Publications by authors named "Katy Soapi"

9 Publications

  • Page 1 of 1

High variance in community structure and ecosystem carbon stocks of Fijian mangroves driven by differences in geomorphology and climate.

Environ Res 2021 01 25;192:110213. Epub 2020 Sep 25.

School of Biological Sciences, The University of Queensland, St Lucia, QLD, 4067, Australia.

Mangrove ecosystems are particularly important for small island developing states of the Pacific, such as Fiji, which are at the forefront of the impacts of climate change. This is because of the ability of mangroves to mitigate storm surges and floods as well as their high carbon sequestration and storage capacity. However, there are few detailed studies on the spatial variation in mangrove structure and carbon stocks in Fiji, and this information is essential to support decision making by government and communities, enabling the development of effective mitigation and adaptation responses. We assessed mangrove forest structure in contrasting regions around Fiji's largest island, Viti Levu, within sites managed by indigenous (iTaukei) Fijians. Mangroves of the Ba, Nadroga-Navosa, and Rewa and Tailevu regions showed high variance in both structural complexity and ecosystem carbon stocks. Levels of variation were similar to that observed globally due to variable geomorphological and biophysical settings related to orographic rainfall, freshwater influx, tidal amplitude and cyclonic disturbances. High biomass, structurally complex forests occur on the wetter south-east coast (e.g. the Rewa Delta), while structurally uniform scrub mangroves dominate large areas of mangroves along the north-west (e.g. the Ba Delta) and west coast (e.g. the Tuva Delta). Mangroves of the Ba region displayed considerable damage from tropical cyclones, particularly in taller vegetation. All mangrove sites assessed were important reservoirs of carbon, with results when scaled to the spatial extent of mangroves in Fiji revealing that ecosystem carbon storage is disproportionate to area and equates to 73.3% of the carbon held within terrestrial rainforests, despite occupying just 7.3% of the total area. This underscores the importance of mangroves as valuable carbon sinks in Fiji and the need to develop incentives for improved conservation and restoration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.envres.2020.110213DOI Listing
January 2021

Seagrasses and seagrass habitats in Pacific small island developing states: Potential loss of benefits via human disturbance and climate change.

Mar Pollut Bull 2020 Nov 8;160:111573. Epub 2020 Sep 8.

Research Office, The University of the South Pacific, Suva, Fiji.

Seagrasses provide a wide range of services including food provision, water purification and coastal protection. Pacific small island developing states (PSIDS) have limited natural resources, challenging economies and a need for marine science research. Seagrasses occur in eleven PSIDS and nations are likely to benefit in different ways depending on habitat health, habitat cover and location, and species presence. Globally seagrass habitats are declining as a result of anthropogenic impacts including climate change and in PSIDS pressure on already stressed coastal ecosystems, will likely threaten seagrass survival particularly close to expanding urban settlements. Improved coastal and urban planning at local, national and regional scales is needed to reduce human impacts on vulnerable coastal areas. Research is required to generate knowledge-based solutions to support effective coastal management and protection of the existing seagrass habitats, including strenghened documentation the socio-economic and environmental services they provide. For PSIDS, protection of seagrass service benefits requires six priority actions: seagrass habitat mapping, regulation of coastal and upstream development, identification of specific threats at vulnerable locations, a critique of cost-effective restoration options, research devoted to seagrass studies and more explicit policy development.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.marpolbul.2020.111573DOI Listing
November 2020

Six novel species of the obligate marine actinobacterium , sp. nov., sp. nov., sp. nov., sp. nov., sp. nov. and sp. nov., and emended description of the genus .

Int J Syst Evol Microbiol 2020 Aug 23;70(8):4668-4682. Epub 2020 Jul 23.

Departamento de Microbiología y Genética, Campus Miguel de Unamuno, Universidad de Salamanca, 37007 Salamanca, Spain.

