bluuebunny/crossref_metadata_2025 huggingface dataset:
Production of the Mycotoxin Fumonisin B
1
by
Alternaria alternata
f. sp.
lycopersici
Authors: Chen Junping , Mirocha Chester J. , Xie Weiping , Hogge Lawrence , Olson Doug
Published: January 2020

The mycotoxin fumonisin B
1
, originally described as being produced by
Fusarium moniliforme
, was detected in liquid cultures of
Alternaria alternata
f. sp.
lycopersici
, a host-specific pathogen of tomato plants. The metabolite was detected by high-pressure liquid chromatography and mass spectrometry. Its identity was confirmed by fast atom bombardment and ion spray mass spectrometry, as well as parent-daughter tandem mass spectrometry. In three separate experiments, the concentrations found ranged between 5 and 140 ppm (μg/ml).
Diversity among
Streptomyces
Strains Causing Potato Scab
Authors: Doering-Saad Christiane , Kämpfer Peter , Manulis Shulamit , Kritzman Giora , Schneider Jörg , Zakrzewska-Czerwinska Jolanta , Schrempf Hildgund , Barash Isaac
Published: January 2020

Eighty
Streptomyces
isolates, including 35 potato scab-inducing strains and 12 reference strains of
Streptomyces scabies
, were physiologically characterized by a total of 329 miniaturized tests. Overall similarities of all strains were determined by numerical taxonomy, with the unweighted average linkage (UPGMA) algorithm and simple matching (

S
sm

) and Jaccard (

S
j

) coefficients used as measures for similarity. Three cluster groups (A to C) were defined at a similarity level of 80.1% (

S
sm

); these groups contained 14 clusters and 24 unclustered strains defined at a similarity level of 86.5% (

S
sm

). Cluster group A contained strains phenotypically related to
S. griseus
or
S. exfoliatus
, whereas cluster group B contained strains which were phenotypically related to
S. violaceus
or
S. rochei
. The majority of the pathogenic isolates and reference strains were assigned to
S. violaceus
(57%) and
S. griseus
(22%). A DNA probe derived from the rRNA operon of
S. coelicolor
IMET 40271 was used to detect restriction fragment length polymorphisms (RELPs) among 40 pathogenic and nonpathogenic
Streptomyces
isolates. Southern blots revealed a high degree of diversity among the pathogenic strains tested. No significant correlation between numerical classification and RFLP grouping of
Streptomyces
strains could be revealed. The results obtained suggest that RFLP data are of minor importance in classification of
Streptomyces
species and that genes for pathogenicity determinants are spread among different
Streptomyces
species by mobilizable elements.
Improved Methods for Cultivation of the Extremely Thermophilic Bacterium
Thermotoga neapolitana
Authors: Childers Susan E. , Vargas Madeline , Noll Kenneth M.
Published: January 2020

Growth medium components and cultivation conditions for the extremely thermophilic bacterium
Thermotoga neapolitana
were optimized. A defined marine salts medium was formulated. Trace amounts of iron stimulated growth of
T. neapolitana
, while zinc inhibited growth at concentrations exceeding 11.1 μM. Other trace metals had no effect on its growth. Of the vitamins tested, only biotin was required for optimal growth. A defined mineral medium containing 5 g of carbohydrates per liter as the carbon source and 0.5 g of cysteine per liter as the sulfur source and reductant supported growth. Growth was stimulated by inclusion of vitamin-free Casamino Acids. Elemental sulfur, cystine, and dimethyl disulfide in the growth medium enhanced growth. Elemental sulfur and cystine relieved growth inhibition by hydrogen.
T. neapolitana
formed colonies in 2 days on plates of complex medium solidified with gellan gum and in 4 days on defined medium. The efficiency of plating was determined when growing cultures were sampled both aerobically and anaerobically and plated under aerobic and anaerobic conditions. Mean plating efficiencies were improved by sampling the growing cultures under strictly anaerobic conditions. Little or no improvement was obtained by inoculating plates inside an anaerobic chamber. Plating efficiencies of approximately 80% were obtained. Polycarbonate jars with aluminum lids withstood repeated incubation at 77°C without significant deterioration of the anaerobic seal and provided the most consistent results.
Uncultivated cyanobacteria, Chloroflexus-like inhabitants, and spirochete-like inhabitants of a hot spring microbial mat
Authors: Weller R , Bateson M M , Heimbuch B K , Kopczynski E D , Ward D M
Published: January 2020

Analysis of 16S rRNA sequences retrieved as cDNA (16S rcDNA) from the Octopus Spring cyanobacterial mat has permitted phylogenetic characterization of some uncultivated community members, expanding our knowledge or diversity within this microbial community. Two new cyanobacterial 16S rRNA sequences were discovered, raising to four the number of cyanobacterial sequence types known to occur in the mat. None of the sequences found is that of the cultivated thermophilic cyanobacterium Synechococcus lividus. A new 16S rRNA sequence characteristic of green nonsulfur bacteria and their relatives was discovered, raising to two the number of such sequences known to exist in the mat. Both are unique among the 16S rRNA sequences of cultivated members of this group, including an Octopus Spring isolate of Chloroflexus aurantiacus and Heliothrix oregonensis, whose sequences we report herein. Two spirochete-like 16S rRNA sequences were discovered. One can be placed in the leptospira subdivision of the spirochete group, but the other has such a loose affiliation with the spirochete group that it might actually belong to an as yet unrecognized subdivision or even to a new eubacterial line of descent.
Production of Pyrroloquinoline Quinone by Using Methanol-Utilizing Bacteria
Authors: Urakami Teizi , Yashima Kazuya , Kobayashi Hisao , Yoshida Akio , Ito-Yoshida Chieko
Published: January 2020

