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Spatial-temporal distribution and eutrophication evaluation of nutrients and trace metals in summer surface seawater of Yantai Sishili Bay, China
No full textDue to coastal development expansion, an increasing influx of pollutants enters the sea through riverine input and land runoff, threatening coastal ecosystems and posing a risk of eutrophication. In this study, trace metals (Fe, Mn, Cu, and Zn), and nutrients (constituents of N, P, and Si) were assessed in the summer surface seawater of Yantai Sishili Bay (YSB), Northern China focusing on the determination of concentration, spatial-temporal distribution and sources identification, while exploring their correlations. It also aimed to clarify the eutrophication status and evaluate the linear relationships between eutrophication, trace metals, and nutrients in YSB. Over three years (2021-2023), the total dissolved concentrations of Fe, Mn, Cu, and Zn ranged from 4.79-26.71, 0.19-6.41, 0.26-1.53, and 0.74-13.12 mu g/L, respectively. Concurrently, nutrient concentrations including NO2 -, NO3 -, NH4 +, PO4 3-, and DSi exhibited a range of 0.37-11.66, 2.04-178.30, 1.69-70.01, 0.02-16.68, and 0.02-0.71 mu g/L respectively. These concentrations revealed a gradual decrease from nearshore to offshore and the temporal variation also showed significant patterns from year to year, indicating distinct regional variations. The primary contributors to the trace metals and nutrients in the study region were recognized as external contributions stemming from natural, anthropogenic, and atmospheric deposition through correlation and principal component analysis. More specifically, riverine input and coastal farming contributed large amounts of nutrients to coastal waters, threatening a potential risk of eutrophication. The eutrophication evaluation expressed below the mild eutrophication level and was far lower than the other global and Chinese bays. The linear correlation between eutrophication and trace metals revealed a weak positive correlation but a significant correlation with nutrients. Despite the absence of significant eutrophication in the bay, potential risks were identified due to identifiable sources of nutrient and trace metal inputs. The findings provided insights to guide efforts in preventing and mitigating coastal eutrophication, as well as nutrient and trace metal pollution, in coastal cities
Exploring the innate immune system of Urechis unicinctus: Insights from full-length transcriptome analysis
No full textThe Echiura worm Urechis unicinctus refers to a common benthic invertebrate found in the intertidal zone of Huanghai as well as Bohai Bay. U. unicinctus is known to contain various physiologically active substances, making it highly valuable in terms of its edibility, medicinal properties, and economic potential. Nonetheless, the limited study on the immune system of U. unicinctus poses difficulties for its aquaculture and artificial reproduction. Marine invertebrates, including shellfish and U. unicinctus, , are thought to primarily depend on their innate immune system for disease protection, owing to the several innate immune molecules they possess. Herein, we employed PacBio single-molecule real-time (SMRT) sequencing technology to perform the full-length transcriptome analysis of U. unicinctus individuals under five different conditions (room temperature (RT), low temperature (LT), high temperature (HT), without water (DRY), ultraviolet irradiation (UV)). Concequently, we identified 59,371 unigenes that had a 2,779 bp average length, 2,613 long non-coding RNAs (lncRNAs), 59,190 coding sequences (CDSs), 35,166 simple sequence repeats (SSRs), and 1,733 transcription factors (TFs), successfully annotating 90.58% (53,778) of the unigenes. Subsequently, key factors associated with immune-related processes, such as non-self-recognition, cellular immune defenses, and humoral immune defenses, were searched. Our study also identified pattern recognition receptors (PRRs) that included 17 peptidoglycan recognition proteins (PGRPs), 13 Gram-negative binding proteins (GNBPs), 18 scavenger receptors (SRs), 74 toll-like receptors (TLRs), and 89 C-type lectins (CLTs). Altogether, the high-quality transcriptome obtained data will offer valuable insights for further investigations into U. unicinctus innate immune response, laying the foundation for subsequent molecular biology studies and aquaculture
