bluuebunny/crossref_metadata_2025 huggingface dataset:
Harvesting of Algae by Froth Flotation
Authors: Levin Gilbert V. , Clendenning John R. , Gibor Ahron , Bogar Frederick D.
Published: December 2020

A highly efficient froth flotation procedure has been developed for harvesting algae from dilute suspensions. The method does not depend upon the addition of flotants. Harvesting is carried out in a long column containing the feed solution which is aerated from below. A stable column of foam is produced and harvested from a side arm near the top of the column.

The cell concentration of the harvest is a function of pH, aeration rate, aerator porosity, feed concentration, and height of foam in the harvesting column. The economic aspects of this process seem favorable for mass harvesting of algae for food or other purposes.
Effects of Arene-type Hydrocarbon Air Pollutants on
Bacillus megaterium
Authors: Won William D. , Thomas Jerome F.
Published: December 2020

Effects of certain common carcinogenic and noncarcinogenic polycyclic aromatic hydrocarbon organic air pollutants on
Bacillus megaterium
cultures were noted. Depending on the medium used, either growth suppression or induction of atypical cell forms was observed in cultures grown in the presence of a carcinogen. By contrast, no such alterations were apparent in cultures grown in media supplemented with a noncarcinogen. Both carcinogenic and noncarcinogenic hydrocarbons exerted an enhancing influence, of varying degree, on lipogenesis, glycolysis, and methylene blue reductase activity. A higher than normal level of these reactions, however, was associated with cultures exposed to a carcinogen. In addition, infrared examination of lipids revealed unique spectral characteristics for materials extracted from carcinogen-treated cultures. No difference was noted between materials derived from noncarcinogen-treated cultures and from control cultures.
Further Studies on Staphylococci in Meats,
Authors: Jay James M.
Published: December 2020

Of 272 isolates of
Staphylococcus aureus
recovered from 173 samples of 10 market meats from 27 stores, 173 (63.2%) were phage typable, employing 28 phages. Sixty per cent of the phage-typable strains belonged to group III, followed by 14.5% to mixed groups I and III, 10.4% to Group I, 8.7% to all mixed groups, 4.6% to group II, and 1.7% to group IV. The most commonly recovered patterns were 83, 53/83, and other similar combinations of 53. The nonpigmented strains which did not have bound coagulase were less phage sensitive than the pigmented strains having bound coagulase. None of the isolates were resistant to novobiocin, kanamycin, chloramphenicol, and erythromycin. Twenty-three per cent were resistant to streptomycin, 17% to ristocetin, 11% to penicillin, and 4.4% to chlortetracycline. The phage types are compared to those of other food and human isolates and found not to differ too greatly. Their possible origins into the meats are discussed.
The Microflora of Frozen Passionfruit Nectar Base
Authors: Aea Raymond T. F. , Bushnell O. A.
Published: December 2020

A considerable and varied microflora is introduced into passionfruit nectar base under present methods of production. In spite of the great acidity of the nectar base (pH range: 2.8 to 3.2), the high sucrose concentration (approximately 50%), and storage at -20 C, remnants of the microflora persist for a year or longer. During storage, however, there is a steady and gradual decrease, until after about 18 months the microflora is near to extinction. Sample regression lines show straight-line slopes for this diminution in numbers.

A battery of nine media was used to grow a representative aerobic flora. Purified cultures of isolates were identified to genera. Yeasts were the most numerous organisms in all samples, followed by molds, bacteria, and streptomycetes. The bacteria were the first group to disappear during storage. No fecal streptococci or gram-negative bacilli were found in any samples.
Culture and Metabolism of the Rumen Ciliate
Epidinium ecaudatum
Crawley
Authors: Gutierrez J. , Davis R. E.
Published: December 2020

The rumen ciliate
Epidinium ecaudatum
was cultured for 6 months in the presence of two strains of bacteria, starch, alfalfa, linseed oil meal, and buffered saline. The cultures required daily transfer and addition of fresh substrate. The protozoan degraded starch, soybean oil meal, linseed oil meal, and cottonseed oil meal, and the fermentation end products from the breakdown of starch were acetic and butyric acids with traces of formic, propionic, and lactic acids, carbon dioxide, and hydrogen. The relationship of
E. ecaudatum
to other species of rumen oligotrichs and bacteria is discussed.
Use of the Replica-Plate Technique in Studies of Toxicity of Metals and Plastics to Bacteria
Authors: Rosenwald A. J. , Hodge H. M. , Metcalfe S. N. , Hutton R. S.
Published: December 2020

A study was made on the efficacy of commonly used test methods to provide useful data concerning toxicity of construction materials to bacteria. Tests such as growth and storage of liquid cultures, which are based on plate counts, appeared to be less efficient in providing interpretable data than were tests which used solid media. The conjunctive use of zone inhibition and an adaptation of the replica-plate technique used in bacterial genetics supplied as much information as other tests, but these solid-media tests were easier to perform, accommodated more test samples per unit of bacterial culture, and the data were more easily understood.
Statistical Measurement of Biotin, Thiamine, and Zinc Concentrations Required for Maximal Growth of
Arthrobotrys conoides
Authors: Grant C. L. , Coscarelli Waldimero , Pramer David
Published: December 2020

