bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative dose-survival curves of representative Clostridium botulinum type F spores with type A and B spores
Authors: Anellis A , Berkowitz D
Published: January 2020

Radiation survival data of proteolytic (Walls 8G-F) and non-proteolytic (Eklund 83F) type F spores of Clostridium botulinum were compared with dose-response data of radiation-resistant type A (33A) and B (40B) spores. Strain Eklund 83F was as resistant as strain 33A, whereas strain Walls 8G-F was the most sensitive of the four strains tested. The methods suggested for computing both an initial shoulder and a D value for the dose-survival curves yielded results comparable to the graphic techniques used to obtain these two parameters.
Agar plate screening procedure for cyclic adenosine 3',5'-monophosphate and inhibitors of cyclic nucleotide phosphodiesterase
Authors: Somers P J , Higgens C E
Published: January 2020

A procedure is described for the semiquantitative measurement of cyclic adenosine 3',5'-monophosphate (cAMP) and detection of inhibitors of cAMP phosphodiesterase by an agar plate test. The assay organism was an adenyl cyclase-deficient mutant derived from Escherichia coli HfrH. In the presence of an acid base indicator, acid production from barbohydrate metabolism was observed as a yellow zone around filter paper disks containing cAMP. Since yellow zone formation reflects the presence of cAMP, a phosphodiesterase inhibitor can be detected indirectly by the presence of a yellow zone on assay plates from a reaction mixture of an inhibitor, phosphodiesterase, and cAMP. Three known cyclic nucleotide phosphodiesterase inhibitors were active against beef brain phosphodiesterase in this system.
Stimulation of the growth and respiration of a methylotrophic bacterium by morphine
Authors: Romeo J , Scheraga M , Umbreit W W
Published: January 2020

The growth of a pseudomonad on methanol was stimulated by the presence of morphine (or codeine) in the medium. The drug appeared to influence the amount of growth rather than its rate. Respiration of resting cells on a variety of substrates was stimulated by adding morphine. This report appears to be the first case of a microorganism whose growth and respiration is stimulated by an opiate.
Spontaneous mutation of polysaccharide production in Alcaligenes faecalis var. myxogenes 10C3
Authors: Amemura A , Hisamatsu M , Harada T
Published: January 2020

Alcaligenes faecalis var. myxogenes 10C3, which produces large amounts of succinoglucan and small amounts of curdlan, was genetically unstable and mutated spontaneously to a form producing more curdland than succinoglucan when stocked on nutrient agar slants. The mutation occurred in the absence of cell division when the cells were incubated in saline and was enhanced by treatment with N-methyl-N'-nitro-N-nitrosoguanidine, ethyl methane sulfonate, or ultraviolet light. Mutant strains were genetically stable and did not revert spontaneously for at least 1 year when stocked on nutrient agar slants.
Value of the K+ salt of carageenan as an agar substitute in routine bacteriological media
Authors: Lines A D
Published: January 2020

The K+ salt of carageenan has no distinct advantages as a gelling agent, but it compared favorably with agar in most of the media tested. The difficulty involved in the preparation of blood plates and the results obtained with this medium prohibit its complete acceptance as a substitute for agar in routine solid media. However, it could be a suitable substitute for agar in all other routine bacteriological media.
Discovery of an agent in wastewater sludge that reduces the heat required to inactivate reovirus
Authors: Ward R L , Ashley C S
Published: January 2020

An agent that causes heat inactivation of reovirus to occur at reduced temperatures has been found in both raw and anaerobically digested sludge. This agent is originally associated with sludge solids but can be washed from these solids by blending with water. The activity of the agent was considerably greater in alkaline than in acid solutions, probably because it is insoluble at low pH. The agent was shown to be nonvolatile and heat stable up to 300 degrees C but was inactivated within 30 min at 400 degrees C. The rate of heat inactivation of reovirus by the agent was found to occur in a bimodal fashion and to be relatively rapid, even at 35 degrees C. Finally, it was found that this agent did not accelerate heat inactivation of poliovirus, but instead may be the component of sludge previously found to protect poliovirus against inactivation by heat.
Increase in arginine and citrulline production by 6-azauracil-resistant mutants of Bacillus subtilis
Authors: Kato J , Kisumi M , Takagi T , Chibata I
Published: January 2020

In the arginine producer AHr-5, an L-arginine hydroxamate-resistant mutant of Bacillus subtilis, accumulation of N8-acetyl-L-ornithine increased as the level of L-arginine accumulation increased in the medium containing L-glutamic acid. Ornithine carbamoyltransferase of this strain was genetically derepressed. These results suggested that carbamoylphosphate might be deficient in vivo. With the intention to increase endogenous carbamoylphosphate, pyrimidine analogs inhibiting growth were selected and the mutants resistant to these compounds were derived from the AHr-5 mutant. Of the resistant mutants derived, the 6-azauracil-resistant mutant AAr-9 produced 28 mg of L-arginine per ml, which corresponded to more than twofold the amount produced by the parent strain. Derivation of an arginine-requiring mutant from the double-resistant mutant AAr-9 provides a new advantageous method for the production of L-citrulline. The increase in arginine and citrulline production is discussed.
Dialysis Continuous Process for Ammonium-Lactate Fermentation of Whey: Experimental Tests
Authors: Stieber R. W. , Coulman G. A. , Gerhardt Philipp
Published: January 2020

