Inhibition of juvenile hormone biosynthesis and methyl farnesoate epoxidase activity by 1,5-disubstituted imidazoles in the cockroach,Diploptera punctata

Seventeen substituted imidazoles were tested as inhibitors of juvenile hormone (JH) III synthesis by cockroach corpora allata in an in-vitro radio-chemical assay. Most of these 1,5-disubstituted imidazoles were highly potent, with IC₅₀ values of less than 100nM. The compounds differed in their ability to cause an accumulation of the precursor methyl farnesoate in the glands. Four of the imidazoles were tested by topical application to previtellogenic adult females, and all caused a significant inhibition of JH synthesis and an accumulation of intraglandular methyl farnesoate for at least three days after treatment. Methyl farnesoate epoxidase activity of homogenates of corpora allata was inhibited by the compounds TH -14 and TH -27. This P450-dependent epoxidase activity was inhibited at less than 10 nM. The results show that the 1,5-disubstituted imidazoles are powerful inhibitors of the last step of juvenile synthesis in this cockroach.     

栽培稻、斑点野生稻、药用野生稻基因组比较分析

以栽培稻总DNA为探针,对栽培稻(AA)自身、斑点野生稻(BB)以及药用野生稻(CC)体细胞染色体进行基因组荧光原位杂交(GISH),并以斑点野生稻总DNA为探针,对自身和药用野生稻体细胞染色体进行基因组荧光原位杂交,以此研究A、B、C 3个基因组型之间的关系.结果显示,A、B、C基因组之间都存在较高的同源性,其中AA与CC之间的信号最强,BB基因组与AA基因组次之,BB基因组与CC基因组的信号最弱.说明A、B、C 3个基因组之间的亲缘关系,A与C最近,B与C最远.     

草鱼肠型点状产气单胞菌双抗夹心ELISA试剂盒的研制

通过对包被单抗和酶标单抗以及抗原最佳工作浓度的优化,建立草鱼肠型点状产气单胞菌双抗夹心ELISA试剂盒检测体系。用分光光度法对检测体系的特异性、稳定性和灵敏度进行测定;用脱脂奶平板法对试剂盒的临床应用进行检测。结果表明,单抗最适稀释液为pH9.4的碳酸盐缓冲液,洗涤液为含φ=0.05%Tween-20的PBS,包被单抗最适体积稀释倍数为1∶800,酶标单抗最适体积稀释倍数为1∶6 000,抗原最佳工作浓度为3×104cfu/mL。试剂盒与肠型点状产气单胞菌有特异性反应,脱脂奶平板法与试剂盒法对草鱼患病检出率基本一致,符合率达90%;试剂盒有很好的储存稳定性,检测灵敏度为7×103cfu/mL。     

山血丹种子萌发特性的初步研究

研究了山血丹果实和种子形态及不同温度、播种基质、GA3和ABA、种子的脱水、室温贮藏对种子萌发的影响.结果表明:种子百粒鲜重为6.34～6.95 g,含水量为51.87％ ～ 52.97％.新鲜种子在15、20、25、30℃条件下均能萌发,温度在25℃和30℃时,萌发率达到92％.在播种深度为3 cm的黄土、蛭石、棕糠、珍珠岩4种基质中,黄土的出苗率最高,其次为棕糠和珍珠岩,而蛭石则几乎不出苗.30～ 90 mg/L的GA3和10～ 60 mg/L ABA对室温贮藏60d的成熟种子的萌发无显著影响.种子经硅胶脱水1 ～3d后,含水量由52％降至18％,其发芽率、发芽指数均有不同程度的降低,常温储藏3、5、12个月后,发芽率显著降低,表明它是一种顽拗性种子.     

Identification and Pathogenicity of Pseudomonas aeruginosa DJ1990 on Tail and Fin Rot Disease in Spotted Snakehead

Tail and fin rot disease (TFRD) is a big issue in the production of spotted snakehead, Channa punctata Bloch. The aims of the present study were to isolate and identify the bacterial pathogen causing TFRD, to detect histopathological changes in tissues (fin, tail, liver, and kidney), and to ascertain the antibiotic sensitivity pattern of the isolate. Out of six bacterial isolates, only the isolate DJ1990 was found to be the causal candidate of TFRD in C. punctata. Identical histopathological changes were detected in tail, fin, liver, and kidney under light and scanning electron microscope in both collected diseased fish and artificially infected fish. The isolate was identified as Pseudomonas aeruginosa strain DJ1990 (National Center for Biotechnology Information Ace. No. KX709967) based on the biochemical characterization tests and 16S rDNA sequence‐based phylogeny analysis. Artificial challenge test demonstrated that the strain DJ1990 was highly virulent (100% mortality at 48 h of postinjection period at the concentration of 1.5 × 10⁷ CFU/g of body weight) for C. punctata. The isolate exhibited sensitivity to the broad‐spectrum antibiotics but was resistant against aztreonum. To the best of our knowledge, this is the first report of P. aeruginosa as a TFRD‐causing candidate in C. punctata.     

