bluuebunny/crossref_metadata_2025 huggingface dataset:
Antibiotic Y: biosynthesis by Fusarium avenaceum (Corda ex Fries) Sacc., isolation, and some physicochemical and biological properties
Authors: Goliński P , Wnuk S , Chełkowski J , Visconti A , Schollenberger M
Published: January 2020

A compound very similar to the mycotoxin citrinin was observed on thin-layer chromatographic plates during the screening analysis of grain extracts. This compound was produced by 22 of the tested Fusarium avenaceum (Corda ex Fries) Sacc. strains isolated from wheat, triticale, barley, corn, and potatoes. A chemical test confirmed the presence of an unknown compound, which was given the preliminary name of antibiotic Y (indicating yellow fluorescence). The following properties of the new metabolite are described: spectroscopic (UV, infrared, proton nuclear magnetic resonance, fluorescence, and mass spectrometry), phytotoxic, antibiotic (inhibitory effect of bacterial growth), and toxic (toxicity to Artemia salina, chicken embryos, and mouse fibroblasts). Elemental analysis of the compound showed that it had the general formula C15H10O8, in agreement with the mass spectrometric finding that the molecular ion had a molecular weight of 318. The structure of the compound is presently under study.
Radioisotopic Method for Measuring Cell Division Rates of Individual Species of Diatoms from Natural Populations
Authors: Rivkin Richard B.
Published: January 2020

Silicon is an essential element for diatom frustule synthesis and is usually taken up only by dividing cells. With
68
Ge, a radioactive analog of Si, the cell cycle marker event of frustule formation was identified for individual species of diatom. The frequency of cells within a population undergoing this division event was estimated, and the cell division rate was calculated. In laboratory cultures, these rates of cell division and those calculated from changes in cell numbers were similar. By dual labeling with
68
Ge(OH)
4
and NaH
14
CO
3
, rates of cell division and photosynthesis were coincidently measured for diatoms both in laboratory cultures and when isolated from natural populations in estuarine, offshore, and polar environments. These techniques permit the coupling between photosynthesis and cell division to be examined in situ for individual species of diatom.
Removal of endotoxin from water by microfiltration through a microporous polyethylene hollow-fiber membrane
Authors: Sawada Y , Fujii R , Igami I , Kawai A , Kamiki T , Niwa M
Published: January 2020

The microporous polyethylene hollow-fiber membrane has a unique microfibrile structure throughout its depth and has been found to possess the functions of filtration and adsorption of endotoxin in water. The membrane has a maximum pore diameter of approximately 0.04 micron, a diameter which is within the range of microfiltration. Approximately 10 and 20% of the endotoxin in tap water and subterranean water, respectively, was smaller than 0.025 micron. Endotoxin in these water sources was efficiently removed by the microporous polyethylene hollow-fiber membrane. Escherichia coli O113 culture broth contained 26.4% of endotoxin smaller than 0.025 micron which was also removed. Endotoxin was leaked into the filtrate only when endotoxin samples were successively passed through the membrane. These results indicate that endotoxin smaller than the pore size of the membrane was adsorbed and then leaked into the filtrate because of a reduction in binding sites. Dissociation of 3H-labeled endotoxin from the membrane was performed, resulting in the removal of endotoxin associated with the membrane by alcoholic alkali at 78% efficiency.
Nitrogen Fixation Associated with Development and Localization of Mixed Populations of
Cellulomonas
sp. and
Azospirillum brasilense
Grown on Cellulose or Wheat Straw
Authors: Halsall Dorothy M. , Goodchild David J.
Published: January 2020

Mixed cultures of
Cellulomonas
sp. and
Azospirillum brasilense
were grown with straw or cellulose as the carbon source under conditions favoring the fixation of atmospheric nitrogen. Rapid increases in cell numbers, up to 10
9
cells per g of substrate, were evident after 4 and 5 days of incubation at 30°C for cellulose and straw, respectively. Nitrogen fixation (detected by acetylene reduction measured on parallel cultures) commenced after 2 and 4 days of incubation for straw and cellulose, respectively, and continued for the duration of the experiment. Pure cultures of
Cellulomonas
sp. showed an increase in cell numbers, but CO
2
production was low, and acetylene reduction was not detected on either cellulose or straw. Pure cultures of
A. brasilense
on cellulose showed an initial increase in cell numbers (10
7
cells per g of substrate) over 4 days, followed by a decline presumably caused by the exhaustion of available carbon substrate. On straw,
A. brasilense
increased to 10
9
cells per g of substrate over 5 days and then declined slowly; this growth was accompanied by acetylene reduction. Scanning electron micrographs of straw incubated with a mixed culture under the above conditions for 8 days showed cells of both species in close proximity to each other. Evidence was furnished that the close spatial relationship of cells from the two species facilitated the mutually beneficial association between them and thus increased the efficiency with which the products of straw breakdown were used for nitrogen fixation.
Kinetics of mineralization of organic compounds at low concentrations in soil
Authors: Scow K M , Simkins S , Alexander M
Published: January 2020

