荧光显色在环介导等温扩增（LAMP）检测猪繁殖与呼吸综合征病毒的应用

介绍了一种应用荧光显色的猪繁殖与呼吸综合征病毒(Porcine reproductive and respiratory syndrome virus,PRRSV)反转录环介导等温扩增(RT-LAMP)的检测方法.该方法使用了针对靶序列M+N基因的一组引物,并且能在63 ℃等温条件下30 min内完成反应.在敏感性检测中RT-LAMP与RT-PCR都能检测103个包含靶基因片段的重组质粒.几种其它病原的核酸也被用来比较这两种方法的特异性,两种方法只能检测PRRSV.在荧光显色剂应用试验中,证实0.05 mmol/L钙黄绿素以及0.6 mmol/L锰离子可以用于LAMP扩增产物的判断,并且其判断结果与浊度判断结果一致.在对103个临床血液样本的检测中,RT-LAMP与RT-PCR检出的阳性样本数量分别是56个和48个.结果说明,应用荧光显色剂的RT-LAMP检测方法可以快速检测PRRSV.     

荔枝霜疫霉巢式PCR和LAMP检测方法的建立

由荔枝霜疫霉(Peronophythora litchii)引起的荔枝霜疫霉病是荔枝(Litchi chinensis)生产上的重要病害,建立霜疫霉快速准确检测方法,对于该病的早期诊断和及时防控至关重要.本研究以荔枝霜疫霉三磷酸鸟苷(GTP)结合蛋白基因(GTP-binding protein gene,Ypt1)为靶序列,设计特异性引物,建立了巢式PCR和环介导等温扩增(loop-mediated isothermal amplification,LAMP)两种检测方法,并进行特异性和灵敏度验证.特异性检测表明,只有不同来源的21个荔枝霜疫霉菌株经PCR扩增获得249 bp的特异性条带,同时,在钙黄绿素指示剂的作用下,LAMP检测显示绿色,且扩增产物用2.0％琼脂糖凝胶电泳出现特有的梯形条带,而其他13种不同卵菌近缘种及8种常见病原真菌42个菌株均未观察到这些现象.灵敏度检测显示,将特异引物PvYF1/PvYR1与疫霉属Yptl通用引物Yph1F/Yph2R进行巢式PCR扩增后,其检测灵敏度在DNA水平上可达100fg/25 μL,较常规PCR提高1 000倍,而LAMP方法检测灵敏度是巢式PCR的10倍.本研究分别采用常规PCR、巢式PCR和LAMP方法对采集自福建省荔枝霜疫霉病典型症状及可疑症状的荔枝叶片或果实进行检测,并用传统分离方法进行验证.结果表明,在漳州采集的30份样品中,常规PCR、巢式PCR和LAMP方法的阳性检出率分别为17/22(77.3％)、20/22(90.9％)和21/22(95.5％);在莆田采集的25份样品中,常规PCR、巢式PCR和LAMP方法的阳性检出率分别为15/17(88.2％)、16/17(94.1％)、17/17(100％).可见LAMP方法明显提高了检测效率,并且具有检测程序便捷,所需设备简单和肉眼能判断结果的优势,适合基层部门及田间荔枝霜疫霉快速检测.     

