bluuebunny/crossref_metadata_2025 huggingface dataset:
Unusual
Sphaerophorus
Species from the Large Intestine of Man
Authors: Pearson Ted A. , Balish Edward
Published: December 2020

An obligately anaerobic, gram-negative microorganism identified as a
Sphaerophorus
species was recovered from the fecal material of two cancer (chronic myelogenous leukemia and idiopathic thrombocythemia) patients receiving cobalt radiation therapy. The organism, isolated on sheep blood-agar, exhibited extreme pleomorphism (rods, filaments, and spheroids) and was a major component of the anaerobic fecal microflora. In one patient the numbers of
Sphaerophorus
species (designated as isolate 6-13-68),
Bacteroides
species, and
Clostridium perfringens
declined after irradiation; however, they were stable in this same patient after a second therapeutic dose of radiation. The numbers of anaerobes in the other patient remained fairly consistent after radiation. The biochemical and morphological characteristics and carbohydrate fermentation reactions of isolate 6-13-68 most closely resembled those of
Sphaerophorus ridiculosis
.
Action of Diethylstilbestrol on Staphylococci: Further Observations on the Effect of Resting Cells
Authors: Yotis William W. , Baman Sudhaker I.
Published: December 2020

Diethylstilbestrol (DS) has been shown to be active against staphylococci and other gram-positive bacteria but not against gram-negative microorganisms. The present study extends these findings. Standardized suspensions of
14
C-labeled
Staphylococcus aureus
serotypes III and IV and
Shigella flexneri
were prepared and exposed to pharmacological concentrations of DS (1 to 20 μg/ml) under diverse environmental conditions; the cells were removed by membrane filtration and the presence of radioactive substances in release to the supernatant fraction was followed by standard radioisotopic techniques. Controls were exposed similarly to the hormone vehicle alone (buffer containing 2% ethyl alcohol). DS at bactericidal concentrations above 6 μg/ml caused significant leakage of cellular radioactivity of
S. aureus
labeled with
14
C-glucose and
14
C-glutamic acid within 1 to 4 hr after exposure to DS. Maximum leakage of radioactivity occurred under anaerobic conditions at 37 C. Absorption studies of
14
C-labeled DS indicated that the affinity of
S. flexneri
for DS is markedly less than that of
S. aureus
. This might be one reason for the resistance of gram-negative bacteria to DS.
Effect of Four Organophosphorus Insecticides on Microbial Activities in Soil
Authors: Tu C. M.
Published: December 2020

Laboratory tests were conducted with four organophosphorus insecticides, Bay 37289 (
O
-ethyl
O
-2,4,5-trichlorophenyl ethylphosphonothioate), diazinon [
O
,
O
-diethyl
O
-(2-isopropyl-4-methyl-6-pyrimidinyl) phosphorothioate], Dursban (
O
,
O
-diethyl
O
-3,5,6-trichloro-2-pyridyl phosphorothioate), and Zinophos (
O
,
O
-diethyl
O
-2-pyrazinyl phosphorothioate), applied to a sandy loam at rates of 10 and 100 μg/g to determine whether these materials caused any serious effects on microbial activities related to soil fertility. All insecticides showed an effect on fungi and bacteria for the first and second week of incubation, but, subsequently, the populations returned to levels similar to those obtained in the controls. All insecticide applications increased ammonium production, but, in some instances, there appeared to be a slight depression of nitrification. Sulfur oxidation was equal to or better than that obtained with untreated soil in most cases. There was no significant effect on phosphorus mineralization. Oxygen consumption indicated that microbial respiration increased in proportion to the concentration of insecticides, suggesting the possibilities of microbial degradation of the insecticides or their degradation products and of uncoupling oxidative phosphorylation.
Microbiological Assay and Tissue Distribution of β-Thioguanine Deoxyriboside in Mice
Authors: Pittillo Robert F. , Woolley Carolyn
Published: December 2020

A sensitive, precise microbiological assay has been developed for the determination of tissue distribution of β-thioguanine deoxyriboside, a new antitumor agent.
Adaptation of a Roller-Tube Apparatus to Accommodate Cultivation of Cells in Roller-Bottles
Authors: Rogers Joseph L. , Orr Henry C.
Published: December 2020

We have adapted the standard roller-tube apparatus to production of large scale cell culture by modifying the drum to accept bottles.
Cell-Associated Nature of Cottontail Rabbit Herpesvirus In Vitro
Authors: Ley Kenneth D. , Burger Dieter
Published: December 2020

The cottontail rabbit herpesvirus is presently classified in subgroup A of the herpesviruses, whereas the virus is strongly cell associated and belongs in subgroup B.
Chemical States of Bacterial Spores: Heat Resistance and Its Kinetics at Intermediate Water Activity
Authors: Alderton Gordon , Snell Neva
Published: December 2020

Bacterial spore heat resistance at intermediate water activity, like aqueous and strictly dry heat resistance, is a property manipulatable by chemical pretreatments of the dormant mature spore. Heat resistances differ widely, and survival is prominently nonlogarithmic for both chemical forms of the spore. Log survival varies approximately as the cube of time for the resistant state of
Bacillus stearothermophilus
spores and as the square of time for the sensitive state. A method for measuring heat resistance at intermediate humidity was designed to provide direct and unequivocal control of water vapor concentration with quick equilibration, maintenance of known spore state, and dispersion of spores singly for valid survivor counting. Temperature characteristics such as z, E
a
, and Q
10
cannot be determined in the usual sense (as a spore property) for spores encapsulated with a constant weight of water. Effect on spore survival of temperature induced changes of water activity in such systems is discussed.
Naphthylamidase Activity of
Leptospira
Authors: Burton Glenna , Blenden D. C. , Goldberg H. S.
Published: December 2020