The kinetics of mineralization of 14C-labeled phenol and aniline were measured at initial concentrations ranging from 0.32 to 5,000 ng and 0.30 ng to 500 micrograms/g of soil, respectively. Mineralization of phenol at concentrations less than or equal to 32 ng/g of soil and of aniline at all concentrations began immediately, and the curves for the evolution of labeled CO2 were biphasic. The patterns of mineralization of 4.0 ng of 2,4-dichlorophenol per g of soil and 20 ng of nitrilotriacetic acid per g of soil were similar to the patterns for phenol and aniline. The patterns of mineralization of 1.0 to 100 ng of p-nitrophenol and 6.0 ng of benzylamine per g of soil were also biphasic but after a short apparent lag period. The curves of CO2 evolution from higher concentrations of phenol and p-nitrophenol had increasing apparent lag phases and were S-shaped or linear. Cumulative plots of the percentage of substrate converted to CO2 were fit by nonlinear regression to first-order, integrated Monod, logistic, logarithmic, zero-order, three-half-order, and two-compartment models. None of the models of the Monod family provided the curve of best fit to any of the patterns of mineralization. The linear growth form of the three-half-order model provided the best fit for the mineralization of p-nitrophenol, with the exception of the lowest concentrations, and of benzylamine. The two-compartment model provided the best fit for the mineralization of concentrations of phenol below 100 ng/g, of several concentrations of aniline, and of nitrilotriacetic acid. It is concluded that models derived from the Monod equation, including the first-order model, do not adequately describe the kinetics of mineralization of low concentrations of chemicals added to soil.
Bioaccumulation of Germanium by
Pseudomonas putida
in the Presence of Two Selected Substrates
Authors: Chmielowski Jerzy , Kłapcińska Barbara
Published: January 2020

The uptake of germanium by
Pseudomonas putida
ATCC 33015 was studied in the presence of catechol or acetate or both as representative substrates differing in their ability to form complexes with this element. The bacteria were taken from a batch culture grown on acetate as the sole carbon source. Cells introduced into a medium containing germanium and either catechol or a mixture of catechol and acetate accumulated germanium in a biphasic way. After a lower level of accumulation that corresponded to the value obtained in the presence of acetate was reached, a further increase in the germanium content up to a higher saturation level was observed. The appearance of the second step of accumulation, which corresponded to the linear degradation of catechol, proved that catechol facilitated the transport of germanium into the cells through the nonspecific uptake of the germanium-catechol complex by an inducible catechol transport system.
A simple and generally applicable procedure for releasing DNA from bacterial cells
Authors: Heath L S , Sloan G L , Heath H E
Published: January 2020

Treatment of Staphylococcus simulans biovar staphylolyticus cells with acetone before digestion with lysozyme made the cells susceptible to lysis by sodium dodecyl sulfate. This technique was found to be useful for releasing DNA from a wide variety of gram-positive and gram-negative organisms.
Kinetics of mineralization of phenols in lake water
Authors: Jones S H , Alexander M
Published: January 2020

The kinetics of mineralization of phenol and p-nitrophenol in lake water was determined at concentrations from 200 pg/ml to 5 micrograms/ml. The mineralization data were fit by nonlinear regression to equations for 14 kinetic models that describe patterns of biodegradation by nongrowing cells or by microorganisms growing on either the test chemical or other organic substrates. The kinetics od mineralization of phenol in water samples collected in July was best described by first-order models for 0.5 ng of phenol per ml; by Monod-without-growth, logistic, and logarithmic models for 1.0 and 2.0 ng/ml and 5.0 ng/ml to 1.0 micrograms/ml, respectively, if it is assumed that the mineralizing population uses phenol as the sole carbon source for growth; by models (for phenol at concentrations of 2.0 ng/ml to 1.0 micrograms/ml) that assume that the phenol-mineralizing populations do not grow or grow logarithmically or logistically on uncharacterized carbon compounds but metabolize the phenol when present at levels below and above Km, respectively, for that compound; and by a logarithmic model at 5.0 micrograms/ml. Under the test conditions, usually less than 10% of the phenol C that was metabolized was incorporated into microbial cells or retained by other particulate material in the water at substrate concentrations of 10 ng/ml or less, and the percentage increased at higher substrate concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
Trichothecenes produced by Stachybotrys atra from Eastern Europe
Authors: Jarvis B B , Lee Y W , Cömezoglu S N , Yatawara C S
Published: January 2020

A total of 17 isolates of Stachybotrys atra isolated from various parts of Hungary and Czechoslovakia were grown on rice, and the toxin production of each isolate was analyzed by high-performance liquid chromatography. Of the 17 isolates, 14 produced macrocyclic trichothecenes (satratoxins F, G, and H, roridin E, and verrucarin J) as well as trichoverrols A and B. Most isolates produced satratoxins G and H in higher quantities than the other trichothecenes. The yield (in milligrams) of trichothecenes produced by one isolate grown on 800 g of rice was as follows: roridin E, 12; satratoxin F, 10; satratoxin G, 75; satratoxin H, 100; trichoverrol A, 15; and trichoverrol B, 30.
Methodology for enumeration of coliphages in foods
Authors: Kennedy J E , Wei C I , Oblinger J L
Published: January 2020

The effects of eluent composition, pH, and chaotropic agents on the recovery of T2, MS2, and indigenous coliphages from various foods were investigated. Additionally, methods of sample suspension and clarification were evaluated for coliphage recovery and application to various foods. Clarified sample suspensions were assayed for coliphages with a modified agar layer technique and appropriate Escherichia coli hosts. Centrifugation and polypropylene mesh filtration were more rapid and effective than glass wool filtration for clarification of sample suspensions and subsequent recovery of coliphages. Blending, stomaching, and shaking procedures were generally comparable for sample liquefaction and release of coliphages from foods. Complex basal eluents, EC medium and 1% casein, were generally more effective than a less complex eluent, phosphate buffer, for elution of coliphages from foods. For most foods, incorporation of sodium chloride or chaotropic agents, i.e., sodium trichloroacetate, urea, Tween 80, Triton X-100, and sodium nitrate, into basal eluents did not enhance recovery of coliphages. Indigenous coliphage recovery was not affected by sample suspension pH over a range of 6.0 to 9.0. With an optimal procedure, i.e., EC medium eluent, blending, and centrifugation, the recovery of T2 and MS2 ranged from 48 to 81% and from 58 to 100%, respectively, depending on the food type.
Pattern recognition analysis of in vivo enzyme-substrate fluorescence velocities in microorganism detection and identification
Authors: Snyder A P , Wang T T , Greenberg D B
Published: January 2020

