番茄果实乙烯释放量的遗传模型分析

本试验选择2个番茄果实乙烯释放量显著不同的番茄品系,通过P_1、P_2、F_1、F_2、B_1和B_2六世代的分析方法,研究了番茄果实乙烯释放量的遗传规律.结果表明:番茄果实乙烯释放量遗传符合1对负向完全显性主基因+加性-显性多基因模型(D-4),主基因效应在B_1、B_2和F_(23)个世代的遗传率分别为36.33%、44.09%和35.14%,多基因效应在B_1、B_2和F_(23)个世代的遗传率分别为54.73%、40.50%和54.88%.     

核黄素和接种番茄黄化曲叶病毒对番茄叶片防御酶活性的影响

以番茄品种‘1479’为材料,研究了喷施核黄素(Riboflavin)和接种番茄黄化曲叶病毒(TYLCV)对幼苗叶片中过氧化物酶(POD)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)3种防御酶活性的影响。结果显示:(1)核黄素能显著降低番茄植株的番茄黄化曲叶病毒病的病情指数,并以2 mmol/L时诱导效果最佳,诱抗效果最高可达41.91%。(2)2mmol/L核黄素处理后96h内,番茄叶片的POD、PPO和PAL活性显著高于对照。(3)接种TYLCV后,核黄素处理和接种TYLCV处理均可诱导番茄叶片中防御酶活性显著增强。研究表明,核黄素处理可诱导POD、PPO和PAL活性的系统增强与番茄对TYLCV的诱导抗性密切相关。     

番茄脂氧合酶基因的表达和酶活性分析

将番茄脂氧合酶基因Tom loxD克隆至酵母表达载体pPIC9K中,转化毕赤酵母GS115菌株,构建组成型表达Tom loxD的酵母工程菌株。SDS-PAGE和W estern blot分析表明,经甲醇诱导,Tom loxD蛋白在酵母中得到表达,表达的融合蛋白分子量约为103.56 kD,与预测的分子量一致。酶活性分析表明,酵母中表达的Tom loxD蛋白具有脂氧合酶活性。半定量RT-PCR分析表明,Tom loxD基因在番茄中表达受机械损伤的诱导,损伤处理的番茄叶片中脂氧合酶的活性明显增高。说明Tom loxD基因在番茄防御信号中发挥作用。     

Increase of Adenylate Kinase Isozyme 1 Protein During Neuronal Differentiation in Mouse Embryonal Carcinoma P19 Cells and in Rat Brain Primary Cultured Cells

Abstract: Adenylate kinase (AK), which catalyzes the equilibrium reaction among AMP, ADP, and ATP, is considered to participate in the homeostasis of energy metabolism in cells. Among three vertebrate isozymes, AK isozyme 1 (AK1) is present prominently in the cytosol of skeletal muscle and brain. When mouse embryonal carcinoma P19 cells were differentiated by retinoic acid into neural cells, the amount of AK1 protein and enzyme activity increased about fivefold concomitantly with neurofilament (NF). Double-immunofluorescence staining showed that both AK1 and NF were located in neuronal processes as well as the perinuclear regions in neuron-like cells, but not in glia-like cells. The amount of brain-type creatine kinase increased only twofold during P19 differentiation. The AK isozyme 2, which was not detected in adult mouse brain, was found in P19 cells and did not increase during the differentiation. Mitochondrial AK isozyme 3, which uses GTP instead of ATP as a phosphate donor, was increased significantly. Immunohistochemical analysis with the primary cultured cells from rat cerebral cortex showed similar cellular localization of AK1 to those observed with differentiated P19 cells. These results suggest an important role of this enzyme in neuronal functions and in neuronal differentiation.     

Alterations of Antioxidant Enzymes and Oxidative Damage to Macromolecules in Different Organs of Rats During Aging

Oxygen free radicals have been hypothesized to play an important role in the aging process. To investigate the correlation between the oxidative stress and aging, we have determined the levels of oxidative protein damage and lipid peroxidation in the brain and liver, and activities of antioxidant enzymes in the brain, liver, heart, kidney, and serum from the Fisher 344 rats at ages of 1, 6, 12, 18, and 24 months. The results showed that the level of oxidative protein damage (measured as carbonyl content) in the brain and liver was significantly higher in older animals than in young animals. No statistical difference was observed in the lipid peroxidation of the liver and brain between young and old animals. The activities of antioxidant enzymes in most tissues displayed an age-dependent decline. Superoxide dismutases in the heart, kidney, and serum, glutathione peroxidase activities in the serum and kidney, and catalase activities in the brain, liver, and kidney, significantly decreased during aging. Cytochrome c oxidase, an enzyme involved in electron transport in mitochondria, initially increased, but subsequently decreased in the aged brain, whereas no significant alteration was observed in the liver mitochondrial antioxidant enzymes. The present studies suggest that the accumulation of oxidized proteins during aging is most likely to be linked with an age-related decline of antioxidant enzyme activities, whereas lipid peroxidation is less sensitive to predict the aging process.     

