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use of biodiesel-derived crude glycerol for producing eicosapentaenoic acid (epa) by the fungus pythium irregulare.crude glycerol is a major byproduct for the biodiesel industry. producing value-added products through microbial fermentation on crude glycerol provides opportunities to utilize a large quantity of this byproduct. the objective of this study is to explore the potential of using crude glycerol for producing eicosapentaenoic acid (epa, 20:5 n-3) by the fungus pythium irregulare . when p. irregulare was grown in medium containing 30 g/l crude glycerol and 10 g/l yeast extract, epa yield and product ...200919265450
bacillus sp. l324-92 for biological control of three root diseases of wheat grown with reduced tillage.abstract strain l324-92 is a novel bacillus sp. with biological activity against three root diseases of wheat, namely take-all caused by gaeumannomyces graminis var. tritici, rhizoctonia root rot caused by rhizoctonia solani ag8, and pythium root rot caused mainly by pythium irregulare and p. ultimum, that exhibits broad-spectrum inhibitory activity and grows at temperatures from 4 to 40 degrees c. these three root diseases are major yieldlimiting factors for wheat in the u.s. inland pacific nor ...199718945111
amplified fragment length polymorphism analysis and internal transcribed spacer and coxii sequences reveal a species boundary within pythium irregulare.abstract pythium irregulare is a plant-pathogenic oomycete that causes significant damage to a variety of crops, including ornamentals and vegetables. morphological as well as molecular studies have reported high levels of genetic diversity within p. irregulare sensu lato which has raised the question as to whether it is a single species or is actually a complex of morphologically similar (cryptic) species. in this study, we used amplified fragment length polymorphism (aflp) fingerprinting and d ...200518943561
effect of application timing and method on efficacy and phytotoxicity of 1,3-d, chloropicrin and metam-sodium combinations in squash plasticulture.metam-sodium, 1,3-dichloropropene (1,3-d) and chloropicrin are widely used soil fumigants. combined application of metam-sodium and 1,3-d + chloropicrin is intended to improve efficacy and broaden spectrum of control, but little is known about the effect on crop safety. this study aimed to evaluate the effects of application timing of fumigant combinations on soilborne pest and disease control (nematodes, soil fungi and weeds) and growth of squash. two separate tests with chisel-injected and dri ...200818181144
pythium cryptoirregulare, a new species within the p. irregulare complex.pythium identification is based on several characteristics with considerable variation, particularly in pythium irregulare buis. as currently recognized. thirty-one isolates of pythium irregulare buis. from various hosts and geographic regions were compared by genetic analysis of multiloci dna fingerprints, sequence analysis of nuclear and mitochondrial genes and morphological and growth rate studies. previous research indicated two distinct groupings within the species, p. irregulare sensu stri ...200717682782
endogenous peptide defense signals in arabidopsis differentially amplify signaling for the innate immune response.atpep1, a 23-aa peptide encoded by arabidopsis propep1, a member of a small, six-member gene family, activates expression of the defense gene pdf1.2 (encoding defensin) and its own precursor gene, propep1, through the jasmonate/ethylene signaling pathway, mediated by a cell-surface receptor, pepr1. overexpression of two family members, propep1 and propep2, enhances resistance of arabidopsis plants against the pathogen pythium irregulare, and propep2 and propep3 are expressed at highly elevated l ...200717566109
aba is an essential signal for plant resistance to pathogens affecting ja biosynthesis and the activation of defenses in arabidopsis.analyses of arabidopsis thaliana defense response to the damping-off oomycete pathogen pythium irregulare show that resistance to p. irregulare requires a multicomponent defense strategy. penetration represents a first layer, as indicated by the susceptibility of pen2 mutants, followed by recognition, likely mediated by erecta receptor-like kinases. subsequent signaling of inducible defenses is predominantly mediated by jasmonic acid (ja), with insensitive coi1 mutants showing extreme susceptibi ...200717513501
