2,000 mg per liter. Growth on 2,4-DCP was described by Monod kinetics at subinhibitory concentrations but the inhibition by 2,4-DCP exhibited an unusual linear response to substrate concentration, and did not fit a model based on noncompetitive inhibition. The lag phase of batch cultures was found to depend on both 2,4-DCP concentration and prior adaptation of the inoculum. A study such as this on the kinetics of growth on related substrates may be useful as a method of finding the rate-limiting step in a metabolic sequence.
Hydrophobic Grid-Membrane Filters: New Approach to Microbiological Enumeration
Authors: Sharpe A. N. , Michaud G. L.
Published: December 2020

A square grid pattern, printed in hydrophobic material on conventional membrane filters, subdivided the surface into a plurality of areas. This separated colonies from one another and prevented lateral growth, spreading, and confluence. Very high colony-packing densities were achieved (2,500/in
2
; ca. 1.61 � 10
5
/cm
2
) reducing the need to dilute samples. Recovery of organisms was better than on conventional filters, particularly at high inoculum levels. At the same time, visibility of normally pale or diffuse colonies was improved, since colonies grew upwards instead of sideways, and counting was facilitated because colonies grew in orderly arrays.
Simplified Approach to Identification of Aerobic Actinomycetes by Thin-Layer Chromatography
Authors: Staneck Joseph L. , Roberts Glenn D.
Published: December 2020

A system has been developed for the identification of aerobic actinomycetes in the clinical laboratory based on analysis of whole cells for diaminopimelic acid and carbohydrates and on the ability of the organism to decompose casein, tyrosine, and xanthine media. The whole-cell analyses were performed by a simple thin-layer chromatographic procedure that is described. Eighteen reference cultures were correctly identified and, subsequently, 35 isolates from clinical material were grouped by using this system. The method is well suited for use in routine clinical laboratories.
Development of Methods for Detecting Viruses in Solid Waste Landfill Leachates
Authors: Sobsey Mark D. , Wallis Craig , Melnick Joseph L.
Published: December 2020

Methods were developed for detecting and concentrating enteric viruses in municipal solid waste landfill leachates. Poliovirus added to a leachate was not readily detectable, possibly because the virus was adsorbed to the leachate particulates. The masking effects associated with suspended solids in the leachate were overcome by adding a final 0.1 M sodium (tetra)ethylenediaminetetraacetate concentration to the leachate. A sodium (tetra)ethylenediaminetetraacetate-treated leachate could be clarified by filtration at pH 8.0 without a loss of virus. The clarified and sodium (tetra)ethylenediaminetetraacetate-treated leachate contained interfering materials of an anionic nature which prevented virus adsorption to epoxy-fiber glass filters. This interfering effect was overcome by treating the leachate with an anion-exchange resin. Viruses in the resin-treated leachate were concentrated by adjusting the leachate to pH 3.5, adding AlCl
3
to a final 0.005 M concentration, adsorbing the viruses to an epoxy-fiber glass virus adsorbent, and eluting the adsorbed viruses in a small volume. When this method was used to concentrate poliovirus 100-fold in a variety of leachates, the average virus recovery efficiency was 37%. With the methods described in this study, it should be possible to efficiently monitor solid waste disposal site leachates for enteric viruses.
Effect of Potassium Sorbate on Salmonellae,
Staphylococcus aureus, Clostridium perfringens
, and
Clostridium botulinum
in Cooked, Uncured Sausage
Authors: Tompkin R. B. , Christiansen L. N. , Shaparis A. B. , Bolin H.
Published: December 2020

Skinless precooked, uncured sausage links with and without potassium sorbate (0.1% wt/wt) were inoculated with salmonellae,
Staphylococcus aureus, Clostridium perfringens
, and
Clostridium botulinum
and held at 27 C to represent temperature abuse of the product. Total counts of uninoculated product showed that the normal spoilage flora was delayed 1 day when sorbate was present. Growth of salmonellae was markedly retarded by sorbate. Growth of
S. aureus
was delayed 1 day in the presence of sorbate, after which growth occurred to the same level as in product without sorbate.
C. perfringens
declined to below detectable levels within the first day in product with and without sorbate. Sorbate retarded the growth of
C. botulinum
. Botulinal toxin was detected in 4 days in product without sorbate but not until after 10 days in product with sorbate.
Insensitivity of Homocitrate Synthase in Extracts of
Penicillium chyrosogenum
to Feedback Inhibition by Lysine
Authors: Masurekar Prakash S. , Demain Arnold L.
Published: December 2020

