河北省豆科植物根瘤菌资源的初步调查研究

通过对河北省全境豆科植物的结瘤和固氮状况进行调查 ,共采集到 2 4属 5 3种豆科植物的根瘤样品 2 3 5份 ,98.1的被调查豆科植物可自然结瘤 ,96.2的自然瘤可测到固氮酶活性 .其中海边香豌豆 (L athyrus maritimus)、野百合 (Crotalaria sessilif lora)、阴山胡枝子 (L athyrusinschanica)、山岩黄耆 (H edysarum alpinum)、辽西扁苜蓿 (Melilotus ruthenicus)的结瘤固氮情况为首次报道 .     

Extreme sexual dimorphism in a Miocene hominoid

Some Miocene hominoids may have been extremely sexually dimorphic for body size, inferred from the apparent dimorphism of dental and gnathic remains. But this has never been demonstrated convincingly for any fossil species because of small sample sizes, uncertainties about the number of species in most fossil samples, and the inability to reliably sex individual specimens. Here we demonstrate a case of extreme dental dimorphism, and presumed body-size dimorphism, in a Miocene hominoid sample in which these limitations have been overcome. Lufengpithecus lufengensis from the late Miocene site of Lufeng, China, was more dimorphic than the most dimorphic living hominoid, the orangutan, and may have been more dimorphic than any living anthropoid.     

Positive interactions among alpine plants increase with stress

Plants can have positive effects on each other. For example, the accumulation of nutrients, provision of shade, amelioration of disturbance, or protection from herbivores by some species can enhance the performance of neighbouring species. Thus the notion that the distributions and abundances of plant species are independent of other species may be inadequate as a theoretical underpinning for understanding species coexistence and diversity. But there have been no large-scale experiments designed to examine the generality of positive interactions in plant communities and their importance relative to competition. Here we show that the biomass, growth and reproduction of alpine plant species are higher when other plants are nearby. In an experiment conducted in subalpine and alpine plant communities with 115 species in 11 different mountain ranges, we find that competition generally, but not exclusively, dominates interactions at lower elevations where conditions are less physically stressful. In contrast, at high elevations where abiotic stress is high the interactions among plants are predominantly positive. Furthermore, across all high and low sites positive interactions are more important at sites with low temperatures in the early summer, but competition prevails at warmer sites.     

不同微生物组合对石油烷烃降解性能的比较分析

以大连石油污染海域的海洋沉积物作为分离样品,以天然海水培养基分离获得13种海洋石油降解微生物,并通过模拟海底低温微氧环境,以原油作为唯一碳源,评价了13种微生物的石油降解性能。GC-MS分析结果表明,随着降解时间的增加,组合G6及其构建菌株P73和P83对烷烃的降解率逐渐升高。对于C>32的长链烷烃部分,尤其对于石油中的难降解组分如姥鲛烷(Pr)和植烷(Ph)的降解,组合G6的降解效果明显优于单菌株。由高效石油降解菌菌株P73和菌株P83构建的组合G6对于石油烷烃中很难降解和风化的长链烷烃具有强大的协同降解作用。     

新型介孔钒氧化物催化剂上丙烷高选择性氧化脱氢制丙烯研究

采用醇溶液浸渍法制备了介孔SBA-15、介孔MCM-41及无定形SiO2三种不同氧化硅载体担载的系列钒氧化物催化剂．活性测试结果表明,SBA-15为载体的钒氧化物催化剂具有优良的丙烷氧化脱氢反应性能．BET、SEM/TEM、UV-Vis DRS,TPR,UV Raman和程序升温吡啶-FTIR结果表明：介孔SBA-15载体较大的比表面积及孔径、对钒氧物种较高的分散能力以及催化剂表面仅存在少量的弱酸性位等特点有利于丙烷的活化及产物丙烯的脱附,使得催化剂在丙烷氧化脱氢反应中显示出高活性和高选择性．     

