Special Issue "Bioactive Compounds from Marine Fungi"
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A special issue of Marine Drugs (ISSN 1660-3397).
Deadline for manuscript submissions: closed (31 January 2013)
Special Issue Editor
Guest Editor
Prof. Dr. Johannes F. Imhoff
Marine Mikrobiologie, IFM-GEOMAR, Düsternbrooker Weg 20, D-24105 Kiel und Kieler Wirkstoff-Zentrum KiWiZ, Am Kiel-Kanal 44, 24106 Kiel, Germany
E-Mail: jimhoff@ifm-geomar.de
Phone: +0431/600-4450 / -4451
Fax: +0431-600-4452
Special Issue Information
Dear Colleagues,
Nature continues to be most important in the delivery of new drugs or lead structures and the oceans are important sources of structurally unique natural products. Among the biota from the oceans marine-derived fungi are an outstanding source for secondary metabolites, many of which have highly complex structures, making them difficult to be supplied economically via chemical synthesis.
Fungi derived from marine sources are considered to represent a huge reservoir of secondary metabolites, many of which are biologically active and are produced e.g. by multifunctional enzyme complexes such as polyketide synthases (PKS) and non-ribosomal peptide synthetases (NRPS). Marine fungi are highly potent producers of bioactive substances with antifungal, antibacterial, antiviral, cytotoxic and immunosuppressive activity. The various biological activities make them a valuable source for pharmaceutical applications.
From an ecological point of view fungal secondary metabolites may act specifically in interspecies interactions to protect the host and/or the producer against competitors and/or diseases. On the other hand, fungal metabolites are considered of great importance in the ecology of marine communities and the analysis of fungal genetics, fungal physiology and fungal natural compound profiles will be essential to understand the interrelationships between fungi and their environment.
In addition, the rapid progress in genomic information significantly stimulates the search for secondary metabolite producers and secondary metabolite biosynthesis. It greatly improves our knowledge on the potential of secondary metabolite production in fungi and already has demonstrated that fungi encode the genetic information for the biosynthesis of many as yet unknown compounds.
This is good reason to devote a special issue of Marine Drugs to the bioactive compounds from marine fungi.
Prof. Dr. Johannes F. Imhoff
Guest Editor
Submission
Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.
Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Marine Drugs is an international peer-reviewed Open Access monthly journal published by MDPI.
Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs).
Keywords
- marine fungi
- fungal genomics
- polyketide synthases
- non-ribosomal peptide synthesis
- antitumoral activity
- antibiotic activity
- fungal secondary metabolites
- secondary metabolite biosynthesis
- fungal secondary metabolites
- fungal interactions
- fungal drugs
Published Papers (8 papers)
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Received: 8 November 2010; in revised form: 15 December 2010 / Accepted: 22 December 2010 / Published: 27 December 2010
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Abstract: The aim of the present study was to investigate indigenous fungal communities isolated from extreme environments (hypersaline waters of solar salterns and subglacial ice), for the production of metabolic compounds with selected biological activities: hemolysis, antibacterial, and acetylcholinesterase inhibition. In their natural habitats, the selected fungi are exposed to environmental extremes, and therefore the production of bioactive metabolites was tested under both standard growth conditions for mesophilic microorganisms, and at high NaCl and sugar concentrations and low growth temperatures. The results indicate that selected halotolerant and halophilic species synthesize specific bioactive metabolites under conditions that represent stress for non-adapted species. Furthermore, adaptation at the level of the chemical nature of the solute lowering the water activity of the medium was observed. Increased salt concentrations resulted in higher hemolytic activity, particularly within species dominating the salterns. The appearance of antibacterial potential under stress conditions was seen in the similar pattern of fungal species as for hemolysis. The active extracts exclusively affected the growth of the Gram-positive bacterium tested, Bacillus subtilis. None of the extracts tested showed inhibition of acetylcholinesterase activity.
