| ochratoxin a from a toxicological perspective. | ochratoxin a (ota) is a widespread mycotoxin which is produced mainly by the mould fungi aspergillus ochraceus and penicillum verrucosum during the storage of cereals, cereal products and other plant-derived products such as herbs, spices, grapes, etc. by carry over from mouldy fodder, ochratoxin a is also found in pork meat, offal and sausages containing pork blood. when ingested as a food contaminant, ota is very persistent in human beings with a blood half-life of 35 days after a single oral ... | 2000 | 10849253 |
| ochratoxin formation in aspergillus ochraceus with particular reference to spoilage of coffee. | production of ochratoxin on media by eight isolates of aspergillus ochraceus from coffee or its processing environment in india, indonesia, kenya, and brazil, and seven brazilian isolates from other commodities, has been compared with yields in shaken fermentation on shredded wheat and coffee (coffea arabica). shredded wheat most consistently allowed expression of biosynthesis of ochratoxins a and b in yields up to 3.5% of the dry product. culture on artificial media was an unreliable predictor ... | 2000 | 10857930 |
| molecular analysis of variability within the toxigenic aspergillus ochraceus species. | genetic variability of aspergillus ochraceus was examined at the dna level. based on the haeiii-bg/ii generated mitochondrial dna restriction profiles, most isolates could be classified into two distinct groups. these two groups could also be distinguished by the random amplified polymorphic dna technique, and with telomeric pcr amplifications. phylogenetic analysis of sequences of the intergenic transcribed spacer region of some of the strains resulted in a dendrogram with the same topology as ... | 2000 | 10932351 |
| synthesis and evaluation of some new fluorinated hydroquinazoline derivatives as antifungal agents. | the key intermediate octahydroquinazoline (1) was obtained in one pot synthesis by a modification of the biginelli reaction. compound 1 was allowed to react with phenacyl bromide and bromomalononitrile to furnish thiazolo[2,3-b]quinazoline 3 and 12, respectively. interaction of compound 12 with formamide, formic acid and phenyl isothiocyanate yielded the corresponding pyrimidino[4',5':4.5]thiazolo[2,3-b] quinazolines 13, 14 and 17, respectively. the structure of the synthesized compounds were el ... | 2000 | 10966155 |
| synthesis and antifungal activity of novel pyrano[2',3':4,5]thiazolo[2,3-b]quinazolines, pyrido[2',3':4,5]thiazolo[2,3-b]quinazolines and pyrazolo[2',3':4,5]thiazolo[2,3-b]quinazolines. | the starting materials thiazolo[2,3-b]quinazolines (5a,b) were obtained in one pot synthesis by treating octahydroquinazoline (2) with chloroacetic acid and aromatic aldehydes. thiazoloquinazoline (5) was reacted with ch2(cn)2/piperidine and ch2(cn)2/naoh (ch3oh), to furnish pyrano[2',3':4,5]thiazolo[2,3-b]quinazolines (6a,b) and pyrido[2',3':4,5]thiazolo[2,3-b]quinazoline (7), respectively. refluxing of 5a with nh2csnh2/koh and hydrazines in ethanol furnished the corresponding, [1,3]thiazino[4' ... | 2000 | 10966160 |
| susceptibility to secondary bacterial infections in growing pigs as an early response in ochratoxicosis. | mycotoxic nephropathy was induced in twelve 14 kg pigs fed a dietary component, moulded by aspergillus ochraceus and contributing ochratoxin a at 1 or 3 ppm for up to 3 weeks. concurrently, salmonellosis arose spontaneously in all six animals treated at 3 ppm and all died between days 15 and 17. two of the six pigs in the 1 ppm group died similarly but the rest, and all of six control animals, were unaffected. clinical biochemistry and histology revealed changes typical of renal ochratoxicosis i ... | 2000 | 10987179 |
| impact of environment and interspecific interactions between spoilage fungi and aspergillus ochraceus on growth and ochratoxin production in maize grain. | using layers of irradiated but still fertile maize grain, the effects of water activity (0.995, 0.95 a(w)) and temperature (18, 30 degrees c) on interspecific interactions between aspergillus ochraceus and five other spoilage fungi were examined. asp. ochraceus was not competitive against asp. flavus, asp. niger, or alternaria alternata at 18 degrees c when water was freely available (0.995 a(w)), while at 0.95 a(w) it was dominant against asp. candidus, asp. flavus and alt. alternata. at 30 deg ... | 2000 | 11028955 |
| [microbiological threat from buildings and rooms and its influence on human health (sick building syndrome)]. | in buildings we can observe many different strains of bacteria, over 400 species of mould fungi, many strains of fungus causing the rotting of wood and wood like materials, many species of algae, aphids, and other types of growths and seed plants and also over 30 types of mites especially those seen in house dust. buildings, especially their interiors have a very specific microclimate. within it areas of so called ecological lows are formed in which conditions for settlement, growth and reproduc ... | 2000 | 11109318 |
| circumdatin g, a new alkaloid from the fungus aspergillus ochraceus. | the crude extract of the broth of aspergillus ochraceus was found to inhibit the final stage of polyprotein processing during hepatitis c virus replication. bioassay-guided fractionation led to the isolation of the known compound mellein as the active component of the extract. also isolated were circumdatin f and a new alkaloid, circumdatin g. the structure of circumdatin g was determined by spectroscopic analysis. | 2001 | 11170686 |
| [the use of micromycetes for cleaning parts of aircraft]. | the mycelial fungi penicillium funiculosum, p. citrinum, p. expansum, p. chrysogenum, aspergillus ochraceus, a. alliaceus, a. luchaensis, a. flavus, and a. niger were isolated from enrichment cultures. these fungi actively destruct carbon deposits formed during exploitation of aircraft. a biotechnological method for removing fouling from parts of aircraft engines (pae) was developed. this method is less laborious, more rapid and ecologically clean than contemporary chemical methods. scanning mic ... | 2001 | 11234409 |
| total syntheses of the benzodiazepine alkaloids circumdatin f and circumdatin c. | total syntheses of circumdatin f and circumdatin c, which both possess a 3h-quinazolin-4-one as well as a 1,4-benzodiazepin-5-one moiety, are described. a tripeptide derivative was synthesized as a key intermediate and dehydrated to a benzoxazine by reaction with triphenylphosphine, iodine, and a tertiary amine. the natural products were attained via rearrangements to an amidine intermediate, deprotection with 45% hbr in acetic acid, and cyclization on silica gel. | 2001 | 11304202 |
| the entomopathogenic potential of aspergillus spp. in mosquitoes vectors of tropical diseases. | eleven strains of the most frequent aspergillus species found in a survey of brazilian mosquitoes collected in the states of minas gerais and rio de janeiro, brazil, were used for bioassays in second-stage larvae of aedes fluviatilis and culex quinquefasciatus. aspergillus ochraceus, a. kanagawaensis and one strain of a. sulphureus were most effective, causing mortality in at least 80% of the larvae of the two mosquito species tested. variations in entomopathogenic capacity were observed in the ... | 2001 | 11314246 |
