Proteomic Analysis of the Responses of Candida albicans during Infection of Galleria mellonella Larvae

Abstract

This study assessed the development of disseminated candidiasis within Galleria mellonella larvae and characterized the proteomic responses of Candida albicans to larval hemolymph. Infection of larvae with an inoculum of 1 × 106 yeast cells reduced larval viability 24 (53.33 ± 3.33%), 48 (33.33 ± 3.33%) and 72 (6.66 ± 3.33%) h post infection. C. albicans infection quickly disseminated from the site of inoculation and the presence of yeast and hyphal forms were found in nodules extracted from infected larvae at 6 and 24 h. A range of proteins secreted during infection of G. mellonella by C. albicans were detected in larval hemolymph and these were enriched for biological processes such as interaction with host and pathogenesis. The candicidal activity of hemolymph after immediate incubation of yeast cells resulted in a decrease in yeast cell viability (0.23 ± 0.03 × 106 yeast cells/mL), p < 0.05) as compared to control (0.99 ± 0.01 × 106 yeast cells/mL). C. albicans responded to incubation in hemolymph ex vivo by the induction of an oxidative stress response, a decrease in proteins associated with protein synthesis and an increase in glycolytic proteins. The results presented here indicate that C. albicans can overcome the fungicidal activity of hemolymph by altering protein synthesis and cellular respiration, and commence invasion and dissemination throughout the host.

Candida albicans increases the pathogenicity of Staphylococcus aureus during polymicrobial infection of Galleria mellonella larvae

“…Previous work has visualized the dissemination of C. albicans and S. aureus , separately, in larvae [39]. In this case cryo-imaging was employed to assess the development of dual infection within G. mellonella larvae.…”

“…Cryo-imaging was utilized to assess the dissemination of co-infection throughout the host over 48 h. By 24 h there was significant nodule formation and by 48 h there was extensive melanization and widespread nodule formation. Melanization of co-infected larvae is more systemic than that observed in mono-infection, which appears as localized nodules throughout the host [34, 39]. Previous results indicated that infection of larvae with a higher inoculum of C. albicans (5×10 5 larva −1 ) or S.…”

“…Previous results indicated that infection of larvae with a higher inoculum of C. albicans (5×10 5 larva −1 ) or S. aureus (2×10 6 larva −1 ) in mono-infection resulted in more cuticular melanization and larger granuloma (nodule)-type structure formation [34, 39]. This may indicate that co-infection, at a lower cell density, which ultimately produced a larger decrease in survival relative to mono-infection, may have activated a less robust immune response to co-infection (summarized in ) and via less cuticular melanization.…”

“…aureus [34], Streptococcus pneumoniae [35] and Enterococcus faecalis [36, 37]) and fungal (e.g. C. albicans [38, 39], A. fumigatus [40] and Cryptococcus neoformans [41]) pathogens as well as their interactions with the cellular and humoral immune response of larvae. Larvae were also used to assess the interaction between S.…”

Antifungal Activity of Anionic Defense Peptides: Insight into the Action of Galleria mellonella Anionic Peptide 2

“…In addition, FTIR and circular dichroism (CD) spectroscopy, as well as bioinformatics tools, were used for prediction of the properties and spatial structure of AP2 based on the peptide amino acid sequence. Considering the use of G. mellonella as a model organism in research on pathogenicity of different microorganisms, including C. albicans [33,34], the investigations on the AP2 antifungal action provide data on the role of this peptide in insect immune response against C. albicans, which are important for better understanding of the host-pathogen interactions in the G. mellonella-C. albicans system. In addition, this study contributes to an improved understanding of the antimicrobial properties of anionic peptides related to immunity.…”