bluuebunny/crossref_metadata_2025 huggingface dataset:
Monitoring of Low-Level Virus in Natural Waters
Authors: Sorber Charles A. , Sagik Bernard P. , Malina Joseph F.
Published: December 2020

The insoluble polyelectrolyte technique for concentrating virus is extended to extremely low virus levels. The effectiveness of this method employing a coliphage T2 model is a constant 20% over a range of virus levels from 10
3
to 10
−4
plaque-forming units/ml. The efficiency of the method is dependent upon
p
H control during the concentration phase. Although the study was initiated to develop a method for quantitating the effectiveness of water and wastewater treatment methods for the removal of viruses from waters at low concentrations, the potential of the technique for efficient monitoring of natural waters is apparent.
Hemagglutination Inhibition with Arboviruses: Relationship Between Titers and Source of Erythrocytes
Authors: Mettler Norma E. , Clarke Delphine H. , Casals Jordi
Published: December 2020

Antigens for Grand Arbaud, Hazara, and California arboviruses were able to agglutinate goose and either dog, hamster and guinea pig, or hamster red blood cells (RBC) to the same titer at the same
p
H; in hemagglutination-inhibition (HI) tests, titers for homologous and related sera were the same with these different types of RBC or occasionally one dilution higher with the mammalian cells. Antigens for St. Louis encephalitis and Eastern equine encephalitis viruses required use of lower antigen dilutions with human, guinea pig, and hamster RBC than with goose RBC. The results of comparative HI testing with these latter antigens and types of RBC indicate that HI titer is not directly related to the antigen dilution used with different types of RBC.
Quantitative Nasal Culture: a Tool in Antibiotic Research
Authors: Martin R. Russell , White Arthur
Published: December 2020

The use of the quantitative nasal culture was investigated as a means of evaluation of new antimicrobial drugs in man. Cyclacillin was somewhat more active in vitro than penicillin G against penicillin G-resistant organisms. Cyclacillin was highly effective in suppressing staphylococci susceptible to penicillin G in nasal carriers but did not suppress staphylococci resistant to penicillin G. Although in previous studies by others cyclacillin was effective in treating mice infected with penicillin G-resistant staphylococci, in the present studies cyclacillin was not effective in suppressing nasal penicillin G-resistant staphylococci in man at doses which markedly suppressed penicillin G-sensitive organisms.
Reduction of Nucleic Acid Content in
Candida
Yeast Cells by Bovine Pancreatic Ribonuclease A Treatment
Authors: Castro A. C. , Sinskey A. J. , Tannenbaum S. R.
Published: December 2020

Yeast as a source of protein for human consumption is limited by its relatively high nucleic acid content. In this study, we developed an enzymatic method of decreasing the nucleic acid content.
Candida utilis
cells, heat-shocked at 80 C for 30 sec, were treated with bovine pancreatic ribonuclease A. Maximum leakage of nucleic acid was observed when the incubation temperature was between 55 and 65 C, the
p
H of the system from 6.75 to 8.0, and the enzyme-to-cell ratio 1:10,000 on a weight-by-weight basis. Other factors, such as yeast strain, age of cells, and method of propagation, did not influence the susceptibility of the yeast cells to the action of ribonuclease. Buffers and monovalent cations had no inhibiting effects. Magnesium and calcium ions at concentrations greater than 0.001
m
showed marked inhibition on the rate of nucleic acid leakage. This enzymatic method reduced the nucleic acid content of yeast cells from 7.5 to 9.0% to 1.5 to 2.0% with no significant concomitant loss of protein.
Antifungal Activity of Substituted Nitrobenzenes and Anilines
Authors: Gershon Herman , McNeil Maynard W. , Parmegiani Raulo , Godfrey Patricia K.
Published: December 2020

Series of 1,3-dihalogeno-5-nitrobenzenes, 3- and 3,5-halogenoanilines, and 2,6-dihalogeno-4-nitroanilines were tested for fungitoxicity against
Aspergillus niger, A. oryzae, Trichoderma viride, Myrothecium verrucaria
, and
Trichophyton mentagrophytes
in shaken culture by using Sabouraud dextrose broth enriched with yeast extract as the test medium. 1,3-Dichloro-5-nitrobenzene, 1,3-dibromo-5-nitrobenzene, 3-iodoaniline, 3,5-dichloroaniline, and 3,5-dibromoaniline were found to possess sufficient activity, compared with 8-quinolinol, to warrant further study.
Transport Media for Herpes Simplex Virus Types 1 and 2
Authors: Nahmias A. , Wickliffe C. , Pipkin J. , Leibovitz A. , Hutton R.
Published: December 2020

An evaluation was made of the recovery rate of herpes simplex virus (HSV) type 1 or 2 from 197 clinical specimens obtained in two or three charcoal transport media: Leibovitz viral transport medium, a modified Leibovitz-Emory medium (LEM), in which agarose was used instead of agar, and Amies bacterial transport medium. The specimens were stored and shipped for 1 to 19 days in these media at ambient temperature or in Hanks buffered-salt solution in dry ice. The results indicate that the LEM was most effective, particularly in the recovery of HSV type 2 from clinical specimens held at ambient temperature. In vitro and in vivo studies in genitally infected mice corroborated the observations obtained with human clinical specimens. The availability of transport media which can be used for shipment at ambient temperature offers clinicians easier accessibility to laboratory confirmation and antigenic typing of HSV from suspect herpetic infections.
Antibacterial Activity of Ronidazole
Authors: Miller A. Kathrine
Published: December 2020

