bluuebunny/crossref_metadata_2025 huggingface dataset:
Plate diffusion assay as a rapid method for dosimetry of mutagens
Authors: Awerbuch T E , Stark A A
Published: January 2020

This paper presents a method for determining mutagenic concentrations of chemicals by using an agar diffusion assay. The method is based on the linear relationship between the amount of chemical placed at the center of the dish and the radius of the mutagenic zone. A brief theoretical discussion and experimental data confirming this relationship are given. Alkylating agents and mycotoxins were used to test the system. This method can be used to follow up decreased mutagenic potencies of solutions of unstable mutagens and to follow the production of mutagenic substances throughout fermentation.
Influence of pork consumption on human infection with Mycobacterium avian-intracellulare
Authors: Brown J , Tollison J W
Published: January 2020

The hypothesis that eating pork from animals infected with organisms of the Mycobacterium avium-intracellular complex is a significant cause of human mycobacteriosis was examined by skin testing students with purified protein derivative from M. intracellulare to determine their sensitivity to M. avium-intracellulare. No significant differences in sensitivity could be demonstrated between those individuals who had never eaten pork and those who ate pork routinely. It was concluded that sensitivity to purified protein derivative from M. intracellulare in this population did not involve eating pork.
Localization of Active Microorganisms in Cheese by Autoradiography
Authors: Reyrolle Jean , Letellier François
Published: January 2020

By using an autoradiographic technique, one can follow, during ripening of a cheese, the distribution, size, and metabolic activity of microcolonies. Fragments of cheese were labeled with [
3
H]leucine, fixed, and mounted in epoxy resin. After exposure and development, sections were examined by optical microscopy. In Camembert cheese, bacterial microcolonies synthesized protein rapidly during the beginning of the ripening process. At the end of the ripening process, active bacterial clusters were scarcer and of two types: (i) large microcolonies with reduced labeling, and (ii) microcolonies having the same size as those observed at the beginning of the ripening process, but with slight or no labeling.
Characterization of
Azospirillum
Isolated from Nitrogen-Fixing Roots of Harvested Sorghum Plants
Authors: Wong Peter P. , Stenberg Nancy E.
Published: January 2020

Root segments of harvested sorghum plants had acetylene reduction activity ranging from 11 to 61 nmol of ethylene formed per h per g (dry weight). Five strains of
Azospirillum brasilense
sp. nov. were isolated from root segments.
Enzymatic formation of the bisfuran structure in aflatoxin biosynthesis
Authors: Wan N C , Hsieh D P
Published: January 2020

A relatively stable enzyme system that converts versiconal hemiacetal acetate to versicolorin A was isolated from the soluble fraction of the homogenized cells of Aspergillus parasiticus ATCC 15517. The cell-free preparation did not require oxygen or oxidized nicotinamide adenine dinucleotide phosphate for activity, nor did it require dithiothreitol, polyclar (polyvinyl pyrrolidone), or glycerol for stabilization of activity. It was susceptible to inhibition by dichlorvos and cysteine. Isotope tracer studies revealed involvement of several intermediates in the conversion of versiconal hemiacetal acetate to versicolorin A. These findings confirm the biogenetic relationship of versiconal hemiacetal acetate and versicolorin A, and they confirm that the bisfuran ring structure in aflatoxins and related fungal metabolites is derived from the hemiacetal structure of versiconal hemiacetal acetate.
Enumeration of potentially pathogenic bacteria from sewage sludges
Authors: Dudley D J , Guentzel M N , Ibarra M J , Moore B E , Sagik B P
Published: January 2020

To ascertain the health risks that may be posed by the land application of sewage sludges, a scheme was devised to determine the types and numbers of pathogenic and potentially pathogenic bacteria present in sludges. A processing treatment was adapted to sludge to give a homogenate which yielded the greatest numbers of viable bacteria. Conventional methods were successful in enumerating Klebsiella, Staphylococcus, gram-negative enteric bacteria, and commonly used indicator organisms. Modifications of conventional methods improved the enumeration of Salmonella, Mycobacterium sp., fluorescent Pseudomonas sp., and Clostridium perfringens. However, Shigella methodology yielded only one isolate. Utilizing the proposed scheme, the population densities of these organisms were estimated in three domestic wastewater sludges. In light of these results, the potential impact of land application of sewage sludges is discussed.
Evaluation of the overland runoff mode of land wastewater treatment for virus removal
Authors: Schaub S A , Kenyon K F , Bledsoe B , Thomas R E
Published: January 2020

The removal of enteric and tracer viruses by the overland runoff mode of domestic wastewater treatment was evaluated. Raw and primary and secondary treated wastewaters were sprayed onto grass-covered, 36-m soil plots of fine, sandy loam overlying an impermeable clay subsoil. Tracer bacteriophage f2 was seeded into the applied wastewaters, which were subsequently sampled at several points along the length of the plots. Assay of effluent samples revealed modest tracer virus removals of 30 to 60%. Data from timed experiments indicated that advancement of tracer virus to the bottom of the slopes proceeded at the same rate as wastewater, reaching the plot effluents within 50 to 90 min after application. Indigenous enteric virus levels were reduced by approximately 68 to 85% during migration down the treatment slopes. Soil sampling revealed that, although some f2 virus was found associated with the wastewater-saturated topsoil, little penetration of virus into the soil profile occurred. Laboratory soil adsorption studies revealed that poliovirus I was adsorbed much more readily than f2 virus. Comparison of virus removal characteristics during overland runoff with chemical removal characteristics of wastewater did not reveal any obvious correlations that could be used to predict virus removal.
Improved method and test strategy for recovery of enteric viruses from shellfish
Authors: Metcalf T G , Moulton E , Eckerson D
Published: January 2020

