bluuebunny/crossref_metadata_2025 huggingface dataset:
A Precise Method for Replicating Suspension Cultures of Mammalian Cells
Authors: Weirether Francis J. , Walker Jerry S. , Lincoln Ralph E.
Published: December 2020

A simple, readily assembled shaker-culture system for the cultivation of mammalian cells is described. No specialized glassware and equipment were used in this system, which consists of an Erlenmeyer flask fitted with a breather-sampling assembly. This unit was employed to quantitate the effects of several variables, including medium ingredients, serial transfers, and freezing and storage on two variants of the L-cell line. This system is reproducible and precise and allows for growth of cells in suspension for extended periods of time. Large numbers of cells can be mass-produced. Many replicates can be run simultaneously to yield data for statistical analysis.
Behavior of
Salmonella typhimurium
During Manufacture and Curing of Cheddar Cheese
Authors: Goepfert J. M. , Olson N. F. , Marth E. H.
Published: December 2020

Nine vats of stirred-curd granular cheddar cheese were made with whole milk contaminated with
Salmonella typhimurium
after pasteurization. Enumeration of salmonellae by the most probable number technique during manufacture and curing showed that these organisms multiplied rapidly during manufacture until the curd was salted. Thereafter and throughout the curing period, the salmonellae declined in number at a rate dependent on the temperature of curing. Evidence is presented indicating that the production of volatile fatty acids in the curd during curing may be responsible for this decline.
Identification of
Micrococcaceae
in Clinical Bacteriology
Authors: Branson Dorothy
Published: December 2020

The cellular morphology, identifying physiological characteristics, and a key to the human genera of
Micrococcaceae
are presented with flow charts for identification of aerobic and anaerobic isolates. These flow charts can be amended as desired, depending upon the degree of accuracy desired.
Micrococcaceae
isolates in a 350-bed private general hospital during a 15-week period are tabulated to show relative numbers of the different genera and species, with their probable relationship to infection or contamination. Only 11 of the 220
Micrococcaceae
isolates were not
Staphylococcus
; no
Sarcina
or
Peptococcus
were isolated. Of the
Staphylococcus
isolates, 61% were
S. epidermidis
. Almost 18% of the
S. aureus
isolates were coagulase-negative. Of the
S. aureus
isolates, 80% of the coagulase-positive isolates were infecting agents, as were 67% of the coagulase-negative
S. aureus
isolates, compared to only 48% of
S. epidermidis
isolates. Two of four
Gaffkya
isolates but only one of seven
Micrococcus
isolates were infecting agents. If coagulase production is used as the sole criterion for speciation of staphylococci, and
Micrococcus
is not differentiated from
Staphylococcus
, the term “coagulase-negative staphylococci” does not differentiate three distinct levels of pathogenicity. Coagulase-negative
S. aureus
is more virulent than
S. epidermidis
or
Gaffkya
, which are more virulent than
Micrococcus
or
Sarcina
.
Serological Studies of the T and Tumor Antigens of the Oncogenic Simian Adenoviruses
Authors: Gilden Raymond V. , Kern Jerome , Heberling Richard L. , Huebner Robert J.
Published: December 2020

Tumor-specific antigens and antisera were prepared for eight of the oncogenic simian adenoviruses. Complement-fixation tests revealed three distinct serological subgroups. This grouping was maintained in studies of virus-infected cells (T antigens) although high titered preparations were obtained for only the major subgroup I. The current grouping is as follows: (I) SV1, SV11, SV25, SV33, SV34, SV38; (II) SV20, SV23; (III) SA 7. Antigens from each subgroup were rapidly inactivated at 56 C, and group II and III antigens were also markedly inactivated at 37 C. One of the tumors (SV1) also contained SV40 T antigen, suggesting origin from a simian adenovirus-SV40 “hybrid.”
Microtiter Method for the Evaluation of Viable Cells in Bacterial Cultures
Authors: Fung Daniel Y. C. , Kraft Allen A.
Published: December 2020

A microtiter technique was investigated as a means of evaluating viable cells in bacterial cultures. Parallel experiments were performed employing the conventional agar plate method along with the microtiter procedure. Statistical analyses showed that the correlation between the two methods was highly significant. With this new method, many samples were analyzed simultaneously, and readable results were obtained in 12 to 15 hr. Other advantages of this method were substantial savings of time, space, and materials. Also, the applicability of this method to estimates of mixed bacterial populations was demonstrated by studying the associative growth of two bacterial cultures.
Factors Influencing Agnotobiotic Cultures of the Rumen Ciliate,
Entodinium simplex
Authors: Jarvis B. D. W. , Hungate R. E.
Published: December 2020

The nutrition of
Entodinium simplex
was studied, with foliage of bluegrass (
Poa pratense
), perennial ryegrass (
Lolium perenne
), and grains of wheat (
Triticum vulgare
) as substrates in agnotobiotic cultures.
Entodinium
grew poorly when the substrates were autoclaved; better growth was obtained when the substrates were sterilized with ethylene oxide vapor. The concentration of ethylene oxide and the amount of moisture influenced the sterility and nutritional adequacy of the treated substrate. Autolysates and hydrolysates of mixed rumen protozoa stimulated growth. Protozoal extracts did not replace factors destroyed by autoclaving. Clarified rumen fluid assisted the cultivation of entodinia from small inocula but was detrimental to established cultures. Success of cultures was influenced by the medium used to grow the inoculum as well as by the medium inoculated. The results indicated that the composition of the bacterial population influences the growth of
E. simplex
.
Sugar and Alcohol Stabilization of Yeast in Sweet Wine
Authors: Kunkee Ralph E. , Amerine Maynard A.
Published: December 2020

