Regulation of mitogen-activated protein kinase 3/1 activity during meiosis resumption in mammals

In vivo, resumption of oocyte meiosis occurs in large ovarian follicles after the preovulatory surge of luteinizing hormone (LH). The LH surge leads to the activation of a broad signaling network in mural granulosa cells equipped with LH receptors. The signals generated in the mural granulosa cells are further augmented by locally produced peptides or steroids and transferred to the cumulus cell compartment and the oocyte itself. Over the last decade, essential progress has been made in the identification of molecular events associated with the final maturation and ovulation of mammalian oocytes. All new evidence argues for a multiple roles of mitogen-activated protein kinase 3/1 (MAPK3/1) in the gonadotropin-induced ovulation processes. However, the knowledge of gonadotropin-induced signaling pathways leading to MAPK3/1 activation in follicular cells seems limited. To date, only the LH-induced transactivation of the epidermal growth factor receptor/MAPK3/1 pathway has been described in granulosa/cumulus cells even though other mechanisms of MAPK3/1 activation have been detected in other types of cells. In this review, we aimed to summarize recent advances in the elucidation of gonadotropin-induced mechanisms leading to the activation of MAPK3/1 in preovulatory follicles and cultured cumulus-oocyte complexes and to point out a specific role of this kinase in the processes accompanying final maturation of the mammalian oocyte.     

Cross-resistance profile of mesosulfuron-methyl-resistant Italian ryegrass in the southern United States

Diclofop-resistant Lolium species (ryegrass) is a major weed problem in wheat production worldwide. This study was conducted to determine the resistance pattern of diclofop-resistant ryegrass accessions from the southern United States to mesosulfuron-methyl, a recently commercialized herbicide for ryegrass control in wheat; to determine the cross-resistance pattern of a Lolium multiflorum Lam. (Italian ryegrass) accession, 03-1, to acetolactate synthase (ALS) and acetyl-CoA carboxylase (ACCase) inhibitors; and to determine the resistance mechanism of Italian ryegrass to mesosulfuron-methyl. Seventeen ryegrass accessions from Arkansas and Louisiana, including standard resistant and susceptible accessions, were used in this experiment. Fourteen of the 17 accessions were more resistant (four- to > 308-fold) to diclofop than the standard susceptible biotype. One accession, 03-1, was resistant to mesosulfuron-methyl as well as to other ALS inhibitor herbicides such as chlorsulfuron, imazamox and sulfometuron. Accession 03-1, however, did not show multiple resistance to the ACCase inhibitor herbicides diclofop, fluazifop, clethodim, sethoxydim and pinoxaden, nor to glyphosate. The in vivo ALS activity of the 03-1 biotype was less affected by mesosulfuron-methyl than the susceptible biotype. This indicates that the resistance mechanism of Italian ryegrass to mesosulfuron-methyl is partly due to an alteration in the target enzyme, ALS. It is concluded that diclofop-resistant ryegrass in the southern United States can be generally controlled by mesosulfuron-methyl. However, mesosulfuron-methyl must be used with caution because not all ryegrass populations are susceptible to it. There is a need for more thorough profiling of ryegrass resistance to herbicides.     

昆虫几丁质合成关键酶功能及其RNAi技术在害虫防治中的研究进展

几丁质对昆虫的生长发育至关重要,且不存在于植物和哺乳动物中,因此其合成途径的关键酶是较为理想的杀虫剂靶标。近年来,多种害虫的几丁质合成关键酶基因被克隆和鉴定,通过RNAi技术应用于一些重要害虫的防治研究工作中。本文较为系统的总结了近些年害虫几丁质合成关键酶的基因克隆及功能研究进展,重点阐述了几丁质合成酶、海藻糖酶基因基于RNAi技术应用于害虫防治取得的研究进展,分析了RNAi技术通过转基因植物表达dsRNA（RNAi抗虫作物）以及作为核酸农药（dsRNA）直接进行作物喷施的两种应用途径,文章最后还探讨了RNAi在害虫防治中面临的主要瓶颈问题以及主要应对策略。上述较为系统的归纳和总结,目的是为今后基于几丁质合成关键酶的RNAi技术应用于害虫绿色防控研究提供有价值的理论指导。     

