bluuebunny/crossref_metadata_2025 huggingface dataset:
Metabolism of Deoxycorticosterone by Human Fecal Flora
Authors: Bokkenheuser Victor D. , Suzuki Jon B. , Polovsky Stuart B. , Winter Jeanette , Kelly William G.
Published: December 2020

21-Dehydroxylation, a feature of metabolism of corticoids in humans, was observed in mixed cultures of fecal flora of normal individuals on a Western diet. The model substrate, 11-deoxycorticosterone (DOC), was metabolized to 3α-21-dihydroxy-5β-pregnan-20-one (THDOC), 3α-hydroxy-5β-pregnan-20-one (pregnanolone), and to two unidentified structures, metabolites X and Y. DOC was not metabolized in all media supporting growth of fecal flora. Conversion required an initial pH between 6.0 and 8.0. 21-Dehydroxylation occurred within 4 days of incubation in media inoculated with 10
-1
to 10
-7
fecal suspensions. In higher dilutions, containing obligatory anaerobes only, DOC was converted to metabolite X and sometimes also to metabolite Y. The yield of pregnanolone was related to the promptness with which the specimen was processed, to the presence of cysteine in the medium, and to the concentration of substrate (optimum, 16 to 64 μg of DOC per ml). The yield of THDOC was related to the delay in the processing of the specimen, the concentration of substrate (maximum at 256 μg/ml), and aeration of the culture. Pure cultures of aerobic organisms of fecal origin either failed to metabolize DOC or converted it to metabolite Y. Pure cultures of fecal anaerobes converted DOC to metabolite X and sometimes also to metabolite Y. Neither THDOC nor pregnanolone was produced by pure cultures.
Evidence for the Occurrence of Specific Iron (III)-Binding Compounds in Near-Shore Marine Ecosystems
Authors: Estep Marilyn , Armstrong James E. , Van Baalen C.
Published: December 2020

Aqueous extracts of samples from representative types of near-shore marine ecosystems were examined for growth-promoting activity for the siderochrome auxotroph,
Arthrobacter
JG-9. Blue-green algal mat and sea grass samples gave strongly positive responses. Relative to Desferal (Ciba Pharmaceutical Co., Summit, N.J.), concentrations up to 110 ng/g (wet weight) of sample were found. In contrast, extracts of anaerobic muds or macroalgae gave no detectable activity. The hydroxamate type of iron chelator may be important in providing a form of iron in sea water readily utilized by the microalgae and marine higher plants.
Removal of Enteroviruses from Sewage by Bench-Scale Rotary-Tube Trickling Filters
Authors: Clarke Norman A. , Chang Shih Lu
Published: December 2020

The efficacy of a rotary-tube type of trickling filter for removing coxsackievirus A9, poliovirus 1, and echovirus 12 suspended in raw settled sewage was investigated. At filtration rates equivalent to about 10 MGD (million gallons per day)/acre (ca. 3,785 m
3
/day per acre), the filters removed 95% of the poliovirus, 83% of echovirus 12, and 94% of coxsackievirus A9. Coliform, fecal streptococci, biochemical oxygen demand, and chemical oxygen demand removals were remarkably similar, averaging 94, 92, 93, and 95%, respectively. At filtration rates equivalent to about 23 MGD/acre, 59% of the poliovirus, 63% of the echovirus 23, and 81% of the coxsackievirus A9 were removed. Coliform, fecal streptococci, biochemical oxygen demand, and chemical oxygen demand removals at this filtration rate were 68, 75, 72, and 56%, respectively. Viruses were assumed to be adsorbed to the biological slime growing in the filters, but attempts to disassociate the viruses from the slime were unsuccessful, indicating that the slime-virus complex is very stable or that the viruses were somehow inactivated. The data indicate that coliform and fecal streptococci reductions in this type sewage treatment process can be used as an index of virus reduction. Disinfection, however, must be used to ensure a virus-free final effluent.
Methyl Violet: a Selective Agent for Differentiation of
Klebsiella pneumoniae
from
Enterobacter aerogenes
and Other Gram-Negative Organisms
Authors: Campbell Lucy M. , Roth Ivan L.
Published: December 2020

Three selective media for differentiation of
Klebsiella pneumoniae
from
Enterobacter aerogenes
on the basis of colonial morphology were evaluated. Using methyl violet 2B as a selective agent, strains of
K. pneumoniae
isolated from urine, fresh water, and fresh produce were tested against other members of
Enterobacteriaceae
in addition to strains of
Aeromonas hydrophila
and
Pseudomonas aeruginosa
. Comparison of colonial morphology showed
K. pneumoniae
produced larger, smoother colonies than other bacteria tested. These media were developed to aid in presumptive separation of
K. pneumoniae
from
E. aerogenes
in the monitoring of bacterial quality of water.
Total Rinse Method for Microbiological Sampling of the Internal Cavity of Eviscerated Broiler Carcasses
Authors: Blankenship L. C. , Cox N. A. , Craven S. E. , Richardson R. L.
Published: December 2020

A method is described for spray-rinse sampling the entire visceral cavity of broiler chicken carcasses for microbiological analyses. The method is designed to provide a more comprehensive sample than swabbing or excision of small areas.
Bright Greenish-Yellow Fluorescence and Aflatoxin in Agricultural Commodities
Authors: Bothast R. J. , Hesseltine C. W.
Published: December 2020

