Marine Drugs

Editorial

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3 pages, 179 KiB

Open AccessEditorial

Marine Microbial Diversity as Source of Bioactive Compounds

by Khaled A. Shaaban

Mar. Drugs 2022, 20(5), 304; https://doi.org/10.3390/md20050304 - 29 Apr 2022

Cited by 2 | Viewed by 2286

Abstract

Natural products continue to be a major inspiration and untapped resource for bioactive drug leads/probes [...] Full article

(This article belongs to the Special Issue Marine Microbial Diversity as Source of Bioactive Compounds)

Research

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9 pages, 600 KiB

Open AccessArticle

Mansouramycins E–G, Cytotoxic Isoquinolinequinones from Marine Streptomycetes

by Mohamed Shaaban, Khaled A. Shaaban, Gerhard Kelter, Heinz Herbert Fiebig and Hartmut Laatsch

Mar. Drugs 2021, 19(12), 715; https://doi.org/10.3390/md19120715 - 20 Dec 2021

Cited by 9 | Viewed by 2946

Abstract

Chemical investigation of the ethyl acetate extract from the marine-derived Streptomyces sp. isolate B1848 resulted in three new isoquinolinequinone derivatives, the mansouramycins E–G (1a–3a), in addition to the previously reported mansouramycins A (5) and D (6 [...] Read more.

Chemical investigation of the ethyl acetate extract from the marine-derived Streptomyces sp. isolate B1848 resulted in three new isoquinolinequinone derivatives, the mansouramycins E–G (1a–3a), in addition to the previously reported mansouramycins A (5) and D (6). Their structures were elucidated by computer-assisted interpretation of 1D and 2D NMR spectra, high-resolution mass spectrometry, and by comparison with related compounds. Cytotoxicity profiling of the mansouramycins in a panel of up to 36 tumor cell lines indicated a significant cytotoxicity and good tumor selectivity for mansouramycin F (2a), while the activity profile of E (1a) was less attractive. Full article

(This article belongs to the Special Issue Marine Microbial Diversity as Source of Bioactive Compounds)

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30 pages, 4386 KiB

Open AccessArticle

Metabolomics Tools Assisting Classic Screening Methods in Discovering New Antibiotics from Mangrove Actinomycetia in Leizhou Peninsula

by Qin-Pei Lu, Yong-Mei Huang, Shao-Wei Liu, Gang Wu, Qin Yang, Li-Fang Liu, Hai-Tao Zhang, Yi Qi, Ting Wang, Zhong-Ke Jiang, Jun-Jie Li, Hao Cai, Xiu-Jun Liu, Hui Luo and Cheng-Hang Sun

Mar. Drugs 2021, 19(12), 688; https://doi.org/10.3390/md19120688 - 1 Dec 2021

Cited by 13 | Viewed by 4093

Abstract

Mangrove actinomycetia are considered one of the promising sources for discovering novel biologically active compounds. Traditional bioactivity- and/or taxonomy-based methods are inefficient and usually result in the re-discovery of known metabolites. Thus, improving selection efficiency among strain candidates is of interest especially in [...] Read more.

Mangrove actinomycetia are considered one of the promising sources for discovering novel biologically active compounds. Traditional bioactivity- and/or taxonomy-based methods are inefficient and usually result in the re-discovery of known metabolites. Thus, improving selection efficiency among strain candidates is of interest especially in the early stage of the antibiotic discovery program. In this study, an integrated strategy of combining phylogenetic data and bioactivity tests with a metabolomics-based dereplication approach was applied to fast track the selection process. A total of 521 actinomycetial strains affiliated to 40 genera in 23 families were isolated from 13 different mangrove soil samples by the culture-dependent method. A total of 179 strains affiliated to 40 different genera with a unique colony morphology were selected to evaluate antibacterial activity against 12 indicator bacteria. Of the 179 tested isolates, 47 showed activities against at least one of the tested pathogens. Analysis of 23 out of 47 active isolates using UPLC-HRMS-PCA revealed six outliers. Further analysis using the OPLS-DA model identified five compounds from two outliers contributing to the bioactivity against drug-sensitive A. baumannii. Molecular networking was used to determine the relationship of significant metabolites in six outliers and to find their potentially new congeners. Finally, two Streptomyces strains (M22, H37) producing potentially new compounds were rapidly prioritized on the basis of their distinct chemistry profiles, dereplication results, and antibacterial activities, as well as taxonomical information. Two new trioxacarcins with keto-reduced trioxacarcinose B, gutingimycin B (16) and trioxacarcin G (20), together with known gutingimycin (12), were isolated from the scale-up fermentation broth of Streptomyces sp. M22. Our study demonstrated that metabolomics tools could greatly assist classic antibiotic discovery methods in strain prioritization to improve efficiency in discovering novel antibiotics from those highly productive and rich diversity ecosystems. Full article