| production of ochratoxin a by aspergillus carbonarius on coffee cherries. | robusta coffee cherries collected before and during sun drying from two coffee farms in thailand were examined for moulds producing ochratoxin a (oa). aspergillus ochraceus was only detected in one sample, whereas aspergillus carbonarius was isolated from 7 out of 14 samples. on gamma-irradiated coffee cherries, each of the six tested a. carbonarius strains produced oa. more than 4800 microg kg(-1) of toxin were detected under optimal conditions (25 degrees c, a(w) 0.99). oa production was stron ... | 2001 | 11322699 |
| replacements of amino acid residues at subsites and their effects on the catalytic properties of rhizomucor pusillus pepsin, an aspartic proteinase from rhizomucor pusillus. | site-directed mutagenesis was carried out to investigate the functional roles of amino acid residues of rhizomucor pusillus pepsin (rmpp) in substrate-binding and catalysis. mutations of two amino acid residues, e13 in the s3 subsite and n219 in the s3/s4 subsites, caused marked changes in kinetic parameters for two substrate peptides with different sequences. further site-directed mutagenesis at e13 suggested that e13 plays a critical role in forming the correct hydrogen bond network around the ... | 2001 | 11328603 |
| experimental mycotoxic nephropathy in pigs provoked by a diet containing ochratoxin a and penicillic acid. | mycotoxic nephropathy was induced in 18 young pigs by diets contaminated with strains of aspergillus ochraceus containing ochratoxin a (ota) and penicillic acid (pa) at levels corresponding to those naturally encountered in animal feeds in bulgaria. haematological and biochemical parameters, as well as the morphological and ultrastructural changes in various internal organs, and especially in the kidneys, were examined at different stages of development of the disease. a mottled surface of the k ... | 2001 | 11334150 |
| biosynthesis of diaporthin and orthosporin by aspergillus ochraceus. | diaporthin and orthosporin were characterised from the fungus aspergillus ochraceus d2306. diaporthin was identified by high-resolution electron impact mass spectrometry and 1h and 13c nmr spectroscopy, from which new spectroscopic assignments were made. orthosporin was also identified by mass spectrometry and both fungal metabolites are reported for the first time as co-metabolites and also as products of a. ochraceus. the methylation inhibitor ethionine affected production of both diaporthin a ... | 2001 | 11382231 |
| current importance of ochratoxin a-producing aspergillus spp. | ochratoxin a (oa) is receiving attention worldwide because of the hazard it poses to human and animal health. oa contamination of commodities, such as cereals or pork and poultry meat, is well recognized. nevertheless, there is an increasing number of articles reporting oa contamination in other food commodities, such as coffee, beer, wine, grape juice, and milk, in the last few years. this continuous and increasing exposure to oa that humans experience is reflected in the high incidence of oa i ... | 2001 | 11403149 |
| isolation of milk-clotting enzyme from transgenic sheep milk and its comparison with calf chymosin. | technology for preparation of chymosin from milk of transgenic sheep has been elaborated. purification of the preparation by ion-exchange chromatography on aminosilochrom and biospecific chromatography on bacitracin-sepharose yielded homogeneous active enzyme. hydrolysis of protein substrates (hemoglobin, bsa, and sodium caseinate) by the transgenic sheep chymosin and stability of the enzyme at various values of ph were studied. judging by the amino acid composition, the n-terminal sequence invo ... | 2001 | 11403643 |
| aspartame prevents the karyomegaly induced by ochratoxin a in rat kidney. | ochratoxin a (ota) is a mycotoxin produced by aspergillus ochraceus as well as other moulds. this mycotoxin contaminates animal feed and food. ota is immunosuppressive, genotoxic, teratogenic, carcinogenic and is nephrotoxic in all animal species studied so far. ota inhibits protein synthesis and induces lipid peroxidation. since it seems impossible to avoid completely contamination of foodstuffs by toxigenic fungi, it is necessary to investigate the possible ways of limiting such toxicity. an a ... | 2001 | 11409539 |
| isolation and bioactivities of constitutents of the roots of garcinia atroviridis. | two new prenylated compounds, the benzoquinone atrovirinone (1) and the depsidone atrovirisidone (2), were isolated from the roots of garcinia atroviridis. their structures were determined on the basis of the analysis of spectroscopic data. while compound 2 showed some cytotoxicity against hela cells, both compounds 1 and 2 were only mildly inhibitory toward bacillus cereus and staphylococcus aureus. | 2001 | 11473441 |
| occurrence of ochratoxin a-producing fungi in raw brazilian coffee. | ochratoxin a (oa)-producing fungi were identified in coffee at different stages of maturation. the toxin was quantified in coffee during terrace drying and in coffee stored in barns. by direct plating, a high level of contamination (100%) was found in the coffee beans studied, with the genus aspergillus representing 33.2%, of which aspergillus ochraceus and aspergillus niger represented 10.3 and 22.9%, respectively, of the strains isolated from the coffee beans. the capacity to produce ochratoxi ... | 2001 | 11510665 |
| extreme dryness and dna-protein cross-links. | exposure of fungal conidia (aspergillus ochraceus) or spores of bacillus subtilis to extreme dryness or vacuum induces dna lesions, including strand breaks and the formation of dna-protein cross-links. in wet cells only a small amount of protein is bound to dna, but exposure to conditions of lowered water activity results in an increasing number of cross-links between dna and proteins. in fungal conidia these cross-links are detected after selective iodination (125 j) of the dna-bound proteins f ... | 1992 | 11538147 |
| biochemical constraints for survival under martian conditions. | a wide variety of terrestrial organisms, the so-called "anhydrobiotes," has learned to survive in a state of extreme dehydration in dry environments. strategies for survival include the accumulation of certain polyols and nonreducing saccharides, which help to prevent damage to membranes and proteins, but at low water partial pressure dna is also progressively damaged by various lesions, including strand breaks and cross-linking to proteins. these lesions, if they are not too numerous, can be ... | 1995 | 11539226 |
| ochratoxin a in airborne dust and fungal conidia. | farm workers are often exposed to high concentrations of airborne organic dust and fungal conidia, especially when working with plant materials. the purpose of this investigation was to study the possibility of exposure to the mycotoxin ochratoxin a (ota) through inhalation of organic dust and conidia. dust and aerosol samples were collected from three local cowsheds. aerosol samples for determination of total conidia and dust concentrations were collected by stationary sampling on polycarbonate ... | 2001 | 11554583 |
