Modeling Habitat Suitability for Cerithidea rhizophorarum and Telescopium telescopium in Indo-West Pacific Mangroves.

Mangroves provide habitat for a diverse array of marine species, especially snails. We used a MaxEnt model to predict potential global suitable habitat for Cerithidea rhizophorarum and Telescopium telescopium in the family Potamididae. A total of 667 occurrence data were obtained from the Global Biodiversity Information Facility (GBIF) with the following sub-data set contribution, "iNaturalist Research Grade Observations" (85%), "International Barcode of Life project (iBOL)" (7%), "FBIP: SeaKeys_SANBI: Marine images iSpot_2013" (1%), "A dataset of marine macroinvertebrate diversity from Mozambique and São Tomé and Príncipe" (1%), occurrence data of some marine invertebrates and freshwater crabs housed in the natural history collection at the National Museums of Kenya (1%), and Natural History Museum Rotterdam-Specimens (1%). Our results showed that temperature with a contribution of above 80% in the present and future model is the most important driver of the distribution of mangrove snails. In the present and future models, the most potentially suitable habitats for C. rhizophorarum and T. telescopium were observed along coastal areas with a temperature between 20°C-21°C and 30°C, respectively. Our model predicts that by 2100, high-suitability areas will shrink as a result of global warming. The vulnerability of mangrove snails under future climate conditions is evident in our results. Our findings contribute significant insights into the intricate relationship between mangrove habitats and mangrove snails, offering a valuable foundation for conservation initiatives aimed at safeguarding the biodiversity and ecological functions of these crucial coastal ecosystems in the face of changing global environmental conditions.

Stand age-related effects of mangrove on archaeal methanogenesis in sediments: Community assembly and co-occurrence patterns.

Mangrove sediment is a key source of methane emissions; however, archaea community structure dynamics and methanogenesis activities during long-term mangrove restoration remain unclear. In this study, microcosm incubations revealed a substantial reduction in microbial-mediated methane production potential from mangrove sediments with increasing stand age; methane production rates decreased from 0.42 ng g-1 d-1 in 6-year-old stands to 0.23 ng g-1 d-1 in 64-year-old stands. High-throughput sequencing revealed a reduction in community diversity because of specific microorganism colonization and species loss, notably a decline in the relative abundance of Bathyarchaeia in sediments of 64-year-old stands. In addition, mangrove sediments, especially those in older stands (20- and 64-year-old), had more complex and stable co-occurrence microbial networks than mudflats. Furthermore, archaea community assembly in older stands was dominated by stochastic processes wherein dispersal limitation was prominent, and that in younger stands (6- and 12-year-old) was driven by deterministic processes. The proportion of dispersal limitation of Bathyarchaeia and traditional methanogens in sediment decreased with an increase in stand age. Quantitative polymerase chain reaction analysis confirmed a decrease in Bathyarchaeia (from 3.50 to 0.54 copies g-1) and mcrA gene (from 3.83 to 0.25 copies g-1) abundance in mangrove sediments with an increase in stand age. These findings demonstrate the critical role of Bathyarchaeia in methanogenesis; the decline in microbial interactions and abundance, and the reduced proportion of dispersal limitation of Bathyarchaeia and traditional methanogens collectively contributed to the mitigation of microbial-mediated methane production potential in older mangrove stands.

Mangrove tree aerial root extract mediated green synthesis of Ag/Fe3O4/rGO nanocomposite and its application as a catalyst for one pot synthesis of 7-phenyl-6H,7H-benzo[4,5]imidazo[2,1-b]chromeno[4,3-d][1,3]thiazin-6-one derivatives.

In this study, we report the green preparation of magnetically separable Ag/Fe3O4/rGO nanocomposites using mangrove tree aerial root extract as a stabilising agent. The morphology, size, chemical composition, magnetic property and other characteristic parameters of synthesised Ag/Fe3O4/rGO nanocomposite were determined by analytical techniques like Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The results proved that mangrove tree aerial root extract has the ability to reduce Ag+ ions, graphene oxide (GO) to Ag nanoparticle and reduced graphene oxide (rGO), respectively. The prepared Ag/Fe3O4/rGO nanocomposite was used successfully as a prompt catalyst for synthesis of 7-phenyl-6H,7H-benzo[4,5]imidazo[2,1-b]chromeno[4,3-d][1,3]thiazin-6-one derivatives by one-pot multi-component reaction of 4-hydroxycoumarin (10 mmol), 2-mercaptobenzimidazole (10 mmol) and different arylaldehyde (10 mmol) in the presence of ethanol (10 ml) as an eco-benign solvent at reflux condition. By utilising this protocol, we have constructed 7-phenyl-6H,7H-benzo[4,5]imidazo[2,1-b]chromeno[4,3-d][1,3]thiazin-6-one derivatives in good to excellent yield of 80-90%. This synthesis involves the formation of C-C, C-N and C-S bonds. The synthesised organic heterocyclic compounds were examined for the green matrix properties such as atom economy (AE), E-factor and product mass intensity (PMI). This green protocol is of big interest due to employing simple, non-toxic heterogeneous, separable, reusable Ag/Fe3O4/rGO as an eco-safe heterogeneous catalyst and environmentally benign ethanol as a green solvent without the use of any harmful mineral acid and toxic transition metal catalyst.