Laboratory experiments were conducted to validate theoretical predictions describing a dialysis continuous process for the fermentation of whey lactose to ammonium lactate, in which the fermentor contents are poised at a constant pH by adding ammonia solution and dialyzed through a membrane against water. Dried sweet-cheese whey was rehydrated to contain 230 mg of lactose per ml, supplemented with 8 mg of yeast extract per ml, charged into a 5-liter fermentor without sterilization, adjusted in pH (5.3) and temperature (44°C), and inoculated with
Lactobacillus bulgaricus.
The fermentor and dialysate circuits were connected, and steady-state conditions were established. A series of such conditions was managed nonaseptically for 94 days to study the process and to demonstrate efficiency and productivity. As time progressed, the fermentation remained homofermentative and increased in conversion efficiency, although membrane fouling necessitated dialyzer cleaning about every 4 weeks. With a retention time of 19 h, 97% of the substrate was converted into products. Relative to nondialysis continuous or batch processes for the fermentation, the dialysis continuous process enabled the use of more concentrated substrate, was more efficient in the rate of substrate conversion, and additionally produced a second effluent of less concentrated but purer ammonium lactate.
Preparation of mutants of Trichoderma reesei with enhanced cellulase production
Authors: Montenecourt B S , Eveleigh D E
Published: January 2020

The development of an agar plate screening technique has allowed the isolation of a range of mutants of Trichoderma reesei capable of synthesizing cellulase under conditions of high catabolite repression. The properties of one of these mutants (NG-14) is described to illustrate the use of this technique. NG-14 produced five times the filter paper-degrading activity per ml of culture medium and twice the specific activity per mg of excreted protein in submerged culture when compared with the best existing mutant, QM9414. NG-14 also showed enhanced endo-beta-glucanase and beta-glucosidase production. Although these mutants were isolated as cellulase producers in the presence of 5% glycerol on agar plates, in similar liquid medium, NG-14 exhibits only partial derepression of the cellulase complex. Since the proportions of filter paper activity, endo-beta-glucanase, and cellobiase were not the same in mutants NG-14 and QM9414, and the yields of each enzyme under conditions repressive for cellulase synthesis were different, differential control of each enzyme of the cellulase complex is implied. These initial results suggest that the selective technique for isolating hyper-cellulase-producing mutants of Trichoderma will be of considerable use in the development of commercially useful cellulolytic strains.
Antialgal substances for iodine-disinfected swimming pools
Authors: Nilson E L , Unz R F
Published: January 2020

Forty substances were tested for antialgal activity against Chlorella pyrenoidosa (Wis. 2005) and Phormidium inundatum (Wis. 1093). C. pyrenoidosa exhibited greater resistance to adverse effects of test compounds than did P. inundatum. Although several structurally unrelated compounds were inhibitory to both alga species, even at an initial concentration of 1.0 mg/liter, methylthio-s-triazines, ametryne, prometryne, and terbutryne, at 0.1 mg/liter, restricted growth to less than 25% of control (untreated) cultures. The methylthio-s-triazines were virtually chemically unreactive with free iodine. Inhibition of Staphylococcus aureus by free iodine dosages of 0.25, 0.5, 0.75, and 1.0 mg/liter was unaffected by the presence of 2.0 mg of terbutryne per liter.
Cryogenic gamma irradiation of prototype pork and chicken and antagonistic effect between Clostridium botulinum types A and B
Authors: Anellis A , Shattuck E , Morin M , Srisara B , Qvale S , Rowley D B , Ross E W
Published: January 2020

Inoculated, irradiated pork (2,300 cans) and chicken (2,000 cans) pack studies were performed to establish the 12D dose for these foods. Each can was inoculated with a mixture of 10(6) spores of each of 10 strains of Clostridium botulinum (five type A and five type B), or a total of 10(7) spores. The cans received a series of increasing doses of gamma rays (60Co) at -30 +/- 10 degrees C; they were incubated for 6 months at 30 +/- 2 degrees C and examined for swelling, toxicity, and recoverable botulinal cells. The highest rate of swelling for both foods occurred within the first week of incubation, and maximum swelling was observed within 4 to 5 weeks. The minimal experimental sterilizing dose (ESD) based on flat, nontoxic sterile cans was 3.0 less than ESD less than or equal to 3.2 Mrad for pork and 4.0 less than ESD less than or equal to 4.2 Mrad for chicken. An analysis of the partial spoilage data by extreme-value statistics indicated with 90% confidence that the rate of spore death in the two foods was not a normal distribution, but appeared to favor a shifted exponential function. Based on the latter distribution, and assuming one most resistant strain in the mixture of 10 used, the 12D dose computed to 4.37 Mrad, with a shoulder of 0.11 Mrad, for pork and to 4.27 Mrad, with a shoulder of 0.51 Mrad, for chicken. An assumption that there were two or more most resistant strains in the inoculum progressively lowered the 12D dose. There was an apparent antagonism between the irradiated type A and B viable strains in the two foods. Cans with type B cells and toxin predominated over cans with type A cells and toxin, but cans with a mixture of type A and B toxins predominated over cans with a mixture of Type A and B cells. At the highest sublethal doses, only type A cells survived in pork, but in chicken there was a least one type B strain that was at least as resistant as type A strains.
Cultural and physiological characteristics of Clostridium botulinum type G and the susceptibility of certain animals to its toxin
Authors: Ciccarelli A S , Whaley D N , McCroskey L M , Gimenez D F , Dowell V R , Hatheway C L
Published: January 2020

