bluuebunny/crossref_metadata_2025 huggingface dataset:
Destruction of the outer membrane permeability barrier of Escherichia coli by heat treatment
Authors: Tsuchido T , Katsui N , Takeuchi A , Takano M , Shibasaki I
Published: January 2020

Heat treatment of a wild-type Escherichia coli strain at 55 degrees C in 50 mM Tris-hydrochloride buffer with or without 10 mM magnesium sulfate or HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) buffer at pH 8.0 caused an increase in cell surface hydrophobicity. By determining the location of n-hexadecane droplets attached to cells by phase-contrast microscopy, the septal and polar regions of heated cells appeared to become the most frequently hydrophobic. Some of the lipopolysaccharide molecules in the outer membrane were released from heated cells, and the cells became susceptible to the hydrolytic action of added phospholipase C. Heat-treated cells also became permeable to the hydrophobic dye crystal violet, which was added externally. The release of part of the outer membrane by heat treatment appeared to bring about the disorganization of the outer membrane structure and, as a consequence, to result in the partial disruption of the permeability barrier function of the outer membrane. Tris was found to enhance damage to the outer membrane by heat.
PA-1, a Versatile Anaerobe Obtained in Pure Culture, Catabolizes Benzenoids and Other Compounds in Syntrophy with Hydrogenotrophs, and P-2 plus
Wolinella
sp. Degrades Benzenoids
Authors: Barik Sudhakar , Brulla W. J. , Bryant M. P.
Published: January 2020

Methanogenic enrichments catabolizing 13 mM phenylacetate or 4 mM phenol were established at 37�C, using a 10% inoculum from a municipal anaerobic digester. By using agar roll tubes of the basal medium plus 0.1% yeast extract-25 mM fumarate, a hydrogenotrophic lawn of
Wolinella succinogenes
and phenol or phenylacetate, strains P-2 and PA-1, respectively, were isolated in coculture with
W. succinogenes.
With the lawn deleted, PA-1 was isolated in pure culture. Strain P-2 is apparently a new species of anaerobic, motile, gram-negative, spindle-shaped, small rod that as yet has been grown only in coculture with
W. succinogenes.
It used phenol, hydrocinnamate, benzoate, and phenylacetate as energy sources. Product recovery by the coculture, per mole of phenol and 4.4 mol of fumarate used, included 2.03, 0.12, 0.08, and 3.23 mol, respectively, of acetate, propionate, butyrate, and succinate. Carbon recovery was 75% and H recovery was 80%, although CO
2
and a few other possible products were not determined. That P-2 is an obligate proton-reducing acetogen and possible pathways for its degradation of phenol are discussed. Strain PA-1 is apparently a new species of anaerobic, motile, relatively small, gram-negative rod. It utilized compounds such as phenylacetate, hydrocinnamate, benzoate, phenol, resorcinol, gallate, 4-aminophenol, 2-aminobenzoate, pyruvate, Casamino Acids, and aspartate as energy sources in coculture with
W. succinogenes.
Per mole of phenylacetate and 1.44 mol of fumarate used, 1.04, 0.53, and 0.78 mol of acetate, propionate, and succinate, respectively, were recovered from the coculture. Only about 50% of the carbon and H were recovered. In coculture with
Methanospirillum hungatei
, 0.96 mol of acetate and 0.25 mol of methane were recovered per mol of pyruvate used; 0.90 mol of acetate and 0.33 mol of methane, per mol of fumarate used; 0.93 mol of acetate and 0.54 mol of methane, per mol of aspartate used; and 1.71 mol of acetate and 0.57 mol of methane, per mol of glucose used. Carbon and H recoveries, assuming CO
2
and ammonia were produced in stoichiometric amounts, were 97 and 98% for pyruvate, 72.5 and 82% for fumarate, 96.5 and 98% for aspartate, and 61.8 and 76% for glucose. No explanation such as contamination could be found for the fact that the coculture PA-1 plus
Wolinella
sp. did not use glucose; after growth with
M. hungatei
on pyruvate, however, the latter coculture used glucose. The PA-1 pure culture produced 0.86 mol of propionate per mol of succinate used during growth. PA-1 produced a small amount of H
2
. Strain PA-1 is the most versatile anaerobic bacterium yet known that catabolizes monobenzenoids in the absence of electron acceptors such as sulfate or nitrate.
Microbial Decomposition of Cellulose in Acidifying Lakes of South-Central Ontario
Authors: Hoeniger Judith F. M.
Published: January 2020

The rate of cellulose breakdown and density of bacterial populations were measured in the epilimnetic sediments and water columns of lakes in central Ontario that differ in pH, alkalinity, and nutrient status and are particularly sensitive to acidic inputs from atmospheric decomposition. There was no significant difference in decomposition rate in either oxic or anoxic sediment when mean epilimnetic pHs were in the range 5.5 to 6.9. The importance of these findings for the breakdown of autochthonous detritus in Canadian Shield lakes is discussed. Furthermore, the results of these experiments, in which dyed strips of cellophane (regenerated cellulose) were used as substrate, were compared with results of earlier decomposition studies carried out with coarse litter (leaves, twigs). Acridine orange direct counts of bacteria in the top 1 cm of sediment ranged from 5.5 � 10
8
to 1.0 � 10
9
per g and in planktonic water samples from 1.1 � 10
6
to 1.8 � 10
6
per ml. Bacterial densities were significantly higher in both the shallow sediment (
P
< 0.01) and the water column (
P
< 0.05) of dystrophic lakes than at these sites in oligotrophic lakes.
Incidence of Vibrio cholerae and related vibrios in a coastal lagoon and seawater influenced by lake discharges along an annual cycle
Authors: Garay E , Arnau A , Amaro C
Published: January 2020

