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Most of the natural products containing tetramic acid have trans configuration of the decalin moiety. Undana A (1), a new cis decalin-bearing tetramic acid metabolite was isolated from endophytic fungi Nigrospora oryzae associated with Avicennia marina. The structure was determined based on the mass and NMR spectral data together with the comparison of the literature. This is the first report of cis decalin-tetramic acid metabolite from the mangrove endophytic fungus. Compound 1 was tested for cytotoxic against L5178Y mouse cancer cells and antibacterial activity against several gram-positive including MRSA and gram-negative bacteria but was found inactive., (© 2024. The Author(s), under exclusive licence to the Japan Antibiotics Research Association.)

Three new α -pyrone derivatives, annularins L-N ( 1 - 3 ), were isolated from the EtOAc extract of Penicillium herquei MA-370, a fungus obtained from the rhizospheric soil of the mangrove plant Rhizophora mucronata. The planar structures of compounds 1 - 3 were determined based on comprehensive spectral interpretation of the NMR and MS data. The absolute configuration of 1 was determined by X-ray crystallographic data and that of 2 was assigned by TDDFT calculations of its ECD spectrum and cotton effects comparison with those of 1 . The antimicrobial activity of compounds 1 - 3 was evaluated.

Two new C 23 -steroids derivatives, cyclocitrinoic acid A ( 1 ) and cyclocitrinoic acid B ( 2 ), and a new isocoumarin metabolite, (3 R ,4 S )-6,8-dihydroxy-3,4,5-trimethyl-7-carboxamidelisocoumarin ( 10 ), together with 12 known compounds ( 3 - 9 , 11 - 15 ) were isolated from the mangrove-sediment fungus Penicillium sp. SCSIO 41429. The structures of the new compounds were comprehensively characterized by 1D and 2D NMR, HRESIMS and ECD calculation. All isolates were evaluated for pancreatic lipase (PL) inhibitory and antioxidant activities. The biological evaluation results revealed that compounds 2 , 14 and 15 displayed weak or moderate inhibition against PL, with IC 50 values of 32.77, 5.15 and 2.42 µM, respectively. In addition, compounds 7 , 12 and 13 showed radical scavenging activities against DPPH, with IC 50 values of 64.70, 48.13, and 75.54 µM, respectively. In addition, molecular docking results indicated that these compounds had potential for PL inhibitory and antioxidant activities, which provided screening candidates for antioxidants and a reduction in obesity.

Positioned at the dynamic interface between terrestrial and marine realms, mangroves embody a vibrant tapestry of biodiversity, encompassing an array of plants, animals, and microorganisms. These microbial inhabitants of mangrove habitats have emerged as a pivotal resource for antimicrobials and a plethora of pharmaceutically valuable compounds, spanning enzymes, antineoplastic agents, pesticides, immunosuppressants, and immunomodulators. This review delves into the recent landscape (January 2021 to May 2024, according to the time of publication) of novel secondary metabolites isolated from mangrove-associated microorganisms, analyzing 41 microbial strains that collectively yielded 165 distinct compounds. Our objective is to assess the productivity and potential of natural products derived from microbial populations within mangrove ecosystems in recent times. Notably, fungi stand out as the preeminent contributors to the emergence of these novel natural products, underscoring their pivotal role in the bioprospecting endeavors within these unique environments., Competing Interests: The authors declare no conflicts of interest.

Four new polyketides, namely furantides A-B ( 1 - 2 ), talamin E ( 3 ) and arugosinacid A ( 4 ), and two known polyketides were obtained from the mangrove-derived fungus Penicillium sp. HDN15-312 using the One Strain Many Compounds (OSMAC) strategy. Their chemical structures, including configurations, were elucidated by detailed analysis of extensive NMR spectra, HRESIMS and ECD. The DPPH radicals scavenging activity of 3 , with an IC 50 value of 6.79 µM, was better than vitamin C.

The fungus Talaromyces hainanensis , isolated from the mangrove soil, was characterized as a novel species by morphology observation and phylogenetic analyses. Four new γ -lactam alkaloids talaroilactams A-D ( 1 - 4 ) and two reported compounds harzianic acid ( 5 ) and isoharzianic acid ( 6 ) were identified from the fungus T. hainanensis WHUF0341, assisted by OSMAC along with molecular networking approaches. Their structures were determined through ECD calculations and spectroscopic analyses. Moreover, the biosynthetic route of 1 - 4 was also proposed. Compound 1 displayed potent cytotoxicity against HepG2 cell lines, with an IC 50 value of 10.75 ± 1.11 μM. In addition, network pharmacology was employed to dissect the probable mechanisms contributing to the antihepatocellular carcinoma effects of compound 1 , revealing that cytotoxicity was mainly associated with proteolysis, negative regulation of autophagy, inflammatory response, and the renin-angiotensin system. These results not only expanded the chemical space of natural products from the mangrove associated fungi but also afforded promising lead compounds for developing the antihepatocellular carcinoma agents.

Melanins are heterogenous biopolymers produced by many macro and microorganisms. They enhance the ecological fitness of the producer organisms by improving their virulence and protecting them from radiation, osmotic and heat stresses. Fungi synthesise either DOPA or DHN melanin and deposit them on their cell walls. Some fungal isolates produce water soluble melanin (pyomelanin) which is excerted out of the hyphae into the surrounding environment. Pyomelanin, a polymer of homogentisate, exhibits antimicrobial, UV screening, antioxidative, and anti-inflammatory activities and recent studies also show that pyomelanin could find use in space travel as radiation shield. However, scant literature is available on fungi with ability to produce pyomelanin. We report for the first time that Amorosia littoralis occurs as a root endophyte in mangrove species including Avicennia marina, Bruguiera cylindrica and Bruguiera gymnorhiza and produces pyomelanin. Considering the various technological uses of pyomelanin, this study underscores the need to explore fungi of different habitats to identify hyperproducers and to obtain chemically diverse pyomelanin., (Copyright © 2024 British Mycological Society. Published by Elsevier Ltd. All rights reserved.)

Co-cultivation is a powerful emerging tool for awakening biosynthetic gene clusters (BGCs) that remain transcriptionally silent under artificial culture conditions. It has recently been used increasingly extensively to study natural interactions and discover new bioactive metabolites. As a part of our project aiming at the discovery of structurally novel and biologically active natural products from mangrove endophytic fungi, an established co-culture of a strain of Phomopsis asparagi DHS-48 with another Phomopsis genus fungus DHS-11, both endophytes in mangrove Rhizophora mangle , proved to be very efficient to induce the production of new metabolites as well as to increase the yields of respective target metabolites. A detailed chemical investigation of the minor metabolites produced by the co-culture of these two titled fungal strains led to the isolation of six alkaloids ( 1 - 6 ), two sterols ( 7 , 8 ), and six polyketides ( 9 - 14 ). In addition, all the compounds except 8 and 10 , as well as three new metabolites phomopyrazine ( 1 ), phomosterol C ( 7 ), and phomopyrone E ( 9 ), were not present in discrete fungal cultures and only detected in the co-cultures. The structures were elucidated on the basis of spectroscopic analysis, and the absolute configurations were assumed by electronic circular dichroism (ECD) calculations. Subsequently, the cytotoxic, immunosuppressive, and acetylcholinesterase inhibitory properties of all the isolated metabolites were determined in vitro. Compound 8 exhibited moderate inhibitory activity against ConA-induced T and LPS-induced B murine splenic lymphocytes, with IC 50 values of 35.75 ± 1.09 and 47.65 ± 1.21 µM, respectively.