A large number of methanol-utilizing bacteria were screened for extracellular production of pyrroloquinoline quinone (PQQ) by using methanol as the carbon and energy sources. Of the bacteria selected,
Hyphomicrobium
sp. strain TK 0441 was examined for PQQ production by using a jar fermentor. The amount of PQQ in the broth and the level of methanol dehydrogenase activity in the cells were increased by simply decreasing the amount of Fe added to the medium. On the other hand, extracellularly produced protein which interfered with the purification of PQQ was decreased by simply increasing the amount of Mg added to the medium. A suitable medium that contained 1 μg of Fe per ml, 150 μg of Mg per ml, and trace elements was developed. In this medium, the production of PQQ reached approximately 1 mg/ml and protein formation was low.
Selection of a Pseudomonas cepacia strain constitutive for the degradation of trichloroethylene
Authors: Shields M S , Reagin M J
Published: January 2020

Tn5 insertion mutants of Pseudomonas cepacia G4 that were unable to degrade trichloroethylene (TCE), toluene, or phenol or to transform m-trifluoromethyl phenol (TFMP) to 7,7,7-trifluoro-2-hydroxy-6-oxo-2,4-heptadienoic acid (TFHA) were produced. Spontaneous reversion to growth on phenol or toluene as the sole source of carbon was observed in one mutant strain, G4 5223, at a frequency of approximately 1 x 10(-4) per generation. One such revertant, G4 5223-PR1, metabolized TFMP to TFHA and degraded TCE. Unlike wild-type G4, G4 5223-PR1 constitutively metabolized both TFMP and TCE without aromatic induction. G4 5223-PR1 also degraded cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, and 1,1-dichloroethylene and oxidized naphthalene to alpha naphthol constitutively. G4 5223-PR1 exhibited a slight retardation in growth rate at TCE concentrations of > or = 530 microM, whereas G4 (which was unable to metabolize TCE under the same noninducing growth conditions) remained unaffected. The constitutive degradative phenotype of G4 5223-PR1 was completely stable through 100 generations of nonselective growth.
Isolation, Cultural Maintenance, and Taxonomy of a Sheath-Forming Strain of
Leptothrix discophora
and Characterization of Manganese-Oxidizing Activity Associated with the Sheath
Authors: Emerson David , Ghiorse William C.
Published: January 2020

Leptothrix discophora
SP-6 was isolated from the outflow reservoir of an artificial iron seep. Its sheathforming phenotype was maintained by slow growth in a mineral salts-vitamin-pyruvate medium under minimal aeration at 20 to 25°C. A sheathless variant, SP-6(sl), was isolated from smooth colonies that appeared on spread plates after rapid growth of SP-6 in well-aerated cultures. SP-6 and SP-6(sl) are closely related but not identical to the previously studied sheathless strain SS-1 (ATCC 43182). Increasing Mn
2+
concentrations in the growth medium of SP-6 increased the phase density of the sheath, indicating increased Mn oxide deposition in the sheath. Electron microscopy of cultures grown without added Mn
2+
revealed that the sheath consisted of a well-defined inner layer, 30 to 100 nm thick, and a diffuse outer capsular layer of variable thickness. Mn oxides were identified in the sheath by their characteristic ultrastructure, electron density, and X-ray-dispersive energy spectra. In heavily encrusted sheaths, the Mn oxides were evenly distributed in both layers of the sheath. Sheathed cells retained more Mn-oxidizing activity than did sheathless cells after washing with distilled, deionized water; the sheath retained some of its activity after an EDTA-lysozyme-detergent treatment which removed the cells. An ultrafiltration-dialysis procedure significantly increased the recovery of activity from spent media of SP-6 over that reported previously for SS-1 (L.F. Adams and W.C. Ghiorse, J. Bacteriol. 169:1279-1285, 1987). A 108-kDa Mn-oxidizing protein was identified in concentrated spent media of SP-6 and SP-6(sl), and the activity of the concentrates showed stability in detergents comparable to that of SS-1 and patterns of heat inactivation and chemical inhibition similar to those of SS-1.
Evaluation of Culture Techniques for Isolation of
Pseudomonas pseudomallei
from Soil
Authors: Ashdown Leslie R. , Clarke Sue G.
Published: January 2020

Three selective enrichment broths and four selective agar media were evaluated for their ability to support the growth of
Pseudomonas pseudomallei
both at 35°C and at ambient temperature (range, 20 to 32°C; mean, 25°C). Colony counts of 50 strains of
P. pseudomallei
and recovery studies with 1 soil strain in 60 simulated soil samples demonstrated that enrichment with Trypticase soy broth incorporating 5 mg of crystal violet per liter and 20 mg of colistin per liter (CVCB) and subculture to Ashdown medium supported the growth of all 50 strains and produced the highest recovery rates with the greatest suppression of other soil flora. An enrichment broth of MacConkey broth (purple) incorporating 10 mg of crystal violet per liter, 5 mg of bromcresol purple per liter, 25 mg of gentamicin per liter, and 650 mg of streptomycin per liter showed greater suppression of soil bacteria than CVCB, but it failed to support the growth of three strains of
P. pseudomallei.
Recovery rates were essentially the same irrespective of whether the soil samples were incubated at 35°C or at ambient temperature, provided cultures were incubated in protected shade for an extended period. This is an important feature for field work in large-scale epidemiological surveys in which resources are limited.
Soil Bacterial Biomass, Activity, Phospholipid Fatty Acid Pattern, and pH Tolerance in an Area Polluted with Alkaline Dust Deposition
Authors: Bååth E. , Frostegård Å. , Fritze H.
Published: January 2020

