10%哌虫啶SC拌、浸水稻种子发芽安全性试验简报

对水稻种子进行拌种、浸种是防治水稻苗期飞虱与病毒病传播的重要环节,为探明10%哌虫啶SC对种子发芽安全的剂量,特进行了其拌(浸)种安全性试验,结果表明,在本试验条件下,用10%哌虫啶SC拌种、浸种的安全剂量为2～6g/kg稻种。大面积生产上推荐每kg稻种(干重)用10%哌虫啶SC4g拌(浸)常规粳稻(杂交籼稻)种子,可有效控制水稻苗期飞虱危害与病毒病传播。优先考虑用哌虫啶拌种,以提高药剂利用率。

1%申嗪霉素SC防治茄子黄萎病田间药效试验

以"布利塔"茄子为试材,研究了不同剂量、不同使用方法的1%申嗪霉素SC对茄子黄萎病的防治效果。结果表明:1%申嗪霉素SC对茄子黄萎病有较好的防治效果,各处理区均未对茄子产生药害,而且植株长势旺盛、叶片浓绿、产量增加。1%申嗪霉素SC 3kg/667m2土壤处理后覆盖地膜处理区的效果最好,防效为81.24%,比对照增产22.59%。

20%氯虫苯甲酰胺SC防治水稻1代二化螟效果试验

于2008年进行了20%氯虫苯甲酰胺SC防治水稻1代二化螟效果试验,结果表明,在水稻分蘖盛期用20%氯虫苯甲酰胺SC75ml/hm2防治1代二化螟,速效性及持效性均较高,优于我县长期推广使用的5%氟虫腈SC。

15%硝磺草酮SC防除玉米田杂草应用技术研究

为提高玉米产量水平，笔者于2012年开展了15％硝磺草酮SC防除玉米田杂草的应用技术研究。结果表明，该药剂具有安全性高、作用速度快、杀草谱广等特点，能有效防除玉米田禾本科和阔叶杂草的危害，适宜施药剂量为127．5～150g／hm^2。

Isolation and identifi cation of antimicrobial metabolites from sea anemone-derived fungus Emericella sp.SMA01

Marine symbiotic fungi represent an intriguing source of discovery of novel secondary metabolites with various biological activities.Sea anemones are benthic marine invertebrates,however,the cultivable symbiotic fungi residing in the sea anemones are paid few attentions compared to those derived from their cnidarian counterparts.Here we show the identification of antimicrobial secondary metabolites from the sea anemone-derived symbiotic fungi.Out offive isolated fungal strains,only the strain SMA01 showed strong antimicrobial activities,which was assigned into the genus Emericella based on the morphological characteristics and the ITS sequencing.Media swift from liquid fermentation to solid rice medium presented little influence on its antibacterial activity.A chemical investigation of the ethyl acetate extract of the Emericella sp.SMA01 led to discovery of the primary antibiotic metabolite phenazine-1-carboxylic acid.The IC_(50) values of the phenazine-1-carboxylic acid against Phytophthora capsici,Gibberella zeae,and Verticillium dahliae were determined to be 23.26-53.89μg/mL.To the best of our knowledge,this was the first report of Emericella sp.in sea anemones.The current study may benefit understanding of the defensive chemical interactions between the symbiotic fungi and their host sea anemones.

Las-like quorum-sensing system negatively regulates both pyoluteorin and phenazine-1-carboxylic acid production in Pseudomonas sp. M18

A las-like quorum-sensing system in Pseudomonas sp. M18 was identified, which consisted of lasI and lasR genes encoding LuxI-LuxR type regulator. Several functions of the las system from strain M18 were investigated in this study. The chromosomal inactivation of either lasI or lasR by recombination increased the production of both pyoluteorin (Plt) and phenazine-1-carboxylic acid (PCA) by 4-5 fold and 2-3 fold over that of the wild type strain of M18, respectively. Production of both antibiotics was restored to wild-type levels after in trans complementation with the wild-type lasI or lasR gene. Expression of the translational fusions pltA'-'lacZ and phzA'-'lacZ further confirmed the negative effect of lasI or lasR on both biosynthetic operons, and it was also demonstrated that the las system was related to the ability of swarming motility and the inhibition of cell growth.

