Induction of iron regulated proteins during normal growth of Neisseria meningitidis in a chemically defined medium Indução das proteínas reguladas pelo ferro durante o crescimento normal de Neisseria meningitidis em meio quimicamente definido

• Published in: Revista do Instituto de Medicina Tropical de São Paulo
• Main Authors: Maria Cristina de Cunto Brandileone, Rosemeire Cobo Zanella, Vera Simonsen Dias Vieira, Claudio Tavares Sacciii, Lucimar Gonçalves Milagres, Carl Eduard Frasch
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universidade de São Paulo (USP) 1994
• Subjects: Neisseria meningitidis; Iron regulated proteins; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic; Ferro; Mueller
• Online Access: https://doi.org/10.1590/S0036-46651994000400002; https://doaj.org/article/bc2eb38a31bc4e238213a25c630169d4

The expression of iron regulated proteins (IRPs) in vitro has been obtained in the past by adding iron chelators to the culture after bacterial growth, in the presence of an organic iron source. We have investigated aspects concerning full expression of the meningococcal IRPs during normal growth, in defined conditions using Catlin medium, Mueller Hinton and Tryptic Soy Broth (TSB). The expression of IRPs varied between different strains with respect to Ethylenediamine Di-ortho-Hidroxy-phenyl-acetic acid (EDDA) concentrations, and according to culture medium, and also between different lots of TSB. For each strain, a specific set of IRPs were expressed and higher EDDA concentrations, or addition of glucose, or use of different culture media did not resulted in a differential expression of IRPs. We were not able to grow N. meningitidis under normal growth conditions using Desferal. We looked for a good yield of outer membrane vesicles (OMVs) expressing IRPs in iron-deficient Catlin medium containing EDDA and Hemin. Culture for 32 h at 30ºC after growing for 16 h at 37ºC supported good bacterial growth. Bacterial lysis was noted after additional 24 h at 30ºC. Approximately 4 times more OMVs was recoverable from a culture supernatant after 24 h at 30ºC than from the cells after 16 h at 37ºC. The IRP were as well expressed in OMVs from culture supernatant obtained after 24 h at 30ºC as from the cells after 16 h at 37ºC. A expressão das proteínas reguladas pelo ferro (IRPs), in vitro, tem sido obtida pela adição de quelantes de ferro ao meio de cultura, após o crescimento bacteriano, na presença de fonte de ferro orgânico. Neste estudo foram investigados aspectos da máxima expressão das IRPs de meningococo durante o crescimento normal, em condições de cultura definidas, utilizando-se o meio de Catlin e os caldos Mueller-Hinton e Tryptic Soja (TSB). Foram avaliadas as melhores condições para se obter vesículas de membrana externa (OMVs) contendo IRPs para uso em vacina de meningococo B. A expressão das IRPs variou ...