小反刍兽疫病毒研究进展

小反刍兽疫（PPR）是由小反刍兽疫病毒（PPRV）引起的一种主要感染小反刍动物的急性、烈性、接触性A类传染病,患病率、死亡率高。本文就世界PPR流行状况、PPRV基因组及病毒结构蛋白、PPRV检测方法、最新的药物及疫苗、存在的问题等方面做了简要综述。     

中国小反刍兽疫疫情分析

为分析中国PPRV毒株分子演变特点和疫情传播路线,从NCBI下载中国和世界其他国家全部PPRV毒株N和F基因全序列,应用分子生物学软件,并结合疫情发生的地理位置进行系统分析。结果显示,中国西藏阿里地区PPRV毒株之间核苷酸同源性为100%,其与西藏那曲地区毒株核苷酸同源性为99.9%;中国毒株与其他国家毒株F基因核苷酸序列分析显示,同源性为89.7%～98.8%,同源性最低的为科特迪瓦1989年毒株,同源性最高的为孟加拉国2010年毒株;N 基因核苷酸序列分析显示,同源性为69.5%～98.5%,同源性最低的为朝鲜2002年毒株,同源性最高的为印度1995年毒株;F和N 基因系统进化关系分析均显示,中国西藏3株PPRV均属于基因Ⅳ系;截止2014年3月30日,中国由西至东9省份发生该疫情。更加全面的分析结果,有待于更多PPRV流行毒株N或F基因全序列在GenBank的公布。     

Evaluation of efficacy of stabilizers on the thermostability of live attenuated thermo-adapted <Emphasis Type="Italic">Peste des petits ruminants</Emphasis> vaccines

In this study, thermo-adapted (Ta) PPR vaccines were assessed for their stability at 25, 37, 40, 42 and 45°C in lyophilized form using two extrinsic stabilizers {lactalbumin hydrolysate-sucrose (LS) and stabilizer E} and in reconstituted form with the diluents (1 mol/L MgSO₄ or 0.85% NaCl). The lyophilized vaccines showed an expiry period of 24–26 days at 25°C, 7–8 days at 37°C and 3–4 days at 40°C. LS stabilizer was superior at 42°C with a shelf-life of 44 h, whereas in stabilizer E, a 40 h shelf-life with a comparable half-life was observed. At 45°C, the half-life in stabilizer E was better than LS and lasted for 1 day. Furthermore, the reconstituted vaccine maintained the titre for 48 h both at 4°C and 25°C and for 24–30 h at 37°C. As both the stabilizers performed equally well with regard to shelf-life and half-life, the present study suggests LS as stabilizer as a choice for lyophilization with 0.85% NaCl diluent, because it has better performance at higher temperature. These Ta vaccines can be used as alternatives to existing vaccines for the control of the disease in tropical countries as they are effective in avoiding vaccination failure due to the breakdown in cold-chain maintenance, as this vaccine is considerably more stable at ambient temperatures.     

Reverse Genetics for Peste des Petits Ruminants Virus: Current Status and Lessons to Learn from Other Non-segmented Negative-Sense RNA Viruses

Peste des petits ruminants (PPR) is a highly contagious transboundary animal disease with a severe socio-economic impact on the livestock industry, particularly in poor countries where it is endemic. Full understanding of PPR virus (PPRV) pathobiology and molecular biology is critical for effective control and eradication of the disease. To achieve these goals, establishment of stable reverse genetics systems for PPRV would play a key role. Unfortunately, this powerful technology remains less accessible and poorly documented for PPRV. In this review, we discussed the current status of PPRV reverse genetics as well as the recent innovations and advances in the reverse genetics of other non-segmented negative-sense RNA viruses that could be applicable to PPRV. These strategies may contribute to the improvement of existing techniques and/or the development of new reverse genetics systems for PPRV.     

PPR蛋白调控植物细胞器RNA加工的分子功能

35肽重复（pentatricopeptide repeat, PPR）蛋白是2000年发现的一类由多个重复单位串联而成的核编码蛋白质。PPR蛋白广泛存在于真核生物中,在陆生植物中尤为普遍。PPR蛋白大多定位于线粒体或叶绿体。多项研究表明,PPR蛋 白为序列特异性RNA结合蛋白质,在细胞器RNA编辑、剪接、稳定、切割及翻译等转录后加工过程发挥重要作用。PPR蛋白功能缺陷导致植物生长发育异常,甚至胚胎致死。本文主要就PPR蛋白功能及作用机制进行综述,并对尚待解决的问题及研究前景加以探讨,以期为PPR蛋白的深入研究提供思路。     

DYW-type PPR proteins in a heterolobosean protist: plant RNA editing factors involved in an ancient horizontal gene transfer?

A particular type of pentatricopeptide repeat (PPR) proteins with variable length of the 35 aa PPR motifs and conserved carboxyterminal extensions, named the PLS proteins, was so far exclusively identified in land plants. Several PLS proteins with such domain extensions (E, E+, DYW) were shown to be involved in plant organellar RNA editing but their evolutionary origin had remained enigmatic. We here report the first case of DYW-type PLS proteins outside of the plant kingdom in the protist Naegleria gruberi and hypothesize on horizontal gene transfer in very early land plant evolution.