热带地区植物内生真菌生物多样性研究进展

植物内生真菌是指在其生活史的一定或全部阶段生活于健康植物体内部的真菌。内生真菌具有重要的生物学和生态学作用。简要介绍了热带地区植物内生真菌研究概况、资源多样性、寄主选择,并对热带内生真菌生物多样性的发展前景作了分析。     

模拟酸雨伤害的棉花子叶圆片电鲜质外渗率测定方法的探讨

设计了在酸雨悬浮培养胁迫条件下,用紫外光吸收法测定棉花子叶圆片电鲜质外渗率的程序和计算电解质外渗率的方法。这一程序和方法与前人报道的有所不同,据此而取得的实验结果,则更能真实地反映植物在逆境胁迫下所导致的电解质外渗的实际过程。     

哈茨木霉C184菌株对喀麦隆香蕉及大蕉根部病原菌的体外拮抗作用(英文)

体外测定了新近分离自喀麦隆香蕉及大蕉田间的哈茨木霉(Trichoderma harzianum)菌株C 184对香蕉和大蕉根部病原菌柱枝孢(Cylindrocladium pteridis)及茄镰孢(Fusarium solani),尖镰孢(Fusarium oxysporum)和曲霉 (Aspergillus sp.) 的拮抗作用. 在对峙培养中上述病原菌菌丝生长均受到明显抑制;在赛咯酚分层培养中木霉菌株对上述病原菌菌丝生长的抑制率为67%～88%;木霉菌株培养滤液对上述病原菌菌丝生长的抑制率为52%～87% .电镜下观察到木霉菌株对柱枝孢及镰孢霉的寄生过程,认为这可能是主要拮抗机制之一; 此外木霉菌株在液体培养中产生的抗生素及细胞壁降解酶也可能是抑制病原菌菌丝生长的主要原因.     

萤光假单胞菌根部定殖对水培系统中香石竹生长的影响

 用筛选的萤光假单胞细菌(fluorescent Pseudomonas spp.)菌株WCS X.13,WCS417和WCS 358处理栽培于水培系统中不同香石竹栽培品种的根部,试验结果表明,在通气的三角烧瓶培养中,香石竹品种Pallas经WCS X.13菌株处理后根长、根重显著高于对照,植株鲜重相对增长率高于对照40%;经WCS417菌株处理根长高于对照,香石竹品种Lena经WCS 417菌株处理植株鲜重相对增长率高于对照32%,在营养膜培养中,在人工接种病原菌Fusarium oxysporum f.sp.dianthi的条件下,中抗品种Pallas经试验菌株处理根部6周以后,植株(根上部)鲜重均高于对照,表现促进植株生长的趋势。     

Arabidopsis H+-PPase AVP1 regulates auxin-mediated organ development

The transport of auxin controls developmental events in plants. Here, we report that in addition to maintaining vacuolar pH, the H+-pyrophosphatase, AVP1, controls auxin transport and consequently auxin-dependent development. AVP1 overexpression results in increased cell division at the onset of organ formation, hyperplasia, and increased auxin transport. In contrast, avp1-1 null mutants have severely disrupted root and shoot development and reduced auxin transport. Changes in the expression of AVP1 affect the distribution and abundance of the P-adenosine triphosphatase and Pinformed 1 auxin efflux facilitator, two proteins implicated in auxin distribution. Thus, AVP1 facilitates the auxin fluxes that regulate organogenesis.     

Systemic leukocyte-directed siRNA delivery revealing cyclin D1 as an anti-inflammatory target

Cyclin D1 (CyD1) is a pivotal cell cycle-regulatory molecule and a well-studied therapeutic target for cancer. Although CyD1 is also strongly up-regulated at sites of inflammation, its exact roles in this context remain uncharacterized. To address this question, we developed a strategy for selectively silencing CyD1 in leukocytes in vivo. Targeted stabilized nanoparticles (tsNPs) were loaded with CyD1-small interfering RNA (siRNA). Antibodies to beta(7) integrin (beta(7) I) were then used to target specific leukocyte subsets involved in gut inflammation. Systemic application of beta(7) I-tsNPs silenced CyD1 in leukocytes and reversed experimentally induced colitis in mice by suppressing leukocyte proliferation and T helper cell 1 cytokine expression. This study reveals CyD1 to be a potential anti-inflammatory target, and suggests that the application of similar modes of targeting by siRNA may be feasible in other therapeutic settings.     

易变链霉菌TRM 45540四氢嘧啶合成相关基因的克隆

为了探索嗜盐放线菌对高盐环境的适应机理,以分离于罗布泊易变链霉菌TRM 45540为材料,利用分子克隆技术,构建四氢嘧啶异源生物合成工程菌(以E.coli为宿主),对ectA、ectB、ectC与ectABC基因进行异源表达,分析异源宿主菌的耐盐能力。结果表明:TRM 45540四氢嘧啶合成相关基因ectA为474bp,预测编码蛋白为19ku;ectB为1 272bp,预测编码蛋白为44.6ku;ectC为399bp,预测编码蛋白为19ku;全长基因ectABC为2 403bp,并且携带有ectABC基因工程菌的耐盐能力显著提高。