Most probable numbers of Vibrio cholerae and related vibrios were determined in Albufera Lake, Valencia, Spain, and in coastal waters under the influence of the lake discharges over the course of an annual cycle. The influence of temperature, kind of water, and characteristics of the different sampling sites on the numbers of vibrios recovered was evaluated. Maximum recovery of vibrios reached 10(3)/ml in both types of waters analyzed. V. cholerae numbers reached 10(3)/ml in the lake and 10(2) in one of the coastal sites. Frequently during the warm season, all vibrios isolated were identified as V. cholerae. Occasionally, no V. cholerae was recovered. The recovery of vibrios was significantly influenced by the temperature of the water and the type of water analyzed. Most of the V. cholerae isolates were included in Heiberg groups I and II, and nearly 50% of the strains used chitin as sole carbon source. Indole was not produced by 100% of the strains. All strains tested were non-O1 serovars.
Evidence for Separate Adhesion Mechanisms for Hydrophilic and Hydrophobic Surfaces in
Vibrio proteolytica
Authors: Paul John H. , Jeffrey Wade H.
Published: January 2020

The proteolytic enzymes pronase, trypsin, and chymotrypsin and the surfactant Triton X-100 inhibited attachment of
Vibrio proteolytica
to the hydrophobic substratum polystyrene by >97%. These treatments had no effect on attachment to hydrophilic substrata such as glass or tissue culture dishes. Both pronase and Triton X-100 effected the removal of previously attached cells from polystyrene but not from hydrophilic surfaces. Removal of cells from polystyrene by pronase left material (which we have termed footprints) that stained with the protein-specific stain Hoechst 2495 but not with the DNA-specific stain Hoechst 33342. Pronase treatment also caused a significant decrease in cell surface hydrophobicity as determined by phase partitioning in hexane or petroleum ether. Collectively, these results imply the existence of separate mechanisms for the adhesion of V.
proteolytica
to hydrophilic and hydrophobic substrata and suggest a role for protein in the latter mechanism.
Carbon Mineralization in Acidic, Xeric Forest Soils: Induction of New Activities
Authors: Tate Robert L.
Published: January 2020

Carbon mineralization was examined in Lakehurst and Atsion sands collected from the New Jersey Pinelands and in Pahokee muck from the Everglades Agricultural Area. Objectives were (i) to estimate the carbon mineralization capacities of acidic, xeric Pinelands soils in the absence of exogenously supplied carbon substrate (nonamended carbon mineralization rate) and to compare these activities with those of agriculturally developed pahokee muck, and (ii) to measure the capacity for increased carbon mineralization in the soils after carbon amendment. In most cases, nonamended carbon mineralization rates were greater in samples of the acid- and moisture-stressed Pinelands soils than in Pahokee muck collected from a fallow (bare) field. Carbon amendment resulted in augmented catabolic activity in Pahokee muck samples, suggesting that the microbial community was carbon limited in this soil. With many of the substrates, no stimulation of the catabolic rate was detected after amendment of Pinelands soils. This was documented by the observation that amendment of Pahokee muck with an amino acid mixture, glucose, or acetate resulted in a 3.0-, 3.9-, or 10.5-fold stimulation of catabolic activity, respectively, for the added substrate. In contrast, amendment of the Pinelands soils resulted in increased amino acid and acetate catabolic rates in Lakehurst sand and increased acetate metabolism only in Atsion sand. Other activities were unchanged. The increased glucose respiration rates resulted from stimulation of existing microbial activity rather than from microbial proliferation since no change in the microbial growth rate, as estimated by the rate of incorporation of
14
C-labeled acetate into cell membranes, occurred after glucose amendment of the soils. A stimulation of microbial growth rate was recorded with glucose-amended Lakehurst sand collected from the B horizon.
Radioimmunoassay of ochratoxin A in barley
Authors: Rousseau D M , Slegers G A , Van Peteghem C H
Published: January 2020

A simple and rapid radioimmunoassay was developed for the quantitative determination of ochratoxin A in barley. [14C]ochratoxin A, with a specific activity of 130 Ci/mol, was used as the tracer. Toxin levels below 100 ng/ml required a cleanup step. Three methods (the Association of Official Analytical Chemists cleanup method, the solvent partition method, and the Extrelut 3 column cleanup method) were compared.
Genetics of ergoline alkaloid formation in Penicillium roquefortii
Authors: Hong S L , Robbers J E
Published: January 2020

Auxotrophic, spore color, and alkaloid biosynthetic mutants of Penicillium roquefortii were selected after N-methyl-N'-nitro-N-nitrosoguanidine treatment. Diploids were obtained via protoplast fusion techniques, and the segregants from a diploid were genetically analyzed. The data demonstrated the potential of parasexual recombination in this organism. Evidence was obtained which suggests that the his and sts (sensitivity to Sulfatase) genes may be linked. The genetic information obtained in this study can serve as a starting point for further mapping of genes in P. roquefortii, and indications are that this organism may serve as a promising vehicle for the genetic study of the formation of ergoline alkaloids.
Glucose Catabolism in Strains of Acidophilic, Heterotrophic Bacteria
Authors: Shuttleworth Kay L. , Unz Richard F. , Wichlacz Paul L.
Published: January 2020