新发PDCoV和TGEV双重RT-PCR检测方法的建立及初步应用

猪Delta冠状病毒(Porcine deltacoronavirus,PDCoV)是一种新发现的冠状病毒,临床上主要引起感染仔猪出现水样腹泻、呕吐和脱水等症状,和猪传染性胃肠炎病毒(Porcine transmissible gastroenteritis virus,TGEV)感染引起的临床症状极为类似,且临床上PDCoV和TGEV混合感染时有发生,单靠临床诊断很难区分两种疾病,因此建立同时检测且区分PDCoV和TGEV的检测方法具有重要的临床意义.本研究根据GenBank中收录的PDCoVN基因和TGEVN基因序列设计了2对引物,在同一反应体系中同时扩增PDCoV的N基因片段和TGEV的N基因片段,通过对RT-PCR反应条件的优化,建立了同时检测PDCoV和TGEV的双重RT-PCR方法,并对该方法进行了特异性、灵敏性和重复性研究.结果显示,所建立的双重RT-PCR对PDCoV和TGEV的最低检测量分别是3.14×102 copies/μL和3.68× 103 copies/μL,利用该双重RT-PCR方法对猪流行性腹泻病毒(Porcine epidemic diarrhea virus,PEDV)、猪博卡病毒(Porcinebocavirus,PBoV)、猪繁殖与呼吸综合征病毒(Porcine respiratory and reproductive syndrome virus,PRRSV)和猪伪狂犬病毒(P.pseudorabiesvirus,PRV)的扩增结果均为阴性,显示出较好的特异性.为了解所建立的双重RT-PCR方法的临床应用效果,对252份临床样品进行了检测.结果表明,双重RT-PCR检出PDCoV阳性样品31份(阳性率为12.30％),TGEV阳性样品12份(阳性率为4.76％),同时感染PDCoV和TGEV的阳性样品2份(阳性率为0.79％),且检测结果与单一PDCoV和TGEV RT-PCR相符.因此,本研究所建立的双重RT-PCR方法可用于PDCoV和TGEV的临床检测,为进一步研究PDCoV和TGEV的临床鉴别诊断和流行病学调查提供了理论依据和技术支持.     

H9亚型禽流感病毒环介导等温扩增检测方法的建立与荧光指示剂的应用

利用反转录环介导等温核酸扩增技术(RT-LAMP),建立了一种特异、灵敏、便捷的H9亚型禽流感病毒(H9subtype of avian influenza virus,H9-AIV)的检测方法。该方法使用了对应于H9亚型禽流感病毒血凝素(hemagglutinin HA)基因的8个不同区域的6条特异引物,在63℃的等温条件下反应,最低可检测到103拷贝的目的基因重组质粒片段,较RT-PCR方法敏感10倍。通过对15种H亚型禽流感病毒、新城疫病毒(Newcastle disease virus,NDV)、传染性支气管炎病毒(Infectious bronchitis virus,IBV)的检测表明,该方法具有良好的特异性。在反应体系中使用钙黄绿素与Mn2+的混合溶液作为荧光指示剂可以用于RT-LAMP结果判定,并且其判断结果与浊度判断结果一致。对109份禽咽喉拭子及泄殖腔拭子临床样品进行检测,RT-LAMP与RT-PCR检出阳性样本数分别为61份和46份,表明RT-LAMP方法阳性检出率高于RT-PCR。     

牛支原体的环介导等温扩增快速检测技术研究

牛支原体(Mycoplasma bovis是感染牛的一种重要的致病性病原体.本研究利用环介导等温扩增(loop-mediated isothermal amplification,LAMP)技术建立了牛支原体的快速检测方法.该方法以牛支原体保守性基因uvrC为靶序列设计了5条特异引物,在58℃等温条件下,60 min即可完成反应.LAMP方法能检测出20 pg牛支原体DNA,较PCR方法高100倍,用牛鼻支原体(M.bovirhinis)、无乳支原体(M.agalactiae)、精氨酸支原体(M.ariginini)、牛副流感病毒(BPIV)、牛腺病毒(BADV)、牛传染性鼻气管炎病毒(IBRV)作特异性检测,两种方法均有很高的特异性.本研究还将荧光显色剂钙黄绿素(calcein)和Mn2+用于LAMP反应结果的可视化检测.临床鼻拭子样品煮沸后,可直接进行等温扩增,省去了DNA提取步骤.在对167个临床鼻拭子样本的检测中,LAMP方法检测结果阳性率(26.95％)高于PCR方法检测出阳性率(19.16％),这证明本研究所建立的方法,与PCR法比较更适于临床样品的检测.研究结果表明,LAMP方法具有操作简便、快速、高效、敏感、特异、经济等特点,适于基层实验室监测的广泛使用.     

