RESUMEN

A new sterol, aspersterol E (1), a newly discovered alkaloid, asperginine A (2), and five known compounds (3-7) were obtained from the endophytic fungus Aspergillus sp. S3 of Hibiscus tiliaceus Linn. The compounds were extracted from their fermentation products using silica gel, ODS C18, and semi-preparative HPLC. The structure of each compound was determined through spectroscopic analysis. All the obtained compounds (1-7) were evaluated for their cytotoxic activity against the mouse pre-gastric cancer cell line MFC by using the MTT assay. The IC50 values of compounds 1, 2, 3, and 5 were found to be 153.43 µM, 61.25 µM, 73.19 µM, and 181.69 µM respectively.

RESUMEN

OBJECTIVE: There is very limited published experience on mangrove pit viper envenomation in the medical literature. This study aims to analyze the clinical characteristics, treatment modalities and outcomes of patients presenting to Selangor middle zone cluster Hospitals in Malaysia with confirmed mangrove pit viper bites. METHODS: We conducted a retrospective observational study, reviewing medical records of patients treated for mangrove pit viper bites between July 1, 2020 to June 30, 2023. Data on patient demographics, clinical characteristic, laboratory findings, treatment modalities and clinical outcomes were collected and analyzed. RESULTS: A total of 25 patients were included in this study. The majority of the patients were male (n = 23, 92%) with the mean age of 38.7 ± 17.6 years. Most frequent anatomical region involved is foot (n = 12, 48%). Common clinical presentation included localized pain (n = 24, 96%), swelling (n = 22, 88%) and fang mark (n = 22, 88%). Systemic symptoms were less common, with 1 patient exhibiting coagulopathy with clinical bleeding at 28 h post bite. Antivenom was administered to 68% (n = 17) of the patients. The majority of the patients (n = 23, 92%) recovered without significant morbidity while 8% (n = 2) of the patients developed skin infection that required antibiotic therapy. No fatalities were reported. CONCLUSION: Mangrove pit viper envenomation encountered in these regions predominantly causes local symptoms while systemic symptoms were less common. This study provides a glimpse to the clinical characteristics and management of mangrove pit viper envenomation, coagulopathy may be delayed due to characteristic of the snake venom and patient's preexisting illness. Further research is needed to enhance our understanding of this snakebite envenomation.

Asunto(s)

RESUMEN

The effects of endogenous mangrove litterfall (MF) inputs on organic matter transformation in sediment polluted by exogenous microplastics (MPs) were investigated in this work, and their linkage with microbial characteristics was also explored. MF inputs significantly affected organic carbon transformation in MPs-polluted sediment by improving humification, enzymatic activities and carbon utilisation capacity of microbes. Such effects were mainly linked with the enrichment of microbes responsible for organic substance decomposition induced by MF inputs. Indeed, MF addition increased the relative abundance of fermentation- and cellulysis-assoicated bacteria, together with Saprotrophic fungi. Moreover, dissolved matters derived from MF played a non-neglected role in regulating organic carbon transformation in MPs-polluted sediment. Besides, MF addition decreased the complexity of bacterial community network in MPs-polluted sediment but fungal community network became complicated. And the complexity of microbial network was MF amount-dependent. Even though stochastic process was dominated in sediment with or without MF, MF inputs enhanced the relative contribution of determinism and reduced the migration of microbial communities. A strong response of sediment microbes to MF affected sedimentary organic matters transformation driven by microbes. This work uncovered linkages between organic carbon transformation and microbes in sediment with endogenous litterfall and exogenous MPs inputs in mangroves.

