title: Antimicrobial Activity of ILTI, a Kunitz-Type Trypsin Inhibitor from Inga laurina (SW.) Willd.
abstract: Over the last few years, a growing number of proteinase inhibitors have been isolated from plants and particularly from seeds and have shown antimicrobial activity. A 20,000 Da serine peptidase inhibitor, named ILTI, was isolated from Inga laurina seeds and showed potent inhibitory enzymatic activity against trypsin. The aim of this study was to determine the effects of ILTI on the growth of pathogenic and non-pathogenic microorganisms. We observed that ILTI strongly inhibited in particular the growth of Candida tropicalis and Candida buinensis, inducing cellular agglomeration. However, it was ineffective against human pathogenic bacteria. We also investigated the potential of ILTI to permeabilize the plasma membrane of yeast cells. C. tropicalis and C. buinensis were incubated for 24 h with the ILTI at different concentrations, which showed that this inhibitor induced changes in the membranes of yeast cells, leading to their permeabilization. Interestingly, ILTI induced the production of reactive oxygen species (ROS) in C. tropicalis and C. buinensis cells. Finally, ILTI was coupled with fluorescein isothiocyanate, and subsequent treatment of C. tropicalis and C. buinensis with DAPI revealed the presence of the labeled protein in the intracellular spaces. In conclusion, our results indicated the ability of peptidase inhibitors to induce microbial inhibition; therefore, they might offer templates for the design of new antifungal agents.
authors.affiliation: Laboratório de Purificação de Proteínas e suas Funções Biológicas, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, Cidade Universitária S/N, Caixa Postal 549, Campo Grande, MS, 79070-900, Brazil. bioplant@terra.com.br.
authors.forename: Maria Lígia R
authors.initials: ML
authors.lastname: Macedo
authors.affiliation: Laboratório de Fisiologia e Bioquímica de Microrganismos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, 28013-602, Brazil.
authors.forename: Suzanna F F
authors.initials: SF
authors.lastname: Ribeiro
authors.affiliation: Laboratório de Fisiologia e Bioquímica de Microrganismos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, 28013-602, Brazil.
authors.forename: Gabriel B
authors.initials: GB
authors.lastname: Taveira
authors.affiliation: Laboratório de Fisiologia e Bioquímica de Microrganismos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, 28013-602, Brazil.
authors.forename: Valdirene M
authors.initials: VM
authors.lastname: Gomes
authors.affiliation: Laboratório de Purificação de Proteínas e suas Funções Biológicas, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, Cidade Universitária S/N, Caixa Postal 549, Campo Grande, MS, 79070-900, Brazil.
authors.forename: Karina M C A
authors.initials: KM
authors.lastname: de Barros
authors.affiliation: Laboratório de Purificação de Proteínas e suas Funções Biológicas, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, Cidade Universitária S/N, Caixa Postal 549, Campo Grande, MS, 79070-900, Brazil.
authors.forename: Simone
authors.initials: S
authors.lastname: Maria-Neto
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects / Q000378:metabolism; D002177:Candidiasis / Q000382:microbiology; D007887:Fabaceae / Q000737:chemistry*; D006801:Humans; D008826:Microbial Sensitivity Tests; D018384:Oxidative Stress / Q000187:drug effects; D010940:Plant Proteins / Q000494:pharmacology*; D012639:Seeds / Q000737:chemistry; D014361:Trypsin Inhibitors / Q000494:pharmacology*
chemical_list: D000935:Antifungal Agents; D010940:Plant Proteins; D014361:Trypsin Inhibitors