ORCID Profile
0000-0002-0217-6021
Current Organisations
Macquarie University
,
University of New South Wales - Randwick Campus
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Biochemistry and Cell Biology | Biological And Medical Chemistry | Biotechnology Not Elsewhere Classified | Structural Chemistry | Medicinal and Biomolecular Chemistry | Organic Chemical Synthesis | Biologically Active Molecules | Instruments And Techniques | Proteomics and Intermolecular Interactions (excl. Medical Proteomics) | Other Physical Sciences | Analytical Chemistry | Natural Products Chemistry | Bioinorganic Chemistry | Optical Physics | Organic Chemical Synthesis | Analytical Spectrometry | Theoretical and Computational Chemistry | Physical Chemistry (Incl. Structural) | Proteins and Peptides | Molecular Targets | Biochemistry and Cell Biology not elsewhere classified | Biological Physics | Theoretical And Computational Chemistry Not Elsewhere Classified | Analytical Biochemistry | Analytical Chemistry Not Elsewhere Classified | Organic Chemistry not elsewhere classified | Animal Protection (Pests and Pathogens) | Photonics, Optoelectronics and Optical Communications
ANZSRC Socio-Economic Objective (SEO)
Chemical sciences | Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Biological Sciences | Higher education | Industrial instrumentation | Biological sciences | Land and water management | Food safety | Infectious Diseases | Animal Protection Chemicals | Human Diagnostics | Horticultural Crops not elsewhere classified | Medical Instruments | Expanding Knowledge in the Physical Sciences | Scientific Instruments |
Related Links
Publications
Site-directed mutagenesis and high-resolution NMR-spectroscopy of the active-site of porphobilinogen deaminase
Publisher: Elsevier BV
Date: 1990
Combinatorial synthesis of new fluorescent scaffolds using click chemistry
Publisher: Elsevier BV
Date: 2021
Daptomycin suppresses tumor migration and angiogenesis via binding to ribosomal protein S19 in humans
Publisher: Springer Science and Business Media LLC
Date: 12-07-2021
DOI: 10.1038/S41429-021-00446-X
Abstract: We have previously reported that daptomycin (DAP), a last resort antibiotic, binds to ribosomal protein S19 (RPS19) in humans and exhibits selective anti-cancer activity against MCF7 breast cancer cells. Here, we investigated the role of RPS19 in the anti-cancer effects of DAP and have found that DAP does not induce autophagy, apoptosis or cell viability but does reduce cell proliferation. Our results suggest that an extraribosomal function of RPS19 involves the regulation of vascular endothelial growth factor (VEGF) but not EGF, PDGF or FGF. Engagement of RPS19 by DAP was shown by CETSA and ITDRF
Solution Structure of FK 506 from Nuclear Magnetic Resonance and Molecular Dynamics
Publisher: American Chemical Society (ACS)
Date: 12-1990
DOI: 10.1021/JA00181A078
Modern Methods for the Isolation of Natural Product Receptors
Publisher: Elsevier
Date: 2010
Long-chain α,ω-bisisothiocyanates from a marine sponge
Publisher: Elsevier BV
Date: 1987
Ketimine reductase/CRYM catalyzes reductive alkylamination of α-keto acids, confirming its function as an imine reductase
Publisher: Springer Science and Business Media LLC
Date: 15-07-2015
DOI: 10.1007/S00726-015-2044-8
Abstract: Recently, crystalized mouse ketimine reductase/CRYM complexed with NADPH was found to have pyruvate bound in its active site. We demonstrate that the enzyme binds α-keto acids, such as pyruvate, in solution, and catalyzes the formation of N-alkyl-amino acids from alkylamines and α-keto acids (via reduction of imine intermediates), but at concentrations of these compounds not expected to be encountered in vivo. These findings confirm that, mechanistically, ketimine reductase/CRYM acts as a classical imine reductase and may explain the finding of bound pyruvate in the crystallized protein.
Chemistry of sponges, VI. Scalarane sesterterpenes from hyatella intest1nalis
Publisher: American Chemical Society (ACS)
Date: 03-1989
DOI: 10.1021/NP50062A012
Hydrolysis rates of alkyl and aryl sulfinamides: evidence of general acid catalysis
Publisher: Elsevier BV
Date: 10-2007
Room-Temperature Dual Fluorescence of a Locked Green Fluorescent Protein Chromophore Analogue
Publisher: American Chemical Society (ACS)
Date: 17-12-2020
DOI: 10.1021/JACS.9B05096
Abstract: A structurally locked green fluorescent protein (GFP) chromophore with a phenyl group at C(2) of the imidazolone has been synthesized. Rotation around the exocyclic double bond is hindered, resulting in room-temperature fluorescence. The quantum yield in water is 500 times greater than that of unlocked analogues. Unlike the methyl-substituted analogue, the phenyl analogue exhibits a dual emission (cyan and red) that can be used for ultrasensitive ratiometric measurements and fluorescence microscopy. To explain this dual emission, DFT calculations were carried out along with fluorescence upconversion experiments. The
Chemical proteomics, an integrated research engine for exploring drug-target-phenotype interactions
Publisher: Springer Science and Business Media LLC
Date: 09-01-2018
Timing and Mechanistic Implications of Regiospecific Carbonyl Oxygen Isotope Exchange during Vitamin B12 Biosynthesis
Publisher: American Chemical Society (ACS)
Date: 12-1991
DOI: 10.1021/JA00026A047
Chemistry of sponges, III. manoalide monoacetate and thorectolide monoacetate, two new sesterterpenoids from thorectandra excavatus
Publisher: American Chemical Society (ACS)
Date: 03-1988
DOI: 10.1021/NP50056A026
The chemical gymnastics of enterocin
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0OB01099E
Abstract: Stereo ergence in Nature encapsulates both enzymatic (biosynthetic) and non-enzymatic (chemical) ersification of natural product scaffolds arising from a single biosynthetic pathway.
Benzylic coupling constants [4J(MeCCH)] for a series of 4‐Methylbenzo[h]quinolines and 4‐Methylbenzo[h]quinolin‐2‐ones
Publisher: Wiley
Date: 08-1986
Daptomycin, a last-resort antibiotic, binds ribosomal protein S19 in humans
Publisher: Springer Science and Business Media LLC
Date: 12-2017
The constituents of marine sponges. II the isolation from aplysilla rosea (dendroceratida) of (5R*, 7S*, 8R*, 9S*, 10R*, 13S*, 14S*, 15S*)-15, 17-Epoxy-17-hydroxy-16-oxospongian-7-yl butyrate (aplyroseol-1) and related diterpenes (aplyroseol-2 to -6)
Publisher: CSIRO Publishing
Date: 1985
DOI: 10.1071/CH9861629
Abstract: From the red-pink encrusting marine sponge Aplysilla rosea Barrois eight spongian diterpenes were isolated. Aplyroseol-1 was shown by spectroscopic methods to be (5R*,7S*,8R*,9S*,10R*,13S*,14S*,15S*)-15,17-epoxy-17-hydroxy-16-oxospongian-7-yl butyrate (5) and aplyroseol -2 to -6 to be (6)-(10) respectively. Two lactones (11) and (12), ambliofuran and its hexahydro derivative were also identified. A steroid fraction was also isolated.
Mechanism of reversible fluorescent staining of protein with epicocconone
Publisher: American Chemical Society (ACS)
Date: 17-05-2005
DOI: 10.1021/OL050665B
Abstract: [reaction: see text] Epicocconone is the active ingredient in Deep Purple Total Protein Stain and responsible for the apparent noncovalent staining of proteins in polyacrylamide gel and electroblots. Reaction of epicocconone with amines has shown that epicocconone reacts reversibly with primary amines to produce a highly fluorescent enamine that is readily hydrolyzed by base or strong acid such as in conditions used in post-electrophoretic analysis such as peptide mass fingerprinting or Edman degradation.