The corn milling industry has widely accepted the presence of bright greenish-yellow fluorescence under a black light as a presumptive indicator of aflatoxin (a poison produced by the mold
Aspergillus flavus
). This test was applied to wheat, oats, barley, rice, coconut, white corn, yellow corn, peanuts, sorghum, and soybeans, and evaluated in the laboratory. Our study supported the use of bright greenish-yellow fluorescence as a presumptive test for aflatoxin in wheat, oats, barley, corn, and sorghum.
Fungal Growth on C
1
Compounds: a Study of the Amino Acid Composition of a Methanol-Utilizing Strain of
Trichoderma lignorum
Authors: Willetts Andrew
Published: December 2020

The amino acid composition of the C
1
-utilizing fungus
Trichoderma lignorum
, growing at the expense of methanol as the sole source of carbon, was determined. With the exception of an insufficient content of methionine, the essential amino acid composition of this novel protein source appears adequate in terms of the Food and Agricultural Organization Reference Protein for both direct and indirect use in the human diet as a food or animal feed, respectively.
Cellulase Production by a Thermophilic
Clostridium
Species
Authors: Lee B. H. , Blackburn T. H.
Published: December 2020

Strain M7, a thermophilic, anaerobic, terminally sporing bacterium (0.6 by 4.0 μm) was isolated from manure. It degraded filter paper in 1 to 2 days at 60 C in a minimal cellulose medium but was stimulated by yeast extract. It fermented a wide variety of sugars but produced cellulase only in cellulose or carboxymethyl-cellulose media. Cellulase synthesis not only was probably repressed by 0.4% glucose and 0.3% cellobiose, but also cellulase activity appeared to be inhibited by these sugars at these concentrations. Both C
1
cellulase (degrades native cellulose) and C
x
cellulase (β-1,4-glucanase) activities in strain M7 cultures were assayed by measuring the liberation of reducing sugars with dinitrosalicylic acid. Both activities had optima at pH 6.5 and 67 C. One milliliter of a 48-h culture of strain M7 hydrolyzed 0.044-meq of glucose per min from cotton fibers. The cellulase(s) from strain M7 was extracellular, produced during exponential growth, but was not free in the growth medium until approximately 30% of the cellulose was hydrolyzed. Glucose and cellobiose were the major soluble products liberated from cellulose by the cellulase. ZnCl
2
precipitation appeared initially to be a good method for the concentration of cellulase activity, but subsequent purification was not successful. Isoelectric focusing indicated the presence of four C
x
cellulases (pI 4.5, 6.3, 6.8, and 8.7). The rapid production and high activity of cellulases from this organism strongly support the basic premise that increased hydrolysis of native cellulose is possible at elevated temperature.
Feed Refusal Factors in Pure Cultures of
Fusarium roseum ”graminearum”
Authors: Kotsonis Frank N. , Smalley Eugene B. , Ellison Robert A. , Gale Carol M.
Published: December 2020

Isolations from 1972 Wisconsin feed refusal corn yielded predominantly cultures of
Fusarium roseum ”graminearum.”
With one possible exception, none of the selected isolates of this fungus induced emesis in pigeons, whereas six of nine isolates produced feed refusal responses in all test animals. A single isolate of
F. roseum ”equiseti”
also induced a severe refusal response and possibly slight emesis. None of the other fungi isolated from this corn (
F. moniliforme, Acremoniella atra
) or controls caused either emesis or feed refusal. Zearalenone was detected in all isolates and was shown to be partially responsible for refusal activity. The remaining activity was ascribed to one or more nonvolatile, neutral, relatively polar molecules. T-2 toxin, although not detected in these isolates, was shown to have dramatic refusal activity in rats.
Effects of Temperature and Crude Oil Composition on Petroleum Biodegradation
Authors: Atlas R. M.
Published: December 2020

The biodegradability of seven different crude oils was found to be highly dependent on their composition and on incubation temperature. At 20 C lighter oils had greater abiotic losses and were more susceptible to biodegradation than heavier oils. These light crude oils, however, possessed toxic volatile components which evaporated only slowly and inhibited microbial degradation of these oils at 10 C. No volatile toxic fraction was associated with the heavier oils tested. Rates of oil mineralization for the heavier oils were significantly lower at 20 C than for the lighter ones. Similar relative degradation rates were found with a mixed microbial community, using CO
2
evolution as the measure, and with a
Pseudomonas
isolate from the Arctic, using O
2
consumption as the measure. The paraffinic, aromatic, and asphaltic fractions were subject to biodegradation. Some preference was shown for paraffin degradation, especially at low temperatures. Branched paraffins, such as pristane, were degraded at both 10 and 20 C. At best, a 20% residue still remained after 42 days of incubation. Oil residues generally had a lower relative percentage of paraffins and higher percentage of asphaltics than fresh or weathered oil.
Physical Properties and Kinetic Behavior of a Cephalosporin Acetylesterase Produced by
Bacillus subtilis
Authors: Abbott Bernard J. , Fukuda David
Published: December 2020

An esterase that deacetylates cephalosporins was recovered from the supernatant of a
Bacillus subtilis
culture. It was partially purified by ammonium sulfate fractionation and ultrafiltration. The enzyme had a temperature optimum between 40 and 50 C and a pH optimum of 7.0. The molecular weight was estimated by gel filtration to be 190,000. The enzyme was very stable and retained greater than 80% of its activity after storage in solution at 25 C for 1 month. The esterase exhibited Michaelis-Menton kinetics with the substrates 7-aminocephalosporanic acid (7-ACA) and 7-(thiophene-2-acetamido)cephalosporanic acid (cephalothin); the

K
m

values were 2.8 � 10
-3
and 8.3 � 10
-3
M, respectively. The products of 7-ACA deacetylation were weak competitive inhibitors, and a

