RESUMO
Neutrophil extracellular trap (NET) formation plays an important role in inflammatory diseases. Although it is known that NET formation occurs via NADPH oxidase (NOX)-dependent and NOX-independent pathways, the detailed mechanism remains unknown. Therefore, in this study, we aimed to elucidate the role of mitochondria in NOX-dependent and NOX-independent NET formation. We generated mitochondrial DNA-deficient cells (ρ0 cells) by treating HL-60 cells with dideoxycytidine and differentiated them to neutrophil-like cells. These neutrophil-like ρ0 cells showed markedly reduced NOX-independent NET formation but not NOX-dependent NET formation. However, NET-associated intracellular histone citrullination was not inhibited in ρ0 cells. Furthermore, cells membrane disruption in NOX-dependent NET formation occurred in a Myeloperoxidase (MPO) and mixed lineage kinase domain like pseudokinase (MLKL)-dependent manner; however, cell membrane disruption in NOX-independent NET formation partially occurred in an MLKL-dependent manner. These results highlight the importance of mitochondria in NOX-independent NET formation.
RESUMO
The genome organization, gene structure, and host range of five podoviruses that infect Ralstonia solanacearum, the causative agent of bacterial wilt disease were characterized. The phages fell into two distinctive groups based on the genome position of the RNA polymerase gene (i.e., T7-type and ÏKMV-type). One-step growth experiments revealed that ÏRSB2 (a T7-like phage) lysed host cells more efficiently with a shorter infection cycle (ca. 60 min corresponding to half the doubling time of the host) than ÏKMV-like phages such as ÏRSB1 (with an infection cycle of ca. 180 min). Co-infection experiments with ÏRSB1 and ÏRSB2 showed that ÏRSB2 always predominated in the phage progeny independent of host strains. Most phages had wide host-ranges and the phage particles usually did not attach to the resistant strains; when occasionally some did, the phage genome was injected into the resistant strain's cytoplasm, as revealed by fluorescence microscopy with SYBR Gold-labeled phage particles.
Assuntos
RNA Polimerases Dirigidas por DNA/genética , Variação Genética , Genoma Viral , Podoviridae/genética , Ralstonia solanacearum/virologia , Proteínas Virais/genética , Bacteriófagos , Mapeamento Cromossômico , Coinfecção , Genótipo , Especificidade de Hospedeiro , Lisogenia/genética , Tipagem Molecular , Doenças das Plantas/microbiologia , Podoviridae/classificação , Podoviridae/patogenicidadeRESUMO
PhiRSB1 is a wide-host-range, T7-like bacteriophage that infects and efficiently lyses the phytopathogenic bacterium Ralstonia solanacearum. The phiRSB1 genome comprises 43,079 bp of double-stranded DNA (61.7% G+C) with 325-bp terminal repeats and contains 47 open reading frames. Strong activity of tandem early promoters and wide specificity of phage promoters of phiRSB1 were demonstrated.