查看更多>>摘要：Per-and polyfluoroalkyl substances(PFASs)are emerging persistent organic pollutants(POPs).In this study,47 surface sediment samples were collected from the Yellow River Delta wetland(YRDW)to investigate the occurrence,spatial distribution,potential sources,and ecological risks of PFASs.Twenty-three out of 26 targeted PFASs were detected in surface sediment samples from the YRDW,with total ∑23PFASs concentrations ranging from 0.23 to 16.30 ngg1dw and a median value of 2.27ngg 1 dw.Perfluorooctanoic acid(PFOA),perfluorobutanoic acid(PFBA)and perfluorooctanesulfonic acid(PFOS)were the main contami-nants.The detection frequency and concentration of perfluoroalkyl carboxylic acids(PFCAs)were higher than those of perfluoroal-kanesulfonic acids(PFSAs),while those of long-chain PFASs were higher than those of short-chain PFASs.The emerging PFASs substitutes were dominated by 6:2 chlorinated polyfluoroalkyl ether sulfonic acid(6:2 Cl-PFESA).The distribution of PFASs is sig-nificantly influenced by the total organic carbon content in the sediments.The concentration of PFASs seems to be related to human activities,with high concentration levels of PFASs near locations such as beaches and villages.By using a positive matrix factoriza-tion model,the potential sources of PFASs in the region were identified as metal plating mist inhibitor and fluoropolymer manufac-turing sources,metal plating industry and firefighting foam and textile treatment sources,and food packaging material sources.The risk assessment indicated that PFASs in YRDW sediments do not pose a significant ecological risk to benthic organisms in the region overall,but PFOA and PFOS exert a low to moderate risk at individual stations.
查看更多>>摘要：Methyl halides are crucial trace greenhouse gases in the atmosphere,playing a significant role in global climate change and the atmospheric environment.This study investigated the photochemical production of methyl halides in an artificial seawater system using guaiacol as a precursor through laboratory simulation experiments.The influences of various environmental factors,including illumination time,radiation wavebands,illumination intensity,concentrations of guaiacol and halide ions(X-),Fe3+,salin-ity,dissolved oxygen(DO),and pH value on the photochemical production of methyl halides were examined.We demonstrated that increased illumination intensity and duration promote the photochemical production of methyl halides,with a notable enhancement under UV-B radiation.Guaiacol and halide ions were identified as key precursors,and their high concentrations facilitated the forma-tion of methyl halides.Additionally,different types of halide ions exhibited a competitive relationship in producing methyl halides.The study found that an increase in pH inhibited the photochemical formation of CH3I due to the reaction between OH-and·CH3.Dissolved oxygen was found to inhibit the photochemical formation of CH3I while promoting the formation of CH3C1.Conversely,an appropriate concentration of Fe3+enhanced the photochemical production of methyl halides.Field observations indicated a high photochemical production of methyl halides in the natural waters near Qingdao's coastal area,likely due to the high concentration of dissolved organic matter(DOM),which supports photochemical reactions.Furthermore,the photochemical production of methyl halides in natural seawater was significantly higher than in dark conditions,underscoring the importance of illumination in promoting these photochemical processes in seawater.
查看更多>>摘要：Long-chain alkenones(LCAs)have been widely used as important biomarkers in palaeoceanographic studies.However,the commonly used LCAs proxies are mainly based on C37 alkenones,and it is still lack of the studies about the distribution and in-dications of LCAs with different chain lengths other than C37 alkenones.Here,the composition and distribution of LCAs were ana-lyzed in surface sediments from the southern Yellow Sea(SYS)and a sedimentary core(A02-C)from the central Yellow Sea(YS)mud area.The results showed that C37,C38 and C39 alkenones were the major LCAs in surface sediments of the SYS,and the relative contents of C38:2Et,C37:2Me,C37:3Me,C38:2Me,C38:3Et,C38:3Me,C39:2Et and C39:3Et were 18.3％-59.8％,22.6％-41.2％,7.4％-23.0％,6.6％-15.4％,3.8％-13.3％,3.6％-8.7％,2.8％-6.0％and 0.7％-3.0％,respectively.Then the relationships of UK38Me-UK38Et and UK'37-UK38Et,indicate that LCAs are mainly derived from Emiliania huxleyi(E.huxleyi).High ratios of total C37 alkenones to total C38 alkenones(K37/K38)(1-1.2)were found in the central SYS,corresponding to the relatively high abundance of E.huxleyi;while low ratios of K37/K38(0.7-0.9)were observed at nearshore area of the SYS where Gephyrocapsa oceanica(G.oceanica)has rela-tively high abundance.The spatial distribution of K37/K38 ratio is also consistent with that of coccolithophores nannofossil in the sediments.In addition,K37/K38 ratio in core A02-C varied from 0.7 to 1.1 with a gradual decreasing trend during the past 5.5 kyr.This suggests that the relative abundance of E.huxleyi decreased gradually,caused by the changes in the Yellow Sea Warm Current(YSWC)and the East Asian Winter Monsoon(EAWM)during this period.