Rhizophora extracts have several potential biological activities, and their metabolites can be used in the pharmaceutical industry. Extracts of Rhizophora species obtained from mangroves have shown prospective activity against Staphylococcus aureus. This study aimed to investigate the chemical profile of Rhizophora mangle leaves from fringe, basin, and transition mangrove zones and their bactericidal/bacteriostatic potential against S. aureus. R. mangle leaves were collected monthly in 2018 from litterfall in three different zones of the mangrove of Guaratiba State Reserve: fringe, basin, and transition. Extracts were prepared from the material collected in October and December for LC-HRMS/MS analysis, and dereplication was performed using a molecular library search and the classical molecular networking GNPS platform. The minimum inhibitory concentrations (MICs) of the aqueous extract of R. mangle against S. aureus were determined. No S. aureus growth was observed compared to the control for extracts collected from September to December. Different compounds were annotated in each region, yet a marked presence of phenolic compounds was noted, among them glycosylated flavonoid derivatives of quercetin and kaempferol. The results suggest bactericidal/bacteriostatic activity for extracts of R. mangle leaves collected in 2018 from three mangrove forest zones., (© 2024 Wiley-VHCA AG, Zurich, Switzerland.)

Mangrove derived actinomycetes are a rich reservoir of bioactive natural products and play important roles in pharmaceutical chemistry. In a screen of actinomycetes from mangrove rhizosphere sedimental environments, the isolated strain Streptomyces sp. SCSIO 40068 displayed strong antibacterial activity. Further fractionation of the extract yielded four new compounds kebanmycins A-D ( 1 - 4 ) and two known analogues FD-594 ( 5 ) and the aglycon ( 6 ). The structures of 1 - 6 were determined based on extensive spectroscopic data and single-crystal X-ray diffraction analysis. 1 - 3 featured a fused pyranonaphthaxanthene as an integral part of a 6/6/6/6/6/6 polycyclic motif, and showed bioactivity against a series of Gram-positive bacteria and cytotoxicity to several human tumor cells. In addition, the kebanmycins biosynthetic gene cluster ( keb ) was identified in Streptomyces sp. SCSIO 40068, and KebMT2 was biochemically characterized as a tailoring sugar- O -methyltransferase, leading to a proposed biosynthetic route to 1 - 6 . This study paves the way to further investigate 1 as a potential lead compound.

The mangrove ecosystem plays a crucial role in preserving the biodiversity of plants, animals, and microorganisms that are essential for materials cycles. However, the exploration of endophytic fungi isolated from mangroves, particulary in Santa Catarina (SC, Brazil), remains limited. Therefore, the purpose of this study was to assess the biodiversity of endophytic fungi found in Avicennia schaueriana, Laguncularia racemosa, Rhizophora mangle, and Spartina alterniflora from two mangroves on the Island of Santa Catarina: one impacted by anthropic action (Itacorubi mangrove) and the other environmentally preserved (Ratones mangrove). Samplings were carried out between January 2020 and May 2021. Fungi were isolated from leaves, stems, and roots, identified, and clustered into groups through morphological characteristics. Further, a representative strain of each group was identified through ITS1 sequencing. A total of 373 isolates were obtained from plant tissues, of which 96 and 277 isolates were obtained from Itacorubi and Ratones mangroves, respectively. Molecular identification showed that the endophytic fungal community comprised at least 19 genera. The data on fungal community diversity revealed comparable diversity indices for genera in both mangroves. However, we observed differences in the total frequency of fungal genera between impacted (27.38%) and non-impacted (72.62%) mangroves. These findings suggest that anthropic activities in and around the Santa Catarina mangroves have had negative impact on the frequency of endophytic fungi. This emphasizes the reinforcing the significance of preserving these environments to ensure the maintenance of fungal community diversity., (© 2024. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

Nine metabolites, including three undescribed alkaloids pyripyropenes VW (1-2), penicioxa A (4), two previously reported pyripyropene A (3), oxaline (5), three grisephenone-type xanthone derivatives (6-8), and a diphenyl ether derivative 4-chloro-7,4'-dihydroxy-5,2'-dimethoxy-2-methylformate-6'-methybenzophone (9), were isolated from cultures of the mangrove-derived fungus Penicillium robsamsonii HNNU0006. Their structures were determined by spectroscopic analysis, ECD calculations, together with DP4+ probability analysis. Furthermore, all the isolated compounds were tested for cytotoxicity and anti-phytopathogenic fungal activities. Compounds 6-8 showed moderate cytotoxicity against tumor cell lines A549, with IC 50 values ranging from 5.68 ± 0.21 to 9.71 ± 0.34 μg/mL, respectively., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The mangrove ecosystem is the world's fourth most productive ecosystem in terms of service value and offering rich biological resources. Microorganisms play vital roles in these ecological processes, thus researching the mangroves-microbiota is crucial for a deeper comprehension of mangroves dynamics. Amplicon sequencing that targeted V4 region of 16S rRNA gene was employed to profile the microbial diversities and community compositions of 19 soil samples, which were collected from the rhizosphere of 3 plant species (i.e., Avicennia marina, Ceriops tagal, and Rhizophora mucronata) in the mangrove forests of Lasbela coast, Pakistan. A total of 67 bacterial phyla were observed from three mangroves species, and these taxa were classified into 188 classes, 453 orders, 759 families, and 1327 genera. We found that Proteobacteria (34.9-38.4%) and Desulfobacteria (7.6-10.0%) were the dominant phyla followed by Chloroflexi (6.6-7.3%), Gemmatimonadota (5.4-6.8%), Bacteroidota (4.3-5.5%), Planctomycetota (4.4-4.9%) and Acidobacteriota (2.7-3.4%), Actinobacteriota (2.5-3.3%), and Crenarchaeota (2.5-3.3%). After considering the distribution of taxonomic groups, we prescribe that the distinctions in bacterial community composition and diversity are ascribed to the changes in physicochemical attributes of the soil samples (i.e., electrical conductivity (EC e ), pH, total organic matter (OM), total organic carbon (OC), available phosphorus (P), and extractable potassium (CaCO 3 ). The findings of this study indicated a high-level species diversity in Pakistani mangroves. The outcomes may also aid in the development of effective conservation policies for mangrove ecosystems, which have been hotspots for anthropogenic impacts in Pakistan. To our knowledge, this is the first microbial research from a Pakistani mangrove forest., (© 2023. Institute of Microbiology, Academy of Sciences of the Czech Republic, v.v.i.)

Five new naphthalene derivatives dalesconosides A-D, F ( 1 - 4 , 6 ), a known synthetic analogue named dalesconoside E ( 5 ), and eighteen known compounds ( 7 - 24 ) were isolated from Daldinia eschscholzii MCZ-18, which is an endophytic fungus obtained from the Chinese mangrove plant Ceriops tagal . Differing from previously reported naphthalenes, compounds 1 and 2 were bearing a rare ribofuranoside substituted at C-1 and the 5-methyltetrahydrofuran-2,3-diol moiety, respectively. Their structures were determined by detailed nuclear magnetic resonance (NMR) and mass spectroscopic (MS) analyses, while the absolute configurations were established by theoretical electronic circular dichroism (ECD) calculation. Compounds 1 , 3 , 13 - 17 and 19 showed broad ranges of antimicrobial spectrum against five indicator test microorganisms ( Enterococcus faecalis , Methicillin-resistant Staphylococcus aureus , Escherichia coli , Pseudomonas aeruginosa and Candida albicans ); especially, 1 , 16 and 17 were most potent. The variations in structure and attendant biological activities provided fresh insights concerning structure-activity relationships for the naphthalene derivatives.

