bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship between Fungal Biomass Production and the Brightening of Hardwood Kraft Pulp by
Coriolus versicolor
Authors: Kirkpatrick Neil , Reid Ian D. , Ziomek Edmund , Ho Christopher , Paice Michael G.
Published: January 2020

The white-rot fungus
Coriolus versicolor
increased the brightness of hardwood kraft pulp by two mechanisms depending on the concentration of available nitrogen. In low-nitrogen conditions, the brightening process was a chemical effect mediated by the fungus, associated with the removal of residual lignin in the pulp; kappa number was used as an indicator of lignin concentration. A five-day treatment in low-nitrogen conditions increased the brightness of hardwood kraft pulp from 36.2 to 54.5%, with a corresponding decrease in kappa number from 12.0 to 8.5, equivalent to a reduction in the lignin concentration from ca. 2.0% (wt/wt) to ca. 1.4% (wt/wt). Under these conditions, we concluded that the brightening of the pulp was a secondary metabolic event initiated after the depletion of available nitrogen. This method of brightening has been described as bleaching or biobleaching. By contrast, in high-nitrogen conditions, the brightening was a physical effect associated with the dilution of the dark pulp fibers by the relatively high levels of brighter fungal mycelium produced. Since this method of brightening was not evidently associated with lignin removal, it cannot be described as bleaching. In pulp samples brightened in high-nitrogen conditions, as brightness increased, there was a corresponding increase in kappa number. This observation was explained by the consumption of potassium permanganate by the fungal mycelium, which interfered with kappa number determinations at high fungal biomass levels.
Cloning of two bacteriocin genes from a lactococcal bacteriocin plasmid
Authors: van Belkum M J , Hayema B J , Geis A , Kok J , Venema G
Published: January 2020

Lactococcus lactis subsp. cremoris 9B4 plasmid p9B4-6 (60 kilobases [kb]), which specifies bacteriocin production and immunity, was analyzed with restriction endonucleases, and fragments of this plasmid were cloned into shuttle vectors based on the broad-host-range plasmid pWVO1. Two regions on p9B4-6 were identified which specify inhibitory activity on L. lactis indicator strains: one that could be confined to a 1.8-kb ScaI-ClaI fragment with low antagonistic activity and a 15-kb XbaI-SalI fragment specifying high antagonistic activity. The inhibitory substances produced by these two clones were sensitive to proteolysis. A 4-kb HindIII fragment derived from the 15-kb fragment strongly hybridized with the 1.8-kb fragment. The antagonistic activity specified by the 4-kb fragment was somewhat reduced as compared with that of the 15-kb fragment. A 1.3-kb ScaI-HindIII subfragment of the 4-kb fragment contained both the immunity and bacteriocin genes. Inhibition studies showed that the two bacteriocins had different specificities.
Competition by
Bradyrhizobium
Strains for Nodulation of the Nonlegume
Parasponia andersonii
Authors: Trinick M. J. , Hadobas P. A.
Published: January 2020

Bradyrhizobium
strains isolated from the nonlegume
Parasponia
spp. formed a group of strains that were highly competitive for nodulation of
P. andersonii
when paired with strains isolated from legumes. Strains from legumes, including those of similar effectiveness to NGR231 and CP283, were not able to form nodules as single occupants on
P. andersonii
in the presence of
Parasponia
strains. However, NGR86, an isolate from
Macroptilium lathyroides
, jointly occupied one-third of the nodules formed with each of the three strains isolated from
Parasponia
spp. Time taken for nodules to appear may have influenced the outcome of competition, since CP283 and all isolates from legumes were slow to nodulate
P. andersonii
. Among the
Parasponia
strains, competitiveness for nodulation of
P. andersonii
was not associated with effectiveness of nitrogen fixation. The highly effective strain CP299 was a poor competitor when paired with the least effective strain NGR231. CP283 was the least competitive of the
Parasponia
strains but was still able to dominate nodules when paired with legume isolates. Dual occupancy was high, up to 67% when the inoculum contained CP299 and CP273. Both the Muc
+
and Muc
-
types of CP283 form a symbiosis of similar effectiveness and were similarly competitive at high inoculation densities, but the Muc
-
form was more competitive at low inoculum densities. Both forms frequently occupied the same nodule.
Bradyrhizobium
strains isolated from
Parasponia
spp. may have specific genetic information that favor their ability to competitively and effectively infect plants in the genus
Parasponia
(Ulmaceae) outside the Leguminosae.
Survival of chlorine-injured enterotoxigenic Escherichia coli in an in vitro water system
Authors: Walsh S M , Bissonnette G K
Published: January 2020

Survival of chlorine-injured and noninjured subpopulations of enterotoxigenic Escherichia coli was compared in KH2PO4-buffered water and chlorine-neutralized tap water. Injured cells were no less persistent than noninjured cells and did not exhibit limited survival as a consequence of chlorine injury. At high inoculum densities, some injured cells were able to repair, apparently owing to the accumulation of materials arising from the chlorination procedure.
Synthetic Medium for
Acetobacter xylinum
That Can Be Used for Isolation of Auxotrophic Mutants and Study of Cellulose Biosynthesis
Authors: Forng E. R. , Anderson S. M. , Cannon R. E.
Published: January 2020

Acetobacter xylinum
is a bacterium that can synthesize cellulose when grown in an undefined medium containing glucose. We developed a defined minimal medium for
A. xylinum
that contains 1% glucose, 0.1% NH
4
Cl, 0.115% citric acid, 0.33% Na
2
HPO
4
, 0.01% KCl, 0.025% MgSO
4
. 7H
2
O, and 7.5 mg of nicotinamide per liter which both allows cellulose synthesis and can be used to isolate a variety of auxotrophic mutants.
Novel Alterations in Plasmid DNA Associated with Aromatic Hydrocarbon Utilization by
Pseudomonas putida
R5-3
Authors: Carney Brian F. , Leary J. V.
Published: January 2020