中国野生毛葡萄芪合酶基因表达及对葡萄抗白粉病的影响

【目的】克隆中国野生毛葡萄（Vitis quinquangularis）‘丹凤-2’芪合酶（stilbene synthase）基因（STS）并研究其功能,为提高欧洲葡萄（V. vinifera）的白粉病抗性及品质提供依据。【方法】利用同源克隆法获得中国野生毛葡萄‘丹凤-2’芪合酶基因VqSTS9和VqSTS21,构建植物过表达载体;用无核白单芽茎段诱导出分生愈伤组织,作为农杆菌介导法遗传转化的受体材料,获得抗性植株,经过不同水平检测,确定转基因植株;对野生型和转基因植株叶片人工接种葡萄白粉病菌（Uncinula necator）,通过显微技术观察叶片受白粉病菌侵染后的情况,比较两者对白粉病的抗性;利用实时荧光定量PCR（qRT-PCR）分析野生型和转基因植株在自然条件和接种白粉病菌后STS及其相关基因的表达,用高效液相色谱法（HPLC）检测转基因植株中芪类物质的种类与含量。【结果】同源序列克隆得到VqSTS9（JQ868689）与VqSTS21（JQ868677）的cDNA序列,长度为1 179 bp。经PCR和Western blot检测,鉴定出过表达VqSTS9无核白植株4株和过表达VqSTS21无核白植株3株。显微观察发现,与野生型植株相比,转VqSTS9 和VqSTS21植株叶片上的菌丝生长较慢,表现出对白粉病的抗性。qRT-PCR结果表明,自然生长条件下,与野生型植株相比,转VqSTS9和VqSTS21植株STS的表达量提高,STS上游苯丙氨酸裂解酶基因（PAL）、下游白藜芦醇糖基转移酶基因（RSGT）、转录因子基因（MYB14、MYB15）的表达量均不同程度上升,而查尔酮合成酶基因（CHS）表达量降低;人工接种白粉病菌后,与野生型植株相比,转基因植株STS表达量显著上调。高效液相色谱分析表明,自然条件下,芪类物质主要以反式云杉新苷形式存在,转基因植株芪类物质的含量高于野生型植株;在接种白粉病菌诱导表达后,除了反式云杉新苷,还产生了反式白藜芦醇和葡萄素,即转基因植株体内芪类物质的种类和含量均有所增加。【结论】将VqSTS9、VqSTS21转入无核白后,转基因植株STS的表达量增高,芪类物质的含量与种类增加,并抑制白粉病菌的生长。因此,中国野生毛葡萄‘丹凤-2’携带的VqSTS9和VqSTS21能够增强欧洲葡萄对白粉病的抗性,‘丹凤-2’可用作葡萄抗病性育种的种质资源。     

海鲈游泳续航时间和运动代谢规律研究

为研究海鲈(Lateolabrax japonicus)的游泳续航能力和游泳过程中的物质代谢规律,以深水网箱养殖的3月龄海鲈为研究对象,采用游泳续航时间和生化指标作为评测海鲈游泳能力和代谢规律的方法进行了试验。结果显示,海鲈的游泳续航时长为200 min,其续航能力强于大黄鱼而弱于美国红鱼。在游泳过程中,海鲈血糖浓度升高,但差异性不显著(P＞0.05),肌糖原随着时间的增加显著减少(P＜0.05),且肌糖原浓度在海鲈疲劳时接近于0。当鱼接近100%疲劳时,其肝糖原浓度也接近于0;当海鲈以不同疲劳程度游泳时,其肌肉乳酸脱氢酶浓度会显著升高(P＜0.05)。表明海鲈的续航游泳过程伴随着无氧呼吸和有氧呼吸。     

