Fermentative Production of Chloramphenicol-analogs (Corynecins) from Sucrose

Corynecins (N-acyl derivatives of d-(?)-threo-p-nitrophenyl serinol), which were firstly discovered in the culture broth of Corynebacterium hydrocarboclastus KY 4339 grown on n-alkane were also produced when n-alkane was replaced by sucrose. The corynecins production in the sucrose-medium was significantly stimulated by the supplement of molasses. On the basis of the composition of ingredients in molasses, the preferable culture medium was designed for the production of corynecins from sucrose. This semi-synthetic medium is consisted of low concentration of phosphate, high concentration of potassium chloride, inositol, fructose and yeast extract in addition to ordinary mineral salts. By controlling the pH of the medium at the neutral range and keeping the aeration at a relatively high level, approximately 4 g of corynecins (as l-base) per liter of the medium were produced using a 5-liter jar fermentor.     

烟粉虱成虫在日光温室内的分布和日活动规律

采用中色粘虫板(黄板)和植株调查方法在河北省固安县日光温室内研究了烟粉虱成虫在黄瓜结瓜盛期(4月下旬~5月上旬)的分布和日活动规律。结果表明,温室北边平均诱集量((668·8±663·9)头/(板·d))是南边((357·5±349·4)头/(板·d))的1·87倍;除8∶00~10∶00以外,其他时段内北边诱集量均显著高于南边;同时,北边植株上烟粉虱成虫数量也显著高于南边。温室东边逐日和各时段诱集量均高于西边,但差异不显著。在垂直方向,烟粉虱成虫在黄瓜所有叶片上均有分布。烟粉虱成虫从6∶00~18∶00各时段均很活跃,但不同时段活动水平存在差异。8∶00~10∶00平均诱集比例最高(25·7%±9·7%),12∶00~14∶00最低(13·2%±5·2%);8∶00~10∶00的诱集量显著高于其他时段。另外,黄板南面诱集量((352·5±186·1)头/(板·d))显著高于北面诱集量((160·7±90·4)头/(板·d))。对日光温室黄瓜上烟粉虱的监测、成虫诱杀和综合治理的意义进行了讨论。     

Design and use of a simulation model to evaluate germplasm for antibiotic resistance to the greenhouse whitefly (Trialeurodes vaporariorum) and the sweetpotato whitefly (Bemisia tabaci)

SARAH (Software for theAssessment of antibioticResistance toAleyrodidae inHost plants) is a deterministic simulation model of whitefly population growth based on whitefly life-history components determined on individual plants. The life-history components recorded were oviposition rate, adult survival, pre-adult survival, developmental period, and sex ratio. The simulation model serves as a tool to combine these components and to obtain a single criterion for (antibiotic) resistance. The criterion used was the decrease in simulated intrinsic population growth rate, r _s , relative the r _s value determined on a susceptible control genotype. This model-based evaluation method was tested using the greenhouse whitefly,Trialeurodes vaporariorum Westwood, on tomato and the sweetpotato whitefly,Bemisia tabaci Gennadius, on tomato, eggplant, collard, and pepper. To study its consistency over time, the evaluation method was repeated six times forT. vaporariorum on a susceptible and a resistant tomato cultivar. Simulated intrinsic population growth rate was more consistent in indicating resistance than any of the individual life-history components. Of tenL. hirsutum accessions tested for resistance toT. vaporariorum, three exhibited r _s values that were significantly lower than those for the susceptible control. In addition, on these tenL. hirsutum accessions, a significant positive correlation was observed between r _s and sex ratio (# females/# males). Four host plant species (tomato, collard, eggplant, and pepper) were evaluated for resistance toB. tabaci. All life-history components and r _s values varied among host species, while a negative r _s value was observed forB. tabaci on pepper. A high correlation was found between results from a sensitivity analysis of SARAH and results from a sensitivity analysis of a validated whitefly population simulation model by Yanoet al. (1989a). Significant correlations were found for the relationships between oviposition rate, adult survival, or pre-adult survival and r _s , indicating that none of these life-history components can be omitted from the test procedure. This model-based evaluation method offers a standardized way to quantify levels of antibiotic resistance to whiteflies and will enhance efficiency in breeding programs.     

