bluuebunny/crossref_metadata_2025 huggingface dataset:
Ethanol from Whey: Continuous Fermentation with a Catabolite Repression-Resistant
Saccharomyces cerevisiae
Mutant
Authors: Terrell Scott L. , Bernard Alain , Bailey Richard B.
Published: January 2020

An alternative method for the conversion of cheese whey lactose into ethanol has been demonstrated. With the help of continuous-culture technology, a catabolite repression-resistant mutant of
Saccharomyces cerevisiae
completely fermented equimolar mixtures of glucose and galactose into ethanol. The first step in this process was a computer-controlled fed-batch operation based on the carbon dioxide evolution rate of the culture. In the absence of inhibitory ethanol concentrations, this step allowed us to obtain high biomass concentrations before continuous fermentation. The continuous anaerobic process successfully incorporated a cell-recycle system to optimize the fermentor productivity. Under conditions permitting a low residual sugar concentration (≤1%), maximum productivity (13.6 g liter
−1
h
−1
) was gained from 15% substrate in the continuous feed at a dilution rate of 0.2 h
−1
. Complete fermentation of highly concentrated feed solutions (20%) was also demonstrated, but only with greatly diminished fermentor productivity (5.5 g liter
−1
h
−1
).
Methanogenic Activity and Structural Characteristics of the Microbial Biofilm On a Needle-Punched Polyester Support
Authors: Harvey Martin , Forsberg Cecil W. , Beveridge Terry J. , Pos Jack , Ogilvie John R.
Published: January 2020

In a downflow stationary fixed-film anaerobic reactor receiving a swine waste influent, few bacteria were observed to be tightly adherent to the surfaces of the needle-punched polyester support material. However, there was a morphologically complex, dense population of bacteria trapped within the matrix. Frequently large microcolonies of a uniform morphological type of bacteria were observed. These were particularly evident for methanosarcina-like bacteria which grew forming large aggregates of unseparated cells. Leafy deposits of electron-dense, calcium- and phosphorus-enriched material coated the polyester matrix and some cells. As the biofilm matured there was more extensive mineral deposition which completely entrapped cells. The entrapped cells appeared to autolyze, and many were partially degraded. Further impregnation of the matrix with minerals and apparent cell death may eventually have a deleterious effect on the methanogenic activity of the biofilm.
High-Gravity Brewing: Effects of Nutrition on Yeast Composition, Fermentative Ability, and Alcohol Production
Authors: Casey Gregory P. , Magnus Carol A. , Ingledew W. M.
Published: January 2020

A number of economic and product quality advantages exist in brewing when high-gravity worts of 16 to 18% dissolved solids are fermented. Above this level, production problems such as slow or stuck fermentations and poor yeast viability occur. Ethanol toxicity has been cited as the main cause, as brewers' yeasts are reported to tolerate only 7 to 9% (vol/vol) ethanol. The inhibitory effect of high osmotic pressure has also been implicated. In this report, it is demonstrated that the factor limiting the production of high levels of ethanol by brewing yeasts is actually a nutritional deficiency. When a nitrogen source, ergosterol, and oleic acid are added to worts up to 31% dissolved solids, it is possible to produce beers up to 16.2% (vol/vol) ethanol. Yeast viability remains high, and the yeasts can be repitched at least five times. Supplementation does not increase the fermentative tolerance of the yeasts to ethanol but increases the length and level of new yeast cell mass synthesis over that seen in unsupplemented wort (and therefore the period of more rapid wort attenuation). Glycogen, protein, and sterol levels in yeasts were examined, as was the importance of pitching rate, temperature, and degree of anaerobiosis. The ethanol tolerance of brewers' yeast is suggested to be no different than that of sake or distillers' yeast.
Screening Wood Decayed by White Rot Fungi for Preferential Lignin Degradation
Authors: Blanchette Robert A.
Published: January 2020

A screening procedure in which scanning electron microscopy was used indicated that 26 white rot fungi selectively removed lignin from various coniferous and hardwood tree species. Delignified wood from field collections had distinct micromorphological characteristics that were easily differentiated from other types of decay. The middle lamella was degraded, and the cells were separated from one another. Secondary cell wall layers that remained had a fibrillar appearance. Chemical analyses of delignified wood indicated that the cells were composed primarily of cellulose. Only small percentages of lignin and hemicellulose were evident. Delignified wood was not uniformly distributed throughout the decayed wood samples. White-pocket and white-mottled areas of the various decayed wood examined contained delignified cells, but adjacent wood had a nonselective removal of lignin where all cell wall components had been degraded simultaneously. This investigation demonstrates that selective delignification among white rot fungi is more prevalent than previously realized and identifies a large number of fungi for use in studies of preferential lignin degradation.
Microbiological contamination of raw materials for large-volume parenterals
Authors: Baggerman C , Kannegieter L M
Published: January 2020

A wide range of raw materials used for the production of large-volume parenterals were tested for their content of bacteria, molds, yeasts, and endotoxins. All raw materials were relatively free of microorganisms, although some mannitol samples contained relatively high amounts of endotoxin. The low endotoxin content of the other raw materials did not require the use of depth filters to remove endotoxins to prepare pyrogen-free infusion fluids.
Coliphages as indicators of enteroviruses
Authors: Stetler R E
Published: January 2020