查看更多>>摘要：Marine natural products(MNPs)are valuable resources for drug development.To date,17 drugs from marine sources are in clinical use,and 33 pharmaceutical compounds are in clinical trials.Presently the success of drug development from the marine resources is higher than the industry average.It is a feasible strategy to conduct the discovery of drug-lead compounds based on ma-rine chemical ecology by fully exploiting the pharmacological potential of marine chemical defense matters.In the search for bioac-tive MNPs,our group has constructed a biological resources library including more than 1500 strains of fungi.Focusing on the strate-gy of Blue Drug Library,we have discovered a series of novel MNPs with abundant biological functions.Highly efficient and scal-able total synthesis of(+)-aniduquinolone A(44)and pesimquinolone I(48)have been completed,which will facilitate access to suf-ficient quantities of candidates for in vivo pharmacological and toxicological studies.As a nucleoprotein(NP)inhibitor,QLA(75)pos-sesses significant anti-influenza A virus(IAV)activities both in vitro and in vivo.CHNQD-00803(76)is a potent and selective AMP-activated kinase(AMPK)activator that can effectively inhibit metabolic disorders and metabolic dysfunction-associated steatohepa-titis(MASH)progression.Moreover,we identified two new candidate molecules with potent anti-hepatocellular carcinoma effects.Particularly,as a natural guanine-nucleotide exchange factors for ADP-ribosylation factor GTPases(Arf-GEFs)inhibitor prodrug,CHNQD-01255(78)is qualified to be developed as a targeted candidate anticancer drug,which may be promising to apply for can-cer immunotherapy.Hence,it is evident that MNPs play an important role in drug development.
查看更多>>摘要：Chitin is the second most abundant renewable polysaccharide on Earth.The degradation of chitin into soluble and bioac-tive N-acetyl chitooligosaccharides(NCOSs)and N-acetyl-D-glucosamine(GlcNAc)has emerged as a pivotal step in the efficient and sustainable utilization of chitin resources.However,because of its dense structure,high crystallinity,and poor solubility,chitin typi-cally needs pretreatment via chemical,physical,and other methods before enzymatic conversion to enhance the accessibility between substrates and enzyme molecules.Consequently,there has been considerable interest in exploring the direct biological degradation of crystalline chitin as a cost-effective and environment-friendly technology.This review endeavors to present several biological methods for the direct degradation of chitin.We primarily focused on the importance of chitinase containing chitin-binding domain(CBD).Additionally,various modification strategies for increasing the degradation efficiency of crystalline chitin were introduced.Subsequently,the review systematically elucidated critical components of multi-enzyme catalytic systems,highlighting their potential for chitin de-gradation.Furthermore,the application of microorganisms in the degradation of crystalline chitin was also discussed.The insights in this review contribute to the explorations and investigations of enzymatic and microbial approaches for the direct degradation of crystal-line chitin,thereby fostering advancements in biomass conversion.
查看更多>>摘要：Sulfated polysaccharides extracted from seaweeds,including Carrageenan,Fucoidan and Ulvan,are crucial bioactive com-pounds known for their diverse beneficial properties,such as anti-inflammatory,antitumor,immunomodulatory,antiviral,and antico-agulant effects.These polysaccharides form hydrogels hold immense promise in biomedicine,particularly in tissue engineering,drug delivery systems and wound healing.This review comprehensively explores the sources and structural characteristics of the three im-portant sulfated polysaccharides extracted from different algae species.It elucidates the gelation mechanisms of these polysaccharides into hydrogels.Furthermore,the biomedical applications of these three sulfated polysaccharide hydrogels in wound healing,drug deli-very,and tissue engineering are discussed,highlighting their potential in the biomedicine.