Subcultures of
Pseudomonas putida
R5-3 altered their plasmid DNA content in specific ways depending on the particular aromatic hydrocarbon utilized as the sole carbon source. Two indigenous plasmids, 115 and 95 kilobases (kb) in size, were observed in R5-3A, which was derived from R5-3 by growth on minimal medium containing
p
-methylbenzoate as the sole carbon source. When R5-3A was transferred to medium containing
m
-xylene or toluene, derivative strains were obtained in which the 95-kb plasmid was lost and a new plasmid of 50 or 60 kb appeared. Reversion to the original plasmid profile of R5-3A was observed when xylene- or toluene-grown cells were returned to medium containing
p
-methylbenzoate. Restriction enzyme analysis and Southern blot hybridizations of total plasmid DNA indicated deletions and rearrangements of DNA restriction fragments in the derivatives maintained on
m
-xylene and toluene when compared with the original R5-3A. In the derivatives which retrieved the original plasmid profile, the restriction enzyme fragment pattern was identical to that in the original R5-3A, in that the fragments which were missing after growth on
m
-xylene or toluene were again present. Southern blot hybridizations revealed that part of the plasmid DNA lost from the original plasmid profile was integrated into the chromosomal DNA of xylene-grown R5-3B and that these plasmid fragments were associated with aromatic hydrocarbon metabolism. Hybridization with pathway-specific DNA fragments from the TOL plasmid pWWO indicated that this 95-kb plasmid contains DNA homologous to the
meta
-fission pathway genes.
Kinetic Analysis of Protein Degradation by a Freshwater Wetland Sediment Community
Authors: Cunningham H. W. , Wetzel Robert G.
Published: January 2020

The mineralization of proteins by the sediment microflora of a freshwater wetland conformed to a kinetic model developed for polymer degradation. The maximum velocity of protein mineralization ranged from 2,078 to 147 nmol of protein cm
−3
h
−1
from May to October. The turnover time of protein was 13 to 69 h. A statistical comparison of the kinetic parameters by the standard error of the estimate demonstrated that protein degradation exhibited significant random fluctuations throughout the growing season. These fluctuations were related to changes in the concentration of readily degradable protein as estimated by
K

t

. Utilization of amino acids was 9 to 57 times greater than the utilization of protein, and the turnover time for amino acids was 1.6 to 3.7 h.
Specific Dot-Immunobinding Assay for Detection and Enumeration of
Thiobacillus ferrooxidans
Authors: Arredondo Renato , Jerez Carlos A.
Published: January 2020

A specific and very sensitive dot-immunobinding assay for the detection and enumeration of the bioleaching microorganism
Thiobacillus ferrooxidans
was developed. Nitrocellulose spotted with samples was incubated with polyclonal antisera against whole
T. ferrooxidans
cells and then in
125
I-labeled protein A or
125
I-labeled goat antirabbit immunoglobulin G; incubation was followed by autoradiography. Since a minimum of 10
3
cells per dot could be detected, the method offers the possibility of simultaneous processing of numerous samples in a short time to monitor the levels of
T. ferrooxidans
in bioleaching operations.
Vero cell assay for rapid detection of Clostridium perfringens enterotoxin
Authors: Mahony D E , Gilliatt E , Dawson S , Stockdale E , Lee S H
Published: January 2020

A rapid assay which measured the biological activity of Clostridium perfringens enterotoxin was developed. The method involved the rapid killing of Vero cells by enterotoxin produced by C. perfringens grown in Duncan and Strong sporulation medium. Serial dilutions of toxin were added to Vero cells either in suspension or grown as monolayers in wells of a 96-well cell tissue culture cluster plate. Vital staining of Vero cells with neutral red, followed by extraction of the dye, allowed toxin levels to be determined either visually or by optical density measurements with a micro-ELISA M580 computer program. The toxin produced was confirmed as different from the Vero toxin of Escherichia coli and the alpha and theta toxins of C. perfringens.
Trichothecenes accumulated in liquid culture of a mutant of Fusarium sporotrichioides NRRL 3299
Authors: Plattner R D , Tjarks L W , Beremand M N
Published: January 2020

A UV-generated mutant of Fusarium sporotrichioides NRRL 3299 was altered in its ability to biosynthesize T-2 toxin, as shown by a rapid screen with monoclonal antibodies to T-2. This stable mutant accumulated two trichothecenes that were not observed in liquid cultures of the parent strain. The two compounds were identified as 3,15-diol 12,13-epoxytrichothec-9-ene and 3,15-diol 12,13-epoxytrichothec-9-ene 3-acetate on the basis of their nuclear magnetic resonance and mass spectra. This is the first report of either of these two compounds as secondary metabolites of F. sporotrichioides and of a trichothecene acetylated at C-3 by this species.
Detection of Acinetobacter spp. in rural drinking water supplies
Authors: Bifulco J M , Shirey J J , Bissonnette G K
Published: January 2020