A spectrometric technique is presented that combines most of the important criteria necessary for efficient detection and identification of microorganisms. These criteria include simplicity of experimental design, various degrees of sensitivity and selectivity, convenience, and total reaction times of less than 15 min. The study takes advantage of the inherent extracellular enzymes present in living as opposed to dead, non-enzyme-producing organisms. Sequentially these are harnessed in in vivo reactions with a substrate containing a select organic functional group that is known to be cleaved or hydrolyzed by a certain enzyme. The substrate is tailored so that one of the products can be induced to fluoresce, and by using a conventional spectrofluorimeter the rate at which the fluorescence appears can be recorded. By subjecting the same bacterial sample to a number of different enzyme substrates, a pattern of fluorescence response rates emerges from a 7 by 7 microorganism-substrate matrix. Detection limits ranged from 3.6 X 10(2) to 3.5 X 10(8) cells per ml for the Bacillus globigii-indoxyl acetate and Escherichia coli-diacetylfluorescein pairs, respectively. The specificity and versatility of the method for bacterial determination is demonstrated in probing different bacterial enzymes through their spectrally active metabolic products.
Pilot plant production of rhamnolipid biosurfactant by Pseudomonas aeruginosa
Authors: Reiling H E , Thanei-Wyss U , Guerra-Santos L H , Hirt R , Käppeli O , Fiechter A
Published: January 2020

Rhamnolipid biosurfactants were continuously produced with Pseudomonas aeruginosa on the pilot plant scale. Production and downstream processing elaborated on the laboratory scale were adapted to the larger scale. Differences in performance resulting from the scale-up are discussed. A biosurfactant concentration of approximately 2.25 g liter-1 was achieved. The biosurfactant yield on glucose was 77 mg g-1 h-1, and the productivity was 147 mg liter-1 h-1, corresponding to a daily production of 80 g of biosurfactant. The first enrichment step consisted of an adsorption chromatography which was followed by an anion-exchange chromatography. The resulting product was 90% pure, and the overall recovery of active material was above 60% with the downstream processing used.
Inhibition of Yersinia enterocolitica serotype O3 by natural microflora of pork
Authors: Fukushima H , Gomyoda M
Published: January 2020

Yersinia enterocolitica serotype O3 did not grow but did survive in inoculated raw ground pork kept at 6 and 25 degrees C. The antagonistic effect of microbial flora, especially Hafnia alvei and environmental Yersinia organisms, on the growth of Y. enterocolitica serotype O3 in raw ground pork was evident. These results were supported by evidence of the inhibition of growth of Y. enterocolitica serotype O3 by Enterobacteriaceae, especially H. alvei and environmental Yersinia organisms, in mixed cultures at 6 and 25 degrees C. We suggest that naturally contaminated pork is a source of human infection, since Y. enterocolitica serotype O3 was capable of surviving in the raw pork for a long time.
Population Dynamics of
Chlamydomonas sajao
and Its Influence on Soil Aggregate Stabilization in the Field
Authors: Metting Blaine
Published: January 2020

Chlamydomonas sajao
, a single-celled, eucaryotic microalga, was inoculated onto replicated field plots cropped to corn at two rates (5 × 10
11
and 5 × 10
7
log-phase cells ha
−1
) to assess colonization, reproduction, and persistence, changes in soil carbohydrate content, and wet stability of 0.92- to 1.68-mm-sized aggregates from the surface 2- to 3-mm soil veneer. The most-probable-number technique and extraction and fluorometric quantification of chlorophyll were used as indices of microalgal abundance. Cell numbers ranged up to 6.9 × 10
6
g of soil
−1
by most probable number and were significantly greater on high-rate than on low-rate and control plots over a 10-week period. Chlorophyll content and most probable number were positively correlated (
r
= 0.64) for the high-rate plots but not for low-rate plots or the controls. Increased wet aggregate stability measurements (33 to 77%) for the high-rate plots during the growing season were significantly greater than for low-rate and control plots, which were not different from each other. The work leads support to the hypothesis that mass-cultured palmelloid microalgae are a feasible means for conditioning soil biologically.
A New Sulfur-Reducing, Extremely Thermophilic Eubacterium from a Submarine Thermal Vent
Authors: Belkin Shimshon , Wirsen Carl O. , Jannasch Holger W.
Published: January 2020

A newly described bacterial isolate, designated strain NS-E, differs from presently known extremely thermophilic bacteria in various characteristics. It is a strictly heterotrophic eubacterium of marine origin and has a temperature range for growth of 50 to 95°C with an optimum at 77°C and a pH of 7.5. Its DNA base composition is 41.3 mol% guanine + cytosine. It is obligately anaerobic, utilizes various sugars as well as yeast extract, and reduces elemental sulfur facultatively to hydrogen sulfide. In 24-h cultures cell densities are up to fourfold higher in the presence than in the absence of elemental sulfur. Sulfide concentrations of 1.0 and 10.0 mM limit growth by 65 and 95%, respectively. Oxygen sensitivity is apparent only at or above that range of temperature at which growth occurs.
Countermeasures to Microbiofouling in Simulated Ocean Thermal Energy Conversion Heat Exchangers with Surface and Deep Ocean Waters in Hawaii
Authors: Berger Leslie Ralph , Berger Joyce A.
Published: January 2020

