Glacier area change and its impact on runoff in the Manas River Basin,Northwest China from 2000 to 2020

Understanding the distribution and dynamics of glaciers is of great significance to the management and allocation of regional water resources and socio-economic development in arid regions of Northwest China.In this study,based on 36 Landsat images,we extracted the glacier boundaries in the Manas River Basin,Northwest China from 2000 to 2020 using eCognition combined with band operation,GIS(geographic information system)spatial overlay techniques,and manual visual interpretation.We further analyzed the distribution and variation characteristics of glacier area,and simulated glacial runoff using a distributed degree-day model to explore the regulation of runoff recharge.The results showed that glacier area in the Manas River Basin as a whole showed a downward trend over the past 21 a,with a decrease of 10.86%and an average change rate of–0.54%/a.With the increase in glacier scale,the number of smaller glaciers decreased exponentially,and the number and area of larger glaciers were relatively stable.Glacier area showed a normal distribution trend of increasing first and then decreasing with elevation.About 97.92%of glaciers were distributed at 3700–4800 m,and 48.11%of glaciers were observed on the northern and northeastern slopes.The retreat rate of glaciers was the fastest(68.82%)at elevations below 3800 m.There was a clear rise in elevation at the end of glaciers.Glaciers at different slope directions showed a rapid melting trend from the western slope to the southern slope then to the northern slope.Glacial runoff in the basin showed a fluctuating upward trend in the past 21 a,with an increase rate of 0.03×10^(8) m^(3)/a.The average annual glacial runoff was 4.80×10^(8) m^(3),of which 33.31%was distributed in the ablation season(June–September).The average annual contribution rate of glacial meltwater to river runoff was 35.40%,and glacial runoff accounted for 45.37%of the total runoff during the ablation season.In addition,precipitation and glacial runoff had complementary regulation patterns for river runoff.The findings can provide a scientific basis for water resource management in the Manas River Basin and other similar arid inland river basins.

产β-mannanase内生菌的诱变育种和酶学特性研究

以实验室筛选的产伊甘露聚糖酶的黄豆内生菌Bacillussubtilis HD-1（54．6U／mL）为出发菌株，分别采用紫外线，硫酸二乙酯，紫外线-光复活和紫外线．硫酸二乙酯对其进行诱变，结果表明，以紫外线-硫酸二乙酯复合诱变效果最好，获得-株高产伊甘露聚糖酶的突变菌株BacillussubtilisLID．20，酶活达89．5u／mL，比出发菌株提高了63．9D／01遗传性能稳定。该伊甘露聚糖酶的最适反应温度和pH分别为50℃和7．0，该酶在50℃以下，pH5．0-8．0之间稳定性较好，属于中性酶。亚铁离子和钴离子对酶有较强的激活作用，相对酶活分别提高了13．2％和31．7％，但锰离子对酶有强烈的抑制作用，相对酶活仅有对照组的55．6％；金属离子钾、钙、钴和钡都能增强酶热稳定性，其中钴离子的增强效果最为明显，残余酶活约是对照组的1．5倍。

内生菌产β-mannanase条件优化及底物特异性研究

以产β-甘露聚糖酶的植物内生菌Bacillus subtilis UD-20为研究对象,通过对产酶条件优化得出最佳产酶方案为:魔芋精粉30 g/L,蛋白胨3 g/L,硝酸铵3 g/L,氯化钙3.0 mmol/L,氯化镁2.0 mmol/L,氯化钡0.2 mmol/L,2%的接种量发酵培养72 h,酶活高达213.6 U/mL,是优化前的2.4倍,通过补料发酵使酶活提高到275.1 U/mL,较补料前提高了34%。另外,静置培养也使酶活得到了很大提高。较低的Km(10.9 mg/mL)和较高Vmax(9 960.2 U/mL)显示该酶的具有较强的底物特异性,以葡甘露聚糖为底物时的酶活高达6 116.6 U/mL,是酶解槐豆胶的22.2倍,酶解瓜尔豆胶的28.2倍。

Molecular Cloning and Characterization of Fruit Softening Related Gene β-Mannanase from Banana Fruit

