bluuebunny/crossref_metadata_2025 huggingface dataset:
Ethylene Oxide Gaseous Sterilization
Authors: Ernst Robert R. , Shull James J.
Published: December 2020

The relationships of reaction temperature and concentration of gaseous ethylene oxide to the time required for inactivation of air-dried
Bacillus subtilis
var.
niger
spores are more complex than previously reported. A plot of temperature vs. the logarithm of “thermochemical death time” (TCDT) resulted in a straight line between 18 and 57 C for systems of “high” ethylene oxide concentration. The TCDT values were independent of ethylene oxide concentrations above certain temperature-dependent limits. A given ethylene oxide concentration produced a TCDT curve identical in the upper temperature regions with that for higher concentrations. As the temperature was lowered beyond a critical point, this curve diverged from that for higher concentrations, as a straight line of lesser slope. Thus, a series of curves exists for a range of ethylene oxide concentrations. They are characterized by two segments, both logarithmic, intersecting at a critical temperature for each concentration. The intersecting point is at a temperature inversely related to the ethylene oxide gas concentration. The temperature quotient for the high temperature segments of all systems was 1.8. This value was characteristic for ethylene oxide concentrations of 440 and 880 mg/liter at temperatures above 40.6 and 33.4 C, respectively. Below these critical temperatures, the Q
10
values for the respective systems were 3.2 and 2.3.
Ethylene Oxide Gaseous Sterilization
Authors: Ernst Robert R. , Shull James J.
Published: December 2020

The duration of the equilibration period between admission of water vapor and subsequent introduction of gaseous ethylene oxide to an evacuated sterilizer chamber was studied with respect to its effect on the inactivation of spores of
Bacillus subtilis
var.
niger
under simulated practical conditions. Introduction of a water-adsorbing cotton barrier between the spores and an incoming gas mixture of water vapor and ethylene oxide caused a marked increase in the observed thermochemical death time of the spore populations. This effect was negated by admission of water vapor one or more minutes prior to introduction of ethylene oxide gas. Increases in temperature and relative humidity of the system promoted passage of water vapor through the cotton barriers and diminished their effect.
Antimicrobial Activity of 8-Quinolinols, Salicylic Acids, Hydroxynaphthoic Acids, and Salts of Selected Quinolinols with Selected Hydroxy-Acids
Authors: Gershon Herman , Parmegiani Raulo
Published: December 2020

Seventy-seven compounds were screened by the disc-plate method against strains of five bacteria and five fungi. A new constant was proposed to describe the antimicrobial activity of a compound in a defined system of organisms. This constant includes not only the inhibitory level of activity of the material but also the number of organisms inhibited. This constant, the antimicrobial spectrum index, was compared with the antimicrobial index of Albert.
Clear Media for the Recovery of
Pasteurella tularensis
Authors: Levin M. A. , Trupin J. S. , Cabelli V. J.
Published: December 2020

Peptic digests of blood and hemoglobin were investigated as substitutes for the blood used in the preparation of glucose-cysteine-blood agar plating medium for the recovery of the virulent Schu strain of
Pasteurella tularensis
. Digest media so prepared were found to be satisfactory for the quantitative recovery of freshly grown cells but not for cells stored longer than several days. The addition of appropriate quantities of human plasma, bovine sera, or soluble starch rendered the digest media appropriate for use with stored cultures. The peptic digest-plasma (PDP) and peptic digest-starch (PDS) media were evaluated and found satisfactory for the quantitative recovery of
P. tularensis
Schu from freshly prepared and stored cultures, and from aerosols produced therefrom. With cultures stored longer than 6 weeks, the starch modification (PDS) was not as satisfactory as, and the plasma variation (PDP) was better than, glucose-cysteine-blood agar (GCBA) for the recovery of the organisms. PDP was superior to either GCBA or PDS medium for the recovery of the weakly virulent Jap 4 and Niieg-blue strains of
P. tularensis
.
Viability and Estimation of Shelf-Life of Bacterial Populations
Authors: DeArmon Ira A. , Orlando Michael D. , Rosenwald Albert J. , Klein Frederick , Fernelius Albert L. , Lincoln Ralph E. , Middaugh Paul R.
Published: December 2020

Mathematical concepts associated with the exponential and probit models are developed, and the similarity of the two methods is discussed. Because of its greater flexibility in design, the probit method was used to estimate the shelf-life for four bacterial populations, wet and dry spores of
Bacillus anthracis
and wet and dry cells of
Pasteurella tularensis
. On the basis of data gained by storing these organisms at high temperature, the probit method was used to predict the time at which 50% viability would occur for cells stored at 3 C. A plane passing through a three-space showing change in percentage viability of bacteria was formulated by a multiple regression method. With this functional technique, the percentage viability, expressed as a probit, was linearily related to a logarithm of storage time and storage temperature. The use of this method to study the effect of controlled variables on the viability of cells is demonstrated by comparing the effect of viability associated with three additives used prior to drying. The results of the test gave shelf-life estimates which were too low for all additives; however, the order of stability was ranked properly as confirmed by long-term tests.
Fumigation of Jute Bags with Ethylene Oxide and Methyl Bromide to Eradicate Potato Ring Rot Bacteria
Authors: Richardson L. T. , Monro H. A. U.
Published: December 2020

In a series of full-scale tests, the effectiveness of various fumigant treatments for the eradication of potato ring rot bacteria from bulk lots of contaminated jute bags was evaluated. Survival of these bacteria on infested sample fibers located at various positions within and around a tightly wired bale was determined quantitatively from the growth lag in a liquid medium as indicated by the rate of turbidity development.