RESUMEN

Cadmium (Cd) pollution has gained significant attention in mangrove sediments due to its high toxicity and mobility. However, the sources of Cd and the factors influencing its accumulation in these sediments have remained elusive. In this study, we utilized lead (Pb) isotopic signatures for the first time to assess Cd contamination in mangrove sediments from the northern region of the Beibu Gulf. A strong correlation was observed between Cd and Pb concentrations in the mangrove sediments, suggesting a shared source that can be estimated using Pb isotopic signatures. By employing a Bayesian mixing model, we determined that 70.1 ± 8.2 % of Cd originated from natural sources, while 12.9 ± 4.9 %, 9.8 ± 3.7 %, and 7.1 ± 3.4 % were attributed to agricultural activities, non-ferrous metal smelting, and coal combustion, respectively. Our study clearly suggests that natural Cd could also dominate the high Cd content. Agricultural activities were the most important anthropogenic Cd sources, and the increased anthropogenic Cd accumulation in mangrove sediment was related to organic matter. This study introduces a novel approach for assessing Cd contamination in mangrove sediment, providing useful insights into Cd pollution in coastal wetlands.

RESUMEN

Endophytic fungi are useful in a variety of biological processes and may find value in pharmaceutical settings. However, there hasn't been much research done on the bioactive compounds produced by mangrove fungal endophytes from the East African coast. Our previous research revealed a significant number of mangrove endophytic fungi in Dar es Salaam, Tanzania. This study explores the antimicrobial and cytotoxic properties of these endophytic fungi. Crude extracts of 34 mangrove endophytic fungal isolates were screened, with thirteen showing antimicrobial activity against tested microorganisms. MIC and cytotoxicity tests revealed varying bioactivity. Aspergillus fumigatus (HMD45) was particularly potent against tested organisms (MIC = <0.195 to 0.391 mg/ml) and (LC50 = 36.001). GC-MS evaluation of HMD45 extracts indicated the existence of compounds including dodecanoic acid, n-heptadecanol-1, and n-hexadecanoic acid, which may contribute to its bioactivity. These findings offer insight into the bioactivity of mangrove endophytic fungi and trigger interest for further research.

RESUMEN

Three previously undescribed pyrrolizidinone alkaloids, penicipyrrolizidinones A and B (1 and 2), possessing an unprecedented 2-methyl-2-(oct-6-enoyl)pyrrolizidin-3-one skeleton, and penicipyrrolizidinone C (3), featuring a rare 1-alkenyl-2-methyl-pyrrolizidin-3,7-dione skeleton, together with four known pyrrolidine derivatives (4-7) were isolated from the mangrove-derived fungus Penicillium sp. DM27. Their structures were elucidated through comprehensive spectroscopic analysis, theoretical calculations of ECD spectra, and the modified Mosher's method. A plausible biosynthetic pathway for penicipyrrolizidinones A-C (1-3) was proposed. Compounds 4 and 5 exhibited moderate cytotoxicity against B16-F10 melanoma cells with IC50 values of 10.5 µM and 15.5 µM, respectively.

RESUMEN

A dimeric citrinin derivative with a unique spiro[chroman-2,3'-isochroman] skeleton, xerucitrinic acid C (1), and a new citrinin derivative, cladosporin E (6), along with ten known polyketides (2-5 and 7-12), were isolated from the mangrove sediment-derived fungus Talaromyces sp. SCSIO 41428. Their structures were elucidated through comprehensive spectral data analysis. The absolute configurations of 1 and 6 were determined by quantum chemical calculations. Compound 1 exhibited significant inhibitory effects on Staphylococcus aureus and Streptococcus suis, with the MIC of 25 µg/mL for both bacterial strains. Xerucitrinin C (3) exhibited significant radical scavenging activity against DPPH, with an IC50 value of 25.4 µM, and also demonstrated inhibitory activity against phosphodiesterase-4 (PDE4). Moreover, cladosporin C (7) notably inhibited prostate cancer cells PC-3 and 22Rv1, with IC50 values of 6.10 and 9.25 µM, respectively.

