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Special Issue "Marine Anti-infective Agents"

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A special issue of Marine Drugs (ISSN 1660-3397).

Deadline for manuscript submissions: closed (31 October 2014)

Special Issue Editor

Guest Editor
Prof. Dr. Miguel O. Mitchell

Science Content Editor,Late Nite Labs, 1309 Middle Neck Dr. Apt. J Salisbury, MD 21804, USA
Phone: +1 410 422 2695
Interests: rational design and synthesis of antitubercular; anti-MRSA; anti-VRE and anticholinesterase agents; indole alkaloid natural product synthesis

Special Issue Information

Dear Colleagues,

This Special Issue will include both primary research and review articles covering anti-infective agents discovered in marine organisms. These anti-infective agents may be antibacterial, antifungal, antiprotozoan, antitubercular, and antiviral agents. These marine compounds may directlly interfere with microbial replication, block virulence (e.g., quorum sensing antagonists), or reverse multidrug resistance. Primary research articles must include full characterization (proton NMR, carbon-13 NMR, and high resolution mass spectral data) of all new compounds. Review articles must cite peer-reviewed literature from five years prior to the year of publication, e.g., a 2015 review should cite articles published from 2010-2014.

Prof. Dr. Miguel O. Mitchell
Guest Editor

Keywords

  • antibacterial
  • antitrypanosomal
  • antimycobacterial
  • antitubercular, tuberculosis
  • antifungal
  • antiviral
  • antimalarial, malaria
  • antiprotozoal
  • antimonial, Leishmania

Published Papers (19 papers)

