bluuebunny/crossref_metadata_2025 huggingface dataset:
Sampling Submicron T1 Bacteriophage Aerosols
Authors: Harstad J. Bruce
Published: December 2020

Liquid impingers, filter papers, and fritted bubblers were partial viable collectors of radioactive submicron T1 bacteriophage aerosols at 30, 55, and 85% relative humidity. Sampler differences for viable collection were due to incomplete physical collection (slippage) and killing of phage by the samplers. Dynamic aerosols of a mass median diameter of 0.2 μ were produced with a Dautrebande generator from concentrated aqueous purified phage suspensions containing extracellular soluble radioactive phosphate as a physical tracer. There was considerable destruction of phage by the Dautrebande generator; phage titers of the Dautrebande suspension decreased exponentially, but there was a progressive (linear) increase in tracer titers. Liquid impingers recovered the most viable phage but allowed considerable (30 to 48%) slippage, which varies inversely with the aerosol relative humidity. Filter papers were virtually complete physical collectors of submicron particles but were the most destructive. Fritted bubbler slippage was more than 80%. With all samplers, phage kill was highest at 85% relative humidity and lowest at 55% relative humidity. An electrostatic precipitator was used to collect aerosol samples for particle sizing with an electron microscope. The particle size was slightly larger at 85% relative humidity than at 30 or 55% relative humidity.
Geosmin, an Earthy-Smelling Substance Isolated from Actinomycetes
Authors: Gerber N. N. , Lechevalier H. A.
Published: December 2020

Geosmin, an earthy-smelling substance, has been isolated from several actinomycetes. Production of 1 mg per liter of whole broth was obtained from
Streptomyces griseus
LP-16. After preliminary separations, pure geosmin was isolated in milligram amounts by gas chromatography. Geosmin is a neutral oil, with an approximate boiling point of 270 C, which contains carbon and hydrogen, but no nitrogen. It undergoes a reaction with acid to give odorless argosmin, a neutral oil, with an approximate boiling point of 230 C, which contains only carbon and hydrogen. Specific rotation and ultraviolet- and infrared-absorbtion spectra were determined for both.
Site of Action of Certain Antibacterial Heterocyclic Quaternary Ammonium Compounds
Authors: Cox W. A.
Published: December 2020

The site of action of related mono- and bis-quinaldinium compounds was investigated in
Staphylococcus aureus
and
Bacillus megaterium
. The effects of these compounds on cell morphology and on protoplast formation and fragility were studied, and the distribution of C
14
-labeled quinaldinium compound in cell fractions was measured. The latter studies showed that a major part of the quaternary compound penetrates the cell, leaving a very small quantity associated with the cell wall. Similar antibacterial effects were seen with both the mono- and bis-quinaldinium compounds studied, and these effects were comparable with antibacterial properties of known cationic surface-active antibacterial agents.
Sensitivity of Agar Overlay Method for the Recognition of Enteroviruses
Authors: Gabrielson Mary O. , Hsiung G. D.
Published: December 2020

Comparison of the agar overlay technique with the fluid culture technique for isolation and identification of enteroviruses showed the former to be useful: (i) for isolation of enterovirus when the number of virus particles was too small to produce detectable cytopathic effect (CPE) in fluid cultures, (ii) for isolation of echovirus 22 which did not produce detectable CPE in fluid cultures, (iii) as an aid to rapid differentiation of enteroviruses, and (iv) for differentiation of viruses in mixed infections. Nonpolio enterovirus isolation experience in the New Haven area over a 4-year period is presented. It was concluded that the agar overlay technique is both useful and relatively simple for routine examination of clinical specimens in a diagnostic laboratory.
Bacteria Responsible for the Retting of Brazilian Flax
Authors: Rosemberg J. A.
Published: December 2020

Twenty-two species of bacteria were isolated from
Linum usitatissimum
stored for retting.
Achromobacter parvulus, Clostridium beijerinckii, C. saprogenes, C. saccharoacetoperbutylicum, C. perenne
, and
Pseudomonas aeruginosa
and its achromogenic variety are retting agents. The last species mentioned performs the retting in only 72 hr. This is the first time
A. parvulus
has been shown to be a retting agent.
Three Methods of Assessing the Mutagenic Action of Ultraviolet Radiation on the Fungus
Emericellopsis glabra
Authors: Schwartz L. J. , Stauffer J. F.
Published: December 2020

Colony isolates of the fungus
Emericellopsis glabra
, developing from ultraviolet (UV)-irradiated conidia, were examined for variability on the basis of colony morphology, loss of antibiotic-producing capacity on plate assay, and loss of ability to grow in minimal medium. The latter two of these methods are considered to be more objective and reliable in determining the degree of variability induced by UV radiation in this fungus. The highest frequency of variants is obtained at UV dosages which reduce spore survival to levels of 5 to 15%.
Growth of Lactic Acid Bacteria in Waste Waters of Vegetable-Processing Plants
Authors: Mundt J. Orvin , Larsen Sandra A. , McCarty I. E.
Published: December 2020

Waters used in washing, blanching, cooling, and conveying vegetables during processing for freezing were filtered, sterilized, and inoculated with
Streptococcus faecalis, S. lactis
, or
Lactobacillus plantarum
. The contents of total nitrogen and total solids were determined, and ninhydrin tests and Benedict's tests for reducing sugars were performed. Substances positive to the ninyhydrin tests and also capable of supporting the growth of the bacteria to high levels of population were found in waters used to blanch cut green beans, but not in the cooling or conveying waters. They were found only in waters following slicing of blanched whole beans. They were also present in waters used in processing purple hull peas at all stages, but only in the waters used to blanch and cool lima beans. The substances were present in waters used to wash and blanch squash, but only in the waters used to blanch greens; they were not found in the cooling waters during the handling of either vegetable. No waters used in the processing of okra yielded a positive ninhydrin test, nor did they support the growth of the lactic acid bacteria.
Thermal Inactivation of Staphylococcal Enterotoxin B in Veronal Buffer
Authors: Read R. B. , Bradshaw J. G.
Published: December 2020