(This article belongs to the Special Issue Marine Microbial Diversity as Source of Bioactive Compounds)

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11 pages, 1022 KiB

Open AccessArticle

Cytotoxic Indole-Diterpenoids from the Marine-Derived Fungus Penicillium sp. KFD28

by Lu-Ting Dai, Li Yang, Fan-Dong Kong, Qing-Yun Ma, Qing-Yi Xie, Hao-Fu Dai, Zhi-Fang Yu and You-Xing Zhao

Mar. Drugs 2021, 19(11), 613; https://doi.org/10.3390/md19110613 - 28 Oct 2021

Cited by 20 | Viewed by 2816

Abstract

Four new indole-diterpenoids, named penerpenes K-N (1–4), along with twelve known ones (5–16), were isolated from the fermentation broth produced by adding L-tryptophan to the culture medium of the marine-derived fungus Penicillium sp. KFD28. The [...] Read more.

Four new indole-diterpenoids, named penerpenes K-N (1–4), along with twelve known ones (5–16), were isolated from the fermentation broth produced by adding L-tryptophan to the culture medium of the marine-derived fungus Penicillium sp. KFD28. The structures of the new compounds were elucidated extensively by 1D and 2D NMR, HRESIMS data spectroscopic analyses and ECD calculations. Compound 4 represents the second example of paxilline-type indole diterpene bearing a 1,3-dioxepane ring. Three compounds (4, 9, and 15) were cytotoxic to cancer cell lines, of which compound 9 was the most active and showed cytotoxic activity against the human liver cancer cell line BeL-7402 with an IC₅₀ value of 5.3 μM. Moreover, six compounds (5, 7, 10, 12, 14, and 15) showed antibacterial activities against Staphylococcus aureus ATCC 6538 and Bacillus subtilis ATCC 6633. Full article

(This article belongs to the Special Issue Marine Microbial Diversity as Source of Bioactive Compounds)

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32 pages, 13688 KiB

Open AccessArticle

Marine Sulfated Polysaccharides as Promising Antiviral Agents: A Comprehensive Report and Modeling Study Focusing on SARS CoV-2

by Abdalla E. M. Salih, Bathini Thissera, Mohammed Yaseen, Ahmed S. I. Hassane, Hesham R. El-Seedi, Ahmed M. Sayed and Mostafa E. Rateb

Mar. Drugs 2021, 19(8), 406; https://doi.org/10.3390/md19080406 - 22 Jul 2021

Cited by 39 | Viewed by 6830

Abstract

SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) is a novel coronavirus strain that emerged at the end of 2019, causing millions of deaths so far. Despite enormous efforts being made through various drug discovery campaigns, there is still a desperate need for treatments with [...] Read more.

SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) is a novel coronavirus strain that emerged at the end of 2019, causing millions of deaths so far. Despite enormous efforts being made through various drug discovery campaigns, there is still a desperate need for treatments with high efficacy and selectivity. Recently, marine sulfated polysaccharides (MSPs) have earned significant attention and are widely examined against many viral infections. This article attempted to produce a comprehensive report about MSPs from different marine sources alongside their antiviral effects against various viral species covering the last 25 years of research articles. Additionally, these reported MSPs were subjected to molecular docking and dynamic simulation experiments to ascertain potential interactions with both the receptor-binding domain (RBD) of SARS CoV-2’s spike protein (S-protein) and human angiotensin-converting enzyme-2 (ACE2). The possible binding sites on both S-protein’s RBD and ACE2 were determined based on how they bind to heparin, which has been reported to exhibit significant antiviral activity against SARS CoV-2 through binding to RBD, preventing the virus from affecting ACE2. Moreover, our modeling results illustrate that heparin can also bind to and block ACE2, acting as a competitor and protective agent against SARS CoV-2 infection. Nine of the investigated MSPs candidates exhibited promising results, taking into consideration the newly emerged SARS CoV-2 variants, of which five were not previously reported to exert antiviral activity against SARS CoV-2, including sulfated galactofucan (1), sulfated polymannuroguluronate (SPMG) (2), sulfated mannan (3), sulfated heterorhamnan (8), and chondroitin sulfate E (CS-E) (9). These results shed light on the importance of sulfated polysaccharides as potential SARS-CoV-2 inhibitors. Full article

(This article belongs to the Special Issue Marine Microbial Diversity as Source of Bioactive Compounds)

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16 pages, 4190 KiB

Open AccessArticle

Molecular and Structural Characterizations of Lipases from Chlorella by Functional Genomics

by Hajer Ben Hlima, Mouna Dammak, Aida Karray, Maroua Drira, Philippe Michaud, Imen Fendri and Slim Abdelkafi

Mar. Drugs 2021, 19(2), 70; https://doi.org/10.3390/md19020070 - 28 Jan 2021

Cited by 13 | Viewed by 2983

Abstract

Microalgae have been poorly investigated for new-lipolytic enzymes of biotechnological interest. In silico study combining analysis of sequences homologies and bioinformatic tools allowed the identification and preliminary characterization of 14 putative lipases expressed by Chlorella vulagaris. These proteins have different molecular weights, [...] Read more.

Microalgae have been poorly investigated for new-lipolytic enzymes of biotechnological interest. In silico study combining analysis of sequences homologies and bioinformatic tools allowed the identification and preliminary characterization of 14 putative lipases expressed by Chlorella vulagaris. These proteins have different molecular weights, subcellular localizations, low instability index range and at least 40% of sequence identity with other microalgal lipases. Sequence comparison indicated that the catalytic triad corresponded to residues Ser, Asp and His, with the nucleophilic residue Ser positioned within the consensus GXSXG pentapeptide. 3D models were generated using different approaches and templates and demonstrated that these putative enzymes share a similar core with common α/β hydrolases fold belonging to family 3 lipases and class GX. Six lipases were predicted to have a transmembrane domain and a lysosomal acid lipase was identified. A similar mammalian enzyme plays an important role in breaking down cholesteryl esters and triglycerides and its deficiency causes serious digestive problems in human. More structural insight would provide important information on the enzyme characteristics. Full article

(This article belongs to the Special Issue Marine Microbial Diversity as Source of Bioactive Compounds)

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17 pages, 4277 KiB

Open AccessArticle

Viridicatol Isolated from Deep-Sea Penicillium Griseofulvum Alleviates Anaphylaxis and Repairs the Intestinal Barrier in Mice by Suppressing Mast Cell Activation

by Zhendan Shu, Qingmei Liu, Cuiping Xing, Yafen Zhang, Yu Zhou, Jun Zhang, Hong Liu, Minjie Cao, Xianwen Yang and Guangming Liu

Mar. Drugs 2020, 18(10), 517; https://doi.org/10.3390/md18100517 - 16 Oct 2020

Cited by 16 | Viewed by 3437

Abstract

Viridicatol is a quinoline alkaloid isolated from the deep-sea-derived fungus Penicillium griseofulvum. The structure of viridicatol was unambiguously established by X-ray diffraction analysis. In this study, a mouse model of ovalbumin-induced food allergy and the rat basophil leukemia (RBL)-2H3 cell model were established [...] Read more.