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Research

Jump to: Review

Open AccessCommunication Sulfated Steroid–Amino Acid Conjugates from the Irish Marine Sponge Polymastia boletiformis
Mar. Drugs 2015, 13(4), 1632-1646; doi:10.3390/md13041632
Received: 12 December 2014 / Revised: 23 February 2015 / Accepted: 16 March 2015 / Published: 24 March 2015
PDF Full-text (611 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Antifungal bioactivity-guided fractionation of the organic extract of the sponge Polymastia boletiformis, collected from the west coast of Ireland, led to the isolation of two new sulfated steroid-amino acid conjugates (1 and 2). Extensive 1D and 2D NMR analyses [...] Read more.
Antifungal bioactivity-guided fractionation of the organic extract of the sponge Polymastia boletiformis, collected from the west coast of Ireland, led to the isolation of two new sulfated steroid-amino acid conjugates (1 and 2). Extensive 1D and 2D NMR analyses in combination with quantum mechanical calculations of the electronic circular dichroism (ECD) spectra, optical rotation, and 13C chemical shifts were used to establish the chemical structures of 1 and 2. Both compounds exhibited moderate antifungal activity against Cladosporium cucumerinum, while compound 2 was also active against Candida albicans. Marine natural products containing steroidal and amino acid constituents are extremely rare in nature. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
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Open AccessArticle Sulphated Polysaccharides from Ulva clathrata and Cladosiphon okamuranus Seaweeds both Inhibit Viral Attachment/Entry and Cell-Cell Fusion, in NDV Infection
Mar. Drugs 2015, 13(2), 697-712; doi:10.3390/md13020697
Received: 31 October 2014 / Accepted: 6 January 2015 / Published: 26 January 2015
Cited by 7 | PDF Full-text (816 KB) | HTML Full-text | XML Full-text
Abstract
Sulphated polysaccharides (SP) extracted from seaweeds have antiviral properties and are much less cytotoxic than conventional drugs, but little is known about their mode of action. Combination antiviral chemotherapy may offer advantages over single agent therapy, increasing efficiency, potency and delaying the [...] Read more.
Sulphated polysaccharides (SP) extracted from seaweeds have antiviral properties and are much less cytotoxic than conventional drugs, but little is known about their mode of action. Combination antiviral chemotherapy may offer advantages over single agent therapy, increasing efficiency, potency and delaying the emergence of resistant virus. The paramyxoviridae family includes pathogens causing morbidity and mortality worldwide in humans and animals, such as the Newcastle Disease Virus (NDV) in poultry. This study aims at determining the antiviral activity and mechanism of action in vitro of an ulvan (SP from the green seaweed Ulva clathrata), and of its mixture with a fucoidan (SP from Cladosiphon okamuranus), against La Sota NDV strain. The ulvan antiviral activity was tested using syncytia formation, exhibiting an IC50 of 0.1 μg/mL; ulvan had a better anti cell-cell spread effect than that previously shown for fucoidan, and inhibited cell-cell fusion via a direct effect on the F0 protein, but did not show any virucidal effect. The mixture of ulvan and fucoidan showed a greater anti-spread effect than SPs alone, but ulvan antagonizes the effect of fucoidan on the viral attachment/entry. Both SPs may be promising antivirals against paramyxovirus infection but their mixture has no clear synergistic advantage. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
Open AccessArticle Marine-Derived Quorum-Sensing Inhibitory Activities Enhance the Antibacterial Efficacy of Tobramycin against Pseudomonas aeruginosa
Mar. Drugs 2015, 13(1), 1-28; doi:10.3390/md13010001
Received: 27 October 2014 / Accepted: 15 December 2014 / Published: 24 December 2014
Cited by 2 | PDF Full-text (1421 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Bacterial epiphytes isolated from marine eukaryotes were screened for the production of quorum sensing inhibitory compounds (QSIs). Marine isolate KS8, identified as a Pseudoalteromonas sp., was found to display strong quorum sensing inhibitory (QSI) activity against acyl homoserine lactone (AHL)-based reporter strains [...] Read more.