Extracts of 18 serotypes of the genus
Leptospira
were found to possess naphthylamidase activity, and differences in the pathogenic and saprophytic strains were noted. The former exhibited a preference for the leucyl naphthylamide substrate, whereas the latter demonstrated greater hydrolysis of alanyl naphthylamide. With the leucyl naphthylamide as substrate, pathogenic strains showed 10 to 20 times higher naphthylamidase activity than saprophytic strains. Optimal temperature and
p
H for enzymatic hydrolysis also differed between pathogenic and saprophytic strains. Maximal enzymatic activities for pathogenic and saprophytic naphthylamidases were 41 and 37 C, respectively, at
p
H 8.0 to 8.5. The
p
H and temperature optima suggested that the leptospiral enzyme activity was not leucine aminopeptidase.
Mycotoxicity of
Aspergillus ochraceus
to Chicks
Authors: Doupnik Ben , Peckham John C.
Published: December 2020

Five isolates of
Aspergillus ochraceus
, obtained from peanuts, were grown separately on sterile, moist corn for 14 days and fed to 1-day-old Babcock B-300 cockerels to evaluate their toxic effects. Two isolates were highly toxic, causing death of all birds during the 1st week of the experiment. Two isolates were moderately toxic, causing severe growth suppression with some deaths occurring throughout the 3-week test period. One isolate had no apparent effect. When the two most toxic isolates (diets) were diluted, survival time increased but severe growth suppression was evident. Postmortem examinations revealed a few small hemorrhages in the proventriculi of birds which died between the 2nd and 5th days. Emaciation, dehydration, and dry, firm gizzard linings were observed throughout the experiment. Extensive hepatic injury consisting of either fatty changes or necrotic foci was the principal microscopic finding. Suppression of bone marrow activity and depletion of lymphoid elements in the spleen and bursa of Fabricius were also found. The severity of the histopathological changes was directly related to the concentration of ochratoxin A in the diets.
Production of Rubratoxin B by
Penicillium purpurogenum
Stoll
Authors: Natori Shinsaku , Sakaki Setsuko , Kurata Hiroshi , Udagawa Shun-Ichi , Ichinoe Masakatsu , Saito Mamoru , Umeda Makoto , Ohtsubo Kohichiro
Published: December 2020

Culture filtrates and chloroform extracts from
Penicillium purpurogenum
isolated from foodstuffs were subjected to preliminary survey for toxic effects on HeLa cells and mice. The toxic metabolite was isolated in a crystalline form from
P. purpurogenum
and was identified as rubratoxin B. Pathological findings observed in HeLa cells and mice treated with the metabolite are briefly described.
Effect of Spermine on Host-Cell Lysis and Reproduction by a Lactic Streptococcal Bacteriophage
Authors: Erskine J. M.
Published: December 2020

A method was tested for protecting a
Streptococcus lactis
strain, ML3, used as a starter in the manufacture of Cheddar cheese, against the lytic activity of its homologous phage, ml
3
. At a concentration of 10
−2
m
, a naturally occurring polyamine, spermine, in the form of its hydrochloride, protected ML3 against lysis-from-without and lysozyme activity and against lysis by the phage when added at the time of infection or up to 21 min after infection. It was found that the latter protective effect could be accounted for in terms of the spermine preventing the formation of mature particles rather than preventing the escape of viable phage. Single colonies selected from a culture of ML3 cells that had been previously infected with phage ml
3
, in the presence of spermine, were all found to have acquired resistance to phage ml
3
. They retained this resistance during a 3-month period of daily subculture in broth and, in the absence of spermine, could not be induced to liberate phage or phage components either by the techniques normally used for inducing lysogens or by artificial disruption of the cells. It is concluded that when spermine is added to ML3 cells before a certain critical stage of the phage infection cycle, the process of phage synthesis is irreversibly halted and the cells retain the infecting phage as a defective prophage that confers on the cells immunity to infection by the homologous phage. Phage-resistant cultures did not inherit reduced starter activity in association with their acquired resistance characteristic.
Aerobic Heterotrophic Bacterial Populations of Sewage and Activated Sludge
Authors: Prakasam T. B. S. , Dondero N. C.
Published: December 2020

Two procedures, the confidence interval method and Mountford's index, were tested in analyses of the microbial populations of 11 laboratory activated sludges acclimated to aromatic compounds. The two methods gave somewhat different results but indicated that the populations were quite dissimilar. The activity of seven of the sludges correlated well with the population structure. Some considerations in analysis of microbial population structure are discussed.
Degradation of Urea Herbicides by Cell-Free Extracts of
Bacillus sphaericus
Authors: Walln�fer P. R. , Bader J.
Published: December 2020

N′
-methoxy phenylurea herbicides are degraded by induced cells of
Bacillus sphaericus
ATCC 12123 by liberating carbon dioxide from the ureido portion of the molecule and leaving the corresponding aniline moieties. Cell-free extracts of
B. sphaericus
inactivate these herbicides in the same way as reported for whole cells. A 6.6-fold purification of the crude extract was achieved by a combination of salt fractionation with ammonium sulfate and column chromatography on diethyl-aminoethyl cellulose.
Persistence of an
Escherichia coli-Shigella flexneri
Hybrid in the Intestinal Tract of
Macaca mulatta
Authors: Wynne E. Staten , Henrikson Duane M. , Daye George T.
Published: December 2020