Strain 89 of Clostridium botulinum type G, isolated by Gimenez and Ciccarelli in 1969, was characterized culturally, biochemically, and toxigenically. It was motile, hemolytic asaccharolytic, weakly proteolytic, lipase and lecithinase negative, and it produced acetic, isobutyric, butyric, and isovaleric acids in peptone-yeast extract-glucose broth. No spores were seen in smears from solid or liquid media. Very low levels of toxin were produced in regular broth cultures, but dialysis cultures yielded 30,000 mouse 50% mean lethal doses (LD50 per kg, orally and subcutaneously, respectively; and for guinea pigs, 10,000 to 20,000 and 100 mouse LD50 per kig, intragastrically and intraperitoneally, respectively.
Production of Geosmin in Fermentors and Extraction with an Ion-Exchange Resin
Authors: Gerber Nancy N. , Lechevalier H. A.
Published: January 2020

A method for growing
Streptomyces griseus
LP-16 in fermentors and extracting and purifying geosmin, using an ion-exchange resin, is described.
Production of extracellular enzymes in mutants isolated from trichoderma viride unable to hydrolyze cellulose
Authors: Nevalainen K M , Palva E T
Published: January 2020

Mutant strains not producing cellulases were induced and isolated from the cellulolytic fungus Trichoderma viride. Enrichment of mutants was carried out with the aid of nystatin selection. Mutants were shown to lack the ability to hydrolyze both soluble and crystalline cellulose. Mannanase and xylanase activities were also absent, indicating a common regulation for all these enzymes in T. viride. In some strains aryl-beta-glucosidase activity was also missing. Mutants grew normally, but the amount of proteins secreted into the medium was very low, and in most cases these proteins were qualitatively different from the proteins of the parent strain.
Rapid enumeration of Fecal Coliforms in water by a colorimetric beta-galactosidase assay
Authors: Warren L S , Benoit R E , Jessee J A
Published: January 2020

The colorimetric beta-galactosidase assay is based upon the enzymatic hydrolysis of the substrate o-nitrophenyl-beta-D-galactoside (ONPG) by fecal coliforms. This technique provides an estimate of the fecal coliform concentration within 8 to 20 h. A 100-ml portion of test sample was passed through a 0.45 micrometer membrane filter. This filter was then incubated at 37 degrees C for 1 h in EC medium followed by the addition of filter-sterilized ONPG. The incubation was continued at 44.5 degrees C until a half-maximum absorbance (at 420 nm) was reached. The time between the start of incubation and the half-maximum absorbance was proportional to the concentration of fecal coliforms present. Escherichia coli (K-12) was used to measure the kinetics of substrate hydrolysis and the response time of different cell concentrations. High cell densities produced an immediate response, whereas 1 cell/ml will produce a response in less than 20 h. In field studies in which samples were taken from a range of grossly polluted streams to relatively clean lake water, a linear correlation between ONPG hydrolysis times and fecal coliform most-probable-number values was established. A total of 302 isolates randomly selected from positive ONPG-EC media, which were derived from 11 different habitats, were identified as E. coli (96.69 percent), Enterobacter cloacae (2.32 percent), Klebsiella pneumoniae (0.66 percent), and Citrobacter freundii (0.33 percent).
Immunolatex localization by scanning electron microscopy of intestinal bacteria from cockroaches
Authors: Bracke J W , Markovetz A J
Published: January 2020

An immunolatex reagent was developed from antiserum to Fusobacterium varium, an obligate anaerobe isolated from the colon of the cockroach, Periplaneta americana L. A new technique that enabled the preparation of a highly efficient immunolatex conjugate was used to localize the bacterium with scanning electron microscopy, in situ, in the mixed gut contents.
Comparison of Andersen Eight-Stage and Two-Stage Viable Air Samplers
Authors: Curtis S. E. , Balsbaugh R. K. , Drummond J. G.
Published: January 2020

The two-stage, disposable Andersen air sampler gave lower values for aerial concentration of bacterial colony-forming particles than did the eight-stage Andersen viable air sampler in either a swine house or a classroom.
Vibrio anguillarum and larval mortality in a California coastal shellfish hatchery
Authors: DiSalvo L H , Blecka J , Zebal R
Published: January 2020

Vibrio anguillarum was isolated as a pathogen in the commercial culture of oyster spat at Pigeon Point, Calif. A water-soluble, heat-stable exotoxin extracted from cultures of the vibrio inhibited larval swimming and contributed to larval mortality. Although the vibrio was insensitive to penicillin in standard plate testing, this antibiotic proved useful in preventing mass larval mortalities in the hatchery.
Relative Significance of Exogenous and De Novo Synthesized Fatty Acids in the Formation of Rumen Microbial Lipids In Vitro
Authors: Demeyer D. I. , Henderson C. , Prins R. A.
Published: January 2020

Mixed rumen microorganisms (MRM) or suspensions of rumen Holotrich protozoa obtained from a sheep were incubated anaerobically with [1-
14
C]linoleic acid, [
U
-
14
C]glucose, or [1-
14
C]acetate. With MRM, the total amount of fatty acids present did not change after incubation. An increase in fatty acids esterified into sterolesters (SE) and polar lipids at the expense of free fatty acids was observed. This effect was intensified by the addition of fermentable carbohydrate to the incubations. Radioactivity from [1-
14
C]linoleic acid was incorporated into SE and polar lipids with both MRM and Holotrich protozoa. With MRM the order of incorporation of radioactivity was as follows: SE > phosphatidylethanolamine > phosphatidylcholine. With Holotrich protozoa, the order of incorporation was phosphatidylcholine > phosphatidylethanolamine > SE. With MRM the radioactivity remaining in the free fatty acids and that incorporated into SE was mainly associated with saturated fatty acids, but a considerable part of the radioactivity in the polar lipids was associated with dienoic fatty acids. This effect of hydrogenation prior to incorporation was also noted with Holotrich protozoa but to a much lesser extent. Small amounts of radioactivity from [
U
-
14
C]glucose and [1-
14
C]acetate were incorporated into rumen microbial lipids. With protozoa incubated with [
U
-
14
C]glucose, the major part of incorporated radioactivity was present in the glycerol moiety of the lipids. From the amounts of lipid classes present, their radioactivity, and fatty acid composition, estimates were made of the amounts of higher fatty acids directly incorporated into microbial lipids and the amounts synthesized de novo from glucose or acetate. It is concluded that the amounts directly incorporated may be greater than the amounts synthesized de novo.
Breaks induced in the deoxyribonucleic acid of aerosolized Escherichia coli by ozonized cyclohexene
Authors: De Mik G , De Groot I
Published: January 2020