Countermeasures to biofouling in simulated ocean thermal energy conversion heat exchangers have been studied in single-pass flow systems, using cold deep and warm surface ocean waters off the island of Hawaii. Manual brushing of the loops after free fouling periods removed most of the biofouling material. However, over a 2-year period a tenacious film formed. Daily free passage of sponge rubber balls through the tubing only removed the loose surface biofouling layer and was inadequate as a countermeasure in both titanium and aluminum alloy tubes. Chlorination at 0.05, 0.07, and 0.10 mg liter
-1
for 1 h day
-1
lowered biofouling rates. Only at 0.10 mg liter
-1
was chlorine adequate over a 1-year period to keep film formation and heat transfer resistance from rising above the maximum tolerated values. Lower chlorination regimens led to the buildup of uneven or patchy films which produced increased flow turbulence. The result was lower heat transfer resistance values which did not correlate with the amount of biofouling. Surfaces which were let foul and then treated with intermittent or continuous chlorination at 0.10 mg of chlorine or less per liter were only partially or unevenly cleaned, although heat transfer measurements did not indicate that fact. It took continuous chlorination at 0.25 mg liter
-1
to bring the heat transfer resistance to zero and eliminate the fouling layer. Biofouling in deep cold seawater was much slower than in the warm surface waters. Tubing in one stainless-steel loop had a barely detectable fouling layer after 1 year in flow. With aluminum alloys sufficient corrosion and biofouling material accumulated to require that some fouling coutermeasure be used in long-term operation of an ocean thermal energy conversion plant.
Automatic Determination of Bacterioplankton Biomass by Image Analysis
Authors: Bjørnsen Peter Koefoed
Published: January 2020

Image analysis was applied to epifluorescense microscopy of acridine orange-stained plankton samples. A program was developed for discrimination and binary segmentation of digitized video images, taken by an ultrasensitive video camera mounted on the microscope. Cell volumes were estimated from area and perimeter of the objects in the binary image. The program was tested on fluorescent latex beads of known diameters. Biovolumes measured by image analysis were compared with directly determined carbon biomasses in batch cultures of estuarine and freshwater bacterioplankton. This calibration revealed an empirical conversion factor from biovolume to biomass of 0.35 pg of C μm
−3
(± 0.03 95% confidence limit). The deviation of this value from the normally used conversion factors of 0.086 to 0.121 pg of C μm
−3
is discussed. The described system was capable of measuring 250 cells within 10 min, providing estimates of cell number, mean cell volume, and biovolume with a precision of 5%.
Isolation of Halotolerant, Thermotolerant, Facultative Polymer-Producing Bacteria and Characterization of the Exopolymer
Authors: Pfiffner S. M. , McInerney Michael J. , Jenneman Gary E. , Knapp Roy M.
Published: January 2020

Over 200 bacterial strains were selected for anaerobic growth at 50°C and extracellular polysaccharide production in a sucrose-mineral salts medium with NaNO
3
and up to 10% NaCl. The predominant cell type was an encapsulated gram-positive, motile, facultative sporeforming rod similar to
Bacillus
species. Strain SP018 grew and produced the polysaccharide on a variety of substrates at salinities up to 12% NaCl. Good polymer production only occurred anaerobically and was optimal between 4 and 10% NaCl. The ethanol-precipitated SP018 polymer was a charged heteropolysaccharide that contained glucose, mannose, arabinose, ribose, and low levels of allose and glucosamine. The SP018 polymer showed pseudoplastic behavior, was resistant to shearing, and had a higher viscosity at dilute concentrations and at elevated temperatures than xanthan gum. High-ionic-strength solutions reversibly decreased the viscosity of SP018 polymer solutions. The bacterium and the associated polymer have many properties that make them potentially useful for in situ microbially enhanced oil recovery processes.
Selective medium for isolation of Fusarium species and dematiaceous hyphomycetes from cereals
Authors: Andrews S , Pitt J I
Published: January 2020

A selective medium containing 2 micrograms of dichloran per ml, 200 micrograms of chloramphenicol per ml, and 1.5% bacteriological peptone was developed for the isolation of Fusarium species and dematiaceous hyphomycetes from cereals. The medium, designated DCPA, was shown to select against species of Aspergillus, Penicillium, Cladosporium, and mucoraceous fungi. DCPA was evaluated for use as an enumeration medium and compared satisfactorily with dichloran-rose bengal-chloramphenicol agar when both media were tested with a range of cereal samples. Fusarium species and dematiaceous hyphomycetes produced well-formed colonies with good conidial production on DCPA, permitting rapid identification of such isolates on this medium.
Properties of a
Clostridium thermocellum
Endoglucanase Produced in
Escherichia coli
Authors: Schwarz Wolfgang H. , Gräbnitz Folke , Staudenbauer Walter L.
Published: January 2020

A cellulase gene of
Clostridium thermocellum
was transferred to
Escherichia coli
by molecular cloning with bacteriophage lambda and plasmid vectors and shown to be indentical with the
celA
gene. The
celA
gene product was purified from extracts of plasmid-bearing
E. coli
cells by heat treatment and chromatography on DEAE-Trisacryl. It was characterized as a thermophilic endo-β-1,4-glucanase, the properties of which closely resemble those of endoglucanase A previously isolated from
C. thermocellum
supernatants. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis the enzyme purified from
E. coli
exhibited two protein bands with molecular weights of 49,000 and 52,000. It had a temperature optimum at 75°C and was stable for several hours at 60°C. Endoglucanase activity was optimal between pH 5.5 and 6.5. The enzyme was insensitive against end product inhibition by glucose and cellobiose and remarkably resistant to the denaturing effects of detergents and organic solvents. It was capable of degrading, in addition to cellulosic substrates, glucans with alternating β-1,4 and β-1,3 linkages such as barley β-glucan and lichenan.
New, simple medium for selective, differential recovery of Klebsiella spp
Authors: Tomás J M , Ciurana B , Jofre J T
Published: January 2020