A bacteriological survey was conducted of untreated, individual groundwater supplies in Preston County, W.Va. Nearly 60% of the water supplies contained total coliforms in excess of the U.S. Environmental Protection Agency maximum contaminant level of 1 CFU/100 ml. Approximately one-third of the water systems contained fecal coliforms and/or fecal streptococci. Acinetobacter spp. were detected in 38% of the groundwater supplies at an arithmetic mean density of 8 CFU/100 ml and were present in 16% of the water supplies in the absence of total coliforms, posing some concern about the usefulness of total coliforms as indicators of the presence of this opportunistic pathogen. Slime production, a virulence factor for A. calcoaceticus, was not significantly different between well water isolates and clinical strains, suggesting some degree of pathogenic potential for strains isolated from groundwater. In addition, several Acinetobacter isolates were able to interfere with sheen production by some coliform bacteria on M-Endo medium, adding further to the possible significance of Acinetobacter spp. in groundwater supplies.
Colonization of a Submersed Aquatic Plant, Eurasian Water Milfoil (
Myriophyllum spicatum
), by Fungi under Controlled Conditions
Authors: Smith Craig S. , Chand Tara , Harris Robin F. , Andrews John H.
Published: January 2020

A laboratory assay to assess colonization of a submersed aquatic plant, Eurasian water milfoil (
Myriophyllum spicatum
), by fungi was developed and used to evaluate the colonization potential of
Colletotrichum gloeosporioides, Acremonium curvulum, Cladosporium herbarum, Aureobasidium pullulans
, a
Paecilomyces
sp., and an unidentified sterile, septate fungus. Stem segments of plants were first immersed in suspensions of fungal propagules for 24 h and then washed to remove all but the tightly attached component of the population. Inoculation was followed by two growth cycles of 3 days each. At the start of each cycle, washed plants were transferred to a mineral salts medium to provide an opportunity for the attached fungal populations to grow. After each growth period, plants were again washed, and fungal populations in the medium (nonattached), loosely attached and tightly attached to the plant, and within the plant (endophytic) were assayed by dilution plating. The fungi differed in the extent to which they attached to water milfoil and in their ability to grow in association with it. There were relatively few significant differences among the tightly attached fungal populations after 24 h, but growth of the better colonizers led to a greater number of significant differences after 4 and 7 days. In addition, the better colonizers showed sustained regrowth of loosely and nonattached fungal propagules in the face of intermittent removal by washing. A milfoil pathogen,
C. gloeosporioides
, was the only endophytic colonizer; it was also among the best epiphytic colonizers but was not demonstrably better than
A. curvulum
, a fungus commonly found as an epiphyte on watermilfoil. The yeastlike hyphomycete
Aureobasidium pullulans
was the only fungus that consistently failed to establish an increasing population on the plant.
Glucose metabolism and NADH recycling by Treponema hyodysenteriae, the agent of swine dysentery
Authors: Stanton T B
Published: January 2020

Glucose metabolism and the mechanisms of NADH oxidation by Treponema hyodysenteriae were studied. Under an N2 atmosphere, washed cell suspensions of the spirochete consumed glucose and produced acetate, butyrate, H2, and CO2. Approximately twice as much H2 as CO2 was produced. Determinations of radioactivity in products of [14C]glucose and [14C]pyruvate metabolism and analyses of enzyme activities in cell lysates revealed that glucose was catabolized to pyruvate via the Embden-Meyerhof-Parnas pathway. The results of pyruvate exchange reactions with NaH14CO3 and Na14COOH demonstrated that pyruvate was converted to acetyl coenzyme A (acetyl-CoA), H2, and CO2 by a clostridium-type phosphoroclastic mechanism. NADH:ferredoxin oxidoreductase and hydrogenase activities were present in cell lysates and produced H2 from NADH oxidation. Phosphotransacetylase and acetate kinase catalyzed the formation of acetate from acetyl-CoA. Butyrate was formed from acetyl-CoA via a pathway that involved 3-hydroxybutyryl-coenzyme A (CoA) dehydrogenase, butyryl-CoA dehydrogenase, and butyryl-CoA transferase. T. hyodysenteriae cell suspensions generated less H2 and butyrate under 10% O2-90% N2 than under 100% N2. Cell lysates contained NADH oxidase, NADH peroxidase, and superoxide dismutase activities. These findings indicated there are three major mechanisms that T. hyodysenteriae cells use to recycle NADH generated from the Embden-Meyerhof-Parnas pathway--enzymes in the pathway from acetyl-CoA to butyrate, NADH:ferredoxin oxidoreductase, and NADH oxidase. Versatility in methods of NADH oxidation and an ability to metabolize oxygen could benefit T. hyodysenteriae cells in the colonization of tissues of the swine large bowel.
Hemagglutination and intestinal adherence properties of clinical and environmental isolates of non-O1 Vibrio cholerae
Authors: Datta-Roy K , Dasgupta C , Ghose A C
Published: January 2020

Hemagglutination and intestinal adherence properties of non-O1 Vibrio cholerae were studied in vitro. No definite correlation between the cell-associated hemagglutinin titers and the intestinal adhesion indices was noted. Sugar- and glycoprotein-mediated inhibition data also indicated differences between the hemagglutination and adherence processes in respect to the receptor structures. Intestinal adherence of most V. cholerae strains could be inhibited to various extents by N-acetyl D-glucosamine. This observation provides a likely explanation for the ecological behavior of these organisms, which are known to associate themselves with chitinous (chitin:homopolymer of N-acetyl D-glucosamine) surfaces of zooplankton. The absence of any significant difference between the intestinal adherence indices of clinical and environmental isolates suggests that intestinal adhesion may be an essential but not sufficient prerequisite for colonization by and subsequent expression of pathogenicity of these microorganisms.
New pathway for the biodegradation of indole in Aspergillus niger
Authors: Kamath A V , Vaidyanathan C S
Published: January 2020

