bluuebunny/crossref_metadata_2025 huggingface dataset:
Rumen Microbial Ecology in Mule Deer
Authors: Pearson Henry A.
Published: December 2020

Mule deer rumen microbial populations from animals in the natural habitat in Utah and from captive deer fed various rations were studied. The microorganisms were characterized on the basis of morphology and Gram reaction. Rumen samples contained 13 identifiable types of bacteria and one genus of ciliate protozoa
(Entodinium).
Highest rumen bacterial populations were produced on rations containing barley. No differences in proportions of ruminal bacteria in the various morphological groups could be detected when animals were fed either natural browse plants or alfalfa hay. The total numbers of bacteria were similar for animals feeding on controlled diets of browse or hay and those in the natural habitat. Numbers of some bacterial types were directly related to ciliate protozoal numbers, whereas others were inversely related. Highest rumen ciliate protozoal populations were observed on rations containing barley. No differences in protozoal populations were noted between diets containing only browse or hay. Seasonal variations were noted in ciliate protozoal numbers from deer feeding in the natural habitat. The total number of ciliate protozoa decreased in the fall and winter and remained low until spring. There were indications that salt in the deer diet favorably affected rumen ciliate protozoa. Rather than revealing direct deer management applications, this study serves to stimulate and illuminate new approaches to research in range and wildlife nutrition.
Inactivation of the Bactericidal Activity of Human Serum by Liquoid (Sodium Polyanetholsulfonate
Authors: Lowrance Betty L. , Traub Walter H.
Published: December 2020

Four serum-sensitive strains of
Escherichia coli
were exposed to 10, 20, and 50% fresh, heat-inactivated, and fresh human serum to which had been added Liquoid at a final concentration of 0.05, 0.025, 0.0125 and 0.006%. It was found that 50% fresh serum (in nutrient, Mueller-Hinton, thioglycolate, or Trypticase Soy Broth) killed more than 10
4
organisms/ml within 3 min, whereas 20 and 10% fresh serum required up to 20 and 40 min, respectively, to kill a comparable number of organisms. To neutralize the activity of 50% fresh serum, 0.0125% Liquoid had to be added, whereas an 0.006% final concentration of Liquoid was sufficient to antagonize the activity of 10 and 20% serum. However, when exposing extremely small bacterial inocula to fresh serum, at least 0.025% Liquoid was necessary to abolish the serum-bactericidal activity of 20 and 50% fresh serum. Liquoid had to be added to 50% fresh serum within seconds to prevent the killing of the majority of test organisms derived from small inocula. It is recommended that blood samples drawn from septicemic or bacteremic patients be aseptically added to a suitable broth which contains at least 0.025% Liquoid in order to improve the chances of isolating pathogens present in small numbers.
Biochemical and Clinical Characteristics and Antibiotic Susceptibility of Atypical
Enterobacter cloacae
Authors: Washington John A. , Yu Pauline , Martin William J.
Published: December 2020

The characteristics of an atypical group of the family
Enterobacteriaceae
resembling
Enterobacter cloacae
were studied. The urinary tract was the most common source of these organisms, and most strains represented infections of secondary clinical significance. In contrast to typical
Enterobacter
strains, the atypical strains were highly susceptible to the cephalosporins; otherwise, there was a high degree of susceptibility to five other antibiotics and resistance to ampicillin except in very high concentration.
Growth and Pigmentation of
Epicoccum nigrum
in Submerged Culture
Authors: Tuttobello L. , Foppen F. H. , Carilli A.
Published: December 2020

Growth and pigmentation of
Epicoccum nigrum
was studied in submerged culture in various media. Red pigmentation of the mycelium and of fermentation broth was obtained only in a medium containing glucose and yeast autolysate. This pigmentation occurred at the time of maximal production of carotenoids. Observations on the submerged culture of this organism in flasks and in fermentors are described, and the details of a standardized procedure for the production of carotenoid pigments are given.
Combined Effects of Diphenyliodonium Chloride, Pine Oils, and Mustard Oil Soaps on Certain Microorganisms
Authors: Ahmed Zahir , Siddiqui Mahmood A. , Khan Ismat
Published: December 2020

Bactericidal and bacteriostatic activities of an emulsion containing 10.0% (v/v) terpineol, 0.5% (w/v) diphenyliodonium chloride, 11.0% (v/v) ethyl alcohol, and 5.62% saponified mustard oil were tested against a number of different types of organisms. The bactericidal concentration for
Salmonella typhosa
was 1:400. In the presence of 5.0% horse serum, it increased to 1:250. The bacteriostatic concentration varied from organism to organism;
Escherichia coli
and
Staphylococcus aureus
required 4,000 μg/ml for complete bacteriostasis, whereas
Corynebacterium diphtheriae, Salmonella paratyphi-A
, and
Shigella
required only 2,000 μg/ml for complete inhibition. A 4.0% concentration of the emulsion killed the spores of
Bacillus subtilis
within 6 hr.
In Vitro Studies with 5-Fluorocytosine
Authors: Shadomy Smith
Published: December 2020