Pathways of glucose catabolism, potentially operational in six strains of obligately aerobic, acidophilic bacteria, including
Acidiphilium cryptum
strain Lhet2, were investigated by short-term radiorespirometry and enzyme assays. Short-term radiorespirometry was conducted at pH 3.0 with specifically labeled [
14
C]glucose. The high rate and yield of C-1 oxidized to CO
2
indicated that the Entner-Doudoroff, pentose phosphate, or both pathways were operational in all strains. Apparent nonequivalent yields of CO
2
from C-1 and estimated CO
2
from C-4 (C-1 > C-4) were suggestive of simultaneous glucose catabolism by both pathways in all strains tested. Variation in the relative contribution of the two pathways of glucose catabolism appears to account for observed strain differences. Calculation of the actual percent pathway participation was not feasible. Enzyme assays were completed with crude extracts of glucose-grown cells to substantiate the results obtained by radiorespirometry. The key enzymes of the pentose phosphate pathway (6-phosphogluconate dehydrogenase) and the Entner-Doudoroff pathway (2-keto-3-deoxy-6-phosphogluconate aldolase and 6-phosphogluconate dehydrase) were present in all strains examined (PW2, Lhet2, KLB, OP, and QBP). However, none of the strains exhibited detectable levels of the key enzyme of the Embden-Meyerhof-Parnas pathway, 6-phosphofructokinase. All strains contained glucose-6-phosphate dehydrogenase and fructose bisphosphate aldolase. The results of the enzyme study supported the contention that the pentose phosphate and Entner-Doudoroff pathways are operational for glucose catabolism in the acidophilic heterotrophs, and that the Embden-Meyerhof-Parnas pathway is apparently absent.
Characterization of Subsurface Bacteria Associated with Two Shallow Aquifers in Oklahoma
Authors: Balkwill David L. , Ghiorse William C.
Published: January 2020

The bacterial microflora of two shallow aquifers (saturated subsurface zones) in Oklahoma was characterized by direct observation with light and electron microscopy, by plating, and by examination of colony morphology and distribution. Isolated bacterial strains were also examined. Total cell counts varied only slightly (2.9 × 10
6
to 9.8 × 10
6
g [dry wt]
−1
) from sample to sample, whereas colony counts varied widely (6.3 × 10
2
to 6.5 × 10
6
CFU g [dry wt]
−1
). Colony counts on nutritionally rich media were lower than on low-nutrient media, especially in samples from the saturated zone. The variety of colony types growing on nutritionally rich media decreased with increasing depth and saturation. Colony counts of anaerobic bacteria also decreased with depth but were at least 100-fold lower than aerobic counts on most media. Cell morphologies of bacteria grown aerobically on plates included short rods, cocci, and actinomycete-like forms. Direct light microscopic observation of sediments revealed short, rod-shaped, and coccoid bacterial cells; endospores, actinomycete spores, and eucaryotic forms were not observed by light microscopy. Electron microscopic observation of bacteria released from the samples revealed that 85 to 90% of them were coccoid, gram-positive,
Arthrobacter
-like organisms, some of which were dividing or contained completed division septa; other types of gram-positive and gram-negative bacteria were present in lower numbers. Isolated bacterial strains were able to grow on both nutritionally rich and low-nutrient media. A higher proportion of gram-negative organisms was isolated than gram-positive organisms. Most of the isolates were capable of storing polyphosphate, poly-β-hydroxybutyrate, or polysaccharide. The results of this study suggest that the microbial population of these two shallow aquifers is dominated by aerobic, nutritionally versatile bacteria that can subsist on low concentrations of organic compounds without forming specialized resting cells. Other types of microorganisms, such as facultatively anaerobic bacteria and microeucaryotes, may also be present, but they represent only a small fraction of the microflora.
Gas Metabolism Evidence in Support of the Juxtaposition of Hydrogen-Producing and Methanogenic Bacteria in Sewage Sludge and Lake Sediments
Authors: Conrad R. , Phelps T. J. , Zeikus J. G.
Published: January 2020

We developed new techniques to measure dissolved H
2
and H
2
consumption kinetics in anoxic ecosystems that were not dependent on headspace measurements or gas transfer-limited experimentation. These H
2
metabolism parameters were then compared with measured methane production rates, and estimates of H
2
production and interspecies H
2
transfer were made. The H
2
pool sizes were 205 and 31 nM in sewage sludge from an anaerobic digestor and in sediments (24 m) from Lake Mendota, respectively. The H
2
turnover rate constants, as determined by using in situ pool sizes and temperatures, were 103 and 31 h
−1
for sludge and sediment, respectively. The observed H
2
turnover rate accounted for only 5 to 6% of the expected H
2
-CO
2
-dependent methanogenesis in these ecosystems. Our results are in general agreement with the results reported previously and are used to support the conclusion that most of the H
2
-dependent methanogenesis in these ecosystems occurs as a consequence of direct interspecies H
2
transfer between juxtapositioned microbial associations within flocs or consortia.
Production and Characterization of a Polymer from
Arthrobacter
sp
Authors: Bodie Elizabeth A. , Schwartz Robert D. , Catena Anthony
Published: January 2020

An
Arthrobacter
sp. isolated from a glucose-sucrose agar plate was found to produce a neutral, extremely viscous, opalescent extracellular polymer. Growth, polymer production, and rheological properties and chemical composition of the isolated polymer were examined. The polymer was found to be substantially different from other arthrobacter polymers. Some unusual properties included irreversible loss of viscosity with high temperature and degradation of the polymer during fermentation and upon storage at 4°C. Other characteristics included dependence on sucrose for polymer production, relative pH stability, increased viscosity with increased salt concentration, and pseudoplasticity. The polymer was found to be composed primarily (if not entirely) of
d
-fructose. The fructose content and other characteristics suggested that the polymer was a levan.
Characterization of
Leuconostoc oenos
Isolated from Oregon Wines
Authors: Izuagbe Y. S. , Dohman T. P. , Sandine W. E. , Heatherbell D. A.
Published: January 2020

