苯并芘对猪卵母细胞SHH信号通路影响的研究

如今空气污染问题仍广泛存在,其中苯并芘（Benzo （a） pyrene,BaP）是一种常见的空气污染物,对人和动物的健康具有严重影响。据报道,BaP可以显著降低卵母细胞IVM （卵母细胞体外成熟）能力,但机制尚不清楚。因此,本研究在猪卵母细胞IVM培养液中添加不同浓度BaP （50 μM、100 μM、200 μM）检测其对卵母细胞IVM能力的影响,并检测此过程SHH信号通路相关基因和蛋白的表达。结果显示50 μM BaP处理组卵母细胞IVM能力显著低于对照组（76.5 vs 68.1,P<0.05）,并随着BaP浓度增加进一步下降。同时,qPCR和免疫荧光染色检测发现,50 μM BaP处理组卵母细胞中SHH信号通路相关基因mRNA和蛋白表达量,均显著低于对照组（P<0.05）。因此,本研究初步证明BaP可能通过破坏SHH信号通路降低猪卵母细胞IVM能力。     

供油提前角对甲醇发动机性能及排放的影响

利用在缸内加装电热塞的ZS1115单缸柴油,实现纯甲醇(M100)燃料的扩散燃烧,利用柴油机热效率高的优点,提高甲醇燃料的能量转换效率。通过改变供油提前角,研究不同供油提前角对甲醇发动机性能及排放的影响,并与原单缸柴油机燃用0#柴油进行对比。试验结果表明:供油提前角对甲醇发动机动力性、经济性及排放均有影响。与原机燃用0#柴油相比,燃油消耗率上升,使用成本降低;HC排放量升高,CO和NOX排放量降低。供油提前角提前4°CA时CO排放最少,最低平均减少23.89%;供油提前角退后2°CA时NOX排放最少,最低平均减少94.74%。     

黄淮海地区大豆生产机械化现状与发展趋势

机械化在大豆全程生产中发挥着重要作用。为此,针对黄淮海地区大豆机械化生产现状,分析了目前大豆机械化生产中存在的问题,对大豆产业发展,从"种子处理技术""机械化精密平播免中耕技术""科学施肥,合理使用杀虫剂和除草剂""大力推广大豆机械化收获技术"等方面简要阐述黄淮海地区大豆生产全程机械化的发展趋势。     

宽幅高效离心式双圆盘撒肥机设计与试验

为解决现有水旱田撒肥机械作业效率低、撒肥量调节技术落后、施肥均匀性稳定性差等实际问题,设计了一种同轴驱动的离心式双圆盘撒肥机。介绍了整机结构与工作参数,研究设计了撒肥传动系统、撒肥盘结构、排肥量液压调节装置等,并确定了关键结构和参数,同时进行了试验研究。试验结果显示,推肥板推肥角度-20°~30°可调,撒肥幅宽达到50m,总排肥量稳定性变异系数低于6%,施肥均匀性变异系数低于16%。研究结果表明,撒肥机工作性能稳定、撒肥量可控、抛撒均匀,整机设计满足水旱田宽幅高效撒肥作业要求。     

Comparison of emission estimates for non‐CO2 greenhouse gases from livestock and poultry in Korea from 1990 to 2010

It has often been claimed that non‐carbon dioxide greenhouse gases (NCGGs), such as methane, nitrous oxide and fluorinated greenhouse gases, are significant contributors to climate change. Here we nvestigate emission estimates of methane and nitrous oxide from livestock and poultry production, which is recognized as a major source of those NCGGs, in Korea over the period of 1990 through 2010. Based on the data on livestock and poultry populations, emission estimates of methane and nitrous oxide are first derived based on the Tier 1 approach. Then, the Tier 2 approach is adopted to obtain emission estimates of methane and nitrous oxide from cattle, which are known to be the largest sources of these NCGGs and account for about 70% of emissions from livestock and poultry in Korea. The result indicates that the Tier 2 estimates of methane and nitrous oxide emissions from enteric fermentation and manure management are significantly different from the Tier 1 estimates over the analysis period.     

