设计阶段平面交叉口安全评价方法研究与应用

基于一种不依赖交通事故和交通冲突数据的事前安全评价方法——安全服务水平评价方法,分析了影响公路平面交叉口安全服务水平的客观因素,建立了设计阶段安全评价模型。结合江苏省临海高等级公路的平交口数据进行实例验证,提出了设计阶段平交口安全评价方案及优化流程,改善效果明显。     

Effects of biofloc under different carbon sources and protein levels on water quality,growth performance and immune responses in black tiger shrimp Penaeus monodon (Fabricius, 1978)

A 75‐day 2 × 3 factorial experiment was conducted to evaluate the effect of two levels of dietary protein (32 and 40%) and two different carbon sources (rice flour–R and molasses‐M), and without carbohydrate (control–C) in black tiger shrimp Penaeus monodon juveniles (3.37 ± 0.04 g) at 100 nos. m^?3 in 100 L fibre reinforced plastic tanks. Biofloc volume and total suspended solid were higher in molasses added groups (32 + M and 40 + M) followed by rice flour (32 + R and 40 + R) and controls (32C and 40C). Molasses and rice flour addition significantly reduced (P < 0.01) the total ammonia–N compared to controls. The highest Vibrio, Bacillus and Lactobacillus counts were recorded in 40 + M, 32 + M and 32 + R respectively. Among the treatments, significantly higher (P < 0.01) final body weight was recorded in 40 + R (8.5 ± 0.3 g), 40 + M (7.8 ± 0.3 g) and 32 + R (7.5 ± 0.4 g) compared to control groups, 32C (6.1 ± 0.3 g), 40C (6.4 ± 0.3 g) and molasses added group, 32 + M (5.7 ± 0.4 g). Rice flour supplementation significantly increased (P < 0.01) the total haemocyte count (×10⁶ cells mL^?1) in 32 + R (45.7 ± 3.7) and 40 + R (44.3 ± 3.1) compared to controls, 32C (27.3 ± 3.4) and 40C (25.8 ± 0.9). Similarly, higher superoxide dismutase, catalase, serum protein and glucose were recorded in the rice flour added groups, 40 + R followed by 32 + R. Among the treatments, the highest level of prophenoloxidase (OD 490 nm, 0.3 ± 0.0) and survival after challenge with Vibrio harveyi (55.6%) was observed in 32 + R. The study elucidates that rice flour addition produces optimum level of biofloc with better growth and immune responses compared to molasses and control. Furthermore, rice flour addition at 32% protein level could replace 40% protein feed.     

大豆对大豆胞囊线虫侵染的应答机制研究

大豆胞囊线虫病(Heterodera glycines,soybean cyst nematode,SCN)是大豆生产上的重要病害,其特点为危害重、分布广、难防治,每年对大豆生产造成极大的损失。种植大豆抗性新品种是防治SCN目前最为有效的措施,研究大豆对SCN侵染的应答机制,是培育大豆持久抗病品种的前提,对加快抗线虫品种选育及SCN的防控具有重要的意义。本文综述了大豆对SCN侵染的组织细胞学应答机制;介绍了大豆在SCN侵染后酶系变化及酚类代谢的生理生化应答机制;从分子水平阐明了SCN侵染后大豆的基因转录变化,差异蛋白及DNA甲基化的应答机制,以期为大豆胞囊线虫病害的进一步研究与防治提供参考。     

Cloning and expression analysis of innate immune genes from red sea bream to assess different susceptibility to megalocytivirus infection

As suggested by the Office International des Epizooties (OIE), fishes belonging to the genus Oplegnathus are more sensitive to megalocytivirus infection than other fish species including red sea bream (Pagrus major). To assess the roles of the innate immune response to these different susceptibilities, we cloned the genes encoding inflammatory factors including IL‐8 and COX‐2, and the antiviral factor like Mx from red sea bream for the first time and performed phylogenetic and structural analysis. Analysed expression levels of IL‐1β, IL‐8 and COX‐2 and the antiviral factor like Mx genes performed with in vivo challenge experiment showed no difference in inflammatory gene expression or respiratory burst activity between red sea bream and rock bream (Oplegnathus fasciatus). However, the Mx gene expression levels in red sea bream were markedly higher than those in rock bream, suggesting the importance of type I interferon (IFN)‐induced proteins, particularly Mx, during megalocytivirus infection, rather than inflammation‐related genes. The in vitro challenge experiments using embryonic primary cultures derived from both fish species showed no difference in cytopathic effects (CPE), viral replication profiles, and inflammatory and Mx gene expression pattern between the two fish species.     

