RESUMO
Chromobacterium is a rod-shaped, Gram-negative, facultatively anaerobic bacteria with a cosmopolitan distribution. Just about 160 Chromobacterium violaceum incidents have been reported globally, but then once infected, it has the ability to cause deadly septicemia, and infections in the lungs, liver, brain, spleen, and lymphatic systems that might lead to death. C. violaceum produces and utilizes violacein to kill bacteria that compete with it in an ecological niche. Violacein is a hydrophobic bisindole that is delivered through an efficient transport route termed outer membrane vesicles (OMVs) through the aqueous environment. OMVs are small, spherical segments detached from the outer membrane of Gram-negative bacteria. C. violaceum OMV secretions are controlled by a mechanism called the quorum sensing system CviI/CviR, which enables cell-to-cell communication between them and regulation of various virulence factors such as biofilm formation, and violacein biosynthesis. Another virulence factor bacterial type 3 secretion system (T3SS) is divided into two types: Cpi-1 and Cpi-2. Cpi-1's needle and rod effector proteins are perhaps recognized by NAIP receptors in humans and mice, activating the NLRC4 inflammasome cascade, effectively clearing spleen infections via pyroptosis, and cytotoxicity mediated by IL-18-driven Natural killer (NK) cells in the liver. In this paper, we attempt to interrelate quorum-controlled biofilm formation, violacein production, violacein delivery by OMVs and T3SS effector protein production and host mediated immunological effects against the Cpi1 of T3SS. We suggest a research path with natural bioactive molecule like palmitic acid that can act as an anti-quorum agent by reducing the expression of virulence factors as well as an immunomodulatory agent that can augment innate immune defense by hyperactivation of NLRC4 inflammasome hence dramatically purge C. violaceum infections.
RESUMO
Proline-rich protein (PRP), a cell wall protein of plant, has been studied in many plant species. Yet, none of the PRPs has been functionally elucidated. Here we report a novel flower-specific PRP designated OsPRP3 from rice. Expression analysis showed that the OsPRP3 transcript was mainly present in rice flower and accumulated abundantly during the late stage of the flower development. To study the function of OsPRP3, we constructed and transformed a binary vector containing a full clone of OsPRP3 in sense orientation and also an RNAi vector to achieve overexpression and knockout of the gene, respectively. Our overexpression plants showed a significant increase in cold tolerance than the WT plants which is conferred by the accumulation of OsPRP3 protein during cold treatment. Further the microscopic analysis revealed that OsPRP3 enhances the cell wall integrity in the cold tolerant plant and confers cold-tolerance in rice. Microscopic analysis of the RNAi mutant flower revealed that blocking OsPRP3 function caused significant defects in floral organogenesis. Taken together, the results suggested that OsPRP3 is a cell wall protein, playing a crucial role in determining extracellular matrix structure of floral organs.