Bacterial epiphytes isolated from marine eukaryotes were screened for the production of quorum sensing inhibitory compounds (QSIs). Marine isolate KS8, identified as a Pseudoalteromonas sp., was found to display strong quorum sensing inhibitory (QSI) activity against acyl homoserine lactone (AHL)-based reporter strains Chromobacterium violaceum ATCC 12472 and CV026. KS8 supernatant significantly reduced biofilm biomass during biofilm formation (−63%) and in pre-established, mature P. aeruginosa PAO1 biofilms (−33%). KS8 supernatant also caused a 0.97-log reduction (−89%) and a 2-log reduction (−99%) in PAO1 biofilm viable counts in the biofilm formation assay and the biofilm eradication assay respectively. The crude organic extract of KS8 had a minimum inhibitory concentration (MIC) of 2 mg/mL against PAO1 but no minimum bactericidal concentration (MBC) was observed over the concentration range tested (MBC > 16 mg/mL). Sub-MIC concentrations (1 mg/mL) of KS8 crude organic extract significantly reduced the quorum sensing (QS)-dependent production of both pyoverdin and pyocyanin in P. aeruginosa PAO1 without affecting growth. A combinatorial approach using tobramycin and the crude organic extract at 1 mg/mL against planktonic P. aeruginosa PAO1 was found to increase the efficacy of tobramycin ten-fold, decreasing the MIC from 0.75 to 0.075 µg/mL. These data support the validity of approaches combining conventional antibiotic therapy with non-antibiotic compounds to improve the efficacy of current treatments. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
Open AccessArticle Geographic Variability and Anti-Staphylococcal Activity of the Chrysophaentins and Their Synthetic Fragments
Mar. Drugs 2012, 10(5), 1103-1125; doi:10.3390/md10051103
Received: 15 April 2012 / Revised: 5 May 2012 / Accepted: 7 May 2012 / Published: 22 May 2012
Cited by 6 | PDF Full-text (1020 KB) | HTML Full-text | XML Full-text
Abstract
Drug-resistant Staphylococcus aureus is a continuing public health concern, both in the hospital and community settings. Antibacterial compounds that possess novel structural scaffolds and are effective against multiple S. aureus strains, including current drug-resistant ones, are needed. Previously, we have described the [...] Read more.
Drug-resistant Staphylococcus aureus is a continuing public health concern, both in the hospital and community settings. Antibacterial compounds that possess novel structural scaffolds and are effective against multiple S. aureus strains, including current drug-resistant ones, are needed. Previously, we have described the chrysophaentins, a family of bisdiarylbutene macrocycles from the chrysophyte alga Chrysophaeum taylori that inhibit the growth of S. aureus and methicillin-resistant S. aureus (MRSA). In this study we have analyzed the geographic variability of chrysophaentin production in C. taylori located at different sites on the island of St. John, U.S. Virgin Islands, and identified two new linear chrysophaentin analogs, E2 and E3. In addition, we have expanded the structure activity relationship through synthesis of fragments comprising conserved portions of the chrysophaentins, and determined the antimicrobial activity of natural chrysophaentins and their synthetic analogs against five diverse S. aureus strains. We find that the chrysophaentins show similar activity against all S. aureus strains, regardless of their drug sensitivity profiles. The synthetic chrysophaentin fragments indeed mimic the natural compounds in their spectrum of antibacterial activity, and therefore represent logical starting points for future medicinal chemistry studies of the natural products and their analogs. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
Open AccessArticle Antibacterial Secondary Metabolites from the Cave Sponge Xestospongia sp.
Mar. Drugs 2012, 10(5), 1037-1043; doi:10.3390/md10051037
Received: 5 March 2012 / Revised: 24 April 2012 / Accepted: 1 May 2012 / Published: 7 May 2012
Cited by 8 | PDF Full-text (192 KB) | HTML Full-text | XML Full-text
Abstract
Chemical investigation of the cave sponge Xestospongia sp. resulted in the isolation of three new polyacetylenic long chain compounds along with two known metabolites. The structures of the new metabolites were established by NMR and MS analyses. The antibacterial activity of the [...] Read more.
Chemical investigation of the cave sponge Xestospongia sp. resulted in the isolation of three new polyacetylenic long chain compounds along with two known metabolites. The structures of the new metabolites were established by NMR and MS analyses. The antibacterial activity of the new metabolites was also evaluated. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