Secondary fermentation of sweet wine was prevented by the Delle stabilization procedure. For this procedure, advantage is taken of the inhibitory effects of high concentrations of sugar as well as of alcohol. Thus, relatively small amounts of wine spirits were added to fermenting musts to obtain stability, as compared to the conventional procedure in which larger amounts of alcohol are added and the inhibitory effect of alcohol only is considered. The Delle value is a function of the concentrations in the wine, after spirits addition, of alcohol and sugar. Delle values which gave stable wine were dependent on time of alcohol addition, on strain of wine yeast, and on composition of wine spirits. Fractional addition of spirits, concentration of SO
2
, and clarity of must had little effect on the Delle value. Sensory comparison of wines especially prepared for tasting by the Delle procedure and by the conventional procedure showed the wines made by the Delle procedure to be superior in quality. Under proper storage conditions, the Delle wines were shown to be microbiologically stable and resistant to wine spoilage organisms.
Production of Phosphatase by
Aspergillus awamori
var.
kawachii
in a Low Phosphate Medium
Authors: Ohta Yoshiyuki , Ikeda Katsuhiko , Ueda Seinosuke
Published: December 2020

The effect of phosphate on the production of phosphatases by
Aspergillus awamori
var.
kawachii
was studied. In a high phosphate medium, little phosphatase was produced, and the phosphatase activity was predominately for β-glycerophosphate. In a low phosphate medium, the production of phosphatase was increased and activity for glucose-6-phosphate predominated. Medium containing 1 mg of phosphorus per 100 ml was optimal, and the amount of phosphatase produced in this medium was about 200 times that produced in a high phosphate medium. By means of column chromatography on diethylaminoethyl cellulose, the phosphatase produced in the high phosphate medium was found to be eluted mainly at fraction e; the phosphatase of the low phosphate medium was separated into fractions a, b, c, and d. Thus, the phosphatase fractions produced in the low phosphate medium were different from those of the high phosphate medium. Since no specific effect on the production of esterases was observed when various phosphate esters were used as substrates, the enzymes of phosphate metabolism appear to be activated by nonspecific phosphate sources.
Particle Size Distribution of
Serratia marcescens
Aerosols Created During Common Laboratory Procedures and Simulated Laboratory Accidents
Authors: Kenny Michael T. , Sabel Fred L.
Published: December 2020

Andersen air samplers were used to determine the particle size distribution of
Serratia marcescens
aerosols created during several common laboratory procedures and simulated laboratory accidents. Over 1,600 viable particles per cubic foot of air sampled were aerosolized during blending operations. More than 98% of these particles were less than 5 μ in size. In contrast, 80% of the viable particles aerosolized by handling lyophilized cultures were larger than 5 μ. Harvesting infected eggs, sonic treatment, centrifugation, mixing cultures, and dropping infectious material produced aerosols composed primarily of particles in the 1.0- to 7.5-μ size range.
Attached Growth of
Sphaerotilus
and Mixed Populations in a Continuous-flow Apparatus
Authors: Dias F. F. , Dondero Norman C. , Finstein M. S.
Published: December 2020

The effects of NH
4
Cl concentration, organic nitrogen compounds, glucose concentration, dissolved oxygen concentration, and flow rate on the attached growth of pure cultures of
Sphaerotilus natans
and of a mixed population in a continuous-flow apparatus are described. Low concentrations of NH
4
Cl and oxygen, and high flow rates resulted in attached populations that were dominated by
Sphaerotilus
. The conditions that allowed maximal attached growth in pure culture did not correspond to the conditions that promoted attached growth of
Sphaerotilus
in a mixed population.
Effect of the Route of Inoculation on Antibody Formation in Guinea Pigs Immunized with Parainfluenza Virus Vaccines
Authors: DeMeio Joseph L.
Published: December 2020

The efficiency of the intramuscular route of immunization of guinea pigs was compared with the intraperitoneal route when trivalent parainfluenza virus vaccine was employed as immunogen. When the routes of immunization were compared by effective dose 50, the intramuscular route was more effective. Likewise, a statistical evaluation of conversion rates and of titers revealed significantly higher values for the intramuscular than for the intraperitoneal route to all three components in two of the lots of vaccine tested.
Containment of Microbial Aerosols in a Microbiological Safety Cabinet
Authors: Barbeito Manuel S. , Taylor Larry A.
Published: December 2020

A microbiological safety cabinet was evaluated to determine conditions under which microorganisms might escape. Tests were conducted under three cabinet-closure conditions, various airflow velocities, and different laboratory operations, with 10
5
, 1.1 × 10
5
, and 10
6
microorganisms per cubic foot of cabinet space released per min for 5 min. The data revealed that (i) escape of a human infectious dose is possible when the cabinet is used with the glove panel off; (ii) the number of organisms that escaped from the cabinet increased with a decrease in air velocity; and (iii) an increase in the number of laboratory operations resulted in an increase in the number of organisms that escaped. Thus, when the glove panel was off, the cabinet was only safe for operations that released a small number of microorganisms into the cabinet, whereas the cabinet was safe for operations of significantly greater hazard when used with the glove panel on but with the gloves unattached.
Estimation of Radiation Resistance Values of Microorganisms in Food Products
Authors: Anellis Abe , Werkowski Stanley
Published: December 2020