Novel Insight into the Synergistic Mechanism for Pd and Rh Promoting the Hydro-Defluorination of 4-Fluorophenol over Bimetallic Rh-Pd/C Catalysts
No full textThis study explores the synergistic effect between the Rh and Pd of bimetallic Rh-Pd/C catalysts for the catalytic hydro-defluorination (HDF) of 4-fluorophenol (4-FP). It was found that 4-FP could not be efficiently hydro-defluorinated over 6% Pd/C and 6% Rh/C due to the inherent properties of Pd and Rh species in the dissociation of H-2 and the activation of C-F bonds. Compared with 6% Pd/C and 6% Rh/C, bimetallic Rh-Pd/C catalysts, especially 1% Rh-5% Pd/C, exhibited much higher catalytic activity in the HDF of 4-FP, suggesting that the synergistic effect between the Rh and Pd of the catalyst was much more positive. Catalyst characterizations (BET, XRD, TEM, and XPS) were introduced to clarify the mechanism for the synergistic effect between the Rh and Pd of the catalyst in the HDF reaction and revealed that it was mainly attributed to the bifunctional mechanism: Pd species were favorable for the dissociation of H-2, and Rh species were beneficial to the activation of C-F bonds in the HDF reaction. Meanwhile, the interaction between Rh and Pd species enabled Rh and Pd to exhibit a more positive synergistic effect, which promoted the migration of atomic H* from Pd to Rh species and thus enhanced the HDF of 4-FP. Furthermore, 1% Rh-5% Pd/C prepared using 20-40 equiv NaBH4 exhibited the best performance in the catalytic HDF of 4-FP. Catalysis characterizations suggested that appropriate Rh3+/Rh-0 and Pd2+/Pd-0 ratios were beneficial to the dissociation of H-2 and the activation of C-F bonds, which caused the more positive synergistic effect between the Rh and Pd of Rh-Pd/C in the HDF reaction. This work offers a valuable strategy for enhancing the performance of catalytic HDF catalysts via promoting synergistic effects
Deficit irrigation of reclaimed water relieves oat drought stress while controlling the risk of PAEs pollution in microplastics-polluted soil
No full textReclaimed water irrigation has emerged as a critical alternative in agricultural regions facing water scarcity. However, soil pollution with microplastics (MPs) greatly increases the exposure risk and toxic effects of reclaimed water contaminations, such as phthalate esters (PAEs). A field experiment consisting of soil column pots evaluated the feasibility of using PAEs-contaminated water to irrigate oats (Avena sativa L.) in drought seasons. Three irrigation regimens based on soil matric potential thresholds (-10 kPa, -30 kPa, -50 kPa) explored the impact of PAE-contaminated water on oat physiology and environmental pollution in soil with and without MPs contamination. The results showed that treating oats at the SMP of -30 kPa boosted shoot biomass by 3.1%-14.0% compared to the drought condition at -50 kPa, and the root biomass of oats was significantly increased. The physiological metrics of oats indicated that irrigation at -50 kPa induced drought stress and oxidative damage in oats, particularly during the milk stage. Different irrigation treatments influenced the accumulation of PAEs in plants, soil, and leachate. The ratios of leachate to irrigation water in -10 kPa treatment with and without MPs addition were 1.18% and 4.48%, respectively, which aggravated the accumulation of pollutants in deep soil layers and may cause groundwater pollution. MPs pollution in soil increased the content of PAEs in the harvested oats and reduced the transport and accumulation of PAEs in deep soil layers (20-50 cm) and leachate. The coupling of PAEs in irrigation water with soil MPs pollution may exacerbate plant damage. However, the damage can be minimized under the scheduled irrigation at -30 kPa which could balance crop yield and potential risks
Evidence of nitrogen inputs affecting soil nitrogen purification by mediating root exudates of salt marsh plants