5-Fluorocytosine, an antifungal agent with potential value as a chemotherapeutic agent, is being evaluated in the treatment of human cryptococcosis. In vitro studies with this agent have been hindered by the fact that it is inhibited significantly in the presence of partially degraded biological substances. This loss of activity is presumed to result from a competitive inhibition between the agent and its natural analogues. Procedures are described for in vitro studies with 5-fluorocytosine. These include methods for susceptibility testing and a bioassay for 5-fluorocytosine in biological fluids. Minimal inhibitory and minimal fungicidal concentrations of 5-fluorocytosine for
Cryptococcus neoformans
were usually in the range of 0.46 to 3.9 μg/ml and 3.9 to 15.6 μg/ml, respectively. Corresponding values for
Candida albicans
were 0.46 to 3.9 μg/ml and 15.6 μg/ml or greater, respectively. Strains of
C. neoformans
and
C. albicans
resistant to greater than 1,000 μg/ml were encountered both after exposure to the drug and in the absence of any known exposure. Bioassays of specimens from patients treated with 5-fluorocytosine indicated that serum and cerebrospinal fluid concentrations of 10 to 30 μg/ml and 8 to 20 μg/ml, respectively were readily achieved with a dosage of 100 mg per kg per day.
Incidence of Salmonellae in Meat and Meat Products
Authors: Weissman M. A. , Carpenter J. A.
Published: December 2020

Standard enrichment, plating, and biochemical techniques were used to assess the incidence of
Salmonella
species on beef and pork carcasses and processed meat products. The incidence of
Salmonella
in pork carcasses was 56% and in beef carcasses, 74%. These figures are about the same as previously reported for pork but much higher than previously reported for beef carcasses; however, they represent only three to five abattoirs in Georgia and do not necessarily represent contamination levels throughout the country. Examination of carcasses by area did not indicate greater incidence of
Salmonella
in any one area. Two areas suggested for representative sampling are the cervical and anal areas of the carcass. Of the sausage samples examined, 38% of the fresh pork sausage, 9% of the smoked pork sausage, and 1 sample (souse) of 16 samples of miscellaneous sausage products were contaminated. Examination of subsamples indicated that
Salmonella,
when present in sausage products, could be found in any section of the entire sample.
Effect of Meat and Isolated Meat Proteins on the Thermal Inactivation of Staphylococcal Enterotoxin B
Authors: Satterlee L. D. , Kraft A. A.
Published: December 2020

The thermal inactivation of staphylococcal enterotoxin B was studied in a phosphate-saline buffer, in the presence of two meat proteins, myosin and metmyoglobin (MetMb), and in a ground-beef slurry. When enterotoxin B was incubated at temperatures from 60 to 110 C, it was shown that the initial thermal inactivation at 80 C was faster than at 100 or 110C. The heating of enterotoxin B at 60, 80, and 100 C in the presence of either myosin or MetMb resulted in a rapid loss of the enterotoxin. Thermal loss of the enterotoxin B molecule in the presence of meat proteins was more pronounced at 80 C than at either 60 or 100 C. Thermal loss of enterotoxin B molecule in the presence of meat proteins was more pronounced at 80 C than at either 60 or 100 C. Thermal loss of enterotoxin B in a ground round slurry was rapid when compared to inactivation in a phosphate-saline buffer. The rapid loss of enterotoxin B in the slurry may be due to a combination of thermal inactivation and the binding of enterotoxin molecules to meat proteins.
T Antigens of Bovine and Canine Adenoviruses Demonstrated by Immunofluorescence
Authors: Kern Jerome , Gilden Raymond V. , Huebner Robert J.
Published: December 2020

The intracellular development in acutely infected cells of bovine and canine adenovirus T antigens was followed by immunofluorescent staining. With both species of adenovirus, antigen was first detected as intranuclear pin-points at 18 hr postinfection and coalescence into large lobular masses was noticed by 24 hr. Cross-reactions between bovine 1 (nononcogenic) and bovine 3 (oncogenic) T antigens were not observed by the direct technique although the more sensitive indirect procedure did reveal cross-reactivity. Extensive cross-reactions were observed between the T antigens of the oncogenic canine hepatitis virus and the ”nononcogenic” Toronto strain of canine adenovirus. The magnitude of these reactions places the two canine strains in the same T antigen subgroup. The canine and bovine T antigens were not stained by tumor antisera against any of the known human or simian T antigen subgroups. Antigen synthesis was not prevented by inhibitors of deoxyribonucleic acid synthesis although the appearance was altered markedly.
Two Additional
Salmonella
Serotypes:
Salmonella enteritidis
Ser 58:a:- and
Salmonella enteritidis
Ser 44
Z
36
,
Z
38
:-
Authors: Ball Mary M. , Martin William J. , Wood Ronald M. , Powers Catherine E.
Published: December 2020

The antigenic compositions of two additional
Salmonella
serotypes isolated from the feces of man were determined to be 58:a:— and 44:
Z
36
,
Z
38
—.
Prodigiosin-like Pigments from
Actinomadura (Nocardia) pelletieri and Actinomadura madurae
Authors: Gerber Nancy N.
Published: December 2020

Thirteen red strains of
Actinomadura (Nocardia) pelletieri
and three of
A. madurae
were shown to produce prodigiosin-like pigments. Both of the two major pigments which were observed on thin-layer chromatograms had

R
F

values significantly greater than prodigiosin. The main pigment from
A. madurae
953 was shown by mass and nuclear magnetic resonance spectroscopies to be nonylprodigiosin. The major pigment from
A. pellitieri
had a C
11
H
22
side chain in a ring form, but it was distinctly different from metacycloprodigiosin. “Prodiginine” was proposed as a name for the invariant aromatic portion of the prodigiosin structure.
Lipase from
Pseudomonas fragi
. I. Purification of the Enzyme
Authors: Lu J. Y. , Liska B. J.
Published: December 2020

