优氯净对苏云金杆菌伴孢晶体消毒效果及机理的研究

苏云金杆菌(Bacillus thuringiensis,简称BT菌)的伴孢晶体被优氯净液处理后,在相差显微镜下观察,失去暗蓝色光泽,呈暗黑色,难溶于碱性缓冲液。虽能溶于昆虫的胃液,却失去致病性。用扫描电镜和SDS—聚丙烯酰胺凝胶电泳进一步研究,结果表明:优氯净能破坏伴孢晶体蛋白的一级和立体结构,使晶体蛋白失活,达到消毒的目的。消毒能力测定结果表明:1毫升0.03％有效氯优氯净液在3分钟内能消毒50微升BT菌液(3μg伴孢晶体/μl菌液)。消毒BT菌污染桑叶,用0.01％有效氯优氯净液浸泡3分钟即可。考虑到生产上的安全性,我们建议用0.05％有效氯优氯净消毒3—5分钟。     

Changes of intracellular potassium activity and membrane potential in guinea pig ventricular myocardium during superfusion with low sodium solutions and effects of low pH

AIM:To investigate the changes in intracellular potassium activity(aⁱK) and membrane potential(V_m) induced by low external sodium infusion (Low [Na]_o) and to detect the mechanisms involved and the relationship between aⁱK and V_m. METHODS:aⁱK and V_m were measured in infusion with different sodium concentrations using methods of convenient and ion selective microelectrodes in guinea pig ventricular myocardium. RESULTS:Low [Na]_o resulted in a decrease in aⁱK and an increase in V_m in a Na⁺ concentration-dependent manner.At the same time,contraction and resting potential increased, and action potential duration decreased markedly,but action potential amplitude was not affected. A change of the pH from 7.4 to 7.0 in low [Na]_o solution reduced the decrease in aⁱK, but did not affect the increase in V_m.CONCLUSION:A better linear relationship appeared between the changes in aⁱk and [Na]_o or in V_m and [Na]_o,while during each low [Na]_o the change in both aⁱK or V_m may reach a new balance level.     

An improved method for extraction of sorghum polymeric protein complexes

A method for fractionating sorghum proteins using extraction solvents and techniques designed to obtain polymeric protein structures (especially disulfide linked) was developed. Extraction and separation conditions were optimized in terms of completeness of protein extraction, sample stability, and analytical resolution. After pre-extraction of albumins and globulins, a 3-step sequential procedure involving no reducing agents was applied to ground whole sorghum flour. The three fractions obtained represented proportionally different protein polymer contents and molecular weight distribution as evidenced by comparative size exclusion chromatography. Protein composition also varied among the extracts with differences in kafirin composition and non-kafirin proteins detected in the fractions by RP-HPLC and SDS-PAGE analysis. The ability to quantify and further characterize sorghum polymeric protein complexes will be useful for additional studies linking protein structures with functionality and digestibility and variations for these properties within diverse sorghum germplasm.     

有机改良剂对温室土壤及番茄质量的影响

研究了优培-海藻生物有机肥(Y)、微生物菌肥(W)和腐植酸有机肥对日光温室土壤的理化性质、有效态微量元素含量、酶活性以及番茄品质等方面的影响,旨在探索快速、简易且廉价的土壤改良方法,为日光温室土壤改良及有机蔬菜生产提供理论依据。结果表明,不同土壤改良剂对土壤p H无显著影响,在番茄生育期内土壤p H值始终在7.0以上,没有出现酸化问题;拉秧后,除中量腐植酸有机肥(FM)外,其他各处理均能有效降低土壤EC值并达到极显著水平;各处理对提升有效态Mn、Zn和Fe含量的效果不显著,其中,仅高量腐植酸有机肥处理(FH)能同时提高开花结果盛期0~20 cm和20~40 cm土层的有效态Zn含量,与CK相比,分别增加10.8%和13.2%;不同土壤改良剂均可提高土壤脲酶和蔗糖酶活性;不同土壤改良剂对碱性磷酸酶的酶活性影响较小;微生物菌肥对酸性磷酸酶和过氧化氢酶的酶活性影响相对明显;不同土壤改良剂均能提高番茄可溶性固形物、可溶性糖、可滴定酸和维生素C的含量,其中,中量腐植酸有机肥处理提高了番茄的糖酸比。土壤改良剂可有效改善日光温室土壤特性及番茄品质。     

海藻酸钠-聚乙烯醇交联微球制备参数优化研究

采用海藻酸钠和聚乙烯醇为包埋剂，选取交联时间、海藻酸钠和聚乙烯醇用量比（SA ∶ PVA）以及海藻酸钠和聚乙烯醇的总浓度为影响因素设计L49（52×7）正交实验，探讨包埋的最佳理化条件。以包埋材料的成球效果，包埋小球的硬度、弹性及微观结构为考察指标，比较包埋小球性能，探讨包埋条件。结果发现当SA ∶ PVA为7 ∶ 3，总浓度为4％，交联时间为24 h时包埋效果最佳。     

