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Open AccessArticle

Antimicrobial Lobophorins from Endophytic Strain Streptomyces sp. R6 Obtained from Azadirachta indica

by Xinyuan Chen, Ying Du, Yunlong Ma, Peibin Liu and Yan Chen

Molecules 2025, 30(3), 586; https://doi.org/10.3390/molecules30030586 - 27 Jan 2025

Cited by 4 | Viewed by 1914

Endophytic bacteria are an important source for developing antimicrobial substances. With the aim to find eco-friendly antimicrobial agents from natural sources, Streptomyces sp. R6 was isolated from Azadirachta indica. After that, a new spirotetronate natural product, lobophorin S (compound 2), together [...] Read more.

Endophytic bacteria are an important source for developing antimicrobial substances. With the aim to find eco-friendly antimicrobial agents from natural sources, Streptomyces sp. R6 was isolated from Azadirachta indica. After that, a new spirotetronate natural product, lobophorin S (compound 2), together with lobophorin H8 (compound 1) and a known macrolide compound divergolide C (compound 3) were isolated from the cultural solution of strain R6. These compounds mark the first isolation of marine-derived microbial natural products known as lobophorins (LOBs) from endophytic bacteria. The structures of these three compounds were identified by extensive NMR and HRMS analyses. The antimicrobial activities of these three compounds against eight fungal and four bacterial phytopathogens were separately evaluated. Compound 1 demonstrated better antibacterial activity against Erwinia carotovora, Pseudomonas syringae pv. tomato, and P. syringae pv. lachrymans with MIC values of 3.91, 7.81, and 15.63 μg/mL, respectively. Additionally, compounds 1–3 all showed antifungal activity against Botrytis cinerea, with the MIC values of 1.95, 7.81, and 15.63 μg/mL, respectively. Notably, the in vivo antifungal effect of 1 against B. cinerea was up to 78.51 ± 3.80% at 1.95 µg/mL, significantly surpassing polyoxin B (70.70 ± 3.81%). These results highlight the potential of lobophorins as promising lead compounds for the development of new, sustainable agents to control plant diseases. Full article

(This article belongs to the Section Natural Products Chemistry)

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9 pages, 1873 KB

Open AccessCommunication

The Isolation and Structure Elucidation of Spirotetronate Lobophorins A, B, and H8 from Streptomyces sp. CB09030 and Their Biosynthetic Gene Cluster

by Jie Shi, Dian Peng, Fei-Fei Peng, Qing-Bo Zhang, Yan-Wen Duan and Yong Huang

Molecules 2023, 28(8), 3597; https://doi.org/10.3390/molecules28083597 - 20 Apr 2023

Cited by 7 | Viewed by 2938

Abstract

Lobophorins (LOBs) are a growing family of spirotetronate natural products with significant cytotoxicity, anti-inflammatory, and antibacterial activities. Herein, we report the transwell-based discovery of Streptomyces sp. CB09030 from a panel of 16 in-house Streptomyces strains, which has significant anti-mycobacterial activity and produces LOB [...] Read more.

Lobophorins (LOBs) are a growing family of spirotetronate natural products with significant cytotoxicity, anti-inflammatory, and antibacterial activities. Herein, we report the transwell-based discovery of Streptomyces sp. CB09030 from a panel of 16 in-house Streptomyces strains, which has significant anti-mycobacterial activity and produces LOB A (1), LOB B (2), and LOB H8 (3). Genome sequencing and bioinformatic analyses revealed the potential biosynthetic gene cluster (BGC) for 1–3, which is highly homologous with the reported BGCs for LOBs. However, the glycosyltransferase LobG1 in S. sp. CB09030 has certain point mutations compared to the reported LobG1. Finally, LOB analogue 4 (O-β-D-kijanosyl-(1→17)-kijanolide) was obtained through an acid-catalyzed hydrolysis of 2. Compounds 1–4 showed different antibacterial activities against Mycobacterium smegmatis and Bacillus subtilis, which revealed the varying roles of different sugars in their antibacterial activities. Full article

(This article belongs to the Special Issue Natural Products with Antiviral, Anti-inflammatory and Immunomodulatory Activities)

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11 pages, 1118 KB

Open AccessArticle

Classification and Secondary Metabolite-Biosynthetic Gene Clusters of Marine Streptomyces Strains Including a Lobophorin- and Divergolide-Producer

by Hisayuki Komaki, Tomohiko Tamura and Yasuhiro Igarashi

Hydrobiology 2023, 2(1), 151-161; https://doi.org/10.3390/hydrobiology2010010 - 1 Feb 2023

Cited by 6 | Viewed by 3909

Abstract

Two Streptomyces strains, named N11-26 and DC10-5, were isolated from deep-sea and non-photosynthetic stony coral, respectively. Strain N11-26 produces lobophorin C and divergolides, which are antimicrobial substances. This study aimed to classify these strains and reveal their cryptic potential to synthesize other secondary [...] Read more.

