Changes in water status in seedlings of six species in the Fagaceae after inoculation with Raffaelea quercivora Kubono et Shin-Ito

To clarify the differences in susceptibility of six species in the Fagaceae (Quercus crispula, Quercus serrata, Quercus acutissima, Quercus phillyraeoides, Quercus glauca, and Castanopsis cuspidata var. sieboldii) to Raffaelea quercivora, we inoculated this fungus on seven potted 5-year-old seedlings of each species, observed symptom development, and measured xylem pressure potential (XPP) after inoculation. The first death was observed on the 11th day in Q. crispula and on the 56th day in Q. serrata. The number of dead seedlings of Q. crispula and Q. serrata were five and one, respectively, whereas no mortality was observed in the other four species. The XPP of inoculated seedlings in both Q. crispula and Q. serrata decreased after inoculation. In contrast, the XPP of inoculated seedlings of the other four species remained almost the same as in the control seedlings. These results indicate that R. quercivora is pathogenic to Q. crispula and Q. serrata and that the susceptibility of the six Fagaceae species in our study differed among species.     

斑点叉尾鮰病毒对几种淡水鱼类细胞系感染性的初步研究

To study the susceptibility of multiple fresh water fish cell lines to channel catfish virus （CCV） and to evaluate and assess potentially pernicious impact of CCV on several rare and important economic fish species in China. Five cell lines established from several fish species including grass carp fins （GCF）, epithelioma papulosum cyprini （ EPC）, white sturgeon spleen （ WSS - 2 ）, chinook salmon embryo （ CHSE - 214 ） and parental control channel catfish ovary （CCO） were tested and compared for their sensitivity to CCV infection. After virns infection, test cells were characterized by cell morphology, cytopathic effect （CPE） appearance time, and infectious virus titer. Our results indicated that all these cell lines were sensitive to CCV, but at varied levels. Comparative viral challenge assays revealed that, among these five fish cell lines, GCF exhibited to be the most sensitive one to CCV infection, and infectious viral particles produced in this cell line is significantly more than that generated from parental CCO cells. EPC cells were also highly susceptible to CCV infection with a similar level of viral production as compared to CCO. Experimental data showed that all the test five cell lines were susceptible to CCV and present study suggests that CCV can be a potential pathogen to infect gYass carp, Cyprinus carpio and other fresh water fishes.     

美洲斑潜蝇寄生蜂对设施蔬菜常用农药的敏感性评价

为筛选对大棚菜豆美洲斑潜蝇寄生蜂毒性小的农药,在丽潜蝇姬小峰、潜蛾姬小峰等寄生蜂大龄幼虫至蛹期,用18种常用农药的常规剂量进行分区处理,试验结果表明:毒死蜱和联苯菊酯毒性最大,寄生蜂校正死亡率大于90%;阿维菌素中度有害,校正死亡率为55.29%;高氯、啶虫脒、哒螨灵、腈菌唑、嘧霉胺、霜脲锰锌处理的校正死亡率25%～45%;灭蝇胺、阿克泰、吡虫啉、氟硅唑、苯醚甲环唑、多菌灵、速克灵、安克、代森锰锌处理的校正死亡率则小于25%.此外,为验证药剂残留对寄生蜂的影响,调查了药后7d羽化的成蜂48h存活率,灭蝇胺处理的成蜂存活率接近90%,高氯、啶虫脒、哒螨灵、吡虫啉均在80%以上,阿维菌素为41.67%,阿克泰仅为8.33%;各杀菌剂处理药后5～7d羽化的寄生蜂48h存活率与清水对照无明显差异.     

猪源大肠杆菌的分离、鉴定及耐药性监测

为了调查京津冀地区猪致病性大肠杆菌的耐药性及流行血清型,从河北、北京、天津地区发生仔猪黄、白痢的十个猪场分离60株大肠杆菌,其中致病性大肠杆菌55株,进行了生化和血清型鉴定,并对其耐药性进行了监测与分析。结果发现：分离的猪致病性大肠杆菌优势血清型为O101、O152、O93、O78、O54,这5种血清型占总分离致病菌株的56.4%（31/55）。所分离的60株大肠杆菌药敏试验结果中抑菌作用最强的是菌必治、多粘菌素、先锋必、先锋霉素和壮观霉素,敏感率分别为95.0% (57/60)、90.0%(56/60)、88.3% (53/60)、86.7%(52/60)和85%(51/60)。耐药率较高的分别为链霉素（80%）、庆大霉素（53.3%）、氨苄青霉素（75%）复方新诺明（86.7%）、痢菌净（76.7%）、呋喃唑酮（71.2%）、诺氟沙星、环丙沙星（51.7%）、喹乙醇（75%）和洛美杀星（70%）氟苯尼考（55%）。60株大肠杆菌多数为6耐以上的菌株（80%）,其中8耐、10耐、6耐最高分别为17%、15%、12%。     

