Strain improvement of <Emphasis Type="Italic">Trichoderma viride</Emphasis> for increased cellulase production by irradiation of electron and <Superscript>12</Superscript>C<Superscript>6+</Superscript>-ion beams

Objectives

To improve cellulase production and activity, Trichoderma viride GSICC 62010 was subjected to mutation involving irradiation with an electron beam and subsequently with a ¹²C⁶⁺-ion beam.

Results

Mutant CIT 626 was the most promising cellulase producer after preliminary and secondary screening. Soluble protein production and cellulase activities were increased mutifold. The optimum temperature, pH and culture time for the maximum cellulase production of the selected mutant were 35 °C, pH 5 and 6 days. The highest cellulase production was obtained using wheat bran. The prepared cellulases from T. viride CIT 626 had twice the hydrolytic performance with sawdust (83 %) than that from the parent strain (42.5 %). Furthermore, molecular studies demonstrated that there were some key mutation sites suggesting that some amino acid changes in the protein caused by base mutations had led to the enhanced cellulase production and activity.

Conclusions

Mutagenesis with electron and ¹²C⁶⁺-ion beams could be developed as an effective tool for improvement of cellulase producing strains.

     

Clearance of adenovirus by Kupffer cells is mediated by scavenger receptors, natural antibodies, and complement

Kupffer cells (KCs) rapidly remove intravenously injected adenovirus (Ad) vectors from the circulation. A better understanding of the mechanisms involved could suggest strategies to improve Ad gene delivery by suppressing or evading KC uptake. We recently showed that clearance of Ad type 5 vectors by KCs does not involve the interaction of Ad with the well-established Ad receptors, namely, integrins or the coxsackievirus and Ad receptor (J. S. Smith, Z. Xu, J. Tian, S. C. Stevenson, and A. P. Byrnes, Hum. Gene Ther. 19:547-554, 2008). In the current study, we systematically quantified the contributions of various receptors and plasma proteins to the clearance of Ad by KCs. We found that scavenger receptors are a predominant mechanism for the clearance of Ad by KCs. In addition, we found that Ad is opsonized by natural immunoglobulin M antibodies and complement and that these opsonins play a contributory role in the clearance of Ad by KCs. We also examined additional mechanisms that have been postulated to be involved in the clearance of Ad, including the binding of Ad to platelets and vitamin K-dependent coagulation factors, but we found that neither of these were required for the clearance of Ad by KCs.     

Ultra‐Lightweight 3D Carbon Current Collectors: Constructing All‐Carbon Electrodes for Stable and High Energy Density Dual‐Ion Batteries

Dual‐ion batteries (DIBs) attract great interest because they allow two types of ions for reversibly intercalating into electrodes, resulting in various advantages. However, there are three critical problems using graphite‐based cathodes, namely, low active material proportion in the electrodes, current collector corrosion, and massive cathode variation. For addressing these problems, an ultra‐lightweight 3D carbon current collector (CCC) is developed to fabricate all‐carbon electrodes as both cathodes and anodes. Compared with the conventional DIBs using Al and Cu foils as current collectors, the DIBs with 3D CCC of electrically conductive pathways and sufficient ionic diffusion channels deliver enhanced specific capacity stabilized around 140 and 120 mAh g^?1 at 0.5 and 1C, respectively. The electrochemically inert 3D CCC could essentially promote the energy density when calculating the entire electrode mass, along with long‐life cycle stability of 1000 cycles at 5C and no electrochemical corrosion on either anodes or cathodes. With an in situ optical microscope, the cathode expansion is found to massively reduce because the porous 3D CCC could effectively alleviate the huge volume. The results suggest a novel strategy for achieving low‐cost and high energy density DIBs with both mechanically and electrochemically stable features.     

