羧化壳聚糖在蚊净香草组培中的应用研究

本文研究羧化壳聚糖在蚊净香草组培中的应用。试验结果表明,在诱导培养基中附加2 g/L羧化壳聚糖,有利于提高蚊净香草诱导率;附加4 g/L羧化壳聚糖,试管苗增殖率达6倍,且根系发达。     

Robustness of neural codes and its implication on natural image processing

In this study, based on the view of statistical inference, we investigate the robustness of neural codes, i.e., the sensitivity of neural responses to noise, and its implication on the construction of neural coding. We first identify the key factors that influence the sensitivity of neural responses, and find that the overlap between neural receptive fields plays a critical role. We then construct a robust coding scheme, which enforces the neural responses not only to encode external inputs well, but also to have small variability. Based on this scheme, we find that the optimal basis functions for encoding natural images resemble the receptive fields of simple cells in the striate cortex. We also apply this scheme to identify the important features in the representation of face images and Chinese characters.

害虫防治决策的复序贯分析方法及抽样技术研究

复序贯抽样决策技术实际应用的受限 ,原因在于截止限序贯抽样模型的缺乏。本文在检验昆虫种群空间格局回归模型的基础上 ,推导出了目前国内常用检验回归模型的截止限序贯抽样模型 ,并将其运用于复序贯分析决策过程中。实例分析表明 ,对于同一种生物种群 ,在一定的精度 (D)和置信水平(tα)要求下 ,复序贯抽样决策技术可以大幅度地节约抽样成本     

人发角蛋白人工腱材料体内降解及生物相容性研究

目的研究人发角蛋白人工腱(humanhairkeratinartificaltendon,HHKAT)材料在体内的可降解性及其生物相容性.方法对12只日本大耳白兔随机分组,在脊旁肌埋藏不同处理时间的人发角蛋白人工腱试件F及Z,用正常人发O做对照,分别在2、6、12、24周取材,观察人发角蛋白的降解吸收过程及其周围的组织反应.结果动物植入实验中发现不同时间处理的材料其降解速度不同,其中降解最快的F组在24周已完全吸收,而Z组在24周只有部分降解,O组未见降解.HHKAT及人发在肌肉组织内无明显的炎症排斥反应,随着HHKAT材料的降解吸收,其周围的组织反应逐渐降低.结论本研究表明人发角蛋白人工腱材料具有良好的生物相容性,在体内能够被降解吸收,可根据不同的需要调节其降解速度,是良好的肌腱替代材料.     

逆转录病毒载体介导诱导型NO合酶在神经细胞中表达

为了深入研究诱导型一氧化氮合酶基因表达产物在阿片耐受和依赖中作用,采用脂质体介导基因转染技术,将ｉＮＯＳ ｃＤＮＡ重组逆转录病毒载体导入ＮＧ１０８－１５神经细胞,获得Ｇ４１８抗性克隆,命名为ＮＧ－ＬＮＣＸｉＮＯＳ细胞。ＤＮＡ印迹杂交,ＰＣＲ扩增及ＲＴ－ＰＣＲ和蛋白质免疫印迹杂交分析,证实ＮＧ－ＬＮＣＸｉＮＯＳ细胞有外源ｉＮＯＳ基因整合,转录和表达;ＮＡＤＰＨ黄递酶（ＮＡＤＰＨ ｄｉａｐｈｏｒａｓｅ     

Molecular cloning and expression analysis of RrNHX1 and RrVHA-c genes related to salt tolerance in wild Rosa rugosa

Salt stress is one important factor influencing the growth and development of plants, and salt tolerance of plants is a result of combined action of multiple genes and mechanisms. Rosa rugosa is not only an important ornamental plant, but also the natural aromatic plant of high value. Wild R. rugosa which is naturally distributed on the coast and islands of China has a good salt tolerance due to the special living environment. Here, the vacuolar Na⁺/H⁺ reverse transporter gene (NHX1) and the vacuolar H⁺-ATPase subunit C gene (VHA-c) closely related to plant salt tolerance were isolated from wild R. rugosa, and the expression patterns in R. rugosa leaves of the two genes under NaCl stress were determined by real-time quantitative fluorescence PCR. The results showed that the RrNHX1 protein is a constitutive Na⁺/H⁺ reverse transporter, the expression of the RrNHX1 gene first increased and then decreased with the increasing salt concentration, and had a time-controlled effect. The RrVHA-c gene is suggestive of the housekeeping feature, its expression pattern showed a similar variation trend with the RrNHX1 gene under the stress of different concentrations of NaCl, and its temporal expression level under 200 mM NaCl stress presented bimodal change. These findings indicated that RrNHX1 and RrVHA-c genes are closely associated with the salt tolerance trait of wild R. rugosa.     

不同光质光对葡萄愈伤组织增殖和白藜芦醇含量的影响

研究不同光质影响‘黑比诺’种子诱导并继代10个月的葡萄愈伤组织增殖及白藜芦醇含量的结果表明：不同光质下愈伤组织的增殖顺序依次为黄光〉绿光〉红光〉蓝光〉白光;白藜芦醇的含量依次为白光〉黄光〉红光〉蓝光〉绿光：白藜芦醇的生产量是白光〉黄光〉红光〉蓝光〉绿光。     

A multi-generation analysis of the stability of transgenic virus resistance in doubled-haploid tobacco lines

Plants can be genetically engineered for virus resistance by transformation with a viral gene. We transformed tobacco with the tomato spotted wilt virus (TSWV) nucleocapsid gene from the Hawaiian L isolate in order to obtain TSWV resistant breeding lines. Doubled-haploid lines were produced from primary transgenic plants that were selected for resistance to the virus. Several of these lines showed very high levels of resistance and were symptomless after inoculation with the Hawaiian L isolate of TSWV. The accumulation of only low levels of full-length transgene RNA and protein observed in these lines is consistent with an RNA-mediated mechanism of resistance. The lines that were highly resistant to the Hawaiian L isolate of TSWV were also found to be highly resistant to several other isolates of TSWV, while lines that were only moderately resistant to the Hawaiian L isolate were often susceptible to the other isolates. The highly resistant lines were advanced over several generations by self-pollination. Although these lines were fully homozygous, several lines lost resistance in later generations, indicating that the resistance was unstable. Selection for resistance in these unstable lines did not prevent the occurrence of susceptible progeny in subsequent generations. Therefore, testing over several generations is required to determine the stability of resistance when breeding crops with transgenic virus resistance.     

西藏拉萨地区三叠系诺利阶牙形石分带及其国际对比

麦龙岗剖面位于西藏拉萨地区达孜县麦龙岗村 (N2 9°5 6′0 6″ ,E91°2 7′5 5″)。麦龙岗组中共发现牙形石 7属 :Epigondolella ,Hindeodella ,Priniodella ,Xaniognathodus,Lonchodina ,Metalonchodina和Enantiognathus属。其中Epigondolella属有 9种 ,包括 1新种和 1未定种 ,它们是E .primitia ,E .spiculata ,E .cf.spiculata ,E .tozeri,E .violinformissp .nov .,E .cf.triangularisuniformis,E .postera ,E .bidentata ,E .sp .。基于本次发现的化石材料 ,对西藏林周地区麦龙岗组进行新的牙形石带划分。自下而上划分为 :?Epigondolellaprimitia ,E .spiculata ,E .tozer i,E .postera和E .bidentata等带。与毛力等 (1987)、Orchard(1983,1991,1994 )和Krystyn(1977)的划分方案进行对比和讨论