Several statistical methods, including the conventional technique of Schmidt and Nank, were evaluated for estimating radiation resistance values of various strains of
Clostridium botulinum
by the use of partial spoilage data from an inoculated ham pack study. Procedures based on quantal response were preferred. The tedious but rigorous probit maximum likelihood determination was used as a standard of comparison. Weibull's graphical treatment was the method of choice because it is simple to utilize, it is mathematically sound, and its
ld
50
values agreed closely with the reference standard. In addition, it offers a means for analyzing the type of microbial death kinetics that occur in the pack (exponential, normal, log normal, or mixed distributions), and it predicts the probability of microbial death with any radiation dose used, as well as the dose needed to destroy any given number of organisms, without the need to assume the death pattern of the partial spoilage data. The Weibull analysis indicated a normal type kinetics of death for
C. botulinum
spores in irradiated cured ham rather than an exponential order of death, as assumed by the Schmidt-Nank formula. The Weibull 12
D
equivalent of a radiation process, or the minimal radiation dose (MRD), for cured ham was consistently higher than both the experimental sterilizing dose (ESD) and the Schmidt-Nank average MRD. The latter calculation was lower than the ESD in three of the five instances examined, which seems unrealistic. The Spearman-Kärber estimate was favored as the arithmetic technique on the bases of ease of computation, close agreement with the reference method, and providing confidence limits for the
ld
50
values.
Roles of Microorganisms in the Deterioration of Rockfish
Authors: Lobben J. C. , Lee J. S.
Published: December 2020

Seven species of microorganisms indigenous to fish were inoculated into sterile fish muscle, obtained from
Sebastodes alutus
and
Sebastalobus alascanus
, and the production of total volatile acids (TVA) and total volatile bases (TVB) was determined during storage at 1 C. No production of TVA and TVB was noted in sterile fish, fish inoculated with
Pseudomonas
type III species (PIII-985), or fish inoculated with
Flavobacterium
(F-1070). The inactivity of PIII-985 was due to its low maximal growth level, whereas the inactivity of F-1070 was due to its slow growth rate.
Pseudomonas
type I species (PI-950),
Pseudomonas
type II species (PII-952), and two
Achromobacter
(
Acinetobacter
) species (A-981 and A-70) grew and actively produced TVA and TVB. TVB levels increased steadily even after the microbial number reached a maximum, whereas TVA levels declined toward the end of the storage period. It appeared that a minimal microbial growth level of 10
8
cells/g was needed before detectable levels of TVA or TVB could be produced. Regardless of genera, microorganisms which grew well in fish were able to produce TVA and TVB.
Lactobacilli on Plants
Authors: Mundt J. Orvin , Hammer James L.
Published: December 2020

The distribution, enumeration, and identification of lactobacilli on vegetable plants were studied in an area described geographically as being subtropical and moist. The lactobacilli were obtained, by means of quantitative enrichment procedures in Rogosa's SL broth, from 35.3% of all samples incubated at 32 C, and from 15.4% of the samples incubated at 45 C. Less than 10 lactobacilli/g of plant material were enumerated in 54% of all positive samples. The lactobacilli were found much less frequently and in lower numbers than were streptococci or
Leuconostoc mesenteroides
. The most frequently isolated lactobacillus was very simular to, but not identical with,
Lactobacillus fermenti
. It was aerogenic, grew well at both 15 and 45 C, fermented arabinose, lactose, and sucrose, and liberated ammonia from arginine. Of the identified species,
L. plantarum, L. fermenti
, and
L. brevis
were the most frequently isolated, whereas
L. casei, L. viridescens, L. cellobiosus, L. salivarius
, and
L. buchneri
were obtained from small numbers of samples. The widespread but sporadic distribution of lactobacilli in low numbers seems to indicate that these organisms do not normally thrive on plant surfaces. A ternary cycle, beginning with intestinal waste, followed by mechanical distribution to and among plants, and return to the host via the oral cavity, is suggested.
Appearance of Mouse-Lethal Toxin in Liquid Cultures of
Bordetella pertussis
Authors: Lane A. G.
Published: December 2020

The mouse-lethal toxin present in liquid cultures of most smooth strains of
Bordetella pertussis
is known to originate in the cytoplasm of the organism but to be most lethal for mice when released into the supernatant fluid. It is also recognized that cell degeneration and lysis occur in liquid cultures during the stationary and decline phases of growth. For these reasons, it is generally believed that most of the toxicity demonstrable in liquid cultures at the time of harvest is released during the later stages of cultivation, when high alkalinity and aging of cells favor lysis. However, the results reported here have indicated that high levels of mouse-lethal toxicity arise during very early log phase and that the peak of toxicity is reached before the end of the log phase. No further increase in toxicity was observed during stationary and decline phases. The very early appearance of toxicity could not be explained by the presence in the inoculum of a proportion of dead and degenerating cells, and it is concluded that the toxin is produced mainly by actively growing cells. This was confirmed by tests on organisms growing in continuous culture. Electron-microscopic examination of cells from a very early log-phase culture revealed the presence of large numbers of small vesicles on the cell walls of about 5% of the population. It is suggested that these vesicles may be associated with the releases of toxin from living cells. It is concluded that no useful reduction in the toxicity of cultures would result from harvesting before the end of the log phase of growth.
Rapid Fluorescent-Antibody Staining Technique
Authors: Martin Alice J. , Bigwood Robert F.
Published: December 2020