K
i

value of 5.0 � 10
-2
M was determined for acetate and of 3.6 � 10
-2
M for deacetyl-7-ACA. Weak product inhibition did not prevent the deacetylation reaction from going to completion. A 5-mg/ml solution of partially purified esterase completely hydrolyzed (>99.5%) a 24-mg/ml solution of 7-ACA in 3 h. Because of the kinetic properties and excellent stability, this enzyme may be useful in an immobilized form to prepare large quantities of deacetylated cephalosporin derivatives.
Detection of
Clostridium botulinum
Toxin by Local Paralysis Elicited with Intramuscular Challenge
Authors: Sugiyama H. , Brenner Shelley L. , Dasgupta B. R.
Published: December 2020

Clostridium botulinum
toxin can be identified by a characteristic, acute local paralysis that follows its injection into the gastrocnemius (“calf” muscle) of mice The local botulism can be elicited with slightly less than one-tenth the toxin amount that is needed to kill mice by the intraperitoneal (i.p.) challenge route. The practical sensitivities of the intramuscular (i.m.) versus i.p. tests are about equal, however, because maximum sample volume injectable i.m. is 0.1 ml as compared to the 0.5-ml range that can be given i.p. i.m. injection of 10 or more mouse i.p. mean lethal doses causes paralysis in about 1 h, and an i.m. injection of about 0.5 i.p. mean lethal doses causes paralysis in 3 to 4 h. Toxin neutralization by homologous type of antitoxin only can be demonstrated with an incubated mixture of toxin and antitoxin. Although not as convenient as the i.p. method for routine use to detect botulinum toxin, the i.m. method has characteristics which could make it a useful supplement to the presently accepted i.p. procedure.
Liquid Nitrogen Cryo-Impacting: a New Concept for Cell Disruption
Authors: Smucker Richard A. , Pfister Robert M.
Published: December 2020

High-efficiency disruption of bacteria can be accomplished in 2 or more min by the new procedure of liquid nitrogen cryo-impacting. Release of the dipicolinic acid-Ca
2+
chelate paralleled the breakage of
Bacillus megaterium
endospores. Lactate dehydrogenase activity was much better in supernates from liquid nitrogen cryo-impacting-broken
Escherichia coli
cells than in those from sonically treated and broken
E. coli
cells.
Effect of Temperature on the Sterilization of Isopropyl Alcohol by Liquid Propylene Oxide
Authors: Hart A. , Ng S. N.
Published: December 2020

Liquid propylene oxide added to a solution of isopropyl alcohol and incubated at different temperatures markedly reduced the time required to sterilize the alcohol solution.
γ-Aminobutyric Acid Pathway and Modified Tricarboxylic Acid Cycle Activity During Growth and Sporulation of
Bacillus thuringiensis
Authors: Aronson John N. , Borris David P. , Doerner Jeffrey F. , Akers Evelyn
Published: December 2020

Enzymatic analyses of
Bacillus thuringiensis
extracts suggested that a modified Krebs tricarboxylic acid cycle (without α-ketoglutarate dehydrogenase) can operate during sporulation in conjunction with the glyoxylic acid cycle and the γ-aminobutyric acid pathway.
Purification and Characterization of Extracellular Proteinases of
Aspergillus oryzae
Authors: Kundu A. K. , Manna S.
Published: December 2020

The extracellular proteinases of
Aspergillus oryzae
EI 212 were separated into two active fractions by (NH
4
)
2
SO
4
and ethanol fractionation followed by diethyl-aminoethyl-Sephadex A-50 and hydroxyapatite chromatography. The molecular weight was estimated by gel filtration to be about 70,000 and 35,000 for proteinases I and II, respectively. Optimum pH for casein and hemoglobin hydrolysis was 6.5 at 60 C for proteinase I and 10.0 at 45 C for proteinase II, and for gelatin hydrolysis it was 6.5 at 45 C for both enzymes. The enzymes were stable over the pH range 6 to 8 at 30 C for 60 min. The enzyme activity for both the proteinases was accelerated by Cu
2+
and inhibited by Fe
2+
, Fe
3+
, Hg
2+
, and Ag
+
. Halogenators (e.g.,
N
-chlorosuccinimide) and diisopropyl fluorophosphate inhibited proteinase II. Sulfhydryl reagents such as
p
-chloromercuribenzoate and iodoacetate inhibited proteinase I. Sulfhydryl compounds accelerated the action of both enzymes.
Enumeration of High Numbers of Bacteria Using Hydrophobic Grid-Membrane Filters
Authors: Sharpe Anthony N. , Michaud Gregory L.
Published: December 2020

Printing a wax grid on a conventional membrane filter yields a device functioning as a most probable number apparatus (MPN), used at a single dilution but with a very large number of growth compartments (e.g., 3,650). By restraining the lateral spread and confluence of colonies, the hydrophobic grid-membrane filter (HGMF) allows growth- or colony-forming units (GU) to be resolved at levels far above those which produce an uncountable lawn on a conventional membrane filter. It also eliminates the size variation of normal bacterial colonies. As a result, the HGMF can give more accurate estimates of the concentration of GU. The method by which grid-cell count observations can be used to obtain MPN estimates of the number of GUs is described, and estimates obtained using the MPN method on the HGMF are compared with those resulting from conventional colony count procedures on membrane filters. A linear relation was observed between MPNGU and the number of GUs, at levels up to 30,000 GUs, for pure cultures of bacteria and for samples of natural waters. The HGMF has great potential for reducing the labor required in quantitative microbiology, since it allows, with one filter, enumeration of microorganisms over a very large concentration range and therefore reduces the need to make dilutions.
Detection of
Lactobacillus acidophilus
in Feces of Humans, Pigs, and Chickens
Authors: Gilliland S. E. , Speck M. L. , Morgan C. G.
Published: December 2020

