Selenium and mercury levels in rat liver slices co-treated with diphenyl diselenide and methylmercury

Organoseleno-compounds have been investigated for its beneficial effects against methylmercury toxicity. In this way, diphenyl diselenide (PhSe)₂ was demonstrated to decrease Hg accumulation in mice, protect against MeHg-induced mitochondrial dysfunction, and protect against the overall toxicity of this metal. In the present study we aimed to investigate if co-treatment with (PhSe)₂ and MeHg could decrease accumulation of Hg in liver slices of rats. Rat liver slices were co-treated with (PhSe)₂ (0.5; 5 µM) and/or MeHg (25 µM) for 30 min at 37 °C and Se and Hg levels were measured by inductively coupled plasma mass spectrometry (ICP-MS) in the slices homogenate, P1 fraction, mitochondria and incubation medium. Co-treatment with (PhSe)₂ and MeHg did not significantly alter Se levels in any of the samples when compared with compounds alone. In addition, co-treatment with (PhSe)₂ and MeHg did not decrease Hg levels in any of the samples tested, although, co-incubation significantly increased Hg levels in homogenate. We suggest here that (PhSe)₂ could exert its previously demonstrated protective effects not by reducing MeHg levels, but forming a complex with MeHg avoiding it to bind to critical molecules in cell.     

The largemouth bass Micropterus salmoides (Lacepède, 1802): impacts of a powerful freshwater fish predator outside of its native range

Reviews in Fish Biology and Fisheries - Biological invasions via anthropogenic vectors, intentional or not, are one of the main causes of ecological change in aquatic ecosystems. Micropterus...     

Insight into the sulfur metabolism of Desulfurella amilsii by differential proteomics

Many questions regarding proteins involved in microbial sulfur metabolism remain unsolved. For sulfur respiration at low pH, the terminal electron acceptor is still unclear. Desulfurella amilsii is a sulfur-reducing bacterium that respires elemental sulfur (S⁰) or thiosulfate, and grows by S⁰ disproportionation. Due to its versatility, comparative studies on D. amilsii may shed light on microbial sulfur metabolism. Requirement of physical contact between cells and S⁰ was analyzed. Sulfide production decreased by around 50% when S⁰ was trapped in dialysis membranes, suggesting that contact between cells and S⁰ is beneficial, but not strictly needed. Proteome analysis was performed under the aforementioned conditions. A Mo-oxidoreductase suggested from genome analysis to act as sulfur reductase was not detected in any growth condition. Thiosulfate and sulfite reductases showed increased abundance in thiosulfate-reducing cultures, while rhodanese-like sulfurtransferases were highly abundant in all conditions. DsrE and DsrL were abundantly detected during thiosulfate reduction, suggesting a modified mechanism of sulfite reduction. Proteogenomics suggest a different disproportionation pathway from what has been reported. This work points to an important role of rhodaneses in sulfur processes and these proteins should be considered in searches for sulfur metabolism in broader fields like meta-omics.     

The use of a tannin crude extract from Cistus ladanifer L. to protect soya-bean protein from degradation in the rumen

Cistus ladanifer L. (CL) is a perennial shrub abundant in dry woods and dry land of Mediterranean zone, with high level of tannins. Tannins bind to protein, preventing its degradation in the digestive compartments. This tannin/protein complex may be advantageous when partially protecting good-quality feed protein from excessive rumen protein degradation. The objective of this trial was to use a CL phenol crude extract to prevent excessive rumen degradation of soya-bean meal protein. The phenolic compounds were extracted using an acetone/water solution (70:30, v/v). Soya-bean meal was then treated with this crude CL extract, containing 640 g of total phenols (TP) per kg of dry matter (DM), in order to obtain mixtures with 0, 12.5, 25, 50, 100 and 150 g of TP per kg DM. Three rumen-cannulated rams were used to assess in sacco rumen degradability of DM and nitrogen (N). The three-step in vitro procedure was used to determine intestinal digestibility. Increasing extract concentrations quadratically decreased the N-soluble fraction a (R² = 0.96, P = 0.0001) and increased the non-soluble degradable fraction b (R² = 0.92, P = 0.005). The rate of degradation c linearly decreased with CL extract doses (R² = 0.44, P = 0.0065). For the effective rumen degradability of N, a linear reduction (R² = 0.94, P < 0.0001) was observed. The in vitro intestinal digestibility of protein (ivID) quadratically decreased (R² = 0.99, P < 0.0001) with TP inclusion and the rumen undegradable protein (RUP) showed a quadratic increase (R² = 0.94, P = 0.0417). Total intestinal protein availability, computed from the RUP and ivID, linearly decreased with TP inclusion level (R² = 0.45, P = 0.0033).     

Comprehensive proteomic analysis of human cervical-vaginal fluid

Cervical-vaginal fluid (CVF) is a potential rich source of biomarkers for enhancing our understanding of human parturition and pathologic conditions affecting pregnancy. In this study, we performed a comprehensive survey of the CVF proteome in pregnancy utilizing multidimensional liquid chromatography (2D-LC) coupled with mass spectrometry and gel-electrophoresis-based protein separation and identification. In total, 150 unique proteins were identified using multiple protein identification algorithms. Metabolism (32%) and immune response-related (22%) proteins are the major functional categories represented in the CVF proteome. A comparison of the CVF, serum, and amniotic fluid proteomes showed that 77 proteins are unique to CVF, while 56 and 17 CVF proteins also occur in serum and amniotic fluid, respectively. This data set provides a foundation for evaluation of these proteins as potential CVF biomarkers for noninvasive diagnosis of pregnancy-related disorders.     

Epiphytic cyanobacterial strains in the roots of Salvinia auriculata and the effect of light and nutrients on the production of heterocyst,akinete and hormogonia

Aquatic Ecology - In epiphytic associations, cyanobacteria form the periphyton with phytoplanktonic algae and with aquatic macrophytes. In this study, we found homocytous and heterocytous...