Coliphages were monitored in conjunction with indicator bacteria and enteroviruses in a drinking-water plant modified to reduce trihalomethane production. Coliphages could be detected in the source water by direct inoculation, and sufficient coliphages were detected in enterovirus concentrates to permit following the coliphage levels through different water treatment processes. The recovery efficiency by different filter types ranged from 1 to 53%. Statistical analysis of the data indicated that enterovirus isolates were better correlated with coliphages than with total coliforms, fecal coliforms, fecal streptococci, or standard plate count organisms. Coliphages were not detected in finished water.
Purification and partial characterization of Flavotoxin A
Authors: Hu W J , Zhang G S , Chu F S , Meng H D , Meng Z H
Published: January 2020

A heat-resistant, low-molecular-weight toxin was isolated from semisolid potato dextrose agar medium after inoculation with Flavobacterium farinofermentans sp. nov., which was isolated from fermented corn meal that caused some outbreaks of food poisoning in China. The toxin was purified by solvent partition, Sephadex LH-20 gel filtration, and C-18 reversed-phase column chromatography. Thin-layer chromatography and high-pressure liquid chromatographic methods were developed for the identification and analysis of the toxin. The purified toxin exhibited a single spot in thin-layer chromatography and a single peak in high-pressure liquid chromatography and had adsorption maxima at 232 and 267 nm. Mass spectral analysis indicated a molecular weight of 169 with an experimental formula of C9H13O3. The 50% lethal dose of purified toxin in mice (oral) was less than 6.84 mg/kg, but greater than 0.68 mg/kg. Postmortem examination showed that the mice died of some type of neurological and cardiovascular system toxicity. The name Flavotoxin A is being assigned to the toxin.
Structure of Cell Wall and Extracellular Mannans from
Saccharomyces rouxii
and Their Relationship to a High Concentration of NaCl in the Growth Medium
Authors: Hamada Takashi , Noda Fumio , Hayashi Kazuya
Published: January 2020

Cells of
Saccharomyces rouxii
(a salt-tolerant yeast) were grown in the presence of two levels of NaCl, 0 and 15%. Mannans obtained from both the cell walls and culture filtrates (extracellular) were examined. Yields based on the dry weight of cells demonstrated that the levels of both cell wall and extracellular mannans were lower when cells were grown in the presence of 15% NaCl. However, the carbohydrate and protein contents of the mannan preparations were not altered. The cell wall mannans obtained from the two growth conditions had similar molecular weights, whereas the extracellular mannans had different molecular weight distributions. Structural analyses showed that the cell wall and extracellular mannans had similar structures. Both had an α1-6-linked backbone to which single mannose and mannobiose units were connected as side chains, predominantly by α1-2 linkages. The mannans also contained mannosyloligosaccharides, mannotriose, mannobiose, and mannose attached to protein through an
O
-glycosidic bond. The molecular structure of the cell wall mannans remained unchanged at both levels of NaCl. However, in the presence of 15% NaCl, the side chains consisting of a mannobiose unit were slightly reduced.
Human pathogenic viruses at sewage sludge disposal sites in the Middle Atlantic region
Authors: Goyal S M , Adams W N , O'Malley M L , Lear D W
Published: January 2020

Human enteric viruses were detected in samples of water, crabs, and bottom sediments obtained from two sewage sludge disposal sites in the Atlantic Ocean. Viruses were isolated from sediments 17 months after the cessation of sludge dumping. These findings indicate that, under natural conditions, viruses can survive for a long period of time in the marine environment and that they may present potential public health problems to humans using these resources for food and recreation. The isolation of viruses in the absence of fecal indicator bacteria reinforces previous observations on the inadequacy of these bacteria for predicting the virological quality of water and shellfish.
Variants of the Obligate Methanotroph Isolate 761M Capable of Growth on Glucose in the Absence of Methane
Authors: Zhao Shu-Jie , Hanson R. S.
Published: January 2020

Isolate 761M is an unusual type I methanotroph that possesses a complete tricarboxylic acid cycle. Variants of this methanotroph that were capable of growth with methanol (isolate 761AR) or glucose (isolate 761H) have been isolated. Cultures of isolate 761H grown with glucose and casein hydrolysate as the sole carbon and energy sources retained the ability to grow on methane, contained methane monooxygenase and 3-hexulose phosphate synthase, and possessed intracytoplasmic membranes similar to those found in thin sections of isolate 761M grown on methane. Methane monooxygenase was also present in cultures of isolate 761AR grown on methanol and casein hydrolysate.
Reovirus removal and inactivation by slow-rate sand filtration
Authors: McConnell L K , Sims R C , Barnett B B
Published: January 2020

Laboratory column studies were conducted at the Utah Water Research Laboratory, Logan, Utah, to evaluate reovirus removal from drinking water supplies by slow-rate sand filtration (SSF). Columns, constructed to simulate a full-scale SSF field operation, were inoculated with reovirus at ca. 1,000-times-greater concentrations than those typically found in domestic sewage. Reovirus removal and inactivation were investigated as functions of filter maturity and other filter sand characteristics. Reovirus removal studies demonstrated that the SSF process is capable of reducing reovirus in influent water by a minimum of 4 log concentration units under certain conditions of water quality, flow rate, and sand bed construction. Infectious reovirus was not detected in effluent samples from any of the sand beds studied, after inoculation of the SSF columns; therefore, removal efficiencies were not affected significantly by characteristics, including age, of the two filter sands evaluated. Studies conducted with radioactively labeled reovirus demonstrated that reovirus removed from influent water was distributed throughout the entire length of the filter beds. Concentrations of reovirus in the filter sands decreased with increasing bed depth. The greatest removal occurred in the top few centimeters of all sand beds. No infectious reovirus could be detected in clean or mature sand bed media, indicating that reoviruses were inactivated in the filter.
Comparative Studies of Extracellular Fungal Laccases
Authors: Bollag Jean-Marc , Leonowicz Andrzej
Published: January 2020

