Marine Drugs

Research

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15 pages, 611 KiB

Open AccessCommunication

Sulfated Steroid–Amino Acid Conjugates from the Irish Marine Sponge Polymastia boletiformis

by Vangelis Smyrniotopoulos, Margaret Rae, Sylvia Soldatou, Yuanqing Ding, Carsten W. Wolff, Grace McCormack, Christina M. Coleman, Daneel Ferreira and Deniz Tasdemir

Mar. Drugs 2015, 13(4), 1632-1646; https://doi.org/10.3390/md13041632 - 24 Mar 2015

Cited by 12 | Viewed by 6353

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 in [...] 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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16 pages, 816 KiB

Open AccessArticle

Sulphated Polysaccharides from Ulva clathrata and Cladosiphon okamuranus Seaweeds both Inhibit Viral Attachment/Entry and Cell-Cell Fusion, in NDV Infection

by José Alberto Aguilar-Briseño, Lucia Elizabeth Cruz-Suarez, Jean-François Sassi, Denis Ricque-Marie, Pablo Zapata-Benavides, Edgar Mendoza-Gamboa, Cristina Rodríguez-Padilla and Laura María Trejo-Avila

Mar. Drugs 2015, 13(2), 697-712; https://doi.org/10.3390/md13020697 - 26 Jan 2015

Cited by 142 | Viewed by 12025

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 emergence [...] 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)

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28 pages, 1421 KiB

Open AccessArticle

Marine-Derived Quorum-Sensing Inhibitory Activities Enhance the Antibacterial Efficacy of Tobramycin against Pseudomonas aeruginosa

by Alessandro Busetti, George Shaw, Julianne Megaw, Sean P. Gorman, Christine A. Maggs and Brendan F. Gilmore

Mar. Drugs 2015, 13(1), 1-28; https://doi.org/10.3390/md13010001 - 24 Dec 2014

Cited by 39 | Viewed by 11274

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 Chromobacterium [...] 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)

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23 pages, 1020 KiB

Open AccessArticle

Geographic Variability and Anti-Staphylococcal Activity of the Chrysophaentins and Their Synthetic Fragments

by Jessica L. Keffer, Jared T. Hammill, John R. Lloyd, Alberto Plaza, Peter Wipf and Carole A. Bewley

Mar. Drugs 2012, 10(5), 1103-1125; https://doi.org/10.3390/md10051103 - 22 May 2012

Cited by 18 | Viewed by 8546

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 chrysophaentins, [...] 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)

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7 pages, 192 KiB

Open AccessArticle

Antibacterial Secondary Metabolites from the Cave Sponge Xestospongia sp.

by Sridevi Ankisetty and Marc Slattery

Mar. Drugs 2012, 10(5), 1037-1043; https://doi.org/10.3390/md10051037 - 7 May 2012

Cited by 29 | Viewed by 7607

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 new [...] 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)

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14 pages, 3759 KiB

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

by Lauro M. De Souza, Guilherme L. Sassaki, Maria Teresa Villela Romanos and Eliana Barreto-Bergter

Mar. Drugs 2012, 10(4), 918-931; https://doi.org/10.3390/md10040918 - 23 Apr 2012

Cited by 76 | Viewed by 10553

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 major [...] 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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13 pages, 408 KiB

Open AccessArticle

Epigenetic Tailoring for the Production of Anti-Infective Cytosporones from the Marine Fungus Leucostoma persoonii

by Jeremy Beau, Nida Mahid, Whittney N. Burda, Lacey Harrington, Lindsey N. Shaw, Tina Mutka, Dennis E. Kyle, Betty Barisic, Alberto Van Olphen and Bill J. Baker

Mar. Drugs 2012, 10(4), 762-774; https://doi.org/10.3390/md10040762 - 28 Mar 2012

Cited by 90 | Viewed by 11169

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 subject [...] 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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18 pages, 973 KiB

Open AccessArticle

Antiviral Activities and Putative Identification of Compounds in Microbial Extracts from the Hawaiian Coastal Waters

by Jing Tong, Hank Trapido-Rosenthal, Jun Wang, Youwei Wang, Qing X. Li and Yuanan Lu

Mar. Drugs 2012, 10(3), 521-538; https://doi.org/10.3390/md10030521 - 24 Feb 2012

Cited by 16 | Viewed by 9612

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 four [...] 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)

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22 pages, 533 KiB

Open AccessArticle

Tasco^®: A Product of Ascophyllum nodosum Enhances Immune Response of Caenorhabditis elegans Against Pseudomonas aeruginosa Infection

by Saveetha Kandasamy, Wajahatullah Khan, Franklin Evans, Alan T. Critchley and Balakrishnan Prithiviraj

Mar. Drugs 2012, 10(1), 84-105; https://doi.org/10.3390/md10010084 - 11 Jan 2012

Cited by 35 | Viewed by 11249

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 in [...] 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)

