Institutional Repository of South China Sea Institute of Oceanology, CAS
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REPLY TO JOHNSON ET AL.: Functionally active cryptophyte cell membrane and cytoplasm indicate intact symbionts within Mesodinium
No full textBNIP3, a cell pro-apoptotic protein, involved in response to viral infection in orange spotted grouper, Epinephelus coioides
No full textBNIP3 is a kind of BH3-only protein that induces both cell death and autophagy. Here, a BNIP3 gene (EcBNIP3) was identified from orange spotted grouper, Epinephelus coioides. EcBNIP3 possessed 236 amino acids residues, contained a conservative BNIP3 domain and a transmembrane region. Besides, EcBNIP3 expressed at a relative high level in heart and spleen. EcBNIP3 transcript was up-regulated after SGIV infection in vitro. Subcellular localization analysis revealed that EcBNIP3 was predominantly localized in the cytoplasm and co-localized with mitochondria. In addition, overexpression EcBNIP3 accelerated SGIV infection induced cell death but inhibited viral genes transcription. Taken together, these results provided new evidence that fish BNIP3 might involved in response to virus infection. (C) 2017 Published by Elsevier Ltd
Metabolic and fitness determinants for in vitro growth and intestinal colonization of the bacterial pathogen Campylobacter jejuni
No full textCampylobacter jejuni is one of the leading infectious causes of food-borne illness around the world. Its ability to persistently colonize the intestinal tract of a broad range of hosts, including food-producing animals, is central to its epidemiology since most infections are due to the consumption of contaminated food products. Using a highly saturated transposon insertion library combined with next-generation sequencing and a mouse model of infection, we have carried out a comprehensive genome-wide analysis of the fitness determinants for growth in vitro and in vivo of a highly pathogenic strain of C. jejuni. A comparison of the C. jejuni requirements to colonize the mouse intestine with those necessary to grow in different culture media in vitro, combined with isotopologue profiling and metabolic flow analysis, allowed us to identify its metabolic requirements to establish infection, including the ability to acquire certain nutrients, metabolize specific substrates, or maintain intracellular ion homeostasis. This comprehensive analysis has identified metabolic pathways that could provide the basis for the development of novel strategies to prevent C. jejuni colonization of food-producing animals or to treat human infections
Alteration of Diastereoisomeric and Enantiomeric Profiles of Hexabromocyclododecanes (HBCDs) in Adult Chicken Tissues, Eggs, and Hatchling Chickens
No full textThe concentrations and enantiomer fractions (EFs) of alpha-, beta-, and gamma-hexabromocyclododecanes (HBCDs) were measured in chicken diet sources (soil and chicken feed), home-raised adult chicken (Gallus domesticus) tissues, eggs during incubation, and hatchling chicken tissues. HBCD concentrations were not detected-0.69 ng/g dry weight (dw) and 25.6-48.4 ng/g dw in chicken feed and soil, respectively. HBCDs were detected in all adult chicken tissues, except the brain, at median levels of 13.1-44.0 ng/g lipid weight (lw). The proportions of alpha-HBCD in total HBCDs increased from 51% in soil to more than 87% in adult chicken tissues. The accumulation ratios (ARs) of alpha-HBCD from diet to adult chicken tissues were 4.27 for liver, 11.2 for fat, and 7.64-12.9 for other tissues, respectively. The AR and carry-over rate (COR) of alpha-HBCD from diet to eggs were 22.4 and 0.226, respectively. The concentrations of alpha-HBCD in hatchling chicken liver (median: 35.4 ng/g lw) were significantly lower than those in hatchling chicken pectoral muscle (median: 130 ng/g lw). The EFs of alpha-HBCD decreased from soil to adult chicken tissues and from eggs to hatchling chicken liver. Meanwhile, the EFs of gamma-HBCD increased from soil to adult chicken tissues. These results indicate the preferential enrichment of (-)-alpha-HBCD and (+)-gamma-HBCD in chickens. The alteration of diastereoisomeric and enantiomeric patterns of HBCDs might be influenced by the different absorption and elimination rates of the six HBCD enantiomers as well as variations in HBCD metabolism in chickens