A 1 250 bp cDNA fragment encoding β-mannanase, named MaMAN, was cloned from banana （Musa spp cv. Baxi） fruit using degenerate primers designed with reference to the conserved nucleic acid sequences of known β-mannanase genes by RT-PCR. Sequence analysis showed that MaMAN cDNA encompassed a 1 085 bp open-reading frame （ORF）, encoding a predicted polypeptide of 395 amino acids. Alignment of the deduced amino acid sequence of MaMAN and other putative β-mannanases showed that MaMAN has an identity of 86, 70, 69, 54, and 57%, respectively, to β-mannanases from tomato, lettuce, arabidopsis, carrot and oryza sativa. The catalytic residues： Asn203, Glu204, Glu318 and the active site residues： Arg86, His277, Tyr279, and Trp360, which were strictly conserved in the glycoside hydrolase family 5 to which all β-mannanases belonged, were found in MaMAN. Semi-quantitative RT-PCR revealed that the level of MaMAN transcript in the pulp increased during banana fruit ripening, suggesting that MaMAN was likely to be involved highly in banana fruit softening.

Preliminary Study on Selection and Identification of a Mannanase-producing Strain and Its Enzymatic Properties

[Objective] This study aimed to identify a maunanase-producing strain isolated from soil. [Method] With kanjac powder as the substrate, a man- nanase-producing dominant strain was iselated from the soil samples collected from Kunyu Mountain by using plate selection method. Sequence analysis of the 16SrDNA fragment of the strain was conducted, and the strain was identified as Bacillus subtilis. Fermentation conditions and enzymatic characteristics were studied preliminarily. [ Result] Experimental result showed that enzyme yield of this strain was different in different medium and in the same medium at different tempera- ture. Enzyme yield of this strain in LB medium was higher when incubated at 27 ℃ than at 30 ℃ ; however, incubation at 30 ℃ was more conducive to the enzyme production than incubation at 27 ℃ in SOC medium. The optimal reaction pH was 7.0 and the optimal reaction temperature was 55 ℃ for enzyme production of this strain. When the temperature was above 55 ℃, enzyme activity declined sharply with the raise of temperature. Under the optimum conditions, enzyme activity could achieve 95.3 U. [ Conclusion] This study provided reference for the industrial application of degradation products of mannan.

Development of two methods for rapid screening of recombinant Pichia pastoris strains with high-level expression of β-mannanase

The yeast Pichia pastoris(P. pastoris) has been used for the expression of heterologous proteins with the significant success. However, it is time-consuming to screen the high expression level of the recombinant P. pastoris directly. Thus, for β-mannanase production, developing the accurate, rapid and inexpensive screening method to substitute random screening is certainly required. A simple method based on the size of hydrolysis hole was described here, but this method was not very accurate that could only be used in preliminary screening. To further improve the accuracy, a micro-plate screening method is established, which appears to be more accurate and effective. The efficiency of this screening method is about 10 times higher than that of the general screening strategy of cultivation in shaking flasks. Two methods presented here can also be used for screening of recombinant Pichia strains with high-level expression of other heterologous protein after modification.

Identification, Cloning and Characterization of Dictyoglomus Turgidum CelA, an Endoglucanase with Cellulase and Mannanase Activity

The discovery of new, highly active, biomass-degrading enzymes is important to the development of a sustainable biofuels industry. Dictyoglomus turgidum, a thermophilic, anaerobic eubacterium that ferments cellulose and produces ethanol and hydrogen, was chosen as a candidate to screen for novel enzymes. A novel thermostable endoglucanase, CelA, was identified and purified during screening of a shotgun library of Dic（yoglomus turgidum and subsequently subcloned and expressed in E. coli. The celA gene coding for a 312 amino acid protein showed low homology to proteins outside the genus Dictoglomi and lacked an apparent signal peptide. CelA had a broad substrate range, possessing both endo and exo activity on soluble and insoluble β-（1,4）-Iinked glucose-containing substrates as well as endo activity on soluble and insoluble β-（1,4）-linked mannose containing substrates. The specific activity of CelA was 226 U/rag using β-glucan, 66 U/mg using glucomannan, and 63 U/mg using CMC as substrates. The high temperature optimum of 70 ℃ to 80 ℃ and wide substrate range of the enzyme might make it an excellent tool for biomass degradation at high temperature.

Characterization of β-1,4-D-mannanase Produced by Bacillus subtilis MSJ-5

Properties of enzyme production of a Bacillus subtitles strain （ MSJ-5 ） isolated from soil were studied in the test. Enzyme production reached the peak when MSJ-5 being cultured in fermentation medium for 32 h. 6-1,4-D-mannanase was the main component of crude enzyme solution, test results showed that the optimal reaction temperature of the enzyme was 50 ℃, the optimum reaction pH was 7.0, and the enzyme was stable when pH was 5.0 -7.0. Hydrolysis test re- suits showed that β-1,4-D-mannanase produced by MSJ-5 had significant viscosity reduction effects on Konjak mannan, and the major hydrolysis product was man- nan oligosaecharide. The results indicated that 6-1,4-D-mannanase produced by B. subtilis MSJ-5 had application potential in feed ingredients and functional oligo- saccharides industry.