An experiment of central composite design was performed to determine simultaneously the most suitable concentration of each of three nutrients essential for proliferation of the nematode-trapping fungus,
Arthrobotrys conoides
, and to detect any significant interaction that occurred when they were supplied at different levels. Regression analyses of the results obtained revealed that for maximal growth of
A. conoides
in a glucose-inorganic salts medium, biotin, thiamine, and zinc were required at concentrations of 5, 100, and 400 μg/liter, respectively. No interaction of significance was detected. The analytical procedures are presented in detail, and the benefits that accrue from a statistical approach are discussed.
Eflect of Relative Humidity on the Bactericidal Activity of Propylene Oxide Vapor
Authors: Himmelfarb Philip , El-Bisi Hamed M. , Read R. B. , Litsky Warren
Published: December 2020

Because of the low toxicity of its breakdown product, propylene oxide (PO) vapor will play an increasingly important role in the preservation of foods. It is therefore necessary that the diversified variables which influence effectiveness of PO treatment be thoroughly investigated and understood prior to advocating its general use in industry. Accordingly, the present study was undertaken to determine the effect of relative humidity (RH) upon the bactericidal activity of PO sterilant atmospheres. Death rates were established at increasing RH values of < 1, 52, 65, 80, and 98% and under constant conditions of concentration, pressure, and temperature. Test bacterial populations were preconditioned to corresponding moisture levels. Results indicate that gram-positive cocci were relatively insensitive to PO vapor at dry conditions but became progressively less resistant with the increase in RH up to a maximum of 65 to 70%. Lactic acid bacteria and gram-negative rods were much more sensitive at dry conditions, showing much less dependency upon water vapor.
Bacillus subtilis
spores elicited the highest degree of resistance but the death rate substantially increased with the increase in RH.
Evaluation of Factors Affecting the Survival of
Escherichia coli
in Sea Water
Authors: Scarpino P. V. , Pramer David
Published: December 2020

The relationship between death of cells of
Escherichia coli
in artificial sea water and time was established as linear, and statistical tests demonstrated that the most suitable measure of survival was log per cent after 24 hr. Survival of
E. coli
in water supplemented with cysteine at levels of 0.284 × 10
-6
to 284 × 10
-6
m
was increased greatly over that in untreated water. To provide an insight into the mode of action of cysteine, the effect of concentration of various sulfhydryl and disulfide compounds was measured, and the influence of several compounds that lack a functional sulfur group but which are capable of affecting oxidation-reduction potential was determined. Moreover, a number of substances related structurally to cysteine were tested to ascertain their influence on the survival of cells of
E. coli
in artificial sea water. It appeared that the beneficial effect of cysteine was not due to the sulfhydryl group of the amino acid or to the ability of the compound to influence oxidation-reduction potential. Some sulfhydryl compounds had no favorable effect and, in general, disulfides were more active than the corresponding sulfhydryl compounds. Substances that lack a functional sulfur group but influence oxidation-reduction potential had no significant activity. The beneficial effect of a number of compounds related structurally to cysteine indicates that both an amino and carboxyl group are required for activity. It is suggested that cysteine and other amino acids act to increase survival of cells of
E. coli
in sea water by a chelation mechanism.
Fungi Growing on Jute Fabrics Deteriorating under Weather Exposure and in Storage
Authors: Chakravarty T. , Bose R. G. , Basu S. N.
Published: December 2020

Special media suitable for the isolation of fungi growing on jute were developed. Species that would better resist sunlight, such as organisms with dark hyphae and spores or closed fruit bodies, predominated on weather-exposed fabrics. Several strongly cellulolytic organisms not previously implicated in fiber decomposition were isolated from this source. On the other hand, the fungi obtained from jute materials damaged in storage were mostly of the familiar types. Most of the newly isolated fungi are generally missed on ordinary media, but they probably play an important role in the natural decomposition of jute materials.
Effects of a Quaternary Ammonium Compound on
Escherichia coli
Authors: Ceglowski W. S. , Lear S. A.
Published: December 2020

Increasing amounts of tetradecyldimethylbenzyl ammonium chloride (TAC) were lethal to an increasing proportion of an actively growing culture of
Escherichia coli
. The loss of nucleic acid material by actively growing
E. coli
did not appear to play a major role in the lethal effect. It was found that lag-phase cells were more sensitive than logarithmic-phase cells to the lethal effect of TAC. The effect of TAC on the lysozyme sensitivity of the test organism was compared with that obtained using disodium dihydrogen ethylenediaminetetraacetate (EDTA). Although TAC was found to render the test organism susceptible to lysozyme, the degree of lysis never reached that attained with EDTA.
Comparison of Several Methods for Preserving Bacteriophages
Authors: Clark William A.
Published: December 2020

A wide variety of bacteriophages were processed and stored under different conditions to compare methods for long-term preservation. Specimens were stored for 2 years at room temperature (24 to 28 C) and at 4 C as broth lysates in 50% glycerol, dried, and freeze-dried. Titers determined after processing indicated that, of the broth, glycerol, and freeze-dry methods, freeze-drying was most damaging to the phages tested, glycerol less damaging, and the broth method least damaging. After 2 years, titers of broth lysates were generally higher than those of glycerol or freeze-dried preparations. Dried preparations generally did not prove satisfactory. Preparations stored at 4 C showed better titers than those kept at room temperature. All titers declined with time regardless of the conditions of preservation.
Experiences with the Coulter Counter in Bacteriology
Authors: Swanton Ellen M. , Curby William A. , Lind Howard E.
Published: December 2020

