bluuebunny/crossref_metadata_2025 huggingface dataset:
Classification of Friction and Wear State of Wind Turbine Gearboxes Using Decision Tree and Random Forest Algorithms
Authors: Pang Jinshan , Chen Yuming , He Shizhong , Qiu Huihe , Wu Chili , Mao Lingbo
Published: December 2020

Based on oil monitoring technology to collect friction and wear parameters, the failure modes of key friction pairs in wind turbine gearboxes can be evaluated and classified. However, the collected data of failures caused by friction and wear are generally small, which limits the application of machine learning in the monitoring or evaluation of the critical friction pairs of wind turbine gearboxes. To verify the feasibility of machine learning in this application, algorithms including decision tree (DT), random forest (RF), k-nearest neighbors (k-NN), and support vector machine (SVM) are implemented, in the context of a small dataset of 424 samples of normal, adhesive, fatigue, and cutting wear for outcome classification. Compared with k-NN and SVM, DT and RF perform better on both training and test samples. The two models identified the key factors and their quantified values associated with failure state, including ferromagnetic particles, viscosity, iron content, and external hard particle silicon. The classifiers developed in this work classified failure state with an average accuracy of 96%, thus offering an accurate decision support tool for classification and evaluation of the friction pair wear state of wind turbine gearboxes.
Heat Transfer Coefficient Distribution on Oil Injection Cooled Gears: Experimental Method, Uncertainty, and Results
Authors: von Plehwe Felix C. , Schwitzke Corina , Bauer Hans-Jörg
Published: December 2020

To design gearboxes with very high power densities, an effective means of cooling the gears and knowledge of the achievable heat transfer coefficients are necessary. In this paper, a method to measure heat transfer coefficients for oil injection cooled gears is presented. Contrary to other experimental investigations, a single hollow spur gear is used. To measure heat transfer coefficients, a temperature gradient between the gear and the hot oil needs to be induced. This is achieved by injecting hot oil at realistic temperatures and cooling the inside diameter of the gear. This enables the measurement of heat transfer coefficients in absence of any dissipative or frictional losses, decreasing the measurement uncertainty. In addition, the novel method yields spatially resolved HTC data. The uncertainty of the method is assessed using Monte Carlo simulations. Experimental results for various operating conditions are presented. For all investigated oil flowrates, the same characteristic behavior of the average heat transfer coefficient versus rotational speed was observed. This observation can be explained by using a kinematic model of the oil jet. The geometry of the gear and the cooling arrangement and the spatially resolved HTC data presented in this paper provide a complete basis for the validation of numerical simulations.
Crystal aggregates record the pre-eruptive flow field in the volcanic conduit at Kīlauea, Hawaii
Authors: DiBenedetto Michelle , Qin Zhipeng , Suckale Jenny
Published: December 2020

Crystal aggregates that erupted at Kilauea volcano were formed in the presence of waves inside the conduit before eruption.
A cytokine to remember me by
Authors: Halawi Aya , Griffin Gabriel K.
Published: December 2020

Cohesin restrains cytokine-induced transcriptional memory.
Reproducibility of the Most Probable Numbers Technique for Determining the Sanitary Quality of Clams
Authors: Lear Donald W.
Published: December 2020

The reproducibility of most probable numbers results in the bacteriological examination of clam meats, using the tentatively recommended procedure, is less than has been indicated in use with water analysis. Entrapped air bubbles in ground clam meats contribute to the variability of results by (i) lowering the density of the sample material, producing inaccurate aliquots for inocula, and (ii) interfering with the attainment of homogeneity in the brei.
Species Differentiation of Group D Streptococci
Authors: Papavassiliou J.
Published: December 2020

Three hundred and fourteen strains of group D streptococci were studied by means of a number of tests. The majority of the strains were identified as
Streptococcus faecalis
(83 strains),
Streptococcus faecium
(131 strains), or
Streptococcus bovis
(32 strains). Several strains (47 or nearly 15%) either shared characteristics of two species or were completely atypical.
S. faecalis
and
S. bovis
were more easily identified than
S. faecium
, which is not sharply defined from the other species and could be subdivided into several fermentative types on the basis of fermentation of arabinose, mannitol, sorbitol, glycerol, and sucrose. The value of some characteristics in species identification is discussed. Growth in the presence of potassium tellurite 1:2,500 and in the presence of 6.5% NaCl and fermentation of arabinose, glycerol, and raffinose are very important tests for the identification of the three species. The reduction of tetrazolium salts, the reduction of litmus milk, and the fermentation of sorbitol may serve as complementary tests for the same purpose. For the differentiation of these three species the “pattern of reactions” is more important than single tests.
Production Model Press for the Preparation of Bacterial Cell Walls
Authors: Perrine T. D. , Ribi E. , Maki W. , Miller B. , Oertli E.
Published: December 2020

A modification of the apparatus previously described permits the preparation of cell walls in quantity. This consists of a heavy duty, double-acting hydraulic press with motor-driven pump, and a superstrength alloy steel pressure cell which is corrosion resistant. Liquid cooling of the jet is substituted for the previously used gas cooling to minimize aerosol formation and to facilitate subsequent treatment of the products. The device produces cell walls of excellent quality in good yield. The pressure cell has been used satisfactorily up to about 60,000 psi. Design details are given.
Nonlethal Freezing Injury to Metabolism and Motility of
Pseudomonas fluorescens
and
Escherichia coli
Authors: Arpai J.
Published: December 2020

