南亚热带3种阔叶树种人工幼龄纯林及其混交林碳贮量比较

如何通过优化造林模式来提高人工林生态系统碳贮量已受到广泛关注。以南亚热带8年生格木(Erythrophleum fordii)纯林(PE)、红锥(Castanopsis hystrix)纯林(PC)、米老排(Mytilaria laosensis)纯林(PM)及格木×红锥×米老排混交林(MECM)生态系统为研究对象,对其碳贮量及其分配特征进行了比较研究。结果表明:格木、红锥和米老排不同器官平均碳含量分别为512.4—561.7 g/kg,474.2—553.4 g/kg和512.8—556.3 g/kg。相同树种不同器官之间碳含量差异显著(P0.05)。各器官碳含量的平均值大小顺序为格木(539.3 g/kg)米老排(532.7 g/kg)红锥(515.3 g/kg)。不同林分间,灌木层、草本层和凋落物层碳含量均以米老排纯林最高,混交林(MECM)居次,红锥纯林和格木纯林最低;不同林分之间的土壤碳含量差异显著(P0.05),0—10cm,10—30cm,30—50cm和50—100cm土壤碳含量均以米老排纯林最高,红锥纯林居次,格木纯林和混交林(MECM)土壤碳含量最低。生态系统碳贮量大小顺序为米老排(308.0 t/hm2)混交林(182.8 t/hm2)红锥纯林(180.2 t/hm2)格木纯林(135.2 t/hm2),相同组分不同林分间以及相同林分的不同组分间均存在显著差异(P0.05),但混交林与红锥纯林间碳贮量总量无显著差异(P0.05)。造林模式对人工林碳贮量及其分配有显著影响,营建混交林有利于红锥和格木地上碳的累积,不利于土壤碳的固定,而营建纯林既有利于米老排生物量碳的吸收,也有利于土壤碳的固定。因而,对碳汇林造林模式的选择,应根据树种固碳特性而定。     

假单胞菌Pseudomonas fluorescens Pf0-1中转录调控因子SpfB负调控DNA磷硫酰化修饰

[目的]DNA磷硫酰化修饰是DNA骨架上非桥接的氧原子以序列选择性和R-构型被硫取代的一种新型DNA修饰。目前,磷硫酰化修饰在多种细菌、古生菌以及人类致病菌中多有发现,但其分子调控机制尚不清楚。为了全面解析磷硫酰化修饰的调控机制,本文选择荧光假单胞菌Pf0-1为研究对象,开展了其DNA磷硫酰化修饰的调控机制研究。[方法]首先,构建了spfB基因缺失和回补菌株,使用碘能特异性断裂磷硫酰化修饰DNA的方法,研究了该基因缺失对修饰表型的影响。利用cDNA在相邻同方向的基因间隔区进行PCR,确定了磷硫酰化修饰基因簇spfBCDE内的共转录单元。通过荧光定量RT-PCR,分析了spfB基因缺失突变株中磷硫酰化修饰基因的转录量。利用异源表达并纯化得到的重组蛋白SpfB进行了体外功能研究。通过EMSA实验,验证了SpfB蛋白具有与spfB启动子序列结合活性。通过DNase I footprinting实验,精确定位了SpfB蛋白与DNA结合序列。[结果]spfB基因的缺失加剧了磷硫酰化修饰DNA断裂所致电泳条带弥散的表型,spfB基因的回补能够恢复该表型,证明spfB基因负调控磷硫酰化修饰。鉴定了spf基因簇中只含有1个共转录单元,且该共转录单元在△spfB突变株中转录水平明显上升。通过EMSA和DNase I footprint实验,检测了SpfB蛋白与磷硫酰化修饰基因spfBCDE的启动子区域5''-TGTTTGT-3''相结合。[结论]SpfB作为转录调控因子负调控磷硫酰化修饰基因spfBCDE的表达,为解析磷硫酰化修饰的调控机制和全面理解基因组上的部分修饰特征奠定了基础。     

Taxonomy on crane flies in family Tipulidae and Limoniidae (Diptera: Tipuloidea) from Yaoluoping National Nature Reserve,Anhui, China

The paper reports 13 species from Yaoluoping National Nature Reserve,Anhui,China,including a new species and a new subspecies,Tipula (Emodotipula) alexanderi Men,sp.nov.and Nephrotoma impigra anqingensis Men,subsp.nov.The female of Libnotes (Libnotes) pseudonohirai Men,2015 is described and illustrated for the first time.The males of Holorusia henana Yang,1999 and Tipula (Vestiplex)jiangi Yang & Yang,1991 are redescribed and illustrated with new morphological characters.A key to all species is provided.     

地塞米松与硫酸镁对大鼠小肠缺血再灌注损伤的作用及机制

目的研究地塞米松和硫酸镁对大鼠小肠缺血再灌注（I/R）损伤的保护作用,并初步探讨其机制。方法制作小肠I/R模型,实验分为假手术阴性对照组、I/R组、硫酸镁治疗组、地塞米松治疗组、地塞米松和硫酸镁联合治疗组,比较五组血浆二胺氧化酶（DAO）、丙二醛（MDA）的含量,同时比较小肠的病理切片观察治疗效果。结果①I/R组小肠组织病理变化明显,血浆DAO、MDA比假手术阴性对照组显著升高;②硫酸镁治疗组和地塞米松治疗组小肠病理变化减轻,血浆DAO、MDA比I/R组显著降低,且两组无显著差别;③硫酸镁和地塞米松合用组的血浆MDA比I/R组显著升高,但是小肠病理变化和I/R组相比无明显区别,血浆DAO也和I/R组无明显差别。结论硫酸镁,地塞米松分别对大鼠小肠缺血再灌注有保护作用而二者合用却无明显的保护作用。     