Deciphering how endogenous mangrove litterfall influences organic matters transformation driven by microbes in sediment with exogenous microplastics inputs.

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.

Rhizospheric bacterial communities against microplastics (MPs): Novel ecological strategies based on the niche differentiation.

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.

Optimizing mangrove afforestation: Mollusc biodiversity comparisons reveal optimal mudflat-mangrove area ratio.

In recent decades, mangrove wetlands globally have suffered from human activities and climate change, leading to issues like area reduction, degraded ecological functions and declining biodiversity. Restoration efforts, primarily through mangrove afforestation (i.e. mangrove plantation in mudflats), have been widespread, yet they often overlook the significance of unvegetated mudflats. In addition, under the condition that the total area of suitable mudflats is limited, the problem of what is the threshold of mangrove forests and unvegetated mudflats to better protect mangrove biodiversity has not been solved. Therefore, this study conducted a field survey of molluscs in mangrove wetlands in Hainan Island in China and explored the relative importance of mangroves and unvegetated mudflats through taxonomic alpha diversity and functional diversity. The results showed that (1) mollusc abundance of unvegetated mudflats was notably higher than this of mangrove forests, and the species richness, functional richness and functional vulnerability were significantly lower than those of mangrove forests; (2) the abundance and functional vulnerability of molluscs were mainly affected by sediment properties (pH, interstitial water salinity, median diameter, total nitrogen, C/N ratio), while the species richness and functional richness of molluscs were primarily influenced by vegetation structure (plant density); and (3) retaining at least 20% of the unvegetated mudflat area could well protect the biodiversity of mangrove wetlands. To our knowledge, our study is the first to propose the proportion of mangrove forests and unvegetated mudflats on the basis of benthic biodiversity, providing theoretical support and decision-making reference for mangrove protection and restoration.

Genome sequence of Sulfurimonas sp. C5, a potential chemolithoautotrophic, sulfur-oxidizing bacterium isolated from a mangrove sediment.

Sulfurimonas sp. strain C5 (MCCC 1A19556) is a strain with potential chemolithoautotrophic sulfur-oxidizing function, which is isolated from a mangrove sediment sample collected from Quanzhou Bay, Fujian Province, China. This report describes the genome sequence of strain C5, which possesses the gene sets for the sulfur-oxidizing pathway.

AmTPS6 promotes trehalose biosynthesis to enhance the Cd tolerance in mangrove Avicennia marina.

Cadmium (Cd) pollution poses a significant ecological risk to mangrove ecosystems. Trehalose has excellent potential to mitigate the adverse effects of heavy metals. Unfortunately, the mechanisms related to trehalose-mediated heavy metal tolerance in plants remain elusive. In the present study, we firstly found that Cd induced the accumulation of trehalose and the differential expression of trehalose biosynthesis genes in the roots of mangrove plant Avicennia marina. Then, we found that the application of exogenous trehalose could alleviate the negative effects of Cd on A. marina by phenotypic observation. In addition, photosynthetic parameters and cellular ultrastructure analyses demonstrated that exogenous trehalose could improve the photosynthesis and stabilize the chloroplast and nuclear structure of the leaves of A. marina. Besides, exogenous trehalose could inhibit the Cd2+ influx from the root to reduce the Cd2+ content in A. marina. Subsequently, substrate sensitivity assay combined with ion uptake analysis using yeast cells showed that several trehalose biosynthesis genes may have a regulatory function for Cd2+ transport. Finally, we further identified a positive regulatory factor, AmTPS6, which enhances the Cd tolerance in transgenic Arabidopsis thaliana. Taken together, these findings provide new understanding to the mechanism of Cd tolerance in mangrove A. marina at trehalose aspect and a theoretical basis for the conservation of mangroves in coastal wetlands.

A retrospective observational study of mangrove pit viper envenomation presented to selangor middle zone cluster hospitals in Malaysia.

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.