An improved recovery method and testing strategy were devised for recovery of low numbers of enteric viruses from each of three commercially important shellfish species. Effective recovery of virus depended as much upon details of the test strategy adopted for use of the improved method with each species as on the method itself. The most important test details involved sample composition, pool size, and method of use of cell cultures. Recovery sensitivity measured permitted detection of 25 to 3 plaque-forming units of enteroviruses and 100 to 27 plaque-forming units of reovirus through their recovery in cell culture, with effectivenesses averaging 64 and 46%, respectively. Test samples prepared by the improved recovery method were virtually cytotoxicity free. Optimal recovery of virus on 45-cm2 cell culture monolayers was obtained with 1-ml inocula adsorbed for 2 h. The most effective recovery of virus from shellfish samples was made by a sequential adsorption procedure which allowed equal exposure of an entire sample to each of two or more cell cultures. Removal of nonviral contaminants from test samples by antibiotic treatment was preferable to the use of ether or membrane filtration procedures.
Method for the lysis of Gram-positive, asporogenous bacteria with lysozyme
Authors: Chassy B M , Giuffrida A
Published: January 2020

A method developed for the lysis of oral streptococci that employed the action of lysozyme suspended in dilute tris(hydroxymethyl)aminomethane-hydrochloride buffer containing polyethylene glycol has been adapted for use with lactobacilli, actinomycetes, propionibacteria, and pediococci. Most of the cellular deoxyribonucleic acid was liberated from many strains of bacteria usually thought to be lysozyme resistant. The major observations were as follows: (i) supplementation of the growth medium with L-threonine, L-lysine, or both frequently produced cells that were more susceptible to lysis by lysozyme; (ii) glucose-containing media produced cells that were more easily lysed than those from cultures grown on other substrates; (iii) polyethylene glycol not only served as an osmotic stabilizer, it also enhanced the extent of lysis; and (iv) dilute tris(hydroxymethyl)aminomethane buffer was superior to the buffer systems most commonly employed in published muramidase-based lysis techniques. Stationary-phase cells of Lactobacillus casei and Streptococcus mutans were more easily lysed than those isolated from log-phase cultures. The method as detailed in this report should be generally applicable for the lysis of gram-positive, asporogenous bacteria.
The janthitrems: fluorescent tremorgenic toxins produced by Penicillium janthinellum isolates from ryegrass pastures
Authors: Gallagher R T , Latch G C , Keogh R G
Published: January 2020

New tremorgenic mycotoxins named janthitrem A, B, and C (molecular weights 601, 585, and 569, respectively) were produced by more than half of 21 Penicillium janthinellum isolates obtained from ryegrass pastures involved in ryegrass staggers outbreaks in sheep.
Microbial lipolysis at low temperatures
Authors: Andersson R E
Published: January 2020

It was found that lipase production during the growth of Pseudomonas fluorescens was not a function of the total number of bacteria. The optimal temperatures for bacterial growth and lipase production were determined as 20 and 8 degrees C, respectively. The lipolytic activity was studied in emulsions of olive oil at temperatures ranging from +8 to -30 degrees C. After an initially rapid lipolysis, the reactions retarded at different levels depending on storage temperature. Transference to a higher temperature resulted in a resumed lipolysis. Also, at low temperatures, lipolysis was studied as a function of water activity and was found to occur in dehydrated substrates.
Isolation of the Mycobacterium avium-M. intracellulare-M. scrofulaceum complex from tank water in Queensland, Australia
Authors: Tuffley R E , Holbeche J D
Published: January 2020

Disease-associated serotypes of Mycobacterium intracellulare and M. avium have been isolated from 32 of 141 rainwater tanks situated in the basin of the Fitzroy River and its tributaries in central Queensland, 7 of 32 tanks situated in the hinterland of the coastal city of Rockhampton, and 2 of 32 tanks sampled repetitively in the southeastern Queensland city of Toowoomba. M. gordonae was also isolated from 23 of the river basin tanks, from 9 in the Rockhampton hinterland, and from 5 in the city of Toowoomba. One half of these isolates came from tanks which also yielded M. intracellulare. Mycobacteria of the M. terrae-M. triviale-M. nonchromogenicum complex were found in 7 tanks, usually in conjunction with M. intracellulare. The humans who consume the contaminated tank water are free of symptoms but have not been medically examined. It is suggested that mycobacteria adhering to dust particles disturbed by mechanical cultivation may be the source of contamination.
Large-scale purification of Japanese encephalitis virus from infected mouse brain for preparation of vaccine
Authors: Aizawa C , Hasegawa S , Chih-Yuan C , Yoshioka I
Published: January 2020

Large volumes of Japanese encephalitis (JE) virus propagated in mouse brain can be easily purified by polyethylene glycol 6,000. By using the polyethylene glycol precipitation method, mouse hemoglobin was almost all separated from the viral suspension, and consequently the total amount of nonviral protein in the viral suspension decreased. The recovery of infectivity was about 100%. The removal of residual polyethylene glycol in the viral suspension was possible without difficulty by means of ethanol precipitation. This method is recommended as an initial step in large-scale purification of Japanese encephalitis virus propagated in mouse brain because it is simple, rapid, and inexpensive.
Critical Reactions in Fluorobenzoic Acid Degradation by
Pseudomonas
sp. B13
Authors: Schreiber A. , Hellwig M. , Dorn E. , Reineke W. , Knackmuss H.-J.
Published: January 2020

