Publication:
A new approach to fight microorganisms: Termite-associated actinobacteria secondary metabolites against pathogenic bacteria and fungi
A new approach to fight microorganisms: Termite-associated actinobacteria secondary metabolites against pathogenic bacteria and fungi
Authors
Quiles Pérez, Christian Joel
Embargoed Until
Advisor
Cafaro, Matías J.
College
College of Arts and Sciences - Sciences
Department
Department of Biology
Degree Level
M.S.
Publisher
Date
2021-05-05
Abstract
Las Actinobacterias son organismos Gram-positivos que tienen un alto contenido de GC en su genoma. Las bacterias de este filo son capaces de producir esporas y compuestos antimicrobianos. Además, estos microorganismos pueden ayudar a degradar varios polisacáridos como quitina, lignocelulosa, celulosa. Algunas Actinobacterias pueden vivir en simbiosis con termitas, lo que puede ayudar a descomponer la materia orgánica y también puede proteger a las termitas inhibiendo el crecimiento de hongos entomopatogénicos. Estudios previos han determinado que las Actinobacterias inhiben el crecimiento de hongos entomopatógenos como Beauveria bassiana y Metarhizium anisopliae. El objetivo de este estudio es determinar metabolitos secundarios que puedan actuar como agentes antimicrobianos aislados de diferentes Actinobacterias asociadas a una termita en Puerto Rico. Se aislaron Actinobacterias de termitas Nasutitermes costalis recolectadas en bosques de manglares en Puerto Rico. Las obreras y las termitas soldado se maceraron en amortiguador de fosfato y el sobrenadante se inoculó en placas de agar de quitina. Después de aislar la bacteria, se enfrentó a tres microorganismos diferentes (Escherichia coli, Staphylococcus aureus y Beauveria bassiana). Se enviaron las Actinobacterias para realizar una extracción sólido-líquido de metabolitos secundarios utilizando solventes orgánicos (acetato de etilo y metanol). El extracto de acetato de etilo se sometió a pruebas químicas para identificar grupos funcionales. Los experimentos de resonancia magnética nuclear (NMR, por sus siglas en inglés) de 1H y 13C mostraron la presencia de aldehídos, ácidos carboxílicos, ésteres y amidas de grupos carbonilo, además de sistemas aromáticos. Las Actinobacterias aisladas de N. costalis tenían la capacidad de inhibir el crecimiento en varios grados de los organismos enfrentados y el extracto de la cepa A4 tiene la capacidad de inhibir el crecimiento de E. coli más que un antibiótico de uso comercial.
Actinobacteria are Gram-positive organisms that have a high GC content in their genome. Bacteria in this phylum are capable of producing spores and antimicrobial agents. Also, these microorganisms can help degrade various polysaccharides such as chitin, lignocellulose, cellulose. Some Actinobacteria can live in symbiosis with termites, which can help decompose matter and may also protect the termites inhibiting the growth of entomopathogenic fungi. Previous studies have determined Actinobacteria inhibit the growth of entomopathogenic fungi such as Beauveria bassiana and Metarhizium anisopliae. The objective of this study is to determine secondary metabolites that can act as antimicrobial agents isolated from different Actinobacteria associated with a termite in Puerto Rico. Actinobacteria were isolated from Nasutitermes costalis termites collected in mangrove forests in Puerto Rico. Worker and soldier termites were macerated in phosphate buffer and the extract was inoculated in Chitin Agar plates. After isolating the bacteria, they were confronted with three different microorganisms (Escherichia coli, Staphylococcus aureus, and Beauveria bassiana). In addition, Actinobacteria isolates were used to perform a solid-liquid extraction of secondary metabolites using organic solvents (ethyl acetate and methanol). The ethyl acetate extracts were preliminarily subjected to chemical tests to identify functional groups. 1H- and 13C- Nuclear Magnetic Resonances (NMR) experiments indicated the presence of aldehydes, carboxylic acids, esters, and amides carbonyl groups, in addition to aromatic systems. Actinobacteria isolated from N. costalis had the capacity to inhibit the growth of confronted organisms in various degrees. The extract from Streptomyces isolate A4 presented growth inhibition of E. coli greater than a commercially used antibiotic.
Actinobacteria are Gram-positive organisms that have a high GC content in their genome. Bacteria in this phylum are capable of producing spores and antimicrobial agents. Also, these microorganisms can help degrade various polysaccharides such as chitin, lignocellulose, cellulose. Some Actinobacteria can live in symbiosis with termites, which can help decompose matter and may also protect the termites inhibiting the growth of entomopathogenic fungi. Previous studies have determined Actinobacteria inhibit the growth of entomopathogenic fungi such as Beauveria bassiana and Metarhizium anisopliae. The objective of this study is to determine secondary metabolites that can act as antimicrobial agents isolated from different Actinobacteria associated with a termite in Puerto Rico. Actinobacteria were isolated from Nasutitermes costalis termites collected in mangrove forests in Puerto Rico. Worker and soldier termites were macerated in phosphate buffer and the extract was inoculated in Chitin Agar plates. After isolating the bacteria, they were confronted with three different microorganisms (Escherichia coli, Staphylococcus aureus, and Beauveria bassiana). In addition, Actinobacteria isolates were used to perform a solid-liquid extraction of secondary metabolites using organic solvents (ethyl acetate and methanol). The ethyl acetate extracts were preliminarily subjected to chemical tests to identify functional groups. 1H- and 13C- Nuclear Magnetic Resonances (NMR) experiments indicated the presence of aldehydes, carboxylic acids, esters, and amides carbonyl groups, in addition to aromatic systems. Actinobacteria isolated from N. costalis had the capacity to inhibit the growth of confronted organisms in various degrees. The extract from Streptomyces isolate A4 presented growth inhibition of E. coli greater than a commercially used antibiotic.
Keywords
Actinobacteria,
Secondary metabolites,
Antimicrobial activity,
Streptomyces
Secondary metabolites,
Antimicrobial activity,
Streptomyces
Usage Rights
Persistent URL
Cite
Quiles Pérez, C. J. (2021). A new approach to fight microorganisms: Termite-associated actinobacteria secondary metabolites against pathogenic bacteria and fungi [Thesis]. Retrieved from https://hdl.handle.net/20.500.11801/2788