嗜酸乳杆菌表达载体的构建及其甘露聚糖酶的表达

为获得产甘露聚糖酶的嗜酸乳杆菌(Lactobacillus acidophilus)菌株,该研究构建甘露聚糖酶表达载体并转化嗜酸乳杆菌,分析重组嗜酸乳杆菌产甘露聚糖酶的酶学性质,并测定重组嗜酸乳杆菌的耐酸性及甘露聚糖酶的抗蛋白酶活性。结果表明,重组嗜酸乳杆菌发酵24 h,其所产甘露聚糖酶活性为353 U/m L。甘露聚糖酶的最适催化pH值为5.5,最适催化温度为55℃。重组嗜酸乳杆菌在pH 2.0~4.5有一定的耐酸性,在pH 2.0条件下2 h的存活率为77.3%。甘露聚糖酶液用胃蛋白酶、胰蛋白酶处理160 min后,甘露聚糖酶的相对酶活分别为65%、28%。表明该甘露聚糖酶具有一定的抗胃蛋白酶和部分抗胰蛋白酶降解能力。

考虑广义储能参与灵活响应的光储氢集站实时能量管理策略

为了促进含氢能源系统中灵活性资源的综合利用,针对光储氢集站对调度指令的响应问题,提出一种考虑广义储能参与灵活响应的光储氢集站实时能量管理策略。对光储氢集站内电池储能、电制氢负荷等广义储能进行精细化建模,在集站模型中引入考虑电-热-流耦合关系的电制氢虚拟储能模型。通过优化集站灵活性资源的出力构建日内-实时两级能量管理策略,在能量管理优化层面满足运行计划要求的同时考虑效益最大化,实现电池储能荷电状态初、末状态优化;对系统功率波动进行实时反馈校正,保证集站内功率平衡。算例仿真结果验证了所提策略在提升运行经济效益、促进可再生能源消纳方面的积极作用。

转β-甘露聚糖酶基因manA小鼠的制备

为了获得β-甘露聚糖酶基因manA的转基因小鼠,从黑曲霉中克隆得到β-甘露聚糖酶基因manA,进行体外表达检测甘露聚糖酶活性后,将此基因插入到含有猪腮腺分泌蛋白(PSP)基因启动子的表达载体pPSPBGPneo中,得到在腮腺组织特异表达β-甘露聚糖酶基因manA的载体pPSP-manA,总长为16.3 kb,将其进行线性化后回收得到高质量DNA片段,通过显微注射得到17只原代小鼠,进行PCR和Southern blot检测发现有6只阳性转基因小鼠,表明转β-甘露聚糖酶基因manA小鼠制备成功。

熔融法皂化EVA接枝MANa离聚物的制备及影响因素的研究

采用熔融法进行乙烯-醋酸乙烯酯共聚物(EVA)与马来酸钠(MANa)的接枝反应,并利用红外光谱对接枝物(EVAL-g-MANa)的结构进行了表征。结果表明,接枝物在1 575cm-1处出现了宽的羧酸盐的C=O特征伸缩振动峰,证明MANa已与EVAL发生接枝反应,生成了离聚物。运用正交设计分析了单体浓度、反应时间、反应温度、转速等因素对EVAL-g-MANa离聚物接枝率的影响,优化了离聚物的制备工艺。

