2株海鞘共附生真菌的次生代谢产物研究

分别对采集自防城港白龙的皱瘤海鞘(Styela plicata)和北海南汅的冠瘤海鞘(Styela canopus)样品的共附生真菌Purpureocillium sp. FBZ-1和Penicillium sp. BNG-1进行研究。通过显微镜观察鉴定其形态,并通过分析生物学特征鉴定其种属。通过对两种真菌的次级代谢产物进行分离和结构鉴定,共分离鉴定28个小分子化合物,从中未发现新的化合物,主要的化合物类型是芳香胺类、生物碱类和二酮哌嗪类,分别为:lumichrome、 1,2,3,4-四氢-β-咔啉-3-羧酸、β-咔啉、环(异亮氨酸-脯氨酸)、环(亮氨酸-羟基脯氨酸)、环(色氨酸-缬氨酸)、环(亮氨酸-脯氨酸)、环(苯丙氨酸-脯氨酸)、环(异亮氨酸-丙氨酸)、环(色氨酸-亮氨酸)、苯乙胺、N-乙酰苯乙胺、吲哚乙胺、N-甲基色胺、N-(4-羟基)丁酰苯乙胺、对羟基苯乙胺、 5,7,4-三羟基异黄酮、 7,4-二羟基异黄酮、 5,7,3,4-三羟基异黄酮、邻苯二甲酸异辛酯、 2,4-N,N-dimethyl-lumichrome、 3,4-二氢-3-甲基-β-咔啉-1-酮、色氨酸、 2-羟基-3-吲哚丙酸、环(缬氨酸-脯氨酸)、环(亮氨酸-丙氨酸)、环(苯丙氨酸-5-甲基-3,4-脱氢脯氨酸)、环(色氨酸-天冬酰胺)。研究结果对利用我国丰富的海鞘及其共附生微生物资源并研究其次级代谢产物结构多样性,发现其中可能含有的结构新颖的化学物质以开发抗菌、抗病毒及抗肿瘤新药,具有十分重要的理论意义和潜在的应用价值。     

海绵共附生放线菌Streptomyces parvulus MA1076的次级代谢产物研究

海绵共附生放线菌是活性次级代谢产物的重要来源,对海绵共附生放线菌Streptomyces parvulus MA1076进行菌株鉴定和化学成分分析.通过16S rDNA序列分析、构建系统发育树进行菌株鉴定;利用硅胶柱色谱、Sephadex LH-20凝胶柱色谱以及半制备高效液相色谱等技术对其发酵产物进行分离和纯化,通过...     

南极钩虾Gammarus sp.肠道共附生菌的分离及Streptomyces xiamenensis YF008的化学成分研究

南极极端生境中蕴含着发掘特殊生物活性天然产物的巨大潜力。对采自南极海域水深6 000 m海区钩虾(Gammarus sp.)的肠道共附生微生物进行分离,并对一株有价值菌株的代谢产物进行研究。采用稀释涂布法进行菌株分离,利用形态学观察及16S rRNA测序进行菌株种属鉴定;综合运用薄层色谱、正相硅胶柱色谱、凝胶柱色谱、反相ODS柱色谱和半制备高效液相(HPLC)等色谱手段分离纯化得到单体化合物,采用波谱学和质谱技术鉴定其化学结构。从钩虾中分离得到17株菌,并将其从分类学角度归属于9个属,其中细菌11株,放线菌6株。从放线菌Streptomyces xiamenensis YF008的发酵产物中分离得到8个单体化合物,分别鉴定为：1(10)E,5E-germacradiene-2,11-diol (1),N-[2-(4-hydroxyphenyl)] ethylacetamide (2),环(L-苯丙氨酸-甘氨酸)(3),环(L-苯丙氨酸-L-丙氨酸)(4),环(D-苯丙氨酸-L-异亮氨酸)(5),环(L-羟脯氨酸-L-苯丙氨酸)(6),环(D-亮氨酸-L-脯氨酸)(7),环(L-苯丙氨酸...     

