dc.contributor.advisor | Carroll, Anthony | |
dc.contributor.advisor | Wilson, Jennifer | |
dc.contributor.author | Habener, Leesa | |
dc.date.accessioned | 2019-03-20T04:41:15Z | |
dc.date.available | 2019-03-20T04:41:15Z | |
dc.date.issued | 2018-10 | |
dc.identifier.doi | 10.25904/1912/1916 | |
dc.identifier.uri | http://hdl.handle.net/10072/382720 | |
dc.description.abstract | The work completed in this PhD thesis investigates and compares the chemical
and biological variation of marine sponges. A comprehensive literature review of
compounds isolated from the family Mycalidae was completed to characterise the known
chemical diversity of the family. In total 190 compounds were reported from 40 taxa
comprising a range of structure classes that include alkaloids, polyketides, terpene
endoperoxides, peptides, and lipids. The family is identified as a good target for
biodiscovery; macrocyclic polyketides display potent cytotoxicity (LC50 <1 μM), and
alkaloids (pyrrole derivatives) moderate cytotoxicity (LC50 1 – 20 μM). The pyrrole
alkaloids and cyclic peroxides are phylogenetically restricted to sponges and could
provide a good candidate for chemotaxonomic markers.
Morphological taxonomy of sponges is complicated by a lack of clear diagnostic
morphological characters, and chemical compounds are a useful set of characters that
can be explored. A 2D 1H-13C HSQC spectroscopic profiling technique was developed to
assess the chemical variation of sponge extracts. HSQC spectroscopic profiles (n=28)
comprising 6 species of three sponge families (Microcionidae, Mycalidae, and
Raspailiidae) showed consistent chemical profiles within family and over geographic
scales ranging from approximately 30 to 1700 km. Comparison of chemical shift values
to the literature resulted in the identification of chemical compounds that contain
chemical moieties indicated by the diagnostic H-C signals. LC-MS/MS enabled
identification of 22 known compounds, of which one, mycalamide A, was a sponge
natural product. HSQC spectroscopic profiling provides a powerful technique to
characterise the chemical moiety diversity that can be applied to both sponge taxonomy
and natural products discovery.
Molecular approaches have also been applied for the identification of sponge
species. Three mitochondrial markers (CO1, SP1, and SP2) were amplified for a
collection of sponges (n=144) from the Great Barrier Reef, Australia to group samples
into sets that share genetic similarity. This resulted in the establishment 34 molecular
operational taxonomic units (MOTUs) and 27 of these MOTUs were assigned order-level
identifications using phylogenetic reconstructions. Initially low amplification rates across
all three markers (ranging from 17.9 – 34.0 %) were improved after cleaning DNA
extracts with phenol-chloroform and reattempting amplification (increased to 60.4 – 75.5
%) for a subset of samples (n=106) indicating the presence of chemical inhibitors.
Integrative taxonomic approaches combining multiple datasets have been
proposed to assist sponge taxonomy. The developed HSQC spectroscopic profiling approach was applied to a subset (n=56) of the same samples collected from the Great
Barrier Reef. Analysis of spectroscopic profiles allowed the identification of three
chemical operational taxonomic units (ChOTUs) that displayed high chemical similarity.
Searching the literature resulted in the identification of chemical compounds that contain
chemical moieties indicated by the distinguishing H-C signals. The morphological
operational taxonomic units (OTUs) established at time of collection, and the MOTUs
and ChOTUs established here, were used to propose three putative taxa as a first step
in species delimitation.
Overall this thesis proposes a HSQC spectroscopic profiling method that can be
applied to sponge taxonomy as well as to natural products discovery efforts.
Spectroscopic profiles can be used to de-replicate samples and target samples
possessing unique chemical profiles. Through this process sponge families were shown
to display consistent spectroscopic profiles over large geographic scales; an important
finding for both sponge chemical taxonomy and biodiscovery projects. Additionally, this
thesis results in the proposal of three putative taxa on the basis of comparing chemical, morphological, and molecular variation. | |
dc.language | English | |
dc.language.iso | en | |
dc.publisher | Griffith University | |
dc.publisher.place | Brisbane | |
dc.subject.keywords | Chemical variation | |
dc.subject.keywords | Biological variation | |
dc.subject.keywords | Marine sponges | |
dc.subject.keywords | HSQC spectroscopic profiling | |
dc.subject.keywords | Spectroscopic profiles | |
dc.title | Investigating and comparing chemical and biological variation of marine sponges (phylum Porifera) | |
dc.type | Griffith thesis | |
gro.faculty | Science, Environment, Engineering and Technology | |
gro.rights.copyright | The author owns the copyright in this thesis, unless stated otherwise. | |
gro.hasfulltext | Full Text | |
dc.contributor.otheradvisor | Hooper, John | |
dc.contributor.otheradvisor | Hall, Kathryn | |
dc.contributor.otheradvisor | Wilmer, Jessica Worthington | |
gro.thesis.degreelevel | Thesis (PhD Doctorate) | |
gro.thesis.degreeprogram | Doctor of Philosophy (PhD) | |
gro.department | School of Environment and Sc | |
gro.griffith.author | Habener, Leesa | |