Ten representative actinobacterial strains isolated from marine sediments collected worldwide were studied to determine their taxonomic status. The strains were previously identified as members of the genus and shared >99 % 16S rRNA gene sequence similarity to the three currently recognized species. Comparative genomic analyses resulted in the delineation of six new species based on average nucleotide identity and digital DNA-DNA hybridization values below 95 and 70 %, respectively. The species status of the six new groups was supported by a core-genome phylogeny reconstructed from 2106 orthologs detected in 118 publicly available genomes. Chemotaxonomic and physiological studies were used to complete the phenotypic characterization of the strains. The fatty acid profiles contained the major components iso-C, C, iso- and anteiso C. Galactose and xylose were common in all whole-sugar patterns but differences were found between the six groups of strains. Polar lipid compositions were also unique for each species. Distinguishable physiological and biochemical characteristics were also recorded. The names proposed are sp. nov., CNY-202 (=DSM 108615=CECT 9739); sp. nov., CNT-569 (=DSM 108614=CECT 9740); sp. nov., CNY-666 (=DSM 108616=CECT 9738); sp. nov., CNT-150 (=DSM 45549=CECT 9741); sp. nov., CNT-138 (=DSM 45547=CECT 9742); and sp. nov., CNT-148 (=DSM 45548=CECT 9743).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1099/ijsem.0.004330DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7660244PMC
August 2020

Antimalarial Peptide and Polyketide Natural Products from the Fijian Marine Cyanobacterium .

Mar Drugs 2020 03 18;18(3). Epub 2020 Mar 18.

School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA.

A new cyclic peptide, kakeromamide B (), and previously described cytotoxic cyanobacterial natural products ulongamide A (), lyngbyabellin A (), 18-lyngbyaloside C (), and lyngbyaloside () were identified from an antimalarial extract of the Fijian marine cyanobacterium . Compounds and exhibited moderate activity against blood-stages with EC values of 0.89 and 0.99 µM, respectively, whereas was more potent with an EC value of 0.15 nM, respectively. Compounds , , and displayed moderate liver-stage antimalarial activity against liver schizonts with EC values of 1.1, 0.71, and 0.45 µM, respectively. The threading-based computational method FINDSITE predicted the binding of and to potentially druggable proteins of , prompting formulation of hypotheses about possible mechanisms of action. Kakeromamide B () was predicted to bind to several actin-like proteins and a sortilin protein suggesting possible interference with parasite invasion of host cells. When 1 was tested in a mammalian actin polymerization assay, it stimulated actin polymerization in a dose-dependent manner, suggesting that 1 does, in fact, interact with actin.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/md18030167DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7142784PMC
March 2020

Peyssonnosides A-B, Unusual Diterpene Glycosides with a Sterically Encumbered Cyclopropane Motif: Structure Elucidation Using an Integrated Spectroscopic and Computational Workflow.

J Org Chem 2019 07 18;84(13):8531-8541. Epub 2019 Jun 18.

Parker H. Petit Institute for Bioengineering and Bioscience , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States.

Two sulfated diterpene glycosides featuring a highly substituted and sterically encumbered cyclopropane ring have been isolated from the marine red alga Peyssonnelia sp. Combination of a wide array of 2D NMR spectroscopic experiments, in a systematic structure elucidation workflow, revealed that peyssonnosides A-B (1-2) represent a new class of diterpene glycosides with a tetracyclo [7.5.0.0.0] tetradecane architecture. A salient feature of this workflow is the unique application of quantitative interproton distances obtained from the rotating frame Overhauser effect spectroscopy (ROESY) NMR experiment, wherein the β-d-glucose moiety of 1 was used as an internal probe to unequivocally determine the absolute configuration, which was also supported by optical rotatory dispersion (ORD). Peyssonnoside A (1) exhibited promising activity against liver stage Plasmodium berghei and moderate antimethicillin-resistant Staphylococcus aureus (MRSA) activity, with no cytotoxicity against human keratinocytes. Additionally, 1 showed strong growth inhibition of the marine fungus Dendryphiella salina indicating an antifungal ecological role in its natural environment. The high natural abundance and novel carbon skeleton of 1 suggests a rare terpene cyclase machinery, exemplifying the chemical diversity in this phylogenetically distinct marine red alga.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.joc.9b00884DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6614789PMC
July 2019

Antibacterial Oligomeric Polyphenols from the Green Alga Cladophora socialis.