嗜热毛壳菌甘露聚糖酶Ct Man26的性质及其在甘露寡糖制备中的应用

旨在实现嗜热毛壳菌(Chaetomium thermophilum)中的甘露聚糖酶Ct Man26在毕赤酵母(Pichia pastoris)中高效表达,探究重组酶Ct Man26的酶学性质及在甘露寡糖(mannooligosaccharides,MOS)制备中的潜力。甘露聚糖酶Ct Man26共含448个氨基酸,由碳水化合物结合模块CBM35、Linker及GH26家族的催化域模块组成,催化结构域上的Asp-395、Leu-396和CBM35辅助模块上的Leu-100受到多个疏水作用力,并可与Linker上氨基酸形成多个氢键。重组酶Ct Man26经P.pastoris表达后,存在N-糖基化修饰,蛋白表观分子质量约为55 kDa。重组酶Ct Man26的最适温度为55℃,最适pH值为5.0,50、60℃处理1 h后酶活力仍保持在90%以上,在pH 4.0~12.0范围表现出良好的稳定性。以魔芋甘露聚糖为底物时,重组酶Ct Man26的比活力为23.15 U/mg,米氏常数为4.75 mg/mL,最大反应速度为27.17μmol/(min·mg)。重组酶Ct Man26制备的MOS主要为甘露糖(14.2 mg/L)、甘露二糖(20.1 mg/L)、甘露三糖(6.1 mg/L)和甘露四糖(2.5 mg/L)。进一步研究发现,制备的MOS表现出较好的抗氧化能力,当样品质量浓度为2.4 mg/mL时,对1,1-二苯基-2-三硝基苯肼自由基清除率、2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除率、羟自由基清除率以及超氧阴离子自由基清除率分别为(90.80±0.65)%、(80.7±1.07)%、(69.10±1.10)%和(76.7±3.14)%。同时,MOS具有明显的益生元特性,能够抑制大肠杆菌(Escherichia coli)的生长,促进有益菌戊糖片球菌(Pediococcus pentosaceus)和植物乳杆菌(Lactobacillu plantarum)的生长,且随着MOS添加量增加及培养时间的延长越发明显。综上所述,重组甘露聚糖酶Ct Man26具有较好的酶学特性,在MOS的制备中具有潜在的应用价值。

深开挖有限元分析中释放荷载模拟——三种常用方法比较及改进的Mana法

论述深开挖有限元分析中释放荷载的三种模拟方法———Ｍａｎａ法、单元应力内插法和位移法．通过实例对比分析指出：位移法精度最高，但程序处理较繁琐；单元应力内插法计算效果最差，编程也不方便；Ｍａｎａ法概念明确，易于程序处理，但第一级开挖荷载偏大，以致影响以后各级的计算效果．文中对Ｍａｎａ法改进后，计算精度明显提高．

左旋咪唑对MANA诱发大鼠食管癌前病变预防作用的研究

本文旨在研究左旋咪唑(Levamisole)对食管癌的预防作用。食管癌前病变是食管癌发病过程中的必经阶段,防治食管癌前病变是预防食管癌的重要措施。Wistar大鼠82只,用甲基戊基亚硝胺(N—methyi—N—amylnitrosamine,简称MANA)诱发食管上皮增生,经105天实验显示左旋咪唑(每天10mg/kg,6次/周)具有与太洛龙相似的抑制食管癌前病变作用,并降低血清中MANA的含量。但是,左旋咪唑使大鼠体重增加变快,而太洛龙则使之变慢。结果表明左旋咪唑为优。

Crustal structure in northern margin of Tianshan mountains and seismotectonics of the 1906 Manas earthquake

长86 km、南北向横跨乌鲁木齐坳陷的深地震反射剖面,揭示了北天山山前地壳的薄皮构造特征.共深度点叠加剖面的石河子以南部分显示了天山北缘平行山体的第一和第二排背斜构造.与双程时间分别为2.5～3.0s和5.5～6.0s的反射事件对应的滑脱构造,将地壳深部构造与地表逆断裂-褶皱构造联系在一起.玛纳斯断裂以铲形方式向下延伸,在2.5s左右深度归并于第一滑脱面,向南与清水河断裂汇合.在5.5～6.0s深度上为与玛纳斯下背斜相连的主滑脱面.它们最终汇集到准噶尔南缘断裂.石河子以北的坳陷沉积深度达12～14km.沿剖面的莫霍界面深度在准噶尔盆地为45km左右,往南加深至50km.对该区域内的深地震测深剖面和布格重力异常资料的分析结果,与深反射剖面的地壳结构图象具有一致性.深地震反射剖面通过1906年玛纳斯7.7级地震宏观震中区,共深度点叠加剖面用于推断玛纳斯7.7级地震与北天山山前地壳构造之间的关系:玛纳斯地震属于一类“褶皱地震”,其发震构造是由准噶尔南缘断裂、清水河逆冲断裂、滑脱面和玛纳斯浅部断坡组成的断层系.