Isolation and characterization of antimicrobial-resistant Escherichia coli from national horse racetracks and private horse-riding courses in Korea

Limited information is available regarding horse-associated antimicrobial resistant (AR) Escherichia (E.) coli. This study was designed to evaluate the frequency and characterize the pattern of AR E. coli from healthy horse-associated samples. A total of 143 E. coli (4.6%) were isolated from 3,078 samples collected from three national racetracks and 14 private horse-riding courses in Korea. Thirty of the E. coli isolates (21%) showed antimicrobial resistance to at least one antimicrobial agent, and four of the AR E. coli (13.3%) were defined as multi-drug resistance. Most of the AR E. coli harbored AR genes corresponding to their antimicrobial resistance phenotypes. Four of the AR E. coli carried class 1 integrase gene (intI1), a gene associated with multi-drug resistance. Pulsed-field gel electrophoretic analysis showed no genetic relatedness among AR E. coli isolated from different facilities; however, cross-transmissions between horses or horses and environments were detected in two facilities. Although cross-transmission of AR E. coli in horses and their environments was generally low, our study suggests a risk of transmission of AR bacteria between horses and humans. Further studies are needed to evaluate the risk of possible transmission of horse-associated AR bacteria to human communities through horse riders and horse-care workers.     

Apparent ileal digestibility of nutrients and amino acids in soybean meal,fish meal,spray‐dried plasma protein and fermented soybean meal to weaned pigs

This study sought to determine whether fermentation could increase apparent ileal digestibility (AID) of dry matter (DM), nitrogen (N), energy (E) and amino acids (AA) in fermented soybean meal (FSBM) greater than that of soybean meal (SBM) in weaned pigs. Four weaned pigs (10.00 ± 0.30 kg) were surgically equipped with T‐cannulas and randomly followed a 4 × 4 Latin square design of treatments (SBM, FSBM, fish meal and spray‐dried plasma protein). Overall, the fermentation process was able to reduce the amount of anti‐nutritional factors (ANF), including trypsin inhibitors, raffinose and stachyose, in the FSBM diet, which were significantly reduced by 39.4, 92.2, and 92.9%, respectively, as compared to the SBM diet. As a consequence of ANF reduction in FSBM, the AID of DM, N and E as well as AA was significantly greater with FSBM than SBM. Taken all together, the fermentation process improved the nutritional quality of SBM, due to ANF reduction, leading to improvement of digestibility of AA. As such, FSBM can be potentially used as a specialized feed ingredient, especially for young animal diets in an attempt to reduce diet costs.     

Generation of Salmonella ghost cells expressing fimbrial antigens of enterotoxigenic Escherichia coli and evaluation of their antigenicity in a murine model

Salmonella Typhimurium ghost cells expressing K88ab, K88ac, K99, and FasA fimbriae of enterotoxigenic Escherichia coli (ETEC) in their envelopes were constructed. The genes encoding the fimbriae were individually cloned into an expression plasmid, pMMP81, carrying the asd gene, which was subsequently electroporated into the Δasd S. Typhimurium mutant. Plasmid pJHLP99, carrying the phiX174 lysis gene E, was also subsequently electroporated into the Salmonella mutant. The presence of the individual fimbriae on the ghost cells was examined by Western blot analysis. Forty BALB/c mice were equally divided into 2 groups of 20 mice each. Group A mice were intramuscularly vaccinated with a mixture of the 4 ghost cells expressing the individual fimbriae. The group B mice were inoculated with sterile phosphate-buffered saline as a control. The antigen-specific serum IgG concentrations were significantly higher in group A than in group B from week 2 until week 6 after inoculation. In addition, the antigen-specific IgA concentrations in fecal samples were significantly higher in group A than in group B at week 2 after inoculation. A large difference between the groups in the number of antigen-specific IgA-secreting cells in the small intestine was observed by immunohistochemical study. Also, the splenic lymphocyte proliferative responses were significantly greater in group A than in the control mice. These results suggest that vaccination with our Salmonella ghost cells can induce both humoral and cell-mediated immune responses and that the increased number of antigen-specific IgA-secreting cells in the small intestine may be correlated with the elevated fecal IgA immune response.     

不同遮荫棚下农田人参叶片开花期气体交换特性的研究

以3年生人参为试材,设置4种遮荫棚处理(P1M1:拱形棚覆盖蓝色棚膜;P1M2:拱形棚覆盖黄色棚膜;P2M1:梯形棚覆盖蓝色棚膜;P2M2:梯形棚覆盖黄色棚膜),采用Li-6400便携式光合测定系统测定不同遮荫棚处理下人参叶片的相关光合参数,研究了开花期不同遮荫棚处理对人参叶片气体交换特性的影响,以期确定农田人参的最佳遮阴栽培方式。结果表明:农田人参叶片在开花期净光合速率处于高稳时期,不同遮荫棚下农田人参叶片净光合速率具有显著差异,表现为P1M1处理叶片净光合速率最高,P2M1处理次之,P2M2处理最低。蒸腾速率、水分利用效率和表观叶肉导度变化趋势与净光合速率相同。说明在拱形棚覆盖蓝色棚膜下,农田人参叶片光合代谢较强,有利于其生长,为农田人参最佳遮阴方式。