Soil bacterial biomass, phospholipid fatty acid pattern, pH tolerance, and growth rate were studied in a forest area in Finland that is polluted with alkaline dust from an iron and steel works. The pollution raised the pH of the humus layer from 4.1 to 6.6. Total bacterial numbers and the total amounts of bacterial phospholipid fatty acids in the humus layer did not differ between the unpolluted control sites and the polluted ones. The number of CFU increased by a factor of 6.4 in the polluted sites compared with the controls, while the bacterial growth rate, measured by the thymidine incorporation technique, increased about 1.8-fold in the polluted sites. A shift in the pattern of phospholipid fatty acids indicated a shift in the bacterial species composition. The largest proportional increase was found for the fatty acid 10Me18:0, which indicated an increase in the number of actinomycetes in the polluted sites. The levels of the fatty acids
i
14:0, 16:1ω5,
cy
17:0, 18:1ω7, and 19:1 also increased in the polluted sites while those of fatty acids 15:0,
i
15:0, 10Me16:0, 16:1ω7t, 18:1ω9, and
cy
19:0 decreased compared with the unpolluted sites. An altered pH tolerance of the bacterial assemblage was detected either as a decrease in acid-tolerant CFU in the polluted sites or as altered bacterial growth rates at different pHs. The latter was estimated by measuring the thymidine incorporation rate of bacteria extracted from soil by homogenization-centrifugation at different pHs.
Reduction of Selenate and Selenite to Elemental Selenium by a
Pseudomonas stutzeri
Isolate
Authors: Lortie L. , Gould W. D. , Rajan S. , McCready R. G. L. , Cheng K.-J.
Published: January 2020

A
Pseudomonas stutzeri
isolate rapidly reduced both selenite and selenate ions to elemental selenium at initial concentrations of both anions of up to 48.1 mM. Optimal selenium reduction occurred under aerobic conditions between pH 7.0 and 9.0 and at temperatures of 25 to 35°C. Reduction of both selenite and selenate was unaffected by a number of anions except for sulfite, chromate, and tungstate ions, which inhibited both growth and reduction.
Divergence of Genomic Sequences between
Lactococcus lactis
subsp.
lactis
and
Lactococcus lactis
subsp.
cremoris
Authors: Godon Jean-Jacques , Delorme Christine , Ehrlich S. Dusko , Renault Pierre
Published: January 2020

Relatedness between
Lactococcus lactis
subsp.
cremoris
and
L. lactis
subsp.
lactis
was assessed by Southern hybridization analysis, with cloned chromosomal genes as probes. The results indicate that strains of the two subspecies form two distinct groups and that the DNA sequence divergence between
L. lactis
subsp.
lactis
and
L. lactis
subsp.
cremoris
is estimated to be between 20 and 30%. The previously used phenotypic criteria do not fully discriminate between the groups; therefore, we propose a new classification which is based on DNA homology. In agreement with this revised classification, the
L. lactis
subsp.
lactis
and
L. lactis
subsp.
cremoris
strains from our collection have distinct phage sensitivities.
Purification and Properties of an Extracellular Agarase from
Alteromonas
sp. Strain C-1
Authors: Leon Oscar , Quintana Luis , Peruzzo Gina , Slebe Juan Carlos
Published: January 2020

A marine bacterial strain isolated from the Bay of San Vicente, Chile, was identified as
Alteromonas
sp. strain C-1. In the presence of agar, this strain produced high levels of an extracellular agarase. The production of agarase was repressed by glucose, with a parallel decrease in bacterial growth. The enzyme was purified to homogeneity by anion-exchange chromatography and gel filtration, with an overall yield of 45%. The enzyme has a molecular weight of 52,000, is salt sensitive, and hydrolyzes agar, yielding neoagarotetraose as the main product, with an optimum pH of about 6.5.
Application of ozone disinfection to remove Enterococcus seriolicida, Pasteurella piscicida, and Vibrio anguillarum from seawater
Authors: Sugita H , Asai T , Hayashi K , Mitsuya T , Amanuma K , Maruyama C , Deguchi Y
Published: January 2020

Survival of bacterial fish pathogens, including Enterococcus seriolicida, Vibrio anguillarum, and Pasteurella piscicida, in ozonated seawater was determined in a batch system. Bacterial counts of all fish pathogens decreased at more than 0.040 to 0.060 mg of total residual oxidants (TROs) per liter, whereas no decrease in viable counts was observed at less than 0.018 to 0.028 mg of TROs per liter. The 99% inactivation point was achieved at concentrations of 0.111 mg/liter for E. seriolicida, 0.063 mg/liter for P. piscicida, and 0.064 mg/liter for V. anguillarum within 1 min. Moreover, the mean 99 and 99.9% killing concentration-contact time (C.t) products were 0.123 and 0.186 mg.min/liter for E. seriolicida, 0.056 and 0.084 mg.min/liter for P. piscicida, and 0.081 and 0.123 mg.min/liter for V. anguillarum, respectively. However, the mean 99 and 99.9% C.t products for the mixed population in coastal seawater were 0.200 and 0.621 mg.min/liter. These results strongly suggest that ozone treatment at more than 1.0 mg of TROs per liter for several minutes is able to disinfect seawater for mariculture efficiently.
Analysis of exopolysaccharide production by Lactobacillus casei CG11, isolated from cheese
Authors: Kojic M , Vujcic M , Banina A , Cocconcelli P , Cerning J , Topisirovic L
Published: January 2020

Exopolysaccharide-producing Lactobacillus casei CG11 was isolated from soft, white, homemade cheese. In basal minimal medium, it produces a neutral heteropolysaccharide consisting predominantly of glucose (about 75%) and rhamnose (about 15%). Plasmid curing experiments revealed that exopolysaccharide production by strain CG11 is linked to a plasmid approximately 30 kb in size.
Effect of different holding regimens on the intestinal microflora of herring (Clupea harengus) larvae
Authors: Hansen G H , Strøm E , Olafsen J A
Published: January 2020

