伪狂犬病病毒立即早期蛋白基因缺失突变体对SV40启动子的调控作用

用多次PCR方法对伪狂犬病病毒的立即早期蛋白(immediate early protein，IE180)基因进行部分缺失。测序证实缺失序列正确后，构建了IE180基因部分缺失突变体的真核细胞表达裁体peP1P2、pcP1P3P2、pcP6P2。将这些真核表达裁体与带有SV40早期基因启动子和报告基因CAT(氯霉素乙酰转移酶)的pCAT3-control载体质粒混合后，用质酯体介导的方法，共转染Hela细胞。通过CAT的ELISA方法检测瞬时表达结果表明：突变体P1P2和P1P3P2对SV40启动子具有较强的激活能力，而P6P2则对SV40启动子有较明显的抑制作用。     

农业科研单位干部挂职模式探讨

干部挂职是锻炼培养干部、加强信息交流、强化服务意识的一种有效途径,农业科研单位开展干部挂职工作,有助于优化科技人才队伍结构、更新管理理念和创新管理体制。文章通过总结目前干部挂职工作模式中存在的问题,结合农业科研单位的特点,提出了适合农业科研单位干部挂职的模式,并对农业科研单位干部挂职工作提出了建议,如加强思想教育工作、合理编制干部挂职工作规则、拓宽干部挂职培养途径等。     

施肥模式及栽插密度对四川丘区水稻生长及产量的影响

为探究施肥模式和栽插密度对四川丘区水稻产量及生长的影响,以'蜀优217'和'天优湘99'为材料,采用裂区设计,主区为施肥模式,裂区为栽插密度,探究不同处理对四川丘区水稻生长及产量的影响.结果 表明,侧深施肥能有效提升水稻产量,不同品种之间存在一定差异,侧深施肥模式下,'蜀优217'适宜较高的栽插密度,而'天优湘99'栽...     

碱溶性黑木耳多糖的分离、纯化和表征

为了比较系统地研究黑木耳中水不溶性物质的成份及生物活性,利用稀碱提取、ＣＰＣ纯化等方法,提取一种碱溶性黑木耳多糖,并进行系列理化性质研究。结果表明,该多糖纯度较高,不含蛋白质核酸等含氮成份,由葡萄糖,甘露糖,木糖,岩藻糖等单糖组成,数均分子量为３．１×１０＾５。     

森林可持续经营问题探讨

阐述了森林可持续经营提出的背景；论述了保持森林生态系统的生产力可再生能力，维护森林生态系统健康以及保护生物多样性是森林可持续经营的三个关键因素；并提出了实现森林可持续经营主要对策。     

中国海带产业及国际贸易情况分析

海带作为中国重要的经济型海藻,在国内水产行业中占有重要地位,中国海带出口遍及全球88个国家和地区。对联合国粮食及农业组织全球海带产区、产量及贸易情况进行系统性分析,对2006—2011年中国海带进出口贸易数据进行整理和分析,对中国海带养殖的产量、进出口格局和国际贸易情况等进行了归纳,并对比分析了中国海带产品的国际贸易量和数额变动,最后就中国海带国际贸易的未来发展提出了对策建议。     

柴油机DPF喷油助燃再生特性试验研究

柴油机微粒捕集器(DPF)是目前处理微粒排放最为有效的后处理装置之一,DPF的再生问题一直是研究的热点。针对DPF喷油助燃方式,通过发动机台架试验,研究柴油机不同喷油助燃参数对DPF再生过程的影响。研究结果表明:在柴油机微粒捕集器再生过程中,不同的油气比、喷油压力、喷油率对DPF载体峰值温度的影响不同。载体的温升速率和峰值温度随着油气比、喷油压力、喷油率的增大而增大,但进一步提高油气比,空气流量增加导致热量的对流散失作用增强,以及喷油率的进一步提高,DPF载体内氧含量不足,导致峰值温度下降。     

A Study on the antibacterial mechanism of thymol against Aeromonas hydrophila in vitro

As a zoonotic pathogen, Aeromonas hydrophila (A. hydrophila) not only has important economic significance in aquaculture but also plays an important role in global public health. With the abuse of antibiotics, the drug resistance of A. hydrophila has greatly increased, causing a poor therapeutic effect. It is particularly important to develop antibiotics alternatives against resistant bacteria. Thymol, a natural monoterpene phenolic compound, has been reported to have a variety of pharmacological effects. In this study, the effects of thymol on A. hydrophila were evaluated. The MIC and MBC of thymol to A. hydrophila were 128 μg/mL and 256 μg/mL, respectively. The results of the electron microscope showed that the bacterial cells contracted and deformed, the cell membrane was destroyed, and the cytoplasm was lost when treated with 2MIC thymol. Compared with the control group, the conductivity and the amount of DNA leakage of bacteria treated with 2MIC thymol increased by 2.45% and 66.4 μg/mL, respectively. In addition, LDH activity decreased by 25.93% after 2MIC thymol treatment. DAPI staining results showed that the intensity and quantity of fluorescence were significantly decreased in the drug treatment group. In summary, the antibacterial mechanism of thymol was to destroy the integrity of the cell membrane, make intracellular material exudate, and eventually lead to the death of bacteria. Thymol has the potential to be an antibiotics alternative against resistant bacteria.

     

1株有固氮能力的甘蔗克雷伯氏菌的分离鉴定及固氮特性

采用无氮Dbereiner培养基,从广西本地甘蔗品种桂糖28号根系分离筛选到1株高固氮活性的细菌菌株L03,对其进行形态、生理生化、16SrDNA序列的系统发育分析和固氮特性研究。结果表明,L03为植生克雷伯氏菌(Klebsiella plantica),将该菌用蛋白胨含量为0.4g/L的Dbereiner培养基培养,当培养瓶中O2含量为2mL、温度为33℃的条件下固氮活性最高,固氮百分率达29.2%。并在连续继代13次后保持固氮能力不变。     

Effects of biochars derived from different feedstocks and pyrolysis temperatures on soil physical and hydraulic properties

Purpose

Biochar addition to soils potentially affects various soil properties, and these effects are dependent on biochars derived from different feedstock materials and pyrolysis processes. The objective of this study was to investigate the effects of amendment of different biochars on soil physical and hydraulic properties.

Materials and methods

Biochars were produced with dairy manure and woodchip at temperatures of 300, 500, and 700 °C, respectively. Each biochar was mixed at 5 % (w/w) with a forest soil, and the mixture was incubated for 180 days, during which soil physical and hydraulic properties were measured.

Results and discussion

Results showed that the biochar addition significantly enhanced the formation of soil macroaggregates at the early incubation time. The biochar application significantly reduced soil bulk density, increased the amount of soil organic matter, and stimulated microbial activity at the early incubation stage. Saturated hydraulic conductivities of the soil with biochars, especially produced at high pyrolysis temperature, were higher than those without biochars on the sampling days. The treatments with woodchip biochars resulted in higher saturated hydraulic conductivities than the dairy manure biochar treatments. Biochar applications improved water retention capacity, with stronger effects by biochars produced at higher pyrolysis temperatures. At the same suction, the soil with woodchip biochars possessed higher water content than that with the dairy manure biochars.

Conclusions

Biochar addition significantly affected the soil physical and hydraulic properties. The effects were different with biochars derived from different feedstock materials and pyrolysis temperatures.