The times and temperatures required to inactivate staphylococcal enterotoxin B were studied by use of the double-gel-diffusion technique to assay enterotoxin. Enterotoxin B (99 +% pure) was suspended in 0.04 M Veronal buffer, dispensed into borosilicate vials, and the vials were sealed and heated in an oil bath. An amount of 30 μg/ml of this toxin was reduced to less than 0.7 μg/ml in 103.0, 87.1, 70.5, 57.2, 39.1, 27.6, 16.4, and 12.0 min, respectively, at temperatures of 96, 99, 101.7, 104.4, 110, 115.6, 121, and 126.7 C. The end point for enterotoxin inactivation by gel diffusion was identical to that by intravenous injection of cats. Limited studies with crude enterotoxin B showed that the crude preparation was slightly more thermostable. The respective
D
values of crude and purified enterotoxin B were 64.5 and 52.3, 40.5 and 34.4, 29.7 and 23.5, 18.8 and 16.6, and 11.4 and 9.9 min at temperatures of 99, 104.4, 110, 115.6, and 121 C. The
z
value for purified enterotoxin B was 32.4 C. The experimental activation energy was 20,700 cal/g mole, standard enthalpy of activation at 120 C was 19,900 cal/g mole, standard entropy of activation at 120 C was -21.4 cal/g mole K, and the standard free energy of activation at 120 C was 28,200 cal/g mole.
Bacteriological Survey of the Frozen Prepared Foods Industry
Authors: Surkiewicz Bernard F.
Published: December 2020

During Food and Drug Administration inspections of 12 imitation cream pie producers, 453 finished product samples and 350 line samples were collected and analyzed bacteriologically. Sanitary conditions in the plants varied from good to poor and, in general, were reflected in the bacteriological results. The survey revealed that, in the great majority of cases, frozen imitation-cream pies produced in plants operating under good conditions of sanitation had the following bacteriological content: (i) a most probable number (MPN) of fewer than three
Escherichia coli
cells per gram (i.e., absent from all tubes in the methodology employed), (ii) an average MPN of fewer than 50 coliforms per gram (10 or more pies), (iii) the absence of coagulase-positive staphylococci in 0.1-g portions, and (iv) an aerobic plate count of fewer than 25,000 per gram (geometric mean of 10 or more pies).
Yeasts in Ensiled High-Moisture Corn
Authors: Burmeister Harland R. , Hartman Paul A.
Published: December 2020

A total of 1,365 yeasts were selected from ensiled high-moisture corn at various stages in the ensiling process to determine the sequence and relative numbers of yeast species. The yeast species most frequently isolated from freshly harvested corn were
Candida parapsilosis
and
C. intermedia
; these two species were isolated infrequently after the third week of storage. Species of yeasts that predominate after the 12th day of storage were
Hansenula anomala
(66% of the isolates studied) and
C. krusei
(26% of the isolates studied). The preponderance of
H. anomala
and
C. krusei
in ensiled corn is believed to be associated with the ability of these two species to assimilate lactic acid.
Influence of Diet and Age on Bacterial Counts of Ileal Digesta and Feces Obtained from Young Calves
Authors: Hartman P. A. , Morrill J. L. , Jacobson N. L.
Published: December 2020

The numbers of total aerobes, total anaerobes, and facultatively aerobic lactobacilli, streptococci, and coliform bacteria were determined in samples of ileal digesta and feces from calves 0, 3, 6, 9, and 12 hr after feeding milk, or milk with sucrose or starch added. Differences in the flora could be attributed to diurnal variation (time from feeding to sampling), source of the sample (ileal versus fecal), nature of the dietary carbohydrate (lactose versus lactose plus sucrose versus lactose plus starch) and age of the animal (on a diet of milk plus sucrose).
Quantitative Ecology of Psychrophilic Microorganisms
Authors: Stokes J. L , Redmond Mary L.
Published: December 2020

To obtain information on the importance of psychrophiles in nature, 95 samples of soil, water, mud, and various foods were quantitatively assayed for their content of psychrophilic bacteria and fungi and also for mesophilic and thermophilic bacteria and fungi. Thousands to millions of psychrophilic bacteria were present per gram of soil and represented 0.5 to 86% of the bacterial population. Also, about 25% of the fungi in uncultivated soil were psychrophilic. In stream and river water, psychrophilic bacteria constituted 16 to 47% of the bacterial population; in lake water, 41 to 76%; and in lake mud, 11 to 33%. Large numbers of psychrophilic bacteria were present in dairy products, meats, and other foods, and accounted for 35 to 93% of the bacterial population of meats. In contrast, thermophilic bacteria usually comprised 1% or less of the bacterial population in all of the materials examined. The data indicate that psychrophiles are both ubiquitous and numerous in nature, and probably play important roles in the cycles of matter.
Polypeptide Antibiotic 4205 from a Soil Bacillus
Authors: Shaw Myrtle , Brown Rachel , Martin Ann G.
Published: December 2020

