In vitro palmitoylation of native bovine brain Goα

The native Goα was purified from bovine brain cortex and palmitoylated in vitro. The in vitro palmitoylation site was the same as that in vivo. The internal palmitoylation of purified native Goα was found to be largely maintained. The apparant palmitoylation ratio was significantly increased after the Goa was treated with DTT. The GTPg S binding characteristic of Goα was not influenced by palmitoylation, however, the affinity for LUVs was increased dramatically. The in vitro palmitoylation model of Goα provides a better basis for studying the functional role of G protein palmitoylation in signal transduction.     

Phylogenetic relationships among six species of Epistylis inferred from 18S-ITS1 sequences

Phylogenetic relationships among six species of Epistylis (i. e. E. plicatilis, E. urceolata, E. chrysemydis, E. hentscheli, E. wenrichi, and E. galea) were investigated using sequences of the first internal transcribed spacer region (ITS-1) of ribosomal DNA (rDNA). Amplified rDNA fragment sequences consisted of 215 or 217 bases of the flanking 18S and 5.8S regions, and the entire ITS-1 region (from 145 to 155 bases). There were more than 33 variable bases between E. galea and the other five species in both the 18S region and the ITS-1 region. The affiliation of them was assessed using Neighbor-joining (NJ), maximum parsimony (MP) and maximum likelihood (ML) analyses. In all the NJ, MP and ML analyses E. galea, whose macronucleic position and shape are distinctly different from those of the other five species, was probably diverged from the ancestor of Epistylis earlier than the other five species. The topology in which E. plicatilis and E. hentscheli formed a strongly supported sister clade to E. urceolata, E. chrysemydis, and E. wenrichi was consistent with variations in the thickness of the peristomial lip. We concluded that the macronucleus and peristomial lip might be the important phylogenetic characteristics within the genus Epistylis.     

Evolution of jumping capacity in Tropidurinae lizards: does habitat complexity influence obstacle‐crossing ability?

Jumping performance is relevant for lizards in many ecological contexts and might be favoured during the colonization of structurally complex habitats. Although ground-dwelling lizards use jumps to overcome small obstacles in their natural environments, jumping capacity has been mostly studied in arboreal species. Here, we analysed the evolution of jumping behaviour and performance in lizards from eight ground-dwelling species of Tropidurinae attempting to cross obstacles of different heights in a jumping track, both when undisturbed and under continuous stimulation. To establish ecological correlates with habitat complexity, individuals from two contrasting Brazilian habitats, the arid Caatingas (sand species) and the savannah-like Cerrados (rock species), were compared. Rock species jumped more often and crossed higher obstacles than sand ones in both tests, and performed more vertical than horizontal jumps. Although sand species performed less jumps, they were more successful at crossing the obstacles presented in comparison with rock species. Phylogenetic analyses confirmed these findings and demonstrated a large divergence in jumping capacity between sister-species from different habitats. Therefore, the differences in propensity and endurance for jumping activity appear to be independent of phylogenetic relationships in Tropidurinae and likely reflect an adaptation to the contrasting environments inhabited. The ecological implications of these findings are discussed.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 393–402.     

Sphingosine 1-phosphate activation of ERM contributes to vascular calcification

Vascular calcification is the deposition of mineral in the artery wall by vascular smooth muscle cells (VSMCs) in response to pathological stimuli. The process is similar to bone formation and is an independent risk factor for cardiovascular disease. Given that ceramide and sphingosine 1-phosphate (S1P) are involved in cardiovascular pathophysiology and biomineralization, their role in VSMC matrix mineralization was investigated. During phosphate-induced VSMC mineralization, endogenous S1P levels increased accompanied by increased sphingosine kinase (SK) activity and increased mRNA expression of SK1 and SK2. Consistent with this, mineralization was increased by exogenous S1P, but decreased by C2-ceramide. Mechanistically, exogenous S1P stimulated ezrin-radixin-moesin (ERM) phosphorylation in VSMCs and ERM phosphorylation was increased concomitantly with endogenous S1P during mineralization. Moreover, inhibition of acid sphingomyelinase and ceramidase with desipramine prevented increased S1P levels, ERM activation, and mineralization. Finally, pharmacological inhibition of ERM phosphorylation with NSC663894 decreased mineralization induced by phosphate and exogenous S1P. Although further studies will be needed to verify these findings in vivo, this study defines a novel role for the SK-S1P-ERM pathways in phosphate-induced VSMC matrix mineralization and shows that blocking these pathways with pharmacological inhibitors reduces mineralization. These results may inform new therapeutic approaches to inhibit or delay vascular calcification.     

烟草赤星病菌拮抗性大豆根瘤内生菌的筛选及抑制作用

以烟草赤星病菌为供试病原菌,采用对峙法、代谢液培养法对分离自大豆根瘤的内生细菌进行抑菌筛选,对筛选菌株作用的病原菌菌丝进行显微观察,研究筛选菌株细胞培养特征及生理生化特性、16S rDNA测序序列、系统发育,以及进行温室接种防病试验.结果表明: 大豆根瘤内生菌经初筛、复筛,对烟草赤星病菌抑菌率42%以上的有7株菌,分别属于芽孢杆菌属、假单胞菌属、中华根瘤菌属和寡养单胞菌属.显微观察表明,在拮抗性内生菌作用下病原菌菌丝末端出现明显畸形,呈珊瑚状分枝、球状膨大等;代谢液试验表明,内生菌对病原菌的抑制作用主要是内生菌代谢产生的胞外物质在发挥作用;对峙试验表明,芽孢杆菌可迅速形成生物薄膜,有效阻碍病原菌丝生长和延伸.盆栽防病试验表明,拮抗性内生菌处理下烟草病情指数显著低于对照,表明筛选菌株可作为烟草赤星病的生防菌株资源.