The inactivation of aerosolized Escherichia coli by ozone, cyclohexene, and ozonized cyclohexene was studied. The parameters for damage were loss of reproduction and introduction of breaks in the deoxyribonucleic acid (DNA). Aerosolization of E. coli in clean air at 80 percent relative humidity or in air containing either ozone or cyclohexene hardly affected survival; however, some breaks per DNA molecule were induced, as shown by sucrose gradient sedimentation of the DNA. Aerosolization of E. coli in air containing ozonized cyclohexene at 80 percent relative humidity decreased the survival by a factor of 10(3) or more after 1 h of exposure and induced many breaks in the DNA.
Regional variations of cutaneous propionibacteria
Authors: McGinley K J , Webster G F , Leyden J J
Published: January 2020

Propionibacterium acnes, P. avidum, and P. granulosum were quantitatively measured in 50 young adults. The scalp, forehead, external auditory canal, alae nasi, anterior nares, groin, rectum, and antecubital and popliteal fossa were sampled. These represent various cutaneous microenvironments, differing in moisture, density of sweat, sebaceous glands, and extent of anaerobiosis. These studies show that the propionibacteria are ubiquitous on the skin, with P. acnes predominant in both prevalence and population, especially in areas rich in sebum. P. granulosum recovery paralled that of P. acnes, but the density was significantly lower. P. avidum was found mainly in moist areas and the retum, suggesting an intestinal reservoir.
Effect of Chlorine Substitution on the Biodegradability of Polychlorinated Biphenyls
Authors: Furukawa Kensuke , Tonomura Kenzo , Kamibayashi Akira
Published: January 2020

Thirty-one isomers of polychlorinated biphenyl (PCB) were examined for biodegradability by two species of
Alcaligenes
and
Acinetobacter.
The following relationships between chlorine substitution and biodegradability of PCBs were observed. (i) Degradation decreased as chlorine substitution increased. PCB isomers containing more than four chlorines were less susceptible to degradation. (ii) PCBs containing two chlorines on either the
ortho
position of a single ring (i.e., 2,6-) or on both rings (i.e., 2,2′-) showed very poor degradability. (iii) PCBs containing all chlorine atoms on only a single ring were generally degraded faster than when the same number of chlorines were substituted on both rings. (iv) Preferential ring fission of the molecules occurred with nonchlorinated or lesser chlorinated rings. (v) The formation and accumulation of a yellow intermediate was always observed in 4′-chloro-substituted PCBs. (vi) Significant differences between the two organisms with respect to degradability were not observed except for 2,4,6-trichlorobiphenyl.
Membrane filter procedure for enumeration of Candida albicans in natural waters
Authors: Buck J D , Bubucis P M
Published: January 2020

A membrane filter procedure is described for the enumeration of Candida albicans in natural waters. Several hundred milliliters of sample can be examined by filtration through 1.2-micrometer membranes. Selectivity is achieved by the use of a defined (yeast-nitrogen base plus maltos-) agar medium inclusion of the antimicrobial agents chloramphenicol and cycloheximide, and incubation at 37 degrees C. C. albicans colonies are differentiated primarily through color by use of a bismuth salt indicator system. Average recovery of various strains of C. albicans stressed in seawater at 4 degrees C was 82%, compared with those of spread plate controls on a noninhibitory medium. With river water and raw sewage, 90% of typical C. albicans colonies were confirmed as such in a simplified germ tube test. Atypical colonies verified as C. albicans were infrequent (3%). C. tropicalis and Torulopsis candida were the most common false-positive colonies.
Metabolism of Di- and Mono-
n
-Butyl Phthalate by Soil Bacteria
Authors: Engelhardt G. , Walln�fer P. R.
Published: January 2020

Di-
n
-butyl phthalate and other dialkyl phthalates are used as carbon sources by three
Nocardia
sp. isolates; mono-
n
-butyl phthalate is used as a carbon source by an
Arthrobacter
sp. isolate and a
Pseudomonas
sp. isolate. The compounds were metabolized in these organisms by hydrolysis to the corresponding monoesters and free phthalic acid. Phthalic acid was then metabolized via protocatechuic acid by 3,4-dioxygenative ring cleavage.
Enhanced virus replication in mammalian cells exposed to commercial emulsifiers
Authors: Rozee K R , Lee S H , Crocker J F , Safe S H
Published: January 2020

Mammalian cell cultures were used to show that a variety of commercial emulsifiers are capable of enhancing the sensitivity of these cells to infection with several viruses. Some emulsifiers were not active as enhancers, and those viruses that responded to the enhancing emulsifiers were single-stranded ribonucldic acid viruses. The double-stranded viruses that were tested were nonresponders.
Capacity for Denitrification and Reduction of Nitrate to Ammonia in a Coastal Marine Sediment
Authors: S�rensen Jan
Published: January 2020

