中国国民收入与茶叶内销量的实证研究

通过Eviews31软件就1990年到2008年我国国民收入与茶叶内销售量关系进行分析，得出我国国民收入与茶叶内销量存在协整关系，同时运用格兰杰检验得出我国国民收入提高是我国茶叶内销量增加的成因，认为通过预测我国国民收入水平可推算出我国茶叶的内销量，为茶叶产销决策提供依据。     

亚成体东北虎感染巴氏杆菌死亡一例

2009年1月11日,北方森林动物园发生一起自繁自养的亚成体东北虎感染巴氏杆菌死亡病例。本病例从发病到死亡共5 d时间,病程较短,以食欲下降至废绝,饮水量不变,精神沉郁,口腔腺体分泌增多、流涎,呈滴水样,腹部疼痛感明显为特征,口服诺氟沙星和多酶片治疗无效后改用肌注头孢哌酮钠和庆大霉素治疗,3 d后出现神经症状抽搐死亡。剖检肝脏表面有大量的针尖大小黄白色点状坏死灶。根据临床症状、病理剖检和实验室检查,确诊为巴氏杆菌感染。     

热处理对2种潜伏炭疽菌生长和致病性的影响

 通过测定热处理对潜伏侵染于芒果果实中的胶胞炭疽菌(Colletotrichum gloeosporioides Penz.)和香蕉果实中的芭蕉炭疽菌[C.musae(Berk.& Curt.)Arx.]离体培养菌的生长、繁殖和致病性的影响,结果表明:当温度达55℃和60℃,时间20 min时,对菌体的生长和孢子萌发可起明显抑制或杀伤作用,并降低其致病性。2种炭疽菌中,芭蕉炭疽菌比胶胞炭疽菌对热更敏感。作者认为,果实采后热处理时,应根据果实种类和不同菌,采用不同的处理温度和时间,才能得到更好的效果。     

Colonization of Aeromonas salmonicida subsp. masoucida strains in Atlantic salmon (Salmo salar L.) during infection

Aeromonas salmonicida subsp. masoucida (ASM) is classified as atypical A. salmonicida and brought huge economic damages to the local salmonid aquaculture in China. An ASM strain named AS‐C4 was used to investigate the colonization of ASM in Atlantic salmon (Salmo salar L.) by an immersion challenge with the control group (T0, no AS‐C4), group T1 (2.67 × 10⁴ CFU/ml AS‐C4) and group T2 (2.67 × 10⁷ CFU/ml AS‐C4). The numbers of AS‐C4 copies in different fish tissues (gill, intestine, skin, blood, muscle, spleen, liver and kidney) were determined at different time points post challenge using the quantitative real‐time PCR (qRT‐PCR). AS‐C4 were detected in the gill and intestine as early as 0 hr after the challenge both in T1 and T2 groups, suggesting that the gill and intestine were probably the portals of entry of AS‐C4 into salmon. Although AS‐C4 could not be detected in the skin until 24 hr after the challenge in T1 group, it could be detected in the skin as early as 0 hr after the challenge in T2 group, indicating that the skin may also be a portal of entry of AS‐C4 into salmon. AS‐C4 was immediately detected in the blood within 3 hr after it entered the host, suggesting that AS‐C4 successfully invaded the bloodstream of fish. After AS‐C4 colonized the host, it colonized the internal tissues, such as the spleen, liver, kidney and muscle. The results of this study will contribute to the understanding of the pathogenesis of the ASM strains and give a broader understanding of the infection route of ASM in it's host, providing more information for the development of new therapeutic strategies to protect against this pathogen in aquaculture.     

