bluuebunny/crossref_metadata_2025 huggingface dataset:
Uncoupling of Methanogenesis from Growth of
Methanosarcina barkeri
by Phosphate Limitation
Authors: Archer David B.
Published: January 2020

Production of methane by
Methanosarcina barkeri
from H
2
-CO
2
was studied in fed-batch culture under phosphate-limiting conditions. A transition in the kinetics of methanogenesis from an exponentially increasing rate to a constant rate was due to depletion of phosphate from the medium. The period of exponentially increasing rate of methanogenesis was extended by increasing the initial concentration of phosphate in the medium. Addition of phosphate during the constant period changed the kinetics to an exponentially increasing rate of methanogenesis, indicating the reversibility of phosphate depletion. The relation between methanogenesis and growth of
M. barkeri
was investigated by measuring the incorporation of phosphorus, supplied as KH
2
32
PO
4
, in the medium. At a low (1 μM) initial concentration of phosphate in the medium and during the constant period of methanogenesis, there was no net cell growth. At a higher (10 μM) initial concentration of phosphate, cell growth proceeded linearly with time after phosphate had been removed from the medium by uptake into cells.
Severe hepatotoxicity caused by the tropical cyanobacterium (blue-green alga) Cylindrospermopsis raciborskii (Woloszynska) Seenaya and Subba Raju isolated from a domestic water supply reservoir
Authors: Hawkins P R , Runnegar M T , Jackson A R , Falconer I R
Published: January 2020

Cylindrospermopsis raciborskii, a tropical blooming species of cyanobacterium (blue-green alga), was isolated from the domestic water supply reservoir on Palm Island, a continental island off the tropical northeast coast of Australia. This species, not previously known to be toxic, was shown to be severely hepatotoxic for mice. The 50% lethal dose at 24 h after injection was found to be 64 +/- 5 mg of freeze-dried culture per kg of mouse. The principal lesion produced was centrilobular to massive hepatocyte necrosis, but various degrees of injury were also seen in the kidneys, adrenal glands, lungs, and intestine. The possible implication of this finding in relation to an incident of hepatoenteritis in humans living on the island is discussed.
Relation of 8-ketotrichothecene and zearalenone analog structure to inhibition of mitogen-induced human lymphocyte blastogenesis
Authors: Forsell J H , Pestka J J
Published: January 2020

The 50% effective doses of fusarenon X, nivalenol, deoxynivalenol, and 15-acetyldeoxynivalenol required to reduce [3H]thymidine uptake in mitogen-stimulated human lymphocytes by 50% were 18, 72, 140, and 240 ng/ml, respectively. These results indicated that lymphotoxicity of 8-ketotrichothecenes decreased according to the C-4 substituent order acetyl greater than hydroxyl greater than hydrogen, whereas acetylation of position C-15 of deoxynivalenol caused a slight decrease in in vitro toxicity. The 50% effective doses for zearalenone, alpha-zearalenol, beta-zearalenol, alpha-zearalanol, and beta-zearalanol were 3,500, 6,300, 36,000, 3,750, and 33,000 ng/ml, respectively, suggesting that a keto group or alpha-hydroxyl at the position C-6' contributed to the lymphotoxicity of the parent molecule. The inhibitory effects of zearalenone analogs observed in the blastogenesis assay did not correlate with the estrogenic potencies of these compounds. All 8-ketotrichothecenes and zearalenone analogs tested were capable of inhibiting B- and T-cell subsets stimulated by a mitogen panel of leukoagglutinin, concanavalin A, and pokeweed mitogen.
Stability of T-2 mycotoxin in aqueous media
Authors: Trusal L R
Published: January 2020

3H-labeled T-2 mycotoxin was dissolved in various aqueous media and stored for up to 3 weeks at 4, 22, and 37 degrees C. At periods ranging from 1 to 21 days, aliquots were assayed by thin-layer chromatography. Thin-layer chromatography plates were scanned for breakdown products by use of a radioisotope scanner, and breakdown products were identified based on their comigration with known standards. Results indicated that T-2 toxin was more stable in tissue culture medium with or without serum, than in Hanks balanced salt solution (HBSS), at all temperatures. The metabolites HT-2, T-2 triol, and T-2 tetraol were detected as early as 1 day (HBSS; 37 degrees C) and as late as 3 weeks (HBSS; 4 degrees C) after storage. Stability of the toxin in aqueous media decreased with increasing temperature.
Fibronectin enhances transfection of Staphylococcus aureus
Authors: Thompson N E , Bergdoll M S , Pattee P A
Published: January 2020

The factor in normal sera primarily responsible for the enhancement of transfection (and transformation) of Staphylococcus aureus was identified as fibronectin. Serum samples which were depleted of fibronectin by affinity chromatography showed a marked decrease in enhancing activity. Fibronectin isolated from sera of several animal species demonstrated enhancing activity.
Agar overlay method to measure adherence of Staphylococcus epidermidis to four plastic surfaces
Authors: Mackenzie A M , Rivera-Calderon R L
Published: January 2020

The comparative adherence of seven strains of Staphylococcus epidermidis to plastic surfaces was measured by an agar overlay technique in which adherent organisms were counted by their ability to form colonies under an agar overlay. The degree of adherence to plastics decreased in the order polystyrene, polyvinyl chloride, Silastic, and polytetrafluoroethylene.
Incidence of Plasmids in
Thermus
spp. Isolated in Yellowstone National Park
Authors: Munster Michael J. , Munster Ann P. , Sharp Richard J.
Published: January 2020