Viable and killed suspensions of
Staphylococcus aureus
SM,
Escherichia coli
, and
Serratia marcescens
, as well as polystyrene spheres, 0.81 and 2.85 μ in diameter, were counted electronically with a model A Coulter Counter. Simultaneous counts by standard bacteriological methods and microscopy were done for purposes of control and comparison with the data from the Coulter Counter. Results indicated: (i) electrical characteristics of different bacterial populations are different; (ii) electronic counts were consistent for species used; (iii) live
S. aureus
exhibits a denser pattern of thick bright pulses on the cathode-ray tube than does live
E. coli
; (iv) killed bacteria resemble inert particles in pulse pattern; and (v) some viable bacteria do not react independently of current flow, as do inert particles and killed bacteria.
Fungus Spores as Uniform Reference Particles for Use in Absolute Cell Counts
Authors: Klapper Betty F.
Published: December 2020

Spores of several different fungi were tested as microspheres in a recently described method of making absolute cell counts of bone-marrow cells. For a particular fungus to qualify for use in the counting method, it must be readily obtained and must produce large quantities of spores that are highly uniform in size. Thus far, the most satisfactory microspheres we prepared were the basidiospores of
Calvatia gigantea
, the giant puffball. This common field organism is a prolific spore producer. A simple procedure for obtaining spore suspensions was devised. Another source of microspheres is the conidia of species of
Aspergillus
and
Penicillium
. These widespread organisms were easily grown in the laboratory and also provided heavy spore harvests. It was suggested that conidia of these or additional species of fungi may be found useful in other kinds of research requiring small, highly uniform particles.
Precise Adsorption Method for Measuring the Percentage of Dead Bacterial Cells
Authors: Vairo Marina L. R. , Borzani Walter
Published: December 2020

It was observed that Freundlich's law is obeyed when methylene blue is adsorbed from different aqueous solutions by mixtures of dead and live bacterial cells. A simple and precise colorimetric method was developed for determining the percentage of dead cells.
Induced Autolysis of
Aspergillus oryzae
(
A. niger
group)
Authors: Emiliani Ezio , de Davie I. Ucha
Published: December 2020

The examination of substances formed during induced autolysis by
Aspergillus niger
was continued in this work, which dealt in particular with carbohydrates. The autolysate contained a large amount of
d
-glucose (14 to 20% dry wt) and traces of glycolic aldehyde, dihydroxyacetone, ribose, xylose, and fructose. It also contained glycopeptides (about 10% dry wt), which were split from the cell wall during autolysis and which differed from one another in their level of polymerization and their composition. They were constituted by glucose and mannose, glucose and galactose, or mannose, glucose, and galactose (mannose being the most abundant in this case), and amino acids (chiefly alanine, serine, glutamic acid, and aspartic acid). During autolysis, only a part of the cell wall was dissolved, since it retained its shape. Upon further chemical hydrolysis, it produced mostly glucose and glucosamine, and smaller amounts of mannose, galactose, and amino acids. Presumably, glucomannoproteins and glucogalactoproteins were present in the intact cell as a macromolecular complex, constituting, together with chitin, the major part of the cell wall of
Aspergillus
.
Growth of Pure Cultures of Marine Phytoplankton in the Presence of Toxicants
Authors: Ukeles Ravenna
Published: December 2020

The effects of 17 toxicants on the growth of five species of algae in pure culture were studied. The two species displaying the greatest sensitivity to the action of each of the compounds tested were
Monochrysis lutheri
and
Phaeodactylum tricornutum
, and the most resistant species was
Protococcus
. Of eight different classes of toxicants tested, substituted urea compounds and a mercuric compound were most effective in inhibiting growth of all algal species at the lowest concentrations.
Bacterial Utilization of Ether Glycols
Authors: Fincher Edward L. , Payne W. J.
Published: December 2020

A soil bacterium capable of using oligo- and polyethylene glycols and ether alcohols as sole sources of carbon for aerobic growth was isolated. The effects of substituent groups added to the ether bonds on the acceptability of the compounds as substrates were studied. Mechanisms for the incorporation of two-carbon compounds were demonstrated by the observation that acetate, glyoxylate, ethylene glycol, and a number of the tricarboxylic acid cycle intermediates served as growth substrates in minimal media. The rate of oxidation of the short-chained ethylene glycols by adapted resting cells varied directly with increasing numbers of two-carbon units in the chains from one to four. The amount of oxygen consumed per carbon atom of oligo- and polyethylene glycols was 100% of theoretical, but only 67% of theoretical for ethylene glycol. Resting cells oxidized oligo- and polyethylene glycols with 2 to 600 two-carbon units in the chains. Longer chained polyethylene glycols (up to 6,000) were oxidized at a very slow rate by these cells. Dehydrogenation of triethylene glycol by adapted cells was observed, coupling the reaction with methylene blue reduction.
Antimicrobial Activity of Metal Chelates of Salts of 8-Quinolinols with Aromatic Hydroxycarboxylic Acids
Authors: Gershon Herman , Parmegiani Raulo , Nickerson Walter J.
Published: December 2020

