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A new chemosymbiotic bivalve species of the genus Acharax Dall, 1908 (Bivalvia, Solemyida, Solemyidae) from the Haima cold seep of the South China Sea
No full textSolemyidae is an ancient group of protobranch bivalves that typically inhabit unusual environments, such as deep-sea chemosynthetic environments, and are symbiotic with chemoautotrophic and gill -hosted bacteria. In May 2018, a living solemyid bivalve was collected using a remotely operated vehicle at a depth of 1,390 m from the Haima cold seep in the northwestern slope of the South China Sea. Through a comprehensive taxonomic approach combining morphological observations and molecular phylogeny reconstruction of concatenated mitochondrial COI,16S rRNA and 18S rRNA gene sequences, a new species, Acharax haimaensis sp. nov. is identified and described. The discovery of this new species contributes to the diversity of known solemyids in deepsea chemosynthetic environments
Polyhydroxy steroids isolated from starfish (<i>Asterina pectinifera</i>) and their embryotoxicity
No full textMany marine organisms possess an essential capacity to produce secondary metabolites that exhibit toxic characteristics. A new polyhydroxy steroid, 24-methyl-5 alpha-cholestane-24(28)-ene-3 beta, 4 beta, 6 alpha, 7 alpha, 8, 15 beta, 16 beta, 26-octol-6-O-sodium sulphate (1) was isolated from starfish (Asterina pectinifera), along with five polar steroid compounds (2-6) that were previously identified. NMR (H-1 and C-13 NMR, H-1-H-1 COSY, HSQC, HMBC, and NOESY) and HR-ESI-MS were employed for structure elucidations. The embryotoxicity and teratogenicity of the isolated compounds were assessed using embryos of marine medaka (Oryzias melastigma). Compound 5 exhibited moderate embryotoxicity (96h-LC50: 65 mu M). [Graphical Abstract
Effects of ocean acidification and polystyrene microplastics on the oysters <i>Crassostrea gigas</i>: An integrated biomarker and metabolomic approach
No full textThe adverse impacts of microplastics (MPs) or ocean acidification (OA) on mollusks have been widely reported, however, little is known about their combined effects on mollusks. The oysters Crassostrea gigas were exposed to two sizes of polystyrene MPs with 1 x 104 particles/L (small polystyrene MPs (SPS-MPs): 6 mu m, large polystyrene MPs (LPS-MPs): 50-60 mu m) at two pH levels (7.7 and 8.1) for 14 days. The antagonistic effects between MPs and OA on oysters were mainly observed. Single SPS-MPs exposure can induce CAT enzyme activity and LPO level in gills, while LPS-MPs exposure alone can increase PGK and PEPCK gene expression in digestive glands. Ocean acidification can increase clearance rate and inhibit antioxidant enzyme activity, whereas combined exposure of OA and SPS-MPs can affect the metabolomic profile of digestive glands. This study emphasized that the potential toxic effects of MPs under the scene of climate change should be concerned
Imaging of carboxylesterase 2 expression changes in colitis and colon cancer chemotherapy via a fluorescent probe
No full textColitis is one of the important etiologies of colon cancer, but the diagnosis of early colitis and colon cancer is still a difficult problem, so it is important to use reasonable methods to achieve the diagnosis of early colitis and colon cancer. Carboxylesterase 2 (CES2) is momentous in the development of colon disease and can be used as an indicator to distinguish colitis from colon cancer. CES2 is expressed differently in colitis and colon cancer, so it has the potential to distinguish colitis from colon cancer by detecting the difference in CES2 expression. We designed a fluorescent probe Bcy-CES2 for imaging CES2 in cells and in vivo and evaluating the differences in CES2 levels in colon disease. Probe Bcy-CES2 shows good potential for in situ real -time monitoring of endogenous CES2. In addition, we found that the combination of CES2 inhibitor BNPP and cisplatin can reduce tumor chemotherapy resistance, and CES2 levels may become a new index for early diagnosis and prognosis of colon cancer
Imaging of carboxylesterase 2 expression changes in colitis and colon cancer chemotherapy via a fluorescent probe