No full textSalt marsh has an important 'purification' role in coastal ecosystems by removing excess nitrogen that could otherwise harm aquatic life and reduce water quality. Recent studies suggest that salt marsh root exudates might be the 'control centre' for nitrogen transformation, but empirical evidence is lacking. Here we sought to estimate the direction and magnitude of nitrogen purification by salt marsh root exudates and gain a mechanistic understanding of the biogeochemical transformation pathway(s). To achieve this, we used a laboratory incubation to quantify both the root exudates and soil nitrogen purification rates, in addition to the enzyme activities and functional genes under Phragmites australis populations with different nitrogen forms addition (NO3-, NH4+ and urea). We found that NO3- and urea addition significantly stimulate P. australis root exudation of total acids, amino acids, total sugars and total organic carbon, while NH4+ addition only significantly increased total acids, amino acids and total phenol exudation. High total sugars, amino acids and total organic carbon concentrations enlarged nitrogen purification potential by stimulating the nitrogen purifying bacterial activities (including enzyme activities and related genes expression). Potential denitrification rates were not significantly elevated under NH4+ addition in comparison to NO3- and urea addition, which should be ascribed to total phenol self-toxicity and selective inhibition. Further, urea addition stimulated urease and protease activities with providing more NH4+ and NO2- substrates for elevated anaerobic ammonium oxidation rates among the nitrogen addition treatments. Overall, this study revealed that exogenous nitrogen could increase the nitrogen purification-associated bacterial activity through accelerating the root exudate release, which could stimulate the activity of nitrogen transformation, and then improve the nitrogen removal capacity in salt marsh
High-redox-capacity solid contact based on ferrocenyl self-assembled monolayer functionalized macroporous gold for an all-solid-state carbonate-selective electrode
No full textSolid-contact ion-selective electrodes (ISEs) are a promising tool for direct detection of CO32- activity/concen-tration in seawater. Herein, a stable solid-contact CO32--ISE was fabricated based on ferrocenyl self-assembled monolayer (SAM) functionalized macroporous gold (m-PG). Instead of the commonly used planar electrode, the m-PG film, prepared by using an electrochemical self-templating method involving the gold electrodeposition and hydrogen bubbling generation, is used as the conductive substrate. The redox capacity of the ferrocenyl SAM on the m-PG film is much larger than that on the planar Au electrode, due to the high surface area and good conductivity of m-PG. The solid-contact CO32--ISE based on ferrocenyl SAM modified m-PG shows a Nernstian potential response in the activity range from 2.6 x 10-5 to 5.3 x 10-4 M with a slope of 28.3 +/- 0.4 mV/dec and a detection limit of 1.1 x 10-5 M. The proposed electrode also exhibits a good electrode-to-electrode reproduc-ibility with a standard variation of the standard potential (E0) of 1.5 mV (n = 7), an improved potential stability and a long lifetime up to at least 120 days. The strategy for electrode substrate transformation from planar gold substrate to porous gold substrate provides an alternative way to improve the redox capacities of ferrocenyl SAMs for preparing the stable and reliable solid-contact ISEs
Functional analyses of TRAF6 gene in Argopecten scallops
No full textThe tumor necrosis factor (TNF) receptor-associated factor (TRAF) family has been reported to be involved in many immune pathways. In a previous study, we identified 5 TRAF genes, including TRAF2, 3, 4, 6, and 7, in the bay scallop (Argopecten irradians, Air) and the Peruvian scallop (Argopecten purpuratus, Apu). Since TRAF6 is a key molecular link in the TNF superfamily, we conducted a series of studies targeting the TRAF6 gene in the Air and Apu scallops as well as their hybrid progeny, Aip (Air 9 x Apu d) and Api (Apu 9 x Air d). Subcellular localization assay showed that the Air-, Aip-, and Api-TRAF6 were widely distributed in the cytoplasm of the human embryonic kidney cell line (HEK293T). Additionally, dual-luciferase reporter assay revealed that among TRAF3, TRAF4, and TRAF6, only the overexpression of TRAF6 significantly activated NF-kappa B activity in the HEK293T cells in a dose-dependent manner. These results suggest a crucial role of TRAF6 in the immune response in Argopecten scallops. To investigate the specific immune mechanism of TRAF6 in Argopecten scallops, we conducted TRAF6 knockdown using RNA interference. Transcriptomic analyses of the TRAF6 RNAi and control groups identified 1194, 2403, and 1099 differentially expressed genes (DEGs) in the Air, Aip, and Api scallops, respectively. KEGG enrichment analyses revealed that these DEGs were primarily enriched in transport and catabolism, amino acid metabolism, peroxisome, lysosome, and phagosome pathways. Expression profiles of 28 key DEGs were confirmed by qRT-PCR assays. The results of this study may provide insights into the immune mechanisms of TRAF in Argopecten scallops and ultimately benefit scallop breeding