3-Chlorobenzoate-grown cells of
Pseudomonas
sp. B13 readily cometabolized monofluorobenzoates. A catabolic pathway for the isomeric fluorobenzoates is proposed on the basis of key metabolites isolated. Only 4-fluorobenzoate was utilized and totally degraded after a short period of adaptation. The isoenzymes for total degradation of chlorocatechols, being found during growth with 3-chlorobenzoate or 4-chlorophenol, were not induced in the presence of fluorobenzoates. Correspondingly, only the ordinary enzymes of the benzoate pathway were detected in 4-fluorobenzoate-grown cells. Ring cleavage of 3-fluorocatechol was recognized as a critical step in 3-fluorobenzoate degradation. 2-Fluoro-
cis,cis
-muconic acid was identified as a dead-end metabolite from 2- and 3-fluorobenzoate catabolism. During 2-fluorobenzoate cometabolism, fluoride is eliminated by the initial dioxygenation.
Adaptation of
Alcaligenes eutrophus
B9 and
Pseudomonas
sp. B13 to 2-Fluorobenzoate as Growth Substrate
Authors: Engesser K.-H. , Schmidt E. , Knackmuss H.-J.
Published: January 2020

Alcaligenes eutrophus
B9 and
Pseudomonas sp.
B13 could be adapted to 2-fluorobenzoate as the sole source of carbon and energy. The ability of the
A. eutrophus
B9 to use this new substrate is clearly based on the defective dihydrodihydroxybenzoate dehydrogenase. Nontoxic 6-fluoro-3,5-cyclohexadiene-1,2-diol-1-carboxylic acid is accumulated instead of 3-fluorocatechol. About 84% of the substrate is dioxygenated to catechol and utilized via the 3-oxoadipate pathway. During continuous adaptation of
Pseudomonas
sp. B13 regioselectivity of dioxygenation of 2-fluorobenzoate is drastically changed in favor of a 1,2-attack. Consequently, approximately 97% of the substrate is utilized via catechol. A three- to fourfold overproduction of key enzymes of the 3-oxoadipate pathway compensates for the slower turnover rates of the fluorinated substrates.
N2O reduction by Vibrio succinogenes
Authors: Yoshinari T
Published: January 2020

Vibrio succinogenes grew anaerobically at the expense of formate oxidation, with nitrous oxide (N2O) serving a terminal oxidant. N2O was quantitatively reduced to dinitrogen (N2). In the presence of 5 x 10(-2) atm (ca. 5 kPa) of acetylene (C2H2), which inhibits the reduction of N2O, growth of V. succinogenes was completely inhibited. Nitrate was reduced to nitrite or to ammonia, depending on the extent of availability of formate, but N2 was not produced by reduction of nitrate. During the reduction of nitrate to ammonia, all eight electrons transported to a molecule of nitrate appeared to be coupled for energy-yielding reactions.
Water-to-Air Fractionation of Bacteria
Authors: Hejkal T. W. , LaRock P. A. , Winchester J. W.
Published: January 2020

Differences in the ability of bacterial species to be transported from water to air by bursting bubbles were investigated. Bubbles were generated in suspensions of mixed bacterial cultures, and the concentration was measured for each species in the top jet drop ejected. This concentration divided by the concentration in the bulk menstruum is the concentration factor (CF). Bubbles were generated 2 cm below the liquid surface, and jet drops with diameters from 34 to 136 μm were studied.
Serratia marinorubra
and
Micrococcus euryhalis
had CFs which were generally 10 to 100 times greater than those of
Escherichia coli, Pseudomonas bathycetes
, and spores of
Bacillus subtilis. P. bathycetes
never had a CF significantly greater than 1 at any drop size, and spores of
B. subtilis
had a maximum CF of 4.
E. coli
had a maximum CF of 6 for 1- or 2-day old cultures, but this increased to 80 when a 5-day-old culture was used. This change in the CF with age of the cells indicates that composition of the cell may be a factor influencing its ability to concentrate in jet drops.
Nitrogen Fixation by Photosynthetic Bacteria in Lowland Rice Culture
Authors: Habte M. , Alexander M.
Published: January 2020

Propanil (3′,4′-dichloropropionanilide) was a potent inhibitor of the nitrogenase activity of blue-green algae (cyanobacteria) in flooded soil, but the herbicide at comparable concentrations was not toxic to rice, protozoa, and nitrogen-fixing bacteria. Ethanol-amended flooded soils treated with propanil exhibited higher rates of nitrogenase activity than those not treated with the herbicide. The enhanced nitrogenase activity in propanil-treated soils was associated with a rise in the population of purple sulfur bacteria, especially of cells resembling
Chromatium
and
Thiospirillum.
By employing propanil and a means of excluding light from the floodwater to prevent the development of phototrophs during rice growth under lowland conditions, the relative activities of blue-green algae, photosynthetic bacteria, and the rhizosphere microflora were determined. The results suggest that the potential contribution of photosynthetic bacteria may be quite high.
Influence of Environmental Factors on Antagonism of Fungi by Bacteria in Soil: Nutrient Levels
Authors: Rosenzweig William D. , Stotzky G.
Published: January 2020