Various basidiomycetes, ascomycetes, and deuteromycetes, grown in a sugar-rich liquid medium, were compared for laccase-producing ability and for the inducing effect of 2,5-xylidine on laccase production. Clear stimulation of the extracellular enzyme formation by xylidine was obtained in the cultures of
Fomes annosus, Pholiota mutabilis, Pleurotus ostreatus
, and
Trametes versicolor
, whereas
Rhizoctonia praticola
and
Botrytis cinerea
were not affected by the xylidine, and in the case of
Podospora anserina
a decrease in laccase activity was observed. The laccases were purified, and electrophoresis on polyacrylamide gels indicated a particular pattern for each laccase. The bands of the induced forms appeared only with basidiomycetes. The optimal pH of
R. praticola
laccase was in the neutral region, whereas the optima of all the other exolaccases were significantly lower (between pH 3.0 and 5.7). All laccases oxidized the methoxyphenolic acids under investigation, but there existed quantitative differences in oxidation efficiencies which depended on pH and on the nature (noninduced or induced) of the enzyme. The sensitivity of all enzymes to inhibitors did not differ considerably.
Viability of pathogenic and nonpathogenic free-living amoebae in long-term storage at a range of temperatures
Authors: Biddick C J , Rogers L H , Brown T J
Published: January 2020

The long-term storage of pathogenic and nonpathogenic strains of both Naegleria and Acanthamoeba spp. were tested on Page amoeba saline agar slopes for 24 months at room temperature and for 8 months at -10, 4, 10, and 15 degrees C. Acanthamoeba strains showed better survival potential than Naegleria strains, particularly when they were stored at temperatures equal to or lower than room temperature.
Drug-resistant bacteria in Continental Shelf sediments
Authors: Goyal S M , Adams W N
Published: January 2020

Fecal indicator bacteria were isolated from water and sediment samples obtained from a sewage sludge disposal site in the Middle Atlantic. Some were found to be resistant to several antimicrobial agents. Isolation of these microbes 30 months after cessation of sludge dumping indicates their survivability in the environment.
Novel
Pseudomonas
Plasmid Involved in Aniline Degradation
Authors: Anson John G. , Mackinnon Graeme
Published: January 2020

A plasmid of ca. 100 kilobases was detected in a
Pseudomonas
species which was isolated from soil by growth on aniline as the sole carbon and energy source. The plasmid was shown to be involved in aniline metabolism.
Homoacetogenic Fermentation of Cellulose by a Coculture of
Clostridium thermocellum
and
Acetogenium kivui
Authors: Le Ruyet P. , Dubourguier H. C. , Albagnac G.
Published: January 2020

Interrelationships between methanogens and fermentative or hydrolytic bacteria are well documented; however, such cocultures do not allow a complete fermentation shift to a peculiar metabolite. We describe here a new stable association between
Clostridium thermocellum
and
Acetogenium kivui
which converts 1 mol of cellulose (anhydroglucose equivalent) into 2.7 mol of acetate.
Properties of Malolactic Activity Purified from
Leuconostoc oenos
ML34 by Affinity Chromatography
Authors: Spettoli Paolo , Nuti Marco Paolo , Zamorani Arturo
Published: January 2020

Malolactic activity from
Leuconostoc oenos
ML34 is tightly associated with lactic dehydrogenase. A simple and fast procedure, involving affinity chromatography on agarose-hexane-NAD (Agnad), was used to separate malolactic activity from lactic dehydrogenase and other proteins. The yield was ca. 86%, the purification was 5.2-fold, and the

K
m

values for
l
-malate, NAD
+
and Mn
2+
were 2.8, 0.13, and 0.028 mM, respectively, at a pH optimum of 5.8.
Inhibitory effect of sterigmatocystin and 5,6-dimethoxysterigmatocystin on ATP synthesis in mitochondria
Authors: Kawai K , Nakamaru T , Nozawa Y , Maebayashi Y , Yamazaki M , Natori S
Published: January 2020

The inhibitory effects of sterigmatocystin, O-methylsterigmatocystin, and 5,6-dimethoxysterigmatocystin on the ATP synthesis system in mitochondria were compared with that of aflatoxin B1, which disturbs the respiratory chain in mitochondria. Sterigmatocystin and 5,6-dimethoxysterigmatocystin were found to uncouple the oxidative phosphorylation process without causing depression of state 3 respiration. O-Methylsterigmatocystin did not exhibit uncoupling activity at the limited concentrations tested (due to its low solubility in an aqueous system). These compounds, as well as aflatoxin B1, elicited neither pseudo-energized nor energized swelling of mitochondria and did not inhibit Ca2+-induced swelling of mitochondria.
Evolution of Yeasts and Lactic Acid Bacteria During Fermentation and Storage of Bordeaux Wines
Authors: Fleet G. H. , Lafon-Lafourcade S. , Rib�reau-Gayon P.
Published: January 2020