in vitro metabolism of ginsenosides by the ginseng root pathogen pythium irregulare.the role of ginseng saponins (ginsenosides) as modulators or inhibitors of disease is vague, but our earlier work supports the existence of an allelopathic relationship between ginsenosides and soilborne microbes. interestingly, this allelopathy appears to significantly promote the growth of the important ginseng pathogen, pythium irregulare while inhibiting that of an antagonistic non-pathogenic fungus, trichoderma hamatum. herein we report on the apparent selective metabolism of 20(s)-protopan ...200616242739
isolation and characterization of a delta5 fa desaturase from pythium irregulare by heterologous expression in saccharomyces cerevisiae and oilseed crops.by using the polymerase chain reaction approach with two degenerate primers targeting the heme-binding and the third histidine-rich motifs in microsomal carboxyl-directed desaturases, we identified a cdna pid5 from pythium irregulare encoding a delta5 desaturase. the substrate specificity of the enzyme was studied in detail by expressing pid5 in a yeast (saccharomyces cerevisiae) mutant strain, amy-2alpha, where ole1, a delta9 desaturase gene, is disrupted. the result revealed that the encoded e ...200212458621
an arabidopsis mutant defective in jasmonate response is allelic to the auxin-signaling mutant axr1.a screen for arabidopsis mutants that were insensitive to methyl jasmonate (meja) in an assay for seedling root growth yielded only alleles of previously isolated mutants jar1 and coi1, with one exception. mapping of the locus and morphological characterization of the new mutant suggested it might be allelic to axr1, which had not previously been reported to show resistance to meja. the f(1) from a cross of the new mutant with axr1-3 did not show complementation, confirming that these are the sa ...200212376653
high-level production of gamma-linolenic acid in brassica juncea using a delta6 desaturase from pythium irregulare.gamma-linolenic acid (gla), a nutritionally important fatty acid in mammals, is synthesized by a delta6 desaturase. here, we report identification of pid6, a new cdna from the oleaginous fungus, pythium irregulare, encoding a 459-amino acid protein that shares sequence similarity to carboxyl-directed desaturases from various species. expression of pid6 in yeast (saccharomyces cerevisiae) revealed that it converts exogenously supplied linoleic acid into gla, indicating that it encodes a delta6 fa ...200212011365
effect of cultural conditions on production of eicosapentaenoic acid by pythium irregulare.the effect of culture conditions upon lipid content and fatty acid composition of mycelia of pythium irregulare was investigated with particular attention to increasing the yield of 5,8,11,14,17-eicosapentaenoic acid (20:5; omega-3)(epa). all experiments were done by shake flask culture using a yeast extract + malt extract medium. the maximum growth rate was obtained at 25 degrees c, but maximum epa production was obtained at 12 degrees c. the highest epa production was 76.5 micrograms epa/ml 13 ...19911367900
pythium infection activates conserved plant defense responses in mosses.the moss physcomitrella patens (p. patens) is a useful model to study abiotic stress responses since it is highly tolerant to drought, salt and osmotic stress. however, very little is known about the defense mechanisms activated in this moss after pathogen assault. in this study, we show that p. patens activated multiple and similar responses against pythium irregulare and pythium debaryanum, including the reinforcement of the cell wall, induction of the defense genes chs, lox and pal, and accum ...200919551405
towards the production of high levels of eicosapentaenoic acid in transgenic plants: the effects of different host species, genes and promoters.eicosapentaenoic acid (epa, 20:5n-3) plays an important role in many aspects of human health. in our efforts towards producing high levels of epa in plants, we investigated the effects of different host species, genes and promoters on epa biosynthesis. zero-erucic acid brassica carinata appeared to be an outstanding host species for epa production, with epa levels in transgenic seed of this line reaching up to 25%. two novel genes, an 18-carbon omega3 desaturase (cpdesx) from claviceps purpurea ...201019582587