Forty-eight strains of
Thermus
spp. were isolated from thermal sites in Yellowstone National Park, Wyo., and 62.5% showed evidence of plasmid DNA. Attempts to assign function to the plasmid DNA were unsuccessful, and the presence of plasmid DNA could not be correlated with antibiotic or heavy metal resistance. A number of these cryptic plasmids are now being investigated for their potential as vectors for molecular cloning in
Thermus
spp.
Identification and characterization of antimicrobial activity in two yeast genera
Authors: Bilinski C A , Innamorato G , Stewart G G
Published: January 2020

A general screening test for the expression of antibacterial activity was performed on over 400 cultures belonging to 31 yeast genera. Of these cultures, only two, Kluyveromyces thermotolerans and Kloeckera apiculata, were found to produce zones of inhibition of bacterial growth on Diagnostic Sensitivity Test Agar medium supplemented with 0.002% methylene blue. Of nine bacteria used as test organisms, only Lactobacillus plantarum and Bacillus megaterium were inhibited. No antibacterial activity was evident against four gram-negative bacteria used in this study. Optimal activities were found to be expressed after yeasts were grown at pH 6. A requirement for cultivation in the presence of methylene blue added to culture media for the expression of apparent antibacterial activity was demonstrated.
Effect of reducing-equivalent disposal and NADH/NAD on deamination of amino acids by intact rumen microorganisms and their cell extracts
Authors: Hino T , Russell J B
Published: January 2020

When mixed rumen microorganisms were incubated in media containing the amino acid source Trypticase, both monensin and carbon monoxide (a hydrogenase inhibitor) decreased methane formation and amino acid fermentation. Both of the methane inhibitors caused a significant increase in the ratio of intracellular NADH to NAD. Studies with cell extracts of rumen bacteria and protozoa indicated that the ratio of NADH to NAD had a marked effect on the deamination of reduced amino acids, in particular branched-chain amino acids. Deamination was inhibited by the addition of NADH and was stimulated by methylene blue, an agent that oxidizes NADH. Neutral and oxidized amino acids were unaffected by NADH. The addition of small amounts of 2-oxoglutarate greatly enhanced the deamination of branched-chain amino acids and indicated that transamination via glutamate dehydrogenase was important. Formation of ammonia from glutamate was likewise inhibited by NADH. These experiments indicated that reducing-equivalent disposal and intracellular NADH/NAD ratio were important effectors of branched-chain amino acid fermentation.
Endotoxin removal by charge-modified filters
Authors: Gerba C P , Hou K
Published: January 2020

The effects of positively charged nylon and depth (cellulose-diatomaceous earth) filters on endotoxin removal from various solutions were evaluated. The charged filter media removed significant amounts of Escherichia coli and natural endotoxin from tap water, distilled water, sugars, and NaCl solutions; no significant removal of endotoxin was observed with negatively charged filter media. The extent of removal was influenced by pH, the presence of salts, and organic matter. Such media may be useful for the control of endotoxins in raw-product water or solutions used to prepare parenteral drug products or in other fluids where endotoxin control is desired.
Nitrogen utilization in bacterial isolates from the equine cecum
Authors: Maczulak A E , Dawson K A , Baker J P
Published: January 2020

A total of 114 bacterial isolates were obtained from the cecal contents of two mature cecally fistulated horses on a habitat-simulating medium containing 40% energy-depleted cecal fluid. Of these isolates, 108 were maintained in pure cultures and were tentatively grouped on the basis of cell morphology and physiological characteristics. Gram-negative rods (50.9%), gram-positive rods (22.8%), and gram-positive cocci (21.9%) represented the largest groups isolated from these animals. Fifty isolates were tested for their ability to grow in media containing urea, ammonia, peptones, or amino acids as sole nitrogen sources. None of the isolates had a unique requirement for urea or ammonia since nitrogen derived from peptones, amino acids, or both supported growth as well as did ammonia or urea in a low nitrogen medium. Of the cecal isolates, 18% were able to use urea for growth, and 20.5% were able to grow with ammonia as the sole nitrogen source. All organisms grew in the experimental media containing peptones as the sole nitrogen source. Urease activity was detected in only 2 of 114 isolates tested. The inability of isolates to use urea or ammonia as nitrogen sources may have been a reflection of growth conditions in the habitat-stimulating medium used for isolation, but it could also suggest that many cecal bacteria require nitrogen sources other then ammonia or urea for growth.
Production of High-Viscosity Whey Broths by a Lactose-Utilizing
Xanthomonas campestris
Strain
Authors: Schwartz Robert D. , Bodie Elizabeth A.
Published: January 2020

Xanthomonas campestris
BB-1L was isolated by enrichment and selection by serial passage in a lactose-minimal medium. When BB-1L was subsequently grown in medium containing only 4% whey and 0.05% yeast extract, the lactose was consumed and broth viscosities greater than 500 cps at a 12 s
−1
shear rate were produced. Prolonged maintenance in whey resulted in the loss of the ability of BB-1L to produce viscous broths in whey, indicating a reversion to preferential growth on whey protein, like the parent strain.
Studies on the sensitivity and specificity of the Limulus amebocyte lysate test and rabbit pyrogen assays
Authors: Devleeschouwer M J , Cornil M F , Dony J
Published: January 2020

The sensitivity and specificity of the Limulus amebocyte lysate test and rabbit pyrogen assay were studied by means of artificially contaminated parenterals. Various gram-negative and gram-positive bacterial strains were used as was one strain of the yeast Candida albicans. The numbers of organisms needed to elicit positive responses in distilled water and normal saline were recorded and compared. The sensitivity and specificity of the Limulus amebocyte lysate assay for the detection of bacterial endotoxin from gram-negative bacteria were demonstrated. Variable results were recorded with gram-positive bacteria and Candida albicans.
Isolation and characterization of Flavobacterium strains that degrade pentachlorophenol
Authors: Saber D L , Crawford R L
Published: January 2020

