No abstract

Models of host–pathogen interactions are crucial for the analysis of microbial pathogenesis. In this context, invertebrate hosts, including Drosophila melanogaster (fruit fly), Caenorhabditis elegans (nematode) and Galleria mellonella (moth), have been used to study the pathogenesis of fungi and bacteria. Each of these organisms offers distinct benefits in elucidating host–pathogen interactions. In this study,we present a newinvertebrate infection model to study fungal infections: the Tenebrio molitor (beetle) larvae. Here we performed T. molitor larvae infection with one of two important fungal human pathogens, Candida albicans or Cryptococcus neoformans, and analyzed survival curves and larva infected tissues.We showed that increasing concentrations of inoculum of both fungi resulted in increased mortality rates, demonstrating the efficiency of the method to evaluate the virulence of pathogenic yeasts. Additionally, following 12 h post-infection, C. albicans formsmycelia, spreading its hyphae through the larva tissue,whilst GMS stain enabled the visualization of C. neoformans yeast and theirmelanin capsule. These larvae are easier to cultivate in the laboratory than G. mellonella larvae, and offer the same benefits. Therefore, this insect model could be a useful alternative tool to screen clinical pathogenic yeast strainswith distinct virulence traits or different mutant strains.

Faced with ethical conflict and social pressure, researchers have increasingly chosen to use alternative models over vertebrates in their research. Since the innate immune system is evolutionarily conserved in insects, the use of these animals in research is gaining ground. This review discusses Tenebrio molitor as a potential model host for the study of pathogenic fungi. Larvae of T. molitor are known as cereal pests and, in addition, are widely used as animal and human feed. A number of studies on mechanisms of the humoral system, especially in the synthesis of antimicrobial peptides, which have similar characteristics to vertebrates, have been performed. These studies demonstrate the potential of T. molitor larvae as a model host that can be used to study fungal virulence, mycotoxin effects, host immune responses to fungal infection, and the action of antifungal compounds.

No abstract

No abstract

INTRODUÇÃO:O ferro é essencial para a funcionalidade dos processos biológicos, porém o excesso de ferro é tóxico. Em humanos, devido à sua toxicidade, esse metal é encontrado acoplado a proteínas, como a transferrina, que transporta o ferro para os tecidos, e a ferritina, molécula de armazenamento intracelular desse metal. Durante uma infecção, os microrganismos obtêm ferro do hospedeiro para sobreviver. Candida albicans, um dos principais patógenos responsáveis por doenças fúngicas graves, contém uma proteína transmembrana, a permeasse de ferro de alta afinidade, Ftr1, que usa para obter ferro da ferritina, transferrina e de quelantes de ferro sintetizados por outros microrganismos. Na busca de novos mecanismos para conter a multiplicação fúngica, os anticorpos são aplicáveis, pois é possível produzir anticorpos específicos contra uma estrutura microbiana. OBJETIVOS: Neste contexto, o objetivo do trabalho foi avaliar a atividade antifúngica in vivo de anticorpos de galinha (IgY) produzidos contra a permease de ferro Ftr1 de C. albicans. METODOLOGIA: Um peptídeo derivado da Ftr1 foi sintetizado e utilizado para imunizar galinhas poedeiras. Os anticorpos IgY foram extraídos de gemas dos ovos, purificados e caracterizados. Para determinar o efeito antifúngico das imunoglobulinas, foi realizado testes in vivo em larvas da mariposa Galleria mellonella, um modelo alternativo de infecção sistêmica. As larvas foram inoculadas, por injeção, com 1 x 10 5

Aims: The aim of this study was to evaluate the protective capacity of the exopolysaccharide-producing Lactobacillus rhamnosus V5 against invasion in vitro and in vivo with S. typhimurium. Methodology: We tested the antimicrobial activity of the compound extracted from the            lactobacilli against S. typhimurium directly, also we tested the interference of this compound in S. typhimurium adherence and invasion of HeLa and HEp-2 cells (in vitro testings). For in vivo experiments, we used 16 BALB/c female mice. Through gavage method we introduced L. rhamnosus as probiotic and then infected mice with S. enterica serovar typhimurium. After euthanasia, spleen, liver and Peyer's patches removed for microbiological and histopathological analysis. Results: The results showed that lactobacilli were able to produce antimicrobial compounds  against S. typhimurium. These lactobacilli inhibited the adhesion and invasion of S. typhimurium  in HeLa and HEp-2 cells, respectively. The challenge assay in the murine model demonstrated a decrease in pathogen translocation in the spleen and liver from mice treated with probiotic as  well as protection of ileal tissue in lactobacilli-treated mice. The histopathological analysis demonstrated the presence of prominent lymphoid nodules in the ileum from the non-treated lactobacilli mice. Conclusion: Our results suggest that L. rhamnosus improved the effectiveness of the intestinal barrier and, thus, could be a potential probiotic to control salmonellosis.

No abstract