sdpC Antibody

The sdpC antibody targets a 42-residue extracellular sporulation delaying protein (SDP) that disrupts the proton motive force (impacting both the membrane potential and pH gradient) across the cell membrane. This disruption leads to autolysis, potentially through the formation of a proton channel. SDP induces lysis in other Bacillus subtilis cells that have not yet entered the sporulation pathway, causing cannibalism. This provides a source of nutrients for sporulation while simultaneously delaying the commitment to sporulation, an energy-intensive and irreversible process. When added to liquid cultures, SDP inhibits growth, increases cell permeability, and ultimately leads to lysis in a substantial portion of the population. However, some cells survive and resume growth after a lag period. The effects of SDP are irreversible within 10 minutes. When applied to solid cultures, SDP induces killing, demonstrating greater efficacy than SKF (AC O31422). SDP exhibits antibiotic activity against Gram-positive Firmicutes (e.g., Lactobacillus acidophilus, Micrococcus megaterium, Paenibacillus polymyxa, Staphylococcus aureus, Staphylococcus epidermidis) but not against Actinobacteria (e.g., Micrococcus luteus) or Gram-negative bacteria (e.g., Pseudomonas aeruginosa, Klebsiella pneumoniae). SDP triggers the expression of the sdpR-sdpI operon. Its maturation depends on SdpA and SdpB. SDP also functions as a ligand, binding to SdpI and initiating a signal transduction cascade that protects the cell from the toxic effects of its own SDP.