Distribution of reactive aluminum under the influence of mesoscale eddies in the western South China Sea
No full textTo understand the distribution of aluminum (Al) under the influence of mesocale eddies in the western South China Sea (SCS), sea level anomaly, geostrophic current, environmental parameters and reactive Al were investigated in the western SCS in August 2013. The highest reactive Al concentration ((180 +/- 64) nmol/L) was observed in the surface waters, indicating a substantial atmospheric input. Vertically, the reactive Al decreased from the surface high concentration to the subsurface minima at the depth of chlorophyll a (Chl a) maxima and then increased again with depth at most of the stations. The average concentration of reactive Al in the upper 100 m water column was significantly lower in the cyclonic eddy ((137 +/- 6) nmol/L) as compared with that in the noneddy waters ((180 +/- 21) nmol/L). By contrast, the average concentrations of Chl a and silicate in the upper 100 m water column were higher in the cyclonic eddy and lower in the anticyclonic eddy. There was a significant negative correlation between the average concentrations of reactive Al and Chl a in the upper 100 m water column. The vertical distribution of reactive Al and the negative correlation between reactive Al and Chl a both suggest that the reactive Al in the upper water column was significantly influenced by biological removal processes. Our results indicate that mesoscale eddies could regulate the distribution of reactive Al by influencing the primary production and phytoplankton community structure in the western SCS
Antioxidant activity against H2O2-induced cytotoxicity of the ethanol extract and compounds from Pyrola decorate leaves
No full textContext: The leaves of Pyrola decorate H. Andr (Pyrolaceae), known as Luxiancao, have long been used for treating kidney deficiency, gastric haemorrhage and rheumatic arthritic diseases in traditional Chinese medicine. Objective: The phytochemicals and antioxidant capacities in vitro of P. decorate leaves were investigated. Materials and methods: Ethanol, petroleum ether, acetidin, n-butyl alcohol and aqueous extracts of Pyrola decorate leaves were prepared by solvent sequential process, and then isolated and purified to obtain phytochemicals. Cell viability was measured by MTT assay. PC12 cells were pretreated for 24h with different extractions of P. decorate leaves at concentrations of 0.1, 0.5, 1, 5 and 10mg/mL, then H2O2 of 0.4mM was added in all samples for an additional 2h. The antioxidant capacities of betulin, ursolic acid and monotropein were determined in PC12 cells against H2O2 induced cytotoxicity in vitro as well. Results: Nine compounds (1-9) were isolated and structurally determined by spectroscopic methods, especially 2D NMR analyses. Ethanol extract treated groups showed inhibitory activity with IC50 value of 10.83mg/mL. Betulin, ursolic acid and monotropein were isolated from P. decorate, and demonstrated with IC50 values of 6.88, 6.15 and 6.13g/mL, respectively. Discussion and conclusions: In conclusion, Pyrola decorate is a potential antioxidative natural plant and worth testing for further pharmacological investigation in the treatment of oxidative stress related neurological disease
Isolation, structure elucidation and biosynthesis of benzo[b]fluorene nenestatin A from deep-sea derived Micromonospora echinospora SCSIO 04089
No full textBenzofluorene-containing angucyclines, such as lomaiviticins, kinamycins, and fluostatins, have attracted increasing attentions on chemical synthesis and biosynthesis due to their unique structures and potent biological activities. Our continuous searching for novel natural products from deep-sea derived actinomycetes led to the discovery of nenestatin A (1), a benzo[b]fluorene compound possessing a carbon scaffold similar to the monomeric lomaiviticins, from the deep sea-derived Micromonospora echinospora SCSIO 04089. In addition, the biosynthetic gene cluster of nenestatin A (nes) was identified by a genome sequencing approach and comparative bioinformatics analysis with the lomaiviticin biosynthetic gene clusters. The nes-gene cluster was further verified by in vivo gene disruption experiments to afford a biosynthetic intermediate homo-dehydrorabelomycin E (2). This study adds a new member to the growing family of benzofluorene angucyclines and paves the way for further biosynthetic investigations. (C) 2017 Elsevier Ltd. All rights reserved