Ronidazole, a nitroimidazole that has in vivo antiparasitic and antimycoplasmal activity, also has some in vivo antibacterial activity.
Production of
d
-Mannitol by Conidia of
Aspergillus candidus
Authors: Nelson G. E. N. , Johnson D. E. , Ciegler A.
Published: December 2020

Conidia of
Aspergillus candidus
converted glucose and other sugars to mannitol. Low
p
H (ca. 3.0) apparently favored the percentage yield but decreased the fermentation rate.
Solubilization of Iron-Containing Minerals by Soil Microorganisms
Authors: Arrieta Luis , Grez Renato
Published: December 2020

Eighty-eight strains of microorganisms were isolated from soils collected in northern and southern Chile, and 10 fungi which showed the highest solubilizing action upon the iron in granodiorite were then selected. These fungi were incubated with the following iron-containing minerals: augite, hornblende, biotite, magnetite, hematite, and the igneous rock granodiorite. The solubility of iron in these minerals depended on their nature, crystalline structure, the concentration of metabolic products, or all three. Complex formation could be the mechanism involved, as a strong cation-exchange resin was not able to extract Fe from culture solutions. This conclusion is also confirmed by the R
F
values obtained by thin-layer chromatography of iron-containing culture solutions.
Effect of Controlled Atmosphere on Growth of Mold on Synthetic Media and Fruit
Authors: Yackel Walter C. , Nelson A. I. , Wei L. S. , Steinberg M. P.
Published: December 2020

Growth of seven spoilage molds on agar plates at several temperatures in both controlled atmosphere (CA) and in air was studied. Each mold responded somewhat differently to CA at each temperature; however, there were some general tendencies. The lag phase was generally increased by CA and, in some cases, was substantially extended when incubation was just above the minimum growth temperature. The mycelial structure of molds seems to be different when grown in CA than when grown in air. With only two exceptions of 24 holding conditions, the maximum amount of mycelia was always less in CA than in air. Spore development varied with each mold at each temperature; generally, it was considerably less in CA than in air. CA storage of cherries above 34 F (1 C) did not retard mold infection to any extent; at 34 F, mold growth was inhibited and storage life was extended several days as compared to air storage. CA storage of strawberries at 34 F resulted in a mold-free product after 7 days of incubation, whereas the air-stored berries were slightly infected. However, when mishandled berries showing some mold growth were stored at 34 F, CA did not stop further mold growth.
Anaerobic Roll Tube Media for Nonselective Enumeration and Isolation of Bacteria in Human Feces
Authors: Eller Charles , Crabill Melvin R. , Bryant Marvin P.
Published: December 2020

Medium 10 (M10), developed for rumen bacteria and containing small amounts of sugars, starch, volatile fatty acids, hemin, Trypticase, yeast extract, cysteine, and sulfide, plus agar, minerals and CO
2
-HCO
3
-buffer, was used with the Hungate anaerobic method as a basal medium to evaluate the efficacy of various ingredients. Three-day-old colony counts from adults on normal diets (17 samples) were 0.55 × 10
11
to 1.7 × 10
11
per g (mean, 1.15 × 10
11
) for M10. Single deletion of volatile fatty acids, Trypticase, yeast extract, or sulfide did not reduce counts. Deletion of hemin or both Trypticase and yeast extract significantly lowered counts. Addition of fecal extract, rumen fluid, 1% dehydrated Brain Heart Infusion (BHI) or 2 to 6% liver infusion did not increase counts; 1% dehydrated bile or 3.7% BHI markedly depressed them. Decreasing the gas-phase CO
2
concentration from 100 to 5% with N
2
and correspondingly lowering the HCO
3
had little effect. Counts in supplemented Brewer Thioglycollate (Difco), BHI, and Trypticase soy agar were similar or lower than in M10; ease in counting was best in M10. Comparison of features of 88 predominant strains of fecal bacteria randomly isolated indicated that M10 supported growth of as many or more species of bacteria as compared to supplemented BHI. The results suggest that predominant bacteria of human feces, in general, are not as nutritionally fastidious as rumen bacteria and indicate that media for counts or isolation containing large amounts of rich organic materials are neither necessary nor desirable when adequate anaerobic techniques are used.
Serological Typing of 31 Achromogenic and 40 Melanogenic
Pseudomonas aeruginosa
Strains
Authors: Yabuuchi Eiko , Miyajima Noriko , Hotta Hisako , Furu Youichi
Published: December 2020

Thirty-one achromogenic and 40 melanogenic
Pseudomonas aeruginosa
strains were studied with 10 monovalent typing sera (3). Twenty-one of the achromogenic (67.7%) and seven of the melanogenic (17.5%) strains were agglutinated by one of the 10 typing sera. Ten achromogenic and 33 melanogenic strains were not agglutinated by any of the 10 typing sera. As far as this set of antisera is concerned, the typability of achromogenic and melanogenic
P. aeruginosa
strains appears to be much lower than that of the chromogenic, nonmelanogenic strains of the species reported previously.
Improvements in the Growth of BHK-21 Cells in Submerged Culture
Authors: Radlett P. J. , Telling R. C. , Stone C. J. , Whiteside J. P.
Published: December 2020

A medium is described which will support the submerged culture of BHK-21 cells to 6.5 × 10
6
to 7 × 10
6
cells/ml in volumes up to 30 liters. Shaken-flask cultures were used to determine nutrient deficiencies in depleted medium. The final medium became limited by glutamine at 6.5 × 10
6
to 7 × 10
6
cells/ml, but increasing the glutamine concentration failed to improve cell yields. The value of the polyol Pluronic F68 as a protective substance is illustrated.
Thermal Inactivation of Aerosolized
Bacillus subtilis
var.
niger
Spores
Authors: Mullican Charles L. , Buchanan Lee M. , Hoffman Robert K.
Published: December 2020

