水稻叶片在自然衰老过程中1，5-二磷酸核酮糖羧化酶/加氧酶的降解(英文)

１,５二磷酸核酮糖羧化酶／加氧酶（Ｒｕｂｉｓｃｏ）是光合碳同化的关键酶,研究其降解机理对合理调控水稻生长后期光合衰退具有重要意义。前人用人为诱导植物衰老的方法,研究了Ｒｕｂｉｓｃｏ的降解机理,认为该酶降解之前,必需发生亚基间的交联聚合和向类囊体膜转移,这样在结构和空间上有利于水解酶的作用。我们用自然衰老叶片进行研究的结果表明：Ｒｕｂｉｓｃｏ在降解过程中其比活基本保持恒定,意味着未发生酶的失活,也就是说酶结构未发生根本性改变,由此也可初步判断酶未发生亚基间的交联聚合（已证明亚基交联可导致酶失活）。接着用ＳＤＳＰＡＧＥ和蛋白印迹技术证实了上述观点：Ｒｕｂｉｓｃｏ降解之前只有极少量的大亚基聚合体,随后同未聚合大亚基一起很快降解。此外,研究结果进一步表明酶分子在降解之前有少量与叶绿体膜结合,但降解过程中并未见膜结合蛋白增加。根据上述结果我们认为,亚基间交联聚合和向膜转移并非水稻叶片自然衰老时Ｒｕｂｉｓｃｏ降解的必要条件。     

皖南、赣北早特马道克期Staurograptus的再研究

对皖南和赣北早奥陶世早特马道克期的Staurograptus重新研究表明,该属具有原始枝末端正分推迟、分支级数缩减和笔石枝密度降低的演化趋势,而代表不同演化阶段的三个种类,即Staurograptus dichotomus Emmons,S．apertus Ruedemann和S．hyperboreus Obut et Sobolevskaya,构成了该属基本的系统发育谱系。种群分析进一步显示,其主要性状变异范围尽管较宽但趋于正态分布的S．dichotomus,可能包含了除S．apertus和S．hyperboreus之外的所有已知Staurograptus的异名种类。     

双歧杆菌对免疫抑制小鼠白色念珠菌感染的保护作用

为探讨双歧杆菌对白色念珠菌感染的保护作用,作者采用环磷酰胺腹腔注射方法复制了免疫抑制小鼠模型,研究白色念珠菌感染前后两歧双歧杆菌灌饲的保护作用。结果表明：白色念珠菌感染前灌饲两歧双歧杆菌能有效地抑制白色念珠菌在小鼠肠道中的定植,并且保护肠粘膜的完整性。对其机理的研究认为,两歧双歧杆菌可能是通过调整肠道菌群平衡、增加肠道中生理菌群的数量、降低肠道ｐＨ值、以及产生抗菌物质等途径发挥保护作用     

雌激素Beta受体在大鼠脑内表达的免疫组化定位研究

为了探讨雌激素作用于神经系统的机理,采用硫酸镍铵增强显色的免疫组化SP法研究了新的雌激素受体(ER-β)在成年雌雄大鼠脑内的分布。研究证实ER-β免疫阳性物质主要位于神经元的细胞核内,但在个别脑区也可在胞浆甚至突起内检测到。最强的ER-β免疫阳性信号见于前嗅核、大脑皮质、小脑浦肯野细胞、斜角带垂直部、蓝斑和三叉神经运动核等部位;中等强度的染色见于隔内侧核、杏仁外侧核、黑质、中央灰质等部位;较弱的阳性反应见于下丘脑与杏仁复合体的部分核团。在一些部位还存在表达水平甚至细胞内定位模式的性别差异,如前庭上核内的表达只见于雌性;雄性大鼠三叉神经运动核内ER-β蛋白主要表达于胞浆内,细胞核为阴性;而在雌性大鼠该部位ER-β蛋白主要位于细胞核等。以上结果表明ER-β蛋白在大鼠脑内分布广泛并具有一定的性别差异,在与学习记忆有关的脑区如大脑皮质和基底前脑内有很高的表达,提示在脑组织内雌激素可能通过ER-β这一新的信号途径发挥多种重要的调控作用,如学习记忆等。     