Ethylene oxide, though highly toxic to
Corynebacterium sepedonicum
in laboratory tests, failed to penetrate the jute sufficiently to be effective in the interior of a bale. Methyl bromide showed better penetration, but was not sufficiently toxic at practical dosage levels. A mixture of 5% ethylene oxide and 10% methyl bromide achieved complete eradication throughout a bale in an 18-hr exposure period.

On the basis of these results, eradication of ring rot bacteria from contaminated jute bags by fumigation with a combination of these two gases would appear to be feasible under commercial conditions.
Graphical Procedure for Comparing Thermal Death of
Bacillus stearothermophilus
Spores in Saturated and Superheated Steam
Authors: Shull James J. , Ernst Robert R.
Published: December 2020

The thermal death curve of dried spores of
Bacillus stearothermophilus
in saturated steam was characterized by three phases: (i) a sharp initial rise in viable count; (ii) a low rate of death which gradually increased; and (iii) logarithmic death at maximal rate. The first phase was a reflection of inadequate heat activation of the spore population. The second and third phases represented the characteristic thermal death curve of the spores in saturated steam. A jacketed steam sterilizer, equipped with a system for initial evacuation of the chamber, was examined for superheat during normal operation. Measurements of spore inactivation and temperature revealed superheat in surface layers of fabrics being processed in steam at 121 C. The high temperature of the fabric surfaces was attributed to absorption of excess heat energy from superheated steam. The superheated steam was produced at the beginning of the normal sterilizing cycle by transfer of heat from the steam-heated jacket to saturated steam entering the vessel.
Repression of
Staphylococcus aureus
by Food Bacteria
Authors: Troller John A. , Frazier W. C.
Published: December 2020

The effects of environmental factors on the inhibition of an enterotoxin-producing strain of
Staphylococcus aureus
by food bacteria were investigated. Type of medium and temperature of incubation were important factors in determining the amount of inhibition. The pH range of maximal inhibition was found to be 7.4 to 6.2. Availability of oxygen was not a factor. As the ratios of inhibitor to staphylococcus were increased from 1:1 to 10:1 and 100:1, the amount of inhibition was markedly increased. Inhibition occurred in custard, where it increased with increasing ratios of effector to staphylococcus. The repression of the staphylococcus in all media usually was sufficient to be of practical significance.
Antimicrobial Activity of 8-Quinolinol, Its Salts with Salicylic Acid and 3-Hydroxy-2-Naphthoic Acid, and the Respective Copper (II) Chelates in Liquid Culture
Authors: Gershon Herman , Parmegiani Raulo
Published: December 2020

A study was made of the antimicrobial activities of 8-quinolinol and its salts with salicylic acid and 3-hydroxy-2-naphthoic acid in liquid culture. Comparisons of results were made with those obtained by the discplate method. The mechanism of action of copper chelates was discussed.
Respiratory Protection Provided by Five New Contagion Masks
Authors: Guyton H. Gerald , Decker Herbert M.
Published: December 2020

The effectiveness of five recently developed contagion masks in filtering air-borne particles (1 to 5 μ diam) has been reported. One mask, available in four sizes, was 99% efficient. This mask can be reused after sterilization. The other four masks are available in only one size and are intended to be used one time only. Two of these four disposable types were more than 90% efficient but the variability of their respective test results was much greater than that for the reusable mask. The two remaining disposable types were less than 80% efficient. Two of these contagion-mask types were worn by hospital personnel for periods of up to 8 hr to determine the effect of such prolonged use on aerosol filtration efficiency. No significant decrease in filtration efficiency was noted. Physicians, nurses, and other hospital personnel who wear masks will benefit from the increased individual respiratory protection afforded by improved contagion masks. Concurrently, the incidence of hospital patient air-borne infections should be greatly reduced.
Distribution of Bacteria within the Tissue of Healthy Tomatoes
Authors: Samish Zdenka , Etinger-Tulczynska R.
Published: December 2020

Bacteria have been shown to be present in fresh normal tomatoes. The frequency of their presence differed widely between different fields. Bacterial populations within the tomatoes showed a distinct gradient, being largest in the connective tissue at the stem end and decreasing through the central core towards the peripheral and distal tissue. Application of
Serratia
to the sepals of young tomato fruits often resulted in their recovery from within tissue of the mature fruit. These findings lend support to the theory that the bacteria enter the fruit through the connective tissue at the stem end.
Soil Microorganisms of the McMurdo Sound Area, Antarctica
Authors: Boyd William L. , Boyd Josephine W.
Published: December 2020

A study of soil microorganisms of Ross Island and the adjacent mainland was carried out during the brief austral summer of 1961-1962. In some cases, seasonal changes in microbial numbers were observed, although microorganisms could not be detected in some soils. Bacterial species common to temperate regions were isolated from a number of different samples. Thermophilic bacteria were present in some of the soils, and a significant portion of the bacterial population was capable of growth at 2 C. The soil microflora were capable of carrying out certain reactions of the nitrogen cycle at a very slow rate. In addition to temperature, other environmental factors which might influence growth and metabolic activity were discussed.
Occurrence of Enterococci in Animals in a Wild Environment
Authors: Mundt J. Orvin
Published: December 2020

