Antitumor activity of Actinobacteria isolated in marine sediment from Todos Santos Bay, Baja California, Mexico

Abstract

Resumen.-Se realizó el estudio de la bioactividad de las Actinobacterias cultivables a partir de sedimento marino de la Bahía de Todos Santos, México, y se identificaron mediante las secuencias del gen 16S ARNr. Las cepas bacterianas fueron cultivadas en 1 L de medio líquido A1 y se constató su crecimiento en presencia de agua de mar. Los extractos orgánicos de los cultivos se extrajeron con Amberlita XAD-7 eluida con acetona. Los extractos fueron separados por cromatografía en gel de sílice C-18. Los extractos crudos y las fracciones se probaron contra células de cáncer de colon HCT-116. En total, 26 cepas fueron cultivadas e identificadas, divididas en 10 unidades taxonómicas operacionales (UTOs) con 100% de identidad de sus secuencias, representando tres familias del orden Actinomycetales, pertenecientes a los géneros Streptomyces (77%), Micromonospora (20%) y Nocardia (3%); 6 de éstos UTOs no habían sido reportados previamente. Diecinueve por ciento de los extractos crudos del género Streptomyces mostraron actividad citotóxica en un rango de IC 50 de 69,0 a ≤ 0,076 μg·ml -1 . Las fracciones más activas contenían los compuestos monactin y derivados de pamamicina, los cuales fueron identificados por su peso molecular y sus patrones de fragmentación. Palabras clave: Bacterias marinas, actividad antitumoral, diversidad bacteriana, filogeniaAbstract.-The bioactivity of culturable Actinobacteria from marine sediment of the Todos Santos Bay, Mexico was studied, and bacteria were identified by 16S rRNA gene sequences. The strains were cultured in 1 L of culture media A1 and tested for the effects of seawater on growth. The organic components of cultures were extracted with XAD-7 amberlite and eluted with acetone. The extracts were separated by flash chromatography on C-18 silica gel. The crude extracts and the fractions were tested against colorectal cancer cells HCT-116. In total, twenty six strains were cultured and identified, divided into ten operational taxonomic units (OTUs) with 100% sequence identity, representing 3 families in the order Actinomycetales, belonging to the genus Streptomyces (77%), Micromonospora (20%) and Nocardia (3%); six of those OTUs had not been reported before. Nineteen percent of the crude extracts of the Streptomyces genus showed cytotoxic activity in a range of IC 50 of 69.0 to ≤ 0.076 μg·ml -1 . The most active fractions contained compounds identified by their molecular weight and fragmentation patterns as monactin and pamamycin derivatives.

Anticancer potential of metabolic compounds from marine actinomycetes isolated from Lagos Lagoon sediment

“…Becerril-Espinosa et al. [21] found that 19.2% of actinobacteria isolates possessed anticancer activity, whilst El-Shatoury et al. [22] showed that 17.5% of actinomycetes isolated from the marine environment in Egypt showed anticancer activity.…”

Rare actinobacteria isolated from the hypersaline Ojo de Liebre Lagoon as a source of novel bioactive compounds with biotechnological potential

“…In addition, Becerril et al . (2012) identified a total of 139 actinobacteria strains isolated from the Gulf of California and Todos Santos Bay marine sediments, using six culture media [ 90 ]. The genera Salinispora and Streptomyces were the most abundant genera found by Becerril (2012) with 43 and 31 %, respectively [ 90 ].…”

“…(2012) identified a total of 139 actinobacteria strains isolated from the Gulf of California and Todos Santos Bay marine sediments, using six culture media [ 90 ]. The genera Salinispora and Streptomyces were the most abundant genera found by Becerril (2012) with 43 and 31 %, respectively [ 90 ]. With regards to the genus Salinispora, we expected to recover this genus from the Laguna Ojo de Liebre sediments as there is evidence suggesting this is commonly distributed in tropical and subtropical marine sediments where its growth requirements are met [ 91 ].…”

On the Selective Isolation of Actinobacteria from Different Mexican Ecosystems

“…The study of the Mexican marine ecosystems and their marine resources is still poorly studied. In contrast, the potential of actinobacteria isolated from marine sediments collected in Mexico has been reported [8,[27][28][29] and showed that they produce novel and potent compounds with biological activity. Major European research marine programs have shown the importance to study and protect the marine ecosystem but in Latin America, the efforts of conservation and protection of unique marine Mexican sites are urgently needed.…”