红松松子壳多糖的单糖组成及结构初步分析

采用膜分离技术对红松松子壳热水提取物进行分离纯化,经脱蛋白、脱色后得到总多糖PPSPⅠ-b,通过DEAE-52离子交换纤维素柱层析分离得到纯化组分PPSPⅠ-1,采用气相色谱和红外光谱分析了多糖样品的单糖组成及结构特征。气相色谱分析表明:PPSPⅠ-b主要由鼠李糖、阿拉伯糖、木糖、甘露糖、葡萄糖和半乳糖组成,其物质的量比为3.40∶1.40∶0.79∶7.82∶10.67∶18.35;PPSPⅠ-1主要由鼠李糖、阿拉伯糖、甘露糖、葡萄糖和半乳糖组成,其物质的量比为0.96∶2.30∶2.97∶10.60∶6.91。红外光谱分析表明,PPSPⅠ-1具有多糖的特征吸收峰。     

油松籽油酸洗缓蚀剂的合成与应用

以油松籽油、二乙烯三胺、氯化苄为原料,合成了咪唑啉季铵盐缓蚀剂Y-1,用失重法、极化曲线法评价了Y-1及其与硫脲复配后的新型缓蚀剂的缓蚀性能.结果表明:缓蚀剂Y-1在盐酸体系中对A20钢有很好的缓蚀效果,由Y-1和硫脲复配的新型缓蚀剂在柠檬酸体系中对A20钢的缓蚀效率在99.65％以上,并且二者都具有很好的热稳定性;缓...     

贮藏条件对红皮云杉种鳞多酚含量及抗氧化功能的影响

本试验以红皮云杉种鳞为原料,研究pH值、光照、温度、金属离子及添加剂等贮藏条件对红皮云杉种鳞多酚含量及抗氧化功能的影响。试验结果显示,4℃低温和避光条件下,红皮云杉种鳞多酚最稳定,保留率依次为93.08%、87.23%,DPPH自由基清除率依次为80.65%、82.16%,总还原力OD值依次为0.854、0.798。酸性条件对红皮云杉种鳞多酚含量影响较小,碱性条件破坏红皮云杉种鳞多酚,pH 2条件下多酚保留率、DPPH·清除率和总还原力OD值分别是pH 10的2.21倍、4.56倍、2.78倍。添加钠、钾、钙离子对红皮云杉种鳞多酚含量和抗氧化功能无显著影响,而铜、锌、铁离子能够显著降低多酚含量和抗氧化功能。浓度高于30%的蔗糖和0.01%苯甲酸钠能够延缓红皮云杉种鳞多酚的降解,对抗氧化稳定性无显著影响。本试验在降解试验的基础上探究贮藏条件对红皮云杉种鳞多酚抗氧化功能的影响,将为多酚的应用开创新的前景。     

Divergence and conservation of SUP2(SUP35) gene of yeasts Pichia pinus and Saccharomyces cerevisiae

SUP2(SUP35) is an omnipotent suppressor gene, coding for an EF-1α-like protein factor, intimately involved in the control of translational accuracy in yeast Saccharomyces cerevisiae. In the present study a SUP2 gene analogue from yeast Pichia pinus was isolated by complementation of the temperature-sensitive sup2 mutation of S. cerevisiae. The nucleotide sequence of the SUP2 gene of P. pinus codes for a protein of 82·4 kDa, exceeding the Sup2 protein of S. cerevisiae by 6 kDa. Like the SUP2 gene product of S. cerevisiae, the Sup2 protein of P. pinus represents a fusion of a unique N-terminal part of a region homologous to EF-1α. The comparison of amino acid sequences of the Sup2 proteins reveals high conservations (76%) of the C-terminal region and low conservation (36%) of the N-terminal part where, in addition, the homologous correspondence is ambiguous. Proteins related to the Sup2 of S. cerevisiae where found in P. pinus and some other yeast species by the immunoblotting technique. The relation between the evolutionary conservation of different regions of the Sup2 protein and their functional significance is discussed.     

Multiplicity of mechanisms of carbon catabolite repression involved in the synthesis of alcohol oxidase in the methylotrophic yeast Pichia pinus

The effect of various carbon compounds on the synthesis of alcohol oxidase in a medium with methanol was studied in the wild type strain of Pichia pinus as well as in gcr1 and ecr1 mutants defective in glucose and ethanol repression of methanol metabolic enzymes, respectively. Compounds repressing the synthesis of alcohol oxidase in the wild type strain were divided into four groups. Repression of alcohol oxidase by compounds of the first group (glucose, fructose, mannose, galactose, L -sorbose and xylose) was impaired only in the gcr1 mutant and that by compounds of the second group (ethanol, acetate, 2-oxoglutarate and erythritol) only in the ecr1 mutant. Repression by compounds of the third group (malate, dihydroxyacetone) was not impaired in both these regulatory mutants and that by compounds of the fourth group (succinate, fumarate, L -arabinose, sorbitol, salicin, xylitol and cellobiose) was partially reduced in both gcr1 and ecr1 strains. Mutation gcr1 causes a significant decrease in phosphofructokinase activity. It also led to a six- to seven-fold increase in intracellular pools of glucose-6-phosphate and fructose-6-phosphate and to a two-fold decrase in the intracellular pool of fructose-1,6-bisphosphate. In ecr1 strains, a decrese in 2-oxoglutarate dehydrogenase activity accompanied by an increae in activities of NAD- and NADP-dependent isocitrate dehydrogenases and NAD- and NADP-dependent glutamate dehydrogenases was demonstrated. The intracellular pool of 2-oxoglutarate was increased 2·5-fold in ecr1 strains. Genes GCR1 and ECR1 are not linked. The mechanisms of catabolite repression of alcohol oxidase in methylotrophic yeasts are discussed.     