The capacity for dissimilatory reduction of NO
3
−
to N
2
(N
2
O) and NH
4
+
was measured in
15
NO
3
−
-amended marine sediment. Incubation with acetylene (7 � 10
−3
atmospheres [normal]) caused accumulation of N
2
O in the sediment. The rate of N
2
O production equaled the rate of N
2
production in samples without acetylene. Complete inhibition of the reduction of N
2
O to N
2
suggests that the “acetylene blockage technique” is applicable to assays for denitrification in marine sediments. The capacity for reduction of NO
3
−
by denitrification decreased rapidly with depth in the sediment, whereas the capacity for reduction of NO
3
−
to NH
4
+
was significant also in deeper layers. The data suggested that the latter process may be equally as significant as denitrification in the turnover of NO
3
−
in marine sediments.
Microbial Transformation of Polycyclic Aromatic Hydrocarbons in Pristine and Petroleum-Contaminated Sediments
Authors: Herbes S. E. , Schwall L. R.
Published: January 2020

To determine rates of microbial transformation of polycyclic aromatic hydrocarbons (PAH) in freshwater sediments,
14
C-labeled PAH were incubated with samples from both pristine and petroleum-contaminated streams. Evolved
14
CO
2
was trapped in KOH, unaltered PAH and polar metabolic intermediate fractions were quantitated after sediment extraction and column chromatography, and bound cellular
14
C was measured in sediment residues. Large fractions of
14
C were incorporated into microbial cellular material; therefore, measurement of rates of
14
CO
2
evolution alone would seriously underestimate transformation rates of [
14
C]naphthalene and [
14
C]anthracene. PAH compound turnover times in petroleum-contaminated sediment increased from 7.1 h for naphthalene to 400 h for anthracene, 10,000 h for benz(a)anthracene, and more than 30,000 h for benz(a)pyrene. Turnover times in uncontaminated stream sediment were 10 to 400 times greater than in contaminated samples, while absolute rates of PAH transformation (micrograms of PAH per gram of sediment per hour) were 3,000 to 125,000 times greater in contaminated sediment. The data indicate that four- and five-ring PAH compounds, several of which are carcinogenic, may persist even in sediments that have received chronic PAH inputs and that support microbial populations capable of transforming two- and three-ring PAH compounds.
Effects of Polychlorinated Biphenyls on Macromolecular Synthesis by a Heterotrophic Marine Bacterium
Authors: Blakemore Richard P.
Published: January 2020

Growth rates and final cell yields of a polychlorinated biphenyl (PCB)-sensitive pseudomonad isolated from the open ocean were reduced in a dose-dependent manner by 10 to 100 μg of Aroclor 1254 per liter, a commercial mixture of PCB isomers added to its culture medium. Effects on growth rates were detected within 1 h (approximately one doubling time) of treatment. By 4 h posttreatment, the amounts of deoxyribonucleic acid and ribonucleic acid per cell in exponentially growing populations treated with sublethal doses of Aroclor were detectably lower than in appropriate controls. Corresponding cell protein values were slightly higher than in controls. Selective degradation of cell proteins or nucleic acids was not detected in cells whose growth was totally suppressed for 4 h by PCBs. Cells whose growth rate was inhibited 20 to 50% by Aroclor synthesized protein at normal rates for periods in excess of 5 h from the time the chlorinated hydrocarbons were added. In contrast, rates per cell of adenine uptake and adenine incorporation into deoxyribonucleic acid and total nucleic acids by the cells treated with PCBs were significantly lower than in control cells. Intracellular adenine pools of cells whose growth was inhibited to 20% of the control rate by PCBs were 30% smaller and appeared to require a longer interval to equilibrate than those of untreated cells. This may indicate impaired transport and/or efflux of this nucleic acid precursor through the membrane of affected cells. Inhibition of nucleic acid synthesis in this sensitive bacterium by PCBs could explain the observed inhibitory effects of the chlorinated hydrocarbons on its growth.
Methane, Carbon Dioxide, and Hydrogen Sulfide Production from the Terminal Methiol Group of Methionine by Anaerobic Lake Sediments
Authors: Zinder S. H. , Brock T. D.
Published: January 2020

A significant portion of the sulfide in lake sediments may be derived from sulfur-containing amino acids. Methionine degradation in Lake Mendota (Wisconsin) sediments was studied with gas chromatographic and radiotracer techniques. Temperature optimum and inhibitor studies showed that this process was biological. Methane thiol and dimethyl sulfide were produced in sediments when 1-μmol/ml unlabeled methionine was added. When chloroform (an inhibitor of one-carbon metabolism) was added to the sediments, methane thiol, carbon disulfide, and
n
-propane thiol were produced, even when no methionine was added. When
35
S-labeled methionine was added to the sediments in tracer quantities (1.75 nmol/ml), labeled hydrogen sulfide was produced, and a roughly equal amount of label was incorporated into insoluble material. Methane and carbon dioxide were produced from [
methyl
-
14
C]methionine. Evidence is given favoring methane thiol as an intermediate in the formation of methane, carbon dioxide, and hydrogen sulfide from the terminal methiol group of methionine. Methionine may be an important source of sulfide in lake sediments.
Cometabolism of DDT analogs by a Pseudomonas sp
Authors: Francis A J , Spanggord R J , Ouchi G I , Bohonos N
Published: January 2020