Distribution of proteinases and carbohydrases in the midgut of larvae of the sweetpotato weevilCylas formicarius elegantulus and response of proteinases to inhibitors from sweet potato

Endoproteinase activity was confined to luminal fluid from anterior and posterior ventricular regions of midguts of larvae of the sweetpotato weevil,Cylas formicarius elegantulus (Summers). Aminopeptidase was found in luminal fluid (18%) but was primarily associated with insoluble fractions from cells of the posterior ventriculus (82%). Depending on substrate, carboxypeptidase activity was about equally distributed between luminal fluid and insoluble fractions from posterior ventriculus cells. Amylase was found in luminal fluid in both the anterior and posterior ventriculus. Five bands of amylase activity were detected on starch zymograms following electrophoresis of whole midgut samples. Three of the amylase bands may be plant-derived. At least two -glucosidases were present, one secreted and one bound to anterior ventriculus cells. -Glucosidase activity was bound to anterior ventriculus cells whereas -galactosidase activity was confined to luminal fluid. -Galactosidase and cellulase activities were found in both luminal fluid and the insoluble cell fraction. Thus, initial digestion of large protein and carbohydrate polymers occurs in luminal fluid in both anterior and posterior ventriculus regions. However, terminal digestion of oligopeptides occurs primarily in the posterior ventriculus while terminal digestion of oligosaccharides occurs in the anterior ventriculus.A 20-fold difference in trypsin-inhibitor concentration was found among five sweetpotato cultivars. Endoproteinases from sweetpotato weevil larvae were inhibited by extracts from the cultivars but cultivars with relatively high concentrations of inhibitor were previously shown to be susceptible to weevil attack in field trials.

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Distribution des protéinases et des carbohydrases dans l'intestin moyen des larves deCylas formicarisus elegantulus et réponse des proténases aux inhibiteurs d'Ipomoea batatas

Résumé L'activité endoprotéinase était limitée au liquide de la lumière des régions ventriculaires antérieure et postérieure de l'intestin moyen des larves deCylas formicarius elegantulus Summers. Les aminopeptidases ont été trouvées dans le liquide de la lumière (18%), mais étaient principalement associées avec les fractions insolubles des cellules du ventricule postérieur (82%). Suivant le substrat, l'activité carboxypeptidase était à peu près également répartie entre le liquide de la lumière et les fractions insolubles des cellules du ventricule postérieur. L'amylase, enzyme secrétée, a été observée à la fois dans la lumière antérieure et postérieure. Cinq bandes d'activité amylase ont été révélées sur zymogrammes d'amidon après électrophorèse d'intestins moyens entiers. Trois des bandes d'amylase pouvaient provenir de la plante. Il y avait au moins 2 -glucosidases, une secrétée et une liée aux cellules du ventricule antérieur. L'activite -glucosidase était liée aux cellules du ventricule antérieur, fandis que l'activité -galactosidase était limitée au fluide de la lumière. Les activités -galactosidase et cellulase ont été trouvées à la fois dans le liquide de la lumière et dans la fraction cellulaire insoluble. Ainsi, la digestion initiale des grosses protéines et des polymères de carbohydrates se produit dans le liquide de la lumière dans les régions ventriculaires antérieure et postérieure. Cependant, l'achèvement de la digestion des oligopeptides se produit principalement dans le ventricule postérieur, tandis que la fin de la digestion des oligosaccharides se produit dans le ventricule antérieur.Les concentrations en inhibiteurs de trypsine de 5 cultivars d'I. batatas L. diffèrent de 1 à 20. Les endoprotéinases deC. formicarius elegantulus ont été inhibées par des extraits de cultivars, mais les cultivars avec des concentrations relativement élevées d'inhibiteur avainent antérieurement montré être susceptibles d'être attaqués par le coléoptère dans des essais en champs.

     

Development of pheromone traps for control and monitoring of sweetpotato weevils, Cylas puncticollis and C. brunneus, in Uganda

Experiments were carried out in Uganda to optimise pheromone traps for the African sweetpotato weevil species, Cylas puncticollis Bohe. and C. brunneus F. (Coleoptera: Apionidae). Various designs of funnel, water and sticky traps were compared and a 5-l plastic jerry can trap was the most appropriate design for effectiveness and practicability. A solution of Omo detergent in water was found to be the most effective trapping agent. Fewer weevils were caught in red traps than in yellow, white, green or blue traps. Catches of C. puncticollis increased when the trap was raised above crop height, but catches of C. brunneus were unaffected. When marked weevils were dropped onto the trap, 36% of C. puncticollis and 23% of C. brunneus were captured, and, of weevils placed in the trap, 88% and 92%, respectively, of the two species remained overnight. Lures for the two species showed no significant loss in attractiveness after 8 weeks in the field, and chemical analysis showed 19% of the C. puncticollis pheromone and 72% of the C. brunneus pheromone remaining after this time. Summarizing, the following trap is presently recommended for monitoring/controlling African Cylas species: a 5-l plastic jerry can trap of any colour with rectangular openings of 11×5 and 6×5 cm positioned 15 cm above the crop canopy, filled with 0.5 l Omo solution (1 g/1 l water), with 0.1 mg lures to be replaced every 8 weeks.     