H_2O_2和MAPK介导油菜素内酯诱导番茄抗氧化防护酶SOD和CAT的信号途径

本文以番茄为材料,研究H2O2和MAPK在BR诱导的抗氧化防护系统中的作用。结果表明,外源BR提高抗氧化防护酶SOD和CAT活性;而这种诱导机制被H2O2产生抑制剂二苯基碘（DPI）和MEK1/2专一抑制剂PD98059阻断。进一步研究发现：BR能够诱导细胞质外体H2O2的产生,这种诱导被PD98059抑制;BR能够活化一种49kDaMAPK,这种活化被DPI抑制。本研究结果证实细胞质外体H2O2和MAPK候选激酶（49kDaMAPK）信号参与BR诱导的抗氧化防酶途径,且两者之间存在交互作用。     

植物芪类合成途径相关酶、基因和调控机制研究进展

植物芪类化合物,是一类具有抗菌植保作用的次生代谢产物,因具有抑菌、抗氧化、抗肿瘤等多种生物活性而越来越受到重视。本文对植物芪类生物合成途径中涉及到的相关酶、基因和代谢调控机制的研究现状和应用系统生物学研究芪类生物合成途径的相关酶、基因的方法进行综述,并讨论了芪类生物合成相关酶、基因研究的重要意义和应用,以期为调节芪类产量、满足药用保健需求及植物防御、作物品质改良提供帮助。     

番茄COBRA基因克隆、表达模式及生物信息学分析

COBRA作为一种重要的胞外糖基磷脂酰肌醇(GP-I)锚定蛋白,影响植物细胞壁中纤维素含量及细胞的定向伸长。目前已有多个拟南芥、玉米及水稻的COBRA基因的突变体被研究。而有关番茄COBRA基因克隆的研究尚未见报道。本研究利用RT-PCR技术克隆了一个假定编码番茄COBRA蛋白的SlCOBRA基因,并在GenBank注册(JN398667)。序列测定和分析表明,该序列由6个外显子组成,编码444个氨基酸残基;氨基酸序列中存在COBRA蛋白的CCVS保守基序,N端的跨膜信号肽及C-末端的疏水性尾部和GPI锚定ω-位点。系统进化分析表明番茄SlCOBRA与拟南芥AtCOB具有80%氨基酸序列同源性,聚在一个分支上。Real-time PCR分析番茄各个组织中COBRA基因的表达结果表明番茄COBRA为组成型表达,在营养器官(根、茎、叶)中的表达量高于花和果实,尤其在成熟的果实中(从转色期到红熟期)表达量明显减少。     

Photosynthesis and the Enzymes of Photosynthetic Carbon Reduction Cycle in Mulberry During Water Stress and Recovery

Net photosynthetic rate (P _N), stomatal conductance (g _S), transpiration rate (E), intercellular CO₂ concentration (C _i), leaf water potential (_w), leaf area, chlorophyll (Chl) content, and the activities of photosynthetic carbon reduction cycle (PCR) enzymes in two mulberry (Morus alba L.) cultivars (drought tolerant Anantha and drought sensitive M-5) were studied during water stress and recovery. During water stress, P _N, g _S, and E declined whereas C _i increased. P _N, g _S, and E were less affected in Anantha than in M-5, which indicates tolerance nature of Anantha over M-5. Activities of ribulose-5-phosphate kinase, NAD- and NADP-glyceraldehyde-3-phosphate dehydrogenases, and 3-phosphoglycerate kinase decreased with increasing stress in both the cultivars. The enzyme activities less affected in tolerant (Anantha) than in sensitive cultivar (M-5) were restored after re-watering to almost initial values in both the cultivars. Re-watering of the plants led to an almost complete recovery of P _N, E, and g _S, indicating that a short-term stress brings about reversible effect in these two cultivars of mulberry.     

