口蹄疫病毒VP1基因密码子偏好性分析

VP1蛋白是口蹄疫病毒(FMDV)的主要结构蛋白,可诱导机体产生中和抗体以及激发保护性免疫应答。为探究VP1基因密码子偏好性,筛选出其最佳体外表达系统,使用Visual Gene Developer、CodonW、GraphPad Prism等软件,对VP1基因进行密码子偏好性分析,同时将VP1基因密码子使用频率与大肠杆菌、毕赤酵母、昆虫杆状病毒和哺乳动物细胞表达系统作了比较。结果显示,VP1基因的CAI为0.21,ENC为55.43,GC3S为65.26%,表明该基因密码子使用偏好较弱并且密码子偏好以G/C碱基结尾。结合VP1基因与各表达系统密码子使用频率比值,发现其与昆虫杆状病毒表达系统频率比值差异最小且CAI最大,因此推断昆虫杆状病毒表达系统是FMDV VP1基因最适体外表达系统。本研究为FMDV亚单位疫苗研制等提供了技术基础。     

宁夏雨养区不同青贮玉米品种生产性能及营养价值综合评价

为筛选适宜宁夏雨养区种植的青贮玉米品种,试验采用随机区组设计,对引进的8个青贮玉米品种农艺性状和营养成分进行综合评价.结果表明:8个青贮玉米品种间的株高、穗位高、茎粗、叶片数、鲜草产量、干物质、粗灰分、粗蛋白、粗脂肪以及淀粉含量均差异显著(P<0.05).中玉335及宁单34的生物学产量较高,且茎秆较为粗壮.中玉335、正大12及宁单34的干物质含量适中,粗蛋白、粗脂肪以及淀粉含量较高且中性洗涤纤维和酸性洗涤纤维含量较低,品质较好.对农艺性状和营养成分进行综合评价,中玉335和宁单34表现优良,适宜在当地推广种植.     

Betaine Alleviates Heat Stress-Induced Hepatic and Mitochondrial Oxidative Damage in Broilers

The aim of this study was to evaluate the effects of dietary betaine (BET) on growth performance, redox state, and related gene expression in broilers under heat stress (HS). A total of 144 21-day-old male broiler chickens with similar body weights were assigned randomly to three treatments with six replicates (eight chickens per replicate cage). Broilers in the control (CON) group were kept at thermoneutral (TN, 22±1°C) conditions and fed a basal diet until they were 42 days of age. Broilers in the other two groups (defined as HS and HS + BET) were exposed to HS (34±1°C, 8 h/day) and fed the basal diet without or with 1000 mg/kg BET, respectively. Rectal and cockscomb temperature of broilers was increased (P<0.05) in HS and HS + BET groups compared with the CON group, whereas there was no difference between HS and HS + BET groups. Dietary BET supplementation restored (P<0.05) average daily gain (ADG) and average daily feed intake (ADFI) of broilers and reversed (P<0.05) the increase in serum alanine transaminase (ALT) activity and malondialdehyde (MDA) content in the liver tissue of broilers under HS. The HS + BET group had higher (P<0.05) activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) in the liver tissue and mitochondria than the HS group, and the same pattern was observed for glutathione (GSH) and GSH/glutathione disulphide (GSSG) in the liver tissue. The decreased mRNA levels of GPX1 and uncoupling protein (UCP) in the liver induced by HS were restored by BET supplementation. In conclusion, dietary BET supplementation can alleviate HS-induced hepatic and mitochondrial oxidative damage of broilers by regulating mRNA expressions of GPX1 and UCP.     

餐厨废弃物饲料化技术及其在动物生产中的应用

餐厨废弃物(food waste,FW)的资源利用受到广泛关注。FW焚化、填埋、堆肥、厌氧消化等技术因其面临的环境可持续性问题而受到越来越多的批评。饲料化技术可以将FW转化为高价值的饲料,从而减少固体废物的排放、养殖成本和环境污染,但该技术应符合减少、再利用和回收有机废物的处理原则。作者综述了FW的饲料化技术及其在动物生产中的应用。FW饲料化技术主要包括热处理、酶处理、藻类培养、昆虫过腹、发酵技术。其中热处理可以确保微生物安全性,是其他技术的预处理技术。藻类培养和昆虫过腹技术可以将FW转化为植物和昆虫蛋白,避免同源污染,但尚不清楚藻类和昆虫在FW利用过程中是否会造成污染物积累。酶处理和发酵技术可以将FW中大分子转化为小分子。酶的催化性能和稳定性容易受外界条件的影响,需要考虑特殊的酶制剂。发酵技术的机械化程度和资源利用率高,其核心是微生物,需要筛选有效的、能充分利用FW的微生物。目前FW在畜牧业中的应用较少,在其生产和应用中要特别注意用量和使用时间。为了使FW饲料真正作为动物饲料进入食物链,研究人员必须对不同动物(含不同生长阶段)的生长性能和产品特性进行研究,以确保动物健康及动物产品对人类健康没有负面影响。     