多花水仙HMGS基因的克隆

以多花水仙花瓣抑制消减杂交文库获得的羟甲基戊二酰辅酶A合酶（HMGS）基因片段为基础,采用cDNA末端快速扩增（RACE）技术从黄花水仙2号和金盏银台中各克隆一条HMGS基因,两基因均含有一个1413bp的开放阅读框,编码470个氨基酸,但存在2个氨基酸差异．氨基酸序列分析表明：黄花水仙2号与葡萄、大豆、蓖麻和玉米HMGS基因的氨基酸相似系数分别为83％、82％、82％和81％．以水仙Actin基因为内参基因,采用荧光定量PCR方法分析HMGS基因在两品种的表达水平,结果表明：两品种HMGS基因的表达水平差异并不明显．     

栉孔扇贝神经节一氧化氮合酶的组织化学和免疫组化定位

采用组织化学和免疫组化技术对栉孔扇贝(Chlamys farreri)神经节内的一氧化氮合酶(NOS)进行定位研究。组织化学显示,存在NOS的部位如下：脑神经节内纵行的神经纤维和表层的少量小细胞;足神经节表层的大量小细胞,中央大量水平分布的神经纤维;脏神经节中部大量水平分布的神经纤维,前叶内大量小细胞和神经纤维,后叶内少量小细胞和许多环行神经纤维,侧叶内大量似放射状分布的神经纤维;脑足和脑脏神经索内的神经纤维。免疫组化定位表明,神经型一氧化氮合酶(nNOS)和诱导型一氧化氮合酶(iNOS)在整个神经系统内均呈阴性;足神经节和脏神经节内有少量神经细胞呈内皮型一氧化氮合酶(eNOS)强阳性;各神经节和神经索内的部分小细胞和神经纤维呈eNOS弱阳性。栉孔扇贝进化上为较低等的贝类,NOS阳性神经细胞应主要分布于外周器官组织内。神经系统内大量的NOS可在其神经传导和免疫调节等方面发挥重要的作用。     

Blood chemistry and organ nutrient composition in Atlantic salmon, Salmo salar L., fed graded amounts of wheat starch

After feeding Atlantic salmon, Salmo salar L., five graded amounts of wheat starch from 0 to 310 g kg^?1, low but increased levels of glycogen in kidney, heart and gills were determined. No variations were found in proximate or glycogen compositions of muscle, whereas the liver composition reflected the diet composition. Whole-body homogenates varied in dry matter and lipid levels; the variation was according to g lipid eaten per fish. Plasma glucose levels ranged above average levels only when the starch level in the feed was higher than 220 g kg^?1. Although feed intake and thereby lipid intake increased as dietary carbohydrate increased in the present experiment, no differences in plasma concentrations of cholesterol and only small changes in triglycerides were determined. The increase in dietary carbohydrate was balanced with protein, and total plasma protein concentrations followed the decrease in feed protein content. Haematocrit, haemoglobin, mean cell volume and mean cell haemoglobin all showed significantly reduced levels as dietary starch increased, indicating a fibre effect from ‘left-over’ starch in the intestine followed by reduced absorption of divalent ions, such as iron.     

嗜酸小球菌对凡纳滨对虾体液免疫因子的影响

在饲料中添加不同剂量的嗜酸小球菌投喂凡纳滨对虾,并在投喂后的20、40和60d,分别测定凡纳滨对虾血清中的一氧化氮合酶(NOS)、溶菌活力(Bacteriolytic activity)、总超氧化物歧化酶(T-SOD)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP),并分析了这5种酶之间的相关性。结果显示,嗜酸小球菌能有效提高凡纳滨对虾体内的NOS、溶菌活力、T-SOD、ACP、AKP的活性;NOS与溶菌活力存在显著正相关性(P<0.05),与SOD存在显著负相关性,溶菌活力与AKP存在显著负相关性。表明在饲料中添加适量的嗜酸小球菌(剂量10mg/kg)可使凡纳滨对虾体液免疫因子活力到达较高的水平;凡纳滨对虾血清中一氧化氮合酶对于嗜酸小球菌的添加量较为敏感,可作为评价嗜酸小球菌使用效果的指标之一。