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16 pages, 2518 KiB

Open AccessArticle

Inhibition of Virulence Gene Expression in Staphylococcus aureus by Novel Depsipeptides from a Marine Photobacterium

by Maria Mansson, Anita Nielsen, Louise Kjærulff, Charlotte H. Gotfredsen, Matthias Wietz, Hanne Ingmer, Lone Gram and Thomas O. Larsen

Mar. Drugs 2011, 9(12), 2537-2552; https://doi.org/10.3390/md9122537 - 7 Dec 2011

Cited by 110 | Viewed by 13982

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 interfere [...] 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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20 pages, 1227 KiB

Open AccessArticle

Bacteriophages with Potential for Inactivation of Fish Pathogenic Bacteria: Survival, Host Specificity and Effect on Bacterial Community Structure

by Carla Pereira, Yolanda J. Silva, Ana L. Santos, Ângela Cunha, Newton C. M. Gomes and Adelaide Almeida

Mar. Drugs 2011, 9(11), 2236-2255; https://doi.org/10.3390/md9112236 - 7 Nov 2011

Cited by 75 | Viewed by 10934

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 to [...] 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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8 pages, 183 KiB

Open AccessCommunication

Anti-Parasitic Compounds from Streptomyces sp. Strains Isolated from Mediterranean Sponges

by Sheila Marie Pimentel-Elardo, Svitlana Kozytska, Tim S. Bugni, Chris M. Ireland, Heidrun Moll and Ute Hentschel

Mar. Drugs 2010, 8(2), 373-380; https://doi.org/10.3390/md8020373 - 23 Feb 2010

Cited by 176 | Viewed by 19678

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 [...] Read more.

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

37 pages, 1268 KiB

Open AccessReview

Marine Peptides and Their Anti-Infective Activities

by Hee Kyoung Kang, Chang Ho Seo and Yoonkyung Park

Mar. Drugs 2015, 13(1), 618-654; https://doi.org/10.3390/md13010618 - 16 Jan 2015

Cited by 142 | Viewed by 14185

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 beneficial [...] 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)

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12 pages, 297 KiB

Open AccessReview

Seaweed Polysaccharides and Derived Oligosaccharides Stimulate Defense Responses and Protection Against Pathogens in Plants

by Jeannette Vera, Jorge Castro, Alberto Gonzalez and Alejandra Moenne

Mar. Drugs 2011, 9(12), 2514-2525; https://doi.org/10.3390/md9122514 - 29 Nov 2011

Cited by 323 | Viewed by 18245

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 shown [...] 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)

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50 pages, 531 KiB

Open AccessReview

Conventional and Unconventional Antimicrobials from Fish, Marine Invertebrates and Micro-algae

by Valerie J. Smith, Andrew P. Desbois and Elisabeth A. Dyrynda

Mar. Drugs 2010, 8(4), 1213-1262; https://doi.org/10.3390/md8041213 - 14 Apr 2010

Cited by 232 | Viewed by 19582

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, and [...] 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)

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21 pages, 277 KiB

Open AccessReview

Novel Anti-Infective Compounds from Marine Bacteria

by Hafizur Rahman, Brian Austin, Wilfrid J. Mitchell, Peter C. Morris, Derek J. Jamieson, David R. Adams, Andrew Mearns Spragg and Michael Schweizer

Mar. Drugs 2010, 8(3), 498-518; https://doi.org/10.3390/md8030498 - 5 Mar 2010

Cited by 123 | Viewed by 22160

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 diverse [...] 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)

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34 pages, 193 KiB

Open AccessReview

Marine-Derived Metabolites of S-Adenosylmethionine as Templates for New Anti-Infectives

by Janice R. Sufrin, Steven Finckbeiner and Colin M. Oliver

Mar. Drugs 2009, 7(3), 401-434; https://doi.org/10.3390/md7030401 - 26 Aug 2009

Cited by 27 | Viewed by 13942

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 organisms [...] 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)

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46 pages, 890 KiB

Open AccessReview

Phage Therapy and Photodynamic Therapy: Low Environmental Impact Approaches to Inactivate Microorganisms in Fish Farming Plants

by Adelaide Almeida, Ângela Cunha, Newton C. M. Gomes, Eliana Alves, Liliana Costa and Maria A. F. Faustino

Mar. Drugs 2009, 7(3), 268-313; https://doi.org/10.3390/md7030268 - 30 Jun 2009

Cited by 131 | Viewed by 24509

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, including [...] 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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23 pages, 328 KiB

Open AccessReview

Marine Antimalarials

by Ernesto Fattorusso and Orazio Taglialatela-Scafati

Mar. Drugs 2009, 7(2), 130-152; https://doi.org/10.3390/md7020130 - 23 Apr 2009

Cited by 101 | Viewed by 16177

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 by [...] 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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