The aerobic intestinal microflora of 2-week-old herring (Clupea harengus) larvae was characterized by using conventional microbiological methods and electron microscopy. Larvae were hatched and kept in filtered seawater or in seawater with penicillin and streptomycin. The gastrointestinal tract of herring larvae is essentially a straight tube divided into two compartments. Light microscopy revealed bacteria present in a progressively increasing amount throughout the length of the gastrointestinal tract from esophagus to anus. The posterior region of the intestinal lumen appeared completely occluded with bacteria. The intestinal microflora consisted mainly of members of the genera Pseudomonas and Alteromonas in the larvae incubated in filtered seawater, whereas Flavobacterium spp. dominated in larvae exposed to antibiotics. The intestinal microflora of untreated fish larvae was sensitive to all tested antibiotics, whereas multiple resistance was found in the intestinal microflora of the group given antibiotics. Thus, a dramatic change in the microflora resulted from incubation with antibiotics. Nonpigmented yeasts were detected in both larval groups. Ciliated epithelial cells were observed in the midgut, probably propeling bacteria towards the hindgut, where endocytosis of bacteria has been demonstrated. These findings suggest that transport and sequestering mechanisms resembling those of invertebrates may be found in the gut of fish larvae. The possible significance for larval health and nutrition is discussed.
Biodegradation of the herbicide bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) by purified pentachlorophenol hydroxylase and whole cells of Flavobacterium sp. strain ATCC 39723 is accompanied by cyanogenesis
Authors: Topp E , Xun L Y , Orser C S
Published: January 2020

A pentachlorophenol (PCP)-degrading Flavobacterium sp. (strain ATCC 39723) degraded bromoxynil with the production of bromide and cyanide. No aromatic intermediates were detected in the spent culture fluid. The cyanide produced upon bromoxynil metabolism was inhibitory to the Flavobacterium sp. Whole cells degraded PCP more rapidly than they did bromoxynil. Bromoxynil metabolism and PCP metabolism were coinduced, either substrate serving as the inducer. Purified PCP hydroxylase degraded bromoxynil with stoichiometric accumulation of cyanide and without bromide production. A product accumulated which was more hydrophilic than bromoxynil upon high-pressure liquid chromatographic analysis and which, when analyzed by gas chromatography-mass spectrometry, had a mass spectrum consistent with that expected for dibromohydroquinone. PCP hydroxylase consumed NADPH, oxygen, and bromoxynil in a 2:1:1 molar ratio, producing 1 mol of cyanide per mol of bromoxynil degraded. We propose a pathway by which bromoxynil is metabolized by the same enzymes which degrade PCP. The initial step in the pathway is the conversion of bromoxynil to 2,6-dibromohydroquinone by PCP hydroxylase. In addition to its utility for decontaminating PCP-polluted sites, the Flavobacterium sp. may be useful for decontaminating bromoxynil spills. This is the first report of cyanide production accompanying the metabolism of a benzonitrile derivative.
Properties of a 72-kilodalton mosquitocidal protein from Bacillus thuringiensis subsp. morrisoni PG-14 expressed in B. thuringiensis subsp. kurstaki by using the shuttle vector pHT3101
Authors: Chang C , Dai S M , Frutos R , Federici B A , Gill S S
Published: January 2020

The mosquitocidal properties of Bacillus thuringiensis subsp. israelensis and B. thuringiensis subsp. morrisoni PG-14 are attributable to protein inclusions grouped together within a parasporal body. In both of these strains, the mosquitocidal activity resides in proteins with molecular masses of 27, 72, 128, and 135 kDa. In an attempt to determine the toxicity of each protein, the shuttle vector pHT3101 was used to express the cryIVD gene (encoding the 72-kDa CryIVD protein) from B. thuringiensis subsp. morrisoni in an acrystalliferous mutant of B. thuringiensis subsp. kurstaki. With this system, parasporal inclusions of the 72-kDa protein were obtained that were comparable in size, shape, and toxicity to those produced by parental B. thuringiensis subsp. morrisoni. The inclusions were bar shaped, measured 500 by 300 by 150 nm, and were easily visible with phase-contrast microscopy by 16 h of cell growth. A 50% lethal concentration of 64 ng/ml for these inclusions was determined in bioassays against fourth instars of Culex quinquefasciatus, which was similar to the 50% lethal concentration of 55 ng/ml obtained for the 72-kDa inclusion from B. thuringiensis subsp. israelensis. In contrast, expression of the cryIVD gene in Escherichia coli was very low and only detectable by immunoblot analysis. These results demonstrate that the pHT3101-B. thuringiensis expression system can be used to express the CryIVD protein in quantities and with properties comparable to that obtained with the natural host. This system may prove useful for the expression of other B. thuringiensis proteins and, in particular, for reconstitution experiments with inclusions produced by the mosquitocidal subspecies of B. thuringiensis.
Pseudomonas putida KT2442 cultivated on glucose accumulates poly(3-hydroxyalkanoates) consisting of saturated and unsaturated monomers
Authors: Huijberts G N , Eggink G , de Waard P , Huisman G W , Witholt B
Published: January 2020