The genus Bruguiera , a member of the Rhizophoraceae family, is predominantly found in coastal areas as a mangrove plant, boasting a rich and diverse community of endophytes. This review systematically compiled approximately 496 compounds derived from both the Bruguiera genus and its associated endophytes, including 152 terpenoids, 17 steroids, 16 sulfides, 44 alkaloids and peptides, 66 quinones, 68 polyketides, 19 flavonoids, 38 phenylpropanoids, 54 aromatic compounds, and 22 other compounds. Among these, 201 compounds exhibited a spectrum of activities, including cytotoxicity, antimicrobial, antioxidant, anti-inflammatory, antiviral, antidiabetic, insecticidal and mosquito repellent, and enzyme inhibitory properties, etc. These findings provided promising lead compounds for drug discovery. Certain similar or identical compounds were found to be simultaneously present in both Bruguiera plants and their endophytes, and the phenomenon of their interaction relationship was discussed.

One chromone ( 1 ), together with four known alkaloids, were isolated from the mangrove endophytic fungus Aspergillus sp. ZJ-68. Their structures were elucidated by a combination of HRESIMS and NMR spectroscopic analyses. Compound 1 showed strong anti-inflammatory activity in vitro by inhibiting nitric oxide (NO) production in lipopolysaccharide-activated RAW264.7 cells with an IC 50 value of 4.094 ± 0.8 μM, which was better than positive drug indomethacin (IC 50 =35.8 ± 0.5 μM).

The genus Gallaecimonas, proposed by Rodríguez-Blanco et al. (Int J Syst Evol Microbiol 60:504-509, 2010), is mainly isolated from marine environments. So far, only three species have been identified and characterized in this genus. In this study, a new Gallaecimonas strain named Q10 T was isolated from the sediments of mangrove plant Kandelia obovate taken from Dapeng district, Shenzhen, China. Strain Q10 T was a Gram-stain-negative, non-motile, strictly aerobic, rod-shaped bacterium, and grew with 0-8.0% (w/v) NaCl, at 10-45 °C and at pH 5.5-8.5. Phylogenetic analysis indicated that strain Q10 T and the three Gallaecimonas species formed a clade in the tree, with 16S rRNA gene sequence similarities ranging from 96.0 to 97.0%. The major respiratory quinone is Q8. The polar lipids comprised aminolipid, aminophospholipid, diphosphatidylglycerol, glycolipid, phosphatidylethanolamine, phosphatidylglycerol, glycophospholipid and phospholipid. The predominant fatty acids are C 16:0 , C 17:1 ω8c, summed feature 3 (C 16:1 ω7c/C 16:1 ω6c), and iso-C 16:0 . The complete genome of strain Q10 T is 3,836,841 bp with a G+C content of 62.6 mol%. The orthologous proteins analysis revealed 55 unique proteins in strain Q10 T related to important biological processes, especially three frataxins related to iron-sulfur cluster assembly, which may play a pivotal role in environmental adaptability of this species. Based on polyphasic taxonomic data, strain Q10 T is considered to represent a novel species within the genus Gallaecimonas, for which the name Gallaecimonas kandelia sp. nov. is proposed. The type strain is Q10 T (=KCTC 92860 T =MCCC 1K08421 T ). These results contribute to a better understanding of general features and taxonomy of the genus Gallaecimonas., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Bacterial communities associated with plant propagules remain understudied, despite the opportunities that propagules represent as dispersal vectors for bacteria to new sites. These communities may be the product of a combination of environmental influence and inheritance from parent to offspring. The relative role of these mechanisms could have significant implications for our understanding of plant-microbe interactions. We studied the correlates of microbiome community similarities across an invasion front of red mangroves (Rhizophora mangle L.) in Florida, where the species is expanding northward. We collected georeferenced propagule samples from 110 individuals of red mangroves across 11 populations in Florida and used 16S rRNA gene (iTag) sequencing to describe their bacterial communities. We found no core community of bacterial amplicon sequence variants (ASVs) across the Florida range of red mangroves, though there were some ASVs shared among individuals within most populations. Populations differed significantly as measured by Bray-Curtis dissimilarity, but not Unifrac distance. We generated data from 6 microsatellite loci from 60 individuals across 9 of the 11 populations. Geographic distance was correlated with beta diversity, but genetic distance was not. We conclude that red mangrove propagule bacterial communities are likely influenced more by local environmental acquisition than by inheritance., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Mangrove plants, also known as halophytes, are ecologically important plants that grow in various tropical and subtropical intertidal regions. Owing to the extreme abiotic and biotic stressful conditions they thrive in, these plants produce unique compounds with promising pharmacological propensities. Mangroves are inhabited by an astronomical number of fungal communities which produce a diverse array of extracellular degradative enzymes, namely: amylase, cellulase, xylanase, pectinase, cholesterol oxidase, etc. Such enzymes can be isolated from the mangrove fungi and harnessed for different biotechnological applications, for example, as replacements for chemical catalysts. Mangrove microbes attract considerable attention as they shelter the largest group of marine microorganisms that are resistant to extreme conditions and can produce novel biogenic substances. Vaccines developed from mangrove microbes may promise a safe future by developing effective immunization procedures with a minimum of economic burden. Interestingly, mangroves offer an exciting opportunity for synthesizing nanoparticles in a greener way as these plants are naturally rich in phytochemicals. Rhizophora mucronata Lam., Avicennia officinalis L. and Excoecaria agallocha L. are capable of synthesizing nanoparticles which have evolved recently as an alternative in various industries and are used for their biomedical application. Besides, the phytoconstituents isolated from mangrove plants, such as: gallic acid, galactose, lupeol, catechins, carotenoids, etc., were explored for various biological activities. These compounds are used in the pharmaceutical and nutraceutical industries to produce antimicrobial, antioxidant, anticancer, antidiabetic, and other therapeutic agents. The present review provides information on the biotechnological potentials of mangrove plants and their bioactive compounds as a new source of novel drugs, enzymes, nanoparticles and therapeutically important microbial pigments. Thus, this review forms a base of support and hasten the urgent research on biomedical applications of mangroves.

Mangrove-associated fungi are important sources for the discovery of new bioactive natural products. Three new isocoumarins ( 1 - 3 ) and one new pyrone derivative ( 4 ) were isolated from the ethyl acetate extract of the fermentation broth of the mangrove endophytic fungus Phomopsis sp. DHS-11. Nuclear magnetic resonance (NMR) spectroscopy (one-dimensional and two-dimensional) and mass spectrometry were used to determine the structures of these new compounds. The absolute configurations for the new isocoumarins 1 - 3 were determined by comparing their experimental and calculated electronic circular dichroism (ECD) spectra, while the configuration for the new pyrone-derivative 4 was tentatively solved by comparison of its 13 C NMR data with reported data. In the biological activity test, compounds 1 and 3 showed cytotoxic activity against HeLa cells with IC 50 values of 11.49 ± 1.64 µM and 8.70 ± 0.94 µM, respectively. The initial structure and activity relationship (SAR) analysis revealed that the length of the side chain at C-3 for isocoumarin-type compounds 1 - 3 could affect the cytotoxicity against HeLa cells. Compound 4 exhibited cytotoxic activities against human hepatoma cells HepG2 with an IC 50 value of 34.10 ± 2.92 µM. All compounds have no immunosuppressive activity.

