PubMed · 6662392
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
R Tamir, A I Pick. 1983-03-01. [The complement and its interaction with leukocytes].. https://pubmed.ncbi.nlm.nih.gov/6662392/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The dissemination of antibiotic resistance genes (ARGs) in wastewater environments poses a severe threat to public health. Extracellular ARGs (eARGs) persist as free DNA fragments that are refractory to efficient removal by conventional physicochemical treatment technologies. Here, we isolated Stutzerimonas stutzeri CHY07 from municipal sewage and demonstrated that extracellular DNA fragments, including eARGs, can serve as chemoattractants for environmental bacteria. Through genomic mining, molecular docking, surface plasmon resonance (SPR), isothermal titration calorimetry (ITC) and protein-ligand interaction profiling, we identified the chemoreceptor Mcp16 as the primary sensor of extracellular DNA and revealed that it achieves sequence-independent recognition of the DNA phosphate backbone. We further established the endogenous pentapeptide VRSVR as a methylation substrate for CheR and constructed the engineered strain CHY07-2 (mcp16::VRSVR) using an SSB/CRISPR-Cas9 ribonucleoprotein (RNP) system. This strain exhibited significantly enhanced chemotactic responsiveness, achieving 72-h removal efficiencies of 96.56% and 91.60% for low- and high-molecular-weight eARGs in non-sterile WWTP secondary effluent; conversely, mcp16 deletion markedly attenuated both chemotaxis and removal, whereas in situ complementation restored them. These findings reveal a "chemotaxis-contact-removal" cascade - with a proposed self-reinforcing loop - in eARG-removing bacteria, providing both a theoretical framework and a technical paradigm for enhancing pollutant removal through targeted amplification of microbial chemotaxis.
Two interleukin-8 (IL-8) receptors, alpha and beta, have been identified and cloned. Both receptors are thought to transduce signals by coupling to GTP-binding proteins. The aim of this study is to determine whether the carboxyl terminus (C') of IL-8 receptor beta (IL-8R beta) is involved in signaling in response to IL-8. We have constructed a number of IL-8R beta genes that encode truncated forms of the IL-8R beta. The deletions consisted of amino acids 349-355, 336-355, 325-355, and 317-355 (termed beta 2, beta 3, beta 4, and beta 5, respectively). 293 human embryonic kidney cells were transfected with the wild type IL-8R beta (beta 1) and with these mutants. Cells transfected with the mutated receptors expressed the receptors and bound IL-8 with the same high affinity as cells transfected with the wild type receptor. The capacity of the mutated receptors to convey functional signals was evaluated by comparing the chemotaxis index of cells expressing the C'-truncated receptors to the index of cells expressing the wild type receptor. The results indicate that while cells expressing beta 1, beta 2, beta 3, and beta 4 were chemoattracted in response to IL-8, cells expressing beta 5 did not migrate in response to IL-8 stimulation. Therefore, the data suggest that amino acids 317-324 are involved in signaling by IL-8R beta.
Explore the source record for details and available documents.