纯化的苏云金杆菌00-50-5晶体和芽孢对甘蓝尺蠖的杀虫活性

苏云金杆菌(Bacillus thuringiensis,Bt)00-50-5 菌株可以高效地杀死多种鳞翅目昆虫害虫。为了深入研究该菌的治病机理和作用方式,首先需要分离和纯化晶体和孢子,研究它们的杀虫活性。本研究用纯化后的00-50-5菌株晶体和芽孢,比较它们对昆虫甘蓝尺蠖(Trichoplusia ni)的杀虫活性。初步的活性测定结果证实,在用100 μg/mL浓度处理48 h后,00-50-5菌株纯晶体以及晶体和孢子混合物都能够杀死二龄甘蓝尺蠖幼虫,死亡率达100%,纯芽孢则无毒杀效力。 致死中浓度(LC50)的测定结果表明,Bt 00-50-5菌株纯晶体的杀虫活性(LC50＝0.32 μg/mL)高于晶体和孢子的混合物(LC50＝0.48),然而纯孢子的杀虫活性是非常低的(LC50大于500.00)。因此,00-50-5的晶体主要负责引起幼虫的死亡。     

共生菌毒素对亚洲玉米螟和玉米小斑菌杀虫抑菌活性的测定

利用从全国采集的土样中收集到的28个品系的昆虫病原线虫,分离并筛选出28株高毒力共生菌菌株,对高毒力菌株的杀虫毒素进行初步提取,并以亚洲玉米螟和玉米小斑菌作为供试昆虫和供试真菌,对其杀虫抑菌活性进行测定。结果表明：共生菌毒素对两种病虫害均有一定的胃毒活性和抑菌作用,其中菌株5-5B毒素的杀虫抑菌活性最为明显,处理后120 h对亚洲玉米螟的平均校正死亡率为43.70%,抑菌圈直径为34.00 mm。     

多虫清防治棉蚜棉铃虫药效试验

多虫清(Polytrin)系瑞士汽巴-嘉基有限公司农药部经长期研究,筛选出来的一种有机磷与拟除虫菊酯复配的新型广谱杀虫剂。其有效组分为氯氰菊酯和克虫磷(Pro-fenofos),因而具有综合杀虫活性,并可克服害虫由于药剂的单一使用,产生的抗药性。1990～1991年对该药剂进行了防治抗性棉蚜、棉铃虫试验,获得了良好的效果。     

共生菌对两种玉米病虫害杀虫抑菌活性的测定

利用40株昆虫病原线虫共生菌菌株,以亚洲玉米螟和玉米小斑病菌作为供试昆虫和供试真菌,对其杀虫抑菌活性进行测定。结果表明,共生菌发酵液对两种病虫害均有一定的活性。其中菌株A24-2的杀虫抑菌活性最为明显,处理后120h对亚洲玉米螟的平均校正死亡率为44.25%,抑菌圈大小为15.00mm。     

转单双价基因抗虫棉的抗虫性和产量性状研究简报

为了减缓棉铃虫对转 Bt基因抗虫棉产生抗性 ,延长转基因抗虫棉在生产中的使用年限 ,扩大杀虫谱 ,国内外相继开展了转双价基因抗虫棉的研究工作。目前 ,我国已转育成功 Bt和 Cp TI双价基因抗虫棉。2 0 0 1年在辽宁省经作所对转单双价基因抗虫棉的抗虫性和产量性状进行了比较试验。1试验基本情况供试品种为 s GK32 1 ( Bt+Cp TI)早熟系 ,美国抗虫棉 33B( Bt)和非抗虫棉辽棉 1 5号( CK)。1 .1室内棉铃虫幼虫抗虫性试验。在二代棉铃虫发生期 ( 7月 7～ 1 2日 ) ,分别用嫩尖、幼蕾 (直径 1 cm大小 )和嫩叶 (顶尖展开第三、四片真叶 ) ,7月 …     

苏云金芽孢杆菌的概况及其研究进展

苏云金芽孢杆菌(Bacillus thuringiensis,Bt)杀虫剂是对人和环境友好的安全型细菌杀虫剂。目前Bt杀虫剂已被广泛应用,但因使用剂量较大,导致防治害虫时费用过高。若在生物防治中使用超高效的细菌杀虫剂,就可降低其使用剂量。Bt 00-50-5菌株是从美国引进的高效杀虫菌株,其晶体蛋白的特征分析尚未完成,其毒素的作用机理研究也未进行。本项目即将开展如下研究：(1)先用具有特异性杀虫功能的Bt 00-50-5菌株进行发酵,继续完成对防治中国害虫防治效果的评价;再分析细菌的编码杀虫毒素基因和毒素     