A live oral vaccine prepared from an
Escherichia coli-Shigella flexneri
4b hybrid was administered by gavage to
Macaca mulatta.
In the three main studies involving 160 monkeys, three doses were used, generally consisting of 5 � 10
9
to 60 � 10
9
cells per dose, with an interval between doses of 6, 7, or 14 days. Rectal swab cultures at the time of the last vaccine dose, and 14 to 58 days later, revealed that the hybrid persisted in the intestinal tract for at least 7 days in 16%, and for at least 21 days in 8%, of the monkeys. Our findings are comparable to those of Formal et al. for shedding of an
E. coli-S. flexneri
2a hybrid. Protection studies with the
E. coli-S. flexneri
4b hybrid are indicated.
Bacteriological and Shelf-Life Characteristics of Canned, Pasteurized Crab Cake Mix
Authors: Loaharanu Paisan , Lopez Anthony
Published: December 2020

The bacteriological spoilage characteristics of a canned, pasteurized crab cake mix product stored at various temperatures were investigated. A large number of bacteria, both mesophilic and psychrophilic, survived the pasteurization process.
Bacillus
and
Micrococcus
were found to predominate when the product was stored at 30 C (86 F) and 18 C (64 F), whereas
Alcaligenes
predominated at 2 C (36 F). The product was found to be free of
Escherichia coli.
Bacterial counts, trimethylamine nitrogen, volatile reducing substances, and ammonia determinations were evaluated as indices of quality for the product. Close correlation was observed between bacterial counts, volatile reducing substance values, and organoleptic tests when the product was stored at 30 C (86 F). The shelf-life of the product was approximately 6 months at 2 C (36 F), 4 days at 18 C (64 F), and 27 hr at 30 C (86 F).
Gamma-Irradiated Venezuelan Equine Encephalitis Vaccines
Authors: Reitman Morton , Tribble H. R. , Green Leonard
Published: December 2020

The efficacy of Formalin-inactivated Venezuelan equine encephalitis (VEE) vaccine has been reported to be low for man. Although a live VEE vaccine has been shown to be highly effective for the protection of laboratory workers, local and systemic reactions have occurred in approximately 20% of inoculated individuals. Therefore, studies were initiated in an attempt to produce an inactivated vaccine of high potency with low toxicity. Inactivated VEE vaccines were prepared by exposing virus suspensions to 8 � 10
6
or 10 � 10
6
r of gamma radiation. Irradiated VEE vaccines prepared from virus suspensions produced in Maitland-type chick embryo (MTCE) cell cultures and in monolayer cultures of human diploid strain WI-38 cells were highly immunogenic for mice and guinea pigs. Guinea pigs vaccinated with a series of three inoculations of vaccine (MTCE) survived challenge with at least 10
8�4
mouse intracerebral 50% lethal doses of VEE virus. Irradiated vaccines induced high levels of serum-neutralizing and hemagglutinin-inhibiting antibodies in guinea pigs and rabbits. These findings suggest that ionizing radiation may be effective in the preparation of an inactivated VEE vaccine.
Histopathology of
Listeria monocytogenes
After Oral Feeding to Mice
Authors: Miller John K. , Burns Jean
Published: December 2020

Ingestion by mice of
Listeria monocytogenes
in drinking water induced micro-abscesses of the liver and ulcerative enteritis. In pregnant mice, these lesions were larger and more extensive than in nonpregnant female and male mice. Pregnancy is interrupted by a purulent panmetritis and necrotizing placentitis. The early microabscess is unique in that it consists of monocytic cells with bizarre-shaped nuclei. The experimentally induced pathological changes in livers and intestines of mice used in this study are similar to those observed in listeric neonatal septicemia of human infants.
Effects of Moisture Content and Temperature on Aflatoxin Production in Corn
Authors: Trenk Hugh L. , Hartman Paul A.
Published: December 2020

Samples of freshly harvested and remoistened corn, of various moisture contents, were stored at different temperatures; analyses for aflatoxin content were made periodically. At moisture levels above 17.5% and at temperatures of 24 C or warmer, aflatoxins were formed by
Aspergillus flavus
present in the original epiphytic mycoflora. Remoistened dried corn was subject to more rapid fungal deterioration and aflatoxin formation than freshly harvested corn. Screening of the fungi present in the corn revealed aflatoxin production only by
A. flavus
. The toxigenic strains produced only aflatoxins B
1
and B
2
.
Salmonella
Contamination in a Poultry-Processing Plant
Authors: Morris George K. , Wells Joy G.
Published: December 2020

Bacteriological examination of 1,427 samples from a poultry-processing plant over a 2-year period yielded 202 (14.2%) cultures positive for salmonellae. The results indicate that contamination is reduced by washing procedures within the plant but that recontamination of the carcasses occurred in at least two different stages of processing, i.e., during evisceration and chilling. There was evidence of spread of salmonellae from flock to flock during the serial processing of flocks, but the spread was usually not extensive. The serotypes of salmonellae isolated in this study were similar to those of chicken origin reported from other areas of the country.
Influence of Dissolved Oxygen Levels on Production of
l
-Asparaginase and Prodigiosin by
Serratia marcescens
Authors: Heinemann Bernard , Howard Alma J. , Palocz Henry J.
Published: December 2020