Lactobacilli in fecal material from humans, pigs, and chickens were enumerated on lactobacillus selective agar (LBS). In all samples, higher numbers of lactobacilli were detected when plates were incubated in a system flushed with CO
2
rather than in air. Much higher numbers of bacteria from human feces were detected when the LBS agar plates were incubated anaerobically in a hydrogen-carbon dioxide atmosphere (GasPak) than when incubated in CO
2
. The bacteria from human feces isolated on LBS agar incubated anaerobically were predominately bifidobacteria. Cultures from all three sources isolated on LBS agar incubated under CO
2
were lactobacilli, including
Lactobacillus acidophilus
. Differences were observed in biochemical characteristics of some of the
L. acidophilus
isolated from all three sources. Guanine plus cytosine base ratios of deoxyribonucleic acid isolated from
L. acidophilus
cultures from humans were lower, in most cases, than those from pigs and chickens.
Effects of an Antibacterial Soap on the Ecology of Aerobic Bacterial Flora of Human Skin
Authors: Voss J. G.
Published: December 2020

The effects of ad lib use of an antibacterial soap containing 1.0% trichlorocarbanilide and 0.5% trifluoromethyldichlorocarbanilide on the bacterial flora of six skin sites of 132 subjects were measured by comparison with the flora of 93 control subjects who avoided the use of topical antibacterials. Each subject was examined once. The test soap produced significant reductions in geometric mean counts of the total aerobic flora on the back, chest, forearm, calf, and foot; counts were also reduced in the axilla, but not to a significant extent. The overall reduction by the test soap on all sites was 62% (
P
< 0.001). Neither age nor sex influenced the effect of the soap on the flora. The antibacterial soap also reduced the prevalence of
Staphylococcus aureus
on the skin, mostly by virtually eliminating it from areas other than the axilla. Partial inhibition of the gram-positive flora was not accompanied by an increase in gram-negative species. The latter were found principally in the axilla;
Klebsiella pneumoniae
and
Enterobacter aerogenes
were the species most frequently found.
Enzymatic Transformation of Morphine by Hydroxysteroid Dehydrogenase from
Pseudomonas testosteroni
Authors: Liras Paloma , Kasparian Stephen S. , Umbreit Wayne W.
Published: December 2020

Enzyme preparations from
Pseudomonas testosteroni
containing α- and β-hydroxysteroid dehydrogenases catalyzed the oxidation of morphine and codeine by nicotinamide adenine dinucleotide. Morphine was converted in relatively low yield into 14-hydroxymorphinone probably via morphinone as an intermediate. Codeine was converted to codeinone and 14-hydroxycodeinone. Only the conversions at the 6-position were carried out by the hydroxysteroid dehydrogenase. Hydroxylation at the 14-position did occur spontaneously (or enzymatically with a contaminating enzyme) after oxidation at the 6-position.
Optimum Membrane Structures for Growth of Coliform and Fecal Coliform Organisms
Authors: Sladek K. J. , Suslavich R. V. , Sohn B. I. , Dawson F. W.
Published: December 2020

The purpose of this study was to determine the optimum membrane filter structure and characteristics for recovery of coliform organisms. Additionally, other factors such as sterilization method and membrane composition were examined. Fecal coliform growth tests with varied samples indicated that the most critical factor in recovery was surface pore morphology and not other factors previously suspected. Fecal coliform counts showed a dramatic increase, with increasing surface opening sizes. Membrane structures with surface openings large enough to surround the entrapped bacteria are required for optimum growth of fecal coliform organisms. Maximum fecal coliform recoveries are obtained using membranes composed of mixed esters of cellulose exhibiting a surface opening diameter of 2.4 μm and a retention pore size of 0.7 μm.
Bactericidal Effect of Hydrogen Peroxide on Spacecraft Isolates
Authors: Wardle M. D. , Renninger G. M.
Published: December 2020

Solutions of 3, 10, and 15% hydrogen peroxide were found to have pronounced bactericidal effects, as a function of time of exposure, on sporeformers and non-sporeformers isolated from spacecraft.
Microbial Utilization of
Pinus radiata
Bark
Authors: Updegraff David M. , Grant W. D.
Published: December 2020

A screening program using suspensions of ground bark in mineral salts media, or extracts prepared from ground bark by treating with hot water, sulfuric acid, ammonium hydroxide, or sodium hydroxide, yielded more than 200 pure cultures of fungi, yeasts, and bacteria. Only 38 of these gave good growth on liquid bark media. All were filamentous fungi, although many bacteria and yeasts were among the cultures that failed to give appreciable growth. Species of
Penicillium, Scopulariopsis, Aspergillus, Trichoderma, Cladosporium
, and
Fusarium
were among the most actively growing cultures. Cell biomass yields, as measured by cell nitrogen determinations, were too low for economic production of single cell protein.
Method for Collecting Naturally Occurring Airborne Bacterial Spores for Determining Their Thermal Resistance
Authors: Puleo J. R. , Favero M. S. , Oxborrow G. S. , Herring C. M.
Published: December 2020