Enterococci were obtained from the feces of 71% of 216 mammals, 86% of 70 reptiles, and 32% of 22 birds sampled in a truly wild environment, the Great Smoky Mountains National Park. Patterns of food dependence and also of species dependence were observed. Among the lower classes of the primarily herbivorous mammals, the enterococci occurred sporadically; however, of the six species of
Sciuridae
, the gray squirrel, and of four species of
Cricetidae
, the red-backed mouse, the enterococci appear to be natural hosts. The enterococci were not obtained from most specimens of moles, shrews, or rabbits but they were obtained from most specimens of bats and from the carnivorous mammals, such as fox, bear, raccon, skunk, and boar.
Streptococcus faecalis
was obtained from 12 reptiles, and a caseolytic variant was obtained from 37 specimens of the reptiles. The strongly reducing, tellurite-tolerant species,
S. faecalis
, its caseolytic variant, and
S. faecalis
var.
zymogenes
were isolated from 127 or 41% of 308 specimens cultured.
S. faecium
was recovered from 87 or 28% of the animals, chiefly from the wild boar (60 of 64 trials) and the black bear.
S. zymogenes
was obtained from 1 of 31 bats, 3 of 12 raccoons, and 1 of 3 owls.
Catalase Activity of Psychrophilic Bacteria Grown at 2 and 30 C
Authors: Frank Hilmer A. , Ishibashi Sandra T. , Reid Ann , Ito June S.
Published: December 2020

Catalase activity was measured in resting-cell suspensions of psychrophilic bacteria grown at 2 and at 30 C. Enzyme activity decreased in both cell-suspension types as harvest age increased. At comparable physiological age, cells grown at 2 C had more catalase than cells grown at 30 C.
Effects of Ultraviolet-Absorbing Compounds on Spore Germination and Cultural Variation in Microorganisms
Authors: Darken Marjorie A. , Swift Marjorie E.
Published: December 2020

A brightener and a nonfluorescent ultraviolet absorber were found to be associated with an increase in the per cent of spore germination and cultural variation in a streptomycete and a
Penicillium
. When the brightener was combined with ultraviolet light, more variants were obtained than with either ultraviolet or brightener alone. This effect occurred at concentrations of brightener substantially greater than those used for fluorescent labeling.
Fungi Associated with Softening of Bisulfite-Brined Cherries
Authors: Lewis J. C. , Pierson C. F. , Powers M. J.
Published: December 2020

Softening of sound, calcium bisulfite-brined cherries was induced fairly quickly by brining them with cherries rotted by
Aspergillus niger, Cytospora leucostoma
, and
Penicillium expansum
, but not with cherries rotted by a variety of other microorganisms, including
Alternaria
sp.,
Aspergillus oryzae, Aureobasidium pullulans, Botrytis cinerea, Cladosporium
sp.,
Mucor racemosus, Rhizopus stolonifer
, and
Sclerotinia fructicola
. Rapid softening was correlated with the presence of a bisulfite-stable polygalacturonase, as demonstrated by a cup-plate test. A survey of naturally rotted cherries suggests the involvement of a bark-canker fungus,
C. leucostoma
, in softening of commercially brined cherries in the Pacific Northwest.
Effect of Environmental and Physiological Conditions on the Phase of Adjustment of
Pseudomonas fragi
Authors: Duncan D. W. , Nickerson J. T. R.
Published: December 2020

The duration of the phase of adjustment of
Pseudomonas fragi
was affected by the physiological age and growth temperature of the inoculum, as well as by the temperature at which the growth curve was determined. Cultures in the exponential phase of growth gave shorter lags than stationary-phase and resting-phase inocula. Inocula from the latter phase gave the longest lags. Inocula grown at the temperature at which the growth curve was determined usually gave the shortest lags: the greater the difference between the incubation temperature of the inoculum and the incubation temperature of the growth curve, the longer the lag. Inocula grown at temperatures below the incubation temperature of the culture tended to produce longer lags than inocula grown at temperatures above the incubation temperature. The combined effect of physiological age and incubation temperature of the inoculum was additive. The effect of the incubation temperature of the culture upon the duration of the lag depended upon the method used to determine this phase. Lags that were measured in physical time (i.e., Lockhart's lag) decreased as the incubation temperature of the culture was increased, within the temperatures used. But Monod's lag, which measures physiological time, did not decrease as the temperature of growth increased but rather appeared to vary around some constant value dependent upon the physiological condition of the culture.
Combined Effects of Ultrahigh Vacuum and Temperature on the Viability of Some Spores and Soil Organisms
Authors: Davis Norman S. , Silverman Gerald J. , Keller Wayne H.
Published: December 2020

Considerably fewer spores of
Bacillus stearothermophilus, B. megaterium
, and
Clostridium sporogenes
were recovered than were spores of
B. subtilis
var.
niger
and
Aspergillus niger
after 4 to 5 days at 53 and 60 C in ultrahigh vacuum. There were no significant differences in the recoveries of these five organisms at 25 C and atmospheric pressure, and after exposure to 25 and -190 C in vacuum. At 60 C, a far greater decrease in viability was demonstrated for
B. stearothermophilus, B. megaterium
, and
C. sporogenes
in ultrahigh vacuum than at atmospheric pressure. Viable
B. subtilis
var.
niger
spores were not detected in an initial 10
7
spores after retention at 90 C and ultrahigh vacuum, and 10
4
spores were viable after 5 days at 90 C and atmospheric pressure from an initial 10
6
spores. Molds and actinomycetes in soil were particularly resistant up to 69 C in vacuum. Actinomycetes were the only soil organisms recovered so far at 120 C.
Effects of Substerilization Doses of Co
60
Gamma Radiation on the Cold-Storage Life Extension of Shucked Soft-Shelled Clams and Haddock Fillets
Authors: Masurovsky E. B. , Goldblith S. A. , Nickerson J. T. R.
Published: December 2020