Multiple O-glycoforms on the spore coat protein sp96 in Dictyostelium discoideum. Fuc(α1-3)GlcNAc-α-1-P-Ser is the major modification
Publisher: Elsevier BV
Date: 04-2000
Biosynthesis of Isocyanoterpenes in Sponges
Publisher: American Chemical Society (ACS)
Date: 04-1989
DOI: 10.1021/JO00270A016
Nitrogenous Bisabolene Sesquiterpenes from Marine Invertebrates
Publisher: American Chemical Society (ACS)
Date: 12-1986
DOI: 10.1021/JO00376A015
Isocyanoneopupukeanane, a New Tricyclic Sesquiterpene from a Sponge
Publisher: American Chemical Society (ACS)
Date: 04-1989
DOI: 10.1021/JO00270A017
132,173-Cyclopheophorbide enol, the first porphyrin isolated from a sponge
Publisher: Elsevier BV
Date: 1986
Excited state dynamics of brightly fluorescent second generation epicocconone analogues
Publisher: American Chemical Society (ACS)
Date: 06-05-2015
Abstract: The natural product epicocconone, owing to its unique fluorescence properties, has been developed into a range of products used in biotechnology, especially proteomics. However, its weak green fluorescence in its native state, while advantageous for proteomics applications, is a disadvantage in other applications that require two-color readouts. Here we report the photophysical characterization of two brightly fluorescent analogues of epicocconone. These analogues, with naphthyl or pyridyl groups replacing the heptatriene chain, resulted in bright fluorescence in both the native state and the long Stokes shifted enamine. Time-resolved fluorescence studies and DFT calculations were carried out to understand the excited state processes involved in fluorescence. Results showed the p-chloro group on the pyridyl is responsible for the high fluorescence of the native fluorophore. The application of one of these compounds for staining electrophoresis gels is exemplified.
Insights into Enzyme Catalysis and Thyroid Hormone Regulation of Cerebral Ketimine Reductase/μ-Crystallin Under Physiological Conditions
Publisher: Springer Science and Business Media LLC
Date: 05-2015
DOI: 10.1007/S11064-015-1590-5
Abstract: Mammalian ketimine reductase is identical to μ-crystallin (CRYM)-a protein that is also an important thyroid hormone binding protein. This dual functionality implies a role for thyroid hormones in ketimine reductase regulation and also a reciprocal role for enzyme catalysis in thyroid hormone bioavailability. In this research we demonstrate potent sub-nanomolar inhibition of enzyme catalysis at neutral pH by the thyroid hormones L-thyroxine and 3,5,3'-triiodothyronine, whereas other thyroid hormone analogues were shown to be far weaker inhibitors. We also investigated (a) enzyme inhibition by the substrate analogues pyrrole-2-carboxylate, 4,5-dibromopyrrole-2-carboxylate and picolinate, and (b) enzyme catalysis at neutral pH of the cyclic ketimines S-(2-aminoethyl)-L-cysteine ketimine (owing to the complex nomenclature trivial names are used for the sulfur-containing cyclic ketimines as per the original authors' descriptions) (AECK), Δ(1)-piperideine-2-carboxylate (P2C), Δ(1)-pyrroline-2-carboxylate (Pyr2C) and Δ(2)-thiazoline-2-carboxylate. Kinetic data obtained at neutral pH suggests that ketimine reductase/CRYM plays a major role as a P2C/Pyr2C reductase and that AECK is not a major substrate at this pH. Thus, ketimine reductase is a key enzyme in the pipecolate pathway, which is the main lysine degradation pathway in the brain. In silico docking of various ligands into the active site of the X-ray structure of the enzyme suggests an unusual catalytic mechanism involving an arginine residue as a proton donor. Given the critical importance of thyroid hormones in brain function this research further expands on our knowledge of the connection between amino acid metabolism and regulation of thyroid hormone levels.
Constituents of eupomatia species. x: The synthesis of 6-methoxy-5-methyl-benzo[h]pyrrolo[4, 3, 2-de]quinolin-4(5h)-one (eupolauramine)
Publisher: CSIRO Publishing
Date: 1984
DOI: 10.1071/CH9841271
Abstract: Two syntheses of 6-methoxy-5-methylbenzo[h]pyrrolo[4,3,2-de]quinolin-4(5H)-one (eupolauramine) starting from 4-methoxynaphthylamine are described. One synthesis is highly efficient.
Structural Characterization and Spatial Mapping of Tetrodotoxins in Australian Polyclads
Publisher: MDPI AG
Date: 19-12-2022
DOI: 10.3390/MD20120788
Abstract: Tetrodotoxin (TTX) is a potent marine neurotoxin that occurs in several Australian phyla, including pufferfish, toadfish, gobies, and the blue-ringed octopus. These animals are partially immune, and TTX is known to bioaccumulate and subject to trophic transfer. As such, it could be more ubiquitously distributed in animals than is currently known. Flatworms of the order Polycladida are commonly occurring invertebrates in intertidal ecosystems and are especially erse in Australian waters. While TTX has been identified in polyclads from Japan and New Zealand, Australian species have yet to be tested. In this study, several eastern Australian polyclad flatworm species from the suborders Cotylea and Acotylea were tested for TTX and analogs by HILIC-HRMS to understand the distribution of this toxin within these suborders. Herein, we report the detection of TTX and some known analogs in polyclad species, one of which is a pest to shellfish aquaculture. We also report, for the first time, the application of MALDI mass spectrometry imaging utilized to map TTX spatially within the intestinal system of polyclads. The identification of TTX and its analogs in Australian flatworms illustrates a broader range of toxic flatworms and highlights that analogs are important to consider when studying the distributions of toxins in animals.
The structure of sirohydrochlorin I, a dimethylisobacteriochlorin derived from uroporphyrinogen I
Publisher: Royal Society of Chemistry (RSC)
Date: 1989
DOI: 10.1039/C39890000522
Probing site specificity of DNA binding metallointercalators by NMR spectroscopy and molecular modeling
Publisher: American Chemical Society (ACS)
Date: 16-03-2001
DOI: 10.1021/BI001655F
Abstract: The molecular recognition of oligonucleotides by chiral ruthenium complexes has been probed by NMR spectroscopy using the template Delta-cis-alpha- and Delta-cis-beta-[Ru(RR-picchxnMe(2)) (bidentate)](2+), where the bidentate ligand is one of phen (1,10-phenanthroline), dpq (dipyrido[3,2-f:2',3'-h]quinoxaline), or phi (9,10-phenanthrenequinone diimine) and picchxnMe(2)() is N,N'-dimethyl-N,N'-di(2-picolyl)-1,2-diaminocyclohexane. By varying only the bidentate ligand in a series of complexes, it was shown that the bidentate alone can alter binding modes. DNA binding studies of the Delta-cis-alpha-[Ru(RR-picchxnMe(2))(phen)](2+) complex indicate fast exchange kinetics on the chemical shift time scale and a "partial intercalation" mode of binding. This complex binds to [d(CGCGATCGCG)](2) and [d(ATATCGATAT)](2) at AT, TA, and GA sites from the minor groove, as well as to the ends of the oligonucleotide at low temperature. Studies of the Delta-cis-beta-[Ru(RR-picchxnMe(2))(phen)](2+) complex with [d(CGCGATCGCG)](2) showed that the complex binds only weakly to the ends of the oligonucleotide. The interaction of Delta-cis-alpha-[Ru(RR-picchxnMe(2))(dpq)](2+) with [d(CGCGATCGCG)](2) showed intermediate exchange kinetics and evidence of minor groove intercalation at the GA base step. In contrast to the phen and dpq complexes, Delta-cis-alpha- and Delta-cis-beta-[Ru(RR-picchxnMe(2))(phi)](2+) showed evidence of major groove binding independent of the metal ion configuration. DNA stabilization induced by complex binding to [d(CGCGATCGCG)](2) (measured as DeltaT(m)) increases in the order phen < dpq and DNA affinity in the order phen < dpq < phi. The groove binding preferences exhibited by the different bidentate ligands is explained with the aid of molecular modeling experiments.
Mass spectral compatibility of four proteomics stains
Publisher: American Chemical Society (ACS)
Date: 11-10-2007
DOI: 10.1021/PR070398Z
Abstract: With the recent introduction of new fluorescence stains to the proteomics market, there is now more choice available. SYPRO Ruby, LavaPurple, Flamingo, and Krypton total protein stains were compared for ease of use, image quality, and compatibility with protein identification by peptide mass fingerprinting (PMF) (MALDI-TOF). All four stains produced good images but with slightly different staining patterns. SYPRO was found to inhibit identification of cysteine and tryptophan containing peptides, which reduced protein identification.
