Institutional Repository of Yantai Institute of Coastal Zone Research, CAS
Not a member yet
13079 research outputs found
Sort by
Shining light on carbon dots: Toward enhanced antibacterial activity for biofilm disruption
No full textIn spite of tremendous efforts dedicated to addressing bacterial infections and biofilm formation, the post-antibiotic ear continues to witness a gap between the established materials and an easily accessible yet biocompatible antibacterial reagent. Here we show carbon dots (CDs) synthesized via a single hydrothermal process can afford promising antibacterial activity that can be further enhanced by exposure to light. By using citric acid and polyethyleneimine as the precursors, the photoluminescence CDs can be produced within a one-pot, one-step hydrothermal reaction in only 2 h. The CDs demonstrate robust antibacterial properties against both Gram-positive and Gram-negative bacteria and, notably, a considerable enhancement of antibacterial effect can be observed upon photo-irradiation. Mechanistic insights reveal that the CDs generate singlet oxygen (1O2) when exposed to light, leading to an augmented reactive oxygen species level. The approach for disruption of biofilms and inhibition of biofilm formation by using the CDs has also been established. Our findings present a potential solution to combat antibacterial resistance and offer a path to reduce dependence on traditional antibiotics.
Shining carbon dots (CDs) produced by a single-step hydrothermal method can afford enhanced antibacterial activity against both Gram-positive and Gram-negative bacteria. Mechanistic insights reveal that the CDs generate singlet oxygen (1O2) under light irradiation, contributing to an augmented ROS level, facilitating disruption of biofilms and inhibition of biofilm formation. imag
Vertical transfer of microplastics in nearshore water by cultured filter-feeding oysters
No full textMicroplastics (MPs) are widely distributed in the sea, but the vertical transfer of MPs by marine organisms in coastal area is still poorly understood. In this study, we used laser direct infrared (LDIR) spectroscopy to determine the number and characteristics of MPs deposited by cultured oyster Crassostrea gigas and further compared the differences between MPs of natural deposit and biodeposit in field environments. The amounts of MPs found in the biodeposit of cultured oysters were 3.54 times greater than that in the natural deposition. The polymer types of biodeposit MPs also differed from those of natural deposition. It was estimated that a single oyster can deposit 15.88 MPs per day, which is a figure much higher than the initial results, and hotspots of MPs deposition may be formed within the oyster aquaculture area. We used generalized linear mixed model (GLMM) to further infer the sources of MPs in sediments and found that distance to shore, cultured zone and urban center were important predictors of MPs abundance in sediments of aquaculture area. The above results suggest tha
Evaluation of monoamine oxidase B fluctuation in liver fibrosis cell and mice models via a specificity fluorescent probe
No full textLiver fibrosis can result in cirrhosis and cancer, leading to damage to liver function and even endangering life. Early diagnosis of fibrosis is essential for optimizing the therapeutic schedule and improving the cure rates. Recent researches have shown that monoamine oxidase B (MAO-B) could be used as the marker for the early diacrisis of liver fibrosis. However, there still lacked strategies for accurate in situ monitoring of MAO-B. In this work, we developed a fluorescence probe YXHcy-NH2 for detecting MAO-B activity in living cells and in vivo. MAO-B activates the probe within 100 minutes and emits bright fluorescence at the fluorescence emission peak. The results displayed that the fluorescence intensity of fibrotic LX-2 cells was ten times that of normal cells, and the fluorescence brightness of liver tissues in liver fibrotic mice was five times higher than that of normal mice, so our probe could successfully distinguish between fibrotic cells and normal cells, as well as liver fibrotic mice and normal mice. Our study provides an easy, rapid, and high sensitive method for in situ in vivo imaging of MAO-B. It may become an effective mean for early diagnosis of liver fibrosis
N 2 O emission in temperate seagrass meadows: Fluxes, pathway and molecular mechanism
No full textSeagrass meadows act as filters for nitrogen in coastal areas, but whether they are a source or sink for N 2 O has been still controversy. Additionally, the production pathways of N 2 O as well as the microbial driving mechanism in seagrass meadows are seldom reported. In this study, the air-sea fluxes, sediment release potential, and production pathway of N 2 O in a temperate Zostera marina and Z. japonica mixed meadow were investigated by using gas chromatography and 15 N isotopic tracing methods. The qPCR and metagenome sequencing were used to compare the difference in functional gene abundance and expression between seagrass vegetated and nongrass sediments. The results showed that the N 2 O air-sea fluxes in the meadow ranged from -1.97 to -1.77 nmol m - 2 h - 1 , which