A hot-air sterilizer capable of exposing airborne microorganisms to elevated temperatures with an almost instantaneous heating time was developed and evaluated. With this apparatus, aerosolized
Bacillus subtilis
var.
niger
spores were killed in about 0.02 sec when exposed to temperatures above 260 C. This is about 500 times faster than killing times reported by others. Extrapolation and comparison of data on the time and temperature required to klll
B. subtilis
var.
niger
spores on surfaces show that approximately the same killing time is required as is necessary for spores in air, if corrections are made for the heating time of the surface.
Comparison by Gas-Liquid Chromatography of the Fatty Acids of
Mycobacterium avium
and Some Other Nonphotochromogenic Mycobacteria
Authors: Thoen Charles O. , Karlson Alfred G. , Ellefson Ralph D.
Published: December 2020

Fifty-eight strains of nonphotochromogenic mycobacteria representing nine different serotypes were studied, including 38 strains of
Mycobacterium avium
and 20 strains of Battey bacilli. The lipids were extracted from whole cells, saponified with potassium hydroxide, and esterified with diazomethane. The fatty-acid profiles determined by gas-liquid chromatography included saturated fatty acids ranging from C
8
to C
24
, plus some unsaturated analogues and a branched-chain acid. No consistent differences in the fatty-acid profiles were observed between strains of
M. avium
and Battey bacilli. Quantitative differences in the means (significant at
P
< 0.01) were observed in the relative amounts of 14:0, 16:1, 18:0, 18:1, and a branched-chain acid among strains of the same serotype. We were unable to differentiate the fatty-acid profiles of recently isolated strains or those maintained in culture for more than 2 years.
Resistance of
Bacillus subtilis
Spores to Inactivation by Gamma Irradiation and Heating in the Presence of a Bactericide
Authors: Deasy P. B. , Küster E. , Timoney R. F.
Published: December 2020

Aqueous suspensions of
Bacillus subtilis
NCTC 8236 spores, surviving gamma irradiation from a cesium-137 source, exhibited an enhanced rate of inactivation compared to nonirradiated spores when heated with 0.04% phenylmercuric nitrate. The enhanced rate of inactivation, observable from survival curves, was noted when spores were irradiated with 150,000 rad under air in either the presence or absence of the bactericide. The magnitude of the enhanced inactivation rate increased as the irradiation dose under air increased from 150,000 to 300,000 rad. The inactivation rates of spores surviving irradiation with 150,000 rad under either oxic or anoxic conditions did not exhibit a simple quantitative relationship. The enhancement effect was observed when the severity of the heat treatment was increased by either reducing the
p
H from 8 to 6 or raising the temperature from 70 to 90 C.
Transmission of
Salmonella montevideo
in Wheat by Stored-Product Insects
Authors: Crumrine Martin H. , Foltz Vernon D. , Harris John O.
Published: December 2020

Sitophilus oryzae
(L.),
S. granarius
(L.),
Tribolium castaneum
(Hbst.),
Oryzaephilus surinamensis
(L.),
Rhyzopertha dominica
(F.),
Tenebroides mauritanicus
(L.), and
Cryptolestes pusillus
(Schon.) transmitted
Salmonella montevideo
from wheat contaminated with 10
6
organisms/g to clean wheat. The insects were fed on the contaminated grain for 21 days and were then transferred to clean grain and allowed to feed for 21 days. They were subsequently transferred to two more samples of clean wheat. All species carried
S. montevideo
into the initial sample of clean wheat but not into a second or third sample. Progeny of the original insects that developed in the contaminated wheat exhibited less ability than the original adults to contaminate clean wheat. Data indicated that few
S. montevideo
could be carried by the stored-product insects in large masses of grain.
Modified Selective and Differential Isolation Medium for
Vibrio parahaemolyticus
Authors: Twedt Robert M. , Novelli Rose Mary E.
Published: December 2020

The semiselective salt-starch-agar formulation of Baross and Liston was modified as the result of a systematic study of the effect of each constituent on the growth of
Vibrio parahaemolyticus
and competitive species characteristic of the marine environment. The selection of nutrient constituents depended on an analysis of their effect on generation time. The addition of inhibitors depended on an analysis of minimal inhibitory concentrations. The modified formulation included: peptone, 2.0%; yeast extract, 0.2%; corn starch, 0.5%; NaCl, 3.0%; agar, 1.5% (
p
H 8.0). Penicillin at 2 to 5 units/ml increased selectivity without significantly inhibiting
Vibrio
in pure suspensions. Over 62% of the most sensitive strain (YM-K33) was recovered at a concentration of 5 units of penicillin per ml. The per cent recovery of
V. parahaemolyticus
from fish homogenate compared favorably with other selective formulations. At an initial concentration of 10
5
cells/ml, recovery varied with the strain used from 60 to 119%, whereas at 10
2
cells/ml the range was 36 to 94%. Applications of the medium for
Vibrio
quantification are discussed.
Sensitive Procedure for Detecting Residual Viable Virus in Inactivated Rabies Vaccine
Authors: Mitchell J. R. , Everest R. E. , Anderson G. R.
Published: December 2020