松材线虫携带细菌的鉴定和毒性研究

从松材线虫病致死的松材木质部和松材线虫体表分离到3个出现频率较高的细菌菌株，菌株Nji、Njt和Njw。经鉴定3种细菌分别为荧光假单胞菌I型（Pseudomonas fluorescens biotype I)荧光假单胞菌Ⅱ型（Pseudomonas fluorescens biotype Ⅱ）和泛菌属某种（Pantoea sp.)。用牛肉膏蛋白胨液体培养基振荡培养细菌，培养液直接处理黑松愈伤组织，测定各细菌的产毒能力。与对照（空白培养液）相比，3种细菌的培养原液都可对黑松愈伤组织产生明显影响，其中菌株Nih和菌株Njt可以在2d内使愈伤组织明显变色，菌株Njw处理变色较慢。表明菌株Nij和Njt培养液内有大量致萎毒性物质存在。     

盐胁迫下水稻和黑麦幼苗蛋白质组份的变化

耐盐的779水稻幼苗中,盐胁迫后诱导出66kD/P15\5和26kD/p16.0的特异蛋白组份,并有多种蛋白质组份消失和含量减少现象,而在盐敏感的早花2号水稻中,虽然也有少数蛋白质组份被诱导产生,但没有检测到66kD和26kD两种蛋白质组份,并且双向SDS－PAGE谱型相对稳定,一般耐盐的黑麦幼苗中经盐胁迫后也诱导出26kD蛋白组份,因此,66kD,26kD两种蛋白组份可能与耐盐性有关。     

不同木材种类炭化率的研究

根据木材本身的材性缺陷和木材加工厂的废料存量情况,选择了岑树、山毛榉、花旗松、橡木、白杨和云杉作为研究对象,研究了这些木材在实验室热解条件下炭产品的生产能力.在390～672 ℃范围内,共做28次分组热解试验,试验时间为2 h,每组10个试件;390～440 ℃范围内,共做8次分组热解试验,试验时间为1 h,每组10个试件.分别测试了试件在热解试验前后的质量损失和体积的变化,特别是试件在热解实验后的炭化率.结果表明:所有树种的试件在500℃时完全炭化,试件的相对质量损失约为25%,试件的三维收缩约为30%(T)、25%(R)、20%(L).不同树种试件的炭化率是相同的,木材的炭化率和树种无关,木材热解炭化后的理论孔隙率经验公式为ε=100-30ρ01,通过此公式可研究木材的初始干燥密度预测其生产炭产品的性能.     

粤东北镉污灌区人群血镉含量与SOD,GSH-P_x及MDA的关系

镉污灌区大米和人尿中的镉含量明显大于非污灌区(P<0.001),而镉污灌区人群中血镉含量同过氧化物岐化酶、谷胱甘败过氧化酶、丙二醛等生化指标的差异也有明显意义(P<0.01),血硒含量的差异(P>0.05)则不及血锌含量的差异(P<0.01)。     

Retrograde transport of endocytosed Shiga toxin to the endoplasmic reticulum.

Shiga toxin and some other protein toxins that act on targets in the cytosol have previously been shown to enter the trans-Golgi network. Transport by this route may be necessary for translocation of the toxin to the cytosol and for intoxication, but it is not known whether the enzymatically active part of the toxins actually enters the cytosol from the trans-Golgi network. It has been suggested that such toxins are transported in a retrograde manner to the endoplasmic reticulum and that translocation occurs in this organelle, but retrograde transport of endocytosed material beyond the trans-Golgi network has never been demonstrated. Here we show that in butyric acid-treated A431 cells endocytosed Shiga toxin is not only transported to the trans-Golgi network, but also to all Golgi stacks, to the endoplasmic reticulum and to the nuclear envelope. Furthermore, butyric acid sensitizes the cells to Shiga toxin, which is consistent with the possibility that retrograde transport is required for translocation of the toxin to the cytosol.