Antibiotic complex 4205, a basic polypeptide, was isolated from a nonsporulating bacillus. It was separated into two components, A and B, each composed of 2,4-diaminobutyric acid, isoleucine, leucine, phenylalanine, serine, and valine, but in different proportions, namely, 4:1:2:1:1:1 and 5:1:3:1:2:2, respectively. There was also an ether-soluble moiety in each that had the characteristics of a fatty acid. This antibiotic differed chemically from other known antibiotics. Both A and B were effective against gram-positive and gram-negative bacteria, cytotoxic for various tissue cell lines, highly toxic for mice by intraperitoneal injection, and toxic for chick embryos by the amniotic and allantoic routes, but not by yolk-sac inoculation. Antibiotic, in amounts sublethal by the allantoic route, inhibited the multiplication of 10 to 100 minimal infective doses of influenza type A, PR8, in embryonated eggs.
Inactivation of Foot-and-Mouth Disease Virus by Interaction of Dye and Visible Light
Authors: Fellowes O. N.
Published: December 2020

The inactivation of foot-and-mouth disease virus was studied by means of the interaction of neutral red, Toluidine Blue, and methylene blue with visible light. The virus, Type A, strain 1, CANEFA of Argentine origin, was grown in tissue culture and tested in the crude and clarified state. Virus and dye were mixed and incubated together at 4 C for 45 min in the dark, or were mixed and immediately exposed to the visible light source without prior incubation together. Mixtures of crude virus and dye, under any of the experimental conditions used, did not inactivate more than 1 to 2 logs of viral infectivity when held in the dark or when exposed to light during a period of 45 min. Complete inactivation of virus was achieved when clarified virus and dye were mixed and immediately exposed to the visible light source for 15 min. Prior incubation of clarified virus and dye permitted inactivation by methylene blue only, whereas no incubation prior to exposure resulted in three of the dyes contributing to inactivation. A concentration of 6 μg of neutral red, Toluidine Blue, methylene blue, and crystal violet was used per milliliter of virus suspension. Crystal violet was not a good viral inactivator under the conditions of the experimentation. Inactive virus induced the formation of neutralizing antibodies in adult chickens and mice. The antibody titer stimulated by the antigen treated with methylene blue and visible light was probably significant.
Formation of 6-Aminopenicillanic Acid, Penicillins, and Penicillin Acylase by Various Fungi
Authors: Cole M.
Published: December 2020

Several penicillin-producing fungi were examined for ability to produce 6-aminopenicillanic acid (6-APA) and penicillin acylase. 6-APA was found in corn steep liquor fermentations of
Trichophyton mentagrophytes, Aspergillus ochraceous
, and three strains of
Penicillium
sp. 6-APA was not detected in fermentations of
Epidermophyton floccosum
although penicillins were produced. 6-APA formed a large part of the total antibiotic production of
T. mentagrophytes
. The types of penicillins produced by various fungi were identified by paper chromatography, and it was found that all cultures produced benzylpenicillin.
T. mentagrophytes
and
A. ochraceous
showed increased yields of benzylpenicillin and the formation of phenoxymethylpenicillin in response to the addition to the fermentation medium of phenylacetic acid and phenoxyacetic acid, respectively. Washed mycelia of the three
Penicillium
spp. and two high penicillin-yielding strains of
P. chrysogenum
possessed penicillin acylase activity against phenoxymethylpenicillin.
A. ochraceous, T. mentagrophytes, E. floccosum
, and
Cephalosporium
sp. also had penicillin acylase activity against phenoxymethylpenicillin. Only two of the above fungi,
T. mentagrophytes
and
E. floccosum
, showed significant penicillin acylase activity against benzylpenicillin; in both cases it was very low. The acylase activity of
A. ochraceous
was considerably increased by culturing in the presence of phenoxyacetic acid. It is concluded that 6-APA frequently but not invariably accompanies the formation of penicillin, and that penicillin acylase activity against phenoxymethylpenicillin is present in all penicillin-producing fungi.
Production and Stabilization of Cells of
Bacillus popilliae
and
Bacillus lentimorbus
Authors: Costilow Ralph N. , Sylvester Charles J. , Pepper Rollin E.
Published: December 2020

Bacillus popilliae
and
B. lentimorbus
grew most rapidly and to the greatest extent in aerated cultures at 30 to 32 C with oxygen absorption rates of 1 mmole of O
2
per min per liter, or above. The control of
p
H also increased the maximal populations attained. Media were developed which consistently produced cell populations of about 10
9
within 24 to 48 hr in aerated cultures of these two species. The acetic acid produced in highly aerated cultures was shown not to be responsible for the rapid loss of cell viability in stationary phase cultures. However, H
2
O
2
was very lethal to cells of
B. popilliae
, and this species is known to have the capacity to produce it. Stationary-phase cells were partially stabilized by reducing the availability of oxygen after 24 hr of incubation on a shaker, and the addition of low levels of glucose further stabilized the cells. The most stable cells were those produced in a medium in which 4% Trypticase (BBL) and 0.1% barbituric acid were incorporated. A high percentage of these cells contained refractile bodies visible under a phase microscope. Although these bodies were not heat-resistant and lacked other characteristics of endospores, cells in cultures containing them had reasonably high viability for extended periods, as compared with those in control cultures.
β-Galactosidase for Distinguishing between
Citrobacter
and
Salmonella
Authors: Pickett M. J. , Goodman R. E.
Published: December 2020