Indole and its derivatives form a class of toxic recalcitrant environmental pollutants. The growth of Aspergillus niger was inhibited by very low concentrations (0.005 to 0.02%) of indole, even when 125- to 500-fold excess glucose was present in the medium. When 0.02% indole was added, the fungus showed a lag phase for about 30 h and the uptake of glucose was inhibited. Indole was metabolized by a new pathway via indoxyl (3-hydroxyindole), N-formylanthranilic acid, anthranilic acid, 2,3-dihydroxybenzoic acid, and catechol, which was further degraded by ortho cleavage. The enzymes N-formylanthranilate deformylase, anthranilate hydroxylase, 2,3-dihydroxybenzoate decarboxylase, and catechol dioxygenase were induced by indole as early as after 5 h of growth, and their activities were demonstrated in a cell-free system.
Differential effects of sodium on hydrogen- and glucose-dependent growth of the acetogenic bacterium Acetogenium kivui
Authors: Yang H C , Drake H L
Published: January 2020

Acetogenium kivui could not be revived or maintained in a sodium-deficient medium (0.2 mM sodium) under H2-dependent conditions, and neither lithium nor potassium replaced the sodium requirement of H2-cultivated cells. Conversely, the revival and maintenance of glucose-cultivated cells did not display a dependency on supplemental sodium. In the absence of growth, formate became a major end product in both sodium-deficient and metabolically impaired H2-grown cultures of A. kivui. Harmaline, a putative inhibitor of Na+/H+ antiporters, uncoupled acetogenesis from H2-dependent growth but was less effective when growth was at the expense of glucose. Significantly, carbon monoxide (CO) stimulated H2-dependent growth of A. kivui but inhibited glucose-dependent growth. Collectively, these findings demonstrate that sodium plays a critical role in the H2-dependent bioenergetics of A. kivui and indicate that autotrophic and heterotrophic cells may utilize dissimilar mechanisms of energy conservation. In contrast to the growth of A. kivui, supplemental sodium was not required for the glucose-, H2-, and CO-dependent growth of Clostridium thermoaceticum.
Possible mechanism of mannose inhibition of sucrose-supported growth in N2-fixing Azotobacter vinelandii
Authors: Wong T Y
Published: January 2020

When mannose was added to a sucrose-supported culture of Azotobacter vinelandii under N2-fixing conditions, cell growth was inhibited. The degree of inhibition was proportional to the amount of mannose and to the aeration rate (T.-Y. Wong, Appl. Environ. Microbiol. 54:473-475, 1988). In this report, we demonstrate that once inside the cell, mannose was phosphorylated to mannose 6-phosphate. It was then isomerized to fructose 6-phosphate and to glucose 6-phosphate. Mannose inhibited sucrose uptake noncompetitively. The decrease in sucrose uptake after mannose addition coincided with a lower rate of respiration and a decrease in nitrogenase activity. The decrease in sucrose uptake and in the ATP pool may decrease the electron flow and reduce protection of the nitrogenase from O2. Cells became very sensitive to O2, and therefore, cell growth was inhibited under high aeration conditions.
Mathematical Model of Plasmid Transfer between Strains of Streptomycetes in Soil Microcosms
Authors: Clewlow L. J. , Cresswell N. , Wellington E. M. H.
Published: January 2020

A mathematical model was developed and used to simulate the long-term dynamics of growth and plasmid transfer in nutrient-limited soil microcosms of
Streptomyces lividans
TK24 carrying chromosomal resistance to streptomycin,
S. lividans
1326; and
S. violaceolatus
ISP5438. Donor, recipient, and transconjugant survival was modelled by an extension to the Verhulst logistic equation which takes account of nutrient limitation, and plasmid transfer was modelled by a mass action model. Rate parameters were derived from experimental data on the early stages of the development of sterile systems. The model predicted donor, recipient, and transconjugant populations in 2.4-h (0.1-day) steps and was tested against the long-term behavior of the experimental sterile systems and independent experimental data on nonsterile systems. Bacteria were periodically enumerated onto selective media over a 20-day period. The effects of long-term nutrient-moisture depletion were correctly predicted.
Reductive dehalogenation of carbon tetrachloride by Escherichia coli K-12
Authors: Criddle C S , DeWitt J T , McCarty P L
Published: January 2020

The formation of radicals from carbon tetrachloride (CT) is often invoked to explain the product distribution resulting from its transformation. Radicals formed by reduction of CT presumably react with constituents of the surrounding milieu to give the observed product distribution. The patterns of transformation observed in this work were consistent with such a hypothesis. In cultures of Escherichia coli K-12, the pathways and rates of CT transformation were dependent on the electron acceptor condition of the media. Use of oxygen and nitrate as electron acceptors generally prevented CT metabolism. At low oxygen levels (approximately 1%), however, transformation of [14C]CT to 14CO2 and attachment to cell material did occur, in accord with reports of CT fate in mammalian cell cultures. Under fumarate-respiring conditions, [14C]CT was recovered as 14CO2, chloroform, and a nonvolatile fraction. In contrast, fermenting conditions resulted in more chloroform, more cell-bound 14C, and almost no 14CO2. Rates of transformation of CT were faster under fermenting conditions than under fumarate-respiring conditions. Transformation rates also decreased over time, suggesting the gradual exhaustion of transformation activity. This loss was modeled with a simple exponential decay term.
Dimethyl Sulfide Production from Dimethylsulfoniopropionate in Coastal Seawater Samples and Bacterial Cultures
Authors: Kiene Ronald P.
Published: January 2020