Viridicatol is a quinoline alkaloid isolated from the deep-sea-derived fungus Penicillium griseofulvum. The structure of viridicatol was unambiguously established by X-ray diffraction analysis. In this study, a mouse model of ovalbumin-induced food allergy and the rat basophil leukemia (RBL)-2H3 cell model were established to explore the anti-allergic properties of viridicatol. On the basis of the mouse model, we found viridicatol to alleviate the allergy symptoms; decrease the levels of specific immunoglobulin E, mast cell protease-1, histamine, and tumor necrosis factor-α; and promote the production of interleukin-10 in the serum. The treatment of viridicatol also downregulated the population of B cells and mast cells (MCs), as well as upregulated the population of regulatory T cells in the spleen. Moreover, viridicatol alleviated intestinal villi injury and inhibited the degranulation of intestinal MCs to promote intestinal barrier repair in mice. Furthermore, the accumulation of Ca²⁺ in RBL-2H3 cells was significantly suppressed by viridicatol, which could block the activation of MCs. Taken together, these data indicated that deep-sea viridicatol may represent a novel therapeutic for allergic diseases. Full article

(This article belongs to the Special Issue Marine Microbial Diversity as Source of Bioactive Compounds)

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Review

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21 pages, 5436 KiB

Open AccessReview

Culturable Microorganisms Associated with Sea Cucumbers and Microbial Natural Products

by Lei Chen, Xiao-Yu Wang, Run-Ze Liu and Guang-Yu Wang

Mar. Drugs 2021, 19(8), 461; https://doi.org/10.3390/md19080461 - 16 Aug 2021

Cited by 11 | Viewed by 4027

Abstract

Sea cucumbers are a class of marine invertebrates and a source of food and drug. Numerous microorganisms are associated with sea cucumbers. Seventy-eight genera of bacteria belonging to 47 families in four phyla, and 29 genera of fungi belonging to 24 families in [...] Read more.

Sea cucumbers are a class of marine invertebrates and a source of food and drug. Numerous microorganisms are associated with sea cucumbers. Seventy-eight genera of bacteria belonging to 47 families in four phyla, and 29 genera of fungi belonging to 24 families in the phylum Ascomycota have been cultured from sea cucumbers. Sea-cucumber-associated microorganisms produce diverse secondary metabolites with various biological activities, including cytotoxic, antimicrobial, enzyme-inhibiting, and antiangiogenic activities. In this review, we present the current list of the 145 natural products from microorganisms associated with sea cucumbers, which include primarily polyketides, as well as alkaloids and terpenoids. These results indicate the potential of the microorganisms associated with sea cucumbers as sources of bioactive natural products. Full article

(This article belongs to the Special Issue Marine Microbial Diversity as Source of Bioactive Compounds)

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28 pages, 6561 KiB

Open AccessReview

The Structural Diversity of Marine Microbial Secondary Metabolites Based on Co-Culture Strategy: 2009–2019

by Jianwei Chen, Panqiao Zhang, Xinyi Ye, Bin Wei, Mahmoud Emam, Huawei Zhang and Hong Wang

Mar. Drugs 2020, 18(9), 449; https://doi.org/10.3390/md18090449 - 27 Aug 2020

Cited by 24 | Viewed by 5711

Abstract

Marine microorganisms have drawn great attention as novel bioactive natural product sources, particularly in the drug discovery area. Using different strategies, marine microbes have the ability to produce a wide variety of molecules. One of these strategies is the co-culturing of marine microbes; [...] Read more.

Marine microorganisms have drawn great attention as novel bioactive natural product sources, particularly in the drug discovery area. Using different strategies, marine microbes have the ability to produce a wide variety of molecules. One of these strategies is the co-culturing of marine microbes; if two or more microorganisms are aseptically cultured together in a solid or liquid medium in a certain environment, their competition or synergetic relationship can activate the silent biosynthetic genes to produce cryptic natural products which do not exist in monocultures of the partner microbes. In recent years, the co-cultivation strategy of marine microbes has made more novel natural products with various biological activities. This review focuses on the significant and excellent examples covering sources, types, structures and bioactivities of secondary metabolites based on co-cultures of marine-derived microorganisms from 2009 to 2019. A detailed discussion on future prospects and current challenges in the field of co-culture is also provided on behalf of the authors’ own views of development tendencies. Full article

(This article belongs to the Special Issue Marine Microbial Diversity as Source of Bioactive Compounds)

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