Spatial dynamics of Chinese Muntjac related to past and future climate fluctuations

Climate fluctuations in the past and in the future are likely to result in population expansions,shifts,or the contraction of the ecological niche of many speci...     

Preparation, characterization and properties of superabsorbent nanocomposites based on natural guar gum and modified rectorite

Novel guar gum-g-poly(sodium acrylate)/rectorite (GG-g-PNaA/REC) superabsorbent nanocomposites were prepared in aqueous solution using guar gum (GG), partially neutralized acrylic acid (NaA), acidified rectorite (H⁺-REC) and organified rectorite (CTA⁺-REC) by cetyltrimethylammonium bromide (CTAB) as raw materials, ammonium persulfate (APS) as initiator and N,N′-methylenebisacrylamide (MBA) as crosslinker. FTIR spectra confirmed that NaA had been grafted onto GG chains and the OH groups of REC participated in polymerization reaction. Exfoliated nanocomposite was obtained for H⁺-REC and intercalated structure was formed for CTA⁺-REC as shown by XRD results. SEM observations show REC has been uniformly dispersed in polymeric matrix. Effects of HCl concentration, organification degree of CTA⁺-REC and content of REC on swelling capabilities were investigated and the swelling kinetics of nanocomposites was evaluated. Results indicate that modifying REC by acidification and organification can improve swelling properties of the resultant nanocomposites, and GG-g-PNaA/CTA⁺-REC exhibited higher swelling capability and swelling rate contrast to GG-g-PNaA/H⁺-REC.     

几种猕猴桃种间杂交亲和性的探讨

以中华猕猴桃、毛花猕猴桃、美味猕猴桃及阔叶猕猴桃进行种间杂交,结果表明:各杂交组合的座果率与对照组一样,均为100％;父本花粉萌发率与对照组相近,其杂交当代果实重量、种子数量及种子千粒重也与对照组相近;相同的母本,其当代杂交果实的重量及种子数量与父本花粉萌发率的高低成正比。这不但说明了各杂交组合所采用亲本之间的亲和性,而且为生产上利用不同种生活力强的猕猴桃雄株花粉进行人工辅助授粉提供依据。     

Oestrogen regulates the expression of cathepsin E-A-like gene through ER$$\upbeta $$ in liver of chicken ( Gallus gallus)

The cathepsin E-A-like, also known as ‘similar to nothepsin’, is a new member of the aspartic protease family, which may take part in processing of egg yolk macromolecules, due to it was identified in the chicken egg-yolk. Previously, studies have suggested that the expression of cathepsin E-A-like increased gradually during sexual maturation of pullets, but the exact regulation mechanism is poorly understood. In this study, to gain insight into the function and regulation mechanism of the gene in egg-laying hen, we cloned the cathepsin E-A-like gene and evaluated its evolutionary origin by using both phylogenetic and syntenic methods. The mode of the gene expression regulation was analysed through stimulating juvenile hens with \(17\upbeta \)-estradiol and chicken embryo hepatocytes with \(17\upbeta \)-estradiol combined with oestrogen receptor antagonists including MPP, ICI 182,780 and tamoxifen. Our results showed that cathepsin E-A-like was an orthologoues gene with nothepsin, which is present in birds but not in mammals. The expression of cathepsin E-A-like significantly increased in a dose-dependent manner after the juvenile hens were treated with \(17\upbeta \)-estradiol (\(P~<~0.05\)). Compared with the \(17\upbeta \)-estradiol treatment group, the expression of cathepsin E-A-like was not significantly changed when the hepatocytes were treated with \(17\upbeta \)-estradiol combined with MPP (\(P~<~0.05\)). In contrast, compared with the \(17\upbeta \)-estradiol combined with MPP treatment group, the expression of cathepsin E-A-like was significantly downregulated when the hepatocytes were treated with \(17\upbeta \)-estradiol combined with tamoxifen or ICI 182,780 (\(P~<~0.05\)). These results demonstrated that cathepsin E-A-like shared the same evolutionary origin with nothepsin. The expression of cathepsin E-A-like was regulated by oestrogen, and the regulative effect was predominantly mediated through ER-\(\upbeta \) in liver of chicken.