The rapid fluorescent-antibody staining technique described by Kellogg and Deacon for staining
Neisseria gonorrhoeae
and
Treponema pallidum
was applied to fluorescent-antibody tests for group A streptococci and enteropathogenic
Escherichia coli
. Results obtained with this staining technique were compared with results using the conventional staining procedure; excellent correlation was obtained. Considerable time and materials were saved by using the rapid method; it was also found completely satisfactory.
Influence of Bacterial Infection on Serum Enzymes of White Rats
Authors: Woodward John M. , Camblin Mark L. , Jobe Martin H.
Published: December 2020

Infection of white rats with
Francisella tularensis (Pasteurella tularensis)
and
Salmonella typhimurium
and exposure to the endotoxin of
S. typhimurium
stimulated significant increases in various serum enzymes including aldolase, lactate dehydrogenase, phosphohexose isomerase, isocitrate dehydrogenase, and glutamate-oxalacetate transaminase. The rates of changes in enzymatic activity after infection were directly related to the size of infecting dose and to the type of infective agent employed. Tularemic infection stimulated excessive changes in enzyme activity, whereas salmonellosis and endointoxication elicited less pronounced alterations of relatively short duration. Changes observed in serum enzymes after exposure to these agents reflect the severe liver damage and extensive systemic involvement noted in tularemia as opposed to more localized and less intensive tissue damage occurring during salmonellosis and endointoxication.
Protein Quality of the Bacterium
Hydrogenomonas eutropha
Authors: Calloway Doris H. , Kumar Adarsh M.
Published: December 2020

Hydrogenomonas eutropha
cells harvested from semicontinuous autotrophic culture and washed free of substrate contain about 13% of nitrogen on a dry-solids basis. Biological value and digestibility of the bacterial nitrogen were determined in the rat by use of an abbreviated Mitchell-Thomas nitrogen balance technique and casein as the standard protein. Casein nitrogen was 99% digestible, and that of both whole boiled and sonically ruptured bacterial cells was 93%. Biological value of casein and the bacterial preparations was uniformly 77%. Amino acid composition of the bacteria, as in the case of casein, indicates a first limitation of sulfur-containing amino acids. These compositional features suggest that
H. eutropha
may be potentially valuable as a protein supplement in animal feeds.
Direct Bacterial Count as a Rapid Freshness Test for Fish Fillets
Authors: Lerke Peter , Farber Lionel
Published: December 2020

Comparison of various indices of deterioration of refrigerated fish fillets showed that the direct bacterial count can be used to predict the storage life of the foodstuff. For direct counts, a thin film made from fillet surface material was spread on a microscope slide, stained, and read. Initial counts were found to correlate well with keeping quality; a period of freshness of 24 or 48 hr at 5 C could be reliably predicted. Preliminary data indicated that hypoxanthine estimation could probably also be used for the prediction of shelf life but that the relative complexity of the procedure detracted from its usefulness.
Predominant Catalase-negative Soil Bacteria. I. Streptococcal Population Indigenous to Soil
Authors: Gledhill William E. , Casida L. E.
Published: December 2020

Streptococci related to
Streptococcus sanguis
were shown to represent a major segment of the bacterial flora of certain soils. Upon initial isolation, these streptococci were quite pleomorphic and displayed morphological characteristics common to several other genera of bacteria, but after prolonged cultivation on laboratory media the isolates demonstrated a typical streptococcal morphology. It was proposed that a requirement for correction of the control mechanisms affecting growth rate and cell wall synthesis in part might explain the difficulty encountered in isolation of these organisms from soil and their initial pleomorphism and cultural instability. The possible role of these soil organisms as etiological agents of disease and the occurrence of other groups of streptococci in soil were discussed.

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Frequency of R Factor-mediated Multiple Drug Resistance in
Klebsiella
and
Aerobacter
Authors: Hinshaw Virginia , Punch James , Allison Marvin J. , Dalton Harry P.
Published: December 2020

A comparative study was done on the transfer frequency of R factors from 90 strains of multiple drug-resistant
Aerobacter
and 81 strains of
Klebsiella
to
Escherichia coli
CSH-2 (F
-
,

met
-
, pro
-
, Nal-r

). The most common resistance patterns for the
Aerobacter
isolants were ampicillin streptomycin chloramphenicol tetracycline and ampicillin streptomycin chloramphenicol tetracycline kanamycin neomycin; for the
Klebsiella
isolants, the most common resistance pattern was ampicillin kanamycin streptomycin tetracycline chloramphenicol neomycin. R factors were isolated from 14.1% of the
Aerobacter
strains; 61.5% of these R factors harbored R determinants for ampicillin streptomycin tetracycline. R factors were isolated from 79.1% of the
Klebsiella
strains; four R factors were isolated with significant frequency; streptomycin chloramphenicol kanamycin neomycin, 37.5%; ampicillin streptomycin tetracycline kanamycin neomycin, 14.1%; ampicillin streptomycin tetracycline, 12.5%; and streptomycin chloramphenicol tetracycline, 12.5%.