Occurrence, Source Apportionment, and Risk Assessment of Antibiotics in Mangrove Sediments from the Lianzhou Bay, China.

In recent years, the widespread application of antibiotics has raised global concerns, posing a severe threat to ecological health. In this study, the occurrence, source, and ecological risks of 39 antibiotics belonging to 5 classes in mangrove sediments from Lianzhou Bay, China, were assessed. The total concentrations of the antibiotics (∑39 antibiotics) ranged from 65.45 to 202.24 ng/g dry weight (dw), with an average of 142.73 ± 36.76 ng/g dw. The concentrations of these five classes of antibiotics were as follows: Sulfonamides (SAs) > Tetracyclines (TCs) > Fluoroquinolones (QUs) > Penicillin (PCs) > Macrolides (MLs). The spatial distribution of antibiotics varied as high tidal zone > middle tidal zone > low tidal zone. The total organic carbon (TOC), pH, nitrate (NO3--N), and nitrite (NO2--N) of the sediment significantly influenced the distribution of antibiotics (p < 0.05). A source analysis identified untreated sewage from aquaculture as the primary source of antibiotics in the local mangrove. A risk assessment revealed that ciprofloxacin, norfloxacin, ofloxacin of QUs, and tetracycline of TCs exhibited medium risks to algae in certain sampling sites, while other antibiotics exhibited low or no risks to all organisms. Nevertheless, the total risk of all the detected antibiotics to algae was medium in 95% of the sites. The overall ecological risk level of antibiotics in the middle tidal zone was slightly lower than in the high tidal zone and the lowest in the low tidal zone. In summary, the experimental results provided insights into the fate and transport behaviors of antibiotics in mangrove sediments from Lianzhou Bay.

Unveiling a New Antimicrobial Peptide with Efficacy against P. aeruginosa and K. pneumoniae from Mangrove-Derived Paenibacillus thiaminolyticus NNS5-6 and Genomic Analysis.

This study focused on the discovery of the antimicrobial peptide (AMP) derived from mangrove bacteria. The most promising isolate, NNS5-6, showed the closest taxonomic relation to Paenibacillus thiaminolyticus, with the highest similarity of 74.9%. The AMP produced by Paenibacillus thiaminolyticus NNS5-6 exhibited antibacterial activity against various Gram-negative pathogens, especially Pseudomonas aeruginosa and Klebsiella pneumoniae. The peptide sequence consisted of 13 amino acids and was elucidated as Val-Lys-Gly-Asp-Gly-Gly-Pro-Gly-Thr-Val-Tyr-Thr-Met. The AMP mainly exhibited random coil and antiparallel beta-sheet structures. The stability study indicated that this AMP was tolerant of various conditions, including proteolytic enzymes, pH (1.2-14), surfactants, and temperatures up to 40 °C for 12 h. The AMP demonstrated 4 µg/mL of MIC and 4-8 µg/mL of MBC against both pathogens. Time-kill kinetics showed that the AMP acted in a time- and concentration-dependent manner. A cell permeability assay and scanning electron microscopy revealed that the AMP exerted the mode of action by disrupting bacterial membranes. Additionally, nineteen biosynthetic gene clusters of secondary metabolites were identified in the genome. NNS5-6 was susceptible to various commonly used antibiotics supporting the primary safety requirement. The findings of this research could pave the way for new therapeutic approaches in combating antibiotic-resistant pathogens.

Genomic convergence in terrestrial root plants through tandem duplication in response to soil microbial pressures.

Despite increasing reports of convergent adaptation, evidence for genomic convergence across diverse species worldwide is lacking. Here, our study of 205 Archaeplastida genomes reveals evidence of genomic convergence through tandem duplication (TD) across different lineages of root plants despite their genomic diversity. TD-derived genes, notably prevalent in trees with developed root systems embedded in soil, are enriched in enzymatic catalysis and biotic stress responses, suggesting adaptations to environmental pressures. Correlation analyses suggest that many factors, particularly those related to soil microbial pressures, are significantly associated with TD dynamics. Conversely, flora transitioned to aquatic, parasitic, halophytic, or carnivorous lifestyles-reducing their interaction with soil microbes-exhibit a consistent decline in TD frequency. This trend is further corroborated in mangroves that independently adapted to hypersaline intertidal soils, characterized by diminished microbial activity. Our findings propose TD-driven genomic convergence as a widespread adaptation to soil microbial pressures among terrestrial root plants.

Functional traits of macrobenthos substantially indicated habitat change from the invasive saltmarsh to introduced mangrove.