Bacteria able to mineralize 100 to 200 ppm of pentachlorophenol (PCP) were isolated by selective enrichment from PCP-contaminated soils from three geographic areas of Minnesota. Although differing somewhat in their responses to various biochemical and biophysical tests, all strains were assigned to the genus Flavobacterium. Five representative strains were examined in detail. All strains metabolized PCP as a sole source of carbon and energy; 73 to 83% of all carbon in the form of [U-14C]PCP was returned as 14CO2, with full liberation of chlorine as chloride. A comparison between strains in their ability to metabolize PCP showed some strains to be more efficient than others. Guanine-plus-cytosine contents of DNA ranged from 58.8 to 63.8%, and DNA/DNA hybridization studies with total DNA digests suggested substantial genetic homology between strains. All strains were shown to possess an 80- to 100-kilobase plasmid, and evidence suggested the presence of a larger plasmid (greater than 200 kilobases).
Yellow Blotch of
Pleurotus ostreatus
Authors: Bessette Alan E. , Kerrigan R. W. , Jordan D. C.
Published: January 2020

Yellow blotch disease of the oyster mushroom (
Pleurotus ostreatus
) was first observed in a commercial mushroom farm in California in 1983. The disease, caused by
Pseudomonas agarici
, is characterized by primordia, with yellow droplets on their surface, which become stunted, yellow to orange, and deformed as they mature.
Methanogenic Bacteria, Including an Acid-Tolerant Strain, from Peatlands
Authors: Williams Richard T. , Crawford Ronald L.
Published: January 2020

Five pure cultures of methanogenic bacteria were isolated from Minnesota peatlands by enrichment culture techniques. One strain, identified as a member of the family
Methanobacteriaceae
by antigenic fingerprinting, was acid tolerant and able to produce methane at pH 3.1. Growth could not be demonstrated at pH less than 5.3.
Production of N2O and CO2 during the reduction of NO2- by Lactobacillus lactis TS4
Authors: Dodds K L , Collins-Thompson D L
Published: January 2020

N2O was produced during the reduction of NO2- by resting cells of Lactobacillus lactis TS4. At an initial NO2- concentration of 69 micrograms/ml, the rate of N2O production was 1.97 nmol/min per mg of protein, and the recovery of reduced NO2- -N as N2O-N after 24 h was 77%. Higher initial NO2- concentrations decreased both the rate of production of N2O and the recovery of reduced NO2- -N. CO2 production increased during NO2- reduction.
Improved method for production of antibodies against T-2 toxin and diacetoxyscirpenol in rabbits
Authors: Zhang G S , Schubring S L , Chu F S
Published: January 2020

A new, improved approach for the production of antibodies against T-2 toxin and diacetoxyscirpenol (DAS) was developed. The method involves the use of immunogens which were prepared by conjugating O-carboxymethoxyl oxime (CMO) derivatives of both toxins to bovine serum albumin (BSA). Isomers a and b of CMO-T-2 toxin and isomer b of CMO-DAS were tested. Antibodies against both toxins were demonstrated as early as 4 weeks after immunization. a-CMO-T-2-BSA conjugate was a better immunogen than the b isomer, and the highest titers (6,000) were reached 14 weeks after immunization and one booster injection. Antibody titers for rabbits immunized with the b isomer of CMO-T-2 never reached more than 2,000. The specificity of antibodies obtained from rabbits after immunization with CMO-T-2-BSA was similar to that of hemisuccinate-T-2-BSA. Anti-b-T-2 antibodies had slightly higher cross-reactivity with H-T-2 toxin than did the antibody obtained from rabbits immunized with the conjugate of the a isomer. The relative cross-reactivities of anti-a-CMO-T-2 antibody with T-2, acetyl-T-2, H-T-2, T-2-triol, 3'-OH-T-2, and T-2 tetraol were 1, 4.5, 5.7, 250, 500, and 3,000, respectively. The relative cross-reactivities of anti-b-T-2 antibody with T-2, acetyl-T-2, H-T-2, and T-2 triol were 1, 2, 3, and 488, respectively. Antibodies against b-CMO-DAS showed a high degree of cross-reactivity with monoacetoxyscirpenols (MAS). The relative cross-reactivities of anti-B-DAS antibody with DAS, 4-MAS, 15-MAS, acetyl-deoxynivalenol, T-2-toxin, acetyl-T-2, and neosolaniol were 1, 4, 5, 76, 107, 147, and 266, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Evidence for NH4+ switch-off regulation of nitrogenase activity by bacteria in salt marsh sediments and roots of the grass Spartina alterniflora
Authors: Yoch D C , Whiting G J
Published: January 2020

The regulatory effect of NH4+ on nitrogen fixation in a Spartina alterniflora salt marsh was examined. Acetylene reduction activity (ARA) measured in situ was only partially inhibited by NH4+ in both the light and dark after 2 h. In vitro analysis of bulk sediment divided into sediment particles, live and dead roots, and rhizomes showed that microbes associated with sediment and dead roots have a great potential for anaerobic C2H2 reduction, but only if amended with a carbon source such as mannose. Only live roots had significant rates of ARA without an added carbon source. In sediment, N2-fixing mannose enrichment cultures could be distinguished from those enriched by lactate in that only the latter were rapidly inhibited by NH4+. Ammonia also inhibited ARA in dead and live roots and in surface-sterilized roots. The rate of this inhibition appeared to be too rapid to be attributed to the repression and subsequent dilution of nitrogenase. The kinetic characteristics of this inhibition and its prevention in root-associated microbes by methionine sulfoximine are consistent with the NH4+ switch-off-switch-on mechanism of nitrogenase regulation.
Determination of the intracellular concentration of ethanol in Saccharomyces cerevisiae during fermentation
Authors: Dombek K M , Ingram L O
Published: January 2020