A Pseudomonas sp. capable of growth on several nonchlorinated and mono-p-chloro-substituted analogs of DDT as a sole carbon source degraded bis(p-chlorophenyl)methane and 1,1-bis(p-chlorophenyl)ethane only in the presence of diphenylethane. The products p-chlorophenylacetic acid and 2-(p-chlorophenyl)-propionic acid were not further metabolized by the bacterium. Other chlorinated analogs of DDT were found to be recalcitrant to cometabolic degradation with diphenylethane.
Rapid Determination of Bacteriological Water Quality by Using
Limulus
Lysate
Authors: Evans T. M. , Schillinger J. E. , Stuart D. G.
Published: January 2020

The
Limulus
lysate assay was used to measure the endotoxin content in stream water and was found to reflect the degree of bacterial contamination as measured by coliform, enteric, gram-negative, and heterotrophic bacteria. The firm-clot method was found to be a less sensitive and reproducible technique for the detection of endotoxin than was the spectrophotometric modification of the
Limulus
lysate assay. Bound endotoxin, as determined by the spectrophotometric modification of the
Limulus
lysate assay, was found to be a better measure of the endotoxin associated with bacterial cells than was total endotoxin.
Significance of low-temperature growth associated with the fecal coliform response, indole production, and pectin liquefaction in Klebsiella
Authors: Naemura L G , Seidler R J
Published: January 2020

In the genus Klebsiella, the growth respnse in nutient broth at 10 degrees C correlates inversely with the operational definition of a fecal coliform and not merely with the ability to grow at 44.5 degrees C. Of the fecal coliform-positive Klebsiella, 97% did not grow at 10 degrees C after 72 h of incubation. Conversely, 97% of the fecal coliform-negative isolates grew at 10 degrees C. The amount of growth at 10 degrees C varied among the fecal coliform-negative isolates and was found to correlate with indole production and pectin liquefaction. Low-temperature growth associated with specific biochemical tests can be used to differentiate several groups in the genus Klebsiella. Three main groups were discerned. Group I consists of indole-negative, pectin-nonliquefying, fecal coliform-positive isolates that do not grow at 10 degrees C. Group II isolates are differentiated from group I by a fecal-coliform-negative response and growth at 10 degrees C. Group III are indole-positive, pectin-liquefying, fecal coliform-negative isolates that grow at 10 degrees C. In our culture collection, isolates of group I are most frequently of human/animal clinical origins, whereas isolates of groups II and III are predominantly derived from the environment.
Distribution of
Methylomonas methanica
and
Methylosinus trichosporium
in Cleveland Harbor as Determined by an Indirect Fluorescent Antibody-Membrane Filter Technique
Authors: Reed William M. , Dugan Patrick R.
Published: January 2020

An indirect fluorescent antibody-membrane filter staining technique, which permitted the autecological study of
Methylomonas methanica
and
Methylosinus trichosporium
, was developed. This technique was used to assay the numbers of these two organisms in Cleveland Harbor. The concentrations of
M. methanica
and
M. trichosporium
were found to be inversely proportional to the sampling depth, with the highest cell counts observed in the sediments.
M. methanica
was observed at every sampling station, whereas
M. trichosporium
was found at only two of the stations.
Production of Venezuelan equine encephalitis virus in cells grown on artificial capillaries
Authors: Johnson A D , Eddy G A , Gangemi J D , Ramsburg H H , Metzger J F
Published: January 2020

Primary cell cultures, a continuous cell line, and a diploid cell line were grown on an artificial capillary system. The cells were subsequently infected with Venezuelan equine encephalitis virus, and viral replication was studied. Extracellular fluids harvested from this system contained high titers of virus and were relatively free of cell debris.
Observations on toxin and hemagglutinin produced by Clostridium botulinum type C
Authors: Oguma K , Nakane A , Iida H
Published: January 2020

In the culture fluid of a hemagglutinin-positive strain of Clostridium botulinum type C, two toxins of different molecular size, hemagglutinin positive and negative, were separated by sucrose density gradient centrifugation.
Effect of Lactose Concentration on the Efficiency of Plating of Bacteriophages on
Streptococcus cremoris
Authors: Terzaghi Eric A. , Terzaghi Betty E.
Published: January 2020

The efficiency of plating of phages derived by ultraviolet induction of, or by lytic growth on, certain strains of
Streptococcus cremoris
was found to vary by as much as 10
5
depending on the lactose concentration of the medium in which the indicator bacteria were grown and the length of time the stationary-phase indicator cultures were aged. This effect was noted only when the culture was used as an indicator for phages that had previously grown on an apparently unrelated strain of bacteria. Conditions of culturing and aging had no detectable effect upon the ability of a strain to serve as an indicator for phage that had previously been cultured on the same strain. These observations suggest the presence of some kind of physiologically labile restriction system in strains of
S. cremoris.
The implications of this finding for increasing the sensitivity of the host range test in determining phage susceptibility, whether from induced lysates, whey, or lytic phage stocks, are discussed. It is recommended that, for all such testing, the concentration of lactose in buffered media be increased to such levels as required to obtain a final pH similar to that of a freshly coagulated milk culture, namely, below pH 5.0.
Maintenance of a certain rumen protozoal population in a continuous in vitro fermentation system
Authors: Nakamura F , Kurihara Y
Published: January 2020

A continuous culture system suitable for maintaining certain rumen protozoa was developed by modifying the procedure of Walter and Pilgrim (R.A. Weller and A.F. Pilgrim, Br. J. Nutr. 32:341-351, 1974) to include a dialyzing system. The concentration of ciliate protozoa, the pH value, and concentrations of volatile fatty acid and ammonia-N could be maintained within normal rumen limits for more than 15 days by appropriate choice of mechanical agitation and of the amount of substrate and physical form of the substrate bags. The average concentration of protozoa in the free fluid around the substrate was about 10% that in the fluid squeezed from solid digesta residues. More than 10(6) protozoa per ml was present in the fresh substrates only 2 h after supplying the substrate. These facts suggest that sequestration of the protozoa among particulate digesta is an important factor in maintaining the concentration of protozoa.
Reduction of azo dyes by intestinal anaerobes
Authors: Chung K T , Fulk G E , Egan M
Published: January 2020