Total aerobic-facultative and anaerobic (clostridia) macrocolony count data are presented, with analysis and interpretation, for both haddock fillets and shucked soft-shelled clams which received doses of from 50,000 to 800,000 rad of Co
60
gamma rays. These data indicated that haddock fillets may be maintained in good condition at refrigeration temperatures above freezing for about 1 week at 6 C, and approximately 2 weeks at 0 C, when treated with from 50,000 to 150,000 rad of ionizing radiation. In the dose range from 200,000 to 350,000 rad, the storage life may be extended up to some 2 weeks at 6 C, and 3 weeks at 0 C. Treatments in the dose range from 400,000 to 500,000 rad may defer spoilage for about 1 month, and doses of 550,000 to 650,000 rad afford protection against bacterial spoilage up to approximately 1.5 months. At the high substerilization doses of 700,000 to 800,000 rad, haddock fillets may be held for from 2 to 3 months in refrigerated storage before becoming unfit for marketing and consumption. Shucked soft-shelled clams can be held for about 2.5 weeks at 0 C and close to 12 days at 6 C, when given low substerilization doses of from 50,000 to 150,000 rad of ionizing radiation. At doses of from 200,000 to 350,000 rad, the clams may be preserved effectively for periods up to 3 weeks at 0 or 6 C, and some 6 weeks at these temperatures with doses of about 450,000 rad. With treatments of 500,000 to 600,000 rad, the storage life may be extended for some 2 months, and at doses of 650,000 to 800,000 rad the shucked clams remain in a good state of preservation for up to 3 months at temperatures of 0 to 6 C. Thus, it would appear that shucked soft-shelled clams may be maintained for significantly longer periods in refrigerated storage than haddock fillets when the same radiation treatments are applied to each product. Clostridia levels in both products were relatively low initially, and were reduced significantly by the gamma rays at the doses studied. Moreover, those clostridia that survived the radiation treatments were found to remain at safe, low levels during the various periods in refrigerated storage employed for these products, a very encouraging result from the public health, as well as commercial, standpoint.
Preparation of Optically Active γ- and δ-Lactones by Microbiological Reduction of the Corresponding Keto Acids
Authors: Muys G. Tuynenburg , Van Der Ven B. , De Jonge A. P.
Published: December 2020

It was found, by means of simple screening methods, that several yeasts (
Saccharomyces
and
Candida
), molds (
Cladosporium
), and bacteria (
Sarcina
) are able to reduce keto acids to hydroxy acids, which are easily converted into lactones. Chemical analysis showed that some of the microorganisms (
Saccharomyces and Candida
) produce dextrorotatory lactones and others (
Cladosporium
and
Sarcina
) produce levorotatory lactones. High yields of dextrorotatory (both γ- and δ-lactones) were obtained by using
Saccharomyces cerevisiae
. The physical properties of the carefully distilled lactones obtained indicated high purity and high optical purity.
Inactivation of the Radiation-Resistant Spoilage Bacterium
Micrococcus radiodurans
Authors: Duggan D. E. , Anderson A. W. , Elliker P. R.
Published: December 2020

The R
1
strain of
Micrococcus radiodurans
, previously determined to be more resistant than three other strains exposed to gamma radiation, was studied further to determine the influence of certain environmental factors on resistance to radiation inactivation. The frozen state offered insignificant protection to the organisms irradiated in raw puréed beef. Resistance was reduced by higher menstruum temperatures (40 and 50 C) during irradiation. Preirradiation heat treatment was found to lower resistance to subsequent irradiation. When the cells were irradiated in buffer at pH 5, 7, or 9, no differences in resistance were noted. Cell suspensions in buffer were protected to some extent by cysteine but not by thioglycolate. Ascorbate enhanced radiation inactivation.
Growth of
Chlorella pyrenoidosa
in Recycled Medium
Authors: Leone Donald E.
Published: December 2020

Bench-scale studies with
Chlorella pyrenoidosa
7-11-05 were conducted in a 4-liter culture vessel with a used and recycled medium. Algal cultures were maintained for periods of several weeks by supplementing the nutrient medium with minimal amounts of certain salts. An algal strain was maintained for a period of up to 72 days with a supplemented recycled medium. No inhibition was observed as the result of any autotoxic materials. Rather dense cultures were maintained in the presence of high bacterial populations.
Influence of Sodium Hexametaphosphate on Selected Bacteria
Authors: Post F. J. , Krishnamurty G. B. , Flanagan M. D.
Published: December 2020

Sodium hexametaphosphate (HEX), the solvent of calcium alginate wool used in swabbing inanimate surfaces was studied relative to its effect on various bacterial populations, both pure cultures and wild. It was found that bacteria in wild populations were greatly inhibited, and that a percentage reduction of count was directly related to concentration of HEX. Most gram-positive bacteria were prevented from growing on a medium containing 0.1% HEX. This, or a higher concentration, occurred in the final medium when the method recommended in
Standard Methods for the Examination of Dairy Products
was followed. Growth of
Sarcina lutea
occurred on media with higher concentrations than that of inhibition (0.05%), if MgSO
4
·7H
2
O was incorporated in the medium. Gram-negative bacteria were capable of growing in higher concentrations, even up to 10% HEX. A large percentage of the cells of some strains (represented by
Pseudomonas fluorescens
) were lysed on contact with HEX. Lysis could be prevented by the addition of NaCl or MgSO
4
·7H
2
O. The evidence presented suggests that HEX, a phosphate-glass water-softening sequestrant, interferes with divalent cation metabolism, notably magnesium ion, and possibly others, producing cell division inhibition and loss of cell-wall integrity. The mechanism of action was not elucidated.
Enzymes Released from
Escherichia coli
With the Aid of a Servall Cell Fractionator
Authors: Duerre John A. , Ribi Edgar
Published: December 2020

