Distribution of macrolides, sulfonamides, and trimethoprim in tropical waters: ubiquitous occurrence of veterinary antibiotics in the Mekong Delta

We investigated the distributions of 12 antibiotics (viz., sulfonamides, macrolides, and trimethoprim) in the water from the Mekong Delta, Vietnam, and compared them with those in the Tamagawa River, Japan. In Vietnam, only a few antibiotics (viz., sulfamethoxazole, sulfamethazine, trimethoprim, and erythromycin-H2O) were detected in the river and canals from urban and rural sites, at concentrations of 7-360 ng/L. This contrasts with the results from the Japanese urban river, where more antibiotics (sulfamethoxazole, sulfapyridine, trimethoprim, erythromycin-H20, azithromycin, clarithromycin, and roxithromycin) were detected at concentrations ranging from 4to 448 ng/L. The concentrations of sulfonamides in the Mekong Delta were comparable to those in the Tamagawa River, whereas macrolide concentrations were lowerthanthose in the Tamagawa River. The ubiquitous occurrence of sulfamethazine, used as a veterinary medicine, in the waters in Vietnam at relatively high concentrations (15-328 ng/L) was unique. Extremely high concentrations of sulfamethazine [(18.5-19.2) x 10(3) ng/L] were detected in pig farm wastewaters, and relatively high concentrations were observed in canals near chicken and pig farms. All these data suggested the potential utility of sulfamethazine as a molecular marker of livestock-source contamination. The present study demonstrated widespread inputs of veterinary medicines to waters in Vietnam.     

Excess heat evolution from nanocomposite samples under exposure to hydrogen isotope gases

Anomalous heat effect by interaction of hydrogen isotope gas and metal nanocomposites supported by zirconia or by silica has been examined. Observed absorption and heat evolution at RT were not too large to be explained by some chemical processes. At elevated temperatures of 200–300 °C, most samples with binary metal nanocomposites produced excess power of 3–24 W lasting for up to several weeks. The excess power was observed not only in the D-Pd·Ni system but also in the HPd·Ni system and HCu·Ni system, while single-element nanoparticle samples produced no excess power. The Pd/Ni ratio is one of the keys to increase the excess power. The maximum phase-averaged excess heat energy exceeded 270 keV/D, and the integrated excess heat energy reached 100 MJ/mol-M or 90 MJ/mol-H. It is impossible to attribute the excess heat energy to any chemical reaction; it is possibly due to radiation-free nuclear process.     

Bacterially Secretable Single-Chain Tandem Macrocyclic Peptides for High Affinity and Inhibitory Activity

The inhibition of protein-protein interactions (PPIs) is an effective approach for therapy. Owing to their large binding surface areas to target proteins, macrocyclic peptides are suitable molecules for PPI inhibition. In this study, we developed single-chain tandem macrocyclic peptides (STaMPtides) that inhibits the vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2). They were artificially designed to comprise two different VEGFR2-binding macrocyclic peptides linked in tandem by peptide linkers and secreted by Corynebacterium glutamicum. Most potent VEGFR2-inhibitory STaMPtides with length-optimized linkers exhibited >1000 times stronger inhibitory activity than their parental monomeric peptides, possibly due to the avidity effect of heterodimerization. Our approach of using STaMPtides for PPI inhibition may be used to inhibit other extracellular factors, such as growth factors and cytokines.