Some specific effects of the conditions of freezing on death and metabolic injury of a psychrophilic and a mesophilic species of bacteria were investigated, with particular respect to changes in motility. It was found that the extent of nonlethal metabolic freezing injury and the changes in motility are apparently correlated and are affected by the time and temperature of storage and the nature and pH of the suspending fluid. There were significant differences between the resistance to cold of the test organisms, the mesophilic being the more sensitive. The motility of the psychrophilic
Pseudomonas fluorescens
decreased considerably less after low-temperature exposure than did that of the mesophilic
Escherichia coli
. The percentage of restoration in motility of the subcultures was lower after freezing in water than in other suspending fluids.
Bacteriological Examination of Unbottled Soft Drinks
Authors: Ramadan F. M. , Abd-Elnaby H. A.
Published: December 2020

A study of 300 samples, representing 14 different unbottled drinks, indicated that there are three vitally important criteria pertaining to their bacteriological examination. First, the total viable counts may be better accomplished by the pour-plate method, using enriched media, with incubation at either 30 or 37 C. Second, a comparative study of the coliaerogenes group and the enterococci as indices of pollution unquestionably favors the latter as the reliable indicator, owing to false interpretations of the presumptive test and to lack of accurate definition of fecal and nonfecal coliforms recovered from positive cases. The use of enterococci, however, did not provide as reliable an indicator as the pour-plate method. Third, the results with enterococci, in defining the probable source of pollution, are more precise. Experiments judiciously selected and simultaneously conducted revealed that the heat and heat-tellurite resistance tests, and the tetrazolium-reduction test, matched in relating 98.9% of available enterococci to an animal source. Negligible but vital discrepancies were obtained with the two odd strains which qualified as human-derived according to the heat and heat-tellurite resistance tests. The differential criterion of Skadhauge and Barnes, based on the failure of animal-derived enterococci to grow in the presence of a low concentration of potassium tellurite, did not apply to the other two methods, since 99.5% of the recovered strains were found tolerant to the specified tellurite concentration.
Absorption and Transport of Fluorescent Brighteners by Microorganisms
Authors: Darken Marjorie A.
Published: December 2020

The absorption of brighteners by living cells and their transport to subsequent growth is described. Brighteners are highly fluorescent, ultraviolet-absorbing compounds which appear to be essentially nontoxic, stable biological markers. They have been effectively absorbed by growing cultures of bacteria, yeasts, actinomycetes, and higher fungi, with active growth centers evidencing the greatest flourescence.
Formation of Extracellular Sphingolipids by Microorganisms
Authors: Maister Hanns G. , Rogovin S. Peter , Stodola Frank H. , Wickerham Lynferd J.
Published: December 2020

Tetraacetylphytosphingosine (TAPS) formation by the F-60-10 mating type strain of the yeast
Hansenula ciferrii
, previously observed on agar plates, has been shown to take place in submerged cultures. The optimal conditions for TAPS formation, and the correlation of TAPS production and sugar utilization under aerobic conditions, were studied in 10-liter fermentors. For each gram of glucose consumed, 5 mg of TAPS were formed; for each gram of yeast solids produced, 15 mg of TAPS were synthesized. A 750-liter pilot-plant run yielded 175 g of crude TAPS, which were obtained by hexane extraction of centrifuged yeast cells.
Lipid Metabolism of Rumen Ciliates and Bacteria
Authors: Gutierrez J. , Williams P. P. , Davis R. E. , Warwick E. J.
Published: December 2020

Washed suspensions of the ruminal ciliates,
Isotricha prostoma
and
Entodinium simplex
, concentrated C
14
-labeled oleic, palmitic, stearic, and linoleic acids within the cells during short incubation periods. Radioautographs demonstrated that oleic acid-1-C
14
was hydrogenated to stearic acid by
I. prostoma
, and Warburg manometric data showed that the sodium salts of oleic, valeric, caproic, and acetic acids, and methyl myristate, methyl laurate, and the triglyceride tributyrin stimulated fermentation of
I. prostoma
. The total lipid and free fatty acid contents of
I. prostoma
were determined.
Distinctive Properties of β-Glucosidases and Related Enzymes Derived from a Commercial
Aspergillus niger
Cellulase
Authors: King K. W. , Smibert R. M.
Published: December 2020

Eight highly purified β-glucosidases from
Aspergillus niger
were compared enzymatically, chemically, and immunologically. Ultraviolet spectra, pH-activity responses, substrate specificities, thermal stabilities, kinetic changes in the viscosity of substrate, Michaelis-Menten parameters, adsorption characteristics on cellulose, and exclusion characteristics on dextran gels were determined. The data indicate that the several components represent distinctly different enzymes in terms of mode of attack on substrate. The concept of partial denaturation of a single enzyme precursor is unable to explain the heterogeneity observed. Comparison of the effect of pH on hydrolysis of carboxymethylcellulose and cellohexaose suggests that a negative charge center on the substrate has a pronounced inhibitory effect on the enzymes.
Accuracy of a Plant-Infection Technique for Counting Populations of
Rhizobium trifolii
Authors: Brockwell J.
Published: December 2020