农业科研试验数据分析系统－LNT

分析了农业科研试验统计的基本方法,简述了统计软件包－ＬＮＴ的程序总控流程及主要功能,阐述了软件包的主要特点,提出了将农业统计分为方差分析、相关通径、回归分析、遗传分析和数据管理五大类２４小类的思想,编写了１２１种统计方法,运行于各种机型的集成软件包－ＬＮＴ。     

Network succession reveals the importance of competition in response to emulsified vegetable oil amendment for uranium bioremediation

Discerning network interactions among different species/populations in microbial communities has evoked substantial interests in recent years, but little information is available about temporal dynamics of microbial network interactions in response to environmental perturbations. Here, we modified the random matrix theory‐based network approach to discern network succession in groundwater microbial communities in response to emulsified vegetable oil (EVO) amendment for uranium bioremediation. Groundwater microbial communities from one control and seven monitor wells were analysed with a functional gene array (GeoChip 3.0), and functional molecular ecological networks (fMENs) at different time points were reconstructed. Our results showed that the network interactions were dramatically altered by EVO amendment. Dynamic and resilient succession was evident: fairly simple at the initial stage (Day 0), increasingly complex at the middle period (Days 4, 17, 31), most complex at Day 80, and then decreasingly complex at a later stage (140–269 days). Unlike previous studies in other habitats, negative interactions predominated in a time‐series fMEN, suggesting strong competition among different microbial species in the groundwater systems after EVO injection. Particularly, several keystone sulfate‐reducing bacteria showed strong negative interactions with their network neighbours. These results provide mechanistic understanding of the decreased phylogenetic diversity during environmental perturbations.     

小兴安岭不同耐荫性树种枝叶性状变异及权衡

随着植株生长,不同耐荫性树种枝叶性状对资源的响应策略存在差异。探究不同耐荫性树种在不同径级间枝叶性状变异及其相关关系,对理解植物功能性状种内和种间变异以及植物对资源的响应策略具有重要意义。以黑龙江凉水国家级自然保护区阔叶红松（Pinus koraiensis）林中不同径级（小树、中等树和大树）的喜光树种（白桦Betula platyphylla、枫桦Betula costata）和耐荫树种（春榆Ulmus japonica、紫椴Tilia amurensis、色木槭Acer mono）为研究对象,测定其出叶强度、枝横截面积、枝干重、单叶面积、总叶面积、总叶干重共6个枝叶性状。利用单因素方差（LSD）分析检验不同耐荫性树种在不同径级间其枝、叶性状是否存在显著差异;以标准化主轴估计（SMA）对不同耐荫性树种枝叶性状间相关关系进行分析。结果表明：除枝干重外,耐荫树种枝叶性状均大于喜光树种;不同耐荫性树种大树枝横截面积均最大,中等树叶面积均最小;喜光树种不同径级间枝干重、总叶干重和出叶强度无显著差异,而耐荫树种均存在显著差异。随径级增大,不同耐荫性树种枝横截面积与叶面积均呈正异速生长关系,且除耐荫树种枝横截面积与单叶面积外,均存在共同斜率;不同耐荫性树种出叶强度与单叶面积存在共同斜率为-0.51和0.47,小树和中等树枝横截面积与总叶面积和总叶干重的异速生长指数均与1存在显著差异,而大树与1无显著差异。结果表明：不同耐荫性树种在不同径级间对资源的获取策略存在差异,不同耐荫性树种小树阶段均表现出资源获取策略,大树阶段则表现出资源保守型策略。与耐荫树种相比,喜光树种表现为快速生长策略,而随着径级增大不同耐荫性树种这种差异逐渐消失,本研究结果为森林演替过程中种内和种间的相互作用提供了一个新的视角。     

西双版纳热带次生植被不同抚育方式下的群落学分析

对西双版纳勐仑地区的热带雨林刀耕火种撩荒后在不同抚育方式下恢复起来的次生植被进行了群落数量特征、种群年龄结构及立木材积与蓄积量的比较分析,并探讨了热带次生植被的抚育管理方式及途径。结果表明,在900m²的固定样地上,天然更新的次生群落计有维管束植物73种,分属于36科59属。其科、属、种组成比经人工抚育的次生群落分别高24.14%、43.90%和75.56%,其结构层次也较复杂,但材积量仅为后者的1/4.