转双价抗虫基因毛白杨无性系85号抗虫性研究

以优化的毛白杨无性系85号最适遗传转化体系为基础,通过农杆菌介导法将Bt(CryⅠAc)和API双价抗虫基因导入毛白杨无性系85号基因组.在高浓度卡那霉素的培养基上诱导不定芽和根,初步选择到200株转化植株,PCR检测显示,66株呈阳性反应.Southern杂交和ELISA检测进一步证明,Bt(CryⅠAc)和API双价抗虫基因已整合到毛白杨无性系85号基因组中,并得到了表达.对转化植株用舞毒蛾幼虫进行饲虫试验,结果显示昆虫幼虫的死亡率高达60.0%~77.8%,且存活幼虫的生长发育也受到了明显抑制.研究结果为杨树抗虫育种提供了新的种质资源.     

The chemiluminescence immunoassay for aflatoxin B1 based on functionalized magnetic nanoparticles with two strategies of antigen probe immobilization

A rapid and sensitive chemiluminescence immunoassay (CLIA) based on magnetic nanoparticles (MNPs) was developed to detect aflatoxin B1 (AFB1), which is a potent carcinogen in nature. We prepared monodisperse MNPs (300 nm in diameter) according to the solvothermal synthesis reaction and the MNPs were coated with silica by the Stöber method. Triethox was used as a one‐step carboxylation reagent, and 3‐aminopropyltriethoxysilane (APTES) an amination reagent, to modify the MNPs. We prepared two types of solid phase antigens using the above synthesized functionalized MNPs coupled with the later prepared AFB1‐oxime active ester and the purchased BSA–AFB1 respectively. 2′,6′‐dimethylcarbonylphenyl‐10‐sulfopropylacridinium‐9‐carboxylate 4′‐N‐hydroxysuccinimide (4′‐NHS) ester (NSP–DMAE–NHS), as a novel luminescent reagent, was used to label anti‐AFB1 antibodies. The two CLIA calibration curves based on the two types of solid phase antigens were obtained and compared. The acquired limit of detection (LOD) was about 0.001 ng/mL for the two functionalized MNPs‐based immunoassays, and the half maximal inhibitory concentration (IC₅₀) was 0.51 ng/mL for the MNPs–AFB1‐based method and 0.72 ng/mL for the MNPs–BSA–AFB1‐based method.     

Does Bt rice pose risks to non‐target arthropods? Results of a meta‐analysis in China

Transgenic Bt rice expressing the insecticidal proteins derived from Bacillus thuringiensis Berliner (Bt) has been developed since 1989. Their ecological risks towards non‐target organisms have been investigated; however, these studies were conducted individually, yielding uncertainty regarding potential agroecological risks associated with large‐scale deployment of Bt rice lines. Here, we developed a meta‐analysis of the existing literature to synthesize current knowledge of the impacts of Bt rice on functional arthropod guilds, including herbivores, predators, parasitoids and detritivores in laboratory and field studies. Laboratory results indicate Bt rice did not influence survival rate and developmental duration of herbivores, although exposure to Bt rice led to reduced egg laying, which correctly predicted their reduced abundance in Bt rice agroecosystems. Similarly, consuming prey exposed to Bt protein did not influence survival, development or fecundity of predators, indicating constant abundances of predators in Bt rice fields. Compared to control agroecosystems, parasitoid populations decreased slightly in Bt rice cropping systems, while detritivores increased. We draw two inferences. One, laboratory studies of Bt rice showing effects on ecological functional groups are mainly either consistent with or more conservative than results of field studies, and two, Bt rice will pose negligible risks to the non‐target functional guilds in future large‐scale Bt rice agroecosystems in China.     

杜氏盐藻rbcS启动子的克隆和功能分析

为提高转基因盐藻的表达效率,利用基因组步行方法和巢式PCR,从盐藻中克隆了1,5-二磷酸核酮糖羧化酶/加氧酶（Rubisco）的小亚基基因rbcS 的5'上游调控序列,并对其进行序列分析和转基因功能分析。采用Dra I、EcoR V、Pvu II和Stu I四种平端限制内切酶分别酶切盐藻基因组DNA,并与接头连接,构建基因组步行文库GWL 1、GWL 2、GWL 3和GWL 4;设计特异引物从这四种文库中扩增rbcS基因的5'上游调控序列。在GWL 1、GWL 4中分别扩增出约1.2 kb的片段。对该序列的分析表明,它的3'端与已知盐藻rbcS cDNA 的5'端序列完全一致,说明是该基因的5'端上游区,并且包含多个与转录调控有关的保守序列（如TATA-box、CAAT-box）,富含GT的重复序列。此序列EcoR I下游的片段与除草剂抗性基因bar相融合,构建表达载体,电击法转化盐藻。通过对转化藻株的抗性筛选以及PCR和Southern blot检测,表明该区域能驱动外源基因bar在转基因盐藻中的表达,推断是盐藻rbcS基因的启动子调控区。     

