绵羊卵泡发育过程中关键信号通路研究进展

卵泡从原始卵泡发育为成熟卵泡，直至排卵、黄体发育等过程都受到精密的调控，产生大量的优势卵泡是绵羊产多羔及实现快速扩繁的关键因素。研究发现，相关信号通路和转录因子通过影响绵羊卵泡中卵母细胞、颗粒细胞的生长，进而调控卵泡的发育成熟，对这些信号通路进行深入了解，有助于探索卵泡发育的调控机制，早日实现绵羊高效繁育。Notch是卵泡发育过程中发挥重要作用的高度保守信号通路，PI3K/AKT/mTOR信号通路各成员都是广泛存在于细胞内的信号转导分子，在卵泡发育早期发挥了主要作用，还有间隙连接（gap junction，GJ）和跨带突触（transzonal projections，TZPs）等物理连接方式，在细胞间的交流通讯起到重要作用。作者详细介绍了Notch信号通路、PI3K/AKT/mTOR信号通路、间隙连接及跨带突触的结构功能在绵羊卵泡发育中的调控作用，为进一步探明绵羊卵泡发育的调控机制提供参考。     

以全产业链思维优化甘肃省“粮改饲”生产力布局

用全产业链思维优化“粮改饲”生产力布局具有重要的现实意义和理论价值。本文以甘肃省为例,总结甘肃省“粮改饲”工作已取得的工作成效和不足,论述了“粮改饲”构建全产业链的必要性,初步探讨了甘肃省“粮改饲”全产业链模式和布局优化,并提出完善相关支持政策、培育壮大龙头企业、高度重视品牌建设和创新科技带动引领4条对策建议。 [关键词]全产业链|粮改饲|生产力布局|甘肃省     

Molecular and serologic characterization, pathogenicity, and protection studies with infectious bronchitis virus field isolates from California

In this study, we characterized three variant infectious bronchitis virus (IBV) strains isolated in 2003 and 2004 from broiler chickens in California and compared them to previously isolated California variant viruses and to common vaccine serotypes used in the United States. We conducted genetic, serologic, and pathogenicity studies on all three isolates, then tested different vaccines against one of the viruses. Genetically the three variant IBV strains, designated CA557/03, CA706/03, and CA1737/04, were not related to each other. GenBank BLAST database search and phylogenetic analysis of the hypervariable region of the S1 subunit of the spike gene to determine the most closely related viruses to the three variants showed the CA557/03 variant to be 81.8% similar to the CAV/CA56b/91 whereas the CA706/03 and CA1737/04 variant viruses were only distantly related to Dutch/D1466/81 (72.2%), a vaccine strain used in Europe, and Korea/K142/02 (72.7%), a Korean field isolate, respectively. Cross virus-neutralization testing showed that none of the 2003-04 California IBV variant viruses were serologically related to each other or to Ark, Conn, or Mass vaccine strains. In addition the CA1737/04 isolate was also tested against DE072 and found not to be serologically related. All three variant viruses were pathogenic in 1-wk-old broilers and vaccination with Mass/Conn followed by Holland/Conn provided 80% protection against the CA1737/04 virus. The 2003-04 California variant viruses were not compared with variants isolated in California during 1970s and 1980s because, to our knowledge, no genetic information is available and those viruses are no longer obtainable. This study shows that the CA557/03 virus was distantly related to the CAV-type viruses isolated in California in the early 1990s, but that none of the 2003-04 viruses were similar genetically or serologically to the CAL99-type viruses, indicating that new IBV variants continue to emerge and cause disease in commercial chickens in California.     

Approaches to pathogen-mediated resistance breeding against plum pox potyvirus in stone-fruit trees1

In a programme for developing systems which allow the transfer of foreign genes into apricot cultivars, we have tested cotyledons of immature embryos, somatic embryos and leaf discs. Apricot plants have been transformed, and then regenerated, with Agrobacterium tumefaciens strain LBA 4404 containing various binary plasmids: pBinGUSint, carrying the marker gene β-glucuronidase (GUS), and pBinPPVm, carrying the coat-protein gene of plum pox potyvirus (PPV). The marker gene GUS was used for visual evaluation of the efficiency of the transformation system. The coat-protein gene was used in the hope of introducing coat protein-mediated resistance to one of the most important stone-fruit pathogens in Europe and the Mediterranean area.     

Identification and analysis of the Georgia 98 serotype, a new serotype of infectious bronchitis virus

Twenty-five field infectious bronchitis viruses (IBVs) similar to, but genetically distinct from, the DE072 serotype were isolated from several states in the United States from 1990 through 1999 and were examined molecularly and antigenically. A 421-bp sequence in the hypervariable region of the S1 gene was examined, and phylogenetic analysis on that region indicated that these viruses are closely related but fall into unique groups. Cross-virus neutralization testing and entire S1 sequence analysis on selected isolates further confirmed that fact, and we divided the viruses into the DE072 serotype and two other unique groups. In a vaccine protection trial, the commercially available DE072 vaccine showed less than 50% protection against viruses in one of the groups. The majority of the recent isolates belong to that group and share very low antigenic relatedness to the DE072 strain as well as other serotypes of IBV. Consequently, we designated this group as a new serotype, Georgia 98. We developed a restriction fragment length polymorphism analysis that can differentiate this new serotype from all other serotypes of IBV.     

Lack of interaction between avian leukosis virus subgroup J and fowl adenovirus (FAV) in FAV-antibody-positive chickens

Unfounded field speculation has suggested that avian leukosis virus subgroup J (ALV-J) predisposes young meat-type chickens to inclusion body hepatitis caused by fowl adenovirus (FAV). To address this hypothesis, we infected 1-day-old grandparent meat-type chickens carrying maternal antibodies against FAV with a field isolate of FAV associated with inclusion body hepatitis in broilers, ALV-J, or both FAV and ALV-J. We examined the effects of FAV alone or in combination with ALV-J on the basis of clinical signs, overall mortality, growth rate, and gross and microscopic lesions. With such criteria for evaluating possible interactions, we found no significant differences in the dually infected birds in comparison with chickens that received a monovalent challenge with either FAV or ALV-J.     

浅谈牧草转基因育种研究进展

简要概述了牧草遗传转化方向及牧草转基因所取得的主要贡献,介绍了牧草遗传转化三种方法,并就今后的发展前景和转基因育种生物安全问题做了初步探讨。