Design and Synthesis of Epicocconone Analogues with Improved Fluorescence Properties
Publisher: American Chemical Society (ACS)
Date: 16-10-2014
DOI: 10.1021/JA506914P
Abstract: Epicocconone is a natural latent fluorophore that is widely used in biotechnology because of its large Stokes shift and lack of fluorescence in its unconjugated state. However, the low photostability and quantum yields of epicocconone have limited its wider use, and in the absence of a total synthesis, this limitation has been a long-standing problem. Here we report a general strategy for the synthesis of epicocconone analogues that relies on a 2-iodoxybenzoic acid-mediated dearomatization and on the replacement of the triene tail of the natural product by an aromatic ring. This design element is general and the synthesis is straightforward, providing ready access to libraries of polyfunctional fluorophores with long Stokes shifts based on the epicocconone core. Our structural modifications resulted in analogues with increased photostability and quantum yields compared with the natural product. Staining proteomic gels with these new analogues showed significant lowering of the detection limit and a 30% increase in the number of low-abundance proteins detected. These epiccoconone analogues will substantially improve the discovery rate of biomarker needles in the proteomic haystack.
Chlorinated metabolites from Streptomyces sp. highlight the role of biosynthetic mosaics and superclusters in the evolution of chemical diversity
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1OB00600B
Abstract: Biosynthetic mosaics and superclusters provide rare insights into the evolution of microbial chemical ersity.
New Antimicrobial Bromotyrosine Analogues from the Sponge Pseudoceratina purpurea and Its Predator Tylodina corticalis
Publisher: MDPI AG
Date: 16-03-2015
DOI: 10.3390/MD13031389
5-Chloropicolinic acid is produced by specific degradation of 4chlorobenzoic acid by Sphingomonas paucimobilis BPSI-3
Publisher: Oxford University Press (OUP)
Date: 10-1999
Abstract: We have previously shown that the bacterium Sphingomonas paucimobilis BPSI-3, isolated from PCB-contaminated soil, can degrade halogenated biphenyls, naphthalenes, catechols and benzoic acids. However, before such an organism can be used in bioremediation, it is important to characterise the degradation products and determine the degradation pathways to ensure that compounds more toxic or mobile than the original contaminants are not produced. In the degradation of 4-chlorobiphenyl, S. paucimobilis BPSI-3 produces a novel chlorinated picolinic acid. In this paper, we show that 4-chlorobenzoate is an intermediate in this degradation and, through (15)N-labelling, that 5-chloropicolinate is the only nitrogenous metabolite isolated under the extraction conditions used. The position of the chlorine indicates that degradation of 4-chlorocatechol occurs exclusively via a 2,3-extradiol cleavage. These data allow us to postulate a more definitive catabolic pathway for the biodegradation of 4-chlorobiphenyl to 5-chloro-2-hydroxymuconic acid semialdehyde via 4-chlorobenzoate in S. paucimobilis BPSI-3.
The Role of Different Structural Motifs in the Ultrafast Dynamics of Second Generation Protein Stains
Publisher: American Chemical Society (ACS)
Date: 20-11-2013
DOI: 10.1021/JP4092927
Abstract: Engineering the properties of fluorescent probes through modifications of the fluorophore structure has become a subject of interest in recent times. By doing this, the photophysical and photochemical properties of the modified fluorophore can be understood and this can guide the design and synthesis of better fluorophores for use in biotechnology. In this work, the electronic spectra and fluorescence decay kinetics of four analogues of the fluorescent natural product epicocconone were investigated. Epicocconone is unique in that the native state is weakly green fluorescent, whereas the enamine formed reversibly with proteins is highly emissive in the red. It was found that the ultrafast dynamics of the analogues depends profoundly on the H-bonding effect of solvents and solvent viscosity though solvent polarity also plays a role. Comparing the steady state and time-resolved data, the weak fluorescence of epicocconone in its native state is most likely due to the photoisomerization of the hydrocarbon side chain, while the keto enol moiety also has a role to play in determining the fluorescence quantum yield. This understanding is expected to aid the design of better protein stains from the same family.
Halopicolinic acids, novel products arising through the degradation of chloro- and bromobiphenyl by Sphingomonas paucimobilis BPSI-3
Publisher: Canadian Science Publishing
Date: 1996
DOI: 10.1139/M96-009
Abstract: Sphingomonas paucimobilis BPSI-3 was previously isolated from a mixed microbial consortium growing on biphenyl as the sole source of carbon and energy. Transformation of 4 -chlorobiphenyl (4CBP) was demonstrated by this strain, although little or no growth was observed. In minimal salts medium supplemented with 4CBP or bromobiphenyl and dextrose, yellow coloured product(s) were rapidly formed. Gas chromatography – mass spectrometry (GC–MS) revealed single ring N-heterocyclic compounds that were identified as halopicolinic acids. We believe this to be the first report of such compounds being formed via biological transformation of halobiphenyls. A mechanism is proposed for their formation.Key words: halobiphenyl degradation, halopicolinic acid, Sphingomonas paucimobilis BPSI-3, bioremediation.
Isolation and Structure Elucidation of Additional Alkaloids from the Tropical Rainforest Tree Galbulimima baccata
Publisher: American Chemical Society (ACS)
Date: 07-09-2021
DOI: 10.1021/ACS.JNATPROD.1C00537
Abstract: The structures of five new natural products (GB 27-GB 31,
Rapid screening of the antimicrobial activity of extracts and natural products
Publisher: Japan Antibiotics Research Association
Date: 1994
DOI: 10.7164/ANTIBIOTICS.47.1295
Abstract: A spectrophotometric method has been developed for the rapid measurement of the antimicrobial activity of natural products, including crude extracts or pure materials. The assay depends on the measurement of non-specific esterase activity using fluorescein diacetate (FDA) hydrolysis in broth cultures of microbes after they have been treated with test compounds. The assay is accurate, reproducible and economical in both time and materials. The speed and economy of the method make it suitable for the rapid screening of many s les and the bioassay directed purification of antimicrobial substances. The assay can also be used with a wide variety of micro-organisms since most micro-organisms are FDA positive. Applications are described in the fields of marine natural products chemistry and essential oils research.
Isolation and total synthesis of two novel metabolites from the fissurellid mollusc Scutus antipodes
Publisher: Elsevier BV
Date: 03-2017
Enantiodivergence in the Biosynthesis of Bromotyrosine Alkaloids from Sponges?
Publisher: American Chemical Society (ACS)
Date: 13-01-2017
DOI: 10.1021/ACS.JNATPROD.6B01038
Abstract: The isolation of bromotyrosine alkaloids, some of which are enantiomers of previously isolated compounds, has highlighted a possible enantio ergence in their biosynthesis. Two new (1, 2) and six known bromotyrosine alkaloids (4-9), and the enantiomer (10) of a known compound, have been isolated from a Western Australian marine sponge, Pseudoceratina cf. verrucosa. The compounds inhibited the growth of multidrug-resistant and methicillin-resistant Staphylococcus aureus with comparable activity to vancomycin. In addition, one possible artifact of extraction (3) containing an ethoxy group was isolated. From analysis of the known bromotyrosine alkaloids, a biogenesis is proposed that explains the formation of antipodal natural products within this family of sponges.
Recombinant Prespore‐Specific Antigen from Dictyostelium discoideum is a β‐sheet Glycoprotein with a Spacer Peptide Modified by O‐linked N‐acetylglucosamine
Publisher: Wiley
Date: 06-1996
DOI: 10.1111/J.1432-1033.1996.0511Z.X
Abstract: Prespore-specific antigen (PsA) is a putative cell-adhesion molecule of the cellular slime mould Dictyostelium discoideum, which has a similar molecular architecture to several mammalian cell-surface proteins. It has an N-terminal globular domain presented to the extracellular environment on an O-glycosylated stem (glycopeptide) that is attached to the cell membrane through a glycosyl-PtdIns anchor. The sequence of PsA suggests that PsA may belong to a new family of cell-surface molecules and here we present information on the structure of the N-terminal globular domain and determine the reducing-terminal linkage of the O-glycosylation. To obtain a sufficient amount of pure protein, a secreted recombinant form of PsA (rPsA), was expressed in D. discoideum and characterised. 1H-NMR spectra of rPsA contained features consistent with a high degree of beta-sheet in the N-terminal globular domain, a feature commonly observed in cell-adhesion proteins. Solid-phase Edman degradation of the glycopeptide of rPsA indicated that 14 of the 15 threonines and serines in the spacer region were glycosylated. The chemical structures of the O-glycosylations were determined to be single N-acetylglucosamine residues.