A highly selective, differential medium for the enumeration and isolation of Klebsiella spp. was developed. With pure cultures, 100% recovery of Klebsiella spp. was observed. Recovery of Klebsiella spp. on MacConkey-inositol-potassium tellurite (MCIK) agar was as good as or better than on MacConkey-inositol-carbenicillin agar either with pure cultures or environmental samples. Recovery and percent colony confirmation with MCIK agar were greater and easier to obtain than for other proposed Klebsiella selective media.
Use of Metabolic Inhibitors to Estimate Protozooplankton Grazing and Bacterial Production in a Monomictic Eutrophic Lake with an Anaerobic Hypolimnion
Authors: Sanders Robert W. , Porter Karen G.
Published: January 2020

Inhibitors of eucaryotes (cycloheximide and amphotericin B) and procaryotes (penicillin and chloramphenicol) were used to estimate bacterivory and bacterial production in a eutrophic lake. Bacterial production appeared to be slightly greater than protozoan grazing in the aerobic waters of Lake Oglethorpe. Use of penicillin and cycloheximide yielded inconsistent results in anaerobic water and in aerobic water when bacterial production was low. Production measured by inhibiting eucaryotes with cycloheximide did not always agree with [
3
H]thymidine estimates or differential filtration methods. Laboratory experiments showed that several common freshwater protozoans continued to swim and ingest bacterium-size latex beads in the presence of the eucaryote inhibitor. Penicillin also affected grazing rates of some ciliates. We recommend that caution and a corroborating method be used when estimating ecologically important parameters with specific inhibitors.
Biochemical Aspects of Fumaric Acid Accumulation by
Rhizopus arrhizus
Authors: Kenealy William , Zaady Eli , du Preez James C. , Stieglitz Barry , Goldberg Israel
Published: January 2020

The accumulation and excretion of fumaric acid, and to a lesser extent malic and succinic acids, by
Rhizopus arrhizus
occurs under aerobic conditions in a high-glucose medium containing a limiting amount of nitrogen and a neutralizing agent (CaCO
3
). An overall four-carbon dicarboxylic acid molar yield of up to 145% (moles of acid produced per mole of glucose utilized) is obtained after incubation for 4 to 5 days. Evidence is presented that fumarate is synthesized from pyruvate via a carboxylation reaction yielding oxaloacetate, which is then converted to malate and further on to fumarate via the reductive reactions of the tricarboxylic acid cycle. The possible formation of fumarate from the normal (oxidative) operation of the tricarboxylic acid cycle was not excluded by the data. Yield,
13
C nuclear magnetic resonance, and enzymatic activity studies were carried out in a strain of
R. arrhizus
which produces high levels of fumarate from glucose and carbonate. The observed high fumarate molar yield (greater than 100%) can therefore be explained in terms of the carboxylation of pyruvate and the operation of the reductive reactions of the tricarboxylic acid cycle under aerobic conditions.
Isolation and Characterization of an Fe(III)-Chelating Compound Produced by
Pseudomonas syringae
Authors: Torres Luis , Pérez-Ortín José E. , Tordera Vicente , Beltrán José P.
Published: January 2020

The phytopathogenic bacterium
Pseudomonas syringae
produces a fluorescent pigment when it is grown in iron-deficient media. This pigment forms a very stable Fe(III) complex that was purified in this form by using a novel procedure based on ultrafiltration and column chromatography. The Fe(III) complex has a molecular weight of 1,100 and contains 1 mol of Fe(III). The pigment is composed of an amino acid moiety with three threonines, three serines, one lysine, δ-
N
-hydroxyornithine, and a quinoline-type fluorescent chromophore. These features and its stability constant (in the range of 10
32
) suggest that the fluorescent pigment of
P. syringae
is related to the siderophores produced by another
Pseudomonas
species.
Nutritional Factors Affecting the Ratio of Solvents Produced by
Clostridium acetobutylicum
Authors: Bahl H. , Gottwald M. , Kuhn A. , Rale V. , Andersch W. , Gottschalk G.
Published: January 2020

Fermentation of whey by
Clostridium acetobutylicum
yielded butanol and acetone in a ratio of approximately 100:1. This ratio amounted to only 2:1 in synthetic media with glucose, lactose, or glucose plus galactose as substrates. Removal of citrate from whey and addition of minerals resulted in an increase in the amount of acetone produced. Experiments carried out in a chemostat with a low-phosphate synthetic medium revealed that the butanol/acetone ratio could be increased from 2:1 to 3.8:1 by cofermentation of
l
-lactate and from 2:1 to 8:1 by iron limitation. The performance of the fermentation in a low-iron glucose medium above pH 5.1 yielded
l
-lactate as the main product.
Culture Conditions for Production of Thermostable Amylase by
Bacillus stearothermophilus
Authors: Srivastava R. A. K. , Baruah J. N.
Published: January 2020

