Chloroplast biogenesis 91: Detection of δ-aminolevulinic acid esterases activity in higher plant and insect tissues

δ-Aminolevulinic acid (ALA) esterase(s) is an enzyme or a family of enzymes that regenerate ALA from ALA esters by hydrolysis. These enzyme(s) are highly active in cancer cells. As a consequence ALA esters have been used to advantage in ALA-dependent photoradiation therapy, since ALA esters translocate better to sites of metabolism in cancer cells and tissues than free ALA. In this work, it is shown that ALA esterase(s) also occur in insect and plant tissues, but are less active than in cancer cells. In plant cells ALA esterase activity is observed in the cytosol as well as in the plastids where most of the activity is observed in the plastid stoma. The ALA esterase activity appears to be sensitive to the nature of the esterifying alcohol as well as to components of the incubation medium. The observed lower activity of ALA ester conversion to tetrapyrroles in insect and plant cells, in comparison to free ALA, suggests that the use of ALA esters in photodynamic insecticidal and herbicidal applications may not be as advantageous as their use in cancer photodynamic therapy treatments. It is proposed that ALA esterase(s) may be involved in the mobilization of sequestered and esterified ALA. Esterification and sequestering of excess ALA may be visualized as a mean of cellular detoxification.     

狭卵链格孢菌毒素细交链孢菌酮酸对稗草细胞膜脂质过氧化作用的影响

为明确狭卵链格孢菌Alternaria augustiovoide菌株AAEC05-3产生的毒素细交链孢菌酮酸(tenuazonic acid,TeA)的作用机制,利用离体试验,研究了TeA对稗草叶片细胞膜脂质过氧化的影响。结果显示,低浓度TeA处理对稗草叶片的细胞膜透性和脂质过氧化影响不大;用高浓度TeA处理稗草叶片24 h后,稗草叶片细胞膜透性和脂质过氧化作用显著增强。TeA浓度为100 μmol/L时,稗草叶片相对电导率和丙二醛(MDA)含量分别增加28.21%和63.58%;脂氧合酶(Lox)活性增高61.59%,且不饱和脂肪酸含量显著降低,亚油酸(18∶2)和亚麻酸(18∶3)分别降低19.56%和17.20%,脂肪酸氢过氧化物在叶片中大量积累。表明TeA可以诱导稗草叶片细胞膜的脂质过氧化作用。     

我国玉米穗腐病致病镰孢种群及禾谷镰孢复合种的鉴定

为阐明中国玉米镰孢穗腐病的主要致病镰孢菌种类及其分布特征,采用形态学、培养特征及特异性分子鉴定方法,对采集自我国18省100个县的玉米籽粒样品进行分离鉴定,并通过TEF-1α基因序列测定解析禾谷镰孢复合种的构成.结果表明,在我国引起玉米穗腐病的主要致病菌为镰孢菌,分离频率为56.0%,其次还有青霉菌、曲霉菌、木霉菌等.138个镰孢菌分离物中鉴别出7个种及复合种,其中拟轮枝镰孢菌Fusarium verticillioides(56.5%)和禾谷镰孢复合种F.graminearum species complex(37.7%)为广泛分布的优势致病种类,其余为黄色镰孢菌F.culmorum(2.2%)、层出镰孢菌F.proliferatum(1.5%)、尖镰孢复合种F.oxysporum species complex(0.7%)、茄镰孢复合种F.solani species complex(0.7%)和亚粘团镰孢菌F.subglutinans(0.7%).在禾谷镰孢复合种中鉴定出3个独立种:广泛分布的禾谷镰孢菌F.graminearum sensu stricto(59.6%)、分布在云南、贵州及陕西商洛等南方生态区的南方镰孢菌F.meridionale(25.0%)和分布在内蒙古、吉林、山西、河北及北京等北方生态区的布氏镰孢菌F.boothii(11.5%).     

Effect of Melia azedarach extract on the activity of NADPH-cytochrome c reductase and cholinesterase in insects

The effect of Melia azedarach extract on the activity of NADPH-cytochrome c reductase and cholinesterase was studied in Spodoptera frugiperda. Larvae were fed an artificial diet containing fruit extract and their midgut was used for enzyme determination. As compared to the control, consumption of the extract containing diet resulted in a 31% inhibition of the cholinesterase activity and a 34% activation of the NADPH-cytochrome c reductase activity. In the cockroach Leucophaea maderae, the effect on reductase activity was even more pronounced (43%).     