Plant-associated microbial communities may be important sources of functional diversity and genetic variation that influence host evolution. Bacteria provide benefits for their hosts, yet in most plant systems we know little about their taxonomic composition or variation across tissues and host range. Red Mangrove (Rhizophora mangle L.) is a vital coastal plant species that is currently expanding poleward and with it, perhaps, its microbiome. We explored variability in bacterial communities across tissues, individuals, and populations. We collected samples from six sample types from 5 to 10 individuals at each of three populations and used 16S rRNA gene (iTag) sequencing to describe their bacterial communities. Core community members and dominant bacterial classes were determined for each sample type. Pairwise PERMANOVA of Bray-Curtis dissimilarity and Indicator Species Analysis revealed significant differences in bacterial communities between sample types and populations. We described the previously unexplored microbiome of the reproductive tissues of R. mangle. Populations and most sample types were associated with distinct communities. Bacterial communities associated with R. mangle are influenced by host geography and sample type. Our study provides a foundation for future work exploring the functional roles of these microbes and their relevance to biogeochemical cycling., (© The Author(s) 2022. Published by Oxford University Press on behalf of FEMS.)

Chemical investigation of endophytic fungus Aspergillus fumigatus HQD24, isolated from the flower of Rhizophora mucronata led to the isolation of eight alkaloids, including pyripyropene A ( 1 ), 1,11-dideacetyl-pyripyropene A ( 2 ), pyripyropene E ( 3 ), chaetominine ( 4 ), tryptoquivaline J ( 5 ), fumitremorgin C ( 6 ), 1-acetyl-β-carboline ( 7 ), and nicotinic acid ( 8 ). Their structures were unambiguously elucidated on the basis of extensive spectroscopic data and comparison with the data of literature. Compound 2 was known as a synthetic product and isolated as a natural product for the first time. The immunosuppressive and cytotoxic activities of all isolated compounds were evaluated.

Leaf decomposition is the primary process in release of nutrients in the dynamic mangrove habitat, supporting the ecosystem food webs. On most environments, fungi are an essential part of this process. However, due to the peculiarities of mangrove forests, this group is currently neglected. Thus, this study tests the hypothesis that fungal communities display a specific succession pattern in different mangrove species and this due to differences in their ecological role. A molecular approach was employed to investigate the dynamics of the fungal community during the decomposition of three common plant species (Rhizophora mangle, Laguncularia racemosa, and Avicennia schaueriana) from a mangrove habitat located at the southeast of Brazil. Plant material was the primary driver of fungi communities, but time also was marginally significant for the process, and evident changes in the fungal community during the decomposition process were observed. The five most abundant classes common to all the three plant species were Saccharomycetes, Sordariomycetes, Tremellomycetes, Eurotiomycetes, and Dothideomycetes, all belonging to the Phylum Ascomycota. Microbotryomycetes class were shared only by A. schaueriana and L. racemosa, while Agaricomycetes class were shared by L. racemosa and R. mangle. The class Glomeromycetes were shared by A. schaueriana and R. mangle. The analysis of the core microbiome showed that Saccharomycetes was the most abundant class. In the variable community, Sordariomycetes was the most abundant one, mainly in the Laguncularia racemosa plant. The results presented in this work shows a specialization of the fungal community regarding plant material during litter decomposition which might be related to the different chemical composition and rate of degradation., (© 2022. The Author(s).)

In this study, we isolated a novel Gram-stain-positive, aerobic, motile, rod-shaped bacterium, named GX 13764 T , from the rhizosphere soil of a decayed mangrove plant Kandelia candel collected from Beihai, Guangxi, PR China, and characterized using a polyphasic taxonomic approach. The strain exhibited yellow-orange, round, convex, shiny, smooth, opaque and 2-3 mm diameter colonies on marine agar 2216 media after 3 days of incubation at 30 °C and was capable of growth at 4-45 °C (optimum, 30 °C), pH 5.0-9.0 (optimum, pH 7.0) and 0-4 % NaCl (w/v; optimum, 2 %). The strain was positive for catalase and negative for the oxidase. The main cellular fatty acid was anteiso-C 15:0 , iso-C 15:0 , iso-C 16:0 and iso-C 14:0 . The cell-wall peptidoglycan comprised meso -diaminopimelic acid and the main menaquinone was MK-7. The polar lipids included one diphosphatidylglycerol, one phosphatidylglycerol, two glycolipids, two unidentified phospholipids and three unidentified lipids. Based on 16S rRNA gene analysis, GX 13764 T presented the highest sequence similarity to Metabacillus mangrovi KCTC 33872 T (97.04 %). The DNA G+C content of the type strain was 44.2 mol%. The average nucleotide identity values between GX 13764 T and M. mangrovi KCTC 33872 T , Metabacillus idriensis DSM 19097 T and Metabacillus indicus LMG 22858 T were 69.39, 68.87 and 68.95 %, respectively, with digital DNA-DNA hybridization values of 19.9, 19.5 and 19.5 %, respectively. Based on the polyphasic data, strain GX 13764 T should be nominated as a novel species of the genus Metabacillus , for which the name Metabacillus kandeliae sp. nov. is proposed. The type strain is GX 13764 T (=MCCC 1K06654 T =KCTC 43366 T ).

Four new cytochalasans, arbuschalasins A-D (1-4), along with thirteen known analogues (5-17), were isolated from the solid rice medium of endophytic fungus Xylaria arbuscula. Arbuschalasins A-B feature a rare 5/6/6/6 fused ring system while arbuschalasin D was characterized as the first example of natural cytochalasans that possesses a 5/5/11 fused scaffold. The structures of 1-4 were assigned by spectroscopic data, with their absolute structures being determined by electronic circular dichroism (ECD) calculations. All of the isolates were evaluated against the human colorectal adenocarcinoma cell lines (HCT15). Compounds 6 and 7 showed significant inhibitory effects (IC 50 values were 13.5 and 13.4 μM, respectively), being more active than those of the positive control, fluorouracil (103.1 μM)., (Copyright © 2022. Published by Elsevier B.V.)