The levels of yeasts and lactic acid bacteria that naturally developed during the vinification of two red and two white Bordeaux wines were quantitatively examined. Yeasts of the genera
Rhodotorula, Pichia, Candida
, and
Metschnikowia
occurred at low levels in freshly extracted grape musts but died off as soon as fermentation commenced.
Kloeckera apiculata (Hanseniaspora uvarum), Torulopsis stellata
, and
Saccharomyces cerevisiae
, the dominant yeasts in musts, proliferated to conduct alcoholic fermentation.
K. apiculata
and eventually
T. stellata
died off as fermentation progressed, leaving
S. cerevisiae
as the dominant yeast until the termination of fermentation by the addition of sulfur dioxide. At least two different strains of
S. cerevisiae
were involved in the fermentation of one of the red wines. Low levels of lactic acid bacteria (
Pediococcus cerevisiae, Leuconostoc mesenteroides
, and
Lactobacillus
spp.) were present in grape musts but died off during alcoholic fermentation. The malolactic fermentation developed in both red wines soon after alcoholic fermentation and correlated with the vigorous growth of at least three different strains of
Leuconostoc oenos.
Phosphonate Utilization by the Glyphosate-Degrading
Pseudomonas
sp. Strain PG2982
Authors: Shinabarger Dean L. , Schmitt Eric K. , Braymer Hugh D. , Larson Alworth D.
Published: January 2020

The glyphosate-degrading
Pseudomonas
sp. strain PG2982 was found to utilize each of 10 organophosphonate compounds as a sole phosphorus source. Representative compounds tested included alkylphosphonates, 1-amino-substituted alkylphosphonates, amino-terminal phosphonates, and an arylphosphonate. This report demonstrates that PG2982 is capable of utilizing a wider range of structurally different organophosphonate compounds than any organism described to date.
Recreational water quality analyses of the Colorado River corridor in Grand Canyon
Authors: Tunnicliff B , Brickler S K
Published: January 2020

We intensively examined the recreational water quality of the Colorado River and 26 tributaries in Grand Canyon National Park over four consecutive summers. Highly ephemeral precipitation cycles and arid watershed hydrologies were the principal factors influencing water quality. Fecal coliforms (FC) in the river and in most tributaries were less than or equal to 10 FC 100 ml-1 and less than or equal to 20 FC 100 ml-1, respectively, during drought cycles. During rainfall cycles, FC densities were highly variable and often exceeded recreational contact standards. FC were not found to vary significantly in response to diurnal fluctuations in river stage height which resulted from hydroelectric stream flow regulation. River and tributary bottom sediments harbored FC in densities averaging 10 to 100 times those in the overlying waters. Sediment FC densities were not found to be reliable indicators of overlying water quality when storm flow and nonstorm flow periods were compared.
Effects of antimetabolites on the adhesion of an estuarine Vibrio sp. to polystyrene
Authors: Paul J H
Published: January 2020

The effect of various metabolic inhibitors and antibiotics on the adhesion of an estuarine bacterium, Vibrio proteolytica, to polystyrene was investigated. Cells were either exposed to the substratum and the antimetabolite simultaneously or grown in the presence of a 25% MIC and presented the substratum in the absence of the antimetabolite. Based on the response elicited, these inhibitors could be divided into three classes: (i) those that had little or no effect on adhesion (fluorodeoxyuridine and nalidixic acid); (ii) those that only inhibited adhesion after growth at the 25% MIC (ampicillin, oxacillin, and streptomycin); and (iii) those that inhibited attachment when administered simultaneously with the substratum (azide, dinitrophenol, chloramphenicol, puromycin, azauridine, rifampin, p-chloromercuribenzoate, and cephalothin). Cells killed by heating, Formalin, or mercuric chloride treatment were also less adhesive than viable cells. Collectively, these results indicate that (i) physiologically active cells are more adhesive than dead or physiologically impaired cells, (ii) impairment of cell wall synthesis by beta-lactam antibiotics renders cells less adhesive, and (iii) energy production and protein synthesis (including transcription) are both involved in some aspect of the adhesion process, whereas DNA synthesis is not.
Comparison of
p
-Nitrophenol Biodegradation in Field and Laboratory Test Systems
Authors: Spain J. C. , Van Veld P. A. , Monti C. A. , Pritchard P. H. , Cripe C. R.
Published: January 2020

Acclimation of microbial communities exposed to
p
-nitrophenol (PNP) was measured in laboratory test systems and in a freshwater pond. Laboratory tests were conducted in shake flasks with water, shake flasks with water and sediment, eco-cores, and two sizes of microcosm. The sediment and water samples used in the laboratory experiments were obtained from the pond. After a 6-day acclimation period, PNP was biodegraded rapidly in the pond. When the pond was treated with PNP a second time, biodegradation began immediately. The acclimation periods in laboratory test systems that contained sediment were similar to that in the pond. The acclimation period was threefold longer in shake flasks without sediment. PNP was biodegraded more slowly by microbial communities acclimated in the laboratory than it was in the pond, and the rate of biodegradation varied with the type of test. The number of bacteria able to mineralize PNP increased by 3 orders of magnitude in the pond during the acclimation period. Similar increases accompanied acclimation in the laboratory systems.
Characterization of predominant bacteria from the colons of normal and dysenteric pigs
Authors: Robinson I M , Whipp S C , Bucklin J A , Allison M J
Published: January 2020

Bacterial populations adherent to the mucosa of the proximal colons of weaned, healthy pigs were compared with populations from pigs with dysentery induced by inoculation with a culture of Treponema hyodysenteriae. Isolates (136) representative of the predominant flora adherent to colonic epithelia of normal pigs and isolates (162) from pigs with dysentery were cultured anaerobically on a rumen fluid-based medium and characterized. Most (71%) of the isolates from colonic epithelia of normal pigs were gram positive, whereas 88% of the epithelia-associated isolates from pigs with dysentery were gram negative. The geometric mean of colony counts was 5.7 X 10(7)/cm2 of colonic tissue from three normal pigs and 7.7 X 10(8)/cm2 from four pigs with dysentery. A number of isolates obtained from contents of the lumens of normal pigs with dysentery were also characterized. Comparison of isolates from epithelial tissue and from contents of the lumens of the same pig indicated that these populations were different. Our results indicate that physiological changes that occur in the colons of pigs with dysentery are accompanied by marked changes in the microbial populations in the colons. The factors which regulate the population changes are not yet understood.
Sensitivity of Legionella pneumophila to sunlight in fresh and marine waters
Authors: Dutka B J
Published: January 2020

