the same limited diversity as gram-positive porins, and also display a greater voltage-dependent role during metabolism. Archaea also contain ion channels that have originated from general porins. The channels are found in the cell envelope and help facilitate solute transfer. They have similar characteristics as bacterial and mitochondrial porins, indicating physiological overlaps over all three domains of life. Antibiotic resistance Many porins are targets for host immune cells, resulting in signaling pathways that lead to bacterial degradation. Therapeutic treatments, like vaccinations and antibiotics, are used to supplement this immune response. Specific antibiotics have been designed to travel through porins in order to inhibit cellular processes. However, due to selective pressure, bacteria can develop resistance through mutations in the porin gene. The mutations may lead to a loss of porins, resulting in the antibiotics having a lower permeability or being completely excluded from transport. These changes have contributed to the global emergence of antibiotic resistance, and an increase in mortality rates from infections. Discovery The discovery of porins has been attributed to Hiroshi Nikaido, nicknamed "the porinologist." Classification According to TCDB, there are five evolutionarily independent superfamilies of porins. Porin superfamily I includes 47 families of porins with a range of numbers of trans-membrane β-strands (β-TMS). These include the GBP, SP and RPP porin families. While PSF I includes 47 families, PSF II-V each contain only 2 families. While PSF I derives members from gram-negative bacteria primarily one family of eukaryotic mitochondrial porins, PSF II and V porins are derived from Actinomycetota. PSF III and V are derived from eukaryotic organelle. Porin Superfamily I 1.B.1 - The General bacterial porin family 1.B.2 - The Chlamydial Porin (CP) Family 1.B.3 - The Sugar porin (SP) Family 1.B.4 - The Brucella-Rhizobium porin (BRP) Family 1.B.5 - The Pseudomonas OprP Porin (POP) Family 1.B.6 - OmpA-OmpF porin (OOP) family 1.B.7 Rhodobacter PorCa porin (RPP) family 1.B.8 Mitochondrial and plastid porin (MPP) family 1.B.9 FadL outer membrane protein (FadL) family 1.B.10 Nucleoside-specific channel-forming outer membrane porin (Tsx) family 1.B.11 Outer membrane fimbrial usher porin (FUP) family 1.B.12 Autotransporter-1 (AT-1) family 1.B.13 Alginate export porin (AEP) family 1.B.14 Outer membrane receptor (OMR) family 1.B.15 Raffinose porin (RafY) family 1.B.16 Short chain amide and urea porin (SAP) family 1.B.17 Outer membrane factor (OMF) family 1.B.18 Outer membrane auxiliary (OMA) protein family 1.B.19 Glucose-selective OprB porin (OprB) family 1.B.20 Two-partner secretion (TPS) family 1.B.21 OmpG porin (OmpG) family