Thirty-seven metal chelate complexes of salts of 8-quinolinols with aromatic hydroxycarboxylic acids were screened by the disc-plate method against strains of five bacteria and five fungi. The copper (II) chelates of 8-quinolinolium salicylate and 8-quinolinolium-3′-hydroxy-2′-naphthoate showed outstanding antifungal and good antibacterial properties and appear to be potentially more economical than copper (II) 8-quinolinolate.
Continuous Culture of Ruminal Microorganisms in Chemically Defined Medium
Authors: Quinn Loyd Y.
Published: December 2020

An apparatus is described which has been used for successful continuous culture of the ciliates from the rumen of cattle. Automatic control of feeding rate, pH, oxidation-reduction potential, temperature, stirring rate, aeration rate, salinity, and volume of the culture is provided for, using standard commercial equipment, whenever possible. The operation of this apparatus is described.
Continuous Culture of Ruminal Microorganisms in Chemically Defined Medium
Authors: Quinn Loyd Y. , Burroughs Wise , Christiansen William C.
Published: December 2020

Ruminal ciliates have been grown in continuous culture in chemically defined media and in the absence of viable bacteria. Oligotrichic ruminal ciliates seem to require insoluble carbohydrates for growth; the holotrichic ciliates require soluble carbohydrates, but at low concentrations. Both groups of ciliates utilize amino acids as their principal nitrogen source when these are supplied in micromolar concentrations; at millimolar concentrations, amino acids are toxic, possibly from excessive ammonia formation arising from ciliate deaminase activity. Holotrichic ruminal ciliates are destroyed by overdeposition of amylopectin when glucose is present above 0.1% concentration in the medium. Ecological requirements of ruminal ciliates are also described.
Characteristics of an Intracellular Proteinase System of a
Trichosporon
Species Isolated from Trappist-Type Cheese
Authors: Vorbeck Marie L. , Cone J. Frank
Published: December 2020

A greater yield of the active principle was obtained when the cells were allowed to autolyze than when mechanical methods of cell disruption were used. A marked increase in activity was obtained when the crude cell extracts were held for 18 hr at 25 C after acidification to pH 5.0. The activated enzyme was partially purified by precipitation with 95% ethanol. This partially purified extract was most active at pH 5.8, and showed activity over a temperature range of 10 to 42 C. Its rate of activity was markedly decreased by sulfhydryl-binding agents. It exhibited its greatest degree of thermostability at pH 5.0.
Prevention of Loss of Streptomycin Production on Repeated Transfer of
Streptomyces griseus
Authors: Musílek Vladimír
Published: December 2020

The streptomycin-producing capacity of submerged cultures of
Streptomyces griseus
107 was nearly lost during repeated transfers on synthetic nutrient medium. This effect did not occur on the same nutrient medium from which Fe
++
was omitted. The physiological reason for this effect was discussed from the point of the relationship of iron-containing porphyrin enzymes to the process of streptomycin biosynthesis.
Continuous-Flow Mechanical Cell Disintegrator
Authors: Ross John W.
Published: December 2020

A mechanical cell disintegrator is described which efficiently ruptures bacteria, molds, actinomycetes, and yeasts. Cells were broken continuously in a chamber by rapid shaking of a mixture of cell suspension, plastic beads, and air. Volume capacity for complete breakage varied with experimental conditions and the microorganism involved, and ranged from 840 ml/hr to greater than 4,470 ml/hr. Subcellular preparations made with the machine retained a high level of enzymatic activity.
Some Physiological Characteristics of Two Sets of Phage-Propagating Strains of
Staphylococcus aureus
Authors: Solomon J. J. , Clemente C. L. San
Published: December 2020

A number of physiological characteristics were studied on some 29 strains of phage-propagating staphylococci belonging to the Basic International Series and the Seto-Wilson bovine-adapted set. All the cultures except strain 73 were coagulase-positive, with reciprocal titers ranging from 2 to 8,192. Strain 73 was again an exception with respect to phosphatase activity. Group 1 yielded high values for both phosphatase and oxygen uptake but low values for extracellular protein. Resistance to penicillin was demonstrated only by strains 80, 81, 53, 54, 75, and 77. Strain 70, one of the highest coagulase producers, alone showed no catalase activity. Mannitol was fermented by all coagulase-positive strains. Hemolysis of one or more of three kinds of erythrocytes (sheep, rabbit, and human) was a common characteristic of most strains. However, pigmentation was a nondiscriminating parameter. Although one-half of the cultures liquefied gelatin, most of them gave similar antibiotic-sensitivity tests, except the six which were penicillinase producers. There was little difference in growth rate for all strains. Comparison of coagulase production to cell size indicated that the high-titer strains were generally larger than the low producers. The foregoing evidence avers that, in addition to lytic spectrum, physiological properties can usefully characterize staphylococcal phage-propagating strains.
Effects of Ingredients Used in Condensed and Frozen Dairy Products on Thermal Resistance of Potentially Pathogenic Staphylococci
Authors: Kadan Ranjit S. , Martin W. H. , Mickelsen Ross
Published: December 2020