The addition of 0.25, 0.5, or 1.0% glucose to a soil (K) amended with either 6% kaolinite (K6K) or montmorillonite (K6M) or the adjustment of the C/N ratio of the soils from 23/1 to 10/1 with NH
4
NO
3
eliminated the inhibition of
Aspergillus niger
by
Serratia marcescens
, regardless of whether the fungus and bacterium were inoculated into the same or separate sites in the soils. The adjustment of the C/N ratio to 15/1 or of the C/P ratio from 1,000/1 to 100/1 with KH
2
PO
4
did not eliminate the antagonism. However, with the higher glucose and NH
4
NO
3
amendments,
S. marcescens
died out in the K and K6K (but not in the K6M) soils, apparently due to reductions in pH that resulted from the increased metabolism induced by added nutrients. In soils amended with CaCO
3
,
S. marcescens
did not die out, but the inhibition of
A. niger
by
S. marcescens
or
Agrobacterium radiobacter
was eliminated or reduced by the addition of glucose, but not of NH
4
NO
3
, and was influenced by the clay mineralogy and pH of the soils. When NH
4
NO
3
was added to the soils adjusted with CaCO
3
to pH values above 6.0, growth of
A. niger
was inhibited, regardless of whether bacteria were present or not, as a result of the volatilization of NH
3
.
Bacillus cereus
and another species of
Bacillus
did not inhibit
A. niger
under any of the environmental conditions. There was a direct correlation between the degree of inhibition and the rate of glucose utilization by the various bacteria, indicating that the antagonism of
A. niger
by some bacteria in soil was the result primarily of a competition for carbon and that this competition was influenced by other environmental factors, such as pH and clay mineralogy.
Microbial transformation of kepone
Authors: Orndorff S A , Colwell R R
Published: January 2020

Pseudomonas aeruginosa strain KO3 and a mixed aerobic enrichment culture, isolated from sewage sludge lagoon water, were found to aerobically transform the chlorinated insecticide Kepone, yielding monohydro-Kepone. Identification of the product was confirmed by gas chromatography and electron impact mass spectrometry. The mixed culture and P. aeruginosa strain KO3 produced about 4 and 16%, respectively, dihydro-Kepone, determined by cochromatography using authentic standards. Reduced amounts of monohydro-Kepone, compared with the mixed and pure cultures, were produced by James River sediment microorganisms. Kepone was not utilized as a sole carbon or energy source by any of the bacteria or mixed cultures examined in this study.
Interaction Between a Non-Nodulating and an Ineffective Mutant of
Rhizobium trifolli
Resulting in Effective (Nitrogen-Fixing) Nodulation
Authors: Rolfe B. G. , Gresshoff P. M. , Shine J. , Vincent J. M.
Published: January 2020

A noninvasive (non-nodulating) mutant of
Rhizobium trifolii
when mixed with an ineffective (non-nitrogen-fixing) mutant gives rise to effective (nitrogen-fixing) nodules.
Sulfide Production from Cysteine by
Desulfovibrio desulfuricans
Authors: Forsberg C. W.
Published: January 2020

Two rumen nitrate-reducing isolates of
Desulfovibrio desulfuricans
were found to hydrolyze cysteine with the production of sulfide and pyruvate. When cultured on agar medium containing yeast extract with nitrate as the primary electron acceptor and ferrous chloride as the indicator, blackening of colonies occurred. The blackening of colonies appeared sooner and was more intense when either cysteine or sulfate was added to the culture medium with nitrate present.
Assimilation of Lemonade-Processing Wastewater by Yeasts
Authors: Hang Y. D.
Published: January 2020

Of the five species of yeasts examined in shake-flask studies at 30°C, only
Candida utilis
and
Saccharomyces fragilis
gave higher cell yields (>2.5 g /liter) in 32 h and reduced approximately 87% of the biological oxygen demand in lemonade-processing wastewater fortified with 0.05% ammonium sulfate and 0.01% potassium phosphate. The latter, however, settled more rapidly than the former.
Frequent isolation of Edwardsiella tarda and Pleisiomonas shigelloides from healthy Zairese freshwater fish: a possible source of sporadic diarrhea in the tropics
Authors: Van Damme L R , Vandepitte J
Published: January 2020

The intestinal contents of 59 Zairese freshwater fish were examined for the presence of potential human enteric pathogens. Edwardsiella tarda and Plesiomonas shigelloides were isolated from 57 and 59% of them, respectively. For both microorganisms there was a significant difference between the isolation rates from lake and river fish: whereas E. tarda was much more frequently isolated from lake fish than was P. shigelloides, the reverse was observed for river fish. The authors hypothesize that sporadic cases of tropical diarrhea with E. tarda or P. shigelloides can be traced to contact with or consumption of freshwater fish.
Metabolism of Radiolabeled β-Guaiacyl Ether-Linked Lignin Dimeric Compounds by
Phanerochaete chrysosporium
Authors: Weinstein David A. , Krisnangkura Kanit , Mayfield Mary B. , Gold Michael H.
Published: January 2020

Phanerochaete chrysosporium
metabolized the radiolabeled lignin model compounds [γ-
14
C]guaiacylglycerol-β-guaiacyl ether and [4-
methoxy
-
14
C]veratrylglycerol-β-guaiacyl ether (VI) to
14
CO
2
in stationary and in shaking cultures.
14
CO
2
evolution was greater in stationary culture.
14
CO
2
evolution from [γ-
14
C]guaiacyl-glycerol-β-guaiacyl ether and [4-
methoxy
-
14
C]veratrylglycerol-β-guaiacyl ether in stationary cultures was two- to threefold greater when 100% O
2
rather than air (21% O
2
) was the gas phase above the cultures.
14
CO
2
evolution from the metabolism of the substrates occurred only as the culture entered the stationary phase of growth. The presence of substrate levels of nitrogen in the medium suppressed
14
CO
2
evolution from both substrates in stationary cultures. [
14
C]veratryl alcohol and 4-ethoxy-3-methoxybenzyl alcohol were formed as products of the metabolism of VI and 4-ethoxy-3-methoxyphenylglycerol-β-guaiacyl ether, respectively.
Movement of Endotoxin Through Soil Columns
Authors: Goyal Sagar M. , Gerba Charles P. , Lance J. Clarence
Published: January 2020