The ability to determine the thermal resistance of naturally occurring air borne bacterial spores associated with spacecraft and their assembly areas has been hindered by lack of an effective collecting system. Efforts to collect and concentrate spores with air samplers or from air filters have not been successful. A fallout method was developed for this purpose and tested. Sterile Teflon ribbons (7.6 by 183 cm) were exposed in pertinent spacecraft assembly areas and subsequently treated with dry heat. Thermal inactivation experiments were conducted at 125 and 113 C. Heating intervals ranged from 1 to 12 h at 125 C and 6, 12, 18, and 24 h at 113 C. Eight hours was the longest heating time yielding survivors at 125 C, whereas survivors were recovered at all of the heating intervals at 113 C. D
125C
values were calculated using the fractional-replicate-unit-negative technique of Pflug and Schmidt (1968) and ranged from 25 to 126 min. This variation indicated that the most probable number of survivors at each heating interval did not fall on a straight line passing through the initial spore population. However, the most-probable-number values taken alone formed a straight line suggesting logarithmic thermal destruction of a subpopulation of spores with a D
125C
value of 6.3 h.
Growth of
Staphylococcus
and
Salmonella
on Frankfurters With and Without Sodium Nitrite
Authors: Bayne Henry G. , Michener H. David
Published: December 2020

Conventional and nitrite-free frankfurters in loosely wrapped packages were compared as to their ability to support growth of
Salmonella, Staphylococcus
, and their naturally occurring spoilage flora at 7 C (simulating refrigerated storage) and 20 C (simulating possible temperature abuse). At 7 C
Salmonella
did not grow in either type of frankfurter;
Staphylococcus
and the natural spoilage flora sometimes grew more rapidly in the absence of nitrite, but the difference was not significant. At 20 C growth of
Salmonella, Staphylococcus
, and of the spoilage flora was, at most, only slightly faster on nitrite-free frankfurters.
Salmonella
was not suppressed in broth culture experiments at the pH and nitrite content found in frankfurters. Although either type of frankfurter can become hazardous due to growth of
Salmonella
or
Staphylococcus
, no unusual or additional hazard resulted from the omission of nitrite from frankfurters.
Nonautotrophic
Thiobacillus
in Acid Mine Water
Authors: Myers Paula S. , Millar W. N.
Published: December 2020

Nonautotrophic thiobacilli were isolated from the acidic water of a coal mine. Based on their mixotrophic physiology, the isolates are regarded as strains of
Thiobacillus perometabolis
.
Safe, Convenient Pipetting Station
Authors: Songer J. R. , Braymen D. T. , Mathis R. G.
Published: December 2020

A simple convenient pipetting station is described that eliminates the need for mouth pipetting. Necessary components, fabrication procedures, and operating techniques are given.
Heat resistance of ileal loop reactive Bacillus cereus strains isolated from commercially canned food
Authors: Bradshaw J G , Peeler J T , Twedt R M
Published: December 2020

Sporeformers isolated from a commercially canned food were identified as Bacillus cereus, lactose-positive variants. The thermal resistance of spore crops produced from each of two representative cultures was determined in 0.067 M phosphate buffer at pH 7.0. The D121.1 values for one isolate were approximately 0.03 min (z = 9.9C), whereas the D121.1 values for the other isolate were 2.35 min (z = 7.9 C). Thermal inactivation results for heat-stressed isolates from each strain showed no significant alteration in heat resistance from that of the two parent spore crops. Both isolates were reactive when injected into the ligated rabbit ileum.
Effects of three environmental variables on sulfate uptake by aerobic bacteria
Authors: Monheimer R H
Published: December 2020

The effects of various concentrations of sulfate, organic sulfur, and organic carbon on sulfate uptake by aerobic bacteria were studied using pure cultures growing in a defined medium. Cultures of Pseudomonas fluorescens and Corynebacterium striatum took up sulfate faster when young, but sulfate uptake by Serratia marcescens was faster in older cultures. Organic sulfur was found to decrease sulfate uptake, but at concentrations somewhat higher than occurs in most natural freshwater ecosystems. Low levels of sulfate can theoretically directly limit bacterial biomass production but such limitation probably does not occur in natural systems. Evidence is presented which indirectly links the uptake of sulfate and organic carbon, adding credibility to the proposal that sulfate uptake can be used as an indicator of microbial biomass production in freshwater ecosystems.
Lyophilization of
Pasteurella pestis
Authors: Heckly R. J. , Anderson A. W. , Rockenmacher M.
Published: December 2020

Images

Figure 1
Antibiotics as Preservatives for Industrial Materials
Authors: Ross S. H.
Published: December 2020

Images

Figure 1
Sterilization of Regenerated Collagen Sutures with β-Propiolactone
Authors: Ball Edwin L. , Dornbush Albert C. , Sieger George M. , Stirn F. E. , Vitucci James C. , Weidenheimer Joseph F.
Published: December 2020

Data are presented to show that β-propiolactone when properly applied is a very effective agent for sterilization of regenerated collagen sutures. The chemical sterilization is accomplished with little or none of the loss in strength encountered with heat sterilization. The finished sterile suture is obtained without any harmful residue that might be detrimental to the patient.
A Pigment-producing Spoilage Bacterium Responsible for Violet Discoloration of Refrigerated Market Milk and Cream
Authors: Seitz Eugene W. , Elliker P. R. , Sandine W. E.
Published: December 2020

A psychrophilic strain of bacteria identified as
Chromobacterium lividum
was established as the causative agent of an outbreak of violet discoloration in refrigerated, pasteurized retail milk and cream.

The organism was rod-shaped, gram-negative, and produced viscid colonies with abundant violet pigment on Tryptone glucose yeast extract agar. Growth was abundant at 4 C but none occurred at 37 C. Growth in milk was characterized by a dark violet ring at the surface after a few days, and the deep violet color gradually extended through the product in older cultures. Some proteolysis occurred. The pigment appeared to be similar to that of other known species of
Chromobacterium
and assisted in identification of the genus of the causative organism.