The experimental conditions required to isolate a lipase from
Pseudomonas fragi
were determined. The organism was grown in a buffered tryptone medium for 4 to 5 days at 20 C. The lipase in the culture supernatant fluid was isolated by fractionation with ammonium sulfate at 60% saturation, followed by acetone precipitation at 30-60% concentration. Further purification was made by using Sephadex G-200 gel-filtration and diethylaminoethyl cellulose chromatography. Electrophoretic analysis of the purified lipolytic fraction showed apparent homogeneity by both cellulose polyacetate and disc electrophoresis. The specific activity of the purified enzyme was about 100 times that of the starting culture filtrate, and the yield was about 1.8% of the original activity.
Predominant Catalase-negative Soil Bacteria. II. Occurrence and Characterization of
Actinomyces humiferus
, sp. N
Authors: Gledhill William E. , Casida L. E.
Published: December 2020

A microorganism resembling an
Actinomyces
species was found to be a numerically predominant inhabitant of various organically rich soils. This organism forms a hyphal-like structure with true branching that fragments into gram-positive diphtheroid and coccoid elements. Its cells ferment carbohydrates and contain both lysine and ornithine as the major basic amino acids of the cell wall. It is catalase-negative, microaerophilic to aerobic, and sensitive to lysozyme, and it is dependent on an organic nitrogen source and incubation at 30 C for optimum growth. Based on these characteristics, a new species,
Actinomyces humiferus
, is proposed. The ecological and medical implications of a large soil population of this microorganism are discussed.
Effect of
p
H on the Preservation of Palm Wine by Sulfite
Authors: Faparusi S. I.
Published: December 2020

A study of the effect of
p
H on the preservation of palm wine by sulfite was made. It was concluded that at
p
H 4.0 to 5.0, when the palm wine is considered most suitable for drinking, the concentration of the sulfite required to suppress microfloral activities would be excessive for human consumption.
Method for Increasing Atmospheric Carbon Dioxide in Bacteriological Incubators
Authors: Karslon Alfred G. , Caskey Patrick E.
Published: December 2020

We have adapted three incubators for culturing mycobacteria in an atmosphere of approximately 5% CO
2
and two incubators for culturing other organisms in atmospheres of approximately 10% CO
2
.
Development of Radiation Resistance in
Salmonella
Cultures
Authors: Licciardello J. J. , Nickerson J. T. R. , Goldblith S. A. , Shannon C. A. , Bishop W. W.
Published: December 2020

Cultures of
Salmonella
subjected to repeated cycles of gamma-irradiation and subculture developed radiation resistance sooner at a low cycling dose (∼1% survival) compared to a high cycling dose (∼0.001% survival). Radioresistant cells in a population of radiosensitive cells of
Salmonella newport
or
S. typhimurium
could be selected by the double-irradiation plate method. The frequency of radioresistant cells in a population of
S. newport
was found to be about 1 per 8.9 million. Radio-resistant cells obtained by cyclic irradiation and subculture were larger (plumper) than the parent strain and showed a marked pleomorphism.
Mode of Action of Lomofungin
Authors: Gottlieb David , Nicolas Gregorio
Published: December 2020

Lomofungin inhibited the growth of some yeasts and mycelial fungi at concentrations between 5 and 10 μg/ml. At such concentrations, there was no decrease in endogenous and exogenous oxygen consumption, and even 50 μg of antibiotic per ml caused only slight decreases. The permeation of the cell membrane was changed so that leakage of ninhydrin-positive substances was reduced, and the uptake of
14
C
-labeled glucose, amino acids, uracil, and thymidine was decreased at concentrations as low as 4 μg/ml. Protein synthesis in whole cells of
Saccharomyces cerevisiae
was reduced 35% at 10 μg/ml. However, the antibiotic did not reduce the incorporation of phenylalanine-
U
-
14
C
into polypeptides with cell-free systems of
Rhizoctonia solani
and
S. cerevisiae
. The synthesis of ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) was inhibited even at concentrations of lomofungin of 4 μg/ml. Since RNA synthesis was inhibited at lower concentrations and earlier than DNA synthesis, the primary site of action of the antibiotic appears to be the synthesis of RNA.
Quantitative Urine Culture by Surface Drop Method
Authors: Lorrier Johanna C. , Valkenburg Hans A.
Published: December 2020

A simple drop method for quantitative urine culture was developed and tested in comparison with standard methods for bacterial urinary counts. In a group of 452 urines all yielding
Escherichia coli
, 74 showed counts of more than 100,000 colonies, and 16 showed counts between 10,000 and 100,000 colonies per ml. Of these 90 urines, 3 of the 16 in the doubtful group were false negative with the drop method. Another 7 urines in the total number of 452 showed discrepancies, but, because all would have been repeated, the second urine sample would have corrected the primary result. The ease and cleanliness of the method render it a suitable technique for screening normal and patient populations. The method was applied on a population sample of 1,330 persons from whom unwashed mid-stream urine was collected and yielded figures comparable with results published in the literature. The method discriminates between steps of 10-fold difference, whereas more accurate count methods show a standard error of ±25% and are reliable in a double dilution series.
Fluorescent-Antibody Studies with Antisera Against Heated and Unheated Poliovirus Type 1
Authors: Hatch Milford H.
Published: December 2020