A cell suspension of
Staphylococcus aureus
(196E) was injected into raw skim milk which contained different concentrations of sugar, serum solids, fat, stabilizers, and emulsifiers. The ingredient samples were exposed for the desired length of time in a constant-temperature water bath (60 C). Standard plate counts were made, and the number of surviving organisms was determined. Regression coefficients for each ingredient concentration were calculated and plotted against the per cent ingredient concentration to give an indication of protective action. Analyses of variance were conducted on bacterial counts to test the protective action of each ingredient. A comparison of the number of survivors in different sugar concentrations showed that with up to 14% sugar all the organisms were killed within 30 min. In sugar concentrations above 14%, the number of survivors increased regularly with each increase in sugar concentration up to 57%, which was the maximum used. In concentrations of serum solids above 9%, some organisms survived 35 min of heat treatment. Butter fat, stabilizer, and emulsifier did not offer any protective action in the concentrations observed.
Nonbiological Conversion of Cephalosporin C to a New Antibiotic by Sodium Thiosulfate
Authors: Demain A. L. , Newkirk Joanne F. , Davis G. E. , Harman R. E.
Published: December 2020

The apparent stimulation of cephalosporin C biosynthesis by sodium thiosulfate is due to a nonbiological conversion of cephalosporin C to a new derivative, cephalosporin C
x
. The new compound is more active than cephalosporin C against the assay organism,
Escherichia coli
W-208. Cephalosporin C
x
retains the properties of ultraviolet absorption and resistance to penicillinase, but migrates more slowly than cephalosporin C in the paper-chromatographic system used.
Succinic Acid Turnover and Propionate Production in the Bovine Rumen
Authors: Blackburn T. H. , Hungate R. E.
Published: December 2020

High velocity constants for conversion of added succinate to propionate, together with estimations of pool size, showed that extracellular succinate is the major precursor of the propionate formed in the rumen. Some bacteria give off succinate as a final fermentation product which is decarboxylated by others to propionate.
Occurrence of Enterococci on Plants in a Wild Environment
Authors: Mundt J. Orvin
Published: December 2020

Enterococci were obtained from 14% of nearly 2,200 flowers, 3.4% of non-floral structures of angiosperms, and from 8.3% of samples of soil, water, and lesser plants of the Great Smoky Mountains National Park, an area little influenced by the presence of man. The enterococci were recovered from one or more flowers or flower clusters of 1,515 samples in 47 taxa, but not from flowers of 67 taxa with 654 samples. The per cent of recovery was influenced adversely by dense forest cover and by increase in elevation, as compared with recovery from flowers in sunny locations in the lower elevations. The per cent recovery increased directly with rising seasonal temperature, with the maximal per cent of recovery occurring in September. In no instance did all samples of a species of flower or plant yield enterococci on culture, and with only three genera,
Cacalia, Delphinium
, and
Mitchella
, were the bacteria obtained from more than 50% of the samples. Approximately 11% of the cultures isolated were identified as
Streptococcus faecalis
, 64% as the soft curd producing, caseolytic variant of
S. faecalis
, 4% as
S. faecalis
var.
zymogenes
, and 20% as
S. faecium
. The per cent distribution of these species on plants was reasonably similar to the distribution within wild animals in the same environment. It was concluded that the enterococci occurring on plants arise commonly from the wild animals, and that they do not represent plant-specific species or variants of the enterococci.
Fatty Acid Oxidation by Spores of
Penicillium roqueforti
Authors: Gehrig R. F. , Knight S. G.
Published: December 2020

When 1 μ
m
sodium octanoate was the substrate for spores, most of the molecule was recovered as CO
2
and no ketone was produced. However, when larger concentrations (20 μ
m
) were used as substrate, part of the molecule was converted to methyl ketone and part was completely oxidized. Optimal conditions for the production of 2-heptanone were determined because of the importance of this compound in giving aroma and flavor to mold-ripened cheeses. Optimal ketone formation was not dependent upon the temperature and length of time at which the spores were stored. The spore suspensions were stored for over 36 months at 4 C without losing their ability to convert octanoic acid to 2-heptanone. The oxidation of octanoic acid was inhibited by cyanide, carbon monoxide, mercury, 2,3-dimercapto-1-propanol, and α, α-dipyridyl. No ketone was produced under anaerobic conditions. Although no intermediates of fatty acid oxidation were isolated, since an active cell-free preparation could not be obtained, this investigation has yielded some evidence for the beta oxidation of the fatty acids by spores of
Penicillium roqueforti
.
Differentiation of
Streptococcus lactis
var.
maltigenes
from Other Lactic Streptococci
Authors: Gordon D. F. , Morgan M. E. , Tucker J. S.
Published: December 2020

Strains of lactic streptococci isolated from samples of raw milk which had developed a malty aroma were subjected to the cultural, physiological, and serological tests commonly employed in the classification of streptococci. None of the strains could be differentiated from
Streptococcus lactis
by these tests. Resting cells of strains which produced an organoleptically detectable malty aroma when cultured in milk were usually found to possess an active α-ketoacid decarboxylase, indicating the presence of the mechanism responsible for the characteristic aroma production. This decarboxylase activity was either weak or nonexistent in the nonmalty strains, and no activity was detected in known strains of
S. lactis, S. cremoris
, or
S. diacetilactis
. The malty strains usually produced higher acidities in milk than did the nonmalty strains, and, in most instances, they developed a granular type of growth sediment in broth, as opposed to a viscid sediment. Many of them gave weakly positive Voges-Proskauer tests in glucose broth with or without added citrate and appeared to be somewhat more resistant to nisin than the nonmalty strains.
Variations in Strains of
Streptomyces griseus
Isolated from a Degenerating Streptomycin-Producing Culture
Authors: Nomi Ryosaku
Published: December 2020