| microbiological oxygenation of bridgehead azabicycloalkanes. | a series of n-substituted bridgehead azabicycloalkanes has been prepared and examined as substrates for microbiological oxygenation using the fungi beauveria bassiana, rhizopus nigricans, aspergillus ochraceus, and rhizopus arrhizus. oxygenation using b. bassiana of n-tosyl-7-azabicyclo[2.2.1]heptane gave n-[p-(hydroxymethyl)benzenesulfonyl]-7-azabicyclo[2.2.1]heptane (56% yield), of n-(phenyloxycarbonyl)-7-azabicyclo[2.2.1]heptane gave the 2-endo-ol (56% yield, 51% ee), of n-boc-7-azabicyclo[2. ... | 1997 | 11671535 |
| biosynthesis of ochratoxins by aspergillus ochraceus. | shaken liquid fermentation of an isolate of aspergillus ochraceus showed growth-associated production of ochratoxins a and b, followed by production of a related polyketide diaporthin. later, between 150 and 250 h, mellein accumulated transitorily. in contrast, shaken solid substrate (shredded wheat) fermentation over 14 days produced mainly ochratoxins a and b (ratio ca. 5:1) in very high yield (up to 10 mg/g). in these systems experiments with 14c-labelled precursors and putative intermediates ... | 2001 | 11672735 |
| circumdatin a, b, and c: three new benzodiazepine alkaloids isolated from a culture of the fungus aspergillus ochraceus. | | 1999 | 11674237 |
| purification and characterization of an invertase produced by aspergillus ochraceus ts. | purification and characterization of an extracellular invertase produced by aspergillus ochraceus ts are reported. the enzyme was purified (42-fold) from culture filtrate by salt precipitation, ion-exchange and gel filtration. sodium dodecyl sulphate polyacrylamide gel electrophoresis (sds-page) of the purified enzyme showed a single band of molecular mass 66 kda. the molecular mass of the native enzyme was found to be 130 kda by gel filtration. the purity of the protein was also checked against ... | 2001 | 11693382 |
| production of intracellular milk-clotting enzyme in submerged cultures of fusarium subglutinans. | fusarium subglutinans (wollenweber and reinking) nelson et al. was found to produce intracellular milk-clotting enzyme (mce) with good milk-clotting activity (mca). the crude activity of the produced enzyme was recorded as optimum at 55 degrees c and ph 4.5. the highest yield i.e. 78.43 su/mg dry biomass was obtained after 4 days of rotary shaking at 30 degrees c when the fermentation medium containes wheat flour 2%, glucose 1% and (nh4)2so4 0.1% with an initial ph value 6.0. under these conditi ... | 2001 | 11720308 |
| [isolation, purification, and separation of the complex preparation of extracellular proteinases with fibrinolytic and anticoagulant properties from aspergillus ochraceus 513]. | the extracellular proteinase complex of the microscopic fungus aspergillus ochraceus 513 was isolated, purified, and separated by affinity chromatography on bacillichin-silochrom and subsequent column chromatography on deae-toyopearl 650 m. the extracellular enzyme of the protein c activator type had a molecular mass of 36.5 kda and activity close to that of the agkistrodon snake venom protein c activator. the fibrinolytic and anticoagulant activities of the enzyme were investigated. | 2001 | 11763777 |
| relationship of mould count, ergosterol and ochratoxin a production. | the relationship between viable mould count, ergosterol content and ochratoxin a (oa) formation was studied at different inoculum concentrations of aspergillus ochraceus nrrl 3174 and penicillium verrucosum nrrl 3260 grown on sterile long-grain enriched white rice as the substrate. ergosterol was determined by extraction, saponification and quantification using high performance thin layer chromatography (hptlc) with uv detection. ergosterol and ochratoxin a were detected after 3 days of incubati ... | 2001 | 11764889 |
| a new antibiotic cj-17,665 from aspergillus ochraceus. | a new antibiotic, cj-17,665 (i) was isolated from the fermentation broth of aspergillus ochraceus, cl41582. it inhibits growth of multi-drug resistant staphylococcus aureus, streptococcus pyogenes, and enterococcus faecalis, with mics of 12.5, 12.5 and 25 microg/ml, respectively. the structure contains a diketopiperazine and an indole n-oxide moiety that is unusual in natural products. | 2001 | 11827033 |
| [preparations of extracellular proteinases from aspergillus ochraceus 513 and aspergillus alliaceus 7dn1]. | preparations of extracellular proteolytic enzymes with high anticoagulant activity resembling protein c activators were isolated from the culture liquids of aspergillus ochraceus 513 and aspergillus alliaceus 7 dn1 by precipitation with ammonium sulfate and subsequent purification from ammonium ions by gel filtration on a column with sephadex g-25. the ph and temperature activity optima and stability of the proteolytic enzymes from a. ochraceus 513 and a. alliaceus 7 dn1 were determined. | 2002 | 11910808 |
| effect of processing on ochratoxin a (ota) content of coffee. | coffee production can be roughly separated into three main steps 1) cherry processing to green coffee beans, 2) storage and transportation of green coffee to the place of consumption, and 3) green coffee processing to roasted and ground coffee and soluble coffee. the mold species which are known to produce ochratoxin a (ota) in coffee have been identified as aspergillus ochraceus, a. carbonarius and occasionally, a. niger. the length of time spent at a water activity > 0.80 at any moment until r ... | 2002 | 11922086 |
| experimental one year ochratoxin a toxicosis in pigs. | mild mycotoxic nephropathy was induced in 6 pigs by a diet containing ochratoxin a at 800 ppb, several times higher than that naturally encountered in some feed for pig production in bulgaria. the nephropathy was expressed only as slightly hypertrophied kidneys with a faintly mottled surface, discernible at the end of the experiment to a skilled observer but probably not recognisable in routine slaughterhouse processing. histological examination showed two types of changes: degenerative - affect ... | 2002 | 11926291 |
| ochratoxin production by the aspergillus ochraceus group and aspergillus alliaceus. | ochratoxin a is a toxic and carcinogenic fungal secondary metabolite; its presence in foods is increasingly regulated. various fungi are known to produce ochratoxins, but it is not known which species produce ochratoxins consistently and which species cause ochratoxin contamination of various crops. we isolated fungi in the aspergillus ochraceus group (section circumdati) and aspergillus alliaceus from tree nut orchards, nuts, and figs in california. a total of 72 isolates were grown in potato d ... | 2002 | 11976104 |
| [in vitro studies into the influence of ochratoxin a on the production of tumor necrosis factor alpha by the human monocytic cell line thp-1]. | the influence of pure ota and an aspergillus-ochraceus crude toxin on the intracellular expression and the secretion of tumor necrosis factor (tnf) alpha by the monocytic cell line thp-1 was studied in vitro. after 4 hours exposure, the secretion of tnf alpha was inhibited to 50% by pure ota in a concentration of 400 ng/ml and by crude toxin in a concentration of 100 ng/ml. the same concentrations of mycotoxins impaired the mitochondrial activity of thp-1 cells only marginally. the intracellular ... | 2002 | 11998373 |