The effect of dissolved oxygen concentrations on the behavior of
Serratia marcescens
and on yields of asparaginase and prodigiosin produced in shaken cultures and in a 55-liter stainless-steel fermentor was studied. A range of oxygen transfer rates was obtained in 500-ml Erlenmeyer flasks by using internal, stainless-steel baffles and by varying the volume of medium per flask, and in the fermentor by high speed agitation (375 rev/min) or low rates of aeration (1.5 volumes of air per volume of broth per min), or both. Dissolved oxygen levels in the fermentation medium were measured with a membrane-type electrode. Peak yields of asparaginase were obtained in unbaffled flasks (3.0 to 3.8 IU/ml) and in the fermentor (2.7 IU/ml) when the level of dissolved oxygen in the culture medium reached zero. A low rate of oxygen transfer was accomplished by limited aeration. Production of prodigiosin required a supply of dissolved oxygen that was obtainable in baffled flasks with a high rate of oxygen transfer and in the fermentor with a combination of high-speed agitation and low-rate aeration. The fermentation proceeded at a more rapid rate and changes in
p
H and cell populations were accelerated by maintaining high levels of dissolved oxygen in the growth medium.
Somatic Antigens of
Streptococcus
Group E
Authors: Payne Jerry B. , Armstrong Charles H.
Published: December 2020

Antigenic extracts of
Streptococcus
group E (SGE) were subjected to fractional ethanol precipitation, block (preparative) electrophoresis, and gel filtration for the purpose of separating the type antigen from the group antigen. Ethanol precipitation was ineffective in separating the substances. Block electrophoresis yielded serologically pure group antigen and a mixture of type and group antigen. Serologically pure type antigen was obtained by gel filtration. In some cases, pure group antigen was also recovered; in others, it was contaminated with type antigen. Gel filtration column effluents of antigenic extracts of SGE serotypes, I, II, III, IV, V and “untypable” isolates, collected from the region in which type antigen was eluted, were studied by paper chromatography and infrared spectrophotometry in an effort to develop a nonserological means of detecting type antigen. Hydrolysates of type antigens or suspect type antigens of serotypes I through V contained
l
-rhamnose,
d
-glucose, and several unidentified substances.
d
-Galactose also was present in hydrolysates of serotypes III and V. Untypable isolates and negative controls contained traces of
d
-glucose only. The data suggested that serotypes I through V contained a type antigen and that the untypable isolates were devoid of type antigen. Infrared absorbance spectra seemed to support the paper chromatography data.
Thermoelectrically Cooled Temperature-Gradient Apparatus for Comparative Cell and Virus Temperature Studies
Authors: Clark H. F. , Kaminski F. , Karzon D. T.
Published: December 2020

Establishment of a near-linear temperature gradient in an incubator has been accomplished by the application of heat to one terminus of a conducting body, normally a metal bar, and the removal of heat from the other terminus of the conducting body. Such incubators have been complex and unwieldy because of the need for mechanical refrigeration. We have described a simplified temperature gradient incubator which uses thermoelectric module cooling coupled with electric heating. Along the gradient, 20 stations in two parallel rows of 10, each accommodating a 30-ml plastic cell culture flask, were continually monitored by an electronic thermometer, and the temperatures were recorded. By manipulation of two simple potentiometer controls, any temperature gradient between 0 and 50 C could be obtained. Minor deviations which occurred between theoretically perfect and obtained temperature gradients were reproducible and readily measured. The gradient incubator was particularly applicable to (i) simultaneously studying a given biological activity over the entire temperature range supporting the growth of a given cell, virus, or microorganism, or (ii) precisely defining the upper or lower temperature limits of a biological system by 10-point determinations. Preliminary experiments have demonstrated the usefulness of the apparatus in characterizing the temperature limits for growth in vitro of cells of reptilian cell lines. The gradient incubator was also successfully utilized for the characterization of the effect of temperature on the efficiency of plating of amphibian viruses and possible temperature variants of those viruses.
Recovery of Airborne Streptococcal L-Forms at Various Relative Humidities
Authors: Stewart R. H. , Wright D. N.
Published: December 2020

Aerosolized group A streptococcal L-forms survived better at low than at high relative humidities, and mid-range humidities were the most lethal. Colonial morphology of cells surviving aerosolization was not altered.
Degradation of Endrin, Aldrin, and DDT by Soil Microorganisms
Authors: Patil K. C. , Matsumura F. , Boush G. M.
Published: December 2020

Twenty microbial cultures which had been shown to degrade dieldrin were tested to determine their ability to degrade endrin, aldrin, DDT, gamma isomers of benzenehexachloride (γ-BHC), and Baygon. All isolates were able to degrade DDT and endrin, whereas 13 degraded aldrin. However, none of them was able to degrade Baygon or γ-BHC.
Laboratory Measure of an Ecosystem Response to a Sustained Stress
Authors: Coler Robert A. , Gunner Haim B.
Published: December 2020

A new method is described for measuring environmental stress through the use of the duckweed (
Lemna minor
) rhizosphere.
Device for Turbidity Standardizing of Cultures for Antibiotic Sensitivity Testing
Authors: Stemper Joanne E. , Matsen John M.
Published: December 2020

A specially designed metal rack which is illuminated by a modified Rh-typing view box is described. This device facilitates the handling and reduces the time involved in standardizing cultures.
Antibacterial Effect of Some Azaphenanthrene Compounds
Authors: Gupta K. G. , Kessar S. V. , Singh Baldev
Published: December 2020

Five newly synthesized azaphenanthrene compounds have been studied for their antibacterial activity, which to varying degrees was shown to be related to the position of the aza, methyl, and benzyl groups in the ring.
Dubos Oleic Acid Agar Medium in the Differentiation of Meningococci and Gonococci
Authors: Diena B. B. , Wallace R. , Kenny C. P. , Greenberg L.
Published: December 2020

Growth on Dubos oleic acid agar plates, incubated for 48 hr at 37 C in candle jars, provides a method for differentiating meningococci from gonococci. All of our 54 strains of meningococci, but none of the 49 strains of gonococci, grew on this medium.
Enzymatic Removal of Diacetyl from Beer
Authors: Thompson Janet W. , Shovers J. , Sandine W. E. , Elliker P. R.
Published: December 2020