Bt-maize effects on biological parameters of the non-target aphid Sitobion avenae (Homoptera: Aphididae) and Cry1Ab toxin detection

Bt-maize crop is increasingly used worldwide and the study of ecological side effects is a major subject in this domain. Under laboratory conditions, we determined Bt-maize effects on the non-target aphid Sitobion avenae (Fabricius) (Homoptera: Aphididae). We found no significant differences between S. avenae on MON810 and the near-isogenic line when alate offspring production, apterous survivorship, longevity, intrinsic rates of natural increase (r_m), finite rates of increase and doubling times were compared. No significant differences were found between treatments for apterous pre-reproductive and reproductive periods. Additionally, we used immunological tests (ELISA) to detect Cry1Ab protein in maize leaves and S. avenae nymphs. Results showed that Bt-maize leaves expressed 0.203 (±0.05) μg Cry1Ab/g leaf tissue (Mean ± SEM). No Cry1Ab protein was present in S. avenae nymphs developing on Bt or conventional maize. We conclude that Bt-maize does not affect the development of the non-target aphid S. avenae and that Cry1Ab toxin quantities in these aphids are nil, suggesting an inconsequential risk for natural enemies of this aphid species.     

芳香植物气味及提取液对茶尺蠖行为的影响

为了明确芳香植物对茶尺蠖Ectropisobliqua的驱避、拒食作用和获得应用于茶园茶尺蠖"推-拉"策略的植物材料,利用"Y"型嗅觉仪室内测定其成虫对芳香植物气味的趋性反应,并采用叶碟法测定芳香植物提取液对其幼虫的拒食作用及营养干扰效果。丁香罗勒、迷迭香、柠檬桉和芸香植株挥发物及甲醇提取液对茶尺蠖雌、雄成虫有显著的驱避效果。猫薄荷、迷迭香和鼠尾草的2 00 mg/mL甲醇提取液对茶尺蠖3龄幼虫表现出显著拒食活性,24 h后的选择性拒食率分别为93.85%、86.00%和77.32%,非选择性拒食率分别为85.77%、87.00%和88.05%。其中,迷迭香处理的幼虫生长率最低,仅为0.12 mg/天,对幼虫的相对取食量、食物利用率和食物转化率等营养指标有影响。研究表明,10种芳香植物中迷迭香具有显著的行为调控功能,是构建茶尺蠖"推-拉"策略的理想材料。     

朝鲜球坚蚧对8种寄主植物的产卵和取食选择性及其机制

采用笼罩法研究了朝鲜球坚蚧对8种寄主的选择性及其与寄主枝条物理结构、寄主和蚧体内化学物质问的关系.结果表明,朝鲜球坚蚧对8种寄主的取食和产卵的选择性差异均达极显著水平,由强到弱依次为桃、梅、李、杏、苹果、梨、樱桃和山楂,且分成桃、梅、李、杏,苹果、梨、樱桃,以及山楂3个寄主层次.取食和产卵选择性一致,分别与8种寄主的表皮毛密度、长度、皮层厚度、枝条直径、黄酮以及单宁等间达极显著负相关,相关系数r分别为-0.9413～-0.8816和-0.9624～-0.8943;同时分别与8种寄主的可溶性糖、蛋白质、游离氨基酸、含水量、CarE、AChE、GSTs和蚧体可溶性蛋白质等间达极显著正相关,r分别为0.9025～0.9413和0.8937～0.9201.以取食表皮较为光滑、表皮毛稀疏、长度短、皮层薄、寄主可溶性蛋白质、游离氨基酸和含水量多、含黄酮和单宁少的桃、梅、李和杏等寄主的蚧体内CarE、AChE、GSTs的活性和可溶性蛋白质含量较高,对寄主选择性较强;取食苹果、梨和樱桃的次之;取食山楂的最低.     

Effect of pesticides on phosphate solubilization by Bacillus sphaericus and Pseudomonas cepacia

Intensive screening of phosphate solubilizing bacteria with genetic potential for increased tolerance to high salt, high pH and high temperature could enhance production of food and forage in semi-arid regions. Emphasizing particularly on this hypothesis 165 phosphate solubilizing bacteria was isolated. Among these, two cultures Bacillus sphaericus and Pseudomonas cepacia were selected on the basis of salt tolerance property and PS activity with different forms of phosphates. In the present investigation both these culture were assessed for the effect of six different pesticides, to confirm its successful realistic application as microbial inoculants in actual farm conditions. Both cultures showed better phosphate solubilizing activity with phosphate containing pesticides. Among these two isolates P. cepacia was a better performer in terms of phosphate solubilizing activity with different pesticides. It may be due to its well documented extra ordinary, versatile metabolic activity. The present study may prove them to be potential candidates to be used as microbial inoculants.     

