Acaricidal activity of extracts of neem (Azadirachta indica) oil against the larvae of the rabbit mite Sarcoptes scabiei var. cuniculi in vitro

The acaricidal activity of the petroleum ether extract, the chloroform extract and the acetic ether extract of neem (Azadirachta indica) oil against Sarcoptes scabiei var. cuniculi larvae was tested in vitro. A complementary log-log (CLL) model was used to analyze the data of the toxicity tests. The results showed that at all test time points, the petroleum ether extract demonstrated the highest activity against the larvae of S. scabiei var. cuniculi, while the activities of the chloroform extract and the acetic ether extract were similar. The activities of both the petroleum ether extract and the chloroform extract against the larvae showed the relation of time and concentration dependent. The median lethal concentration (LC(50)) of the petroleum ether extract (1.3muL/mL) was about three times that of the chloroform extract (4.1muL/mL) at 24h post-treatment. At the concentrations of 500.0muL/mL, the median lethal time (LT(50)) of the petroleum ether extract and the chloroform extract was 8.4 and 9.6h, respectively.     

食盐在饲料中添加对斑点叉尾鮰生长的影响

试验以平均体重30.6g的斑点叉尾鮰为试验鱼,分别在饲料中加入0、3和6g/kg的食盐,经过80d的养殖试验所得出的结果显示,6g/kg食盐组与对照组比较,增重率提高了6.95%;3、6g/kg食盐组饵料系数与对照组比较分别下降4%、5.71%。各试验组鱼体肥满度均高于对照组1.48%;同时内脏重与体重比值分别下降13.49%和0.62%;肝胰脏重与体重比值3g/kg食盐组较对照组降低6.09%,而6g/kg食盐组则较对照组上升3.48%。各试验组鱼体血清GOT分别较对照组降低17.73%和4.94%。6g/kg食盐组背部皮肤酪氨酸酶活力较对照组上升132%,而3g/kg食盐组则下降64%;同时,3g/kg食盐组和6g/kg食盐组鱼体皮肤粘液SOD酶活力分别上升2.57%和5.86%。试验结果表明,在饲料中添加6g/kg食盐对鱼体增重率和饲料利用效率均有明显的提高,有提高鱼体肥满度而降低内脏重与体重比和肝胰脏重与体重比的作用;对鱼类的非特异免疫力和黑色素的形成有较好的促进作用。     

犬新孢子虫NcSRS2基因原核表达质粒的构建

根据已发表的犬新孢子虫NcSRS2基因序列,设计1对含有EcoRⅠ和NotⅠ酶切位点的引物。以提取犬新孢子虫虫体基因组DNA为模板,应用PCR扩增获得NcSRS2 ORF基因片段,将此基因片段克隆到pMD18-T Simple载体上,用EcoRⅠ和NotⅠ双酶切该片段,回收得到含有两个酶切位点黏端的Nc-SRS2 ORF基因,将此基因片段克隆至相同酶切回收后的PGEM-4T-2原核表达载体中,获得重组质粒pGEX-NcSRS2,经PCR鉴定,限制性内切酶分析和克隆片段序列测定比较,证实了重组质粒的正确性。     

Advances on Detection Methods for Residues of Nitrofurans in Food

Nitrofurans are broad-spectrum antibiotics which have been widely used in food animals to the prevention and treatment of gastrointestinal infections.Due to abuse of drugs by criminals,animals could produce drug-resistant strains,which reduces the role of antibiotics.Meanwhile,excessive drugs residues in food has carcinogenic,teratogenic and mutagenic effects to the human body.In this paper,the damage and the detection methods of the residues of the nitrofurans in food are surveyed.The main detection methods include high performance liquid chromatography,liquid chromatography-mass spectrometry,liquid chromatography tandem mass spectrometry,enzyme-linked immunoassay,colloidal gold immunoassay and fluorescence immunity analysis method.The research status of various detection methods are summarized and the suggestions for further research are put forward.It is expected to provide reference for future research.     

丰宁县森林食品资源现状及开发利用前景

随着科学技术的进步、人类生活水平的提高,天然绿色食品受到人们的青睐。森林经济植物种源丰富,其可食部分的营养价值及微量元素有的优于栽培植物,开发利用前景广阔。1989年,丰宁林业局同原北京林学院等单位联合,对丰宁森林木本植物资源进行了清查,摸清了种源分布,为合理?..     

