Project description:Staphylococcus epidermidis, the common inhabitant of human skin and mucosal surfaces has emerged as an important pathogen in patients receiving surgical implants and medical devices. Entering the body via surgical sites and colonizing the medical devices through formation of multi-layered biofilms it leads to refractory and persistent device-related infections (DRIs). Staphylococcal proportions within biofilms are more tolerant to antibiotics and immune responses, and thus are hard-to-treat. The consequent morbidity and mortality, and economic losses in health care systems has strongly necessitated the need for development of new anti-bacterial and anti-biofilm based therapeutics. In this study, we describe the biological activity of a marine sponge-derived Streptomyces sp. SBT348 extract in restraining staphylococcal growth and biofilm formation on polystyrene, glass, medically relevant titan metal and silicone surfaces. A bio-assay guided fractionation was performed to isolate the active compound (C3) from the crude SBT348 extract. Our results demonstrated that C3 effectively inhibits the growth (MIC: 31.25 µg/ml) and biofilm formation (sub-MIC range: 1.95-<31.25 µg/ml) of S. epidermidis RP62A in vitro. Chemical characterization of C3 by heat and enzyme treatments, and High-Resolution Fourier Transform Mass Spectrometry (HRMS) revealed its heat-stable and non-proteinaceous nature, and high molecular weight (1258. 3257 Da). Cytotoxicity profiling of C3 in vitro on mouse fibroblast (NIH/3T3) and macrophage (J774.1) cell lines, and in vivo on the greater wax moth larvae Galleria melonella revealed its non-toxic nature at the effective dose. Transcriptome analysis of C3 treated-S. epidermidis RP62A has further unmasked the negative effect of C3 on central metabolism (carbon, amino acid and protein, lipids, nucleotide and energy) suggesting its mode of action. Taken together, these findings suggest that C3 could be possibly used as antibacterial and antibiofilm coatings on medically-relevant surfaces and prevent the relapsing staphylococcal DRIs.
Project description:Vertebrates have highly methylated genomes at CpG positions while most invertebrates have sparsely methylated genomes. Therefore, hypermethylation is considered a major innovation that shaped the genome and the regulatory roles of DNA methylation in vertebrates. However, here we report that the marine sponge Amphimedon queenslandica, belonging to one of the earliest branching animal lineages, has evolved a hypermethylated genome with remarkable similarities to that of a vertebrate. Despite major differences in genome size and architecture, independent acquisition of hypermethylation reveal common distribution patterns and repercussions for genome regulation between both lineages. Genome wide depletion of CpGs is counterbalanced by CpG enrichment at unmethylated promoters, mirroring CpG islands. Furthermore, a subset of CpG-bearing transcription factor motifs are enriched at Amphimedon unmethylated promoters. We find that the animal-specific transcription factor NRF has conserved methyl-sensitivity over 700 million years, indicating an ancient cross-talk between transcription factors and DNA methylation. Finally, the sponge shows vertebrate-like levels of 5-hydroxymethylcytosine, the oxidative derivative of cytosine methylation involved in active demethylation. Hydroxymethylation is concentrated in regions that are enriched for transcription factor motifs and show developmentally dynamic demethylation. Together, these findings push back the links between DNA methylation and its regulatory roles to the early steps of animal evolution. Thus, the Amphimedon methylome challenges the prior hypotheses about the origins of vertebrate genome hypermethylation and its implications for regulatory complexity.