A novel species of endophytic actinobacterium, designated strain GBK3QG-3 T , was isolated from surface-sterilized root of Kandelia candel collected from Beilun Estuary, Guangxi Zhuang Autonomous Region, PR China. Cells of strain GBK3QG-3 T were Gram-stain-positive, aerobic, non-spore-forming and rod-shaped. Growth of GBK3QG-3 T was observed at 10-40 °C (optimum, 30 °C), pH 5.0-9.0 (optimum, pH 7.0) and in the presence of 0-3 % (w/v) NaCl (optimum, 0 %). The G+C content of genomic DNA was determined to be 72.2 mol%. On the basis of 16S rRNA gene sequence analysis, strain GBK3QG-3 T was most related to the type strain of Nocardioides agrisoli CCTCC AB 2017058 T (97.7 % 16S rRNA gene sequence similarity), followed by Nocardioides ginkgobilobae SYP-A7303 T (97.0 %) and Nocardioides aquiterrae GW-9 T (96.9 %). Average nucleotide identity and digital DNA-DNA hybridization values between strain GBK3QG-3 T and some strains of the genus Nocardioides with publicly available genomes were below 84.3 and 30.0 %, respectively. The cell-wall peptidoglycan contained ll-diaminopimelic acid. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, an unknown phospholipid and an unknown lipid. The major menaquinone was identified as MK-8(H 4 ), and the major fatty acids were identified as iso-C 16 : 0 , iso-C 17 : 0 and anteiso-C 17 : 0 . Based on evidence collected from the phenotypic, genotypic and phylogenetic analyses, we propose a novel species named Nocardioides mangrovi sp. nov. The type strain is GBK3QG-3 T (=CGMCC 4.7708 T =JCM 34553 T ).

Mangrove endophytic fungi are tolerant to numerous stresses and are inevitably capable of exhibiting excellent biological activity by producing impressive numbers of metabolites with special biological functions, based on previous work on the biological potential of mangrove-derived endophytic fungi. To obtain marked antimicrobial and cytotoxic fermentation products of culturable endophytic fungi from mangrove forests, our research evaluated the antimicrobial and cytotoxic activities of crude extracts of endophytic fungi from Rhizophora stylosa and Rhizophora mucronata. Forty-six fungal isolates were cultured on four different media, namely, dextrose agar (PDA), Czapek's agar (CZA), rice medium (RM) and grain medium (GM) and harvested by ethyl acetate solvent at 40 days. The extracts were tested for antimicrobial activity by the microdilution method against the gram-negative bacteria Pseudomonas adaceae (PA), gram-positive bacteria Enterococcus faecalis (EF), methicillin-resistant Staphylococcus aureus (MRSA) and pathogenic fungus Monilia albicans (MA). The cytotoxic activity of the extracts was evaluated by MTT assay using A549 human lung cancer cells, HeLa human cervical carcinoma cells, and HepG2 human hepatocellular cells. The results showed that rice medium could promote the secretion of antimicrobial and antitumour secondary metabolites of endophytic fungi in comparison with other cultivation media. Seventeen strains (68%) from R. stylosa exhibited inhibitory effects on indicators, especially N. protearum HHL46, which could inhibit the growth of four microbes with MIC values reaching 0.0625 mg/mL. Fifteen strains (71.4%) from R. mucronata displayed activities against human pathogenic microbes; in particular, Pestalotiopsis sp. HQD6 and N. protearum HQD5 could resist the growth of four microbes with MIC values ranging from 0.015 to 1 mg/mL. In the cytotoxicity assay, the extracts of 10 strains (40%), 9 strains (40%) and 13 strains (52%) of R. stylosa and 13 strains (61.9%), 10 strains (47.6%) and 10 strains (47.6%) of R. mucronata displayed cytotoxicity against A549, HeLa and HepG2 cancer cells with cell viability values ≤ 50%. Neopestalotiopsis protearum HHL46, Phomopsis longicolla HHL50, Botryosphaeria fusispora HQD83, Fusarium verticillioides HQD48 and Pestalotiopsis sp. HQD6 displayed significant antitumour activity with IC 50 values below 20 μg/mL. These results highlighted the antimicrobial and antitumour potential of endophytic fungi from R. stylosa and R. mucronata and the possibility of exploiting their antimicrobial and cytotoxic agents., (© 2022. The Author(s).)

A Gram-stain-negative, aerobic, motile, non-spore-forming, short-rod-shaped strain that did not produce diffusible pigment, designated CBK3Z-3 T , was isolated from a branch of Kandelia candel , collected from the Beilun Estuary National Nature Reserve in Guangxi Zhang Autonomous Region, PR China, and investigated by a polyphasic approach to determine its taxonomic position. Strain CBK3Z-3 T grew at pH 5.0-10.0 (optimum, pH 8.0), 20-37 °C (optimum, 25-30 °C) and with 0-10 % (w/v) NaCl (optimum, 2-3 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain CBK3Z-3 T was closely related to species of genus Stakelama and had the highest 16S rRNA gene sequence similarity of 98.7 % to Stakelama pacifica CGMCC 1.7294 T . The DNA G+C content value of strain CBK3Z-3 T was 62.6 mol%. The diagnostic diamino acid in the cell-wall peptidoglycan was meso -diaminopimelic acid and the polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid, an unidentified aminolipid and an unidentified lipid. The major fatty acids were C 18 : 1  ω 7 c and C 16 : 0 . The average nucleotide identity, estimated digital DNA-DNA hybridization and average amino acid identity values between strain CBK3Z-3 T and the type strain of Stakelama pacifica CGMCC 1.7294 T were 80.4, 23.1 and 81.5 %, respectively. Based on the phylogenetic, phenotypic and chemotaxonomic data, strain CBK3Z-3 T should be designated as a novel species of the genus Stakelama , for which the name Stakelama flava sp.nov. is proposed. The type strain is CBK3Z-3 T (=JCM 34534 T =CGMCC 1.18972 T ).

A new polychiral bisabolane sesquiterpene, bisabolanoic acid A ( 1 ), was isolated from the mangrove-derived fungus Colletotrichum sp. SCSIO KcB3-2. Its planar structure was identified on the basis of spectroscopic data analysis (HRESIMS, 1D, and 2D NMR), and the absolute configurations of three chiral carbons were determined by experimental and calculated electronic circular dichroism (ECD) and optical rotatory dispersion (ORD), together with Mo 2 (OAc) 4 -induced ECD methods. Bisabolanoic acid A ( 1 ) showed moderate inhibitory activity against acetylcholinesterase (AChE) with IC 50 value of 2.2 μM, and the in silico molecular docking was also performed.

Three new meroterpenoid derivatives, furanocochlioquinol (1) and furanocochlioquinone (2), as well as nectrianolin D (3), together with two known biogenetically related compounds 4 and 5 were isolated from a mixed culture of two mangrove-derived fungi, Clonostachys rosea B5-2 and Nectria pseudotrichia B69-1. The structures of 1-3 were deduced based on the interpretation of HRMS and NMR data. Compounds 1-5 exhibited cytotoxicity against human promyelocytic leukemia (HL60) cells with IC 50 values ranging from 0.47 to 10.16 μM., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Three unusual austins-type meroterpenoids penicianstinoids C-E ( 1 - 3 ) were obtained from the mangrove-derived fungus Penicillium sp. TGM112. The structures of 1 - 3 including absolute configurations were determined by detailed NMR, MS spectroscopic data, X-ray diffraction analysis, and calculated electronic circular dichroism data. Penicianstinoid C ( 1 ) was the first austins-type meroterpenoid with a unique 6/6/6/5 rearranged tetracyclic skeleton possessing two unusual spirocyclic moieties (2-oxaspiro[5.5]undeca-4,7-dien-3-one and 6-methylene-2-oxaspiro[4.5]decane-1,4-dione). Penicianstinoid D ( 2 ) was an unusual austins-type meroterpenoid with a 6/6/6/6 tetracyclic skeleton containing an octahydro-2 H -chromen-2-one unit. Penicianstinoid E ( 3 ) possessed a 6/5/6/6/6/5 fused hexacyclic skeleton with an uncommon five-membered ether ring system. The plausible biosynthetic pathway of 1 - 3 is also proposed. Compounds 1 and 3 inhibited the growth of newly hatched Helicoverpa armigera Hubner larvae with IC 50 values of 100 and 200 μg/mL, respectively.