Chloramphenicol, kanamycin, and neomycin resistance was rarely transferred from the
Aerobacter
strains, although over 50% of the clinical isolants possessed resistance to these antibiotics. In contrast, over 75% of the
Klebsiella
strains transferred resistance to chloramphenicol, kanamycin, neomycin. Highest frequency of transferred resistance to individual drugs in the
Aerobacter
strains was to streptomycin (14.8%), whereas in the
Klebsiella
group resistance to four drugs was transferred at a very high frequency: streptomycin (80.8%), chloramphenicol (78.5%), kanamycin (76.4%), and neomycin (75.9%).
Survival of T3 Coliphage in Varied Extracellular Environments. I. Viability of the Coliphage During Storage and in Aerosols
Authors: Warren James C. , Hatch Melvin T.
Published: December 2020

The objective of this study was to determine the feasibility of using airborne T3 coliphage as a viral tracer in microbial aerosols. Although T3 coliphage was relatively stable when stored either at temperatures ranging from 21 to 37 C or in the frozen state at -20 C, there was a 2-log loss in infectivity when stored for 72 days at 4 C. Either agitation of stored coliphage suspensions held at 31 C or wide fluctuations in storage temperature produced an increased loss of infectivity. In the airborne state, freshly prepared coliphage and stored coliphage behaved similarly, with survival diminishing as the relative humidity (RH) was lowered. The greatest loss occurred during the first five min following aerosolization. The results showed that only under certain conditions of temperature and relative humidity can T3 coliphage be used as a satisfactory aerosol tracer.
Sporulation, Heat Resistance, and Biological Properties of
Clostridium perfringens
Authors: Nishida S. , Seo N. , Nakagawa M.
Published: December 2020

A sporulation medium for 134
Clostridium perfringens
strains, including types A, B, C, D, E, and F, was devised according to Grelet's observation that sporulation occurred when cultural environment became limited in any nutritional requirement indispensable for the growth of the organism. Sporulation took place most prominently when 10% cooked-meat broth (
p
H 7.2) containing 3% Proteose Peptone and 1% glucose was used for the preculture and 2% Poli Peptone medium (
p
H 7.8) was used for the subculture medium. Sometimes, terminal spores could be observed. A correlation between sporulation and heat resistance was examined by use of
C. perfringens
strains isolated from samples heated at different temperatures. Almost all strains isolated from unheated samples and from those heated at lower temperatures gave rise to spores in our sporulation medium, but the spores were weakly heat-resistant, whereas strains isolated from samples heated at 100 C for 60 min were highly heat-resistant but sporulated poorly. A majority of these heat-resistant strains were non-gelatinolytic and definitely salicin-fermenting.
Interacting Factors That Influence Long-term Storage of Live
Pasteurella tularensis
Vaccine and Rift Valley Fever Virus
Authors: Klein Frederick , Walker Jerry S. , Mahlandt Bill G. , Carter Richard C. , Orlando Michael D. , Weirether Francis J. , Lincoln Ralph E.
Published: December 2020

Studies were conducted on the interaction of various parameters which affect the storage stability and growth potential of liquid cultures of
Pasteurella tularensis
live vaccine strain (LVS) and Rift Valley fever virus Van Wyk strain (RVFV). Storage variables studied with LVS included four storage temperatures (4, -20, -65, -175 C), single and multiple freeze-thaw cycles, two freezing and two thawing rates (slow and fast), various inoculum levels (1, 3, 5, and 10%) for the determination of growth potential, and the retention of immunizing potential (mice and guinea pig) after storage. Neither the freezing rate nor the number of freeze-thaw cycles seriously affected the growth of LVS after storage at -175C; however, the slow rate of thaw proved deleterious as were all temperatures of storage except -175 C after 1 year of storage, as shown by both criteria of evaluation. RVFV produced in two combinations of cell lines and media (LM cell line-199 peptone medium and LDR cell line-Eagle's minimum essential medium) was stored at three serum levels (10, 20, 40%), three
p
H values (6.2., 7.0, 7.8), and three temperatures (-20, -65, -175 C). These studies indicated: (i) virus produced in the LDR cell line and Eagle's medium was more stable than that produced in the LM cell line and 199 peptone medium for either short- or long-term storage; (ii) serum levels did not affect stability; and (iii) low
p
H resulted in losses during long-term storage under all conditions tested. Thus, cryogenic storage is advantageous for stock culture maintenance of bacteria and viruses and for other similar applications.
Disintegration of Microorganisms and Preparation of Yeast Cell Walls in a New Type of Disintegrator
Authors: Ŕeháćek J. , Beran K. , Bićík V.
Published: December 2020

Microbial cells were disintegrated in a new type of rotary disintegrator with a disc stirrer by a combination of shear force layers, collisions, and rolling of glass beads which were brought into motion by the stirrer. The rate of disintegration at a given dry bed volume of Ballotini beads and a given volume of cell suspension is proportional to the peripheral velocity of the stirrer up to 18 m/sec. Horizontal arrangement of the stirrer increases the effectiveness about five times; 100% disintegration of yeast cells was achieved under optimal conditions within 72 sec at a concentration of 3.5g (dry weight)/100 ml of suspension, and within 96 sec at a concentration of 10.5g (dry weight)/100ml. At 17.5 g (dry weight)/100 ml, the stirrer began to slip. The cell walls of yeast were obtained at the desired degree of crushing and the course of purification was determined by infrared spectral analysis.
Homologous Interference by an Actively Multiplying Noncytopathic Strain of Bovine Virus Diarrhea-Mucosal Virus
Authors: Singh K. V.
Published: December 2020

Reduction in plaque size of cytopathic strains of bovine virus diarrhea-mucosal disease virus was determined to be a more sensitive indicator than number for detecting the interference induced by the noncytopathic strain of virus in cell cultures.
Simple Medium for Pigment Production by the Erythrasma Diphtheroid
Authors: Cohen Stephen N. , Nickolai Dorothy
Published: December 2020

A simple method for the isolation and identification of the causative diphtheroid of erythrasma,
Corynebacterium minutissimum
, utilizes Muiller-Hinton Agar.
Acetamide Agar Medium Selective for
Pseudomonas aeruginosa
Authors: Hedberg Mary
Published: December 2020