A procedure for testing inactivated rabies vaccines of tissue culture origin for residual viable virus is reported in which the vaccine to be tested is passed in primary hamster kidney cell culture (
PHK
) before mouse inoculation. In preliminary experiments, titrations of rabies virus in which each dilution was passed in
PHK
before inoculating mice yielded titers 100 to 10,000 times higher than the titers obtained for the same virus by direct mouse inoculation. This rabies virus amplification procedure was evaluated by testing 18 lots of inactivated rabies vaccine of tissue culture origin. No viable virus was found in these vaccine lots when tested by direct intracerebral inoculation of mice. Eight of these 18 lots were found to contain viable virus, however, when tested by passage in
PHK
cell culture. The significance of low levels of viable virus in rabies vaccines is discussed. It is recommended that the amplification procedure described in this report be used in the safety testing of rabies vaccines of tissue culture origin and that it be evaluated for use in testing other rabies vaccines of low tissue content.
Immunodiffusion Analysis of Isolates of
Xanthomonas cyamopsidis
Authors: Orellana R. G. , Weber D. F.
Published: December 2020

Immunodiffusion analysis of intact, sonically treated, and sonically treated and heat-treated cell antigen preparations of isolates of races 0 and 1 of
Xanthomonas cyamopsidis
of guar,
Cyamopsis tetragonoloba
, indicated that these races differ from one another antigenically. The differentiating precipitin reactions are believed to have been brought about by specific heat-stable surface antigens, possibly similar to lipopolysaccaride somatic antigens of other slime-producing xanthomonads. Because differences in host reaction to inoculation with the two isolates of race 1 were known to be minor, these isolates are considered to represent serotypes of the race rather than distinct separate races. This conclusion is supported by the antigenic behavior of isolates 14 and 19 to antiserum 19. The applicability of immunodiffusion analysis for the study of pathogenic variability in
X. cyamopsidis
is demonstrated.
Substitution of Milk for Serum in the Production of Human Leukocyte Interferon
Authors: Cantell K. , Tovell Dorothy R.
Published: December 2020

The presence of serum in suspensions of Sendai-induced human leukocytes is necessary for the synthesis of significant amounts of interferon. Very little interferon is obtained from serum-free suspensions. Cow's milk or milk casein can substitute for serum in the production of high yields of human leukocyte interferon.
Influence of Fungicides and Irrigation Practice on Aflatoxin in Peanuts Before Digging
Authors: Pettit Robert E. , Taber Ruth Ann , Schroeder Harry W. , Harrison Arthur L.
Published: December 2020

Peanuts grown under dryland conditions where drought stress occurred accumulated more aflatoxin before digging than peanuts grown under irrigation. Kernels became more susceptible to
Aspergillus flavus
and
A. parasiticus
invasion when the soil moisture in the pod zone approached levels at which moisture moved from the pod into the soil and the kernel moisture dropped below 31%. Isolation frequencies of these aspergilli from fresh-dug kernels were lowest in 1968 (maximum of 3%). In 1967 and 1969, maximum percentages of 100 and 74, respectively, were noted. Kernel infestation was correlated with degree of aflatoxin contamination. Dryland fresh-dug kernels contained a maximum of 35,800 parts per billion aflatoxin while a maximum of 50 parts per billion was detected in kernels from irrigated plots. In 1969
A. flavus
infestation was as high as 59% in peanuts from irrigated plots; however, no aflatoxin was detected. Absence of aflatoxin in these samples is attributed to the higher kernel moisture content which reduced the aflatoxin-producing potential of
A. flavus.
Statistical analysis of the data revealed no significant differences in degree of fungal infestation, production levels, and grade factors between any fungicide treatments.
Disc Plate Method of Microbiological Antibiotic Assay
Authors: Davis W. W. , Stout T. R.
Published: December 2020

A detailed disc plate procedure is introduced for assay of antibiotics. The procedure is based on a previous study by the authors and deviates from conventional procedures in several respects: selected plastic petri dishes are employed; critical temperature control is simply provided at all stages of the test with refrigeration of the plates never used; all dilution is done with displacement microburettes; six pads (6.3 mm diameter) per dish are employed, all filled with the same unknown or reference solution; the sequence of all plates handled on 1 day is made a part of the protocol which allows accounting for the influence of the order of pouring and setting the plates; external reference plates are set at specified locations in the sequence; and, by averaging the diameters of all zones on a plate, most of the consequence of wedge shape of agar in plates, which is common and almost unavoidable, is removed. The present method is economical, uses simple facilities, and provides good accuracy of test results.
Bacillus subtilis
was most commonly employed, but other organisms may be employed in the present procedure.
Effect of Relative Humidity on Survival of
Candida albicans
and Other Yeasts
Authors: Mackenzie D. W.
Published: December 2020

Individual blastospores of
Candida albicans
were deposited on the surface of 50-mm membranes (Millipore Corp.) and placed within sealed glass chambers at various relative humidities (RH). After 48 hr, virtually all cells maintained at 100 and 10% RH had survived, but 84% of the cells maintained at 60% RH failed to develop into colonies when transferred to Sabouraud medium. No morphological abnormalities could be observed in cells surviving low RH values, but their initial rate of multiplication after transfer to Sabouraud medium was greatly reduced, compared to that demonstrated by cells maintained at 100% RH. At 60% RH, the exposure time required to kill 50% of the blastospores was 2 to 3.5 days. The inimical effect of 60% RH was confirmed in a total of 21 isolates of
C. albicans.
No deleterious effect was noted when 12 other species of yeasts were subjected to 10, 60, and 100% RH. The single isolate of
Candida brumptii
and 1 out of the 20 isolates of
Cryptococcus neoformans
tested also failed to grow after blastospores had been exposed to 60% RH for 4 days.
Isolation and Counting of
Athiorhodaceae
with Membrane Filters
Authors: Swoager W. C. , Lindstrom E. S.
Published: December 2020

The number, type, and distribution of
Athiorhodaceae
in two Central Pennsylvania artificial lakes were investigated with an anaerobic modification of the membrane filter technique.
Staphylococcus epidermidis
BV: Antibiotic Resistance Patterns, Physiological Characteristics, and Bacteriophage Susceptibility
Authors: Schaefler S.
Published: December 2020