Bacillus stearothermophilus
grew better on complex and semisynthetic medium than on synthetic medium supplemented with amino acids. Amylase production on the complex medium containing beef extract or corn steep liquor was higher than on semisynthetic medium containing peptone (0.4%). The synthetic medium, however, did not provide a good yield of extracellular amylase. Among the carbohydrates which favored the production of amylase are, in order starch > dextrin > glycogen > cellobiose > maltohexaose-maltopeptaose > maltotetraose and maltotriose. The monosaccharides repressed the enzyme production, whereas inositol and
d
-sorbitol favored amylase production. Organic and inorganic salts increased amylase production in the order of KCI > sodium malate > potassium succinate, while the yield was comparatively lower with other organic salts of Na and K. Amino acids, in particular isoleucine, cysteine, phenylalanine, and aspartic acids, were found to be vital for amylase synthesis. Medium containing CaCl
2
2H
2
O enhanced amylase production over that on Ca
2+
-deficient medium. The detergents Tween-80 and Triton X-100 increased biomass but significantly suppressed amylase synthesis. The amylase powder obtained from the culture filtrate by prechilled acetone treatment was stable over a wide pH range and liquefied thick starch slurries at 80°C. The crude amylase, after (NH
4
)
2
SO
4
fractionation, had an activity of 210.6 U mg
−1
. The optimum temperature and pH of the enzyme were found to be 82°C and 6.9, respectively. Ca
2+
was required for the thermostability of the enzyme preparation.
Oxidation of Chloroform in an Aerobic Soil Exposed to Natural Gas
Authors: Strand S. E. , Shippert L.
Published: January 2020

Acclimation of a sandy soil to an air-natural gas mixture stimulated the biological oxidation of chloroform to carbon dioxide. Acetylene and methane inhibited chloroform oxidation. Chloroform oxidation continued up to 31 days in the absence of methane. Chloroform oxidation rates increased at chloroform concentrations up to 5 μg g of soil
-1
.
Agrocin-Producing
Agrobacterium tumefaciens
Strain Active against Grapevine Isolates
Authors: Webster Jocelyn , Dos Santos Maria , Thomson Jennifer A.
Published: January 2020

Agrobacterium tumefaciens
J73, a biotype 2 strain harboring a nopaline Ti plasmid, was found to produce an agrocin active against a broad range of
A. tumefaciens
strains, including grapevine isolates. Sensitivity to J73 is not encoded by a Ti plasmid. Optimal conditions for the production of the agrocin were determined.
Proteolytic activity of the ruminal bacterium Butyrivibrio fibrisolvens
Authors: Cotta M A , Hespell R B
Published: January 2020

The proteolytic activity of Butyrivibrio fibrisolvens, a ubiquitously distributed bacterial species in the gastrointestinal tracts of ruminants and other mammals, was characterized. The relative proteolytic activity (micrograms of azocasein degraded per hour per milligram of protein) varied greatly with the strain: 0 to 1 for strains D1, D16f, E21C, and X6C61; 7 to 15 for strains IL631, NOR37, S2, LM8/1B, and X10C34; and 90 to 590 for strains 12, 49 H17C, CF4c, CF3, CF1B, and R28. The activity levels of the last group of strains were equal to or greater than those found with Bacteroides amylophilus or Bacteroides ruminicola. With the exception of strain R28 activity, 90% or more of the proteolytic activity was associated with the culture fluid and not the cells. Strain 49 produced proteolytic activity constitutively, but the level of activity (units per milligram of protein) was modulated by growth parameters. With various carbohydrates added to the growth medium, the proteolytic activities of strain 49 were positively correlated with the growth rate. However, when the growth rate varied with the use of different nitrogen sources, a similar correlation was not found. The highest activity level was observed with Casamino Acids (1 g/liter), but this level was reduced by ca. 70% with Trypticase (BBL Microbiology Systems, Cockeysville, Md.) or casein (1 g/liter) and by 85% with ammonium chloride (10 mM) as the sole nitrogen source. The addition of ammonium chloride (1 to 10 mM) to media with low levels of Casamino Acids or Trypticase resulted in lower proteolytic activities but not as low as seen when the complex nitrogen sources were increased to high levels (20 g/liter).(ABSTRACT TRUNCATED AT 250 WORDS)
Aflatoxin contamination in soybeans: role of proteinase inhibitors, zinc availability, and seed coat integrity
Authors: Stössel P
Published: January 2020

Soybean trypsin inhibitors are thought to ward off pathogens. Studies with aflatoxigenic strains of Aspergillus flavus and A. parasiticus, frequent soybean contaminants, revealed that trypsin inhibitors do not affect the growth of these fungi and aflatoxin production. Further, the availability of zinc, an essential mineral for aflatoxin synthesis that was thought to explain increased aflatoxin accumulation in cooked compared with raw soybeans, was shown to decrease upon cooking. Seed coat integrity, ensuring limited access and a low moisture content, is responsible for the slow colonization of the seed by A. flavus.
Correlation of Zn2+ content with aflatoxin content of corn
Authors: Failla L J , Lynn D , Niehaus W G
Published: January 2020

Forty-nine samples from the 1983 Virginia corn harvest were analyzed for aflatoxin, zinc, copper, iron, and manganese content. Values (mean +/- standard deviation) were as follows: aflatoxin, 117 +/- 360 micrograms/kg; zinc, 22.5 +/- 3.4 mg/kg; copper, 2.27 +/- 0.56 mg/kg; iron, 40.8 +/- 18.7 mg/kg; and manganese, 5.1 +/- 1.1 mg/kg. Aflatoxin levels positively correlated with zinc (Spearman correlation coefficient, 0.385; P less than 0.006) and copper levels (Spearman correlation coefficient, 0.573; P less than 0.0001). Based on biochemical data in the literature, we believe that the correlation with zinc is important and that there may be a cause-and-effect relationship between zinc levels in corn and aflatoxin levels which are produced upon infection with Aspergillus flavus or A. parasiticus. Control of aflatoxin contamination in field corn by decreasing the zinc levels may be feasible, but no methods to decrease zinc levels are currently available.
Pentachlorophenol degradation: a pure bacterial culture and an epilithic microbial consortium
Authors: Brown E J , Pignatello J J , Martinson M M , Crawford R L
Published: January 2020