“一日两次施药法”防治棉铃虫技术

1诱虫　在上午每 667m2用 2 .5%进口敌杀死乳油 1 3～ 1 5ml,兑水 1 5kg进行叶面快速喷雾。喷过敌杀死后 ,隐蔽在花、蕾、铃、叶处的棉铃虫 ,闻到敌杀死的药味后 ,就爬到叶面上 ,呈半中毒状态挣扎。2杀虫　下午趁棉铃虫在叶面上 ,且又半死半活 ,可采用复配农药猛攻狠打。方法是 :667m2用进口功夫乳油 65～ 70 ml加 2 0 %三唑磷乳油 (浙江新农化工有限公司生产 ) 2 2 5～ 2 50 ml兑水 1 0 0 kg或用Bt(湖北省农科院化工厂生产 )加 2 0 %三唑磷乳油对准棉株群尖、顶端等嫩叶处正反喷药至见有水滴 ,杀虫杀卵。3主要优点　 ( 1 )对抗性强的高龄…     

8.32%天惠虫灵EC防治棉铃虫效果评价

为明确含植物杀虫成份的8.32 %天惠虫灵EC对棉田棉铃虫的防治效果、安全性及其使用技术,于2 0 0 3年6月进行了防治棉田二代棉铃虫的田间小区试验,取得了较好的效果。1试验概况试验地设在聊城市东昌府区张炉集镇孙坊村,试验田与春茬番茄田毗邻,卵虫量偏多,土壤沙质,棉花为越代自留棉品种,4月2 5日直播,定苗密度每公顷5 .4万株,长势良好,均匀一致,靶标为棉铃虫低龄幼虫。试验期间平均气温2 6.3℃,雨量2 1 .5mm。试验前最后一次施药为6月1 2日,40 %久效磷1 0 0 0倍液。1 .1药剂及处理。8.32 %天惠虫灵EC(武汉天惠生物工程有限公司生产) ;0 .4…     

硫丹用来治理抗性棉虫好

据科学试验结果表明,有机氯杀虫剂35％硫丹乳油(法国罗素·优克福公司提供)对溴氰菊酯抗性棉蚜、棉铃虫有较高的杀虫活性。 1 防治棉蚜每666m~2喷硫丹15～30 ml,1～7天后校正虫口减退率为86.9～98.7％,与氧化乐果相比,相同用量1～3天防效相     

抗虫棉的抗虫性与病虫草害综合防治技术

目前我国生产上应用的抗虫棉,是利用现代生物技术将苏云金杆菌(简称Bt)的杀虫蛋白基因导入棉花植株体内,而产生抗虫作用。1抗虫棉的特性1.1抗虫机理。转Bt基因抗虫棉在棉花整个植株和整个生长季节都能不断产生杀虫蛋白,这种杀虫蛋白遍布植株各个部位,棉铃虫等鳞翅目害虫取食抗虫棉后,其消化系统受到破坏而不能取食,全身软腐,最终死亡。1.2抗虫范围及效果。转Bt基因抗虫棉对棉铃虫、红铃虫等鳞翅目害虫具有较好的抗性。对棉花其它病虫、杂草均无抗性,且抗虫性随着棉花的生长而减弱,在棉花苗期和蕾期杀虫蛋白表达量较高,对二代棉铃虫的抗虫…     

Marine benthic cyanobacteria contain apoptosis-inducing activity synergizing with daunorubicin to kill leukemia cells, but not cardiomyocytes

The potential of marine benthic cyanobacteria as a source of anticancer drug candidates was assessed in a screen for induction of cell death (apoptosis) in acute myeloid leukemia (AML) cells. Of the 41 marine cyanobacterial strains screened, more than half contained cell death-inducing activity. Several strains contained activity against AML cells, but not against non-malignant cells like hepatocytes and cardiomyoblasts. The apoptotic cell death induced by the various strains could be distinguished by the role of caspase activation and sensitivity to the recently detected chemotherapy-resistance-associated prosurvival protein LEDGF/p75. One strain (M44) was particularly promising since its activity counteracted the protective effect of LEDGF/p75 overexpressed in AML cells, acted synergistically with the anthracycline anticancer drug daunorubicin in AML cells, and protected cardiomyoblasts against the toxic effect of anthracyclines. We conclude that culturable benthic marine cyanobacteria from temperate environments provide a promising and hitherto underexploited source for novel antileukemic drugs.     