Mangrove afforestation is usually thought to be beneficial to mitigate the degradation and loss of mangroves. In Southern China, planting mangroves with the introduced Sonneratia apetala is also supportive to remove the invasive Spartina alterniflora. However, the influence of mangrove afforestation dominated by introduced species on macrobenthos, a vital joint of energy flow and nutrient cycling in mangroves, remains unclear. We explored the linkage between the functional traits of macrobenthos and the physicochemical properties of sediments in a coastal continuum including the mudflat (MF), exotic Spartina alterniflora saltmarsh (SL), natural Avicennia marina forest (AM), and introduced S. apetala afforestation (SA) via a seasonal field survey. After removing the S. alterniflora invaded into mudflat via S. apetala afforestation, the sediment C/N ratio decreased compared to that of natural forest, while the concentrations of microphytobenthic chlorophyll-a increased. The macrobenthic inhabiting mode shifted from epifaunal to infaunal as well. The biomass and density of microbenthic community decreased along MF, SL, AM, and SA. SL had greater C/N ratio and smaller functional richness (FR) than MF. AM was characterized by similar functional diversities, and pH value and salinity of sediment to those of MF, and greater microphytobenthic chlorophyll-a was found in AM. Compared to AM, the introduced S. apetala substantially engineered the habitat due to its flourishing above-ground pneumatophore system which caused faster deposition process, subsequently changed the resource utilization strategies of macrobenthos considerably. Overall, the use of Sonneratia afforestation on Spartina removal could not replace the contribution of natural Avicennia forest with respect to the functional traits of macrobenthos. Careful consideration on ecosystem functionalities would be indispensable for conducting saltmarsh eradication and mangrove afforestation in the future.

New Bioactive Polyketides from the Mangrove-Derived Fungus Penicillium sp. SCSIO 41411.

Three new polyketides, including three ester derivatives (1, 3, and 5) and a new natural product, which was a benzoquinone derivative, embelin A (4), together with nine known ones (2 and 6-13), were isolated from the mangrove-derived fungus Penicillium sp. SCSIO 41411. Their structures were determined by detailed NMR and MS spectroscopic analyses. The X-ray single-crystal diffraction analysis of 4 was described for the first time. Compound 9 displayed obvious inhibition against PDE4 with an inhibitory ratio of 40.78% at 10 µM. Compound 12 showed DPPH radical scavenging activity, with an EC50 of 16.21 µg/mL, compared to the positive control (ascorbic acid, EC50, 11.22 µg/mL). Furthermore, compound 4 exhibited cytotoxicity against PC-3 and LNCaP with IC50 values of 18.69 and 31.62 µM, respectively.

Two C23-Steroids and a New Isocoumarin Metabolite from Mangrove Sediment-Derived Fungus Penicillium sp. SCSIO 41429.

Two new C23-steroids derivatives, cyclocitrinoic acid A (1) and cyclocitrinoic acid B (2), and a new isocoumarin metabolite, (3R,4S)-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 IC50 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 IC50 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.

New Sesquiterpenoids from the Mangrove-Derived Fungus Talaromyces sp. as Modulators of Nuclear Receptors.

Four new sesquiterpenoids, talaroterpenes A-D (1-4), were isolated from the mangrove-derived fungus Talaromyces sp. SCSIO 41412. The structures of compounds 1-4 were elucidated through comprehensive NMR and MS spectroscopic analyses. The absolute configurations of 1-4 were assigned based on single-crystal X-ray diffraction and calculated electronic circular dichroism analysis. Talaroterpenes A-D (1-4) were evaluated with their regulatory activities on nuclear receptors in HepG2 cells. Under the concentrations of 200 µM, 1, 3 and 4 exhibited varying degrees of activation on ABCA1 and PPARα, while 4 showed the strongest activities. Furthermore, 4 induced significant alterations in the expression of downstream target genes CLOCK and BMAL1 of RORα, and the in silico molecular docking analysis supported the direct binding interactions of 4 with RORα protein. This study revealed that talaroterpene D (4) was a new potential non-toxic modulator of nuclear receptors.

The Cytochalasins and Polyketides from a Mangrove Endophytic Fungus Xylaria arbuscula QYF.

Twelve compounds, including four undescribed cytochalasins, xylariachalasins A-D (1-4), four undescribed polyketides (5-8), and four known cytochalasins (9-12), were isolated from the mangrove endophytic fungus Xylaria arbuscula QYF. Their structures and absolute configurations were established by extensive spectroscopic analyses (1D and 2D NMR, HRESIMS), electronic circular dichroism (ECD) calculations, 13C NMR calculation and DP4+ analysis, single-crystal X-ray diffraction, and the modified Mosher ester method. Compounds 1 and 2 are rare cytochalasin hydroperoxides. In bioactivity assays, Compound 2 exhibited moderate antimicrobial activities against Staphylococcus aureus and Candida albicans with MIC values of 12.5 µM for both Compound 10 exhibited significant cytotoxic activity against MDA-MB-435 with an IC50 value of 3.61 ± 1.60 µM.