This study was designed to characterize isolates of
Leuconostoc
species from Oregon wines. Gram-positive cocci were isolated, and their biochemical properties and abilities to decompose malic acid were determined. All of the isolates were heterofermentative, catalase negative, and facultatively anaerobic and occurred in pairs and chains. They produced acid from glucose, fructose, mannose, ribose, cellobiose, trehalose, and salicin but not from sucrose or lactose. They did not produce ammonia from arginine or dextran from sucrose. They grew at pH values of less than 4 and in 10% ethanol. Most but not all strains produced lactic acid and carbon dioxide from malic acid, as determined by paper chromatography and respirometry, respectively. These malolactic bacteria were considered to be strains of
Leuconostoc oenos
. We compared these isolates with reference strains for relative growth at pH values of 4.0, 3.5, 3.0, and 2.8 at 22°C. The isolates were similar in their growth responses at the two highest pH levels. At pH 3.0 and 2.8, however, the strains failed to grow but revealed variable abilities to dissimilate malic acid.
Anaerobic Production of a Biosurfactant by
Bacillus licheniformis
JF-2
Authors: Javaheri Mohammad , Jenneman Gary E. , McInerney Michael J. , Knapp Roy M.
Published: January 2020

Bacillus licheniformis
JF-2 anaerobically produced a biosurfactant when grown in a glucose-mineral salts medium containing yeast extract and NaNO
3
. Surface tension of the medium was reduced from 70 to 74 mN/m to as low as 28 mN/m due to the production of an anionic biosurfactant.
Measurement of Microbial Nucleic Acid Synthesis and Specific Growth Rate by
32
PO
4
and [
3
H]Adenine: Field Comparison
Authors: Karl David M. , Bossard Peter
Published: January 2020

We compared two radiotracer methods for measuring total microbial nucleic acid synthesis and specific growth rate. Using a sample from an oligotrophic environment, we found that there was excellent agreement between the two methods.
Rhizobium
sp. Degradation of Legume Root Hair Cell Wall at the Site of Infection Thread Origin
Authors: Ridge Robert W. , Rolfe Barry G.
Published: January 2020

Using a new microinoculation technique, we demonstrated that penetration of
Rhizobium
sp. into the host root hair cell occurs at 20 to 22 h after inoculation. It did this by dissolving the cell wall maxtrix, leaving a layer of depolymerized wall microfibrils. Colony growth pressure “stretched” the weakened wall, forming a bulge into an interfacial zone between the wall and plasmalemma. At the same time vesicular bodies, similar to plasmalemmasomes, accumulated at the penetration site in a manner which parallels host-pathogen systems.
Observations of Barophilic Microbial Activity in Samples of Sediment and Intercepted Particulates from the Demerara Abyssal Plain
Authors: Deming Jody W. , Colwell Rita R.
Published: January 2020

To better understand the ecological significance of pressure effects on bacteria in the abyssobenthic boundary layer, experimental suspensions of sediments and sinking particulates were prepared from samples collected in boxcore and bottom-moored sediment traps at two stations (depth, 4,470 and 4,850m) in the Demerara abyssal plain off the coast of Brazil. Replicate samples were incubated shipboard at 3�C and at both atmospheric and deep-sea pressures (440 or 480 atm [4.46 � 10
4
or 4.86 � 10
4
kPa]) following the addition of [
14
C]glutamic acid (<10 μg liter
−1
) or yeast extract (0.025%) and the antibiotic nalidixic acid (0.002%). In seven of the eight samples supplemented with isotope, a barophilic microbial response was detected, i.e., substrate incorporation and respiration were greater under in situ pressure than at 1 atm (101.3 kPa). In the remaining sample, prepared from a sediment trap warmed to 24�C before recovery, pressure was observed to inhibit substrate utilization. Total bacterial counts by epifluorescence microscopy decreased with depth in each sediment core, as did utilization of glutamic acid. Significant percentages of the total bacterial populations in cold sediment trap samples (but not the prewarmed one or any boxcore sample) were abnormally enlarged and orange fluorescing after incubation with yeast extract and nalidixic acid under deep-sea conditions. Results indicated that in the deep sea, barophilic bacteria play a predominant role in the turnover of naturally low levels of glutamic acid, and the potential for intense microbial activity upon nutrient enrichment is more likely to occur in association with recently settled particulates, especially fecal pellets, than in buried sediments.
Fermentative and oxidative transformation of ferulate by a facultatively anaerobic bacterium isolated from sewage sludge
Authors: Grbić-Galić D
Published: January 2020

A facultatively anaerobic, gram-negative, non-sporeforming, motile rod-shaped bacterium was isolated from methanogenic consortia degrading 3-methoxy-4-hydroxycinnamate (ferulate). Consortia were originally enriched from a laboratory anaerobic digester fed sewage sludge. In the absence of exogenous electron acceptors and with the addition of 0.1% yeast extract, the isolated bacterium transformed ferulate under strictly anaerobic conditions (N2-CO2 gas phase). Ferulate (1.55 mM) was demethoxylated and dehydroxylated with subsequent reduction of the side chain, resulting in production of phenylpropinate and phenylacetate. Under aerobic conditions, the substrate was completely degraded, with transient appearance of caffeate as the first aromatic intermediate and beta-ketoadipate as an aliphatic intermediate. The pure culture has been tentatively assigned to the genus Enterobacter with the type strain DG-6 (ATCC 35929). Tentative pathways for both fermentative and oxidative degradation of ferulate are now proposed.
Isolation of histamine-producing Lactobacillus buchneri from Swiss cheese implicated in a food poisoning outbreak
Authors: Sumner S S , Speckhard M W , Somers E B , Taylor S L
Published: January 2020

