Putovanje kroz interakcije proteinskih kinaza aktiviranih mitogenima i okratoksina A

Ochratoxin A (OTA) is a ubiquitous mycotoxin with potential nephrotoxic, carcinogenic, and cytotoxic action. It has been proposed that OTA might be involved in the development of Balkan endemic nephropathy, which is associated with an increased risk of urinary tract tumours, and of other forms of interstitial nephritis. Cell susceptibility to OTA mainly depends on mycotoxin concentrations, duration of exposure, and intracellular molecular and genetic context. OTA can affect a cell by stimulating or inhibiting certain signalling pathways such as mitogen-activated protein kinase (MAPK). Three major mammalian MAPKs have been described: extracellular signal-regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 MAPK. All MAPKs regulate diverse cellular programmes, but in most cases ERKs have been linked to cell survival, while JNKs, and p38 MAPKs have been implicated in cell death by apoptosis. This review looks into OTA-mediated MAPK activation and its effects.Okratoksin A (OTA) posvuda je prisutan mikotoksin za koji se smatra da je potencijalno nefrotoksičan i karcinogen, a može uzrokovati i smrt stanice. OTA se smatra mogućim uzročnikom balkanske endemske nefropatije koju karakterizira povećani rizik od razvoja tumora mokraćnog sustava te različitih drugih vrsta intersticijskog nefritisa. Osjetljivost stanice naspram OTA ovisi ponajprije o koncentraciji mikotoksina, vremenu izloženosti i o unutarstaničnome molekularnom i genskom sklopu. OTA može djelovati na stanicu tako što potiče ili inhibira određene signalne putove u stanici poput puta proteinskih kinaza aktiviranih mitogenima (MAPK). Tri glavne MAPK u sisavaca su proteinska kinaza regulirana izvanstaničnim signalima (ERK), kinaza koja fosforilira N-kraj transkripcijskog faktora c-Jun (JNK) i p38 MAPK. Svi članovi porodice MAPK reguliraju različite stanične programe, s time da ERK najčešće stimuliraju preživljavanje stanica, dok JNK i p38 MAPK najčešće uzrokuju umiranje stanica apoptozom. U ovome smo preglednom članku prikazali na koji način stanice odgovaraju na aktivaciju MAPK koju potiče OTA

Estimation of ochratoxin A in portuguese population: New data on the occurrence in human urine by high performance liquid chromatography with fluorescence detection

With increasing knowledge of the persistence of OTA in the food chain, exposure to this mycotoxin is a potential human health hazard to humans, and evaluating its presence in populations has become highly important.http://www.sciencedirect.com/science/article/B6T6P-4JXR90G-4/1/ae320edca66d234021aec8fcdd0203f

Method for homogeneous spotting of antibodies on membranes: application to the sensitive detection of ochratoxin A

Membrane-based dot immunoassays are now widely used in almost every branch of biology and medicine. However, the quality of the immobilized antigen or antibody spots on the membranes was found to be highly operator-dependent and spotting by conventional methods often leads to heterogeneous spot morphologies and deposition inconsistencies. To circumvent these problems, a spotting method has been developed which is based on focussed absorption of an applied antibody solution through an aqueous network of capillary channels formed between the membrane and a wetted absorbent body. The method does not require any equipment for creating vacuum and according to assay requirements highly homogeneous spots of uniform size, in the range of 0.8- to 9-mm diameter, can be obtained by varying the volume of the applied antibody solution. Spot intensities were sufficiently high even at high antibody dilutions. Immobilization of anti-ochratoxin A (anti-OA) antibody by this method gave 2-fold increased sensitivity in a competitive assay of the toxin compared to conventional spotting methods. The calculated CV of the colour intensity for spots of different sizes (0.8 to 9 mm) was between 4.5 and 1%. Application of this spotting technique has been demonstrated for detection of OA in wine and coffee samples with the elimination of matrix interferences in the same immunoassay system. This was achieved by selective removal of nonspecific interfering substances from the sample extract during the assay. The detection limit of OA in wine (1 μg L−1) and coffee (2.5 μg kg−1) obtained by the present new method is superior to values reported recently. Thus, the present new method will be highly useful for improved performance of membrane-based immunoassays in almost every branch of biology and medicine