ORCID Profile
0000-0001-8987-7092
Current Organisation
Tianjin University
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Publisher: Elsevier
Date: 2010
Publisher: Elsevier BV
Date: 09-2021
Publisher: American Chemical Society (ACS)
Date: 06-11-2014
DOI: 10.1021/JF502187C
Abstract: Thirty-six anthurium varieties, s led from species and commercial cultivars, were extracted and profiled by liquid-chromatography-mass spectrometry (HPLC-MS). Three hundred fifteen compounds, including anthocyanins, flavonoid glycosides, and other phenolics, were detected from these extracts and used in chemotaxonomic analysis of the specimens. Hierarchical cluster analysis (HCA) revealed close chemical similarities between all the commercial standard cultivars, while tulip-shaped cultivars and species displayed much greater chemical variation. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) supported the results from HCA and were used to identify key metabolites characteristic of standard and tulip cultivars and to identify chemical markers indicative of a particular ancestry. Discriminating metabolites included embinin, 4, which was characteristic of standard-shaped spathes and indicated ancestry from Anthurium andraeanum, while isocytisoside 7-glucoside, 7, was found in the majority of tulip-shaped cultivars and suggested that Anthurium amnicola or Anthurium antioquiense had contributed to their pedigree.
Publisher: Elsevier BV
Date: 05-2021
Publisher: American Chemical Society (ACS)
Date: 19-01-2006
DOI: 10.1021/OL052880Y
Abstract: [structure: see text] An Australian isolate of the soil ascomycete Gymnoascus reessii yielded a series of cytotoxic metabolites, including the known polyenylpyrroles rumbrin (1) and auxarconjugatin A (2), and the new rumbrin stereoisomer 12E-isorumbrin (3), as well as an unprecedented class of polyenylfurans exemplified by gymnoconjugatins A (4) and B (5). Structures were assigned with detailed spectroscopic analysis.
Publisher: American Chemical Society (ACS)
Date: 13-10-2020
Publisher: American Chemical Society (ACS)
Date: 30-06-2020
Publisher: Elsevier BV
Date: 05-2021
Publisher: Springer Science and Business Media LLC
Date: 24-07-2009
DOI: 10.1007/S00253-009-2127-0
Abstract: Incorporation of fluorine into an organic compound can favourably alter its physicochemical properties with respect to biological activity, stability and lipophilicity. Accordingly, this element is found in many pharmaceutical and industrial chemicals. Organofluorine compounds are accepted as substrates by many enzymes, and the interactions of microorganisms with these compounds are of relevance to the environment and the fine chemicals industry. On the one hand, the microbial transformation of organofluorines can lead to the generation of toxic compounds that are of environmental concern, yet similar biotransformations can yield difficult-to-synthesise products and intermediates, in particular derivatives of biologically active secondary metabolites. In this paper, we review the historical and recent developments of organofluorine biotransformation in microorganisms and highlight the possibility of using microbes as models of fluorinated drug metabolism in mammals.
Publisher: MDPI AG
Date: 06-06-2019
DOI: 10.3390/MD17060339
Abstract: This review outlines the research that was carried out regarding the isolation of bioactive compounds from marine-derived bacteria and fungi by China-based research groups from 2009–2018, with 897 publications being surveyed. Endophytic organisms featured heavily, with endophytes from mangroves, marine invertebrates, and marine algae making up more than 60% of the microbial strains investigated. There was also a strong focus on fungi as a source of active compounds, with 80% of publications focusing on this area. The rapid increase in the number of publications in the field is perhaps most notable, which have increased more than sevenfold over the past decade, and suggests that China-based researchers will play a major role in marine microbial natural products drug discovery in years to come.
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B600960C
Abstract: Detailed chemical analysis of the solid phase fermentation of an Australian Penicillium citrinum isolate has returned the known compounds citrinin (1), phenol A acid (6), dihydrocitrinone (7) and dihydrocitrinin (8), together with a novel cytotoxic dimer, dicitrinin A (5). Dicitrinin A (5) was determined to be a dimerised artefact of the major co-metabolite citrinin, and its structure solved by spectroscopic analysis and chemical modification. Analysis of the products encountered during the controlled decomposition of citrinin led to the discovery of additional citrinin dimers and delineated a plausible mechanistic pathway linking all monomeric and dimeric citrinin degradation products.
Publisher: MDPI AG
Date: 18-11-2022
DOI: 10.3390/ANTIBIOTICS11111655
Abstract: The emergence of drug resistant microbes over recent decades represents one of the greatest threats to human health the resilience of many of these organisms can be attributed to their ability to produce biofilms. Natural products have played a crucial role in drug discovery, with microbial natural products in particular proving a rich and erse source of antimicrobial agents. During antimicrobial activity screening, the strain Pseudomonas mosselii P33 was found to inhibit the growth of multiple pathogens. Following chemical investigation of this strain, pseudopyronines A-C were isolated as the main active principles, with all three pseudopyronines showing outstanding activity against Staphylococcus aureus. The analogue pseudopyronine C, which has not been well-characterized previously, displayed sub-micromolar activity against S. aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. Moreover, the inhibitory abilities of the pseudopyronines against the biofilms of S. aureus were further studied. The results indicated all three pseudopyronines could directly reduce the growth of biofilm in both adhesion stage and maturation stage, displaying significant activity at micromolar concentrations.