Fluorescent-antibody (FA) reagents were prepared from sera of guinea pigs immunized with either native infectious poliovirus type 1 or poliovirus type 1 which had been heated at 56 C for 30 min. Conjugates made from sera of animals immunized with heated virus gave higher direct FA staining titers on air-dried, acetone-fixed, infected cells than conjugates made from sera of animals immunized with native infectious virus. Evidence was obtained that complement-fixing antibody reactive with heated antigen was responsible for the FA staining. Two conjugates prepared from sera of guinea pigs immunized with heated poliovirus type 1 were successfully used to identify 21 type 1 viruses isolated from a group of 44 stool suspensions studied as unknowns. These conjugates did not stain any of 23 heterologous enteroviruses present in the remainder of the stools and gave minimal non-specific staining.
Nutritional Value of Lipids in
Hydrogenomonas eutropha
as Measured in the Rat
Authors: Waslien Carol I. , Calloway Doris Howes
Published: December 2020

Hydrogenomonas eutropha
is known to accumulate lipid, comprised largely of polymerized β-hydroxybutyric acid, when maintained in nitrogen-deficient medium. This lipid was very poorly absorbed by mice from bacteria-containing diets, even though nitrogen absorption was adequate. The monomer, free β-hydroxybutyric acid, was well absorbed from purified diet. Rats fed the monomer or butyric acid ate less food and grew more slowly than rats fed corn oil.
Klebsiella, Enterobacter
, and
Serratia
: Biochemical Differentiation and Susceptibility to Ampicillin and Three Cephalosporin Derivatives
Authors: Zabransky Ronald J. , Hall Jack W. , Day Fred E. , Needham Gerald M.
Published: December 2020

Three hundred twenty-nine strains of the tribe
Klebsielleae
were compared by several biochemical tests and by susceptibility to selected antibiotics. Biochemical tests included urease, amino acid decarboxylase, and hydrogen sulfide production; fermentation of lactose and dextrose; motility; and tests in the IMViC (indole, methyl red, Voges-Proskauer, citrate) series. The isolates were:
Klebsiella
species, 67.5%;
Enterobacter
species, 28%, and
Serratia
species, 4.5%. Minimal inhibitory concentrations of cephaloridine, cephalothin, and a new cephalosporin, cephalexin, and of ampicillin were determined by the agar dilution procedure. Cephalosporins at 20 μg/ml or less inhibited 90% of the
Klebsiella
strains but only 15% of the
Enterobacter
strains. Ampicillin inhibited 27% of
Enterobacter
strains and 17% of
Klebsiella
strains.
Serratia
isolates were insensitive to the cephalosporins and ampicillin. The results suggest that precise identification of this group to the generic level can be accomplished readily in the clinical laboratory and that such information is helpful in the preliminary selection of an antibiotic for treatment of clinical infections.
Persistence of
Salmonella typhimurium
on Fabrics
Authors: Wilkoff Lee J. , Westbrook Louise , Dixon Glen J.
Published: December 2020

The persistence of
Salmonella typhimurium
(V-31) on wool blanket, wool gabardine, cotton sheeting, cotton knit jersey, cotton terry cloth, and cotton wash-and-wear fabrics was studied. Three methods of exposure were employed to contaminate the fabrics: direct contact, aerosol, and a lyophilized mixture of bacteria and dust having a high content of textile fibers. After contamination, the fabrics were held in 35 or 78% relative humidity at 25 C. The persistence time of
S. typhimurium
on fabrics held in 35% relative humidity was substantially longer when the fabrics were contaminated by direct contact or by exposure to dust containing bacteria than when contaminated by exposure to aerosolized cultures. Viable bacterial populations persisted for 24 weeks at relatively high population densities on swatches of wool gabardine, cotton sheeting, cotton knit jersey, and cotton terry cloth exposed by direct contact and held in a humidity of 35%. In 78% humidity, bacterial populations persisted on the fabrics for relatively shorter periods of time regardless of the mode of contamination or fabric type. This organism retained its virulence for Swiss mice after being recovered from wool gabardine swatches held 8 weeks in humidities of 35 or 78% and from cotton terry cloth swatches held 6 weeks in the same humidities.
Preparation of Primary Bovine Corneal Epithelial Cell Cultures for Use in Virological Investigations
Authors: Wilcox G. E.
Published: December 2020

Primary and secondary cell cultures in sufficient quantity for use in virological investigations were prepared and were found suitable for growth of animal viruses.
Substrate Specificity of
Actinoplanes
Antibiotic Peptide Lactonases
Authors: Perlman D. , Hou C. T.
Published: December 2020

A constitutive peptide lactonase from
Actinoplanes missouriensis
hydrolyzed echinomycin, stendomycin, thiostrepton, vernamycin B, staphylomycin S, and etamycin. An induced lactonase hydrolyzed actinomycin but not the other peptide lactones.
Rapid Technique for Enumeration and Isolation of Peroxidase-producing Microorganisms
Authors: Bordeleau Lucien M. , Bartha Richard
Published: December 2020

Peroxidase-positive microorganisms were enumerated on agar plates by use of a
p
-anisidine-H
2
O
2
spray. Combined with replica-plating, the same technique allowed the selective isolation of peroxidase-producing microbial cultures.
Immunological Studies with an M-Deficient Histoplasmin Skin-Test Antigen
Authors: Kaufman Leo , Mclaughlin David , Terry Robert T.
Published: December 2020

