Phlegrean Fields is a large volcanic area situated southwest of Naples (Italy), including both cave and thermoacidic habitats. These extreme environments host the genus Cyanidium; the species C. chilense represents a common phototrophic microorganism living in anthropogenic caves. With a view to provide a comprehensive characterization for a correct taxonomic classification, morpho‐ultrastructural investigations of C. chilense from Sybil's cave (Phlegren Fields) was herein carried out and compared with the thermoacidophilic C. caldarium. The biofilm was also analyzed to define the role of C. chilense in the establishment of a biofilm within cave environments. Despite the peculiar ecological and molecular divergences, C. chilense and C. caldarium shared all the main diacritic features, suggesting morphological convergence within the genus; cytological identity was found among C. chilense strains geographically distant and adapted to different substrates, such as the porous yellow tuff of Sybil cave, and calcyte, magnesite and basaltic rocks from other caves. C. chilense is generally dominant in all biofilms, developing monospecific islets, developing both superficially or between fungal hyphae and coccoid cyanobacteria. Extracellular polymeric substances (EPS) were recorded in C. chilense biofilms from Sybil cave, confirming the role of EPS in facilitating cells adhesion to the surface, creating a cohesive network of interconnecting biofilm cells.

中文翻译：

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Cyanidium chilense（Cyanidiophyceae，Rhodophyta）来自意大利库马考古遗址的凝灰岩

Phlegrean Fields 是位于那不勒斯（意大利）西南部的一个大型火山区，包括洞穴和热酸性栖息地。这些极端环境中寄居着 Cyanidium 属；C. chilense 物种代表了一种生活在人为洞穴中的常见光养微生物。为了为正确的分类学分类提供全面的表征，本文对来自 Sybil's Cave (Phlegren Fields) 的 C. chilense 进行了形态超微结构研究，并与嗜热嗜酸的 C. caldarium 进行了比较。还对生物膜进行了分析，以确定 C. chilense 在洞穴环境中建立生物膜中的作用。尽管存在特殊的生态和分子差异，C. chilense 和 C. caldarium 共享所有主要的变音特征，表明该属内的形态趋同。在地理上相距遥远并适应不同基质的 C. chilense 菌株中发现了细胞学同一性，例如 Sybil 洞穴的多孔黄色凝灰岩，以及来自其他洞穴的方解石、菱镁矿和玄武岩。C. chilense 通常在所有生物膜中占主导地位，发育单特异性胰岛，在表面发育或在真菌菌丝和球状蓝细菌之间发育。胞外聚合物 (EPS) 被记录在来自 Sybil 洞穴的 C. chilense 生物膜中，证实了 EPS 在促进细胞粘附到表面、创建互连生物膜细胞的内聚网络中的作用。chilense 通常在所有生物膜中占主导地位，发育单特异性胰岛，在表面发育或在真菌菌丝和球状蓝细菌之间发育。胞外聚合物 (EPS) 被记录在来自 Sybil 洞穴的 C. chilense 生物膜中，证实了 EPS 在促进细胞粘附到表面、创建互连生物膜细胞的内聚网络中的作用。chilense 通常在所有生物膜中占主导地位，发育单特异性胰岛，在表面发育或在真菌菌丝和球状蓝细菌之间发育。胞外聚合物 (EPS) 被记录在来自 Sybil 洞穴的 C. chilense 生物膜中，证实了 EPS 在促进细胞粘附到表面、创建互连生物膜细胞的内聚网络中的作用。