查看更多>>摘要：Bivalve aquaculture plays a crucial role in the aquaculture industry due to the economic value of many bivalve species.Understanding the underlying genetic basis of bivalve growth regulation is essential for enhancing germplasm innovation and ensuring sustainable development of the industry.Though numerous candidate genes have been identified,their functional validation remains challenging.Fortunately,the dwarf surf clam(Mulinia lateralis)serves as a promising model organism for investigating genetic me-chanisms underlying growth regulation in bivalves.The GWAS study in the Yesso scallop(Patinopecten yessoensis)has pinpointed the E2F3 gene as a key regulator of growth-related traits.However,the specific role of E2F3 in bivalve growth remains unclear.This study aimed to further confirm the regulatory function of the E2F3 gene in the dwarf surf clam through RNA interference experiments.Our results revealed several genes are associated with individual growth and development,including CTS7,HSP70B2,and PGLYRP3,as well as genes involved in lipid metabolism such as FABP2 and FASN.Functional enrichment analysis indicated that E2F3 primarily modulates critical processes like amino acid and lipid metabolism.These findings suggest that E2F3 likely regulates growth in the dwarf surf clam by influencing amino acid and lipid metabolism.Overall,this study advances our understanding on the function of E2F3 gene in growth regulation in bivalves,providing valuable insights for future research in this field.
查看更多>>摘要：Ocean acidification(OA),caused by the rising concentration of atmospheric CO2,leads to changes in the marine car-bonate system.This,in turn,affects the physiological processes of phytoplankton.In response to increased pCO2 levels,marine mi-croalgae modulate their physiological responses to meet their energy and metabolic requirements.Nitrogen metabolism is a critical metabolic pathway,directly affecting the growth and reproductive capacity of marine microorganisms.Understanding the molecular mechanisms that regulate nitrogen metabolism in microalgae under OA conditions is therefore crucial.This study aimed to investi-gate how OA affects the expression profiles of key genes in the nitrogen metabolic pathway of the marine diatom Skeletonema co-statum.Our findings indicate that OA upregulates key genes involved in the nitrogen metabolic pathway,specifically those related to nitrate assimilation and glutamate metabolism.Moreover,pCO2 has been identified as the predominant factor affecting the expres-sion of these genes,with a more significant impact than pH variations in S.costatum.This research not only advances our under-standing of the adaptive mechanisms of S.costatum in response to OA but also provides essential data for predicting the ecological consequences of OA on marine diatoms.
查看更多>>摘要：Jellyfish blooms are increasingly prevalent coastal phenomena,with Aurelia coerulea being a significant contributor.The complex life history of jellyfish,featuring a sessile polyp stage,is a key factor in bloom formation,yet it is challenging to study in the field.This study aimed to describe the asexual reproduction of A.coerulea polyps in Jiaozhou Bay,China,and to assess their ability to form sedentary colonies and their relationship with environmental factors.Using settling plates,we observed polyps in situ and documented three asexual reproduction modes:budding,strobilation,and podocyst formation.Environmental parameters in-cluding temperature,salinity,dissolved oxygen(DO),chlorophyll a(Chi a),and the biomass of phytoplankton and zooplankton were monitored.Budding was the predominant reproductive method,featuring stolon budding in autumn and direct budding during the winter and spring seasons.Strobilation took place in the colder months,releasing ephyrae between April and May.Polyp abundance was positively correlated with seawater temperature and negatively correlated with DO concentration.Polyps at 1.0 m depth showed higher survivorship and proliferation over 8 months,whereas those at 2.0 m depth experienced a steady decline and died within 4 months.The study enhances our understanding of the life cycle and asexual reproduction strategies of A.coerulea polyps in the field,with implications for predicting and managing jellyfish blooms.The findings underscore the importance of temperature and DO in polyp survival and suggest that initial polyp population proliferation is crucial for long-term survival.
查看更多>>摘要：Flow-slip damage commonly destabilizes coastal slopes.Finding a slope stabilization method for calcareous sands in the South China Sea is crucial.Microbially induced calcite precipitation is a promising,eco-friendly method for soil stabilization.This study investigates the effect of microbial treatments,initial relative density,initial cell pressure,and initial stress ratio on the flow-slip stability of calcareous sand specimens by using constant shear drained tests.These tests lay the foundation to study the mechanical instability of sand slopes.Results show that the microbial-treated specimens maintain stable stresses longer,take longer to reach the instability,and withstand larger volumetric strains.Microbial treatment effectively enhances sand stability under constant shear drainage,with im-provements amplified by higher initial relative density and initial cell pressure.In addition,a smaller initial stress ratio reduces shear effects on the specimen and increases resistance to flow slides.Microanalysis reveals that the flow-slip stability of calcareous sand slopes is enhanced by contact cementation,particle coating,void filling,and mutual embedment of calcium carbonate crystals.
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