The biosynthesis of poly(3-hydroxyalkanoates) (PHAs) by Pseudomonas putida KT2442 during growth on carbohydrates was studied. PHAs isolated from P. putida cultivated on glucose, fructose, and glycerol were found to have a very similar monomer composition. In addition to the major constituent 3-hydroxydecanoate, six other monomers were found to be present: 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydodecanoate, 3-hydroxydodecenoate, 3-hydroxytetradecanoate, and 3-hydroxytetradecenoate. The identity of all seven 3-hydroxy fatty acids was established by gas chromatography-mass spectrometry, one-dimensional 1H-nuclear magnetic resonance, and two-dimensional double-quantum filtered correlation spectroscopy 1H-nuclear magnetic resonance. The chemical structures of the monomer units are identical to the structure of the acyl moiety of the 3-hydroxyacyl-acyl carrier protein intermediates of de novo fatty acid biosynthesis. Furthermore, the degree of unsaturation of PHA and membrane lipids is similarly influenced by shifts in the cultivation temperature. These results strongly indicate that, during growth on nonrelated substrates, PHA monomers are derived from intermediates of de novo fatty acid biosynthesis. Analysis of a P. putida pha mutant and complementation of this mutant with the cloned pha locus revealed that the PHA polymerase genes necessary for PHA synthesis from octanoate are also responsible for PHA formation from glucose.
Measurement of marine picoplankton cell size by using a cooled, charge-coupled device camera with image-analyzed fluorescence microscopy
Authors: Viles C L , Sieracki M E
Published: January 2020

Accurate measurement of the biomass and size distribution of picoplankton cells (0.2 to 2.0 microns) is paramount in characterizing their contribution to the oceanic food web and global biogeochemical cycling. Image-analyzed fluorescence microscopy, usually based on video camera technology, allows detailed measurements of individual cells to be taken. The application of an imaging system employing a cooled, slow-scan charge-coupled device (CCD) camera to automated counting and sizing of individual picoplankton cells from natural marine samples is described. A slow-scan CCD-based camera was compared to a video camera and was superior for detecting and sizing very small, dim particles such as fluorochrome-stained bacteria. Several edge detection methods for accurately measuring picoplankton cells were evaluated. Standard fluorescent microspheres and a Sargasso Sea surface water picoplankton population were used in the evaluation. Global thresholding was inappropriate for these samples. Methods used previously in image analysis of nanoplankton cells (2 to 20 microns) also did not work well with the smaller picoplankton cells. A method combining an edge detector and an adaptive edge strength operator worked best for rapidly generating accurate cell sizes. A complete sample analysis of more than 1,000 cells averages about 50 min and yields size, shape, and fluorescence data for each cell. With this system, the entire size range of picoplankton can be counted and measured.
Persistence of Viruses in Desert Soils Amended with Anaerobically Digested Sewage Sludge
Authors: Straub Timothy M. , Pepper Ian L. , Gerba Charles P.
Published: January 2020

Pima County, Ariz., is currently investigating the potential benefits of land application of sewage sludge. To assess risks associated with the presence of pathogenic enteric viruses present in the sludge, laboratory studies were conducted to measure the inactivation rate (
k
= log
10
reduction per day) of poliovirus type 1 and bacteriophages MS2 and PRD-1 in two sludge-amended desert agricultural soils (Brazito Sandy Loam and Pima Clay Loam). Under constant moisture (approximately -0.05 × 10
5
Pa for both soils) and temperatures of 15, 27, and 40°C, the main factors controlling the inactivation of these viruses were soil temperature and texture. As the temperature increased from 15 to 40°C, the inactivation rate increased significantly for poliovirus and MS2, whereas, for PRD-1, a significant increase in the inactivation rate was observed only at 40°C. Clay loam soils afforded more protection to all three viruses than sandy soils. At 15°C, the inactivation rate for MS2 ranged from 0.366 to 0.394 log
10
reduction per day in clay loam and sandy loam soils, respectively. At 27°C, this rate increased to 0.629 log
10
reduction per day in clay loam soil and to 0.652 in sandy loam soil. A similar trend was observed for poliovirus at 15°C (
k
= 0.064 log
10
reduction per day, clay loam;
k
= 0.095 log
10
reduction per day, sandy loam) and 27°C (
k
= 0.133 log
10
reduction per day, clay loam;
k
= 0.154 log
10
reduction per day, sandy loam). Neither MS2 nor poliovirus was recovered after 24 h at 40°C. No reduction of PRD-1 was observed after 28 days at 15°C and after 16 days at 27°C. At 40°C, the inactivation rates were 0.208 log
10
reduction per day in amended clay loam soil and 0.282 log
10
reduction per day in sandy loam soil. Evaporation to less than 5% soil moisture completely inactivated all three viruses within 7 days at 15°C, within 3 days at 27°C, and within 2 days at 40°C regardless of soil type. This suggests that a combination of high soil temperature and rapid loss of soil moisture will significantly reduce risks caused by viruses in sludge.
Reduction of Campylobacter jejuni colonization of chicks by cecum-colonizing bacteria producing anti-C. jejuni metabolites
Authors: Schoeni J L , Doyle M P
Published: January 2020

Cecum-colonizing bacteria were isolated from Campylobacter jejuni-free White Leghorn (Gallus domesticus) laying hens and screened for the ability to produce anti-C. jejuni metabolites. Nine isolates were obtained that possessed this characteristic. The peroral administration of the nine isolates as a mixture (ca. 10(9) per chick) to 1-day-old chicks was followed 1 week later by peroral inoculation of Campylobacter jejuni (ca. 10(9) per chick) to determine if the cecal isolates could protect chicks from colonization by campylobacters. The nine-strain mixture of cecal bacteria provided from 41 to 85% protection from C. jejuni colonization. The protective bacteria were reduced to a mixture of three strains on the basis of their ability to utilize mucin as a sole substrate for growth. These strains included Klebsiella pneumoniae 23, Citrobacter diversus 22, and Escherichia coli (O13:H-) 25. Four feeding trials with this three-strain mixture provided from 43 to 100% (average, 78%) protection from C. jejuni colonization. The dominant cecal bacterium of chicks treated with the three-strain mixture was consistently E. coli O13:H-. Similarly, three trials with only E. coli 25 used as the protective bacterium resulted in 49 to 72% (average, 59%) protection from C. jejuni colonization, with E. coli O13:H- being the dominant cecal bacterium in all cases. Although not completely effective, E. coli 25 substantially reduced the incidence of C. jejuni colonization of chicks. For all trials, fewer C. jejuni were present in the ceca of colonized chicks receiving the protective bacteria before exposure to C. jejuni than in chicks receiving only C. jejuni.(ABSTRACT TRUNCATED AT 250 WORDS)
Disinfection of drinking water by using a novel electrochemical reactor employing carbon-cloth electrodes
Authors: Matsunaga T , Nakasono S , Takamuku T , Burgess J G , Nakamura N , Sode K
Published: January 2020