| research on the origin, and on the impact of post-harvest handling and manufacturing on the presence of ochratoxin a in coffee. | the major risk factors and processing steps that can lead to contamination of green coffee with ochratoxin a (ota) have been identified. surveys of the green coffee production chain indicate that aspergillus ochraceus and a. carbonarius are the most potent ota producers on coffee. both have been successfully grown in vitro on green coffee and coffee cherries, respectively, producing high amounts of ota (5-13 mg kg(-1)). the so-called dry processing of coffee, which is cherry drying, was identifi ... | 2002 | 12113660 |
| synthesis of some new thiazole derivatives. antifungal activity and ultrastructure changes of some mycotoxin producing fungi. | several new thiazoles 2-7,10-12; 2,3-diphenyl-5-(2-thienyl)imidazo[2,1-b]thiazole 8, 3,5-di-(2-thienyl)imidazo[2,1-b]thiazole 9 and 4-amino-2-imino-6-(2-thienyl)thiazolo[3,2-a] pyrimidine 13 and 6-(2-thienyl)-3h-thiazolo[3,2-a]pyrimidin-2,4-diones 14 have been synthesized. the prepared compounds were evaluated for their in-vitro antifungal activity, compared with tioconazol fungicide. the strong antifungal activity is elicited by compounds 5 and 8. the most active compound 5 was found to induce ... | 2002 | 12135158 |
| the synthesis of (+)-preussin and related pyrrolidinols by diastereoselective paternò-büchi reactions of chiral 2-substituted 2,3-dihydropyrroles. | the n-alkoxycarbonyl substituted 2,3-dihydropyrroles 3 and 8 are converted to 2-benzyl-3-pyrrolidinols by the paternò - büchi reaction followed by hydrogenolysis. since the addition of the photoexcited benzaldehyde at the unsaturated heterocycle proceeds in a syn fashion, the benzyl group at c-2 and the hydroxy group at c-3 of the product are cis oriented. the simple and facial diastereoselectivities of the paternò-büchi reaction were studied more closely and the relative configuration of the pr ... | 2000 | 11073254 |
| first total synthesis of aspinolide b, a new pentaketide produced by aspergillus ochraceus. | the first asymmetric total synthesis of aspinolide b (1), a new 10-membered lactone discovered by chemical screening methods in the cultures of aspergillus ochraceus, has been accomplished. the key steps included a selective felkin-type addition of tms-acetylene to aldehyde 3a and a nozaki-hiyama-kishi coupling reaction to build the required 10-membered ring. this synthesis confirmed the absolute stereochemistry of aspinolide b, established through helmchen's method and corrected its previously ... | 2000 | 10987921 |
| environmental factors and nutritional utilization patterns affect niche overlap indices between aspergillus ochraceus and other spoilage fungi. | the total number, and the type of c source utilized in common by an ochratoxin producing strain of aspergillus ochraceus and six other spoilage fungi varied with the range used (95, biolog gn plates, or 18 major c sources found in maize). the niche size and niche overlap index (noi) were markedly influenced by water availability (water activity, aw) and temperature. with freely available water (0.995 aw) there was ecological similarity between a. ochraceus, a. alternata, a. candidus and a. flavu ... | 1999 | 10212444 |
| effect of water activity and temperature on growth and ochratoxin production by three strains of aspergillus ochraceus on a barley extract medium and on barley grains. | aspergillus ochraceus wilhelm is a widespread storage fungus that has been isolated from grains such as barley. the objective of this study was to determine the effects of water activity (a(w)), temperature, time and their interactions on (a) growth on a barley extract agar medium, (b) growth on barley grains and (c) ochratoxin production on barley grains by three strains of a. ochracieus. for the three a. ochreceus isolates examined (nrrl 3174, 3.113 and 3.38), optimal a(w) levels for growth on ... | 1998 | 9849791 |
| 6-l-alanineferrirubin, a ferrichrome-type siderophore from the fungus aspergillus ochraceous. | the molecular structure of 6-l-alanineferrirubin tetradecahydrate, [fe(c41h64n9o16)].14h2o, has been determined in order to confirm its chemical structure. the structural results show that the presence of an alanine in place of a serine or a glycine at position 6 in the cyclic hexapeptide has very little effect on the conformation of the 18-membered ring or on the geometry of the octahedral iron coordination. | 1997 | 9208459 |
| metabolites of ochratoxins in rat urine and in a culture of aspergillus ochraceus. | we studied the metabolic profile of ochratoxin a (oa) in rats and in a culture of oa-producing aspergillus ochraceus. ochratoxin alpha (o alpha), ochratoxin beta (o beta), 4-r-hydroxyochratoxin a (4-r-oh oa), 4-r-hydroxyochratoxin b (4-r-oh ob), and 10-hydroxyochratoxin a (10-oh oa) were isolated from a culture of a. ochraceus and structurally characterized by 1h nuclear magnetic resonance spectroscopy, mass spectrometry and high-pressure liquid chromatography. 4-r-oh oa and o alpha were consist ... | 1996 | 8593066 |
| 11 alpha-hydroxylation of progesterone in biphasic media using alginate-entrapped aspergillus ochraceus gel beads coated with polyurea. | a novel cell-immobilization technique was developed in this study for increasing substrate partition to the gel matrix by coating a polyurea thin layer on the surface of ca-alginate beads. the proposed method was simple and could be performed under mild conditions. the bioconversion of progesterone to 11 alpha-hydroxyprogesterone with these polyurea-coating alginate-entrapped aspergillus ochraceus cells was investigated using different organic solvents in biphasic media. the reaction medium of e ... | 1994 | 7764887 |
| [analysis of the metabolism of ochratoxin a-producing aspergillus ochraceus]. | | 1982 | 7171042 |
| mycotoxins in cereal grain. part 5. changes of cereal grain biological value after ammoniation and mycotoxins (ochratoxins) inactivation. | ammoniation was proved to be a suitable detoxification procedure to remove toxicity of aspergillus ochraceus mycotoxins (mainly ochratoxin a) from contaminated cereal grain (corn, wheat and barley). it was found that ammoniation should be performed to achieve decomposition of ochratoxin a to nondetectable level. ammoniated grain can be used as feedstuff component without essential change of nutritive value during ammoniation. | 1982 | 7070490 |
| preparation and some chemical characteristics of milk-clotting protease from bacillus mesentericus 76. | pure milk-clotting protease (mcp-76) is isolated by isotachophoresis at ph 5.0. the native molecule has only one protein chain. it is a metaloenzyme containing zinc. the pure mcp-76 has a molecular weight of 33 000 (+/- 1500) and by diphenyl-indenonyl-isothiocyanate method showed arginine as n-terminal amino acid. | 1981 | 7014483 |