was slightly lower in the seagrass region than in the adjacent bare region. Seagrass sediment N 2 O release potential dramatically increased after warming and nitrogen enrichment treatments. Heterotrophic nitrification was firstly investigated in seagrass meadows, and the process (26.80% -62.41%) and denitrification (37.55% -72.83%) contributed significantly to N 2 O production in the meadow, affected deeply by sediment organic content, while the contribution of autotrophic nitrification can be neglected. Compared with the bare sediments, the ammonia monooxygenase genes amoA , amoB and amoC , and nitrite oxidoreductase genes nxrA and nxrB , as well as nitrite reductase gene nirS and nitric oxide reductase gene norB were down-regulated, while the nitrous oxide reductase gene nosZ was up-regulated in the seagrass sediments, explaining less N 2 O emission in seagrass regions from the perspective of molecular. The nosZII -bearing bacteria like Bacteroidia , Polyangia , Anaerolineae , and Verrucomicrobiae could play important roles in N 2 O reduction in the seagrass meadow. The result is of great significance for highlighting the ability of seagrass meadows to mitigate climate changes
An exonuclease I-assisted quencher-free 2-aminopurine aptasensor based on a multipath paper-based device for ultrasensitive detection of kanamycin
No full textA quencher-free multipath microfluidic paper-based analytical device (mu PAD) was constructed for ultrasensitive detection of kanamycin based on exonuclease I (Exo I)-assisted signal enhancement of 2-aminopurine (2-AP). Here, Exo I, a single-stranded DNA-specific nuclease, was introduced to fully liberate 2-AP mononucleotides to greatly enhance biosensing sensitivity. 2-AP, a fluorescent adenine analogue embedded in single-stranded DNA (ssDNA), was employed as the detection signal source. The fluorescence of 2-AP is strong in the mononucleotide state, while it can have low fluorescence and even no fluorescence in ssDNA and dsDNA, respectively. The 2-AP fluorescence probe included 2-AP DNA and kanamycin aptamer. When kanamycin was present, binding occurred between kanamycin and the aptamer, leading to ssDNA, which was further digested by Exo I. In this case, free 2AP mononucleotides were liberated, indicating strong fluorescence. In addition, the captured kanamycin was released for binding with the new aptamer, which resulted in the formation of a binding-hydrolysis-release cycle with the aid of Exo I. Under optimal conditions, this mu PAD exhibited sensitive and multipath detection of kanamycin at concentrations as low as 1.26 x 10-14 M with a wide range of 10- 13-10- 7 M. Furthermore, satisfactory results were achieved for analysing spiked kanamycin in milk and honey samples. This strategy is a very promising tool for monitoring antibiotics and evaluating the safety of animal-derived foods
The influences of Yellow River input and nutrient dynamics on colloidal Fe migration in the Bohai Sea, China
No full textThe coupling relationship between the <1 kDa, 1-3 kDa, 3-10 kDa, 10-100 kDa, and 100 kDa-0.45 mu m Fe fractions and the environmental factors in the Bohai Sea (BS) was investigated. The 1-100 kDa Fe in the surface water exhibited a non-conservative phenomenon during the river-sea mixing process, which was related to the removal of colloidal Fe via flocculation during this process. For the bottom water, the ligands released by the sediments may form additions to the <100 kDa Fe. The COC and DOC were mainly closely related to the behavior of the Fe in the bottom water. The <1 and 3-10 kDa Fe was mainly significantly positively correlated with the DOC, while the <100 kDa-0.45 mu m Fe was significantly negatively correlated with the DOC. <100 kDa LMW colloidal Fe exhibited more synergistic behavior with easily absorbed ammonium salts
Fuzzy graph convolutional network for hyperspectral image classification
No full text-Graph convolutional network (GCN) has attracted much attention in the field of hyperspectral image classification for its excellent feature representation and convolution on arbitrarily structured non-Euclidean data. However, most state-of-the-art methods build a graph utilize the distance measure, which makes it challenging to fully characterize the complex relationship of hyperspectral remote sensing data. Moreover, the hyperspectral image usually has uncertainty introduced by the problems of the spectral variability and noise interference. This article uses fuzzy theory to optimize the GCN and thus solve the uncertainty problem in hyperspectral images, and presents a novel fuzzy graph convolutional network (F-GCN) for hyperspectral image classification. By calculating the fuzzy similarity of samples, a robust graph is first built rather than using the traditional Euclidean distance method, which allows a better representation of the complex relationship between hyperspectral remote sensing data. Furthermore, the proposed network introduces fuzzy layers into the model to cope with the ambiguity of the hyperspectral image. Finally, the classification results for three real-world hyperspectral data sets to show its feasibility and effectiveness in hyperspectral image classification
