title: Esterase as an enzymatic signature of Geodermatophilaceae adaptability to Sahara desert stones and monuments.
abstract: OBJECTIVE
  To assess esterase profiling of members of Geodermatophilaceae isolated from desert stones and monuments in Tunisia and Egypt.
  
  
  RESULTS
  Members of Geodermatophilaceae family isolated from desert stones and monuments in Tunisia and Egypt were characterized by partial 16S rRNA sequences. Twenty-five strains were clustered in three dissimilar groups of the genera Geodermatophilus (12 strains), Blastococcus (5 strains) and Modestobacter (3 strains). Isolates were also screened and typed based on major groups of esterase hydrolytic activity. Their esterase patterns were determined and compared to those of ten reference strains belonging to Geodermatophilaceae family. Strains exhibited a diverse and complex pattern of electrophoretic esterase bands, and 31 haplotypes were obtained for the 35 investigated strains. Esterases produced by members of Geodermatophilaceae family have an optimal activity around 40 degrees C and at pH 8. Esterases from Geodermatophilus strains display a high resistance to thermal inactivation and alkaline pH and retaining 30 and 20% of activity after heating for 20 min at 120 degrees C and at pH 12, respectively, and were completely inactivated after 30 min at 120 degrees C. Enzyme activity has been strongly activated in the presence of Ca(2+)and Mg(2+) ions and moderately by Zn(2+) and was markedly inhibited by Cu(2+) and Co(2+) ions.
  
  
  CONCLUSIONS
  Geodermatophilaceae isolates share a rich and particular pool of esterase activities that could be directly linked to harsh conditions characterizing their ecological habitat including high level of aridity, temperature, ionic strength and low nutrient availability.
  
  
  CONCLUSIONS
  Esterase could be considered as enzymatic signature that outlines adaptability of Geodermatophilaceae in arid area.
authors.affiliation: Laboratoire Microorganismes & Biomolécules Actives, Département de Biologie, Faculté des Sciences de Tunis, Campus Universitaire, Tunis, Tunisia.
authors.forename: I
authors.initials: I
authors.lastname: Essoussi
authors.forename: F
authors.initials: F
authors.lastname: Ghodhbane-Gtari
authors.forename: H
authors.initials: H
authors.lastname: Amairi
authors.forename: H
authors.initials: H
authors.lastname: Sghaier
authors.forename: A
authors.initials: A
authors.lastname: Jaouani
authors.forename: L
authors.initials: L
authors.lastname: Brusetti
authors.forename: D
authors.initials: D
authors.lastname: Daffonchio
authors.forename: A
authors.initials: A
authors.lastname: Boudabous
authors.forename: M
authors.initials: M
authors.lastname: Gtari
mesh_terms: D000192:Actinomycetales / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D000222:Adaptation, Physiological / Q000235:genetics*; D000352:Africa, Northern; D002413:Cations, Divalent / Q000494:pharmacology; D003889:Desert Climate; D004534:Egypt; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013696:Temperature; D014416:Tunisia
chemical_list: D002413:Cations, Divalent; D012336:RNA, Ribosomal, 16S