无核葡萄胚发育及早期离体培养的研究:Ⅲ.培养方式对离体胚发育的影响

对5个无核葡萄品种的试验表明,不同培养方式对离体胚发育的影响是很明显的,其中4个品种胚发育率液体培养高于固体培养,‘京早晶’在液体培养中胚发育率高达73.7%,是目前国内外胚发育率最高的报道;液体培养比固体培养胚的发育程度高,发育整齐,无畸形胚,易成苗.     

Effect of dietary vitamin C and ammonia concentration on the cellular defense response of Macrobrachium nipponense

This study examined the effects of dietary vitamin C and ammonia concentration on the cellular defense response of Macrobrachium nipponese . The response of the cellular defense was determined by monitoring changes in reactive oxygen intermediates in hemocytes, superoxide dismutase activity, catalase activity, glutathione peroxidase activity, glutathione reductase and glutathione transferase activity in muscle. The results showed that prawns fed the basal diet had a significant increase in reactive oxygen intermediates in response to exposure to ammonia-N. When dietary vitamin C was added to the feed, there was a significant decrease in reactive oxygen intermediates in response to exposure to ammonia-N. Total superoxide dismutase and glutathione peroxidase activity of prawns fed the basal diet decreased as ammonia-N increased. This decrease in activity was significantly less pronounced in prawns that were fed the dietary vitamin C supplement. In prawns that were fed the dietary vitamin C supplement there was no significant variation in catalase reductase or gluxathione reductase activity in response to variations in ammonia-N concentration. The glutathione transference activity increased at a low concentration of ammonia-N in prawns that were fed the dietary vitamin C supplement, but there was no significant variation in the prawns fed the basal diet. Overall the results indicate that dietary vitamin C supplements enhance the capacity of M. nipponese to respond to elevations in ammonia-N. This response involved several biochemical reactions known to be involved in cellular defense.     

Hematological parameters and visceral lesions relationships in rabbit viral hemorrhagic disease.

Twenty rabbits were inoculated with a suspension of Viral Hemorrhagic Disease virus. Hemostatic functions were assessed every sixth hour from 6 to 60 hours post-inoculation. Tissue samples obtained at the same intervals allowed the study of the development of lesions throughout the experiment. Biological signs of Disseminated Intravascular Coagulation (DIC) were detected on and after 30 h post-inoculation and consisted of prolonged One Stage Prothrombin Time and Activated Partial Thrombin Time, the decrease of factors V, VII, and X and high levels of soluble fibrin monomer complexes and D-dimers. A reduction of thrombocyte numbers, heterophils and lymphocytes was associated. The close association of DIC and necrotizing hepatitis lesions suggested the hepatic lesions to be the most important DIC triggering factor. Other mechanisms are discussed.     

香菇原生质体工程菌株的构建研究——I.香菇原生质体的分离与再生行为

本研究通过电镜观察与酶解分析确定香菇(Lentinula edodes)菌丝细胞壁组成.并进行了双核菌丝原生质体的分离和培养.研究发现:酶解过程中,菌丝原生质体一般只从菌丝顶端等新生部位释放出来.合适的渗透剂、菌龄和酶解温度是原生质体得率的重要保证;原生质体再生菌丝过程是一个间歇性的依赖于原生质团涌动流向的过程,再生菌丝的形成经历了原生质体形成突起-哑铃状-分枝状等不同形态类型的再生阶段;再生菌丝体在形态上没有观察到锁状联合,栽培后未能结实,初步判断为单核菌株.     

秋用蚕种浸酸生产组织模式探讨

秋用蚕种浸酸是一项十分重要的生产工作,是属于环节多、参加人员多、技术处理要求严格的流水作业,如日浸酸4万张毛种,十多个生产环节,需技术人员30人左右,辅助工100多人。如何进行有效组织保证生产安全,提高蚕种质量,多年来我们进行了探索。以前我们均采用的是拉通式组织浸酸工     

Determination and kinetics of enrofloxacin and ciprofloxacin in Tra catfish (Pangasianodon hypophthalmus) and giant freshwater prawn (Macrobrachium rosenbergii) using a liquid chromatography/mass spectrometry method

Determination and kinetics of enrofloxacin and ciprofloxacin in Tra catfish (Pangasianodon hypophthalmus) and giant freshwater prawn (Macrobrachium rosenbergii) using a liquid chromatography/mass spectrometry method. J. vet. Pharmacol. Therap. 34, 142-152. The fluoroquinolones enrofloxacin (EF) and ciprofloxacin (CF) residues were investigated in the edible tissues of two important Asian aquacultured species such as Tra catfish (Pangasianodon hypophthalmus) and giant freshwater prawn (Macrobrachium rosenbergii) using a sensitive liquid chromatography-electrospray ionization-tandem mass spectrometry method. Fish and prawn were treated with medicated feed with multiple doses of EF, in field conditions. A validation study of the analytical method was realized in terms of linearity, specificity, precision (repeatability and within-laboratory reproducibility), recovery and decision limit (CCα). The time needed before the antibiotic disappears from animal tissues or reach the maximum residue limit (MRL, 100μg/kg) was assessed. The concentration values of EF detected in Tra catfish tissue were between the MRL and 2×MRL concentrations, according to the fish density, 7days following the end of the enrofloxacin treatment (20mg/kg body weight per day, for seven consecutive days). The concentration value of ER in prawn tissue was lower than the MRL and the limit of quantification (LOQ, 14μg/kg) 5 and 7days after the stop of the EF treatment (50mg/kg body weight per day, for five consecutive days), respectively. The mean detected levels of CF was much lower in comparison with that of EF, indicating that only a small part of EF is metabolized into CF (<5%) in both Tra catfish and prawn.     

烟台市规模化养猪场养殖现状调查

《国家中长期动物疫病防治规划》(2012—2020年)将疫病净化列为重点工作之一,为持续推进种畜场的疫病净化工作,2018年11—12月对烟台市32个规模化猪场养殖现状进行了摸底调查,根据养殖现状对疫病监测、疫病防控以及对疫病净化的认识和开展情况进行了现场调研。