Hydrolysis of ochratoxin A by the microbial activity of digesta in the gastrointestinal tract of rats

1992 ◽  
Vol 23 (4) ◽  
Author(s):  
M.S. Madhyastha ◽  
R.R. Marquardt ◽  
A.A. Frohlich
Keyword(s):  
Gastrointestinal Tract ◽  
Microbial Activity ◽  
Ochratoxin A ◽  
Hydrolysis Of

scholarly journals Enzymatic hydrolysis of fumonisins in the gastrointestinal tract of broiler chickens

2017 ◽  
Vol 96 (12) ◽  
pp. 4342-4351 ◽  
Author(s):  
B Grenier ◽  
H E Schwartz-Zimmermann ◽  
C Gruber-Dorninger ◽  
I Dohnal ◽  
M Aleschko ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Enzymatic Hydrolysis ◽  
Broiler Chickens ◽  
Hydrolysis Of

scholarly journals In vitro assessment of gastrointestinal tract (GIT) fermentation in pigs: Fermentable substrates and microbial activity

2005 ◽  
Vol 54 (3) ◽  
pp. 191-201 ◽  
Author(s):  
Barbara A. Williams ◽  
Marlou W. Bosch ◽  
Ajay Awati ◽  
Sergey R. Konstantinov ◽  
Hauke Smidt ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Microbial Activity ◽  
In Vitro Assessment

Effect of a hay and a grain diet on the rate of hydrolysis of ochratoxin A in the rumen of sheep

1991 ◽  
Vol 69 (9) ◽  
pp. 3706-3714 ◽  
Author(s):  
H. Xiao ◽  
R. R. Marquardt ◽  
A. A. Frohlich ◽  
G. D. Phillips ◽  
T. G. Vitti
Keyword(s):  
Ochratoxin A ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

scholarly journals Association of Cellulytic Enzyme Activities in Eucalyptus Mulches with Biological Control of Phytophthora cinnamomi

2001 ◽  
Vol 91 (9) ◽  
pp. 847-855 ◽  
Author(s):  
A. J. Downer ◽  
J. A. Menge ◽  
E. Pond
Keyword(s):  
Microbial Activity ◽  
Enzyme Activities ◽  
Phytophthora Cinnamomi ◽  
Soil Depth ◽  
Soil Layers ◽  
Soil P ◽  
Fungal Populations ◽  
Hydrolysis Of ◽  
Vertical Transect

A series of samples were taken from mulched and unmulched trees starting at the surface of mulch or soil to a 15 cm soil depth, forming a vertical transect. Saprophytic fungi isolated from the soil samples on rose bengal medium and surveyed visually were most abundant in mulches and at the interface of mulch and soil (P < 0.05). Microbial activity as assayed by the hydrolysis of fluorescein diacetate was significantly greater in mulch layers than in soils. Cellulase and laminarinase enzyme activities were greatest in upper mulch layers and rapidly decreased in soil layers (P < 0.05). Enzyme activities against Phytophthora cinnamomi cell walls were significantly greater in mulch than in soil layers. When Phytophthora cinnamomi was incubated in situ at the various transect depths, it was most frequently lysed at the interface between soil and mulch (P < 0.001). Roots that grew in mulch layers were significantly less infected with Phytophthora cinnamomi than roots formed in soil layers. In mulched soil, roots were commonly formed at the mulch-soil interface where Phytophthora populations were reduced, whereas roots in unmulched soil were numerous at the 7.5 cm depth where Phytophthora cinnamomi was prevalent. Enzyme activities were significantly and positively correlated with each other, microbial activity, and saprophytic fungal populations, but significantly and negatively correlated with Phytophthora recovery.

scholarly journals New Insight into the Ochratoxin A Biosynthetic Pathway through Deletion of a Nonribosomal Peptide Synthetase Gene in Aspergillus carbonarius

2012 ◽  
Vol 78 (23) ◽  
pp. 8208-8218 ◽  
Author(s):  
Antonia Gallo ◽  
Kenneth S. Bruno ◽  
Michele Solfrizzo ◽  
Giancarlo Perrone ◽  
Giuseppina Mulè ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Biosynthetic Pathway ◽  
Nonribosomal Peptide Synthetase ◽  
Gene Encoding ◽  
Nonribosomal Peptide ◽  
Content Type ◽  
Peptide Synthetase ◽  
Ochratoxin Α ◽  
Hydrolysis Of ◽  
Insight Into

ABSTRACTOchratoxin A (OTA), a mycotoxin produced byAspergillusandPenicilliumspecies, is composed of a dihydroisocoumarin ring linked to phenylalanine, and its biosynthetic pathway has not yet been completely elucidated. Most of the knowledge regarding the genetic and enzymatic aspects of OTA biosynthesis has been elucidated inPenicilliumspecies. InAspergillusspecies, onlypksgenes involved in the initial steps of the pathway have been partially characterized. In our study, the inactivation of a gene encoding a nonribosomal peptide synthetase (NRPS) in OTA-producingA. carbonariusITEM 5010 has eliminated the ability of this fungus to produce OTA. This is the first report on the involvement of annrpsgene product in OTA biosynthetic pathway in anAspergillusspecies. The absence of OTA and ochratoxin α, the isocoumaric derivative of OTA, and the concomitant increase of ochratoxin β, the dechloro analog of ochratoxin α, were observed in the liquid culture of transformed strain. The data provide the first evidence that the enzymatic step adding phenylalanine to polyketide dihydroisocoumarin precedes the chlorination step to form OTA inA. carbonariusand that ochratoxin α is a product of hydrolysis of OTA, giving an interesting new insight into the biosynthetic pathway of the toxin.

