Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023)

The research is designed to continue to identify novel organo-bromine (OBCs) and organo-iodine (OICs) compounds by use of effect-directed fractionation and identification to determine biological activities of novel compounds. A range of functional bioassays including live cell arrays will be used to identify molecular pathways affected by the most active classes of compounds. A “pull-down” approach that will combine ultra-high resolution mass spectrometry with proteomics will be developed to identify molecular targets of novel OBCs and OIs. The proposed research has several specific objectives: 1) identify and quantify novel OBCs and OICs in a range of marine and freshwater environments; 2) use a mass balance (on Br and I) approach to determine what additional OBCs and OICs might be present and 3) use bioassays to determine the toxicity and potential beneficial uses of novel OBCs and OICs. The proposed research program will focus initially on the base of the food chain, including marine algae and invertebrates such as sponges and corals. OBCs will be identified by use of a combination of targeted and un-targeted mass spectrometry, including ultra-high resolution mass spectrometry UHR LC/MS (OrbiTrap) and triple quadrupole tandem mass spectrometry (LC-MS/MS), LC quadrupole-time of flight mass spectrometry (Q-ToF) and high resolution GC High Resolution Mass spectrometry (HRGC-HRMS). Total Br (TBr) and total iodine (TI) will be determined by Instrumental Neutron Activation Analysis (INAA) of either crude samples or organic solvent extracts. Accurate masses and formulas will be determined by M1 and structures elucidated by use of M2 data. Concentrations of known synthetic OBCs and OICs and those compounds that have been suggested as replacement flame retardants will be determined. Sufficient quantities of unknown compounds will be extracted and purified by preparative HPLC. The concentrated isolates will then be subjected to standard methods such as UV and spectrometry and IR spectroscopy and elemental analyses to help elucidate and or confirm structures. Once a structure has been confirmed, a synthesis procedure can be developed and greater quantities of pure compounds made. Once greater masses of material are available they will be subjected to a range of bioassays to determine: 1) their toxic mode of action and threshold for effects and a second set of bioassays to determine their potential utility as therapeutic agents. In addition to screening for toxicity and potential beneficial uses, the potential ecological and or physiological reasons for their production will be investigated. This will be done by use of a reverse-engineering screening of microbial cultures, based on the presence or absence of enzymes in pathways of syntheses of specific compounds. If compounds are determined to be too toxic, they will not be tested farther for therapeutic properties.