Staphylococcus epidermidis
BV is a group of mannitol-fermenting coagulase-negative staphylococci characterized by multiple antibiotic resistance, very similar biochemical characteristics, and phage susceptibility. Clinical isolates belonging to this group are resistant to most antibiotics tested, including oxacillin, lincomycin, and novobiocin. The only antibiotic to which all tested strains are sensitive is vancomycin. Common biochemical traits of the tested
S. epidermidis
BV strains include fermentation of trehalose and ribose, phospho-β-glucosidase activity, growth on synthetic medium with amino acids as carbon source, and lack of deoxyribonuclease, phosphatase, lipase, and gelatinase activity. Some of these characteristics appear more frequently in mannitol-positive control strains than in mannitol-negative strains.
S. epidermidis
BV strains carry lysogenic phages with a host range restricted to this group. These phages allow the differentiation of individual strains.
Viable, Avirulent
Leptospira interrogans
Serotype
pomona
Vaccine: Preservation in Liquid Nitrogen
Authors: Stalheim O. H. V.
Published: December 2020

By the addition of glycerol (10%, v/v), viability titers of serotype
pomona
vaccine were maintained within 1 to 2 logs (base 10) during controlled-rate freezing and storage in liquid nitrogen.
Defined Liquid Minimal Medium for
Caryophanon latum
Authors: Kele Roger A. , McCoy Elizabeth
Published: December 2020

A defined medium has been developed for the trichome-forming bacterium,
Caryophanon latum.
Acetate is the main carbon and energy source, and either
N
-glutamate, or
N
-NH
4
can be used as the nitrogen source.
Isolation of Echoviruses with Human Embryonic Lung Fibroblast Cells
Authors: Hatch Milford H. , Marchetti George E.
Published: December 2020

More echovirus isolants were obtained from clinical specimens with a strain of human embryonic lung fibroblast cells (RU-1) than with primary rhesus monkey kidney cells.
Chemically Defined Medium for the Growth of
Clostridium perfringens
Authors: Riha William E. , Solberg Myron
Published: December 2020

A defined medium which supports growth of
Clostridium perfringens
at low inoculum levels was developed. Generation time for strain 8797 was 1.5 times greater than previously reported for growth in purged fluid thioglycolate medium.
Improved Method for Virus Structural Polypeptide Analysis on Dissociating Acylamide Gel
Authors: Boulanger P. A. , Warocquier R.
Published: December 2020

A method is described in which polypeptides can be separated, with a high band resolution, by electrophoresis through “pore gradient” acrylamide gel (15 cm in length) in a sodium dodecyl sulfate-urea dissociating system. The applicability of this technique to the analysis of virus structural components was examined with the adenovirus type 2 model system.
Estimation of the Growth of the T
1
Strain of
Mycoplasma mycoides
in Tryptose Broth by the Measurement of Lactate Dehydrogenase
Authors: Read W. C. S. , Boarer C. D. H. , Read J. Julie
Published: December 2020

The measurement of lactate dehydrogenase activity has been used to evaluate the growth of the T
1
vaccine strain of
Mycoplasma mycoides
var.
mycoides
in broth during the production of vaccine. Estimations were made during incubation at 37 C and storage at 4 C. The results were compared with titers of the vaccine obtained by two conventional methods of assessing viability titers: the counting of colonies formed on solid medium and a 50% end point titer found after dilutions were made in broth. The method of measuring lactate dehydrogenase activity allowed the rapid enumeration of organisms during incubation of the culture, but estimations made on vaccine stored at 4 C did not compare well with the two conventional methods of assessing viability. The lactate dehydrogenase activity of the culture has enabled rapid monitoring of the production stages of this vaccine.
Use of Disposable Micro Tissue Culture Plates for Antiviral and Interferon Induction Studies
Authors: Sidwell Robert W. , Huffman John H.
Published: December 2020

A reproducible test system requiring small amounts of test compound was developed for evaluating antiviral and interferon-inducing activity. In the antiviral experiments, KB cells were grown in disposable polystyrene microplates covered with a standard domestic plastic wrap. Viruses used in the system were types 1 and 2 herpes simplex virus, vaccinia virus, type 3 adenovirus, myxoma virus, pseudorabies virus, type 3 parainfluenza virus, types 1A and 13 rhinovirus, vesicular stomatitis virus, coxsackievirus B, and type 2 poliovirus. Inhibition of viral cytopathogenic effect was the primary criterion of evaluation of antiviral activity. Reduction in cell and supernatant fluid virus titers was used as a secondary means of evaluation. The microplate system was adaptable for determining prophylactic, therapeutic, and inactivating effects against viruses. Mouse L-929 cells were used for the interferon induction studies, with vesicular stomatitis virus utilized as the indicator of interferon activity. Known active compounds evaluated in this microplate system had activity similar to that seen in macro in vitro systems.
Isolation and Identification of Adenoviruses in Microplates
Authors: Sullivan Elizabeth J. , Rosenbaum Max J.
Published: December 2020

A procedure for isolating and identifying adenoviruses in microplates is described. Comparison tests with standard tube methods show an agreement of 92%. Virus isolations are greatly facilitated by the microplate method. This method is sensitive, economical, and especially applicable to large-scale epidemiological surveys.
Reversal of the Antimicrobial Activity of Trimethoprim by Thymidine in Commercially Prepared Media
Authors: Koch Audrey E. , Burchall James J.
Published: December 2020

