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Volume 38 ， Issue 3 ， 2020
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- Abstract：Using observations in an applied cruise of the submersible Jiaolong, water characteristics, geostrophic transport, and turbulent mixing in abyssal and hadal zones of the southern Yap Trench were studied. The spatial structures of deep water show that the abyssal water is cold, saline, and oxygen rich. The hadal water has very small changes in potential temperature and potential density, and a little decrease in salinity and obvious decrease in oxygen. The isotherm, isopycnal, and isohaline are depressed in abyss over the central trench. The turbulent mixing is enhanced in the near-bottom zone and the hadal water on the trench slope, especially at the steep slope, the dissipation rate and diffusivity is strong, which weakens the stratification. The geostrophic flows move southward in the western region of the trench and northward in the eastern region, indicating cyclonic circulation. In the central region of the trench, the water transport is ~1.74 Sv southward. In the hadal zone, the northward and southward transports are balanced. Our analysis suggests that the abyssal water in the southern Yap Trench is from Lower Circumpolar Water (LCPW) and the hadal water seems to be of the isolated local water rather than LCPW.Keywords：Yap Trench;abyssal and hadal;the submersible Jiaolong;diapycnal mixing;geostrophic flows6|1|3Updated：2023-05-19
- Abstract：The concentrations of dissolved monosaccharides (MCHO), polysaccharides (PCHO), and total carbohydrates (TCHO) in the seawater samples collected from the north of the Yap Trench in the western Pacific Ocean were measured by 2, 4, 6-tripyridine-s-triazine (TPTZ) spectrophotometry method. The results show that the concentrations of MCHO, PCHO, and TCHO ranged from 4.6 to 22.1 μmol C/L, 3.5 to 27.3 μmol C/L, and 13.8 to 36.3 μmol C/L, respectively. In different sampling stations, the concentrations of MCHO, PCHO, and TCHO with water depth showed complex variation patterns. In the study area, the maximum concentrations of MCHO, PCHO, and TCHO occurred in the euphotic layer and the minimum concentrations occurred in mesopelagic seawater layer. Generally, the concentrations of MCHO, PCHO, and TCHO decreased with water depth from the euphotic layer to the hadal zone. The average value of PCHO/TCHO was higher than the average value of MCHO/TCHO, indicating that PCHO was the main component of TCHO in north of the Yap Trench.Keywords：Yap Trench;abyss;hadal zone;monosaccharide;polysaccharide4|1|1Updated：2023-05-19
- Abstract：Knowledge about organic carbon loadings (ratio of sedimentary organic carbon (SOC) content to specific surface area (SSA)) and the fate of organic carbon (OC) is critical to understand the marine carbon cycle. We investigated the variations in the patterns of OC loadings and the preservation capacities of sedimentary OC in the Yap Trench and other marine environments. The average OC loading in sediment cores from various marine environments decreases with increasing water depth at a rate of ~0.06 mg OC/(m2·km) (R2=0.23, P < 0.01). Distinct low OC loadings (0.09±0.04 mg OC/m2) were observed in the Yap Trench, with the lowest values as ~0.02 mg OC/m2. A further comparative analysis indicated that OC/SSA=0.2 mg OC/m2 is a good indicator to distinguish between oxic deep-sea regions and suboxic energetic deltaic areas. Regression analysis between OC loading and bulk carbon isotope compositions indicates that marine OC (δ13C ~-20.4‰ to -18.6‰) dominates the lost OC within the Yap Trench and does not differ from that of the abyssal zone. In contrast, terrestrial OC with δ13C values of approximately -27.4‰ to -20.5‰ was the major source of remineralized OC in the sublittoral zone. The ratios of OC loadings in the bottom layer relative to those in the top layers of sediment cores indicate that the preservation capacities of hadal trenches are much lower than those of other environments, and only approximately 30% of the SOC deposited in hadal trenches is finally buried. The value is equivalent to 0.066% of the primary production-derived OC and much lower than the global ocean average (~0.3%). Overall, the hadal zone exhibits the lowest OC loading and preservation capacity of SOC of the different marine environments investigated, despite the occurrence of a notable funneling effect.Keywords：Yap Trench;hadal zone;organic carbon loading;specific surface area;preservation capacity6|1|2Updated：2023-05-19