J Org Chem 2019 05 3;84(9):5035-5045. Epub 2019 Apr 3.

Aquatic Chemical Ecology Center , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States.

A series of oligomeric phenols including the known natural product 3,4,3',4'-tetrahydroxy-1,1'-biphenyl (3), the previously synthesized 2,3,8,9-tetrahydroxybenzo[ c]chromen-6-one (4), and eight new related natural products, cladophorols B-I (5-12), were isolated from the Fijian green alga Cladophora socialis and identified by a combination of NMR spectroscopy, mass spectrometric analysis, and computational modeling using DFT calculations. J-resolved spectroscopy and line width reduction by picric acid addition aided in resolving the heavily overlapped aromatic signals. A panel of Gram-positive and Gram-negative pathogens used to evaluate pharmacological potential led to the determination that cladophorol C (6) exhibits potent antibiotic activity selective toward methicillin-resistant Staphylococcus aureus (MRSA) with an MIC of 1.4 μg/mL. Cladophorols B (5) and D-H (7-11) had more modest but also selective antibiotic potency. Activities of cladophorols A-I (4-12) were also assessed against the asexual blood stages of Plasmodium falciparum and revealed cladophorols A (4) and B (5) to have modest activity with EC values of 0.7 and 1.9 μg/mL, respectively.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.joc.8b03218DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6503470PMC
May 2019

Investigations of the marine flora and fauna of the Fiji Islands.

Nat Prod Rep 2012 Dec 14;29(12):1424-62. Epub 2012 Sep 14.

Centre for Drug Discovery and Conservation, Institute of Applied Sciences, The University of the South Pacific, Suva, Fiji.

Over the past 30 years, approximately 140 papers have been published on marine natural products chemistry and related research from the Fiji Islands. These came about from studies starting in the early 1980s by the research groups of Crews at the University of California Santa Cruz, Ireland at the University of Utah, Gerwick from the Scripps Institution of Oceanography, the University of California at San Diego and the more recent groups of Hay at the Georgia Institute of Technology (GIT) and Jaspars from the University of Aberdeen. This review covers both known and novel marine-derived natural products and their biological activities. The marine organisms reviewed include invertebrates, plants and microorganisms, highlighting the vast structural diversity of compounds isolated from these organisms. Increasingly during this period, natural products chemists at the University of the South Pacific have been partners in this research, leading in 2006 to the development of a Centre for Drug Discovery and Conservation (CDDC).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c2np20055dDOI Listing
December 2012

Stereoselective synthesis of N-alkylaziridines from N-chloroamines.

Chem Commun (Camb) 2006 Nov 5(41):4338-40. Epub 2006 Sep 5.

School of Chemical Sciences & Pharmacy, UEA, Norwich, UK NR4 7TJ.

We report the first racemic and stereoselective synthesis of cis- and trans-N-alkylaziridines viaN-chloroamines; using this methodology an N-3,4,5-trimethoxybenzylaziridine was synthesised and efficiently cleaved, affording the corresponding NH aziridine in high yield.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/b608504kDOI Listing
November 2006

Expedient synthesis of substituted (S)-N-(alpha-methylbenzyl)aziridines.

Chem Commun (Camb) 2006 Sep 11(33):3513-5. Epub 2006 Jul 11.

School of Chemical Sciences & Pharmacy, University of East Anglia, Norwich, Norfolk, UK.

We report for the first time that after O-acylation the conjugate addition products of (S)-N-(alpha-methylbenzyl)hydroxylamine undergo an efficient diastereoselective 3-exo-tet ring-closure reaction affording 2- and 2,3-disubstituted-N-alkylaziridines in good to excellent yields.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/b606033aDOI Listing
September 2006