Biological and biochemical parameters of Biomphalaria alexandrina snails exposed to the plants Datura stramonium and Sesbania sesban as water suspensions of their dry powder

Four plant species, as a dry powder of their leaves, were tested against Biomphalaria alexandrina snails, the intermediate host of Schistosoma mansoni. The bioassay tests revealed the plants Datura stramonium and Sesbania sesban to be more toxic to the snails than the other two ones. Therefore, they were tested against snails’ fecundity (M_x), reproduction rate (R_o) and their infection with S. mansoni miracidia. In addition, total protein concentration and the activities of the transaminases (AsT and AlT) and phosphatases (AcP and AkP) enzymes in hemolymph and tissues of snails treated with these plants were determined. As well, glucose concentration in snails’ hemolymph was evaluated.Exposure of snails for 4 weeks to LC₁₀ and LC₂₅ of the plants D. stramonium and S. sesban dry powder markly suppressed their M_x and R_o. The reduction rates of R_o for snails exposed to LC₂₅ of these plants were 62.1% and 76.4%, respectively. As well, a considerable reduction in the infection rates of snails exposed to these plants either during, pre- or post-miracidial exposure was recorded. Thus, infection rates of snails treated during miracidial exposure with LC₁₀ of D. stramonium and S. sesban were 41.7% and 52.2%, respectively, compared to 92.6% for control group (P < 0.01). These plants, also, reduced the duration of cercarial shedding and cercarial production/snail. So, snails exposed to LC₂₅ of these plants shed 372.8 and 223.2 cercariae/snail, respectively, compared to 766.3 cercariae/infected control snail (P < 0.01).The results, also, revealed that glucose and total protein concentrations in hemolymph of snails treated with LC₁₀ and LC₂₅ of these plants were decreased, meanwhile, the activities of the enzymes AsT, AlT, AcP and AkP were elevated (P < 0.01). However, the activity of AcP in tissues of treated snails was decreased compared to that of control ones. It is concluded that LC₂₅ of the plants D. stramonium and S. sesban negatively interferes with biological and physiological activities of B. alexandrina snails, consequently it could be effective in interrupting and minimizing the transmission of S. mansoni.     

我国部分地区玉米丝核菌组成及其致病类型分析

IA为主要融合群;双核丝核菌为AG-A融合群;单核丝核菌种类尚不确定.对各融合群的致病类型进行初步比较发现,属于AG1-IA融合群的菌株,可在玉米叶鞘形成典型的云纹状病斑,其它菌株虽可引起玉米发病,但与AG1-IA的症状存在明显差异.     

寄主和非寄主植物对桑皱鞘叶甲取食行为的影响

为深入了解桑皱鞘叶甲Abirus fortunei （Baly）取食行为机制,探索安全有效的行为调控技术,通过观察其在寄主和非寄主植物上取食行为的差异,应用“Y”型嗅觉仪测试其对寄主和非寄主植物叶片气味的嗅觉行为反应,分析了寄主植物主要养分与其取食量之间的相关性。结果表明,桑皱鞘叶甲雌雄成虫在24 h内的取食选择率分别为70%和35%,其中70%以上叶甲偏向寄主植物桑树取食,对桑树嫩叶和老叶的平均取食量分别为0.21 g和0.19 g,二者无显著差异。桑皱鞘叶甲对寄主和非寄主植物叶片气味的嗅觉行为反应与对照差异不显著;其取食量与寄主植物叶片含水量、可溶性糖和蛋白质含量之间无明显相关关系。表明桑皱鞘叶甲的取食行为不受植物气味和主要营养物质的影响。     

灌淤土小麦／玉米间套不同供磷水平群体产量和根系生长形态分析

采用根箱法在不同供磷水平下,对春小麦和玉米在间作和单作情况下的产量和根系形态进行了比较研究。结果表明,适量的供磷能促进小麦、玉米产量的提高,过高反而减少。在施纯P2O50.1 g/kg土(P1)、0.2g/kg土(P2)0、.3 g/kg土(P3)的3个供磷水平下,P2水平和P3水平比P1水平总体产量增长55.09%和40.17%;籽粒产量增长51.28%和56.27%。单作小麦生物产量提高了35.89%~41.11%,穗粒重提高了21.71%~65.79%。随供磷水平的增加,整个根系根重基本上呈现出先增加后减少的趋势,但均高于低磷水平。单作小麦和间作玉米的根长在0~50 cm的土层中随供磷水平的增高,呈增长趋势,相对于低磷水平其增长幅度分别为11.78%~31.16%和39.83%~53.76%,而单作玉米根长呈先增加后减少的趋势。     