The steady-state growth of a Flavobacterium strain known to utilize pentachlorophenol (PCP) was examined when cellobiose and PCP simultaneously limited its growth rate in continuous culture. A concentration of 600 mg of PCP per liter in influent medium could be continuously degraded without affecting steady-state growth. We measured specific rates of PCP carbon degradation as high as 0.15 +/- 0.01 g (dry weight) of C per h at a growth rate of 0.045 h-1. Comparable specific rates of PCP degradation were obtained and maintained by PCP-adapted, natural consortia of epilithic microorganisms. The consortium results suggest that a fixed-film bioreactor containing a PCP-adapted natural microbial population could be used to treat PCP-contaminated water.
Demethylation of Veratrole by Cytochrome P-450 in
Streptomyces setonii
Authors: Sutherland John B.
Published: January 2020

The actinomycete
Streptomyces setonii
75Vi2 demethylates vanillic acid and guaiacol to protocatechuic acid and catechol, respectively, and then metabolizes the products by the β-ketoadipate pathway. UV spectroscopy showed that this strain could also metabolize veratrole (1,2-dimethoxybenzene). When grown in veratrole-containing media supplemented with 2,2′-dipyridyl to inhibit cleavage of the aromatic ring,
S. setonii
accumulated catechol, which was detected by both liquid chromatography and gas chromatography. Reduced cell extracts from veratrole-grown cultures, but not sodium succinate-grown cultures, produced a carbon monoxide difference spectrum with a peak at 450 nm that indicated the presence of soluble cytochrome P-450. Addition of veratrole or guaiacol to oxidized cell extracts from veratrole-grown cultures produced difference spectra that indicated that these compounds were substrates for cytochrome P-450. My results suggest that
S. setonii
produces a cytochrome P-450 that is involved in the demethylation of veratrole and guaiacol to catechol, which is then catabolized by the β-ketoadipate pathway.
Comparison of pectic enzymes produced by Erwinia chrysanthemi, Erwinia carotovora subsp. carotovora, and Erwinia carotovora subsp. atroseptica
Authors: Ried J L , Collmer A
Published: January 2020

Erwinia spp. that cause soft-rot diseases in plants produce a variety of extracellular pectic enzymes. To assess the correlation between patterns of pectic enzyme production and taxonomic classification, we compared the enzymes from representative strains. Supernatants obtained from polygalacturonate-grown cultures of nine strains of Erwinia chrysanthemi, three strains of E. carotovora subsp. carotovora, and three strains of E. carotovora subsp. atroseptica were concentrated and subjected to ultrathin-layer polyacrylamide gel isoelectric focusing. Pectate lyase, polygalacturonase, and exo-poly-alpha-D-galacturonosidase activities were visualized by staining diagnostically buffered pectate-agarose overlays with ruthenium red after incubation of the overlays with the isoelectric focusing gels. The isoelectric focusing profiles of pectate lyase and polygalacturonase were nearly identical for strains of E. carotovora subsp. carotovora and E. carotovora subsp. atroseptica, showing three pectate lyase isozymes with isoelectric points higher than 8.7 and a polygalacturonase with pI of ca. 10.2. Isoelectric focusing profiles of the E. chrysanthemi pectic enzymes were substantially different. Although there was considerable intraspecific heterogeneity, all strains produced at least four isozymes of pectate lyase, which could be divided into three groups: basic (pI, ca. 9.0 to 10.0), slightly basic (pI, ca. 7.0 to 8.5), and acidic (pI, ca. 4.0 to 5.0). Several strains of E. chrysanthemi also produced a single form of exo-poly-alpha-D-galacturonosidase (pI, ca. 8.0).(ABSTRACT TRUNCATED AT 250 WORDS)
Utilization of Xylan by Yeasts and Its Conversion to Ethanol by
Pichia stipitis
Strains
Authors: Lee Hung , Biely Peter , Latta Roger K. , Barbosa Maria F. S. , Schneider Henry
Published: January 2020

Yeasts able to grow on
d
-xylose were screened for the ability to hydrolyze xylan. Xylanase activity was found to be rare; a total of only 19 of more than 250 strains yielded a positive test result. The activity was localized largely in the genus
Cryptococcus
and in
Pichia stipitis
and its anamorph
Candida shehatae.
The ability to hydrolyze xylan was generally uncoupled from that to hydrolyze cellulose; only three of the xylan-positive strains also yielded a positive test for cellulolytic activity. Of the 19 xylanolytic strains, 2,
P. stipitis
CBS 5773 and CBS 5775, converted xylan into ethanol, with about 60% of a theoretical yield computed on the basis of the amount of
d
-xylose present originally that could be released by acid hydrolysis.
Metabolism of the herbicide bromoxynil by Klebsiella pneumoniae subsp. ozaenae
Authors: McBride K E , Kenny J W , Stalker D M
Published: January 2020

Enrichment of soil samples for organisms able to utilize the herbicide bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) as a nitrogen source yielded bacterial isolates capable of rapidly metabolizing this compound. One isolate, identified as Klebsiella pneumoniae subsp. ozaenae, could completely convert 0.05% bromoxynil to 3,5-dibromo-4-hydroxybenzoic acid and use the liberated ammonia as a sole nitrogen source. Assays of cell extracts of this organism for the ability to produce ammonia from bromoxynil revealed the presence of a nitrilase (EC 3.5.51) activity. The enzyme could not utilize 3,5-dibromo-4-hydroxybenzamide as a substrate, and no 3,5-dibromo-4-hydroxybenzamide could be detected as a product of bromoxynil transformation. Comparison of related aromatic nitriles as substrates demonstrated that the Klebsiella enzyme is highly specific for bromoxynil.
Quantitation of Adsorption of Rhizobia in Low Numbers to Small Legume Roots
Authors: Anollés Gustavo Caetano , Favelukes Gabriel
Published: January 2020