黑曲霉β-甘露聚糖酶ManA耐热突变体的筛选

为了改造黑曲霉(Aspergillus niger)来源的β-甘露聚糖酶ManA,获得耐热性高的突变体。利用易错聚合酶链式反应(PCR)技术对构建的表达质粒pGAPZαA-manA进行随机突变,将突变文库转化至毕赤酵母(Pichia pastoris)GS115,表达筛选耐热性高的突变体,并进一步对突变位点进行定点突变,筛选其他耐热性高的突变体。结果表明,ManA的H283R与H283K突变体相对于野生型在耐热性方面有显著提升,75℃加热30 min其相对酶活由26.66%分别提升至76.95%和83.57%;在pH 3.0~9.0的条件下,50℃保存24 h,H283K突变体与野生型的相对酶活均在90%以上,H283R突变体在pH 3.0时的相对酶活下降到了84.72%,两个突变体的最适温度、pH及比酶活与野生型没有明显差异。说明β-甘露聚糖酶ManA的283位组氨酸(H283)对其耐热性较为关键,将该位点突变为精氨酸(R)和赖氨酸(K)时,ManA的耐热性得到显著提升。

新疆玛纳斯河流域地下水砷氟碘分布及共富集成因

为了更好地掌握新疆玛纳斯河流域地下水中As、F、I的分布及富集成因,通过相关性分析和地球化学模拟,分析了高As、高F、高I地下水的水化学特征及空间分布状况;结合地质条件和地下水赋存环境进一步阐明地下水As、F和I的来源、迁移与富集的水文地球化学过程.结果表明:地下水砷、氟、碘含量变化范围分别为1.13~41.35µg/L、0.06~8.02mg/L、<0.025~0.249mg/L,地下水As、F、I超标分别为62.9%、45.7%、45.7%,有31.4%的地下水砷氟碘均超标.砷氟碘共富集的地下水主要分布在玛纳斯河流域东部靠近沙漠边缘的平原区,水化学类型主要为HCO_(3)·SO_(4)·Cl-Na型.自山前单一结构潜水区至平原承压水区,地下水As含量沿流向先增大后在沙漠边缘区减小,水平方向上,地下水的淋滤作用导致南部富As岩层中的As向平原承压水区富集,且碱性条件下SO_(4)2-的还原有助于As的解吸附;地下水F含量沿地下水流向逐渐增大,在古尔班通古特沙漠边缘达到2.5mg/L.高HCO_(3)^(-)、高Na^(+)、高pH值的地下水还原环境是F从含水层基质向地下水释放的重要原因;地下水I含量沿地下水流向整体呈上升趋势,在承压水区潜水中主要受蒸发浓缩作用的影响,在承压水中主要受岩石风化作用的影响.砷氟碘共富集地下水主要分布于100~310m的承压水中.在封闭的承压含水层,碱性还原环境下矿物溶解与沉淀和水岩相互作用是地下水砷氟碘共富集的主要机制.

枯草杆菌manA基因的克隆及定点突变

manA是编码β-甘露聚糖酶(β-1,4-mannan mannohydrolase EC3.2.1.78)的基因。将枯草杆菌A33株的manA基因插入到pET-32a载体,并在大肠杆菌BL21(DE3)中实现了异源非融合表达,表达活力为41.58U/mL。为了提高酶的表达活力,当采用PCR介导的定点突变技术将该基因第2号密码子CUU突变为GUU,构建成突变表达载体pET-32a-manA*并转入大肠杆菌BL21(DE3)中表达,目标酶表达活力增加到138.65U/mL。说明当β-甘露聚糖酶N端第二号氨基酸由亮氨酸突变为缬氨酸后,酶在大肠杆菌中的表达活力大大提高。推测是由于突变后的β-甘露聚糖酶在大肠杆菌中的稳定性增强所致。突变表达的β-甘露聚糖酶最适作用温度和pH值并没有发生明显改变。

黑曲霉β-甘露聚糖酶基因manA在PK15细胞中的分泌表达

通过RT-PCR方法,从黑曲霉总RNA中克隆出β-甘露聚糖酶基因manA的成熟肽编码序列。将其与猪腮腺分泌蛋白(parotid secretory protein,PSP)基因的信号肽序列通过重叠延伸PCR方法得到拼接片段,并插入到真核表达载体pcD-NA6.0/HisTMA中,得到重组质粒pcDNA-PSmanA。重组质粒经过PCR、酶切、测序鉴定,证实含有目的片段,且读码框完全正确。在脂质体介导下将pcDNA-PSmanA转染猪肾(PK15)细胞进行分泌表达,通过RT-PCR方法证实其在PK15细胞中表达,并在细胞培养液中检测酶活性得到β-甘露聚糖酶基因酶活性为14.5 IU/mL。