Solution structure and behaviour of Δ-m-α-[Ru(R,R- picchxnMe2)(phi)]2+ by NMR spectroscopy and molecular modelling
Publisher: Royal Society of Chemistry (RSC)
Date: 17-12-2003
DOI: 10.1039/B208846K
An efficient and concise method to synthesize locked GFP chromophore analogues
Publisher: Elsevier BV
Date: 11-2016
A one-pot synthesis and biological activity of ageladine A and analogues
Publisher: American Chemical Society (ACS)
Date: 17-03-2011
DOI: 10.1021/JM200039M
Abstract: A one-pot synthesis of ageladine A and analogues is reported. The key Pictet-Spengler reaction between 2-aminohistamine and aryl aldehydes has been successfully utilized for the synthesis of the natural product and 14 analogues. These compounds were screened for their matrix metalloprotease (MMP) and kinase inhibition to develop the first structure-activity relationship of ageladine A analogues. One compound, which showed significant kinase activity but little MMP inhibitory activity, was found to be highly active in an antiangiogenic screen, suggesting that the angiogenic activity of ageladine A is not associated with MMP inhibition but rather kinase inhibitory activity. Cytotoxicity was excluded as a mode of action by the assay of ageladine A and an analogue against 60 human cell lines.
Geometrical Frustration and Planar Triangular Antiferromagnetism in Quasi-Three-Dimensional Artificial Spin Architecture
Publisher: American Physical Society (APS)
Date: 30-12-2020
Hypervalent silicate-assisted azidation approach for the substituted azepane motif
Publisher: Elsevier BV
Date: 12-2022
Three-component mannich-like reaction of 2-aminoimidazole
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/CH11358
Abstract: A three-component reaction of 2-aminoimidazole with various aldehydes and amines is described that generates 4-substituted 2-aminoimidazoles containing a new chiral centre, a new C–C bond and a new C–N bond. The reactions can be conducted in water and require only sodium carbonate as reagent.
Is it time for artificial intelligence to predict the function of natural products based on 2D-structure
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9MD00128J
Abstract: One of chemistry's grand challenges is to find a function for every known metabolite. We explore the opportunity for artificial intelligence to provide rationale interrogation of metabolites to predict their function.
Talauxins: Hybrid Phenalenone Dimers from Talaromyces stipitatus
Publisher: American Chemical Society (ACS)
Date: 02-03-2020
Optimisation of the fluorescein diacetate antibacterial assay
Publisher: Elsevier BV
Date: 2005
DOI: 10.1016/J.MIMET.2004.08.010
Abstract: The fluorescein diacetate (FDA) antibacterial assay relies on the cleavage of fluorescein diacetate by metabolically active bacteria. The recent finding that microbiological media can lead to significant levels of cleavage has reduced the reliability of the assay. Using the nucleophilic scavengers N-ethylmaleimide and maleic anhydride, we have demonstrated that this abiotic cleavage is most likely due to nucleophiles such as cysteine and histidine commonly present in the media. To increase the reliability of the assay we have modified the original assay conditions to include use of dilute medium (peptone 0.2% w/v, yeast extract 0.1% w/v and NaCl 0.1% w/v) in a non-nucleophilic buffer and overnight incubation of the medium after addition of antibacterial agents. The optimised fluorescein diacetate assay has been used to determine the MIC of gentamicin, tetracycline and chlor henicol for Escherichia coli, Staphyloccocus aureus and Pseudomonas aeruginosa and gave quantitative results that were reproducible and consistent with published data.
Crellasterones A and B: A-Norsterol Derivatives from the New Caledonian Sponge Crella incrustans
Publisher: MDPI AG
Date: 15-06-2017
DOI: 10.3390/MD15060177
Abstract: Two new steroids, crellasterones A (1) and B (2), together with the previously reported compound chalinasterol (3) and several nucleosides (4–7), were isolated from the sponge Crella incrustans, collected in New Caledonia. The structures of the new compounds were established by extensive NMR and mass spectroscopic analysis and revealed unprecedented marine natural products with a ring-contracted A-norsterone nucleus and 2-hydroxycyclopentenone chromophore. The absolute configurations were derived from electronic circular dichroism (ECD) measurements in conjunction with high-level density functional theory (DFT) calculations.
Natural products from three nudibranchs: Nembrotha kubaryana, Hypselodorisinfucata and Chromodoris petechialis
Publisher: MDPI AG
Date: 31-01-2002
DOI: 10.3390/70100001-REV
ChemVoyage
Publisher: American Chemical Society (ACS)
Date: 19-04-2012
DOI: 10.1021/ED200533U
Rapid isolation of novel FK506 binding proteins from multiple organisms using gDNA and cDNA T7 phage display
Publisher: Elsevier BV
Date: 10-2009
DOI: 10.1016/J.BMC.2009.08.039
Abstract: Reverse chemical proteomics using T7 phage display is a powerful technique for identifying cellular receptors of biologically active small molecules. However, to date this method has generally been limited to cDNA libraries constructed from mRNA isolated from eukaryotes. In this paper, we describe the construction of the first prokaryotic T7 phage display libraries from randomly digested Pseudomonas stutzeri and Vibrio fischeri gDNA, as well as a plant cDNA library from Arabidopsis thaliana. We also describe the use of T7 phage display to identify novel proteins from environmental DNA s les using biotinylated FK506 as a model affinity probe.
Chemical ecology of the nudibranchs
Publisher: Springer Berlin Heidelberg
Date: 1987
Fluoroprofile, a fluorescence-based assay for rapid and sensitive quantitation of proteins in solution
Publisher: Wiley
Date: 12-2005
Abstract: The development of a sensitive fluorescence-based assay for the quantitative determination of protein concentration is described. The assay is based on the natural product epicocconone, which produces a large increase in fluorescence quantum yield upon binding to detergent-coated proteins in solution. There is a concomitant shift in the emission maximum from 520 to 605 nm after binding, which results in low background signal allowing a linear dynamic range of 40 ng/mL to 200 microg/mL for most proteins. There is little protein-to-protein variation except for iron-containing proteins and the assay can be used so that it is tolerant of chemicals commonly used in 2-D s le buffers. The assay is more sensitive than standard absorption assays such as the Bradford and Lowry assays, and has a greater dynamic range and sensitivity than other fluorescent assays.
Reverse Chemical Proteomics in Drug Discovery
Publisher: MDPI AG
Date: 2009
Sterol composition and classification of the Porifera
Publisher: Elsevier BV
Date: 1991
Characterisation of a novel UV filter in the lens of the thirteen-lined ground squirrel (Ictidomys tridecemlineatus)
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.EXER.2014.01.022
Abstract: Structural analysis of a novel UV filter present in the lens of the thirteen-lined ground squirrel has shown that it is related in structure to N-acetyl-3-hydroxykynurenine. This finding is consistent with the fact that the squirrel lenses also contain high levels of this tryptophan metabolite. Analysis of both NMR and mass spectrometric data suggested that the novel UV filter compound forms by condensation of proline with N-acetyl-3-hydroxykynurenine. Its absorption maximum at 340 nm is more than 20 nm lower than that of the kynurenines and it may therefore assist in filtering the more damaging shorter wavelengths of UVA.
Temporal Resolution of the Methylation Sequence of Vitamin B12 Biosynthesis
Publisher: American Chemical Society (ACS)
Date: 03-1989
DOI: 10.1021/JA00187A064
Politics and Trade Cooperation in the Nineteenth Century: The “Agreeable Customs” of 1815–1914. By Robert Pahre. New York: Cambridge University Press, 2008. 446p. $95.00.
Publisher: Cambridge University Press (CUP)
Date: 19-08-2009
Secondary metabolites from Basotho medicinal plants. I. Bulbine narcissifolia
Publisher: American Chemical Society (ACS)
Date: 10-2001
DOI: 10.1021/NP010279C
Abstract: The medicinal plant Bulbine narcissifolia is used by the Basotho, Griqua, and whites of southern Africa for wound healing and as a mild purgative. Extraction of the powdered root has yielded acetosyringone, chrysophanol, knipholone, isoknipholone, 10,7'-bichrysophanol, and chrysalodin in addition to two new anthraquinone glycosides, knipholone-8-O-beta-D-gentiobioside (1) and chrysalodin-10-beta-D-gentiobioside (2). NMR spectroscopy was used to elucidate the structures of 1 and 2 and to show that 1 binds weakly to DNA.