Detection of β-galactosidase with the aid of
o
-nitrophenyl-β-
d
-galactopyranoside (ONPG) was examined as a means for distinguishing between
Citrobacter
and
Salmonella
. Several factors which influence sensitivity and reliability of the test were studied. A bacteriostat, sodium azide, was included to permit prolonged incubation of weak and negative strains of enteric bacilli. By the procedure described, salmonellae gave negative ONPG tests; all of 171 strains of
Citrobacter
gave positive tests.
Microorganisms of the Upper Atmosphere
Authors: Timmons Durward E. , Fulton John D. , Mitchell Roland B.
Published: December 2020

An aircraft-mounted air-sampling system for the collection of microorganisms from the upper air is described. The system is highly suitable for use in upper air sampling from an aircraft because (i) it is an isokinetic system, (ii) it is simple to operate, (iii) it employs a dry filter, (iv) the volume sampled can be easily determined, and (v) it operates efficiently at all altitudes and ambient temperatures.
Microorganisms of the Upper Atmosphere
Authors: Fulton John D.
Published: December 2020

The relationship between frontal activity and the micropopulation of the atmosphere at altitude is described. It is shown that certain of the meteorological events associated with frontal activity quantitatively modify the micropopulation of the atmosphere. Precipitation associated with frontal passage reduces the micropopulation at altitude, whereas frontal activity with high levels of associated surface and atmospheric turbulence results in great increases in micropopulations of the upper atmosphere—particularly in those situations where surface conditions are conductive to the development of dust.
Effect of Lactic Acid Bacteria on Growth of
Staphylococcus aureus
Authors: Kao Claudia T. , Frazier W. C.
Published: December 2020

Cultures of lactic acid bacteria, mostly from foods, were tested for their effect on the growth of
Staphylococcus aureus
in Trypticase Soy Broth (BBL). Some of the effectors, e.g.,
Streptococcus faecalis, S. faecium, Lactobacillus lactis, L. brevis
, and
Leuconostoc mesenteroides
, stimulated growth of
S. aureus
during early hours of growth, especially at higher temperatures of incubation, but most cultures were inhibitory, and some (
S. faecium
and
L. mesenteroides
) were even killing by the time of attainment of the maximal phase of growth of the
Staphylococcus
. Low-temperature meat lactobacilli and
Leuconostoc dextranicum
inhibited
S. aureus
at 10, 15, 20, and 25 C throughout its growth.
Streptococcus faecalis
var.
liquefaciens
inhibited at these temperatures and at 30 and 37 C, as well. When the ratio of effectors to staphylococci in the inoculum was 100:1, the three enterococci, the meat
Lactobacillus
, and
L. dextranicum
prevented the attainment of 5 × 10
6
staphylococci per milliliter at 15 C, and all but the meat
Lactobacillus
did so at 22 C. A ratio of 1:1 accomplished similar results at 15 C, except that
S. aureus
was only delayed for 12 hr by
S. faecalis
. A ratio of 1:100 usually was ineffective. In general, the more effector bacteria there were in the inoculum, the greater was the overall inhibition (or stimulation) of
S. aureus
. Inhibition was most effective at 10 or 15 C, less so at 20 or 25 C, and least at 30 or 37 C, whereas stimulation during early growth was greater at the higher temperatures. Results with different strains of the effectors and with two strains of
S. aureus
were similar, for the most part.
Comparison of Chlorine, Bromine, and Iodine as Disinfectants for Swimming Pool Water
Authors: Koski T. A. , Stuart L. S. , Ortenzio L. F.
Published: December 2020

Studies on the germicidal activity of chlorine, bromine, and iodine were made by use of the Association of Official Agricultural Chemists official first action method for determining effectiveness of swimming pool water disinfectants. In this procedure, 0.3 ppm of available chlorine as chlorine gas has activity equivalent to 0.6 ppm of available chlorine in the buffered sodium hypochlorite control when
Escherichia coli
is used as the test organism. With
Streptococcus faecalis
as the test organism, 0.45 ppm of available chlorine as gaseous chlorine gives activity equivalent to the control. Liquid bromine at 1.0 ppm is as effective as the 0.6 ppm of available chlorine hypochlorite control with
E. coli
as the test organism, but 2.0 ppm of liquid bromine is necessary to provide activity equivalent to the 0.6 ppm of available chlorine control when
S. faecalis
is employed. With iodine as metallic iodine, 2.0 ppm is necessary to provide a result equivalent to the 0.6 ppm of available chlorine control with both
E. coli
and
S. faecalis
. In the various systems tested, gaseous chlorine was the most active form of available chlorine; liquid bromine provided the most active form of bromine, and metallic iodine provided the most active form of iodine.
Rapid Quantitative Serological Assay of Staphylococcal Enterotoxin B
Authors: Weirether Francis J. , Lewis Evelyn E. , Rosenwald Albert J. , Lincoln Ralph E.
Published: December 2020

A simple, rapid method, based on the Oudin single diffusion technique, is described for the quantitative assay of staphylococcal enterotoxin B. The method yields reproducible results without close control of such assay variables as temperature, antiserum dilution, and assay time, provided that the ionic strength is maintained above 0.2
n
sodium chloride equivalent.
Survival of Bacteria on Metal Surfaces
Authors: Wilkinson T. R.
Published: December 2020

Survivor curves were determined for
Serratia marcescens, Sarcina lutea, Pasteurella tularensis
, and
P. pestis
deposited from the airborne state onto metallic surfaces and subsequently stored at various humidities and temperatures. Cells of all species tested remained alive longest in a dry atmosphere, except that cells of
S. marcescens
survived best in a saturated atmosphere. Survival decreased most rapidly at the intermediate humidity level for three of the test organisms, yet
P. tularensis
died most rapidly in a saturated atmosphere. An increase in temperature decreased survival of
P. pestis
and
P. tularensis
.
Bacteriostatic, Fungistatic, and Algistatic Activity of Fatty Nitrogen Compounds
Authors: Hueck Hendrik J. , Adema Dorothea M. M. , Wiegmann John R.
Published: December 2020