RESUMEN

Mangrove ecosystems are crucial for protecting littoral regions, preserving biodiversity and sequestering carbon. The implementation of effective conservation and management strategies requires a comprehensive understanding of mangrove community structure, canopy coverage and overall health. This investigation focused on four small islands located within the Bunaken National Park in Indonesia: Bunaken, Manado Tua, Mantehage and Nain. Utilising the line transect quadrant method and hemispherical photography, the investigation comprised a total of 12 observation stations. Nain had the greatest average canopy coverage at 76.09%, followed by Mantehage, Manado Tua and Bunaken at 75.82%, 71.83% and 70.01%, respectively. Mantehage had the maximum species density, with 770.83 ind/ha, followed by Bunaken, Nain and Manado Tua with 675 ind/ha, 616.67 ind/ha and 483.34 ind/ha, respectively. The predominant sediment type observed was sandy mud and the mangrove species identified were Avicennia officinalis (AO), Bruguiera gymnorrhiza (BG), Rhizophora apiculata (RA), R. mucronata (RM), and Sonneratia alba (SA). On the small islands, S. alba emerged as the dominant mangrove species based on the importance value index (IVI). In addition, the Mangrove Health Index revealed that only 6.79% of the region exhibited poor health values, while 50% of the region was categorised as being in outstanding condition. These findings indicate that the overall condition of mangroves on these islands was relatively favourable.

RESUMEN

Mineral-organic matter-microbe interactions greatly impact the biogeochemical processes and biodiversity in soils. An increasing trend of particle size (PS) in mangrove soils has been observed because of the relative sea level rise. However, the impacts of PS increase on the microbial biogeochemical functions and carbon sink in the mineral-associated microcosms are exceedingly nebulous. This work showed a remarkable difference in the communities of mineral-associated microorganisms (MMOs) in various PS fractions. Heavy metal contents and urease activity were the factors that mostly driven the MMO community variation in different PS fractions. Large PS fraction attenuated the stability of MMO communities according to the co-occurrence network characteristics. The PS increase significantly (P < 0.05) lowered the gene abundances for carbon input (e.g., carbon fixation) and raised the gene abundances for carbon loss (e.g., aerobic respiration). Combined with the significant decrease of mineral-associated organic carbon (MOC) in large PS fraction (P < 0.05), this work inferred that the PS increase could weaken the MOC sink partially due to the MMO function shift for carbon cycle. The current work indicated unhealthy changes of MMO communities and MOC storage in mangrove soils, and PS was of significance as an indicator for predicting the carbon sink function, especially for the stable form, such as MOC, in the soils of mangroves under the ecological background of climate migration. IMPORTANCE: Carbon with stable forms, such as mineral-associated organic carbon (MOC), is crucial for the sink capabilities in mangrove soils, and mineral-associated microorganisms (MMOs) are important players for the formation and metabolism of MOC. Therefore, the future successions of the MMO functions and MOC contents under the background of climate change are of value for a deeper understanding of mangrove ecology. The relative sea level rise caused by the global warming results in the increase of mangrove soil particle size (PS), which provides distinct microcosms for MMOs and MOC. However, the responses of MMO functions and MOC content to the PS increase of mangrove soils are unknown. The current study aims to reveal the succession regulations of MMO functions and their potential ecological impacts for the storages of MOC in different PS fractions, therefore widening our knowledge of future function migration and promoting the research development of mangrove.

RESUMEN

Considerable amounts of microplastics (MPs) are stocked in plant rhizospheres, yielding adverse effects on rhizospheric microorganisms and threatening plant health. However, the adaptation of the rhizospheric microbiota for MPs remains largely unknown. Here, to evaluate the adaptive strategies of rhizospheric bacterial communities against MPs, we characterized the spatial dissimilarities in MPs properties and bacterial communities from mangrove non-rhizosphere to rhizosphere to root hair sediments. Consequently, two strategies were uncovered: (1) Bacterial communities showed significant niche differentiation induced by the increasingly enriched MPs evaluated by piecewise structural equation modeling (piecewise SEM), as increasing specialization (10.2 % to 19.4 % to 23.0 % of specialists) and decreasing generalization (10.4 % to 10.2 % to 8.7 % of generalists). (2) A self-remediation strategy of enhancing microbial plastic-degrading potentials was determined in bacterial communities, tightly coupled to the increase of specialists (linear regression analysis, R2 = 0.54, P < 0.001) and increasing MPs weathering degrees visualized by the scanning electron microscopy (SEM) from non-rhizosphere to rhizosphere to root hair regions. Our study provides a novel insight into the ecological strategies that rhizospheric microbes utilize against MPs, and broadens our knowledge of the interaction between soil microbes and global MPs pollution.

