Alphatoxin Nanopore Detection of Aflatoxin, Ochratoxin and Fumonisin in Aqueous Solution.

Mycotoxins are toxic and carcinogenic metabolites produced by groups of filamentous fungi that colonize food crops. Aflatoxin B1 (AFB1), ochratoxin A (OTA) and fumonisin B1 (FB1) are among the most relevant agricultural mycotoxins, as they can induce various toxic processes in humans and animals. To detect AFB1, OTA and FB1 in the most varied matrices, chromatographic and immunological methods are primarily used; however, these techniques are time-consuming and expensive. In this study, we demonstrate that unitary alphatoxin nanopore can be used to detect and differentiate these mycotoxins in aqueous solution. The presence of AFB1, OTA or FB1 inside the nanopore induces reversible blockage of the ionic current flowing through the nanopore, with distinct characteristics of blockage that are unique to each of the three toxins. The process of discrimination is based on the residual current ratio calculation and analysis of the residence time of each mycotoxin inside the unitary nanopore. Using a single alphatoxin nanopore, the mycotoxins could be detected at the nanomolar level, indicating that alphatoxin nanopore is a promising molecular tool for discriminatory analysis of mycotoxins in aqueous solution.

Spondias tuberosa inner bark extract exert antidiabetic effects in streptozotocin-induced diabetic rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Diabetes mellitus (DM) is one of the most important medical emergencies of the 21st century. However, commercially available oral drugs with antidiabetic properties have been limited because of potential side effects, such as: hypoglycemia, weight gain, hepatic dysfunction and abdominal discomfort. As well as antidiabetic drugs, many types of medicinal herbal supplements are utilized as alternative treatments for DM and related comorbidities. Spondias tuberosa Arruda (Anacardiaceae), popularly known as "umbu", has been used in traditional medicine to treat a vast range of diseases, including DM, infections, digestive disorders, diarrhea and menstrual abnormalities. AIM OF THE STUDY: This study evaluated the effect of the hydroethanolic extract of the inner stem bark of Spondias tuberosa (EEStb) in streptozotocin-induced diabetic rats. MATERIALS AND METHODS: Diabetes was induced in rats by a single injection of STZ (40 mg/kg i.p.). Diabetic rats were treated with 250 mg/kg or 500 mg/kg of the EEStb for 21 days. Water intake, urinary volume, body weight, as well as biochemical parameters, such as cholesterol total (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), hepatic and muscle glycogen urea, alanine and aspartate aminotransferase, total protein, albumin, and glucose blood levels, were analyzed. We also determined the hepatic antioxidant state, as well as both of insulin and glucose tolerance. RESULTS: The extract was evaluated by HPLC, and the major components of EESTb were identified (i.e. gallic acid and quercetin). The 500 mg/kg dosage of EEStb significantly decreased fasting blood glucose and post-prandial glucose. The EEStb also reduced urinary volume, food and water intake, as well as decreased body weight gain. Diabetic rats that received EEStb had a lower loss of muscle mass and white adipose tissue. Additionally, EEStb improved the urinary excretion of urea and glucose. The extract significantly decreased triglycerides, total cholesterol and VLDL in diabetic rats. However, no significant effect was observed on the levels of total and HDL cholesterol. EEStb treatment prevented hepatotoxic diabetic-induced, improved GSH:GSSG ratio, SOD and CAT activity as well as reduced nitrite and TBARs levels. CONCLUSIONS: Our results demonstrate that EEStb has antioxidant and hepatoprotective effects as well as improves insulin sensibility in diabetic rats. This indicates that S. tuberosa could be a potential resource for alternative therapies in the treatment of hyperglycemic conditions. These results also support the use of EEStb in ethnomedicine for the management of diabetes.

Brain acetylcholinesterase of jaguar cichlid (Parachromis managuensis): From physicochemical and kinetic properties to its potential as biomarker of pesticides and metal ions.

This contribution aimed to characterize physicochemical and kinetic parameters of the brain cholinesterases (ChEs) from Parachromis managuensis and investigate the in vitro effects of pesticides and metal ions on its activity intending to propose as biomarker. This species is suitable for this investigation because (1) it was recently introduced in Brazil becoming invasive (no restrictions on capture) and (2) occupies the top of the food chain (being subject to bioaccumulation). The enzyme extract was exposed to 10 metal ions (Al(3+), Ba(2+), Cd(2+), Cu(2+), Hg(2+), Mg(2+), Mn(2+), Pb(2+), Fe(2+) and Zn(2+)) and ChEs selective inhibitors (BW284c51, Iso-OMPA, neostigmine and serine). The extract was also incubated with organophosphate (dichlorvos) and carbamate pesticides (carbaryl and carbofuran). Inhibition parameters (IC20, IC50 and ki) were determined. Selective inhibitors and kinetic parameters confirmed acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) -like as responsible for the ChE activities, most AChE. The IC50 values for pesticides were: 1.68µM (dichlorvos); 4.35µM (carbaryl) and 0.28µM (carbofuran). Most of the analyzed ions did not show significant effect at 1mM (p=0.05), whereas the following ions inhibited the enzyme activity in the order: Hg(2+)>Cu(2+)>Cd(2+)>Zn(2+). Mercury ion strongly inhibited the enzyme activity (IC20=0.7µM). The results about allow to conclude that P. managuensis brain AChE is a potential biomarker for heavy metals and pesticides under study, mainly for the carbamate carbofuran once it was capable to detect 6-fold lower levels than the limit concentration internationally recommended.