Research on Automatic Microalgae Detection System Based on Deep Learning
No full textObjective The scale of microalgae farming industry is huge. During farming, it is easy for microalgae to be affected by miscellaneous bacteria and other contaminants. Because of that, periodic test is necessary to ensure the growth of microalgae. Present microscopy imaging and spectral analysis methods have higher requirements for experiment personnel, equipment and sites, for which it is unable to achieve real-time portable detection. For the purpose of real-time portable microalgae detection, a real-time microalgae detection system of low detection requirement and fast detection speed is needed. Methods This study has developed a microalgae detection system based on deep learning. A microscopy imaging device based on bright field was constructed. With imaged captured from the device, a neural network based on YOLOv3 was trained and deployed on microcomputer, thus realizing real-time portable microalgae detection. This study has also improved the feature extraction network by introducing cross-region residual connection and attention mechanism and replacing optimizer with Adam optimizer using multistage and multimethod strategy. Results With cross-region residual connection, the mAP value reached 0.92. Compared with manual result, the detection error was 2.47%. Conclusion The system could achieve real-time portable microalgae detection and provide relatively accurate detection result, so it can be applied to periodic test in microalgae farming
Distribution, sources, and eco-risk of Current-Use Pesticides (CUPs) in the coastal waters of the northern Shandong Peninsula, China
No full textThis study investigated the spatial distributions and seasonal variations of 19 CUPs in the coastal areas of the Shandong Peninsula and its surrounding rivers and assessed their ecological risk. In freshwater and seawater, insecticides (chlorpyrifos, methoxychlor, and pyridaben), as well as fungicides (fenarimol) and herbicides (dichlobenil) were the main pollutants (Detection Frequency: 100 %). Spatially, during winter, the regional pollution levels of Sigma(19)CUPs in seawater showed a trend of Laizhou Bay (LZB, mean:4.13 ng L-1) > Yellow River Estuary (YRE, mean:2.57 ngL(-1)) > Bohai Bay (BHB, mean:2.21 ng L-1) > Yanwei Area (YWA, mean:1.94 ng L-1). The similarities of major substances between rivers and the marine environment suggest that river discharge is the main source of CUPs pollution in coastal areas. In summer, CUPs in rivers posed a high risk. In winter, the risk significantly decreased, indicating a moderate overall risk. Seawater exhibited a low risk in winter
Advances in peptide-based drug delivery systems
No full textDrug delivery systems (DDSs) are designed to deliver drugs to their specific targets to minimize their toxic effects and improve their susceptibility to clearance during targeted transport. Peptides have high affinity, low immunogenicity, simple amino acid composition, and adjustable molecular size; therefore, most peptides can be coupled to drugs via linkers to form peptide-drug conjugates (PDCs) and act as active pro-drugs. PDCs are widely thought to be promising DDSs, given their ability to improve drug bio-compatibility and physiological stability. Peptide-based DDSs are often used to deliver therapeutic substances such as anti-cancer drugs and nucleic acid-based drugs, which not only slow the degradation rate of drugs in vivo but also ensure the drug concentration at the targeted site and prolong the half-life of drugs in vivo. This article provides an profile of the advancements and future development in functional peptide-based DDSs both domestically and internationally in recent years, in the expectation of achieving targeted drug delivery incorporating functional peptides and taking full advantage of synergistic effects