Identificación e caracterización de microorganismos contaminantes de produtos lácteos, e busca de biomarcadores peptídicos mediante LC-ESI MS-MS

  1. Gónzalez Abril, Ana
Supervised by:
  1. Tomás González Villa Director
  2. María del Pilar Calo Mata Co-director

Defence university: Universidade de Santiago de Compostela

Fecha de defensa: 25 October 2019

Committee:
  1. Carmen Sieiro Vázquez Chair
  2. Carlos Rodríguez Osorio Secretary
  3. Maria Cristina Prudêncio Pereira Soares Committee member
Department:
  1. Department of Microbiology and Parasitology

Type: Thesis

Teseo: 602620 DIALNET lock_openMINERVA editor

Abstract

Ó capítulo I deste traballo centrase na identificación das cepas illadas dun sobre contaminado de leite condensada e a caracterización dunha nova subespecie de Bacillus safensis (BC09T). Realizouse o estudo filoxenético de BC09T a partir dos xenes do 16S rRNA, gyrB e tuf. Levouse a cabo a secuenciación do xenoma e o seu análise. Realizouse tamén o estudo fenotípico, quimiotaxonómico e proteómico mediante MALDI TOF. Segundo tódolos resultados determinouse que a cepa BC09T representa unha nova subespecie de B. safensis, co nome de Bacillus safensis subsp. osmophilus subsp. nov. No capitulo II de esta tese, levouse a cabo o estudo dos péptidos trípticos analizados por LC-ESI-MS/MS de Streptococcus spp. e S. aureus illadas de leite e produtoras de mastite. Co obxectivo de determinar péptidos biomarcadores para estas cepas, estudáronse os péptidos específicos de orixe fáxico e pertencentes a factores de virulencia. Seleccionáronse varios péptidos específicos de especie como potenciais biomarcadores. Chapter I of this research focuses on identification of strains isolated from a contaminated sample of condensed milk and the characterization of a new subspecies of Bacillus safensis (BC09T). Phylogenetic analyses based on 16S rRNA, gyrB and tuf genes of BC09T have been performed. Genome sequencing and its analysis has been conducted. Moreover, phenotypic chemotaxonomic and proteomic studies by MALDI TOF have been performed. Results showed that strain BC09T represents a new subspecies of B. safensis, for which the name Bacillus safensis subsp. osmophilus subsp. nov. is proposed. Chapter II of this thesis focuses on the analysis of tryptic digestion peptides from mastitis producer Streptococcus spp. and S. aureus isolated from milk, by LC-ESI-MS/MS. In order to search for specific biomarkers of such analysed strains, phage origin and virulence factors peptides were studied. Determined specie specific peptides are thought to be useful as biomarkers.