Studies were carried out to assess the sunlight sensitivity of Legionella pneumophila suspended in fresh and marine waters. Comparison studies on sunlight sensitivity of lake water bacteria, Pseudomonas aeruginosa, Escherichia coli and Streptococcus faecalis, were also undertaken. The effects of full sunlight and polyacrylic-screened sunlight were monitored in the study. Results indicate that L. pneumophila cells are slightly more sensitive to sunlight in seawater than in fresh water. Enumeration of sunlight-stressed bacteria in fresh water was found to be dependent on the medium used, and the following order of sensitivity to sunlight, from least to most sensitive, was noted: natural lake water bacteria, L. pneumophila, P. aeruginosa, E. coli, and S. faecalis.
Germination of
Rhizopus oligosporus
Sporangiospores
Authors: Medwid Richard D. , Grant Dale W.
Published: January 2020

The morphology of
Rhizopus oligosporus
(NRRL 2710) sporangiospores and their physiological requirements for germination were studied. Germination proceeded in two separable phases: phase I (swelling) and phase II (germ tube protrusion). The optimal conditions for germination were 42�C and pH 4.0. Sporangiospores contained insufficient endogenous carbon for swelling or germination to occur in distilled water. Initial swelling during phase I occurred only in the presence of a suitable carbohydrate. Subsequent production of germ tubes during phase II required exogenous sources of both carbon and nitrogen. Spores germinated most rapidly in mixtures of amino acids;
l
-proline and
l
-alanine were the most effective. These amino acids, at concentrations as low as 10
−6
M, supported germination when combined with glucose and McIlvaine (citric acid-phosphate) buffer.
d
-Glucose,
d
-xylose, and
d
-mannose were the most effective carbohydrates tested for promotion of germination.
Alternative pathways for biosynthesis of leucine and other amino acids in Bacteroides ruminicola and Bacteroides fragilis
Authors: Allison M J , Baetz A L , Wiegel J
Published: January 2020

Bacteroides ruminicola is one of several species of anaerobes that are able to reductively carboxylate isovalerate (or isovaleryl-coenzyme A) to synthesize alpha-ketoisocaproate and thus leucine. When isovalerate was not supplied to growing B. ruminicola cultures, carbon from [U-14C]glucose was used for the synthesis of leucine and other cellular amino acids. When unlabeled isovalerate was available, however, utilization of [U-14C]glucose or [2-14C]acetate for leucine synthesis was markedly and specifically reduced. Enzyme assays indicated that the key enzyme of the common isopropylmalate (IPM) pathway for leucine biosynthesis, IPM synthase, was present in B. ruminicola cell extracts. The specific activity of IPM synthase was reduced when leucine was added to the growth medium but was increased by the addition of isoleucine plus valine, whereas the addition of isovalerate had little or no effect. The activity of B. ruminicola IPM synthase was strongly inhibited by leucine, the end product of the pathway. It seems unlikely that the moderate inhibition of the enzyme by isovalerate adequately explains the regulation of carbon flow by isovalerate in growing cultures. Bacteroides fragilis apparently also uses either the isovalerate carboxylation or the IPM pathway for leucine biosynthesis. Furthermore, both of these organisms synthesize isoleucine and phenylalanine, using carbon from 2-methylbutyrate and phenylacetate, respectively, in preference to synthesis of these amino acids de novo from glucose. Thus, it appears that these organisms have the ability to regulate alternative pathways for the biosynthesis of certain amino acids and that pathways involving reductive carboxylations are likely to be favored in their natural habitats.
Production of Solvents by
Clostridium acetobutylicum
Cultures Maintained at Neutral pH
Authors: Holt Robert A. , Stephens Gillian M. , Morris J. Gareth
Published: January 2020

The formation of acetone and
n
-butanol by
Clostridium acetobutylicum
NCIB 8052 (ATCC 824) was monitored in batch culture at 35�C in a glucose (2% [wt/vol]) minimal medium maintained throughout at either pH 5.0 or 7.0. At pH 5, good solvent production was obtained in the unsupplemented medium, although addition of acetate plus butyrate (10 mM each) caused solvent production to be initiated at a lower biomass concentration. At pH 7, although a purely acidogenic fermentation was maintained in the unsupplemented medium, low concentrations of acetone and
n
-butanol were produced when the glucose content of the medium was increased (to 4% [wt/vol]). Substantial solvent concentrations were, however, obtained at pH 7 in the 2% glucose medium supplemented with high concentrations of acetate plus butyrate (100 mM each, supplied as their potassium salts). Thus,
C. acetobutylicum
NCIB 8052, like
C. beijerinckii
VPI 13436, is able to produce solvents at neutral pH, although good yields are obtained only when adequately high concentrations of acetate and butyrate are supplied. Supplementation of the glucose minimal medium with propionate (20 mM) at pH 5 led to the production of some
n
-propanol as well as acetone and
n
-butanol; the final culture medium was virtually acid free. At pH 7, supplementation with propionate (150 mM) again led to the formation of
n
-propanol but also provoked production of some acetone and
n
-butanol, although in considerably smaller amounts than were obtained when the same basal medium had been fortified with acetate and butyrate at pH 7.
Ochratoxin A-induced teratogenesis in rats: partial protection by phenylalanine
Authors: Mayura K , Parker R , Berndt W O , Phillips T D
Published: January 2020