不同pH水平下两种菌根真菌对紫云英生长的影响及其相互作用

设计在不同pH水平（4.3、5.1、5.8、6.8）下两种VA菌根真菌Glomus mosseae和Gigaspora margarita对紫云英Astragalus sinicus进行单接种、混合接种及无接种对照的盆栽实验。对紫云英地上和地下部分生物量、根部侵染率、SDH和ALP酶活进行了检测。实验结果表明：紫云英的生长效应与VA菌根真菌的侵染率及两种酶活成明显相关性。土壤pH升高,单接种Glomus mosseae和混合接种的侵染率也随之升高,而单接种Gigaspora margarita的侵染率呈现     

新型战伤急救止血剂体内抗菌活性的实验研究

目的：探讨新型战伤急救止血剂对家兔急性感染伤口的抗菌作用。方法：选用兔感染创面模型,分新型战伤止血剂、5A沸石、Quiclot和空白对照组对创面进行治疗,通过组织学观察、组织内细菌计数等方法对各组抗菌性能进行研究。结果：肉眼和组织学观察新型战伤急救止血剂治疗组动物模型伤口,炎症反应均小于其他各组;新型战伤急救止血剂治疗组织内细菌计数为104,比其他3组显著减少（P〈0.01）。结论：新型战伤急救止血剂具有良好的体内抗菌性能。     

Tracing the transition of methicillin resistance in sub-populations of Staphylococcus aureus, using SELDI-TOF Mass Spectrometry and Artificial Neural Network Analysis

Strains (n = 99) of Staphylococcus aureus isolated from a large number of clinical sources and tested for methicillin sensitivity were analysed by MALDI-TOF-MS using the Weak Cation Exchange (CM10) ProteinChip Array (designated SELDI-TOF-MS). The profile data generated was analysed using Artificial Neural Network (ANN) Analysis modelling techniques. Seven key ions identified by the ANNs that were predictive of MRSA and MSSA were validated by incorporation into a model. This model exhibited an area under the ROC curve value of 0.9147 indicating the potential application of this approach for rapidly characterising MRSA and MSSA isolates. Nearly all strains (n = 97) were correctly assigned to the correct group, with only two aberrant MSSA strains being misclassified. However, approximately 21% of the strains appeared to be in a process of transition as resistance to methicillin was being acquired.     

Binding,internalization, and degradation of antiproliferative heparan sulfate by human embryonic lung fibroblasts

Binding, internalization, and degradation of ¹²⁵I-labeled, antiproliferative, or nonantiproliferative heparan sulfate by human embryonic lung fibroblasts was investigated. Both L-iduronate-rich, antiproliferative heparan sulfate species as well as L-iduronate-poor, inactive ones were bound to trypsin-releasable, cell-surface sites. Both heparan sulfate types were bound with approximately the same affinity to one high-affinity site (K_d approximately 10⁻⁸ M) and to one (K_d approximately 10⁻⁶ M), respectively. Results of Hill-plot analysis suggested that the two sites are independent. Competition experiments with unlabeled glycosaminoglycans indicated that the binding sites had a selective specificity for sulfated, L-iduronate-rich heparan sulfate. Dermatan sulfate, which is also antiproliferative, was weakly bound to the cells. The antiproliferative effects of heparan and dermatan sulfate appeared to be additive. Hence, the two glycosaminoglycans probably exert their effect through different mechanisms. At concentrations above 5 μg/ml (approximately 10⁻⁷ M), heparan sulfate was taken up by human embryonic lung fibroblasts, suggesting that the low-affinity site represents an endocytosis receptor. The antiproliferative effect of L-iduronate-rich heparan sulfate species was also exerted at the same concentrations. The antiproliferative species was taken up to a greater degree than the inactive one, suggesting a requirement for internalization. However, competition experiments with dextran sulfate suggested that both the high-affinity and the low-affinity sites are involved in mediating the antiproliferative effect. Structural analysis of the inactive and active heparan sulphate preparations indicated that although sulphated L-iduronate appears essential for antiproliferative activity, it is not absolutely required for binding to the cells. Degradation of internalized heparan sulfate was analyzed by polyacrylamide gel electrophoresis using a sensitive detection technique. The inactive species was partially degraded, whereas the antiproliferative one was only marginally affected. J. Cell. Biochem. 64:595–604. © 1997 Wiley-Liss, Inc.