A novel electrochemical reactor employing carbon-cloth electrodes was constructed for disinfection of drinking water. Escherichia coli K-12 (10(2) cells per cm3) was sterilized when a cell suspension was passed through the reactor at a dilution rate of 6.0 h-1, and a potential of 0.7 V versus a saturated calomel electrode was applied to an electrode. The survival ratio increased with increasing dilution rate but was less than 0.1% at dilution rates of less than 6.0 h-1. Although the survival ratio increased with increasing cell concentration above 10(3) cells per cm3, the disinfection rate also increased. The disinfection rate was 6.0 x 10(2) cells per cm3 per h at a cell concentration of 10(2) cells per cm3. Continuous sterilization of E. coli cells was carried out for 24 h. Sterilization is based on an electrochemical reaction between the electrode and the cell which is mediated by intracellular coenzyme A. Sterilization of drinking water by using this reactor was successfully performed, demonstrating the potential of such a reactor for clean and efficient water purification.
Potential early intermediates in anaerobic benzoate degradation by Rhodopseudomonas palustris
Authors: Gibson K J , Gibson J
Published: January 2020

Alkali-treated extracts of Rhodopseudomonas palustris growing photosynthetically on benzoate were examined by gas chromatography/mass spectrometry for partially reduced benzoate derivatives. Two cyclic dienes, cyclohexa-2,5-diene-1-carboxylate and cyclohexa-1,4-diene-1-carboxylate, were detected. Either compound supported cell growth as effectively as benzoate. These results suggest that these cyclohexadienecarboxylates, probably as their coenzyme A esters, are the initial reduction products formed during anaerobic benzoate metabolism by R. palustris.
Comparison of acetate utilization among strains of an aceticlastic methanogen, Methanothrix soehngenii
Authors: Ohtsubo S , Demizu K , Kohno S , Miura I , Ogawa T , Fukuda H
Published: January 2020

The kinetics of acetate utilization by concentrated suspensions of cells was examined in five strains of Methanothrix soehngenii. The rate of acetate utilization by all strains was dependent on the initial acetate concentration and followed simple Michaelis-Menten kinetics. The ability to utilize acetate differed among the various strains of M. soehngenii and was highest in the strain designated MTAS.
Differentiation of Listeria monocytogenes, Listeria innocua, Listeria ivanovii, and Listeria seeligeri by pulsed-field gel electrophoresis
Authors: Howard P J , Harsono K D , Luchansky J B
Published: January 2020

Clamped homogeneous electric field analysis of Listeria DNA with ApaI, AscI, SmaI, or NotI revealed species- and serotype-specific differences in genomic fingerprints. Clamped homogeneous electric field analysis may prove useful, therefore, in epidemiologic studies. Also, the summation of individually sized AscI fragments of genomic DNA from L. monocytogenes serotype 4b 101M and Scott A indicated genome lengths of 2,925 and 3,046 kb, respectively.
The Soybean
Rj4
Allele Restricts Nodulation by
Bradyrhizobium japonicum
Serogroup 123 Strains
Authors: Sadowsky Michael J. , Cregan Perry B.
Published: January 2020

Of nine
Bradyrhizobium japonicum
serogroup 123 strains examined, 44% were found to be restricted for nodulation by cultivar Hill. Nodulation studies with soybean isoline BARC-2 confirmed that the soybean
Rj4
allele restricts nodulation by the same serogroup 123 isolates. Immunological analyses indicated that
B. japonicum
strains in serogroups 123 and 31 share at least one surface somatic antigen.
Production of an extracellular polyethylene-degrading enzyme(s) by Streptomyces species
Authors: Pometto A L , Lee B T , Johnson K E
Published: January 2020

Extracellular culture concentrates were prepared from Streptomyces viridosporus T7A, Streptomyces badius 252, and Streptomyces setonii 75Vi2 shake flask cultures. Ten-day-heat-treated (70 degrees C) starch-polyethylene degradable plastic films were incubated with shaking with active or inactive enzyme for 3 weeks (37 degrees C). Active enzyme illustrated changes in the films' Fourier transform infrared spectra, mechanical properties, and polyethylene molecular weight distributions.
Effect of nitrogen limitation on long-side-chain poly-beta-hydroxyalkanoate synthesis by Pseudomonas resinovorans
Authors: Ramsay B A , Saracovan I , Ramsay J A , Marchessault R H
Published: January 2020

Pseudomonas resinovorans produced poly-beta-hydroxyalkanoates (PHAs) when grown on hydrocarbons but not on glucose. In a chemostat culture, the PHA composition was beta-hydroxybutyrate (C4)-beta-hydroxyhexanoate (C6)-beta-hydroxyoctanoate (C8)-beta-hydroxydecanoate (C10) (1:15:75:9) on octanoate and C4-C6-C8-C10 (8:62:23:7) on hexanoic acid. Contrary to the reported behavior of Pseudomonas oleovorans, the PHA accumulation rate increased under ammonium limitation on octanoate.
Metabolism of dibenzo-p-dioxin by Sphingomonas sp. strain RW1
Authors: Wittich R M , Wilkes H , Sinnwell V , Francke W , Fortnagel P
Published: January 2020