南极海洋假单胞菌Pseudomonas sp. NJ 013的化学成分

本研究进行了一株南极假单胞菌Pseudomonas sp.NJ-013代谢产物多样性分析、化学成分的分离和结构鉴定,以探讨其产物结构类型。菌株NJ-013甲醇提取物经LC-TOF MS测试分析其代谢产物多样性;还经柱层析和半制备高效液相色谱制备得到4个化学成分;化合物结构经TOF MS、1H-和13C-NMR等波谱学方法和文献数据对照鉴定。假单胞菌Pseudomonas sp.NJ-013的代谢产物主要类型为含氮的生物碱或寡肽类,分离得到的化合物1-4分别鉴定为环(4'-羟基苯丙氨酸-脯氨酸)(1)、环(4-羟基脯氨酸-亮氨酸)(2)、环(4-羟基脯氨酸-苯丙氨酸)(3)、环(异亮氨酸-脯氨酸)(4)。结构较为复杂的微量成分尚待进一步富集、研究。     

Antagonistic activity of marine Streptomyces sp. S073 on pathogenic Vibrio parahaemolyticus

Fisheries Science - Marine Streptomyces sp. isolate S073 was shown to have strong antagonistic activity towards the pathogenic Vibrio parahaemolyticus using the agar diffusion method. The...     

侧孢短芽孢杆菌(Brevibacillus laterosporus)溶藻活性代谢产物对虾池颤藻(Oscillatoria sp.)溶藻效果研究

颤藻(Oscillatoria sp.)为对虾养殖池塘中的一种常见的有害蓝藻。本实验以侧孢短芽孢杆菌(Brevibacillus laterosporus)的除菌体滤液和颤藻为基础,研究各自在不同阶段的溶藻效果,通过测定藻体干重、叶绿素a含量以及藻蓝蛋白含量,探究溶藻效果的最佳作用阶段及其作用机理,为改善对虾养殖水环境提供一定的理论基础。实验结果表明：稳定期和衰亡期的除菌体滤液对颤藻的溶藻效果均影响极显著(P<0.01)：7天后颤藻干重分别减少了51.77%、47.04%,叶绿素a含量分别降低了67.60%、59.13%,藻蓝蛋白含量分别增加了33.51%、30.97%;溶藻细菌除菌体滤液对延滞期的颤藻溶藻效果影响极显著(P<0.01)：7天后颤藻干重减少了63.90%,叶绿素a含量下降了69.72%,藻蓝蛋白含量升高了54.17%。因此,本研究显示侧孢短芽孢杆菌培养至稳定期的除菌体滤液对延滞期颤藻的溶藻效果最好。     

侧孢短芽孢杆菌溶藻活性代谢产物对虾池颤藻的溶藻效果

为改善对虾养殖水环境,研究了不同阶段的侧孢短芽孢杆菌无菌滤液和颤藻对溶藻效果的影响.通过测定溶藻过程中藻体干重、叶绿素a含量以及藻蓝蛋白含量,探究了溶藻效果的最佳作用阶段及其作用机理.结果显示,稳定期和衰亡期的无菌滤液对颤藻的溶藻效果极为显著,7d后颤藻干重分别减少了51.77％、47.04％,叶绿素a含量分别降低了67.60％、59.13％,藻蓝蛋白含量分别增加了33.51％、30.97％;溶藻细菌无菌滤液对延滞期颤藻的溶藻效果极显著,7d后颤藻干重减少了63.90％,叶绿素a含量下降了69.72％,藻蓝蛋白含量升高了54.17％.结果表明,侧孢短芽孢杆菌培养至稳定期的无菌滤液对延滞期颤藻的溶藻效果最好.     

四种常用渔药对胃瘤线虫幼虫的杀灭试验

针对慈溪市饮用水水库底层鱼类相继发生胃瘤线虫危害鱼体生长发育、影响鱼产品质量的情况 ,笔者在调查、取样的基础上 ,选用了鱼苗鱼病防治中四种常用药物 :90 %晶体敌百虫、甲苯咪唑、盐酸左旋咪唑、肠虫清 (阿苯达唑 )等进行幼虫杀灭试验 ,试验方法采用等对数间距法 ,结果表明 :这四种药物对胃瘤线虫幼虫均有杀灭效果 ,其中甲苯咪唑毒性最强 ,90 %晶体敌百虫、盐酸左旋咪唑次之 ,肠虫清毒性最弱。     

Effect of Streptomyces sp. RL8 on the survival of Artemia franciscana nauplii and resistance to Vibrio parahaemolyticus

Fisheries Science - Artemia franciscana nauplii were enriched with Streptomyces sp. RL8 in order to assess its effect on the survival rate of Artemia and its protective effects against Vibrio...     