H-NS family protein MvaU downregulates phenazine-1-carboxylic acid(PCA)biosynthesis via binding to an AT-rich region within the promoter of the phz2 gene cluster in the rhizobacterium Pseudomonas strain PA1201

Histone-like nucleoid-structuring(H-NS)proteins are key regulators in gene expression silencing and in nucleoid compaction.The H-NS family member proteins MvaU in Pseudomonas aeruginosa are thought to bind the same AT-rich regions of chromosomes and function to coordinate the control of a common set of genes.Here,we explored the molecular mechanism by which MvaU controls PCA biosynthesis in P.aeruginosa PA1201.We present evidence suggesting that MvaU is self-regulated.Deletion of mvaU significantly increased PCA production,and PCA production sharply decreased when mvaU was over-expressed.MvaU transcriptionally repressed phz2 cluster expression and consequently reduced PCA biosynthesis.β-galactosidase assays confirmed that base pairing near the35 box is required when MvaU regulates PCA production in PA1201.Electrophoretic mobility shift assays(EMSA)and additional point mutation analysis demonstrated that MvaU directly bound to an AT-rich motif within the promoter of the phz2 cluster.Chromatin immunoprecipitation(ChIP)analysis also indicated that MvaU directly bound to the P5 region of the phz2 cluster promoter.MvaU repression of PCA biosynthesis was independent of QscR and OxyR in PA1201 and neither PCA or H2O2 were the environmental signals that induced mvaU expression.These findings detail a new MvaU-dependent regulatory pathway of PCA biosynthesis in PA1201 and provide a foundation to increase PCA fermentation titer by genetic engineering.

噁嗪草酮与五氟磺草胺或双草醚混用对水稻机插秧田杂草的防效及水稻的安全性

通过田间试验测定了1%噁嗪草酮悬浮剂(SC)与25 g/L五氟磺草胺可分散油悬浮剂(OD)或10%双草醚悬浮剂(SC)桶混使用对机插秧稻田杂草的防效及水稻的安全性。结果表明:1%噁嗪草酮SC 250、300、350 m L/667 m^2与25 g/L五氟磺草胺OD 80 m L/667 m^2混用,1%噁嗪草酮SC 350 m L/667 m^2与10%双草醚SC 10 m L/667 m^2混用,在水稻移栽后7 d毒土撒施及移栽后13 d茎叶喷雾施用对稗属杂草、千金子、鸭舌草、耳叶水苋、异型莎草等杂草的防效均达91%以上,优于对照移栽前2 d 35%丙草胺·苄嘧磺隆可湿性粉剂(WP)80 g/667 m^2毒土撒施+移栽后7 d 50%苯噻酰草胺·苄嘧磺隆WP 75 g/667 m^2毒土撒施处理、移栽后20 d 60 g/L五氟磺草胺·氰氟草酯OD 100 m L/667 m^2茎叶喷雾处理,移栽后7 d施药处理对杂草的防效高于移栽后13 d施药处理。1%噁嗪草酮SC 250、300、350 m L/667 m^2与25 g/L五氟磺草胺OD 80 m L/667 m^2或10%双草醚SC 10 m L/667 m^2桶混在水稻移栽后7 d或13 d处理对机插秧水稻安全。

Electron transfer mediator PCN secreted by aerobic marine Pseudomonas aeruginosa accelerates microbiologically influenced corrosion of TC4 titanium alloy

Titanium alloys possess excellent corrosion resistance in marine environments,thus the possibility of their corrosion caused by marine microorganisms is neglected.In this work,microbiologically influenced corrosion(MIC)of TC4 titanium alloy caused by marine Pseudomonas aeruginosa was investigated through electrochemical and surface characterizations during a 14-day immersion test.Results revealed that the unstable surface caused by P.aeruginosa resulted in exposure of Ti_(2)O_(3) and severe pitting corrosion with maximum pit depth of 5.7μm after 14 days of incubation.Phenazine-1-carboxylate(PCN),secreted by P.aeruginosa,promoted extracellular electron transfer(EET)and accelerated corrosion.Deletion of the phzH gene,which codes for the enzyme that catalyzes PCN production,from the P.aeruginosa genome,resulted in significantly decreased rates of corrosion.These results demonstrate that TC4 titanium alloy is not immune to marine MIC,and EET contributes to the corrosion of TC4 titanium alloy caused by P.aeruginosa.