Land treatment of wastewater is an attractive alternative to conventional sewage treatment systems and is gaining widespread acceptance. Although land application systems prevent surface water pollution and augment the available water supplies, the potential dangers to human health should be evaluated. Since sewage may contain high amounts of bacterial endotoxin, the removal of endotoxin from sewage by percolation through soil was investigated. It was found that 90 to 99% of the endotoxin was removed after travel of sewage through 100 to 250 cm of loamy sand soil. When distilled water was allowed to infiltrate into the soil to simulate rainfall, the endotoxin was mobilized and moved in a concentrated band through the soil column. On testing samples from actual land treatment sites, as much as 480 ng of endotoxin per milliliter was found in some groundwater samples. The presence of endotoxin in potable water is known to be a potential problem under some circumstances, but the importance of endotoxin in water supplies has not been fully assessed. Therefore, the design, operation, and management of land application systems should take into account the fate of endotoxin in groundwater beneath the sites.
Impairment of phagocytosis by heterophils from chickens during ochratoxicosis
Authors: Chang C F , Hamilton P B
Published: January 2020

The effect of graded concentrations of dietary ochratoxin A (0, O.5, 1.0, 2.0, 4.0, and 8.0 microgram/g of diet) on the in vitro phagocytic, locomotory, and bactericidal capacities of heterophils from broiler chickens was investigated. Both the percentage and the mean phagocytic activities were decreased significantly (P less than 0.05) at 4.0 and 8.0 microgram/g. Both directed and undirected locomotion of heterophila was impaired significantly at the same concentrations. A crossover experiment revealed that the reduced percentage of phagocytosis was associated with the heterophil itself and not with a serum factor such as complement. Heterophila from birds that consumed 4.0 microgram/g were not impaired in ability to kill engulfed bacteria.
Effect of temperature on mineralization by heterotrophic bacteria
Authors: Tison D L , Pope D H
Published: January 2020

When pure cultures of the bacteria Pseudomonas fluorescens (a psychrotroph), Escherichia coli (a mesophile), and SRL 261 (a thermophile) were shifted away from temperatures to which they were adapted, the percentage of substrate mineralized increased (percent mineralized = [substrate respired to CO2]/substrate respired to CO2 + substrate incorporated into biomass] X 100). The increase in the percent mineralized was larger for larger temperature shifts. Similar responses were observed when natural heterotrophic bacterial populations from sediments of Lake George, N.Y., and a thermophilic algal-bacterial mat community at the Savannah River Plant, Aiken, S.C., were subjected to temperature shifts. These results suggest that an increase in the percent mineralized may be an indication of thermal stress in bacterial populations.
Growth characteristics, cytopathic effect in cell culture, and virulence in mice of 36 type strains belonging to 19 different Acanthamoeba spp
Authors: De Jonckheere J F
Published: January 2020

A total of 36 strains belonging to 19 different species of Acanthamoeba were compared for temperature tolerance, ability to grow in an axenic medium, cytopathic effect in Vero cell culture, and virulence in mice. Pathogenic strains appeared to belong to different species, whereas pathogenic and nonpathogenic strains occurred in one species. Although growth at high temperatures and readiness to grow axenically indicated a potential for pathogenicity, each such strain had to be tested in cell cultures or laboratory mice to determine whether or not it was virulent. This study was not intended to differentiate Acanthamoeba spp., but to provide methods to be used for the specific isolation and identification of pathogenic Acanthamoeba strains.
Microbial Production of 4,4′-Dihydroxybiphenyl: Biphenyl Hydroxylation by Fungi
Authors: Schwartz Robert D. , Williams A. L. , Hutchinson D. B.
Published: January 2020

Of 15 species of fungi examined for their ability to hydroxylate biphenyl, 10 produced 4-hydroxybiphenyl. Seven of the 10 also produced 4,4′-dihydroxybiphenyl. The most efficient strains,
Absidia pseudocylindrospora
NRRL 2770 and
Absidia
sp. NRRL 1341, were more closely examined to determine their growth characteristics and the kinetics of biphenyl hydroxylation in batch fermentation. In the absence of biphenyl,
A. pseudocylindrospora
2770 and
Absidia
sp. 1341 grew about as rapidly and efficiently in a defined glucose minimal medium as in a complex medium. Substrate yield coefficients for glucose in both media were 0.4 to 0.5 g of biomass per g of glucose, and the specific growth rate was about 0.17 h
−1
(doubling time, about 4 h). In this unoptimized system, 10 to 15 g of biomass per liter (dry weight) could be produced, using a defined salt solution and glucose as sole carbon and energy source. In the presence of biphenyl, growth was inhibited, more so for strain 1341 than for strain 2770. However, the specific activity for biphenyl hydroxylation (milligrams of biphenol per gram of biomass) was about 3.5 times greater for strain 1341. Furthermore, biphenyl hydroxylation appeared to require the presence of an oxidizable carbon and energy source (and perhaps growth) to proceed and, at least for strain 1341, hydroxylation seemed to be more efficient in the complex medium.
Differential carbohydrate media and anaerobic replica plating techniques in delineating carbohydrate-utilizing subgroups in rumen bacterial populations
Authors: Leedle J A , Hespell R B
Published: January 2020