A “plant-infection” technique for identification and estimation of populations of
Rhizobium
is described and compared with petri dish colony counts of the same bacterial populations. Provided that bacterial suspensions are agitated thoroughly, dilutions made at 4 C, and test plants grown on agar, the plant-infection technique is an accurate method of estimating
R. trifolii
in pure culture or when added to soil. The results are discussed in relation to previous investigations of the subject. Tables are presented which, when applied to the distribution of positive (nodulated) test plants in either fivefold or tenfold dilution series, permit calculation of most probable numbers, and confidence limits are stated.
Production of Hydrogen Sulfide by Streptomycetes and Methods for its Detection
Authors: Küster E. , Williams S. T.
Published: December 2020

The ability of streptomycetes to produce hydrogen sulfide is generally used for taxonomic purposes. It was found that the previously used method, the blackening of Peptone Iron Agar, does not clearly indicate formation of hydrogen sulfide. It was shown that the blackening of a lead acetate strip is the most accurate indicator for H
2
S-producing streptomycetes. A great variety of organic and inorganic sulfur compounds were examined and compared, and the choice of the most suitable sulfur source and method for the detection of hydrogen sulfide is discussed.
Microbial Hydroxylation of Indole Alkaloids
Authors: Hartman R. E. , Krause E. F. , Andres W. W. , Patterson E. L.
Published: December 2020

The hydroxylation of the indole-type alkaloids, yohimbine, α-yohimbine, β-yohimbine, and corynanthine, was achieved with several genera of higher fungi and species of
Streptomyces
. Microorganisms were found which monohydroxylated these compounds in three different positions. The site of hydroxylation was strain-specific for two strains of
Cunninghamella echinulata
and
C. bainieri
.
Disinfection of Aerosolized Pathogenic Fungi on Laboratory Surfaces
Authors: Kruse Richard H. , Green Theron D. , Chambers Richard C. , Jones Marian W.
Published: December 2020

The effect of several fungicides on laboratory surfaces contaminated with the culture (spore) phase of aerosolized
Blastomyces dermatitidis, Coccidioides immitis
, and
Histoplasma capsulatum
was ascertained. The culture (spore) phase was more resistant to the action of the fungicides than was the tissue (yeast) phase. The addition of a wetting agent increased the efficiency of several fungicides. The time required for disinfection with a given concentration of fungicide, or the concentration required to disinfect within a given time, can be determined by interpolating the plotted graphs.
Comparison of Several Selective Media for Isolation and Differentiation of Coagulase-Positive Strains of
Staphylococcus aureus
Authors: McDivitt Maxine E. , Topp Eleanor B.
Published: December 2020

Six coagulase-positive strains of
Staphylococcus aureus
which had been cultivated in Brain Heart Infusion broth, milk, and brine were plated on seven isolation media. A significant difference in the growth patterns of the individual strains was found as well as a significant effect resulting from the previous cultivation history before plating. Brine and, to a lesser extent, milk were found to reduce maximal cell concentrations attained, but strains grown in brine and milk showed greater ability to withstand the selective action of the isolation media. Fibrinogen applied to the surface of five of the media allowed the formation of characteristic halos by coagulase-positive strains of
S. aureus
. Only half of the strains studied produced a zone of precipitation on SM110-Egg Yolk agar. The isolation medium containing cycloheximide and a high level of polymxin B was most inhibitory to the organisms.
Freezing-Out Technique Applied to the Concentration of Biologically Active Materials
Authors: Wilson T. E. , Evans D. J. , Theriot Mary L.
Published: December 2020

When applied to a dilute solution of folic acid and glucose, a freezing-out (with agitation) technique was shown to be an effective method of achieving a 20-fold reduction in volume with a loss of 10% of the active material being concentrated. Concentration of a stimulatory factor for
Lactobacillus casei
produced by
Candida albicans
in a complex medium was limited by the total solute concentration. Salts in the medium were concentrated to levels inhibitory for
L. casei
. The process is not selective and all solutes are concentrated.
Sequential Substrate Removal in Response to Qualitative Shock Loading of Activated Sludge Systems
Authors: Gaudy A. F. , Komolrit K. , Gaudy E. T.
Published: December 2020

Heterogeneous populations acclimated to sorbitol or mannitol were subjected to shock loading with glucose during growth on the sugar alcohol. Under these severe shock-loading conditions, glucose caused immediate cessation of sorbitol or mannitol removal. Metabolism of these compounds was renewed subsequent to glucose exhaustion. Under similar shock-loading conditions, with the use of cells operationally defined as “old,” the sugar alcohols were removed concurrently with glucose. In the absence of a nitrogen source with old cells, the added glucose was removed slowly in the presence of sorbitol and not at all in the mannitol-acclimated system. These results indicate the potential variability in purification efficiency attributable to substrate interaction.
Gelatinase Activity by Marine Fungi
Authors: Pisano M. A. , Mihalik J. A. , Catalano G. R.
Published: December 2020

Gelatinase activity was detectable in the culture filtrates of 13 of 14 species of marine fungi tested. The fungi were grown under conditions of submerged culture in a medium consisting of corn meal, soybean meal, and CaCO
3
. The degree of enzymatic activity did not necessarily correlate with the amino nitrogen content of the filtrates. Eight of the filtrates contained measurable quantities of glutamic acid and alanine. Highest levels of gelatinase were obtained in the culture filtrates of
Halosphaeria mediosetigera
. Increasing the corn meal concentration of the medium resulted in even greater production of gelatinase by
H. mediosetigera
, whereas amino acid yields were enhanced by higher concentrations of soybean meal. Supplementation of the high corn meal medium with either a mineral mixture or distillers' solubles brought about a faster rate of production of gelatinase and, in the case of the distillers' solubles, a significantly higher level of enzyme, as well.
Abundant Microorganism in Soil
Authors: Casida L. E.
Published: December 2020