Bisindole alkaloids from a New Zealand deep-sea marine sponge Lamellomorpha strongylata
Publisher: MDPI AG
Date: 04-12-2019
DOI: 10.3390/MD17120683
Abstract: Chemical investigation of the secondary metabolites of a rare New Zealand deep-sea sponge, Lamellomorpha strongylata, resulted in the isolation of twenty-one indole alkaloids, including two new bisindoles—(Z)-coscinamide D (1), (E)-coscinamide D (2)—and four compounds isolated for the first time as natural products—lamellomorphamides A (3), B (4), C (5) and D (6). In addition, fifteen previously reported natural products were isolated, seven of which are seco analogs of hamacanthin alkaloids. The one sponge produces enantiomerically pure but opposite configurations of compounds that only differ in the number of bromines, suggesting enantio ergent biosynthesis. In addition, four compounds were isolated as partial racemates, suggesting these compounds are biosynthesized via two independent routes.
Rapid identification of a protein binding partner for the marine natural product kahalalide F by using reverse chemical proteomics
Publisher: Wiley
Date: 21-02-2008
Quantitation of the anticancer drug abiraterone and its metabolite Δ(4)-abiraterone in human plasma using high-resolution mass spectrometry
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.JPBA.2018.03.012
Abstract: Abiraterone acetate is administered as a prodrug to patients with metastatic, castration-resistant prostate cancer (mCRPC) and is readily metabolized into the potent 17a-hydroxylase/17,20-lyase (CYP17) enzyme inhibitor and androgen receptor inhibitor abiraterone and Δ(4)-abiraterone (D4A), respectively. To investigate pharmacokinetic variability in abiraterone acetate metabolism we developed highly sensitive liquid chromatography/mass spectrometry (LC/MS) assays for the simultaneous quantitation of abiraterone and D4A in human plasma using high-resolution mass spectrometry (HRMS) on an Orbitrap mass spectrometer. This study demonstrates the quantitative performance of HRMS and compares the conventional Parallel Reaction Monitoring (PRM) mode of quantitation with the unconventional Full scan MS mode conducted at high resolution (>70,000 resolution). The use of HRMS for quantitation of abiraterone and D4A yielded assays that were linear over a broad concentration range (0.074-509.6 ng/mL for abiraterone 0.075-59.93 ng/mL for D4A) in both Full scan MS and PRM modes. The assay precision for abiraterone and D4A was below 5% in PRM mode and 7% in Full scan MS mode. Accuracies fell within 98-107% for abiraterone and 104-112% for D4A in PRM mode, and 96-116% for abiraterone and 96-105% for D4A in Full scan MS mode, each meeting the acceptance criteria of FDA approved guidelines for bioanalytical methods The PRM analysis of abiraterone and D4A provided high specificity and reduced background interference, however the Full scan MS detection at a resolution of 70,000 was advantageous in that it required minimal optimization, was simple to implement, yielded comparable quantitative characteristics to PRM and the data is useful for re-analysis. Use of the assays were demonstrated for quantitation of these metabolites in steady state trough level plasma of seventeen (17) patients with mCRPC, demonstrating the inter-patient variability of up to 10-fold concentration.
Mass spectrometric compatibility of Deep Purple and SYPRO Ruby total protein stains for high-throughput proteomics using large-format two-dimensional gel electrophoresis
Publisher: Wiley
Date: 21-02-2008
DOI: 10.1002/RCM.3483
Abstract: In order to identify putative biomarkers from two-dimensional (2D) gel electrophoresis it is necessary to use a visualization technique that is sensitive, has a large dynamic range and does not interfere with the identification of the protein. As mass spectrometry increases in sensitivity more pressure is placed on visualization techniques that facilitate proteomic workflows but do not interfere with downstream processing. Two stains reported to meet these requirements are SYPRO Ruby (Invitrogen) and Deep Purple (GE Healthcare). This study examined the compatibility of these stains with protein identification by selecting spots from replicate 2D gels of human plasma and subjecting these to protein identification using liquid chromatography/tandem mass spectrometry (LC/MS/MS). Using a test of two populations of proportions it was found that proteins were statistically more likely to be identified from gels stained with Deep Purple. Additionally, the identifications from Deep Purple stained gels are of higher quality because they are based on multiple peptides.
Synthesis of a new hydrophilic o-nitrobenzyl photocleavable linker suitable for use in chemical proteomics
Publisher: Elsevier BV
Date: 11-2005
Epicocconone, a novel fluorescent compound from the fungus Epicoccum nigrum
Publisher: American Chemical Society (ACS)
Date: 11-07-2003
DOI: 10.1021/JA035496+
Abstract: Epicocconone represents a new class of natural fluorescent probes based on a polyketide skeleton isolated from the fungus Epicoccum nigrum. Epicocconone is a small, cell permeable natural product with a high molar absorbtivity and a long Stokes' shift that will be useful in biotechnological applications.
The constituents of marine sponges. I the isolation from aplysilla sulphurea (dendroceratida) of (1r*, 1′s*, 1″r*, 3r*)-1-acetoxy-4-ethyl-5-(1, 3, 3-trimethylcyclohexyl)-1, 3-dihydroisobenzofuran-l′(4), 3-carbolactone and the determination of its crystal structure
Publisher: CSIRO Publishing
Date: 1984
DOI: 10.1071/CH9841081
Abstract: Extraction of the sponge Aplysilla sulphurea (Order, Dendroceratida) yielded two crystalline substances, aplysulphurin, C22H28O5, and aplysulphuride, C22H32O5 Chemical and spectroscopic evidence suggested that aplysulphurin, the title compound, had the structure (2). This was confirmed by a single-crystal X-ray determination.
A fluorescent natural product for ultra sensitive detection of proteins in one-dimensional and two-dimensional gel electrophoresis
Publisher: Wiley
Date: 12-2003
Abstract: Lightning Fast is a sensitive fluorescence-based stain for detecting proteins in one-dimensional and two-dimensional polyacrylamide electrophoresis gels. It contains the fluorophore epicocconone from the fungus Epicoccum nigrum that interacts noncovalently with sodium dodecyl sulfate and protein. Stained proteins can be excited optimally by near-ultraviolet light of about 395 nm or with visible light of about 520 nm. The stain can be excited using a range of sources used in image analysis systems including UVA (ca. 365 nm) and UVB (ca. 302 nm) transilluminators Xenon-arc l s 488 nm and 457 nm Argon-ion lasers 473 nm and 532 nm neodymium: yttrium aluminum garnet (Nd:YAG) solid-state lasers 543 nm helium-neon lasers, and emerging violet, blue and green diode lasers. Maximum fluorescence emission of the dye is at approximately 610 nm. The limit of detection in one-dimensional gels stained with Lightning Fast protein gel stain is less than 100 pg of protein, rivaling the current limits of matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). Lightning Fast was found to be considerably more sensitive than SYPRO Ruby, SYPRO Orange, silver and Coomassie Brilliant Blue G-250 in matched experiments. Staining takes as little as 3.5 h and stained proteins displayed quantitative linearity over more than four orders of magnitude, thereby allowing visualization of entire proteomes. Lightning Fast protein gel staining is compatible with subsequent peptide mass fingerprinting using MALDI-MS and Edman-based sequencing chemistry.
Synthesis of Substituted Oxo-Azepines by regioand diastereoselective Hydroxylation
Publisher: MDPI AG
Date: 31-10-2017
Concise total synthesis of the marine natural product ageladine A
Publisher: American Chemical Society (ACS)
Date: 08-2006
DOI: 10.1021/OL061584Y
Abstract: A total synthesis of ageladine A has been achieved by exploiting a Pictet-Spengler-type condensation between 2-aminohistamine and 4,5-dibromo-2-formylpyrrole as the key step.
