Archives of Microbiology

, Volume 177, Issue 5, pp 361–370 | Cite as

Polyphasic characterization of benthic, moderately halophilic, moderately thermophilic cyanobacteria with very thin trichomes and the proposal of Halomicronema excentricum gen. nov., sp. nov.

  • Raeid M. Abed
  • Ferran Garcia-Pichel
  • Mariona Hernández-Mariné
Original Paper


A new genus of moderately halophilic, moderately halotolerant and moderately thermophilic cyanobacteria with very thin trichomes is described. The four strains included in this genus were isolated from benthic microbial mats in a man-made hypersaline pond. Trichomes were around 1 µm thick, with small constrictions at the cross-walls and diffluent colorless sheaths. Thylakoids were parallel to the cell wall, but thylakoids and nucleoid were often excentrically arranged within the cytoplasm with respect to the main trichome axis. Strains grew at between 3.2 and 12–15% (w/v) salinity with optima between 3.2 and 12%. They showed lower temperature limits around 20 °C and upper limits between 45 and 50 °C, with optima between 28 and 45–50 °C. Carotenoid and mycosporine amino-acid complements were identical among strains. Phylogenetic analyses based on 16S rRNA gene sequence showed that all strains were closely related (99% or higher similarity) and distantly related to other cyanobacteria (91% or lower similarity). We propose the new genus and species Halomicronema excentricum for these strains. The type strain is TFEP1.

Microbial mats Hypersaline environments Phormidium, Leptolyngbya Polyphasic taxonomy Halotolerance 16S rRNA Phylogeny Halomicronema Carotenoids Thermotolerance 


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Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Raeid M. Abed
    • 1
  • Ferran Garcia-Pichel
    • 2
  • Mariona Hernández-Mariné
    • 3
  1. 1.Max-Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany
  2. 2.Microbiology Department, Arizona State University, PO Box 872701, Tempe, AZ 85287-2701, USA
  3. 3.Unitat de Botànica, Facultat de Farmàcia, Universitat de Barcelona, Av Joan XXIII s/n, 08028, Spain

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