Streptomycin-resistant strains were isolated from a degenerated streptomycin-producing culture of
Streptomyces griseus
. From 250 resistant strains, 3 low, 2 intermediate, and 2 high potency strains were selected; these were compared in their morphological, cultural, physiological, and streptomycin-producing properties. Though no definite correlation between streptomycin production and the other properties could be obtained, the following correlations were considered as distinct differences among the low, intermediate, and high potency strains. (i) When streptomycin-producing ability degenerates, more submerged spore formation or fragmentation of mycelium into shorter filaments appears to occur. (ii) On agar medium, low and intermediate potency strains often show finely wrinkled growth; high potency strains do not show such characteristics. (iii) High potency strains excrete a distinct yellow soluble pigment on synthetic agar medium and on glucose-yeast extract agar, but low and intermediate potency strains show little or no ability to form this soluble pigment. (iv) In low and intermediate potency strains, inositol and arginine did not stimulate streptomycin production as they did in high potency strains. Streptamine showed some stimulating effect in the high potency strains and, in contrast, a depressive effect in intermediate potency strains, though streptidine showed a distinctly stimulating effect in all groups of strains employed.
Effect of Pasteurization on Survival of Certain Psychrophilic Bacteria
Authors: Macaulay D. M. , Hawirko R. Z. , James Norman
Published: December 2020

The effect of pasteurization on survival in milk of four strains of psychrophilic pseudomonads and of one strain of
Alcaligenes
was determined. Cell numbers were very low immediately after pasteurization, but increased after storage. The survival of psychrophilic bacteria in pasteurized milk appeared to depend on the initial number of organisms, and detection depended partly on the length of time of storage at 3 to 5 C.
Amino Acid Composition of the Protein from a Mushroom (
Pleurotus
sp.)
Authors: Bano Zakia , Srinivasan K. S. , Srivastava H. C.
Published: December 2020

Approximate analyses of mushroom protein (
Pleurotus
sp.) revealed that it contains 2.78% protein and 0.14% nonprotein nitrogen on a fresh-weight basis. A total of 17 amino acids, including all the essential amino acids, were qualitatively identified. Quantitative estimation of essential amino acids showed that, except for methionine and phenylalanine, all are in fairly high concentration. From these studies, it was concluded that the supplementation of this mushroom with cereal diet would help to overcome lysine deficiency.
Adequate Expression for Average Particle Size of Microbiological Aerosols
Authors: Kethley Thomas W. , Cown William B. , Fincher Edward L.
Published: December 2020

Attention was called to the fact that mathematical expressions exist for relating the various means commonly employed to describe the average particle size of microbiological aerosols. These include the count median diameter (
CMD
), the mass median diameter (
MMD
), the petri ratio (
P
a
) size, and the settling rate (
V
g
) size. It was pointed out that the diameters derived from the
P
a
and
V
g
are mathematically identical to the average surface-diameter (
SMD
), because this average is determined from the square of the diameters, a relationship which also describes the settling of particles by the Stokes equation. The useful equations are: log
SMD
= log
CMD
+ 2.3026 log
2
σ
g
and log
MMD
= log
CMD
+ 6.9078 log
2
σ
g
where σ
g
is the standard geometric deviation, and the
CMD
is determined on a count basis and the
MMD
on a weight basis. It was suggested that the
SMD
is the most adequate expression for the average particle size of microbiological aerosols.
Bacterial Content in Samples from Different Sites in the Rumen of Sheep and Cows as Determined in Two Culture Media
Authors: Munch-Petersen E. , Boundy C. A. P.
Published: December 2020

Samples of material from the rumen of cattle and of sheep were cultured in both Gall Broth (GB) and Reinforced Clostridium Medium (RCM). Samples were taken, at monthly intervals, from five sites in cattle and two sites in sheep in two series and, at weekly intervals, from two sites in cattle and in sheep in two series. Comparisons were made of the growth of organisms in the media, using the number of fertile tubes per set of six dilutions as a measure of the viable count. RCM gave a greater number of fertile tubes than GB with samples from cattle, but the reverse was the case with samples from sheep. Real differences in the number of fertile tubes from different sites in cattle were found at different times, but there was no consistent pattern. Simultaneous sampling from different sites in the rumen is, therefore, essential to provide an estimate of sampling error within animals. Although no site to site differences were detectable with rumen material from sheep, it is advisable to take more than one sample at a given time to assess sampling error.
Maintenance of the Rumen Microbial Population in Continuous Culture
Authors: Rufener W. H. , Nelson W. O. , Wolin M. J.
Published: December 2020

The design and use of an apparatus for continuous in vitro cultivation of the mixed bovine rumen microbial population are described. Data relative to the concentrations and proportions of volatile fatty acids produced, methanogenesis, carbon dioxide production, and survival of bacteria and protozoa indicated that an essentially normal in vivo fermentation pattern was maintained in vitro for experimental periods of from 3 to 10 days. The continuous cultures were responsive to major changes in type of feed intake. A change from grain to hay resulted in increased acetate and decreased propionate production, whereas decreased acetate and increased propionate resulted when feed intake was changed from hay to grain. Methanogenesis, volatile fatty acid production, and the numbers of microorganisms in the cultures were proportional to the amount of feed materials added up to levels calculated to approximate the in vivo maintenance requirement of the adult bovine.
Polysaccharide Produced by the Genus
Pullularia
Authors: Ueda Seinosuke , Fujita Kazuyoshi , Komatsu Kinji , Nakashima Zun-ichi
Published: December 2020

