蜱传性疾病--莱姆病螺旋体研究进展

莱姆病是一种蜱传性人兽共患病,在我国北方各省广泛流行,其病原体为伯氏疏螺旋体。莱姆病可使皮肤、心脏、关节和神经系统等多种组织器官受损。本文综述了莱姆病螺旋体的形态、种下分类、生化特征、传播媒介和贮存宿主等方面的研究进展"     

中药制剂防治肉鸡肾性传染性支气管炎的实验研究

将某养殖场已确诊为肾性传染性支气管炎的25日龄肉鸡300只，随机分为6组，应用研制的复方中药制剂——禽速康口服液按不同剂量组合进行治疗试验。结果表明，禽速康(3mL／kg)与肾舒宝(40mg／kg)联合疗法，对内鸡肾性传染性支气管炎有较好的疗效，用药3d可控制发病鸡死亡，治愈率达82％。经大群推广试验表明，禽速康与肾舒宝联合防治肉鸡肾性传染性支气管炎，效果确实，防治有效率达93．75％。     

喀斯特山区草地施肥对放牧乌蒙半细毛羊抗氧化系统功能的影响

为选择草地施肥的肥料种类,减少施肥对乌蒙半细毛羊产业的影响,在威宁县凉水沟种羊场多年生人工草地开展施肥和放牧试验。 结果表明:凉水沟种羊场人工草地牧草铜含量相对较低,但仍高于乌蒙半细毛羊营养需要标准;施肥极显著增加牧草氮含量(P<0.01),各施肥处理之间没有明显差异。硫酸铵施肥显著增加牧草硫和锌含量(P<0.01),显著降低了牧草硒的含量(P<0.01)。放牧试验结束时,施硫酸铵草地的乌蒙半细毛羊血液中铜、铁和硒的含量极显著低于施硝酸铵草地和对照组(P<0.01), 动物血液锌和硫含量极显著高于硝酸铵施肥牧场和对照组(P<0.01)。硫酸铵施肥牧场的乌蒙半细毛羊血红蛋白、红细胞压积容量极显著低于硝酸铵施肥牧场和对照牧场(P<0.01),血清铜蓝蛋白含量、血清超氧化物歧化酶活力、血清谷胱甘肽过氧化物酶活力和血清过氧化氢酶等抗氧化酶的活力极显著低于硝酸铵施肥牧场和对照牧场(P<0.01),丙二醛的含量显著高于硝酸铵施肥牧场和对照牧场(P<0.01)。血液其他矿质元素和血液指标及血清生化值在2个施肥处理和对照之间均差异不显著。 因此得出结论,草地施肥的种类需要根据土壤矿物质分布和含量情况确定,铜含量低的牧场不适合硫酸铵施肥,硫酸铵施肥明显影响了乌蒙半细毛羊机体抗氧化系统功能。     

微白黄链霉菌对红豆草壳二孢的拮抗效果评价

红豆草壳二孢叶斑黑茎病(Ascochyta onobrychidis)是红豆草(Onobrychis viciaefolia)最重要的病害之一,在分离此病菌的同时得到一种对此病菌具有较强抑制作用的微生物,为评价此拮抗菌的开发利用前景,本研究采用形态学、分子生物学和生物化学方法鉴定了其分类地位,并测定了其对红豆草壳二孢的抑菌效果。通过构建系统发育树并结合其形态特征和生理生化特性,将该拮抗菌鉴定为微白黄链霉菌(Streptomyces albidoflavu),在高氏一号培养基上菌落为黄白色,可产生黄白色水溶性色素,孢子丝钩状,顶端螺旋形;在平板对峙试验中该菌的菌落对红豆草壳二孢菌落的相对抑制率达74.33%,同时该菌发酵液对红豆草壳二孢菌丝生长和孢子萌发的抑制率分别为80.95%和93.87%。该菌具有生物防治红豆草壳二孢的开发和利用价值。     

新疆乌鲁木齐市犬布鲁氏菌病流行病学调查

为了解新疆乌鲁木齐市犬布鲁氏菌病流行特征,分析犬感染风险因素,初步掌握养犬人员对布鲁氏菌病的认知程度和行为特点,从而提出合理的预防对策和控制措施,采用流行病学横断面研究方法,通过估计流行率计算抽样数量,然后随机抽样,采用IELISA方法检测光滑型和粗糙型犬布鲁氏菌,同时结合调查问卷,获得乌鲁木齐市犬布鲁氏菌病流行率、感染风险因素和养犬人员对布鲁氏菌病认知情况,并对调查结果采用SPSS和Excel软件进行数据统计分析。结果显示:乌鲁木齐市犬布鲁氏菌病总流行率为25.5%(95%CI:20.9%~30.1%),且犬种和牛羊种并存,公共卫生威胁严重;从不同群体看,牧区流行率最高,为41.5%(95%CI:31.0%~52.0%);外购、散养、常接触牛羊、喂生肉、不处理犬粪便等行为是乌鲁木齐市犬布鲁氏菌感染的潜在风险因素,其中"常接触牛羊"(OR=1.97,95%CI:1.47~15.35)、"喂生肉"(OR=5.06,95%CI:1.69~20.74)是主要风险因素;乌鲁木齐市养犬人员对布鲁氏菌病的认知程度低,个人防护意识差。因此,应加强对犬感染牛羊种布鲁氏菌的公共卫生防控,减少犬与牛羊的直接接触,不喂生肉,定期开展犬布鲁氏菌病专项检测,同时加强宣传,提高养犬人员的布鲁氏菌病认知度。     