We previously reported that lysine inhibits in vivo homocitrate synthesis in the lysine bradytroph,
Penicillium chrysogenum
L
1
, and that such feedback inhibition could explain the known lysine inhibition of penicillin formation. In the present study, it was found that dialyzed cell-free extracts of mutant L
1
converted [1-
14
C]acetate to homocitrate. This homocitrate synthase activity was extremely labile but could be stabilized by high salt concentrations. The pH optimum of the reaction was 6.9, and the

K
m

was 5.5 mM with respect to α-ketoglutarate. The reaction was also dependent upon the presence of Mg
2+
, adenosine 5′-triphosphate, and coenzyme A. Surprisingly, the activity in these crude extracts was not inhibited by lysine. Benzylpenicillin at a high concentration (20 mM) partially inhibited the enzyme, an effect that was enhanced by lysine. Casein hydrolysate also partially inhibited the enzyme.
Hydrogen Sulfide-Producing Variants of
Escherichia coli
Authors: Maker Myron D. , Washington John A.
Published: December 2020

Seventeen strains of H
2
S-producing variants of
Escherichia coli
were isolated from specimens submitted for microbiological study (ten from stool, five from urine, and two from postmortem material). Production of H
2
S was unstable in several strains; however, other than their production of H
2
S, all strains closely resembled typical
E. coli
in their biochemical reactions. In vitro susceptibilities of the H
2
S-producing variants to antimicrobics closely resembled those of typical
E. coli
in this laboratory.
Recovery of
Escherichia coli
from Chlorinated Secondary Sewage
Authors: Braswell J. R. , Hoadley A. W.
Published: December 2020

Escherichia coli
ATCC 27622 injured during chlorination of secondary sewage failed to produce colonies on membrane filters incubated on m-FC medium or to grow and produce gas in lactose broth. Thus, standard methods for the enumeration of total and fecal coliforms in water and wastes should not be applied to chlorinated effluents.
Improved Isolation and Differentiation of Enterococci in Cheese
Authors: Efthymiou C. J. , Baccash P. , Labombardi V. J. , Epstein D. S.
Published: December 2020

Further documentation of an enterococcus selective differential (ESD) medium was obtained in isolations from eight different cheeses. An improved differentiation of tetrazolium salt (2, 3, 5-triphenyl tetrazolium hydrochloride [TTC])-reducing strains of
Streptococcus faecalis
from TTC-nonreducing or TTC-faintly-reducing
Streptococcus faecium
was attained. The sensitivity of the medium was evaluated in comparison with that of KF streptococcal, Pfizer selective enterococcus (PSE), the medium of Reinbold, Swern, and Hussong (RSH), and the medium of Saraswat, Clark, and Reinbold (SCR). Selective counts, rate of colony formation, and ease of isolation and differentiation of colonies were examined. The specificity of the medium was also investigated. ESD supported the fastest rate of growth and the maximum size of colonies; counts in this medium were in most cases possible with 17 h of incubation, whereas the other media required 24 to 48 h. A presumptive identification of 1,077 isolates by four biochemical tests disclosed that SCR, RSH, and ESD selected high, comparable percentages of strains that approximated most closely the typical description of enterococci (66, 60.1, and 58%, respectively). Low percentages (21.1 and 30.7%) were yielded by KF and PSE. The utility of ESD for a rapid, presumptive identification of enterococci was confirmed by serological and biochemical testing of color TTC-differentiated colonies isolated from 18 cheeses.
Studies on the Cecal Microflora of Commercial Broiler Chickens
Authors: Salanitro J. P. , Blake I. G. , Muirhead P. A.
Published: December 2020

A study was made of the cecal microflora isolated from broilers (5-week-old) reared under typical commercial husbandry conditions. Three hundred and twenty-five bacterial strains (randomly isolated from colonies representing 49 to 81% of the microscopic count) were isolated from cecal digesta of six animals on a rumen fluid roll tube medium (M98-5). Seventy-seven percent of these strains consisted of strict anaerobes: gram-negative, pleomorphic cocci (5.2%),
Peptostreptococcus
(1.5%), gram-positive rods (36.1% as
Propionibacterium acnes
and
Eubacterium
sp.), gram-negative rods (18.6% as
Bacteroides clostridiiformis, B. hypermegas
and
B. fragilis
) and sporeforming rods (15.7% as
Clostridium
sp.). Two types of facultatively anaerobic bacteria (gram-positive cocci and
Escherichia coli
) were also isolated and constituted 17.5% of the remaining flora. The distribution of the bacterial groups isolated from six cecal samples varied considerably. Data on the growth requirements of anaerobic strains indicated that many could be cultured in a simple medium consisting of an energy source, minerals, reducing agent, Trypticase, and yeast extract (or a vitamin mixture in place of yeast extract). The growth of some of these bacteria was also enhanced by CO
2
and rumen fluid. These preliminary data suggest that some of the more numerous anaerobes isolated from the chicken cecum may not require complex nutrients for growth and, in fact, may be nutritionally similar to rumen anaerobes.
Growth of Indigenous Organisms in Aerated Filtrate of Feedlot Waste
Authors: Weiner B. A. , Rhodes R. A.
Published: December 2020