Dimethyl sulfide (DMS) was produced immediately after the addition of 0.1 to 2 μM β-dimethylsulfonio-propionate (DMSP) to coastal seawater samples. Azide had little effect on the initial rate of DMS production from 0.5 μM added DMSP, but decreased the rate of production after 6 h. Filtration of water samples through membrane filters (pore size, 0.2 μm) greatly reduced DMS production for approximately 10 h, after which time DMS production resumed at a high rate. Autoclaving completely eliminated the production of DMS. The antibiotics chloramphenicol, tetracycline, kanamycin, and vancomycin all had little effect on the accumulation of DMS over the first few hours of incubation, but produced significant inhibition thereafter. The effects of individual antibiotics were additive. Chloroform over a range of concentrations (0.25 to 1.25 mM) had no effects on DMS production. Similarly, organic amendments, including acrylate, glucose, protein, and starch, did not affect DMS accumulation from DMSP. Acrylate, a product of the enzymatic cleavage of DMSP, was metabolized in seawater samples, and two strains of bacteria were isolated with this compound as the growth substrate. These bacteria produced DMS from DMSP. The sensitivity to inhibitors with respect to growth and DMSP-lyase activity varied from strain to strain. These results illustrate the significant potential for microbial conversion of dissolved DMSP to DMS in coastal seawater.
Cloning of a gene from Pseudomonas sp. strain PG2982 conferring increased glyphosate resistance
Authors: Fitzgibbon J E , Braymer H D
Published: January 2020

A plasmid carrying a 2.4-kilobase-pair fragment of DNA from Pseudomonas sp. strain PG2982 has been isolated which was able to increase the glyphosate resistance of Escherichia coli cells. The increase in resistance was dependent on the presence of a plasmid-encoded protein with a molecular weight of approximately 33,000, the product of a translational fusion between a gene on the vector, pACYC184, and the insert DNA. An overlapping region of the PG2982 chromosome carrying the entire gene (designated igrA) was cloned, and a plasmid (pPG18) carrying the gene was also able to increase glyphosate resistance in E. coli. A protein with a molecular weight of approximately 40,000 was encoded by the PG2982 DNA contained in pPG18. This plasmid was not able to complement a mutation in the gene for 5-enolpyruvylshikimate-3-phosphate synthase (aroA) in E. coli, and modification of glyphosate by E. coli cells containing the plasmid could not be demonstrated. The nucleotide sequence of the PG2982 DNA contained an open reading frame able to encode a protein with a calculated molecular weight of 39,396.
Protease-mediated degradation of lignin peroxidase in liquid cultures of Phanerochaete chrysosporium
Authors: Dosoretz C G , Dass S B , Reddy C A , Grethlein H E
Published: January 2020

The decline of lignin peroxidase (LiP) activity observed after day 6 in cultures of Phanerochaete chrysosporium was found to be correlated with the appearance of idiophasic extracellular protease activity. Daily addition of glucose started on day 6 resulted in low protease levels and in turn in stable LiP levels. Addition of cycloheximide to day 6 cultures resulted in virtually no change of LiP activity and extracellular protein and negligible levels of protease activity, indicating that this protease is synthesized de novo. LiP activity was found to be stable upon removal of the fungal pellets on day 6 and incubation of the extracellular fluid alone. An almost complete disappearance of LiP activity and LiP proteins and high levels of protease activity were observed upon incubation of 6-day extracellular fluid in the presence of fungal pellets. Moreover, incubation of crude or purified LiP isoenzymes with protease-rich extracellular fluid of day 11 or 11-day cell extracts resulted in a marked loss of activity. In contrast, incubation of crude LiP with boiled and clarified extracellular fluid of day 11 cultures resulted in virtually no loss of activity. These results indicate that protease-mediated degradation of LiP proteins is a major cause for the decay of LiP activity during late secondary metabolism in cultures of P. chrysosporium.
Regulation of protease production in Clostridium sporogenes
Authors: Allison C , Macfarlane G T
Published: January 2020

The physiological and nutritional factors that regulate protease synthesis in Clostridium sporogenes C25 were studied in batch and continuous cultures. Formation of extracellular proteases occurred at the end of active growth and during the stationary phase in batch cultures. Protease production was inversely related to growth rate in glucose-excess and glucose-limited chemostats over the range D = 0.05 to 0.70 h-1. In pulse experiments, glucose, ammonia, phosphate, and some amino acids (tryptophan, proline, tyrosine, and isoleucine) strongly repressed protease synthesis. This repression was not relieved by addition of 4 mM cyclic AMP, cyclic GMP, or dibutyryl cyclic AMP. Protease formation was markedly inhibited by 4 mM ATP and ADP, but GTP and GDP had little effect on the process. It is concluded that protease production by C. sporogenes is strongly influenced by the amount of energy available to the cells, with the highest levels of protease synthesis occurring under energy-limiting conditions.
Loss of Nitrous Oxide Reductase in
Pseudomonas aeruginosa
Cultured under N
2
O as Determined by Rocket Immunoelectrophoresis
Authors: SooHoo Carlton K. , Hollocher Thomas C.
Published: January 2020

The mass ratio of nitrous oxide reductase to total protein in the soluble protein fraction of
Pseudomonas aeruginosa
P2 was highest in cells grown on nitrate, decreased in cells grown on N
2
O following the exhaustion of the initial charge of nitrate, and was nearly zero in cells exposed solely to N
2
O.
Flow cytometry sorting of viable bacteria and yeasts according to beta-galactosidase activity
Authors: Nir R , Yisraeli Y , Lamed R , Sahar E
Published: January 2020

We describe a novel method for quantitative measurement of beta-galactosidase (beta-gal) levels in bacteria and yeasts by using flow cytometry, a method which allows viable microbial cells to be sorted on the basis of the expressed activity and to be recultivated. The method is based on encapsulating single cells in agarose microbeads 20 to 30 microns in diameter and analyzing the beta-gal activity of the colonies that develop (containing several hundred cells) by using the fluorogenic substrate fluorescein-di-beta-D-galactopyranoside (FDG). Three strains of Escherichia coli, containing different levels of beta-gal, served as a model system. A high degree of correlation was found between the average fluorescence measured per bead and the level of the enzyme in extracts of the respective strain. Although the use of FDG necessitates cell permeabilization, conditions were found under which a small part of each colony remained viable, yet most of the enzyme was exposed to the substrate. This allowed sorting of microcolonies and plating with close to 100% efficiency. The potential of the technique was demonstrated by selecting beta-gal-positive cells from an artificial mixture of beta-gal-positive and beta-gal-negative E. coli strains.
Microbial degradation of quinoline and methylquinolines
Authors: Aislabie J , Bej A K , Hurst H , Rothenburger S , Atlas R M
Published: January 2020