带内含子卡那霉素抗性基因双元载体构建及烟草转化

农杆菌介导法是植物基因转化的常用方法,然而由于筛选培养基中常用的抗生素头孢霉素和羧苄青霉素具有类植物激素活性,影响外植体的再生和转化频率。将一个植物的内含子插入卡那霉素抗性基因编码区的N端,合成了一个带内含子的卡那霉素抗性基因。构建带该基因的植物双元表达栽体pYP1202并转化烟草,受侵外植体在含卡那霉素50～200mg/L的选择培养基中抗性芽分化频率不受卡那霉素浓度影响,然而具有GUS活性的转化子占分化芽的比例却随着卡那霉素浓度的增加而升高。当培养基中加入500mg/L羧苄青霉素后受侵外植体产生的抗性芽频率比单一的卡那霉素筛选提高近1倍,高达91.4％,然而具GUS活性的转化子占抗性芽的比例仅有26.7％,在200m/L的卡那霉素筛选下,比例升至93.3％。用带内含子卡那霉素抗性基因构建的植物表达载体转化植物可以减少假抗性芽的产生。     

Population control of the yellow‐spined bamboo locust,Ceracris kiangsu,using urine‐borne chemical baits in bamboo forest

The yellow‐spined bamboo locust, Ceracris kiangsu Tsai (Orthoptera: Oedipodidae), is a notorious defoliator of bamboos in China. In commercial bamboo forests, spraying insecticides to control C. kiangsu is neither convenient nor economic, therefore environmentally acceptable and cost‐effective methods are needed. Ceracris kiangsu adults are known to aggregate and gnaw at human urine‐contaminated materials; NaCl is a strong phagostimulant and NH₄HCO₃ is an attractant/arrestant. In the present paper, we found that foam plastic containers containing a blend of 0.03% bisultap, 3% NaCl, 3% NH₄HCO₃, and 0.1% Triton X‐100 (tetrad bait) had a powerful attracticidal effect and could kill a great number of especially female C. kiangsu adults, comparable to those containing a mixture of 0.03% bisultap and 5‐day‐incubated urine. In a field trial, the tetrad bait killed approximately 80% of females and about 9% of males in the treated plots after daily application for five consecutive days. The corrected average reduction rate was 48.2%. Moreover, the sex ratio was decreased from 1.18 before the trial to 0.25 after the experiment in the treated plots. These results indicated that there is the potential to develop a trap using NaCl as a phagostimulant and NH₄HCO₃ as an attractant that can be used for C. kiangsu control.     

Identification of tumor metastasisrelated gene TMSG-1 by mRNA differential display

To investigate genes involved in cancer metastasis, mRNA differential display was used to compare the levels of gene expression of two cancer sublines derived from prostate carcinoma cell PC-3M that had different metastatic potentials. The differentially expressed genes were confirmed by Northern blot, and sequenced. The full-length cDNA of a tumor metastasis suppressor gene (TMSG-1) was obtained by using EST assembling and verified by RT-PCR and sequencing. The results showed that expression levels of TMSG-1 were lower in the highly metastatic cell line 1E8, compared with the non-metastatic cell line 2B4. The difference was significant. Full-length cDNA of TMSG-1 was about 2 kb, containing an open reading frame that encoded a protein of 230 amino acids. GenBank Blastn showed no marked homology with known genes. The functional prediction of amino acids sequence encoded by TMSG-1 gene indicated TMSG-1 protein was transmembrane protein, with 3 transmembrane domains, 3 putative protein kinase phosphorylatio     

两种野生花卉的扦插繁殖研究

开展野生花卉车轮梅(Raphiolepis indica)和赤楠(Syzygium buxifolium)扦插试验,结果表明:车轮梅硬枝扦插需一定浓度的外源激素方能生根;对激素浓度大小不敏感;总体上NAA组合生根质量优于IBA组合。综合不同处理生根率、根数和不定根根长3个指标,以800 mg/L NAA或800 mg/L IBA作为车轮梅生产上扦插的激素种类和浓度。赤楠生根率较低,最高扦插率达66.7%,生根时间长,约需45 d始生根。综合生根率、不定根根数和不定根根长3个生根指标,试验的4种激素均能较好促进赤楠生根,200×根太阳在生根率和根数上效果最好,生产上可用200×根太阳浸泡2 h,也可用50-100 mg/L NAA或100-400 mg/L IBA浸泡2 h后进行扦插。     

不同ES细胞系体定量神经分化的比较

利用视黄酸（RA）诱导小鼠胚胎干细胞通过悬浮类胚培养体外定量分化为神经样细胞,结果显示能够进行种系嵌合的MESPU22细胞系与不能进行种系统嵌合的MESPU13细胞系的体外神经分化比例在统计学上没有明显差异,此结果对于人的胚胎干细胞全能性的鉴定和检测有重要启示。     

核桃属部分种的小孢子发生及核型研究

本试验采用常规压片法,观察了核桃属(Juglans L.)四个种花粉母细胞(PMC)的减数分裂过程和花粉形态,检测了两个种的花粉生活力,分析研究了七个种的核型。结果表明,普通核桃(J.regia)核桃楸(J.mandskurica Maxim.)和黑核桃(J.nigra L.)的PMC减数分裂基本正常,但河北核桃PMC的减数分裂过程都极不正常,供试的七个种,除普通核桃为2C核型外,其余均为2B核型,仅黑核桃一种带有随体染色体。根据核型特点把七个种分成三组,并探讨了组间与组内种间的亲缘演化关系。作者认为,河北核桃应为一种独立的种,核桃科在系统发育上可能来源于染色体基数为8的两群)不同植物。