A total of 164 fatty nitrogen compounds, consisting of quaternary ammonium compounds, alkylamines,
N
-alkyl-1, 3-propylene diamines, substituted amino hydroxystearonitriles, substituted amino hydroxystearyl amines, and nitrogen-containing surfactants, were screened for bacteriostatic, fungistatic, and algistatic activity. The most active compounds were dodecylamine and dodecylamine acetate. A number of compounds were very active against gram-negative bacteria. Most of the surfactants were virtually nontoxic to all of the test organisms.
Pigmented Bacteriostatic Substances and Amino Acids Produced by
Phlebopus sulphureus
and
Phlebopus lignicola
Authors: Madhosingh C.
Published: December 2020

The pigmented bacteriostatic substances and ninhydrin-reactive compounds produced in culture by sporophores, stipes, and residual medium of
Phlebopus sulphureus
and
P. lignicola
were studied chromatographically. Acetone extracts of both species demonstrated bacteriostatic activity against
Bacillus subtilis
and
Escherichia coli
, the maximal inhibition zone being 13 mm. The chloroform extract was inactive. Six compounds, mainly yellow, extracted in ethyl alcohol and separated by chromatography, were common to the sporophore of
P. sulphureus
and the stipes of
P. lignicola
. Eight amino acids, mainly sulfur-containing, were identified chiefly from the mature sporophore of
P. sulphureus
.
Hemagglutination-Inhibition Method and Immunofluorescence Staining with Venezuelan Equine Encephalomyelitis Virus
Authors: Shepel Michael
Published: December 2020

Hemagglutination and fluorescent antibody (FA) are compared for the direct detection of virus devoid of host cells. A determination was made of the minimal number of tissue plaque-forming units of Venezuelan equine encephalomyelitis virus that could be detected by the hemagglutination technique. Similar concentrations of the virus in bovine albumin borate saline, Brain Heart Infusion broth (Difco), and demineralized water were tested by the FA technique. Somewhat higher concentrations of the virus in bovine albumin borate saline were used in the hemagglutination-inhibition test. The quantitative hemagglutination procedure employed for these studies was carried out at 37 C for 75 min with variations in concentration of goose red cells. As a result of lowering the red cell concentration, smaller concentrations of virus were detected. The direct FA staining procedure applied to slide preparations containing known numbers of tissue culture plaque-forming units of virus was negative. Adsorbed viral antigen on agglutinated goose erythrocytes was visualized by direct and indirect FA techniques.
Use of Cheese Whey for Vitamin B
12
Production
Authors: Bullerman L. B. , Berry E. C.
Published: December 2020

The suitability of cheese whey as a substrate for vitamin B
12
production by
Propionibacterium shermanii
was studied. It was found that with a given level of whey solids a definite amount of yeast extract was required to give maximal yields of vitamin B
12
. Of the levels of materials studied, 10% whey solids and 1.5% yeast extract gave the best yields of vitamin B
12
. Most of the lactose of the whey had been utilized in all flask cultures after 168 hr at 29 C.
Use of Cheese Whey for Vitamin B
12
Production
Authors: Bullerman L. B. , Berry E. C.
Published: December 2020

The patterns of growth and vitamin formation by
Propionibacterium shermanii
in whey were similar to the patterns established in other substrates. The vitamin formation was observed during the latter part of the fermentation after the organism approached maximal growth. Lactose utilization by the organism corresponded to the logarithmic-growth phase of the organism. Analyses of the dried culture showed a large increase of vitamin B
12
in the fermentation solids compared with unfermented dried whey. A feed analysis showed a notable increase of protein and a large decrease in nitrogen-free extract of the dried fermentation solid compared with dried whey.
Effect of Temperature and Relative Humidity on Survival of Airborne Columbia SK Group Viruses
Authors: Akers T. G. , Bond Sheila , Goldberg L. J.
Published: December 2020

Three strains of the Columbia SK (Col-SK) group of viruses [Mengo, Maus Elberfeld (ME), and Col-SK viruses] have been studied in the airborne state. All three strains were found to give identical aerosol decay patterns at 16 or 26 C, when held at the same relative humidity (RH). During the first 5 min of aerosol storage time at 16 C, virus inactivation was RH-dependent, with survival maximal at either high (greater than 80%) or low (less than 5%) RH. After 5 min at 16 C, further inactivation, regardless of RH, was insignificant. At 26 C, the effect on survival of RH between 40 and 60% was even more pronounced than at 16 C, and continued after 5 min through 6 hr. Results of this study indicated that the inactivation of airborne Col-SK group viruses was similar to that of other ribonucleic acid (RNA) viruses, particularly poliovirus. Since members of the Col-SK group are picornaviruses, they may well serve as an aerosol model representative of small, ether-resistant, single-stranded RNA viruses.
Use of Bisulfite in the Streptococcal Anti-Nicotinamide Adenine Dinucleotidase Test
Authors: Ayoub Elia M. , Ferretti Joseph J.
Published: December 2020

A major drawback in the performance of the streptococcal anti-nicotinamide adenine dinucleotidase test on a large scale has been the hazard involved in the use of cyanide in assaying nicotinamide adenine dinucleotide. The use of bisulfite instead of cyanide in the performance of this test was investigated. The assays obtained with bisulfite parallel closely those obtained with cyanide, and justify the replacement of cyanide by the safer bisulfite reagent.
Survey of the Sensitivity of Microorganisms to Aflatoxin
Authors: Burmeister H. R. , Hesseltine C. W.
Published: December 2020