利用环介导等温扩增技术快速检测水产品中的副溶血弧菌

副溶血弧菌(Vibrio parahaemolyticus)是一种重要的食源性致病菌。首次将环介导等温扩增技术（Loop-Mediated Isothermal Amplification, LAMP）应用于副溶血弧菌的快速检测。针对副溶血弧菌不耐热溶血毒素基因（tlh）设计四条特异性引物,建立了副溶血弧菌LAMP检测方法,1 h即可完成。对12种细菌共28株菌进行LAMP扩增,仅副溶血弧菌得到阳性结果,证明引物具有很高的特异性;副溶血弧菌基因组DNA和纯培养物的检测灵敏度分别为90 fg/LAMP反应体系和24 cfu/mL,对模拟食品样品进行直接检测,检测限为89 cfu/g;对40份水产样品进行检测,8份副溶血弧菌LAMP阳性,其中6份传统培养阳性。本研究表明,该方法检测副溶血弧菌特异性强、灵敏度高,并且操作简便、快捷、检测成本低,有望发展成为快速检测副溶血弧菌的有效手段。     

二温式多重PCR检测对虾的白斑综合征病毒和桃拉综合征病毒

根据多重PCR的技术原理,利用对虾(Penaeus vannamei)白斑综合征病毒和桃拉综合征病毒的基因序列分别设计了两对特异引物,并将常规三温式PCR扩增程序简化为2个温度梯度,建立二温式多重PCR技术用于对虾白斑综合征病毒(White spot syndrome virus,WSSV)和桃拉综合征病毒(Taura syndrome virus,TSV)的复合快速检测。利用二温式PCR能特异地扩增出WSSV和TSV的基因片段。结果表明,二温式多重PCR技术具有较高的特异性和敏感性,最低能检测到WSSV核酸模板10pg,TSV核酸模板100pg,且对其它一些对虾病原呈阴性。     

一种新型对虾白斑综合症病毒和桃拉综合症病毒复合快速检测技术-二温式多重PCR的建立

摘要：本研究建立了一种二温式多重PCR技术，用于对虾白斑综合症病毒（white spot syndrome virus ,WSSV）和桃拉综合症病毒(taura syndrome virus ,TSV)的复合检测。根据对虾白斑综合症病毒和桃拉综合症病毒的基因序列分别设计了两对特异引物F1 、R1和 F1、 R2，利用该PCR能特异扩增出WSSV和TSV基因片段，结果表明：二温式多重PCR技术具有较高的特异性和敏感性，最低能检测到WSSV核酸模板10pg,TSV核酸模板100pg，且对其它一些对虾病原呈现阴性。     

结合不对称PCR技术构建鸡NDV-IBV-ILTV联合检测基因芯片

基因芯片(gene chip)是依据核酸杂交原理发展的一种生物新技术,在生命科学研究领域具有重要的应用价值.本研究将不对称PCR和基因芯片两种技术相结合,构建了同步检测鸡(Gallus gallus)传染性喉气管炎病毒(Infectious laryngotracheitis virus,ILTV)、新城疫病毒(Newcastle disease virus,NDV)、传染性支气管炎病毒(Infectious bronchitis virus,IBV)的共检基因芯片.分别选取ILTV的胸苷激酶(thymidine kinase,TK)和糖蛋白B(glycoproteins B,gB)基因、NDV的融合蛋白(fusion,F)和血凝素-神经氨酸酶蛋白(haemagglutinin-neuraminidase,HN)基因以及IBV的膜蛋白(membrane,M)和核衣壳(nucleocapsid,N)基因设计引物,从重组质粒菌中扩增制备探针基因,用乙醇沉淀法纯化后点制于氨基修饰的载玻片上,制备基因芯片;靶基因用cy3标记引物,进行不对称PCR扩增,扩增的荧光标记单链产物与芯片杂交.不对称PCR结果显示,当限制性引物与非限制性引物浓度比例在1:10时ILTV-TK、NDV-HN和IBV-N的单链产物增加最多,当浓度比在1:20时,ILTV-gB、NDV-F和IBV-M的单链产物增加最多;相应的标记样品与3种病毒检测芯片杂交后,均出现较强的杂交信号,而阴性对照检测不到荧光信号,灵敏性实验表明,当DNA浓度为1.8x 104拷贝时杂交仍为阳性.本研究构建的诊断基因芯片对12份临床样品进行初步应用检测,与PCR检测技术检出率基本一致.本实验所建立的联合检测基因芯片能够快速、准确、高通量的诊断NDV-IBV-ILTV,可以应用于集约化养殖业中对多种鸡疫病病毒的检测.     