Swim bladder mycosis in pretty tetra (Hemigrammus pulcher) caused by Exophiala pisciphila and Phaeophleospora hymenocallidicola,and experimental verification of pathogenicity

Spontaneous invasive and chronic disseminated mycosis affected Hemigrammus pulcher kept in a public aquarium, and infection was manifested by inappetence, exophthalmia, erratic swimming, eroded scales, anaemia of the gills and abdominal distension. Internally, there was a grossly swollen swim bladder with a thickened wall filled with a dark mass. The body cavities contained a clear, light amber fluid and a swollen intestine which was full of a watery fluid containing small gas bubbles. Histopathology revealed a granulomatous inflammatory response with fungal hyphae in the lumen and wall of the swim bladder, hepatopancreas, spleen and kidneys with signs of nephrohydrosis. Exophiala pisciphila and Phaeophleospora hymenocallidicola were isolated from the swim bladder, abdominal cavity and gastrointestinal tract. The exogenous source of infection was probably the ample wooden decoration and plants inside the aquarium. Koch's postulates were fulfilled by re‐isolation of both fungal species from fish artificially infected under laboratory conditions. As P. hymenocallidicola is less capable of defence against phagocytosis, E. pisciphila probably played a major role. Severe clinical manifestations with 100% mortality developed in two fish species infected by E. pisciphila. A significant increase in the plasma levels of amino acids was observed as a result of the activation of proteolysis.     

First description of a natural infection with spleen and kidney necrosis virus in zebrafish

Zebrafish has become a popular research model in the last years, and several diseases affecting zebrafish research facilities have been reported. However, only one case of naturally occurring viral infections was described for this species. In 2015, infectious spleen and kidney necrosis virus (ISKNV) was detected in zebrafish from a research facility in Spain. Affected fish showed lethargy, loss of appetite, abnormal swimming, distention of the coelomic cavity and, in the most severe cases, respiratory distress, pale gills and petechial haemorrhages at the base of fins. Cytomegaly was the most relevant histopathological finding in organs and tissues, sometimes associated to degenerative and necrotic changes. ISKNV belongs to the relatively newly defined genus Megalocytivirus, family Iridoviridae, comprising large, icosahedral cytoplasmic DNA viruses. This is the first case of naturally occurring Megalocytivirus infection in zebrafish research facilities, associated with morbidity. The virus has been identified based on both pathologic and genetic evidence, to better understand the pathogenesis of the infection in zebrafish and the phylogenetic relationship with other iridoviruses. Given the ability of megalocytiviruses to cross‐species boundaries, it seems necessary to implement stringent biosecurity practices as these infections may invalidate experimental data and have major impact on laboratory and cultured fish.     

Development of a continuous cell line from larval Atlantic cod (Gadus morhua) and its use in the study of the microsporidian,Loma morhua

In vitro cell culture methods are crucial for the isolation, purification and mass propagation of intracellular pathogens of aquatic organisms. Cell culture infection models can yield insights into infection mechanisms, aid in developing methods for disease mitigation and prevention, and inform commercial‐scale cultivation approaches. This study details the establishment of a larval cell line (GML‐5) from the Atlantic cod (Gadus morhua) and its use in the study of microsporidia. GML‐5 has survived over 100 passages in 8 years of culture. The line remains active and viable between 8 and 21°C in Leibovitz‐15 (L‐15) media with 10% foetal bovine serum and exhibits a myofibroblast phenotype as indicated by immuno‐positive results for vimentin, α‐smooth muscle actin, collagen I and S‐100 proteins, while being desmin‐negative. GML‐5 supports the infection and development of two microsporidian parasites, an opportunistic generalist (Anncaliia algerae) and cod‐specific Loma morhua. Using GML‐5, spore germination and proliferation of L. morhua was found to require exposure to basic pH and cool incubation temperatures (8°C), in contrast to A. algerae, which required no cultural modifications. Loma morhua‐associated xenoma‐like structures were observed 2 weeks postexposure. This in vitro infection model may serve as a valuable tool for cod parasitology and aquaculture research.     