In the course of our screening for dibenzo-p-dioxin-utilizing bacteria, a Sphingomonas sp. strain was isolated from enrichment cultures inoculated with water samples from the river Elbe. The isolate grew with both the biaryl ethers dibenzo-p-dioxin and dibenzofuran (DF) as the sole sources of carbon and energy, showing doubling times of about 8 and 5 h, respectively. Biodegradation of the two aromatic compounds initially proceeded after an oxygenolytic attack at the angular position adjacent to the ether bridge, producing 2,2',3-trihydroxydiphenyl ether or 2,2',3-trihydroxybiphenyl from the initially formed dihydrodiols, which represent extremely unstable hemiacetals. Results obtained from determinations of enzyme activities and oxygen consumption suggest meta cleavage of the trihydroxy compounds. During dibenzofuran degradation, hydrolysis of 2-hydroxy-6-oxo-6-(2-hydroxyphenyl)-hexa-2,4-dienoate yielded salicylate, which was branched into the catechol meta cleavage pathway and the gentisate pathway. Catechol obtained from the product of meta ring fission of 2,2',3-trihydroxydiphenyl ether was both ortho and meta cleaved by Sphingomonas sp. strain RW1 when this organism was grown with dibenzo-p-dioxin.
Development of a universal diluting fluid for membrane filtration sterility testing
Authors: Proud D W , Sutton S V
Published: January 2020

A universal diluting fluid (UDF) was developed for use in membrane filtration sterility testing. Diuting fluid is used to free the filter membrane of preservative residues which could inhibit microbial recovery. Current procedures employ one of several fluids described by the United States Pharmacopeia. UF was designed to utilize the neutralizing capabilities of a combination of inactivating agents while minimizing any inherent microbial toxicity. This formulation eliminates the need for multiple types of preservative-specific diluting fluids. Its neutralizing effectiveness was examined against several common preservative agents used in health care products. UDF provides significantly better microorganism recovery than dilution alone among a wide range of preservative classes.
Inhibition of polyketide synthesis in Alternaria alternata by the fatty acid synthesis inhibitor cerulenin
Authors: Hiltunen M , Söderhäll K
Published: January 2020

The fatty acid synthase inhibitor cerulenin (50 to 100 micrograms/ml) inhibited production of the polyketide mycotoxins alternariol (AOH) and alternariol monomethyl ether (AME) by the mold Alternaria alternata. The results suggested that AOH synthesis was inhibited by a direct mechanism by cerulenin, whereas production of AME was probably limited by a shortage of the precursor AOH.
Reductive dechlorination of a polychlorinated biphenyl congener and hexachlorobenzene by vitamin B12
Authors: Assaf-Anid N , Nies L , Vogel T M
Published: January 2020

The polychlorinated biphenyl congener 2,3,4,5,6-pentachlorobiphenyl and hexachlorobenzene were reductively dechlorinated in an aqueous biomimetic model system containing vitamin B12. The products of 2,3,4,5,6-pentachlorobiphenyl dechlorination were 2,3,5,6- and 2,3,4,6-tetrachlorobiphenyl. Hexachlorobenzene dechlorinated to pentachlorobenzene and a mixture of 1,2,4,5- and 1,2,3,5-tetrachlorobenzene. The proton from water was shown to be the source of the hydrogen atom used for the replacement of chlorine on the biphenyl ring.
Detection of
Renibacterium salmoninarum
, the Causative Agent of Bacterial Kidney Disease in Salmonid Fish, from Pen-Cultured Coho Salmon
Authors: Sakai Masahiro , Kobayashi Masanori
Published: January 2020

The detection of
Renibacterium salmoninarum
antigen from pen-cultured coho salmon was attempted. Flounder (
Limanda herzensteini
) (
n
= 24), greenling (
Hexagrammos otakii
) (
n
= 5), Japanese sculpin (
Cottus japonicus
) (
n
= 1), and flathead (
Platycephalus indicus
) (
n
= 22) captured by fishing around coho salmon net pens were examined for the presence of
R. salmoninarum
antigen by an indirect dot blot assay and by an indirect fluorescent-antibody technique using polyclonal and monoclonal antibodies.
R. salmoninarum
antigen was detected from kidney samples of one greenling and six flathead. Moreover, 86 scallops (
Patinopecten yessoensis
) were hung from the edge of the net pen for 50 days, and
R. salmoninarum
antigen was demonstrated in 31 samples by the indirect dot blot assay and the indirect fluorescent-antibody technique.
Microbial degradation of toluene under sulfate-reducing conditions and the influence of iron on the process
Authors: Beller H R , Grbić-Galić D , Reinhard M
Published: January 2020

Toluene degradation occurred concomitantly with sulfate reduction in anaerobic microcosms inoculated with contaminated subsurface soil from an aviation fuel storage facility near the Patuxent River (Md.). Similar results were obtained for enrichment cultures in which toluene was the sole carbon source. Several lines of evidence suggest that toluene degradation was directly coupled to sulfate reduction in Patuxent River microcosms and enrichment cultures: (i) the two processes were synchronous and highly correlated, (ii) the observed stoichiometric ratios of moles of sulfate consumed per mole of toluene consumed were consistent with the theoretical ratio for the oxidation of toluene to CO2 coupled with the reduction of sulfate to hydrogen sulfide, and (iii) toluene degradation ceased when sulfate was depleted, and conversely, sulfate reduction ceased when toluene was depleted. Mineralization of toluene was confirmed in experiments with [ring-U-14C]toluene. The addition of millimolar concentrations of amorphous Fe(OH)3 to Patuxent River microcosms and enrichment cultures either greatly facilitated the onset of toluene degradation or accelerated the rate once degradation had begun. In iron-amended microcosms and enrichment cultures, ferric iron reduction proceeded concurrently with toluene degradation and sulfate reduction. Stoichiometric data and other observations indicate that ferric iron reduction was not directly coupled to toluene oxidation but was a secondary, presumably abiotic, reaction between ferric iron and biogenic hydrogen sulfide.
Anaerobic degradation of toluene and xylene by aquifer microorganisms under sulfate-reducing conditions
Authors: Edwards E A , Wills L E , Reinhard M , Grbić-Galić D
Published: January 2020

