Inhibitory effect of chlorinated guaiacols on methanogenic activity of anaerobic digester sludge

Of four chlorinated guaiacols, tetrachloroguaiacol at 62 M inhibited acetate methanogenesis, the strongest decreasing activity by 50%. 4,5,6-Trichloroguaiacol, 4,5-dichloroguaiacol, and 4-chloroguaiacol showed 50% inhibition at 0.13, 0.32, and 1.50 mM, respectively. Degradation test results of volatile fatty acids (acetic, propionic, and butyric acid) by anaerobic digester sludge (stored 5 weeks) indicated that syntrophic butyrate degraders of this sludge were more sensitive to tetrachloroguaiacol than acetoclastic methanogens and syntrophic propionate degraders.     

Vnd/nkx, ind/gsh, and msh/msx: conserved regulators of dorsoventral neural patterning?

Expression of vnd in ventral, ind in intermediate, and msh in dorsal columns of fly neurectoderm, and of homologous gene families in corresponding domains of vertebrate neurectoderm, suggests that elements of dorsoventral neural patterning have been evolutionarily conserved. However, upstream signaling pathways regulating this columnar gene expression pattern appear to have diverged significantly throughout evolution. In addition, while recent loss-of-function studies in flies and mice indicate that these three genes may have a conserved role in regional specification, there is no obvious conservation of the particular cell fates deriving from corresponding domains. The three-column expression pattern may thus represent a developmental mechanism that is more resistant to evolutionary changes than genetic events upstream or downstream of it.     

Turning the 'mustard oil bomb' into a 'cyanide bomb': aromatic glucosinolate metabolism in a specialist insect herbivore

Plants have evolved a variety of mechanisms for dealing with insect herbivory among which chemical defense through secondary metabolites plays a prominent role. Physiological, behavioural and sensorical adaptations to these chemicals provide herbivores with selective advantages allowing them to diversify within the newly occupied ecological niche. In turn, this may influence the evolution of plant metabolism giving rise to e.g. new chemical defenses. The association of Pierid butterflies and plants of the Brassicales has been cited as an illustrative example of this adaptive process known as 'coevolutionary armsrace'. All plants of the Brassicales are defended by the glucosinolate-myrosinase system to which larvae of cabbage white butterflies and related species are biochemically adapted through a gut nitrile-specifier protein. Here, we provide evidence by metabolite profiling and enzyme assays that metabolism of benzylglucosinolate in Pieris rapae results in release of equimolar amounts of cyanide, a potent inhibitor of cellular respiration. We further demonstrate that P. rapae larvae develop on transgenic Arabidopsis plants with ectopic production of the cyanogenic glucoside dhurrin without ill effects. Metabolite analyses and fumigation experiments indicate that cyanide is detoxified by β-cyanoalanine synthase and rhodanese in the larvae. Based on these results as well as on the facts that benzylglucosinolate was one of the predominant glucosinolates in ancient Brassicales and that ancient Brassicales lack nitrilases involved in alternative pathways, we propose that the ability of Pierid species to safely handle cyanide contributed to the primary host shift from Fabales to Brassicales that occured about 75 million years ago and was followed by Pierid species diversification.     

Long non‐coding RNAs in melanoma

Melanoma is the most lethal cutaneous cancer with a highly aggressive and metastatic phenotype. While recent genetic and epigenetic studies have shed new insights into the mechanism of melanoma development, the involvement of regulatory non‐coding RNAs remain unclear. Long non‐coding RNAs (lncRNAs) are a group of endogenous non‐protein‐coding RNAs with the capacity to regulate gene expression at multiple levels. Recent evidences have shown that lncRNAs can regulate many cellular processes, such as cell proliferation, differentiation, migration and invasion. In the melanoma, deregulation of a number of lncRNAs, such as HOTAIR, MALAT1, BANCR, ANRIL, SPRY‐IT1 and SAMMSON, have been reported. Our review summarizes the functional role of lncRNAs in melanoma and their potential clinical application for diagnosis, prognostication and treatment.     

Protective effect of bixin on carbon tetrachloride-induced hepatotoxicity in rats

Background

The liver is an important organ for its ability to transform xenobiotics, making the liver tissue a prime target for toxic substances. The carotenoid bixin present in annatto is an antioxidant that can protect cells and tissues against the deleterious effects of free radicals. In this study, we evaluated the protective effect of bixin on liver damage induced by carbon tetrachloride (CCl₄) in rats.

Results

The animals were divided into four groups with six rats in each group. CCl₄ (0.125 mL kg^-1 body wt.) was injected intraperitoneally, and bixin (5.0 mg kg^-1 body wt.) was given by gavage 7 days before the CCl₄ injection. Bixin prevented the liver damage caused by CCl₄, as noted by the significant decrease in serum aminotransferases release. Bixin protected the liver against the oxidizing effects of CCl₄ by preventing a decrease in glutathione reductase activity and the levels of reduced glutathione and NADPH. The peroxidation of membrane lipids and histopathological damage of the liver was significantly prevented by bixin treatment.

Conclusion

Therefore, we can conclude that the protective effect of bixin against hepatotoxicity induced by CCl₄ is related to the antioxidant activity of the compound.     

The role of CCoAOMT1 and COMT1 in Arabidopsis anthers

Arabidopsis caffeoyl coenzyme A dependent O-methyltransferase 1 (CCoAOMT1) and caffeic acid O-methyltransferase 1 (COMT1) display a similar substrate profile although with distinct substrate preferences and are considered the key methyltransferases (OMTs) in the biosynthesis of lignin monomers, coniferyl and sinapoylalcohol. Whereas CCoAOMT1 displays a strong preference for caffeoyl coenzyme A, COMT1 preferentially methylates 5-hydroxyferuloyl CoA derivatives and also performs methylation of flavonols with vicinal aromatic dihydroxy groups, such as quercetin. Based on different knockout lines, phenolic profiling, and immunohistochemistry, we present evidence that both enzymes fulfil distinct, yet different tasks in Arabidopsis anthers. CCoAOMT1 besides its role in vascular tissues can be localized to the tapetum of young stamens, contributing to the biosynthesis of spermidine phenylpropanoid conjugates. COMT1, although present in the same organ, is not localized in the tapetum, but in two directly adjacent cells layers, the endothecium and the epidermal layer of stamens. In vivo localization and phenolic profiling of comt1 plants provide evidence that COMT1 neither contributes to the accumulation of spermidine phenylpropanoid conjugates nor to the flavonol glycoside pattern of pollen grains.