Several bacterial cultures were isolated that are able to degrade quinoline and to transform or to degrade methylquinolines. The degradation of quinoline by strains of Pseudomonas aeruginosa QP and P. putida QP produced hydroxyquinolines, a transient pink compound, and other undetermined products. The quinoline-degrading strains of P. aeruginosa QP and P. putida QP hydroxylated a limited number of methylquinolines but could not degrade them, nor could they transform 2-methylquinoline, isoquinoline, or pyridine. Another pseudomonad, Pseudomonas sp. strain MQP, was isolated that could degrade 2-methylquinoline. P. aeruginosa QP was able to degrade or to transform quinoline and a few methylquinolines in a complex heterocyclic nitrogen-containing fraction of a shale oil. All of the quinoline- and methylquinoline-degrading strains have multiple plasmids including a common 250-kilobase plasmid. The 225-, 250-, and 320-kilobase plasmids of the P. aeruginosa QP strain all contained genes involved in quinoline metabolism.
Effects of environmental conditions on xylose fermentation by recombinant Escherichia coli
Authors: Ohta K , Alterthum F , Ingram L O
Published: January 2020

In batch fermentations, optimal conversion of xylose to ethanol by recombinant Escherichia coli was obtained under the following conditions: 30 to 37 degrees C, pH 6.4 to 6.8, 0.1 to 0.2 M potassium phosphate buffer, and xylose concentrations of 8% or less. A yield of 39.2 g of ethanol per liter (4.9% ethanol by volume) was observed with 80 g of xylose per liter, equivalent to 96% of the maximum theoretical yield. Maximal volumetric productivity was 0.7 g of ethanol per liter per h in batch fermentations and 30 g of ethanol per liter per h in concentrated cell suspensions (analogous to cell recycling).
Diel Nitrogen Fixation by Cyanobacterial Surface Blooms in Sanctuary Lake, Pennsylvania
Authors: Storch Thomas A. , Saunders George W. , Ostrofsky Milton L.
Published: January 2020

Diel nitrogen fixation studies were conducted with assemblages of cyanobacteria sampled from surface blooms on Sanctuary Lake, Pa. The studies were conducted between July and September of 1982 to 1985 by using the acetylene reduction technique. Assemblages with the lowest cell concentrations (0.9 � 10
9
to 1.0 � 10
9
cells per liter) exhibited nitrogen fixation activity throughout the day, with maximum fixation rates occurring in mid to late afternoon; fixation proceeded throughout the night at rates equivalent to 23 to 28% of the afternoon maximum. In studies conducted with the highest cell concentrations (3.7 � 10
9
to 6.7 � 10
9
cells per liter), fixation rates reached maximum values in mid to late morning. The rates declined rapidly throughout the midday period and subsequently ceased from late afternoon until sunrise on the following day. The afternoon decline and cessation of fixation exhibited by high cell concentrations correlated with photosynthetically induced low total CO
2
and supersaturating O
2
concentrations. The midday decline could be prevented and partially reversed by experimentally lowering O
2
and increasing total CO
2
concentrations. Under experimental conditions which simultaneously prevented supersaturating O
2
concentrations and maintained high total CO
2
availability, nitrogen fixation continued throughout the solar day, with maximum rates occurring at midday. These observations indicate that temporal changes in photosynthetic activity may affect diel fluctuations in nitrogen fixation.
Absence of trichothecenes in toxigenic isolates of Fusarium moniliforme
Authors: Mirocha C J , Abbas H K , Vesonder R F
Published: January 2020

Thirty-four isolates of Fusarium moniliforme were obtained from cereal grains collected in various parts of the world. The isolates were grown on rice and tested as a diet for toxicity to rats. Of these isolates, 53% caused death, 12% caused congestion and hemorrhage of the stomach and intestine as well as hematuria, 21% caused diarrhea, 38% caused weight loss, and 9% were nontoxic. The cultures were tested to T-2, HT-2, neosolaniol, acetyl-T-2, T-2-tetraol, iso-T-2, diacetoxyscirpenol, monoacetoxyscirpenol, deoxynivalenol, nivalenol, fusarenone-X, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, zearalenone, moniliformin, fusarochromanone, fusarin-C, and wortmannin; all were negative. In addition, F. moniliforme NRRL A25820 was grown on corn and banana fruit as solid substrates as well as on a defined liquid medium; none of the above toxins were found. When F. moniliforme NRRL A25820 was incorporated into a rat diet, no toxicity was noted. Twenty-eight additional isolates of F. moniliforme, isolated from feed associated with equine leukoencephalomalacia, were grown on cracked corn for 2 weeks. The cultures were negative when tested for deoxynivalenol, 15-acetyldeoxynivalenol, diacetoxyscirpenol, monoacetoxyscirpenol, nivalenol, and fusarenone X. Seventy-five percent of the isolates were toxic to ducklings, indicating the presence of a toxin other than trichothecenes. Our results support the conclusion that F. moniliforme does not produce trichothecenes.
Biotransformation of substituted benzoates to the corresponding cis-diols by an engineered strain of Pseudomonas oleovorans producing the TOL plasmid-specified enzyme toluate-1,2-dioxygenase
Authors: Wubbolts M G , Timmis K N
Published: January 2020

