Resultados de investigación

Mycoplasma cells were in the presence of SP4 medium supplemented with 3% gelatin. Frames were taken each 0.5 seconds of observation and are showed at 20 frames per second in the movie. The blank frame/s in the first seconds of the movie denote when the polyclonal antisera was added to the cells., Peer reviewed

Mycoplasma cells were in the presence of SP4 medium supplemented with 3% gelatin. Frames were taken each 0.5 seconds of observation and are showed at 20 frames per second in the movie. The blank frame/s in the first seconds of the movie denote when the polyclonal antisera was added to the cells., Peer reviewed

The clock counter timer at the top-left side of the movie shows the actual microcinematography time in mm:ss format (m: minutes; s: seconds). P1/MCA4 at a final concentration of 10 μg mL−1 was added to the culture medium at minute 1:10. This microcinematography was performed with no gelatin added to the culture medium., Peer reviewed

Mycoplasma pneumoniae and Mycoplasma genitalium are bacterial wall-less human pathogens and the causative agents of respiratory and reproductive tract infections. Infectivity, gliding motility and adhesion of these mycoplasmas to host cells are mediated by orthologous adhesin proteins forming a transmembrane adhesion complex that binds to sialylated oligosaccharides human cell ligands. Here we report the cryo-EM structure of M. pneumoniae P1 adhesin bound to the Fab fragment of monoclonal antibody P1/MCA4, which stops gliding and induces detachment of motile cells. The epitope of P1/MCA4 involves residues only from the small C-domain of P1. This epitope is accessible to antibodies only in the “closed conformation” of the adhesion complex and is not accessible in the “open” conformation, when the adhesion complex is ready for attachment to sialylated oligosaccharides. Polyclonal antibodies generated against the large N-domain of P1 or against the whole ectodomain of P40/P90 have little or no effects on adhesion or motility. Moreover, mutations in the highly conserved Engelman motifs found in the transmembrane helix of M. genitalium P110 adhesin also alter adhesion and motility. These results show that antibodies directed to the C-domain of P1 hinder the large conformational rearrangements in this domain required to alternate between the “open” and “closed” conformations of the adhesion complex. Since transition between both conformations is essential to complete the attachment/detachment cycle of the adhesion complex, interfering with the gliding of mycoplasma cells and providing a new potential target to confront M. pneumoniae and M. genitalium infections., Peer reviewed

Primers used in the generation of M. genitalium adhesins constructs., Peer reviewed

Plasmids used for expression of P1 protein fragments for epitope mapping of P1/MCA4., Peer reviewed

Primers used for P1 and P40/P90 protein constructs expression., Peer reviewed

Quantification of the frequency of cells with multiple terminal organelles (mTO) and cells with no terminal organelle for each strain., Peer reviewed

Mycoplasma pneumoniae and Mycoplasma genitalium are bacterial wall-less human pathogens and the causative agents of respiratory and reproductive tract infections. Infectivity, gliding motility and adhesion of these mycoplasmas to host cells are mediated by orthologous adhesin proteins forming a transmembrane adhesion complex that binds to sialylated oligosaccharides human cell ligands. Here we report the cryo-EM structure of M. pneumoniae P1 adhesin bound to the Fab fragment of monoclonal antibody P1/MCA4, which stops gliding and induces detachment of motile cells. The epitope of P1/MCA4 involves residues only from the small C-domain of P1. This epitope is accessible to antibodies only in the “closed conformation” of the adhesion complex and is not accessible in the “open” conformation, when the adhesion complex is ready for attachment to sialylated oligosaccharides. Polyclonal antibodies generated against the large N-domain of P1 or against the whole ectodomain of P40/P90 have little or no effects on adhesion or motility. Moreover, mutations in the highly conserved Engelman motifs found in the transmembrane helix of M. genitalium P110 adhesin also alter adhesion and motility. These results show that antibodies directed to the C-domain of P1 hinder the large conformational rearrangements in this domain required to alternate between the “open” and “closed” conformations of the adhesion complex. Since transition between both conformations is essential to complete the attachment/detachment cycle of the adhesion complex, interfering with the gliding of mycoplasma cells and providing a new potential target to confront M. pneumoniae and M. genitalium infections., Peer reviewed

Culex pipiens females collected as larvae and reared at the laboratory were allowed to feed either on an naturally Plasmodium relictum-infected house sparrow (Passer domesticus) or an uninfected house sparrow. Genomic DNA was extracted from the abdomen of the mosquitoes and the 16S rRNA gene was sequenced., This work was supported by the MICIU/AEI/10.13039/501100011033 under grant PID2020-118205GB-I00 and PID2021-123761OB-I00, Peer reviewed