Toxicity Screening of a Gambierdiscus australes Strain from the Western Mediterranean Sea and Identification of a Novel Maitotoxin Analogue

Dinoflagellate species of the genera Gambierdiscus and Fukuyoa are known to produce ciguatera poisoning-associated toxic compounds, such as ciguatoxins, or other toxins, such as maitotoxins. However, many species and strains remain poorly characterized in areas where they were recently identified, such as the western Mediterranean Sea. In previous studies carried out by our research group, a G. australes strain from the Balearic Islands (Mediterranean Sea) presenting MTX-like activity was characterized by LC-MS/MS and LC-HRMS detecting 44-methyl gambierone and gambieric acids C and D. However, MTX1, which is typically found in some G. australes strains from the Pacific Ocean, was not detected. Therefore, this study focuses on the identification of the compound responsible for the MTX-like toxicity in this strain. The G. australes strain was characterized not only using LC-MS instruments but also N2a-guided HPLC fractionation. Following this approach, several toxic compounds were identified in three fractions by LC-MS/MS and HRMS. A novel MTX analogue, named MTX5, was identified in the most toxic fraction, and 44-methyl gambierone and gambieric acids C and D contributed to the toxicity observed in other fractions of this strain. Thus, G. australes from the Mediterranean Sea produces MTX5 instead of MTX1 in contrast to some strains of the same species from the Pacific Ocean. No CTX precursors were detected, reinforcing the complexity of the identification of CTXs precursors in these regions.     

7株拮抗菌的鉴定及其对香蕉炭疽病的防治作用

为了收集利用香蕉炭疽病的生防菌资源和评价拮抗菌的防病能力,通过培养性状与形态特征观察、生理生化反应和16S r RNA序列特征分析等方法对筛选到的7株拮抗菌进行鉴定,并对其防病作用进行了初步测试。结果表明:菌株Bb7802、Bb7304、Bb7202、Bb7108、Bb7004和Bb5911为短短芽孢杆菌,菌株Bc6301为蜡状芽孢杆菌。人工接种结果表明,菌株Bc6301对香蕉炭疽病的防效最高,为45.94%,其余6株拮抗菌的防效在22.35%~43.29%。     

Isolation of entomopathogenic Bacillus from a biodynamic olive farm and their pathogenicity to lepidopteran and coleopteran insect pests

The occurrence of Bacillus entomopathogenic bacteria on a Tunisian biodynamic farm was determined by examining 75 samples from olive tree (Olea europaea L.) habitats. A total of 40 Bacillus isolates were characterized according to their phenotypic, physiological and biochemical parameters. Isolates of the species Bacillus subtilis, Bacillus mycoides, Brevibacillus brevis, Paenibacillus polymyxa, Bacillus licheniformis, Bacillus sp. (1), Bacillus sp. (2) and a standard strain Btk HD-1 were used separately in feeding bioassays on fresh artificial diet against larvae of lepidopterans Prays oleae (Bernard) and Palpita unionalis (Hübner) and coleopterans Hylesinus oleiperda (F.) and Phloeotribus scarabaeoides (Bernard), which are olive tree pests. Larvae were successfully reared on an artificial diet with 25 g powdered olive tree leaves. Compared to the control data, only Btk and the isolates of B. licheniformis, P. polymyxa and B. brevis were entomopathogenic. Larval mortality assessed 7 days post-treatment showed high mortality rates with Btk to lepidopteran larvae (86.6% for P. oleae and 80.9% for P. unionalis) and low mortality against coleopteran pests. B. brevis isolates showed high mortality rates against P. oleae (up to 67.9%). B. licheniformis isolates caused up to 59.2% larval mortality for P. oleae and 43.6% for P. unionalis. Highest coleopteran mortality was achieved by P. polymyxa isolates (up to 55%). According to the 16S rDNA results, isolates of each of the three entomopathogenic strains were similar. Proteins in the strain supernatants were toxic to P. oleae larvae with LC50 values of 10.0 (B. brevis), 12.5 (B. licheniformis) and 37.6 μg/ml (P. polymyxa). Also, P. polymyxa showed an LC50 of 12.4 mg/l against P. scarabaeoides. Our results suggest that entomopathogenic Bacillus present locally in the biodynamic farm could be used in biological control programmes of olive tree pests.     