The ability of a potent dihydrofolate reductase inhibitor, trimethoprim, to inhibit the growth of
Escherichia coli
B in vitro is dependent on the composition of the medium in which the cells are grown. The inhibition observed in minimal broth could be partially reversed by the addition of thymidine, ribonucleosides, amino acids, and vitamins. No reversal occurred in the absence of thymidine. In a number of commercially prepared media, the inhibitory activity of trimethoprim correlated inversely with the amount of thymidine found to be present by microbiological assay. The significance of these findings for the routine testing of new, synthetic antibacterial agents is discussed.
Antimicrobial Susceptibility as a Diagnostic Aid in the Identification of Nonfermenting Gram-Negative Bacteria
Authors: Gilardi G. L.
Published: December 2020

Antimicrobial susceptibility data regarding nonfermentative, gram-negative bacteria (
Pseudomonas, Alcaligenes, Acinetobacter, Moraxella, Flavobacterium
) are presented showing that the antibiograms of most species examined can be used as an important auxillary aid in their differentiation.
Staphylococcal Enterotoxin B: Solid-Phase Radioimmunoassay
Authors: Johnson Howard M. , Bukovic Joann A. , Kauffman Peter E. , Peeler J. T.
Published: December 2020

An immunoassay employing
125
I-labeled enterotoxin B and polystyrene tubes coated with specific antibody was used for assaying purified and crude enterotoxin. Antibody was adsorbed to untreated polystyrene tubes. Unlabeled enterotoxin competed with
125
I-labeled enterotoxin for antibody-combining sites. The uptake of
125
I-labeled toxin reflected the concentration of unlabeled toxin present. The test is sensitive to 1 to 5 ng of purified and crude enterotoxin B per ml, and cross-reactions with heterologous enterotoxins did not interfere with the specificity. This test possesses the combination of sensitivity and objectivity absent in current methods for assaying enterotoxin and provides a model for investigating other enterotoxin serotypes.
Inactivated Eastern Equine Encephalomyelitis Vaccine Propagated in Rolling-Bottle Cultures of Chick Embryo Cells
Authors: Cole Francis E.
Published: December 2020

A method was developed for the production of Eastern equine encephalomyelitis vaccine from virus grown in rolling-bottle cultures (840 cm
2
growth area) of chick embryo cells. The PE-6 strain of virus was propagated in chick embryo cell roller cultures maintained on serum-free medium 199 containing 0.25% human serum albumin and antibiotics (MM). A multiplicity of inoculum of 0.005 yielded acceptable titers of virus at a convenient harvest time of 18 to 24 hr and reduced the carry-over of extraneous material from the virus seed. Growth studies in which 100, 200, or 300 ml of MM was used showed that use of 300 ml of MM offered two advantages: (i) cytopathic effects were less at the 18- to 24-hr harvest time, thereby decreasing cellular material in the final product, and (ii) total virus yield was not substantially reduced, thus permitting large-scale production of virus for further processing. Studies on formalin inactivation at 37 C indicated that the virus was inactivated by 0.05% formalin within 12 to 16 hr and with 0.1% formalin within 6 to 8 hr. Antigen extinction tests in hamsters revealed excellent potency (e.g., median-effective-dose values of 0.069 to 0.012 ml) for both fluid and freeze-dried products. The advantages of the roller-bottle technique in vaccine production are discussed.
Automated Radiometric Detection of Bacteria in 2,967 Blood Cultures
Authors: DeBlanc Harold J. , DeLand Frank , Wagner Henry N.
Published: December 2020

A new radiometric method for the automatic detection of bacterial growth in blood cultures has been compared with conventional methods. A total of 2,967 cultures from 1,280 patients suspected of having bacteremia were studied. A 2-ml amount of blood was inoculated into culture media in which the glucose was labeled with carbon-14. The release of
14
CO
2
by bacterial metabolism was checked hourly for 18 to 24 hr, daily for the next 2 days, and, on the 12th day, with an automated instrument. A 10-ml amount of blood was studied by conventional bacteriological techniques. In 125 cultures from 50 patients, there was bacterial growth in at least one of the routine media. Of these, the radiometric method detected 102 cultures from 40 patients. In 111 cultures from 48 patients, there was radiometric detection of bacterial growth. In all of these cultures, there was detection of bacterial growth in subcultures from the radioactive medium. Of these, the routine laboratory detected 98 cultures from 40 patients. Neither method detected all patients with bacteremia. Among the 57 patients positive by one or both methods, routine techniques detected bacteria in 87% and the radiometric method detected bacteria in 85%. Seventy per cent of the cultures were detected first by the radiometric method, 65% on the day of inoculation. Our results suggest that the radiometric method is faster than conventional techniques and comparable in accuracy. Its great advantage is that it is simple, automatic, and can be extended to automatic detection of bacterial sensitivity to antibiotics.
Preservation of Enteroviruses by Freeze-Drying
Authors: Berge Trygve O. , Jewett Ronald L. , Blair William O.
Published: December 2020

A method was developed for freeze-dry stabilization of poliovirus type 3. An ultrafiltration procedure was used to remove salts from infected tissue culture fluid, and the virus was freeze-dried after suspension in an alkaline organic buffer. This method was further tested with other picornaviruses including poliovirus types 1 and 2, coxsackieviruses A9, A20, B2, and B5, echovirus 11, and the encephalomyocarditis virus. Freeze-dried preparations of the poliovirus could be shipped to distant laboratories at ambient temperature with excellent retention of infectivity. Data are presented showing effects of freeze-drying as well as results of exposure to temperatures to 37 C.
Clostridium perfringens
Authors: Clifford Walter J. , Anellis Abe
Published: December 2020