partial purification and characterization of three ginsenoside-metabolizing beta-glucosidases from pythium irregulare.the ginseng pathogen pythium irregulare is able to selectively metabolize the 20(s) protopanaxadiol ginsenosides rb1, rb2, rc, rd, and gypenoside xvii via extracellular glycosidases, leading to the formation and partial assimilation of ginsenoside f2. herein we have partially purified three ginsenoside-deglycosylating enzymes from p. irregulare culture filtrates, and provide preliminary characterization. a protocol involving acetone precipitation, chromatofocusing on pbe 94, gel filtration on se ...200919818460
harzianic acid, an antifungal and plant growth promoting metabolite from trichoderma harzianum.a trichoderma harzianum strain, isolated from composted hardwood bark in western australia, was found to produce a metabolite with antifungal and plant growth promoting activity. the structure and absolute configuration of the fungal compound, harzianic acid (1), were determined by x-ray diffraction studies. harzianic acid showed antibiotic activity against pythium irregulare, sclerotinia sclerotiorum, and rhizoctonia solani. a plant growth promotion effect was observed at low concentrations of ...200919894739
secondary metabolites produced by a root-inhabiting sterile fungus antagonistic towards pathogenic fungi.a sterile red fungus (srf) isolated from cortices of roots of both wheat (triticum aestivum cv. gamenya) and ryegrass (lolium rigidum cv. wimmera) was found to protect the hosts from phytopathogens and promote plant growth. in this work, the major secondary metabolites produced by this srf were analysed, and their antibiotic and plant-growth-promoting activities investigated.201020156309
specific protein regions influence substrate specificity and product length in polyunsaturated fatty acid condensing enzymes.we describe a condensing enzyme from pythium irregulare (pirelo) that shows highest activity on the 18-carbon, delta-6 desaturated fatty acids, stearidonic acid and gamma-linolenic acid. however, this enzyme is also capable of elongating a number of other fatty acids including the 20-carbon, delta-5 desaturated fatty acid eicosapentaenoic acid. surprisingly, a phytophthora infestans condensing enzyme (pinelo) with very high homology to pirelo did not show activity with 20-carbon fatty acids. a s ...201020397628
an endogenous peptide signal in arabidopsis activates components of the innate immune response.innate immunity is initiated in animals and plants through the recognition of a variety of pathogen-associated molecules that in animals are called pathogen-associated molecular patterns and in plants are called elicitors. some plant pathogen-derived elicitors have been identified as peptides, but peptide elicitors derived from the plant itself that activate defensive genes against pathogens have not been previously identified. here, we report the isolation and characterization of a 23-aa peptid ...200616785434
zmpep1, an ortholog of arabidopsis elicitor peptide 1, regulates maize innate immunity and enhances disease resistance.zmpep1 is a bioactive peptide encoded by a previously uncharacterized maize (zea mays) gene, zmpropep1. zmpropep1 was identified by sequence similarity as an ortholog of the arabidopsis (arabidopsis thaliana) atpropep1 gene, which encodes the precursor protein of elicitor peptide 1 (atpep1). together with its receptors, atpepr1 and atpepr2, atpep1 functions to activate and amplify innate immune responses in arabidopsis and enhances resistance to both pythium irregulare and pseudomonas syringae. ...201121205619
ginsenosides stimulate the growth of soilborne pathogens of american ginseng.ginseng saponins (ginsenosides) were isolated from soil associated with the roots of commercially grown american ginseng (panax quinquefolius l.), identified via lc-ms and quantified via analytical hplc. the ginsenosides, including f(11), rb(1), rb(2), rc, rd, re and rg(1), represented between 0.02 and 0.098% (average 0.06%) of the mass of the soil collected from roots annually between 1999 and 2002. the same ginsenosides were also isolated from run-off of undisturbed plants grown in pots in a g ...200312946424