Use of diacetyl reductase, a reduced nicotinamide adenine dinucleotide (NADH)-requiring enzyme, to eliminate diacetyl off-flavor in beer was studied. The crude enzyme was extracted from
Aerobacter aerogenes
and partially purified by ammonium sulfate precipitation or Sephadex chromatography. In the semipure state, the enzyme was inactivated by lyophilization; in a crude state, the lyophilized extract remained stable for at least 4 months at — 20 C. A 50% reduction in specific activity within 5 min was observed when crude diacetyl reductase was suspended (5 mg of protein/ml) in phosphate buffer at
p
H 5.5 or below; a similar inactivation rate was observed when the crude enzyme was dissolved in a 5% aqueous ethyl alcohol solution. Effective crude enzyme activity in beer at a natural
p
H of 4.1 required protection of the enzyme in 10% gelatin. Incorporation of yeast cells with the gel-protected enzyme provided regeneration of NADH. Combinations of yeast, enzyme, and gelatin were tested to obtain data analyzed by regression analysis to determine the optimal concentration of each component of the system required to reduce the level of diacetyl in spiked (0.5 ppm) beer to less than 0.12 ppm within 48 hr at 5 C. The protected enzyme system was also effective in removing diacetyl from orange juice (
p
H 3.8) and some distilled liquors.
Use of a Titrimetric Method to Assess the Bacterial Spoilage of Fresh Beef
Authors: Shelef Leora A. , Jay James M.
Published: December 2020

A new method of determining bacterial spoilage in fresh beef is presented. The technique is based upon the fact that as beef undergoes refrigerator spoilage, there is a gradual increase in the production of alkaline substances by the spoilage flora. The level of these substances was measured by titrating meat homogenates to a
p
H 5.00 end point, employing 0.02
n
HCl and an autotitrator. When 23 samples of ground beef from retail stores were tested, an average of 1.32 ml of acid was required for titration of 1 g of fresh beef to
p
H 5.00, whereas 2.58 ml was required for the same meat at the onset of spoilage. Preliminary data indicate that beef which requires more than 2 ml of 0.02
n
HCl/g to lower its
p
H to 5.00 under the conditions of the test is in some state of incipient spoilage. The statistical correlation between titration values, log bacterial numbers, and extract-release volume was high (
P
< 0.001). The technique is simple to execute and is highly reproducible, and duplicate samples can be run within 15 min.
Relationship Between Staphylococcal Antiserum Titer and Zone Development on Immune Serum Plates
Authors: Weiss K. F. , Robbins Ruth N.
Published: December 2020

A workable relationship was established between the standard serum titers of staphylococcal immune antisera and the development of precipitin zones on serum agar around colonies of staphylococcal strains producing homologous antigens (enterotoxins). The standard titer of a serum is defined as the reciprocal of that serum dilution which, with 10 μg of pure enterotoxin per ml, will give a precipitin zone 10 mm in length in single gel-diffusion tubes after 7 days of incubation at 25 C. A numerical scale was set up for determining the intensity of precipitin zones on serum agar. A reading of 3 was considered optimum. This correlated well with a standard serum titer of 25, when 1 ml of such a serum was used per 20 ml of medium per serum plate. From this relationship, the minimum volume of serum required to give optimum precipitin zone development can be calculated.
Pesticinogeny: a Characteristic Useful for Presumptive Identification and Isolation of
Pasteurella pestis
Authors: Beesley Earl D. , Surgalla Michael J.
Published: December 2020

Current methods of identifying
Pasteurella pestis
rely heavily on tests specific for detecting fraction I, the envelope antigen. Pesticin I, a bacteriocin inhibitory for
P. pseudotuberculosis
, has been demonstrated in nearly all tested strains isolated from human infections. The results of using this characteristic as an identifying trait for
P. pestis
were compared with results reported for detecting fraction I by fluorescent-antibody and antiserum-agar techniques. Data indicate that, although certain atypical strains of
P. pestis
fail to react in one system or the other, a combination of these tests provides positive identification in all cases. Detection of
P. pestis
in contaminated materials is greatly facilitated, and the simplicity of this test makes it a valuable tool in the study of plague infections and an important adjunct to methods currently in use. The use of the pesticin I assay is not intended to replace other accepted techniques, but rather to supplement them and increase the effectiveness of plague investigation.
Identification of Staphylococci Isolated from Clinical Material
Authors: Raymond E. A. , Traub W. H.
Published: December 2020

A total of 350 staphylococci isolated from various clinical sources were examined for bound and free coagulase, fermentation of mannitol, and deoxyribonuclease. The economical coagulase-mannitol-agar method of Esber and Faulcomer was found to be suitable for the detection of free coagulase and mannitol fermentation. A significant number of coagulase- and mannitol-negative staphylococci proved to be deoxyribonuclease-positive.
Purified Rabies Vaccine (Suckling Rat Brain Origin)
Authors: Lavender J. F.
Published: December 2020

A 10% suckling rat brain rabies vaccine free from encephalitogenic activity was prepared and inactivated with 1:8,000 beta-propiolactone (BPL), or ultraviolet light, or a combination of ultraviolet light and BPL, or 1% phenol. Potency was excellent in all samples, with the exception of the phenolized product which was marginal. A purified suckling rat brain (SRB) vaccine prepared by zonal centrifugation and inactivated with 1:8,000 BPL contained about 0.01 the amount of protein nitrogen of the unpurified 10% SRB vaccine. This purified product passed the National Institutes of Health potency test for rabies vaccine after administration of a quantity equivalent to a standard 10% brain suspension.
Studies of Laryngotracheitis Virus in Avian Tissue Cultures
Authors: Rossi C. R. , Watrach A. M.
Published: December 2020

