树突状细胞在抗真菌感染免疫中的作用

近年来,随着广谱抗生素、抗肿瘤药物和免疫抑制剂等药物的广泛使用,免疫功能降低患者数量的增加,侵袭性真菌感染性疾病的发病率逐年升高。树突状细胞(Dendritic Cells,DCs)是已知功能最强的专职抗原提呈细胞,作为宿主固有免疫和适应性免疫的联系枢纽,DCs在病原微生物抗原的识别与呈递过程中发挥核心作用。研究证明,DCs可通过其细胞表面的多种受体有效识别病原真菌的抗原,并在诱导宿主免疫应答过程中发挥重要作用。本文将对树突状细胞分类及其在抗真菌感染免疫中的识别作用进行系统叙述。     

Nitrogen addition increases intraspecific competition in the invasive wetland plant Alternanthera philoxeroides,but not in its native congener Alternanthera sessilis

Nitrogen is often released in pulses with different frequencies, and N supply pulses may affect growth, reproduction, and biomass allocation of plants. However, few studies have examined how N supply pulses affect intraspecific competition of clonal plants and whether such an effect depends on the N supply amount. We grew one (no competition) or 12 ramets (with intraspecific competition) of both an invasive clonal plant Alternanthera philoxeroides and its native congener Alternanthera sessilis in five different N treatments: control (no N addition), low/high amount with low/high frequencies (pulses). Nitrogen addition significantly increased the growth of both species, while intraspecific competition decreased it. Nitrogen addition significantly increased intraspecific competitive intensity of A. philoxeroides as measured by the log response ratio of growth traits, but did not affect that of A. sessilis. Despite the N supply amount, N pulses had little effect on the growth and thus intraspecific competition of the two species. Therefore, increasing N deposition may change population structure and dynamics and the invasion succession of A. philoxeroides, but changes in N pulses may not.     

蝙蝠科三种蝙蝠的G-带和C-带

对肺、心等进行组织培养,用空气干燥法制作染色体标本,对贵州3种蝙蝠即中华鼠耳蝠(Myotis chinensis)、西南鼠耳蝠(M.altarium)和亚洲长翼蝠(Miniopterus fuliginosus)进行了G-带、C-带带型分析。结果表明,2种鼠耳蝠的G-带基本相同,亚洲长翼蝠的G-带与两种鼠耳蝠有一定同源性;C-带核型中,中华鼠耳蝠和亚洲长翼蝠只有着丝粒带,而西南鼠耳蝠有的染色体有插入C-带和端位C-带。根据带型异同分析讨论了鼠耳蝠和长翼蝠间的进化关系。     

顺德生态乐园之土壤及其合理利用建议

广东省顺德生态乐园内的土壤形成发育受气候、生物、地形地貌、母质母岩和人为干扰等５大因素的影响,其中人为活动是导致土层结构破坏和水土流失的主要原因。酸度高、肥力低、土质较好是园内土壤的一个共同特征。在各类土壤中,坡地赤红壤的面积最大,超过７０％,但坡项土层瘠薄。水稻土有较长耕作历史,并已形成了潜育层和潴育层,但土壤肥力并不高。泥炭土有较高的有机质含量,但土壤过酸,速效养分含量过低,难以直接利用。因此     

Analysis of the Maize 19 kD Zein Gene Promoter Fragment Driving Seed specific Expression

A deletion works of a maize 19 kD zein gene promoter in the 5'end was performed and six promoter fragments of different length were obtained. A series of expression vectors was constructed and then transferred into tobacco ( Nicotiarta tabacum L. ) plants. GUS activity assays indicated that the expression of 488 bp promoter was tissue-specific, for which GUS was active only in transgenic tobacco seeds. The other four fragments containing 378 bp,302 bp,152 bp and 124 bp also have the activity of promoter. They could drive gus gene expressed not only in seeds but also in roots and petioles.     

黔西北土法炼锌废弃地植被重建的限制因子

以土法炼锌废弃地的废渣、污染土壤和背景土壤为基质材料,分别种植黑麦草(Lolium perenne)和三叶草(Trifolium pretense),分析各种基质的基本化学特性、重金属(Pb、Zn、Cd)含量及其赋存形态、两种植物生长特性.结果表明,土法炼锌废渣上植被重建的主要限制因子包括高盐碱胁迫、有机质含量低、养分缺乏(TN、碱解N、TK).废渣重金属含量高,有效态含量低,对植物毒性小,但存在潜在危害性.污染土壤重金属含量低于废渣,但生物有效态重金属含量高.污染土壤植被重建的限制因子包括重金属毒性、P和K的有效性.废渣与污染土壤混合是土法炼锌废弃地基质改良的有效途径.     

帽儿山蕨类植物种群生态的研究

在深入调查研究的基础上, 首次报道了帽儿山地区的蕨类植物资源, 共计13 个科、23 个属和40 多个种, 根据各种群在生态上的不同要求, 以表格的形式说明了主要蕨类种群对"湿度"和"光照"因子的适应关系。本文还着重指出了各种群的生物学特性和生态环境的一致性, 并详细讨论了蕨类种群在山体中的适生生境。     

酵母PHO2与PHO4蛋白的激活活性的分析及两者的相互作用

ＰＨＯ２与ＰＨＯ４是酵母ＰＨＯ５基因的两个正调控因子,本文发现,ＰＨＯ２与酵母转录因子ＧＡＬ４的ＤＮＡ结合功能域融合后就能激活报道基因ｌａｃＺ的表达,其激活力受高低磷影响,表明ＰＨＯ２蛋白上存在酸性转录激活区。ＰＨＯ２蛋白上酸性氨基酸丰富的２８７－３２６肽段并非ＰＨＯ２的激活区。在ＰＨＯ２蛋白上２３０位Ｓｅｒ处于磷酸化状态２ＰＨＯ２才有激活作用,表明了这一磷酸化位点可能与ＰＨＯ２的转录激活能力有关     

Assembly of the sarcoplasmic reticulum proteins in differentiating rat skeletal muscle cell cultures: localization by immunofluorescence of sarcoplasmic reticulum proteins in differentiating rat skeletal muscle cell cultures

Immunofluorescent staining techniques were used to study the distribution of the Ca(2) + Mg(2+)-dependent ATPase and calsequestrin in primary cultures of differentiating rat skeletal muscle cells, grown for different periods of time under various culture conditions. In mononucleated myoblasts calsequestrin was detected after 45 h in culture whereas the ATPase was not detected until 60 h. After cell fusion began, both proteins could be identified in all multinucleated cells. Myoblasts grown for longer than 60 h in low Ca(2+) medium contained calsequestrin and the ATPase, even though they were unable to fuse. These studies at the cellular level confirm biochemical findings on the biosynthesis of calsequestrin and the ATPase. Immunofluorescent staining of myoblasts showed that calsequestrin first appears in a well-defined region of the cell near one end of the nucleus. At later times, the staining occupied progressively larger regions adjacent to the nucleus and took on a fibrous appearance. This suggests that calsequestrin first accumulates in the Golgi region and then gradually spreads throughout the cell. In contrast, the ATPase appeared to be concentrated in many small patches or foci throughout the cytoplasm and was never confined to one particular region, although some parts of the cell often stained more intensely than others. In multinucleated cells, alternating dark and fluorescent strands parallel to the longitudinal axis of the cells were evident.