| ochratoxin production by aspergillus ochraceus as affected by methionine and structurally related compounds. | when 10(-2) m of l- or d-methionine was added to a synthetic medium containing xylose as the sole carbon source, ochratoxin production by aspergillus ochraceus was strongly inhibited. at that concentration methionine derivatives, e.g., alpha-methyl-dl-methionine, dl-methionine sulfoxide, and l-methionine sulfone, did not inhibit ochratoxin production, whereas dl-methionine s-methyl sulfonium chloride (mmsc) inhibited ochratoxin production to a large extent. l-methionine, as well as mmsc, also co ... | 1983 | 6883217 |
| tunicamycin treatment inhibits the antiviral activity of interferon in mice. | earlier we reported that tunicamycin (tm) treatment of l cells in vitro significantly enhances the antiviral activity of interferon (ifn) against viruses (such as vesicular stomatitis, sindbis, and herpes simplex) which bud from membranes. however, no such enhancement of the antiviral activity of ifn by tm was observed against encephalomyocarditis virus (emcv) (nonbudding). we were interested to know whether tm would similarly enhance the antiviral activity of ifn and ifn inducers in vivo agains ... | 1983 | 6190759 |
| production of ochratoxins in different cereal products by aspergillus ochraceus. | the effects of temperature and length of incubation on ochratoxin a production in various substrates were studied. the optimal temperature for toxin production by aspergillus ochraceus nrrl-3174 was found to be around 28 c. very low levels of ochratoxin a are produced in corn, rice, and wheat bran at 4 c. the optimal time for ochratoxin a production depends on the substrate, ranging from 7 to 14 days at 28 c. ochratoxin b and dihydroisocoumaric acid, i.e., one of the hydrolysis products of ochra ... | 1971 | 5564676 |
| mycotoxicity of aspergillus ochraceus to chicks. | five isolates of aspergillus ochraceus, obtained from peanuts, were grown separately on sterile, moist corn for 14 days and fed to 1-day-old babcock b-300 cockerels to evaluate their toxic effects. two isolates were highly toxic, causing death of all birds during the 1st week of the experiment. two isolates were moderately toxic, causing severe growth suppression with some deaths occurring throughout the 3-week test period. one isolate had no apparent effect. when the two most toxic isolates (di ... | 1970 | 5418941 |
| studies on the proteolysis of fibrinogen and fibrin by aspergillus ochraceus enzyme as compared to the action of plasmin. | | 1974 | 4134484 |
| [characterization of an alkaline protease form aspergillus ochraceus]. | | 1974 | 4134483 |
| microbiological diagnosis of suppurative keratitis in bangladesh. | experience in setting up an inexpensive microbiology laboratory in the bangladesh national society for the blind eye hospital and training complex at chittagong is presented, together with the results of a pilot study to identify organisms responsible in 33 consecutive cases of suppurative keratitis in the chittagong area of bangladesh. of the 33 cases 21 were positively identified by means of gram stain and/or culture. two-thirds of the responsible organisms were bacteria, and one-third were fu ... | 1987 | 3555609 |
| cloning and sequencing of a gene for mucor rennin, an aspartate protease from mucor pusillus. | the aspartate protease of mucor pusillus (mucor pusillus rennin; mpr) is a milk-clotting enzyme used in the cheese industry. the partial amino acid sequence of mpr was determined and oligonucleotide probes were synthesized for cloning of the mpr gene. a clone giving positive hybridization with the probes was selected from the cosmid library. sequencing of the cloned dna revealed an open reading frame of 1281 bp without introns which encodes 361 amino acids for the expected mpr with an nh2-termin ... | 1986 | 3534790 |
| effect of inducers on metabolism of benzo(a)pyrene in vivo and in vitro: analysis by high pressure liquid chromatography. | the characterisation of metabolites formed from benzo(a)pyrene (bp) by aspergillus ochraceus ts and effect of inducers on bp metabolism are reported. the high pressure liquid chromatographic profile of bp metabolites was similar to that of mammalian microsomes furnishing diols, quinones and phenols. the production of bp-4,5-dihydrodiol (k-region diol) by aspergillus ochraceus ts seems to be novel and provides first report on bp metabolism by eukaryotic fungi. in control, phenols and quinones wer ... | 1988 | 3415704 |
| changes during lactation in the renin-like enzyme concentration in rat luteal tissue. | the activity of a renin-like enzyme (rle) previously found in rat copora lutea was studied during lactation. luteal rle concentration significantly increased after delivery and reached a maximum on day 5 of lactation. plasmatic levels of prl and progesterone also increased through lactation. treatment with 2 bromo-alpha-ergocryptine, which diminished plasma prl and progesterone levels, enhanced luteal rle activity. therefore, the increase in luteal rle during lactation seems to be independent of ... | 1987 | 3321821 |
| l-657,398, a novel antifungal agent: fermentation, isolation, structural elucidation and biological properties. | l-657,398 is a broad spectrum antifungal agent isolated from solid fermentation or from the mycelium of the liquid fermentation of aspergillus ochraceus. structurally, the compound is a novel pyrollidine related to anisomycin. | 1988 | 3209471 |
| effect of oil extracted from some medicinal plants on different mycotoxigenic fungi. | essential oils of 12 medicinal plants were tested for inhibitory activity against aspergillus flavus, a. parasiticus, a. ochraceus and fusarium moniliforme. the oils of thyme and cinnamon (< or = 500 ppm), marigold (< or = 2000 ppm), spearmint, basil, quyssum (3000 ppm) completely inhibit all the test fungi. caraway was inhibitory at 2000 ppm against a. flavus, a. parasiticus and 3000 ppm against a. ochraceaus and f. moniliforme. a. flavus, a. ochraceus, a. parasiticus and f. moniliforme were co ... | 2002 | 12176092 |
| on ochratoxin a and fungal flora in polish cereals from conventional and ecological farms. part 2: occurrence of ochratoxin a and fungi in cereals in 1998. | over 200 samples of polish cereal grain from the 1998 harvest obtained from conventional and ecological farms were investigated for the presence of ochratoxin a and for contamination by microscopic fungi. the frequency of contamination of rye and barley grains from conventional and ecological farms was similar in most cases; it varied from nearly 5 to 12%, respectively, for both types of farming. however, in samples from ecological farms, higher maximum concentrations of ochratoxin a were observ ... | 2002 | 12456276 |
| detection of ochratoxin a in animal feeds and capacity to produce this mycotoxin by aspergillus section nigri in argentina. | ochratoxin a (oa) is a mycotoxin detected in a variety of food and feeds mostly from countries with a temperate climate because of the fungi that produce it, mainly aspergillus ochraceus and penicillium verrucosum. in argentina, there is no available information about the natural occurrence of oa and ochratoxigenic fungi from feedstuffs. the aim was to evaluate the natural occurrence of oa in poultry, pig and rabbit feeds over 8 months. likewise, the capacity to produce oa by aspergillus section ... | 2002 | 12456278 |