Considerable controversy exists concerning the intracellular concentration of ethanol in Saccharomyces cerevisiae during fermentation. This controversy results from problems in the measurement of the intracellular concentration of compounds like ethanol, which are being produced rapidly by metabolism and potentially diffuse rapidly from the cell. We used a new method for the determination of intracellular ethanol based on the exclusion of [14C]sorbitol to estimate the aqueous cell volume. This method avoided many of the technical problems in previous reports. Our results indicate that the extracellular concentrations of ethanol in fermenting suspensions of S. cerevisiae are less than or equal to those in the intracellular environment and do not increase to the high levels previously reported even during the most active stages of batch fermentation.
Concentration of viruses in beef extract by flocculation with ammonium sulfate
Authors: Shields P A , Farrah S R
Published: January 2020

Bacteriophages and enteroviruses in water were adsorbed to positively charged filters (Virosorb 1MDS [AMF Cuno, Inc., Meriden, Conn.] or Seitz S [Republic Filters, Milldaler, Conn.]). Adsorbed viruses were eluted by treating the filters with 10% beef extract, pH 9. Organic flocculation of the beef extract at pH 3.5 permitted recovery of more than 40% of the enteroviruses tested but less than 15% of the bacteriophages present. A method was developed that uses salts at pH 7 to flocculate beef extract. Two volumes of saturated ammonium sulfate were added to beef extract, and both enteroviruses and bacteriophages were adsorbed to the flocs that formed. Greater than 70% of the enteroviruses and bacteriophages were recovered by centrifuging the sample and suspending the flocs in a small volume of distilled water.
Accumulation of Poly (β-Hydroxybutyrate) by Halobacteria
Authors: Fernandez-Castillo R. , Rodriguez-Valera F. , Gonzalez-Ramos J. , Ruiz-Berraquero F.
Published: January 2020

Some species of extremely halophilic archaebacteria,
Halobacteriaceae
, have been shown to accumulate large amounts of poly (β-hydroxybutyrate) under conditions of nitrogen limitation and abundant carbon source. The production of poly (β-hydroxybutyrate), at least in large quantities, was restricted to two carbohydrate-utilizing species,
Halobacterium mediterranei
and
H. volcanii.
In addition to the nutrients in the media, the salt concentration also influenced poly (β-hydroxybutyrate) accumulation, which was greater at lower salt concentrations. The possible application of these microorganisms for the production of biodegradable plastics is discussed.
Effect of Sterilization by Dry Heat or Autoclaving on Bacterial Penetration through Berea Sandstone
Authors: Jenneman Gary E. , McInerney Michael J. , Crocker Michael E. , Knapp Roy M.
Published: January 2020

A study was undertaken to determine why bacteria could penetrate lengths of consolidated sandstone (Berea) faster when the sandstone was sterilized by autoclaving than when dry heat (150°C, 3 h) was used. Changes in permeability, porosity, and pore entrance size of the rock as a result of autoclaving were not sufficient to explain the differences in penetration times observed, but electron dispersion spectroscopy and electron microscopy of the rock revealed changes in mineral composition and clay morphology. Autoclaved cores contained more chloride than dry-heated cores, and the clays of autoclaved cores were aggregated and irregularly shaped. Therefore, the decreases in bacterial penetration rates caused by autoclave sterilization were probably the result of a change in surface charge of the pores of the rock and of a reduction in surface area of clays available for adhesion. The results implied that dry-heat sterilization was preferable to autoclaving when examining biotic and abiotic interactions in a native-state rock model.
Adhesion of the clay minerals montmorillonite, kaolinite, and attapulgite reduces respiration of Histoplasma capsulatum
Authors: Lavie S , Stotzky G
Published: January 2020

The respiration of three phenotypes of Histoplasma capsulatum, the causal agent of histoplasmosis in humans, was markedly reduced by low concentrations of montmorillonite but was reduced less by even higher concentrations of kaolinite or attapulgite (palygorskite). The reduction in respiration followed a pattern that suggested saturation-type kinetics: an initial sharp reduction that occurred with low concentrations of clay (0.01 to 0.5% [wt/vol]), followed by a more gradual reduction with higher concentrations (1 to 8%). Increases in viscosity (which could impair the movement of O2) caused by the clays were not responsible for the reduction in respiration, and the clays did not interfere with the availability of nutrients. Scanning electron microscopy after extensive washing showed that the clay particles were tightly bound to the hyphae, suggesting that the clays reduced the rate of respiration of H. capsulatum by adhering to the mycelial surface and, thereby, interfered with the movement of nutrients, metabolites, and gases across the mycelial wall.
Interactions between clay minerals and siderophores affect the respiration of Histoplasma capsulatum
Authors: Lavie S , Stotzky G
Published: January 2020

The reduction in the respiration of Histoplasma capsulatum in broth culture caused by montmorillonite appeared to be the result, in part, of the interference by the clay with the iron nutrition of the fungus. This interference was apparently the result of the adsorption by the clay of the iron-transporting siderophore (deferricoprogen B) produced by the fungus, as the reduction in respiration was partially alleviated by the addition of foreign siderophores. Neither kaolinite nor attapulgite (palygorskite) appeared to adsorb significant amounts of the siderophores, probably because of the low cation exchange capacity and specific surface area of kaolinite and the inaccessibility of adsorption sites in the fibrous attapulgite. These observations, in addition to the adhesion of montmorillonite to the hyphae, suggest mechanisms that may explain the discrete geographic distribution of this fungus, which is pathogenic to humans and which has been isolated essentially only from soils that do not contain montmorillonite.
Nitrogen-Fixing Pseudomonads Isolated from Roots of Plants Grown in the Canadian High Arctic
Authors: Lifshitz Ran , Kloepper Joseph W. , Scher Fran M. , Tipping Elizabeth M. , Laliberté Monique
Published: January 2020