The release and stability of the enzymes
S
-adenosylhomocysteine nucleosidase, lysine decarboxylase, arginine decarboxylase, glutamic decarboxylase, formic hydrogenlyase, formic oxidase, and glucose oxidase from
Escherichia coli
during disruption of the organisms in a Servall-Ribi refrigerated cell fractionator were examined. With the possible exception of arginine decarboxylase, maximal activity was retained by all the enzymes reported here when the cell suspensions were processed at pressures necessary for rupture of all the organisms (15,000 to 25,000 psi). Considerable variation in the stability of different enzymes liberated by disruption at higher pressures (45,000 to 55,000 psi) was observed. It is reasonable to assume that mechanical forces rather than effects of temperature are responsible for inactivation of these enzymes.
Staphylococcal Growth and Enterotoxin Production in Meat
Authors: Casman E. P. , McCoy D. W. , Brandly P. J.
Published: December 2020

Preliminary attempts were made to explain the association of staphylococcal food poisoning with cooked rather than uncooked meats. The abilities of various meats to support the growth of an enterotoxigenic staphylococcus, and the production of enterotoxin A, were determined. The production of enterotoxin was detected by means of serological procedures. Little or no growth was obtained when the inoculum was mixed with raw ground beef. When the surfaces of raw and cooked meats were inoculated, however, good growth was obtained with the production of enterotoxin.
Food Microorganisms Influencing the Growth of
Staphylococcus aureus
Authors: Graves R. R. , Frazier W. C.
Published: December 2020

Some 870 cultures of predominating micro-organisms were isolated from market samples of hamburger, fresh pork sausage, fresh fish fillets, stewing beef, frozen chicken pot pie, frozen corn, frozen peas, and pasteurized and raw milk, before and after storage at different temperatures. The isolates were screened for their ability to influence the growth of
Staphylococcus aureus
strain 196E by means of spot-plate tests on APT and nutrient agars at 25 C. The 438 cultures that influenced the growth of
S. aureus
were retested on spot plates at 15, 30, and 42 C. After elimination of replicates, the 143 remaining cultures were classified into species, genera, or groups, and 14 different cultures were tested for their influence on the growth of
S. aureus
in APT broth at 25 C. Over half of the effective cultures inhibited
S. aureus
and less than half were stimulatory. Pork sausage had the highest proportion of inhibitory cultures, and stewing beef had the lowest. APT agar was better than nutrient agar for screening, and incubation at 15 C gave more effector organisms than at 30 and 42 C. Most of the lactic acid bacteria were inhibitory, but other groups of bacteria contained more stimulatory cultures than inhibitory ones. The three
Escherichia coli
cultures were stimulatory, but most other
Escherichia
cultures were inhibitory.
Aerobacter
and
Paracolobactrum
isolates were mostly stimulatory. Cultures of other kinds of bacteria were more or less evenly distributed between inhibitory ones and stimulatory ones. Genera containing mostly inhibitory bacteria were
Streptococcus, Leuconostoc
, and
Lactobacillus
. Inhibitory species were
E. freundii
and
E. intermedia
. Tests with
S. aureus
in broth indicated that all cultures inhibitory according to spot plates were inhibitory in broth, but stimulation on spot plates did not always indicate the same phenomenon in broth.
Killing of Chlorine-Resistant Bacteria by Chlorine-Bromine Solutions
Authors: Farkas-Himsley H.
Published: December 2020

The disinfective power of chlorine, bromine, and mixtures of chlorine and bromine at different ratios was compared. The influence of pH was also studied. The experiments were carried out in “purified” water and in natural waters of swimming pools, river, and sea. In the presence of high amounts of nitrogenous growth-promoting material (at neutral pH), bromine was more effective than chlorine; in waters containing low amounts of nitrogenous growth-promoting material, chlorine was found superior. Mixtures of chlorine and bromine at various ratios were found to increase in effectiveness inversely to the percentage of hypobromite generated, down to 10 or 5%. Such effectiveness was found at pH levels of 5.4 to 8.6 in both purified and natural water containing high and low amounts of nitrogenous growth-promoting material. Therefore, the above mixtures seem of practical value for the disinfection of various natural waters.
Escherichia coli
isolated in the presence of chlorine, either from swimming pools or after deliberate exposure to the halogen, were shown to be chlorine-resistant mutants. Their resistance was maintained for at least nine passages in the absence of the disinfectant, which accounts for the number of passages tested. Chlorine-resistant mutants were not affected by bromine alone but did show a marked sensitivity to low concentrations of bromine active in the presence of chlorine. This was achieved by admixing small amounts of bromide to hypochlorite. A hypothetical model is presented to explain the synergistic sequential block by the two disinfectants. Some chlorine-resistant mutants were found to have changed into relatively slow-growing organisms with a changed phase-sensitivity pattern.
Bioelectrochemical Energy Conversion
Authors: Berk Richard S. , Canfield James H.
Published: December 2020

