Analysis of Carotenoids in Haloarchaea Species from Atacama Saline Lakes by High Resolution UHPLC-Q-Orbitrap-Mass Spectrometry: Antioxidant Potential and Biological Effect on Cell Viability.

Haloarchaea are extreme halophilic microorganisms belonging to the domain Archaea, phylum Euryarchaeota, and are producers of interesting antioxidant carotenoid compounds. In this study, four new strains of Haloarcula sp., isolated from saline lakes of the Atacama Desert, are reported and studied by high-resolution mass spectrometry (UHPLC-Q-Orbitrap-MS/MS) for the first time. In addition, determination of the carotenoid pigment profile from the new strains of Haloarcula sp., plus two strains of Halorubrum tebenquichense, and their antioxidant activity by means of several methods is reported. The effect of biomass on cellular viability in skin cell lines was also evaluated by MTT assay. The cholinesterase inhibition capacity of six haloarchaea (Haloarcula sp. ALT-23; Haloarcula sp. TeSe-41; Haloarcula sp. TeSe-51; Haloarcula sp. Te Se-89 and Halorubrum tebenquichense strains TeSe-85 and Te Se-86) is also reported for the first time. AChE inhibition IC50 was 2.96 ± 0.08 µg/mL and BuChE inhibition IC50 was 2.39 ± 0.09 µg/mL for the most active strain, Halorubrum tebenquichense Te Se-85, respectively, which is more active in BuCHe than that of the standard galantamine. Docking calculation showed that carotenoids can exert their inhibitory activity fitting into the enzyme pocket by their halves, in the presence of cholinesterase dimers.

Identification of the Salivary Microbiota of Patients with Oral Cancer in Antofagasta- Chile by Molecular Diagnosis of the 16S rRNA Gene / Identificación de la Microbiota de Saliva de Pacientes con Cáncer Oral de Antofagasta por Diagnóstico Molecular del Gen ARNr 16S

ABSTRACT: Oral cancer, is part of several cancers that affect head and neck, and that according to numerous studies shows an increase of approximately 3-5 % of all cancers. In the last 10 years there has been an increased interest in saliva for its use as a diagnostic tool, due to its easy access, and non-invasive sample collection, unlike blood samples. Studies of metagenomics to the microbiota of oral cancer patients have shown the presence of some groups in greater proportion, it is postulated that they could be used as markers especially in the saliva of these patients. In Antofagasta the number of patients with this type of cancer increases each year. However, there are no studies on the changes that affect the oral microbiota in these patients. The objective of this study is to contribute to the knowledge of the microbiota present in the saliva of patients with oral cancer in the region of Antofagasta, limiting this study exclusively to the group of cultivable anaerobic bacteria. The strains identified are related to the group of Streptococcus mitis / oralis, S. anginosus and S. gordoni, only one strain is grouped near the cluster that includes S. australis and S. parasanguinis. 36.4 % of the molecularly identified isolates, are closely related to the S. anginosus species described in the literature in oropharyngeal tumors. The same percentage is obtained for the taxa related to the cluster that includes S. mitis, proposed in other studies as a diagnostic indicator in subjects with oral squamous cell carcinoma.

RESUMEN: El de cáncer oral, es parte de un grupo de cáncer que afecta cabeza y cuello, y que según demuestran numerosos estudios va en aumento corresponde aproximadamente al 3-5 % de todos los cánceres. En los últimos 10 años la saliva ha aumentado su interés para su uso como diagnóstico debido a su fácil acceso y recolección no invasiva, a diferencia la sangre. Estudios de metagenómica a la microbiota de pacientes con cáncer bucal han demostrado la presencia de algunos grupos en mayor proporción, se postula que podrían ser utilizados como marcadores especialmente en la saliva de estos pacientes. En Antofagasta el número de pacientes con este tipo de cáncer aumenta cada año, sin embargo no hay estudios sobre los cambios que afectan a la microbiota bucal de estos pacientes. El objetivo de este estudio es contribuir al conocimiento de la microbiota presente en la saliva de los pacientes con cáncer bucal en la región de Antofagasta acotando este estudio exclusivamente al grupo de bacterias anaerobias cultivables. Las cepas identificadas se relacionan con el grupo de Streptococcus mitis/oralis, S. anginosus y S. gordoni, sólo una cepa se agrupa cerca del cluster que incluye a S. australis y S. parasanguinis. Un 36,4 % de los aislados identificados molecularmente se relacionan cercanamente a la especie S. anginosus descrita en la bibliografía en tumores orofaríngeos y el mismo porcentaje se obtiene para los taxones relacionados al cluster que agrupa a S. mitis, propuesto en otros estudios como indicador diagnóstico en sujetos con carcinoma oral de células escamosas.