Root-associated bacteria capable of reducing acetylene to ethylene (biological nitrogen fixation) were isolated from various native plants grown in the Canadian High Arctic. All the strains belonged to the genus
Pseudomonas
but varied in several physiological characteristics. The rates of acetylene reduction at 14 or 20°C were higher than at 25 or 9°C. Six strains reduced acetylene at 4°C. All the strains exhibited chemotaxis to
l
-asparagine in semisolid agar at 4 to 25°C. Eleven strains colonized roots of canola (
Brassica campestris
cv. Tobin) in field soil at population densities of log 4.3 to log 5.1 CFU/g of fresh root at 14°C and log 4.0 to log 5.2 CFU/g of fresh root at 25°C. Some of these nitrogen-fixing pseudomonad strains demonstrated a competitive advantage for root colonization over other rhizosphere bacteria at low temperatures. The combined capabilities of nitrogen fixation and root colonization by diazotrophic pseudomonads may be useful for the development of a biofertilizer inoculant for temperate and cold regions.
Biochemical classification of Clostridium botulinum type C and D strains and their nontoxigenic derivatives
Authors: Oguma K , Yamaguchi T , Sudou K , Yokosawa N , Fujikawa Y
Published: January 2020

The biochemical properties of 11 toxigenic and 10 nontoxigenic type C and D strains of Clostridium botulinum were studied. All of the strains examined were motile and hemolytic and produced lipase and liquid gelatin. Fermentation of several sugars and the production of lecithinase, indole, and hydrogen sulfide varied with the strain. The strains were classified into four groups based on their sugar fermentation profiles. The resulting classification was identical to the classification which had been proposed from the relationship between toxin production and phages and similar to the grouping based on the nature of toxin antigenic structures. Lecithinase production was negative in the cells belonging to group III, and indole and hydrogen sulfide production was negative in the cells of groups III and IV. Strains belonging to groups III and IV have many characteristics different from those of groups I and II.
Lectin Binding to the Root and Root Hair Tips of the Tropical Legume
Macroptilium atropurpureum
Urb
Authors: Ridge R. W. , Rolfe B. G.
Published: January 2020

Ten fluorescein isothiocyanate-labeled lectins were tested on the roots of the tropical legume
Macroptilium atropurpureum
Urb. Four of these (concanavalin A, peanut agglutinin,
Ricinis communis
agglutinin I [RCA-I], wheat germ agglutinin) were found to bind to the exterior of root cap cells, the root cap slime, and the channels between epidermal cells in the root elongation zone. One of these lectins, RCA-I, bound to the root hair tips in the mature and emerging hair zones and also to sites at which root hairs were only just emerging. There was no RCA-I binding to immature trichoblasts. Preincubation of these lectins with their hapten sugars eliminated all types of root cell binding. By using a microinoculation technique, preincubation of the root surface with RCA-I lectin was found to inhibit infection and nodulation by
Rhizobium
spp. Preincubation of the root surface with the RCA-I hapten β-
d
-galactose or a mixture of RCA-I lectin and its hapten failed to inhibit nodulation. Application of RCA-I lectin to the root surface caused no apparent detrimental effects to the root hair cells and did not prevent the growth of root hairs. The lectin did not prevent
Rhizobium
sp. motility or viability even after 24 h of incubation. It was concluded that the RCA-I lectin-specific sugar β-
d
-galactose may be involved in the recognition or early infection stages, or both, in the
Rhizobium
sp. infection of
M. atropurpureum.
Bioluminescence for USP sterility testing of pharmaceutical suspension products
Authors: Bussey D M , Tsuji K
Published: January 2020

Bioluminescence measurement significantly improved the accuracy, sensitivity, precision, and reliability of the current visual endpoint determination for the USP sterility test and eliminated the day 7 transfer/dilution step required for testing suspension products. Thirteen strains of bacteria and fungi (representing potential contaminants in sterile products), three pharmaceutical suspension products, and four media were used in the experiment. No interference from suspension products was encountered in the detection of microbial growth by the bioluminescence measurement. The poor fungal growth encountered was attributed to insufficient diffusion of oxygen into the medium and was circumvented by use of a large tube size (38 by 200 mm) or by vortexing the medium once during the 2-week incubation period. Bioluminescence measurement would facilitate automated handling of the sterility test endpoint readout operation. The optimum parameters of bioluminescence measurement for application in sterility testing were determined.
Construction of Lactose-Assimilating and High-Ethanol-Producing Yeasts by Protoplast Fusion
Authors: Farahnak F. , Seki T. , Ryu Dewey D. Y. , Ogrydziak D.
Published: January 2020

The availability of a yeast strain which is capable of fermenting lactose and at the same time is tolerant to high concentrations of ethanol would be useful for the production of ethanol from lactose.
Kluyveromyces fragilis
is capable of fermenting lactose, but it is not as tolerant as
Saccharomyces cerevisiae
to high concentrations of ethanol. In this study, we have used the protoplast fusion technique to construct hybrids between auxotrophic strains of
S. cerevisiae
having high ethanol tolerance and an auxotrophic strain of lactose-fermenting
K. fragilis
isolated by ethyl methanesulfonate mutagenesis. The fusants obtained were prototrophic and capable of assimilating lactose and producing ethanol in excess of 13% (vol/vol). The complementation frequency of fusion was about 0.7%. Formation of fusants was confirmed by the increased amount of chromosomal DNA per cell. Fusants contained 8 × 10
−8
to 16 × 10
−8
μg of DNA per cell as compared with about 4 × 10
−8
μg of DNA per cell for the parental strains, suggesting that multiple fusions had taken place.
Enumeration of polysaccharide-degrading Bacteroides species in human feces by using species-specific DNA probes
Authors: Kuritza A P , Shaughnessy P , Salyers A A
Published: January 2020