Using kale (Brassica oleracea var. acephala) as a phytoremediation plant species for lead (Pb) and cadmium (Cd) removal in saline soils

Ornamental kale (Brassica oleracea var. Acephala) is usually planted from early autumn until late winter. Since most of the plants used for phytoremediation cannot be grown during this time, kale can be a suitable option for phytoremediation and utilized during autumn and winter in urban landscape, especially in metropolitan areas where high levels of cadmium (Cd) and lead (Pb) pollutions exist. Kale growth in saline soil at different growth stages (germination and vegetative growth stages) was studied in this investigation. A factorial experiment based on completely randomized design (CRD) with four replications was used in this study. Treatments included three levels of sodium chloride (NaCl) (0, 30, and 60 mg/kg), four levels of Cd (0, 4, 8, and 16 mg/kg), and four levels of Pb (0, 1, 5, and 10 mg/kg). Results indicated that increase in Cd and Pb concentrations in the soil decreased fresh and dry weights of the plants. The results of the various growth stages revealed that under salinity stress, kale plants were able to absorb more Pb than Cd and effectively remediate Pb in polluted and saline lands. Cd accumulation in control treatment was 6.2% more than that in the saline treatments, whereas, Pb accumulation in the highest NaCl level, 60 mg/kg salinity treatment was 7.64% more than that of the control condition. Also, proline content of the plants was significantly increased under Cd and Pb stress. From the results of this study, it was concluded that using kale plant is recommended for phytoremediation of saline soils with 10 and 16 mg/kg Pb and Cd contents, respectively.     

茶树脱水素基因(CsDHN)的克隆及表达分析

脱水素(dehydrins,DHNs)是植物胚胎发育后期丰富蛋白(late embriogenesis abundant protein,LEA)中的一类,与低温、干旱以及盐胁迫等多种逆境反应相关.本研究采用cDNA末端快速扩增(rapidamplification of cDNA ends,RACE)技术从茶树(Camellia sinensis)中获得一种茶树脱水素基因CsDHN (GenBank登录号:FJ436978),序列分析显示,该基因cDNA全长960 bp,编码201个氨基酸,推测编码蛋白质分子量约为21kD,等电点为8.3,属于Y3SK2型脱水素.CsDHN基因有2个外显子和1个内含子.生物信息学预测显示,该脱水素蛋白亲水性强、无信号肽和跨膜区,亚细胞定位于细胞质中.表达特性分析表明,CsDHN在逆境及脱落酸(abscisic acid,ABA)诱导下可上调其转录水平,4℃低温处理下表达量可提高4.2倍,而脱水处理能提高93.4倍,高盐处理能提高17.8倍,CsDHN对脱水、高盐胁迫的响应程度优于低温胁迫.CsDHN在茶树各组织器官中都有表达,其中种子中表达量最高,为叶片的11.2倍.研究表明脱水素基因CsDHN可能在茶树防御非生物逆境胁迫和参与茶树种子成熟脱水的活力保护过程起一定作用,为了解茶树抗逆分子机制提供了一定的理论基础.     