Filtrates from feedlot waste were incubated under aerobic conditions to evaluate the availability of nutrients for cell production and to assess the capacity of indigenous flora to produce stabilized effluents. Incubation was carried out in 9-liter aerated jar fermentors. Three-fourths of the organic material and one-third of the nitrogen were taken up in 4 days; 90% utilization of organic material and nitrogen required almost a month. Acid was produced initially, but aerated liquid thereafter rapidly became alkaline. With pH controlled at 7.0, a comparable pattern of carbon utilization occurred, but nitrogen was incompletely used. The numerically dominant organisms in the waste inoculum were almost immediately displaced by an emergent population of a few types of organisms not originally evident. Maximal viable populations of 10
9
to 3 � 10
9
cells/ml were obtained in aerated waste liquid within 48 h; subsequently, numbers declined quickly to initial levels. Numbers of fungi, yeasts, and streptomycetes slowly increased but never exceeded their initial concentration by more than tenfold.
Ice Nucleation Induced by
Pseudomonas syringae
Authors: Maki Leroy R. , Galyan Elizabeth L. , Chang-Chien Mei-Mon , Caldwell Daniel R.
Published: December 2020

Broth cultures of suspensions of
Pseudomonas syringae
isolated from decaying alder leaves (
Alnus tenuifolia
) were found to freeze at very warm (-1.8 to -3.8 C) temperatures. The initiation of freezing appears associated with the intact cell and not with extracellular material. Chemical treatments and physical destruction of the cell destroy activity. Bacteria must be in concentrations of approximately 10
6
/ml before freezing at warm temperatures occurs.
Degradation of Oil Shale by Sulfur-Oxidizing Bacteria
Authors: Findley J. , Appleman M. D. , Yen T. F.
Published: December 2020

Approximately 40% of oil shale can be solubilized by the action of sulfur-oxidizing bacteria.
Thiobacillus thiooxidans
and
Thiobacillus concretivorous
are equally effective in solubilization. Continuous leaching experiments show that this process can be completed within 14 days. The growth of
Thiobacillus
and the production of acid were measured under several conditions. Almost all of the CaMg(CO
3
)
2
was removed by this process, leaving a complex of silica and kerogen that could be burned as low-energy fuel. The silica-kerogen complex had not yet been biologically degraded.
Comparison of Autoclave and Ethylene Oxide-Sterilized Membrane Filters Used in Water Quality Studies
Authors: Dutka B. J. , Jackson M. J. , Bell J. B.
Published: December 2020

Autoclave and ethylene oxide-sterilized membrane filters manufactured by Gelman, Millipore, and Sartorius were field tested for their recovery of total coliforms, fecal coliforms, fecal streptococci, and heterotrophs. The data were analyzed by using split-plot analysis of variance and significance tests. Membranes were also tested for pH and toxicity using
Escherichia coli
. The mean data summaries indicated that Gelman membrane filters generally produced the highest counts during the field studies. Statistical analyses of the March data showed that there were significant differences between membrane filters at 1% level; however, statistical analyses of June data revealed no significant differences except in total coliform recoveries. Toxicity tests at 35 C indicated that Gelman and Millipore autoclaved membrane filters were able to recover 92% of the test organisms. Toxicity tests performed at 44.5 C revealed that no membranes were able to recover more than 40% of the test organisms. Since differences were found in the ability of the three brands of membrane filters to recover bacteria from natural and controlled sources, membrane filters from different manufacturers cannot be readily interchanged. There is a need for a standardized procedure for testing bacterial recovery by membrane filters.
Origin and Structure of the Group-Specific, Complement-Fixing Antigen of
Rickettsia rickettsii
Authors: Tzianabos T. , Palmer E. L. , Obijeski J. F. , Martin M. L.
Published: December 2020

