Pharmacokinetic studies and anticancer activity of curcumin-loaded nanostructured lipid carriers

In order to investigate the potential of nanostructured lipid carriers for efficient and targeted delivery of curcumin, the pharmacokinetic parameters of curcumin-loaded nanostructured lipid carriers (Cur-NLC) were evaluated in rats after a single intraperitoneal dose of Cur-NLC. In addition, the anticancer activity of Cur-NLC against human lung adenocarcinoma A549 cells was verified by a cellular uptake study, and a cytotoxicity and apoptosis assay. Bioavailability of Cur-NLC was better than that of native curcumin (p > 0.01), as seen from the area under the plasma concentration-time curve (AUC), maximum plasma concentration (Cmax), mean residence time (MRT) and total plasma clearance (CLz/F). Cur-NLC has a more obvious lung-targeting property in comparison with native curcumin. Cur-NLC showed higher anticancer activity in vitro against A549 cells than native curcumin (IC50 value of 5.66 vs. 9.81 mg L–1, respectively). Meanwhile, Cur-NLC treated A549 cells showed a higher apoptosis rate compared to that of native curcumin. These results indicate that NLC is a promising system for the delivery of curcumin in the treatment of lung adenocarcinoma

Curcumin-loaded nanostructured lipid carrier induced apoptosis in human HepG2 cells through activation of DR5/caspases-mediated extrinsic apoptosis pathway

Curcumin is a lipophilic anti-cancer compound extracted from turmeric. Our previous study demonstrated that the curcumin-loaded nanostructured lipid carrier (Cur-NLC) exhibits superior anti-cancer activity in inhibiting proliferation as well as inducing apoptosis of human HepG2 cells compared to native curcumin. This study aims to unveil the mechanisms underlying the pro-apoptotic effect of Cur-NLC on HepG2 cells. Evidence indicates that low expression of death receptors (DRs) on cancer cell membranes leads to attenuated apoptosis signaling. This study showed that Cur-NLC significantly increased total expression of DR5 protein while simultaneously upregulated cell membrane expression of DR5. Cur-NLC significantly increased caspase-8 and caspase-3 activities, accompanied by increased apoptosis. Furthermore, enhanced apoptosis was inhibited in the presence of a pan-caspase inhibitor, Z-VAD-FMK. Therefore, Cur-NLC induced activation of the extrinsic apoptosis pathway via modulating the DR5/caspase-8/-3 mediated apoptosis pathway in HepG2 cells, suggesting that Cur-NLC is a promising therapeutic agent or supplement for the treatment of hepatocellular carcinoma

Exploring the plankton bacteria diversity and distribution patterns in the surface water of northwest pacific ocean by metagenomic methods

The study of marine microbial communities is crucial for comprehending the distribution patterns, adaptations to the environment, and the functioning of marine microorganisms. Despite being one of the largest biomes on Earth, the bacterioplankton communities in the Northwest Pacific Ocean (NWPO) remain understudied. In this research, we aimed to investigate the structure of the surface bacterioplankton communities in different water masses of the NWPO. We utilized metagenomic sequencing techniques and cited previous 16S rRNA data to explore the distribution patterns of bacterioplankton in different seasons. Our results revealed that Cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria dominated the microbial communities, accounting for over 95% of the total. During spring, we observed significant differentiation in community structure between the different water masses. For instance, Prochlorococcus and Pseudoalteromonas were primarily distributed in the nutrient-deficient subtropical countercurrent zone, while Flavobacteriaceae and Rhodobacteraceae were found in the Kuroshio-Oyashio mixing zone. During summer, the surface planktonic bacteria communities became homogenized across regions, with Cyanobacteria becoming the dominant group (68.6% to 84.9% relative abundance). The metabolic processes of the microorganisms were dominated by carbohydrate metabolism, followed by amino acid transport and metabolism. However, there was a low relative abundance of functional genes involved in carbohydrate metabolism in the Kuroshio-Oyashio mixing zone. The metagenomic data had assembled 37 metagenomic-assembled genomes (MAGs), which belong to Proteobacteria, Bacteroidetes, and Euryarchaeota. In conclusion, our findings highlight the diversity of the surface bacterioplankton community composition in the NWPO, and its distinct geographic distribution characteristics and seasonal variations

Reviews and Syntheses: Ocean acidification and its potential impacts on marine ecosystems

Ocean acidification, a complex phenomenon that lowers seawater pH, is the net outcome of several contributions. They include the dissolution of increasing atmospheric CO2 that adds up with dissolved inorganic carbon (dissolved CO2, H2CO3, HCO3−, and CO32−) generated upon mineralization of primary producers (PP) and dissolved organic matter (DOM). The aquatic processes leading to inorganic carbon are substantially affected by increased DOM and nutrients via terrestrial runoff, acidic rainfall, increased PP and algal blooms, nitrification, denitrification, sulfate reduction, global warming (GW), and by atmospheric CO2 itself through enhanced photosynthesis. They are consecutively associated with enhanced ocean acidification, hypoxia in acidified deeper seawater, pathogens, algal toxins, oxidative stress by reactive oxygen species, and thermal stress caused by longer stratification periods as an effect of GW. We discuss the mechanistic insights into the aforementioned processes and pH changes, with particular focus on processes taking place with different timescales (including the diurnal one) in surface and subsurface seawater. This review also discusses these collective influences to assess their potential detrimental effects to marine organisms, and of ecosystem processes and services. Our review of the effects operating in synergy with ocean acidification will provide a broad insight into the potential impact of acidification itself on biological processes. The foreseen danger to marine organisms by acidification is in fact expected to be amplified by several concurrent and interacting phenomena

