一株高效氯嘧磺隆降解菌的分离鉴定及其降解机理初探

消除农业生产中除草剂残留是现代农业绿色发展的关键,为发掘更多磺酰脲类除草剂高效降解微生物资源,系统阐述氯嘧磺隆的微生物降解途径。以氯嘧磺隆为唯一氮源,从某磺酰脲类除草剂生产厂废水处理活性污泥中分离出的高效氯嘧磺隆降解菌LAM2021。生理生化特性和16S rRNA基因序列比对分析结果表明,该菌株属小坂菌属(Kosakonia sp.)。单因素试验结果经RSM优化后,菌株LAM2021在无机盐培养基中对50 mg/L氯嘧磺隆的最佳降解条件为:接种量5%、培养温度30℃、pH 6.0,11 h后降解率可达94.6%。利用高效液相色谱(HPLC)对接菌后降解体系内代谢产生的酸类物质进行分离与鉴定,结果表明产物主要为柠檬酸。推测菌株LAM2021受高浓度氯嘧磺隆胁迫,利用葡萄糖产生柠檬酸,通过降低环境pH使氯嘧磺隆发生水解,从而解除其胁迫。从菌株全基因组信息中发现有参与氯嘧磺隆降解的酯酶编码基因。采用液相色谱-质谱联用(LC-MS)对菌株LAM2021与氯嘧磺隆混合培养后的代谢产物进行检测与鉴定,共有5种主要物质被检测到。根据氯嘧磺隆的化学结构式和中间代谢产物特征,推测菌株LAM2021降解氯嘧磺隆的代谢途径为:氯嘧磺隆中的脲桥先水解断裂成2-氨基-4-氯-6-甲基嘧啶和邻甲酸乙酯苯磺酰胺,随后酯键被脱酯断裂成邻甲酸乙酯苯磺酰胺,最后环化为N-醛基糖精。     

Joint Acaricidal Action of Diafenthiuron and Fenbutatin-oxide Against Tetranychus cinnabarinus （Boisduval） （Acari： Tetranychidae）

[Objective]This study was conducted to obtain a new high-efficiency acaricide mixture.[Method]The synergism acaricidal of diafenthiuron and fenbutatin-oxide against carmine spider mite was investigated,and the optimal ratio of both acaricides were determined by means of co-toxicity factors and co-toxicity coefficients（CTC）.[Result]At 24 h post-treatment,the LC50values of diafenthiuron and fenbutatin-oxide against T.cinnabarinus female adults were 154.67 and 93.26 mg/L,respectively,and the synergistic mass ratios of diafenthiuron and fenbutatin-oxide ranged from 1：0.06 to 1：0.87,and the optimal diafenthiuron-to-fenbutatin-oxide ratio was 1：0.39 with the LC50and CTC of 67.87 mg/L and 188.93（CTC significantly above 100 strongly indicated synergism）,respectively,and the toxicity relative to diafenthiuron and fenbutatin-oxide was 2.28 and 1.37 times,respectively.[Conclusion]The joint acaricidal action of diafenthiuron and fenbutatin-oxide strongly indicates synergism.These findings proved scientific theoretical basis for mixing diafenthiuron and fenbutatin-oxide to control spider mites and developing a new synergisic acaricide.     

Hydrolytic Enzyme Inhibitors and Necrotic Reactions in Potato Leaves Reduce Reproductive Success of Colorado Potato Beetle

In field and laboratory conditions the reproductive potential （survival at different stages of development） of the Colorado potato beetle has been measured, the dependence of the parameters of insects fertility on varietal features of the feed has been investigated, the food activity of the representatives of insects from four areas of the Southern Urals has been measured, the intensity and time of hypersensitivity reactions on potato leaves has been defined. In laboratory experiments, the level of activity of hydrolytic enzymes in insects and the level of activity of these enzymes inhibitors in the leaves of three potato varieties differing in their resistance to the Colorado potato beetle have been determined. The results show that the insects-representatives of different samples have different food activity in relation to different potato varieties. High mortality rates were revealed at feeding with leaves of potato of the Bashkir variety characterized by a high level of hydrolases inhibitors and relatively rapid development of necrotic reactions after the appearance of eggs laying on the leaves. We suppose that the neerogenetic barrier appearing in the form of necrosis is the major cause of the fetal mortality of insects. The level of the content of inhibitors inactivating larvae digestive enzymes affects the survival of insects at postembryonic stages. The speed of the necrosis emergence, the level of activity of digestive enzymes inhibitors in potato can be considered as criteria for the selection of breeding material for resistance to the Colorado potato beetle.     