Marine derived fungus has gained increasing ground in the discovery of novel lead compounds with potent biological activities including anti-inflammation. Here, we first report the characterization of one new sorbicillinoid (1) and fourteen known compounds (2-15) from the ethyl acetate (AcOEt) extract of a cultured mangrove derived fungus Penicillium sp. DM815 by UV, IR, HR ESI-Q-TOF MS, and NMR spectra. We then evaluated the anti-inflammatory effects of eleven sorbicillinoids (1-11) using cultured macrophage RAW264.7 cells. The results show that compound 9, and to a lesser degree compound 5, significantly inhibited the Gram-negative bacteria lipopolysaccharide (LPS)-induced upregulation of the inducible nitric oxide synthase (iNOS). Consistently, compounds 5 and 9 significantly reduced the level of nitric oxide (NO), the product of iNOS, induced by LPS. We further show that these two compounds dose-dependently inhibited LPS-triggered iNOS expression and NO production, but had no effect on proliferation of RAW264.7 cells in the presence of LPS. In conclusion, our study identifies novel and known sorbicillinoids as potent anti-inflammatory agents, holding the promise of developing novel anti-inflammation treatment in the future., (© 2021 Wiley-VHCA AG, Zurich, Switzerland.)

Four new chromones, phomochromenones D-G ( 1 - 4 ), along with four known analogues, diaporchromone A ( 5 ), diaporchromanone C ( 6 ), diaporchromanone D ( 7 ), and phomochromenone C ( 8 ), were isolated from the culture of Phomopsis asparagi DHS-48 from Chinese mangrove Rhizophora mangle . Their structures were elucidated on the basis of comprehensive spectroscopic analysis. The absolute configurations of 1 and 4 were assigned on the basis of experimental and calculated electronic circular dichroism (ECD) data, and those of enantiomers 2 and 3 were determined by a modified Mosher's method and basic hydrolysis. To the best of our knowledge, phomochromenones D-F ( 1 - 4 ) possessing a 3-substituted-chroman-4-one skeleton are rarely found in natural sources. Diaporchromone A ( 5 ) showed moderate to weak immunosuppressive activity against T and/or B lymphocyte cells with IC 50 of 34 μM and 117 μM.

Mangroves are intertidal extreme environments with rich microbial communities. Actinobacteria are well known for producing antibiotics. The search for biosynthetic potential of Actinobacteria from mangrove environments could provide more possibilities for useful secondary metabolites. In this study, whole genome sequencing and MS/MS analysis were used to explore the secondary metabolite production potential of one actinobacterial strain of Streptomyces olivaceus sp., isolated from a mangrove in Macau, China. The results showed that a total of 105 gene clusters were found in the genome of S. olivaceus sp., and 53 known secondary metabolites, including bioactive compounds, peptides, and other products, were predicted by genome mining. There were 28 secondary metabolites classified as antibiotics, which were not previously known from S. olivaceus. ISP medium 2 was then used to ferment the S. olivaceus sp. to determine which predicted secondary metabolite could be truly produced. The chemical analysis revealed that ectoine, melanin, and the antibiotic of validamycin A could be observed in the fermentation broth. This was the first observation that these three compounds can be produced by a strain of S. olivaceus . Therefore, it can be concluded that Actinobacteria isolated from the mangrove environment have unknown potential to produce bioactive secondary metabolites.

Strain BGMRC 2036 T was isolated from rhizosphere soil of Bruguiear gymnorrhiza collected from the Beibu Gulf of China. Optimum growth occurred at 28 °C, pH 7.0, and under the conditions of 3-5% (w/v) NaCl. The phylogenetic comparisons of 16S rRNA gene sequences displayed that strain BGMRC 2036 T was closely related to Martelella limonii NBRC109441 T (96.6% sequence similarity), M. mediterranea CGMCC 1.12224 T (96.5%), M. lutilitoris GH2-6 T (96.5%), M. radicis BM5-7 T (96.2%), and M. mangrove BM9-1 T (95.9%), M. suaedae NBRC109440 T (95.8%). The phylogenomic tree based on the up-to-date bacterial core gene set indicated that the strain BGMRC 2036 T form a clade formed with members of the genera Martelella. The major polar lipids include phosphatidylmethylethanolamine, phosphatidylglycerol, phosphatidylcholine, phosphotidylinositol, two unidentified phospholipids, and three unidentified ninhydrin positive phospholipids. The major respiratory quinone is Q-10, which is similar to those of genera Martelella. The main cellular fatty acids are C 18:1 ω7c, C 16:0 , and C 12:0 aldehyde. Genome sequencing revealed a genome size of 4.99 Mbp and a G + C content of 62.3 mol%. Pairwise comparison of the genomes of the new strain BGMRC 2036 T and the three reference strains M. endophytica YC 6887 T , M. mediterranea CGMCC 1.12224 T , and M. mangrovi USBA-857 indicated that gANI value was lower than 81% and a digital DNA-DNA hybridization value was lower than 27%. The strain BGMRC 2036 T possessed genes putatively encoding riboflavin synthesis and flavodoxin A polyphasic taxonomic study suggested that strain BGMRC 2036 T represented a novel species belonging to the genus Martelella, and it was named Martelella alba sp. nov. The type strain is BGMRC 2036 T (=KCTC 52121 T  =NBRC 111908 T ).

Chemical investigation of endophytic fungus Phyllosticta capitalensis , isolated from the hypocotyls of the Chinese mangrove Bruguiera sexangula led to the isolation of eight known secondary metabolites, including four meroterpenes guignardone A ( 1 ), 12-hydroxylated guignardone A ( 2 ), guignardone J ( 3 ), guignardone M ( 4 ), and four polyketides xenofuranone B ( 5 ), 6,8-dihydroxy-5-methoxy-3-methyl-1 H -isochromen-1-one ( 6 ), regiolone ( 7 ), 3,4-dihydroxybenzoic acid ( 8 ). Their structures were elucidated unambiguously based on the comprehensive spectroscopic analysis and comparison with literature data. This is the first report of these compounds being isolated from this fungal species. All compounds isolated were subjected to antimicrobial and cytotoxic activities evaluation.

Two new naphthoquinone derivatives, 6-hydroxy-astropaquinone B ( 1 ) and astropaquinone D ( 2 ) as well as the known compound 3- O -methyl-9- O -methylfusarubin ( 3 ) were isolated from Fusarium napiforme , an endophytic fungus isolated from the mangrove plant, Rhizophora mucronata . The structures of 1 and 2 were determined by 1D and 2D NMR spectroscopic analyses. Compounds 1 , 2 and 3 exhibited moderate antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa . Furthermore, 1 , 2 and 3 were phytotoxic action in lettuce seeding at a concentration of 30 μg · mL -1 .