The presence in soil of large numbers of a catalase-negative, microaerophilic, coccoid microorganism was demonstrated. Use of media of high nutrient value, without incorporation of inhibitors, and growth in the absence of antagonistic microorganisms were utilized to isolate this organism from soil dilutions greater than those providing growth by other means. The organism described does not grow on soil extract agars and is missed by conventional counting techniques for soil organisms. On the basis of morphological and growth characteristics, this organism appears to have at least some taxonomic relationships to the families Actinomycetaceae and Mycobacteriaceae. It is proposed that this organism makes up much of the coccoid microflora of soil as observed by light and ultraviolet fluorescence microscopy.
Enzymatic Production of
l
-Alanine by
Pseudomonas dacunhae
Authors: Chibata Ichiro , Kakimoto Toshio , Kato Jyoji
Published: December 2020

To establish an advantageous method for the production of
l
-alanine, a procedure was studied for converting
l
-aspartic acid to
l
-alanine by microbial
l
-aspartic β-decarboxylase. A number of organisms were screened to test their ability to form and accumulate alanine from aspartic acid.
Pseudomonas dacunhae
was selected as the most advantageous organism. With this organism, enzyme activity as high as 3,910 μliters of CO
2
per hr per ml of medium could be produced by shaking the culture at 30 C in the medium containing ammonium fumarate, sodium fumarate, corn steep liquor, peptone, and inorganic salts. For the enzymatic conversion of
l
-aspartic acid to
l
-alanine, the culture broth was employed as the enzyme source. A large amount of
l
-aspartic acid (as much as 40% of the broth) was converted stoichiometrically to alanine in 72 hr at 37 C. Furthermore, appropriate addition of a surface-active agent to the reaction mixture was found to be highly effective in shortening the time required for the conversion. Accumulated
l
-alanine was readily isolated in pure form by ordinary procedures with ion-exchange resins. Yields of isolated
l
-alanine of over 90% from
l
-aspartic acid were easily attainable.
Microbiology of Drycleaning
Authors: Banville Robert R. , McNeil Ethel
Published: December 2020

An appreciable number of bacteria on contaminated fabric survived modern drycleaning procedures. Various stages in the process, especially steam pressing, reduced the total number of bacteria, but viable organisms were found on certain areas of garments even after pressing. A significant number of bacteria were redeposited on clean fabric during the washing of ordinary soiled garments in drycleaning units. These bacteria included gram-positive cocci, diphtheroid bacilli, and gram-positive sporeformers. Gram-negative bacilli were seldom found, although some gram-negative bacilli survived drycleaning. The redeposited organisms apparently came mainly from other garments in the same loads, as few bacteria were isolated from the filtered solvent used for washing. The number of bacteria in the drycleaning washwheel was highest shortly after the beginning of the wash, and decreased, with the exchange of solvent in the wheel, to a low level at the end. Although it appears that in most cases several factors combine to reduce to a low level the numbers of bacteria on articles cleaned in a well-operated drycleaning plant, it would seem that under certain conditions pathogenic microorganisms could be disseminated by drycleaning.
Method for Measuring Diaminopimelic Acid in Total Rumen Contents and Its Application to the Estimation of Bacterial Growth
Authors: El-Shazly K. , Hungate R. E.
Published: December 2020

Diaminopimelic acid (DAP) was measured in rumen samples for which growth rate had previously been estimated from changes in fermentation capacity. The growth measurements by the two methods agreed within the experimental error. Agreement between the rate of bacterial growth (DAP) and total microbial growth (fermentation capacity) suggests that the protozoa also grow at about this rate.
Quantitative Studies on Fabrics as Disseminators of Viruses
Authors: Sidwell Robert W. , Dixon Glen J. , Mcneil Ethel
Published: December 2020

The persistence of vaccinia virus on wool (blanket and gabardine) and cotton (sheeting, terry cloth, and knit jersey) fabrics was studied. The fabrics were exposed to the virus by three methods: direct contact, aerosol, and virus-containing dust having a high content of textile fibers. Fabrics exposed to virus by each method were held in 35 and 78% relative humidities at 25 C. Virus was recovered for up to 14 weeks from wool fabrics exposed to virus and held in the low humidity. In contrast, virus persisted for shorter periods of time on the cotton fabrics. No virus was detected on terry cloth as early as 3 days after exposure to virus. The virus appeared to be less stable in the high humidity, and the method of exposure of the fabrics to virus apparently had an effect upon the persistence of the agent. On all fabrics, viral persistence was of sufficient duration to be of epidemiological significance.
Influence of Food Microorganisms on Staphylococcal Growth and Enterotoxin Production in Meat
Authors: McCoy D. W. , Faber J. E.
Published: December 2020

