Browsing by Author "Davies-Coleman, Michael T."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Antibacterial activities of bacteria isolated from the marine sponges Isodictya compressa and Higginsia bidentifera collected from Algoa Bay, South Africa
    (MDPI AG, 2017) Matobole, Relebohile Matthew; van Zyl, Leonardo Joaquim; Parker-Nance, Shirley; Davies-Coleman, Michael T.; Trindade, Marla
    Due to the rise inmulti-drug resistant pathogens and other diseases, there is renewed interest in marine sponge endosymbionts as a rich source of natural products (NPs). The South African marine environment is rich in marine biota that remains largely unexplored and may represent an important source for the discovery of novel NPs.We first investigated the bacterial diversity associated with five South African marine sponges, whose microbial populations had not previously been investigated, and select the two sponges (Isodictya compressa and Higginsia bidentifera) with highest species richness to culture bacteria. By employing 33 different growth conditions 415 sponge-associated bacterial isolates were cultured and screened for antibacterial activity. Thirty-five isolates showed antibacterial activity, twelve of which exhibited activity against the multi-drug resistant Escherichia coli 1699, implying that some of the bioactive compounds could be novel. Genome sequencing of two of these isolates confirmed that they harbour uncharacterized biosynthetic pathways that may encode novel chemical structures.
  • Thumbnail Image
    Item
    Hyphenated LC-ICP-MS/ESI-MS identification of halogenated metabolites in South African marine ascidian extracts
    (The South African Chemical Institute, 2018) Bromley, Candice L.; Raab, Andrea; Parker-Nance, Shirley; Beukes, Denzil R.; Jaspars, Marcel; Davies-Coleman, Michael T.
    Extracts of 13 species of marine ascidian collected in Algoa Bay were analyzed by LC-ICP-MS/ESI-MS. This technique allows parallel analysis of the molecular species and the presence of certain elements. The LC-ICP-MS/ESI-MS technique was used to target iodinated metabolites in this study. Three ascidian species afforded the known 3,5–diiodo-4-methoxyphenethylamine (12), which was confirmedby the isolation of this metabolite fromAplidium monile.MS also suggested the presence of theknown 3,5–dibromo-4-methoxyphenethylamine (10) and the new 3-bromo-5–iodo-4-methoxyphenethylamine (11) in the A. monile extract. The presence of the known 3,5-dibromotetramethyltyrosine (21) and the new 3-iodotetramethyltyrosine (23) in extracts of an unidentified Didemnum species was similarly proposed from MS evidence. This is the first report of the occurrence of iodinated metabolites in South African marine invertebrates.