A synthetic base of acetamide and salts in agar permitted isolation of small numbers of
Pseudomonas aeruginosa
from swarming
Proteus
and other gram-negative species.
Modified Sabouraud Medium Containing Neomycin and Polymyxin
Authors: Cohen Stephen N.
Published: December 2020

A commercially available antibiotic mixture effectively decreased overgrowth of Sabouraud medium by gram-negative flora frequently found in the sputum of hospitalized patients.
Bioassay for Hamycin and Amphotericin B in Serum and Other Biological Fluids
Authors: Shadomy Smith , McCay Judith A. , Schwartz Stephen I.
Published: December 2020

A bioassay suitable for measuring concentrations of the polyene antifungal agents hamycin and amphotericin B in biological fluids is described. By using
Paecilomyces varioti
as the indicator organism, sensitivity of the bioassay was found to be in the range of 0.01 to 0.02 μg/ml. A linear dose-response curve was obtained with amphotericin B; the curve for hamycin was curvilinear. In a series of assays, hamycin serum levels in the range of 0.01 to 3.5 μg/ml were measured; with amphotericin B, serum levels in the range of 0.015 to 0.175 μg/ml were measured in patients receiving orthodox intravenous medication and as high as 9.0 μg/ml in one patient treated with extraordinarily high doses of the drug.
Cell Dispersal Methods for Increasing Yield from Animal Tissues
Authors: Kammer Herbert
Published: December 2020

An improved method for increasing cell yield from animal tissues is described. The current technique differs from the classical, primarily in that the tissues were perfused with trypsin in situ and cell dispersal was completed by trypsinization either at 4 or 37 C but without prior mincing of the tissue. Increased yields of 75% were obtained. Mechanical damage to tissue by mincing was presumed to be the greatest single source of injury to cells. The adoption of the trypsin perfusion technique reduced the number of animals needed to prepare an equivalent quantity of tissue culture.
Study of Delayed Hypersensitivity to Myxoviruses Induced by Vaccines
Authors: Tremonti Lawrence P. , Jackson George Gee
Published: December 2020

The delayed hypersensitivity response of guinea pigs to Bacillus Calmette-G�erin (BCG) and myxovirus vaccines was investigated by use of the techniques of skin testing and inhibition of macrophage migration. A serum antibody response to the injected vaccines was readily demonstrable. Parainfluenza type 2 virus consistently failed to induce a delayed hypersensitivity state in 15 animals, even with the use of a virus adjuvant emulsion. Respiratory syncytial virus occupied an intermediate position in that positive delayed type skin tests of an erythematous nature were elicited following inoculation, but only two of seven guinea pigs yielded a positive migration inhibition test. In mumps-inoculated animals, skin testing gave rise to erythematous delayed skin reactions which varied from 0 to 20 mm in size. Migration inhibition could be demonstrated in 7 of 21 animals. In almost all guinea pigs inoculated with BCG, large, indurated, erythematous skin reactions were elicited, and inhibition of macrophage migration was readily demonstrated. The degree of skin reactivity was positively correlated with inhibition of macrophage migration. If the skin reaction to a specific antigen exceeded 9 mm of erythema, that antigen also inhibited macrophage migration. Skin testing proved to be the most sensitive indicator of viral hypersensitivity. Migration inhibition was demonstrated only when a greater than 8-mm skin reaction was evoked. This cellular hypersensitivity appeared to be a qualitative phenomenon, the expression of which could be heightened by the use of adjuvant. The applicability and sensitivity of the migration inhibition technique is considered relative to its use for in vitro monitoring of effects of viral vaccine inoculations.
Fecal Microflora in Healthy Persons in a Preindustrial Region
Authors: Mata Leonardo J. , Carrillo Celina , Villatoro Elba
Published: December 2020

Procedures for quantitating the fecal microflora of man were described. Special attention was given to criteria for characterizing the culturable aerobic, Micro-aerophilic, and anaerobic bacteria. Three groups of healthy persons were studied: wholly breast—fed infants (2 to 4 month-olds), weanlings (1 to 2 year-olds), and adults. In breast-fed children, bifidobacteria predominate and outnumber by one or several logs all other culturable bacteria. The fecal flora of wholly breast-fed infants is “simpler” and more numerous [10
11
to 10
12
per g (wet weight) of feces than that of the adult 10
2
to 10
11
per g]. In the adult, gram-negative anaerobic bacilli (bacteroides) outnumber all other groups by a factor of 1 log or more. Weanlings receiving an adult-type diet, but still breast-fed, showed a flora intermediate between that of the wholly breast-fed infant and that of the adult, but more similar to the latter. Anaerobes always constitute the predominant component of the culturable flora of children and adults and are always found in large numbers under conditions of health. The aerobes are significantly less numerous, and vary widely in their number and in the frequency with which they appear in feces.
Infectious Pancreatic Necrosis Virus: Lyophilization and Subsequent Stability in Storage at 4 C
Authors: Wolf Ken , Quimby M. C. , Carlson C. P.
Published: December 2020

Infectious pancreatic necrosis virus (ATCC strain VR # 299) was lyophilized with different additives and stored at 4 C. Ampoules were assayed at 2 days, at 1, 3, and 6 months, and at 1, 3, and 4 years. Processing losses were least and subsequent maintenance of infectivity was best in skim milk, lactalbumin hydrolysate, and lactose. Quantitative data are given in tabular form.
Concentration and Purification of Herpesviruses (Simplex, Cytomegalo, and EB) in a Zonal Ultracentrifuge
Authors: McCombs Robert M.
Published: December 2020