A biphasic culture medium suitable for cultivation and sporulation of
Clostridium perfringens, C. botulinum
, and
C. sporogenes
was devised. The medium designed for use in a disposable, compartmented, plastic film container contained peptones, yeast extract, minerals, an anion exchange resin, and glucose in 4% agar as the solid phase and (NH
4
)
2
SO
4
and 0.1% agar as the liquid phase. With the biphasic system, it was not necessary to use active cultures as inocula. Growth was at least equal to that obtained in conventional media, and spore production of 9 out of 12 strains of
C. perfringens
equalled or usually exceeded that of conventional media.
Interpretation of Diffusion Susceptibility Data Obtained with 50-μg Carbenicillin Discs Against Gram-Negative Organisms
Authors: Traub Walter H. , Raymond Ella A.
Published: December 2020

A total of 284 clinical isolates of various species of
Enterobacteriaceae, Pseudomonas aeruginosa, P. maltophilia
, and
Acinetobacter anitratum
were tested for susceptibility to carbenicillin by the standardized Bauer-Kirby disc diffusion technique and a microtiter broth dilution method. The data obtained led to the following proposed criteria for the interpretation of the results of disc susceptibility tests.
Enterobacteriaceae
that yield zones of inhibition equal to or greater than 20 mm in diameter around 50-μg discs of carbenicillin are designated as sensitive to the drug; isolates that yield zones measuring from 18 to 19 mm in diameter are reported as of equivocal (intermediate) susceptibility to the drug, whereas those enterobacterial isolates that are characterized by zones of inhibition of 17 mm or less in diameter are interpreted as resistant to carbenicillin. Isolates of
P. aeruginosa, P. maltophilia
, and
A. anitratum
yielding zones of 14 mm or more in diameter around 50-μg discs of carbenicillin are reported as sensitive, whereas those isolates that are characterized by zones of 13 mm or less in diameter are reported as resistant to this drug.
Susceptibility of Recent Isolates of
Pseudomonas aeruginosa
to Gentamicin, Polymyxin, and Five Penicillins, with Observations on the Pyocin and Immunotypes of the Strains
Authors: Adler Jonathan L. , Finland Maxwell
Published: December 2020

The susceptibilities of recently isolated strains of
Pseudomonas aeruginosa
to gentamicin, polymyxin B, carbenicillin, ampicillin, penicillin G, and two newer penicillins were tested with the inocula-replicating technique by using undiluted and 10
−3
dilutions of the cultures. With either inoculum, polymyxin B was the most active agent, and a comparison with previous data from this laboratory showed that the susceptibility of
P. aeruginosa
to this antibiotic had not changed over the past 20 years. Gentamicin was nearly as active as polymyxin, all but 2 of the 141 strains tested with the diluted inoculum being inhibited by 6.25 μg/ml or less. AB-2288, an agent resembling carbenicillin, was four times more active than carbenicillin or BLP-1654; the last two were equally active against the 10
−3
inoculum. A more marked inoculum effect was noted with the penicillin analogues tested, the increase in minimum inhibiting concentration with the undiluted culture being eight-fold for carbenicillin and at least 16-fold for AB-2288 and BLP-1654. Pyocin typing and serotyping failed to demonstrate any clearly predominating types.
Preparation and Testing of Polyvalent Conjugates for Fluorescent-Antibody Detection of Salmonellae
Authors: Thomason Berenice M. , Wells Joy G.
Published: December 2020

A polyvalent OH conjugate for
Salmonella
O groups A through I, K, L, and O was prepared and tested against pure cultures of salmonellae, nonsalmonellae, and a variety of food, fecal, and environmental specimens. Examination of pure cultures revealed that the conjugate gave negligible staining with representative strains of
Shigella, Proteus, Providence, Serratia
, and
Pseudomonas
. However, it stained 12% of the
Escherichia coli
and
Citrobacter freundii
strains and 36% of the
Arizona
strains. Over 1,200 specimens of various types were examined by both fluorescent-antibody (FA) and cultural procedures. Results indicate that, when used with discretion, FA screening can be a useful tool for rapid presumptive indication of the presence of salmonellae. The need for careful selection of strains used for preparing antisera and the importance of adequate evaluation of
Salmonella
FA reagents are discussed.
Aerosol Inoculator for Exposure of Human Volunteers
Authors: Gerone Peter J. , Couch Robert B. , Knight Vernon
Published: December 2020

The performance of an aerosol inoculator for human volunteers is described in tests that used the PR8 strain of type A influenza virus and sodium fluorescein as a physical tracer. Virus recovery from the aerosols was approximately 1% and was unaffected by such variables as prolonged aerosolization, total airflow, relative humidity, or method of sampling. The recovery of sodium fluorescein from the aerosol was approximately 12% and was influenced by total airflow rates and relative humidity. With this apparatus, it should be possible to deliver reasonably predictable and measurable doses of respiratory viruses to human subjects. The design makes it possible to dismantle the inoculator into its component parts to facilitate portability.
Virus-Like Particles in
Cephalosporium acremonium
Authors: Day L. E. , Ellis L. F.
Published: December 2020

Cephalosporium acremonium
cultures were studied for the presence of virus-like particles. Relatively few particles were found in the preparations, indicating that the number of particles present in these cells may be much lower than in
Penicillium
species.
Growth Factor Requirements of Ruminal Cellulolytic Bacteria Isolated from Microbial Populations Supplied Diets With or Without Rapidly Fermentable Carbohydrate
Authors: Slyter L. L. , Weaver J. M.
Published: December 2020

The predominant cellulolytic ruminal bacteria isolated from microbial populations supplied diets containing cellulose as an energy source and essentially devoid of amino acids or rapidly fermentable carbohydrates were shown to require branched-chain acid(s) for growth.
Distribution of
Sorangium cellulosum
Authors: Lampky J. R.
Published: December 2020