嘧菌酯对番茄早疫病菌的抑制作用

采用菌丝生长速率法和孢子萌发法分别测定了嘧菌酯对番茄早疫病菌Alternaria solani菌丝生长的抑制作用及其对分生孢子萌发的影响,同时测定了其对菌丝呼吸速率的影响。结果表明,嘧菌酯抑制番茄早疫病菌分生孢子萌发的作用强于对菌丝生长的抑制作用。抑制菌丝生长的剂量-反应曲线与抑制菌丝呼吸的剂量-反应曲线趋势相似,但菌丝在经嘧菌酯处理5~7 h后呼吸速率恢复到对照水平,相比之下,嘧菌酯却能一直抑制菌丝的生长。因此,采用孢子萌发法测定番茄早疫病菌对嘧菌酯的敏感性比用菌丝生长速率法测定更为适宜。水杨肟酸与嘧菌酯在抑制番茄早疫病菌菌丝生长和分生孢子萌发方面有协同作用,对菌丝生长的平均协同系数为7.24。随处理时间延长,药剂对菌丝耗氧的抑制作用下降,但仍抑制菌丝生长。研究表明:呼吸作用对药剂的敏感性随着处理的延长而下降的机理不是因为旁路氧化途径增强, 也不是因为基质中药剂效力的下降,而是存在其它机制。     

Activity of glutathione S-transferase toward some herbicides and its regulation by benoxacor in non-embryogenic callus and in vitro regenerated tissues of Zea mays

A procedure was developed to obtain non-embryogenic callus and regenerated lines from root segments of Zea mays grown in aseptic conditions. The activity of glutathione-S-transferases (GSTs), for non-embryogenic callus, was determined toward 1-chloro-2,4-dinitrobenzene (CDNB) and it was compared with that obtained for corn seedlings grown without hormones. For the callus masses, increases of specific activity toward CDNB and the kinetic parameter V_max were observed with respect to corn seedlings. The procedure permitted the regenerating of tissues from callus explants, therefore the GST(CDNB) activity and the effect of the safener benoxacor on its expression were investigated for the regenerated tissues grown in agarized substrate and in liquid medium. These explants showed a constitutive GST(CDNB) activity higher than corn seedlings and this activity was increased, for both tissues, in response to the presence of the safener benoxacor in the growing medium. The GST activity for the above tissues was also assayed toward benoxacor and terbuthylazine, metolachlor and fluorodifen herbicides. Measurable GST activity was found toward some of the above chemicals and it was found to be significantly enhanced in response to benoxacor treatment.     

不同温度对燕麦孢囊线虫田间群体孵化的影响

为明确不同温度经历燕麦孢囊线虫的孵化特点,分别于10月初小麦播种时和土壤结冻前即12月底采集大量燕麦抱囊线虫孢囊,在室内离体条件下分别测试不同温度对其孵化的影响。小麦播种时采集的燕麦孢囊线虫经5℃恒温处理的孵化高峰期为处理后第10～12周,比15℃恒温处理推迟了约4周;前期置于5℃培养,然后再转至15℃处理的孢囊,5℃处理时间越长,孵化高峰期越滞后;此外,随着5℃低温处理时间的增加,其总孵化率具有增加的趋势。12月底采集的孢囊在5—30℃条件下均有孵化,其最佳孵化温度为20℃,在此温度下其总孵化率最高,且孵化期最短;25℃以上高温对卵的孵化具有显著的抑制作用。     

Unravelling the physiologic and metabolic action of thiamethoxam on rice plants

We investigated some physiological and biochemical effects promoted by the insecticide thiamethoxam on rice crops. Two experiments were carried under pest-free conditions, in the greenhouse, with thiamethoxam at doses of: 0, 17.5, 35.0, 70.0 and 105.0 g a.i. per 100 kg of seeds. In order we check the physiology, biochemistry and production. In the first experiment thiamethoxam alter the content of photosynthetic pigments, as well as the enzymatic activity of phenylalanine ammonia-lyase, and in the second experiment this molecule modified the root development and nitrate reductase activity in rice plants. We believe that the thiamethoxam has potential to change the primary and secondary metabolism of rice plants, characterizing as a bioactivator.     