Previous studies have shown that a single skin test to histoplasmin may induce complement-fixing antibodies or M precipitins (or both) to histoplasmin in histoplasmin-sensitive, but serologically negative, individuals. Ideally a skin-test antigen should be one which detects hypersensitivity without stimulating humoral antibodies. Histoplasmin skin-test antigens presently used contain both H and M antigens. The present study was undertaken to evaluate an histoplasmin skin-test antigen deficient in the M component but containing the H antigen. Thirty histoplasmin-hypersensitive subjects were bled prior to administration of the experimental skin-test antigen and at various time intervals thereafter. Only six of the thirty hypersensitive subjects showed serological responses. The sera of the six, however, only showed weak precipitin reactions, five showed M bands, and only one showed an M and an H band. None showed complement-fixation titers with either the yeast or mycelial antigens of
Histoplasma capsulatum.
Our data suggest that the use of a skin-test antigen purified to contain only H component would detect histoplasmin hypersensitivity without inducing antibodies and would eliminate false-positive serological reactions caused by the M component.
Some Factors Affecting Fermentation Capacity and Net Growth of Rumen Microorganisms
Authors: El-Din Manal Zaki , El-Shazly K.
Published: December 2020

The fermentation rate of rumen microorganisms obtained from a sheep fed on hay was determined at different hours after feeding. The highest rate of fermentation was obtained immediately after feeding whereas the lowest rate was always before feeding. The effect of adding glucose, sucrose, and starch alone or in combination with urea, sodium citrate, or succinic acid on the maximal fermentation rate was studied. In no case was the maximal fermentation rate greater than that obtained in the presence of concentrate and straw. An investigation on the effect of C/N ratios, dilution, and substrate concentration on the net growth of rumen microorganisms was undertaken. The highest net growth value was obtained with a C/N ratio of 16.5 to 17.5, which is the ratio found for the ration fed to the animal. It was possible to increase net growth approximately threefold by using the proper dilution and fivefold by using the proper feed concentration.
Large-Plate Method for the Assay of Neomycin in Serum
Authors: Van Soestbergen A. A.
Published: December 2020

A large-plate method employing radial diffusion from small paper discs for assaying serum levels of neomycin is described. More than 120 discs placed on a loading plate and loaded with 20 μliters of sample could all be brought into contact with the agar plate at one time. The requirement for elaborate statistical design to compensate for time-dependent bias was thus eliminated. The dose-response curve was linear for a range of at least 0.5 to 2.5 μg/ml. The experimental limits for the actual zone width (distance from the edge of the paper disc to the outer edge of the inhibition zone) for 120 repetitions of the assay of neomycin in one and the same serum, carried out simultaneously on one large plate, were about ± 6% (95% confidence interval). The 95% confidence interval for the distribution of difference between duplicate zones obtained for the assay of neomycin in 34 different sera, also carried out on one plate, was about ± 10%. The dose-response lines for a standard and for three unknown sera, when carried out together on one plate, were parallel within the variability (±
SD
one) of the zone width. The large-plate method is considered to be more efficient than the use of the smaller petri dishes. The method is suitable for the assay of penicillin in serum and can most probably be used for the assay of a wide variety of substances for which radial diffusion from paper discs into agar is feasible.
Differential Responses of Single Cells and Aggregates of Mycoplasmas to Ultraviolet Irradiation
Authors: Furness Geoffrey
Published: December 2020

Except for
Mycoplasma fermentans
strain PG 18, single-cell suspensions of
M. arthritidis, M. fermentans
(ATCC 19989),
M. hominis
type 1,
M. orale
types 1 and 2,
M. pneumoniae,
and
M. salivarium
were inactivated exponentially by ultraviolet (UV) irradiation, in contrast to broth cultures containing clusters of elementary bodies. The susceptibility of the mycoplasmas was unaffected by storage at 2-4 C and at -70 C, by sonication, and by filtration. The rate of inactivation was dependent on the intensity of the radiations but independent of the concentration of the cells. Therefore, single-cell suspensions of these mycoplasmas could be differentiated from aggregates of cells by exponential inactivation of the colony-forming units (CFU). By this criterion, the CFU of
M. arthritidis
in the exponential phase of growth consisted of single cells, in contrast to the other species in which the CFU contained two or more elementary bodies. Even though the cultures of
M. fermentans
(PG 18) were grown from single cells, they were not homogeneous in their susceptibility to UV light. Neither were cultures of
M. arthritidis
and
M. orale
type 1 grown from single cells which had survived irradiation.
Microbiological Study of Water-Softener Resins
Authors: Stamm John M. , Engelhard Warren E. , Parsons James E.
Published: December 2020

Microbial identification using effluents backflushed from exhausted urban and rural tank resins and cleaned resins containing the sulfonated copolymer of styrene and divinylbenzene (SDB) were completed, along with microbial assessment of the concentrated stock salt brine. Forty-four different bacterial and fungal genera were identified. Extensive biochemical and animal virulence tests completed on one of the six bacterial salt brine isolates indicated a pathogenic staphylococcal strain. The retention of
Staphylococcus aureus, a Flavobacterium sp,
and
Escherichia coli
B bacteriophage was demonstrated both by using the nonexhausted sodium-regenerated resin and by using the same resin exchanged with different mono-, di-, and trivalent cations. Effluent counts completed after bacterial seepage through the resins indicated the Pb
++
exchanged resin removed 55% of the bacteria; Na
+
, Fe
++
, and Al
+++
removed 31 to 36% and Ca
++
and Cu
++
removed about 10 to 15%. Seventy per cent or more of the bacteriophage was removed by Fe
++
, Cu
++
, and Al
+++
, whereas the Ca
++
and Na
++
cations removed 25 to 31%. Over a 77-day period, nonsterile tap water was passed through bacterial seeded and uninoculated SDB (Na) resin columns. Effluent and resin elution counts demonstrated the growth and survival of 2 different bacteria per column. Increased bacterial retention, survival, and multiplication occurred concomitantly with accumulation of organic and inorganic materials and the Ca
++
and Mg
++
cations from the tap water. Furthermore, microbial elution from resin particles taken from column depths of 1, 8, and 16 cm indicated a bacterial diminution with increasing depths.
In Vitro Action of Carbenicillin Against Bacteria Isolated from Clinical Material
Authors: Isenberg Henry D. , Siegel Marie
Published: December 2020

