Browsing by Author "Léon, Rosa"
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- Antioxidant, antimicrobial, and bioactive potential of two new haloarchaeal strains isolated from Odiel Salterns (Southwest Spain)Publication . Gómez-Villegas, Patricia; Vigara, Javier; Vila, Marta; Varela, João; Barreira, Luísa; Léon, RosaThe need to survive in extreme environments has furnished haloarchaea with a series of components specially adapted to work in such conditions. The possible application of these molecules in the pharmaceutical and industrial fields has received increasing attention; however, many potential bioactivities of haloarchaea are still poorly explored. In this paper, we describe the isolation and identification of two new haloarchaeal strains from the saltern ponds located in the marshlands of the Odiel River, in the southwest of Spain, as well as the in vitro assessment of their antioxidant, antimicrobial, and bioactive properties. The acetone extract obtained from the new isolated Haloarcula strain exhibited the highest antioxidant activity, while the acetone extracts from both isolated strains demonstrated a strong antimicrobial activity, especially against other halophilic microorganisms. Moreover, these extracts showed a remarkable ability to inhibit the enzyme cyclooxygenase-2 and to activate the melanogenic enzyme tyrosinase, indicating their potential against chronic inflammation and skin pigmentation disorders. Finally, the aqueous protein-rich extracts obtained from both haloarchaea exhibited an important inhibitory effect on the activity of the acetylcholinesterase enzyme, involved in the hydrolysis of cholinergic neurotransmitters and related to several neurological diseases.
- Biochemical characterization of the amylase activity from the New Haloarchaeal Strain Haloarcula sp. HS isolated in the Odiel MarshlandsPublication . Gómez-Villegas, Patricia; Vigara, Javier; Romero, Luis; Gotor, Cecilia; Raposo, Sara; Gonçalves, Brígida; Léon, RosaAlpha-amylases are a large family of α,1-4-endo-glycosyl hydrolases distributed in all kingdoms of life. The need for poly-extremotolerant amylases encouraged their search in extreme environments, where archaea become ideal candidates to provide new enzymes that are able to work in the harsh conditions demanded in many industrial applications. In this study, a collection of haloarchaea isolated from Odiel saltern ponds in the southwest of Spain was screened for their amylase activity. The strain that exhibited the highest activity was selected and identified as Haloarcula sp. HS. We demonstrated the existence in both, cellular and extracellular extracts of the new strain, of functional α-amylase activities, which showed to be moderately thermotolerant (optimum around 60 ◦C), extremely halotolerant (optimum over 25% NaCl), and calcium-dependent. The tryptic digestion followed by HPLC-MS/MS analysis of the partially purified cellular and extracellular extracts allowed to identify the sequence of three alpha-amylases, which despite sharing a low sequence identity, exhibited high three-dimensional structure homology, conserving the typical domains and most of the key consensus residues of α-amylases. Moreover, we proved the potential of the extracellular α-amylase from Haloarcula sp. HS to treat bakery wastes under high salinity conditions.