By using the BXIV zonal ultracentrifuge rotor, it was possible to efficiently concentrate and partially purify members of the herpesvirus group by pelleting the virus onto a double sucrose cushion.
Hydrolysis of Phenoxymethyl Penicillin into 6-Aminopenicillanic Acid with Spores of Fusaria
Authors: Singh Kartar , Sehgal S. N. , V�zina Claude
Published: December 2020

Hydrolysis of phenoxymethyl penicillin into 6-aminopenicillanic acid with spores of fusaria was studied.
Evaluation of Factors Related to Growth of Rift Valley Fever Virus in Suspended Cell Cultures
Authors: Walker Jerry S. , Carter Richard C. , Klein Frederick , Snowden Shirley E. , Lincoln Ralph E.
Published: December 2020

The effect of several controlled variables on the peak titer and fold increase of Rift Valley fever virus grown in suspension culture on two variants of Earle's L cell, L-DR and L-MA clone 1-1, was studied. No significant amount of cell-associated virus was found at 24 hr, indicating a release of virus soon after its formation. Mild sonic treatment of the virus produced in serum-free medium increased the infective titer about 10×. This difference was not observed with virus produced in medium supplemented with serum. Peak titer was not affected by medium used during the infection period, by multiplicity of inoculum (MOI), or by initial cell concentration within the test range of 10
4
to 2 × 10
6
cell/ml. Cell strain employed influenced titer, because the L-DR cell did not produce virus efficiently at low MOI and low initial cell concentration. The time of peak titer and fold replication was dependent on MOI and initial cell concentration. Differences in virus propagation in monolayer and suspension systems are discussed.
Role of Alcoholic Intermediates in Formation of Isomeric Ketones From
n
-Hexadecane by a Soil
Arthrobacter
Authors: Klein D. A. , Henning F. A.
Published: December 2020

A soil
Arthrobacter
species isolated from an Oregon soil was capable of transforming
n
-hexadecane to a series of ketonic products, the 2-,3-, and 4-hexadecanones, with evidence for accumulation of 2- and 3-hexadecanols as oxidative intermediates when yeast extract or peptone was used as a growth substrate. The accumulation and participation of internal alcohols in this type of hydrocarbon transformation has not been previously reported. In the absence of yeast extract or peptone, growth from low-level inocula was not observed when
n
-hexadecane or two oxidation products, 2-hexadecanol and 3-hexadecanone, were used as substrates. However, washed resting cell suspensions of the organism transformed 2-hexadecanol, or a mixture of 2-,3-, and 4-hexadecanols, to the corresponding ketones without lag, indicating the possible constitutive nature of the alcohol dehydrogenase enzyme(s) carrying out this reaction. The addition of glucose to these resting cells stimulated transformation of
n
-hexadecane to alcoholic and ketonic oxidation products. Formation of isomeric internal alcohols appears to be a limiting step in ketone formation by this
Arthrobacter
isolate.
Enhanced Recovery of Airborne T
3
Coliphage and
Pasteurella pestis
Bacteriophage by Means of a Presampling Humidification Technique
Authors: Hatch M. T. , Warren J. C.
Published: December 2020

This paper reports a series of experiments in which two methods of collecting airborne bacteriophage particles were compared. A standard aerosol sampler, the AGI-30, was evaluated for its competence in measuring the content of bacteriophage aerosols. It was used alone or with a prewetting or humidification device (humidifier bulb) to recover T
3
coliphage and
Pasteurella pestis
bacteriophage particles from aerosols maintained at 21 C and varied relative humidity. Collection of bacteriophage particles via the humidifier bulb altered both the initial recovery level and the apparent biological decay. Sampling airborne bacteriophage particles by the AGI-30 alone yielded data that apparently underestimated the maximal number of potentially viable particles within the aerosol, sometimes by as much as 3 logs.
Systemic Antifungal Activity of Pyrrolnitrin
Authors: Gordee Robert S. , Matthews Thomas R.
Published: December 2020

The antifungal activity of pyrrolnitrin, previously shown to be effective against superficial infections, was evaluated against experimental systemic mycoses. Pyrrolnitrin was inhibitory in vitro at <0.78 to 100 μg/ml to
Candida albicans, Cryptococcus neoformans, Blastomyces dermatitidis, Sporotrichum schenckii
, and
Histoplasma capsulatum
. Pyrrolnitrin activity was reduced about 90% in sera. After multiple subcutaneous doses of pyrrolnitrin at 20 mg/kg, activity was recovered in mouse blood and urine as well as kidney, liver, and brain homogenates. Multiple daily doses (50 mg/kg) of this antibiotic were effective in reducing by 74% the number of viable cells of
C. albicans
recovered from kidney homogenates. Multiple doses (15 mg/kg) resulted in a 74% reduction in the number of
C. neoformans
from brain homogenates. Pyrrolnitrin was ineffective in reducing the recovery of
B. dermatitidis
or
H. capsulatum
from liver or spleen homogenates of infected mice. When compared with amphotericin B, hamycin, 5-fluorocytosine, and saramycetin, this antibiotic was less effective. This study indicates that pyrrolnitrin would have limited usefulness as a systemic antifungal agent.
Experimental Transmission of
Enterobacteriaceae
by Insects. I. Fate of
Salmonella
Fed to the Hide Beetle
Dermestes maculatus
and a Novel Method for Mounting Insects
Authors: Julseth R. M. , Felix Jacob K. , Burkholder Wendell E. , Deibel R. H.
Published: December 2020