Rickettsia rickettsii
was treated with ether and examined by negative-contrast electron microscopy. Group-specific complement-fixing antigen was seen to be originating from the cell wall. The antigen was composed predominately of round particles 10 to 60 nm in diameter. Intact
R. rickettsii
and antigen from ether-treated organisms were purified by density gradient centrifugation and analyzed by polyacrylamide gel electrophoresis. The whole rickettsial cell was composed of a minimum of 30 proteins which ranged in molecular weight from about 23,000 to 155,000. The “soluble” antigen contained nine proteins ranging in molecular weight from about 28,000 to 150,000.
Simple Method for Preparation of Homogeneous Spore Suspensions Useful in Industrial Strain Selection
Authors: Queener S. W. , Capone J. J.
Published: December 2020

Homogeneous suspensions of streptomycete spores were desirable for plating after mutagenesis. Filtration through 8-μm membrane filters (Millipore Corp.) more effectively separated hyphae and spore clumps from single spores than did filtration through cotton wefts or paper.
Epoxy-Fiberglass Adsorbent for Concentrating Viruses from Large Volumes of Potable Water
Authors: Jakubowski Walter , Hoff John C. , Anthony Nathaniel C. , Hill William F.
Published: December 2020

A simple and compact virus-adsorbing unit for efficiently concentrating human enteric viruses from 100 gallons (about 380 liters) or more of potable water is described.
Quantitative Large-Volume Sampling Technique
Authors: Levin M. A. , Fischer J. R. , Cabelli V. J.
Published: December 2020

A filtration technique for high-volume sampling of water has been developed that, when combined with the most probable number procedure, permits the quantitation of microorganisms present at very low densities.
Non-Immunological Precipitation of Serum by Sodium Dodecyl Sulfate in Agar Diffusion
Authors: Cho C. T. , Feng K. K.
Published: December 2020

Marmoset serum or serum of other species of animal may react with sodium dodecyl sulfate and forms nonspecific precipitin lines in agar diffusion. The protein detergent complexes are not readily dialyzable. Therefore precipitin lines derived from studies that use sodium dodecyl sulfate-treated antigens in agar diffusion must be interpreted with caution.
Rapid Typing of Herpes Simplex Virus Strains Using the Indirect Immunoperoxidase Method
Authors: Benjamin Denis R.
Published: December 2020

The indirect immunoperoxidase technique with type-specific antisera was compared to kinetic neutralization for the typing of herpes simplex virus strains. There was complete agreement between the results obtained by kinetic neutralization and indirect immunoperoxidase. The indirect immunoperoxidase assay was far simpler to perform and interpret than the kinetic neutralization tests, and it offered a rapid means for the routine antigenic typing of herpes simplex isolates.
Rapid Method of Determining Cholera Vibrio Biotype
Authors: Mackowiak Philip A. , Huq Imbadul
Published: December 2020

The characteristic motility of cholera vibrios, as viewed through a dark-field microscope, and the adhesiveness of chicken cell-positive vibrios provide a means for rapidly identifying and biotyping cholera vibrios. Dilute suspensions of vibrios, such as one might find in a fresh rectal swab specimen from a cholera patient, when mixed with a 0.25% suspension of chicken erythrocytes in saline, can be used to biotype the cholera vibrios without prior isolation in pure culture. This is accomplished by using a dark-field microscope through which the chicken cell-positive cholera vibrios are observed to attach to the scattered erythrocytes and to propel them with a characteristic flipping motion.
Sensitive In Vivo Assay for Detection of Murine Leukemia Viruses
Authors: Peters Robert L. , Spahn Gerard J. , Rabstein Louise S. , Huebner Robert J. , Kelloff Gary J.
Published: December 2020

A test is reported for the in vivo detection of the replicative ability of murine leukemia viruses (MLV) in the BALB/c mouse strain. Growth in the spleen was assayed by the complement-fixation assay for MLV group-specific antigen after injection of newborn mice. Low doses of laboratory-derived and wild-type MLV from cell-culture and animal-grown sources were detected as early as 7 to 14 days postinoculation. The sensitivity of this in vivo test compared favorably with in vitro assays for MLV. In vivo detection of MLV replication was correlated with long-term oncogenicity.
Identification of
Salmonella
with the O-1 Bacteriophage
Authors: Welkos Susan , Schreiber Minnie , Baer Herman
Published: December 2020