鳖疖疮病病原的分离与鉴定

1988年冬到1989年春,我院从某特种水产科研所引进的稚鳘发生了一种新的传染病,病鳖体表形成疖状病灶,暂名为鳖疖疮病。从病鳖的病灶和脏器内分离到两株细菌,经腹腔注射和伤口涂抹能使健康鳖表现出与自然发病相同的病症。两菌株的特性基本一致,被鉴定为点状产气单胞菌点状亚种。     

鲟细菌性败血综合征致病菌的初步研究

从患细菌性败血综合征的杂交鲟(Huso huso♀×Acipenser ruthenus ♂)和达氏鳇(Huso dauricus)的腹水及肾脏中共分离了5株优势菌,经人工回归感染实验证实其中2株细菌XL2-T和HK3-R具有致病性。经ATB细菌鉴定仪鉴定,结果显示:XL2-T为豚鼠气单胞菌(Aeromonas punctata subsp.caviae),HK3-R为类志贺邻单胞菌(Plesiomonas shigelloides)。这2株致病菌的主要特征为:革兰氏染色阴性,杆状,氧化酶阳性,对先锋必、妥布霉素、头孢曲松、头孢噻肟、奈替米星、新霉素等6种药物均高度敏感。     

缢蛏致病菌气单胞菌的分子生物学鉴定

从患病缢蛏（Sinvnovacula constricta）中分离到一株病原菌,暂命名为12#菌。对该菌株的16S rDNA的全序列进行PCR扩增并测序,然后用NCBIBLAST对测序结果进行比对。16S rDNA序列分析表明：12#菌与多株气单胞菌的16S rDNA的同源性均在95%以上。在细菌系统分类学中应归属于气单胞菌属。从构建的系统发育树中可以看出：12#菌与点状产气单胞菌（Aeromonas punctata）共同构成一个分支,且该菌株与点状产气单胞菌（Aeromonas punctata）的16S rDNA同源性达到99%以上,由此可以初步认为该菌为点状产气单胞菌（Aeromonas punctata）。     

少根紫萍对湿地污染水体的修复研究

大量含氮、磷的污水未经处理直接排放到当地河流湖泊等自然水体中,导致湿地环境越来越恶劣,水体富营养化程度加剧,对污染水体的修复已迫在眉睫。本实验以1/5的Hoagland溶液为培养液,设置0 mL·L^-1、20 mL·L^-1、40 mL·L^-1、80 mL·L^-1、160 mL·L^-1五个铜绿微囊藻接种浓度梯度与0 mg·m^-2、100 mg·m^-2、200 mg·m^-2、400 mg·m^-2、800 mg·m^-2 5个少根紫萍接种浓度梯度进行双因素正交试验。结果发现,在0~15 d内,所有少根紫萍接种浓度和铜绿微囊藻接种浓度处理下,水体中总氮(TN)、磷(TP)含量随着接种时间的增加而降低,且铜绿微囊藻和少根紫萍共培养比各自单独培养对污染水体具有更好的修复效果。15d后测定培养液中藻毒素和少根紫萍体内藻毒素含量,结果表明少根紫萍可有效吸收培养液中的藻毒素。以上结果表明,低浓度铜绿微囊藻可促进少根紫萍生长,高浓度铜绿微囊藻抑制少根紫萍生长,少根紫萍可有效吸收培养液中的TN、TP和藻毒素。在铜绿微囊藻浓度为20 mL·L^-1、少根紫萍接种浓度为400 mg·m^-2时,浮萍生长状况最好,对培养液中TN、TP及藻毒素的去除率也达到最高。综上所述,低浓度铜绿微囊藻和100%覆盖率的少根紫萍共培养用于湿地水体修复具有良好的修复效果。     

肠型点状产气单胞菌和鱼害粘球菌原生质体融合的耐药性遗传标记的选择

为了对肠型点状产气单胞菌58－20－9菌株和鱼害粘球菌G4菌株的融合子进行选择鉴定，应用定性和定量药物敏感性试验，对两种蓖原生质体融合的遗传标记进行了筛选，结果表明，这两种细菌对红霉素和庆大霉素交叉耐药，在此基础上，测定了红霉素和庆大霉素在选择培养基中的适用浓度，筛选出肠型点状气单胞菌58－20－9菌株的遗传标记为Em^r（红霉素抗性），鱼害粘球菌G4菌株的遗传标记Gm^r（庆大霉素抗性）。