斑节对虾Toll9受体基因免疫功能的研究与表达分析

Toll受体蛋白(Toll receptors)是一类重要的模式识别受体,在无脊椎动物先天性免疫系统中发挥重要作用。文章对斑节对虾(Penaeus monodon)新型Toll9受体基因(Pm Toll9)进行了研究:以人源胚胎肾细胞(HEK293T)成功构建体外细胞免疫模型,通过免疫印迹方法证实Pm Toll9重组真核蛋白可在HEK293T中成功表达。双荧光素酶报告系统检测发现在200 ng转染浓度处Pm Toll9对NF-κB报告基因的激活效果显著。q RT-PCR数据证明PmToll9成功激活HEK293T细胞Toll-like receptor(TLR)信号通路,促进通路下游髓样分化因子(My D88)、肿瘤坏死因子(TNF-α)和白介素(IL-10)的上调表达,同时酶联免疫吸附测定结果证明Pm Toll9可促进TNF-α蛋白表达水平显著上调。斑节对虾体内细菌刺激实验结果显示无乳链球菌(Streptococcus agalactiae)可激活Pm Toll9在肝胰腺、肠、淋巴和鳃中的表达,哈维氏弧菌(Vibrio harveyi)可显著抑制Pm Toll9在肝胰腺中的表达。提示无乳链球菌可通过Pm Toll9激活Toll信号通路,引起机体免疫防御反应,而哈维氏弧菌对此过程具有一定的抑制作用。     

施氮对蜀恢498及其突变体株型和物质生产特性的影响

【目的】分析不同施氮量处理下水稻株型、物质生产以及产量的变化规律,为水稻新品种的选育和栽培管理提供参考。【方法】2015-2016年,以蜀恢498(R498)及其突变体sg1和sg2为材料,采用两因素裂区设计,其中施氮量为主因素(0,90,180 kg/hm~2以下简称为CK,N90,N180),水稻材料为副因素,分析了不同施氮处理下蜀恢498及其突变体节间长度、叶部特征、叶面积指数、高效叶面积率、粒叶比、干物质量、产量及其构成因素的变化。【结果】(1)施氮对R498及其突变体sg1和sg2上部N_1～N_5节间长度均有一定影响,其中N_1、N_2和N_3的节间长度均表现为R498sg1sg2,差异达到显著水平,N_4和N_5节间长度无明显变化规律。在同一节间下,低氮处理(N90)的节间长度与高氮处理(N180)的差异不显著。与CK相比,施氮增加了水稻叶片长度和宽度、单叶面积以及叶面积指数,降低了2016年高效叶面积率。(2)随着施氮量的增加,粒叶比呈降低趋势;3个材料中,sg1的粒叶比最大,比R498和sg2分别高14.97%和34.83%。(3)干物质量随施氮量的增加而增大,N90与N180处理间差异较小。2015-2016年,水稻的产量均表现为R498sg1sg2。R498、sg1和sg2产量均随施氮量的增加而增大。2015和2016年,R498、sg1和sg2 N90处理的产量比N180处理分别减少了14.96%,14.45%,23.77%和2.23%,6.25%,8.66%。有效穗数和千粒质量均表现为R498sg1sg2,而颖花数和着粒密度则表现为sg2sg1R498;施氮对有效穗数影响最大,N90与N180处理间差异总体达到显著水平。(4)2015和2016年,N90处理氮肥偏生产力处理显著高于N180处理。氮肥农学利用率表现为sg2sg1R498,氮肥偏生产力表现为R498sg1sg2。【结论】突变体sg1对氮响应较慢,在水稻育种中有很大的应用价值。在杂交品种选育中,可通过观测不同材料在不同供氮水平下的表现,从而选育出稳产增产的水稻新品种,更好地实现减氮稳产增效。     

不同剂量25羟基维生素D3对断奶前犊牛血液生化指标、抗氧化能力和免疫功能的影响

为研究不同剂量25羟基维生素D₃[25(OH)VD₃]对断奶前犊牛血液水平、抗氧化能力和免疫功能的影响,选取18 头健康状况良好的新生荷斯坦犊牛,随机分成3 组,每组6 头进行为期56 天的饲养试验。分为对照组[不添加25(OH)VD₃]、低剂量组[25(OH)VD₃添加量6 000 IU/头·天]和高剂量组[25(OH)VD₃添加量12 000 IU/头·天]。结果表明,与对照组相比,随着25(OH)VD₃添加剂量增加,血浆生长激素、胰岛素样生长因子-1、过氧化氢酶、超氧化物歧化酶、总抗氧化能力以及免疫球蛋白G(IgG)含量显著增加(P<0.05),而丙二醛含量随剂量增加而存在降低趋势(P=0.079)。与对照组和低剂量组相比,高剂量组血浆免疫球蛋白A(IgA)含量有增加趋势(P=0.059)。综上所述,断奶前犊牛饲喂高剂量25(OH)VD₃有利于促进体内生长激素和胰岛素样生长因子-1分泌,可提高犊牛抗氧化能力,增强免疫功能。     