Application of a generalized additive model (GAM) for estimating chlorophyll-a concentration from MODIS data in the Bohai and Yellow Seas, China
No full textIn optically complex waters, it is important to evaluate the accuracy of the standard satellite chlorophyll-a (chl-a) concentration algorithms, and to develop accurate algorithms for monitoring the dynamics of chl-a concentration. In this study, the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite remote-sensing reflectance and concurrent in situ measured chl-a (20102013) were used to evaluate the standard OC3M algorithm (ocean chlorophyll-a three-band algorithm for MODIS) and Graver-Siegel-Maritorena model version 1 (GSM01) algorithm for estimating chl-a concentration in the Bohai and Yellow Seas (BYS). The results showed that the chl-a algorithms of OC3M and GSM01 with global default parameters presented poor performance in the BYS (the mean absolute percentage difference (MAPD) and coefficient of determination (R-2) of OC3M are 222.27% and 0.25, respectively; the MAPD and R-2 of GSM01 are 118.08% and 0.07, respectively). A novel statistical algorithm based on the generalized additive model (GAM) was developed, with the aim of improving the satellite-derived chl-a accuracy. The GAM algorithm was established using the in situ measured chl-a concentration as the output variable, and the MODIS above water remote-sensing reflectance (visible bands at 412, 443, 469, 488, 531, 547, 555, 645, 667, and 678 nm) and bathymetry (water depth) as input variables. The MAPD and R-2 calculated between the GAM and the in situ chl-a concentration are 39.96% and 0.67, respectively. The results suggest that the GAM algorithm can yield a superior performance in deriving chl-a concentrations relative to the standard OC3M and GSM01 algorithms in the BYS
Atmospheric Correction of Landsat-8/OLI Imagery in Turbid Estuarine Waters: A Case Study for the Pearl River Estuary
No full textSeveral methods have been proposed for atmospheric correction over turbid waters, including near-infrared (NIR) band based or short-wave infrared (SWIR) band-based where the signal in turbid waters can be assumed zero. Here, we adopt a new infrared extrapolation method to extend the existing turbid water atmospheric correction of the operational land imager (OLI) data on Landsat-8 platform. The atmospheric correction uses the extrapolated Rayleigh-corrected reflectance at NIR and SWIR bands to derive the ratios of NIR to SWIR and visible aerosol single-scattering contributions (aerosol epsilon). Taking the Pearl River Estuary as an example, the magnitude and spatial distribution of reflectance from OLI compare well with those of concurrent moderate resolution imaging spectroradiometer /Aqua based on SWIREatmospheric correction method. The linear regression coefficients between the resampled OLI and Aqua data have demonstrated the proposed atmospheric correction method can provide robust and realistic reflectance. The advantages of the high spatial resolution made the OLI data a good source for applications in coastal and estuarine waters
Observing subsurface changes of two anticyclonic eddies passing over the Izu-Ogasawara Ridge
No full textEddy-bathymetry interactions are common in the ocean, but the full evolution of the interaction is difficult to observe below the surface. Using 17 Iridium Argo floats, we continually track two anticyclonic eddies (AEs) in the North Pacific that migrate westward and encounter the Izu-Ogasawara Ridge. Based on over 5000 Argo profiles following the two AEs, this study presents the first detailed descriptions of changes in eddy vertical structure and diapycnal mixing as the two AEs pass the Ridge. There, we find that isopycnals dome up and the eddy diameter increases, while the diapycnal mixing is enhanced-to the order of 10(-4) m(2) s(-1) or larger, in comparison with an ambient of 10(-5) m(2) s(-1). The enhanced mixing around the AE center in the upper -1000m appears where the underlying bathymetry is shallower than -4000m and is mainly sustained by tidally generated internal waves