Germinate to exterminate: chemical stimulation of Spongospora subterranea resting spore germination and its potential to diminish soil inoculum

Hoagland's solution (HS), a defined nutrient supplement for plants, has been previously reported to stimulate zoospore release from resting spores of the potato pathogen Spongospora subterranea f. sp. subterranea. This study obtained direct empirical evidence for an increase in zoospore release with HS treatment, and identified Fe‐EDTA as the stimulant component of HS. Stimulation of resting spores by HS and Fe‐EDTA resulted in greater and earlier zoospore release compared to a distilled water control, and in the presence of a susceptible tomato host plant resulted in enhanced root infection. Given the labile nature of S. subterranea zoospores, it was postulated that stimulation of premature release of zoospores from the dormant resting spores in absence of susceptible hosts could reduce soil inoculum levels. In two glasshouse trials in the absence of host plants, both Fe‐EDTA and HS soil treatments reduced S. subterranea soil inoculum levels, providing proof of concept for the ‘germinate to exterminate’ approach to inoculum management.     

烟草NbbZIP28突变体的创建及其对病毒侵染胁迫的响应

【目的】bZIP类转录因子参与植物的生长发育、激素信号、抗病性及抗逆性等多种生物胁迫过程。前期研究表明黄瓜花叶病毒(Cucumber mosaic virus,CMV)或烟草花叶病毒(Tobacco mosaic virus,TMV)侵染本氏烟(Nicotiana benthamiana)上调内质网应激（endoplasmic reticulum stress,ERs）因子NbbZIP28;NbbZIP28沉默导致病毒积累量上升,本研究旨在验证NbbZIP28对病毒侵染胁迫的响应机制。【方法】通过CRISPR/Cas9基因编辑技术和烟草遗传转染创建NbbZIP28基因突变植株,以野生型植株为对照,分别浸润接种侵染性克隆TMV-GFP、摩擦接种TMV-GFP或CMV接种液,检测突变体植株对病毒侵染胁迫的敏感性变化,接种CMV后0-48 h,采用qRT-PCR检测内质网应激相关的未折叠蛋白反应（unfolded protein response,UPR)基因的表达。本氏烟接种TMV 24 h、接种CMV 48 h后,在接种叶上浸润融合蛋白NbbZIP28-GFP,瞬时表达48 h后,采用Western blot检测病毒诱导NbbZIP28蛋白的水解激活;采用在线搜索工具PlantCARE分析NbbZIP28启动子区域中参与防卫和应激反应的顺式作用元件。【结果】CRISPR/Cas9定点敲除NbbZIP28后,目的基因靶位点缺失了10个碱基,导致翻译错误、蛋白功能变化。在正常生长条件下,转基因阳性植株与野生型无显著的表型差异。植株接种TMV-GFP后4-8 d,突变体中的病毒浸润斑亮度或初侵染点数目均显著高于野生型,扩展至新叶的速度较快。接种CMV后12-48 h,突变体中UPR相关基因BiP、PDI、CAM及NbbZIP28下游基因NF-YC2的表达量显著低于野生型;5-7 d突变体中的病毒外壳蛋白（coat protein,CP）基因表达量显著高于野生型,花叶及皱缩症状更显著。蛋白质序列比对分析显示NbbZIP28具有与拟南芥AtbZIP28相同的S1P和S2P蛋白酶水解位点。Western blot检测发现,与接种清水对照相比,TMV或CMV侵染显著促进了全长的融合蛋白NbbZIP28-GFP在S1P和S2P位点发生裂解。NbbZIP28启动子序列中包含5个参与热应激反应的顺式作用元件（heat stress response element,HSE）、3个参与低温反应的顺式作用元件（low temperature response element,LTR）、1个参与防卫和应激反应的顺式作用元件（TC-rich repeats）。【结论】病毒侵染促进NbbZIP28的水解激活并上调相关的UPR基因;NbbZIP28敲除导致植株对病毒的敏感性上升,病毒诱导的UPR基因表达被抑制。NbbZIP28为病毒侵染胁迫下的UPR调控因子,在病毒侵染早期通过上调UPR信号和提高寄主基础防卫反应而延缓病毒的侵染和增殖。