A basal (BC) medium devoid of added carbohydrates, a complete (CC) medium containing nine carbohydrates were developed for enumerating rumen bacteria. The colony counts on the BC medium were 85 to 100% of those obtained on the CC medium. These colonies were pinpoint size (less than or equal to mm in diameter) but increased in size (2 to 5 mm in diameter) when carbohydrates were subsequently added. With the CC medium or other media tested, the colony counts were 20 to 50% higher on plates than on roll tubes and were about 35% of the direct cell counts. The lower colony counts on roll tubes were shown to result primarily from the loss of viability due to heat stress. The DC media were found by plating techniques to be suitable for differentiating mixed rumen bacterial populations into subgroups based upon carbohydrate utilization as shown by differences in subgroup profiles found within solid and liquid fractions of rumen contents, within rumen contents from animals fed high-forage and high-grain diets, and by correct colony formations by pure cultures of rumen bacteria on appropriate DC media. With simple modifications and use of an anaerobic glove box, replica plating methods and the CC and DC media were found to be a suitable means of rapidly determining the range of utilizable carbohydrate energy sources of rumen bacteria.
Staphylococcus aureus in rural drinking water
Authors: LeChevallier M W , Seidler R J
Published: January 2020

Coagulase-positive Staphylococcus aureus was isolated from over 6% of 320 rural drinking water specimens. Well water was the most common source examined. The presence of S. aureus was not found to correlate with the presence of coliform bacteria. Strains of Staphylococcus that produced enterotoxin A were found in 40% of the samples containing S. aureus. Additional studies showed that faucet aerator screens were common sources of high cell densities of S. aureus.
Distribution of Clostridium botulinum
Authors: Huss H H
Published: January 2020

The distribution of Clostridium botulinum in the natural environments of Denmark, The Faroe Islands, Iceland, Greenland, and Bangladesh was examined. A total of 684 samples were tested. Type E was found in 90% of samples from the aquatic environment of Denmark, including sediments from young artificial lakes, and in 86% of samples from the marine environment of Greenland. Type E was not found in Danish cultivated soil and woodlands, including cultivated soil from reclaimed sea beds, but type B was frequently demonstrated in these environments. C. botulinum types A, B, or E were found in 2.6% of samples from the environments of the Faroe Islands and Iceland, whereas types C or D were demonstrated in 42% of samples from Bangladesh. The incidence of type E in aquatic sediments was not related to general industrial pollution or a high content of rotting vegetation. Fish or a rich aquatic fauna, on the other hand, appeared to contribute to a high incidence of type E. Based on these findings, it is suggested that type E is a true aquatic organism, because this environment offers the best conditions for survival of the spore in nature. It is further suggested that its presence in aquatic bottom deposits is based on sedimentation after proliferation in the carrion of the aquatic fauna and dissemination by water currents and migrating fish.
Relationship Between the Sterol Content of Yeast Cells and Their Fermentation Activity in Grape Must
Authors: Larue F. , Lafon-Lafourcade S. , Ribereau-Gayon P.
Published: January 2020

In grape must of high sugar concentration, yeast growth, the viability rate of “resting” yeast cells, and fermentation activity were stimulated under certain conditions of aeration and temperature. This stimulation might be interpreted as being a result of the yeast cell sterol content. The addition of certain sterols to the fermenting medium was able to increase this sterol content. According to aeration conditions of the medium, which determined the sterol content of yeasts, the sterols added in the medium acted as (i) growth factors, (ii) fermentation inhibitors, and (iii) survival factors for the yeast.
Bacterial inhibitory effects of nitrite: inhibition of active transport, but not of group translocation, and of intracellular enzymes
Authors: Yarbrough J M , Rake J B , Eagon R G
Published: January 2020

Nitrite inhibited active transport of proline in Escherichia coli but not group translocation of sugar via the phosphoenolpyruvate:phosphotransferase system. These results were consistent with previous results that nitrite inhibits active transport, oxygen uptake, and oxidative phosphorylation in aerobic bacteria. Nitrite also inhibited aldolase (EC 4.1.2.13) from E. coli, Pseudomonas aeruginosa, Streptococcus faecalis, and rabbit muscle. Thus, these various data showed that nitrite has more than one site of attack in the bacterial cell. These data also indicated that nitrite is inhibitory to a wide range of physiological types of bacteria.
Identification of averantin as an aflatoxin B1 precursor: placement in the biosynthetic pathway
Authors: Bennett J W , Lee L S , Shoss S M , Boudreaux G H
Published: January 2020

A new blocked mutant of Aspergillus parasiticus produces no detectable aflatoxin B1, but accumulates several polyhydroxyanthraquinones. One of these pigments was identified as averantin. This is the first report of its formation by A. parasiticus. Radiotracer studies with [14C]averantin showed that 15.3% of label from averantin was incorporated into aflatoxin B1. This incorporation was blocked by dichlorvos. With radiotracers and other mutants, averantin was placed after norsolorinic acid and before averufin in the biosynthetic pathway in which the general steps are norsolorinic acid leads to averantin leads to averufin leads to versiconal hemiacetal acetate leads to versicolorin A leads to sterigmatocystin leads to aflatoxin B1.
Nitrite and Nitrous Oxide Accumulation During Denitrification in the Presence of Pesticide Derivatives
Authors: Bollag Jean-Marc , Kurek Ewa J.
Published: January 2020

Temporary accumulation of nitrite and nitrous oxide was observed in soil incubated under anaerobic conditions when derivatives of the insecticide chlordimeform [(
N
-4-chloro-
o
-tolyl)-
N
′,
N
′ -dimethylformamidine] were added. Chlordimeform did not affect the denitrification process, but
N
-formyl-4-chloro-
o
-toluidine and 4-chloro-
o
-toluidine caused an inhibition as determined by the accumulation of nitrite and nitrous oxide. A simultaneous application of the insecticide and its derivatives resulted in a stronger inhibitory effect than the application of each compound separately. Aniline intermediates of other pesticides also inhibited denitrification in soil, and they proved to be more effective than their parent compound.
Deoxyribonucleic Acid Repair in
Bacillus subtilis
: Development of Competent Cells into a Tester for Carcinogens
Authors: Yasbin Ronald E. , Miehl Rosemarie
Published: January 2020