A histamine-producing strain of Lactobacillus buchneri was isolated from Swiss cheese that had been implicated in an outbreak of histamine poisoning. It produced up to 4,070 nmol of histamine per ml in MRS broth supplemented with 0.1% histidine. The identification of this isolate was based on its biochemical, bacteriological, and DNA characterizations.
Protoplast formation and cell wall regeneration in Clostridium perfringens
Authors: Stal M H , Blaschek H P
Published: January 2020

A protocol was developed for the efficient production and regeneration of Clostridium perfringens protoplasts. Cell wall regeneration frequencies of up to 5% were obtained.
Isolation and partial characterization of plasmid DNA from Streptococcus thermophilus
Authors: Herman R E , McKay L L
Published: January 2020

Of 23 strains of Streptococcus thermophilus examined, 5 were found to contain a single small cryptic plasmid, designated pHM1 through pHM5. Through analysis by restriction endonuclease mapping and DNA-DNA hybridization, the five plasmids were found to be closely related. They were present in 4 to 18 copies per cell and ranged in size from 1.4 to 2.2 megadaltons. Plasmids pHM1 and pHM5, as well as pHM2 and pHM4, were found to be identical. Single restriction endonuclease sites were observed on each plasmid for PvuII and MboI. Plasmids pHM2 and pHM3 each had an additional single site for HhaI, and pHM1 had an additional single site for HindIII. The characteristics of these plasmids may make them useful for the development of cloning vectors for use in S. thermophilus.
GELRITE as an Agar Substitute for the Cultivation of Mesophilic
Methanobacterium
and
Methanobrevibacter
Species
Authors: Harris Jane E.
Published: January 2020

GELRITE was evaluated as a gelling agent for the growth of mesophilic
Methanobacterium
and
Methanobrevibacter
species. GELRITE was shown to be superior to agar in its gel strength and clarity. Viable cell counts and colony sizes of
Methanobacterium
species were greater on GELRITE-based medium compared with agar-based medium.
Regulation of Nodulation by
Rhizobium meliloti
102F15 on Its Mutant Which Forms an Unusually High Number of Nodules on Alfalfa
Authors: Paau Alan S. , Leps Walter T. , Brill Winston J.
Published: January 2020

A mutant (WL3A150) of
Rhizobium meliloti
102F51 that elicits an unusually high number of nodules on its host, alfalfa (
Medicago sativa
), supports the idea that the host may rely on early bacteroid development in the nodule or on metabolites produced in the infection thread as one of the signals to control further nodulation. This mutant was initially isolated because of its Fix
−
phenotype. It consistently formed many more nodules than all the other Fix
−
mutants isolated from strain 102F51 (a total of 11 mutants). Nodules formed by this mutant were small and white and were indistinguishable in appearance from nodules formed by the other Fix
−
mutants. An ultrastructural study of the nodules, however, showed that this mutant, although forming numerous infection threads, failed to develop into bacteroids. The ability of the mutant to form an unusually high number of nodules coulde be suppressed in a time-dependent manner by the presence of the wild type.
Holding effects on coliform enumeration in drinking water samples
Authors: McDaniels A E , Bordner R H , Gartside P S , Haines J R , Brenner K P , Rankin C C
Published: January 2020

Standard procedures for analyzing drinking water stress the need to adhere to the time and temperature conditions recommended for holding samples collected for microbiological testing. The National Drinking Water Laboratory Certification Program requires compliance with these holding limits, but some investigators have reported difficulties in meeting them. Research was conducted by standard analytical methods to determine if changes occurred when samples were held at 5 and 22 degrees C and analyzed at 0, 24, 30, and 48 h. Samples were analyzed for coliforms by the membrane filter and fermentation-tube procedures and for heterotrophs by the pour plate method. A total of 17 treated water samples were collected from a large municipal distribution system from August to December 1981, and 12 samples were collected from January to May 1983. The samples were dosed with coliforms previously isolated from the water system, Enterobacter cloacae in 1981 and Citrobacter freundii in 1983. The coliform counts declined linearly over time, and the rates of decline were significant at both 5 and 22 degrees C. Within 24 h at 22 degrees C, levels of E. cloacae and C. freundii decreased by 47 and 26%, respectively, and at 5 degrees C, E. cloacae numbers declined by 23%. Results from these representative laboratory-grown coliforms reinforced those previously obtained with naturally occurring coliforms under the same experimental conditions. Significantly, some samples with initially unacceptable counts (greater than 4/100 ml) met the safe drinking water limits after storage at 24 h at 5 and 22 degrees C and would have been classified as satisfactory.(ABSTRACT TRUNCATED AT 250 WORDS)
Isolation of Yersinia enterocolitica and related species from foods in France
Authors: Delmas C L , Vidon D J
Published: January 2020