锌指核酸酶(ZFN)介导的牛肌肉抑制素基因(MSTN)突变的研究

肌肉生成抑制素(myostatin,MSTN)是肌肉发育的负调控基因,突变后会引起肌肉的过度发育,在肉用动物育种中有非常重要的价值。本研究利用锌指核酸酶(zinc finger nuclease,ZFN)对牛(Bos taurus)MSTN基因的第二外显子特异性剪切,诱导该基因的突变,从而达到敲除该基因的目的。首先对脂质体介导的双质粒共转染牛成纤维细胞的条件进行优化,获得的共转染效率高达19.27%;之后利用两组ZFNs对牛成纤维细胞进行转染,单细胞通过口吸法移入96孔板,经扩大培养后进行PCR筛选,获得18株MSTN基因突变细胞株,其中包括一株双等位基因敲除的细胞系,两组ZFNs对牛成纤维细胞的突变效率分别为6.05%和3.84%;最后,挑选一株突变细胞系进行体细胞核移植研究,共获得24枚重构胚;将去除透明带的重构胚培养于2i培养液中,获得囊胚来源的类滋养层干细胞,通过PCR和测序检测,证明该细胞系在MSTN基因第二外显子具有与供体细胞相同的突变。结果表明,所合成的两组ZFNs可以在MSTN作用位点引起突变,具有很高的突变效率,而且能获得双等位基因突变的细胞株,获得的细胞株能够用作体细胞核移植的供体细胞。本研究为肉用牛的品质改良和育种工作提供了基础资料。     

表达播娘蒿突变基因DsALS-108的抗苯磺隆甘蓝型油菜植株构建

利用化学杀雄剂如苯磺隆(tribenuron-methyl,TBM)除草剂诱导雄性不育,是甘蓝型油菜(Brassicanapus)杂种优势应用的主要途径之一.选育具有TBM除草剂抗性的甘蓝型油菜作为父本,有利于简化制种程序,降低制种成本,对提高甘蓝型油菜的产量和品质具有重要意义.乙酰乳酸合成酶(acetolactate synthase,ALS)是合成支链氨基酸(缬氨酸、亮氨酸和异亮氨酸)的关键酶.ALS抑制类除草剂以乙酰乳酸合成酶为靶标,通过抑制其活性阻碍支链氨基酸的合成,导致植株死亡.TBM属于一种磺酰脲类(sulfonylureas,SU) ALS抑制类除草剂.为了改良甘蓝型油菜抗除草剂的遗传特性,本研究首先从一个抗TBM除草剂的播娘蒿(Descurainia sophia)天然突变体(#108)中克隆了ALS基因(GenBank登录号:EU520490),命名为DsALS-108.和拟南芥(Arabidopsis thaliana)乙酰乳酸合成酶AtALS蛋白序列的比对结果显示,保守氨基酸位点脯氨酸197在突变型蛋白DsALS-108中替换为苏氨酸(即P197T).为了验证含有P197T突变的DsALS-108基因是否使植株产生TBM除草剂抗性的原因,构建表达载体PBI 121-DsALS-108,并通过农杆菌(Agrobacterium tumefaciens)介导法将该载体转化拟南芥,共获得12个阳性转基因株系.喷洒浓度大于等于1.0× 10-4 g/L TBM后,野生型植株停止生长,趋于死亡,而拟南芥转化植株均能正常生长,说明表达突变基因DsA LS-108致使拟南芥植株抗TBM除草剂.在甘蓝型油菜转化中,以下胚轴为外植体,通过农杆菌介导法将载体pCAMBIA3301-DsALS-108导入甘蓝型油菜中,共获得23个阳性转基因株系.结果发现,DsALS-108的表达使甘蓝型油菜对苯磺隆的抗性提高至野生型致死浓度的3倍,即7.5×10-3g/L.而且,当用化学杀雄使用剂量(0.05 mg/L TBM)处理甘蓝型油菜转化植株后,其花粉育性正常,说明该转化植株可作为父本应用于化学诱导的雄性不育系统,进行杂交制种.本研究为利用化学诱导的雄性不育系统实现杂种优势提供新材料.     

The relative efficiency of ionic iron(III) and iron(II) utilization by the rice plant

Uptake of iron by rice plants was equally rapid when supplied as ionic iron(II) or iron(III) at pH 3 and 4. Iron(III) uptake was reduced at pH 5 and uptake of iron when supplied as FeEDTA was relatively low at all three pH levels.

At pH 4 in the presence of plant roots, reduction of iron(III) to iron(II) occurred as indicated by Fe²⁺ BPDS formation. BPDS in a 3:1 ratio to iron(III) suppressed iron uptake by about 70%. The reduction was observed to be located in the endodermis of young roots and exodermis of older roots.

A capacity to oxidize iron(II) at the root surface was also observed under local anaerobic and relatively high pH conditions.