More than 500 bacteria isolated from patient material were tested against carbenicillin (disodium α-carboxybenzylpenicillin) by diffusion and dilution modalities. The same bacteria, which included
Pseudomonas aeruginosa, Escherichia coli, Klebsiella-Aerobacter-Enterobacter
group, various species of
Proteus, Staphylococcus aureus
and
epiddermidis,
enterococci, pneumococci,
Streptococcus pyogenes,
etc., were examined for susceptibility to other antibiotics commonly used with special emphasis on ampicillin and cephalothin. The responses of pyocine-typed
P. aeruginosa
were the most remarkable. The majority of these bacteria displayed susceptibility to carbenicillin by both the dilution and the diffusion techniques. The concentrations of this antibiotic used in the laboratory were of the same order of magnitude as that of the other drugs. The laboratory behavior of the other bacteria, toward this new semisynthetic penicillin derivative approximated their response to ampicillin and cephalothin.
Modified Two-Phase System for Partition of
Bacillus macerans
Spores
Authors: Sacks L. E.
Published: December 2020

An aqueous two-phase system made with polyethylene glycol (PEG) 1000 and potassium phosphate gives much higher recovery of
Bacillus macerans
spores in the upper phase (PEG rich) than does a similar system utilizing PEG 4000. The upper phase completely rejects vegetative cells, which collect at the interface. The system may be useful in purifying spores of other species. Scanning electron micrographs of
B. macerans
spores cleaned in this system show no obvious attached sporangial fragments. The micrographs show that the ridged coat may form polygonal structures at the poles, as previously observed in
Bacillus polymyxa
spores.

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Actinomyces naeslundii
as an Agent of Human Actinomycosis
Authors: Coleman R. Marie , Georg Lucille K. , Rozzell Allen R.
Published: December 2020

The repeated isolation of
Actinomyces naeslundii
from clinical materials associated with disease led to a comparison of isolates from the normal mouth with isolates from pathological clinical materials not from the mouth area. No important differences were observed between the isolates from these two sources. A human case of empyema of the gall bladder, apparently due to
A. naeslundii,
is described.

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Comparative Study of the Efficacy of Seven Paper-Reagent Strips and Conventional Biochemical Tests in Identifying Gram-negative Organisms
Authors: Matsen John M. , Sherris John C.
Published: December 2020

Gram-nagative organisms were tested with commercially available reagentimpregnated strips (PATHO-TEC). Of the 291 strains, all were tested by using seven paper tests and their conventional counterparts. Excellent correlation was obtained with the oxidase, phenylalanine-deaminase, and Voges-Proskauer tests. Indole tests made on liquid medium cultures also gave complete correlation, but some false-negative results with indole-positive
Proteus
strains were obtained when growth from solid medium was tested by the strip method. Paper strip urease tests were positive within 2 hr with all
Klebsiella
and some
Serratia, Herellea
, and
Citrobacter
strains as well as with
Proteus
strains. Approximately 15% of citrate strip test results differed from those of the conventional tests, and reproducibility was poor on retest. The lysine decarboxylase strip test showed a number of discrepancies and posed problems of interpretation and readability. Paper reagent strip methods are simple and convenient and merit further development to increase the specificity of those which depend on
p
H change up to that achieved with the Voges-Proskauer, oxidase, phenylalanine, and indole methods.
Rapid Diagnosis of Bacteremia
Authors: Finegold Sydney M. , White Maurice L. , Ziment Irwin , Winn William R.
Published: December 2020

Early appropriate treatment of bacteremia is important in minimizing morbidity and mortality. Standard blood culture methods are not optimal since several days are often required for recovery and identification of organisms which may be present in the blood. The use of a membrane filter technique allows one to grow any organisms present in blood much more rapidly than by broth or pour plate culture. Furthermore, growth is in the form of typical colonies on the surface of solid media, and a series of rapid diagnostic tests may be used to provide speedy identification. Use of membrane filters also facilitates removal by washing of normal antibacterial factors and antimicrobial drugs which may be present in blood. Although the filter technique yielded the most rapid growth, broth culture and whole blood pour plates yielded more positive cultures and use of all three systems was necessary for maximal recovery of organisms in blood cultures. Data on quantitative aspects of bacteremia in the antimicrobial era are also presented. The number of low level bacteremias (10 colonies/ml or less) is surprisingly high. This is particularly true for gram-negative bacilli; antimicrobial therapy at the time of culture undoubtedly influenced these results greatly. Finally, suggestions are given for a much simpler and more efficient membrance filter blood culture technique.