Two Streptomyces strains, named N11-26 and DC10-5, were isolated from deep-sea and non-photosynthetic stony coral, respectively. Strain N11-26 produces lobophorin C and divergolides, which are antimicrobial substances. This study aimed to classify these strains and reveal their cryptic potential to synthesize other secondary metabolites, such as polyketides and nonribosomal peptides. Strains N11-26 and DC10-5 showed 16S rRNA gene sequence similarities of 100% and 99.9% to Streptomyces olivaceus NRRL B-3009^T, respectively. By digital DNA–DNA hybridization using whole-genome sequences, these strains were classified as Streptomyces olivaceus. Strain N11-26 was closer to the type strain of S. olivaceus than strain DC10-5 and possessed 17 clusters of polyketide synthase (PKS) and/or nonribosomal peptide synthetases (NRPS) genes, whereas strain DC10-5 harbored 19 clusters. Putative products by these gene clusters were predicted by bioinformatic analyses. Although 15 clusters were conserved between the two strains, two and four clusters were specific in strains N11-26 and DC10-5, respectively. This represents a diversity of potential polyketide and nonribosomal peptide compounds between strains of S. olivaceus. To the best of our knowledge, this is the first report annotating all the PKS and NRPS gene clusters in S. olivaceus strains with their putative products to provide useful information for genome mining. Full article

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11 pages, 1509 KB

Open AccessCommunication

Genome Sequencing of Streptomyces olivaceus SCSIO T05 and Activated Production of Lobophorin CR4 via Metabolic Engineering and Genome Mining

by Chunyan Zhang, Wenjuan Ding, Xiangjing Qin and Jianhua Ju

Mar. Drugs 2019, 17(10), 593; https://doi.org/10.3390/md17100593 - 20 Oct 2019

Cited by 22 | Viewed by 5468

Abstract

Marine-sourced actinomycete genus Streptomyces continues to be an important source of new natural products. Here we report the complete genome sequence of deep-sea-derived Streptomyces olivaceus SCSIO T05, harboring 37 putative biosynthetic gene clusters (BGCs). A cryptic BGC for type I polyketides was activated [...] Read more.

Marine-sourced actinomycete genus Streptomyces continues to be an important source of new natural products. Here we report the complete genome sequence of deep-sea-derived Streptomyces olivaceus SCSIO T05, harboring 37 putative biosynthetic gene clusters (BGCs). A cryptic BGC for type I polyketides was activated by metabolic engineering methods, enabling the discovery of a known compound, lobophorin CR4 (1). Genome mining yielded a putative lobophorin BGC (lbp) that missed the functional FAD-dependent oxidoreductase to generate the d-kijanose, leading to the production of lobophorin CR4 without the attachment of d-kijanose to C17-OH. Using the gene-disruption method, we confirmed that the lbp BGC accounts for lobophorin biosynthesis. We conclude that metabolic engineering and genome mining provide an effective approach to activate cryptic BGCs. Full article

(This article belongs to the Special Issue Bioactive Marine Heterocyclic Compounds)

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25 pages, 9923 KB

Open AccessReview

Marine Macrolides with Antibacterial and/or Antifungal Activity

by Tomasz M. Karpiński

Mar. Drugs 2019, 17(4), 241; https://doi.org/10.3390/md17040241 - 23 Apr 2019

Cited by 90 | Viewed by 11811

Abstract

Currently, the increasing resistance of microorganisms to antibiotics is a serious problem. Marine organisms are the source of thousands of substances, which also have antibacterial and antifungal effects. Among them, marine macrolides are significant. In this review, the antibacterial and/or antifungal activities of [...] Read more.

Currently, the increasing resistance of microorganisms to antibiotics is a serious problem. Marine organisms are the source of thousands of substances, which also have antibacterial and antifungal effects. Among them, marine macrolides are significant. In this review, the antibacterial and/or antifungal activities of 34 groups of marine macrolides are presented. Exemplary groups are chalcomycins, curvulides, halichondramides, lobophorins, macrolactins, modiolides, scytophycins, spongistatins, or zearalanones. In the paper, 74 antibiotics or their analog sets, among which 29 with antifungal activity, 25 that are antibacterial, and 20 that are both antifungal and antibacterial are summarized. Also, 36 macrolides or their sets are produced by bacteria, 18 by fungi, ten by sponges, seven by algae, two by porifera, and one by nudibranch. Moreover, the chemical structures of representatives from each of the 34 groups of these antibiotics are presented. To summarize, marine organisms are rich in natural macrolides. Some of these may be used in the future in the treatment of bacterial and fungal infections. Marine macrolides can also be potential drugs applicable against pathogens resistant to currently known antibiotics. Full article

(This article belongs to the Special Issue Marine Macrolides: Structure, Biosynthetic Aspects and Potential as a New Drugs)

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8 pages, 716 KB

Open AccessArticle

Lobophorin K, a New Natural Product with Cytotoxic Activity Produced by Streptomyces sp. M-207 Associated with the Deep-Sea Coral Lophelia pertusa

by Alfredo F. Braña, Aida Sarmiento-Vizcaíno, Miguel Osset, Ignacio Pérez-Victoria, Jesús Martín, Nuria De Pedro, Mercedes De la Cruz, Caridad Díaz, Francisca Vicente, Fernando Reyes, Luis A. García and Gloria Blanco

Mar. Drugs 2017, 15(5), 144; https://doi.org/10.3390/md15050144 - 19 May 2017

Cited by 64 | Viewed by 9335

Abstract

The present article describes the isolation of a new natural product of the lobophorin family, designated as lobophorin K (1), from cultures of the marine actinobacteria Streptomyces sp. M-207, previously isolated from the cold-water coral Lophelia pertusa collected at 1800 m [...] Read more.