Molecular analyses of Pythium irregulare isolates from grapevines in South Africa suggest a single variable species.The Pythium irregulare species complex is the most common and widespread Pythium spp. associated with grapevines in South Africa. This species complex has been subdivided into several morphological and phylogenetic species that are all highly similar at the sequence level [internal transcribed spacer (ITS) and cytochrome c oxidase (cox) regions]. The complex includes Pythium regulare and Pythium cylindrosporum, which are morphologically distinct, and P. irregulare sensu stricto (s.s.) and Pythiu ...201122115440
nonfeed application of rendered animal proteins for microbial production of eicosapentaenoic acid by the fungus pythium irregulare.rendered animal proteins are well suited for animal nutrition applications, but the market is maturing, and there is a need to develop new uses for these products. the objective of this study is to explore the possibility of using animal proteins as a nutrient source for microbial production of omega-3 polyunsaturated fatty acids by the microalga schizochytrium limacinum and the fungus pythium irregulare. to be absorbed by the microorganisms, the proteins needed to be hydrolyzed into small pepti ...201122010831
antimicrobial activity of o-carboranylalanine.functionalized polyhedral carboranes, including amino acid analogs, have unique physicochemical properties and are used as experimental anticancer agents. however, our current knowledge on their effect in nonmammalian biological systems is limited. we investigated the activity spectrum in vitro of o-carboranylalanine (o-cba), considered to be a highly lipophilic analog of phenylalanine, against representative plant pathogenic bacteria and fungi of various taxonomic position. the antibacterial ef ...199910707765
effects of fungal root pathogens on the population dynamics of biocontrol strains of fluorescent pseudomonads in the wheat rhizosphere.the influences of gaeumannomyces graminis var. tritici (which causes take-all of wheat), rhizoctonia solani ag-8 (which causes rhizoctonia root rot of wheat), pythium irregulare, p. aristosporum, and p. ultimum var. sporangiiferum (which cause pythium root rot of wheat) on the population dynamics of pseudomonas fluorescens 2-79 and q72a-80 (bicontrol strains active against take-all and pythium root rot of wheat, respectively) in the wheat rhizosphere were examined. root infection by either g. gr ...199116348532
pepr2 is a second receptor for the pep1 and pep2 peptides and contributes to defense responses in arabidopsis.pep1 is a 23-amino acid peptide that enhances resistance to a root pathogen, pythium irregulare. pep1 and its homologs (pep2 to pep7) are endogenous amplifiers of innate immunity of arabidopsis thaliana that induce the transcription of defense-related genes and bind to pepr1, a plasma membrane leucine-rich repeat (lrr) receptor kinase. here, we identify a plasma membrane lrr receptor kinase, designated pepr2, that has 76% amino acid similarity to pepr1, and we characterize its role in the percep ...201020179141
a tandem array of 5s ribosomal rna genes in pythium irregulare.the 5s ribosomal rna genes of the oomycete pythium irregulare exist in tandem arrays unlinked to the rdna repeat unit. a clone with a 9.2-kb insert containing an array of 5s genes was identified in a lambda genomic library and was characterized by restriction mapping and partial sequencing. the array consisted of 9 apparently identical 5s genes and their spacers in tandem, followed by a diverged 5s-like sequence that is likely to be a pseudogene. this gene arrangement, although almost universal ...19979074490
sequence analysis of duplicated actin genes in lagenidium giganteum and pythium irregulare (oomycota).southern analysis of genomic dna identified multiple-copy actin gene families in lagenidium giganteum and pythium irregulare (oomycota). polymerase chain reaction (pcr) protocols were used to amplify members of these actin gene families. sequence analysis of genomic coding regions demonstrated five unique actin sequences in l. giganteum (lg-ac1, 2, 3, 4, 5) and four unique actin sequences in p. irregulare (pi-ac1, 2, 3, 4); none were interrupted by introns. maximum parsimony analysis of the codi ...19948064873