The O-1 bacteriophage test of Cherry et al. (1954) for the presumptive identification of salmonellae in the diagnostic laboratory was investigated. A phage lysate with a titer of 10
12
plaque-forming units per ml was found to be optimal. This preparation lysed 98.2% of
Salmonella
strains tested, while maintaining its high specificity for salmonellae. Gram-negative organisms other than salmonellae were resistant to the O-1 phage; however, 5.9% of
Escherichia coli
strains tested were susceptible. The O-1 phage test is a simple, rapid, inexpensive, sensitive, and specific procedure for the identification of salmonellae in the diagnostic laboratory. A presumptive identification is obtained 1 day earlier than with conventional biochemical tests.
Staphylococcal Enterotoxin B and Nuclease Production Under Controlled Dissolved Oxygen Conditions
Authors: Carpenter David F. , Silverman Gerald J.
Published: December 2020

Enterotoxin B, nuclease, and total exoprotein production by
Staphylococcus aureus
strain S-6 was studied in a 0.5-liter fermentor system. While these extracellular products were elaborated over a wide range of aeration rates, maximal production occurred within the very narrow range of 125 to 150 cm
3
of air per min. The levels attained at the optimal aeration rate were not increased by maintaining a constant pH, although yield of enterotoxin:cell mass was highest at a constant pH of 7.0. During the growth cycle of the cultures, when aeration rate alone or aeration rate and pH were held constant, the dissolved oxygen (DO) levels, initially set at 100% of saturation, decreased to 5 to 10% 4 to 5 h after inoculation. The oxygen demand of the culture then maintained this level for an additional 4 to 6 h. This interval of low DO was characterized by maximal growth and exoprotein production. When the DO was controlled at a constant value throughout growth (by increasing or decreasing the airflow rate as appropriate), the culture demonstrated different optima for maximal growth and exoprotein production. A constant DO of 100% stimulated growth to extremely high densities, but the accumulation of toxin and nuclease was not observed. On the other hand, maintaining constant DO levels at 50 or 10% raised exoprotein levels higher than those achieved in a culture grown at the optimal aeration rate. Compared to the optimal aeration rate culture, the 10% DO culture yielded 20% more nuclease, 25% more toxin, and 40 to 50% more total exoprotein. These results indicate that it is the DO and not the aeration rate, per se, that is influential in controlling growth, toxin, nuclease, and total exoprotein production.
Value of the Concomitant Use of Complement Fixation and Immunodiffusion Tests in the Diagnosis of Coccidioidomycosis
Authors: Kaufman Leo , Clark Maxine J.
Published: December 2020

Complement fixation titers of 1:2 and 1:4 with coccidioidin are not always of diagnostic significance. The concurrent use of the complement fixation and immunodiffusion tests is an effective means for specific serologic diagnosis of coccidioidomycosis in patients with low levels of complement-fixing antibodies. In routine testing, it is recommended that only sera that are negative for complement-fixing antibodies at 1:8 but positive in the immunodiffusion test with coccidioidin be selected for titration at the 1:2 and 1:4 levels.
Comparison of Macroscopic, Microscopic, and Radiometric Examinations of Clinical Blood Cultures in Hypertonic Media
Authors: Rosner Richard
Published: December 2020

Clinical blood cultures were collected in the Bactec 8A flask (Johnston Laboratories, Cockeysville, Md.) and examined macrosopically, microscopically, and radiometrically in an effort to determine which approach produced the fastest detection time. Of 360 blood cultures found to contain organisms by subculture, 334 were first detected by Bactec, 98 by macroscopic examination, and 68 by microscopic examination. Examination times were at 4, 8, 16, 24, 36, and 48 h after collection of the specimen. Sixteen hours after specimen collection, microscopic examination had detected 31 positive cultures, macroscopic examination had detected two positive cultures, and Bactec had detected 160 positive cultures. By the end of the first 24 h of incubation, Bactec had detected 313 (93%) of those cultures eventually found to be positive. Although Bactec produced the fastest detection time in an overwhelming majority of the cultures, it failed to detect three of three
Candida
spp. cultures, three of five
Bacteroides
spp. cultures, and six of 32
Enterococcus
spp. cultures during the first 48 h of incubation.
Solid Phase Radioimmunoassay for Identification of
Herpesvirus hominis
Types 1 and 2 from Clinical Materials
Authors: Forghani Bagher , Schmidt Nathalie J. , Lennette Edwin H.
Published: December 2020

