基因产物功能分类系统

介绍了4个目前常见的基因产物功能分类体系,第一代功能分类体系GenProtEC、MIPS和KEGG大都是在MonicaRiley提出的分类系统的基础上形成的。而正在发展的GeneOntology(GO)是第二代功能分类体系,它涵盖了更多生物体基因产物的功能。该文通过对这几个分类系统的比较,阐明各自的特点,说明其存在的问题。     

Inferring deleterious-mutation parameters in natural daphnia populations

Deng and Lynch (1, 2) proposed to characterize deleterious genomic mutations from changes in the mean and genetic variance of fitness traits upon selfing in outcrossing populations. Such observations can be readily acquired in cyclical parthenogens. Selfing and life-table experiments were performed for two such Daphnia populations. A significant inbreeding depression and an increase of genetic variance for all traits analyzed were observed. Deng and Lynch’s (2) procedures were employed to estimate the genomic mutation rate (U), mean dominance coefficient $\left( {\bar h} \right)$ , mean selection coefficient $\left( {\bar s} \right)$ , and scaled genomic mutational variance (V m/Ve). On average, Û, $\left( {\hat \bar h} \right)$ , $\left( {\hat \bar s} \right)$ and $\frac{{\hat V_m }}{{V_e }}$ (^ indicates an estimate) are 0.84, 0.30, 0.14 and 4.6E-4 respectively. For the true values, the Û and $\hat \bar h$ are lower bounds, and $\hat \bar s$ and $\frac{{\hat V_m }}{{V_e }}$ upper bounds.     

Potential enzyme toxicity of perfluorooctanoic acid

Using equilibrium dialysis, isothermal titration calorimetry (ITC) and circular dichroism (CD), the interactions of perfluorooctanoic acid (PFOA) and lysozyme were investigated under normal human physiological conditions, i.e., at pH 4.40, 6.00 and 7.40 at 37°C in 0.15 M electrolyte. A simple and rapid spectrophotometric method was developed for determining PFOA concentrations. Interactions between PFOA and lysozyme were found to result from non-specific non-covalent bonds—F/N and F/O affinity, ion-pair attraction, hydrogen bond, hydrophobic interaction and van der Waals force—and were affected by chemical adsorption to monolayers. The results indicated that binding of PFOA altered the secondary structure and activity of lysozyme. This work provides a useful experimental strategy for research into the enzyme toxicity of organic chemicals, e.g., food additives and organic contaminants, and it may help to elucidate the molecular toxicology of human health risks.     

Modeling and mechanism of the adsorption of proton onto natural bamboo sawdust

Natural bamboo sawdust with cellulose-lignin polymeric structure was used as a raw adsorbent to remove heavy metal and dyes in water. The analysis of surface properties showed that high proton affinity sites were mainly composed of phenolic and alcohol hydroxyl, while low proton affinity sites mainly consisted of carboxylic acid, silicon hydroxyl, aluminum hydroxyl and some low densities of sulfhydryl and phosphoryl groups. The results fitted by NEM surface complexation model showed: three-sites model fitted acid-base titration data better than two-sites and one-site model. Acid-base titration experiments showed the amount of acid and base consumed was not uniform between acid and alkali side. This was probably due to the swelling of cellulose in acid side, but the possibility that different reactions occurred in acid and alkali side cannot be completely excluded. Pznpc of sawdust was between pH 5.2 and 5.5.