The present article describes the isolation of a new natural product of the lobophorin family, designated as lobophorin K (1), from cultures of the marine actinobacteria Streptomyces sp. M-207, previously isolated from the cold-water coral Lophelia pertusa collected at 1800 m depth during an expedition to the submarine Avilés Canyon. Its structure was determined using a combination of spectroscopic techniques, mainly ESI-TOF MS and 1D and 2D NMR. This new natural product displayed cytotoxic activity against two human tumor cell lines, such as pancreatic carcinoma (MiaPaca-2) and breast adenocarcinoma (MCF-7). Lobophorin K also displayed moderate and selective antibiotic activity against pathogenic Gram-positive bacteria such as Staphylococcus aureus. Full article

(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)

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11 pages, 988 KB

Open AccessArticle

New Spirotetronate Antibiotics, Lobophorins H and I, from a South China Sea-Derived Streptomyces sp. 12A35

by Hua-Qi Pan, Song-Ya Zhang, Nan Wang, Zhan-Lin Li, Hui-Ming Hua, Jiang-Chun Hu and Shu-Jin Wang

Mar. Drugs 2013, 11(10), 3891-3901; https://doi.org/10.3390/md11103891 - 15 Oct 2013

Cited by 58 | Viewed by 8653

Abstract

Strain 12A35 was isolated from a deep-sea sediment collected from the South China Sea and showed promising antibacterial activities. It was identified as Streptomyces sp. by the 16S rDNA sequence analysis. Bioassay-guided fractionation using HP20 adsorption, flash chromatography over silica gel and octadecylsilyl [...] Read more.

Strain 12A35 was isolated from a deep-sea sediment collected from the South China Sea and showed promising antibacterial activities. It was identified as Streptomyces sp. by the 16S rDNA sequence analysis. Bioassay-guided fractionation using HP20 adsorption, flash chromatography over silica gel and octadecylsilyl (ODS) and semi-preparative HPLC, led to the isolation and purification of five metabolites from the fermentation culture of 12A35. Two new spirotetronate antibiotics, lobophorins H (1) and I (2), along with three known analogues, O-β-kijanosyl-(1→17)-kijanolide (3), lobophorins B (4) and F (5) were characterized by 1D, 2D-NMR and MS data. These compounds exhibited significant inhibitory activities against Bacillus subtilis. Compounds 1 and 5 exhibited moderate activities against Staphylococcus aureus. In particular, the new compound lobophorin H (1) showed similar antibacterial activities against B. subtilis CMCC63501 to ampicillin. Full article

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10 pages, 584 KB

Open AccessArticle

Lobophorin C and D, New Kijanimicin Derivatives from a Marine Sponge-Associated Actinomycetal Strain AZS17

by Rong-Bian Wei, Tao Xi, Jing Li, Ping Wang, Fu-Chao Li, Yong-Cheng Lin and Song Qin

Mar. Drugs 2011, 9(3), 359-368; https://doi.org/10.3390/md9030359 - 17 Mar 2011

Cited by 69 | Viewed by 13481

Abstract

Marine sponge Hymeniacidon sp. was collected from coastal waters of the East China Sea to isolate symbiotic microorganisms. The resulting sponge-associated actinomycete, Streptomyces carnosus strain AZS17, was cultivated in a 20 L volume of medium for production of bioactive secondary metabolites. Bioassay-guided isolation [...] Read more.

Marine sponge Hymeniacidon sp. was collected from coastal waters of the East China Sea to isolate symbiotic microorganisms. The resulting sponge-associated actinomycete, Streptomyces carnosus strain AZS17, was cultivated in a 20 L volume of medium for production of bioactive secondary metabolites. Bioassay-guided isolation and purification by varied chromatographic methods yielded two new compounds of kijanimicin derivatives, AS7-2 and AS9-12. Their structures were elucidated by spectroscopy and comparison with literatures. Results showed these two compounds were structurally similar to the previously reported compounds lobophorin A and B, yet differed in specific bond forms, stereochemistry and optical activities. The two novel compounds were named lobophorin C and D. In vitro cytotoxicity investigation by MTT assay indicated their selective activities. Lobophorin C displayed potent cytotoxic activity against the human liver cancer cell line 7402, while lobophorin D showed significant inhibitory effect on human breast cancer cells MDA-MB 435. Full article

(This article belongs to the Special Issue Marine Antibiotics)

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