A solid phase radioimmunoassay (RIA) was developed for typing
Herpesvirus hominis
(HVH) strains isolated from clinical materials, and it also proved to be applicable to the direct detection and typing of HVH antigen in human and animal brain tissue. The procedure utilized virus-infected human fetal diploid cells or brain tissue smears in the bottom of 1-dram glass vials, antigen was detected through the use of intermediate HVH antisera produced in rabbits or hamsters and cross-absorbed with the HVH heterotype, and
125
I-labeled anti-species (rabbit or hamster) globulins produced in goats were used for detection of immune complexes. The cross-absorbed HVH antisera could be used at high dilutions in the RIA test, and they reacted with marked type-specificity in the RIA system. Specificity of the test was also improved by determining and using optimal concentrations of intermediate sera and of
125
I-labeled anti-species globulins. Results of typing HVH isolates by the RIA procedure agreed in all instances with those obtained by direct fluorescent antibody staining with cross-absorbed conjugates. The RIA procedure was effective and more sensitive than direct fluorescent antibody for demonstrating and typing HVH antigen directly in smears of infected human brain tissue.
Identification of Major High-Boiling Volatile Compounds Produced During Refrigerated Storage of Haddock Fillets
Authors: Chen T. C. , Nawar W. W. , Levin R. E.
Published: December 2020

The two major high-boiling volatile compounds produced during refrigerated storage of haddock fillets were found by gas chromatography and mass spectroscopy to be phenethyl alcohol and phenol.
Taxonomic Significance of Phenethyl Alcohol Production by
Achromobacter
Isolates from Fishery Sources
Authors: Chen T. C. , Levin R. E.
Published: December 2020

The formation of phenethyl alcohol from L-phenylalanine and ethanol by achromobacter isolates of fishery origin was found to be taxonomically significant for such organisms. Phenylpyruvate, the direct oxidative deamination product of L-phenylalanine, was found to serve as an intermediate precursor to phenethyl alcohol formation. Among ten
Acinetobacter
isolates examined, none produced phenethyl alcohol. Among nine
Moraxella
isolates examined, one produced phenethyl alcohol.
Concentration of Enteric Viruses from Water with Lettuce Extract
Authors: Konowalchuk J. , Speirs J. I. , Pontefract R. D. , Bergeron G.
Published: December 2020

A method for recovering enteroviruses, adenovirus, and reovirus from water with lettuce extract is described. Lettuce extract at pH 8.5 was added to the sample and the pH was reduced stepwise with hydrochloric acid to 4.0 to 4.5. The flocculent lettuce-extract particles, and adsorbed virus, were readily removed from solution by low-speed centrifugation. Electron microscopy suggests that, under conditions suitable for adsorption, virus particles are coated with the lettuce-extract colloid.
Incidence of
Clostridium botulinum
in Crabmeat from the Blue Crab
Authors: Kautter Donald A. , Lilly Timothy , LeBlanc Armand J. , Lynt Richard K.
Published: December 2020

The incidence of
Clostridium botulinum
in fresh crabmeat of blue crab was six out of 986 samples; in pasteurized crabmeat one sample out of 1,000 contained the organism.
Identification of
n
-Decane Oxidation Products in
Corynebacterium
Cultures by Combined Gas Chromatography-Mass Spectrometry
Authors: Bacchin Paolo , Robertiello Andrea , Viglia Aurelio
Published: December 2020

The gas chromatography-mass spectrometry technique was employed to characterize
n
-decane oxidation products of
Corynebacterium
strains 7E1C and 269 (SNAM Progetti collection) after 73 h of incubation at 35 C.
Corynebacterium
7E1C accumulated consistent amounts of esters of long chain acids with long chain alcohols, mainly decyldecanoate as well as products with mono- and diterminal carboxylic functions.
Corynebacterium
269 yielded 1-decanol and 1-10 decanediol as principal oxidation products.
Test Method for the Evaluation of Virucidal Efficacy of Three Common Liquid Surface Disinfectants on a Simulated Environmental Surface
Authors: Gaustad J. W. , McDuff C. R. , Hatcher H. J.
Published: December 2020

The Association of Official Analytical Chemists bacterial use-dilution test for evaluating liquid surface disinfectants was modified to determine the efficacy of three common environmental germicide compounds against representatives of four virus groups. Modifications were made to conform to the Environmental Protection Agency guidelines on virucidal testing procedures. Alterations included: the use of a concentrated tissue culture preparation of virus instead of a standard bacterial culture; HEp-2 tissue culture cells as a visible test system in place of standard nutrient broth; and controls to measure the virus titer end point and the toxicity of the disinfectant to the cell cultures. Comparison of control end points with results from the test proper were the measure of the effectiveness of the germicides against the viruses. Results are described which agree with those based on other methods previously reported.
Characterization of Lac
+
Transductants of
Streptococcus lactis
Authors: Molskness T. A. , Sandine W. E. , Brown L. R.
Published: December 2020