Reduction of seven azo dyes (amaranth, Ponceau SX, Allura Red, Sunset Yellow, tartrazine, Orange II, and methyl orange) was carried out by cell suspensions of predominant intestinal anaerobes. It was optimal at pH 7.4 in 0.4 M phosphate buffer and inhibited by glucose. Flavin mononucleotide caused a marked enhancement of azo reduction by Bacteroides thetaiotaomicron. Other electron carriers, e.g., methyl viologen, benzyl viologen, phenosafranin, neutral red, crystal violet, flavin adenine dinucleotide, menadione, and Janus Green B can replace flavin mononucleotide. These data suggest that an extracellular shuttle is required for azo reduction.
Production of luteoskyrin and isolation of a new metabolite, pibasterol, from Penicillium islandicum Sopp
Authors: Ghosh A C , Manmade A , Kobbe B , Townsend J M , Demain A L
Published: January 2020

Production of luteoskyrin, a hepatotoxin synthesized by Penicillium islandicum Sopp., was studied with various fermentation methods. Best results were obtained in static fermentations on glutinous rice at 30 degrees C. The isolated yield of pure luteoskyrin was approximately 400 mg per kg of rice. Also produced were skyrin, islandicin, iridoskyrin, rubroskyrin, chrysophanol, mannitol, and erythritol. A new metabolite, which we call pibasterol, was also isolated.
Simple procedure for disruption of fungal spores
Authors: Van Etten J L , Freer S N
Published: January 2020

A simple, inexpensive method for disrupting dormant fungal spores is described.
Changes in proportions of acetate and carbon dioxide used as methane precursors during the anaerobic digestion of bovine waste
Authors: Mountfort D O , Asher R A
Published: January 2020

In an anaerobic digestor which was fed daily with bovine waste, during the early stages after feeding (4 to 7 h) acetate (via the methyl group) accounted for almost 90% of the methane produced. As time after feeding increased, acetate declined as a precursor so that in the 12- to 14-h and 21- to 23-h periods, after feeding the methyl group accounted for 80 and 73% of the methane produced, respectively. Measurements of methane production from CO2 reduction showed that in the 2- to 12-h period after feeding, CO2 accounted for 14% of the methane produced, whereas in the 12- to 24-h period it accounted for 27-5%. These results show that the percentages of methane accounted for by acetate and CO2 vary with time after feeding the digestor.
Lack of mutagenicity to Salmonella typhimurium of some Fusarium mycotoxins
Authors: Wehner F C , Marasas W F , Thiel P G
Published: January 2020

The mutagenicity of eight Fusarium toxins (mono-, di-, and triacetoxyscirpenol, T-2 toxin, deoxynivalenol, 3-acetyl-deoxynivalenol, zearalenone, and moniliformin) and of two positive controls (aflatoxin B1 and sterigmatocystin) to histidine-requiring strains TA 98, 100, 1535, and 1537 of Salmonella typhimurium was tested both with and without metabolic activation. Both aflatoxin B1 and sterigmatocystin, but none of the eight Fusarium toxins, were mutagenic to S. typhimurium. The lack of mutagenic activity of T-2 toxin and diacetoxyscirpenol supports the negative results that have been obtained with in vivo carcinogenicity tests. The negative mutagenicity of the four other 12,13-epoxytrichothecenes tested, and of zearalenone and moniliformin, could not be correlated with in vivo tests because published accounts of their chronic toxicity were not available.
Method for Sampling Beef Carcasses
Authors: Davidson Charles M. , Taylor Mary , Zellerman Gabor G.
Published: January 2020

An instrument resembling a surgical dermatome, for microbiological sampling of beef carcasses, is described.
Inhibition of light-induced pH increase and O2 evolution of marine microalgae by water-soluble components of crude and refined oils
Authors: Armstrong J E , Calder J A
Published: January 2020

Light-induced alkalinization of the extracellular medium was found to be a common feature of the primary photosynthetic process of several marine microalgae. The light-induce PH increase of suspensions of whole cells was immediately and severely inhibited by a single dose of water-soluble components from crude and fuel oils. Differential effects on the rates of microalgal photosynthetic O2 evolution and cell suspension pH increase suggest different toxicity mechanisms of the water-soluble components of no. 2 fuel oil as compared with Southern Louisiana and Jay Crude oils. These short-term studies on the nature of sublethal petroleum toxicity to microalgae indicate that the primary effect may be through direct action on the energy-yielding electron transport systems.
Kinetics of biodegradation of p-nitrobenzoate and inhibition by benzoate in a pseudomonad
Authors: Haller H D , Finn R K
Published: January 2020

The degradation of p-nitrobenzoate (p-NBA) by domestic sewage was inhibited by benzoate, and a model for this behavior was found in a soil isolate. The isolate, a pseudomonad, utilized p-NBA and benzoate by separate adaptive enzyme pathways. In oxygen uptake experiments, the degradation of p-NBA was competitively inhibited by benzoate, but the degradation of benzoate was not affected by the presence of p-NBA. 4-Nitrocatechol was not implicated in the inhibition. p-Hydroxybenzoate, which is the p-NBA degradation pathway, also had a decreased rate od degradation when benzoate was present. The growth rate of the isolate on the aromatic substrates and on glucose autoclaved in the medium was 0.3 h-1. When glucose was autoclaved separately, the growth rate was less, about 0.2 h-1. The apparent Km in oxygen uptake experiments was 25 micrometer for p-NBA and benzoate and 5 micrometer for p-hydroxybenzoate.
Cultural and Environmental Factors Affecting the Longevity of
Escherichia coli
in Histosols
Authors: Tate Robert L.
Published: January 2020