Open AccessArticle Structural Characterization and Anti-HSV-1 and HSV-2 Activity of Glycolipids from the Marine Algae Osmundaria obtusiloba Isolated from Southeastern Brazilian Coast
Mar. Drugs 2012, 10(4), 918-931; doi:10.3390/md10040918
Received: 5 March 2012 / Revised: 11 April 2012 / Accepted: 17 April 2012 / Published: 23 April 2012
Cited by 18 | PDF Full-text (3759 KB) | HTML Full-text | XML Full-text
Abstract
Glycolipids were extracted from the red alga Osmundaria obtusiloba from Southeastern Brazilian coast. The acetone insoluble material was extracted with chloroform/methanol and the lipids, enriched in glycolipids, were fractionated on a silica gel column eluted with chloroform, acetone and then methanol. Three [...] Read more.
Glycolipids were extracted from the red alga Osmundaria obtusiloba from Southeastern Brazilian coast. The acetone insoluble material was extracted with chloroform/methanol and the lipids, enriched in glycolipids, were fractionated on a silica gel column eluted with chloroform, acetone and then methanol. Three major orcinol-positive bands were found in the acetone and methanol fractions, being detected by thin layer chromatography. The structures of the corresponding glycolipids were elucidated by ESI-MS and 1H/13C NMR analysis, on the basis of their tandem-MS behavior and HSQC, TOCSY fingerprints. For the first time, the structure of sulfoquinovosyldiacylglycerol from the red alga Osmundaria obtusiloba was characterized. This molecule exhibited potent antiviral activity against HSV-1 and HSV-2 with EC50 values of 42 µg/mL to HSV-1 and 12 µg/mL to HSV-2, respectively. Two other glycolipids, mono- and digalactosyldiacylglycerol, were also found in the alga, being characterized by ESI-MS/MS. The structural elucidation of algae glycolipids is a first step for a better understanding of the relation between these structures and their biological activities. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
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Open AccessArticle Epigenetic Tailoring for the Production of Anti-Infective Cytosporones from the Marine Fungus Leucostoma persoonii
Mar. Drugs 2012, 10(4), 762-774; doi:10.3390/md10040762
Received: 22 February 2012 / Revised: 13 March 2012 / Accepted: 20 March 2012 / Published: 28 March 2012
Cited by 25 | PDF Full-text (408 KB) | HTML Full-text | XML Full-text
Abstract
Recent genomic studies have demonstrated that fungi can possess gene clusters encoding for the production of previously unobserved secondary metabolites. Activation of these attenuated or silenced genes to obtain either improved titers of known compounds or new ones altogether has been a [...] Read more.
Recent genomic studies have demonstrated that fungi can possess gene clusters encoding for the production of previously unobserved secondary metabolites. Activation of these attenuated or silenced genes to obtain either improved titers of known compounds or new ones altogether has been a subject of considerable interest. In our efforts to discover new chemotypes that are effective against infectious diseases, including malaria and methicillin-resistant Staphylococcus aureus (MRSA), we have isolated a strain of marine fungus, Leucostoma persoonii, that produces bioactive cytosporones. Epigenetic modifiers employed to activate secondary metabolite genes resulted in enhanced production of known cytosporones B (1, 360%), C (2, 580%) and E (3, 890%), as well as the production of the previously undescribed cytosporone R (4). Cytosporone E was the most bioactive, displaying an IC90 of 13 µM toward Plasmodium falciparum, with A549 cytotoxicity IC90 of 437 µM, representing a 90% inhibition therapeutic index (TI90 = IC90 A459/IC90 P. falciparum) of 33. In addition, cytosporone E was active against MRSA with a minimal inhibitory concentration (MIC) of 72 µM and inhibition of MRSA biofilm at roughly half that value (minimum biofilm eradication counts, MBEC90, was found to be 39 µM). Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
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Open AccessArticle Antiviral Activities and Putative Identification of Compounds in Microbial Extracts from the Hawaiian Coastal Waters
Mar. Drugs 2012, 10(3), 521-538; doi:10.3390/md10030521
Received: 25 December 2011 / Revised: 3 February 2012 / Accepted: 6 February 2012 / Published: 24 February 2012
Cited by 5 | PDF Full-text (973 KB) | HTML Full-text | XML Full-text
Abstract