- Abstract：In this study, cored sediment samples collected by the Jiaolong Submersible at 6 779 m depth from the hadal zone of the Yap Trench in May 2016 were sliced in 1-cm interval from top to bottom, and lipids in each sediment layer were quantitatively and qualitatively analyzed. The vertical distribution profiles of the lipids in the sediment sample, their main existing forms, and their possible sources were investigated. The results show that the concentration of lipid in the surface sediment was the highest with the carbon number from 12 to 27, dominated by medium and short-chain lipids. The total concentration of fatty acids in surface sediment was much higher than those in the offshore and deep-sea areas, being up to 325.77 μg/g due to the funnel effect caused by the "V" terrain of the trench. Fatty acid 18:0 was the most abundant lipids in the sediment sample. Abnormal high concentrations of fatty acid 18:1ω7 and alkanes indicated the existence of hydrothermal fluids in the study area. In addition, saturated fatty acids and monounsaturated fatty acids existed mainly in free form, and polyunsaturated fatty acids existed mainly in bound form. Most of the alkanes were in bound form, and their major source was autochthounous input. The carbon number of alcohols in the sediment sample ranged from 12 to 20, mainly existed in bound form. The source of fatty acids was mainly autochthonous input, and the neutral lipids had both marine and terrestrial origin. This is the first study of lipids in hadal sediment of the Yap Trench. The results will promote deeper understanding of organic carbon cycle in marine environment.Keywords：hadal zone;the Yap Trench;lipids;fatty acids;sediment5|2|4Updated：2023-05-19
- Abstract：Two sediment cores were retrieved in the hadal zone of the Yap Trench, and their concentrations of six major elements Mg, Al, Ca, Ti, Mn and Fe and nine trace elements Sr, Ba, Pb, V, Cr, Co, Ni, Cu and Zn were determined in inductively coupled plasma atomic emission spectrometry (ICP-AES). According to the vertical distribution profiles of the 15 elements, the correlation of their concentrations, the ratios of Ni/Co, V/Cr, Fe/Al, and Ti/Al, and morphological characteristics of the sediment samples, the implications of the depositional environment and the sediment provenance were analyzed. The results show that the ratio of Ni/Co in all depths of the two sediment cores were below 5, and the ratio of V/Cr were lower than 2, indicating that the depositional environment of the hadal zone in the trench was oxidative and might have inflow of the Antarctic bottom oxygen-rich water. The sediment samples on the eastern side of the trench were siliceous mud mainly composed of diatoms, radiolarian, and sponge needles from surface to deep layer. The vertical profile of the elements, the concentration of TOC and the fossil record indicated that the sediment sample from station Dive113 was well mixed from surface to bottom layer. Based on the correlation of concentrations of the elements, the morphological characteristics of the sediment, and the ratios of Fe/Al and Ti/Al, we inferred that the sediment in the hadal zone of the trench had terrestrial, volcanic, biological, and authigenic sources. Major source of the sediment in the eastern side of the trench were terrestrial; whereas the sediment in the western side of the trench received more volcaniclastic input.Keywords：Yap Trench;hadal zone;Jiaolong submersible;sediment metal elements;sedimentary environment4|1|6Updated：2023-05-19
- Abstract：Magnetic minerals in marine sediments are often masked by the primary natural remanent magnetization and material source signals. In order to understand sedimentary environment and sources of sediments in the abyss, we studied 126 samples of five bottom surface cores collected by the Jiaolong Submersible at 4 000-7 000 m in depth during the third stage of the China's 38th Ocean Voyage. The magnetic properties of the sediments were analyzed using Thermosusceptibility (k-T) curves and Day plot. The results show that the magnetic minerals in the sediments of the Yap Trench are mainly maghemite, and the overall magnetic and soft magnetic properties were strong. The magnetic particles of sediments are dominated by pseudo single domains (PSD) grains. The main source of sediment is locally-derived basalt debris and volcanic debris, and the process of sedimentation is gravity-like flow deposition.Keywords：magnetic property;material resource;hadal sediment;Yap4|0|2Updated：2023-05-19
