红菜薹游离小孢子培养技术研究

对影响红菜薹游离小孢子培养的关键因素进行分析。研究结果表明,不同红菜薹材料之间的小孢子胚诱导率差异很大;4℃低温预处理2h对小孢子胚的形成具有促进作用;NLN培养基中添加生长素(NAA)和细胞分裂素(6-BA)对小孢子胚诱导率影响不大,添加浓度过大时诱导率反而降低;培养基中添加活性炭能提高小孢子胚诱导率;子叶型胚在15g/L琼脂的培养基上直接成苗率最高,达56.7%;再生植株在MS和1/2MS IBA(0.5mg/L)中的生根能力最好,1/2MS生根效果其次。     

红籽瓜主要产量性状的遗传力及相关性分析

以红籽瓜农家品种及自交系为供试材料,采用随机区组试验设计,用方差分析法估算了单株坐瓜数、单瓜重、单瓜种子数、单瓜种子重、种仁重、千粒重、出仁率、产籽率和种子体积的广义遗传力;并对43个红籽瓜品种9个产量性状的遗传力、遗传变异系数和相关性进行了研究。结果表明,上述9个产量性状的广义遗传力分别为12.86%,80.14%,75.96%,74.39%,48.01%,17.12%,24.97%,18.60%和37.07%。单瓜重、单瓜种子数和单瓜种子重的遗传力较高,对其进行早世代单株选择有较好的效果;遗传变异系数以千粒重和出仁率较高,选择潜力大。性状间相关性的研究表明:通过对单瓜重的选择,可实现对单瓜种子数、单瓜种子重、种仁重和种子体积等性状的间接选择。并对红籽瓜产量性状遗传力分析结果及其在育种中的应用进行了讨论。     

瓢鸡3个防御素基因（AvBD4、AvBD5、AvBD14）的Bi-PASA分子标记与沙门菌易感性的相关性研究

研究以3个防御素基因(AvBD4、AvBD5、AvBD14)为鸡沙门菌易感性候选基因,以瓢鸡成年鸡沙门菌阳性群体与阴性对照群体为研究对象,采用序列测定和双向PCR扩增特异等位基因标记(Bi-PASA)技术,分析了3个防御素基因变异与沙门菌易感性的相关性。结果显示:在瓢鸡每个防御素基因编码区均检测到一个引起氨基酸变异的多态位点,分别建立了3个防御素基因的Bi-PASA分子标记;AvBD5基因A799G位点与瓢鸡沙门菌易感性的相关性达到极显著水平(P=0.0039),AvBD14基因的A2096T位点达到显著水平(P=0.017),而AvBD4相关性不显著(P=0.599);根据比值比(OR)与95%CI确定了每个防御素基因的保护基因型与易感基因型。研究结果对阐明防御素基因与沙门菌易感性的关系以及建立沙门菌抵抗力鸡群具有重要意义。     