Publisher: American Chemical Society (ACS)
Date: 09-2004
DOI: 10.1021/NP049826V
Abstract: Chemical analysis of an Australian Streptomyces species yielded a range of known anthracyclines and biosynthetically related metabolites, including daunomycin (1), epsilon-rhodomycinone (2), 11-hydroxyauramycinone (3), 11-hydroxysulfurmycinone (4), aklavinone (5), bisanhydro-gamma-rhodomycinone (6), and the anthraquinone 7, as well as the hitherto unreported blanchaquinone (8). The structure assigned to 8 was secured by detailed spectroscopic analysis and correlation to known analogues, such as the anthraquinone 7. This account also represents the first natural occurrence of 3, 4, and 7 and the first spectroscopic characterization of 11-hydroxysulfurmycinone (4).
Publisher: MDPI AG
Date: 02-12-2020
DOI: 10.3390/MOLECULES25235689
Abstract: The alkyl-4-quinolones (AQs) are a class of metabolites produced primarily by members of the Pseudomonas and Burkholderia genera, consisting of a 4-quinolone core substituted by a range of pendant groups, most commonly at the C-2 position. The history of this class of compounds dates back to the 1940s, when a range of alkylquinolones with notable antibiotic properties were first isolated from Pseudomonas aeruginosa. More recently, it was discovered that an alkylquinolone derivative, the Pseudomonas Quinolone Signal (PQS) plays a key role in bacterial communication and quorum sensing in Pseudomonas aeruginosa. Many of the best-studied ex les contain simple hydrocarbon side-chains, but more recent studies have revealed a wide range of structurally erse ex les from multiple bacterial genera, including those with aromatic, isoprenoid, or sulfur-containing side-chains. In addition to their well-known antimicrobial properties, alkylquinolones have been reported with antimalarial, antifungal, antialgal, and antioxidant properties. Here we review the structural ersity and biological activity of these intriguing metabolites.
Publisher: Springer Science and Business Media LLC
Date: 11-08-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B813236D
Abstract: The biosynthesis of the pyrrolylpolyene rumbrin (1) in the fungus Auxarthron umbrinum was elucidated using feeding studies with labelled precursors. Incorporation of stable isotopes from [(15)N]-proline, [(13)C]-methionine and [(13)C]-acetate confirmed that these were the precursors of the pyrrole moiety, methyl groups, and backbone of rumbrin, respectively. Label-dilution experiments with pyrrole-2-carboxylate confirmed it was a direct precursor in the biosynthesis of rumbrin. Both 3- and 4-chloropyrrolecarboxylates were also accepted as precursors in polyene production.
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1OB05667K
Abstract: The biosynthesis of the pyrrolyl moiety of the fungal metabolite rumbrin originates from pyrrole-2-carboxylic acid. In an effort to produce novel derivatives with enhanced biological activity a series of substituted pyrrole-2-carboxylates were synthesised and incubated with the producing organism, Auxarthron umbrinum. Several 4-halo-pyrrole-2-carboxylic acids were incorporated into the metabolite yielding three new derivatives: 3-fluoro-, 3-chloro- and 3-bromo-isorumbrin, which were generated in milligram quantities enabling cytotoxicity assays to be conducted. The 3-chloro- and 3-bromo-isorumbrins had improved activity against HeLa cells compared with rumbrin 3-bromoisorumbrin also showed dramatically improved activity towards a lung cancer cell line (A549).
Publisher: Proceedings of the National Academy of Sciences
Date: 25-03-2008
Abstract: In all probability, natural selection began as ancient marine microorganisms were required to compete for limited resources. These pressures resulted in the evolution of erse genetically encoded small molecules with a variety of ecological and metabolic roles. Remarkably, many of these same biologically active molecules have potential utility in modern medicine and biomedical research. The most promising of these natural products often derive from organisms richly populated by associated microorganisms (e.g., marine sponges and ascidians), and often there is great uncertainty about which organism in these assemblages is making these intriguing metabolites. To use the molecular machinery responsible for the biosynthesis of potential drug-lead natural products, new tools must be applied to delineate their genetic and enzymatic origins. The aim of this perspective is to highlight both traditional and emerging techniques for the localization of metabolic pathways within complex marine environments. Ex les are given from the literature as well as recent proof-of-concept experiments from the authors' laboratories.
