芒颖大麦草对菱镁矿粉尘污染的生态适应性

采用盆栽试验,向土壤表面投加不同量(0、1％、5％、10％、15％、20％、30％)的菱镁矿粉尘,研究土壤理化性质和芒颖大麦草对镁的耐性.结果表明:菱镁矿粉尘施加到土壤表面时,可快速形成结皮.当菱镁粉尘比例超过20％时,土壤理化性质发生明显变化,表现为pH显著升高,电导率逐渐降低,有机质含量先降低后升高;芒颖大麦草的叶绿素含量随着镁粉尘含量的增加呈现先增加后降低的趋势,而可溶性蛋白含量随着镁粉尘含量的增加呈现先增加后降低再升高的趋势;芒颖大麦草具有较强的耐镁特性,土壤中镁浓度达到4.61 g·kg-1时,芒颖大麦草仍生长良好.芒颖大麦草适宜作为菱镁矿区撂荒地生态恢复的植物种.     

Surface Display of Human Serum Albumin on Bacillus subtilis Spores for Oral Administration

Human serum albumin (HSA) is the major protein component of human plasma. To date, HSA for clinical uses is mostly produced by fractionation of human whole blood, which is accompanied by a lot of limitations. To obtain long-term bioactive albumin, we used hsa as a foreign gene and constructed a recombinant plasmid pJS700-HSA which carries a recombinant gene cotC-hsa under the control of cotC promoter. Plasmid pJS700-HSA was transformed into Bacillus subtilis by double cross-over and an amylase inactivated mutant was produced. After induction of spore formation, western blot and fluorescence immunoassay were used to monitor HSA surface expression on spores. We estimated that HSA displayed on the spore accounted for 0.135 % of the total spore proteins and about 0.023 fg HSA were exposed on the surface of each spore. Oral administration to mice with spores displaying HSA implied that the recombinant spores may have potential ability to increase the serum albumin level in vivo due to the resistant characters of spores.     

鲫鱼PKZ Zα结构域与d(GC)、d(TA)重组质粒的结合

Zα是能够特异性识别并结合左旋DNA(Z-DNA)的蛋白结构域,首先在人ADAR1中鉴定,随后又在ZBP-1(DLM-1)和E3L等蛋白质中发现了该结构域．鲫鱼PKZ是首次报道的具有Zα结构域的鱼类eIF2α激酶．为深入了解鲫鱼PKZ Zα的功能,原核表达并亲和层析纯化了3种多肽,即野生型PZα(Zα1Zα2)、替换型P(Zα1)2(Zα1Zα1)和点突变型（PZαK34A、PZαS35A、PZαR39A、PZαP57A）．同时,构建了含有d(GC)6、d(GC)13、d(TA)13特殊插入序列的3种重组质粒,用于体外模拟Z-DNA．凝胶阻滞实验分析了3种多肽分别与重组质粒的亲和性结果表明,PZα和P(Zα1)2能够与d(GC)重组质粒结合,并且随着多肽含量的增加,阻滞效应越明显．与野生型PZα相比,替换型P(Zα1)2结合d(GC)重组质粒的能力更强PZα和P(Zα1)2还能微弱地与d(TA)13重组质粒结合．点突变型多肽都不能与重组质粒结合,暗示鲫鱼PKZ Zα结构域中这4个氨基酸残基在结合核酸分子的过程中非常关键．该文结果有利于进一步揭示鱼类PKZ Zα结构域与Z-DNA结合的分子机理．     

Rapamycin attenuates BAFF‐extended proliferation and survival via disruption of mTORC1/2 signaling in normal and neoplastic B‐lymphoid cells