The isolated strain of
C. lividum
was destroyed by exposure to 56 C for 5 min which suggested postpasteurization contamination as the source of the spoilage organism in commercial milk and cream.
Time-Temperature Effects on Salmonellae and Staphylococci in Foods
Authors: Angelotti Robert , Foter Milton J. , Lewis Keith H.
Published: December 2020

Thermal death time studies were conducted at 5 F intervals from 130 to 150 F with strains of salmonellae and enterotoxigenic staphylococci. Heat-resistant
Salmonella senftenberg
strain 775W,
Staphylococcus aureus
strains 196E and Ms149, and non-heat-resistant
Salmonella manhattan
were studied in custard, chicken à la king, and ham salad.

The
F
140
values (minutes of exposure at 140 F required to effect 100% destruction) were as follows:
S. senftenberg
775W in custard 78, and chicken à la king 81.5;
S. manhattan
in custard 19, and chicken à la king 3.1;
S. aureus
196E in custard 59, and chicken à la king 47;
S. aureus
Ms149 in custard 53, and chicken à la king 40.

The end points of survival-kill at all the test temperatures for both salmonellae and staphylococci in ham salad were considerably less than for the other foods studied.

D
140
values (minutes of exposure at 140 F required to effect a 90% reduction in numbers) were also calculated from the data and presented.

Values for

z
F

and

z
D

(slope of the thermal-death-time and decimal-reduction-time curves) are also presented and discussed in relation to type of food, organism, and temperature.

These data indicate that heating perishable foods of the type studied to 150 F and holding every particle of food at this temperature for at least 12 min reduces 10 million or less salmonellae or staphylococci per gram to nondetectable levels.

The same degree of destruction is achieved in similarly contaminated foods when held at 140 F for 78 to 83 min.

On the basis of the calculation procedures employed, it is estimated that 45-min exposure at 140 F would be necessary to reduce 1,000 organisms per gram to nondetectable levels.
Cacao Fermentation
Authors: Martelli H. L. , Dittmar H. F. K.
Published: December 2020

Cacao beans must be subjected to fermentation before they are used in making chocolate, and their commercial value is related to a proper procedure.
Saccharomyces rosei, Hansenula anomala, Pichia fermentans, Pichia membranaefaciens
, and
Trichosporon cutaneum
were found in fermenting cacao beans. All species isolated during the investigation grew on cacao pulp, but only
S. rosei, H. anomala
, and
P. fermentans
exhibited fermenting capacity on the sugars of cacao pulp. Species of the genus
Saccharomyces
were identified as the agents responsible for the alcoholic phase of the cacao fermentation.
16α-Hydroxy Steroids
Authors: Goodman Joseph J. , Smith Leland L.
Published: December 2020

9α-Fluorohydrocortisone is hydroxylated by
Streptomyces roseochromogenes
in the 16α-, the 2β-, and in both the 16α- and 2β- positions. 16α-Hydroxylation appears to be the more predominant and rapid pathway of transformation. The degree of 2β-hydroxylation is dependent upon the strain used and may be increased to the point of its being a major route or virtually eliminated by the proper selection of isolates.
Comparison of Tellurite Resistance and Tetracycline Resistance among the Enterococci
Authors: Appleman M. D. , Heinmiller I. M.
Published: December 2020

A correlation was found to exist between tellurite and tetracycline resistance in the enterococci.
Evaluation of Factors Affecting Survival of
Escherichia coli
in Sea Water
Authors: Carlucci A. F. , Scarpino P. V. , Pramer David
Published: December 2020

The bactericidal action of sea water was measured as the difference in survival of cells of
Escherichia coli
in untreated and autoclaved portions of water samples. The beneficial effect of sterilization by heat on the survival of
E. coli
in sea water varied with season and was most marked during summer months, however, the magnitude of the effect differed greatly from sample to sample. The more obvious and commonly suggested explanations for the bactericidal action of sea water were tested experimentally. The pH and salinity of sea water were changed by autoclaving, but the direction of the former was detrimental rather than beneficial and the significance of the latter was not clarified. The survival of cells of
E. coli
in filtered portions of some water samples was greater than that in untreated portions and equal to that in autoclaved portions, indicating that predators and competitors removed by filtration had contributed significantly to the rapid death of the bacterium in the untreated water. However, in the majority of samples tested, survival of
E. coli
in autoclaved water was considerably greater than survival in filtered water.

The possibility that the beneficial effect of autoclaving over and above that of filtration resulted from inactivation or destruction by heat of bacteriophages and thermolabile toxic substances such as antibiotics was considered. Moreover, the suggestion was tested that the increased survival of
E. coli
in autoclaved sea water was due to the ability of heat to disrupt and degrade microbial cells and thermolabile compounds and, thereby, to cause an increase in concentration of available nutrients in sea water. It was concluded that the bactericidal action of sea water is not explicable in terms of the destruction or inactivation by heat of bacteriophages or antibiotics. Although added organic matter influenced the survival of
E. coli
, the test organism was not an effective competitor in sea water and the nutrient levels required to offset the bactericidal action were excessive.