Diethylaminoethyl-dextran (DEAE-D) enhanced the infectivity of laryngotracheitis virus (LTV) for chicken kidney (CK) cells when cultures were treated before inoculation with virus and when DEAE-D was present in the inoculum. Infectivity was not increased when cultures were treated after virus had adsorbed to cells; since infection was not synchronized, most of the virus had probably already penetrated the plasma membrane by the time DEAE-D was added. Maximal enhancement occurred when DEAE-D was present in the inoculum. Enhancement of a lesser degree occurred when virus and DEAE-D were mixed, diluted, and inoculated onto cultures. Adsorption of LTV at 37 C as compared to that at 5 C usually yields about a threefold greater number of plaques after a 2-hr adsorption period. However, when DEAE-D was incorporated in the inoculum, greater enhancement occurred at 5 C than at 37 C, and the number of plaques produced at both adsorption temperatures was about equal. Results are compatible with the hypothesis that increased adsorption is a factor in enhancement of infectivity of LTV by DEAE-D.
Rapid Fluorescent-Antibody Stain Technique with Group A Streptococci
Authors: Freeburg Pat W.
Published: December 2020

A rapid fluorescent-antibody stain technique used with young broth cultures of trypsinized group A streptococci is described. Results from 1,214 trypsinized cultures of group A streptococci employing the rapid stain method were equivalent, both in specificity and sensitivity, when compared to results obtained from identical non-trypsinized cultures stained with the longer standard technique of Cherry, Goldman, and Carski. Moreover, the rapid method requires less than 2 min to complete.
Comparison of Cephalexin, Penicillin V, and Ampicillin in Streptococcal Infections in Monkeys
Authors: Saslaw Samuel , Carlisle Harold N.
Published: December 2020

Intravenous inoculation of a group A hemolytic streptococcus caused lethal infections in all of 11 untreated monkeys. Daily intragastric administration of either 25 or 50 mg per kg per day, given in two equal morning and afternoon doses, yielded similar results in monkeys treated with cephalexin, penicillin V, and ampicillin; all eight monkeys in each therapy group survived. At dose levels of 12.5 mg per kg per day, six of eight, four of eight, and one of eight receiving cephalexin, penicillin V, and ampicillin, respectively, died. The differences observed at the lower dose level between cephalexin and ampicillin could be attributed, in part, to differences in the minimal inhibitory concentrations (MIC) of cephalexin (MIC = 0.24 μg/ml) and ampicillin (MIC = 0.01 μg/ml). The differences in results between penicillin V, which had the same MIC as ampicillin, could perhaps be attributed, in part, to shorter duration of antibacterial activity and higher protein binding of penicillin V. These studies support previous observations that cephalexin at 25 to 50 mg/kg doses is effective in severe streptococcal sepsis in monkeys.
Quantitative Studies on Fabrics as Disseminators of Viruses
Authors: Sidwell Robert W. , Dixon Glen J. , Westbrook Louise , Forziati Florence H.
Published: December 2020

Cotton and woolen fabrics and fabrics of synthetic fibers were exposed by direct contact (pipette) and by aerosolization to poliovirus and to vaccinia virus in separate experiments, allowed to dry for 16 hr at 25 C in 35% relative humidity, and randomly tumbled with sterile swatches of the same fabrics for 30 min. By use of a HEp-2 cell assay system, up to 10
3.5
CCID
50
of poliovirus per ml and 10
4.4
CCID
50
of vaccinia virus per ml were recovered from the originally sterile fabrics as early as 1 to 10 min after contact. Maximum transfer of both viruses was achieved with wool blanket material, although high titers of vaccinia virus were recovered from all fabrics tested. Poliovirus placed on the fabrics in an aerosol tended to be transferred to the sterile fabrics at a greater rate than when it was placed on the fabrics by direct contact. The method of exposure had essentially no effect on the rate of transfer of vaccinia virus.
Volutin Granules in
Zoogloea ramigera
Authors: Roinestad Frank A. , Yall Irving
Published: December 2020

Zoogloea ramigera
, a gram-negative bacterium found in activated sludge, formed volutin granules when excess orthophosphate was added to a phosphate-starved culture. These volutin granules were stainable by hydrogen sulfide after lead acetate treatment and extractable by
N
-perchloric acid but were not adsorbed by activated charcoal. They appeared to consist of inorganic polyphosphate. Optimum granule formation in the arginine broth required 10 g of glucose, 3 mg of phosphate, and 1 to 20 mg of magnesium per liter of medium. At an Mg
2+
concentration of 1 mg/liter, very large granules appeared which often appeared to fill the cell. An excess of glucose, orthophosphate, or magnesium reduced granule formation. In the absence of sulfate, moderate granulation occurred in arginine broth before the addition of excess orthophosphate; granulation did not increase after the addition of phosphate.
Occurrence of Purple Sulfur Bacteria in a Sewage Treatment Lagoon
Authors: Holm H. W. , Vennes J. W.
Published: December 2020