Fuzzy graph convolutional network for hyperspectral image classification
No full text-Graph convolutional network (GCN) has attracted much attention in the field of hyperspectral image classification for its excellent feature representation and convolution on arbitrarily structured non-Euclidean data. However, most state-of-the-art methods build a graph utilize the distance measure, which makes it challenging to fully characterize the complex relationship of hyperspectral remote sensing data. Moreover, the hyperspectral image usually has uncertainty introduced by the problems of the spectral variability and noise interference. This article uses fuzzy theory to optimize the GCN and thus solve the uncertainty problem in hyperspectral images, and presents a novel fuzzy graph convolutional network (F-GCN) for hyperspectral image classification. By calculating the fuzzy similarity of samples, a robust graph is first built rather than using the traditional Euclidean distance method, which allows a better representation of the complex relationship between hyperspectral remote sensing data. Furthermore, the proposed network introduces fuzzy layers into the model to cope with the ambiguity of the hyperspectral image. Finally, the classification results for three real-world hyperspectral data sets to show its feasibility and effectiveness in hyperspectral image classification
Rapidly reducing cadmium from contaminated farmland soil by novel magnetic recyclable Fe3O4/mercapto-functionalized attapulgite beads
No full textReducing cadmium (Cd) content from contaminated farmland soils remains a major challenge due to the difficulty in separating commonly used adsorbents from soils. This study synthesized novel millimeter-sized magnetic Fe3O4/mercapto-functionalized attapulgite beads (MFBs) through a facile one-step gelation process incorporating alginate. The MFBs inherit the environmental stability of alginate and enhance its mechanical strength by hybridizing Fe3O4 and clay mineral components. MFBs can be easily separated from flooded soils by magnets. When applied to 12 Cd-polluted paddy soils and 14 Cd-polluted upland soils, MFBs achieved Cd(II) removal rates ranging from 16.9% to 62.2% and 9.8%-54.6%, respectively, within a 12-h period. The MFBs predominantly targeted the exchangeable and acid soluble, and reducible fractions of Cd, with significantly enhanced removal efficiencies in paddy soils compared to upland soils. Notably, MFBs exhibited superior adsorption performance in soils with lower pH and organic matter (OM) content, where the bioavailability and mobility of Cd are heightened. The reduction of Cd content by MFBs is a sustainable and safe method, as it permanently removes the bioavailable Cd from soil, rather than temporarily reducing its bioavailability. The functional groups such as -SH, -OH, present in attapulgite and alginate of MFBs, played a crucial role in Cd(II) adsorption. Additionally, attapulgite and zeolite provided a porous matrix structure that further enhanced Cd(II) adsorption. The results of X-ray photoelectron spectroscopy suggested that both chemical precipitation and surface complexation contributed to Cd(II) removal. The MFBs maintained 87.6% Cd removal efficiency after 5 regeneration cycles. The surface of the MFBs exposed new adsorption sites and increased the specific surface area during multiple cycles with Cd-contaminated soil. This suggests that MFBs treatment with magnetic retrieval is a potentially effective pathway for the rapid removal of Cd from contaminated farmland soils
Low molecular weight chitosan based GSH-responsive self-assembled cationic micelle with enhanced anti-tumor effect by combining oxidative damage and chemotherapy
No full textA novel cationic lipoic acid grafted low molecular weight chitosan (LCNE-LA) conjugate was constructed and further self-assembled into GSH-responsive cationic nanocarrier to achieve better antitumor effect by combining encapsulated chemotherapy and oxidative damage induced by ROS. The resultant LCNE-LA cationic micelle exhibited favorable physicochemical properties (low CMC, small size, positively zeta potential and good stability), excellent biosafety and desired redox sensitivity. Next, doxorubicin (Dox) was embedded into hydrophobic core to form stable Dox/LCNE-LA micelle that had superior loading capacity. The GSH-induced release behavior, cellular uptake ability, ROS generation and GSH consumption capacity and in vitro antitumor activity of Dox/LCNE-LA micelle were systematically evaluated. Consequently, Dox/LCNE-LA cationic micelle with positively charged could efficiently enter into cancer cell and redox-sensitive release Dox via disulfide-thiol exchange reaction, which usually expend abundant GSH and disrupt redox homeostasis. Studies further confirmed that Dox/LCNE-LA micelle could increase ROS and reduced GSH content which might cause oxidative damage to tumor cell. Antitumor activity indicated that Dox/LCNE-LA micelle achieved an excellent cancerkilling effect, which might be attributed to combination treatment of Dox and ROS induce oxidative damage. Overall, this research was expected to provide a platform for antitumor treatment by triggering Dox release and promoting ROS generation