Artificial sea water was demonstrated to exert a bactericidal action comparable to that of natural sea water. Low levels of cysteine which favor survival of
E. coli
in natural sea water had a similar effect in artificial sea water. Nevertheless, it is not at this time possible to conclude that the factors responsible for the bactericidal action of artificial sea water are identical with those responsible in natural sea water.
Studies on the Thermal Destruction of
Escherichia coli
in Milk and Milk Products
Authors: Read R. B. , Schwartz Charles , Litsky Warren
Published: December 2020

Escherichia coli
(ATCC no. 9637) was shown to have mean
D
values (slope of destruction rate curve) of 28.2, 5.1, 1.3, 0.00195, 0.00100, 0.00055, 0.00029, and 0.00016 min in milk at temperatures of 125, 130, 135, 168, 170, 172, 174, and 176 F, respectively. The mean
D
values for this organism in chocolate milk were 32.2, 10.4, 2.6, 0.00265, 0.00133, 0.00069, 0.00035, and 0.00028 min at respective temperatures of 125, 130, 135, 168, 170, 172, 174, and 176 F. Mean
D
values of 34.4, 10.0, 3.5, 0.00093, 0.00080, 0.00068, 0.00043, and 0.00036 min were found in cream for respective temperatures of 125, 130, 135, 168, 170, 172, 174, and 176 F. In ice cream mix the organism was found to have mean
D
values of 39.3, 15.2, 5.1, 0.00147, 0.00120, 0.00078, 0.00070, and 0.00053 min for temperatures of 125, 130, 135, 170, 172, 174, 176, and 178 F, respectively. The slopes of the thermal death time curves were found to be 10.2, 10.2, 10.0, and 10.3 F for this organism in milk, chocolate milk, 40% fat cream, and ice cream mix, respectively.
Observations on a Laboratory Method for Submerged Acetic Fermentation
Authors: Lopez Anthony , Johnson L. W. , Wood C. B.
Published: December 2020

Submerged acetic fermentation experiments were performed for the purpose of determining the conditions under which this type of fermentation should be conducted under laboratory conditions. The apparatus used consisted of a set of glass tubes provided with air spargers.

Acetobacter acetigenum
was found to be the most suitable bacterium among six
Acetobacter
compared under submerged acetic fermentation conditions in a synthetic medium. Statistically significant different rates of fermentation were observed in acetators that were identical in construction, fermentation medium, and aeration characteristics.

Extremely long growth lag periods and complete absence of growth were often observed when starting fermentations. The causes of this behavior were investigated. It was found that it was not produced by lack of nutrients or by presence of a bacteriophage. Different kinds of bacterial starters were studied and compared. Cultures maintained in a liquid medium were reliable starters with a short growth lag period. Liquid medium cultures maintained their good starter characteristics after periods of storage of up to 11 weeks at 40 F (4 C).
A Practical Approach to Evaluation of the Germicidal Efficiency of a General Purpose Military Disinfectant
Authors: Rogers M. R. , Maher J. T. , Kaplan A. M.
Published: December 2020

The bactericidal activity of a general purpose disinfectant consisting of 25% sodium-
o
-phenylphenolate and 75% sodium-4- and 6-chloro-2-phenylphenolate was evaluated by a simulated in-use, surface-square dilution method. Common floor (asphalt, rubber, and unglazed tiles) and wall (stainless steel tile, ceramic tile, and painted wood) surfaces of various porosities and compositions were selected to simulate actual-use conditions.

The method used consisted of inoculating the surfaces of 1-in. square sections of floor and wall covering with a test organism, air-drying the inoculated surface, applying the disinfectant, allowing it to act for 10 min, and recovering the survivors by plating. Confirmatory results of the standard phenol coefficient and use-dilution tests indicated 700 ppm of the disinfectant to be a safe use concentration. The in-use surface-square dilution studies have shown that this is a more than adequate safe concentration for stainless steel, both glazed and unglazed ceramic tile, and nonwaxed surface of asphalt tile. However, concentrations ranging between 2,500 and 6,000 ppm for plastic-fortified rubber tile, 1,500 and 2,000 ppm for waxed asphalt tile, and 2,000 ppm for painted wood were required to achieve 99.9% reduction of either
Salmonella choleraesuis
or
Salmonella schottmuelleri
. These results indicate that a disinfectant concentration derived from the Association of Official Agricultural Chemists use-dilution test cannot always be relied upon to provide a dependable index to actual safe use-dilution when a disinfectant is supplied to certain wall or floor surfaces.
Oxytetracycline Formation by
Streptomyces rimosus
in Chemically Defined Media
Authors: Zygmunt W. A.
Published: December 2020

Details in the fermentation of oxytetracycline in a synthetic medium with
Streptomyces rimosus
have been presented. In these studies, an organic nitrogen source was shown to be essential for the production of significant amounts of antibiotic activity. Of the amino acids tested, aspartic acid, proline, threonine, valine, and β-alanine were utilized well for both growth and antibiotic production. Markedly different fermentation patterns were observed with aspartic acid and β-alanine. Glycerol and glucose supported antibiotic yields superior to those found with other carbohydrates tested. Short chain organic acids were not effectively utilized for growth in the absence of a readily fermentable carbohydrate.
Preparation of Purified Polysaccharides from
Rhizobium
Authors: Davis R. J. , Clapp C. E.
Published: December 2020

A method is described for the preparation of purified polysaccharides from strains of
Rhizobium
in quantities large enough so that with an exhaustive purification scheme enough product is recovered for various characterization purposes. When steps in the purification process are eliminated, much larger amounts of crude gum are obtained.

Organisms were grown in liquid medium and the crude gum was precipitated along with the bacterial cells by a quaternary ammonium complexing agent. This precipitate was dissolved in salt solution, reprecipitated with ethanol or ethanol-acetone mixtures several times, followed by pressure filtration with membrane filters.

