Programa de Pós-Graduação em Meio Ambiente e Recursos Hídricos, Instituto de Recursos Naturais, Universidade Federal de Itajubá (UNIFEI), Minas Gerais, Brazil.
Mol Biol Rep. 2024 Sep 9;51(1):967. doi: 10.1007/s11033-024-09908-5.
Protists are diverse single-celled eukaryotes found in various habitats. They exhibit a wide range of forms and functions, representing a significant portion of the eukaryotic tree of life, which also includes animals, plants, and fungi. Due to their high sensitivity to environmental changes, these organisms are widely used as biological indicators of organic pollution.
We investigated the molecular diversity of ciliate protists at seven strategic points along the Sapucaí River (Itajubá, Minas Gerais State, Brazil), to assess the impact of urban pollution on the richness, abundance, and diversity indexes of these communities. For each sampling point, values of physicochemical parameters were also recorded. DNA sequences were obtained by high-throughput sequencing (HTS) and analyzed using the V4 18S-rRNA molecular marker, employing the DNA metabarcoding method. We recorded 125 ciliate taxonomic units (OTUs), with nearly 80% corresponding to the classes Spirotrichea, Oligohymenophorea, and Litostomatea. At the genus level, 54 OTUs (43.2%) were identified, spanning 28 genera.
The composition of ciliates varied significantly along the river's course, from upstream to downstream of Itajubá city. Samples collected from the urban area displayed the lowest richness and diversity, corroborating the influence of the pollution gradient on these communities. The physicochemical parameters showed little variation among the samples and were not linked to the observed changes in ciliate communities, revealing that these organisms are strongly affected by environmental changes and respond more sensitively to these disturbances than physicochemical parameters, emphasizing their potential as bioindicators.
原生动物是存在于各种生境中的多样化单细胞真核生物。它们表现出广泛的形态和功能，代表了真核生物生命树的重要部分，其中还包括动物、植物和真菌。由于其对环境变化高度敏感，这些生物被广泛用作有机污染的生物指标。
我们在巴西米纳斯吉拉斯州伊塔茹巴市的萨普卡伊河沿七个战略点调查了纤毛虫原生动物的分子多样性，以评估城市污染对这些群落丰富度、丰度和多样性指数的影响。对于每个采样点，还记录了物理化学参数的值。通过高通量测序 (HTS) 获取 DNA 序列，并使用 V4 18S-rRNA 分子标记，采用 DNA 宏条形码方法进行分析。我们记录了 125 个纤毛虫分类单元 (OTUs)，其中近 80%对应于旋毛目、寡膜纤毛虫和履纤目类群。在属水平上，鉴定出 54 个 OTUs（43.2%），涵盖 28 个属。
从伊塔茹巴市上游到下游，纤毛虫的组成沿河流的过程发生了显著变化。从城市地区采集的样本显示出最低的丰富度和多样性，证实了污染梯度对这些群落的影响。样本之间的物理化学参数变化不大，与观察到的纤毛虫群落变化无关，这表明这些生物受到环境变化的强烈影响，比物理化学参数更敏感地响应这些干扰，强调了它们作为生物指标的潜力。