The occurrence of Yersinia enterocolitica and related species (Y. intermedia, Y. frederiksenii, Y. kristensenii) in foods from France was investigated by using different enrichment procedures. Initially, seven procedures were evaluated with pork products. These methods included a cold preenrichment in yeast extract-rose bengal broth or in phosphate-sorbitol-bile medium, followed by selective enrichment either in Pastone-sucrose-Tris-azide broth, in modified Rappaport broth, or in bile-oxalate-sorbose broth, and then isolation onto Hektoen or cefsulodin-irgasan-novobiocin agar with or without KOH pretreatment. The best enrichment procedure in terms of percentage of positive samples obtained within the shortest time was the combination of phosphate-sorbitol-bile and bile-oxalate-sorbose with alkali treatment before isolation onto cefsulodin-irgasan-novobiocin agar. This system was then used to analyze foods other than pork. An average contamination rate of 33.5% was observed for 666 samples analyzed; pork products were by far the most contaminated, especially the so-called tartinette (96.8% of positive samples) which contained up to five different strains of Yersinia spp. Environmental serogroups of Y. enterocolitica O:5, O:39,41, O:6, and O:7,8 were predominant, but no isolate of either human pathogenic type (O:3 or O:9) was obtained.
Anaerobic Cellulolytic Bacteria from Wetwood of Living Trees
Authors: Warshaw J. E. , Leschine S. B. , Canale-Parola E.
Published: January 2020

Obligately anaerobic, mesophilic, cellulolytic bacteria were isolated from the wetwood of elm and maple trees. The isolation of these bacteria involved inoculation of selective enrichment cultures with increment cores taken from trees showing evidence of wetwood. Cellulolytic bacteria were present in the cores from seven of nine trees sampled, as indicated by the disappearance of cellulose from enrichment cultures. With two exceptions, cellulolytic activity was confined to the darker, wetter, inner section of the cores. Cellulolytic bacteria were also present in the fluid from core holes. The cellulolytic isolates were motile rods that stained gram negative. Endospores were formed by some strains. The physiology of one of the cellulolytic isolates (strain JW2) was studied in detail. Strain JW2 fermented cellobiose,
d
-glucose, glycerol,
l
-arabinose,
d
-xylose, and xylan in addition to cellulose. In a defined medium,
p
-aminobenzoic acid and biotin were the only exogenous growth factors required by strain JW2 for the fermentation of cellobiose or cellulose. Acetate and ethanol were the major nongaseous end products of cellulose fermentation. The guanine-plus-cytosine content of the DNA of strain JW2 was 33.7 mol%. Cellulolytic bacteria have not previously been reported to occur in wetwood. The isolation of such bacteria indicates that cellulolytic bacteria are inhabitants of wetwood environments and suggests that they may be involved in wetwood development.
Nonlinear estimation of the parameters of Monod kinetics that best describe mineralization of several substrate concentrations by dissimilar bacterial densities
Authors: Simkins S , Alexander M
Published: January 2020

The kinetics of mineralization of a wide range of concentrations of benzoate, glucose, and benzylamine by Pseudomonas sp., Salmonella typhimurium, and microorganisms in acclimated sewage was studied. The treatment of initial substrate concentration and population density as independent variables in nonlinear regression analysis permitted the estimation of a single value for each of the parameters of Monod kinetics that best described the mineralization of substrate at each concentration by the pure cultures and the sewage microflora. One value for each of the parameters of Monod kinetics was used for each of the three compounds to produce theoretical curves which lay close to the observed data on mineralization. Statistically significant differences existed in the values of the parameters of Monod kinetics that best described mineralization in cultures differing only in initial substrate concentration and cell density. However, for the compounds tested, the variance left by analyses using one value for each parameter of Monod kinetics was less than double the unexplained variance left by individual analyses of the data from each treatment. Although significant, this increase is small compared with the amount of variance that could be explained using only one value for each parameter of Monod kinetics.
Extracellular Enzymes Produced by the Cultivated Mushroom
Lentinus edodes
during Degradation of a Lignocellulosic Medium
Authors: Leatham Gary F.
Published: January 2020

Although the commercially important mushroom
Lentinus
(=
Lentinula
)
edodes
(Berk.) Sing. can be rapidly cultivated on supplemented wood particles, fruiting is not reliable. This study addressed the problem by developing more information about growth and development on a practical oakwood-oatmeal medium. The study determined (i) the components degraded during a 150-day incubation at 22�C, (ii) the apparent vegetative growth pattern, (iii) the likely growth-limiting nutrient, and (iv) assays that can be used to study key extracellular enzymes. All major components of the medium were degraded, lignin selectively so. The vegetative growth rate was most rapid during the initial 90 days, during which weight loss correlated with glucosamine accumulation (assayed after acid hydrolysis). The rate then slowed; in apparent preparation for fruiting, the cultures rapidly accumulated glucosamine (or its oligomer or polymer). Nitrogen was growth limiting. Certain enzyme activities were associated with the pattern of medium degradation, with growth, or with development. They included cellulolytic system enzymes, hemicellulases, the ligninolytic system, (gluco-)amylase, pectinase, acid protease, cell wall lytic enzymes (laminarinase, 1,4-β-
d
-glucosidase, β-
N
-acetyl-
d
-glucosaminidase, α-
d
-galactosidase, β-
d
-mannosidase), acid phosphatase, and laccase. Enzyme activities over the 150-day incubation period with and without a fruiting stimulus are reported. These results provide a basis for future investigations into the physiology and biochemistry of growth and fruiting.
Charcoal agar, a new growth medium for the fish disease bacterium Renibacterium salmoninarum
Authors: Daly J G , Stevenson R M
Published: January 2020