A phage-mediated transducing system was used in studying certain physiological characteristics of
S. lactis
C2 wild type, lactose-negative mutants, and lactose-positive transductants. Lac
-
mutants, obtained by acriflavine treatment of the wild type, were similar to the wild type in all characteristics tested except they lacked β-D-phosphogalactoside galactohydrolase (β-Pgal) and could not transport [
14
C]lactose; they also had approximately 10% of the proteolytic ability than wild-type cells. The lactose-fermenting characteristic was transduced from the wild type to Lac
-
mutants. The Lac
+
transductants obtained were similar to the wild-type parent with respect to lactose fermentation and level of β-Pgal activity (0.186 U of protein per mg). These transductants, however, had not regained full proteolytic ability and were similar to the Lac
-
mutant in this respect. Lactic acid production of the transductants in milk was approximately two-thirds that of the wild type. Data suggest that both the lactose-fermenting and proteolytic characters are carried on extrachromasomal particles (plasmids).
Differentiation of Staphylococcal and Micrococcal Proteinases by Electrophoresis
Authors: Scherer R. K. , Brown R. W.
Published: December 2020

The electrophoretic separation of the proteinases produced by staphylococci and micrococci was studied in four buffers. The duration of electrophoresis was based on the migration of a marker dye for a predetermined distance. The migration distances of the enzymes and dye were measured, and enzyme-dye values were calculated. A comparison of enzyme-dye values showed that complete separation of eight serologically different proteinases did not occur in any one buffer; however, in most instances, their relative order of migration was the same in all buffers. Certain strains of
Staphylococcus epidermidis
produced two proteinases that were different serologically as well as electrophoretically.
Staphylococcus aureus
strains, on the other hand, produced up to four proteinases that were serologically the same. The proteinases of staphylococci and micrococci can be best characterized by both electrophoretic and serological methods.
In-Use Contamination of Intravenous Infusion Fluid
Authors: Maki Dennis G. , Anderson Roger L. , Shulman Jonas A.
Published: December 2020

During the 1970 to 1971 nationwide epidemic of septicemias caused by
Enterobacter cloacae
and
Enterobacter agglomerans
traced to intrinsic contamination of Abbott intravenous infusion products, 94 infusion systems manufactured by Baxter Laboratories were studied microbiologically and epidemiologically during hospital use. Intravenous fluid from 10 systems (11%) contained microorganisms, usually
Staphylococcus
or
Bacillus
species; one infusion was heavily contaminated with
Klebsiella pneumoniae
. No national epidemic organisms,
E. cloacae
or
E. agglomerans
(formerly
Erwinia
), were recovered, suggesting that during this period frequent contamination with these organisms was unique to Abbott's infusion products. Contamination in this study appeared to be extrinsic in origin (introduced during clinical use) and related to the duration of continuous intravenous therapy. Nine of 61 systems (15%) that had been used longer than 48 h were contaminated, whereas only 1 of 33 used less than 48 h (3%) contained microorganisms. This study and the recent national outbreak indicate that contamination of infusion fluid, both from intrinsic and extrinsic sources, must be recognized as an additional risk of intravenous therapy; however, a once-daily replacement of the delivery apparatus can significantly diminish this hazard.
Effects of Seawater Cations and Temperature on Manganese Dioxide-Reductase Activity in a Marine
Bacillus
Authors: Ghiorse W. C. , Ehrlich H. L.
Published: December 2020

The seawater cations, Na
+
, K
+
, Mg
2+
, and Ca
2+
, each stimulated MnO
2
-reductase activity of whole cells and cell extracts of
Bacillus
29. Concentrations of Na
+
and K
+
which stimulated whole cells and cell extracts maximally were equivalent to those in two- to fivefold diluted seawater. Cell-extract activity was strongly stimulated by Ca
2+
and Mg
2+
up to a concentration of 0.01 M Mg
2+
and 0.002 M Ca
2+
, with little additional stimulation above these concentrations. Whole-cell activity was stimulated biphasically with increasing concentrations of Ca
2+
and Mg
2+
. Comparison of the effects of individual cations or mixtures of them at concentrations equivalent to their concentration in fivefold diluted seawater showed that more activity was obtained with 0.01 M Mg
2+
or 0.002 M Ca
2+
than with 0.1 M Na
+
, and more with 0.1 M Na
+
than with 0.0022 M K
+
. Fivefold diluted seawater permitted as much or more activity as solutions of individual or synthetic mixtures of the cations. Pre-exposure experiments showed that the ionic history of whole cells was important to their ultimate activity. The MnO
2
-reductase activity of induced whole cells exhibited a temperature optimum near 40 C. Cell extracts had different temperature optima (T
opt
), depending on whether induced glucose-linked activity (T
opt
= 25 C), uninduced glucose-linked, ferricyanide-dependent activity (T
opt
= 30 C), or uninduced ferrocyanide-linked activity (T
opt
= 40 C) were being measured. Some of these optima are higher than previously reported.
Recovery of Heated
Clostridium perfringens
Type A Spores on Selective Media
Authors: Barach J. T. , Adams D. M. , Speck M. L.
Published: December 2020

