Hyperthermia-induced apoptosis and the inhibition of DNA laddering by zinc supplementation and withdrawal of calcium and magnesium in suspension culture of tobacco cells

In the present paper we report examination of stereotypic hallmarks of apoptosis in heat-treated tobacco cells. Hyperthermia (44 °C, 4 h) caused apoptosis in 53.6% of cells when assayed 24 h after heat treatment. The induction of apoptosis by heat treatment was confirmed by flow cytometric assay. Cytological observations revealed condensation of the cytoplasm and nucleus, as well as nuclear collapse. DNA ladders were observed in DNA extracted from heat-treated cells, whereas DNA from control cells remained undegraded. The terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay revealed that 51.8% of the heat-treated cells (44 °C, 4 h) show positive reaction after a 24-h recovery. When cells were cultured in a medium supplemented with 0.4–5.0 mM ZnSO₄, internucleosomal DNA fragmentation induced by heat shock was completely negated. Strikingly, when cells were cultured in Ca²⁺ and/or Mg²⁺ free medium for 44 h followed by heat treatment, DNA laddering was not observed. The results suggest hyperthermia-induced apoptosis and a correlation between the regula tion of endonucleases and heat shock signal in apoptotic tobacco cells. Received 17 September 1998; received after revision 4 January 1999; accepted 4 January 1999     

四川攀枝花烟区湿润育苗基质配比研究

通过将草炭和黄泥土按比例混合作为育苗基质,以探究适合烟草湿润育苗的基质配比.结果表明,草炭与黄泥土按7:3比例混配制作育苗基质时所育烟苗综合素质最高,株高、茎围适中,根系发达,根系活力强.     

关于苦荬菜、华蒲公英和罗布麻对烟草解毒效应的研究

苦荬菜(Ixeris denticculata)、华蒲公英(Taraxacum cinicum kitag)和罗布麻(Apocynum,renetum)是三种富含白色乳汁的野生植物.分别将其嫩茎熬制得到煮出液.用来给注射不同剂量烟草煮出液的青蛙解毒.结果表明.苦荬菜和华蒲公英对烟草煮出液具有解毒作用.而罗布麻无解毒作用.     

普格县烟叶生产可持续发展规划

《规划》以普格县生态条件和社会经济条件为基础，以建立基本烟田和基本烟田保护制度为核心，明确了普格县优质烤烟的种植区域，制定了2005年至2008年近4年内烟叶生产的目标、方向及保障措施。     

生物钾肥对改良烟草品质提高烟草产量的效果

本文总结了七年来生物钾肥（硅酸盐菌剂）在七个烟草生产省份中试验、示范、推广的结果，证明施用这种生物肥料不但可以改善烟叶品质、提高烟叶产量、改良烟田土壤、减少化学钾肥施用量、减少烟叶病害，而且施用方法简便又不破坏生态环境。推广这项技术可带来可观的经济效益和生态效益。     

烟草科技新动态

本文分析综述了１９９０年－１９９４年来自１３个国家和地区的烟草研究专利１１９件，指出了美、日研究特点及我国存在之不足，需要的倒是其跨地区、跨行业、优势互补的大联合、大协作。     

Tobacco curly shoot virus isolated in Yunnan is a distinct species of Begomovirus

Virus isolate Y1 was obtained from tobacco showing curly shoot symptoms in Baoshan, Yunnan Province. Whitefly transmission test and virion morphology observation showed that it is a begomovirus. In reactions with 14 monoclonal antibodies raised against begomoviruses, Y1 was readily differentiated from begomoviruses reported in China, Pakistan and India. The complete nucleotide sequence of DNA-A was determined, it contains 2746 nucleotides, with two ORFs in virion-sense DNA and four ORFs in complementary-sense DNA. Comparisons with total DNA-A, intergenic region and deduced amino acid sequences of individual ORFs showed that Yl is a distinct Begomovirus species, for which the name Tobacco curly shoot virus (TCSV) is proposed. The total DNA-A of TCSV is most closely related to that of Tomato leaf curl virus from India (85% sequence identity). In contrast, the deduced coat protein of TCSV is most like that of Cotton leaf curl virus 72b isolate from Pakistan (98% amino acid sequence identity).     

茉莉酸甲酯对烟草幼苗可溶性物质含量的影响及与诱导抗病的关系

用1mg.mL^-1的茉莉酸甲酯（methyl jasmonate,简称Me-Ja）处理4叶期烟草（Nicotiana talacumL.）幼苗,然后接种黄瓜花叶病毒（Cucumlez mosaic virus,CMV）,一定时间后分析可溶性、还原糖、游离氨基酸含量变化,实验结果表明Me-Ja处理降低了3个品种幼苗的蛋白质、氨基酸和还原糖含量,但Me-Ja处理后接种CMV对3个品种烟草幼苗的蛋白质、氨基酸和还原糖含量的影响结果不一致,有的降低,有的升高,因此蛋白质、氨基酸和还原糖与抗病性的关系可能不密切。     

基于模糊控制的滚筒烘丝机的烟丝烘干控制系统

该系统以DSP单片机为核心处理器,利用中频感应加热技术,提高热源的加热效率.通过频率自动跟踪技术,使加热效率达到最佳.利用PWM技术实时调整加热温度.同时利用模糊控制算法,将加热温度、送风风量、风向导向综合控制,实现控制进入滚筒内热风的风量、温度,进而实现控制烟丝烘干效果的目的,使得烟丝烘干过程可控性好,烘干效率高.     

Identification of a novel DNA molecule associated with Tobacco leaf curl virus

A circular DNA molecule, designated as DNAβ, was identified in tobacco plants infected with Tobacco leaf curl virus (TLCV) isolates Y5 and Y8 by PCR using primers based on the conserved region of the two reported DNAβsequences of whitefly-transmitted geminiviruses (WTGs). The complete nucleotide sequences of DNAβof Y5 and Y8 (TLCV DNAβ) were determined. Y5 DNAβcomprises 1333 nucleotides encoding 8 predicted ORFs with 4 ORFs in virion-sense DNA and 4 ORFs in complementary-sense DNA; Y8 DNAβconsists of 1338 nucleotides encoding 7 predicted ORFs with 4 ORFs in virion-sense DNA and 3 ORFs in complementary-sense DNA. TLCV DNAβhas little sequence homology to DNA-A of TLCV, except that it shares conserved TAATATTAC loop sequence with TLCV DNA-A. Sequence comparison showed that Y5 DNAβshared 85% sequence homology with Y8 DNAβ, and both Y5 DNAβand Y8 DNAβhad relatively low sequence identity (51%-65%) with the reported DNAβmolecules associated with Ageratum yellow vein virus and Cotton leaf curl virus. The immunotrapping PCR and whitefly transmission tests showed that DNAβmolecule could be encapsidated in virus particle and transmitted by Bemisia tabaci. This is the first report of DNAβassociated with WTGs in China.