The conversion of substituted benzoates into 1,2-cis-dihydroxycyclohexa-3,5-diene carboxylic acids (cis-diols) was effected by using Escherichia coli and Pseudomonas recombinants carrying the xylXYZ genes originating from the Pseudomonas putida mt-2 TOL plasmid, thus producing toluate-1,2-dioxygenase. Pseudomonas oleovorans GPo12 recombinants readily produced meta- and para-substituted cis-diols, but were limited in their oxidation of ortho-substituted substrates.
Monoclonal antibody to type F Clostridium botulinum toxin
Authors: Ferreira J L , Hamdy M K , McCay S G , Zapatka F A
Published: January 2020

Hybridomas synthesizing monoclonal antibodies (MAbs) against type F Clostridium botulinum toxin were developed. MAb from one stable hybridoma, hybridoma 223, consisted of kappa light chains and an immunoglobulin G subclass 2a heavy chain. This MAb was used in a double-sandwich enzyme-linked immunosorbent assay to detect type F toxin in foods, culture fluids, and purified toxin preparations. The sensitivity of the double-sandwich enzyme-linked immunosorbent assay was approximately 10 mouse lethal doses of toxin per ml of toxic fluid.
Isolation of Candida albicans and halophilic Vibrio spp. from aquatic birds in Connecticut and Florida
Authors: Buck J D
Published: January 2020

Halophilic vibrios were recovered from feces of six types of aquatic birds (gulls, pelicans, Canada geese, swans, egrets, cormorants) from Connecticut and/or Florida shorelines. Candida albicans was isolated from gulls and Canada geese in Connecticut and from gulls and cormorants in Florida.
Cloning, sequence analysis, and expression of genes encoding xylan-degrading enzymes from the thermophile "Caldocellum saccharolyticum"
Authors: Lüthi E , Love D R , McAnulty J , Wallace C , Caughey P A , Saul D , Bergquist P L
Published: January 2020

A lambda recombinant bacteriophage coding for xylanase and beta-xylosidase activity has been isolated from a genomic library of the extremely thermophilic anaerobe "Caldocellum saccharolyticum." Partial Sau3AI fragments of the lambda recombinant DNA were ligated into pBR322. A recombinant plasmid with an insertion of ca. 7 kilobases of thermophilic DNA expressing both enzymatic activities was isolated. The location of the genes has been established by analyzing deletion derivatives, and the DNA sequence of 6.067 kilobases of the insert has been determined. Five open reading frames (ORFs) were found, one of which (ORF1; Mr 40,455) appears to code for a xylanase (XynA) which also acts on o-nitrophenyl-beta-D-xylopyranoside. Another, ORF5 (Mr 56,365), codes for a beta-xylosidase (XynB). The xynA gene product shows significant homology with the xylanases from the alkalophilic Bacillus sp. strain C125 and Clostridium thermocellum.
Transformation of Dibenzo-
p
-Dioxin by
Pseudomonas
sp. Strain HH69
Authors: Harms Hauke , Wittich Rolf-Michael , Sinnwell Volker , Meyer Holger , Fortnagel Peter , Francke Wittko
Published: January 2020

Dibenzo-
p
-dioxin was oxidatively cleaved by the dibenzofuran-degrading bacterium
Pseudomonas
sp. strain HH69 to produce minor amounts of 1-hydroxydibenzo-
p
-dioxin and catechol, while a 2-phenoxy derivative of muconic acid was formed as the major product. Upon acidic methylation, the latter yielded the dimethylester of
cis, trans
-2-(2-hydroxyphenoxy)-muconic acid.
Adhesion of an Amylolytic
Arthrobacter
sp. to Starch-Containing Plastic Films
Authors: Imam Syed H. , Gould J. Michael
Published: January 2020

Cells of the amylolytic bacterium KB-1 (thought to be an
Arthrobacter
sp.) adhered (∼70%) to the surface of plastic films composed of starch-poly (methylacrylate) graft copolymer (starch-PMA), but did not adhere (<10%) to films composed of polymethylacrylate (PMA), polyethylene (PE), carboxymethyl cellulose, or a mixture of PE plus poly (ethylene-coacrylic acid) (EAA), starch plus PE, or starch plus PE and EAA. About 30% of the cells adhered to gelatinized insoluble starch. Dithiothreitol (5 mM), EDTA (5 mM), and soluble starch (1%, wt/vol) had little effect on the adhesion of KB-1 cells to starch-PMA films. However, glutaraldehyde-fixed cells, azide-treated cells, and heat-killed cells did not bind to starch-PMA plastic, suggesting that the observed adhesion required cell viability. Culture supernatant from 5-day-old KB-1 cultures contained a proteolytic enzyme that inhibited cell adhesion to starch-PMA plastics. Trypsin-treated KB-1 cells also lost their ability to bind to starch-PMA plastic. When washed free of trypsin and suspended in fresh medium, trypsin-treated bacteria were able to recover adhesion activity in the absence, but not in the presence, of the protein synthesis inhibitor chloramphenicol. These results suggested that adhesion of KB-1 to starch-PMA plastic may be mediated by a cell surface protein. Although KB-1 bacteria bound to starch-PMA plastic, they did not appear to degrade starch in these films. Evidence of starch degradation was observed for starch-PE-EAA plastics, where <10% of the bacteria was bound, suggesting that cell adhesion may not be a prerequisite for degradation of some starch-containing plastics.
Batch Tests To Determine Activity Distribution and Kinetic Parameters for Acetate Utilization in Expanded-Bed Anaerobic Reactors
Authors: Fox Peter , Suidan Makram T.
Published: January 2020