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Received: 13 January 2011; in revised form: 11 February 2011 / Accepted: 24 February 2011 / Published: 25 February 2011
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Abstract: In the search for bioactive compounds, 11 fungal strains were isolated from Indonesian marine habitats. Ethyl acetate extracts of their culture broth were tested for cytotoxic activity against a urinary bladder carcinoma cell line and for antifungal and antibacterial activities against fish and human pathogenic bacteria as well as against plant and human pathogenic fungi. The crude extract of a sterile algicolous fungus (KT31), isolated from the red seaweed Kappaphycus alvarezii (Doty) Doty ex P.C. Silva exhibited potent cytotoxic activity with an IC50 value of 1.5 µg/mL. Another fungal strain (KT29) displayed fungicidal properties against the plant pathogenic fungus Cladosporium cucumerinum Ell. et Arth. at 50 µg/spot. 2-Carboxy-8-methoxy-naphthalene-1-ol (1) could be isolated as a new natural product.
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Received: 17 February 2011; in revised form: 1 March 2011 / Accepted: 25 March 2011 / Published: 6 April 2011
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Abstract: Fungi associated with the marine sponge Tethya aurantium were isolated and identified by morphological criteria and phylogenetic analyses based on internal transcribed spacer (ITS) regions. They were evaluated with regard to their secondary metabolite profiles. Among the 81 isolates which were characterized, members of 21 genera were identified. Some genera like Acremonium, Aspergillus, Fusarium, Penicillium, Phoma, and Trichoderma are quite common, but we also isolated strains belonging to genera like Botryosphaeria, Epicoccum, Parasphaeosphaeria, and Tritirachium which have rarely been reported from sponges. Members affiliated to the genera Bartalinia and Volutella as well as to a presumably new Phoma species were first isolated from a sponge in this study. On the basis of their classification, strains were selected for analysis of their ability to produce natural products. In addition to a number of known compounds, several new natural products were identified. The scopularides and sorbifuranones have been described elsewhere. We have isolated four additional substances which have not been described so far. The new metabolite cillifuranone (1) was isolated from Penicillium chrysogenum strain LF066. The structure of cillifuranone (1) was elucidated based on 1D and 2D NMR analysis and turned out to be a previously postulated intermediate in sorbifuranone biosynthesis. Only minor antibiotic bioactivities of this compound were found so far.
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Received: 9 November 2012; in revised form: 29 November 2012 / Accepted: 5 December 2012 / Published: 19 December 2012
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Abstract: The marine-derived filamentous fungus Asteromyces cruciatus 763, obtained off the coast of La Jolla, San Diego, USA, yielded the new pentapeptide lajollamide A (1), along with the known compounds regiolone (2), hyalodendrin (3), gliovictin (4), 1N-norgliovicitin (5), and bis-N-norgliovictin (6). The planar structure of lajollamide A (1) was determined by Nuclear Magnetic Resonance (NMR) spectroscopy in combination with mass spectrometry. The absolute configuration of lajollamide A (1) was unambiguously solved by total synthesis which provided three additional diastereomers of 1 and also revealed that an unexpected acid-mediated partial racemization (2:1) of the l-leucine and l-N-Me-leucine residues occurred during the chemical degradation process. The biological activities of the isolated metabolites, in particular their antimicrobial properties, were investigated in a series of assay systems.
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Zhen-Xing Li, Jian-Wen Chen, Feng Yuan, Yun-Ying Huang, Li-Yan Zhao, Jie Li, Huan-Xing Su, Jie Liu, Ji-Yan Pang, Yong-Cheng Lin, Xi-Lin Lu, Zhong Pei, Guan-Lei Wang and Yong-Yuan Guan
Received: 28 November 2012; in revised form: 22 January 2013 / Accepted: 31 January 2013 / Published: 18 February 2013
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Abstract: We previously reported that a novel marine compound, xyloketal B, has strong antioxidative actions in different models of cardiovascular diseases. Induction of heme oxygenase-1 (HO-1), an important endogenous antioxidant enzyme, has been considered as a potential therapeutic strategy for cardiovascular diseases. We here investigated whether xyloketal B exhibits its antioxidant activity through induction of HO-1. In human umbilical vein endothelial cells (HUVECs), xyloketal B significantly induced HO-1 gene expression and translocation of the nuclear factor-erythroid 2-related factor 2 (Nrf-2) in a concentration- and time-dependent manner. The protection of xyloketal B against angiotensin II-induced apoptosis and reactive oxygen species (ROS) production could be abrogated by the HO-1 specific inhibitor, tin protoporphyrin-IX (SnPP). Consistently, the suppressive effects of xyloketal B on NADPH oxidase activity could be reversed by SnPP in zebrafish embryos. In addition, xyloketal B induced Akt and Erk1/2 phosphorylation in a concentration- and time-dependent manner. Furthermore, PI3K inhibitor LY294002 and Erk1/2 inhibitor U0126 suppressed the induction of HO-1 and translocation of Nrf-2 by xyloketal B, whereas P38 inhibitor SB203580 did not. In conclusion, xyloketal B can induce HO-1 expression via PI3K/Akt/Nrf-2 pathways, and the induction of HO-1 is mainly responsible for the antioxidant and antiapoptotic actions of xyloketal B.