浙江衢州地区柑橘绿霉病菌对抑霉唑和多菌灵的抗性水平及其分子机制

研究了采自浙江衢州地区,包括柯城区、衢江区和开化县12个贮藏库的70个柑橘绿霉病菌Penicillium digitatum菌株对抑霉唑和多菌灵的抗性频率、抗性水平及其抗性分子机制。结果表明:柯城区和衢江区的抑霉唑抗性菌株(最低抑制浓度MIC≥0.5 μg/mL)的比例分别为77.1%和62.5%,两地抗性菌株的平均EC50值分别为2.07±1.04 μg/mL和2.35±0.73 μg/mL,分别是当地敏感菌株EC50值的41.4和47.0倍;而采自开化县的菌株均对抑霉唑敏感(MIC≤0.1 μg/mL),平均EC50值为0.04±0.02 μg/mL。柯城区和衢江区的多菌灵抗性菌株(MIC≥10 μg/mL) 的比例分别为54.3%和54.2%,而开化县的抗性菌株比例仅为9.1%。即来自柯城和衢江两个柑橘主产区的绿霉病菌群体对抑霉唑和多菌灵的抗性频率均远高于非柑橘主产区的开化县群体,说明抗药性群体的形成与药剂使用历史有关。进一步研究发现,衢州地区柑橘绿霉病菌对抑霉唑的抗性均属于IMZ-R3型,即与抑霉唑靶标基因 CYP51B 启动子区的插入突变有关,而对多菌灵的抗性则与 β-微管蛋白基因的992位核苷酸点突变(T→A)导致对应的200位点的氨基酸突变(F→Y)有关。     

纳他霉素对灰葡萄孢不同生育阶段菌体的毒力及其生物学性状的影响

以多菌灵为对照药剂,采用生长速率法、悬滴法和浸渍法分别测定了不同温度下纳他霉素对灰葡萄孢Botrytis cinerea菌丝生长、分生孢子萌发和菌核萌发的毒力,研究了常温下两种药剂对菌株产孢和菌核形成的影响。结果表明:纳他霉素及多菌灵对灰葡萄孢不同生育阶段菌体的抑制作用随温度降低而有不同程度增强;分生孢子对药剂最为敏感;温度对药剂对菌丝毒力的影响最显著;多菌灵对菌株不同发育阶段的抑制活性均高于纳他霉素。供试药剂对菌株产孢时间和菌核产生时间无显著影响,但多菌灵可显著刺激菌株产孢和菌核形成。     

单种或多种寄主植物混合共存对B型烟粉虱成虫的影响

为探究B型烟粉虱Bemisia tabaci(Gennadius)成虫对寄主植物多样性的适应性,采用生态测定和生化方法,比较了油菜、棉花、番茄、黄瓜4种寄主植物同时存在与单种寄主植物存在时对B型烟粉虱存活率、产卵量、总蛋白、海藻糖、超氧化物歧化酶(superoxide dismutases, SOD)、碱性磷酸酶(alkaline phosphatase, AKP)、海藻糖酶、蔗糖酶、淀粉酶等指标的影响.同时,利用“Y”型嗅觉仪,测定了B型烟粉虱雌成虫对4种寄主混合共存和单独存在时的行为反应.结果表明,与单种寄主植物相比,4种寄主植物混合共存时,烟粉虱9 d时存活率显著降低,为(64.0±3.8)%,总产卵量为907±52.5粒,大于棉花,小于油菜、黄瓜,与番茄无显著差异;海藻糖含量及SOD、AKP、海藻糖酶、蔗糖酶、淀粉酶活性相对增大;行为研究表明4种寄主植物混合共存与单种植物存在时相比,除油菜外,B型烟粉虱雌虫对单种植物选择趋性较强.     

低剂量甲氧虫酰肼对舞毒蛾生长发育的影响

采用药剂短期处理和连续处理,测定了低剂量LC_(10)和LC_(30)甲氧虫酰肼处理舞毒蛾4龄幼虫后,对其各项发育指标、营养指标及各发育阶段形态的影响.结果表明,LC_(10)和LC_(30)剂量甲氧虫酰肼能显著降低舞毒蛾幼虫成活率、化蛹率、6龄虫重及雌蛹重,与对照组相比,LC_(30)剂量处理24 h后,舞毒蛾5龄和6龄幼虫成活率、化蛹率、6龄虫重及雌蛹重明显降低,依次为48.89%、72.62%、62.22%、0.21 g和0.75 g,且LC_(30)剂量对幼虫和蛹的致死性较LC_(10)剂量明显,连续处理较短期处理明显,差异均显著(P<0.05).低剂量甲氧虫酰肼对幼虫营养指标也存在明显影响,LC_(10)剂量能抑制幼虫相对取食量(RCR),LC_(30)剂量能抑制食物利用率(ECI),且两者均能显著抑制幼虫相对生长率(RGR)(P<0.05).同时低剂量甲氧虫酰肼能导致舞毒蛾幼虫畸形,畸形率为62.53%.说明低剂量甲氧虫酰肼可取代高毒农药,用于防治森林鳞翅目害虫.