Ochratoxin A (OA), an important foodborne mycotoxin, is a potent teratogenic and nephrotoxic agent produced by several species of Aspergillus and Penicillium. OA is a known inhibitor of protein synthesis via competition with phenylalanine (Phe) in the phenylalanyl-tRNA synthetase-catalyzed reaction. It also has been reported that a variety of toxic effects of OA can be prevented by Phe. This study was designed to determine whether Phe could prevent or diminish the teratogenic effects of OA in rats. Pregnant Sprague-Dawley rats were injected with a single individual dose of OA (1.75 mg/kg) alone or in combination with a single dose of Phe (20 mg/kg) or in combination with either a single or daily dose of Phe (25 mg/kg). OA dissolved in 5% sodium bicarbonate and Phe dissolved in normal saline were administered subcutaneously on gestation day 7 to rats. The incidences of OA-induced fetal malformations (gross and skeletal) were significantly diminished in the presence of added Phe. These results indicate that coadministered Phe provides partial prenatal protection from the teratogenic effects of OA.
Characterization of Limulus amoebocyte lysate-reactive material from hollow-fiber dialyzers
Authors: Pearson F C , Bohon J , Lee W , Bruszer G , Sagona M , Jakubowski G , Dawe R , Morrison D , Dinarello C
Published: January 2020

Hollow-fiber hemodialyzers containing cellulose-based membranes have been shown to produce positive results with the Limulus amoebocyte lysate test. This study was undertaken to determine whether endotoxin was causing the reaction. Rinses from 45 parallel-plate and hollow-fiber dialyzers from eight different manufacturers were tested before and after treatment with cellulase, using three lysates and four Limulus amoebocyte lysate methods. In addition, four in vitro cellular methods--human leukocytic pyrogen, lymphocytic activating factor, peritoneal macrophage, and arginase release--were used to evaluate endotoxin activity. The substance causing the reaction was identified by chromatographic methods. Results indicate that the Limulus amoebocyte lysate reactive material is cellulose derived and not pyrogenic.
Isolate 761M: a New Type I Methanotroph That Possesses a Complete Tricarboxylic Acid Cycle
Authors: Zhao Shu-Jie , Hanson R. S.
Published: January 2020

A methanotrophic bacterium, isolate 761M, grows slowly with methane as the sole carbon and energy source. Growth was stimulated by peptone, casein hydrolysate, glucose, and acetate plus malate. Sugars other than glucose did not stimulate growth. Growth yields, based on the amount of methane consumed, increased when other carbon sources were present, and less methane carbon was assimilated under these conditions. Methane was obligately required for growth of isolate 761M. This bacterium does not grow on rich media. Isolate 761M was found to possess hexulose phosphate synthase and intracytoplasmic membranes characteristic of other type I methanotrophs. Unlike other type I methanotrophs, this bacterium possessed alpha-ketoglutarate dehydrogenase and oxidized [2-
14
C]acetate to carbon dioxide.
Protoplast Regeneration in
Clostridium tertium
: Isolation of Derivatives with High-Frequency Regeneration
Authors: Knowlton Susan , Ferchak John D. , Alexander James K.
Published: January 2020

A procedure was developed for the formation and regeneration of protoplasts in
Clostridium tertium
. Although in the parent strain most of the protoplasts gave rise to L-form colonies, derivatives could be isolated which exhibited high regeneration frequencies.
Comparison of enrichment methods and atmosphere modification procedures for isolating Campylobacter jejuni from foods
Authors: Heisick J , Lanier J , Peeler J T
Published: January 2020

A comparison was made of enrichment broths for recovery of Campylobacter jejuni from food by the methods of Doyle and Roman (Appl. Environ. Microbiol. 43:1343-1353) and of Park et al. (Can. J. Microbiol. 27:841-842). No significant differences were found between the results obtained with the two broths. Recovery was greater, however, with a constant gas flow into the broths than with an evacuation-replacement method.
A new medium for the enumeration and subculture of bacteria from potable water
Authors: Reasoner D J , Geldreich E E
Published: January 2020

Plate count agar is presently the recommended medium for the standard bacterial plate count (35 degrees C, 48-h incubation) of water and wastewater. However, plate count agar does not permit the growth of many bacteria that may be present in treated potable water supplies. A new medium was developed for use in heterotrophic plate count analyses and for subculture of bacteria isolated from potable water samples. The new medium, designated R2A, contains 0.5 g of yeast extract, 0.5 g of Difco Proteose Peptone no. 3 (Difco Laboratories), 0.5 g of Casamino Acids (Difco), 0.5 g of glucose, 0.5 g of soluble starch, 0.3 g of K2HPO4, 0.05 g of MgSO4 X 7H2O, 0.3 g of sodium pyruvate, and 15 g of agar per liter of laboratory quality water. Adjust the pH to 7.2 with crystalline K2HPO4 or KH2PO4 and sterilize at 121 degrees C for 15 min. Results from parallel studies with spread, membrane filter, and pour plate procedures showed that R2A medium yielded significantly higher bacterial counts than did plate count agar. Studies of the effect of incubation temperature showed that the magnitude of the count was inversely proportional to the incubation temperature. Longer incubation time, up to 14 days, yielded higher counts and increased detection of pigmented bacteria. Maximal bacterial counts were obtained after incubation at 20 degrees C for 14 days. As a tool to monitor heterotrophic bacterial populations in water treatment processes and in treated distribution water, R2A spread or membrane filter plates incubated at 28 degrees C for 5 to 7 days is recommended.(ABSTRACT TRUNCATED AT 250 WORDS)
Streptococcus-Escherichia coli shuttle vector pSA3 and its use in the cloning of streptococcal genes
Authors: Dao M L , Ferretti J J
Published: January 2020