Among the 329 microorganisms tested for aflatoxin sensitivity were 30 genera of bacteria, 34 genera of fungi, 4 genera of algae, and 1 protozoan. Twelve species of the genus
Bacillus
, a clostridium, and a streptomycete were inhibited when 30 μg/ml of crude aflatoxin (36% pure) was incorporated into the growth substrate. A strain of
Bacillus brevis
and two of
B. megaterium
were most sensitive to aflatoxin, being inhibited at 10 and 15 μg/ml, respectively.
Microbial Flora of Irradiated Dungeness Crabmeat and Pacific Oysters
Authors: Shiflett Maureen A. , Lee J. S. , Sinnhuber R. O.
Published: December 2020

The microorganisms in Dungeness crabmeat (
Cancer magister
) and Pacific oysters (
Crassostrea gigas
) were identified by the replica-plating and computer analysis method. The initial flora of the shellfish and the flora change during storage at 7 C were determined. The microbial flora shifts in both shellfish were also determined after irradiation at 0.1 and 0.4 Mrad and during subsequent storage at 7 C. The
Achromobacter
species predominated in the initial flora of crabmeat (77.0%). The predominant position of this group increased to 99.2% after 0.1 Mrad and 100% after 0.4 Mrad. A large percentage of
Lactobacillus
was detected in oysters (55.0%). The
Lactobacillus
species were the predominant survivors after 0.1 Mrad (92.4%) but the predominant survivors after 0.4 Mrad were
Achromobacter
species (99.3%).
Liquid Nitrogen Preservation of
Saccharomyces carlsbergensis
and its Use in a Rapid Biological Assay of Vitamin B
6
(Pyridoxine)
Authors: Tsuji Kiyoshi
Published: December 2020

Growth medium as well as freezing menstruum greatly influenced the recovery of
Saccharomyces carlsbergensis
when it was quickly frozen in liquid nitrogen at — 196 C and quickly thawed at 40 C. Nearly 90% recovery in viability was obtained when
S. carlsbergensis
was grown in Trypticase Soy Broth and frozen in vitamin B
6
basal assay medium. The growth phase of
S. carlsbergensis
also influenced recovery after freezing. When
S. carlsbergensis
was grown in Trypticase Soy Broth and frozen in the broth at the logarithmic-growth phase, only 7% viability was retained; the recovery rate increased to 81% when the culture was frozen in the maximal stationary phase. To have the least possible lag period of growth after thawing, a technique called growth-phase conditioning was introduced. After 1 hr of growth-phase conditioning,
S. carlsbergensis
was clearly out of lag phase, and budding was observed. A vitamin B
6
microbiological assay with a 6-hr incubation period and with the use of liquid nitrogen-frozen
S. carlsbergensis
is described.
Uptake of 2,4-Dichlorophenoxyacetic Acid by
Pseudomonas fluorescens
Authors: Wedemeyer Gary
Published: December 2020

Factors influencing the uptake of the sodium salt of 2,4-dichlorophenoxyacetic acid (2,4-D), under conditions in which no net metabolism occurred, were investigated in an effort to determine both the significance of “non-metabolic” uptake as a potential agent in reducing pesticide levels and the mechanisms involved. Uptake of 2,4-D was affected by
p
H, temperature, and the presence of other organic and inorganic compounds. Uptake was more pronounced at
p
H values less than 6, which implies that there may be some interaction between charged groups on the cell and the ionized carboxyl group of 2,4-D. Active transport, carrier-mediated diffusion, passive diffusion, and adsorption were considered as possible mechanisms. Though uptake was inhibited by glucose, sodium azide, and fluorodinitrobenzene (but not by uranyl ion), 2,4-D was not accumulated against a concentration gradient, a necessary consequence of an active transport system, nor was isotope counterflow found to occur. Thus, carrier-mediated diffusion was finally precluded, implying that uptake probably occurs by a two-step process: sorption onto the cell wall followed by passive diffusion into the cytoplasm.
Evaluation of Filters for Removal of Bacteriophages from Air
Authors: Washam C. J. , Black C. H. , Sandine W. E. , Elliker P. R.
Published: December 2020

Glass wool, nonabsorbent cotton, fiberglass filter medium, and a commercial absolute filter were tested for effectiveness in removing aerosolized bacterial viruses under low flow rate (1 ft
3
/min) and high flow rate (10 to 25 ft
3
/min) air-flow conditions. Special equipment was designed for measurement of filter efficiencies under the two air-flow conditions. Under low air-flow rate test conditions, glass wool was only 98.543 to 99.83% efficient, whereas cotton (five layers), fiberglass medium (three layers), and the commercial absolute filter were at least 99.900, 99.999, and 99.999 efficient, respectively. Glass wool and cotton were not used under higher air-flow conditions because they were difficult to assemble in leak-tight filters. The commercial absolute filter and fiberglass medium (three layers) were at least 99.990 and 99.999% efficient, respectively, under the higher air flow conditions. A stainless-steel filter of simple design and fitted with three layers of fiberglass medium was found to be greater than 99.999% efficient in removing high concentrations (20,000 to 70,000 plaque-forming units per cubic foot) of aerosolized bacteriophages from air moving at a low flow rate (1 ft
3
/min). Use of this filter on pressure-vacuum tanks in the fermentation industry is suggested. Several other uses of such a filter are proposed.
Growth of
Desulfovibrio
on the Surface of Agar Media
Authors: Iverson Warren P.
Published: December 2020

