Tesis profesional presentada por
Licenciatura en Biología. Departamento de Ciencias Químico Biológicas. Escuela de Ciencias, Universidad de las Américas Puebla.
Presidente: Dr. José Daniel Lozada
Vocal y Director: Dr. José Luis Sánchez Salas
Secretario: Mtro. Jerónimo García Guzmán
Cholula, Puebla, México a 15 de mayo de 2010.
It is important to understand how B. subtilis grows in harsh conditions to demonstrate the probability of microbial growth in low O2 conditions, even in anoxia and low atmospheric pressure. In this study we used three strains of B.subtilis where two expressed the gene vgb of Vitreoscilla stercoraria using plasmids pUB110::sspE::vgb (multicopy), pTrp::vgb (with one integrative copy) which affects the growth of B . subtilis and a third one wild-type. Strains were inoculated in nephelometric flasks with 2xYT medium. Bacterial growth of the three strains of B.subtilis was measured by the absorbance values obtained from a SPECTRONIC 20D + spectrophotometer (Milton Roy) at 37 ° C in five conditions: aerobic, microaerophilic, vacuum, anaerobiosis and anaerobiosis + vacuum. The strains grew in all different conditions however, the best growth was observed from the aerobic and microaerophilic conditions. The strain with plasmid pUB110:: sspE::vgb (multicopy) increased in greater proportion in the vacuum conditions and in anaerobiosis. The wild type strain with the plasmid pUB110:: sspE::vgb had a better growth with less lag phase in the absence of oxygen. However, the strain with the plasmid pTrp: vgb grew poorly, probably due to fact that when this plasmid becomes integrated in the bacterial chromosome, disrupts the gene for starch utilization, affecting in some way growth and development. Growth rate (k), generation time (g) and statistics analysis where corroborated in the logarithmic phase of each bacterial growth curve. We conclude that since B.subtilis can growth under extreme environmental situations, including anoxic conditions, could offer the possibility to be used as a starter to colonize neighbor planets in our solar system with low atmospheric pressures provided that necessary nutrients are provided. Additionally, recent evidence of water in Mars suggests that this could be a possibility in the next decades.
Sánchez Quinto, A. 2010. Influencia del crecimiento de Bacillus subtilis conteniendo varias copias del gen vgb de Vitreoscilla stercoraria en diferentes concentraciones de oxígeno y a diferentes presiones. Tesis Licenciatura. Biología. Departamento de Ciencias Químico Biológicas, Escuela de Ciencias, Universidad de las Américas Puebla. Mayo. Derechos Reservados © 2010.