Special Section on Yap Trench
- Abstract：Interaction between mesoscale perturbations of sea surface temperature (SSTmeso) and wind stress (WSmeso) has great influences on the ocean upwelling system and turbulent mixing in the atmospheric boundary layer. Using daily Quik-SCAT wind speed data and AMSR-E SST data, SSTmeso and WSmeso fields in the western coast of South America are extracted by using a locally weighted regression method (LOESS). The spatial patterns of SSTmeso and WSmeso indicate strong mesoscale SST-wind stress coupling in the region. The coupling coefficient between SSTmeso and WSmeso is about 0.009 5 N/(m2·℃) in winter and 0.008 2 N/ (m2·℃) in summer. Based on mesoscale coupling relationships, the mesoscale perturbations of wind stress divergence (Div(WSmeso)) and curl (Curl (WSmeso)) can be obtained from the SST gradient perturbations, which can be further used to derive wind stress vector perturbations using the Tikhonov regularization method. The computational examples are presented in the western coast of South America and the patterns of the reconstructed WSmeso are highly consistent with SSTmeso, but the amplitude can be underestimated significantly. By matching the spatially averaged maximum standard deviations of reconstructed WSmeso magnitude and observations, a reasonable magnitude of WSmeso can be obtained when a rescaling factor of 2.2 is used. As current ocean models forced by prescribed wind cannot adequately capture the mesoscale wind stress response, the empirical wind stress perturbation model developed in this study can be used to take into account the feedback effects of the mesoscale wind stress-SST coupling in ocean modeling. Further applications are discussed for taking into account the feedback effects of the mesoscale coupling in largescale climate models and the uncoupled ocean models.Keywords：mesoscale air-sea coupling;Tikhonov's regularization method;western coast of South America4|1|0Updated：2023-05-19
- Abstract：Internal solitary waves (ISWs) always happen in marginal seas, where stable stratification exists. ISWs may carry large energy when they propagate and affect marine engineering constructions such as marine drilling platforms. Previous studies, including a large number of mooring observations and laboratory experiments, show the speed of ISWs will change when they pass by shelf slopes. Korteweg-de Vries (KdV) theory explain this phenomenon. In the paper, we use a laboratory experiment and a numerical model experiment to verify this theory. In the laboratory experiment, we injected two layers of water of different densities in a tank to simulate marine stratification and make ISWs. We use a CCD camera to record the whole process. The camera can take 16 photos per second. In the numerical experiment, we input the same original conditions as the laboratory one. The results of 18 different original conditions show the dimensionless factor δ plays a key role in deciding the amplitudes and shapes of ISWs. The main conclusion also contains that small-amplitude waves match well with KdV theory while mKdV is better for largeamplitude waves. Whether the laboratory experiment or numerical experiment shows results with a high agreement. In future studies, we may use a numerical model with higher resolution to get analysis about phase speed and energy of ISWs.Keywords：internal solitary waves;shelf-slope;laboratory experiment;numerical modeling4|1|3Updated：2023-05-19
- Abstract：Since coastal areas have highly dynamic nature and are one of the most beneficial regions of civilizations, it is of great significance to understand their characteristics and behavior. Changes in shorelines in the form of accretion and erosion can leave devastating effects on businesses and cities located along the shore. In this study, we statistically calculated the tendency of shoreline changes by processing and analyzing historical satellite images of Boushehr Province, Iran. Results show that these shores have experienced both sedimentation and erosion in the past 30 years. Net shoreline movement presents more than 350 m of erosion and 650 m of accretion, which are corresponded to change rates of almost 12 and 22 m/a, respectively. Statistics of shoreline changes are calculated from regression methods including end point rate, linear regression rate, weighted linear regression, and least median of squares. The best-performed method is applied to predict the shoreline position in 2050 and 2100. Potential locations of excessive changes are identified for the predicted shorelines, which should be dealt with properly.Keywords：digital shoreline analysis system;satellite image;accretion and erosion;linear regression;sediment;Boushehr Province4|2|0Updated：2023-05-19
