• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Characterization of unusual Gymnamoebae isolated from the marine environment.
【24h】

Characterization of unusual Gymnamoebae isolated from the marine environment.

机译：与海洋环境隔离的不寻常的裸藻科动物的特征。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Amoebae are important heterotrophic protists (protozoa) and this study focuses on three unusual forms from the marine environment. Amoebae are ubiquitous and play an important role as consumers in microbial communities. A common coastal ctenophore (Mnemiopsis sp.) is known to harbor an undescribed naked amoeba on the comb plate surface. The nature of the symbiotic association is unknown although electron microscopy suggests these micrograzers are degrading comb plates (Moss et al., 2001). A second amoeba isolate from mangrove waters is new to science by virtue of its distinctive trophic form that does not conform to any described species. A third isolate, Acanthamoeba spp. is unusual because it was isolated from offshore marine waters despite the fact it is normally found in soil. On rare occasions acanthamoebae invade the cornea and cause Amoebic Keratitis (AK). Characterization of these amoebae involved characterizing three important diagnostic features including morphology (size, form and locomotion), physiology (salinity tolerance) and molecular analysis. Salinity tolerance experiments (0g/l to 50g/l) were conducted to better understand the origin of the isolates while the molecular analysis was conducted with an aim to determine phylogeny of the isolates. The Acanthamoeba marine isolate was compared to non-marine strains isolated from other 'unusual' environments including chlorinated tap water, acidic soil (pH4) and marine fish scale mucus. These were included to determine their genotypes and to explore a suggested possible link between survivability in extreme habitats and pathogenicity (Booton et al., 2004). Characterizing the ctenophore amoeba included all three diagnostic features while studies on the second amoeba isolate involved physiological studies (salinity tolerance) and molecular analysis (ribotyping) based on small subunit (SSU) ribosomal RNA gene (Medlin et al., 1988 Smirnov et al., 2007). Studies on acanthamoebae included physiological studies and genotyping based on the 18S small subunit ribosomal RNA gene (Booton et al., 2004). The ctenophore amoeba had an optimum generation time at 10g/l salt (7.9 hours) suggesting that this is an estuarine amoeba although cells survived up to 50g/l. The amoeba from mangrove waters had its optimum generation time at 20g/l (34 hours) and amoebae survived up to 50g/l. The "marine" Acanthamoeba grew best at 15g/l salt suggesting that this may be an unusual strain with a unique genotype. Phylogenetic analyses showed that the marine strain was a T3 designate while tap water strains and acid tolerant acanthamoebae were T4 strains. The acid tolerant Acanthamoeba strain closely resembled A. castellanii previously associated with AK infections (98% bootstrap value 0.2% dissimilarity). Acanthamoeba strain from fish mucus closely resembled T5 designates (78% bootstrap value 5% dissimilarity). There was no notable trend seen with acanthamoebae genotypes and association with "extreme" environments. However, a T3 Acanthamoeba designate has previously been reported to tolerate salinity as high as 32g/l (Sawyer 1970, 1971). Interestingly, all three unusual amoebae isolates showed optimum growth between 10g/l and 20g/l indicating that amoebae, in general, may prefer this low salinity to save on energetic costs involved in expelling water via their contractile vacuoles.
机译：变形虫是重要的异养生物（原生动物），这项研究集中于海洋环境中的三种不同形式。变形虫无处不在，并在微生物群落中作为消费者发挥重要作用。已知一种常见的沿海c虫（Mnemiopsis sp。）在梳板表面上藏有未描述的裸变形虫。尽管电子显微镜显示这些微掠物正在使梳状板降解，但共生缔合的性质尚不清楚（Moss等，2001）。从红树林水体分离出的第二个变形虫，由于其独特的营养形式，不符合任何已描述的物种，因此对科学来说是新事物。第三分离株，棘阿米巴属种。这是不寻常的，因为尽管它通常在土壤中发现，但它还是与近海海水隔离开来。极少数情况下棘皮虫侵入角膜并引起阿米巴性角膜炎（AK）。这些变形虫的表征涉及表征三个重要的诊断特征，包括形态（大小，形式和运动），生理（耐盐度）和分子分析。进行盐度耐受性实验（0g / l至50g / l），以更好地了解分离物的起源，同时进行分子分析，以确定分离物的系统发育。将棘阿米巴海洋分离株与从其他“不寻常”环境（包括氯化自来水，酸性土壤（pH4）和海洋鱼鳞粘液）分离的非海洋菌株进行了比较。这些被包括在内以确定它们的基因型，并探索在极端生境中的生存能力与致病性之间可能存在的联系（Booton et al。，2004）。表征变形虫的变形虫包括所有三个诊断特征，而第二个变形虫的研究则涉及基于小亚基（SSU）核糖体RNA基因的生理研究（盐度耐受性）和分子分析（核糖体分型）（Medlin等人，1988 Smirnov等人。 ，2007）。棘皮科的研究包括基于18S小亚基核糖体RNA基因的生理学研究和基因分型（Booton等，2004）。 ctenophore变形虫的最佳生成时间为10g / l盐（7.9小时），这表明这是一种河口变形虫，尽管细胞存活至50g / l。来自红树林水的变形虫的最佳生成时间为20g / l（34小时），变形虫存活至50g / l。 “海洋”棘形棘藻以15g / l的盐分生长最快，表明这可能是具有独特基因型的不寻常菌株。系统发育分析表明，海洋菌株为T3菌株，自来水菌株和耐酸棘阿米巴杆菌为T4菌株。耐酸棘阿米巴菌株与先前与AK感染相关的卡氏棘孢菌（A. castellanii）非常相似（98％的自举值0.2％相异）。鱼粘液中的棘阿米巴菌株与T5命名非常相似（78％的自举值5％的相似性）。棘阿米巴的基因型和与“极端”环境的关联没有发现明显的趋势。但是，以前有报道称T3棘阿米巴可以耐受高达32g / l的盐度（Sawyer 1970，1971）。有趣的是，所有三种不常见的变形虫都表现出最佳的生长，介于10g / l和20g / l之间，这表明变形虫通常更喜欢这种低盐度，以节省通过收缩性液泡排出水的高能成本。

著录项

  • 作者

    Mbugua, Margaret Wacera.;

  • 作者单位

    Marshall University.;

  • 授予单位 Marshall University.;
  • 学科 Biology Microbiology.Biology Oceanography.
  • 学位 M.S.
  • 年度 2008
  • 页码 139 p.
  • 总页数 139
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 植物学;
  • 关键词

  • 入库时间 2022-08-17 11:39:14

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号