The ecology of purple sulfur bacteria in a sewage oxidation lagoon was investigated. Chemical changes in the lagoon were investigated by monitoring biochemical oxygen demand (BOD
5
), sulfide, sulfate, phosphate, total carbohydrates, volatile acids, alkalinity, and
p
H. Lagoon water temperatures were observed daily. Microbial ecological relationships were deduced by enumerating coliforms, total bacteria other than anaerobes [Tryptone Glucose Extract (TGE) agar], methane formers such as
Methanobacterium formicicum
, sulfate reducers, purple sulfur bacteria, and algae. Finally, two strains of purple sulfur bacteria were characterized. Two populations, purple sulfur bacteria and total bacteria (TGE agar), reached maximal concentrations in the warmest part of the 1967 summer. Purple sulfur bacteria reached maximal numbers as concentrations of sulfide and volatile acids were depleted, whereas carbohydrates and alkalinity remained unchanged. Low sulfate levels, which were not limiting for sulfate reducers, may be attributable to storage of sulfur within purple sulfur bacteria. No biological, chemical, or physical agent was linked to the removal of coliforms. The increase of algae in the late summer of 1967 may have been related to the low organic content of the lagoon during this period. Although lagoon
p
H (7.7 to 8.2) was favorable for purple sulfur bacterial growth, temperatures and sulfides were not optimal in the lagoon for these organisms.
Chromatium vinosum
and
Thiocapsa floridana
(the predominant lagoon purple sulfur organism in 1967 and 1968) utilized certain carbohydrates, amino acids, volatile acids, and Krebs cycle intermediates. Also purple sulfur bacteria lowered BOD levels as demonstrated by the growth of
T. floridana
in sterilized sewage.
Application of Freeze-Etching Method to the Study of Reovirus-Infected LLC-MK
2
Cells
Authors: Rozee K. R. , Easterbrook K. B.
Published: December 2020

A continuous cell line of rhesus monkey kidney cells, LLC-MK
2
, was infected with reovirus type 1 (Lang). The cells were freeze-etched as a method for observing the structural details of the reovirus-induced cytoplasmic inclusion. Information on maturation may be obtained by preparing infected cells for electron microscopy by freeze-etching.
Detection and Incidence of
Escherichia coli
on Storage Pen Surfaces of Fishing Trawlers
Authors: Rosen A. , Levin R. E.
Published: December 2020

Six methods for the detection and enumeration of
Escherichia coli
on the storage pen surfaces of commercial fishing trawlers and in harbor wash water were evaluated.
E. coli
was found consistently present in Boston harbor water used for washing vessel holds and was detected either in small numbers or not at all on storage pen surfaces. Violet Red Bile Agar as a primary enumeration medium was found ineffective for detection of coliforms because of the nonselective development of large numbers of other gram-negative organisms. The use of
E. coli
broth at 44.5 C for primary most-probable-number determinations, followed by confirmation of
E. coli
on Levine Eosine Methylene Blue Agar, appears to offer numerous advantages over more conventional methods of detecting
E. coli
for survey studies of the fishing industry, where coliform-like organisms result in many false-positive presumptives with other methods.
Inhibition of
Bacillus megaterium
by a Trimethylamine Oxide-Associated Browning Reaction Product
Authors: Rosen B. , Christiansen L. N. , Busta F. F.
Published: December 2020

Heated combinations of trimethylamine oxide (TMAO) and culture media (tryptone, glucose, yeast extract broth or a defined minimal medium), or heated TMAO and glucose, contained substance(s) that inhibited growth of
Bacillus megaterium
. Inhibition was expressed primarily as an increase of the lag phase of growth; the logarithmic growth rate was comparable to control cultures. The addition of unheated TMAO to the culture media had no effect on growth. Results suggested that TMAO was decomposed during heating and that dimethylamine, one of the degradation products, reacted with glucose by a Maillard-Amadori reaction to produce the inhibitory substance(s).
Plaque Size Heterogeneity: a Genetic Trait of Lymphocytic Choriomeningitis Virus
Authors: Pulkkinen A. J. , Pfau C. J.
Published: December 2020

All of the ten strains of lymphocytic choriomeningitis virus assayed on BHK 21/13S cells showed various degrees of plaque size heterogeneity. The amount of virus released from these plaques was usually very small because of rapid photodynamic inactivation by neutral red. When virus from large and small plaques of a specific strain was plated, the same distribution of plaque size was obtained from each clone. Although it was shown that surface virus could possibly be randomly distributed at the time of addition of neutral red overlays, no virus could be isolated from nonplaque areas. Two different strains of virus (CA1371 and WE) with markedly different plaque size ranges were separated by plaque excision from plates infected with a mixture of both viruses.
Effect of Gas Hydrate Formers on Microorganisms
Authors: Prior B. A. , Fennema O. , Marth E. H.
Published: December 2020

Various bacteria, yeasts, and molds important to the food industry were incubated in aerosol cans containing A C Broth and one of the following three gas hydrate formers: propane, dichlorodifluoromethane (f-12), and 1,1-difluoro-1-chloroethane (f-142b). Most hydrate formers were tested at three concentrations: low (vapor state), intermediate (liquid state, low level), and high (liquid state, high level). Samples were continuously agitated for 48 hr at 21 ± 3 C. Changes in numbers of microorganisms were determined by plate count. With hydrate formers in the vapor state, propane was more toxic to the microorganisms tested than either f-12 or f-142b. The most resistant organisms from these trials were then tested against f-12 or f-142b in the liquid state. Hydrate formers were far more toxic in the liquid state than in the vapor state. With the exception of sporulated cultures of
Bacillus cereus
, all microorganisms tested were greatly reduced in numbers when agitated for 48 hr at 21 C in the presence of f-12 or f-142b.
Unusual Fermentative, Gram-Negative Bacilli Isolated from Clinical Specimens
Authors: Gilardi G. L. , Bottone E. , Birnbaum M.
Published: December 2020