‘紫罗兰’白菜叶片再生体系的建立

以‘紫罗兰’白菜无菌苗叶片为外植体,研究了不同6-BA和NAA浓度组合对白菜真叶不定芽再生的影响,同时采用不同生根培养基对再生芽进行生根诱导。结果表明:诱导‘紫罗兰’白菜真叶分化的适宜培养基为MS+2mg/L 6-BA+1mg/L NAA+4mg/L AgNO3,每个外植体平均再生芽数为1.42个;生根培养基以MS+0.5mg/L NAA最佳,平均每个不定芽诱导根数为16.54个。该试验结果为‘紫罗兰’白菜材料的快速繁殖提供了理论和技术参考。     

火龙果镰刀菌果腐病病原菌鉴定及生物学特性研究

采用形态学特征观察、rDNA-ITS序列、EF-1α序列比对和系统发育树分析的方法对引起火龙果镰刀菌果腐病病原菌进行鉴定,并初步研究其生物学特性。结果表明:引起火龙果镰刀菌果腐病是单隔镰刀菌(Fusarium dimerum Penzig in Saccardo),这是该菌引起火龙果果腐病在国内的首次报道。该菌菌丝生长的适宜温度25~35℃,最适温度30℃,适宜产孢温度25~35℃,最适产孢温度30~35℃,致死温度75℃(10 min);适宜pH5~9,最适pH7,最适产孢pH4;连续光照、D-果糖为碳源、牛肉膏和蛋白胨为氮源时最有利于该菌菌丝生长;完全黑暗、D-半乳糖为碳源、尿素为氮源时最有利于该菌产孢。综合分析认为,该菌耐高温,光照充足、弱酸和富含有机营养的环境有利于该菌的生长和繁殖。     

Improvements of TKC Technology Accelerate Isolation of Transgene-Free CRISPR/Cas9-Edited Rice Plants

Elimination of the CRISPR/Cas9 constructs in edited plants is a prerequisite for assessing genetic stability, conducting phenotypic characterization, and applying for commercialization of the plants. However, removal of the CRISPR/Cas9 transgenes by genetic segregation and by backcross is laborious and time consuming. We previously reported the development of the transgene killer CRISPR (TKC) technology that uses a pair of suicide genes to trigger self-elimination of the transgenes without compromising gene editing efficiency. The TKC technology enables isolation of transgene-free CRISPR-edited plants within a single generation, greatly accelerating crop improvements. Here, we presented two new TKC vectors that show great efficiency in both editing the target gene and in undergoing self-elimination of the transgenes. The new vectors replaced the CaMV35S promoter used in our previous TKC vector with two rice promoters to drive one of the suicide genes, providing advantages over our previous TKC vector under certain conditions. The vectors reported here offered more options and flexibility to conduct gene editing experiments in rice.     

Increasing selenium supply during the close-up dry period improves nutrient metabolism and attenuates inflammatory response after calving in dairy cows

The objective of this study was to investigate whether feeding selenium (Se)-replete cows a Se-yeast supplement in late pregnancy affects nutrient metabolism and inflammatory response during the periparturient period. Twenty cows were randomly assigned to two groups with 10 cows each. Cows in one group received Se-yeast at 0.3 mg Se/kg DM during the last 4 weeks before calving in addition to fed a TMR containing supplemented sodium selenite at 0.3 mg Se/kg DM (Se-yeast), while cows in another group were only fed a TMR containing supplemented sodium selenite at 0.3 mg Se/kg DM (Control). Blood samples were collected and analyzed for nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), glucose, insulin, tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, serum amyloid A (SAA), haptoglobin (Hp), and albumin. In control cows, plasma NEFA, IL-1β, IL-6, SAA, and Hp levels increased after calving, but glucose, insulin, and albumin levels decreased after parturition. Se-yeast supplemental cows had lower postpartum concentrations of NEFA, TNF-α, IL-1β, IL-6, SAA, and Hp, and higher postpartum levels of glucose, insulin, and albumin compared with control cows. The results indicate that feeding Se-replete cows a Se-yeast supplement in late pregnancy improves nutrient metabolism and attenuates the inflammatory response after calving.