Marine environments are a rich source of significant bioactive compounds. The Hawaiian archipelago, located in the middle of the Pacific Ocean, hosts diverse microorganisms, including many endemic species. Thirty-eight microbial extracts from Hawaiian coastal waters were evaluated for their antiviral activity against [...] Read more.
Marine environments are a rich source of significant bioactive compounds. The Hawaiian archipelago, located in the middle of the Pacific Ocean, hosts diverse microorganisms, including many endemic species. Thirty-eight microbial extracts from Hawaiian coastal waters were evaluated for their antiviral activity against four mammalian viruses including herpes simplex virus type one (HSV-1), vesicular stomatitis virus (VSV), vaccinia virus and poliovirus type one (poliovirus-1) using in vitro cell culture assay. Nine of the 38 microbial crude extracts showed antiviral potencies and three of these nine microbial extracts exhibited significant activity against the enveloped viruses. A secosteroid, 5α(H),17α(H),(20R)-beta-acetoxyergost-8(14)-ene was putatively identified and confirmed to be the active compound in these marine microbial extracts. These results warrant future in-depth tests on the isolation of these active elements in order to explore and validate their antiviral potential as important therapeutic remedies. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
Open AccessArticle Tasco®: A Product of Ascophyllum nodosum Enhances Immune Response of Caenorhabditis elegans Against Pseudomonas aeruginosa Infection
Mar. Drugs 2012, 10(1), 84-105; doi:10.3390/md10010084
Received: 28 November 2011 / Revised: 27 December 2011 / Accepted: 5 January 2012 / Published: 11 January 2012
Cited by 11 | PDF Full-text (533 KB) | HTML Full-text | XML Full-text
Abstract
The effects of Tasco®, a product made from the brown seaweed (Ascophyllum nodosum) were tested for the ability to protect Caenorhabditis elegans against Pseudomonas aeruginosa infection. A water extract of Tasco® (TWE) reduced P. aeruginosa inflicted mortality [...] Read more.
The effects of Tasco®, a product made from the brown seaweed (Ascophyllum nodosum) were tested for the ability to protect Caenorhabditis elegans against Pseudomonas aeruginosa infection. A water extract of Tasco® (TWE) reduced P. aeruginosa inflicted mortality in the nematode. The TWE, at a concentration of 300 µg/mL, offered the maximum protection and induced the expression of innate immune response genes viz.; zk6.7 (Lypases), lys-1 (Lysozyme), spp-1 (Saponin like protein), f28d1.3 (Thaumatin like protein), t20g5.7 (Matridin SK domain protein), abf-1 (Antibacterial protein) and f38a1.5 (Lectin family protein). Further, TWE treatment also affected a number of virulence components of the P. aeuroginosa and reduced its secreted virulence factors such as lipase, proteases and toxic metabolites; hydrogen cyanide and pyocyanin. Decreased virulence factors were associated with a significant reduction in expression of regulatory genes involved in quorum sensing, lasI, lasR, rhlI and rhlR. In conclusion, the TWE-treatment protected the C. elegans against P. aeruginosa infection by a combination of effects on the innate immunity of the worms and direct effects on the bacterial quorum sensing and virulence factors. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
Open AccessArticle Inhibition of Virulence Gene Expression in Staphylococcus aureus by Novel Depsipeptides from a Marine Photobacterium
Mar. Drugs 2011, 9(12), 2537-2552; doi:10.3390/md9122537
Received: 22 September 2011 / Revised: 22 November 2011 / Accepted: 30 November 2011 / Published: 7 December 2011
Cited by 38 | PDF Full-text (2518 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
During a global research expedition, more than five hundred marine bacterial strains capable of inhibiting the growth of pathogenic bacteria were collected. The purpose of the present study was to determine if these marine bacteria are also a source of compounds that [...] Read more.