a new species of pythium with ornamented oogonia: morphology, taxonomy, internal transcribed spacer region of its ribosomal rna, and its comparison with related species.pythium spiculum sp. nov. was isolated from soil samples taken in a vineyard in the burgundian region of france and from different locations in spain and portugal. the oomycete has spiny oogonia and does not sporulate readily. it resembles pythium mamillatum meurs, but has its own distinguishing characteristics. it also exhibits sickle-shaped as well as spherical appressoria which at times are associated with sex organs like those found in pythium abappressorium paulitz and pythium contiguanum p ...200616445762
serological relationships between pythium irregulare buisman and certain tomato cultivars. 19744408353
Activity of Meadowfoam ( Limnanthes alba ) Seed Meal Glucolimnanthin Degradation Products against Soilborne Pathogens.Meadowfoam ( Limnanthes alba L.) is a herbaceous winter-spring annual grown as a commercial oilseed crop. The meal remaining after oil extraction from the seed contains up to 4% of the glucosinolate glucolimnanthin. Degradation of glucolimnanthin yields toxic breakdown products, and therefore the meal may have potential in the management of soilborne pathogens. To maximize the pest-suppressive potential of meadowfoam seed meal, it would be beneficial to know the toxicity of individual glucolimn ...201122142246
effects of temperature and ph on growth and composition of pythium irregulare and pythium vexans. 19715548903
biological studies on 2,1-benzisothiazole derivatives. i. evaluation of antibacterial, antifungal and genotoxic activities of 1-acyl-3-acylimino-2,1-benzisothiazolines.the in vitro evaluation of antibacterial, antifungal and genotoxic activities of some 1-acyl-3-acylimino-2,1-benzisothiazolines is described. compounds 55, 58, 60 and 62 exhibited a selective antibacterial activity. compounds 1, 2, 30, 59 and 63 were active against botrytis cinerea, compounds 6, 20, 39 and 54 against pythium irregulare. dna-damaging activity in the bacillus subtilis rec-assay was demonstrated for compounds 45, 46, 54, 55, 57 and 61. by the salmonella-microsome assay, genotoxic a ...19902128452
jasmonate signaling mutants of arabidopsis are susceptible to the soil fungus pythium irregulare.jasmonic acid has properties of a plant hormone, including the induction of specific genes associated with plant defense. we previously described jar1-1, an arabidopsis jasmonate response mutant that exhibits reduced sensitivity to methyl jasmonate. we have further characterized this mutant and two new alleles; jar1-2 from a gamma irradiated population, and jar1-4 from a t-dna mutant population. seedling root growth in jar1-1 was equally insensitive to methyl jasmonate and jasmonic acid, indicat ...19989807813
characterization of two novel type i ribosome-inactivating proteins from the storage roots of the andean crop mirabilis expansa.two novel type i ribosome-inactivating proteins (rips) were found in the storage roots of mirabilis expansa, an underutilized andean root crop. the two rips, named me1 and me2, were purified to homogeneity by ammonium sulfate precipitation, cation-exchange perfusion chromatography, and c4 reverse-phase chromatography. the two proteins were found to be similar in size (27 and 27.5 kd) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and their isoelectric points were determined to be ...199910198104
fungal lipids. ii. effects of varying concentration of nitrogen in the medium and incubation period on the chemical composition of lipids of pythium irregulare buisman. 19734731671
pythium irregulare fermentation to produce arachidonic acid (ara) and eicosapentaenoic acid (epa) using soybean processing co-products as substrates.arachidonic acid (ara) and eicosapentaenoic acid (epa) were produced by pythium irregulare fungus using soybean cotyledon fiber and soy skim, two co-products from soybean aqueous processing, as substrates in different fermentation systems. parameters such as moisture content, substrate glucose addition, incubation time, and vegetable oil supplementation were found to be important in solid-state fermentation (ssf) of soybean fiber, which is to be used as animal feed with enriched long-chain polyu ...201223269636
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