A dextranlike polysaccharide was found to be produced on substrates of sucrose, maltose, glucose, and fructose by growing cells of various strains of the genus
Pullularia
. The polysaccharide, obtainable in amounts as large as 2 to 3 g per 100 ml of culture medium using various carbohydrates as the carbon source, was soluble in cold water but not in 50% alcohol. The polysaccharide obtained had a α

d

= +197.5° (c = 0.2 in water), and its molecular weight, determined by the light-scattering method, was found to be approximately 250,000.
Changes in the Microflora of Haddock Fillets and Shucked Soft-Shelled Clams After Irradiation with Co
60
Gamma Rays and Storage at 0 C and 6 C
Authors: Masurovsky E. B. , Voss J. S. , Goldblith S. A.
Published: December 2020

Frequency distribution patterns of aerobic-facultative microflora, obtained by random selection of macrocolonies from samples of haddock fillets and shucked soft-shelled clams before and after treatment with doses of from 50,000 to 800,000 rad of Co
60
gamma rays, are presented, with analyses and interpretation. The data showed that a decided change occurred in the constitution of the microbial populations of both products: from a mixed gram-negative—gram-positive flora to a predominantly gram-positive flora immediately after irradiation. The great majority of these surviving microorganisms were micrococci, sporeforming bacilli, and certain yeasts, molds, and actinomyces. During storage at refrigeration temperatures above freezing, the microflora changed from the descendants of the more radioresistant gram-positive species to the more prolific gram-negative psychrophilic species that flourish at these low temperatures. Micrococci and gram-positive rods declined somewhat during the rise of the actively proteolytic-lipolytic pseudomonads and related species, but still remained at high enough levels to contribute significantly to the spoilage observed at different times in storage. The eventual spoilage of haddock fillets was characterized by discoloration of the cream-white tissue with water-soluble yellow, green, and red bacterial pigments; degradation of the tissue, by proteolytic and other microbial enzymes, to a watery, flaccid mass; and formation of volatile compounds that smelled putrid, rancid, and generally foul and pungent. Shucked soft-shelled clams displayed a different spoilage pattern, changing to a variegated brown-gray and forming a matted or loose gelatinous mass from which arose stale, acrid, putrid, sulfurous odors. These differences are believed to be attributable to the varied biochemical nature of the tissues involved, the Eh potential within the tissues, the time sequence of microfloral change, and the species and types of microorganisms associated with each product. Staphylococci were present in small numbers in some of the samples tested, but did not appear to be species of public health significance. Gram-negative enteric rods were also encountered, but were considered to be of doubtful public health importance. More detailed investigations, designed to study the effects of Co
60
gamma radiations on such microbes in sea foods, would be useful in assessing the problem further.
Transformations of Progesterone by Basidiomycetes
Authors: Schuytema Eunice C. , Hargie Martha P. , Siehr Donald J. , Merits Ilmar , Schenck Jay R. , Smith Muriel S. , Varner Estie L.
Published: December 2020

A total of 254 basidiomycete cultures have been examined for their action on progesterone. Of these, 54 showed transformation products by thin-film and gas-liquid chromatography. The major product formed by eight of these organisms acting on progesterone has been isolated and identified.
Lipid Metabolism of Rumen Ciliates and Bacteria
Authors: Williams P. P. , Gutierrez J. , Davis R. E.
Published: December 2020

The total lipid and free fatty acid contents of
Isotricha intestinalis, Entodinium simplex
, and the rumen bacterial flora of the respective protozoa were determined. Warburg manometric data showed that the sodium salts of tributyrin, oleic, and acetic acids stimulated gas production in
I. intestinalis
, whereas tributyrin was stimulatory with
E. simplex
and less active with oleic and acetic acids. Rumen bacteria provided fatty acids produced lower manometric gaseous increases when compared with the protozoa. Volatile fatty acids were produced by
I. intestinalis
and rumen bacteria with tributyrin, but not with tripalmitin. Sodium oleate gave little volatile fatty acid response with
I. intestinalis
or rumen bacteria. Washed suspensions of
I. intestinalis
and rumen bacteria concentrated C
14
-labeled oleic, palmitic, stearic, and linoleic acids within the cells during short incubation periods. Autoradiographs demonstrated the conversion of C
14
-labeled oleic, palmitic, stearic, linoleic, and acetic acids in the rumen protozoa and bacterial cells.
Assay of Interferon Activity
Authors: Balducci M. , Verani P. , Balducci D.
Published: December 2020

At present there is a lack of standard criteria for the identification and evaluation of activity of antiviral compounds. Interferon was used to explore comparatively several laboratory methods. Interferon was produced in chick embryos and in chorioallantoic membranes suspended in vitro. Evaluation of interferon activity was performed by several methods: (i) percentage of inhibition of plaque-forming units; (ii) hemagglutinin reduction of challenge virus; (iii) titer of cytopathic effect of challenge virus; and (iv) plaque-inhibition test. The suggested methods for measurement are those which express the titer of challenge virus in plaque-forming units or in hemagglutinating units.
Fractionation of β-Glucosidases and Related Extracellular Enzymes from
Aspergillus niger
Authors: Li L.-h. , King K. W.
Published: December 2020