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Received: 21 January 2013; in revised form: 13 February 2013 / Accepted: 18 February 2013 / Published: 22 February 2013
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Abstract: The marine fungus Chondrostereum sp. was collected from a soft coral of the species Sarcophyton tortuosum from the South China Sea. Three new compounds, chondrosterins F–H (1, 4 and 5), together with three known compounds, incarnal (2), arthrosporone (3), and (2E)-decene-4,6,8-triyn-1-ol (6), were isolated. Their structures were elucidated primarily based on NMR and MS data. Incarnal (2) exhibited potent cytotoxic activity against various cancer cell lines.
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Received: 18 December 2012; in revised form: 17 January 2013 / Accepted: 6 February 2013 / Published: 12 March 2013
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Abstract: Microbial studies of the Mediterranean sponge Tethya aurantium led to the isolation of the fungus Bartalinia robillardoides strain LF550. The strain produced a number of secondary metabolites belonging to the chloroazaphilones. This is the first report on the isolation of chloroazaphilones of a fungal strain belonging to the genus Bartalinia. Besides some known compounds (helicusin A (1) and deacetylsclerotiorin (2)), three new chloroazaphilones (helicusin E (3); isochromophilone X (4) and isochromophilone XI (5)) and one new pentaketide (bartanolide (6)) were isolated. The structure elucidations were based on spectroscopic analyses. All isolated compounds revealed different biological activity spectra against a test panel of four bacteria: three fungi; two tumor cell lines and two enzymes.
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Received: 24 January 2013; in revised form: 11 March 2013 / Accepted: 3 April 2013 / Published: 23 April 2013
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Abstract: Protein tyrosine phosphatase 1B (PTP1B) plays a major role in the negative regulation of insulin signaling, and is thus considered as an attractive therapeutic target for the treatment of diabetes. Bioassay-guided investigation of the methylethylketone extract of marine-derived fungus Penicillium sp. JF-55 cultures afforded a new PTP1B inhibitory styrylpyrone-type metabolite named penstyrylpyrone (1), and two known metabolites, anhydrofulvic acid (2) and citromycetin (3). Compounds 1 and 2 inhibited PTP1B activity in a dose-dependent manner, and kinetic analyses of PTP1B inhibition suggested that these compounds inhibited PTP1B activity in a competitive manner. In an effort to gain more biological potential of the isolated compounds, the anti-inflammatory effects of compounds 1–3 were also evaluated. Among the tested compounds, only compound 1 inhibited the production of NO and PGE2, due to the inhibition of the expression of iNOS and COX-2. Penstyrylpyrone (1) also reduced TNF-α and IL-1β production, and these anti-inflammatory effects were shown to be correlated with the suppression of the phosphorylation and degradation of IκB-α, NF-κB nuclear translocation, and NF-κB DNA binding activity. In addition, using inhibitor tin protoporphyrin (SnPP), an inhibitor of HO-1, it was verified that the inhibitory effects of penstyrylpyrone (1) on the pro-inflammatory mediators and NF-κB DNA binding activity were associated with the HO-1 expression. Therefore, these results suggest that penstyrylpyrone (1) suppresses PTP1B activity, as well as the production of pro-inflammatory mediators via NF-κB pathway, through expression of anti-inflammatory HO-1.
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Last update: 10 October 2012