Satellite-derived surface water pCO(2) and air-sea CO2 fluxes in the northern South China Sea in summer

An empirical approach is presented for the estimation of the partial pressure of carbon dioxide (pCO(2)) and air-sea CO2 fluxes in the northern South China Sea in summer using satellite-derived sea surface temperatures (SSTs), chlorophyll-a (Chl a) concentrations, and wind fields. Two algorithms were tested. The first used an SST-dependent equation, and the other involved the introduction of Chl a. Regression equations were developed for summer based on in situ data obtained in July, 2004. Using the monthly average SST and Chl a fields derived from the advanced very high resolution radiometer (AVHRR) and the SeaWiFS (sea-viewing wide field of view sensor), respectively, the monthly pCO(2) fields were computed. The derived pCO(2) was compared with the shipboard pCO(2) observations conducted in July, 2000. This resulted in a root-mean-square error of 4.6 mu atm, suggesting that the satellite-derived pCO(2) was in general agreement with the in situ observations. The air-sea CO2 flux was further computed with the aid of the monthly mean QuikSCAT wind speed. We contend that more shipboard data are necessary for refining the empirical algorithms and reducing the uncertainty in the results. (C) 2009 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.National Basic Research Program of China [2009CB421200, 2009CB421201]; National Natural Science Foundation of China [40521003, 90711005]; High-Tech R&D Program of China [2006AA09A302, 2007AA09Z127

On the seasonal variation of air-sea CO2 fluxes in the outer Changjiang (Yangtze River) Estuary, East China Sea

Based upon seven field surveys conducted during April 2005 - April 2008, we examined the surface partial pressure of CO2 (pCO(2)) and dissolved oxygen (DO) in the outer Changjiang (Yangtze River) Estuary, on the inner shelf of the East China Sea (ECS). This area represents a most dynamic zone of the ECS where high pCO(2) riverine water meets with highly productive shelf waters, covering a 2 degrees x 3 degrees area, similar to 10% of the surface area of the entire ECS. Surface pCO(2) ranged 320 - 380 mu atm (average similar to 345 mu atm) in winter, 180 - 450 mu atm (average similar to 330 mu atm) in spring, 150 - 620 mu atm (average similar to 310 mu atm) in summer and 120 - 540 mu atm (average similar to 375 mu atm) in autumn. The seasonal variation pattern of surface DO generally mirrored that of pCO(2), ranging 95% - 105% in winter, 96% - 142% (average 110%) in spring, 73% - 192% (average 718%) in summer and 81% - 178% (average 102%) in autumn. The dynamics of pCO(2) drawdown and DO enhancement in the warm seasons (from April to October) appeared to be controlled by primary productivity and air - sea exchange, while mixing dominated the aqueous pCO(2) in the cold seasons (from November to March of the following year). This study showed that the outer Changjiang Estuary served as a moderate or significant sink of atmospheric CO2 in winter, spring and summer, while it turned to a net source in autumn. The integrated sea - air CO2 flux in the outer Changjiang Estuary was estimated as -1.9 +/- 1.3 mol m(-2) year(-1), which is double the recent sea-air CO2 flux estimation for the northern ECS. (C) 2009 Elsevier B.V. All rights reserved

Distribution, fluxes and decadal changes of nutrients in the Jiulong River Estuary, Southwest Taiwan Strait