scholarly journals Assessing the degradation of ochratoxin a using a bioassay: the case of contaminated winery wastewater

2007 ◽  
Vol 56 (2) ◽  
pp. 55-61 ◽  
Author(s):  
R. Nogueira ◽  
I. Estevinho ◽  
L. Abrunhosa ◽  
C. Mendonça ◽  
P. Machado ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Microbial Activity ◽  
Ochratoxin A ◽  
Experimental Work ◽  
Biomass Concentration ◽  
Biological Degradation ◽  
Batch Experiments ◽  
Wastewater Treatment Systems ◽  
Conventional Wastewater Treatment

In vineyards the presence of certain fungi may lead to the production of the mycotoxin ochratoxin A (OTA) and subsequent contamination of grapes and wine. Furthermore, winery wastewaters contaminated with OTA may represent an environmental hazard. Therefore, it is imperative to assess the fate of this mycotoxin in conventional wastewater treatment systems. The aim of the present work was to assess the biological degradation of OTA. Experimental work was carried out in batch experiments with initial OTA to biomass concentration ratios of 1.4 μg mg−1, 7.4 μg mg−1 and, 11.9 μg mg−1. The assays were inoculated with activated sludge biomass unadapted to the substance under examination. The proposed bioassay demonstrates that OTA concentrations up to 100 μg L−1 can be degraded by microbial activity in activated sludge.

scholarly journals Processing of vitamin A and E in the human gastrointestinal tract

2001 ◽  
Vol 280 (1) ◽  
pp. G95-G103 ◽  
Author(s):  
Patrick Borel ◽  
Berengere Pasquier ◽  
Martine Armand ◽  
Viviane Tyssandier ◽  
Pascal Grolier ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Vitamin A ◽  
Major Effect ◽  
Retinyl Palmitate ◽  
Human Gastrointestinal Tract ◽  
Gastric Emptying Rate ◽  
Fat Globules ◽  
Median Diameter ◽  
Duodenal Lumen ◽  
Hydrolysis Of

We aimed to provide basic data on the processing of vitamin A and E in the human gastrointestinal tract and to assess whether the size of emulsion fat globules affects the bioavailability of these vitamins. Eight healthy men received intragastrically two lipid formulas differing in their fat-globule median diameter (0.7 vs. 10.1 μm). Formulas provided 28 mg vitamin A as retinyl palmitate and 440 mg vitamin E as all- rac α-tocopherol. Vitamins were measured in gastric and duodenal aspirates, as well as in chylomicrons, during the postprandial period. The gastric emptying rate of lipids and vitamin A and E was similar. The free retinol/total vitamin A ratio was not significantly modified in the stomach, whereas it was dramatically increased in the duodenum. The proportion of ingested lipid and vitamins was very similar in the duodenal content. The chylomicron response of lipids and vitamins was not significantly different between the two emulsions. Our main conclusions are as follows: 1) there is no significant metabolism of vitamin A and E in the human stomach, 2) the enzyme(s) present in the duodenal lumen is significantly involved in the hydrolysis of retinyl esters, and 3) the size of emulsion fat globules has no major effect on the overall absorption of vitamin A and E.

scholarly journals Lipoamidase activity in normal and mutagenized pancreatic cholesterol esterase (bile salt-stimulated lipase)

1993 ◽  
Vol 291 (1) ◽  
pp. 65-69 ◽  
Author(s):  
D Y Hui ◽  
K Hayakawa ◽  
J Oizumi
Keyword(s):  
Enzyme Activity ◽  
Gastrointestinal Tract ◽  
Recombinant Protein ◽  
Human Milk ◽  
Bile Salt ◽  
Enzyme Kinetics ◽  
Cholesterol Esterase ◽  
Amide Hydrolysis ◽  
Ester Linkage ◽  
Hydrolysis Of

Purified human milk lipoamidase was digested with endoproteinase Lys-C and the digested peptides were subjected to gasphase microsequence analysis. The sequencing of three isolated peptides of human milk lipoamidase revealed the identity of this protein with human milk bile salt-stimulated lipase (pancreatic cholesterol esterase). The identity of the cholesterol esterase with lipoamidase was confirmed by expressing a recombinant form of rat pancreatic cholesterol esterase and testing for lipoamidase activity of the recombinant protein. The results showed that the recombinant cholesterol esterase displayed both lipolytic and lipoamidase activities and was capable of hydrolysing triacetin and lipoyl-4-aminobenzoate (LPAB). The mechanisms of the esterase and amidase activities of the enzyme were further tested by determining enzyme activity in a mutagenized cholesterol esterase with a His435-->Gln435 substitution. This mutation has been shown previously to abolish enzyme activity against esterase substrates [DiPersio, Fontaine and Hui (1991) J. Biol. Chem. 266, 4033-4036]. We showed that the mutagenized protein was effective in hydrolysing the amidase substrate LPAB and displayed similar enzyme kinetics to those of the native enzyme. These data indicate that the mechanism for the cholesterol esterase hydrolysis of lipoamides is different from that of the hydrolysis of substrates with an ester linkage. The presence of an enzyme in the gastrointestinal tract capable of both ester and amide hydrolysis suggests an important role for this protein in the digestion and absorption processes.

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