The development of competent transformed
Bacillus subtilis
into a tester system for carcinogens is described. Precocious or noninduced activation of SOS functions occur in competent cells. Thus, lower doses or concentrations of SOS inducing agents are needed to cause cell death due to indigenous prophage activation and lysis of bacteria. The two known defective prophages in
B. subtilis
enhance the sensitivity of competent cells to the carcinogens ultraviolet light, mitomycin C, and methyl methanesulfonate. However, these same cells have no enhanced sensitivity for the non-carcinogenic ethyl methanesulfonate or for nalidixic acid. Therefore, competent
B. subtilis
appear to be a sensitive tester for carcinogens.
Populations of Methane-Producing Bacteria and In Vitro Methanogenesis in Salt Marsh and Estuarine Sediments
Authors: Jones William J. , Paynter Malcolm J. B.
Published: January 2020

Most probable numbers (MPNs) of methanogens in various salt marsh and estuarine sediments were determined with an anaerobic, habitat-simulating culture medium with 80% H
2
plus 20% CO
2
as substrate. Average MPNs for the short
Spartina
(SS) marsh sediments of Sapelo Island, Ga., were maximal at the 5- to 7-cm depth (1.2 × 10
7
/g of dry sediment). Populations decreased to approximately 880/g of dry sediment at the 34- to 36-cm depth. There was no significant difference between summer and winter populations. In tall
Spartina
(TS) marsh sediments, average populations were maximal (1.2 × 10
6
/g of dry sediment) in the upper 0- to 2-cm zone; populations from the 5- to 36-cm zones were similar (average of 9 × 10
4
/g of dry sediment). Methanogenic populations for TS sediments of James Island Creek marsh, Charleston, S.C., were similar (average of 3 × 10
6
/g of dry sediment) for all depths tested (0 to 22 cm), which was comparable to the trend observed for TS sediments at Sapelo Island, Ga. Sediment grab samples collected along a transect of James Island Creek and its adjacent
Spartina
marsh had MPNs that were approximately 20 times greater for the region of
Spartina
growth (average of 10
6
/g of dry sediment) compared with the channel (approximately 5 × 10
4
methanogens per g of dry sediment). A similar trend was found at Pawley's Island marsh, S.C., but populations were approximately one order of magnitude lower. In vitro rates of methanogenesis with SS sediments incubated under 80% H
2
-20% CO
2
showed that the 5- to 7-cm region exhibited maximal activity (51 nmol of CH
4
g
−1
h
−1
), which was greater than rates for sediments above and below this depth. SS sediment samples (5 to 7 cm) incubated under 100% N
2
and supplemented with formate exhibited rates of methanogenesis similar to those generated by samples under 80% H
2
-20% CO
2
. Replacing the N
2
atmosphere with H
2
resulted in an eightfold decrease in the rate of methanogenesis. In vitro methanogenic activity by TS salt marsh sediments, incubated under 80% H
2
-20% CO
2
, was similar for all depths tested (0 to 22 cm). TS sediment samples (0 to 7 cm) supplemented with formate and incubated under 100% N
2
had greater rates of methanogenesis compared with unsupplemented samples.
Penitrem A and Roquefortine Production by
Penicillium commune
Authors: Wagener R. E. , Davis N. D. , Diener U. L.
Published: January 2020

Extracts of
Penicillium commune
, a fungus isolated from cottonseed, showed biological activity in day-old cockerels. Two neurotoxic metabolites were isolated and identified as penitrem A and roquefortine. This is the first report of roquefortine being produced by a fungus other than
Penicillium roqueforti
as well as the first report of penitrem A and roquefortine being produced in the same culture. Production of these toxins on liquid media and cottonseed was determined.
Immunofluorescent Assay for the Marine Ammonium-Oxidizing Bacterium
Nitrosococcus oceanus
Authors: Ward B. B. , Perry M. J.
Published: January 2020

Nitrification is one of the important microbiological transformations of nitrogen in the ocean. Traditional enrichment-culture methods for enumerating the autotrophic bacteria which oxidize ammonium to nitrite are very time consuming (months) and are believed to seriously underestimate natural abundances. A fluorescent-antibody assay for a marine ammonium-oxidizing bacterium was developed to provide a rapid and direct means of identifying these microorganisms. Antibodies to
Nitrosococcus oceanus
were prepared and tested against pure cultures of marine, freshwater, and soil ammonium oxidizers and against bacteria from natural seawater samples. Cell counts of culture samples determined by the fluorescent-antibody assay agreed with hemacytometer and acridine orange counts. Our results demonstrated that the immunofluorescent assay is a powerful tool for the detection of
Nitrosococcus
in the marine environment.
Small pectinolytic spirochetes from the rumen
Authors: Ziołecki A , Wojciechowicz M
Published: January 2020

Two strains of small spirochetes utilizing pectin as sole source of energy for growth were isolated from the rumen of cattle and partially characterized. The pectinolytic enzyme produced by one of the organisms was classified as a poly-1,4-alpha-D-galacturonide lyase (EC 4.2.2.2). A pectinesterase (EC 3.1.1.11) was also produced.
Stability of the Plasma Membrane in
Saccharomyces rouxii
and Its Relationship to Glucose Tolerance
Authors: Moran James W. , Witter Lloyd D.
Published: January 2020