Methods Using Marine Aquatic Photoautotrophs along the Qatari Coastline to Remediate Oil and Gas Industrial Water.

Qatar and other Gulf States have a diverse range of marine vegetation that is adapted to the stressful environmental conditions of seawater. The industrial wastewater produced by oil and gas activities adds further detrimental conditions for marine aquatic photosynthetic organisms on the Qatari coastlines. Thus, these organisms experience severe stress from both seawater and industrial wastewater. This review discusses the biodiversity in seawater around Qatar, as well as remediation methods and metabolic pathways to reduce the negative impacts of heavy metals and petroleum hydrocarbons produced during these activities. The role of microorganisms that are adjacent to or associated with these aquatic marine organisms is discussed. Exudates that are released by plant roots enhance the role of microorganisms to degrade organic pollutants and immobilize heavy metals. Seaweeds may have other roles such as biosorption and nutrient uptake of extra essential elements to avoid or reduce eutrophication in marine environments. Special attention is paid to mangrove forests and their roles in remediating shores polluted by industrial wastewater. Seagrasses (Halodule uninervis, Halophila ovalis, and Thalassia hemprichii) can be used as promising candidates for phytoremediation or bioindicators for pollution status. Some genera among seaweeds that have proven efficient in accumulating the most common heavy metals found in gas activities and biodegradation of petroleum hydrocarbons are discussed.

Characterization and mechanism of phthalic acid esters bioaccumulation in dominant mangrove fish at different habitats in the mangrove ecosystem of Dongzhai Harbor, China.

With the wide application of phthalic acid esters (PAEs) in the manufacturing of plastic products, a large number of PAEs were discharged into marine ecosystem and accumulated in fish, which has posed a serious threat to marine ecological environment and fishery resources. However, the bioaccumulation of PAEs in fish in mangrove ecosystem, the most productive marine ecosystem, has not been well characterized. In this study, dominant fish and their potential food sources (including particulate organic matter (POM), sedimentary organic matter (SOM), Metapenaeus ensis (Shrimp) and Oreochromis (Ore) were collected from Dongzhai Harbor, a typical mangrove ecosystem. The concentrations of nine PAEs in fish and their potential food sources were determined. Then stable nitrogen and carbon isotope analysis, combined with a new Bayesian mixing model (MixSIMMR) was used to quantify the diet compositions of fish and elucidate the effect of dietary habit on PAEs bioaccumulation in fish. The results indicated that the median concentration of ∑9PAEs in fish was 1119 µg/kg ww, positioning it at a moderate to low level in comparison to other regions. di-n-butyl phthalate (DBP) and diisononyl ortho-phthalate (DINP) were the dominant PAEs in fish. The PAEs concentration in demersal fish was significantly higher than that of pelagic fish, which may be attributed to the substantial contributions of shrimp (28.5 %) and POM (25.3 %) to the diet of demersal fish. This study provided new insights on the bioaccumulation of PAEs in dominant mangrove fish and confirmed that habitat preferences and food sources could significantly influence the bioaccumulation of PAEs in fish.

Isochromophilones H-K, the new bioactive azaphilone derivatives isolated from fungal strain Diaporthe perseae associated with Pongamia pinnata plant.

The phytochemical study of the Diaporthe species has revealed significant classes of mycotoxins and phomopsins. Dihydroanthracenone derivatives, chromanones and isochromophilones have also been isolated from Diaporthe sp. These findings led us to explore the Diaporthe perseae for phytochemical analysis that resulted in the isolation of four new compounds designated as isochromophilones H-K (1-4), alongside three previously identified metabolites. Using extensive spectroscopic investigations such as NMR, and Mass spectroscopy, their structures were elucidated. Furthermore, the antimicrobial and anti-diabetic potentials of all isolated compounds were assessed. Compounds 1-3 demonstrated significant antibacterial activity, while compounds 4-7 exhibited comparatively lower effectiveness than the reference antibiotics. Compounds 2-3 showed potent diabetic inhibition, displaying IC50 values of 16.3 ± 0.3 and 25.4 ± 0.3, respectively. Compounds 1, 5, and 6 displayed mild anti-diabetic effects, with IC50 values of 56.5 ± 0.8, 37.6 ± 0.4, and 48.2 ± 0.6. However, compounds 4 and 7 were found least active.