混配制剂中拮抗细菌菌株Pf7-14在稻株上的群体数量及其对水稻纹枯病的防治

菌株Pseudomonas fluoresecens 7-14(pf7-14)显著地抑制了水稻纹枯病.在温室条件下,在水稻(品种为IR72)健株和纹枯病菌(Rhizoctonia solani)接种的病株上于分蘖盛期分别喷雾Pf7-14、混剂(Pf7-14+井冈霉素),菌株Pf-14对用于标记的抗生索萘啶酮酸(Nalidixic acid)具有天然的抗性,以上两处理中Pf7-14的浓度相同,约为2.2×108 cfu/mL,应用稀释平板法,在喷雾后的不同时期,在含萘啶酮酸100μg/mL的培养基上回收Pf7-14.结果表明:无论是在健株还是在病株上,在两批试验中.混剂中Pf7-14的种群数量总是高于其在单剂的数量,在健株上,应用1～4 d,两者显著性相差1.69～2.96倍(P=0.05).在病株上,第4～7 d,两者显著性相差1.74～3.70倍.田间试验结果表明,无论是一次防治,还是两次防治,与两个单剂相比,混剂(Pf7-14+井冈霉素)对水稻纹枯病的防治效果得到显著性提高.两次防治中,混剂的防治效果为83.46%,而单剂Pf7-14和井冈霉素的防治效果分别为56.92%和73.72%.     

24个甘蔗组合早代重演力和预测力分析

为研究甘蔗遗传特点和育种潜力,对常用的29个甘蔗亲本24个组合的7个性状进行重演力测试并进行相关分析和回归分析。结果表明,相关系数(r)和回归系数(b)都达到显著水平的性状有茎径、有效茎、锤度和单茎重,说明这些性状受环境影响较小,在甘蔗育种早期世代根据这一结果制订相应的选择标准,增大选择压力,可提高甘蔗育种效率。29个亲本中表现较好的亲本是ROC24、粤糖91-976、ROC1、ROC22,24个组合中综合性状较好的是ROC24×粤糖91-976、ROC1×ROC22、粤糖89-113×ROC22,在今后育种计划中可广泛利用。     

cDNA Cloning of Goat DNA Methyltransferase 1,Screening of shRNA Vectors and Influences to Development of Nuclear Transfer Embryos

This study was designed to clone cDNA of goat DNA methyltransferase 1（DNMT1） gene,to screen an effective shRNAproducing vector targeting goat DNA methyltransferase 1 and to improve the developmental competence of goat nuclear transfer embryos by decreasing the DNMT1 expression in donor cells.In this study,PCR primers were designed against regions of high homology between bovine and sheep sequences and then used to amplify the larger portions of the coding regions.Next,3 RNAi oligonucleotides were designed based on the cloned sequences and inserted into pRNAT-U6.1/Neo vector,acquiring 3 new vectors,respectively termed pRNAD1,pRNAD2 and pRNAD3.Then the positive cells were sorted by flow cytometry after transfection and detected by real-time PCR analysis and sodium bisulfite genomic sequencing.Finally,the developmental rates of nuclear transfer（NT） embryos generated using donor cells with and without the effective shRNA vector respectively,as well as in vitro fertilization（IVF） embryos were observed and recorded.The results showed that the coding regions of goat DNA methyltransferase 1 gene was successfully cloned（GenBank no.FJ617538）.Furthermore,an effective interfering shRNA（pRNAD2） was obtained,with its interference effect being 47.88%.Finally,NT embryos with shRNA vector harbored better developmental competence during morula and blastocyst stage compared to controls（P 〈 0.05）,reaching the similar rates to IVF embryos（P 〉 0.05）.In conclusion,goat DNA methyltransferase 1 gene cDNA was cloned and sequenced,an effective shRNA vector responsible for inhibiting DNA methyltransferase 1 expression was developed and the developmental competence of goat nuclear transfer morulae and blastcysts was significantly improved,which provided a feasible pathway for improving goat nuclear transfer embryo development competence by decreasing the methylation level in donor cells through RNAi-mediated manner.     

茂兰喀斯特森林大型土壤动物群落多样性初探

2008年7月至9月,对茂兰喀斯特森林3种植被类型下的大型土壤动物进行研究,共获5 728只,隶属3门7纲23类.选用类群数、个体数及多样性、均匀性、优势度指标来分析土壤动物群落结构.结果表明:茂兰喀斯特森林生态系统中,优势类群为膜翅目(蚁科)和蜘蛛目2类,稀有类群为原尾目、石蛃目、等翅目、同翅目、半翅目、双翅目(包含幼虫)、缨翅目、综合纲8类;两个优势类群的个体数占总捕获量的50.93%,3种植被类型的优势度:乔木林大于乔灌混交林大于草坡;均匀性指数差异不大;群落相似性系数差异较小.     