During a global research expedition, more than five hundred marine bacterial strains capable of inhibiting the growth of pathogenic bacteria were collected. The purpose of the present study was to determine if these marine bacteria are also a source of compounds that interfere with the agr quorum sensing system that controls virulence gene expression in Staphylococcus aureus. Using a gene reporter fusion bioassay, we recorded agr interference as enhanced expression of spa, encoding Protein A, concomitantly with reduced expression of hla, encoding α-hemolysin, and rnaIII encoding RNAIII, the effector molecule of agr. A marine Photobacterium produced compounds interfering with agr in S. aureus strain 8325-4, and bioassay-guided fractionation of crude extracts led to the isolation of two novel cyclodepsipeptides, designated solonamide A and B. Northern blot analysis confirmed the agr interfering activity of pure solonamides in both S. aureus strain 8325-4 and the highly virulent, community-acquired strain USA300 (CA-MRSA). To our knowledge, this is the first report of inhibitors of the agr system by a marine bacterium. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
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Open AccessArticle Bacteriophages with Potential for Inactivation of Fish Pathogenic Bacteria: Survival, Host Specificity and Effect on Bacterial Community Structure
Mar. Drugs 2011, 9(11), 2236-2255; doi:10.3390/md9112236
Received: 22 September 2011 / Revised: 21 October 2011 / Accepted: 28 October 2011 / Published: 7 November 2011
Cited by 17 | PDF Full-text (1227 KB) | HTML Full-text | XML Full-text
Abstract
Phage therapy may represent a viable alternative to antibiotics to inactivate fish pathogenic bacteria. Its use, however, requires the awareness of novel kinetics phenomena not applied to conventional drug treatments. The main objective of this work was to isolate bacteriophages with potential [...] Read more.
Phage therapy may represent a viable alternative to antibiotics to inactivate fish pathogenic bacteria. Its use, however, requires the awareness of novel kinetics phenomena not applied to conventional drug treatments. The main objective of this work was to isolate bacteriophages with potential to inactivate fish pathogenic bacteria, without major effects on the structure of natural bacterial communities of aquaculture waters. The survival was determined in marine water, through quantification by the soft agar overlay technique. The host specificity was evaluated by cross infection. The ecological impact of phage addition on the structure of the bacterial community was evaluated by DGGE of PCR amplified 16S rRNA gene fragments. The survival period varied between 12 and 91 days, with a higher viability for Aeromonas salmonicida phages. The phages of Vibrio parahaemolyticus and of A. salmonicida infected bacteria of different families with a high efficacy of plating. The specific phages of pathogenic bacteria had no detectable impact on the structure of the bacterial community. In conclusion, V. parahaemolyticus and A. salmonicida phages show good survival time in marine water, have only a moderated impact on the overall bacterial community structure and the desired specificity for host pathogenic bacteria, being potential candidates for therapy of fish infectious diseases in marine aquaculture systems. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
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Open AccessCommunication Anti-Parasitic Compounds from Streptomyces sp. Strains Isolated from Mediterranean Sponges
Mar. Drugs 2010, 8(2), 373-380; doi:10.3390/md8020373
Received: 26 December 2009 / Revised: 2 February 2010 / Accepted: 4 February 2010 / Published: 23 February 2010
Cited by 58 | PDF Full-text (183 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Actinomycetes are prolific producers of pharmacologically important compounds accounting for about 70% of the naturally derived antibiotics that are currently in clinical use. In this study, we report on the isolation of Streptomyces sp. strains from Mediterranean sponges, on their secondary metabolite production and on their screening for anti-infective activities. Bioassay-guided isolation and purification yielded three previously known compounds namely, cyclic depsipeptide valinomycin, indolocarbazole alkaloid staurosporine and butenolide. This is the first report of the isolation of valinomycin from a marine source. These compounds exhibited novel anti-parasitic activities specifically against Leishmania major (valinomycin IC50 < 0.11 µM; staurosporine IC50 5.30 µM) and Trypanosoma brucei brucei (valinomycin IC50 0.0032 µM; staurosporine IC50 0.022 µM; butenolide IC50 31.77 µM). These results underscore the potential of marine actinomycetes to produce bioactive compounds as well as the re-evaluation of previously known compounds for novel anti-infective activities. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
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Review