Physics
- Abstract：On May 24-29, 2019, a bloom occurring in Pingtan coastal areas of Fujian Province caused mass mortality of cage-cultured fish (Plectorhinchus cinctus and Pagrosomus major). During the bloom, two major causative organisms were present: Prorocentrum donghaiense (at a concentration of 1.46×107 cells/L) and an unknown naked dinoflagellate (4.58×106 cells/L). The naked dinoflagellate was isolated and cultured in this study, and its morphological features were examined using light microscopy and scanning electron microscopy. The large subunit (LSU) of the rRNA gene and the internal transcribed spacer (ITS) region of the naked dinoflagellate were also sequenced for field bloom samples and lab culture strains (PT-A and PT-B). On the basis of its morphological characteristics and molecular sequences, the unknown naked dinoflagellate was identified as Karlodinium digitatum. According to the phylogenetic analysis, the Karl. digitatum was most closely related to Karlodinium australe and Karlodinium armiger, and the three species clustered into a single clade of Karlodinium with bootstrap/posterior probability values of 95%/0.99 and 86%/0.99 inferred from LSU and ITS sequences, respectively. Karl. digitatum was first reported as Karenia digitata, a new harmful algal species bloomed in Hong Kong, China, in 1998. In present study, we gave a detailed morphological and phylogenetic description of Karl. digitatum and submitted the molecular sequences of this species to GenBank for the first time.Keywords：Karenia digitata;Karlodinium digitatum;harmful algal bloom;Ichthyotoxicity4|0|1Updated：2023-05-19
- Abstract：At present, the understanding of the dynamics of denitrifiers at different dissolved oxygen (DO) layers under organic carbon consumption within the surface sediments remains inadequate. In this study, high-throughput sequencing and quantitative PCR targeting nirS gene were used to analyze the denitrifier abundance dynamics, community composition, and structure for aerobic (DO 0.5-6.9 mg/L), hypoxic-anoxic (DO 0-0.5 mg/L), and anoxic (DO 0 mg/L) layers in surface sediments under organic carbon consumption. Based on the analysis of nirS gene abundance, the values of denitrifying bacteria decreased with organic carbon consumption at different DO layers. When the bacterial species abundance at the genus level were compared between the high-carbon and low-carbon sediments, there was significant increase in 6 out of 36, 7 out of 36 and 6 out of 36 genera respectively for the aerobic, hypoxic-anoxic and anoxic layers. On the other hand, 14 out of 36, 9 out of 36 and 15 out of 36 genera showed significant decrease in bacterial species abundance respectively for the aerobic, hypoxic-anoxic and anoxic layers. Additionally, 14 out of 36, 20 out of 36, and 15 out of 36 genera had no change in bacterial species abundance respectively for the aerobic, hypoxic-anoxic, and anoxic layers. This indicates that the carbon utilization ability of different denitrifiers on each DO layers was generally different from each other. Diversity of denitrifying bacteria also presented significant differences in different DO layers between the high- and low-carbon content sediment layers. Moreover, under the high-carbon and low-carbon content, the abundance of nirS gene showed a high peak within the hypoxic-anoxic regions, suggesting that this region might be the main distribution area for the denitrifying bacteria within the surface sediments. Furthermore, community of unique denitrifiers occurred in different DO layers and the adaptive changes of the denitrifier community followed the organic carbon consumption.Keywords：eutrophic freshwater lake;surface sediments;dissolved oxygen profiles;denitrifier;organic carbon consumption4|1|1Updated：2023-05-19
Ecology