The interaction between photosynthetic microorganisms and an inert electrode material was examined. Cathodic polarization values of platinum-bearing marine algae were obtained over a wide current-density range under both illumination and dark conditions. A potential shift of 0.6 v in the cathodic direction occurred upon illumination at a current density of 4.3 μa/cm
2
. Similar photo-induced results, involving anodic polarization, were obtained by use of resting cells of
Rhodospirillum rubrum
supplemented with malate. Appropriate combinations of such bioelectrodes were used to assemble an electrochemical cell capable of light-dependent production of electrical energy.
Comparison of Two Methods for the Isolation of Salmonellae From Imported Foods
Authors: Taylor Welton I. , Hobbs Betty C. , Smith Muriel E.
Published: December 2020

Two methods for the detection of salmonellae in foods were compared in 179 imported meat and egg samples. The number of positive samples and replications, and the number of strains and kinds of serotypes were statistically comparable by both the direct enrichment method of the Food Hygiene Laboratory in England, and the pre-enrichment method devised for processed foods in the United States. Boneless frozen beef, veal, and horsemeat imported from five countries for consumption in England were found to have salmonellae present in 48 of 116 (41%) samples. Dried egg products imported from three countries were observed to have salmonellae in 10 of 63 (16%) samples. The high incidence of salmonellae isolated from imported foods illustrated the existence of an international health hazard resulting from the continuous introduction of exogenous strains of pathogenic microorganisms on a large scale.
Stimulation of Carotenogenesis by Microbial Cells
Authors: Ciegler A. , Pazola Z. , Hall H. H.
Published: December 2020

Spent mycelia of
Blakeslea trispora
recovered from a previous fermentation enhanced carotene production by mated cultures of the same organism. Peak yields of 107 to 142 mg of carotene per 100 ml of medium were achieved in 6 days. β-Carotene constituted 92% of the total carotenoids produced. The enhancing substance was found present in an aqueous extract of the mycelium. Part of its activity was due to an organic acid fraction. Other microbial cells, molds, yeasts, and bacteria were also capable of enhancing carotene production.
Coliforms Associated With Sugarcane Plants and Juices
Authors: Duncan Charles L. , Colmer Arthur R.
Published: December 2020

A study of the coliforms found on sugarcane plants throughout the growing season indicated that members of the genus
Aerobacter
comprise a part of the epiphytic microflora. When quantitative determinations were made of the coliforms by means of the most probable number technique, no completed tests were obtained on young sugarcane plants during the test period of February through May; however,
Paracolobactrum aerogenoides
was isolated frequently. Nine different IMViC types of coliforms were identified among the 198 isolates chosen for study. The predominating coliform found at the top, middle, and bottom portions of the sugarcane plants was
A. cloacae
, but the type predominating in leaf-sheath water was
A. aerogenes
. Only once was
Escherichia coli
found associated with the plants at the high dilutions necessary for determining most probable numbers. The numbers of different coliforms occurring in sugarcane juice were generally divided equally among
A. aerogenes, A. cloacae
, and
E. coli
. More variety among the IMViC types seemed to occur on the cane plants than in the leaf-sheath water or the cane juice in the mill.
Fusarium Growth Supported by Hydrocarbons
Authors: Flippin R. S. , Smith Christine , Mickelson M. N.
Published: December 2020

In studies of the microflora associated with fuel storage tanks, a
Fusarium
species was isolated from No. 1 diesel fuel. The culture was identified as
F. moniliforme
Sheldon. Attempts were made to cultivate this organism with seven hydrocarbons of 99
+
mole per cent purity as the sole carbon source; growth of the fungal culture was supported only by
n
-decane and
n
-dodecane. A spore viability study of
F. moniliforme
in filter-sterilized diesel fuel with no free water showed that viability was retained for 9 months in this environment.
Description and Treatment of a
Pseudomonas
Infection in White Catfish
Authors: Meyer F. P. , Collar J. D.
Published: December 2020

A virulent organism of the genus
Pseudomonas
was isolated from the white catfish,
Ictalurus catus
. The bacterium was pathogenic to all species of fish tested. Symptoms of the disease, physiological characteristics of the pathogen, and treatment methods are presented. Kanamycin injected intraperitoneally or oxytetracycline used as a feed additive was effective in controlling the disease. The growth and biochemical characteristics do not fit any description in
Bergey's Manual
, but the organism appears to be closely related to
P. fluorescens
.
Effect of Water Extracts of Carob Pods, Tannic Acid, and Their Derivatives on the Morphology and Growth of Microorganisms
Authors: Henis Y. , Tagari H. , Volcani R.
Published: December 2020

The effect of aqueous extracts of carob (
Ceratonia siliqua
) pods, gallotannic acid, gallic acid, and catechol on several microorganisms was studied. Carob pod extract and tannic acid showed a strong antimicrobial activity toward some cellulolytic bacteria. On the basis of tannin content, to which antimicrobial effect was related, carob pod extracts inhibited
Cellvibrio fulvus
and
Clostridium cellulosolvens
at 15 μg/ml,
Sporocytophaga myxococcoides
at 45 μg/ml, and
Bacillus subtilis
at 75 μg/ml. The inhibiting concentrations for tannic acid were found to be 12, 10, 45, and 30 μg/ml, respectively. Gallic acid and catechol were much less effective. Tannic acid and the tannin fraction of carob extract exerted both bacteriostatic and bactericidal effects on
C. fulvus
. Respiration of
C. fulvus
in the presence of bactericidal concentrations of tannic acid or tannin fraction of carob extract was inhibited less than 30%. A partial formation of “protoplasts” by
C. fulvus
was obtained after 2 hr of incubation in a growth medium to which 20% sucrose, 0.15% MgSO
4
·7H
2
O, and 10 to 50 μg/ml of tannic acid or 500μg/ml of penicillin, or both, had been added. Tannic acid and the tannin fraction of carob extract protected
C. fulvus
from metabolic lysis in sucrose solution. Although the growth of other microorganisms tested was only slightly affected, the morphology of some of them was drastically changed in the presence of subinhibitory concentrations of carob pod extracts of tannic acid. It is suggested that the site of action of tannins on sensitive microorganisms is primarily the cell envelope.
Erythritol Production by a Yeastlike Fungus
Authors: Hajny G. J. , Smith J. H. , Garver J. C.
Published: December 2020