Forty-four microorganisms were studied for their influence on staphylococcal growth and enterotoxin production. Inhibition was found to be more common than stimulation. Two types of inhibition were observed: inhibition of staphylococcal growth, and inhibition of enterotoxin formation with no apparent effect on growth. By use of a plate test, 12 of the 44 food microorganisms were found to inhibit staphylococcal growth at 35 C. Of the 12, 3 also inhibited growth at 25 C. No significant differences in inhibition were observed with the 15 strains of enterotoxigenic staphylococci. In meat slurries, inhibition of staphylococcal growth was found to be greater at 25 C than at 35 C. Results on inhibition obtained from the plate test could not be correlated with the effect of the organisms in slurries. Environmental conditions were found to affect markedly the influence of food microorganisms on staphylococci. Of the 44 food microorganisms studied, only
Bacillus cereus
was observed to stimulate significantly staphylococcal growth and enterotoxin formation. Stimulation was more pronounced with
Staphylococcus aureus
196E than with other strains of enterotoxigenic staphylococci.
Bacillus megaterium
and
Brevibacterium linens
were inhibited by staphylococci. These organisms were completely inhibited when inoculated in mixed cultures with staphylococci. In pure cultures, good staphylococcal growth was found to be accompanied by enterotoxin production; however, in the presence of food microorganisms, good staphylococcal growth occurred without the formation of detectable levels of enterotoxin A.
Biochemical Alterations of Dermatophytes during Growth
Authors: Swanson R. , Stock J. J.
Published: December 2020

Alterations in the biochemical constituents of mycelia were studied during the growth, development, and starvation of
Microsporum quinckeanum
. On the basis of dry weight, growth of this dermatophyte could be divided into four phases: lag, log, stationary, and death. The percentage of total nitrogen, inorganic phosphorus, ribonucleic acid (RNA), and protein increased rapidly during the lag phase. The percentage of protein remained constant after the initial increase; however, inorganic phosphate and RNA decreased in older mycelia. Acid-soluble materials in the cells increased in concentration as the organism aged. Chitin was present in the spores at a much higher concentration than in the mycelia. The percentage of this compound decreased rapidly until the end of the lag phase. An increase and subsequent decrease in per cent chitin occurred during the log phase. Inorganic phosphorus in the mycelia increased from the value in the spore stage to a maximum in the early log phase, and then decreased rapidly during the remainder of the growth cycle. Compounds involved in protein synthesis increased rapidly during the lag phase of growth. Changes in chemical composition of the mold during starvation indicate that carbohydrate does not form the principal endogenous reserve of
M. quinckeanum
, whereas lipids may represent the primary reserve material.
Detection and Identification of Bacteria by Gas Chromatography
Authors: Henis Y. , Gould J. R. , Alexander M.
Published: December 2020

Ether extracts of cultures of 29 strains representing 6 species of
Bacillus
, and of individual strains of
Escherichia coli, Aerobacter aerogenes
, and
Pseudomonas aeruginosa
were examined in a gas chromatograph by use of flame ionization and electron capture detectors. Among the products detected were compounds with the chromatographic characteristics of acetic, propionic, and butyric acids, ethyl alcohol, diacetyl, acetoin, and 2,3-butanediol. The differences in peak areas of the various products formed by the bacteria were determined statistically for the chromatograms obtained with the two detectors, and the peaks were arranged in order of decreasing areas to yield a signature for each bacterial strain. Different signatures were obtained for the various genera and species and for strains of the same species.
B. licheniformis, B. subtilis
, and
A. aerogenes
formed significant quantities of a number of volatile compounds, and qualitative and quantitative differences between strains were noted. The electron capture detector was particularly sensitive to diacetyl and acetoin as well as to unknown compounds. By use of this detector, the presence of 5 pg of diacetyl and 20 pg of acetoin could be demonstrated. The quantity of acetoin detected in
B. subtilis
and
B. licheniformis
cultures was present in as little as 6.3 × 10
-3
μliters of medium.
Viral Depuration of the Northern Quahaug
Authors: Liu Oscar C. , Seraichekas Helen R. , Murphy Bert L.
Published: December 2020

A study was conducted to evaluate critically the feasibility of using the self-cleansing mechanism as a practical means to obtain virus-free shellfish. Two systems supplied with fresh running seawater, three strains of human enterovirus and the Northern quahaug, were used as working models. Preliminary experiments in the experimental system under arbitrarily selected conditions showed that depuration of poliovirus-polluted quahaugs could be achieved by the method used for the Eastern oyster. The factors affecting viral depuration studied so far included: (i) initial concentration of shellfish pollution; (ii) temperature of seawater; and (iii) salinity of seawater. It was shown that purification of the lightly polluted shellfish was achieved sooner than of the heavily polluted ones. The efficiency of viral depuration was roughly a function of the water temperature within the range tested (5 to 20 C). Reduction of salinity to 50 to 60% of the original level stopped this process completely, but 25% reduction in salinity did not affect significantly the rate of depuration. Preliminary study in the pilot system showed that viral depuration in the large tank appeared to be equally as efficient as that in the small experimental tanks under the particular conditions.
Survival of Poliovirus in Flowing Turbid Seawater Treated with Ultraviolet Light
Authors: Hill W. F. , Hamblet F. E. , Akin E. W.
Published: December 2020

The effectiveness of a model ultraviolet (UV) radiation unit for treating flowing turbid seawater contaminated with poliovirus was determined. At a turbidity of 70 ppm, the observed survival ratios ranged from 1.9 × 10
-3
(99.81% reduction) to 1.5 × 10
-4
(99.98% reduction) at flow rates ranging from 25 to 15 liters/min; no virus was recovered at flow rates of 10 and 5 liters/min. At a turbidity of 240 ppm, the observed survival ratios ranged from 3.2 × 10
-2
(96.80% reduction) to 2.1 × 10
-4
(99.98% reduction) at flow rates ranging from 25 to 5 liters/min. As expected, turbidity had an adverse influence on the effectiveness of UV radiation; however, by adjusting the flow rate of the seawater through the treatment unit, adequate disinfection was shown to be predictable.
Degradation of Pure Aflatoxins by
Tetrahymena pyriformis
Authors: Teunisson Dorothea J. , Robertson James A.
Published: December 2020