The significance of these two counteracting processes in affecting the oxidation state of iron at the root surface is discussed.     

促性腺激素释放激素基因(GnRH)和生长激素基因(GH)对番鸭产蛋性能的遗传效应分析

促性腺激素释放激素(GnRH)和生长激素(GH)分别是下丘脑-垂体-性腺轴(HPG)与GH/IGF轴分泌的激素,共同参与调控动物的繁殖性能。本研究以白羽番鸭(Cairina moschata)RF系为实验材料,采用PCR-SSCP技术进行基因分型,同时建立适合的线性统计模型,分析基因型与产蛋性能的关联性。结果表明,GnRH基因5’调控区检测到3种基因型AA/AB/BB,经测序比对AA型与BB型相比发生G→A突变,不同基因型与300日龄产蛋数和最大连产天数均显著相关(P<0.05),与开产日龄无显著相关(P>0.05);GH基因内含子3检测到3种基因型CC/CD/DD,经测序比对CC型与DD型相比发生A→G突变,不同基因型与最长连产天数显著相关(P<0.05),与300日龄产蛋数和开产日龄均无显著相关(P>0.05)。两个基因发挥作用的方式主要为加性效应,GnRH基因对300日龄产蛋数和最大连产天数的加性效应值分别为-3.53和-3.33,GH基因对最大连产天数的加性效应值为-2.44。推测GnRH和GH基因是与繁殖主效基因紧密连锁的标记基因。     

蛋鸭骨桥蛋白基因OPN的多态性与蛋品质性状的相关性研究

骨桥蛋白(osteopontin,OPN)是一种分泌型磷酸化蛋白,其可能在蛋壳形成过程中发挥作用。为了分析蛋鸭OPN基因单核甘酸多态性(SNPs)及其与蛋品性状的相关性,本研究以山麻鸭和绍兴鸭(Anas platyrhyncha domestica)各100个个体为研究材料,采用直接测序法进行OPN基因外显子7 SNPs的筛选。结果显示,山麻鸭中共发现8个突变位点,绍兴鸭有9个突变位点。在山麻鸭群体中,G544C、A671G,G672C、T761C和T873C 5处SNPs对部分蛋品性状有极显著或显著作用。而绍兴鸭群体中,A671G、G672C和T761C 3处SNPs对部分蛋品性状有极显著或显著作用。其中,山麻鸭A671G及G672C位点有3种基因型,对蛋壳厚度,BB型个体均值极显著高于其他基因型,对哈氏单位,AA型个体均值显著高于其他基因型。T761C位点有3种基因型,BB基因型对300日龄蛋壳厚度极显著优于AB/AB基因型。T873C位点,BB基因型在300日龄蛋壳厚度和蛋壳强度及500日龄蛋壳厚度、蛋壳强度和蛋壳重均高于其他基因型。因此推断,位点T761C的B等位基因和T873C的B等位基因为改善蛋品性状的有利基因。绍兴鸭A671G和G672C位点在500日龄蛋形指数方面,AB基因型均值极显著高于AA和BB基因型。在T761C位点,BB型和AB型的300日龄蛋壳强度和蛋壳厚度均值显著高于AA基因型,在500日龄蛋形指数、蛋重、蛋壳重和蛋内容物重4个性状上,AB基因型均值略高于AA基因型,极显著高于BB基因型。结果表明,OPN基因可作为蛋品性状分子标记,为蛋鸭的标记辅助选择育种提供基础资料。     

Effect of Predominant Integrated Nutrient Management Practices on Soil Quality Indicators and Soil Quality Indices under Post Monsoon (Rabi) Sorghum (Sorghum Bicolor) in Rainfed Black Soils (Vertisols) of Western India