The stability of spheroplasts from the osmotrophic yeast
Saccharomyces rouxii
was studied in buffered solutions of mannitol and glucose. The plasma membranes from cells grown in high glucose concentrations were more stable to osmotic lysis than were membranes from cells grown in lower glucose concentrations. Mannitol was a better osmotic stabilizer than glucose, except when the cells were grown in a high glucose concentration. Spheroplasts from a glucose tolerant-deficient mutant were much less stable than the corresponding spheroplasts from the parent strain, especially when suspended in glucose solutions. These results suggest an involvement of the plasma membrane in the glucose-tolerant mechanism of
S. rouxii
.
Digestion of epithelial tissue of the rumen wall by adherent bacteria in infused and conventionally fed sheep
Authors: Dinsdale D , Cheng K J , Wallace R J , Goodlad R A
Published: January 2020

Comparisons were made, by light and electron microscopy, of the rumen epithelium of sheep fed conventionally and fed by infusion of volatile fatty acids and buffer into the rumen and casein into the abomasum. Similar bacterial colonization of the epithelium was observed in each case. The mitotic index of epithelial cells in infused sheep was high, as it was in barley-fed animals, while the mitotic index of cells from animals receiving roughage was low. The bacterial flora appeared to be actively digesting the epithelial cells. The fate of sloughed epithelial cells in the rumen fluid of sheep fed by infusion was also studied. The sloughed cells were rapidly digested, probably by their attached flora of facultatively anaerobic, highly proteolytic bacteria, leaving abundant highly keratinized remnants in rumen fluid. The importance of epithelial cell turnover and of proteolysis by partially facultative bacteria in the rumen is discussed.
Isolation of
Methanobacterium bryantii
from a Deep Aquifer by Using a Novel Broth-Antibiotic Disk Method
Authors: Godsy E. M.
Published: January 2020

Methanobacterium bryantii
was isolated from a mixed-culture enrichment of a water sample from a deep aquifer by using a complex growth medium supplemented with antibiotic susceptibility disks to inhibit the growth of non-methanogenic bacteria.
Acetylene Reduction Assay for Nitrogenase Activity: Gas Chromatographic Determination of Ethylene Per Sample in Less Than One Minute
Authors: David K. A. V. , Apte S. K. , Banerji A. , Thomas Joseph
Published: January 2020

Ammoniacal silver nitrate (10 mg/ml) was added to terminate acetylene reduction assays used to measure nitrogenase activity. Silver nitrate quantitatively precipitated acetylene as the carbide salt, but did not affect the ethylene formed. The vials containing ethylene can be analyzed gas chromatographically at the rate of about 13 samples in 10 min.
Sulfhydrolase Activity in Sediments of Wintergreen Lake, Kalamazoo County, Michigan
Authors: King Gary M. , Klug Michael J.
Published: January 2020

The hydrolysis of
p
-nitrophenyl sulfate,
p
-nitrocatechol sulfate, and [
35
S]sodium dodecyl sulfate was examined in anoxic sediments of Wintergreen Lake, Michigan. Significant levels of sulfhydrolase activity were observed in littoral, transition, and profundal sediment samples. Rates of sulfate formation suggest that the sulfhydrolase system would represent a major source of sulfate within these sediments. Sulfate formed by ester sulfate hydrolysis can support dissimilatory sulfate reduction as shown by the incorporation of
35
S from labeled sodium dodecyl sulfate into H
2
35
S. Sulfhydrolase activity varied with sediment depth, was greatest in the littoral zone, and was sensitive to the presence of oxygen. Estimations of ester sulfate concentrations in sediments revealed large quantities of ester sulfate (∼30% of total sulfur). Both total sulfur and ester sulfate concentrations varied with the sediment type and were two to three orders of magnitude greater than the inorganic sulfur concentration.
Formation of 4-hydroxyochratoxin A from ochratoxin A by rat liver microsomes
Authors: St�rmer F C , Pedersen J I
Published: January 2020

Hydroxyochratoxin A was isolated and identified from the urine of rats after injection with ochratoxin A. By incubating ochratoxin A with rat liver microsomes and reduced nicotinamide adenine dinucleotide phosphate, one major (90%) and two minor metabolites, more polar than ochratoxin A, were formed. Thin-layer chromatography revealed that the major metabolite had Rf values identical to those of hydroxyochratoxin A in six different solvent systems. Formation of the metabolites in vitro was inhibited by carbon monoxide and by metyrapone, and the rate of formation increased after pretreatment of the rats with phenobarbital. A type I spectrum appeared upon binding of ochratoxin A to microsomes with a spectral dissociation constant (Ks) of 37.6 microM. These findings strongly suggest the involvement of a cytochrome P-450 in the hydroxylation of ochratoxin A by rat liver microsomes. Apparent Km and Vmax values for the formation of hydroxyochratoxin A were determined to 50 microM and 5.5 nmol/mg of protein per h, respectively.
Distribution and Identification of Luminous Bacteria from the Sargasso Sea
Authors: Orndorff S. A. , Colwell R. R.
Published: January 2020

Vibrio fischeri
and
Lucibacterium harveyi
constituted 75 of the 83 luminous bacteria isolated from Sargasso Sea surface waters.
Photobacterium leiognathi
and
Photobacterium phosphoreum
constituted the remainder of the isolates. Luminescent bacteria were recovered at concentrations of 1 to 63 cells per 100 ml from water samples collected at depths of 160 to 320 m. Two water samples collected at the thermocline yielded larger numbers of viable, aerobic heterotrophic and luminous bacteria. Luminescent bacteria were not recovered from surface microlayer samples. The species distribution of the luminous bacteria reflected previously recognized growth patterns; i.e.,
L. harveyi
and
V. fischeri
were predominant in the upper, warm waters (only one isolate of
P. phosphoreum
was obtained from surface tropical waters).