Novel secoiridoids with antioxidant activity from Australian olive mill waste
Publisher: American Chemical Society (ACS)
Date: 21-03-2007
DOI: 10.1021/JF063300U
Abstract: A new biophenolic secoiridoid was identified in Australian Frantoio olive mill waste (OMW) extracts. Isolation, purification, and structure elucidation were performed. Hydroxytyrosyl acyclodihydroelenolate, the first nonaldehydic acyclic secoiridoid, is reported. A second compound was identified as p-coumaroyl-6'-secologanoside (comselogoside), and although it has been identified recently in OMW and leaves, this is the first time it has been identified in both OMW and olive fruits. UV, mass spectral, and NMR data are given for both compounds. The two compounds were quantified by HPLC-DAD, and their antioxidant potential was assessed against the classical olive biophenols, hydroxytyrosol and oleuropein, by the in vitro DPPH radical scavenging assay.
Epicocconone, a new cell-permeable long stokes' shift fluorescent stain for live cell imaging and multiplexing
Publisher: Springer Science and Business Media LLC
Date: 03-12-2006
DOI: 10.1007/S10895-005-0010-7
Abstract: Epicocconone is a heterocyclic natural product from the fungus Epicoccum nigrum that fluoresces weakly in the green (520 nm). However, cells exposed to epicocconone rapidly absorb the dye and become bright orange fluorescent because the natural product reacts reversibly with proteins. The orange fluorescence is enhanced in lipophilic environments, allowing the visualization of membranous organelles and lipid rafts but does not stain oligonucleotides. As the unconjugated dye has no orange fluorescence, there is no need to wash out the excess fluorophore. Epicocconone is a neutral, non-toxic, small molecule that appears to diffuse readily into live of fixed cells without the need for permeabilization. These features enable the real-time imaging of live cells and the study of organelle movements. Cells stained with epicocconone are excitable by common lasers (UV, 405, 488, and 532 nm) and its long Stokes' shift allows multiplexing applications with more common short Stokes' fluorophores using a single light source.
Reverse chemical proteomics identifies an unanticipated human target of the antimalarial artesunate
Publisher: American Chemical Society (ACS)
Date: 06-03-2019
DOI: 10.1021/ACSCHEMBIO.8B01004
Abstract: Artemisinins are the most potent and safe antimalarials available. Despite their clinical potential, no human target for the artemisinins is known. The unbiased interrogation of several human cDNA libraries, displayed on bacteriophage T7, revealed a single human target of artesunate the intrinsically disordered Bcl-2 antagonist of cell death promoter (BAD). We show that artesunate inhibits the phosphorylation of BAD, thereby promoting the formation of the proapoptotic BAD/Bcl-xL complex and the subsequent intrinsic apoptotic cascade involving cytochrome c release, PARP cleavage, caspase activation, and ultimately cell death. This unanticipated role of BAD as a possible drug target of artesunate points to direct clinical exploitation of artemisinins in the Bcl-xL life/death switch and that artesunate's anticancer activity is, at least in part, independent of reactive oxygen species.
Natural products from sponges of the genus Agelas - On the trail of a [2+2]-photoaddition enzyme
Publisher: MDPI AG
Date: 16-01-2001
DOI: 10.3390/60100130
Site-Directed Mutagenesis and High-Resolution NMR Spectroscopy of the Active Site of Porphobilinogen Deaminase
Publisher: American Chemical Society (ACS)
Date: 18-10-1988
DOI: 10.1021/BI00421A002
Abstract: The active site of porphobilinogen (PBG)1 deaminase (EC 4.3.1.8) from Escherichia coli has been found to contain an unusual dipyrromethane derived from four molecules of 5-aminolevulinic acid (ALA) covalently linked to Cys-224, one of the two cysteine residues conserved in E. coli and human deaminase. By use of a hemA- strain of E. coli the enzyme was enriched from [5-13C]ALA and examined by 1H-detected multiple quantum coherence spectroscopy, which revealed all of the salient features of a dipyrromethane composed of two PBG units linked head to tail and terminating in a CH2-S bond to a cysteine residue. Site-specific mutagenesis of Cys-99 and Cys-242, respectively, has shown that substitution of Ser for Cys-99 does not affect the enzymatic activity, whereas substitution of Ser for Cys-242 removes essentially all of the catalytic activity as measured by the conversion of the substrate PBG to uro'gen I. The NMR spectrum of the covalent complex of deaminase with the suicide inhibitor 2-bromo-[2,11-13C2]PBG reveals that the aninomethyl terminus of the inhibitor reacts with the enzyme's cofactor at the alpha-free pyrrole. NMR spectroscopy of the ES2 complex confirmed a PBG-derived head-to-tail dipyrromethane attached to the alpha-free pyrrole position of the enzyme. A mechanistic rationale for deaminase is presented.
Banksialactones and Banksiamarins: Isochromanones and Isocoumarins from an Australian Fungus, Aspergillus banksianus
Publisher: American Chemical Society (ACS)
Date: 19-06-2018
DOI: 10.1021/ACS.JNATPROD.7B00816
Abstract: Chemical investigation of an Australian fungus, Aspergillus banksianus, led to the isolation of the major metabolite banksialactone A (1), eight new isochromanones, banksialactones B-I (2-9), two new isocoumarins, banksiamarins A and B (10 and 11), and the reported compounds, clearanol I (12), dothideomynone A (13), questin (14), and endocrocin (15). The structures of 1-11 were established by NMR spectroscopic data analysis, and the absolute configurations were determined from optical rotations and ECD spectra in conjunction with TD-DFT calculations. The secondary metabolite profile of A. banksianus is unusual, with the 11 most abundant metabolites belonging to a single isochromanone class. Conjugation of 1 with endocrocin, 5-methylorsellinic acid, 3,5-dimethylorsellinic acid, mercaptolactic acid, and an unknown methylthio source gave rise to five unprecedented biosynthetic hybrids, 5-9. The isolated compounds were tested for cytotoxicity, antibacterial, and antifungal activities, with hybrid metabolites 7-9 displaying weak cytotoxic and antibiotic activities.
Conformational Analysis of the cis‐ and trans‐Isomers of FK506 by NMR and Molecular Dynamics
Publisher: Wiley
Date: 07-08-1991
Epicocconone–Hemicyanine Hybrids: Near Infrared Fluorophores for Protein Staining and Cell Imaging
Publisher: Wiley
Date: 15-12-2016
Abstract: The development of new near infrared (NIR) dyes is crucial for erse applications and especially bioimaging, as they absorb and emit light in the "therapeutic window" (650-950 nm). We report here a new family of NIR fluorophores that has been obtained by hybridising hemicyanines with epicocconone. Emission wavelengths of these hybrid dyes is in the range 715-795 nm and is combined with large Stokes' shifts (75-95 nm). The absorption and emission wavelength can be modulated according to the hemicyanine moiety and adding sulfonic acid moieties enhances water solubility. We demonstrate their application in the sensitive detection of proteins in gel electrophoresis and the staining of specific cellular organelles in confocal microscopy. These results are particularly encouraging and bring forward a new fluorescent skeleton for chemical biology.
Real-time fluorescence monitoring of tryptic digestion in proteomics
Publisher: American Chemical Society (ACS)
Date: 12-2008
DOI: 10.1021/PR0704480
Abstract: Ensuring that proteolytic digestions are complete before submitting s les for downstream proteomic analyses is important, as failure or partial digestion can waste valuable instrument time and make results difficult to interpret. Conversely, overdigestion can also be problematic, such as when removing affinity tags from recombinant proteins or using nonspecific proteases. The techniques of HPLC, circular dichroism, SDS-PAGE, and MS have each been used to assess protein digestion. These techniques are slow, may require expensive instrumentation, can be inaccurate, and/or are unsuitable for real-time monitoring. Epicocconone is a natural fluorophore that reacts reversibly with proteins to form a highly fluorescent adduct and has previously been used to quantify proteins in 1D and 2D gels and in solution. Here, we describe a new method for the real-time monitoring of protein digestion based on epicocconone. This unique in situ fluorescent assay can tracelessly follow proteolysis of s les, at low microgram levels, destined for proteomics analysis or purification.