The enumeration of
Clostridium perfringens
spores on sulfite-polymyxin-sulfadiazine agar (SPS), tryptone-sulfite-neomycin agar (TSN), Shahidi-Ferguson-perfringens agar (SFP), tryptone-sulfite-cycloserine agar (TSC), and TSN lacking antibiotics (BASE) was studied. The spores were heated at 105 to 120 C by the capillary-tube method. The media were about equally efficient for the enumeration of heat-activated spores. Efficiency of the media for the recovery of spores surviving heat treatments at ultrahigh temperatures varied as follows: TSC ≥ SFP > BASE > SPS > TSN. Greater recovery when survivors were enumerated on TSC or SFP was attributed to germination of injured spores by the lysozyme present in the egg yolk emulsion used in these media. Low recovery of survivors on TSN and SPS was due to both the absence of lysozyme and inhibition of injured spores by the selective agents of these media. Recovery of heated spores was reduced greatly by polymyxin, neomycin, and kanamycin, and slightly by sulfadiazine and D-cycloserine. The addition of lysozyme to SPS or TSN did not improve the percentage of heat-injured spores recovered because the selective agents of these media interfered with the action of lysozyme. The suitability of the selective media for the enumeration of survivors was greatly affected by the presence of certain foods.
Diauxic Growth of
Propionibacterium shermanii
Authors: Lee Inn Hee , Fredrickson A. G. , Tsuchiya H. M.
Published: December 2020

Propionibacterium shermanii
has been anaerobically propagated in batch and continuous culture with glucose and/or lactate as energy source. Specific growth rate on lactate was observed to be the same as that on glucose. In terms of cell density, the yield on glucose is higher than the yield on lactate. But the molar ratio of yield on glucose to that on lactate, 8.35, is in good agreement with the theoretical value of 8. In a mixture of glucose and lactate,
P. shermanii
showed diauxic growth. It used lactate before glucose utilization began. Neither temporary growth cessation nor two distinct growth phases were observed. A mathematical model is proposed to describe the diauxic growth.
Simplified Extraction Procedure for Serological Grouping of Beta-Hemolytic Streptococci
Authors: Kholy Aziz El , Wannamaker Lewis W. , Krause Richard M.
Published: December 2020

An adaptation of the nitrous acid extraction of streptococci proved to be a reliable and practical method for the preparation of extracts for routine serological group identification. The extracts of all groups tested gave strong capillary precipitin reactions as well as reactions of double diffusion in gel. For routine grouping, extracts were prepared from the first one-half-plate subculture of the initial throat culture. The technique is simple and reliable, and it requires a minimum of technical skill, reagents, and equipment. Its use would facilitate epidemiological surveillance of group A streptococci and rapid diagnosis of streptococcal infections at a low cost.
Fermentation of Feedlot Waste Filtrate by Fungi and Streptomycetes
Authors: Weiner B. A. , Rhodes R. A.
Published: December 2020

The soluble and dispersed nitrogen and carbon components in the filtrate fraction of cattle feedlot waste are a potential nutrient source from which single-cell protein could be produced for animal feeds. The ability of more than 200 fungi and streptomycetes to grow in this liquid was determined; these included isolates from the waste and associated sources, as well as organisms maintained in the Culture Collection of the Agricultural Research Service in Peoria, Ill. Utilization of waste nutrients was measured by changes in nitrogen content and chemical oxygen demand. Only 20% of the organisms were able to grow appreciably in the filtrate. Of these, dry-weight yields varied from 0.6 to 2.7 g of mycelium per liter; from 21 to 50% of the nitrogen in the filtrates was used during growth, whereas chemical oxygen demand levels diminished from 4 to 60%. In general, streptomycetes isolated from the feedlot used nutrients from the filtrates better than fungi did. Addition of readily available carbon sources such as glucose or whey significantly increased (as much as sixfold) cell yields of selected organisms and promoted better utilization of nitrogen (from two- to threefold); the effect on chemical oxygen demand varied (0 to 33% increase).