Mutants of the methylotrophic yeast Pichia pinus defective in C2 metabolism

A collection of mutants of Pichia pinus which are unable to grow on ethanol but retain the ability to grow on glucose and methanol, was obtained. Genetic and biochemical analysis of these strains revealed mutations in seven nuclear genes affecting activities of isocitrate lyase (icl1), malate synthase (mls1), phosphoenolpyruvate carboxykinase (pck1), ‘malic’ enzyme (mdd1) and acetyl-CoA synthetase (acs1, acs2 and acs3). All mutations except acs1-acs3 have no effect on the activities of other enzymes involved in C₂ metabolism. Mutations acs1, acs2 and acs3 have a pleiotropic action, leading to partial reduction in activities of isocitrate lyase and malate synthase. Ethanol-induced repression of the synthesis of the methanol oxidative enzymes, alcohol oxidase and catalase, is not impaired in these seven mutant classes. On the other hand, C₂ compound-induced inactivation of alcohol oxidase and catalase is impaired in mutants acs1, acs2, acs3 and icl1. It was suggested that glyoxylate and acetate (or acetate precursors) act as low molecular weight effectors, ‘switching on’ inactivation and repression, respectively, of alcohol oxidase and catalase in the medium containing ethanol or acetate.     

大气污染影响下森林绿叶产量变化评价

全球生态学的定量基础方法之一是森林测量学,它正在不断促进全球生态计划和国际森林监测技术水平的发展.然而,传统的方法也带来了一定的偏差,例如:在欧洲,由于大气污染的影响,当森林生物量增长时,也会引起森林郁闭度的降低.文章通过利用生物或生态基础理论与技术,尝试建立解决这类矛盾的方法.通过将通道输送模型理论与树木同化分配的概念相结合,即利用树木同化物质在树木木质部和韧皮部传输的特性进行测量,与树木同化产生的绿叶生物量进行分离,得到显示大气污染对区域性环境影响的信息.新方法以这些信息为基础建立的阚值水平标准,可以对大气污染状况进行指示.并利用森林生物产量的损失情况,对大气污染破坏林地生产量进行了评价.研究表明,该方法可以用于立法标准和大气污染控制信贷体系的构建,促使自然保护组织监管企业环境污染和安全生产带来的危害.     

Isolation and preliminary characterization of Pichia pinus mutants insensitive to glucose repression

A new method for the isolation of glucose repression-insensitive mutants in the methylotrophic yeast Pichia pinus was developed. The method is based on screening of small suspension samples derived from 2-deoxyglucose-resistant colonies for alcohol oxidase activity. Alcohol oxidase activity was evaluated by determination of formaldehyde excreted by cells. Mutants with glucose non-repressible alcohol oxidase and catalase synthesis were obtained. All mutants grew poorly on D -xylose compared to the wild type, whereas growth on L -arabinose was similar to the wild type. Changes in the glucose transport system were suggested to be responsible for altered growth characteristics and defective glucose repression.     

云南云景林纸股份有限公司 原料林基地规划建设的基本情况

本文介绍了云南云景林纸股份有限公司（思茅纸厂）原料林基地规划建设概况,总结了多年思茅松栽培经验,拟订了思茅松造纸原料林人工营造技术规程。     

南方红壤区马尾松林下水土流失与降雨量关系研究

为了更好地研究马尾松林水土流失规律,从水土流失主要控制因子——降雨因子出发,通过对红壤侵蚀区不同林下配置模式马尾松林径流试验小区2009—2011年的产流、产沙与降雨量的关系研究。得到如下结论：①各小区的产流量和产沙量均与降雨量呈显著性相关,回归模型主要以一元二次回归最优,个别小区以幂函数和对数函数最优,其中以马尾松地表裸露小区模拟方程可决系数最大;②各雨型在同一郁闭度条件下,除去郁闭度为0％的小区外,各小区基本满足乔＋地表裸露〉乔＋百喜草〉乔＋胡枝子,伴随着降雨量的增加,各小区的径流系数总体上呈增加的趋势,尤其在暴雨和大暴雨以上的雨型更加明显;③产沙方面,各雨型条件下,除去郁闭度为O％的小区和个别郁闭度为24％的小区外,基本上满足乔＋地表裸露〉乔＋胡枝子〉乔＋百喜草。