Regional Distributions of Thiobarbituric Acid-Reactive Products, Activities of Enzymes Regulating the Metabolism of Oxygen Free Radicals, and Some of the Related Enzymes in Adult and Aged Rat Brains

Regional distributions of thiobarbituric acid-reactive products, activities of enzymes regulating metabolism of oxygen free radicals, and some of the related enzymes were studied in 10 areas of adult and aged rat brains. Thiobarbituric acid-reactive products were lower in cerebral cortex, septal area, hippocampus, caudate-putamen, and substantia nigra compared with other areas studied in adult rats; however, they increased significantly in the former areas with aging. A slight but significant reduction in superoxide dismutase activity was noted in frontal cortex, septal area, caudate-putamen, and substantia nigra with aging. Glutathione peroxidase and reductase activities were highest in caudate-putamen and in substantia nigra. Glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities were lowest in cortical areas. Phosphofructokinase activity was lowest in septal area and hippocampus in aged rats. Glyceraldehyde-3-phosphate dehydrogenase activity showed only small regional and evolutional changes. Lactate dehydrogenase activity declined with age in most of the areas studied. sn-Glycerol-3-phosphate dehydrogenase activity showed small changes with aging except in hippocampus, where 40% reduction was noted. Generally, cerebral cortical areas, hippocampus, and septal areas were not particularly enriched in enzymes regulating the metabolism of oxygen free radicals. The results were discussed in relation to the role of free radicals in aging.     

Effect of Boron as an Antidote on Dry Matter Intake,Nutrient Utilization and Fluorine Balance in Buffalo (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>) Exposed to High Fluoride Ration

Twenty male buffalo calves (8–9 months, 112.1 ± 7.69 kg) were divided into four groups of five animals in each and fed diets without (T1) or supplemented with 0.3 ppm selenium (Se) (T2), 0.3 ppm Se + 10 ppm copper (Cu) (T3), and 10 ppm Cu (T4) for 120 days during which blood samples were collected on day 0, 40, 80, and 120. Concentrations of glucose, total protein, urea, uric acid, and creatinine were similar in all the four groups, but the level of globulin was significantly (P < 0.01) increased in groups T2 and T3, leading to reduced levels of albumin and A:G ratio (P < 0.01) in these groups. The level of different serum enzymes viz. lactate dehydrogenase (LDH), alkaline phosphatase (ALP), glutamate pyruvate transaminase (SGPT), and glutamate oxaloacetate transaminase (SGOT) and hormones viz. T₃, T₄, testosterone and insulin and T₄:T₃ ratio were similar (P > 0.05) among the four groups. It was deduced that supplementation of 0.3 ppm Se and/or 10.0 ppm of Cu had no effect on blood metabolic profile in buffalo calves, except for an increased globulin level, indicating improved immunity status of these animals.     

Exogenous Calcium Enhances the Formation of Vegetative Buds,Flowers and Roots in Tobacco Pith Explants Cultured in the Absence of Exogenous Hormones

Pith explants excised from the apical stem internodes of vegetative, flowering, and fruiting tobacco plants were cultured on hormone-free medium in the presence or absence of CaCl₂ (3 mM). The aim was to determine the role of exogenous calcium (Ca²⁺), applied at the concentration normally present in the Murashige and Skoog (1962) medium, in organ formation obtainable in the absence of the exogenous hormonal input. Exclusive formation of vegetative buds was obtained from explants excised from vegetative plants (pure vegetative programme); vegetative buds and flowers (and occasionally roots) on the same sample were obtained from explants from flowering plants (mixed flowering programme); whereas roots, very occasionally associated with vegetative buds and flowers on the same sample, were obtained from explants from fruiting plants (mixed rooting programme). Histological analysis showed that the organs always exhibited indirect regeneration. Exogenous Ca²⁺ promoted the formation of meristemoids and the first phases of their growth into organs, but did not change the realization of the organogenic programme and did not affect callogenesis. Instead, the influence of exogenous Ca²⁺ changed with the programme, when considering the last phases of organ growth (i.e., macroscopic development and elongation), and the appearance of morphological anomalies in the organs.     