A shuttle vector that can replicate in both Streptococcus spp. and Escherichia coli has been constructed by joining the E. coli plasmid pACYC184 (chloramphenicol and tetracycline resistance) to the streptococcal plasmid pGB305 (erythromycin resistance). The resulting chimeric plasmid is designated pSA3 (chloramphenicol, erythromycin, and tetracycline resistance) and has seven unique restriction sites: EcoRI, EcoRV, BamHI, SalI, XbaI, NruI, and SphI. Molecular cloning into the EcoRI or EcoRV site results in inactivation of chloramphenicol resistance, and cloning into the BamHI, SalI, or SphI site results in inactivation of tetracycline resistance in E. coli. pSA3 was transformed and was stable in Streptococcus sanguis and Streptococcus mutans in the presence of erythromycin. We have used pSA3 to construct a library of the S. mutans GS5 genome in E. coli, and expression of surface antigens in this heterologous host has been confirmed with S. mutans antiserum. A previously cloned determinant that specifies streptokinase was subcloned into pSA3, and this recombinant plasmid was stable in the presence of a selective pressure and expressed streptokinase activity in E. coli, S. sanguis (Challis), and S. mutans.
Effectiveness of
Rhizobium
Strains Used in Inoculants after Their Introduction into Soil
Authors: van Rensburg Henri Jansen , Strijdom Barend W.
Published: January 2020

Rhizobium
strains used in inoculants for
Trifolium
spp.,
Medicago
spp.,
Glycine max
, and
Lotus pedunculatus
were isolated from nodules of these legumes grown in soils into which the rhizobia had been introduced 4 to 8 years before. Isolations were made from a total of 420 nodules. Nodule occupancy by the inoculant strains varied from 17.7% for a soybean strain to 100% in the case of
L. pedunculatus
whose specific rhizobia did not occur in the soils studied. In general, inoculant strains isolated from nodules did not differ in effectiveness from cultures of the same strains concurrently maintained in lyophilized form. The average effectiveness of all of the isolates (identified and unidentified) from a legume was 7.1 to 73.3% higher than that of the unidentified isolates alone, demonstrating the prolonged effect that a single-seed inoculation has on the rhizobial population in a soil which had not been planted with legumes before. Relatively weak recovery of a
Rhizobium japonicum
strain introduced into soil 4 years after soybean seed inoculated with a different strain had been planted in the same soil confirmed the advantage of a resident population over an introduced inoculant strain.
Seasonal distribution of Vibrio parahaemolyticus in freshwater environs and in association with freshwater fishes in Calcutta
Authors: Sarkar B L , Nair G B , Banerjee A K , Pal S C
Published: January 2020

The seasonal distribution of Vibrio parahaemolyticus in freshwater environs and in association with freshwater fishes was studied in 1982 and 1983. The occurrence of this organism in water and sediments at the three sites studied was very infrequent and was restricted to the summer months, although it was not always isolated during these months. The association of V. parahaemolyticus with plankton was chiefly confined to the summer months and progressively declined with the onset of monsoons, remaining below detectable levels during the postmonsoon and winter months. The incidence and counts of V. parahaemolyticus were consistently higher in association with plankton than with water and sediment samples. V. parahaemolyticus could be recovered throughout the period of investigation from freshly caught and market samples of freshwater fishes. The highest recovery rate of this halophile from fishes was invariably from fecal samples. Most of the strains isolated in this study were untypable, and those which could be typed were predominantly serotypes encountered in the environment. All the isolates were Kanagawa negative. From this study, it could be concluded that the survival of V. parahaemolyticus in freshwater ecosystems is transient and dependent on a biological host.
Sulfate Reduction in Freshwater Sediments Receiving Acid Mine Drainage
Authors: Herlihy Alan T. , Mills Aaron L.
Published: January 2020

One arm of Lake Anna, Va., receives acid mine drainage (AMD) from Contrary Creek (SO
4
2−
concentration = 2 to 20 mM, pH = 2.5 to 3.5). Acid-volatile sulfide concentrations, SO
4
2−
reduction rates, and interstitial SO
4
2−
concentrations were measured at various depths in the sediment at four stations in four seasons to assess the effects of the AMD-added SO
4
2−
on bacterial SO
4
2−
reduction. Acid-volatile sulfide concentrations were always an order of magnitude higher at the stations receiving AMD than at a control station in another arm of the lake that received no AMD. Summer SO
4
2−
reduction rates were also an order of magnitude higher at stations that received AMD than at the control station (226 versus 13.5 mmol m
−2
day
−1
), but winter values were inconclusive, probably due to low sediment temperature (6°C). Profiles of interstitial SO
4
2−
concentrations at the AMD stations showed a rapid decrease with depth (from 1,270 to 6 μM in the top 6 cm) due to rapid SO
4
2−
reduction. Bottom-water SO
4
2−
concentrations in the AMD-receiving arm were highest in winter and lowest in summer. These data support the conclusion that there is a significant enhancement of SO
4
2−
reduction in sediments receiving high SO
4
2−
inputs from AMD.
Minimum bacterial density for bacteriophage replication: implications for significance of bacteriophages in natural ecosystems
Authors: Wiggins B A , Alexander M
Published: January 2020