DNA probes that are specific for each of five predominant species of human colonic Bacteroides (B. thetaiotaomicron, B. uniformis, B. distasonis, "Bacteroides group 3452-A", and B. ovatus) were used to detect and enumerate these species in fecal samples from two adult volunteers. These five species are capable of fermenting many of the complex polysaccharides that are thought to be sources of carbon and energy for bacteria in the colon. Estimates for the concentrations of some of these species in feces have not been previously available because of the difficulties in differentiating colonic Bacteroides spp. by conventional biochemical tests. Our results indicate that all the species except B. ovatus were present in high numbers (greater than 10(9)/g [dry weight]) in the feces of both volunteers. However, the concentrations of the more versatile polysaccharide-degrading species within this group of organisms (7.6 X 10(9) to 12.0 X 10(9)/g [dry weight] for B. thetaiotaomicron; 2.9 X 10(9) to 6.3 X 10(9)/g [dry weight] for "Bacteroides group 3452-A") did not differ significantly from the concentrations of less versatile polysaccharide-degrading species (1.2 X 10(10) to 2.0 X 10(10)/g [dry weight] for B. uniformis; 5.8 X 10(9) to 8.4 X 10(9)/g [dry weight] for B. distasonis). B. ovatus was not detectable by our method. Since our lower limit of detection is approximately 1 X 10(9) to 2 X 10(9)/g (dry weight) of feces, this is consistent with earlier estimates that indicated that the concentration of B. ovatus in feces is near or below this value.(ABSTRACT TRUNCATED AT 250 WORDS)
Isolation of protozoa from water associated with a legionellosis outbreak and demonstration of intracellular multiplication of Legionella pneumophila
Authors: Barbaree J M , Fields B S , Feeley J C , Gorman G W , Martin W T
Published: January 2020

At the site of a legionellosis outbreak, amoebae and two ciliates, Tetrahymena sp. and Cyclidium sp., were isolated from cooling-tower water containing Legionella pneumophila. The Tetrahymena sp. and the amoebae repeatedly showed the ability to support intracellular multiplication of L. pneumophila. Both were isolated from cooling towers specifically implicated as the source for the spread of legionellosis. These protozoa may be reservoirs supporting the survival and multiplication of virulent legionellae in cooling-tower water.
Stimulation of
Agrobacterium tumefaciens
Growth by
Azotobacter vinelandii
Ferrisiderophores
Authors: Page William J. , Dale Phyllis L.
Published: January 2020

Azotobacter vinelandii
stimulated the growth of
Agrobacterium tumefaciens
H2, H23, H24, H27, and ATCC 15955 on media containing insoluble iron sources. The
Azotobacter vinelandii
siderophores appeared to promote
Agrobacterium tumefaciens
growth by solubilizing mineral iron, and the ferrisiderophores so formed then acted as iron sources for
Agrobacterium tumefaciens.
Agrobactin, the
Agrobacterium
siderophore, appeared to be inefficient in solubilizing mineral iron directly.
Rhizobins, a Group of Peptides in the Free-Amino-Acid Pool of the Soybean-
Rhizobium
System
Authors: Garay Andrew S. , Ahlgren Joy A. , Gonzalez Mark A. , Stasney Mark A. , Madtes Paul C.
Published: January 2020

Free-living
Rhizobium
(according to
Bergey's Manual of Systematic Bacteriology
, [1984, The Williams & Wilkins Co., Baltimore],
Bradyrhizobium
)
japonicum
was found to release a peptide into the nutrient media. Soybean nodules contained this peptide and exuded it into the soil. The name “rhizobin A” is suggested for this peptide. Nodules also contained another peptide, rhizobin B, as well as an unidentified, ninhydrin-positive compound, rhizobin C. The three peptides were confined to the free-amino-acid pool of the soluble fraction and eluted consecutively from a cation-exchange column. Rhizobin A was isolated in a highly purified form; its molecular mass was approximately 1,600 daltons as determined by Sephadex gel filtration and mass spectrometry. The amino-acid composition could be determined only approximately, because a long time was necessary for acid hydrolysis, possibly due to unusual linkages. The rhizobin concentration in soybean nodules continually increased during 50 days of growth, from 2 to approximately 400 μg/g (fresh weight). When combined nitrogen was added to nodulated soybean and subsequently removed, nitrogenase activity, nodulation, and nodule growth first decreased and then recovered. The relative amount of rhizobin A followed a similar pattern. Rhizobins were not detected in the roots, stems, and leaves of nodulated soybean plants. They were present in
Lupinus
nodules, but absent in alder nodules.
Trichothecene Biosynthesis in
Fusarium sporotrichioides
: Origin of the Oxygen Atoms of T-2 Toxin
Authors: Desjardins Anne E. , Plattner Ronald D. , Vanmiddlesworth Frank
Published: January 2020