Industrial concentrates from
Aspergillus niger
culture filtrates were fractionated by ion-exchange and adsorption chromatography. Several other types of hydrolases were completely removed. Eight partially purified components were obtained. Using specific activity as an estimate of purification, one aryl-β-glucosidase was purified 35-fold. Another component showed 147-fold purification using a viscosimetric assay with carboxymethylcellulose as substrate. The aryl-β-glucosidase was distinctly more thermolabile than the carboxymethylcellulase.
Large-Scale Production of Protective Antigen of
Bacillus anthracis
in Anaerobic Cultures
Authors: Puziss Milton , Manning Lee C. , Lynch Joe W. , Barclay Eugene , Abelow Ira , Wright George G.
Published: December 2020

A production-proving test was described for the preparation, by the anaerobic culture method, of large volumes of culture filtrate containing immunologically potent protective antigen of
Bacillus anthracis
. The process consisted of the anaerobic culture of a selected production strain in a chemically defined medium. The culture was then clarified and sterilized by filtration through sintered-glass filters. The sterile culture filtrate was adsorbed onto a preformed aluminum hydroxide gel, and the stabilized gel-antigen complex was concentrated. The final product had high immunizing potency, as shown by both in vivo and in vitro assays, and was well tolerated in man. Stability of the product to accelerated aging was good, and storage at 4 C for 1 year caused only a minor loss in protective activity. Large volumes of the highly antigenic gel-adsorbed protective antigen were readily produced by the method described.
System of Color Wheels for Streptomycete Taxonomy
Authors: Tresner H. D. , Backus E. J.
Published: December 2020

In the sundry systems of streptomycete taxonomy, color of the sporulating aerial mycelium is frequently employed as a systematic criterion. Color series, each containing species of similar spore colors, are generally erected; however, the range of colors encompassed within a series is often not clearly delineated by the usual word description. Therefore, a system is proposed in which the color content of each series is more accurately defined by means of color tabs. Seven spore-color series are recognized (i.e., red, gray, yellow, blue, green, violet, and white), each of which is represented by a color wheel that displays the range of colors included therein. By comparing spore colors with the color wheels, unclassified isolates can readily be assigned to appropriate color groups.
Factors Affecting the Algicidal and Algistatic Properties of Copper
Authors: Fitzgerald G. P. , Faust S. L.
Published: December 2020

Data from laboratory studies are presented to show that, whereas five different sources of copper appear to be equally effective as toxic agents for algae, the medium in which toxicity tests are carried out has a great influence on the toxicity of copper. A technique of subculture is described for determining whether a concentration of a chemical is algicidal, algistatic, or nontoxic in action against a specific alga, and demonstrations are given of tests with algae illustrating each class of action.
Adverse Effect of Ammonium Salts on the Antibacterial Activity of Paraformaldehyde Solutions
Authors: Myers G. E. , McCready R. G. L.
Published: December 2020

The antibacterial activity of aqueous solutions of paraformaldehyde in concentrations from 0.1 to 0.4% (w/v) is bacteriostatic rather than bactericidal in the presence or absence of ammonium chloride. The presence of ammonium chloride significantly lengthened the time of exposure to paraformaldehyde necessary for inhibition of growth of the test organism (
Staphylococcus aureus
FDA 209) when unbuffered solutions were used. Elevation of the pH of the reacting mixture of paraformaldehyde and ammonium chloride by partial buffering lengthened the time of exposure necessary for inhibition of growth of the test organism. Decrease of antibacterial activity was concomitant with the disappearance of paraformaldehyde from the reacting mixture. The reaction of paraformaldehyde with ammonium chloride was rapid at room temperature (25 C) and at pH levels near neutrality. The fate of the reacting paraformaldehyde, including the possibility of the formation of hexamethylenetetramine or methylenimine, is discussed with particular reference to loss of antibacterial activity.
Resistance of Salmonellae Isolated in 1962 to Chlortetracycline
Authors: McWhorter Alma C. , Murrell Mary C. , Edwards P. R.
Published: December 2020

Among 652 salmonellae examined,
Salmonella typhimurium
displayed a much higher incidence of resistance to chlortetracycline than did other serotypes. Among
S. typhimurium
cultures from man, the incidence of resistance (38%) increased markedly over that of cultures isolated 3 years previously (13.9%), whereas a similar increase was not noted among cultures from fowls. Resistance among cultures from animals other than fowls (72.5%) was due largely to the high incidence of resistance among cultures from bovine sources (93.7%).
Preservation by Freeze-Drying and the Stability of Virulence of
Salmonella typhimurium
Authors: Simon Ellen M. , Stahl K. L. , Wilson J. B.
Published: December 2020

Differences in the ability to withstand freeze-drying were demonstrated among strains of
Salmonella typhimurium
. On the average, the number of viable cells in freeze-dried cultures stored at 5 C for 12 to 18 months was approximately one half as large as that found 24 hr after freeze-drying. The viability in samples stored at higher temperatures declined rapidly and was correlated with the dryness of the sample. The virulence for mice of three strains of
S. typhimurium
did not change appreciably when samples were kept for 1 or 2 years as freeze-dried samples stored at 5 C, or as agar cultures stored at 5 C or at room temperature.