Naslov
A Legionella pneumophila amylase is essential for intracellular replication in human macrophages and amoebae

Autori
Ashley Best, Christopher Price, Mateja Ožanič, Marina Šantić, Snake Jones & Yousef Abu Kwaik

Izvornik
Scientific Reports (2045-2322) 8 (2018), 8; 1-14

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Legionella, amoebae, macrophages

Sažetak
Legionella pneumophila invades protozoa with an “accidental” ability to cause pneumonia upon transmission to humans. To support its nutrition during intracellular residence, L. pneumophila relies on host amino acids as the main source of carbon and energy to feed the TCA cycle. Despite the apparent lack of a requirement for glucose for L. pneumophila growth in vitro and intracellularly, the organism contains multiple amylases, which hydrolyze polysaccharides into glucose monomers. Here we describe one predicted putative amylase, LamB, which is uniquely present only in L. pneumophila and L. steigerwaltii among the ~60 species of Legionella. Our data show that LamB has a strong amylase activity, which is abolished upon substitutions of amino acids that are conserved in the catalytic pocket of amylases. Loss of LamB or expression of catalytically-inactive variants of LamB results in a severe growth defect of L. pneumophila in Acanthamoeba polyphaga and human monocytesderived macrophages. Importantly, the lamB null mutant is severely attenuated in intra-pulmonary proliferation in the mouse model and is defective in dissemination to the liver and spleen. Our data show an essential role for LamB in intracellular replication of L. pneumophila in amoeba and human macrophages and in virulence in vivo.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti, Kliničke medicinske znanosti

POVEZANOST RADA