Batch tests to measure maximum acetate utilization rates were used to determine the distribution of acetate utilizers in expanded-bed sand and expanded-bed granular activated carbon (GAC) reactors. The reactors were fed a mixture of acetate and 3-ethylphenol, and they contained the same predominant aceticlastic methanogen,
Methanothrix
sp. Batch tests were performed both on the entire reactor contents and with media removed from the reactors. Results indicated that activity was evenly distributed within the GAC reactors, whereas in the sand reactor a sludge blanket on top of the sand bed contained approximately 50% of the activity. The Monod half-velocity constant (
K

s

) for the acetate-utilizing methanogens in two expanded-bed GAC reactors was searched for by combining steady-state results with batch test data. All parameters necessary to develop a model with Monod kinetics were experimentally determined except for
K

s

. However,
K

s

was a function of the effluent 3-ethylphenol concentration, and batch test results demonstrated that maximum acetate utilization rates were not a function of the effluent 3-ethylphenol concentration. Addition of a competitive inhibition term into the Monod expression predicted the dependence of
K

s

on the effluent 3-ethylphenol concentration. A two-parameter search determined a
K

s

of 8.99 mg of acetate per liter and a
K

i

of 2.41 mg of 3-ethylphenol per liter. Model predictions were in agreement with experimental observations for all effluent 3-ethylphenol concentrations. Batch tests measured the activity for a specific substrate and determined the distribution of activity in the reactor. The use of steady-state data in conjunction with batch test results reduced the number of unknown kinetic parameters and thereby reduced the uncertainty in the results and the assumptions made.
Formation of deglycosylated alpha-L-fucosidase by endo-beta-N-acetylglucosaminidase in Fusarium oxysporum
Authors: Tsuji Y , Yamamoto K , Tochikura T
Published: January 2020

Two forms of alpha-L-fucosidase, deglycosylated and glycosylated, were found in the fucose-inducing culture broth of Fusarium oxysporum. Endo-beta-N-acetylglucosaminidase was also found in the same culture broth. The deglycosylated alpha-L-fucosidase was purified from the culture broth to homogeneity on polyacrylamide disc gel electrophoresis and analytical ultracentrifugation. Purified deglycosylated alpha-L-fucosidase was compared in chemical composition and immunological homology with glycosylated alpha-L-fucosidase which had been reported previously (K. Yamamoto, Y. Tsuji, H. Kumagai, and T. Tochikura, Agric. Biol. Chem. 50: 1689, 1986). Both enzymes had nearly the same amino acid compositions and were immunologically identical. Glycosylated alpha-L-fucosidase had mannose, galactose, and N-acetylglucosamine residues. In contrast, the deglycosylated enzyme had only N-acetylglucosamine residues. These results suggest that the deglycosylated alpha-L-fucosidase is formed by the release of sugar chains from the glycosylated form by Fusarium endo-beta-N-acetylglucosaminidase. Furthermore, various enzymatic properties were compared: the two alpha-L-fucosidases were found to exhibit similar catalytic activities and thermal stability profiles. The deglycosylated enzyme, however, was slightly unstable in the acidic pH range compared with the glycosylated enzyme.
Involvement of a Collar Structure in Polar Growth and Cell Division of Strain DCB-1
Authors: Mohn William W. , Linkfield Timothy G. , Pankratz H. Stuart , Tiedje James M.
Published: January 2020

Microscopic methods were used to investigate the unique collar structure of the gram-negative sulfate-reducing bacterium, strain DCB-1. Polar cell growth apparently occurred from the collar. When the daughter cell was approximately equal in length to the mother cell and the collar was thus centrally located, cell division occurred within the collar region. Division was by a novel mechanism which conserved the collar of the mother cell and gave rise to a new collar of the daughter cell. Cells of DCB-1 were also found to contain stacked internal membranes and glycogen bodies.
Role of Polysulfides in Reduction of Elemental Sulfur by the Hyperthermophilic Archaebacterium
Pyrococcus furiosus
Authors: Blumentals I. I. , Itoh M. , Olson G. J. , Kelly R. M.
Published: January 2020

Polysulfides formed through the breakdown of elemental sulfur or other sulfur compounds were found to be reduced to H
2
S by the hyperthermophilic archaebacterium
Pyrococcus furiosus
during growth. Metabolism of polysulfides by the organism was dissimilatory, as no incorporation of
35
S-labeled elemental sulfur was detected. However, [
35
S]cysteine and [
35
S]methionine were incorporated into cellular protein. Contact between the organism and elemental sulfur is not necessary for metabolism. The sulfide generated from metabolic reduction of polysulfides dissociates to a strong nucleophile, HS
−
, which in turn opens up the S
8
elemental sulfur ring. In addition to H
2
S,
P. furiosus
cultures produced methyl mercaptan in a growth-associated fashion.
Production of Escherichia coli-specific hybridomas by using gnotobiotic mice
Authors: Tartera C , Davis K , Colwell R R
Published: January 2020

Monoclonal antibodies provide a rapid and specific means of direct detection of microorganisms in water and food samples. However, monoclonal antibodies specific for some bacteria are difficult to obtain; a good example of such a bacterium is Escherichia coli. Gnotobiotic BALB/c mice immunized with whole-cell preparations of heat-treated strains of E. coli and subjected to high-frequency antigen injection showed a significant increase in the number of specific hybridomas produced. Fusions obtained by using regular BALB/c mice immunized by using standard immunization protocols produced nonspecific hybridomas. Twenty-one stable hybridomas that did not cross-react with Klebsiella pneumoniae ATCC 13883 or Citrobacter freundii 1604770 were obtained from gnotobiotic mice. The bacterial strains were selected for the specificity tests because of their high cross-reactivity, which has been detected in previous fusion experiments. The method of immunization described here offers the potential of improving the production of highly specific hybridomas for bacteria which have been difficult to obtain.