Bacteria adsorbed in low numbers to alfalfa or clover root surfaces were counted after incubation of seedlings in mineral solution with very dilute inocula (less than 10
5
bacteria per ml) of an antibiotic-resistant strain under defined conditions. After specified washing, bacteria which remained adsorbed to roots were selectively quantitated by culturing the roots embedded in yeast extract-mannitol-antibiotic agar and counting the microcolonies along the root surface; the range was from about 1 bacterium per root (estimated as the most probable number) to 50 bacteria per cm of root length (by direct counting). This simple procedure can be used with any pair of small-rooted plant and antibiotic-resistant bacterium, requires bacterial concentrations comparable to those frequently found in soils, and yields macroscopic localization and distribution data for adsorbed bacteria over the root surface. The number of adsorbed bacteria was proportional to the size of the inoculum. One of every four
Rhizobium meliloti
cells adsorbed in very low numbers to alfalfa roots resulted in the formation of a nodule. Overall adsorption of various symbiotic and nonsymbiotic bacterial strains to alfalfa and clover roots did not reflect the specificities of these legumes for their respective microsymbionts,
R. meliloti
and
R. trifolii.
Comparison of Yeast Growth in Mesquite Wood Hydrolysate
Authors: Stanlake Gary J.
Published: January 2020

Hot-water extracts of mesquite (
Prosopis glandulosa
) wood were assayed for their total carbohydrate, reducing sugar, and glucose content. These hydrolysates were then used as complete media for yeast growth. A total of 10 strains of yeasts were evaluated for their biomass production in the mesquite wood hydrolysates. Levels of utilizable carbohydrate proved to be the limiting factor for yeast growth in the hydrolysates.
Long-Term Storage of Plant-Pathogenic Bacteria in Sterile Distilled Water
Authors: Iacobellis Nicola S. , DeVay James E.
Published: January 2020

This study was made to determine the effectiveness of the preservation of plant-pathogenic bacteria in sterile distilled water. After 20 or 24 years of storage in distilled water, a very high percentage (90 to 92%) of the isolates of
Agrobacterium tumefaciens and Pseudomonas
spp. were still alive. Moreover, 12 of 13 viable (after 24 years) isolates of
P. syringae
subsp.
syringae
maintained their ability to produce syringomycin and were pathogenic to bean seedlings. The water-stored cells of two isolates of
P. syringae
subsp.
syringae
, when observed by electron microscopy, were smaller than cells of 24-h-old subcultures of bacterial cells grown in nutrient broth; the water-stored cells appeared plasmolysed with an electron-dense cytoplasm and thickened cell wall.
Ability of pH-Selected Mixed Ruminal Microbial Populations to Digest Fiber at Various pHs
Authors: Slyter Leonard L.
Published: January 2020

Inocula from pH 5.5-selected rumen microorganisms failed to digest fiber any better in batch culture at pH 5.0 or 5.5 than did inocula from pH 6.5-selected organisms. Furthermore, upon extended batch incubation, both the viable cellulolytic and amylolytic bacteria became increasingly associated with the fiber portion and less with the liquid portion of the cultures.
High-efficiency transformation of Streptococcus lactis protoplasts by plasmid DNA
Authors: Simon D , Rouault A , Chopin M C
Published: January 2020

Streptococcus lactis IL1403 protoplasts were transformed by plasmid pIL204 (5.5 kilobases), which conferred erythromycin resistance with an average efficiency of 5 X 10(6) transformants per microgram of supercoiled DNA. The procedure used and transformation efficiencies obtained were close to those described for Bacillus subtilis (G. Chang and S. N. Cohen, Mol. Gen. Genet. 168:111-115, 1979).
Photoreactivation of ultraviolet-irradiated, plasmid-bearing, and plasmid-free strains of Bacillus anthracis
Authors: Knudson G B
Published: January 2020

The effects of toxin- and capsule-encoding plasmids on the kinetics of UV inactivation of various strains of Bacillus anthracis were investigated. Plasmids pXO1 and pXO2 had no effect on bacterial UV sensitivity or photoreactivation. Vegetative cells were capable of photoreactivation, but photo-induced repair of UV damage was absent in B. anthracis Sterne spores.
Phenotypic characteristics of coliform and noncoliform bacteria from a public water supply compared with regional and national clinical species
Authors: Edberg S C , Piscitelli V , Cartter M
Published: January 2020

During the summer and fall of 1984, elevated total coliform counts were observed in the distribution system of a public water supply serving 350,000 people in south central Connecticut. As part of an investigation of possible health risks associated with the presence of bacteria in the water supply, bacterial isolates from the distribution system were compared with bacterial isolates of the same species obtained from a large regional teaching hospital and from a national compendium of clinical isolates. Characteristics analyzed included phenotypic metabolic activity, antimicrobial susceptibilities to clinically utilized antibiotics, temperature tolerance at 44.5 degrees C, and beta-glucuronidase activity in single-test form and on a selective medium. Environmental isolates lacked known plasmid-mediated characteristics, with the exception of one Escherichia coli isolate which showed some antibiotic resistance. Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, and Enterobacter agglomerans from all sources were temperature tolerant and yielded positive fecal coliform tests. Only E. coli showed beta-glucuronidase activity (both in a single biochemical test and on a selective medium). No single characteristic analyzed was sufficient to establish an organism as either environmental or clinical in origin.