RESUMEN

Unraveling the geochemical and microbial controls on methylmercury (MeHg) dynamics in mangrove sediments is important, as MeHg can potentially pose risks to marine biota and people that rely on these ecosystems. While the important role of sulfate-reducing bacteria in MeHg formation has been examined in this ecologically important habitat, the contribution of non-Hg methylating communities on MeHg production remains particularly unclear. Here, we collected sediment samples from 13 mangrove forests in south China and examined the geochemical parameters and microbial communities related to the Hg methylation. MeHg concentrations were significantly correlated to the OM-related parameters such as organic carbon content, total nitrogen, and dissolved organic carbon concentrations, suggesting the importance of OM in the MeHg production. Sulfate-reducing bacteria were the major Hg-methylators in mangrove sediments. Desulfobacteraceae and Desulfobulbaceae dominated the Hg-methylating microbes. Classification random forest analysis detected strong co-occurrence between Hg methylators and putative non-Hg methylators, thus suggesting that both types of microorganisms contribute to the MeHg dynamics in the sediments. Our study provides an overview of MeHg contamination in south China and advances our understanding of Hg methylation in mangrove ecosystems.

RESUMEN

Pentatricopeptide repeat (PPR) gene family constitutes one of the largest gene families in plants, which mainly participate in RNA editing and RNA splicing of organellar RNAs, thereby affecting the organellar development. Recently, some evidence elucidated the important roles of PPR proteins in the albino process of plant leaves. However, the functions of PPR genes in the woody mangrove species have not been investigated. In this study, using a typical true mangrove Kandelia obovata, we systematically identified 298 PPR genes and characterized their general features and physicochemical properties, including evolutionary relationships, the subcellular localization, PPR motif type, the number of introns and PPR motifs, and isoelectric point, and so forth. Furthermore, we combined genome-wide association studies (GWAS) and transcriptome analysis to identify the genetic architecture and potential PPR genes associated with propagule leaves colour variations of K. obovata. As a result, we prioritized 16 PPR genes related to the albino phenotype using different strategies, including differentially expressed genes analysis and genetic diversity analysis. Further analysis discovered two genes of interest, namely Maker00002998 (PLS-type) and Maker00003187 (P-type), which were differentially expressed genes and causal genes detected by GWAS analysis. Moreover, we successfully predicted downstream target chloroplast genes (rps14, rpoC1 and rpoC2) bound by Maker00002998 PPR proteins. The experimental verification of RNA editing sites of rps14, rpoC1, and rpoC2 in our previous study and the verification of interaction between Maker00002998 and rps14 transcript using in vitro RNA pull-down assays revealed that Maker00002998 PPR protein might be involved in the post-transcriptional process of chloroplast genes. Our result provides new insights into the roles of PPR genes in the albinism mechanism of K. obovata propagule leaves.