Mass spectral analysis of T-2 toxin formed during the growth of
Fusarium sporotrichioides
(ATCC 24043) in the presence of H
2
18
O showed incorporation of up to three
18
O atoms per toxin molecule. The carbonyl oxygens of the acetates at C-4 and C-15 and of the isovalerate at C-8 were derived from H
2
O. Toxin formed in the presence of
18
O molecular oxygen incorporated up to six
18
O atoms per toxin molecule. The overall incorporation was 78 and 92% of toxin molecules labeled for H
2
18
O and
18
O
2
labeled samples, respectively. The oxygens of position 1, the 12,13-epoxide, and the hydroxyl groups at C-3, C-4, C-8, and C-15 were all derived from molecular oxygen.
Cloning of a
Serratia marcescens
Gene Encoding Chitinase
Authors: Fuchs R. L. , McPherson S. A. , Drahos D. J.
Published: January 2020

Serratia marcescens
, a chitinase-producing microorganism, was shown to produce five unique chitinolytic proteins with subunit molecular masses of 21, 36, 48, 52, and 57 kilodaltons. A cosmid library of
S. marcescens
DNA was constructed in the broad-host-range cosmid pLAFR1 and screened in
Escherichia coli
for clones capable of degrading chitin. A total of four independent clones (22- to 27-kilobase inserts) were isolated, characterized by restriction endonuclease digestion, and shown to share a common 9.5-kilobase
Eco
R1 fragment apparently encoding the same 57-kilodalton chitinase, the most abundant chitinase produced by
S. marcescens
. Chitinase expression from these constructs in both
E. coli
and
Pseudomonas fluorescens
701E1 is apparently driven by an
S. marcescens
promoter. The significantly higher chitinase levels produced in
E. coli
relative to those in
P. fluorescens
701E1 suggest that
E. coli
may recognize this promoter sequence more efficiently than
P. fluorescens.
Cloning and constitutive expression of the N-acetylneuraminate lyase gene of Escherichia coli
Authors: Aisaka K , Uwajima T
Published: January 2020

The N-acetylneuraminate (NANA) lyase (EC 4.1.3.3) gene from Escherichia coli was self-cloned in E. coli. Transformants were selected by complementation of a NANA lyase-deficient E. coli strain. One clone was found to produce NANA lyase, and it contained a recombinant plasmid, pNAL1, with a 9.0-kilobase HindIII insert. The cloning of the NANA lyase gene resulted in the change from inducible to constitutive production of the enzyme. The level of expression of the NANA lyase gene in E. coli(pNAL1) clones was two- to three-fold higher than that in the fully induced wild-type strains.
Sulfate Reduction Relative to Methane Production in High-Rate Anaerobic Digestion: Technical Aspects
Authors: Isa Zaid , Grusenmeyer Stéphane , Verstraete Willy
Published: January 2020

The effect of different substrates and different levels of sulfate and sulfide on methane production relative to sulfate reduction in high-rate anaerobic digestion was evaluated. Reactors could be acclimated so that sulfate up to a concentration of 5 g of sulfate S per liter did not significantly affect methanogenesis. Higher levels gave inhibition because of salt toxicity. Sulfate reduction was optimal at a relatively low level of sulfate, i.e., 0.5 g of sulfate S per liter, but was also not significantly affected by higher levels. Both acetoclastic and hydrogenotrophic methane-producing bacteria adapted to much higher levels of free H
2
S than the values reported in the literature (50% inhibition occurred only at free H
2
S levels of more than 1,000 mg/liter). High levels of free H
2
S affected the sulfate-reducing bacteria only slightly. Formate and acetate supported the sulfate-reducing bacteria very poorly. In the high-rate reactors studied, intensive H
2
S formation occurred only when H
2
gas or an H
2
precursor such as ethanol was supplied.
Ethylene Dibromide Mineralization in Soils under Aerobic Conditions
Authors: Pignatello Joseph J.
Published: January 2020

1,2-Dibromoethane (EDB), which is a groundwater contaminant in areas where it was once used as a soil fumigant, was shown to be degraded aerobically by microorganisms in two types of surface soils from an EDB-contaminated groundwater discharge area. At initial concentrations of 6 to 8 μg/liter, EDB was degraded in a few days to near or below the detection limit of 0.02 μg/liter. At 15 to 18 mg/liter, degradation was slower. Bromide ion release at the higher concentrations was 1.4 ± 0.3 and 2.1 ± 0.2 molar equivalents for the two soils. Experiments with [
14
C]EDB showed that EDB was converted to approximately equal amounts of CO
2
and apparent cellular carbon; only small amounts of added
14
C were not attributable to these products or unreacted EDB. These results are encouraging, because they indicate that groundwater bacteria may hasten the removal of EDB from contaminated aerobic groundwater supplies. This report also provides evidence for soil-mediated chemical transformations of EDB.
Attached and Free-Floating Bacterioplankton in Howe Sound, British Columbia, a Coastal Marine Fjord-Embayment
Authors: Albright L. J. , McCrae S. K. , May B. E.
Published: January 2020

Factors which influence the attachment of bacterioplankton to particles (including phytoplankton) were investigated by using (i) water samples removed from a coastal temperate fjord over an annual cycle and (ii) unialgal cultures of
Prorocentrum minimum, Dunaliella tertiolecta
, and
Skeletonema costatum
. Silt and salinity levels in this fjord seawater did not appear to influence bacterial attachment, but the percent attached bacteria was inversely related to both chlorophyll
a
concentrations and primary productivities. During periods of high primary productivities the percent attached bacteria was low, whereas during periods of low, increasing, and declining primary productivities the percent attached bacteria was high. A similar pattern of bacterial attachment was observed when the three phytoplankton were grown as batch cultures. The percent attached bacterial numbers increased upon the initiation of algal growth and after these cells stopped growing, but not while the algae were growing. We suggest that a major factor influencing the attachment of bacterioplankton is the physiological condition of their major nutrient source, the phytoplankton; mainly free-living bacteria are associated with growing phytoplankton, whereas a much greater proportion of the bacteria are attached among senescent phytoplankton populations.
Microbiological evaluation of the intraruminal in sacculus digestion technique
Authors: Meyer J H , Mackie R I
Published: January 2020