不同黄瓜品种对缺铁的敏感性研究

无土裁培条件下,研究了11个黄瓜品种对缺铁的敏感性差异,结果表明:不同黄瓜品种对缺铁的敏感性问(即铁营养效率间)存在明显差异。缺铁下,对缺铁相对不敏感的品种比相对敏感的品种的培养液pH下降早且下降幅度大;根系Fe(Ⅲ)还原力增加早且增加幅度大;植株生长量(地上部的)和植株含铁量(津春4号的)下降幅度小,表现出较高的抗缺铁能力。上述结果为无土裁培中进一步选育和利用黄瓜铁高效品种提供了一定的理论基础。     

生物农药对小十三星瓢虫的敏感性测定

在室内条件下采用喷雾法.以10%吡虫啉做对照,分别测定2种生物农药1.8%阿维菌素乳油、1%苦参碱可溶性液剂对小十三星瓢虫的敏感性试验.结果表明:供试药剂毒性大小依次为阿维菌素＞苦参碱＞吡虫啉(对照药剂).阿维菌素的毒力最高为LG50 3.71807 mg/L是对照药剂的3.96倍,其次苦参碱LG50 4.18463 mg/L是对照药剂的3.52倍,说明生物农药对小十三星瓢虫比较敏感,生物农药毒力高于对照药剂吡虫啉(新烟碱类)的毒力.     

新疆石河子奶牛隐性乳房炎源金黄色葡萄球菌的分离鉴定及药物敏感性分析

为了解石河子地区部分规模化奶牛场奶牛隐性乳房炎源金黄色葡萄球菌的生物学特性及药物敏感性,为科学防治该病的发生提供参考依据,本试验选择了石河子周边地区不同规模的11个奶牛场,通过采用LMT法检测其隐性乳房炎的感染率,并从采集到的313份隐性乳房炎奶样中分离鉴定金黄色葡萄球菌,同时采用纸片扩散法（K－B法）对分离株的药物敏感性进行了分析。结果表明,试验区奶牛隐性乳房炎的总阳性率为44．56％（869／1950）,金黄色葡萄球菌的分离率为44．71％（93／208）;药敏试验结果表明,大部分菌株对阿莫西林、红霉素、四环素表现为高度耐药,耐药率分别为92．30％（24／26）、80．77％（21／26）、80．77％（21／26）;对庆大霉素、氧氟沙星、头孢唑啉表现为敏感,敏感率分别为57．70％（15／26）、76．92％（20／26）、76．92％（20／26）;部分菌株对克林霉素中度敏感,敏感率为46．15％（12／26）。建议在选用抗生素治疗奶牛隐性乳房炎时,以流行菌株的药物敏感性为依据。     

Navelina ISA 315: A cultivar resistant to citrus variegated chlorosis

Citrus variegated chlorosis (CVC), caused by Xylella fastidiosa, is a bacterial disease of great importance to the Brazilian citrus industry. CVC is transmitted by grafting and by leafhoppers of the Cicadellidae and Cercopidae families. There is little information about CVC tolerant sweet orange cultivars (Citrus sinensis L. Osbeck). However, previous studies have indicated some resistance to CVC in the ‘Navelina ISA 315’ cultivar. Based on such information, this study has been carried out to determine the resistance of ‘Navelina ISA 315’ to CVC observing disease symptoms in the field and in the greenhouse, associated with the presence and quantitation of X. fastidiosa in plant tissue by PCR and quantitative real time PCR (qPCR). In agreement with previous information, the results show that ‘Navelina ISA 315’ is resistant to CVC, on the grounds that almost no symptoms and low bacterial concentrations were found.