A method of mounting insects was devised. The procedure is simple to perform and facilitates quantitative bacteriological studies of feces with a minimal possibility of cross contamination. By this method, it was observed that approximately 10
7
cells of
Salmonella
were required for passage through the intestinal tract. Multiple doses of this magnitude were necessary to initiate intestinal infection. The numerical considerations cast doubt that
Dermestes
is involved significantly in the dissemination of
Salmonella
in the environment of food and feed plants.
Automated Technique for the Detection of Hemagglutinins to Sheep Erythrocytes
Authors: Cleeland Roy , Grunberg E.
Published: December 2020

The Technicon autoanalyzer system used for the detection of homologous human hemagglutinins has been modified for the detection of hemagglutinins to sheep red blood cells. Antibody quantitation was obtained by plotting the optical density (OD) readings of peak heights of a serially diluted reference serum versus the serum dilutions. When the OD of the peak height of an unknown sample fell within the linear portion of the plot, a direct determination of the antibody titer was made. If the OD of the sample fell outside the linear portion, dilutions of the sample were carried out until a direct reading could be made. Assay by this method of at least 140 samples was possible within a day. Titers obtained with the autoanalyzer agreed very closely with those obtained by manual titration.
Production of Ochratoxin A by
Aspergillus ochraceus
in a Semisynthetic Medium
Authors: Davis N. D. , Searcy J. W. , Diener U. L.
Published: December 2020

Aspergillus ochraceus
NRRL 3174 produced 29 mg of ochratoxin A per 100 ml of nutrient medium consisting of 4% sucrose and 2% yeast extract. Ochratoxin A was the sole metabolite present in the chloroform extracts of the growth medium. Trace amounts of ochratoxin B were produced in a 1% yeast medium, and a comparatively large amount of ochratoxin B was produced in media containing 16 and 32% sucrose.
Chemical States of Bacterial Spores: Dry-Heat Resistance
Authors: Alderton Gordon , Snell Neva
Published: December 2020

Mature bacterial spores can be manipulated by chemical pretreatments between states sensitive and resistant to dry heat. The two chemical forms of the spore differ in dry-heat resistance by about an order of magnitude. Log survivor curves for each chemical state were approximately straight lines. The temperature dependence of dry-heat resistance for each chemical state was similar to that usually found for dry-heat resistance. A method of testing spore resistance to dry heat has been designed to minimize artifacts resulting from (i) change of chemical state during the test, (ii) effects of water vapor activity, (iii) incomplete recovery of spores from the test container and clumping of spores. Implications of the existence of different chemical resistance states for experimental strategy and testing of dry-heat resistance are discussed.
Separation and Quantitation of Neomycins as Free Base by Paper Chromatography
Authors: Majumdar Mrinal K. , Majumdar S. K.
Published: December 2020

Neomycin B and C and neamine were separated as free bases in the solvent system methyl ethyl ketone-
tert
-butyl alcohol-methanol-6.5 N NH
4
OH (16:3:1:6 v/v) and quantitatively estimated.
Effect of Temperature on Growth of
Salmonella
in Rehydrated Skim Milk from a Food-Poisoning Outbreak
Authors: Julseth R. M. , Deibel R. H.
Published: December 2020

Low numbers of salmonellae in a dried skim milk sample that was implicated in an outbreak of salmonellosis grew rapidly upon rehydration and incubation.
Antimycobacterial Activity of Rifampin Under In Vitro and Simulated In Vivo Conditions
Authors: Stottmeier K. D. , Kubica G. P. , Woodley C. L.
Published: December 2020

Minimal inhibitory concentrations of rifampin for different species of mycobacteria were determined in 7H-10 agar medium and Lowenstein-Jensen egg medium. When rifampin was incorporated into egg medium, approximately 90% of its activity was lost. The stability of rifampin was tested during storage at different temperatures and concentrations. When tested in agar medium, a combination of isoniazid (INH) and rifampin inhibited multiple drug-resistant strains of
Mycobacterium intracellulare,
but under simulated in vivo conditions the drugs did not eliminate these same organisms. Drug-resistant mutants of
M. intracellulare
multiplied during an 8-day period when exposed 10 hr daily to the INH-rifampin regimen. However, combinations of rifampin and INH reduced drug-resistant mycobacterial populations by 99%, an effect which could not be enhanced by the addition of either erythromycin, ethionamide, or cycloserine.
Antipseudomonal Activity of α-Sulfoaminopenicillins
Authors: Price K. E. , Chisholm D. R. , Leitner F. , Misiek M. , Gourevitch A.
Published: December 2020

A series of penicillins characterized by the presence of a sulfoamino or a modified sulfoamino group in the side chain was subjected to in vitro antimicrobial screening tests. Although the most potent members of the series were less active than benzylpenicillin against gram-positive bacteria and comparably active against most gram-negative bacteria, they were, on the average, 8 to 16 times more effective against strains of
Pseudomonas aeruginosa.
In other comparative laboratory tests against
P. aeruginosa,
these compounds were about as active as carbenicillin and four to eight times more active than ampicillin. An examination of structure-activity relationships indicated that maximal potency was obtained with penicillins having an α-(aromatic or heteroaromatic)-α-sulfoaminoacetamido side chain. The compound with an α-phenyl group was comparable in activity to those having an α-(2- or 3-thienyl) group, whereas any modification in position or structure of the α-sulfoamino group reduced activity. Results of studies with a cell-free
P. aeruginosa
β-lactamase suggest that the marked inhibitory effects of α-sulfoamino penicillins for
P. aeruginosa
can be attributed, at least in part, to their high degree of resistance to this enzyme. Some derivatives, however, had weak antipseudomonal activity, despite possessing a high degree of β-lactamase resistance.