We isolated a novel strain, R1DC25 T , described as Kaustia mangrovi gen. nov. sp. nov. from the sediments of a mangrove forest on the coast of the Red Sea in Saudi Arabia. This isolate is a moderately halophilic, aerobic/facultatively anaerobic Gram-stain-negative bacterium showing optimum growth at between 30 and 40 °C, at a pH of 8.5 and with 3-5 % NaCl. The genome of R1DC25 T comprises a circular chromosome that is 4 630 536 bp in length, with a DNA G+C content of 67.3 mol%. Phylogenetic analyses based on the 16S rRNA gene sequence and whole-genome multilocus sequence analysis of 120 concatenated single-copy genes revealed that R1DC25 T represents a distinct lineage within the family Parvibaculaceae in the order Rhizobiales within the class Alphaproteobacteria . R1DC25 T showing 95.8, 95.3 and 94.5 % 16S rRNA gene sequence identity with Rhodoligotrophos appendicifer , Rhodoligotrophos jinshengii and Rhodoligotrophos defluvii , respectively. The predominant quinone was Q-10, and the polar lipids were phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, as well as several distinct aminolipids and lipids. The predominant cellular fatty acids were C 19 : 0 cyclo ω 8 c , a combination of C 18 : 1 ω 7 c and/or C 18 : 1 ω 6 c and C 16 : 0 . On the basis of the differences in the phenotypic, physiological and biochemical characteristics from its known relatives and the results of our phylogenetic analyses, R1DC25 T (=KCTC 72348 T ;=JCM 33619 T ;=NCCB 100699 T ) is proposed to represent a novel species in a novel genus, and we propose the name Kaustia mangrovi gen. nov., sp. nov. ( Kaustia, subjective name derived from the abbreviation KAUST for King Abdullah University of Science and Technology; mangrovi , of a mangrove).

A Gram-stain-positive, aerobic, non-motile, non-endospore-forming and rod-shaped actinobacterium, designated strain CMS6Z-2 T , was isolated from a surface-sterilized branch of Kandelia candel collected from the Maowei Sea, Guangxi Zhuang Autonomous Region, PR China. Strain CMS6Z-2 T grew at 10-37 °C (optimum, 37 °C), pH 6.0-9.0 (optimum, pH 7.0-8.0) and in the presence of 0-10.0 % (w/v) NaCl (optimum, 0-1.0 %). Strain CMS6Z-2 T possessed meso -diaminopimelic acid as the diamino acid of the peptidoglycan and MK-8 (H 4 ) as the predominant menaquinone. The major fatty acids were iso-C 15 : 0 , C 16 : 0 and C 18 : 1  ω 9 c . The polar lipids comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and two unknown phospholipids. The G+C content of the genomic DNA was 74.1 mol%. Comparative analysis of 16S rRNA genes showed that strain CMS6Z-2 T should be assigned to the genus Phycicoccus and its closest relative was Phycicoccus endophyticus IP6SC6 T with 98.3 % similarity. Phylogenetic analyses based on 16S rRNA gene sequence and phylogenomic analysis based on core proteomes alignment revealed that strain CMS6Z-2 T belonged to the genus Phycicoccus and formed a robust cluster with Phycicoccus endophyticus IP6SC6 T within the genus Phycicoccus . The average nucleotide identity value and estimated digital DNA-DNA hybridization value between strain CMS6Z-2 T and the type strain of Phycicoccus endophyticus were 81.5 and 23.9 %, respectively. On the basis of phylogenetic, phenotypic and chemotaxonomic characteristics, strain CMS6Z-2 T represents a novel species of the genus Phycicoccus , for which the name Phycicoccus flavus sp. nov. is proposed. The type strain is CMS6Z-2 T (=KCTC 49240 T =CGMCC4.7549 T ).

Seven new compounds including five aromatic butenolide analogues (1-5), one quinazolinone alkaloid (6) and one benzoic acid derivative (7), along with eleven known co-metabolites (8-18), were isolated from Aspergillus terreus SCAU011, a fungus from the rhizosphere sediment of a mangrove plant Rhizophora stylosa. The structures of these isolates were established by a combination of MS, NMR and ECD data analyses, as well as chemical method. Compound 3 is a rare ring-open aromatic butenolide, while 6 represents the first natural ring-open benzomalvin-type quinazolinone alkaloid. Also, the previously reported structures for asperlides A-C were proposed to be revised in the present work. The COX-2 inhibitory, α-glucosidase inhibitory, antioxidant and antibacterial activities of all the compounds were assessed. While compounds 4, 6, 11 and 18 exhibited better COX-2 inhibitory activity than the positive control celecoxib, compounds 9 and 10 showed significant α-glucosidase inhibitory activity with IC 50 values of 56.1 and 12.9 μM, respectively. Meanwhile, half of the tested samples (1, 8-11 and 15-17) exerted similar or better antioxidant activity compared with the reference drug curcumin, and compounds 3, 9, 17 and 18 displayed moderate antibacterial effect against Staphylococcus aureus., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Four new cyclohexene derivatives cladoscyclitols A-D (1-4) and one new ribofuranose phenol derivative 4-O-α-D-ribofuranose-2-pentyl-3-phemethylol (5) were obtained from the EtOAC extract of the mangrove-derived endophytic fungus Cladosporium sp. JJM22. The structures were elucidated by extensive NMR and MS analysis, while the absolute configurations of the stereogenic carbons were established based on quantum-chemical electronic circular dichroism calculations or comparison of the optical rotations with those of related compounds. Compounds 2 and 5 displayed potent inhibitory activity against α-glucosidase with the IC 50 values of 2.95 and 2.05 μM, respectively., (Copyright © 2021 Elsevier B.V. All rights reserved.)

One new chromanone derivative, alterchromanone A (1), and four known curvularin-type macrolides (2-5) were isolated from the crude extract of the mangrove-derived endophytic fungus Alternaria longipes. Their structures were elucidated by MS and NMR spectroscopic analyses and by a comparison with data from the literature. The absolute configuration of 1 was assigned by combination of experimental and calculated electronic circular dichroism (ECD) spectra. Compound 1 exhibited 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity with an IC 50 value of 56.3 μg ml -1 . According to the structural features of these compounds, the plausible biosynthetic pathways of 1-5 were also proposed.

Cadinanes are typical plant sesquiterpenes with a broad range of biological functions. We report the isolation of three cadinanes (1-3) from a bacterial endophyte (Streptomyces sp.) of the mangrove plant Bruguiera gymnorrhiza. The structures of two new cadinenes, (+)-11-hydroxy-epicubenol (1) and (+)-12-hydroxy-epicubenol (2) were elucidated by nuclear magnetic resonance (NMR) and mass spectrometry. The bacterial product (+)-11-hydroxy-epicubenol was elucidated to be an enantiomer of the plant product pubinernoid C. (+)-12-Hydroxy-epicubenol was established as a diastereomer of the basidiomycete product trichapargin A. In addition, a crystal structure analysis corroborated the structure and configuration of 5,11-epoxy-10-cadinanol (3), a cadinane cycloether initially described as a natural product from liverwort. The discovery of oxygenated cadinanes from a bacterial endophyte may set the basis for the production of cadinanes by bacterial fermentation., (© 2020 John Wiley & Sons, Ltd.)