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In Vitro Effects of Carbenicillin Combined with Gentamicin or Polymyxin B Against
Pseudomonas aeruginosa
Authors: Eickhoff Theodore C.
Published: December 2020

Disodium carbenicillin and gentamicin sulfate have both shown promise in the treatment of infections caused by
Pseudomonas aeruginosa
. This study was designed to explore possible synergistic relationships among the new as well as the established antimicrobial agents used to treat such infections. With an agar dilution technique, minimum inhibitory concentrations of 27 strains of
P. aeruginosa
were determined in two-dimensional tests. Graphs of equal biological activity (isobolograms) demonstrated moderate synergistic effects of the carbenicillin-gentamicin combination over therapeutically feasible concentration ranges. In contrast, the combination of carbenicillin and polymyxin B showed only additive or slightly antagonistic effects. Tests of bacterial killing confirmed the presence of carbenicillin-gentamicin synergy in 3 of 6 strains of
P. aeruginosa
, but did not show true antagonism between carbenicillin and polymyxin B. Clinical trials of both drug combinations are advisable to determine whether therapeutic results can be improved, and whether the dosages of gentamicin or polymyxin B can thereby be reduced to lessen their toxic hazards.
Nitrate Ion-Selective Electrode in Microbial Media
Authors: Manahan Stanley E.
Published: December 2020

A nitrate ion-selective electrode has been used to follow the kinetics of the reduction of nitrate by a bacillus isolated from the rumen of a sheep. The electrode system and the microbial culture were found to be quite compatible, although the formation of nitrite limits the utility and precision of the measurement. The formation of nitrite was followed simultaneously by a colorimetric method. Nitrate was converted quantitatively to nitrite. The rate of the reaction was found to increase to a plateau value, then drop abruptly when the nitrate was exhausted.
Effect of Endotoxin on Serum Zinc Concentrations in the Rat
Authors: Pekarek Robert S. , Beisel William R.
Published: December 2020

Serum zinc concentrations decreased significantly in a dose-dependent response after endotoxin administration in the rat. The reproducibility and sensitivity of the biological response offer a potential bioassay of endotoxin.
Scanning Electron and Phase-Contrast Microscopy of Bacterial Spores
Authors: Bulla L. A. , Julian G. St. , Rhodes R. A. , Hesseltine C. W.
Published: December 2020

The three-dimensional immages of free and intrasporangial spores produced by scanning electron microscopy show surface structures not visible by phase-contrast microscopy. Although fine surface detail is not elucidated by scanning electron microscopy, this technique does afford a definitive picture of the general shape of spores. Spores of
Bacillus popilliae, B. lentimorbus, B. thuringiensis, B. alvei, B. cereus,
and
Sarcina ureae
have varying patterns of surface ridge formation, whereas spores of
B. larvae, B. subtilis,
and
B. licheniformis
have relatively smooth surfaces.

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Use of Mitomycin C to Distinguish
Brucella abortus
Field Strains from the Vaccinal
Brucella abortus
Strain 19
Authors: Myers Donald M. , Dobosch Dora
Published: December 2020

Field strains of
Brucella abortus
were resistant to mitomycin C, whereas strain 19 was sensitive; therefore, the antibiotic was used to distinguish
B. abortus
strain 19 from other strains.

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Prolongation of Microbiological Air Sampling by a Monolayer on Agar Gel
Authors: May K. R.
Published: December 2020

The useful life of agar in aerosol samplers is greatly extended by treatment with a dilute emulsion of oxyethylene docosanol. Growth of viable organisms is unaffected.
Production of
m
-Cresol by
Valsa friesii
Authors: Child J. J. , Nesbitt L. R. , Haskins R. H.
Published: December 2020

m
-Cresol has been isolated from culture filtrates of
Valsa friesii.
The yield after 10 days of growth on glucose-phytone broth was 160 mg/liter.
Effects of Light, Temperature, and
p
H Value on Aflatoxin Production In Vitro
Authors: Joffe A. Z. , Lisker N.
Published: December 2020

In the complete absence of light, an isolate of
Aspergillus flavus
produced up to 170,000 pg aflatoxin per g, whereas the incubation of the fungus in light caused a reduction (35,000 pg/g) of the toxin synthesis.
Sugars and Amino Acids as Carbon, Nitrogen, or Energy Sources for
Coccidioides immitis
Spherules and Endospores
Authors: Sippel John E. , Levine H. B.
Published: December 2020

Of various carbohydrates and amino acids tested, glucose, mannose, fructose, and glutamate were the most efficient substrates metabolized by the endospores and spherules of
Coccidioides immitis
.
Use of Sealed Agar Plates for Bacterial Cultures Under Jungle Conditions
Authors: Moellering Robert C. , Kunz Lawrence J.
Published: December 2020

Commercially available sealed blood-agar plates have been demonstrated to retain their usefulness for as long as 3 months under jungle conditions without refrigeration.
Combined Screw-Cap and Rubber-Stopper Closure for Hungate Tubes (Pre-reduced Anaerobically Sterilized Roll Tubes and Liquid Media)
Authors: Attebery H. R. , Finegold S. M.
Published: December 2020

A double-closured method introduced for Hungate tubes eliminates clamps or special racks to hold the rubber stoppers in place while the tubes are being processed. The system prevents stoppers from being dislodged by gas-producing anaerobes and keeps the stoppers sterile so that the closed system of transfer can be conveniently utilized. Open and closed systems for handling a gas-producing anaerobe were compared. Ten tubes containing
Clostridium perfringens
were opened; the organism was detected in the air by use of an impingement collector. The gloved hand of the operator also revealed the test organism. A similar trial with culture material removed by the closed system (syringe transfer) resulted in no detectable contamination of the environment.
Mouse Toxicity of Fungi of Tobacco
Authors: Hamilton P. B. , Lucas G. B. , Welty R. E.
Published: December 2020