| stephacidin a and b: two structurally novel, selective inhibitors of the testosterone-dependent prostate lncap cells. | two novel antitumor alkaloids, stephacidin a and b, were isolated from the solid fermentation of aspergillus ochraceus wc76466. both alkaloids exhibit in vitro cytotoxicity against a number of human tumor cell lines; however, stephacidin b demonstrated more potent and selective antitumor activities, especially against prostate testeosterone-dependent lncap cells with ic50 value of 60 nm. the structures of stephacidin a and b were established on the basis of the nmr data and x-ray crystallography ... | 2002 | 12465964 |
| sem study of water activity and temperature effects on the initial growth of aspergillus ochraceus, alternaria alternata and fusarium verticillioides on maize grain. scanning electron microscopy. | a scanning electron microscopy (sem) study of the effect of water activity (a(w)), temperature and fungal interactions on the very early phases of aspergillus ochraceus, alternaria alternata and fusarium verticillioides development on maize grains was carried out. germination and growth of individual fungal strains were assayed at 0.92, 0.95 and 0.98 a(w), and 20 and 30 degrees c. hyphal lengths were measured on micrographs taken by sem at different periods of incubation. a. alternata had the hi ... | 2003 | 12485744 |
| bilirubin dehydrogenase, an enzyme in aspergillus ochraceus ib-3 useful for diagnostic measurement of bilirubin. | bilirubin dehydrogenase, a membrane-bound enzyme that catalyzes the one-step oxidation of ditaurobilirubin and bilirubin to ditaurobiliverdin and biliverdin, respectively, in the presence of an electron acceptor, was found in aspergillus ochraceus ib-3, and purified from the membrane fraction through solubilization by triton x-100. phenazine and quinone derivatives acted as electron acceptors. accumulation of ditaurobiliverdin and biliverdin by enzyme catalysis increased the absorbance at 660 nm ... | 2002 | 12506975 |
| the source of ochratoxin a in brazilian coffee and its formation in relation to processing methods. | a total of 408 brazilian coffee samples was examined during the 1999 and 2000 coffee harvest seasons for the presence of ochratoxin a (oa) and fungi with the potential to produce it. samples came from four regions: alta paulista (western area of são paulo state), sorocabana (southwest são paulo state), alta mogiana (northeast são paulo state) and cerrado mineiro (western area of minas gerais state). cherries and beans were examined at different stages: immature, mature and overripe cherries from ... | 2003 | 12568757 |
| molecular typing of aspergillus ochraceus and construction of species specific scar-primers based on aflp. | 70 strains of aspergillus ochraceus mainly isolated from brazilian coffee related sources were investigated for genetic relatedness using automated laser fluorescence analysis of aflp fragments. cluster analysis of fingerprints revealed a very close relationship among most of the strains. based on these results, a sub-set of characteristic a. ochraceus strains was chosen for the detection of marker sequences. these sequences were obtained from silver stained aflps separated on polyacrylamide gel ... | 2003 | 12747422 |
| [ochratoxin a and human health]. | ochratoxin a (oa) is produced mainly by penicillium verrucosum, aspergillus ochraceus and a. carbonarius and it was found as a contaminant in the large number of agricultural commodities, feedstuffs and animal organs such as kidney and liver of pig. toxicological studies indicated that oa is a teratogenic, mutagenic and carcinogenic mycotoxin with the strong toxic effects on liver and kidney. in some endemic areas in the world, oa was suspected to be related to swine nephropathy and has been det ... | 2003 | 12793017 |
| [fungi growth in buildings]. | the results of research into occurrence of fungi in buildings are hereby presented. indoor air pollution balanced between 10(2)-10(3) cfu/m3. examined building surfaces have been found significantly mouldy. total number of fungi ranged from 3.28 x 10(5) to 9.75 x 10(10) cfu/100 cm2. the results of the research show the active development of this group of microorganisms. in rooms, over 30 fungi species belonging to 11 genera have been detected. the most frequently occurring ones were fungi genera ... | 2003 | 12870304 |
| continuous hydroxylation of progesterone by aspergillus ochraceus. | | 1961 | 13768046 |
| transformation of steroids by spores of microorganisms. i. hydroxylation of progesterone by conidia of aspergillus ochraceus. | conidia of aspergillus ochraceus convert progesterone into 11alpha-hydroxyprogesterone and 6beta, 11alpha-dihydroxyprogesterone. the conversion ability does not depend on the sporulation medium. transformation depends on the strain and on the conidia concentration. adaptation has never been observed. age and storage of conidia, ph, aeration-agitation, nitrogen source, metal ions, chelating agents, and metabolic activators showed no great influence within wide limits. mercuric chloride, p-chlorom ... | 1963 | 13996995 |
| on the mode of action of aspergillus ochraceus proteinase on oxidized insulin. | | 1964 | 14140993 |
| spoilage fungi and their mycotoxins in commercially marketed chestnuts. | a nationwide survey was carried out to assess mould spoilage of castanea sativa nuts sold in canadian grocery stores in 1998-99. morphological and cultural characters, along with secondary metabolite profiles derived from thin-layer chromatography, were used to sort and identify fungi cultured from nut tissue. three mycotoxigenic fungi dominated (penicillium crustosum, penicillium glabrum/spinulosum and penicillium discolor) and were isolated at frequencies of 67.1%, 18.6% and 17.7%, respectivel ... | 2003 | 14527787 |
| production and characterization of the milk-clotting protease of myxococcus xanthus strain 422. | the cheese industry is seeking novel sources of enzymes for cheese production. microbial rennets have several advantages over animal rennets. (1) they are easy to generate and purify and do not rely on the availability of animal material. (2) the production of microbial clotting enzymes may be improved by biotechnological techniques. in this work, the biochemical characterization of a novel milk-clotting extracellular enzyme from myxococcus xanthus strain 422 and a preliminary evaluation of its ... | 2003 | 14634834 |
| a polyketide synthase gene required for ochratoxin a biosynthesis in aspergillus ochraceus. | ochratoxin a is an important nephrotoxic and nephrocarcinogenic mycotoxin, produced by aspergillus ochraceus as a polyketide-derived secondary metabolite. a portion of a putative polyketide synthase gene (pks) involved in the biosynthesis of this mycotoxin was cloned by using a suppression subtractive hybridization pcr-based approach. the predicted amino acid sequence of the 1.4 kb clone shared 28-35 % identity to acyl transferase regions from fungal polyketide synthases found in the databases. ... | 2003 | 14663081 |