Tetrahymena pyriformis
W with nutrients, ca. 22 � 10
6
cells, decreased the concentration of aflatoxin B
1
58% in 24 hr and 67% in 48 hr. An unknown, bright-blue fluorescent substance was produced, with intensity about one-half that of the unchanged B
1
, with an

R
f

of 0.52 compared with 0.59 for B
1
and 0.55 for B
2
on a thin-layer chromatography plate, and with an ultraviolet spectrum showing maxima of 253, 261, and 328 mμ. In a separate assay, the cells with nutrients did not degrade pure G
1
. Starved, washed cells, ca. 11 � 10
6
, decreased the concentration of B
1
50% in 10 hr, 70% in 22 hr, and 75% in 30 hr, producing the same unknown component. Ethyl alcohol, 1.96% (v/v), decreased cell populations and size, but the cells remained actively motile in broth plus the alcohol for 96 hr. In 72 hr, neither toxin (ca. 2 ppm) in combination with ethyl alcohol had more inhibitory effect on cell numbers, with or without nutrients, than was produced by alcohol alone. Aflatoxin B
1
had no observed effect on the viability of the starved cells for 30 hr or on the nourished cells for 72 hr. There was no noticeable effect of G
1
on the starved cells in 30 hr or on the nourished cells in 48 hr. After 72 hr with G
1
plus nutrients, many of the cells were round with blisters, nonmotile, and apparently dead or dying.
Occurrence of an Inhibitor of Lactic Acid Bacteria in Green Olives
Authors: Fleming H. P. , Etchells J. L.
Published: December 2020

Green olives were found to contain an inhibitor(s) of several species of lactic acid bacteria usually associated with the Spanish-type brined olive fermentation. The inhibitor was demonstrated by the presence of inhibition zones surrounding tissue which had been cut from frozen olives and implanted in a seeded nutritive agar medium. Relative potencies of aqueous extracts of frozen olives were determined by a paper disc assay method. The Mission variety of olive contained the most inhibitor, and the Manzanillo and Ascolano, about 50 and 40% as much as the Mission variety, respectively. Sevillano and Barouni varieties contained comparatively little inhibitor. Effects of the inhibitor on growth rates of lactic acid bacteria were determined by adding various amounts of a concentrated aqueous extract of olives to a nutritive broth medium contained in screw-capped tubes. Of the four species of lactic acid bacteria tested,
Leuconostoc mesenteroides
was the most sensitive, and
Lactobacillus plantarum
was the least sensitive;
Pediococcus cerevisiae
and
Lactobacillus brevis
were intermediate in sensitivity. Extracts possessed a bactericidal property, as evidenced by their effect on
L. mesenteroides
. Sodium chloride, especially at concentrations of about 5% and higher, greatly increased the effectiveness of the inhibitor. The inhibitor was ethyl alcohol-soluble and was stable when heated at 100 C in aqueous solution. Potencies of extracts were reduced greatly by adjustment to
p
H 10, but no appreciable effect was noted by adjustment to
p
H 0.8.

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Fig. 1
Studies on Survival of Bacteria: Rhythmic Response of Microorganisms to Freeze-Drying Additives
Authors: Heckly R. J. , Dimmick R. L. , Guard Nancy
Published: December 2020

Various materials were mixed with suspensions of
Serratia marcescens
and other organisms. Samples were removed and frozen at intervals after mixing; the number of cells that survived both freeze-drying and exposure to air varied rhythmically as a function of time between mixing and freezing. When assayed before or immediately after drying there were essentially no fluctuations. The response was evident only when these dried samples were exposed to air. In a typical experiment, the number of cells surviving in the sample frozen 30 sec after adding propyl gallate was at least 10 times that in samples frozen either 20 sec earlier or 20 sec later. Other “peaks” in survival were observed at approximately 125 and 450 sec, but the times at which the peaks were observed were not consistent from one experiment to the next. Although we have been unable to control or predict the time at which maxima in resistance occur, we have shown that the phenomenon does occur with
Escherichia coli
and
Saccharomyces cerevisiae
as well as with
S. marcescens
. Furthermore, a rhythmic response also was obtained after a change in
p
H or cell concentration. It appears that microorganisms respond physiologically and synchronously to changes in their environment, and some of these responses have survival value.
Effect of Microwaves on
Escherichia coli
and
Bacillus subtilis
Authors: Goldblith Samuel A. , Wang Daniel I. C.
Published: December 2020

Suspensions of
Escherichia coli
and
Bacillus subtilis
spores were exposed to conventional thermal and microwave energy at 2,450 MHz. The degrees of inactivation by the different energy sources were compared quantitatively. During the transient heating period by microwave energy, approximately a 6 log cycle reduction in viability was encountered for
E. coli
. This reduction was nearly identical to what is expected for the same time-temperature exposure to conventional heating. Heating of
B. subtilis
spores by conventional and microwave energy was also carried out at 100 C, in ice and for transient heating. The degree of inactivation by microwave energy was again identical to that by conventional heating. In conclusion, inactivation of
E. coli
and
B. subtilis
by exposure to microwaves is solely due to the thermal energy, and there is no per se effect of microwaves.
Microbial Conversion of Acetanilide to 2′-Hydroxyacetanilide and 4′-Hydroxyacetanilide
Authors: Theriault Robert J. , Longfield Thomas H.
Published: December 2020