- Abstract：The distinctive estuary hydrodynamics and nutrient input make the estuary ecosystem play a key role in lake ecosystems. The Nanfei River and Zhaohe River are two main inlets of Chaohu Lake, Anhui, East China. We selected estuaries of the two rivers as representative areas to study temporal and spatial changes of bacterial communities. In August (summer) and November (autumn) 2016 and February (winter) and May (spring) 2017, 16 water and sediment samples were collected from the estuaries. Physicochemical characteristics indicate significant differences in the nutritional status and eutrophication index of the estuaries due mainly to organic input. Examination of the number of operational taxonomic units, the diversity index, the community composition, and redundancy analysis revealed the following. First, the existence of varying degrees of seasonal differences in the distribution of almost all bacteria. In addition, the species diversity in the sediment samples was higher than that in the water samples, and the dominant species differed also among these samples. Second, a large number of unknown genera were detected, especially in the sediment samples, such as unclassified Xanthomonadales incertae sedis, unclassified Anaerolineaceae, and unclassified Alcaligenaceae. Last, TP, TN, and TOC were the main influential factors that affected the bacterial community structure.Keywords：estuary;water and sediment;bacterial diversity;bacterial community structure4|2|0Updated：2023-05-19
- Abstract：Ocean acidification (OA) affects marine biodiversity and alters the structure and function of marine populations, communities, and ecosystems. Recently, effects of OA on the behavioral responses of marine animals have been given with much attention. While many of previous studies focuses on marine fish. Evidence suggests that marine invertebrate behaviors were also be affected. In this review, we discussed the effects of CO2-driven OA on the most common behaviors studied in marine invertebrates, including settlement and habitat selection, feeding, anti-predatory, and swimming behaviors, and explored the related mechanisms behind behaviors. This review summarizes how OA affects marine invertebrate behavior, and provides new insights and highlights novel areas for future research.Keywords：carbon dioxide;global climate change;invertebrate behavior;ocean acidification (OA);pH4|2|0Updated：2023-05-19
- Abstract：Phenol is a common industrial chemical produced and transported worldwide largely. Therefore, accidental spillage of phenol in the ocean causes an increasing concern. Microalgae are promising to remove phenol from marine waters. However, temperature and light intensity are two main factors that markedly influence biodegradation in marine environments. In this study, a marine golden alga Isochrysis galbana is selected to research the removal of phenol under different temperatures (10-30℃) and light intensities (0-240 μmol/(m2·s)). The results show that the most suitable temperature and light intensity for phenol removal are 20℃ and 180 μmol/(m2·s), respectively, and 100 mg/L of phenol can be completely removed by microalga in 24 h at these conditions. I. galbana can also remove phenol under dark and low-temperature conditions. The removal of phenol by I. galbana at diverse temperatures and light intensities conform to first-order kinetics, and the process under dark conditions conform to zero-order kinetics. Thus, I. galbana can be used in the in-situ bioremediation of polluted seawater by phenol.Keywords：phenol;Isochrysis galbana;temperature;light intensity;biodegradation4|0|2Updated：2023-05-19
- Abstract：The unicellular green alga Chlamydomonas reinhardtii, a well-established model organism, has been widely used in dissecting glycerolipid metabolism in oxygenating photosynthetic organisms. In previous studies, it has been found that shunting carbon precursors from the starch synthesis pathway can lead to a 10-fold increase in TAG content as compared to the wild type, but it is unknown whether inactivation of AGPase may affect membrane lipids biosynthesis. The study aims to investigate global changes in lipid metabolism and homeostasis in the starchless mutant C. reinhardtii sta6. By utilizing an electrospray ionization/mass spectrometry (ESI/MS)-based lipidomics approach, a total of 105 membrane lipid molecules of C. reinhardtii were resolved, including 16 monogalactosyldiacylglycerol (MGDG), 16 digalactosyldiacylglycerol (DGDG), 11 phosphatidylglycerol (PG), 6 sulfoquinovosyldiacylglycerol (SQDG), 49 diacylglyceryl-N, N, N-trimethylhomoserine (DGTS), 2 phosphatidylethanolamine (PE), and 5 phosphatidylinositol (PI) molecules. The quantitative results indicated that the membrane lipid profiles were similar between the two C. reinhardtii strains grown under both low- and high-light conditions, but the cellular contents of a great number of lipids were altered in sta6 due to the defect in starch biosynthesis. Under low-light conditions, sta6 accumulated more PI, MGDG, DGDG but less amounts of DGTS as compared to WT. Under high light, sta6 cells contained higher content membrane lipids than cc-124, except for PG, which is more or less similar in both strains. Our results demonstrate that the cellular membrane lipid homeostasis underwent profound changes in the starchless mutant, and thereby its physiological impact remains to be explored.Keywords：Chlamydomonas reinhardtii;chloroplast lipidomes;extraplastidic lipidomes;electrospray ionization mass spectrometry4|0|0Updated：2023-05-19
- Abstract：Light is an important parameter in algal culturing. In this work, the effects of different light qualities on growth of the marine diatom Chaetoceros gracilis are evaluated. The cells were cultured under light quantum flux density of 60 μmol photons/(m2·s) with nine light qualities: LED red light (LR), LED blue light (LB), LED red plus LED blue light (LR+LB), LED white light (LW), fluorescent white light (FW), and combinations of LW and FW lights with increased proportions of red or blue light (FW+LR, FW+LB, LW+LR, and LW+LB). Blue light promoted the growth of C. gracilis largely. Three light qualities, FW+LR, LW+LR, and LR, resulted in the lowest growth rate. Both chlorophyll and carotenoids reached the highest level under LB and the lowest level under LR among monochromatic light sources; however, increasing of the proportion of blue or red light in the white light induced an increase of the chlorophyll and carotenoid concentrations. Light absorption ability of microalgae was critical for the growth of these organisms, as we observed a positive correlation between the extinction coefficient at different wavelengths and the specific growth rate. These findings are of importance to improve the culturing of this alga in bioreactors.Keywords：Chaetoceros gracilis;light quality;pigments;wavelength effect;mean extinction coefficients4|0|3Updated：2023-05-19
- Abstract：Growth and biochemical responses of the coenobial green alga Scenedesmus obliquus to salinity stress were monitored across different phases of growth. The alga was cultured on BG11 growth medium and subjected to 0, 30, 100, and 200 mmol/L NaCl for a period of 20 d, during which algal cultures were harvested at 4-d intervals. The salinity-induced inhibition of algal growth was accompanied with prolongation of timing of the different growth phases. The sharp and progressive salinity-induced inhibition of algal growth rate during the early phase of growth points to salt shock but moderation of inhibition at the subsequent stages of growth means algal acclimation to salinity. The concentrations of chlorophylls a and b, soluble sugars, proteins as well as those of K+ and Na+ in the alga exhibited peaks at the initiation of the exponential phase of growth, with increasing magnitude in proportion to the increase in the level of salinity. Nevertheless, whereas soluble sugars of the alga peaked at initiation of the exponential phase, starch concentration progressively increased with culture age, reaching saturation towards the stationary phase. Whereas the salinity-induced increase in soluble sugars was most evident at the early stages of growth the reverse was true for starch. The present results point to fast acclimation of S. obliquus to salt stress post a brief salt shock, utilizing soluble sugars, K+ and Na+ for osmotic adjustment. Increasing salinity from 0 to 200 mmol/L NaCl led to progressive increase in soluble sugars, proteins, K+ and Na+ concentrations of the algal cells, particularly at the early stages of growth. However, the salinity-induced increase in chlorophyll concentration approached a limit at 100 mmol/L NaCl whereas that in starch concentration was more evident at the later stages of growth.Keywords：carbohydrates;growth phase;minerals;protein;salt stress;Scenedesmus obliquus4|0|0Updated：2023-05-19