The same procedure should be applicable to commercial scale production in large fermentors if a use for the gum could be shown. The method also should be suitable for other organisms with similar growth habits.
Mixtures of Quaternary Ammonium Compounds and Long-chain Fatty Acids as Antifungal Agents
Authors: Kull F. C. , Eisman P. C. , Sylwestrowicz H. D. , Mayer R. L.
Published: December 2020

The influence of undecylenic acid on the fungistatic effect of phenoxyethyldimethyldodecylammonium bromide (Domiphen bromide) against
Trichophyton mentagrophytes
was investigated. The unsaturated fatty acid was found to enhance the fungistatic activity of Domiphen bromide against this organism. The ratio of concentrations of these agents has a marked influence on the results of in vitro tests for antifungal action resulting in a completely different effect than heretofore noted in combination experiments against bacteria. The enhancing phenomenon is not particular to
T. mentagrophytes
, it was observed also with
Candida albicans
.
Occurrence of Enterococci: Bud, Blossom, and Soil Studies
Authors: Mundt J. Orvin
Published: December 2020

The occurrence of enterococci (group D streptococci) on buds and flowers of plants and in soils has been studied. They were recovered from 27.5% of the flowers of seven species of plants, and from 6.8% of the buds of the same plants. They were recovered from 34% of the flowers of nonagricultural plants, from 32.2% of the flowers of ten species of agricultural dicotyledonous plants, and from 10.4% of the flowers of five species of grasses and cereals. The enterococci were invariably present or invariably absent from all samples taken from very few species. They occurred in small numbers on enclosed tassels and silks of corn of 22 of 60 samples, and in greater numbers on 90% or more of these after their floral parts had emerged. Interposition of a mechanical barrier reduced the incidence of recovery from flowers. The occurrence in soil, generally at a low level of population, may be correlated with occurrence on the plant growing on the soil or with nearby enterococcal-bearing plants.

It is concluded that enterococci may be regarded as temporary residents on plants, capable of limited reproduction, and that they are disseminated among plants by the action of insects and wind, and spread to the ground by these agencies, gravity, and rain.
Replication of Variola Virus in Suspended Cultures of Mammalian Cells
Authors: Mika Leonard A. , Pirsch James B.
Published: December 2020

The studies reported here describe the successful propagation of variola virus in spinner cultures of mammalian cells, and the factors which influence its growth. Five established cell lines were used for the propagation of variola virus in a spinner culture system. Low doses of virus did initiate an infection but virus yields did not approach those obtained when an intermediate inoculum was used. Although the nonviable cell population remained low during the course of infection with an intermediate amount of virus, with an inoculum of 10
5
infectious units per ml or higher, the percentage of nonviable cells increased rapidly and by the sixth day after infection the population was totally nonviable. Intracellular replication of variola virus occurred early and rapidly in a spinner culture of guinea pig lung cells, whereas the liberation of virus into the suspending medium was a more gradual process. Several complete medium changes tend to maintain a suitable environment for the infected cell culture resulting in fairly high and constant viral titers over a period of 7 days.
Algicidal and Sanitizing Properties of Armazide
Authors: Antonides H. J. , Tanner W. S.
Published: December 2020

Algicidal and sanitizing properties of Armazide, a new swimming pool additive, consisting of 12% w/v each of dodecylamine hydrochloride, trimethyl alkyl ammonium chloride, and methyl alkyl dipolyoxypropylene ammonium methyl sulfate in solution, were evaluated by laboratory techniques against algae and sewage. Results indicated it to be highly effective in low concentrations especially in conjunction with low concentrations of chlorine. Swimming pool field tests were found to confirm the laboratory findings. Various treatment levels and methods are described for swimming pools using treatments based upon the actual condition of the pool and water. The use of the product permitted a reduction in chlorine residual in pools resulting in greatly reduced requirements for chlorinating chemicals along with absence of irritation, odor, and other undesirable results usually associated with standard pool chlorination methods.
Factors Affecting Filamentous Growth of
Sphaerotilus natans
Authors: Gaudy Elizabeth , Wolfe R. S.
Published: December 2020

Filamentous growth in cultures of
Sphaerotilus natans
can be measured and compared with total growth by a standardized procedure of winding filaments around an inoculating needle. Filaments and residual growth are then separately washed on Millipore filters, dried, and weighed. This method has been used to study changes in the growth habit of
S. natans
elicited by changes in the concentration of nutrients in the medium. The concentration of peptone, in a medium containing a sugar, phosphate buffer, and inorganic salts, has a much greater effect on the proportion of filamentous growth than does the nature or concentration of the carbon source or the concentration of phosphate buffer. Filament formation is significantly inhibited by concentrations of peptone greater than 0.25%; further increases in peptone concentration stimulate the production of large amounts of capsular material. Increasing the concentration of phosphate buffer to 0.05 M almost completely inhibits growth of
S. natans
.
A collection of strains containing genetically linked alternating antibiotic resistance elements for genetic mapping of Escherichia coli
Authors: Singer M , Baker T A , Schnitzler G , Deischel S M , Goel M , Dove W , Jaacks K J , Grossman A D , Erickson J W , Gross C A
Published: December 2020

We present a collection of 182 isogenic strains containing genetically linked antibiotic resistance elements located at approximately 1-min intervals around the Escherichia coli chromosome. At most positions both Tn10 (Tetr) and TN10kan (Kanr) elements are available, so that the collection contains a linked set of alternating antibiotic resistance markers. The map position of each insertion has been aligned to the E. coli genetic map as well as to the Kohara ordered clone bank. These strains are designed to be used in a rapid two-step mapping system in E. coli. In the first step, the mutation is localized to a 5- to 15-min region of the chromosome by Hfr mapping with a set of Hfr strains containing either Tn10 or Tn10kan elements located 20 min from their respective origins of transfer. In the second step, the mutation is localized to a 1-min region by P1 transduction, with a collection of isogenic insertion strains as donors. We discuss the uses of this collection of strains to map and eventually to clone a variety of mutations in E. coli.