RESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) infections are increasingly causing morbidity and mortality; thus, drugs with multifunctional efficacy against MRSA are needed. We extracted a novel compound from the halophilic Pseudomonas aeruginosa using an ethyl acetate (HPAEtOAcE). followed by purification and structure elucidation through HPLC, LCMS, and 1H and 13C NMR, revealing the novel 5-(1H-indol-3-yl)-4-pentyl-1,3-oxazole-2-carboxylic acid (Compound 1). Molecular docking of the compound against the MRSA PS (pantothenate synthetase) protein was confirmed using the CDOCKER algorithm in BDS software with specific binding to the amino acids Arg (B:188) and Lys (B:150) through covalent hydrogen bonding. Molecular dynamic simulation of RMSD revealed that the compound-protein complex was stabilized. The proficient bioactivities against MRSA were attained by the HPAEtOAcE, including MIC and MBCs, which were 0.64 and 1.24 µg/mL, respectively; 100% biomass inhibition and 99.84% biofilm inhibition were observed with decayed effects by CLSM and SEM at 48 h. The hla, IrgA, and SpA MRSA genes were downregulated in RT-PCR. Non-hemolytic and antioxidant potential in the DPPH assay were observed at 10 mg/mL and IC50 29.75 ± 0.38 by the HPAEtOAcE. In vitro growth inhibition assays on MRSA were strongly supported by in silico molecular docking; Lipinski's rule on drug-likeness and ADMET toxicity prediction indicated the nontoxic nature of compound.
RESUMO
A lichen is a composite organism formed of algae or cyanobacteria that live in a mutually advantageous symbiotic relationship with the filaments (hyphae) of fungus. Three lichen samples were obtained from diverse sites at a terrestrial habitat located in Coimbatore and coastal habitats located in Kanyakumari and Nagapattinam districts of Tamil Nadu. Amplification and sequencing of 16S rRNA V3-V4 regions were used for metagenomic study. Aside from the Next-Generation Sequencing data (NGS), distinct types of lichen microbiome profiles were clearly revealed. The bacterial diversity in the lichen genera of Roccella montagnei growing in coastal and terrestrial environments was further investigated using common and unique operational taxonomic units (OTUs) and the QIIME pipeline (1.9.1). Using similarity clustering, the heat map analysis depicts the abundance information of chosen OTUs as well as the similarity and difference between OTUs and lichen samples. Using multiple methods, the alpha and beta diversity analysis revealed that there were differences in all of the samples. However, UPGMA tree inference of comparable bacterial community in coastal habitat lichen samples compared to terrestrial habitat validates their evolutionary lineage. As a result, the bacterial population associated with corticolous lichen is dependent on geographic locations, growth substrate, and climatic circumstances of similar lichen genera produced in different habitats and tree substrates.