Infections with Philometra sp. associated with mortalities in wild-hatched captive-raised striped bass, Morone saxatilis (Walbaum)

The striped bass, Morone saxatilis (Walbaum), once represented an important resource for fisheries in the St Lawrence River (Quebec, Canada). A restoration programme, involving captive propagation, was implemented with the objective of restocking the population, which had disappeared in the late 1960s. An unusually high rate of mortality was observed during the winter of 2006 in captive-raised fingerlings that were originally collected from the Miramichi River (New Brunswick, Canada) the previous summer. Post-mortem examinations revealed extensive granulomatous and hyperplastic peritonitis associated with numerous nematodes of the genus Philometra. Given the severity of the lesions, high intensity of infection by Philometra sp. was presumed to be the primary factor in the unusual mortalities reported that winter. Observations suggest that this nematode, which was acquired in the wild, cannot establish itself in a captive environment, most likely because of the absence of the obligate intermediate host. Examination of archived specimens of striped bass showed that this parasite was probably present in the St Lawrence River population prior to its extirpation. Consequently, the introduction of infected fish into this ecosystem should not be a concern. Nevertheless, infection-related mortalities of fingerlings might affect dynamics of wild striped bass populations.     

Candidatus Actinochlamydia pangasiae sp. nov. (Chlamydiales,Actinochlamydiaceae), a bacterium associated with epitheliocystis in Pangasianodon hypophthalmus

Chlamydial infections are recognised as causative agent of epitheliocystis, reported from over 90 fish species. In the present study, the farmed striped catfish Pangasianodon hypophthalmus (14–15 cm, 70–90 g) with a history of cumulative mortality of about 23% during June and July 2015, were brought to the laboratory. The histopathological examination of gills from the affected fish revealed presence of granular basophilic intracellular inclusions, mostly at the base of the interlamellar region and in gill filaments. A concurrent infection with Trichodina spp., Ichthyobodo spp. and Dactylogyrus spp. was observed in the gills. The presence of chlamydial DNA in the gills of affected fish was confirmed by amplification and sequencing of 16S rRNA gene. BLAST‐n analysis of these amplicons revealed maximum similarity (96%) with Candidatus Actinochlamydia clariae. On the basis of phylogenetic analysis, it was inferred that the epitheliocystis agents from striped catfish were novel and belonged to the taxon Ca. Actinochlamydia. It is proposed that epitheliocystis agents from striped catfish will be named as Ca. Actinochlamydia pangasiae. The 16S rRNA gene amplicons from novel chlamydiae were labelled and linked to inclusions by in situ hybridisation. This is the first report of epitheliocystis from India in a new fish host P. hypophthalmus.     

Modulation of gut microbiota associated with abalone Haliotis gigantea by dietary administration of host-derived Pediococcus sp. Ab1

In the present study, we evaluated how dietary administration of host-derived Pediococcus sp. Ab1 has an effect on the abalone gut microbiota using a culture-dependent method and 16S rRNA gene library analysis. The culturable lactic acid bacteria number in the probiotic sample was 10⁵ higher than that in the non-probiotic sample, and we speculate that this significant increase was due to colonization of Ab1 into abalone gut. The result of a culture-dependent method showed that the proportion of Vibrio halioticoli clade, which is known to be a beneficial resident bacterium to abalone, was much higher in the probiotic sample than in the non-probiotic sample. 16S rRNA gene clone sequences revealed that gut microbiota in the probiotic sample was obviously diverse compared to the non-probiotic sample, probably due to improvement of the gut environment by Ab1 colonization. In addition, some beneficial bacteria–like sequences such as V. halioticoli were only found in the probiotic sample. These results suggest that the dietary administration of Ab1 to abalone gut has a great effect on modulation of not only culturable but also unculturable gut microbiota. Our results are useful for future investigations into understanding the effect of probiotics on gut microbiota.