| bee pollen, a substrate that stimulates ochratoxin a production by aspergillus ochraceus wilh. | the capacity of bee pollen as a substrate for production of ochratoxin a (ota) by a strain of aspergillus ochraceus was studied. for control purposes corn, wheat and rice grains, and eleven liquid media were assayed. they were yeast extract sucrose broth (yes), yes supplemented with 0.05, 0.1, 0.5, 1 and 5% bee pollen, yes supplemented with 0.5% peptone, 50% must, wickerham medium, aflatoxin production medium and coconut broth medium. cultures were maintained at 28 degrees c for 4 weeks and were ... | 2004 | 15046315 |
| detection and quantification of aspergillus ochraceus in green coffee by pcr. | the aim of this study was to detect and quantify dna of the ochratoxinogenic fungus aspergillus ochraceus in green coffee and to compare the results with the ochratoxin a content of naturally contaminated samples. | 2004 | 15130140 |
| chemical constituents, antifungal and antioxidative effects of ajwain essential oil and its acetone extract. | gc and gc-ms analysis of ajwain essential oil showed the presence of 26 identified components which account for 96.3% of the total amount. thymol (39.1%) was found as a major component along with p-cymene (30.8%), gamma-terpinene (23.2%), beta-pinene (1.7%), terpinene-4-ol (0.8%) whereas acetone extract of ajwain showed the presence of 18 identified components which account for 68.8% of the total amount. the major component was thymol (39.1%) followed by oleic acid (10.4%), linoleic acid (9.6%), ... | 2004 | 15161185 |
| influence of residual milk-clotting enzyme on alpha(s1) casein hydrolysis during ripening of reggianito argentino cheese. | milk-clotting enzyme is considered largely denatured after the cooking step in hard cheeses. nevertheless, typical hydrolysis products derived from rennet action on alpha(s1)-casein have been detected during the ripening of hard cheeses. the aim of the present work was to investigate the influence of residual milk-clotting enzyme on alpha(s1)-casein hydrolysis in reggianito cheeses. for that purpose, we studied the influence of cooking temperature (45, 52, and 60 degrees c) on milk-clotting enzy ... | 2004 | 15202640 |
| ochratoxin a in conventional and organic cereal derivatives: a survey of the italian market, 2001-02. | ochratoxin a is a mycotoxin produced mainly by penicillium verrucosum and aspergillus ochraceus. although typically considered a cereal contaminant, it has also been detected in dried fruit, nuts, meat and derivatives. to estimate the quantity of ochratoxin a that might be ingested by italian consumers from these foods, 211 cereal derivatives (flours and bakery products) were analysed by high-performance liquid chromatography. products were from conventional and organic agriculture and from inte ... | 2004 | 15204537 |
| quantitative pcr analysis of house dust can reveal abnormal mold conditions. | indoor mold concentrations were measured in the dust of moldy homes (mh) and reference homes (rh) by quantitative pcr (qpcr) assays for 82 species or related groups of species (assay groups). about 70% of the species and groups were never or only rarely detected. the ratios (mh geometric mean : rh geometric mean) for 6 commonly detected species (aspergillus ochraceus, a. penicillioides, a. unguis, a. versicolor, eurotium group, and cladosporium sphaerospermum) were >1 (group i). logistic regress ... | 2004 | 15237292 |
| prediction of fungal growth and ochratoxin a production by aspergillus ochraceus on irradiated barley grain as influenced by temperature and water activity. | ochratoxin a (ota) is a secondary metabolite of aspergillus and penicillium species, including aspergillus ochraceus, a species that can be found in stored cereal grains such as barley. the objective of this study was to determine the effects of water activity (a(w), 0.80-0.99), temperature (10, 20, 30 degrees c), and a. ochraceus isolate differences on radial growth and ota production in irradiated barley grains. the three isolates showed optimal conditions for growth and ochratoxin a productio ... | 2004 | 15240077 |
| ecological determinants for germination and growth of some aspergillus and penicillium spp. from maize grain. | this study compared the effect of temperature (5-45 degrees c), water availability (water activity, aw; 0.995-0.75) and their interactions on the temporal rates of germination and mycelial growth of three mycotoxigenic strains of aspergillus ochraceus and one isolate each of a. flavus, a. niger, penicillium aurantiogriseum and p. hordei in vitro on a maize extract medium. germination was very rapid at > 0.90 aw with an almost linear increase with time for all species. however, at < 0.90 aw, the ... | 1998 | 15244054 |
| cloning and expression of clt genes encoding milk-clotting proteases from myxococcus xanthus 422. | the screening of a gene library of the milk-clotting strain myxococcus xanthus 422 constructed in escherichia coli allowed the description of eight positive clones containing 26 open reading frames. only three of them (clta, cltb, and cltc) encoded proteins that exhibited intracellular milk-clotting ability in e. coli, saccharomyces cerevisiae, and pichia pastoris expression systems. | 2004 | 15466588 |
| chemical composition and in vitro antimicrobial activities of the essential oils from endemic psiadia species growing in mauritius. | the composition of the leaf oils, obtained by hydrodistillation, of five endemic psiadia species of the asteraceae family were studied by gc/ms on both polar and non-polar columns. the analysis showed that the volatile components of the oils were made up essentially of monoterpenes, sesquiterpenes, aliphatics and other shikimic acid derivatives. with respect to the non-volatile components, great variations were observed: p. lithospermifolia contained (e)-isoasarone (51.5%); p. penninervia: eugen ... | 2004 | 15516729 |
| modelling of effects of water activity and temperature on germination and growth of ochratoxigenic isolates of aspergillus ochraceus on a green coffee-based medium. | influence of water activity (0.75-0.99 a(w)) and temperature (10, 20 and 30 degrees c) on germination and mycelial growth on green coffee extract agar medium of three ochratoxigenic isolates of aspergillus ochraceus was studied. optimal conditions for germination and growth were observed at 0.95-0.99 a(w) and 20-30 degrees c for the three isolates. minimum a(w) level for germination was 0.80, and 0.85 for mycelial growth. at marginal a(w) and temperature levels assayed, the lag phases prior to g ... | 2005 | 15617796 |
| ochratoxin a-induced dna damage in human fibroblast: protective effect of cyanidin 3-o-beta-d-glucoside. | ochratoxin a (ota), a mycotoxin produced by aspergillus ochraceus and other moulds, has recently received growing attention because of its carcinogenic, teratogenic and nephrotoxic properties in both humans and farm animals. nevertheless, with regard to the mechanism of toxicity, the data in the literature are inconclusive. the aim of our work was to verify in human fibroblasts treated with different ota dosages the involvement of oxidative pathway in the damage mechanism of this mycotoxin and t ... | 2005 | 15629238 |