A long-term study was conducted to study the impact of integrated nutrient management on soil quality in post-monsoon sorghum (Sorghum bicolor) at Solapur in Maharashtra State in Western India under All India Coordinated Research Project for Dryland Agriculture. The experiment was laid out with ten Integrated Nutrient Management Treatments in a randomized block design with three replications. The results of the study indicated that among all the integrated nutrient management treatments practiced, the application of 25 kg nitrogen (N) ha^?1 through crop residue (CR) + 25 kg N ha^?1 (urea) showed the highest soil quality index of 2.36, which was at par with other treatments receiving farmyard manure (FYM) and crop residues along with urea. The relative order of performance of the integrated nutrient management treatments in influencing soil quality was: T₆: 25 kg N ha^?1 (CR) + 25 kg N ha^?1 (urea) (2.36) >T₅: 25 kg N ha^?1 (FYM) (2.31) > T₇: 25 kg N ha^?1 (FYM) +25 kg N ha^?1 (urea) (2.30) = T₈: 25 kg N ha^?1 (CR) +25 kg N ha^?1 (Leucaena loppings) (2.30) > T₁₀: 25 kg N ha^?1 (Leucaena loppings) +25 kg N ha^?1 (urea) (2.17) > T₄: 25 kg N ha^?1 (CR:crop residues) (2.16) > T₉: 25 kg N ha^?1 (Leucaena loppings) (2.15) > T₃: 50 kg N ha^?1 (urea) (2.10) > T₂: 25 kg N ha^?1 (urea) (1.99) > T_1: 0 kg N ha^?1 (control) (1.77). The results of the study also indicated that average percent contribution of each soil key indicator towards soil quality indices was: pH (3.97%), EC (1.94%), organic carbon (18.6%), available P (2.80%), available K (6.57%), exchangeable Ca (7.02%), available S (3.45%), Available Zn (17.9%), dehydrogenase (DHA) (16.2%), microbial biomass carbon (MBC) (18.5%) and mean weight diameter (MWD) (3.14%). Thus, the results of the present study will be highly useful to the land managers in planning effective management of soil quality.     

自PGCs分离克隆哺乳动物ES细胞的研究进展

原始生殖细胞（PGCs）是哺乳动物各级生殖细胞的祖细胞。PGCs在体外合适的培养条件下，可自我更新，形成具有ES特征的多能干细胞系，称作胚胎生殖细胞（EG细胞）。EG细胞高度类似于ES细胞，PGCs可作为哺乳动物ES细胞分离克隆的一个有效替代途径，本研究对自PGCs分离克隆哺乳动物ES细胞的研究进展及其相关问题作一简述。     

Enhanced root uptake of acibenzolar-S-methyl (ASM) by tomato plants inoculated with selected Bacillus plant growth-promoting rhizobacteria (PGPR)

The combination of plant growth-promoting rhizobacteria (PGPR) and plant resistance inducers is an alternative crop protection approach in modern agricultural systems. Despite the numerous reports regarding the improved suppression of plant pathogens by their combined application, little is known about the interactions among these components. In the present study, the persistence behavior of the plant activator acibenzolar-S-methyl (ASM) in the rhizosphere of tomato plants and its root uptake as well as systemic translocation ability in aboveground parts after combined use with certain Bacillus PGPR strains (B. amyloliquefaciens IN937a, B. pumilus SE34, B. subtilis FZB24 and GB03) were investigated. Additionally, the population dynamics of the PGPR strain B. subtilis GB03 at the tomato root system and rhizosphere soil applied with or without the pesticide were studied. The results showed that the addition of PGPR inocula did not affect the dissipation rate of ASM in rhizosphere soil. Also, the formation of its major metabolite CGA 210007 in soil was rapid, since it was detected one hour after root drench and it was maintained at high levels during the sampling period without considerable variations among the bacterial treatments compared to the control. The uptake and systemic translocation of ASM and its metabolite CGA 210007 from root to shoot was rapid and maximum concentrations were observed at 48–96 h after its application. It was revealed that in plants treated with the PGPR strains B. subtilis GB03 and B. pumilus SE34 the uptake and systemic translocation of ASM and CGA 210007 in the aerial parts of the tomato plants was significantly higher compared to the control receiving no bacterial treatment. Also, the populations of the strain B. subtilis GB03 showed high colonizing ability in the root system and the rhizosphere soil. PGPR strains that lead to enhanced pesticide uptake by plants should be further evaluated as components in integrated management systems.