乌桕金带蛾新种记述(鳞翅目:带蛾科)

本文为贵州省的重要林木害虫－乌桕金带蛾的新种记述，与近缘种中华金带蛾详加比较，附有特征图以兹鉴别。     

免疫抑制对苏拉灭和贝尼尔治疗小鼠伊氏锥虫病疗效的影响

用从自然感染宿主分离的伊氏锥虫原种ＪＧ的克隆ＪＧｍｃ１和ＪＧｍｃ５感染免疫活性正常小鼠和免疫抑制小鼠，２４ｈ后，以苏拉灭或贝尼尔治疗，两种药物对免疫抑制小鼠的ＣＤ１００均明显高于免疫活性正常小鼠，由经受一次苏拉灭或贝尼尔治疗未愈的免疫抑制小鼠分离的锥虫，感染免疫活性正常小鼠，再用原来对该克隆感染的免疫活性正常小鼠ＣＤ１００的苏拉灭或贝尼尔治疗即无效。用免疫溶解试验分别测定一组免疫抑制和免疫活性正确     

蝗虫痘病毒对黄胫小车蝗生长发育和产卵力的影响

试验观察结果表明,蝗虫痘病毒除对黄胫小车蝗有显著致死作用外,使感病寄主在接种13～33d后,食量比对照减少28.73%～70.40 %导致生长发育缓慢,接种后13～18d,对照组生长率为36.3mg/d,而处理组则分别为14.9、14.5和9.6mg/d,仅为对照的1/4～1/2。寄主羽化极不整齐,对照组整个历期只有5d,而处理组则为16～46d,随着接种剂量的加大,这种“拖延”趋势越发明显。寄主产卵量明显降低,甚至根本不能产卵。处理组寄主“畸形”和“自相残杀”的情况也较对照组严重。     

A cluster of two psittacosis cases among women farmers exposed to Chlamydia psittaci-infected domestic poultry in Zhejiang Province,China

A cluster of Chlamydia psittaci (C. psittaci) cases was reported in Zhejiang Province, China, 2019. This study evaluates the extent of the outbreak and determines the source of infection. Real-time PCR and sequencing of the ompA gene of C. psittaci were performed to identify the cases, the domesticated poultry and close contacts. The index patient was a 76-year-old woman with chronic vertigo, and Case 2 was a 64-year-old female farmer with herpes zoster. Both women bought psittaci-infected chickens or ducks from the same mobile street vendor and raised them for 10 days and 23 days before fever onset. There were no direct contact between the two women. C. psittaci test was positive for the two patients, one sick chicken, three healthy ducks and the vendor's chicken cage. Phylogenetic analysis showed that all seven C. psittaci positive samples carried identical ompA genotype A of C. psittaci. Of all of the patients' 148 close contacts, none tested positive for C. psittaci, or developed acute respiratory symptoms. Both patients were discharged after a 4-week hospital stay. In conclusion, the source of this cluster was the poultry infected with C. psittaci, which occasionally cause infections in farmers, but inter-human transmission seems unlikely.     

Spatiotemporal heterogeneity of PPARγ expression in porcine uteroplacenta for regulating of placental angiogenesis through VEGF-mediated signalling

Non-infectious prenatal mortality severely affects the porcine industry, with pathological placentation as a likely key reason. Previous studies have demonstrated that peroxisome proliferator-activated receptor gamma (PPARγ) deficiency causes defects in the uteroplacental vasculature and induces embryonic losses in mice. However, its role in porcine placental angiogenesis remains unclear. In the present study, PPARγ expression was investigated in porcine uteroplacental tissues at gestational day (GD) 25, GD40 and GD70 via quantitative polymerase chain reaction (qPCR), Western blot and immunohistochemistry (IHC). Moreover, the roles of PPARγ in porcine placental angiogenesis were investigated using a cell model of porcine umbilical vein endothelial cells (PUVECs) to conduct proliferation, migration and tube formation assays in vitro and a mouse xenograft model to assess capillary formation in vivo. The results showed that PPARγ was mainly located in the glandular epithelium, trophoblast, amniotic chorion epithelium and vascular endothelium, as indicated by the higher expression levels at GD25 and GD40 than at GD70 in endometrium and by higher expression levels at GD40 and GD70 than at GD25 in placenta. Moreover, PPARγ expression was significantly downregulated in placenta with dead foetus. In PUVECs, knocking out PPARγ significantly inhibited proliferation, migration and tube formation in vitro and inhibited capillary formation in mouse xenografts in vivo by blocking S-phase, promoting apoptosis and downregulating the angiogenic factors of VEGF and its receptors. Overall, the spatiotemporal heterogeneity of PPARγ expression in porcine uteroplacental tissue suggests its vital role in endometrial remodelling and placental angiogenesis, and PPARγ regulates placental angiogenesis through VEGF-mediated signalling.