Consensus Mutagenesis and Ancestral Reconstruction Provide Insight into the Substrate Specificity and Evolution of the Front-End Δ6-Desaturase Family.

Marine algae are a major source of ω-3 long-chain polyunsaturated fatty acids (ω3-LCPUFAs), which are conditionally essential nutrients in humans and a target for industrial production. The biosynthesis of these molecules in marine algae requires the desaturation of fatty acids by Δ6-desaturases, and enzymes from different species display a range of specificities toward ω3- and ω6-LCPUFA precursors. In the absence of a molecular structure, the structural basis for the variable substrate specificity of Δ6-desaturases is poorly understood.

A forward genetic screen identifies a negative regulator of rapid Ca-dependent cell egress (MS1) in the intracellular parasite .

, like all apicomplexan parasites, uses Ca signaling pathways to activate gliding motility to power tissue dissemination and host cell invasion and egress. A group of "plant-like" Ca-dependent protein kinases (CDPKs) transduces cytosolic Ca flux into enzymatic activity, but how they function is poorly understood. To investigate how Ca signaling activates egress through CDPKs, we performed a forward genetic screen to isolate gain-of-function mutants from an egress-deficient knockout strain.

Simultaneous determination of trace Cd(II), Pb(II) and Cu(II) by differential pulse anodic stripping voltammetry using a reduced graphene oxide-chitosan/poly-l-lysine nanocomposite modified glassy carbon electrode.

The reduced graphene oxide (RGO) and Chitosan (CS) hybrid matrix RGO-CS were coated onto the glassy carbon electrode (GCE) surface, then, poly-l-lysine films (PLL) were prepared by electropolymerization with cyclic voltammetry (CV) method to prepare RGO-CS/PLL modified glassy carbon electrode (RGO-CS/PLL/GCE) for the simultaneous electrochemical determination of heavy metal ions Cd(II), Pb(II) and Cu(II). Combining the advantageous features of RGO and CS, RGO and CS are used together because the positively charged CS can interact with the negatively changed RGO to prevent their aggregation. Furthermore, CS has many amino groups along its macromolecular chains and possessed strongly reactive with metal ions.

Classification and substrate head-group specificity of membrane fatty acid desaturases.

Membrane fatty acid desaturases are a diverse superfamily of enzymes that catalyze the introduction of double bonds into fatty acids. They are essential in a range of metabolic processes, such as the production of omega-3 fatty acids. However, our structure-function understanding of this superfamily is still developing and their range of activities and substrate specificities are broad, and often overlapping, which has made their systematic characterization challenging.

The intracellular HBV DNAs as novel and sensitive biomarkers for the clinical diagnosis of occult HBV infection in HBeAg negative hepatocellular carcinoma in China.

This study aimed to investigate the virological status in liver (both tumor and adjacent non-tumor tissue), the clinical features and the contribution of occult HBV infection (OBI) to postoperative prognosis in HBeAg-negative(-) hepatocellular carcinoma (HCC) patients in China. Using quantitative TaqMan fluorescent real-time PCR assays, HBV covalently closed circular DNA (cccDNA) and total DNA (tDNA) were both quantified in 11 (HBsAg(-)) and 57 (HBsAg-positive(+)) pairs of tumor tissue (TT) and adjacent non-tumor tissue (ANTT) obtained from HBeAg(-) HCC patients who received no antiviral treatment and were negative for anti-HCV before surgical treatment. Of 11 HBsAg(-) patients, 36% were with HBsAb(+) HBeAb(+) HBcAb(+).