Toluene and the three isomers of xylene were completely mineralized to CO2 and biomass by aquifer-derived microorganisms under strictly anaerobic conditions. The source of the inoculum was gasoline-contaminated sediment from Seal Beach, Calif. Evidence confirming that sulfate was the terminal electron acceptor is presented. Benzene and ethylbenzene were not degraded under the experimental conditions used. Successive transfers of the mixed cultures that were enriched from aquifer sediments retained the ability to degrade toluene and xylenes. Greater than 90% of 14C-labeled toluene or 14C-labeled o-xylene was mineralized to 14CO2. The doubling time for the culture grown on toluene or m-xylene was about 20 days, and the cell yield was about 0.1 to 0.14 g of cells (dry weight) per g of substrate. The accumulation of sulfide in the cultures as a result of sulfate reduction appeared to inhibit degradation of aromatic hydrocarbons.
Extensive In Vitro Hyphal Growth of Vesicular-Arbuscular Mycorrhizal Fungi in the Presence of CO
2
and Flavonols
Authors: Bécard G. , Douds D. D. , Pfeffer P. E.
Published: January 2020

Various flavonoids were tested for their ability to stimulate in vitro growth of germinated spores of vesicular-arbuscular mycorrhizal fungi. Experiments were performed in the presence of 2% CO
2
, previously demonstrated to be required for growth of
Gigaspora margarita
(G. Bécard and Y. Piché, Appl. Environ. Microbiol. 55:2320-2325, 1989). Only the flavonols stimulated fungal growth. The flavones, flavanones, and isoflavones tested were generally inhibitory. Quercetin (10 μM) prolonged hyphal growth from germinated spores of
G. margarita
from 10 to 42 days. An average of more than 500 mm of hyphal growth and 13 auxiliary cells per spore were obtained. Quercetin also stimulated the growth of
Glomus etunicatum.
The glycosides of quercetin, rutin, and quercitrin were not stimulatory. The axenic growth of
G. margarita
achieved here under rigorously defined conditions is the most ever reported for a vesicular-arbuscular mycorrhizal fungus.
Cloning, sequence, and phenotypic expression of katA, which encodes the catalase of Lactobacillus sake LTH677
Authors: Knauf H J , Vogel R F , Hammes W P
Published: January 2020

Lactobacillus sake LTH677 is a strain, isolated from fermented sausage, which forms a heme-dependent catalase. This rare property is highly desirable in sausage fermentation, as it prevents rancidity and discoloration caused by hydrogen peroxide. A gene bank containing MboI fragments of chromosomal DNA from Lactobacillus sake LTH677 in Escherichia coli plasmid pBR328 was constructed. The catalase gene was cloned by heterologous complementation of the Kat- phenotype of E. coli UM2. The catalase structural gene, designated katA, was assigned to a 2.3-kb region by deletion analysis of the originally cloned fragment in plasmid pHK1000. The original chromosomal arrangement was determined by Southern hybridization. Protein analysis revealed that the catalase subunit has a molecular size of 65,000 Da and that the active catalase possesses a hexameric structure. The molecular size of the subunit deduced from the nucleotide sequence was determined to 54,504 Da. The N-terminal amino acid sequence of the 65,000-Da protein corresponded to the one deduced from the DNA sequence. After recloning of katA in the E. coli-Lactococcus shuttle vector pGKV210, the gene was successfully transferred and phenotypically expressed in Lactobacillus casei, which is naturally deficient in catalase activity.
Accumulation of Ergopeptide Alkaloids in Symbiotic Tall Fescue Grown under Deficits of Soil Water and Nitrogen Fertilizer
Authors: Arechavaleta M. , Bacon C. W. , Plattner R. D. , Hoveland C. S. , Radcliffe D. E.
Published: January 2020

The fungus
Acremonium coenophialum
is endophytically associated with tall fescue (
Festuca arundinacea
Schreber). Within this symbiotum the fungus produces ergopeptide alkaloids, which are associated with livestock toxicoses. Environmental effects on the production of ergot alkaloids within the symbiotum are unknown. We conducted a greenhouse study of the effects of flooding, nitrogen rate during fertilization (11, 73, and 220 mg of N per pot weekly), nitrogen form (3.4 and 34 mg of N as NH
4
+
or NO
3
-
per pot), and drought stress (-0.03, -0.05, and -0.50 MPa) on ergopeptide alkaloid concentrations in one genotype of nonsymbiotic and symbiotic tall fescue grown in plastic pots. It was determined that the concentration of ergovaline, the major type of ergopeptide alkaloid, was increased but was not as high as that in nonflooded controls. Total ergopeptide and ergovaline concentrations in plants receiving high (220 mg of N per pot) and low (11 mg of N per pot) levels of NH
4
NO
3
fertilization were not affected by flooding. The form of nitrogen was important since all concentrations of NO
3
-
-N increased ergopeptide alkaloid content, as opposed to the effects of NH
4
+
-N, which was effective only at high concentrations (34 mg of N per pot). Ergopeptide concentrations were highest in drought-stressed plants grown at -0.50 MPa and fertilized at the moderate or high N rate. The results suggest that within this genotype, ergopeptide alkaloid biosynthesis by the fungus is not appreciably affected by flooding but is greatly increased by high rates of N fertilization and moderate water deficit.