施氮量对甘蔗氮素吸收与利用的影响

在土壤低氮(碱解氮68.85 mg/kg)条件下,以新台糖22号(ROC22)为试材,分别施用15N标记的尿素2.5、5.0、7.5 g/盆,研究了氮肥施用量对甘蔗氮素吸收与利用的影响。结果表明,随着氮肥施用量的增加,甘蔗干物质积累、氮素积累、来源于肥料氮素的比率及土壤有效氮含量不同程度增加,但甘蔗氮肥利用率显著下降;施氮量明显影响甘蔗各器官的干物质分配、氮素分配、氮肥利用率及氮素在不同土层的分布;甘蔗主要吸收20~40 cm土层的氮素。甘蔗施用氮肥应考虑适宜的量和土层深度。     

酒石酸协同下TiO2光催化降解水溶性染料孔雀石绿的研究

研究了酒石酸协同下TiO2光催化降解水溶性染料孔雀石绿的影响因素、降解反应动力学以及作用机制.结果表明:酒石酸对TiO2降解孔雀石绿有明显的协同作用,相同试验条件下,3种不同光源对孔雀石绿的降解效果大小依次为:紫外光、模拟日光、可见光.孔雀石绿的光催化降解反应呈一级反应动力学特征.用苯作为羟基自由基(·OH)捕集剂,通过高效液相色谱仪(HPLC)检测苯酚,间接地测定了反应中间产物·OH.     

干扰对红鳞蒲桃群落植物多样性及重要值的影响

采用典型样方法对广西滨海红鳞蒲桃(Syzygium hancei)植物群落的物种丰富度指数(S),Shannon-Wiener指数(H′),Simpson指数(D),Pielou均匀度指数(Jsw)和重要值进行了调查分析.结果表明:在3块样地中,红鳞蒲桃群落共有植物物种98种,隶属于42科80属.样地间乔木层、灌木层和草本层的多样性均无明显差异.从不同层次的变异系数看,H′,D和Jsw均从大到小依次表现为灌木层、乔木层、草本层.红鳞葡桃在轻度、中度和重度干扰程度下的重要值分别为204.83%,77.71%和114.58%.由灌木的重要值分析显示,干扰程度越大,大于10%的种类就越多,其中重要值最高的种出现在中度干扰的G2.红鳞蒲桃群落具有较强的抗逆性,适度的干扰能促进群落的演替和更新.     

猪IGF-I基因SNP位点与生长性能的相关分析

【目的】分析猪胰岛素样生长因子I（IGF-I）基因SNP位点与生长性能的相关性,为后期猪的品种选育提供理论依据。【方法】采用PCR-RFLP对长白猪、环江香猪、广西巴马小型猪及长×巴F1代、F2代杂交猪的IGF-I基因SNP位点（rs322131043）进行分型,统计不同猪种该位点的基因型频率和等位基因频率,并分析长×巴F2代杂交猪的基因型频率与其生长性能的相关性。【结果】IGF-I基因SNP位点在广西巴马小型猪中以AA型为优势基因型,长白猪中以GG为优势基因型,其中A基因频率在广西巴马小型猪、环江香猪、长白猪3个品种中依次降低。不同基因型的长×巴F2代杂交猪中,基因杂合（AG）型猪的体重、体长、胸围、体高平均值在各日龄基本上都比基因纯合（AA/GG）型的低。【结论】猪IGF-I基因SNP位点与其生长性能密切相关,但该位点是否可应用于品种选育仍需进一步验证。     

猪肺血管紧张素转化酶的提取与纯化

[目的]研究猪肺血管紧张素转化酶（ACE）的提纯方法,为其生产利用提供技术支撑.[方法]以新鲜猪肺组织为试验材料,匀浆离心后经硫酸铵分级沉淀透析,然后采用离子交换-超滤离心联合法对猪肺ACE粗提物进行纯化,测定ACE的分子量、酶活力、纯化倍数及酶活力回收率.[结果]通过离子交换-超滤离心联合法分离纯化猪肺ACE,可得到相对分子量182 kDa、酶比活力1.2476 U/mg的电泳级纯品ACE,其纯化倍数达357.31倍,酶活力回收率达12.28％.ACE催化反应动力学米氏常数（Km）为0.849 mmol/L,最大反应速率（Vmax）为9.775 nmol/min.[结论]采用离子交换-超滤离心联合法纯化猪肺ACE能够极大缩短分离与纯化时间,且获得较高的纯化倍数和酶活力回收率,是猪肺ACE的高效纯化方法.     

A FIASCO-Based Approach for Detection and Diagnosis of Puccinia graminis f. sp. tritici in China

Stem or black rust of wheat, caused by the fungus Puccinia graminis Pers. f. sp. tritici Eriks.＆E. Henn. （Pgt）, has historically caused severe losses to wheat （Triticum aestivum L.） production worldwide. In the Fujian and Guangdong provinces of China, six moderate-to-severe epidemics of wheat stem rust have occurred, which caused destructive losses of wheat between 1949 and 1966, although these were brought under control by integrated management. A rapid and reliable detection of the pathogen will contribute to the accurate forecast and seasonal control of this disease. The objective of this study was to develop a diagnostic molecular marker generated from simple sequence repeats （SSR） for the early rapid identiifcation of P. graminis. The genomic DNA of P. graminis, Puccinia striiformis, Puccinia triticina and seven other species was ampliifed by a pair of SSR primers generated by the FIASCO （fast isolation by AFLP sequences containing repeats） enrichment protocol. The primer set Pgtw （f）/Pgtw （r） generated a polymorphic pattern displaying a 330-bp DNA fragment speciifc for P. graminis whereas no DNA fragment was obtained from other non-target wheat fungal pathogens. The detection limit of the primer was 1 ng DNA in a 25-mL PCR reaction. The SSR markers of P. graminis can also be used to detect the presence of latent hyphae in Pgt-infected wheat leaves as early as 30 h post-inoculation. A rapid approach to distinguish P. graminis from similar pathogenic fungi would be anticipated in further study.