Structure determination of aplyviolene from Chelonaplysilla violacea
Publisher: International Union of Crystallography (IUCr)
Date: 15-12-1986
Natural Products in Polyclad Flatworms
Publisher: MDPI AG
Date: 21-01-2021
DOI: 10.3390/MD19020047
Abstract: Marine invertebrates are promising sources of novel bioactive secondary metabolites, and organisms like sponges, ascidians and nudibranchs are characterised by possessing potent defensive chemicals. Animals that possess chemical defences often advertise this fact with aposematic colouration that potential predators learn to avoid. One seemingly defenceless group that can present bright colouration patterns are flatworms of the order Polycladida. Although members of this group have typically been overlooked due to their solitary and benthic nature, recent studies have isolated the neurotoxin tetrodotoxin from these mesopredators. This review considers the potential of polyclads as potential sources of natural products and reviews what is known of the activity of the molecules found in these animals. Considering the ecology and ersity of polyclads, only a small number of species from both suborders of Polycladida, Acotylea and Cotylea have been investigated for natural products. As such, confirming assumptions as to which species are in any sense toxic or if the compounds they use are biosynthesised, accumulated from food or the product of symbiotic bacteria is difficult. However, further research into the group is suggested as these animals often display aposematic colouration and are known to prey on invertebrates rich in bioactive secondary metabolites.
Fluorometric assay for the determination of glutathione reductase activity
Publisher: American Chemical Society (ACS)
Date: 09-10-2007
DOI: 10.1021/AC071518P
Abstract: The determination of free sulfhydryl groups is important in many aspects of biotechnology, such as measuring the coupling efficiency of thiol-reactive probes, assaying cysteine-containing haptens, and assaying reductase/thiol transferase activity, as well as in various aspects of the food industry. This is generally achieved colorimetrically using Ellman's reagent, although the assay is relatively insensitive and Ellman's reagent is unstable. In this paper, we describe a highly sensitive fluorometric assay for free sulfhydryl groups based on FRET, which we have used to develop a sensitive assay for glutathione reductase activity. The assay exploits the specific increase in fluorescence intensity that occurs at 520 nm when a probe containing two molecules of fluorescein linked via a disulfide group is cleaved by glutathione. The assay is 2 orders of magnitude more sensitive than the commonly used colorimetric glutathione reductase assay and has a greater dynamic range.
Tracking of fast moving neuronal vesicles with ageladine A
Publisher: Elsevier BV
Date: 11-2010
DOI: 10.1016/J.BBRC.2010.10.055
Abstract: Ageladine A is a marine natural product that can be used to fluorescently stain living tissues and cells. Its fluorescence is highly pH dependent with the highest intensities under acidic conditions. We have used ageladine A to stain acidic vesicles in cells and found the compound especially useful for tracking transport vesicles in cultured nerve cells. Inward as well as outward ionic currents appear not to be influenced by ageladine A at concentrations of 10 μM or less. Higher concentrations than 30 μM reduce whole cell voltage dependent outward currents whereas inward currents remain unchanged up to 100 μM ageladine A (PC12 cells). Incubation with ageladine A (10 μM) in cultured hippoc al neurons does not alter miniature excitatory postsynaptic currents (mEPCS) litudes, frequency, rise or decay times. Fast moving vesicles are stained the brightest, suggesting they are the most acidic and likely to be Golgi derived and endocytotic vesicles for the fast anterograde and retrograde transport of proteins and other compounds needing an acidic environment.
Diastereoselective Pictet--Spengler Reactions of a Tethered 2-Aminoimidazole
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/CH13346
Abstract: The diastereoselective Pictet–Spengler reaction of aminopropyl-2-aminoimidazole with enantiopure aldehydes has been investigated. With amino acid-derived aldehydes, anti stereochemistry is favoured, with a diastereoselectivity up to 92 % achievable. The absolute stereochemistry of the products was determined through synthesis of a rigid derivative and from NMR data in combination with molecular modelling. The diastereoselectivity was shown to be dependent on the steric bulk of the amino acid side chain and independent of the nitrogen protecting group. Lewis acids catalysed the reaction but did not affect the diastereoselectivity.
9-hydroxyfurodysinin-O-ethyl lactone: A new sesquiterpene isolated from the tropical marine sponge dysidea arenaria
Publisher: MDPI AG
Date: 31-10-2005
DOI: 10.3390/10101292
Expanding antibiotic chemical space around the nidulin pharmacophore
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8OB00545A
Abstract: Reinvestigating antibiotic scaffolds that were identified during the Golden Age of antibiotic discovery, but have long since been “forgotten”, has proven to be an effective strategy for delivering next-generation antibiotics capable of combatting multidrug-resistant superbugs.
The constituents of marine sponges. VI. diterpenoid metabolites of the New Zealand sponge chelonaplysilla violacea
Publisher: CSIRO Publishing
Date: 1993
DOI: 10.1071/CH9930623
Abstract: The sponge Chelonaplysilla violacea, collected from New Zealand coastal waters, contains as major constituents the diterpenoids aplyviolene (1a), norrisolide (2), dendrillolide A (3) aplyroseol-7 (4), spongian-16-one (5), chelonaplysin C (6), and a series of new compounds cheloviolene A-F and cheloviolin. Structures were assigned to cheloviolene A (7), [3aR-[3aα,4α(1R*,3aR*,8aS*),5β,6aα]]-5-hydroxy-4(1,4,4-trimethyl-8-methylenedecahydroazulen-1-yl) tetrahydrofuro [2,3- b] furan-2(3H)-one, cheloviolene B (8), [3aR-[3aα,4a(1R*,3aR*, 8aS*),5α,6aα]]-5-hydroxy-4-(1,4,4-trimethyl-8-methylenedecahydroazulen-1-yl) tetrahydrofuro [2,3-b]furan-2(3H)-one, cheloviolene C (9), [1'ξ(1R*,3aS*,7aS*),4ξ]-4-[1′-( acetyloxymethyl )-2′-(4,4,7a-trimethyloctahydro-1H-inden-1-yl)prop-2′-enyl] dihydrofuran -2(3H)-one, cheloviolene D (10), methyl [3α,4α(1R*,3aR*,8aS*)]-5-oxo-4-(1,4,4-trimethyl-8-methylenedecahydroazulen-1-yl)tetrahydrofuran-3-acetate, cheloviolene E (11), methyl [3α,4α-(1R*,3aS*,7aS*)]-5-oxo-4-[1′-(4,4,7a-trimethyloctahydro-1H-inden-1-yl) ethenyl ]tetrahydrofuran-3-acetate, and cheloviolene F (12), [4ξ,5ξ(1R*,3R*,8aS*)]-4-( acetyloxymethyl )-5-(1,4,4-trimethyl-8-methylenedecahydroazulen-1-yl) tetrahydro-2H-pyran-2-one, by using spectroscopic methods the structure (13) was deduced for cheloviolin, [1S-[1α,5α,6α,8R*(1aS*,3aS*,7aS*,7b-R*)]]-6-acetyloxy-8-(4,4,7a-trimethyldecahydrocylopropa[a] naphthalen-la-yl )-2,7-dioxabicyclo- [3.2.1]octan-3-one.
A gloverin-like antibacterial protein is synthesized in Helicoverpa armigera following bacterial challenge
Publisher: Elsevier BV
Date: 07-1998
DOI: 10.1016/S0145-305X(98)00025-1
Abstract: A bacteria inducible antibacterial protein, P2, was isolated from the old world bollworm Helicoverpa armigera. Fifth-instar larvae were injected with live Escherichia coli NCTC 8196. P2 was isolated by HPLC using reversed-phase and size-exclusion columns. In addition, P2 was isolated by an alternative method of sequential cation-exchange and reversed-phase HPLC. The structure of P2 was determined by N-terminal Edman degradation and mass spectrometry. P2 had similar mass (14.1 kDa) structure and activity to gloverin, an inducible glycine-rich antibacterial protein isolated from Hyalophora gloveri [Axén, A. Carlsson, A. Engström, A. Bennich, H. Eur. J. Biochem. 247:614-619 1997]. At the N-terminus P2 had approximately 60% identity with gloverin. P2 is basic, heat stable, and displayed rapid antibacterial action. P2 was active against the Gram-negative bacteria tested and was inactive against the Gram-positive bacteria, Candida albicans, a bovine turbinate cell line, and pestivirus.