Charcoal is an effective replacement for serum in media for the isolation and culture of Renibacterium salmoninarum, the causative agent of bacterial kidney disease in salmonid fish. The medium, KDM-C, contains 10 g of peptone, 0.5 g of yeast extract, 1 g of L-cysteine hydrochloride, 1 g of activated charcoal, and 15 g of agar per liter and is adjusted to pH 6.8 with NaOH before autoclaving. Eight strains of R. salmoninarum grew from dilute inocula as well on KDM-C as on a standard serum-containing medium (KDM-2). The medium was effective for both primary isolations from fish and repeated transfers and has potential value for antigen preparation and physiological studies.
Single-site chromosomal Tn5 insertions affect the export of pectolytic and cellulolytic enzymes in Erwinia chrysanthemi EC16
Authors: Thurn K K , Chatterjee A K
Published: January 2020

Exponentially growing cells of Erwinia chrysanthemi EC16 usually export about 98% of their pectate lyase (PL) and protease, about 40% of their polygalacturonase (PG), and about 60% of their cellulase (endoglucanase or carboxymethyl cellulase; CL). By using the R plasmid, pJB4JI (pPH1JI::Mu::Tn5), three independent Tn5 insertion mutants were obtained that exported normal levels of protease but 10% or less of PL, PG, and CL. Physical analysis revealed that single copies of Tn5 had inserted into the E. chrysanthemi chromosome, producing a similar export-defective (Out-) phenotype. The synthesis of PL, PG, and CL was not affected by the Tn5 insertions. These enzymes were released from the mutants on spheroplast formation, indicating that they were located in the periplasmic space. Tn5 insertions caused the loss of a 35-kilodalton periplasmic protein, but did not alter the outer membrane protein composition. The findings are discussed with respect to the current knowledge on protein export in gram-negative bacteria.
Occurrence of multiple-antibiotic-resistant enteric bacteria in domestic sewage and oxidation lagoons
Authors: Walter M V , Vennes J W
Published: January 2020

The coliform bacterial population in the Grand Forks, N.Dak. sewage system was examined for multiple-antibiotic-resistant organisms over a 1-year period. Multiple-antibiotic-resistant coliforms were found to be common in the sewage, and their numbers remained fairly constant relative to the total coliform population throughout the year. Resistance to kanamycin, tetracycline, and ampicillin was found to be transferable at variable rates. Transfer rates were found to be temperature sensitive and were optimal at 35 degrees C. Although 75% of the multiple-antibiotic-resistant coliforms were capable of transferring resistance at some level, only 25% were capable of transferring resistance at rates greater than 10(-3) transconjugants per initial donor.
Identification of Glycolytic Enzyme Polypeptides on the Two-Dimensional Protein Map of
Saccharomyces cerevisiae
and Application to the Study of Some Wine Yeasts
Authors: Brousse Michel , Bataill� Nelly , Boucherie H�lian
Published: January 2020

Using a modification of the basic two-dimensional polyacrylamide gel electrophoresis technique, the polypeptides of the protein map of
Saccharomyces cerevisiae
involved in glycolysis were investigated. This study resulted in a reassignment of two of the seven glycolytic enzyme polypeptides previously identified (Ludwig et al., Mol. Cell. Biol. 2:117-126, 1982), those corresponding to phosphoglycerate kinase and to alcohol dehydrogenase. It also resulted in the identification of two additional glycolytic polypeptides, the enolase B monomer and the glyceraldehyde phosphate dehydrogenase B monomer. The glycolytic enzymes polypeptides so identified were investigated in 5 laboratory strains (all
S. cerevisiae
) and in 11 commerical strains used for wine making (
S. cerevisiae
and
Saccharomyces bayanus
). It appeared highly significant that a particular electrophoretic variant of the glyceraldehyde phosphate dehydrogenase B monomer was found only in the wine yeasts. Furthermore, it was strongly suggested that
S. cerevisiae
and
S. bayanus
strains are distinguishible on the basis of a different electrophoretic migration of the enolase B monomer.
Microbial Degradation of Natural Rubber Vulcanizates
Authors: Tsuchii Akio , Suzuki Tomoo , Takeda Kiyoshi
Published: January 2020

An actinomycete,
Nocardia
sp. strain 835A, grows well on unvulcanized natural rubber and synthetic isoprene rubber, but not on other types of synthetic rubber. Not only unvulcanized but also various kinds of vulcanized natural rubber products were more or less utilized by the organism as the sole source of carbon and energy. The thin film from a latex glove was rapidly degraded, and the weight loss reached 75% after a 2-week cultivation period. Oligomers with molecular weights from 10
4
to 10
3
were accumulated during microbial growth on the latex glove. The partially purified oligomers were examined by infrared and
1
H nuclear magnetic resonance and
13
C nuclear magnetic resonance spectroscopy, and the spectra were those expected of
cis
-1, 4-polyisoprene with the structure, OHC—CH
2
—[—CH
2
—C(—CH
3
)=CH —CH
2
—]

n

—CH
2
—C(=O)— CH
3
, with average values of
n
of about 114 and 19 for the two oligomers.
Aerosols containing Legionella pneumophila generated by shower heads and hot-water faucets
Authors: Bollin G E , Plouffe J F , Para M F , Hackman B
Published: January 2020

Shower heads and hot-water faucets containing Legionella pneumophila were evaluated for aerosolization of the organism with a multistage cascade impaction air sampler. Air was collected above two shower doors and from the same rooms approximately 3 ft (91 cm) from the shower doors while the hot water was running. Low numbers (3 to 5 CFU/15 ft3 [0.43 m3] of air) of L. pneumophila were recovered above both shower doors, but none was recovered from the air in either room outside the shower door. Approximately 90% (7 of 8 CFU) of the L. pneumophila recovered were trapped in aerosol particles between 1 and 5 micron in diameter. Air was collected 1 to 3 ft (30 to 91 cm) from 14 sinks while the hot water was running. Low numbers (1 to 5 CFU/15 ft3 of air) were recovered from 6 of 19 air samples obtained. Approximately 50% (6 of 13 CFU) of the organisms recovered were trapped in aerosol particles between 1 and 8 microns in diameter. Shower heads and hot-water taps containing L. pneumophila can aerosolize low numbers of the organism during routine use. The aerosol particle size is small enough to penetrate to the lower human respiratory system. Thus, these sites may be implicated as a means of transmission of L. pneumophila from potable water to the patient.
Subcellular fractionation of a hypercellulolytic mutant, Trichoderma reesei Rut-C30: localization of endoglucanase in microsomal fraction
Authors: Glenn M , Ghosh A , Ghosh B K
Published: January 2020