The myxobacterium
Sorangium cellulosum
exists and plays an important role in soil ecology by its ability to degrade cellulosic materials; it was found to be widely distributed in North American soils.
Selective Medium for the Isolation of Streptococci from Clinical Specimens
Authors: Vincent William F. , Gibbons William E. , Gaafar Hassan A.
Published: December 2020

Incorporating neomycin and nalidixic acid into a blood-agar base resulted in a medium highly selective for beta-hemolytic streptococci under conditions in which detection of streptococcal colonies by conventional means would have been very difficult.
Enhancing Effects of Carbon Dioxide on the Primary Isolation of Acid-Fast Bacilli in a Modified Lowenstein-Jensen Medium
Authors: Gruft Howard , Loder Arthur
Published: December 2020

Specimens inoculated on modified Lowenstein-Jensen medium were incubated aerobically and in an atmosphere of 8% CO
2
. Sixteen per cent of the positive specimens grew
Mycobacterium tuberculosis
only after incubation in CO
2
.
Decontamination of Microbiological Incubators
Authors: Furness Geoffrey
Published: December 2020

A practical method of employing moist heat for the elimination of bacterial and fungal contaminants in microbiological incubators is described.
Minimal Growth Temperature, Sodium Chloride Tolerance,
p
H Sensitivity, and Toxin Production of Marine and Terrestrial Strains of
Clostridium botulinum
Type C
Authors: Segner W. P. , Schmidt C. F. , Boltz J. K.
Published: December 2020

Minimal growth temperatures of four marine and two terrestrial strains of
Clostridium botulinum
type C were determined in a laboratory culture medium, fortified egg meat medium (FEM), and in ground haddock. The inoculum equaled 2 × 10
6
viable spores per tube with five-tube replicate sets. The spores were preheated in aqueous suspension at 71 C for 15 min prior to inoculation to reduce toxin carry-over. Similar results were obtained in both substrates. Both the marine and the terrestrial strains grew at 15.6 C, but only the terrestrial strains grew at 12.8 C. None of the strains grew at 10 C during prolonged incubation. The sodium chloride tolerance and the
p
H sensitivity of the marine and the terrestrial strains were determined at 30 C. The basal medium consisted of beef infusion broth. The inoculum level equaled 2 × 10
6
unheated spores per replicate. Growth was inhibited at salt concentrations from 2.5 to 3.0%. The terrestrial strains were more
p
H-sensitive than the marine strains. Whereas the terrestrial strains failed to grow below
p
H 5.62, three of the marine strains grew at
p
H 5.10, but not at
p
H 4.96, during extended incubation. One marine strain grew at
p
H 5.25, but not below. FEM and proteose peptone-Trypticase-yeast extract-glucose medium permitted the production of high levels of botulinum toxin among four media tested. Toxin produced by the marine and terrestrial strains showed no increase in toxicity after incubation with trypsin.
Effect of
p
H, Protein Concentration, and Ionic Strength on Heat Inactivation of Staphylococcal Enterotoxin B
Authors: Jamlang E. M. , Bartlett M. L. , Snyder H. E.
Published: December 2020

Heat treatment of highly purified staphylococcal enterotoxin B causes a more rapid loss of immunological activity at 70 to 80 C than at 90 to 100 C. Toxicological results based on intravenous injection of dogs paralleled the results obtained by immunological means (single gel diffusion). The loss of immunological activity did not follow first-order kinetics. Results are given on the effects on heat inactivation of changing
p
H, ionic strength, and initial concentration of enterotoxin. Disc-gel electrophoresis of purified enterotoxin B showed a major and minor band. The minor band was a size isomer of the major band.
Intracellular Proteases of
Bacillus stearothermophilus
Authors: Feder Joseph , Ladenburg Kurt , Delente Jacques , Wildi B. S.
Published: December 2020

Cell-free extracts of
Bacillus stearothermophilus
have been shown to exhibit proteolytic activity toward casein as well as specific activity to catalyze the hydrolysis of furylacryloylglycyl-
l
-leucine amide, furylacryloylglycine, and carbobenzoxyl-glycine-
p
-nitrophenyl ester, indicating the presence of a neutral proteinase, a carboxypeptidase-like enzyme, and an alkaline proteinase. The neutral proteinase and carboxypeptidase-like activities were separated by gel filtration over Bio-Gel P-60, and both were reversibly inhibited by 1, 10-phenanthroline. The esterase activity was inhibited by diisopropylfluorophosphate, which did not affect other enzymatic activities and was insensitive to 1, 10-phenanthroline and ethylenediaminetetra-acetic acid.
Rapid Detection of
Salmonella
Microcolonies by Fluorescent Antibody
Authors: Thomason Berenice M.
Published: December 2020

A microcolony fluorescent-antibody (FA) procedure for detecting salmonellae was compared to the usual direct FA procedure on 304 environmental, food, and feed samples. The microcolony FA test detected all of the specimens found positive by culture, whereas the direct FA missed 3.1% of them. Both FA tests revealed stained organisms in some of the culturally negative specimens. The microcolony FA test has several advantages over the direct FA test: ease of examining the smears, elimination of the fluorescent background material, and increased sensitivity.
Cell Line Derived from a Murine Sarcoma Virus (Moloney Pseudotype)-Induced Tumor: Cultural, Antigenic, and Virological Properties
Authors: Massicot J. G. , Woods W. A. , Chirigos M. A.
Published: December 2020

A cell line derived from a murine sarcoma virus (Moloney pseudotype)-induced tumor has been established. It retains oncogenicity, releases both sarcoma and leukemia viruses, and has virus-induced cellular antigens.