氮磷肥配施对西北羊茅开花期叶片光合特性日变化的影响

基于植物对N、P营养元素的需求,试验设计2个施氮量(0、60 kg·hm^-2)和3个施磷量(0、60、90 kg·hm^-2)配施,测定开花期叶片在不同光合有效辐射下的气体交换参数和叶绿素荧光参数,探讨西北羊茅对氮、磷添加和光合有效辐射的响应。结果表明,光合有效辐射呈先增后减的日动态变化,下午13:00时高达2000 μmol·m^-2·s^-1,且对西北羊茅光合特性的影响大于施肥措施。净光合速率随光合有效辐射增强先增后降,其值在800~1000 μmol·m^-2·s^-1时最大;气孔导度、气孔限制值、蒸腾速率和水分利用效率与净光合速率表现一致,胞间CO₂浓度表现相反。氮肥和磷肥配施后气孔导度、气孔限制值和蒸腾速率均增大,胞间CO₂浓度则减小,表明施肥主要通过调节气孔导度,以促进叶片与环境间交换水分和CO₂,从而增大净光合速率。随光合有效辐射增强,PSⅡ有效光化学效率、PSⅡ实际光化学效率和光化学猝灭系数显著降低,非光化学猝灭系数显著增加,电子传递速率先增加后降低,但均在400~800 μmol·m^-2·s^-1和大于1200 μmol·m^-2·s^-1后快速变化。氮肥和磷肥配施显著提高PSⅡ有效光化学效率、PSⅡ实际光化学效率、光化学猝灭系数和电子传递速率,N₆₀P₉₀处理还提高PSⅡ最大光化学效率和非光化学猝灭系数。在光能分配方面,为减轻强光对光合器官的破坏,随光合有效辐射增强光化学反应比例降低,天线热耗散和非光化学反应耗散比例增加。施肥主要通过非光化学反应比例减小补偿于光化学反应比例,从而提高光能利用率。综合以上结果,从西北羊茅叶片的光合特性来看,氮磷肥配施通过调节气孔导度,以促进叶片与环境间水分和CO₂的交换和提高PSⅡ反应中心活性,非光化学反应比例减小补偿于光化学反应比例,进而增加叶片净光合速率。     

狐肺炎大肠杆菌毒力基因和耐药基因检测及药物敏感性分析

为了解河北地区狐肺炎大肠杆菌毒力基因、耐药基因的分布及耐药性情况,本研究采用PCR技术对从狐肺炎病例分离的81株大肠杆菌的毒力基因和耐药基因进行检测,采用K-B法检测这些大肠杆菌对16种抗菌药物的敏感性,采用试管二倍稀释法检测中药对大肠杆菌的最小抑制浓度(MIC)和最小杀菌浓度(MBC),采用腹腔注射法检测81株大肠杆菌对小白鼠的致病性。结果显示:此次共分离到81株大肠杆菌,且对小白鼠具有较强致病性;毒力基因irp2、fyuA、Ler、eaeA检出率分别为50.6%、56.8%、9.9%、23.5%;耐药基因blaTEM、blaOXA1、sul1、sul2、blaTEM1、blaSHV-1、blaCTX-M、strA-strB、aadA1、blaPSE1、sul3、tetA、tetB、tetC、tetD、ermF检出率分别为84.0%、69.1%、43.2%、38.3%、28.4%、4.9%、24.7%、29.6%、16.1%、9.9%、11.1%、9.9%、18.5%、8.6%、13.6%、3.7%,未检出耐药基因ermB、ermC;81株大肠杆菌均对磺胺间甲氧嘧啶、林可霉素等耐药;诃子、乌梅、五味子对81株大肠杆菌具有较好的体外抑菌作用,抑菌圈直径在20 mm～36 mm,MIC和MBC在7.81 mg/mL～62.50 mg/mL。本研究调查了河北地区狐肺炎大肠杆菌的流行情况,对狐肺炎病的防治具有重要的指导意义,更具公共卫生学意义。     

Tumour necrosis factor‐related apoptosis‐inducing ligand induces apoptosis in canine hemangiosarcoma cells in vitro