Worldwide cancer incidence and mortality have always been a concern to the community. The cancer mortality rate has generally declined over the years; however, there is still an increased mortality rate in poorer countries that receives considerable attention from healthcare professionals. This suggested the importance of the prompt detection, effective treatment, and prevention strategies. The genus Streptomyces has been documented as a prolific producer of biologically active secondary metabolites. Streptomycetes from mangrove environments attract researchers' attention due to their ability to synthesize diverse, interesting bioactive metabolites. The present review highlights research on mangrove-derived streptomycetes and the production of anticancer-related compounds from these microorganisms. Research studies conducted between 2008 and 2019, specifically mentioning the isolation of streptomycetes from mangrove areas and described the successful purification of compound(s) or generation of crude extracts with cytotoxic activity against human cancer cell lines, were compiled in this review. It is anticipated that there will be an increase in prospects for mangrove-derived streptomycetes as one of the natural resources for the isolation of chemotherapeutic agents.

A novel, Gram-stain-positive, aerobic, non-spore-forming, non-motile and irregular rod-shaped bacterium designated Q22 T was isolated from the rhizosphere soil of mangrove plant, Kandelia candel collected in Zhangzhou, Fujian province, China. Strain Q22 T was able to grow at 10-40 °C (optimum 30 °C), pH 5.5-9.0 (optimum 7.0-8.0) and with 0-5.0% (w/v) NaCl (optimum 1.0 %). The genomic DNA G+C content was 71.9%. The average nucleotide identity, and in silico DNA-DNA hybridization values between strain Q22 T and the reference strains were 79.7-88.9% and 22.6-37.4%, respectively. The predominant isoprenoid quinone was MK-12 and the major fatty acids were anteis o-C 15:0 , iso -C 16:0 and anteiso -C 17:0 . The major polar lipids of strain Q22 T were diphosphatidylglycerol, phosphatidylglycerol, one glycolipid and three unidentified lipids. The strain Q22 T contained 2,4-diaminobutyric acid, alanine acid, glutamic acid and glycine in the peptidoglycans. The phylogenetic analysis and genotypic features, along with the phenotypic and chemotaxonomic characteristics, indicate that strain Q22 T represents a novel species of the genus Agromyces , for which the name Agromyces kandeliae sp. nov. is proposed. The type strain is Q22 T (=MCCC 1K03340 T = KCTC 39961 T ).

Two new compounds, triacremoniate (1) and dietziamide C (2) along with known compounds β-Adenosine (3) and acrepyrone A (4) were obtained from the mangrove-derived fungus Acremonium citrinum. MMF4. Their structures were unambiguously determined by extensive spectroscopic methods, including UV, IR, HRESIMS and NMR. Triacremoniate (1) can promote apoptosis of HeLa cells by increasing the PARP cleavage and the phosphorylation of JNK and p38., (Copyright © 2020. Published by Elsevier B.V.)

A novel Gram-stain negative, aerobic, non-motile, rod-shaped bacterium, designated as strain EB310 T , was isolated from rhizosphere soil of mangrove plant Kandelia candel in Fugong village, Zhangzhou, China. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain EB310 T belonged to the genus Erythrobacter, clustering with Erythrobacter pelagi JCM 17468 T , Erythrobacter lutimaris KCTC 42109 T and Erythrobacter marisflavi KCTC 62896 T , and showed the highest 16S rRNA gene sequence similarity of 97.5% to Erythrobacter pelagi JCM 17468 T . The genomic average nucleotide identity and in silico DNA-DNA hybridization values between strain EB310 T and the reference strains were 71.0-75.5% and 19.8-20.0%, respectively. Growth ranges of the isolate occurred at 10-45 °C (optimum 28-30 °C), pH 5.5-9.5 (optimum pH 7.5) and 0-9.0% NaCl concentrations (optimum 2.0%, w/v). The strain did not produce bacteriochlorophyll a and flexirubin, but produced carotenoids. The strain contained Q-10 as the predominant ubiquinone and summed feature 3 (C 16:1 ω7c/C 16:1 ω6c) and summed feature 8 (C 18:1 ω6c/C 18:1 ω7c) as the major fatty acids. The major polar lipids were sphingoglycolipid, phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylcholine. Differential phenotypic characteristics, together with chemotaxonomic, phylogenetic and genomic distinctiveness, indicated that strain EB310 T is distinguishable from other members of the genus Erythrobacter. On the basis of the data exhibited, strain EB310 T is considered to represent a novel species of the genus Erythrobacter, for which the name Erythrobacter mangrovi sp. nov., is proposed. The type strain is EB310 T (= KCTC 72109 T  = MCCC 1K03690 T ). The genomic DNA G + C content is 62.9 mol%.

Mangrove fungi, their ecological role in mangrove ecosystems, their bioproducts, and potential applications are reviewed in this article. Mangrove ecosystems can play an important role in beach protection, accretion promotion, and sheltering coastlines and creeks as barriers against devastating tropical storms and waves, seawater, and air pollution. The ecosystems are characterized by high average and constant temperatures, high salinity, strong winds, and anaerobic muddy soil. The mangrove ecosystems also provide the unique habitats for the colonization of fungi which can produce different kinds of enzymes for industrial uses, recycling of plants and animals in the ecosystems, and the degradation of pollutants. Many mangrove ecosystem-associated fungi also can produce exopolysaccharides, Ca 2+ -gluconic acid, polymalate, liamocin, polyunsaturated fatty acids, biofuels, xylitol, enzymes, and bioactive substances, which have many potential applications in the bioenergy, food, agricultural, and pharmaceutical industries. Therefore, mangrove ecosystems are rich bioresources for bioindustries and ecology. It is necessary to identify more mangrove fungi and genetically edit them to produce a distinct array of novel chemical entities, enzymes, and bioactive substances.

A simple but previously undescribed macrolide with unprecedented bicyclo 5/9 ring system, namely, cladocladosin A (1), along with two new sulfur-containing macrolides, namely, thiocladospolides F and G (2 and 3), were characterized from the mangrove-derived endophytic fungus Cladosporium cladosporioides MA-299. The structures of these compounds were established on the basis of spectroscopic interpretation, and the absolute configurations of compounds 1-3 were determined by X-ray crystallographic analysis, Mosher's method, and by a biogenetic point of view. The possible biogenetic pathway for compounds 1-3 as well as their congeners thiocladospolides A-D and pandangolide 3 was proposed, providing a role in distinguishing the position of sulfur substitution in thiomacrolides. Compounds 1-3 were evaluated for antimicrobial activities against human-, aquatic-, and plant-pathogenic microbes., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Chemical examination of Chinese mangrove Ceriops tagal endophytic Cytospora sp., yielded a new biscyclic sesquiterpene seiricardine D ( 1 ), and eight known metabolites, xylariterpenoid A ( 2a ), xylariterpenoid B ( 2b ) and regiolone ( 3 ) 4-hydroxyphenethyl alcohol ( 4 ), (22 E , 24 R )5, 8-epidioxy-5α, 8α-ergosta-6,22 E -dien-3ß-ol ( 5 ), (22 E , 24 R )5, 8-epidioxy-5α, 8α-ergosta-6,9(11), 22-trien-3 ß-ol ( 6 ), ß-sitosterol ( 7 ) and stigmast-4-en-3-one ( 8 ). These structures were unambiguously elucidated on the basis of extensive NMR spectroscopic and mass spectrometric analyses. The antimicrobial activities of compounds 1-8 and their effects on a panel of plant and human pathogens were evaluated.