| genetic relationships among brazilian strains of aspergillus ochraceus based on rapd and its sequences. | ochratoxin a (oa) is a mycotoxin that has been found in coffee beans and coffee beverages. its toxicological profile includes carcinogenicity, nephrotoxicity, and immunotoxicity. aspergillus ochraceus is the major species responsible for oa production in brazilian coffee beans. the genetic relationships among 25 a. ochraceus strains collected from brazilian coffee-bean samples were determined based on rapd and internal transcribed spacer (its) sequence data. the isolates were resolved into 2 dis ... | 2004 | 15644917 |
| circular dichroism analysis of destruxins from metarhizium anisopliae. | destruxins are secondary metabolites secreted by metarhizium anisopliae [y. kodaira, toxic substances to insects, produced by aspergillus ochraceus and oopsra destructor, agric. biol. chem., 25 (1961) 261-262. d.w. roberts, toxins from the entomogenous fungus metarhizium anisoplaie: isolation from submerged cultures, j. invertebr. pathol., 14 (1969) 82-88. d.w. roberts, toxins from the entomogenic fungi in microbial control of pest and plant disease, academic press, new york, 1981, pp441-464.]. ... | 2005 | 15656942 |
| effect of water activity and temperature on mycelial growth and ochratoxin a production by isolates of aspergillus ochraceus on irradiated green coffee beans. | aspergillus ochraceus as a fungal contaminant and ochratoxin a (ota) producer plays an important role in coffee quality. temperature and water activity (a(w)) significantly influence mycelial growth and ota production by isolates of a. ochraceus on green coffee beans. maximum mycelial growth was found at 30 degrees c and 0.95 to 0.99 a(w). a marked decrease in growth rate was observed when temperature and a(w) were reduced. at 0.80 a(w), mycelial growth occurred only at 30 and 20 degrees c for o ... | 2005 | 15690814 |
| volatile compounds of aspergillus strains with different abilities to produce ochratoxin a. | volatile compounds emitted by aspergillus strains having different abilities to produce ochratoxin a were investigated. thirteen strains of aspergillus ochraceus, three belonging to the a. ochraceus group, and eight other species of aspergillus were examined for their abilities to produce volatile compounds and ochratoxin a on a wheat grain medium. the profiles of volatile compounds, analyzed using spme, in all a. ochraceus strains, regardless of their toxeginicity, were similar and comprised ma ... | 2005 | 15740058 |
| determination of ochratoxin a in wine by liquid chromatography tandem mass spectrometry after combined anion-exchange/reversed-phase clean-up. | ochratoxin a (ota) is a mycotoxin produced by aspergillus ochraceus and penicillium verrucosum. it has been found and analysed in several foods and feeds. owing to its toxicity and occurrence in food and feed, the european community has issued directives and some countries have their own regulations for ota contents in food, feed and beverages. this work describes a method for the determination of ota in mulled and red wine. it is based on combined anion exchange/reversed-phase clean-up and was ... | 2005 | 15770471 |
| characterization and regulation of new secondary metabolites from aspergillus ochraceus m18 obtained by uv mutagenesis. | uv irradiation of aspergillus ochraceus nrrl 3174 conidia led to stable mutations in ochratoxin and penicillic-acid pathways. these mutants, especially m18, produced an unexpectedly large number of new metabolites. two new compounds were purified by tlc and hplc and their chemical structures were determined. they are 2,10-dimethyl 4-hydroxy-6-oxo-4-undecen-7-yne (1) and 4-(3-methyl-2- butenyl) oxy 1-phenyl acetic acid (2). compound 1 is very active against gram-positive bacteria, such as staphyl ... | 2005 | 15782235 |
| biotransformation and nephrotoxicity of ochratoxin b in rats. | ochratoxin b (otb), a secondary metabolite of aspergillus ochraceus, is the nonchlorinated analogue of the mycotoxin ochratoxin a (ota), which is one of the most potent renal carcinogens in rodents. despite the closely related structure, otb is considered to be of much lower toxicity. ota is poorly metabolized and slowly eliminated, and this may play an important role in ota toxicity, carcinogenicity, and organ specificity. since little is known regarding biotransformation and renal toxicity of ... | 2005 | 15963343 |
| pcr detection assays for the ochratoxin-producing aspergillus carbonarius and aspergillus ochraceus species. | two pcr assays have been developed to detect aspergillus carbonarius and aspergillus ochraceus, considered the main sources of ochratoxin a (ota) contaminating commodities, particularly grapes, coffee and derivatives, in warm climates. the species specific primers have been designed on the basis of its (internal transcribed spacers of rdna units) sequence comparisons obtained from aspergillus strains and have been tested in a number of strains from different origins and hosts. these pcr assays, ... | 2005 | 15967531 |
| two primer pairs to detect ota producers by pcr method. | fungi contaminating foods and feeds may produce many mycotoxins including ochratoxin a (ota). early and rapid detection of potential ota producing fungi is important to reduce the negative impacts of ota. in this study, two pcr specific primer pairs, aolc35-12l/aolc35-12r and aootal/aootar, were designed from a dna sequence of a polyketide synthase gene in aspergillus ochraceus nrrl 3174. on 14 different fungi tested by pcr, aolc35-12l/aolc35-12r amplified a unique band from either ota or citrin ... | 2005 | 15975678 |
| occurrence of mycotoxin producing fungi in bee pollen. | the natural mycobiota occurring in bee pollen is studied in the present report with special attention to analyze the incidence of fungal species that are potential producers of mycotoxins. a total of 90 ready-to-eat bee pollen samples were analyzed. eighty-seven samples were collected in stores placed in different spanish areas and three were from buenos aires (argentina). the statistical results (anova) showed that yeasts and penicillium spp. were the predominant fungi. with regard to the poten ... | 2005 | 16009441 |
| effect of the post-harvest processing procedure on ota occurrence in artificially contaminated coffee. | the purpose of this work was to study how the type of post-harvest process, i.e. natural preparation known as the dry method, and two wet processes, affected contamination and toxin production up to the green coffee stage. batches were contaminated with ochratoxin a or with ota-producing strains of aspergillus ochraceus and aspergillus niger. for ota artificial contamination, hulling or husk removal caused a reduction of ota. when a. ochraceus was inoculated at low level, its growth was hampered ... | 2005 | 16023238 |
| microfungi in cultivated fields in eskişehir provience (turkey). | the soil microfungi flora was investigated in four locations of eskişehir (turkey). 56 soil samples were seasonaly collected from 14 stations in the areas of karacahöyük, bahçecik, ogu i, and ogu ii. a total of 110 species belonging to 32 genera were encountered including absidia, acremonium, alternaria, aspergillus, beauveria, botryoderma, chaetomium, chrysosporium, cladosporium, eupenicillium, eurotium, fusarium, geotrichum, gliocladium, gonytrichum, metarrhizium, mucor, myrothecium, paecilomy ... | 2005 | 16028200 |