The influence of nature of the feed sample, feeding frequency and pore size on the influx of bacteria and protozoa into synthetic fiber bags suspended in the rumens of sheep fed different diets was studied. Counts of total culturable bacteria in bags with a pore size of 10 microns were less than 30% of the ruminal counts for animals that were fed the lucerne hay and high-roughage diets. The maximum count (62 and 82% of the ruminal count) for these specific diets was obtained by using bags with a pore size of 53 microns. Protozoal counts in bags with pore sizes of 30 and 53 microns were equal to or higher than the ruminal counts for the lucerne hay and high-roughage diets but less than half of the ruminal count for the low-roughage diet. An interaction between incubation time, feeding frequency of the host animals, and the microbial populations developing inside the bags was also demonstrated. The results clearly show that the microbial population inside the bag differed from that of the surrounding ruminal ingesta and that caution must be taken in interpreting results on feed evaluation and especially on rates of degradation when using the in sacculus technique. Factors influencing the influx of bacteria and protozoa into bags with different pore sizes and containing a variety of substrates are discussed together with suggestions for the use of this technique.
Sulfur regulation of heparinase and sulfatases in Flavobacterium heparinum
Authors: Cerbelaud E C , Conway L J , Galliher P M , Langer R S , Cooney C L
Published: January 2020

Sulfur regulation of heparinase synthesis and sulfatase synthesis was studied in Flavobacterium heparinum. Heparinase synthesis was strongly repressed by sulfate and L-cysteine, while the activity of this enzyme showed little or no inhibition by these compounds. Heparinase was synthesized in the absence of heparin when L-methionine was used as the sole sulfur source. The sulfatases produced by F. heparinum, which include the sulfatases involved in heparin catabolism, were also studied. At least some of the sulfatase activity was regulated by sulfur compounds in a manner similar to heparinase regulation. L-Cysteic acid and taurine were not suitable sulfur sources to support the growth of F. heparinum.
Assimilatory reduction of sulfate and sulfite by methanogenic bacteria
Authors: Daniels L , Belay N , Rajagopal B S
Published: January 2020

A variety of sulfur-containing compounds were investigated for use as medium reductants and sulfur sources for growth of four methanogenic bacteria. Sulfide (1 to 2 mM) served all methanogens investigated well. Methanococcus thermolithotrophicus and Methanobacterium thermoautotrophicum Marburg and delta H grew well with S0, SO3(2-), or thiosulfate as the sole sulfur source. Only Methanococcus thermolithotrophicus was able to grow with SO4(2-) as the sole sulfur source. 2-Mercaptoethanol at 20 mM was greatly inhibitory to growth of Methanococcus thermolithotrophicus on SO4(2-) or SO2(2-) and Methanobacterium thermoautotrophicum Marburg on SO3(2-) but not to growth of strain delta H on SO3(2-). Sulfite was metabolized during growth by Methanococcus thermolithotrophicus. Sulfide was produced in cultures of Methanococcus thermolithotrophicus growing on SO4(2-), SO3(2-), thiosulfate, and S0. Methanobacterium thermoautotrophicum Marburg was successfully grown in a 10-liter fermentor with S0, SO3(2-), or thiosulfate as the sole sulfur source.
Symbiotic Relationship of
Bacteroides cellulosolvens
and
Clostridium saccharolyticum
in Cellulose Fermentation
Authors: Murray William D.
Published: January 2020

In coculture,
Bacteroides cellulosolvens
and
Clostridium saccharolyticum
fermented 33% more cellulose than did
B. cellulosolvens
alone. Also, cellulose digestion continued at a maximum rate 48 h longer in coculture.
B. cellulosolvens
hydrolyzes cellulose and supplies
C. saccharolyticum
with sugars and a growth factor replaceable by yeast extract. Alone,
B. cellulosolvens
exhibited an early cessation of growth which was not due to nutrient depletion, low pH, or toxic accumulation of acetic acid, ethanol, lactic acid, H
2
, CO
2
, cellobiose, glucose, or xylose. However, a 1-h incubation of
B. cellulosolvens
spent-culture medium with
C. saacharolyticum
cells starved for growth factor allowed a resumption of
B. cellulosolvens
growth. The symbiotic relationship of this naturally occurring coculture is one of mutualism, in which the cellulolytic microbe supplies the saccharolytic microbe with nutrients, and in turn the saccharolytic microbe removes a secondary metabolite toxic to the primary microbe.
Biochemical Function and Ecological Significance of Novel Bacterial Lipids in Deep-Sea Procaryotes
Authors: DeLong Edward F. , Yayanos A. Aristides
Published: January 2020

The fatty acid composition of the membrane lipids in 11 deep-sea bacterial isolates was determined. The fatty acids observed were typical of marine vibrios except for the presence of large amounts of long-chain polyunsaturated fatty acids (PUFAs). These long-chain PUFAs were previously thought to be absent in procaryotes, with the notable exception of a single marine
Flexibacter
sp. In three barophilic strains tested at 2°C, there was a general increase in the relative amount of PUFAs as pressure was increased from a low growth pressure towards the optimal growth pressure. In
Vibrio marinus
MP-1, a psychrophilic strain, PUFAs were found to increase as a function of decreasing temperature at constant atmospheric pressure. These results suggest the involvement of PUFAs in the maintenance of optimal membrane fluidity and function over environmentally relevant temperatures and pressures. Furthermore, since these lipids are essential nutrients for higher taxa and are found in large amounts in the lipids of deep-sea vertebrates and invertebrates, an important, specific role for deep-sea bacteria in abyssal food webs is implicated.