Bioprospecting Red Sea Coastal Ecosystems for Culturable Microorganisms and Their Antimicrobial Potential

Microorganisms that inhabit unchartered unique soil such as in the highly saline and hot Red Sea lagoons on the Saudi Arabian coastline, represent untapped sources of potentially new bioactive compounds. In this study, a culture-dependent approach was applied to three types of sediments: mangrove mud (MN), microbial mat (MM), and barren soil (BS), collected from Rabigh harbor lagoon (RHL) and Al-Kharrar lagoon (AKL). The isolated bacteria were evaluated for their potential to produce bioactive compounds. The phylogenetic characterization of 251 bacterial isolates based on the 16S rRNA gene sequencing, supported their assignment to five different phyla: Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Planctomycetes. Fifteen putative novel species were identified based on a 16S rRNA gene sequence similarity to other strain sequences in the NCBI database, being ≤98%. We demonstrate that 49 of the 251 isolates exhibit the potential to produce antimicrobial compounds. Additionally, at least one type of biosynthetic gene sequence, responsible for the synthesis of secondary metabolites, was recovered from 25 of the 49 isolates. Moreover, 10 of the isolates had a growth inhibition effect towards Staphylococcus aureus, Salmonella typhimurium and Pseudomonas syringae. We report the previously unknown antimicrobial activity of B. borstelensis, P. dendritiformis and M. salipaludis against all three indicator pathogens. Our study demonstrates the evidence of diverse cultured microbes associated with the Red Sea harbor/lagoon environments and their potential to produce antimicrobial compounds.     

土壤嗜铁细菌C19的筛选、分子鉴定及其对炭疽菌和镰刀菌的拮抗作用

利用LB液体培养基进行生物富集,采用CAS(Chrome Azurol S)检测平板法.从海南岛橡胶树等作物根际土壤中分离获得43个产嗜铁索细菌菌株.通过室内平板对峙培养法研究其中嗜铁能力较强的菌株C19对12个常见炭疽菌和镰刀菌的拮抗作用,结果表明.该菌株对Fusarium solani等9个菌株有不同程度的拮抗作用,显示该菌株具有较好的生防潜能.扩增菌株C19的16S rDNA序列,序列测定结果显示,该片段长度为1 525 bp,经Blastn搜索进行序列比对.该细菌为洋葱伯克霍尔德氏菌(Burkholderia cepacia).     

海南滨海椰林Bt菌株的筛选与鉴定

以海南省文昌市的滨海椰林为试点,采集144份天然土壤样品,分离出10株苏云金芽孢杆菌,对其中10株菌株进行光学显微镜观察,发现菌体有长菱形、短菱形、方形等晶体类型.对这10株菌进行cry1、cry11、cry2、cry3、cry4、cry5、cry6、cry7、cry8、cry9、cry10类基因的PCR-RFLP鉴定...     

Sponge-Derived Kocuria and Micrococcus spp. as Sources of the New Thiazolyl Peptide Antibiotic Kocurin

Forty four marine actinomycetes of the family Microccocaceae isolated from sponges collected primarily in Florida Keys (USA) were selected from our strain collection to be studied as new sources for the production of bioactive natural products. A 16S rRNA gene based phylogenetic analysis showed that the strains are members of the genera Kocuria and Micrococcus. To assess their biosynthetic potential, the strains were PCR screened for the presence of secondary metabolite genes encoding nonribosomal synthetase (NRPS) and polyketide synthases (PKS). A small extract collection of 528 crude extracts generated from nutritional microfermentation arrays was tested for the production of bioactive secondary metabolites against clinically relevant strains (Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumannii and Candida albicans). Three independent isolates were shown to produce a new anti-MRSA bioactive compound that was identified as kocurin, a new member of the thiazolyl peptide family of antibiotics emphasizing the role of this family as a prolific resource for novel drugs.     

甘蔗褐条病病原菌分离鉴定及其室内毒力的测定

针对海南省不同植蔗区甘蔗褐条病的典型病斑进行分离培养、单孢纯化、形态学观察、致病性检测以及结合r DNA-ITS序列分析鉴定病原菌。分离到的5株病原菌,经回接实验表明,病原菌HT-4致病性最强,能引起与田间病害一致的症状,将菌株HT-4的r DNA-ITS序列在NCBI上进行BLAST比对。结果表明:菌株HT-4与离蠕孢属(Bipolaris)相似性达到99%,结合形态学分析确定该菌是甘蔗褐条病的病原菌。室内毒力实验表明:在7种供试药剂中,50%咪鲜胺锰盐和10%苯醚甲环唑对病原菌抑制效果最好,EC50值分别为4.400 6 mg/L和9.421 1 mg/L。结果为甘蔗褐条病的防控提供科学参考。