African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5232

Full Length Research Paper

Characterisation of a Bifidobacterium sp. strain isolated from human faeces and its expression of the ack and ldh genes

Olvera Rangel N., Gutiérrez Nava A.*, Azaola Espinosa A. and Mayorga Reyes L.
Departamento de Sistemas Biológicos, Universidad Autónoma Metropolitana, UnidadXochimilco. D.F. C.P. 04960, México.
Email: [email protected]

  •  Accepted: 20 November 2013
  •  Published: 31 December 2013

Abstract

Faecal samples of two Mexican breast-fed infants were used to isolate a Bifidobacterium strain in a selective medium. This strain was characterised biochemically for carbohydrate fermentation patterns and the fructose-6-phosphate phosphoketolase assay; genetically it was identified by PCR using genus-specific primers. The isolated strain was named Bifidobacterium JCLA3 and was grown on four different carbon sources; the respective growth kinetics of glucose, lactose, inulin and sucrose were measured. The highest cellular yield was presented in the culture media containing sucrose, followed by inulin, while on glucose and lactose, the cellular yield was lowest; these results correlate with the characteristic that bifidobacteria prefer complex carbon sources. We also determined the expression of the ack and ldh genes. The ldh gene presented high levels of expression regarding the ack gene; nevertheless on sucrose, the expression was lower regarding the other three substrates. The highest expression level of the ack gene was from the culture media with glucose, followed by inulin, sucrose and lactose. 

 

Key words: Bifidobacterium, characterisation, gene expression.