Tumour necrosis factor‐related apoptosis‐inducing ligand (TRAIL) is an apoptosis‐inducing cytokine that shows potential therapeutic value for human neoplasms, and is effective in some canine tumours; however, its potential for killing canine hemangiosarcoma (HSA) cells is unknown. Thus, we evaluated the proapoptotic effect of TRAIL in nine canine HSA cell lines. Cells (JuA1, JuB2, JuB2‐1, JuB4, Re11, Re12, Re21, Ud2 and Ud6) were cultured with three recombinant human TRAILs (rhTRAILs): TRAIL‐TEC derived from Escherichia coli, TRAIL‐TL derived from mammalian cells and isoleucine zipper recombinant human TRAIL (izTRAIL) containing an isoleucine‐zippered structure that facilitates trimerization. TRAIL‐TEC did not decrease the cell viability in any of the cell lines tested, whereas the other two rhTRAILs effectively decreased the viability of all cell lines as assessed by the WST‐1 assay. In canine HSA cells, izTRAIL induced apoptosis more effectively than TRAIL‐TL. In JuB4, Re12, and Ud6 cells, izTRAIL increased the activation of caspase‐3 and caspase‐8 and caused poly (ADP‐ribose) polymerase degradation. Moreover, izTRAIL treatment increased the proportion of Annexin V+/ Propidium iodide (PI)? apoptotic cells and nuclear fragmentation in izTRAIL‐sensitive cells. These results show that rhTRAIL can induce apoptosis in canine HSA cells, but the sensitivity of TRAIL was different depending on the cell lines. Therefore, TRAIL could be an effective therapeutic agent against canine HSA, but the specific mechanism of resistance should be determined to clarify under what conditions this treatment would be most effective.     

Disease severity and pathotype dynamics of Puccinia striiformis f.sp. tritici in Denmark

Disease severity of wheat yellow rust, Puccinia striiformis f.sp. tritici , was analysed in Denmark from 1985 to 1999 in relation to the effects of weather on winter survival, distribution of host cultivars and pathotype dynamics. Below-average temperatures in January and February (midwinter) reduced yellow rust on the susceptible cv. Anja, and in three of four growth seasons following cold winters no yellow rust was observed on any cultivar under natural conditions. The agronomic consequences of dispersal of yellow rust urediniospores from external sources to Denmark, in a period during which large areas were planted with relatively few wheat cultivars, were demonstrated in several cases, most evidently when the Yr9 and Yr17 resistance genes became ineffective. Yr9 was overcome by the pathogen in a period with severe yellow rust epidemics on commercial cultivars, while virulence for Yr17 was first observed in a year with almost no yellow rust. In contrast, the resistance in cv. Kraka ( Yr1, CV ) was increasingly effective in controlling yellow rust, because pathotypes with the matching combination of virulence declined in the pathogen population. Pathotype frequency dynamics were thus influenced by selection forces within the country, and by selection forces in areas where spores were spread to Denmark from outside. The importance of a sufficient level of partial resistance in the wheat germplasm to prevent too much damage by yellow rust epidemics, in the event that the resistance genes are overcome by the pathogen population, is emphasized.     

甘南高寒草甸群落花期物候研究

对草地群落物候的研究,不仅有助于对草地群落功能认知,更重要的是为生态系统评估提供背景资料。本研究从地理环境因素、功能性状、传粉者竞争以及系统发育4个方面讨论影响甘南高寒草甸植物花期物候的因素。结果表明,在群落水平上,开花期涵盖了整个生长季,但在整体上有一个高峰期,群落中各物种的始花期、开花峰值期及开花持续期不同,每一物种均有其独特的花期格局;植株高度(P0.001)和种子大小(P=0.034)能够显著地预测开花,而比叶面积(SLA)则不显著(GLM,P0.05);风媒物种开花期早于虫媒物种(P=0.008);花期物候重叠与系统发育距离之间存在着负相关关系。     

Research advance of PDSS2 gene on carcinoma

Prenyl diphosphate synthase subunit 2 (PDSS2), which encodes the second subunit of prenyl diphosphate synthase, an essential enzyme involved in the biosynthesis of coenzyme Q10 (CoQ10), is almost expressed in all tissues and organs at different developmental stages of human beings. The abnormal expression of PDSS2 may result in many diseases through impacting the biosynthesis of CoQ10. Recent studies show that PDSS2 gene has decreased in melanoma, gastric cancer, lung cancer and hepatocellular carcinoma, and the degree of reduced level is closely related to the clinical features, which enlighten us that PDSS2 maybe a tumor suppressor gene involves in the development and progression of carcinoma. This review aims to introduce the recent research progress about PDSS2 gene on carcinoma, discuss its roles and value on cancer research.