Publisher: American Chemical Society (ACS)
Date: 31-12-2009
DOI: 10.1021/NP8003529
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 11-2012
Publisher: American Chemical Society (ACS)
Date: 30-01-2020
DOI: 10.1021/ACS.JNATPROD.9B00315
Abstract: A chemical investigation of a Chinese
Publisher: American Chemical Society (ACS)
Date: 13-07-2011
DOI: 10.1021/NP200323E
Publisher: Elsevier BV
Date: 11-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B600959J
Abstract: Chemical analysis of a solid phase fermentation of an Australian Penicillium citrinum strain has returned all known ex les of a rare class of N-methyl quinolone lactams, quinolactacins A2 (1), B2 (2), C2 (3) and A1 (4), together with the new quinolactacins B1 (5), C1 (6), D1 (7) and D2 (8), and the novel derivatives quinolonimide (9) and quinolonic acid (10). Complete stereostructures were assigned to all these compounds by detailed spectroscopic analysis and chemical interconversion. Carefully controlled and monitored decomposition studies have confirmed that quinolactacins readily undergo C-3 epimerization and oxidation, and under appropriate conditions convert to quinolonimide and quinolonic acid. Mechanisms for key transformations are proposed. The decomposition studies suggested that only quinolactacins A2 (1) and B2 (2) are genuine natural products, with all other isolated compounds being decomposition artefacts. Quinolactacins C1 (6), C2 (3), and the racemic mixture of quinolactacins D1/D2 (8/7) all displayed notable cytotoxic activity.
Publisher: American Chemical Society (ACS)
Date: 28-10-2005
DOI: 10.1021/NP0503101
Abstract: The new isoprenylated diketopiperazine roquefortine E (6) has been isolated from an Australian soil isolate of the ascomycete Gymnoascus reessii. The known fungal metabolite roquefortine C (1) was also recovered as the major antibacterial principle, and all structures were assigned by detailed spectroscopic analysis.
Publisher: American Chemical Society (ACS)
Date: 20-02-2007
DOI: 10.1021/NP0605283
Abstract: Addition of NaCl to the solid-phase fermentation of an Australian isolate of Gymnoascus reessii resulted in enhanced production of chloropolyenylpyrroles, while the addition of NaBr suppressed chloropolyenylpyrrole production in favor of bromo and dechloro analogues. Access to a wider selection of polyenylpyrroles provided scope for SAR comparisons on this rare class of cytotoxic natural products, with the bromo- and dechloropolyenylpyrroles displaying significantly reduced cytotoxicity. These results suggest that the chloro substituent is a critical element in the pharmacophore for this rare class of natural product.
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B816345F
Abstract: Some iturin A-producing strains of Bacillus subtilis will elaborate the novel fluorinated analogue when incubated with 3-fluoro-L-tyrosine. The activity of iturin A is dependent on the D-tyrosine residue and the presence of fluorotyrosine may result in an improvement of the biological properties of this lipopeptide. The fluorinated iturin might also be used as a probe for studying its interaction with biological membranes.
Publisher: American Chemical Society (ACS)
Date: 22-07-2005
DOI: 10.1021/NP050145P
Abstract: Three new aromatic butenolides, gymnoascolides A-C (1-3), have been isolated from the Australian soil ascomycete Gymnoascus reessii and assigned structures on the basis of detailed spectroscopic analysis. The absolute configurations of gymnoascolides B (2) and C (3) at C-5 were solved using a combination of chemical derivatization and quantum chemical simulations.
Publisher: Elsevier BV
Date: 08-2021
Publisher: Springer Science and Business Media LLC
Date: 20-04-2018
Publisher: Springer Science and Business Media LLC
Date: 10-09-2011
DOI: 10.1007/S10532-010-9411-7
Abstract: Fluorinated aromatic compounds are significant environmental pollutants, and microorganisms play important roles in their biodegradation. The effect of fluorine substitution on the transformation of fluorobiphenyl in two bacteria was investigated. Pseudomonas pseudoalcaligenes KF707 and Burkholderia xenovorans LB400 used 2,3,4,5,6-pentafluorobiphenyl and 4,4'-difluorobiphenyl as sole sources of carbon and energy. The catabolism of the fluorinated compounds was examined by gas chromatography-mass spectrometry and fluorine-19 nuclear magnetic resonance spectroscopy (19F NMR), and revealed that the bacteria employed the upper pathway of biphenyl catabolism to degrade these xenobiotics. The novel fluorometabolites 3-pentafluorophenyl-cyclohexa-3,5-diene-1,2-diol and 3-pentafluorophenyl-benzene-1,2-diol were detected in the supernatants of biphenyl-grown resting cells incubated with 2,3,4,5,6-pentafluorobiphenyl, most likely as a consequence of the actions of BphA and BphB. 4-Fluorobenzoate was detected in cultures incubated with 4,4'-difluorobiphenyl and 19F NMR analysis of the supernatant from P. pseudoalcaligenes KF707 revealed the presence of additional water-soluble fluorometabolites.
Publisher: American Chemical Society (ACS)
Date: 03-11-2022
DOI: 10.1021/ACS.JNATPROD.2C00616
Abstract: The secondary metabolite pseudopyronine B, isolated from
Publisher: American Chemical Society (ACS)
Date: 13-08-2008
DOI: 10.1021/NP800088A
Location: United States of America
No related grants have been discovered for Benjamin Clark.