Growth of
Desulfovibrio desulfuricans
(API strain) was found to take place in an atmosphere of hydrogen on the agar surface of complex media, including yeast extract (Difco), and Trypticase Soy Agar (BBL) without any added reducing agents. For growth on a 2% yeast extract-agar surface in the absence of hydrogen (nitrogen atmosphere), sodium lactate was required in the medium. Growth on the surface of Trypticase Soy Agar (TSA) under nitrogen took place readily in the absence of an added hydrogen donor. A medium (TSA plus salts) is described based upon the addition of sodium lactate (4 ml per liter), magnesium sulfate (2 g per liter), and ferrous ammonium sulfate (0.05%) to TSA, which appears suitable for the isolation and growth of
Desulfovibrio
on the surface of agar plates in an atmosphere of hydrogen. Sodium lactate does not appear to be essential in this medium for good growth and sulfate reduction in a hydrogen atmosphere, but is essential in a nitrogen atmosphere. Growth of
Desulfovibrio
(hydrogen atmosphere) on the agar surface of media commonly used for its cultivation as well as on an inorganic medium containing bicarbonate as a source of carbon is poor and erratic unless inoculated (
Desulfovibrio
) plates of TSA plus salts are incubated in the same container with plates of these media. This stimulatory effect of incubation with inoculated plates of TSA plus salts medium appears to be due to as yet unidentified volatile material produced by
D. desulfuricans
when growing on this medium. Another volatile material, or possibly the identical material, appears to act similarly to a hydrogen donor.
Thermal Resistance of
Staphylococcus aureus
in Milk, Whey, and Phosphate Buffer
Authors: Walker G. C. , Harmon L. G.
Published: December 2020

The thermal resistance of four strains of coagulase-positive
Staphylococcus aureus
was determined in phosphate buffer, whole milk, skim milk, and Cheddar cheese whey. The logarithmic order of death prevailed until about 99.99 to 99.999% of the organisms were destroyed, after which there was a decline in the rate of destruction. The organisms were more resistant in skim milk and Cheddar cheese whey than in phosphate buffer and whole milk. Thermal resistance varied among strains of
S. aureus
but was consistent with individual strains. As the age of cultures of strain B-120 increased from 12 to 228 hr, the
D
55
values increased from 0.95 to 3.0. The thermal resistance of cultures obtained from survivors to partial thermal destruction was similar to that of the parent cultures.
Biochemical and Physical Changes in Shaken Suspensions of
Pasteurella pestis
Authors: Wessman G. E. , Miller Donna J.
Published: December 2020

Pasteurella pestis
, harvested after 24 to 30 hr of growth in a casein hydrolysate medium at 26 C, was resuspended and shaken in 3% lactose-0.1
m
phosphate buffer for 4 hr at the same temperature. Certain characteristics of these starved cells were compared with those of control cells. No differences in the amounts of cellular carbohydrate or lipid were detected. The concentrations of the principal free amino acids were greater in the shaken cells, except that they contained no measureable arginine, and the normally large pools of intracellular tricarboxylic acid cycle intermediates were reduced. Greater viable-cell counts resulted with the cells that were shaken in lactose buffer than with the control cells when each was incubated at 5 C for several weeks. However, the reduced viabilities were apparent losses caused by the formation of aggregates of cells. The clumping of cells was caused by the polymerization of extracellular nucleic acids, principally deoxyribonucleic acid, that were excreted by the cells. Cell clumping could be partially prevented by prior shaking of the suspended cells, which removed some of the deleterious material, or by the action of crystalline deoxyribonuclease.
Fermentation Studies with
Streptomyces griseus
Authors: Shirato Shiroh , Motoyama Hiroshi
Published: December 2020

Synthetic media for streptomycin fermentation were studied to determine which media gave highest yields of streptomycin. The effect of salts on streptomycin production by
Streptomyces griseus
was examined, and a suitable combination of salts was established in a glucose-casein medium. This medium yielded 3,000 μg/ml of the antibiotic with an inoculum of 1.6%. Substitution of amino acids for casein was examined. Of 17 amino acids tested, best results were obtaind with sodium aspartate. Substitution of ammonium salts was tried, and an excellent streptomycin yield was obtained with a medium containing ammonium citrate.
Role of Methionine in Cephalosporin Synthesis
Authors: Caltrider P. G. , Niss H. F.
Published: December 2020

Methionine has an almost unique stimulatory effect on biosynthesis of cephalosporins (by
Cephalosporium acremonium
). No other sulfur-containing compound tested, except
dl
-methionine-
dl
-sulfoxide, replaced methionine.
dl
-Methionine stimulated the synthesis of cephalosporins when added after the growth phase. The utilization of inorganic sulfate was repressed by methionine. Experiments with
l
-methionine-
S
35
showed that essentially all the sulfur in the cephalosporins was derived from methionine. Sulfur-labeled compounds found in the soluble pool from cells grown with methionine-
S
35
were methionine, homocysteine, taurine, cystathionine, cysteic acid, glutathionine, and cysteine.
dl
-Serine-
3-C
14
was incorporated into the antibiotics, and its utilization was stimulated by methionine.
l
-Cysteine had a sparing effect on the incorporation of methionine-
S
35
and serine-
C
14
into the antibiotics. The data are consistent with the hypothesis that a cystathionine-mediated pathway is operative in the transfer of sulfur between methionine and cysteine.
Anaerobic Simulated Mixed Culture System
Authors: Schaumburg F. D. , Kirsch E. J.
Published: December 2020

