Potential for biocontrol of melanized fungi by actinobacteria isolated from intertidal region of Ilha Do Mel, Paraná, Brazil

Abstract

Actinobacteria occur in many environments and have the capacity to produce secondary metabolites with antibiotic potential. Identification and taxonomy of actinobacteria that produce antimicrobial substances is essential for the screening of new compounds, and sequencing of the 16S region of ribosomal DNA (rDNA), which is conserved and present in all bacteria, is an important method of identification. Melanized fungi are free-living organisms, which can also be pathogens of clinical importance. This work aimed to evaluate growth inhibition of melanized fungi by actinobacteria and to identify the latter to the species level. In this study, antimicrobial activity of 13 actinobacterial isolates from the genus Streptomyces was evaluated against seven melanized fungi of the genera Exophiala, Cladosporium, and Rhinocladiella. In all tests, all actinobacterial isolates showed inhibitory activity against all isolates of melanized fungi, and only one actinobacterial isolate had less efficient inhibitory activity. The 16S rDNA region of five previously unidentified actinobacterial isolates from Ilha do Mel, Paraná, Brazil, was sequenced; four of the isolates were identified as Streptomyces globisporus subsp. globisporus, and one isolate was identified as Streptomyces aureus. This work highlights the potential of actinobacteria with antifungal activity and their role in the pursuit of novel antimicrobial substances.

Profiling of the Conjunctival Bacterial Microbiota Reveals the Feasibility of Utilizing a Microbiome-Based Machine Learning Model to Differentially Diagnose Microbial Keratitis and the Core Components of the Conjunctival Bacterial Interaction Network

“…Actinobacteria , a common bacterial genus, can synthesize numerous secondary metabolites that have antimicrobial, antiviral, antiparasitic, antioxidant, anticancer, and neurological activities. ( Valliappan et al., 2014 ; Dalitz et al., 2017 ) As shown by LEfSe, compared with healthy subjects, Actinobacteria was significantly reduced in the conjunctival microbiota of MK eyes, and our previous study ( Ren et al., 2021 ) and that of Shivaji et al. ( Shivaji et al., 2021 ) also reported that Actinobacteria is significantly reduced in the conjunctival microbiota of the diseased eyes of BK patients.…”

Profiling of Diagnostic Information of and Latent Susceptibility to Bacterial Keratitis From the Perspective of Ocular Bacterial Microbiota

“…However, Yin-Yang imbalances enable people to develop certain disease. Accordingly, in this study, Yin stood for probiotics such as Corynebacterium and Actinobacteria , for Corynebacterium mastiditis ( St Leger et al., 2017 ) has been previously demonstrated to elicit IL-17 response from γδ T cells in the ocular mucosa to resist bacterial and fungal infections on the murine ocular surface, and Actinobacteria ( Valliappan et al., 2014 ; Dalitz et al., 2017 ) has proved to synthesize a series of secondary metabolites, which have antimicrobial, anti-viral, antiparasitic, antioxidant, anticancer, and neurological activities. Yin also represented a bunch of nonpathogenic bacteria with undiscovered benefits.…”