B cell activating factor from the TNF family (BAFF) stimulates B‐cell proliferation and survival, but excessive BAFF promotes the development of aggressive B cells leading to malignant and autoimmune diseases. Recently, we have reported that rapamycin, a macrocyclic lactone, attenuates human soluble BAFF (hsBAFF)‐stimulated B‐cell proliferation/survival by suppressing mTOR‐mediated PP2A‐Erk1/2 signaling pathway. Here, we show that the inhibitory effect of rapamycin on hsBAFF‐promoted B cell proliferation/survival is also related to blocking hsBAFF‐stimulated phosphorylation of Akt, S6K1, and 4E‐BP1, as well as expression of survivin in normal and B‐lymphoid (Raji and Daudi) cells. It appeared that both mTORC1 and mTORC2 were involved in the inhibitory activity of rapamycin, as silencing raptor or rictor enhanced rapamycin's suppression of hsBAFF‐induced survivin expression and proliferation/viability in B cells. Also, PP242, an mTORC1/2 kinase inhibitor, repressed survivin expression, and cell proliferation/viability more potently than rapamycin (mTORC1 inhibitor) in B cells in response to hsBAFF. Of interest, ectopic expression of constitutively active Akt (myr‐Akt) or constitutively active S6K1 (S6K1‐ca), or downregulation of 4E‐BP1 conferred resistance to rapamycin's attenuation of hsBAFF‐induced survivin expression and B‐cell proliferation/viability, whereas overexpression of dominant negative Akt (dn‐Akt) or constitutively hypophosphorylated 4E‐BP1 (4EBP1‐5A), or downregulation of S6K1, or co‐treatment with Akt inhibitor potentiated the inhibitory effects of rapamycin. The findings indicate that rapamycin attenuates excessive hsBAFF‐induced cell proliferation/survival via blocking mTORC1/2 signaling in normal and neoplastic B‐lymphoid cells. Our data underscore that rapamycin may be a potential agent for preventing excessive BAFF‐evoked aggressive B‐cell malignancies and autoimmune diseases.     

芽孢杆菌B3的鉴定及其对常见污染真菌的拮抗作用

从平菇废弃培养料中分离获得一株细菌B3,通过对其进行形态学、培养特征比较研究和16SrDNA序列分析,鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。在与常见的三种食用菌污染真菌脉孢菌(Neurospora sp.)、木霉(Trichoderma sp.)及鬼伞(Coprinus sp.)分别进行对峙培养时,都有明显的抑菌作用,形成的抑菌带分别为0.38cm、0.57cm及0.56cm,而与平菇(Pleurotus ostreatus)、鸡腿菇(Coprinus comatus)及草菇(Volvariella volvacea)分别进行对峙培养时,除对草菇有明显的抑制作用外,对平菇和鸡腿菇的抑制作用很小。在混接B3菌株麸皮菌剂栽培料培养基上,B3菌株对三种污染真菌的抑制作用都很明显;可抑制木霉分生孢子形成、脉孢菌分生孢子萌发及鬼伞菌丝扩展;但不抑制平菇菌丝的生长。     

Responses of two kidney bean (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis>) cultivars to the combined stress of sulfur deficiency and cadmium toxicity

Plants suffer from combined stress of sulfur deficiency and cadmium toxicity in some agricultural lands. However, little is known about the reaction in plants, such as responses in antioxidant enzymes and non-protein thiol compounds, to such combined stress. Therefore, in this study, four treatments, S-sufficiency (T_S?Cd), S-deficiency (T_?S?Cd), Cd stress (T_S+Cd) and combined stress of S-deficiency and Cd stress (T_?S+Cd), were set up to investigate (1) the effects of sulfur deficiency or sulfur sufficiency on Cd toxicity to kidney bean cultivar seedlings and the related mechanisms, and (2) the responses of two kidney bean cultivars to combined stress of S-deficiency and Cd-tolerance. The results showed significant increases in hydrogen peroxide (H₂O₂) and malondialdehyde contents and significant increases in antioxidant enzyme (superoxide dismutase, catalase, peroxidase, and glutathione S-transferase) activities and non-protein thiol compounds (non-protein thiols, reduced glutathione, phytochelatins) synthesis in the plants in T_S+Cd and T_?S+Cd. On the tissue level, higher proportion of Cd was found to be immobilized/deposited in roots, while on the sub-cell level, higher proportion of Cd was located in cell walls and vacuole fractions with lower in cell organelles. Taken together, the results indicated that Cd detoxification was achieved by the two kidney bean cultivars through antioxidant enzyme activation, non-protein thiol compound synthesis and sub-cellular compartmentalization. In addition, the results indicated that sufficient S supply helped to relieve Cd toxicity, which is of special significance for remediation or utilization of Cd-contaminated soils as S is a plant essential nutrient.     