No full textColitis is one of the important etiologies of colon cancer, but the diagnosis of early colitis and colon cancer is still a difficult problem, so it is important to use reasonable methods to achieve the diagnosis of early colitis and colon cancer. Carboxylesterase 2 (CES2) is momentous in the development of colon disease and can be used as an indicator to distinguish colitis from colon cancer. CES2 is expressed differently in colitis and colon cancer, so it has the potential to distinguish colitis from colon cancer by detecting the difference in CES2 expression. We designed a fluorescent probe Bcy-CES2 for imaging CES2 in cells and in vivo and evaluating the differences in CES2 levels in colon disease. Probe Bcy-CES2 shows good potential for in situ real -time monitoring of endogenous CES2. In addition, we found that the combination of CES2 inhibitor BNPP and cisplatin can reduce tumor chemotherapy resistance, and CES2 levels may become a new index for early diagnosis and prognosis of colon cancer
The characteristics of soil salinization effects on nitrogen mineralization and nitrification in upland fields
No full textThe influence of soil salinization on nitrogen (N) transformation is largely unknown, which impedes the reasonable management of N in saline fields. A comprehensive meta-analysis was thus conducted to evaluate the effects of salinity and relative soil physicochemical properties on net N mineralization and nitrification in upland soils. Results showed that effects of salinity on the net-N mineralization rate (Min) and nitrification rate (Nit) changed with the salinity level and incubation time. Generally, the inhibitory effect of salt on Min and Nit decreased gradually with incubation time. At 14-16 days of soil incubation, significant stimulatory effects on Min were observed in middle-level (ECe: 12-16 dS m(-1)) and high-level (ECe >16 dS m(-1)) saline soils, and on Nit in low-level (ECe: 4-12 dS m(-1)) saline soils. Regression analysis revealed that the effects of soil organic carbon (SOC), total N (TN), C/N, pH, and clay content on Min and Nit were closely related to salinity levels. Nit at 5-7 days of soil incubation first enhanced and then decreased with C/N increase, and the threshold value was 34.7. The effect of pH on Nit changed with salinity levels, and shifted from stimulation to inhibition with increasing pH. Min at 5-7 days of soil incubation in middle-level group first increased with increasing pH, and decreased when pH was higher than 8.1. Salinization deeply affected soil properties, which further influenced N turnover via alteration of the availability of substrates and microbial biomass and activities. Our findings suggest that the influence of salinity on soil N turnover closely related with salinity level, and salinity level should be considered fully when optimizing N management in saline upland fields
Rapid antibiotic screening based on E. coli apoptosis using a potentiometric sensor array
No full textPhenotypic antimicrobial susceptibility testing enables reliable antibiotic screening but requires multiple strategies to identify each phenotypic change induced by different bactericidal mechanisms. Bacteria apoptosis with typical phenotypic features has never been explored for antibiotic screening. Herein, we developed an antibiotic screening method based on the measurement of antibiotic-induced phosphatidylserine (PS) exposure of apoptotic bacteria. Phosphatidylserine externalization of E. coli that can be widely used as an apoptosis marker for antibiotics with different antibacterial mechanisms was explored. A positively charged PS-binding peptide was immobilized on magnetic beads (MBs) to recognize and capture apoptotic E. coli with PS externalization. Apoptotic E. coli binding led to the charge or charge density change of MBs-peptide, resulting in a potential change on a magneto-controlled polymeric membrane potentiometric sensor. Based on the detection of apoptotic E. coli killed by antibiotics, antibiotic screening for different classes of antibiotics and silver nanoparticles was achieved within 1.5 h using a potentiometric sensor array. This approach enables sensitive, general, and timesaving antibiotic screening, and may open up a new path for antibiotic susceptibility testing
Analysis of the evolution, losses and gains of tidal wetlands in the Bohai Rim based on image data cube
No full textUnder the influence of challenges posed by both human and natural factors, tidal wetlands in the Bohai Rim have been confronting severe threats. It is imperative to comprehend the evolution, as well as the losses and gains of tidal wetlands in the Bohai Rim, for effective coastal management and planning. However, the dynamic fluctuations in the losses and gains of tidal wetlands in this region are frequently overlooked. In this study, employing image data cubes and frequency method, we systematically monitored tidal wetlands in the Bohai Rim spanning the period from 1986 to 2022. Additionally, we performed an exhaustive analysis of the evolution, losses, and gains of tidal wetlands within the provinces and