Isozyme polymorphism and organization of the agamic complex of the Maximae (Panicum maximum Jacq., P. infestum Anders,and P. trichocladum K. Schum.) in Tanzania

The tribe Maximae (Panicum maximum Jacq., P. infestum Anders., P. trichocladum K. Schum.) includes two sympatric pools with different modes of reproduction and ploidy levels: an apomictic and tetraploid pool on the one hand, and a smaller, sexual and diploid pool on the other. From an analysis of isozyme polymorphism five main results were evident. First, overall polymorphism is considerable showing that apomixis does not lead to a reduction in diversity. Second, the isozyme polymorphism of the two pools is similar, and this may be explained by reciprocal gene flow (low, but continuous) between these two pools. Third, maximum local polymorphism is due to the simultaneous presence of P. maximum sexuals and P. infestum apomicts. A continuum exists between the two species. Fourth, a high proportion of rare alleles, arising from introgression from P. infestum, characterized the isozyme polymorphism. These rare alleles, strongly counter-selected at the diploid level, are maintained by apomixis; the frequency of triplex or quadruplex genotypes was nevertheless low. Fifth, the heterozygosity level within apomicts is not higher than that of sexuals, showing that the apomixis-polyploidy combination does not lead to a higher frequency of very heterozygous individuals.     

A Microarray-Based Comparative Analysis of Gene Expression Profiles During Grain Development in Transgenic and Wild Type Wheat

Global, comparative gene expression analysis is potentially a very powerful tool in the safety assessment of transgenic plants since it allows for the detection of differences in gene expression patterns between a transgenic line and the mother variety. In the present study, we compared the gene expression profile in developing seeds of wild type wheat and wheat transformed for endosperm-specific expression of an Aspergillus fumigatus phytase. High-level expression of the phytase gene was ensured by codon modification towards the prevalent codon usage of wheat genes and by using the wheat 1DX5HMW glutenin promoter for driving transgene expression. A 9K wheat unigene cDNA microarray was produced from cDNA libraries prepared mainly from developing wheat seed. The arrays were hybridised to flourescently labelled cDNA prepared from developing seeds of the transgenic wheat line and the mother variety, Bobwhite, at three developmental stages. Comparisons and statistical analyses of the gene expression profiles of the transgenic line vs. that of the mother line revealed only slight differences at the three developmental stages. In the few cases where differential expression was indicated by the statistical analysis it was primarily genes that were strongly expressed over a shorter interval of seed development such as genes encoding storage proteins. Accordingly, we interpret these differences in gene expression levels to result from minor asynchrony in seed development between the transgenic line and the mother line. In support of this, real time PCR validation of results from selected genes at the late developmental stage could not confirm differential expression of these genes. We conclude that the expression of the codon-modified A.␣fumigatus phytase gene in the wheat seed had no significant effects on the overall gene expression patterns in the developing seed.     

镉胁迫对矮牵牛种子萌发、幼苗生长及抗氧化酶活性的影响

采用营养液培养的方法研究了不同浓度镉Cd（0、1、2和4 mmol·L^-1）处理对矮牵牛（Petunia hybrida）种子萌发、幼苗生长及生理特性的影响。结果发现：与对照相比,较低浓度（1 mmol·L^-1）Cd处理下矮牵牛种子萌发和幼苗生长均显著被抑制,当Cd浓度增至4 mmol·L^-1时完全抑制了矮牵牛种子的萌发。Cd胁迫在低浓度时激活矮牵牛幼苗叶片过氧化物酶（POD）、过氧化氢酶（CAT）活性,而高浓度产生抑制效应;抗坏血酸过氧化物酶（APX）和超氧化物歧化酶（SOD）活性与对照相比均显著升高,丙二醛（MDA）含量无显著变化。不同浓度的乙二胺四乙酸(EDTA)的加入使4 mmol·L^-1 Cd胁迫下矮牵牛幼苗叶片POD和APX活性增加,但不影响SOD和CAT活性;此外,6 mmol·L^-1 EDTA使Cd胁迫下矮牵牛幼苗叶片中MDA含量增加。结果表明,Cd胁迫抑制矮牵牛种子萌发和幼苗生长,却使幼苗叶片POD、CAT和APX活性增加,EDTA的加入能够进一步提高Cd胁迫幼苗POD和APX活性。因此,矮牵牛幼苗在Cd胁迫下具有较强的抗氧化损伤的能力。     

Therapeutic Potential of Riboflavin,Niacin and Ascorbic Acid on Carbohydrate Metabolizing Enzymes in Secondary Endometrial Carcinoma Bearing Rats