单羰基姜黄素类似物对Ⅱ型糖尿病大鼠非酒精性脂肪肝的治疗作用研究

[目的]研究单羰基姜黄素类似物(代号B06)对Ⅱ型糖尿病大鼠非酒精性脂肪肝糖脂代谢紊乱的影响。[方法]应用高糖高脂饲料喂养,小剂量STZ干扰建立Ⅱ型糖尿病大鼠模型[1],并随机分模型组、A75治疗组、C66治疗组、正常对照组,各组均灌胃治疗12周;检测各组大鼠血生化指标[2]。[结果]单羰基姜黄素类似物能明显改善试验性Ⅱ型糖尿病大鼠的血糖升高,FINS明显低于模型组;肝脏TC、血清TG、TC有明显的降低作用,对血清HDL有明显的升高作用,有统计学意义;[结论]单羰基姜黄素类似物对Ⅱ型糖尿病大鼠非酒精性脂肪肝有一定的治疗作用。     

Soil Organic Carbon,Black Carbon,and Enzyme Activity Under Long- Term Fertilization

The present study aims to understand the effects of long-term fertilization on soil organic carbon （SOC）, black carbon （BC）, enzyme activity, and the relationships among these parameters. Paddy field was continuously fertilized over 30 yr with nine different fertilizer treatments including N, P, K, NP, NK, NPK, 2NPK （two-fold NPK）, NPK＋manure （NPKM）, and CK （no fertilization）, N, 90 kg urea-N ha^-1 yr^-1; P, 45 kg triple superphosphate-P205 ha^-1 yr^-1; K, 75 kg potassium chloride-K20 ha^-1 yr^-1; and pig manure, 22 500 kg ha^-1 yr^-1. Soil samples were collected and determined for SOC, BC content, and enzyme activity. The results showed that the SOC in the NPKM treatment was significantly higher than those in the K, P, and CK treatments. The lowest SOC content was found in the CK treatment. SOC content was similar in the N, NP, NK, NPK, 2NPK, and NPKM treatments. There was no significant difference in BC content among different treatments. The BC-to-SOC ratios （BC/SOC） ranged from 0.50 to 0.63, suggesting that BC might originate from the same source. Regarding enzyme activity, NPK treatment had higher urease activity than NPKM treatment. The urease activity of NPKM treatment was significantly higher than that of 2NPK, NP, N, P, K, CK, and NPKM treatment which produced higher activities of acid phosphatase, catalase, and invertase than all other treatments. Our results indicated that long-term fertilization did not significantly affect BC content. Concurrent application of manure and mineral fertilizers increased SOC content and significantly enhanced soil enzyme activities. Correlation analysis showed that catalase activity was significantly associated with invertase activity, but SOC, BC, and enzyme activity levels were not significantly correlated with one another. No significant correlations were observed between BC and soil enzymes. It is unknown whether soil enzymes play a role in the decomposition of BC.     

不同授粉方式对丝瓜产量及品质的影响

为了筛选适合海南冬季丝瓜的授粉方式,以泰国丝瓜为试验对象,研究了不同授粉方式对丝瓜座果率 果实性状产量及品质的影响,结果表明院与其他授粉方式相比氯吡脲授粉能极显著提高丝瓜座果率可达97%并 能极显著提高丝瓜产量,比对照高31.7%且对丝瓜品质无影响。     

三种优质肥料

肥恋田该肥具有以下特点：（1）通过脲酶抑制剂有效控制土壤脲酶活性45天以上．尿素水解过程从3-5天延长到2l～35天,显著延长肥效期。（2）利用氨稳定剂减少铵态氮的挥发损失和NH3浓度,使作物更安全。（3）通过硝化抑制剂控制硝化过程．使肥料硝态氮高峰期由20天推迟N50天．减少淋溶损失．使养分释放与作物吸收同步。（4）利用抑制剂的协同增效作用,控制土壤中脲酶、亚硝化细菌的活性,使铵态氮、硝态氮释放高峰期共向后推迟50天左右．有效减少追肥次数。     

过氧化脲及尿素配比对水培上海青生长及品质的影响

水培蔬菜中硝酸盐富集及供氧状况是当前水培体系亟待解决的问题.为降低水培上海青Brassica campestris ssp.Chinensis(L.)硝酸盐含量,本研究分别通过部分尿素替代日本园试配方中硝酸盐,以及不同过氧化脲(UHP)与尿素配比的方式,探究减硝增氧对水培叶菜生长及品质的影响.首先以30％、40％、50...     

单嘧磺酯除草剂

<正>由南开大学李正名院士创制的磺酰脲类超高效绿色除草剂———单嘧磺酯,前不久进入产业化实施阶段。据了解,单嘧磺酯除草剂每667平方米有效成分     

小菜蛾对苯甲酰基脲类杀虫剂的抗性现状及治理对策

本文概述了小菜蛾对苯甲酰基脲类杀虫剂的抗性现状，并根据其抗性特点提出５点治理对策。