Role of the Nuclease Activities Encoded by Herpes Simplex Virus 1 UL12 in Viral Replication and Neurovirulence

Enzyme-dead mutations in the herpes simplex virus 1 UL12 gene that abolished its endo- and exonuclease activities only slightly reduced viral replication in cell cultures. However, the UL12 null mutation significantly reduced viral replication, suggesting that a UL12 function(s) unrelated to its nuclease activities played a major role in viral replication. In contrast, the enzyme-dead mutations significantly reduced viral neurovirulence in mice, suggesting that UL12 nuclease activities were critical for viral pathogenesis in vivo.     

温度对金边土鳖实验种群影响的研究

金边土鳖(Opisthoplatia orientalis)属蜚蠊目,姬蠊科(Phyllodromiidae)光蠊亚科(Epilamprinae)。又名东方后片蠊。产于华南、台湾一带。金边土鳖为渐变态昆虫,一生经卵、若虫、成虫三阶段,但因卵胎生之故,所以卵在母体内直接孵化为若虫后产出体外。民间常用土鳖虫的成虫制药来治疗散瘀、跌打损伤、妇女经闭等症,近年来更有对癌症有一定疗效之说,所以是重要的药用昆虫之一。其中华南之特产金边土鳖更享有出口的盛誉。     

The secondary coordination sphere and axial ligand effects on oxygen reduction reaction by iron porphyrins: a DFT computational study

Oxygen reduction reaction (ORR) catalyzed by a bio-inspired iron porphyrin bearing a hanging carboxylic acid group over the porphyrin ring, and a tethered axial imidazole ligand was studied by DFT calculations. BP86 free energy calculations of the redox potentials and pK _a’s of reaction components involved in the proton coupled electron transfer (PCET) reactions of the ferric-hydroxo and -superoxo complexes were performed based on Born–Haber thermodynamic cycle in conjunction with a continuum solvation model. The comparison was made with iron porphyrins that lack either in the hanging acid group or axial ligand, suggesting that H-bond interaction between the carboxylic acid and iron-bound hydroxo, aquo, superoxo, and peroxo ligands (de)stabilizes the Fe–O bonding, resulting in the increase in the reduction potential of the ferric complexes. The axial ligand interaction with the imidazole raises the affinity of the iron-bound superoxo and peroxo ligands for proton. In addition, a low-spin end-on ferric-hydroperoxo intermediate, a key precursor for O–O cleavage, can be stabilized in the presence of axial ligation. Thus, selective and efficient ORR of iron porphyrin can be achieved with the aid of the secondary coordination sphere and axial ligand interactions.     

融合基因umcel5N-CBM的构建、表达及融合酶性质分析

BM,并实现了融合基因在大肠杆菌BL21(DE3)pLysS中的表达.研究结果表明,融合酶Umcel5N-CBM与结晶纤维素(avicel)以及滤纸粉末的结合能力比原始酶Umcel5N提高了约一倍,但未显示出降解结晶纤维素的新活性,说明在结晶纤维素的降解过程中,纤维素酶的催化功能域起到关键作用.     

Selenite and ebselen supplementation attenuates <Emphasis Type="SmallCaps">d</Emphasis>-galactose-induced oxidative stress and increases expression of SELR and SEP15 in rat lens

Selenite and ebselen supplementation has been shown to possess anti-cataract potential in some experimental animal models of cataract, however, the underlying mechanisms remain unclear. The present study was designed to evaluate the anti-cataract effects and the underlying mechanisms of selenite and ebselen supplementation on galactose induced cataract in rats, a common animal model of sugar cataract. Transmission electron microscopy images of lens fiber cells (LFC) and lens epithelial cells (LEC) were observed in d-galactose-induced experimental cataractous rats treated with or without selenite and ebselen, also redox homeostasis and expression of proteins such as selenoprotein R (SELR), 15kD selenoprotein (SEP15), superoxide dismutase 1 (SOD1), catalase (CAT), β-crystallin protein, aldose reductase (AR) and glucose-regulated protein 78 (GRP78) were estimated in the lenses. The results showed that d-galactose injection injured rat lens and resulted in cataract formation; however, selenite and ebselen supplementation markedly alleviated ultrastructural injury of LFC and LEC. Moreover, selenite and ebselen supplementation could mitigate the oxidative damage in rat lens and increase the protein expressions of SELR, SEP15, SOD1, CAT and β-crystallin, as well as decrease the protein expressions of AR and GRP78. Taken together, these findings for the first time reveal the anti-cataract potential of selenite and ebselen in galactosemic cataract, and provide important new insights into the anti-cataract mechanisms of selenite and ebselen in sugar cataract.