Jump to: Research

Open AccessReview Marine Peptides and Their Anti-Infective Activities
Mar. Drugs 2015, 13(1), 618-654; doi:10.3390/md13010618
Received: 11 November 2014 / Accepted: 1 January 2015 / Published: 16 January 2015
Cited by 13 | PDF Full-text (1268 KB) | HTML Full-text | XML Full-text
Abstract
Marine bioresources are a valuable source of bioactive compounds with industrial and nutraceutical potential. Numerous clinical trials evaluating novel chemotherapeutic agents derived from marine sources have revealed novel mechanisms of action. Recently, marine-derived bioactive peptides have attracted attention owing to their numerous [...] Read more.
Marine bioresources are a valuable source of bioactive compounds with industrial and nutraceutical potential. Numerous clinical trials evaluating novel chemotherapeutic agents derived from marine sources have revealed novel mechanisms of action. Recently, marine-derived bioactive peptides have attracted attention owing to their numerous beneficial effects. Moreover, several studies have reported that marine peptides exhibit various anti-infective activities, such as antimicrobial, antifungal, antimalarial, antiprotozoal, anti-tuberculosis, and antiviral activities. In the last several decades, studies of marine plants, animals, and microbes have revealed tremendous number of structurally diverse and bioactive secondary metabolites. However, the treatments available for many infectious diseases caused by bacteria, fungi, and viruses are limited. Thus, the identification of novel antimicrobial peptides should be continued, and all possible strategies should be explored. In this review, we will present the structures and anti-infective activity of peptides isolated from marine sources (sponges, algae, bacteria, fungi and fish) from 2006 to the present. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
Open AccessReview Seaweed Polysaccharides and Derived Oligosaccharides Stimulate Defense Responses and Protection Against Pathogens in Plants
Mar. Drugs 2011, 9(12), 2514-2525; doi:10.3390/md9122514
Received: 8 September 2011 / Revised: 17 November 2011 / Accepted: 18 November 2011 / Published: 29 November 2011
Cited by 47 | PDF Full-text (297 KB) | HTML Full-text | XML Full-text
Abstract
Plants interact with the environment by sensing “non-self” molecules called elicitors derived from pathogens or other sources. These molecules bind to specific receptors located in the plasma membrane and trigger defense responses leading to protection against pathogens. In particular, it has been [...] Read more.
Plants interact with the environment by sensing “non-self” molecules called elicitors derived from pathogens or other sources. These molecules bind to specific receptors located in the plasma membrane and trigger defense responses leading to protection against pathogens. In particular, it has been shown that cell wall and storage polysaccharides from green, brown and red seaweeds (marine macroalgae) corresponding to ulvans, alginates, fucans, laminarin and carrageenans can trigger defense responses in plants enhancing protection against pathogens. In addition, oligosaccharides obtained by depolymerization of seaweed polysaccharides also induce protection against viral, fungal and bacterial infections in plants. In particular, most seaweed polysaccharides and derived oligosaccharides trigger an initial oxidative burst at local level and the activation of salicylic (SA), jasmonic acid (JA) and/or ethylene signaling pathways at systemic level. The activation of these signaling pathways leads to an increased expression of genes encoding: (i) Pathogenesis-Related (PR) proteins with antifungal and antibacterial activities; (ii) defense enzymes such as pheylalanine ammonia lyase (PAL) and lipoxygenase (LOX) which determine accumulation of phenylpropanoid compounds (PPCs) and oxylipins with antiviral, antifugal and antibacterial activities and iii) enzymes involved in synthesis of terpenes, terpenoids and/or alkaloids having antimicrobial activities. Thus, seaweed polysaccharides and their derived oligosaccharides induced the accumulation of proteins and compounds with antimicrobial activities that determine, at least in part, the enhanced protection against pathogens in plants. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
Open AccessReview Conventional and Unconventional Antimicrobials from Fish, Marine Invertebrates and Micro-algae
Mar. Drugs 2010, 8(4), 1213-1262; doi:10.3390/md8041213
Received: 8 February 2010 / Revised: 2 April 2010 / Accepted: 12 April 2010 / Published: 14 April 2010
Cited by 62 | PDF Full-text (531 KB) | HTML Full-text | XML Full-text
Abstract
All eukaryotic organisms, single-celled or multi-cellular, produce a diverse array of natural anti-infective agents that, in addition to conventional antimicrobial peptides, also include proteins and other molecules often not regarded as part of the innate defences. Examples range from histones, fatty acids, [...] Read more.
All eukaryotic organisms, single-celled or multi-cellular, produce a diverse array of natural anti-infective agents that, in addition to conventional antimicrobial peptides, also include proteins and other molecules often not regarded as part of the innate defences. Examples range from histones, fatty acids, and other structural components of cells to pigments and regulatory proteins. These probably represent very ancient defence factors that have been re-used in new ways during evolution. This review discusses the nature, biological role in host protection and potential biotechnological uses of some of these compounds, focusing on those from fish, marine invertebrates and marine micro-algae. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
Open AccessReview Novel Anti-Infective Compounds from Marine Bacteria
Mar. Drugs 2010, 8(3), 498-518; doi:10.3390/md8030498
Received: 3 February 2010 / Revised: 1 March 2010 / Accepted: 2 March 2010 / Published: 5 March 2010
