Aflatoxins in food products consumed in Brazil: a preliminary dietary risk assessment.

A preliminary dietary exposure assessment for aflatoxins (AFs; AFB1, AFB2, AFG1 and AFG2) was conducted to evaluate the potential carcinogenic risks for the Brazilian population. AF concentration data in food were obtained from analysis reports issued by the Central Public Health Laboratory of the Federal District (LACEN-DF) and from published work. Food consumption and body weight (bw) data were obtained from a national survey conducted in 2008/2009. Cancer risks arising from exposure to aflatoxins were assessed using the carcinogenic potency of AFs estimated by the JECFA, and hepatitis B virus prevalence in the Brazilian population. Additionally, margins of exposure (MOE) were also calculated for the various scenarios investigated. A total of 942 food samples were analysed for AFs in the Federal District between 2002 and 2011 with 4.5% of them being positive for at least one aflatoxin (LOQ = 2 µg kg(-1)). The highest percentage of contamination was found in peanuts (8.1%) and Brazil nuts (6.0%), with mean levels ranging from 6.7 µg kg(-1) in peanut products to 36.9 µg kg(-1) in Brazil nuts. Most of the studies conducted elsewhere in Brazil found similar results. Total AF intake for the total Brazilian population and high consumers of food relevant for AF contamination in Brazil (upper bound; samples < LOQ = 0.5 LOQ) were 6.8 and 27.6 ng kg(-1) bw day(-1), respectively. Cancer risk reached 0.0753 cancers year(-1) per 10(5) individuals for the total population and 0.3056 cancers year(-1) per 10(5) individuals for high consumers. MOE reached 25 and 6 for the total population and high consumers, respectively, indicating a potential risk for consumers. Aflatoxins are genotoxic carcinogens, and government action should be maintained and continuously improved in order to guarantee that human exposure levels are kept as low as possible.

Isolation, characterization and biological activity of acidic phospholipase A2 isoforms from Bothrops jararacussu snake venom.

Acidic phospholipase A(2) (PLA(2)) isoforms in snake venoms, particularly those from Bothrops jararacussu, have not been characterized. This article reports the isolation and partial biochemical, functional and structural characterization of four acidic PLA(2)s (designated SIIISPIIA, SIIISPIIB, SIIISPIIIA and SIIISPIIIB) from this venom. The single chain purified proteins contained 122 amino acid residues and seven disulfide bonds with approximate molecular masses of 15 kDa and isoelectric points of 5.3. The respective N-terminal sequences were: SIIISPIIA-SLWQFGKMIDYVMGEEGAKS; SIIISPIIB-SLWQFGKMIFYTGKNEPVLS; SIIISPIIIA-SLWQFGKMILYVMGGEGVKQ and SIIISPIIIB-SLWQFGKMIFYEMTGEGVL. Crystals of the acidic protein SIIISPIIB diffracted beyond 1.8 A resolution. These crystals are monoclinic with unit cell dimensions of a = 40.1 A, b = 54.2 A and c = 90.7 A. The crystal structure has been refined to a crystallographic residual of 16.1% (R(free) = 22.9%). Specific catalytic activity (U/mg) of the isolated acidic PLA(2)s were SIIISPIIA = 290.3 U/mg; SIIISPIIB = 279.0 U/mg; SIIISPIIIA = 270.7 U/mg and SIIISPIIIB = 96.5 U/mg. Although their myotoxic activity was low, SIIISPIIA, SIIISPIIB and SIIISPIIIA showed significant anticoagulant activity. However, there was no indirect hemolytic activity. SIIISPIIIB revealed no anticoagulant, but presented indirect hemolytic activity. With the exception of SIIISPIIB, which inhibited platelet aggregation, all the others were capable of inducing time-independent edema. Chemical modification with 4-bromophenacyl bromide did not inhibit the induction of edema, but did suppress other activities.