基于SPCE061A的车载灯光语音识别系统设计

在介绍车载灯光非特定人语音识别系统的组成和原理的基础上,重点分析了基于隐马尔可夫模型(HMM)的模板训练和语音识别算法。选用凌阳SPCE061A的16位单片机进行了系统的硬件和软件设计。制定了本语音识别系统的实验方案,实验结果基本满足灯光控制的要求。     

4LMZ160型履带式苎麻联合收割机的研究

分析了我国苎麻联合收割机现状及存在的问题,设计了适合我国苎麻主产区收获作业的履带式苎麻联合收割机,并对样机的关键部件进行了详细说明。该机一次可完成割幅160mm收割,整机转弯半径小,操作方便,对麻地高垄有较好适应性。其整机结构配置新颖独特,使用半喂入稻麦联合收获机底盘,采用全液压传动技术直接驱动苎麻收割机行走和机具作业,可一次性完成切割、输送、收集功能。田间性能测试结果表明:该机漏割率、割茬高度、作业小时生产率等各项性能指标均到达设计要求。     

Pyruvate kinase is necessary for Brucella abortus full virulence in BALB/c mouse

Brucellosis, caused by a facultative intracellular pathogen Brucella, is one of the most prevalent zoonosis worldwide. Host infection relies on several uncanonical virulence factors. A recent research hotpot is the links between carbon metabolism and bacterial virulence. In this study, we found that a carbon metabolism-related pyruvate kinase (Pyk) encoded by pyk gene (locus tag BAB_RS24320) was associated with Brucella virulence. Determination of bacterial growth curves and resistance to environmental stress factors showed that Pyk plays an important role in B. abortus growth, especially under the conditions of nutrition deprivation, and resistance to oxidative stress. Additionally, cell infection assay showed that Pyk is necessary for B. abortus survival and evading fusion with lysosomes within RAW264.7 cells. Moreover, animal experiments exhibited that the Pyk deletion significantly reduced B. abortus virulence in a mouse infection model. Our results elucidated the role of the Pyk in B. abortus virulence and provided information for further investigation of Brucella virulence associated carbon metabolism.     

干旱及盐胁迫对酸浆种子萌发特性的影响

以酸浆种子为试材,分别采用浓度为0%~25.0%的PEG-6000模拟干旱胁迫,同时用0~150mmol·L~(-1) NaCl溶液模拟盐分胁迫,分别考察酸浆种子的抗旱和抗盐萌发特性。结果表明:随着PEG浓度增加,酸浆种子萌发延迟,且发芽率、发芽势和发芽指数均呈现明显下降趋势,PEG达25.0%时,酸浆种子没有萌发;临界胁迫浓度C_(50)为12.3%,高于番茄种子C50(8.0%~10.8%)。随着NaCl溶液浓度升高,酸浆种子的发芽率、发芽势、发芽指数也呈下降趋势;浓度达到150mmol·L~(-1)时,种子发芽率比对照组降低43.0%,萌发种子不能发育为正常幼苗;其C50为107.0mmol·L~(-1),低于向日葵种子的C_(50)(258.0mmol·L~(-1))。     

营造农业科技创新环境推进高效农业规模化建设——沛县农业科技创新工作现状及对策

本文通过对沛县农业科技创新的现状的分析,针对农业科技创新工作中存在的问题,提出了"十一五"期间农业科技创新的发展对策,来推进该县的高效农业规模化建设.     

美国军事司法禁止强制性自证其罪规则解读

美国军事司法禁止强制性自证其罪规则,与"米兰达规则"有着本质区别。尽管二者在法源上相同,但建立的规则不同。美国军事司法禁止强制性自证其罪规则确立了禁止刑讯逼供原则、预先告知原则和非法证据排除规则,但虐囚事件充分暴露了美国军事司法禁止强制性自证其罪规则的本质。