The promoter of the pepper pathogen-induced membrane protein gene <Emphasis Type="Italic">CaPIMP1</Emphasis> mediates environmental stress responses in plants

The promoter of the pepper pathogen-induced membrane protein gene CaPIMP1 was analyzed by an Agrobacterium-mediated transient expression assay in tobacco leaves. Several stress-related cis-acting elements (GT-1, W-box and ABRE) are located within the CaPIMP1 promoter. In tobacco leaf tissues transiently transformed with a CaPIMP1 promoter-β-glucuronidase (GUS) gene fusion, serially 5′-deleted CaPIMP1 promoters were differentially activated by Pseudomonas syringae pv. tabaci, ethylene, methyl jasmonate, abscisic acid, and nitric oxide. The −1,193 bp region of the CaPIMP1 gene promoter sequence exhibited full promoter activity. The −417- and −593 bp promoter regions were sufficient for GUS gene activation by ethylene and methyl jasmonate treatments, respectively. However, CaPIMP1 promoter sequences longer than −793 bp were required for promoter activation by abscisic acid and sodium nitroprusside treatments. CaPIMP1 expression was activated in pepper leaves by treatment with ethylene, methyl jasmonate, abscisic acid, β-amino-n-butyric acid, NaCl, mechanical wounding, and low temperature, but not with salicylic acid. Overexpression of CaPIMP1 in Arabidopsis conferred hypersensitivity to mannitol, NaCl, and ABA during seed germination but not during seedling development. In contrast, transgenic plants overexpressing CaPIMP1 exhibited enhanced tolerance to oxidative stress induced by methyl viologen during germination and early seedling stages. These results suggest that CaPIMP1 expression may alter responsiveness to environmental stress, as well as to pathogen infection. The nucleotide sequence data reported here has been deposited in the GenBank database under the accession number DQ356279.     

Combinatory responses of proinflamamtory cytokines on nitric oxide-mediated function in mouse calvarial osteoblasts

Combinatory responses of proinflamamtory cytokines have been examined on the nitric oxide-mediated function in cultured mouse calvarial osteoblasts. Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) induced iNOS gene expression and NO production, although these actions were inhibited by L-NG-monomethylarginine (L-NMMA) and decreased alkaline phosphatase (ALPase) activity. Furthermore, NO donors, sodium nitroprusside (SNP) and NONOate dose-dependently elevated ALPase activity. In contrast, transforming-growth factor-β (TGF-β) decreased NO production stimulated by IL-1β, TNF-α and interferon-γ (IFN-γ). iNOS was expressed by mouse calvarial osteoblast cells after stimulation with IL-1β, TNF-α, and IFN-γ. Incubation of mouse calvarial osteoblast cells with the cytokines inhibited growth and ALPase activity. However, TGF-β-treatment abolished these effects of IL-1β, TNF-α and IFN-γ on growth inhibition and stimulation of ALPase in mouse calvarial osteoblast cells. In contrast, IL-1β, TNF-α, and IFN-γ exerted growth-inhibiting effects on mouse calvarial osteoblast cells which were partly NO-dependent. The results suggest that NO may act predominantly as a modulator of cytokine-induced effects on mouse calvarial osteoblast cells and TGF-β is a negative regulator of the NO production stimulated by IL-1β, TNF-α and IFN-γ.     

N-糖基化位点突变的人IFN-λ1在毕赤酵母中的表达、纯化及表征

IFN-λ1是Ⅲ型干扰素家族的一个成员,具有与Ⅰ型干扰素相似的功能。此前,我们已经从毕赤酵母表达获得了可溶性重组人干扰素-λ1。然而,毕赤酵母表达中的高糖基化带来了免疫原性,影响了蛋白质的生产纯化效率。为了克服这个缺点,文中构建了一种干扰素突变体 (rhIFN-λ1-Nm),定点突变潜在糖基化位点。AOX1启动子与α因子信号序列存在的情况下,用甲醇诱导成功地实现了rhIFN-λ1-Nm在毕赤酵母GS115胞外分泌表达。对rhIFN-λ1-Nm进行纯化,获得了纯度>98%的产品,并对糖化水平、分子量、二级结构、N末端序列等理化性质和生物活性进行了研究。研究结果表明,rhIFN-λ1-Nm糖基化水平明显降低,蛋白质生产纯化收率显著提高,而对结构和生物活性无影响;糖基化位点突变rhIFN-λ1可以被开发为IFN-λ1的替代品,有望发展成为未来的生物免疫制剂。     

