Application of high-resolution melting-curve analysis on pvpA gene for detection and classification of Mycoplasma gallisepticum strains

Mycoplasma gallisepticum escapes the host immune response via gga-miR-365-3p/SOCS5/STATs axis

A disruption in the expression of gga-miR-365-3p was confirmed in the Mycoplasma gallisepticum (MG)-infected Chicken primary alveolar type II epithelial (CP-II) cells based on previous sequencing results, but the role it plays in the infection was unclear. In the present study, we demonstrate that MG evaded cellular host immunity via a gga-miR-365-3p/SOCS5-JAK/STATs negative feedback loop. Specifically, we found that at the initial stage of MG infection in cells, gga-miR-365-3p was rapidly increased and activated the JAK/STAT signaling pathway by inhibiting SOCS5, which induced the secretion of inflammatory factors and triggered immune response against MG infection. Over time, though, the infection progressed, MG gradually destroyed the immune defences of CP-II cells. In late stages of infection, MG escaped host immunity by reducing intracellular gga-miR-365-3p and inhibiting the JAK/STAT pathway to suppress the secretion of inflammatory factors and promote MG adhesion or invasion. These results revealed the game between MG and host cell interactions, providing a new perspective to gain insight into the pathogenic mechanisms of MG or other pathogens. Meanwhile, they also contributed to novel thoughts on the prevention and control of MG and other pathogenic infections, shedding light on the immune modulating response triggered by pathogen invasion and their molecular targeting.

High-resolution melting curve analysis: a novel method for identification of Mycoplasma species isolated from clinical cases of bovine and porcine respiratory disease

Mycoplasma species cause wide ranges of infectious diseases in human and animals. The aim of the present study was to evaluate a real-time polymerase chain reaction (RT-PCR) followed by a high-resolution melting curve assay (HRM) for rapid differentiation of Mycoplasma species isolated from clinical cases of bovine and porcine respiratory disease. Lung samples from suspected cases to respiratory infections from cows and pigs were cultured on specific media, and the extracted DNA were tested by conventional polymerase chain reaction (PCR) assays for Mycoplasma. A set of universal primers specific for the 16S ribosomal RNA gene was designed and used for RT-PCR and HRM. The HRM analysis was able to differentiate between five different species of Mycoplasmas, namely, M. hyopneumoniae, M. bovis, M. hyorhinis, M. hyosynoviae and other uncultured Mycoplasma. All results were confirmed based on 16S rRNA gene sequencing. This rapid and reliable assay was as a simple alternative to PCR and sequencing, differentiating bovine and porcine mycoplasmas in species level.