municipality surrounding the Bohai Rim, as well as a detailed analysis of typical areas. This study unveiled three key findings. Firstly, tidal wetlands in Liaoning, Hebei, Tianjin, and Shandong had experienced significant declines of 42%, 66.3%, 71.08% and 60.52% from 1986 to 2022, respectively; they had contracted spatially and changed from a contiguous complete distribution to a scattered fragmented distribution. Secondly, reclamation and erosion had led to the loss of tidal wetlands, while sedimentation had led to the gain of tidal wetlands. The loss area of tidal wetlands caused by reclamation and erosion, as well as the gain area of tidal wetlands caused by sedimentation, had exhibited fluctuating changes from 1986 to 2022. Finally, the area of tidal wetlands in the Liaohe River Delta, Tianjin Port, and Yellow River Delta had decreased by 46.48%, 74.96% and 22.36% from 1986 to 2022, respectively; and tidal wetlands in these three typical areas had spatially contracted. Our findings offer a fresh perspective and a solid scientific foundation for the effective management and strategic planning of tidal wetlands in the Bohai Rim region
Analysis of Carbon Flux Characteristics in Saline-Alkali Soil Under Global Warming
No full textThe carbon cycle of saline-alkali ecosystems will be affected to some extent in the context of future global warming. Therefore, we investigated the net ecosystem exchange (NEE) of three typical crops (wheat, maize and soybean) in the saline-alkaline land of the Yellow River Delta. To further investigate CO2 fluxes, NEE was decomposed into gross primary productivity (GPP) and ecosystem respiration (Re). In terms of seasonal variation, wheat and soybean were carbon sources in the early and late growth periods, and carbon sinks in the rest of the period, whereas maize was a carbon sink in the majority of the period, and maize had good carbon sink potential. The cumulative NEE during the growth periods for wheat, maize, and soybean were 414.86, 258.24 and 228.92 g cm-2, respectively, and the daily variation showed that the peak NEE values for the three crops preceded the peak values of both GPP and ecosystem respiration, occurring approximately at 12:00 a.m. In the correlation analysis, NEE and GPP of the three crops were well correlated with photosynthetic photon flux density and net radiation, whereas Re was significantly correlated with air temperature. Through a comparative analysis of CO2 fluxes within various agricultural ecosystems, our findings indicated that wheat demonstrated moderate carbon sequestration capabilities, whereas maize and soybean exhibited strong carbon sink characteristics. Notably, saline-alkali crops exhibited lower Re, whereas GPP levels remained at a moderate range. Therefore, under the global warming trend, the respiration of saline crops and soils will be affected and may change the original carbon sink into a carbon source. Hence, implementing suitable measures targeting saline-alkali areas, such as the establishment of an effective crop rotation system and the enhance saline-alkali land conditions, can reduce emissions of greenhouse gases, thus reducing the pressure of global warming and maintaining a stable carbon cycle in saline-alkali land
Ship Emissions as the Largest Contributor to Coastal Atmospheric Black Carbon at a Receptor Island in Southern China
No full textAtmospheric black carbon (BC) over coastal regions poses a threat in terms of both climate change and human health. However, the provenance of aerosol BC, particularly its subfractions (char-BC and soot-BC, which have different physicochemical properties), is poorly constrained. Here, we apportioned the sources of char-BC and soot-BC in year-round PM2.5 samples from a coastal receptor island off southern China. Char-BC dominated, accounting for 88.6 +/- 13.2% of the total BC. The two BC subfractions exhibited distinct seasonal variation patterns, which may be attributed to differences in their sources and hydrophilicity. Combustion of liquid fossil fuels, including bunker fuel, diesel, and gasoline, contributed more highly to soot-BC (71.4%) than to char-BC (53.9%). Conversely, combustion of solid fuels, including biomass and coal, contributed more highly to char-BC (44.6%) than to soot-BC (6.7%). Bunker fuel combustion, the dominant portion of ship emissions, was the largest contributor to total BC (46.0%), char-BC (45.2%), and soot-BC (56.4%). This indicates that marine ship emissions, rather than land-based sources including biomass and coal combustion, were the dominant source of atmospheric BC in coastal areas, highlighting the importance of controlling maritime ship emissions