RESUMEN

Wetlands provide resources, regulate the environment, and stabilize shorelines; however, they are among the most vulnerable ecosystems in the world. The classification of mangrove species allows the determination of the habitat of each species, thereby serving as a basis for determining protection solutions and planning plans for mangrove conservation and restoration according to each environmental condition. We used Phantom 4 multispectral unmanned aerial vehicles (UAVs) to collect data from wetland areas in the Dong Rui Commune, which is one of the most diverse and valuable wetland ecosystems in northern Vietnam. A tree-species classification map was constructed through a combination of the object-based image analysis method and spectral reflectance values of each plant species, and the characteristic distributions of mangrove plants, including Bruguiera gymnorrhiza, Rhizophora stylosa, and Kandelia obovata, were determined with an overall accuracy of 91.11 % and a kappa coefficient (K) of 0.87. The overall accuracy for Rhizophora stylosa was the highest (94.23 %), followed by Kandelia obovata (93.61 %) and Bruguiera gymnorrhiza (85.50 %). An experiment was conducted to map plant taxonomy in the same area based only on a graph of spectral reflectance values at five single-spectral bands, and normalized difference vegetation index values were constructed, resulting in an overall accuracy of 78.22 % and a K of 0.67. The constructed map is useful for classifying, monitoring, and evaluating the structure of each group of mangroves, thereby serving as a basis for determining the distribution of each mangrove species according to natural conditions and contributing to the formulation of policies for afforestation and mangrove conservation in Dong Rui commune.

RESUMEN

Due to the combined influences of marine and terrestrial disturbances, the sources of microplastics (MPs) in mangrove ecosystems are complex and diverse. Previous studies have inferred the possible involvement of mariculture activities as a potential source of mangrove MPs based on the characteristics of MPs. However, the direct contributions of mariculture-derived MPs to mangrove MPs remain largely unknown. In this study, we systematically investigated the fate of MPs in the discharge of mariculture wastewater by quantifying the source contributions of mariculture-derived MPs to rivers and mangroves. The majority of detected MPs were transparent fibers, with their composition primarily comprising materials commonly used in mariculture activities such as polyvinylpyrrolidone (PVP), polyethylene terephthalate (PET), and nylon. The partial least squares path model elucidated the relationships among the composition of MPs in ponds, rivers, and mangroves, indicating that ponds exert a substantial direct effect on mangroves, particularly significant in the sediments (63.68%). Water turbidity, sediment carbon content, and sediment particle size are key ecological factors influencing the abundance of mariculture-derived MPs. This study provides compelling evidence regarding the sources of mangrove MPs and novel insights into mitigating the dissemination of MPs.

RESUMEN

Asperphenol A (1), a new isoprenyl-phenol-type meroterpenoid, was isolated from the mangrove endophytic fungus Aspergillus sp. GXNU-Y65 together with five known compounds (2-6). All structures were assigned using extensive NMR spectroscopic data and electronic circular dichroism (ECD) calculations. Compounds 1-6 were evaluated for their cytotoxic activity against A549 and T24 human cancer cell lines. Among them, compounds 1 and 5 exhibited moderate inhibitory activities against T24 cancer cell lines with the IC50 values of 26.71 and 43.50 µM, respectively.

RESUMEN

Wetlands are widely regarded as biogeochemical hotspots of mercury methylation but little is known regarding such roles of mangrove forests. Here, we examined the detailed depth profile of mercury, methylmercury, and organic matter in surface sediments within an estuarine pond at Mai Po Nature Reserve in Hong Kong, China. There is a progressive enrichment of organic matter in sites closer to mangrove forests, and methylmercury showed a significantly positive correlation with organic matter content (p < 0.001). Methylmercury in sediments is significantly (p < 0.05) higher in the summertime when the temperature is elevated but salinity is reduced. Further, sediments at or near the mangrove forest have lower carbon to nitrogen ratio, which may imply more labile organic matter in these organic-rich sediments that can promote microbial mercury methylation. In summary, mangrove forests can enhance net methylmercury production and increase the risk to the migratory birds overwintering in this internationally important wetland.