Morphological and physiological characterization of 12
Aeromonas
strains isolated from clinical specimens demonstrated several important diagnostic features. These included polar arrangement of the flagella; production of oxidase, deoxyribonuclease, amylase, gelatinase, and lipase; lack of ornithine decarboxylase; and sensitivity to polymyxin. Awareness of these features should result in more frequent differentiation of aeromonads from the physiologically similar members of the genus
Plesiomonas
and the late- or non-lactose-fermenting species of
Enterobacteriaceae.
Allantoic Fluid as a Source of Arbovirus Hemagglutinin
Authors: Chung Y. S. , Spradbrow P. B.
Published: December 2020

Noninfectious hemagglutinins were prepared from the allantoic fluids of embryonated chicken eggs infected with Sindbis virus or with Murray Valley encephalitis virus.
Microbial Transformation of 19-Hydroxypregnanes
Authors: Singh Kartar , Marshall D. J. , Vézina C.
Published: December 2020

Nocardia
species aromatized 19-hydroxyprogesterone, 3β, 19-dihydroxy-pregn-5-en-20-one 3-acetate and pregn-5-ene-3β, 19, 20β-triol 3-acetate, without cleavage of the side chain, into 3-hydroxy-19-norpregna-1,3,5 (10)-trien-20-one.
Septomyxa affinis
aromatized the ring A and cleaved the side chain of 19-hydroxyprogesterone to yield estrone. With 19-hydroxypregna-4, 7-diene-3, 20-dione as substrate, the transformation was more complex and many products were formed.
Detection of Foot-and-Mouth Disease Virus Antibodies
Authors: Tokuda G. , Warrington R. E.
Published: December 2020

A passive hemagglutination test has been developed to detect and measure foot-and-mouth disease virus (FMDV) antibody by using glutaraldehyde as a coupling reagent. An optimal concentration of 10 to 40 μg of virus per ml with 0.25% glutaraldehyde at 25 C for 1 hr was established for the sensitization of sheep erythrocytes. A reaction time of 18 hr at 4 C or 2 hr at 37 C induced good agglutination in the presence of specific antibody. Sensitization was carried out in phosphate buffer, whereas agglutination and preadsorption of nonspecific agglutinins from sera were performed in gelatin (0.1%, w/v)-stabilized, phosphate-buffered saline. An optimal pH of 7.2 was also established for all reactions. Antibodies derived from guinea pigs hyperimmunized by infecting with FMDV, types A, O, and C were both virus-and type-specific. Preliminary experiments showed that strain A-119 and strain A-24 Cruzeiro could also be distinguished by hemagglutination. Parallel hemagglutination and complement-fixation tests showed the former to be two to four times more sensitive than the latter.
Antigenic Variation in Group A Streptococci: Types 11 and 9
Authors: Larsen Sandra A. , Moody Max D. , Facklam Richard R.
Published: December 2020

A strain of group A
Streptococcus
which was virulent but M-nontypable was isolated from patients in a hospital nursery during an epidemic. This strain, Boston 11, reacted in T-agglutination tests with antisera for types 9 and 11, an unusual combination. A comparison of this strain with Lancefield's M-11 strain (NCDC SS-721) and Alabama 11 (Provisional 61) revealed three serologically related but distinct strains. Antiserum produced with the Boston 11 strain exhibited similar reactivity with all three “11” strains as well as with M-9 (SS-501) as demonstrated in precipitin tests. Immunodiffusion studies indicated that the Boston 11 antigen was partially identical with the M-11 and M-9 strains and shared at least one antigen with the Alabama 11 strain. The Boston 11 antiserum could be made specific for precipitin tests, but bactericidal activity for the Alabama 11, M-11, and Boston 11 strains was essentially negative.
Detailed Methodology and Implementation of a Semiautomated Serial Dilution Microtechnique for Antimicrobial Susceptibility Testing
Authors: MacLowry James D. , Jaqua Mary J. , Selepak Sally T.
Published: December 2020

The detailed methodology and implementation of a semiautomatic microtechnique for performing serial dilution antimicrobial susceptibility studies are described. Quantitative susceptibility studies to a battery of antimicrobials are performed routinely on all significant clinical isolates. Results are reported as the minimal inhibitory concentration in micrograms per milliliter of broth. Guidelines relating standard doses of antimicrobials with expected blood and urine levels are presented to facilitate the use of the quantitative data. This microtechnique is used to measure serum and other body fluid levels of antimicrobial agents to document the level attained with a specific course of therapy. This technique is highly reproducible and has a high correlation with, and is at least 10 times faster than, standard glass tube techniques.
Deoxyribonuclease-Positive
Staphylococcus epidermidis
Strains
Authors: Zierdt Charles H. , Golde David W.
Published: December 2020

Use of the agar plate test for the enzyme deoxyribonucleate 3′-nucleotidohydrolase (deoxyribonuclease) can result in frequent misdiagnosis of
Staphylococcus epidermidis
as
S. aureus.
Simple Method of Evaluating Scrapie in Mice
Authors: Cochran Kenneth W. , Allen Lois B.
Published: December 2020

Mice in advanced scrapie characteristically clasp their hindlegs together. As the disease progresses into the clasping stage, mice exhibit a sequence of identifiable hindleg reactions which have categorized and assigned relative scores permitting objective, quantitative evaluation of disease.
Resistance of Weathered Cotton Cellulose to Cellulase Action
Authors: Kaplan Arthur M. , Mandels Mary , Pillion Elizabeth , Greenberger Marvin
Published: December 2020

Increased resistance of weathered cotton cellulose to microbial breakdown has been shown to be the result of development of resistance to the action of fungal cellulases. Photochemical activity during weathering exposure transforms the cellulose into an altered substrate that prevents access of the enzymes to susceptible sites of the cellulose molecule. It is postulated that the altered substrate consists of cellulose molecules of low degrees of polymerization, with some ring openings and altered chain ends. Weathered cellulose fails to adsorb cellulases.