Approximately 700 cultures of various types were examined for their ability to hydroxylate acetanilide. The major product formed by unidentified
Streptomyces
species RJTS-539 was identified as 4′-hydroxyacetanilide (
N
-acetyl-
p
-aminophenol). This culture gave a peak yield of 405 mg per liter from 1,000 mg of acetanilide per liter. Considerably lower yields of 4′-hydroxyacetanilide were isolated from
S. cinnamoneus
NRRLB-1285. The major conversion product of acetanilide formed by
Amanita muscaria
F-6 was identified as 2′-hydroxyacetanilide, with a peak yield of 433 mg per liter from 1,000 mg per liter of substrate. A small amount of 4′-hydroxyacetanilide was also formed. Six other
Streptomyces
cultures formed small amounts of one or two products identical or similar to 2′-hydroxyacetanilide or 4′-hydroxyacetanilide as determined by thin-layer chromatography and ultraviolet spectra.
Effects of Supplemental Calcium or Calcium-binding Agents on Staphylococcal Bacteriophage Proliferation in Skim Milk
Authors: Das N. K. , Marshall R. T.
Published: December 2020

Additions of 0.0005 N calcium borogluconate to Trypticase Soy Broth (TSB) produced an increase in phage titer about 1 million-fold, whereas its addition to skim milk resulted in about a 100-fold decrease in the maximal titer. Supplemental calcium had a stimulatory influence on bacterial growth in TSB but not in skim milk. Studies were made of the effect of binding of calcium of skim milk on the proliferation of staphylococcal bacteriophage. Sequestering the calcium with 2% phosphate mixture inactivated the phages without affecting the bacterial growth. However, chelation of calcium by 0.012% ethylenediaminetetraacetic acid produced an inhibitory effect on both the phages and the bacteria.
Production of Interferon in Mice: Effect of Altered Gaseous Environments
Authors: Huang Kun-Yen , Gordon Francis B.
Published: December 2020

Effects of altered gaseous environments (parabarosis) on interferon production in mice were studied, with Newcastle disease virus (NDV) as the inducer. Increased levels of interferon in lung tissue were observed when mice were exposed to 11% O
2
in N
2
for 3 days before and after, or only after, injection of NDV. However, serum interferon levels remained unchanged. Exposure of mice to 77% O
2
for up to 7 days did not affect the response to interferon induction as assayed in lungs or sera. Interferon levels were significantly depressed in mice exposed to a simulated depth of 213 ft in seawater [with normal partial pressure of O
2
(pO
2
) in N
2
] for 2 or 4 weeks. Whereas definite depression of interferon was also observed in mice maintained at a simulated altitude of 37,000 ft (with normal pO
2
) for 2 weeks, those maintained at the same condition for 4 weeks showed a normal level of interferon. The results obtained with hypoxia are compatible with other reports on the influence of O
2
tension on viral infection. The factors responsible for alterations observed in interferon level in mice kept in normal pO
2
, but under altered pressure, have not yet been identified.
Microassay for Human and Chick Cell Interferon
Authors: Tilles Jeremiah G. , Finland Maxwell
Published: December 2020

The microassay for human and chick interferon described in this paper required much smaller amounts of samples and reagents and considerably less time and effort than the plaque reduction assay while yielding comparable results.
Effect of Methionine and Sulfate on the Metabolism of
Cephalosporium acremonium
Authors: Caltrider P. G. , Huber F. M. , Day L. E.
Published: December 2020

The metabolism of
Cephalosporium acremonium
grown in a complex medium supplemented with DL-methionine or inorganic sulfate was studied. More growth occurred in a sulfate medium than in a methionine medium. Methionine-grown cells had an increased rate of respiration, a higher rate of catabolism with acetate and glucose as substrate, and higher specific activities of certain respiratory enzymes than sulfate-grown cells. Labeled acetate and glucose were assimilated at a faster rate by methionine-grown cells than sulfate-grown cells. Taurine, cystathionine, and small quantities of four acidic compounds were present in the amino acid pool of methionine-grown cells, but they were not detected in the pool of sulfate-grown cells. The differences in metabolic activity of sulfate and methionine-grown cells are discussed in regard to cephalosporin C synthesis.
Distribution of Thiamine, Biotin, and Niacin in the Sea
Authors: Natarajan K. V.
Published: December 2020

The distribution of thiamine, biotin, and niacin was investigated in surface waters collected from 20 stations in southeast Alaska, by use of bioassay methods. A marine yeast,
Cryptococcus albidus
, was used for thiamine, and mutants of the marine bacterium
Serratia marinorubra
were used for biotin and niacin. Thiamine was found in 6 (38%) of the samples in amounts ranging to 200 ng/liter; biotin was found in 8 (38%) of the samples in amounts ranging to 3.1 ng/liter. Niacin was found to be completely absent in all of the samples assayed. The significance of the presence of thiamine and biotin in the productivity of the area is discussed.
Ultraviolet Bactericidal Irradiation of Ice
Authors: Ladanyi P. A. , Morrison S. M.
Published: December 2020

