降低卷丹百合组培褐变技术研究

以卷丹百合Lilium lancifolium鳞片为外植体,采用1/2MS+0.8 mg·L~(-1) 6-BA+0.2 mg·L~(-1) NAA为基本培养基,研究不同消毒时间的外植体消毒效果,探讨聚乙烯吡咯烷酮(PVP)、抗坏血酸(V?)、活性炭(AC)以及光、暗两种培养条件对卷丹百合组织培养过程中褐变的影响。结果表明,用75%酒精消毒30 s、0.1%HgCl_2消毒10 min、2%NaClO消毒6 min的消毒效果最好,污染率为33.33%,成活率和诱导率均为66.67%。在培养基中加入PVP、V?、AC和暗培养均能减轻褐变的发生,其中以4.5 mg·L~(-1) PVP处理对卷丹百合褐变的抑制效果最好,外植体褐变率最低为30%,愈伤组织诱导率为70%。     

巢湖流域生态安全评价研究

目前,巢湖流域的生态安全问题非常突出,已严重影响流域社会经济的可持续发展。基于巢湖流域社会经济、水体环境质量及水生生态系统的数据资料,应用驱动力-压力-状态-影响-响应(DPSIR)模型,提出了基于水环境和水生态的巢湖流域生态安全评价框架模型和指标体系,并采用熵权物元模糊评价法进行巢湖流域生态安全评价研究。研究结果表明,2003和2007年巢湖流域整体处于生态安全中度风险状态,水体环境质量的变化和水生生态系统的演替将严重威胁巢湖流域的生态安全,水体中的TP浓度、NH-N浓度以及TN浓度是决定巢湖流域生态安全的最关键因子。     

离子注入选育高产壮观链霉菌的研究

利用离子注入选育高产壮观链霉菌。壮观链霉菌1043为一壮观霉素生产菌种,通过实验建立了离子注入选育壮观链霉菌。其效价较出发菌株提高了102.3%。     

达斡尔族青少年体型的Heath—Carter人体测量法研究

运用Heath-Carter人体测量法对1759例（男872,女887）6－19岁达斡尔族青少年体型进行了研究。结果表明：（1）男生6－8岁各组为均衡的中胚层体型,9－12岁各组为三胚层中间型体型,13－17岁各组为中胚层－外胚怪均衡型体型。女生7－12岁各组为三胚层中间型体型,13－14岁各组为均衡的内胚层体型,15－19岁各组为偏中胚层的内胚层体型。（2）男女生6－9岁中胚层体型比例最高,10－12岁外胚层体型比例最高。男生13－16岁仍为外胚层体型比较最高。女生13－15岁、16－19岁均为内胚层体型比例最高。（3）达斡尔族男女生体型与蒙古族体型接近。     

钉螺在枫杨防护林和芦林分布密度的比较研究

通过对长江外滩枫杨防护林和芦林钉螺分布密度的调查比较,结果表明：枫杨林钉螺分布密度明显低于芦林;两种群落钉螺分布密度不同程度受长江洪泛的影响;两种群落中４种抑制钉螺的植物对钉螺分布密度的影响相似。     

Plant Regeneration from Protoplasts of Corn(Zea mays L.)

Maize embryogenic calli induced from pollen were subcultured for one and one half years on N, basic medium supplemented with 2 mg/1 kinetin, 1 mg/l 6-benzyl-aminopurine, 0.3 mg/l 2,4-D, 500 mg/l casein hydrolysate and 250 mg/l glutamine. These embryogenic calli were used for protoplast isolation. Protoplasts were cultured on Z2 medium (Table 1) which is composed of rice protoplast culture basic medium 1 supplemented with 0.2 mg/l kinetin, 0.1 mg/l 6-benzyl-aminopurine, 0.5 mg/l 2,4-D, 200 mg/l casein hydrolysate, 100 mg/l glutamine and 2% coconut milk. The first division of regenerated cell occurred after 4-6 days in culture. After 3 weeks later, small calli could be seen with naked eyes. At this moment, addition of the same Z2 medium with decreased osmoticum twice for the protoplast culture is necessary. Regenerated calli, 2–4 mm in diameter, were transferred in succession on differentiation medium Z3 and Z4 for organogenesis. Embryogenesis and plant regeneration could occur simultaneously on Z4 differentiation medium. It seems that except the cultural conditions genotype and using of embryogenic materials are the two key factors for plant regeneration of maize protoplast and the former may be the critical one.     