A compartmented, autoclavable culture vessel has been developed for the purpose of studying interactive associations of microorganisms which are essential to the anaerobic decomposition of sewage sludge. The unit employs sterile filter membranes to subdivide the interior culture space into individual compartments. Bacteria cultured in one compartment are denied access to adjacent compartments, even though rapid interchange of nutrients and metabolic waste products occurs throughout the unit. The obligate methane-forming anaerobe,
Methanobacillus omelianskii
has been successfully grown and concentrated in this system by use of a synthetic medium reduced with sodium sulfide. The feasibility of using this system to study microbial interactions was, in part, demonstrated by growing
M. omelianskii
in a thoroughly aerated medium which had been biologically reduced by
Escherichia coli
prior to inoculation with the anaerobe. Under this condition of simulated mixed culture growth, the cell yield of both microorganisms, as well as specific metabolic activities ascribed to each organism, was readily monitored.
Variables Affecting the Foam Separation of
Escherichia coli
Authors: Bretz H. W. , Wang S. L. , Grieves R. B.
Published: December 2020

The removal of washed and standardized
Escherichia coli
from distilled-water suspension by foam separation with nitrogen gas and 30 μg/ml of ethylhexadecyldimethylammonium bromide surfactant was increased by increasing the gas rate from 4.3 to 9.3 liters per min and by lowering the port level at which foam was removed from 60.4 to 20.4 cm, but with concomitant increases in foam volumes. The concentrations of cells and of surfactant in the residual suspensions were related to foam volumes; a given number of cells adsorbed a constant amount of surfactant. The addition of from 10 to 500 μg/ml of inorganic salts decreased the total cell removal, with magnesium sulfate producing an anomalously large effect. The addition of surfactant in several doses (compared with a single dose) together with an increase in foaming time from 10 to 24 min produced residual suspensions with lower cell concentrations, and, when salts were present in the initial suspensions, produced lower foam volumes and more concentrated foams.
Medium Without Rumen Fluid for Nonselective Enumeration and Isolation of Rumen Bacteria
Authors: Caldwell Daniel R. , Bryant Marvin P.
Published: December 2020

Colony counts which approximated those in a habitat-simulating, rumen fluid-agar medium (RFM) were obtained in medium 10, a medium identical to the RFM except for the replacement of rumen fluid with 1.5 × 10
-6
m
hemin, 0.2% Trypticase, 0.05% yeast extract, and a 6.6 × 10
-2
m
volatile fatty acid mixture qualitatively and quantitatively similar to that in rumen fluid. Single deletion of Trypticase, yeast extract, or the volatile fatty acid mixture from medium 10 significantly reduced colony counts. Colony counts were also reduced when medium 10 was modified to contain higher concentrations of Trypticase or volatile fatty acids. Significant differences were found between colony counts obtained from diluted rumen contents of animals fed a cracked corn-urea diet, and the colony counts obtained from animals fed either a cracked corn-soyean oil meal or an alfalfa hay-grain diet. Qualitative differences were found between the predominant bacterial strains isolated from rumen contents of animals fed cracked corn diets and strains isolated from animals fed alfalfa hay-grain. Regardless of differences in the predominant flora associated with diet, medium 10 and the RFM supported growth of similar bacterial populations. The results show that medium 10 is suitable for enumeration and isolation of many predominant rumen bacteria.
Thermal Resistance of Salmonellae and Staphylococci in Foods
Authors: Thomas Constance T. , White J. C. , Longrée Karla
Published: December 2020

The heat-resistant
Salmonella senftenberg
775W and two strains of
Staphylococcus aureus
were tested at temperatures up to 68.3 C (71.1 C for
S. senftenberg
) in four different media. From the survival data, decimal reduction times (
D
values) were calculated for each set of conditions, and decimal reduction time curves were constructed for each bacterial strain in each medium. Slopes of decimal reduction time curves (
Z
D
) ranged from 4.52 to 6.38 C with a single exception. There was no statistical heterogeneity among the remaining values. Results were in close agreement with published results of similar studies conducted at somewhat lower temperatures and support the practice of using a slope value (
Z
D
) of 5.56 C for establishing time-temperature relationships for food processing. It is recommended that such a decimal reduction time curve not be extrapolated to temperatures more than 5.56 C higher than those actually tested.
Production of Guanosine-5′-Monophosphate and Inosine-5′-Monophosphate by Fermentation
Authors: Demain A. L. , Jackson M. , Vitali R. A. , Hendlin D. , Jacob T. A.
Published: December 2020

A biotin-requiring coryneform bacterium which produces glutamic acid was mutated to adenine dependency. The adenine-requiring strain, which excreted insoine-5′-monophosphate (IMP), was further mutated to xanthine dependency. As expected, IMP was also excreted by this mutant. The mutant strain was reverted to xanthine independence in an attempt to obtain a culture with an altered IMP dehydrogenase which would be less sensitive to feedback inhibition by guanosine-5′-monophosphate (GMP). A revertant was obtained which produced GMP and IMP, each at 0.5 g per liter. The reversion to xanthine independence had resulted in a concomitant requirement for isoleucine, leucine, and valine. Further mutation to increased nutritional requirements led to culture MB-1802, which accumulated 1 g per liter each of GMP and IMP. Both nucleotides were isolated in pure form. The concentrations of GMP and IMP produced by MB-1802 were four times that of cytidylate, uridylate, or adenylate, indicating that the mechanism of GMP and IMP production was direct and not via ribonucleic acid breakdown.