Formation of pigment precursor (+)-1″-methylene-6″-hydroxy2H- furan-5″-one-catechin isomers from (+)-catechin and a degradation product of ascorbic acid in a model wine system
Publisher: American Chemical Society (ACS)
Date: 28-10-2009
DOI: 10.1021/JF902198E
Abstract: The present study investigates the contribution of ascorbic acid to the formation of pigment precursors in model white wine systems containing (+)-catechin as the oxidizable phenolic substrate. The two main colorless products in these systems were structurally characterized as isomers of (+)-catechin substituted at either C6 or C8 on the A ring with a furan-type unit, namely, (+)-1''-methylene-6''-hydroxy-2H-furan-5''-one-6-catechin and (+)-1''-methylene-6''-hydroxy-2H-furan-5''-one-8-catechin. A known degradation product of ascorbic acid, L-xylosone, was separately prepared and, when reacted with (+)-catechin, generated the same (+)-furanone-catechin isomers as in model white wine systems. Incubation of these isomers in wine-like conditions yielded yellow xanthylium cation pigments. This study has shown that undesirable spoilage reactions (yellow coloration) can occur from a breakdown product of ascorbic acid-L-xylosone.
Biosynthetic Studies of Marine Lipids. 20.1 Sequence of Double-bond Introduction in the Sponge Sterol 24β-methylcholesta-5,7,22,25-tetraen-3β-ol
Publisher: American Chemical Society (ACS)
Date: 03-1989
DOI: 10.1021/JO00268A027
Synthesis of new BINAP-based aminophosphines and their 31P-NMR spectroscopy
Publisher: MDPI AG
Date: 03-2013
Investigation of a Coenzyme B12 Model Reaction by 13C NMR Spectroscopy
Publisher: American Chemical Society (ACS)
Date: 1994
DOI: 10.1021/JA00081A052
Chemistry of sponges, II. Pallescensone, a furanosesquiterpenoid from dictyodendrilla cavernosa
Publisher: American Chemical Society (ACS)
Date: 09-1987
DOI: 10.1021/NP50053A033
Peter Karuso and Paul J. Scheuer†, Natural Products from Three Nudibranchs: Nembrotha kubaryana, Hypselodoris infucata and Chromodoris petechialis, Molecules, 2002, 7, 1-6
Publisher: MDPI AG
Date: 31-01-2003
DOI: 10.3390/80800607
Abstract: n/a
2004 RACI one-day natural products group symposium
Publisher: MDPI AG
Date: 31-10-2005
DOI: 10.3390/10101229
Rechoreographing enterocin's ballet of isomers
Publisher: American Chemical Society (ACS)
Date: 07-12-2020
Consequences of Transferring Three Sorghum Genes for Secondary Metabolite (Cyanogenic Glucoside) Biosynthesis to Grapevine Hairy Roots
Publisher: Springer Science and Business Media LLC
Date: 04-2006
DOI: 10.1007/S11248-005-3737-7
Abstract: A multigenic trait (biosynthesis of the secondary metabolite, dhurrin cyanogenic glucoside) was engineered de novo in grapevine (Vitis vinifera L.). This follows a recent report of transfer of the same trait to Arabidopsis (Arabidopsis thaliana) using three genetic sequences from sorghum (Sorghum bicolor): two cytochrome P450-encoding cDNAs (CYP79A1 and CYP71E1) and a UDPG-glucosyltransferase-encoding cDNA (sbHMNGT). Here we describe the two-step process involving whole plant transformation followed by hairy root transformation, which was used to transfer the same three sorghum sequences to grapevine. Transgenic grapevine hairy root lines that accumulated transcript from none, one (sbHMNGT), two (CYP79A1 and CYP71E1) or all three transgenes were recovered and characterisation of these lines provided information about the requirements for dhurrin biosynthesis in grapevine. Only lines that accumulated transcripts from all three transgenes had significantly elevated cyanide potential (up to the equivalent of about 100 mg HCN kg(-1) fresh weight), and levels were highly variable. One dhurrin-positive line was tested and found to release cyanide upon maceration and can therefore be considered 'cyanogenic'. In in vitro dual co-culture of this cyanogenic hairy root line or an acyanogenic line with the specialist root-sucking, gall-forming, aphid-like insect, grapevine phylloxera (Daktulosphaira vitifoliae, Fitch), there was no evidence for protection of the cyanogenic plant tissue from infestation by the insect. Consistently high levels of dhurrin accumulation may be required for this to occur. The possibility that endogenous grapevine gene expression is modulated in response to engineered dhurrin biosynthesis was investigated using microarray analysis of 1225 grapevine ESTs, but differences in patterns of gene expression associated with dhurrin-positive and dhurrin-negative phenotypes were not identified.
Ultrafast dynamics of epicocconone, a second generation fluorescent protein stain
Publisher: American Chemical Society (ACS)
Date: 23-08-2011
DOI: 10.1021/JP205634G
Abstract: Femtosecond upconversion experiment has been carried out for epicocconone and its butylamine adduct in acetonitrile and tert-butanol. An ultrafast component is found to dominate the decay of fluorescence of epicocconone in acetonitrile solution. Upon reacting with butylamine, a model for the epicocconone-protein adduct, this ultrafast component remains almost unaffected but an additional rise time occurs, indicating the formation of a highly emissive species from the locally excited state. This phenomenon is central to the extraordinary applications of epicocconone in biotechnology. The magnitude of the rise time of the butylamine adduct is similar to that of the longer component of the decay of epicocconone in acetonitrile, suggesting that the dynamics of epicocconone and its butylamine adduct are similar. The ultrafast component is slowed upon increasing the viscosity of the solvent. This results in a marked increase in quantum yield and suggests that it corresponds to rapid bond isomerization, leading to a nonradiative decay. Surprisingly, in water/sucrose mixtures, the ultrafast component remains unaffected but there is still an increase in quantum yield, suggesting that there are at least two nonradiative pathways, one involving bond isomerization and another involving proton transfer. The correct interpretation of these data will allow the design of second generation protein stains based on the epicocconone scaffold with increased quantum yields and photostability.
Back Cover: Epicocconone–Hemicyanine Hybrids: Near Infrared Fluorophores for Protein Staining and Cell Imaging (Chem. Eur. J. 8/2017)
Publisher: Wiley
Date: 13-12-2017
Structure of tetrahydroaplysulfurin-1
Publisher: International Union of Crystallography (IUCr)
Date: 15-12-1987
Terpenoid constituents of morphologically similar sponges in the family aplysillidae
Publisher: CSIRO Publishing
Date: 1985
DOI: 10.1071/CH9861643
Abstract: The sponge Darwinella sp, contains the known compounds ambliofuran (4) and aplysulphurin (3), and the new compound tetrahydroaplysulphurin-1 (5). Darwinella oxeata collected from various locations around New Zealand, contains aplysulphurin (3) and the new compounds tetrahydroaplysulphurins-1 (5), -2 (6), and -3 (7). Dendrilla rosea which is morphologically similar to the Darwinella sp. above, contains the known compounds ambliofuran (4), aplyroseols-1 (8),-2 (9),-3 (10),-5(11),-6 (12), and -7(15), as well as the new compounds dendrillol-1 (13), dendrillol-2 (14), dendrillol-3 (17) and dendrillol-4 (18). The structure of dendrillol-1 (13) has been confirmed by a single-crystal X-ray determination.
Identifying the cellular targets of natural products using T7 phage display
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5NP00128E
Abstract: A description of the T7 phage biopanning procedure is provided with tips and advice suitable for setup in a chemistry laboratory.
Fluorescence anisotropy assay for the traceless kinetic analysis of protein digestion
Publisher: American Chemical Society (ACS)
Date: 24-04-2008
DOI: 10.1021/AC7025783
Abstract: A novel fluorescence polarization assay based on the natural fluorophore epicocconone has been developed. This assay allows the rapid and accurate determination of enzyme kinetic parameters as well as inhibition constants through the measurement of fluorescence anisotropy on the actual substrate of the protease. It takes advantage of epicocconone's ability to reversibly react with proteins to form an internal charge-transfer complex that is highly fluorescent. The protein-substrate is labeled in situ without the need for prior incubation and/or derivatization steps, which saves time and effort compared to methods employing specifically labeled protein-substrates. The assay can be carried out in 96- or 384-well plates, making it suitable for high-throughput applications in drug development and biotechnology.
Secondary Metabolites from Basotho Medicinal Plants. II Bulbine capitata
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/CH01126
Stability Analysis and Experimental Evaluation of a Control Strategy for Islanded Operation of Distributed Generation Units
Publisher: Institute of Electrical Engineers of Japan (IEE Japan)
Date: 2011
Related Organisations
Witten Institute For Family Business (WIFU), University Of Witten/Herdecke
Location: Germany
Macquarie University Faculty Of Science And Engineering
Location: Australia
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