ABSTRACT
The observation that primitive arc magmas are more oxidized than mid-ocean-ridge basalts has led to the paradigm that slab-derived fluids carry SO2 and CO2 that metasomatize and oxidize the sub-arc mantle wedge. We combine petrography and thermodynamic modelling to quantify the oxygen fugacity (fO2) and speciation of the fluids generated by serpentinite dehydration during subduction. Silicate-magnetite assemblages maintain fO2 conditions similar to the quartz-fayalite-magnetite (QFM) buffer at fore-arc conditions. Sulphides are stable under such conditions and aqueous fluids contain minor S. At sub-arc depth, dehydration occurs under more reducing conditions producing aqueous fluids carrying H2S. This finding brings into question current models in which serpentinite-derived fluids are the cause of oxidized arc magmatism and has major implications for the global volatile cycle, as well as for redox processes controlling subduction zone geodynamics.
ABSTRACT
In the face of a possible loss of genetic diversity in plants due the environmental changes, actions to ensure the genetic variability are an urgent necessity. The extraction of Brazilian pepper fruits is a cause of concern because it results in the lack of seeds in soil, hindering its distribution in space and time. It is important to address this concern and explore the species, used by riparian communities and agro-factories without considering the need for keeping the seeds for natural seed banks and for species sustainability. The objective of this study was to evaluate the structure and the genetic diversity in natural Brazilian pepper populations (Schinus terebinthifolius Raddi). Twenty-two alleles in 223 individuals were identified from eight forest remnants located in the states of Minas Gerais, Espírito Santo, and Sergipe. All populations presented loci in Hardy-Weinberg equilibrium deviation. Four populations presented six combinations of loci in linkage disequilibrium. Six exclusive alleles were detected in four populations. Analysis of molecular variance showed the absence of diversity between regions and that between the populations (GST) was 41%. Genetic diversity was structured in seven clusters (ΔK7). Brazilian pepper populations were not structured in a pattern of isolation by distance and present genetic bottleneck. The populations São Mateus, Canastra, Barbacena, and Ilha das Flores were identified as management units and may support conservation projects, ecological restoration and in implementation of management plans for Brazilian pepper in the State of Sergipe.
Subject(s)
Anacardiaceae/genetics , Genetic Variation , Brazil , DNA, Plant , Genetic Markers , Genotype , Microsatellite RepeatsABSTRACT
Hepatitis E is a form of endemic acute hepatitis found in humans in many countries worldwide and is caused by the hepatitis E Virus (HEV). Detection of HEV in pigs indicates that they may be carriers, possibly through zoonosis. The prevalence of HEV in pigs in Colombia is unknown. Studies in the US found that 11% of pig livers sold in grocery stores are contaminated with HEV. It is also known that HEV can be inactivated when cooked, as it is labile to high temperatures. The aim of this study was to determine HEV contamination in pig livers sold in Medellín, Antioquia. A total of 150 livers from 5 slaughterhouses and 100 livers in grocery stores from different social strata of the city of Medellin analyzed to detect a segment of the HEV open reading frame-1 using reverse transcription-polymerase chain reaction. The results showed that 41.3% of pig livers from slaughterhouses and 25% of livers from grocery stores tested positive for HEV. Thus, the HEV genome is present in pig livers sold in Antioquia, revealing the presence of this virus in pigs from Colombia and the need subject entrails to proper cooking processes before consumption. Further research is required to determine the role of this virus in public health and pork production in Colombia.