Halomicrobium katesii sp. nov., an extremely halophilic archaeon.

Two extremely halophilic archaea, strains Al-5(T) and K-1, were isolated from Lake Tebenquiche (Atacama Saltern, Chile) and Ezzemoul sabkha (Algeria), respectively. Cells of the two strains were short-rod-shaped and Gram-negative; colonies were orange-pigmented. They grew optimally at 37-40 degrees C and pH 7.0-7.5 in the presence of 25 % (w/v) NaCl. Magnesium was not required. Polar lipid analysis revealed the presence of phosphatidylglycerol and phosphatidylglycerophosphate methyl ester, the absence of phosphatidylglycerosulfate, and the presence of sulfated diglycosyl diether and diether diglycosyl as the sole glycolipids. DNA G+C contents of strains Al-5(T) and K-1 were 52.4 and 52.9 mol% (T(m) method), respectively. 16S rRNA gene sequence comparison with database sequences showed that strains Al-5(T) and K-1 were most closely related to Halomicrobium mukohataei DSM 12286(T) (similarities of 97.5 and 96.9 %, respectively). DNA-DNA hybridization indicated that strains Al-5(T) and K-1 were members of a single species. However, DNA-DNA relatedness to Halomicrobium mukohataei was 55.7+/-2.5 %. A comparative analysis of phenotypic characteristics and DNA-DNA hybridization between the isolates and Halomicrobium mukohataei DSM 12286(T) supported the conclusion that Al-5(T) and K-1 represent a novel species within the genus Halomicrobium, for which the name Halomicrobium katesii sp. nov. is proposed. The type strain is Al-5(T) (=CECT 7257(T)=DSM 19301(T)).

Chromohalobacter nigrandesensis sp. nov., a moderately halophilic, Gram-negative bacterium isolated from Lake Tebenquiche on the Atacama Saltern, Chile.

A total of 52 strains of moderately halophilic bacteria isolated from hypersaline sediment of Lake Tebenquiche on the Atacama Saltern, Chile, were subjected to a taxonomic study. The morphological, physiological, biochemical and nutritional characteristics of the strains matched those described for the genus Chromohalobacter. Cells were Gram-negative, non-spore-forming, rod-shaped and motile. A black pigmentation was produced. One strain, designated LTS-4N(T), grew optimally at 32 degrees C. Growth occurred in media containing 0.5-25% (w/v) total salts; the optimum was 7.5% (w/v) total salts. The pH range for growth was 5-10. The G + C content of the DNA of strain LTS-4N(T) was 59.8 mol%. Analysis of 16S rRNA gene sequence similarity revealed that strain LTS-4N(T) was closely related to Chromohalobacter species; however, DNA-DNA hybridization of representative strain LTS-4N(T) failed to associate the strain with any species of the genus Chromohalobacter with validly published names. Therefore, the name Chromohalobacter nigrandesensis sp. nov. is proposed. The type strain is LTS-4N(T) (= CECT 5315T = DSM 14323T).

Halorubrum tebenquichense sp. nov., a novel halophilic archaeon isolated from the Atacama Saltern, Chile.

A novel extremely halophilic archaeon was isolated from Lake Tebenquiche, situated in the northern part of the Atacama Saltern, Chile. The cells of these micro-organisms were mostly irregularly disc-shaped. They grew in medium containing saturated concentrations of NaCl and did not require magnesium for optimal growth. The polar lipid composition revealed the presence of mannosyl-2-sulfate-(1-4)-glycosyl-archaeol, the main glycolipid of the genus Halorubrum, and two new glycolipids. The G+C content of the DNA was 63.2 mol%. Phylogenetic analysis of the 16S rRNA gene placed strain ALT6-92T within the Halorubrum cluster. The low DNA-DNA hybridization value justified classification in a new species for which the name Halorubrum tebenquichense sp. nov. is proposed. The type strain is ALT6-92T (= CECT 5317T = DSM 14210T).