土壤微生物数量对模拟氮沉降增加的早期响应

通过以南亚热带森林三种主要树种即荷木、锥栗和黄果厚壳桂为主的苗圃试验地的苗圃控制实验,初步探讨土壤微生物数量对模拟氮沉降增加的响应。结果表明,施氮增加对土壤微生物数量的影响根据类群和氮处理水平不同而异。总的来说,施氮增加对土壤微生物数量具有促进作用,这种促进作用对放线菌数量仅在一定(中氮)处理水平以下,超过此水平施氮增加则表现为抑制作用,而施氮对真菌数量则始终表现为抑制作用,尤其以中N处理水平的抑制作用最强。但目前细菌仍占微生物总量的绝对优势,放线菌次之,真菌则占微生物总量的比例最小。分析结果还表明,有效氮与放线菌、有效氮与细菌数量变化呈显著相关关系。     

广州大夫山雨季林内外空气TSP和PM2.5浓度及水溶性离子特征

采用平行同步采样法,于2012年雨季,对广州市大夫山森林公园林内外空气的总悬浮颗粒物(TSP)和细颗粒物(PM_2.5)样品进行了24 h收集,测定了TSP和PM_2.5的质量浓度并分析了样品中水溶性无机离子成分。结果表明:林内外PM_2.5的质量浓度平均值分别为(40.18±10.47)和(55.79±13.01) g/cm³;林内外TSP的质量浓度分别为(101.32 ± 33.19)和(116.61±35.36) g/cm³。林内与林外比,PM_2.5和TSP平均质量浓度都显著减少(P < 0.05),表明森林能显著改善空气环境质量。TSP和PM_2.5中SO₄^2-、Na⁺、NH₄⁺和NO₃^-为水溶性无机离子主要成分,占总离子质量的80%以上,林外这些离子的浓度高于林内(NH₄⁺除外)。这4种离子雨季在空气中的主要存在方式为NaCl、Na₂SO₄、NH₄HSO₄和NH₄NO₃。计算表明,采样期间海盐对大夫山空气TSP和PM_2.5的水溶性组分中Na⁺和Cl^-贡献最大,其它元素主要源自陆地源。林内外TSP和PM_2.5的c(NO₃^-)/c(SO₄^2-)比值在0.3以下,表明固定源是大夫山森林公园空气主要污染贡献者,TSP中c(NO₃^-)/c(SO₄^2-)的比值大于PM_2.5的比值,说明移动源对TSP的贡献大于PM_2.5。     

Improving ethanol and xylitol fermentation at elevated temperature through substitution of xylose reductase in Kluyveromyces marxianus

Thermo-tolerant yeast Kluyveromyces marxianus is able to utilize a wide range of substrates, including xylose; however, the xylose fermentation ability is weak because of the redox imbalance under oxygen-limited conditions. Alleviating the intracellular redox imbalance through engineering the coenzyme specificity of NADPH-preferring xylose reductase (XR) and improving the expression of XR should promote xylose consumption and fermentation. In this study, the native xylose reductase gene (Kmxyl1) of the K. marxianus strain was substituted with XR or its mutant genes from Pichia stipitis (Scheffersomyces stipitis). The ability of the resultant recombinant strains to assimilate xylose to produce xylitol and ethanol at elevated temperature was greatly improved. The strain YZB014 expressing mutant PsXR N272D, which has a higher activity with both NADPH and NADH as the coenzyme, achieved the best results, and produced 3.55 g l^?1 ethanol and 11.32 g l^?1 xylitol—an increase of 12.24- and 2.70-fold in product at 42 °C, respectively. A 3.94-fold increase of xylose consumption was observed compared with the K. marxianus YHJ010 harboring KmXyl1. However, the strain YZB015 expressing a mutant PsXR K21A/N272D, with which co-enzyme preference was completely reversed from NADPH to NADH, failed to ferment due to the low expression. So in order to improve xylose consumption and fermentation in K. marxianus, both higher activity and co-enzyme specificity change are necessary.     

慈菇蛋白酶抑制剂A和B中Trp残基周围构象与酶抑制专一性的关系

通过定点诱变结合荧光光谱学方法研究了慈菇蛋白酶抑制剂A和B(APIA和APIB)Trp残基周围构象与酶抑制专一性之间的关系。研究表明APIB中的两个Trp残基 (93和 12 2位 )所处环境的疏水性要比APIA中的强。Trp定点诱变研究表明 ,在APIB中 ,Trp12 2 周围环境的疏水性要比Trp93 强。用Ser和Leu分别替代 82位Leu和 87位Arg ,使APIB中色氨酸荧光特性变得与APIA的基本相同 ,同时还发现其酶的抑制专一性也变得趋近APIA的 ,暗示Trp周围的构象与酶抑制剂的抑制专一性有关。