A yeastlike fungus, probably belonging to the genus
Torula
, was isolated from fresh pollen and was shown to produce erythritol in yields of 35 to 40% of the sugar utilized. The ability to produce erythritol is an inherent characteristic of the isolate, but unfavorable fermentation conditions can lead to the production of glycerol at the expense of erythritol. By the use of a synthetic medium, it was shown that the concentrations of both nitrogen and phosphorous in the medium must be closely controlled to obtain satisfactory erythritol yields.
Response of
Clostridium perfringens
Spores and Vegetative Cells to Temperature Variation
Authors: Canada James C. , Strong Dorothy H. , Scott Lelia G.
Published: December 2020

The vegetative cells and spores of four strains of
Clostridium perfringens
were examined to determine the effect of lowered and elevated temperatures. Spores were produced by following the method of Ellner, and vegetative cells were obtained from thioglycolate cultures. After exposure to freezing or refrigeration temperatures (-17.7 and 7.1 C, respectively), only small numbers of the vegetative cells were recovered. After similar treatment, 16 to 58% of the spores were recovered. Essentially no vegetative cells and few spores survived holding at 80 C for 10 min. Although all strains were isolated from food, only one strain of the four studied had its origin in a food-poisoning outbreak, and it had been carried on laboratory media for approximately 10 years.
Bacteriology of Spoilage of Fish Muscle
Authors: Adams R. , Farber L. , Lerke P.
Published: December 2020

A test medium consisting of a sterile raw press juice from fish muscle was used to determine the incidence of spoilage bacteria on stored fillets of English sole (
Parophrys vetulus
). The initial load of spoilers was shown to be consistently below 10%. This percentage rose but slightly toward the middle of the spoilage runs, and actually declined when spoilage was most apparent both organoleptically and chemically. Further evidence implicating the
Pseudomonas
and
Achromobacter
groups in the spoilage of fresh fish is presented.
Procurement and Maintenance of Germ-Free Swine for Microbiological Investigations
Authors: Meyer R. C. , Bohl E. H. , Kohler E. M.
Published: December 2020

Germ-free swine were routinely procured by both hysterectomy and hysterotomy (Caesarian section). By means of light-weight portable equipment, piglets could be obtained and transported to the laboratory (without contamination) over distances in excess of 100 miles. The isolators employed in rearing were constructed of stainless steel and flexible plastic film. At weekly intervals, fecal swabs and waste from the floor of the isolator were cultured on blood-agar and in thioglycolate broth, as well as being examined microscopically for the presence of bacteria, yeast, and fungi. The presence of pleuropneumonia-like organisms (PPLO) and viruses in such material was not demonstrable, either by the use of enriched PPLO media or primary porcine-kidney cell cultures. Tissues, body fluids, and cecal contents of piglets sacrificed specifically for microbiological examination were also negative for PPLO, viruses, bacteria, yeast, and fungi. Prenatal infestations by ascarids were not observed. Nutritional problems related to rearing of germ-free piglets, such as hypoglycemia, were not encountered, and the use of an autoclaved commercial sow's milk replacer proved quite satisfactory. The temperature to which piglets were subjected during the first few days of life, however, was very important. The isolator design and application of gnotobiotic techniques to the procurement and rearing of a large germ-free animal such as the pig proved feasible and less difficult than anticipated.
Cellular Lipids of a
Nocardia
Grown on Propane and
n
-Butane
Authors: Davis J. B.
Published: December 2020

Lipid fractions of propane- and
n
-butane-grown nocardial cells each contain a chloroform-soluble, ether-insoluble polymer not observed previously in liquid
n
-alkane-grown cells. The polymer in propane-grown cells is poly-β-hydroxybutyrate. The polymer in
n
-butane-grown cells apparently contains unsaturation in the molecule, and is identified tentatively as a co-polymer of β-hydroxybutyric and β-hydroxybutenoic (specifically 3-hydroxy 2-butenoic) acids. The other major component of the lipid fraction consists of triglycerides containing principally palmitic and stearic acids. There seems to be little qualitative distinction in the glycerides of propane- or
n
-butane-grown cells. Oxidative assimilation of
n
-butane is described.
Technical Considerations in the Preparation of Fluorescent-Antibody Conjugates
Authors: Lewis Vester J. , Jones Wallis L. , Brooks John B. , Cherry William B.
Published: December 2020

A comparison was made of (NH
4
)
2
SO
4
, HCl, ethodin, and ethanol for fractionation of rabbit antiserum prior to conjugation with fluorescein isothiocyanate. Fractionation with the salt was found to be the method of choice from the standpoints of simplicity and recovery of antibody effective in conjugates prepared from the fractions. Effects of pH, temperature, dye-protein ratio, and molarity and type of buffer upon conjugation were studied. These technical factors were adjusted to produce conjugates for
Corynebacterium diphtheriae
which possessed higher specific titers than did reagents obtained by previously employed techniques.
Effect of Absence of Ciliate Protozoa From the Rumen on Microbial Activity and Growth of Lambs
Authors: Akkada A. R. Abou , El-Shazly K.
Published: December 2020