人参茎叶皂甙对高胆固醇饮食大鼠再灌注性心律失常和脂质过氧化的影响(英文)

研究人参茎叶皂甙(GSL)对高胆固醇饮食大鼠心肌再灌注性心律失常(RPA_r)和脂质过氧化的影响。方法:将胆固醇乳剂用灌胃法饲养大鼠14d,建立高脂血症模型,各组大鼠进行心肌缺血再灌注实验,观察高脂血症和GSL对大鼠心肌缺血再灌注2h后血丙二醇(MDA),超氧化物歧化酶(SOD)和一氧化氮(NO)水平的影响和对再灌注性心律失常发生率的影响。结果显示:(1)用胆固醇乳剂饲养大鼠14d,成功建立高脂血症模型。同时给予GSL14d有明显降脂作用。(2)高脂血症状态下,心肌缺血再灌注2h后,血MDA升高(p<0.01),SOD降低(p<0.01)和NO(p<0.05)降低,再灌注10min内RPAr的发生率增高。(3)GSL组再灌注后2h的血MDA降低,而SOD和NO水平显著升高;使RPAr发生率大为降低,无VF发生。实验显示高脂血症加重心肌缺血再灌注损伤和提高RPAr发生率及动物死亡率,GSL可减少高脂饮食大鼠脂质过氧化和诱导体内NO生成而减轻缺血再灌注心肌损伤,降低缺血再灌注性心律失常发生率。     

β-谷甾醇烟酸酯的制备

采用酯化反应,将烟酰氯和β-谷甾醇合成了β-谷甾醇烟酸酯,并用红外光谱和质谱对其进行了分析。结果表明,酯化反应的最优工艺条件为mol(β-甾醇):mol(烟酰氯):mol(吡啶)= 1:3:5;反应温度91℃;反应时间6 h;用95%的乙醇进行重结晶,产率可达到75%以上;红外光谱和质谱分析表明合成产物为β-谷甾醇烟酸酯。     

喀斯特关键带植被时空变化及其驱动因素

中国南方喀斯特地区广泛面临着生态问题,植被的保护与恢复倍受关注,对这一区域植被覆盖的进行监测和预测是非常必要的。以MODIS-NDVI为数据源,分析2000—2016年间,研究区不同地质背景,多种土地覆被类型的NDVI时空变化特征及驱动因素。结果表明:(1)从2000—2016年间,研究区植被覆盖整体呈增长趋势;其中喀斯特区域增长情况略优于非喀斯特区域。植被覆盖在空间上呈现东高西低;其中林地的NDVI值最高,耕地次之,依次草地,居民用地,水域,未利用地最低;在林地和耕地中,非喀斯特区域的NDVI值比喀斯特高,其余的土地覆被类型中都比喀斯特区域低。(2)研究区植被覆盖改善的地区占60.19%,退化地区占17.06%;草地,耕地区改善明显,退化主要在水域和建设用地; Hurst指数显示在研究区持续性改善的NDVI大于持续性退化;相比非喀斯特区域,喀斯特区域改善及持续性改善情况更佳。(3)整体而言,海拔对NDVI的空间分布影响力最大,温度次之,依次为降雨,夜间灯光指数;相比而言,非喀斯特区域NDVI空间分布更易受地形因子影响;喀斯特区域NDVI空间分布更易受气候差异及人类活动影响。(4)研究区分别有49%,45%,61%的NDVI与气温,降雨,日照的相关系数通过a=0.05的显著性检验;相比非喀斯特而言,喀斯特区域植被生长更易受气候变化的影响。