Analysis of Antarctic proteobacteria by PCR fingerprinting and screening for antimicrobial secondary metabolites

Fifty-seven proteobacterium species were successfully isolated from soils of Barrientos Island of the Antarctic using 11 different isolation media. Analysis of 16S rDNA sequencing of these isolates showed that they belonged to eight different genera, namely Bradyrhizobium, Sphingomonas, Methylobacterium, Caulobacter, Paracoccus, Ralstonia, Rhizobium, and Staphylococcus. All isolates were studied for capability of producing antimicrobial and antifungal secondary metabolites using high-throughput screening models. Approximately 23 (13/57) and 2% (1/57) of isolates inhibited growth of Candida albicans ATCC 10231(T) and Staphylococcus aureus ATCC 51650(T), respectively. These results indicated that proteobacterium species isolates from Antarctic could serve as potential source of useful bioactive metabolites. Enterobacterial repetitive intergenic consensus (ERIC)-PCR fingerprinting produced nine clusters and 13 single isolates, with a high D value of 0.9248. RAPD fingerprinting produced six clusters and 13 single isolates, with a relatively low D value of 0.7776. ERIC-PCR analysis proved to have better discrimination capability than RAPD analysis and generated better clustering for all proteobacterium species isolates. We conclude that ERIC-PCR is a robust, reliable and rapid molecular typing method for discriminating different genera of proteobacteria.     

杉木连栽土壤对其幼树生长的影响

在会同林区采用３种不同连栽杉木次数的土壤,进行杉木幼树盆栽试验．结果表明,杉木连栽不利其幼树生长．连裁使幼树高生长下降３７—４０％,基径下降１９—２８％,冠幅下降２１—２９％,总生物量减少４５—５０％．杉木连栽还造成土壤养分递减,即腐殖质减少７—２８％,速效养分下降２３—２８％,土壤微生物数量和活性也大大降低．因此,杉木纯林连栽经营方式应尽快改变．     

云南虫生真菌粉棒束孢遗传分化研究

对云南粉棒束孢8个当地居群和蝙蝠蛾拟青霉2个当地居群进行ITS测序和RAPD扩增分析,结合Gen Bank中相关序列,对粉棒束孢开展遗传多样性、居群遗传结构及其种内分化研究。共获得大范围内地理距离远的6个居群共97条粉棒束孢ITS序列,共有33种单倍型,单倍型多样性Hd=0.546和总核苷酸多样性Pi=0.00276,显示粉棒束孢在物种水平上遗传多样性较低。云南粉棒束孢共37条序列,有14种单倍型(10种为云南特有),具有较高单倍型多样性和核苷酸多样性(Hd=0.659,Pi=0.00274);单倍型聚类和网状分支分析表明云南粉棒束孢单倍型类型丰富,遗传多样性高,暗示云南为粉棒束孢多样性分布中心之一。ITS序列分析表明,云南当地居群间遗传分化系数Fst=51.95%;RAPD分析表明,居群间遗传分化系数Gst=0.5547,基因流Nm=0.4014;说明云南当地居群粉棒束孢分化剧烈。居群遗传距离与地理距离相关性研究表明,粉棒束孢居群遗传距离与地理距离无明显相关。中性检验和失配分析表明粉棒束孢经历过近期居群扩张。结合单倍型聚类和网状分支分析,表明Hap 19为扩张建群单倍型,但原始祖先单倍型(Hap 1)依然是粉棒束孢居群中最优势单倍型(频率为48.45%),表明粉棒束孢并不存在明显的因地理原因造成的生殖隔离。值得重视的是,通过ITS单倍型和RAPD分析,支持将蝙蝠蛾拟青霉作为粉棒束孢异名处理。