Asunto(s)

RESUMEN

Microplastic ingestion by marine organisms presents a challenge to both ecosystem functioning and human health. We characterized microplastic abundance, shape, size, and polymer types ingested by the West African mangrove oyster, Crassostrea tulipa (Lamarck, 1819) sampled from estuaries and lagoons from the Gambia, Sierra Leone, Ghana, Benin, and Nigeria using optical microscopy and Fourier transform infrared (FTIR) techniques. A total of 780 microplastics were isolated in the whole tissues of the 250 oysters (n = 50 oysters per country). The abundance and distribution of microplastics in the oysters followed the pattern: the Gambia > Ghana > Sierra Leone > Nigeria > Benin. The Tanbi wetlands in the Gambia recorded the highest average of 10.50 ± 6.69 per oyster while the Ouidah lagoon in Benin recorded the lowest average of 1.80 ± 1.90 per oyster. Overall, microplastic numbers varied significantly (p < 0.05) among the five countries. Microfibers, particularly those within 1001-5000 µm size, dominated the total microplastic count with a few fragments and films. No spherical microplastics were isolated in the oysters. In the Sierra Leone and Benin oysters, fragments and films were absent in the samples. Microplastic between the 1001 and 5000 µm size class dominated the counts, followed by 501-1000 µm, 101-500 µm, and 51-100 µm. Five polymer groups namely polyethylene, polyester, nylon, polypropylene, and polyamide were identified across the five countries, with polyethylene occurring in oysters from all five countries and polyester occurring in all but the oysters from Nigeria. This diversity of polymers suggests varied sources of microplastics ingested by the studied oysters. The absence of microspheres across the five supports findings from other studies that they are the least ingested and highly egested by the oysters.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

This study examined effects of mangrove plants Kandelia obovata and Aegiceras corniculatum on harmful algal species. While A. corniculatum leaf extract had no inhibitory effect, K. obovata leaf extract significantly inhibited the growth of two harmful algal species Alexandrium tamarense and Karenia mikimotoi. The inhibitory effect was concentration-dependent, with over 90 % inhibition at the highest concentration. Morphological changes and cell size reduction were observed in both microalgae. Excessive production of reactive oxygen species and damage to algal photosynthetic system were found. The allelopathic effect of K. obovata on K. mikimotoi with low-concentration repeated exposure was more effective than high-concentration single exposure. The EC50 of K. obovata (0.33 g L-1) was lower than reported values on other coastal plants. Higher inhibitory effects of K. obovata were found on naked algal species than the armoured ones. These findings suggest potential applications of K. obovata leaf extract in controlling harmful algal blooms.

Asunto(s)

RESUMEN

The abandoned pond-to-mangrove restoration project provides greater advantages than tidal flats afforestation in restoring mangrove ecosystem services and will be the primary method for mangrove restoration in the future. The existing methods for abandoned pond-to-mangrove restoration include artificial restoration through 'dike-breaking, filling with imported soil and tree planting' and natural restoration through 'dike-breaking and natural succession'. However, little is known about which restoration strategy (natural or artificial restoration) provides more benefits to the biodiversity of mangrove macrobethos. Given a prevailing view suggested that artificial restoration should be the preferred approach for accelerating recovery of biodiversity and vegetation structure in tropical regions, we hypothesised higher macrobenthic biodiversity and more complex community structure in artificial restoration than in natural restoration. To test this hypothesis, macrobenthic biodiversity and ecological processes were monitored in a typical abandoned pond-to-mangrove area of Dongzhaigang Bay, China, where artificial and natural restoration methods were used concurrently. Differences in macrobenthic biodiversity, community structure and ecological processes were compared using diversity indices, complex network analysis and null models. Similar species composition and ecological niche overlap and width among macrobenthos were observed at artificial and natural restoration sites. The biotic heterogeneity and interaction among macrobenthos were higher at the natural restoration sites than at the artificial restoration sites. Macrobenthos community assembly at natural and artificial restoration sites was both determined by deterministic processes, with environmental filtering dominating, which explained 52% and 54% of the variations in macrobenthic community structures respectively. Although our findings did not validate the research hypothesis, higher biotic heterogeneity and species interaction among macrobenthos could support natural restoration as the primary method for abandoned pond-to-mangrove projects, because it is a nature-based solution for mangrove restoration.