A bioassay for fungal toxins based on the intraperitoneal injection of test materials into mice was used to screen 976 cultures isolated from tobacco and grown in a high-protein baby cereal and also to determine whether samples of tobacco damaged by fungi are more toxic than samples of apparently sound tobacco. Of 236 fungal isolates from noncured tobacco, 79% were lethal when homogenized cultures of these isolates were tested. Forty-nine per cent of 740 fungi isolated from cured tobacco were lethal. Of the genera from which 30 or more isolates were tested,
Epicoccum, Alternaria
, and
Penicillium
had the highest percentage of toxic isolates from non-cured tobacco, whereas
Epicoccum, Aspergillus
, and
Alternaria
had the highest percentage from cured tobacco. Samples of tobacco naturally infected with brown spot, caused by
Alternaria tenuis
, did not have a significantly different LD
50
value after 48 hr than comparable disease-free samples. However, animals which died from doses near the LD
50
dose of tobacco infected with
Alternaria
generally died in 24 to 48 hr with signs associated with a depressant rather than a stimulant, such as nicotine, which caused death in 15 to 30 min. These signs were duplicated by injecting homogenized pure cultures of
Alternaria
. These studies, although inconclusive with regard to the effects of fungal contaminants on the quality or usability of tobacco, have developed evidence that suggests the advisability of a study on smoke or smoke condensates from moldy and nonmoldy tobacco.
Role of Interferon in the Propagation of MM Virus in L Cells
Authors: Giron David J.
Published: December 2020

MM virus propagated in mouse brain replicates to low titers in L cells without production of cytopathic effect (CPE). After growing the virus in BHK-21 cells, however, the virus replicates to high titers in L cells with complete CPE. It was found that suspensions of MM virus propagated in L cells directly from the mouse brain contained much more interferon than did suspensions of virus which had first been grown in BHK-21 cells. Mouse brain suspensions of the virus were also found to contain high interferon titers. Treatment of L cells with actinomycin D before infection with mouse brain-grown virus resulted in full virus replication with CPE. BHK-21 cell-grown virus diluted in L cell interferon behaved like mouse brain-grown virus in L cells. It is concluded that the presence of interferon in the inoculum is largely responsible for the suppression of MM virus replication in L cells.
Evaluation of Culture Media for the Isolation of Salmonellae from Feces
Authors: Sharma R. M. , Packer R. A.
Published: December 2020

A study conducted on 300 fecal samples from a cow and a pig, each artificially contaminated with approximately four
Salmonella
organisms revealed that, of the three enrichment broths used in conjunction with the three selective media, the maximum number of isolations were obtained with Brilliant Green MacConkey broth (BGMB), followed by those obtained with tetrathionate (TTB), and the least with selenite broth. The combination of BGMB with Brilliant Green-neutral red-lactose agar (BGNRLA), and TTB with desoxycholate citrate agar (DCA) gave an equal number of isolations. Of the three selective media used in conjunction with the three enrichment broths, the maximum number of recoveries were obtained on BGNRLA, followed by those on DCA, and least number of isolations on bismuth sulfite agar (BSA). The combination of selenite F broth-BSA appeared to be somewhat inhibitory for the growth of
Salmonella
organisms. Of the two selective media combinations, the DCA-BGNRLA combination yielded the highest number of isolations. The use of all three selective media gave still better results. Selenite and tetrathionate broths were found unsuitable for isolating
Salmonella choleraesuis
from feces. BGMB, containing 100 μg of Brilliant Green per ml, proved to be a useful enrichment medium for the isolation of this organism from cow and pig fecal samples, each inoculated with 16 organisms. Observations recorded seemed to suggest that contaminant bacteria perhaps outgrow and mask
S. choleraesuis
. An incubation period of 24 to 30 hr was found optimum for the three enrichment broths. A longer period was detrimental in the case of TTB but not with selenite broth and BGMB.
Antigenicity of Influenza Vaccine from Bovine Cell Cultures
Authors: Leiderman Eduardo , Mogabgab William J.
Published: December 2020

An experimental vaccine prepared from influenza virus strains propagated in bovine kidney cell cultures, purified by zonal centrifugation, and further treated with ether was studied in man for the incidence of clinical reactions and hemagglutination-inhibition antibody levels induced. The results were equivalent to those obtained in a simultaneous study made with a commercially licensed influenza vaccine derived from viruses propagated in the embryonated egg and also purified by zonal centrifugation, but not treated with ether. Comparison of the macromethod and the micromethod for determination of hemagglutination-inhibition antibody titers revealed that lower initial titers and lesser increments in antibody levels following vaccination were obtained by the microtechnique.
Bordetella pertussis
Serotypes in the United States
Authors: Eldering Grace , Holwerda Jack , Davis Ausma , Baker Julia
Published: December 2020

To determine the
Bordetella pertussis
serotypes currently causing whooping cough in the United States, recently isolated cultures from different geographic areas were studied. Specific adsorbed antisera were prepared in our laboratory and used in both tube and slide agglutination tests. Among the 177 cultures isolated during 1966 and 1967 in seven states and one Canadian province, the predominant serotype was 1.3 (or 1.3.6), represented by 85% of the cultures. Fifteen cultures were serotype 1.2.3.4.6. The 376 cultures isolated in the Grand Rapids area during the last 30 years showed a changing pattern from serotype 1.2.3 during the early years to the currently prevailing 1.3 (or 1.3.6). During the 2-year study period, seven cultures of
B. parapertussis
were isolated in Michigan, and seven were received from other states. One culture of
B. bronchiseptica
, recovered from a child in Boston, was sent to us.