磺胺间甲氧嘧啶钠注射液含量测定的能力比对结果分析

为加强兽药检验检测机构能力建设,进一步提升检测技术水平,组织开展了全国省级兽药检验机构磺胺间甲氧嘧啶钠注射液含量测定的能力比对。依据《中国兽药典》2020年版一部附录0701电位滴定法与永停滴定法以及中国合格评定国家认可委员会（CNAS）规定的程序进行本次能力比对。分别采用单因子方差分析法和Ss≤0.3σ准则对测试样品进行均匀性检验,采用t检验方法和■准则对样品进行稳定性考察,采用Z比分数评价各参加实验室的测试结果。参加本次能力比对的36家兽药检测实验室中,33家结果为满意,满意率91.7%。     

浅析真空转鼓过滤机的过滤效果

介绍大庆石化公司硫氰酸钠回收装置真空转鼓过滤机的结构及工作原理,重点讨论影响过滤效果的主要因素,针对进料、预涂效果和真空度等方面的影响,提出所采取的措施,来保证真空转鼓过滤机的过滤效果。     

硫酸氢钠催化合成氯乙酸异戊酯的研究

［目的］以硫酸氢钠为催化剂，由氯乙酸和异戊醇反应合成氯乙酸异戊酯。［方法］研究醇酸摩尔比、催化剂用量、反应时间、带水剂用量以及催化剂重复使用次数等因素对酯化率的影响。［结果］硫酸氢钠对氯乙酸异戊酯的合成具有良好的催化活性。用硫酸氢钠催化合成氯乙酸异戊酯的最佳反应条件为：氯乙酸0.10mol，异戊醇0.12mol，催化剂用量1.0g，带水剂正己烷用量15ml，74~98℃下反应1.5h，在此最佳条件下酯化率可达92.40%。［结论］为硫酸氢钠催化剂更好地应用于合成氯乙酸异戊酯的反应提供了科学依据。     

Effects of sodium fluoride on hepatic toxicity in adult mice and their suckling pups

In this investigation, we have evaluated the effect of sodium fluoride (NaF) on hepatic function in pregnant and lactating mice and their suckling pups. Experiments were carried out on female Wistar mice given 500 ppm sodium fluoride (226 ppm fluoride ion) in their drinking water from the 15th day of pregnancy until day 14 after delivery. All mice were sacrificed on day 14 after parturition. Our results showed a significant decrease in serum levels of total protein and albumin, a marked hypoglycaemia and a significant decline in serum cholesterol and triglyceride levels in fluoride-treated mice and their pups. Whereas globulin and biluribin levels in serum were not significantly changed by NaF treatment. On the other hand, serum transaminase activities (aspartate transaminase; alanine transaminase), which well known as markers of liver function, were elevated indicating hepatic cells’ damage after treatment with fluoride. Lipid peroxidation increased in NaF-treated mice and pups, as revealed by high liver malondialdehyde levels, while serum total antioxidant status showed a significant decline. These biochemical modifications in NaF-treated mice also correspond histologically with extensive ballooning, hepatocellular necrosis and infiltration of mononuclear cells. These effects were not observed in controls.     

Evaluation of propolis effects on some biochemical parameters in rats treated with sodium fluoride

The present study in which 42 female rats, each weighing 200−250 g, were used covered a period of 21 days. The animals were divided into six groups. The first group served as the control group, whereas Group 2 was administered propolis at a dose of 200 mg/kg/bw in drinking water for 21 days. Group 3 was first provided with normal drinking water for a period of 14 days, and was subsequently administered propolis at a dose of 200 mg/kg/bw in drinking water for 7 days. Group 4 was first given normal drinking water for 14 days, and was secondly administered 100 ppm fluoride as a sodium fluoride in drinking water for 7 days. Group 5 was first administered propolis alone at a dose of 200 mg/kg/bw in drinking water for 14 days, and was secondly administered 100 ppm fluoride in association with 200 mg/kg/bw propolis for 7 days. Finally, Group 6 was first provided with normal drinking water for 14 days, and was secondly administered 100 ppm fluoride in association 200 mg/kg/bw propolis for a period of 7 days. At the end of the 21st day, blood samples were collected from the heart of each animal into both heparinised tubes and tubes without anticoagulants. Glucose, triglyceride, cholesterol, total protein, and uric acid levels, and aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) activities in the serum, as well as malondialdehyde (MDA) levels, glutathione peroxidase (GSH-Px) in the plasma, erythrocyte superoxide dismutase (SOD) and catalase (CAT) activities were measured. When compared to the control group, statistical differences were determined to exist with respect to oxidative stress parameters which involved increase in MDA levels in Groups 4−6, decrease in SOD activity in Groups 4 and 6, increase in CAT activity in Groups 5 and 6, and decrease in GSH-Px activity in Groups 4 and 6. Furthermore, in comparison to the control group, significant differences were observed with respect to certain serum biochemical parameters, including decrease in glucose levels in Groups 5 and 6, decrease in triglyceride levels in Groups 2 and 4, decrease in cholesterol levels in Groups 2 and 5, decrease in the total protein level of Groups 4−6, decrease in the ALT activity of Groups 5 and 6, increase in the AST activity of Group 4, decrease in the ALP activity of Groups 2−6 and increase in the uric acid level of Group 2. In the groups that were administered propolis in association with fluoride, improvement was observed in some oxidative stress parameters and certain other biochemical parameters. Changes determined in the oxidative stress parameters (especially MDA and SOD) were indicative of the anti-radical activity of propolis on the free radicals generated by sodium fluoride. However, the values not drawing completely close to those of the control group can be explained with propolis not being able to completely eliminate the free radicals and the other adverse effects generated by fluoride.