We investigated the germicidal activity of 2,537 A ultraviolet (UV) radiation on bacteria in ice cubes of varying thickness and in aqueous suspensions beneath an ice layer. The test bacteria used were
Escherichia coli, Serratia marcescens, Bacillus subtilis
, and
Sarcina lutea
; aqueous suspensions of the selected organisms were frozen into ice cubes, 2 mm to 30 mm thick, at -20 C. The cubes were irradiated for 1 min, whereas the suspensions of bacteria were placed beneath an ice block (19 cm thick) and were irradiated for 0.5 to 15 min. In both groups of experiments, the standard plate count method was used to compare the number of bacteria surviving the UV treatment with the number of bacteria in the untreated controls. The results showed that 1 min of UV treatment killed as many as 97% of the gram-negative and at least 60% of the gram-positive test bacteria (freezing survivors) frozen in ice cubes 30-mm thick. Within 15 min, UV light transmitted through a 19-cm thick ice block inactivated 98% of the bacteria suspended in the buffer solution. We concluded that the UV rays were able to penetrate at least 19 cm of ice and still retain enough energy to kill bacteria. However, the UV penetration depended greatly on the optical quality of the ice. Although it was not the purpose of these experiments to find a practical method for sanitizing ice, the results of this study and of our other unpublished experiments indicate that UV light has adequate penetrating power to be considered practical in certain selected applications.
Isolation and Characterization of Antibiotic LL-AC541
Authors: Zbinovsky V. , Hausmann W. K. , Wetzel E. R. , Borders D. B. , Patterson E. L.
Published: December 2020

A new basic, water-soluble antibiotic designated LL-AC541, produced by a strain of
Streptomyces hygroscopicus
(NRRL 3111), was isolated as a hydrochloride salt; [α]
D
25
, — 58°, melting point, 200 to 215 C (decomposition). It is structurally related to streptothricin but does not contain β-lysine. Isolation procedures, physicochemical properties, antimicrobial spectrum, and in vivo testing results are presented. Another very closely related antibiotic obtained from the same fermentation is briefly described.
Liquid Nitrogen Preservation of Standard Inoculum: Gas-Phase Storage
Authors: Mcdaniel L. E. , Bailey E. G.
Published: December 2020

Liquid nitrogen storage was the most satisfactory of several methods tested for supplying standard
Streptomyces viridoflavus
inoculum for laboratory and pilot plant experimentation. Shake-flask cultures were subdivided into sterile cotton-plugged ampoules and stored in the gas space of a liquid nitrogen refrigerator. There were no detectable changes in viability or in candidin-producing capacity over a 12-month test period. The procedure also proved satisfactory with all other organisms tested.
Effect of Statolon-induced Interferon on Antibody Formation
Authors: Pindak Frank F.
Published: December 2020

The effect of statolon-induced interferon on immune response was investigated. Young adult Swiss albino mice were immunized with chicken red blood cells or infectious mengovirus. The red blood cells were injected three times and the virus twice at 2-week intervals, with or without treatment with statolon 24 hr before the inoculations. The effect of interferon on antibody formation was measured by determinations of hemagglutinating, hemolytic, and virus-neutralizing antibodies in the sera of treated and nontreated groups. The hemagglutinin and hemolysin titers after each successive inoculation were equal in both groups, indicating that interferon had no effect on their production. A decrease in the primary response to the viral antigen was associated with interferon induction; the booster response was unaffected. The possible use of interferon inducers as attenuants for immunization with live virulent viruses is discussed.
Differential Tolerance of Streptomycetes to Sodium Chloride as a Taxonomic Aid
Authors: Tresner H. D. , Hayes Jean A. , Backus E. J.
Published: December 2020

A survey was made of the NaCl tolerance of approximately 1,300
Streptomyces
strains belonging to 313 species. The growth medium of the organisms was supplemented with a graded series of NaCl concentrations (4, 7, 10, and 13%). Only 1.8% of the species could not tolerate 4% NaCl; 26.9% could grow at a maximum of 4%; 49.7% could tolerate a maximum of 7%; 18.8% could grow at a maximum of 10%; and only 2.8% could tolerate 13% NaCl. In evaluating the relationships of NaCl tolerance to various taxonomic features, higher tolerance was statistically associated with the “yellow” and possibly the “white”-spored streptomycetes, whereas the “red”-spored series tended to have lesser tolerance. Higher tolerance was also indicated for spiny-spored species, as a group, than for smooth-spored forms. Likewise, nonproducers of melanin, collectively, were more NaCl tolerant than melanin-producing species. Uniformity of test responses between strains of species studied suggested the usefulness of NaCl tolerance as a taxonomic criterion.
Isolation and Characterization of a Cellulose-utilizing Bacterium
Authors: Han Y. W. , Srinivasan V. R.
Published: December 2020

A cellulose-decomposing aerobic and mesophilic bacterium has been isolated from soils of sugar cane fields. The terminal dilution method was adapted to isolate a single clone of cellulolytic organism from closely related contaminants. The cultural and physiological characteristics of the isolate were studied, and the organism was identified as a member of the genus
Cellulomonas
. The isolate excreted cellulase into the menstruum, and it hydrolyzed various cellulosic materials producing cellobiose as the final breakdown product in the menstruum. When sugar cane bagasse was properly treated with alkali and heat, the organism could decompose up to 90% of the initial substrate within 5 days. Amino acid analysis of the cell crop revealed a high content of lysine, and the essential amino acid pattern compared favorably with that of Food and Agricultural Organization reference protein.