Effect of dietary carbohydrate levels on growth performance,non‐specific immune enzymes and acute response to low salinity and high temperature of juvenile sea cucumber Apostichopus japonicus

This study was performed to determine the optimum dietary carbohydrate (CHO) levels of sea cucumber, based on the parameters of growth, digestive enzymes, digestibility, non‐specific immune enzymes and acute low‐salinity (20 g/L) stress and high‐temperature (30°C) stress tolerance. Diets with eight different CHO (dextrin) levels (32.9, 107.6, 192.5, 257.2, 316.8, 428.0, 482.4 and 572.8 g/kg) were fed to sea cucumber juveniles (0.49 ± 0.01 g) for 60 days. Significant higher amylase activity was observed in sea cucumbers fed diet with CHO ranging between 32.9 and 192.5 g/kg than that of other treatments (p < .05). The sea cucumbers fed with 192.5 g/kg CHO showed significantly higher acid phosphatase activity than the treatments of 482.4 and 572.8 g/kg CHO (p < .05), and significantly higher alkaline phosphatase activity than other treatments (p < .05, except 257.2 g/kg). The treatments of 428.0–572.8 g/kg were found significantly lower values than other treatments in apparent digestibility coefficients for dry matter and crude protein (p < .05). The sea cucumbers fed with 192.5, 257.2 and 316.8 g/kg CHO showed better tolerance to high‐temperature (30°C) and low‐salinity (20 g/L) stress than other treatments. In brief, the optimal dietary CHO level for the growth of juvenile sea cucumber is 177.96 g/kg. However, excessive CHO will inhibit amylase enzyme activity and decrease digestibility, resulting in low growth of sea cucumber.     

Effects of dietary starch levels on the growth,plasma metabolites and expression of genes involved in glucose transport and metabolism in Pelodiscus sinensis juveniles

A 10‐week feeding trial was conducted to evaluate the growth performance, glucose transport and metabolism of Chinese soft‐shelled turtles (Pelodiscus sinensis) exposure to graded levels of dietary starch (0.52%, 7.43%, 14.74%, 22.99% and 31.38%). The 360 turtles (initial body weight, 12.94 ± 0.50 g) with 12 replicates were randomly assigned to five experimental diets. The highest weight gain and specific growth rate (SGR) were observed in 7.43% group and the lowest in 31.38% group. The protein efficiency ratio, whole‐body lipid contents, hepatic glycogen contents and the 4‐hr postprandial plasma glucose levels were significantly increased with the increment of starch levels (p < .05). In contrast, the daily feed intake and feed conversion ration were significantly declined (p < .05). The mRNA levels of glucose transporter 2, glucokinase, pyruvate kinase, malic enzyme and acetyl‐CoA carboxylase alpha genes in the liver significantly increased as the increase in starch levels at 4‐hr and 24‐hr post feeding (p < .05). No significant differences were observed in the expression of gluconeogenesis genes at each time point (p > .05). These results suggested that dietary addition of starch up‐regulated hepatic glycolysis, glycogenesis and lipogenesis genes expression, but the deficient response of gluconeogenesis to dietary starch might be part of the causes limited the starch utilization. Based on the secondary polynomial regression of SGR, y = ?0.0011x² + 0.028x + 1.63 (R² = 0.9292), the 12.73% inclusion level of dietary starch was recommended in juvenile turtles.     

植物免疫诱抗剂的作用机理和应用研究进展

植物免疫诱抗剂除了能诱导植物免疫反应以使植物获得或提高对病菌的抗性外,也可以激发植物体内代谢调控过程,促进植物生长,增加作物产量。植物免疫诱抗剂可以诱导植物产生系统获得抗性以使植物对病原菌产生广泛、长期的抗性。本综述全面、系统地介绍了植物免疫诱抗剂的种类及其目前在生产、病害防治上的应用状况,阐述了其作用机理,并展望了植物免疫诱抗剂的应用前景。通过对植物免疫诱抗剂发展历史和应用现状的分析,旨在为植物免疫诱抗剂未来的开发和应用提供一定的理论和实践依据。