甘薯(Ipomoea batatas L.)遗传转化几个因素的研究

目的:提高甘薯的遗传转化率,为建立快速高效的甘薯遗传转化体系奠定基础。方法:以甘薯多个优良栽培品种无菌苗茎切段为受体,利用农杆菌LBA4404/pSP10Z做介导,研究了影响甘薯转化的几个因素。结果:接种侵染时间对转化效率影响很大,以2~15min为宜,最高转化率可达32.14%;不同基因型的转化受体之间转化率差别较大;在培养过程中最后30min加入终浓度为50μmol/L AS的接种菌侵染的外植体,转化率较对照提高了2.02倍;共培养培养基中加入终浓度为50μmol/L的AS,转化率较对照组提高了6.11倍;AS终浓度为50μmol/L同时pH为4.8的共培养培养基有利于转化的发生,转化率较对照组提高了1.73倍;共培养培养基中脯氨酸的添加并不能提高转化率。结论:该研究为快速高效甘薯遗传转化体系的建立提供了依据。     

Sperm storage and viability within females of Euscepes postfasciatus: Effect of irradiation on sperm abundance and viability within female

Irradiation has been widely used in suppression or eradication programs that use the sterile insect technique (SIT) or in studying sperm competition. Although it is well known that irradiation has negative impacts on reproductive (sperm) cells, previous studies have assumed that sperm from irradiated males behave identically to normal sperm in the female reproductive tract after mating. In this study, we used the West Indian sweetpotato weevil Euscepes postfasciatus to investigate the effect of irradiation on the abundance and viability of sperm in female spermatheca for 14 days after copulation. The abundance of sperm in females did not change throughout the experimental period, and sperm viability gradually decreased regardless of irradiation. In this weevil, irradiated sperm appear to behave identically to normal sperm in females for 14 days following irradiation/copulation. Therefore, the effect of irradiation on sperm viability within the female spermatheca is considered to be insignificant.     

烟粉虱在温室内甘薯寄主上生物学特性的研究

对烟粉虱Bemisia tabaci(Gennadius)在温室内甘薯寄主上主要生物学特性的研究表明：烟粉氮成虫喜光、喜湿,晴朗高温时活动性强,但扩散飞行能力弱;多在白天交尾,多在中午产卵,具有强的惫鬃性．若虫一生脱皮3次,若虫(除一龄初期)固定生活。卵的孵化及成虫的羽化也多发生在中午。雌雄性比为1．628：1,成虫平均寿命14．25天,雌成虫平均寿命比雄成虫长6．9天,每雌平均产卵158．5粒。以两性生殖为主,也可孤雌生殖,两性生殖的产卵量及卵孵化率均高于孤雌生殖。     

不同培养方法对甘薯无菌苗生长的影响

试验结果表明,在甘薯组织培养中液体培养不降低无菌苗生长势,对无菌苗生长有一定促进作用,适合于甘薯无菌苗的快速繁殖。液体培养20d比相同条件下固体培养的无菌苗植株高度高出63．16％,经方差分析,差异显著,具有统计学意义;液体培养60d比相同条件下固体培养的无菌苗植株高度,单株叶片数,单叶面积分别高出59．43％,106．70％,49．82％,经方差分析,前两者差异显著,具有统计学意义。     

基于图像RGB特征值的甘薯色素与肉色关系初步探讨

为明确甘薯色素、干率与肉色的关系,给图像RGB特征值评估甘薯色素含量提供依据,测定了甘薯240份品系的胡萝卜素含量及234份品系的花青素含量、干率和薯肉RGB颜色特征值。结果表明,甘薯胡萝卜素含量与RGB值的相关系数r=-0.913,偏相关系数为-0.872,花青素含量与RGB值的相关系数r=-0.838,偏相关系数为-0.836,说明甘薯色素含量与肉色是高度正相关的,是肉色的决定因子,但胡萝卜素与肉色关系更紧密。干率与胡萝卜素RGB值的相关系数r=0.597,偏相关系数为0.273,干率与花青素RGB值的相关系数r=-0.273,偏相关系数为0.255,说明干率与对肉色有极明显的负面影响,但是在RGB值≥200的低胡萝卜素(约含量3 mg/100 g·FW以下)群体中,干率与RGB值的偏相关系数为-0.0066(P=0.9426),干率对低胡萝卜素含量品系的肉色没有影响。采用R值、G值、B值、干率的二次多项式回归模型,RGB值≥200的低胡萝卜素群体、RGB值200的较高或高胡萝卜素群体和花青素群体的拟合方程的复相关系数R分别为0.975、0.982和0.937,说明拟合值与实测值关系十分密切。对胡萝卜素含量高于3 mg/100 g·FW的品种,拟合值能达到约90%的精确度,对胡萝卜素含量低于3 mg/100g·FW的品种,也能达到约83%的精确度,对花青素品种能达到约86%的精确度。因此,图像RGB特征值法不仅能够很好地反映甘薯品种间的色素差异,还能较精确地估测甘薯色素含量,可为甘薯早代育种的大批量样品提供便捷、客观的色素含量评估方法。