A survey of the components of the rumen ciliate population in a series of adult sheep, raised in the Faculty of Agriculture, University of Alexandria, has shown that a mixture of
Entodinium, Isotricha, Ophryoscolex, Diplodinium
, and
Polyplastron
species was found in the rumen contents of Egyptian sheep; no
Epidinium
and a negligible number of
Dasytricha ruminantium
were also observed. The microbial population, reducing sugars, ammonia, volatile fatty acids (VFA) production, and growth rate of 14 lambs inoculated with whole rumen contents from a mature sheep were compared over a 6-month period with those of 13 lambs maintained under the same conditions, except that they were strictly isolated from other ruminants. Certain large oval organisms and large numbers of flagellates and
Oscillospira
were frequently observed in the rumen contents of the isolated lambs. The reducing sugars, ammonia, and VFA levels, measured before and at intervals after feeding, in the inoculated lambs showed a pronounced rise above the values found in the ciliate-free animals. The propionic acid-acetic acid ratio in the rumen contents of the faunated lambs was considerably higher than in the nonfaunated controls. The inoculated lambs grew faster than the isolated lambs. Differences in weight gain which ranged from 15 to 17% were statistically significant. The inoculated animals impressed the observers by their good appearance which was superior to that of the ciliate-free lambs. It was, therefore, concluded that the rumen ciliate protozoa are essential for the metabolism and growth of young lambs.
Effect of Phenol on
Bacillus subtilis
Spores at Elevated Temperatures
Authors: Russell A. D. , Loosemore Muriel
Published: December 2020

The nature of the recovery medium is shown to influence the number of
Bacillus subtilis
spores which, after exposure to 2.5 or 5% phenol at high temperatures, can produce a visible colony. Higher survivor counts were obtained in nutrient agar containing L-alanine and D-glucose than in plain nutrient agar.
Microbial Ecology of Activated Sludge
Authors: Dias F. F. , Bhat J. V.
Published: December 2020

Over 300 bacterial strains were isolated from seven samples of activated sludge by plating on sewage agar. Gram-negative bacteria of the genera
Zoogloea
and
Comamonas
predominated. Many isolates (51%) showed sudanophilic inclusions of poly-β-hydroxybutyric acid, whereas 34% accumulated iodophilic material on media containing starch. A large number required either vitamins or amino acids, or both, for growth. None of the isolates tested for their ability to bring about changes in autoclaved sewage produced an effluent comparable in quality to the activated sludge control, although the
Zoogloea
did produce activated sludgelike flocs. A study of 150 bacterial strains isolated from raw sewage revealed that they differed from the sludge isolates in several respects. Coliforms, which constitute nearly a quarter of the sewage isolates, were rarely encountered in sludge.
Manganese Requirement for Sporulation and Other Secondary Biosynthetic Processes of
Bacillus
Authors: Weinberg Eugene D.
Published: December 2020

Concentrations of manganese, considerably in excess of the quantity required for normal vegetative growth, are needed by
Bacillus
for (i) synthesis of such secondary metabolites and structures as antibiotics, D-glutamyl peptide, endospores, bacteriophage, and protective antigen; and (ii) longevity of vegetative cell cultures. No other biologically active element can substitute for manganese, and no secondary biosynthetic process of
Bacillus
has been found in which the requirement for manganese is absent. In the present study, manganese could induce sporulation of
B. megaterium
even when added to synthetic broth cultures as late as 100 hr after inoculation. When sub-bactericidal concentrations of various biologically active trace elements were supplied within 2 hr of manganese addition, suppression of spore formation occurred in cultures exposed to elements of group VI (chromium, molybdenum, tungsten, selenium, tellurium) and one of group VIII (nickel); of the six interfering elements, selenium and nickel were most potent.
Detection of
Salmonella
in Eggs and Egg Products With Fluorescent Antibody
Authors: Haglund John R. , Ayres John C. , Paton Alan M. , Kraft Allen A. , Quinn Loyd Y.
Published: December 2020

Organisms of the genus
Salmonella
are detected in eggs and egg products within 24 hr in the presence of Pseudomonadaceae and other Enterobacteriaceae by combining selective cultural methods with fluorescent-antibody techniques. These techniques are specific for
Salmonella
when H antibodies are used. Absorption techniques are necessary before the O antibodies give specific reactions for
Salmonella
. No cross-reactions appear when H antiserum is used. Absorption and interference techniques indicate the test is specific for
Salmonella
.
Medium for the Quantitative Recovery of Members of the Genera
Pasteurella
and
Brucella
Authors: Cabelli Victor J. , Levin Morris A.
Published: December 2020

A modification of peptic digest-starch (PDS) medium for the quantitative enumeration of
Pasteurella tularensis
is described. This modification (PDM), in which the concentration of L-cysteine was decreased and in which Brilliant Green was substituted for the penicillin added to the original medium, was evaluated and was found satisfactory for the recovery of
P. tularensis, P. pestis
, and members of the genus
Brucella
, from freshly harvested and stored cultures as well as aerosolized organisms produced therefrom. With weakly virulent strains of
P. tularensis
, such as the Jap 4 and LV strains, it was found that PDM was not adequate.