Cited by 52 | PDF Full-text (277 KB) | HTML Full-text | XML Full-text
Abstract
As a result of the continuous evolution of microbial pathogens towards antibiotic-resistance, there have been demands for the development of new and effective antimicrobial compounds. Since the 1960s, the scientific literature has accumulated many publications about novel pharmaceutical compounds produced by a [...] Read more.
As a result of the continuous evolution of microbial pathogens towards antibiotic-resistance, there have been demands for the development of new and effective antimicrobial compounds. Since the 1960s, the scientific literature has accumulated many publications about novel pharmaceutical compounds produced by a diverse range of marine bacteria. Indeed, marine micro-organisms continue to be a productive and successful focus for natural products research, with many newly isolated compounds possessing potentially valuable pharmacological activities. In this regard, the marine environment will undoubtedly prove to be an increasingly important source of novel antimicrobial metabolites, and selective or targeted approaches are already enabling the recovery of a significant number of antibiotic-producing micro-organisms. The aim of this review is to consider advances made in the discovery of new secondary metabolites derived from marine bacteria, and in particular those effective against the so called “superbugs”, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin resistant enterococci (VRE), which are largely responsible for the increase in numbers of hospital acquired, i.e., nosocomial, infections. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
Open AccessReview Marine-Derived Metabolites of S-Adenosylmethionine as Templates for New Anti-Infectives
Mar. Drugs 2009, 7(3), 401-434; doi:10.3390/md7030401
Received: 30 July 2009 / Revised: 20 August 2009 / Accepted: 24 August 2009 / Published: 26 August 2009
Cited by 11 | PDF Full-text (193 KB) | HTML Full-text | XML Full-text
Abstract
S-Adenosylmethionine (AdoMet) is a key biochemical co-factor whose proximate metabolites include methylated macromolecules (e.g., nucleic acids, proteins, phospholipids), methylated small molecules (e.g., sterols, biogenic amines), polyamines (e.g., spermidine, spermine), ethylene, and N-acyl-homoserine lactones. Marine [...] Read more.
S-Adenosylmethionine (AdoMet) is a key biochemical co-factor whose proximate metabolites include methylated macromolecules (e.g., nucleic acids, proteins, phospholipids), methylated small molecules (e.g., sterols, biogenic amines), polyamines (e.g., spermidine, spermine), ethylene, and N-acyl-homoserine lactones. Marine organisms produce numerous AdoMet metabolites whose novel structures can be regarded as lead compounds for anti-infective drug design. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
Open AccessReview Phage Therapy and Photodynamic Therapy: Low Environmental Impact Approaches to Inactivate Microorganisms in Fish Farming Plants
Mar. Drugs 2009, 7(3), 268-313; doi:10.3390/md7030268
Received: 21 May 2009 / Revised: 22 June 2009 / Accepted: 25 June 2009 / Published: 30 June 2009
Cited by 39 | PDF Full-text (890 KB) | HTML Full-text | XML Full-text
Abstract
Owing to the increasing importance of aquaculture to compensate for the progressive worldwide reduction of natural fish and to the fact that several fish farming plants often suffer from heavy financial losses due to the development of infections caused by microbial pathogens, [...] Read more.
Owing to the increasing importance of aquaculture to compensate for the progressive worldwide reduction of natural fish and to the fact that several fish farming plants often suffer from heavy financial losses due to the development of infections caused by microbial pathogens, including multidrug resistant bacteria, more environmentally-friendly strategies to control fish infections are urgently needed to make the aquaculture industry more sustainable. The aim of this review is to briefly present the typical fish farming diseases and their threats and discuss the present state of chemotherapy to inactivate microorganisms in fish farming plants as well as to examine the new environmentally friendly approaches to control fish infection namely phage therapy and photodynamic antimicrobial therapy. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
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Open AccessReview Marine Antimalarials
Mar. Drugs 2009, 7(2), 130-152; doi:10.3390/md7020130
Received: 7 April 2009 / Revised: 20 April 2009 / Accepted: 22 April 2009 / Published: 23 April 2009
Cited by 53 | PDF Full-text (328 KB) | HTML Full-text | XML Full-text
Abstract
Malaria is an infectious disease causing at least 1 million deaths per year, and, unfortunately, the chemical entities available to treat malaria are still too limited. In this review we highlight the contribution of marine chemistry in the field of antimalarial research [...] Read more.
Malaria is an infectious disease causing at least 1 million deaths per year, and, unfortunately, the chemical entities available to treat malaria are still too limited. In this review we highlight the contribution of marine chemistry in the field of antimalarial research by reporting the most important results obtained until the beginning of 2009, with particular emphasis on recent discoveries. About 60 secondary metabolites produced by marine organisms have been grouped into three structural types and discussed in terms of their reported antimalarial activities. The major groups of metabolites include isonitrile derivatives, alkaloids and endoperoxide derivatives. The following discussion evidences that antimalarial marine molecules can efficiently integrate the panel of lead compounds isolated from terrestrial sources with new chemical backbones and, sometimes, with unique functional groups. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
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