Bacteriophage 80 alpha did not increase in number in cultures containing less than about 1.0 X 10(4) to 1.5 X 10(4) CFU of Staphylococcus aureus per ml, but bacteriophage replication did occur when the number of bacteria exceeded this density, either initially or as a result of host cell multiplication. The minimum density of an asporogenous strain of Bacillus subtilis required for an increase in the number of bacteriophage SP beta cI was about 3 X 10(4) CFU/ml. The threshold density of Escherichia coli for the multiplication of bacteriophage T4 was about 7 X 10(3) CFU/ml. In the presence of montmorillonite, bacteriophage T4 did not increase in number until the E. coli population exceeded 10(4) CFU/ml. The mineralization of glucose was not affected in E. coli cultures inoculated with a low number of bacteriophage T4, but it could not be detected in cultures inoculated with a large number of phage. The numbers of bacteriophage T4 and a bacteriophage that lyses Pseudomonas putida declined rapidly after being added to lake water or sewage. We suggest that bacteriophages do not affect the number or activity of bacteria in environments where the density of the host species is below the host cell threshold of about 10(4) CFU/ml.
A temperate phage of Streptomyces azureus
Authors: Ogata S , Suenaga H , Hayashida S
Published: January 2020

A new phage, SAt1, was isolated from soil on Streptomyces azureus ATCC 14921. This phage was able to lysogenize S. azureus. The percentage of lysogenic responses was ca. 10%. Electron microscopic observation showed that this phage belonged to group B of Bradley's morphological classification. The molecular mass of SAt1 DNA was ca. 24 megadaltons. The guanine-plus-cytosine content and the density of SAt1 DNA were ca. 71% and 1.724 g/cm3, respectively. A cleavage map of SAt1 DNA was constructed with restriction endonucleases BanIII, BglII, HindIII, and XbaI. Furthermore, some other characteristics of this phage were investigated.
Gas chromatographic assay for in vitro complementation of Pseudomonas aeruginosa mutants deficient in nitrate reduction
Authors: Hernandez D , Rowe J J
Published: January 2020

An electron capture gas-chromatographic technique was developed to continuously measure nitrate (NO3-) reduction during in vitro complementation tests with extracts from Pseudomonas aeruginosa mutants deficient in both assimilatory and dissimilatory nitrate reduction as a result of a single genetic mutation. The procedure involves coupling nitrate reduction to nitrous oxide (N2O) evolution via a series of reactions specific to the denitrification pathway. The assay was dependent on nitrate concentration, and optimal activity was obtained with a final concentration of 0.2% potassium nitrate. The reduction exhibited a stoichiometry of 2:1 (NO3-/N2O), and succinate was the best electron source for the reaction, followed by glucose, pyruvate, and malate. The technique can also be used for continuously monitoring nitrate reduction. The optimal nitrite concentration in the nitrite reductase assay was 0.025%. The initial complementation studies of mutant extracts demonstrated that at least two genes are shared between the two nitrate reduction pathways in P. aeruginosa.
Incidence of Acinetobacter spp. and other gram-negative, oxidase-negative bacteria in fresh and spoiled ground beef
Authors: Eribo B E , Jay J M
Published: January 2020

A total of 1,409 gram-negative bacterial colonies were randomly selected from 19 samples of fresh and spoiled ground beef plated on six media. Only 137 (9.7%) were oxidase negative, and 20 (14.6%) of these were Acinetobacter spp., all of which were recovered from fresh meat samples. The importance of this group in both fresh and spoiled beef is less than is generally believed.
New Selective Media for Enumeration and Recovery of Fluorescent Pseudomonads from Various Habitats
Authors: Gould W. D. , Hagedorn C. , Bardinelli T. R. , Zablotowicz R. M.
Published: January 2020

New media (S1 and S2) were formulated that provide a high degree of selectivity and detection of fluorescent pseudomonads on initial plating. The selectivity of the S-type media was based on a detergent, sodium lauroyl sarcosine, and an antibiotic, trimethoprim. A total of five soils from different geographical locations and one sewage sludge sample were examined. On S1 medium, isolates from two soils with low fluorescent pseudomonad populations exhibited a high frequency of arginine dihydrolase (78%) and oxidase-positive (95%) phenotypes, but no fermentative isolates were recovered. Medium S2 was more defined and selective than S1, but lower numbers of fluorescent pseudomonads were recovered on S2. In soils in which fluorescent pseudomonads represent a small proportion of the total population, S1 medium consistently recovered high percentages of fluorescent phenotypes (82.5%).
Comparison of selective media for assay of coliphages in sewage effluent and lake water
Authors: Kennedy J E , Bitton G , Oblinger J L
Published: January 2020

Selective media, including EC medium, gram-negative broth, nutrient broth (with 0.05% sodium deoxycholate), and lactose broth (with 0.05% sodium deoxycholate), as well as nonselective nutrient and lactose broths, were compared for the enumeration of coliphages by the agar layer method from activated-sludge effluent and eutrophic-lake water from a lake receiving treated sewage effluent. Samples were plated directly or after chloroform treatment with Escherichia coli B, E. coli C, or a mixed host of both E. coli B and C. With the exception of gram-negative broth, direct assays of all samples with the selective media generally resulted in significantly higher (P less than 0.05) recoveries of coliphages than did assays of chloroform-treated samples with nutrient broth medium regardless of the host used. In addition, chloroform pretreatment resulted in decreased recovery of coliphages with each selective medium in most analyses. The highest recoveries of coliphages from all samples with each host, except lake water with E. coli C, were obtained by direct assay on EC medium. The selectivity of the EC and gram-negative media resulted in suppression of bacterial interference on direct assay plates comparable to that observed in nutrient agar medium with chloroform-treated samples. The use of certain selective media for the direct assay of environmental materials for coliphage may enhance the recovery of coliphages and obviate bacterial decontamination procedures.