- Abstract：The mitochondrial genome (mitogenome) analysis is a significant tool for investigating the evolutionary history of metazoan animals. The family Pandalidae is a diverse caridean group containing mainly deep-sea species. Until May 30 2019, only two complete mitogenomes are available in GenBank. Here we present the complete mitogenome sequences of two deep-sea pandalid shrimps, Heterocarpus ensifer and Bitias brevis through Illumina sequencing. The mitochondrial genomes were determined to be 15 939 bp and 15 891 bp long, and both consist of 13 protein-coding genes (PCGs), 23 transfer-RNA genes (tRNAs), two ribosomal-RNA genes (rRNAs), and one control region. The nucleotide composition is biased toward adenine and thymine. Overall, the gene contents and arrangements are consistent with the pancrustacean ground pattern. The alignment of the control regions of four pandalids reveals a conserved sequence block (CSB) (104 bp in length, average GC%=29.47% and 69.23% similarity). A phylogenetic analysis based on 51 Caridea complete mitogenomes revealed that the deep-sea pandalid shrimps are situated an intermediate lineage, with a tendency to originated from those living in shallow sea area.Keywords：Pandalidae;deep sea;mitochondrial genome;gene order;phylogenetic relationships4|0|0Updated：2023-05-19
- Abstract：Marine bacterial strain Bacillus sp. CS30 exhibited high anticancer activity against Huh7.5 human liver cancer. We purified the corresponding anticancer agent by sequential acidic precipitation, methanol extraction, Sephadex LH-20 chromatography, and reversed phase high-performance liquid chromatography (RP-HPLC), then analyzed it in mass spectrometry. Based on the results of purification and mass spectrometry, we deduced that the anticancer agent was the same component as our previously purified antifungal agent surfactin CS30-2. However, to the best of our knowledge, this is the first report on the surfactin possessing both antifungal and anticancer activities. Surfactin CS30-2 was demonstrated to exhibit high anticancer activity in a dose-dependent manner against Huh7.5 liver cancer cells. Further investigation showed that surfactin CS30-2 induced the increased generation of reactive oxygen species (ROS) and severe disruption of cell membrane, thus leading to cell death. However, unlike previously reported surfactins, surfactin CS30-2 caused cancer cell death via necrosis instead of apoptosis.Keywords：Bacillus;surfactin;anticancer activity;reactive oxygen species (ROS)4|0|0Updated：2023-05-19
- Abstract：We previously demonstrated that 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) promoted the production of nitric oxide (NO) and proinflammatory cytokines by activating the mitogen-activated protein kinases (MAPK) and Janus kinase (JAK)/STAT pathways in RAW 264.7 cells, indicating good immunomodulatory activity of HACC. In this study, to further investigate the immunomodulatory mechanisms of HACC, we determined the roles of phosphatidylinositol 3-kinase (PI3K)/Akt, activating protein (AP-1) and nuclear factor kappa B (NF-κB) in HACC-induced activation of RAW 264.7 cells by the western blotting. The results suggest that HACC promoted the phosphorylation of p85 and Akt. Furthermore, c-Jun and p65 were also increased after the treatment of RAW 264.7 cells with HACC, indicating the translocation of NF-κB and AP-1 from cytoplasm to nucleus. In addition, as scanning electron microscopy (SEM) analysis shows, the cell morphology changed after HACC treatment. These findings indicate that HACC activated MAPK, JAK/STAT, and PI3K/Akt signaling pathways dependent on AP-1 and NF-κB activation in RAW 264.7 cells, ultimately leading to the increase of NO and cytokines.Keywords：hydroxypropyltrimethyl ammonium chloride chitosan;RAW 264.7 cells;PI3K/Akt pathway;nuclear factor-κB;activating protein 14|3|0Updated：2023-05-19
- Keywords：chitooligosaccharide (COS);aminourea;characterization;antifungal6|2|0Updated：2023-05-19
Biology
- Keywords：Japanese grenadier anchovy;population structure;anthropogenic factors;life-history;nuclear DNA sequences4|0|2Updated：2023-05-19
- Keywords：Crassostrea gigas;basic helix-loop-helix (bHLH);re-sequencing;single nucleotide polymorphism (SNP) shot;growth traits4|0|1Updated：2023-05-19
- Keywords：Eriocheir sinensis;cottonseed meal protein hydrolysate;growth;body composition;immunity;antioxidant4|0|3Updated：2023-05-19
- Keywords：sea cucumber;Cucumaria frondosa;physiological property;feeding behavior;nutritional condition4|0|0Updated：2023-05-19
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Aquaculture and Fisheries
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