Curative potential of riboflavin, niacin and ascorbic acid against tamoxifen mediated endometrial carcinoma was established by studies on carbohydrate metabolizing enzymes. The enzymes investigated were glycolytic enzymes namely, hexokinase; aldolase; phosphoglucoisomerase and the gluconeogenic enzymes namely, glucose-6-phosphatase and fructose-1, 6-biphosphatase in endometrial carcinoma bearing rats. A significant increase in glycolytic enzymes and a subsequent decrease in gluconeogenic enzymes were observed in plasma, liver and kidney of endometrial carcinoma animals. The administration of riboflavin (45 mg/kg bw/day), niacin (100 mg/kg bw/day) and ascorbic acid (200 mg/kg bw/day) along with tamoxifen (45 mg/kg bw/day) caused a significant decrease in the activity of glycolytic enzymes and a significant increase in the activities of gluconeogenic enzymes to near normal levels in experimental animals. Our results suggest that riboflavin, niacin and ascorbic acid have potential combination therapy against tamoxifen mediated secondary endometrial carcinoma in experimental rats. However, there were no deleterious side effects observed in combinants alone treated animals.     

甘蔗节间蔗糖含量与和蔗糖代谢相关的4种酶活性之间的关系剖析

测定和分析2个品种甘蔗节间蔗糖含量与和蔗糖代谢相关的4种酶活性之间关系的结果表明:节间蔗糖含量与酸性转化酶活性成极显著负相关,与蔗糖磷酸合成酶活性呈显著正相关。从通径分析结果可知,4种关键酶中可溶性酸性转化酶和蔗糖磷酸合成酶是对蔗糖含量贡献程度最大的2个酶.     

过量铜、锌对外生菌根菌牛乳牛肝菌生物量、呼吸和糖酵解酶活性的影响

在过量铜或锌胁迫下,独立培养的外生菌根菌牛乳牛肝菌（Suillus     

番茄 SlDP1 基因的克隆、生物信息学及表达特性分析简

DP基因属于DP/E2F转录因子家族,其编码的蛋白是E2F蛋白的二聚化分子伴侣,可能参与调控细胞周期、DNA复制、生长、分化、凋亡等多种细胞进程。根据SGN数据库登录的番茄序列,通过RT-PCR方法从野生型番茄中克隆了一个DP基因,命名为SlDP1。生物信息学预测,SlDP1蛋白定位于细胞核,具有保守的DNA结合域、二聚化区域和C-末端及多个磷酸化位点。蛋白质二级结构预测SlDP1蛋白含51.50%的环状结构,34.55%的α螺旋和2.66%的β折叠。荧光定量PCR分析外源激素对野生型番茄SlDP1基因表达量的影响,发现该基因受外源性乙烯前体ACC的诱导。对环境因子应答的RT-PCR结果表明,在伤害和盐处理的叶中该基因表达不受诱导,而盐处理的根中该基因表达量提高。SlDP1基因表达模式分析表明,该基因在根、花、萼片及成熟时期果实中表达量较高。这些结果为进一步研究SlDP1基因在番茄生长发育过程的功能奠定了基础。     

Analysis of Growth and Water Relations of Tomato Fruits in Relation to Air Vapor Pressure Deficit and Plant Fruit Load

The influence of air vapor pressure deficit (VPD) and plant fruit load on the expansion and water relations of young tomato fruits grown in a glasshouse were evaluated under summer Mediterranean conditions. The contributions of phloem, xylem and transpiration fluxes to the fruit volume increase were estimated at an hourly scale from the growth curves of intact, heat-girdled and detached fruits, measured using displacement transducers. High VPD conditions reduced the xylem influx and increased the fruit transpiration, but hardly affected the phloem influx. Net water accumulation and growth rate were reduced, and a xylem efflux even occurred during the warmest and driest hours of the day. Changes in xylem flux could be explained by variations in the gradient of water potential between stem and fruit, due to changes in stem water potential. Misting reduced air VPD and alleviated the reduction in fruit volume increase through an increase in xylem influx and a decrease in fruit transpiration. Under low fruit load, the competition for assimilates being likely reduced, the phloem flux to fruits increased, similarly to the xylem and transpiration fluxes, without any changes in the fruit water potential. However, different diurnal dynamics among treatments assume variable contributions of turgor and osmotic pressure in F3 and F6 fruits, and hypothetical short-term variations in the water potential gradient between stem and fruit, preventing xylem efflux in F3 fruits.