The growing mycelia of Trichoderma reesei Rut-C30 are richly endowed with endoplasmic reticula and a variety of pleomorphic subcellular bodies. Mycelia of the culture growing in presence of avicel pH101 was fractionated in sucrose density gradients, and several morphologically and biochemically distinct fractions were isolated. Mycelia were homogenized in a Bead Beater, and the homogenate was freed of nucleus and wall fragments by low-speed centrifugation before fractionation. Organelle-free cytosol, which did not penetrate the gradient, contained (of the total) 72% of the vanadate-sensitive ATPase, 26% of carboxymethyl cellulase (CMCase), 2% of cytochrome c reductase, and 13% of the protein. Significant fractions separated on a gradient were light vesicles containing heavily stained material inside and ribosomes attached to the outside surface, intact vesicles resembling condensing vacuoles, large vesicles derived from the plasma membrane, and heavy vesicles containing crystalline material. The light-vesicle fraction contained a large portion of the cell-bound CMCase activity. The particle-bound ATPase and cytochrome c reductase activities were concentrated in heavy fractions. The fractionation in the presence of MgCl2 improved the preservation of subcellular bodies derived from the endoplasmic reticula. Although the CMCase activity of the light-vesicle fraction was 4 times higher than the activity in the heavy-vesicle fraction, the CMCase antibody-binding capacities of both fractions were about the same. This discrepancy between the catalytic activity and the antibody-binding capacity suggests that the heavy vesicles might have contained considerable amount of inactive CMCase compared with that present in the light vesicles.
Effects of butanol on Clostridium acetobutylicum
Authors: Bowles L K , Ellefson W L
Published: January 2020

The internal pH of Clostridium acetobutylicum was determined at various stages during the growth of the organism. Even in the presence of significant quantities of acetic, butyric, and lactic acids, an internal pH of 6.2 was maintained. Experiments using N,N'-dicyclohexylcarbodiimide indicated that a functioning H+-ATPase is necessary for internal pH control. Butanol, one of the end products of the fermentation, had numerous harmful effects on C. acetobutylicum. At a concentration high enough to inhibit growth, butanol destroyed the ability of the cell to maintain internal pH, lowered the intracellular level of ATP, and inhibited glucose uptake. Experiments done at two different external pH values suggested that the butanol-mediated decrease in ATP concentration was independent of the drop in internal pH. Glucose uptake was not affected by arsenate, suggesting that uptake was not ATP dependent. The effects of butanol on C. acetobutylicum are complex, inhibiting several interrelated membrane processes.
Photochemical and Microbial Degradation of 2,4,5-Trichloroaniline in a Freshwater Lake
Authors: Hwang Huey-Min , Hodson R. E. , Lee R. F.
Published: January 2020

Surface waters from a eutrophic lake in northern Georgia were incubated with
14
C-labeled 2,4,5-trichloroaniline to study the disappearance of the parent compound and production of
14
CO
2
. There was no degradation of the compound in the dark. Under 12 h of sunlight and 12 h of darkness, 28% of the trichloroaniline was degraded in both poisoned and untreated samples. Mineralization after 24 h in poisoned and untreated lake water was 5.5 and 6.8%, respectively. Thus, 81% of the mineralization was attributable to photochemical processes, and 19% was attributable to microbial processes. Most biological mineralization was due to microbes of bacterial size (<1.0 μm). Approximately 90% of the trichloroaniline bioaccumulated was associated with organisms larger than 1.0 μm, e.g., algae. When algae were removed by filtration, the amount of trichloroaniline mineralized increased to 9.4%, compared with 6.8% in the presence of algae. The excretion of organic compounds by algae may have inhibited bacterial mineralization of photoproducts.
7 alpha-hydroxytrichodermol, a new trichothecene from Myrothecium roridum
Authors: Jarvis B B , Lee Y W , Yatawara C S , Mazzocchi D B , Flippen-Anderson J L , Gilardi R , George C
Published: January 2020

Five plant-pathogenic isolates of Myrothecium roridum from Florida produced only simple trichothecenes rather than the usual macrocyclic trichothecenes. The major metabolite was 7 alpha-hydroxytrichodermol.
Aerial Dispersal of Epiphytic Bacteria over Bean Plants
Authors: Lindemann Julianne , Upper C. D.
Published: January 2020

Plant canopies are strong sources of bacterial aerosols during sunny days when the leaves are dry. Bacterial concentration, upward flux, and deposition onto exposed petri plates were measured over snap beans during three growing seasons. A net upward flux of bacteria occurred only during the warm part of sunny days, not at night when leaves were wet with dew or when a thermal inversion was present. Aerosol source strength was positively correlated with wind speed. Upward fluxes were higher on days after rain than on days when the soil was dry. Other unidentified sources of variability in source strength probably exist. Canopy-level deposition, apparently due to intermediate-scale transport of bacteria in fairly concentrated clouds, can occur in the early evening.