The survival of
Escherichia coli
in organic soils (Histosols) was examined. The death rate of this organism in Pahokee muck was less than that observed in Pompano fine sand. The number of viable
E. coli
cells found in the muck was approximately threefold greater than that found in the sand following 8 days of incubation. The initial population of the coliform affected the death rate. The rate of loss of viability varied 100-fold when the population size decreased from 2.5 × 10
7
to 3.4 × 10
4
. Other factors affecting the viability of
E. coli
in muck were aerobic versus anaerobic growth of the organism and moist versus flooded conditions in the soil. The greatest survival of the coliform was noted with anaerobically grown cells amended to flooded soil. That the observed decrease in
E. coli
viability in soil was the result of biotic factors was demonstrated with amendment of sterile soil with
E. coli.
When 1.1 × 10
5
bacteria per g of soil were added to sterile muck, a population of 3.0 × 10
7
organisms per g of soil developed over a 10-day period. The role of the protozoa in eradication of the coliform from the muck was indicated by a sixfold increase in the protozoan population in natural soil amended with
E. coli.
Higher organic matter content in a Histosol compared with a mineral soil resulted in an increased survival of the fecal coliforms. Biotic factors are instrumental in the decline in coliform populations, but the potential for growth of the coliform in the organic soil could extend the survival of the organism.
Heterotrophic bacteria present in hindguts of wood-eating termites [Reticulitermes flavipes (Kollar)]
Authors: Schultz J E , Breznak J A
Published: January 2020

Strict anaerobic culture techniques were used to quantitate heterotrophic bacteria present in hindguts of Reticulitermes flavipes. The grand mean number of viable cells per hindgut was 0.4 X 10(5) (first-instar larvae), 1.3 X 10(5) (third-instar larvae), 3.5 X 10(5) (workers), and 1.5 X 10(5) (soldiers). Of a total of 344 isolates, 66.3% were streptococci that were always obtained regardless of the origin of termites, their developmental stage or caste, or their length of captivity. Most of the remaining isolates were strains of Bacteroides and Enterobacteriaceae. A small percentage were strains of Lactobacillus, Fusobacterium, and unidentified anaerobic gram-positive rods. Recovery of bacteria from worker hindguts was 13.0% of the direct microscopic count. Isolations performed aerobically failed to reveal strict aerobes. Attempts to isolate cellulolytic bacteria were uniformly unsuccessful. Of 145 streptococcal strains isolated from freshly collected termites, almost all were Streptococcus lactis and S. cremoris. Enterobacteriaceae isolates from the same termite specimens were indole-positive Citrobacter, citrate-negative Citrobacter, and Enterobacter cloacae. The possibility of in situ interspecies lactate transfer, between lactate producers (e.g., streptococci) and lactate fermenters (Bacteroides), is discussed.
Microbial transformation of 14C-labeled 2,4,6-trinitrotoluene in an activated-sludge system
Authors: Carpenter D F , McCormick N G , Cornell J H , Kaplan A M
Published: January 2020

The fate of 14C-labeled 2,4,6-trinitrotoluene (TNT) in an activated-sludge system was investigated. No [14C]TNT could be detected in the contents of an aerated reactor after 3 to 5 days of incubation. No significant 14CO2 was formed, and the radioactivity was about equally divided between the floc and the supernatant. The radioactive carbon present in the microflora was mainly associated with the lipid and protein components, but the characteristic constituents of these compounds (e.g., fatty acids and amino acids) were not radioactive. The major part of the 14C present in the lipid and protein fractions was found in precipitates that formed in both fractions. The solubility properties and infrared spectra of these precipitates suggested that they are macromolecular structures of the polyamide type formed by the reaction of TNT biotransformation products with lipids, fatty acids, and protein constituents of the microbial flora. This hypothesis is further supported by the correspondence of the infrared spectrum of the lipid precipitate with that of a model compound synthesized from TNT transformation products and lipid precursors. The resistance of these macromolecules to further biodegradation was paralleled by the reported resistance to microbial attack of polyamides containing similar linkages.
Pathway of degradation of nitrilotriacetate by a Pseudomonas species
Authors: Firestone M K , Tiedje J M
Published: January 2020

The pathway of degradation of nitrilotriacetate (NTA) was determined by using cell-free extracts and a 35-fold purification of NTA monooxygenase. The first step in the breakdown was an oxidative cleavage of the tertiary amine by the monooxygenase to form the aldo acid, glyoxylate, and the secondary amine, iminodiacetate (IDA). NTA N-oxide acted as a substrate analog for induction of the monooxygenase and was slowly metabolized by the enzyme, but was not an intermediate in the pathway. No intermediate before IDA was found, but an unstable alpha-hydroxy-NTA intermediate was postulated. IDA did undergo cleavage in the presence of the purified monooxygenase to give glyoxylate and glycine, but was not metabolized in cell-free extracts. Glyoxylate was further metabolized by cell-free extracts to yield CO2 and glycerate or glycine, products also found from NTA metabolism. Of the three bacterial isolates in which the NTA pathway has been studied, two strains, one isolated from a British soil and ours from a Michigan soil, appear to be almost identical.