| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1490-1 | ||||
Resumo:Kyotorphin (KTP, l-tyrosyl-l-arginine) is an endogenous dipeptide, isolated in 1979 from bovine brain initially described to have analgesic properties. Previous studies show that some KTP derivatives possess anti-inflammatory and antimicrobial activity. Kyotorphin derivatives, KTP-NH2, KTP-NH2-DL, IbKTP, IbKTP-NH2, MetKTP-DL, MetKTP-LD, were designed and synthesized to improve lipophilicity and resistance to enzymatic degradation. In this work, the selected presented KTP derivatives were tested to improve their antimicrobial and antibiofilm activity. Peptides were synthesized by standard solution or solid-phase peptide synthesis and purified using RP-HPLC, which resulted in >95 % purity, and were fully characterized by 1H-NMR. The antimicrobial screening of the KTP derivatives were ascertained in the representative strains of bacteria including Streptococcus pneumoniae, Streptococcus pyogenes, Escherichia coli and Pseudomonas aeruginosa. The minimum inhibitory concentrations (MIC) calculated for bacterial strains were between 20 to 419 μM. The direct effect of IbKTP-NH2 on bacterial cells was imaged using scanning electron microscopy, showing that IbKTP-NH2 induces morphological changes in bacterial cells. The absence of toxicity and high survival after infection was evaluated by derivatives injections in Galleria mellonella larvae. Moreover, an increase in the hemocytes of G. mellonella infected with S. pneumoniae and P. aeruginosa and survival of species were observed after IbKTP-NH2 treatment. Proteomics analyses of G. mellonella hemolymph were performed to investigate the underlying mechanism of antibacterial activity of IbKTP-NH2 at MIC. Many differentially expressed proteins involved in DNA replication, synthesis of cell wall, and virulence were up-regulated after the treatment of G. mellonella with IbKTP-NH2. It was also possible to observe differences in expression of well-established proteins and peptides linked to the defense systems of G. mellonella, such as Cecropins Galiomicin, Gallerimycin, Gloverin, Hemolin and Phenoloxidase, after treatment. We suggest that this derivative, in addition to the physical activity on the membranes, can elicit a cellular and humoral immune response, therefore, it could be designed for biomedical application. Palavras-chave: kyotorphin, Galleria mellonella, proteome, antimicrobial, biofilm Agência de fomento:FAPESP | |||||