The Jiulong River Estuary (JRE) is a typical subtropical macro-tide estuary on the southwest coast of the Taiwan Strait (TWS), which has been greatly impacted by human activities over the past 30 years. To understand nutrient dynamics and fluxes under such a heavy background of anthropogenic perturbation, eight cruises were conducted from April 2008 to April 2011, covering both wet (May to September) and dry (October to April next year) seasons. Nutrient concentrations were very high for the freshwater end-member in the upper reach of the JRE (nitrate (NO3-N): 120-230 mu mol L-1; nitrite (NO2-N): 5-15 mu mol L-1; ammonium (NH4-N): 15-170 mu mol L-1; soluble reactive phosphorus (SRP): 1.2-3.5 mu mol L-1; dissolved silicate (DSi): 200-340 mu mol L-1). In dry seasons, concentrations of these nutrients were higher than in wet seasons. Nitrate was the dominant chemical species of dissolved inorganic nitrogen (DIN), with percentages of 67%-96% in wet seasons and 55%-72% in dry seasons. Distributions of NO3-N and DSi against salinity were nearly constant during all cruises, and showed generally conservative mixing behaviors in the estuary (1 < Salinity < 32). The concentrations of SRP varied within a narrow range of 1.0-2.0 mu mol L-1 in low/middle salinity areas, and they were quickly diluted by relatively oligotrophic near-shore seawater in the high salinity region. Based on a temporally high-resolution water discharge dataset, riverine fluxes of DIN, SRP and DSi into the JRE were calculated at 34.3x10(3) t N a(-1), 0.63x10(3) t P a(-1) and 72.7x10(3) t Si a(-1), respectively. In comparison, estuarine export fluxes of DIN, SRP and DSi from the JRE to the TWS were estimated at 34.8x10(3) t N a(-1), 0.82x10(3) t P a(-1) and 71.6x10(3) t Si a(-1). The estuarine addition flux of SRP was independently estimated at 0.16x10(3) t P a(-1). In comparison with major world rivers, the Jiulong River shows a very high areal yield rate of NO3-N. In comparison with historical datasets from 1980s-1990s, concentrations of NO3-N and SRP increased 2-3 times in upper/middle areas of the JRE, while DSi remained at the same level. The latter is much different from decadal nutrient changes in the Mississippi River and the Yangtze River/Estuary. Such nutrient changes may fundamentally contribute to recent red tide events in the JRE and adjacent Xiamen Bay.National Natural Science Foundation of China (NSFC) [40810069004]; National Basic Research Program of China [2009CB421204]; State Oceanic Administration of China [DOMEP-MEA-01-10

Short-term dynamics of nutrients influenced by upwelling in a small oligotrophic coastal ecosystem, Gan Bay, in the northwest Philippines

We present a time-series analysis of nutrient and pCO(2) (partial pressure of CO2) levels in an oligotrophic coastal ecosystem (Gan Bay), which was likely to be influenced by upwelled subsurface water. Gan Bay is off Currimao Harbor, in the northwest Philippines and is located at the boundary of the South China Sea (SCS). This 42-h time-series observation was conducted in December 2006. In addition to continuous observations of dissolved oxygen (DO) and pCO(2), discrete samples were collected at a depth of 5 m every 3 h for measurements of nutrients, including soluble reactive phosphorus (SRP) and inorganic nitrogen (NO3- + NO2-) in order to examine their dynamics and possible physical and biological controls. We observed remarkably large short-term variations in the surface water, spanning a 10-fold change for SRP (32-330 nM) and from <0.3 mu M to 4.3 mu M for (NO3- + NO2-. DO also varied substantially from a lower end of 171 to 205 mu M O-2. Surface water pCO(2) changed from an equilibrium stage with the atmosphere (similar to 386 mu atm) to a stage where it was a significant source for the atmospheric CO2 (seawater pCO(2) similar to 469 mu atm). We found that the variation of nutrients was driven neither by tidal mixing nor by biological activities, as was suggested by the variations in the total bacterial abundance and chlorophyll a. Instead, our inverse T-S relationship suggested a two end-member mixing process during the observation period. The N:P ratio throughout the observation period was similar to 13.2, which is characteristic of SCS subsurface and deep waters. Moreover, pCO(2) was correlated inversely with the sea surface temperature. It is likely, therefore, that an upwelled subsurface cold water with high nutrients, low-temperature and high-pCO(2) existed. It should be noted that this upwelled cold water did not appear to impact the entire observation period (approximately 35 h of 42 h), which might suggest an extremely dynamic nature for this upwelled cold water mass. (C) 2009 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved

Reviews and Syntheses: Ocean acidification and its potential impacts on marine ecosystems

Ocean acidification, a complex phenomenon that lowers seawater pH, is the net outcome of several contributions. They include the dissolution of increasing atmospheric CO₂ that adds up with dissolved inorganic carbon (dissolved CO₂, H₂CO₃, HCO₃⁻, and CO₃²⁻) generated upon mineralization of primary producers (PP) and dissolved organic matter (DOM). The aquatic processes leading to inorganic carbon are substantially affected by increased DOM and nutrients via terrestrial runoff, acidic rainfall, increased PP and algal blooms, nitrification, denitrification, sulfate reduction, global warming (GW), and by atmospheric CO₂ itself through enhanced photosynthesis. They are consecutively associated with enhanced ocean acidification, hypoxia in acidified deeper seawater, pathogens, algal toxins, oxidative stress by reactive oxygen species, and thermal stress caused by longer stratification periods as an effect of GW. We discuss the mechanistic insights into the aforementioned processes and pH changes, with particular focus on processes taking place with different timescales (including the diurnal one) in surface and subsurface seawater. This review also discusses these collective influences to assess their potential detrimental effects to marine organisms, and of ecosystem processes and services. Our review of the effects operating in synergy with ocean acidification will provide a broad insight into the potential impact of acidification itself on biological processes. The foreseen danger to marine organisms by acidification is in fact expected to be amplified by several concurrent and interacting phenomena