[Effect of Water Components on Aggregation and Sedimentation of Polystyrene Nanoplastics].

The aggregation and sedimentation of micro/nano-plastics significantly affect their migration and distribution in the environment. This study investigated the effects of Na+ and natural organic matter （NOM） on the aggregation and sedimentation of polystyrene nano-plastics （PS-NPs） in the aqueous phase. Six types of water， such as seawater， lake water， and domestic sewage， were used to evaluate the above effects and other potential influencing factors. The results indicated that Na+ could facilitate the sedimentation of PS-NPs when it was less than 80 mmol·L-1， whereas it could promote the aggregation and suspension of PS-NPs when the concentration was greater than 80 mmol·L-1. NOM molecules affected the aggregation and sedimentation of PS-NPs by changing the ζ potential and relative density of particles via forming a multilayer adsorption structure with Na+ on the particle surface. It was observed that NOM greater than 10 mg·L-1 enhanced the dispersion and suspension of PS-NPs， which might have been attributed to the decrease in relative density of the particles as a large amount of NOM was absorbed onto the surface. Compared with synthetic waters， environmental waters enhanced the aggregation of PS-NPs， which may have been related to the amino acid， protein， and other organic macro-molecules in the water.

Alleviation of palmitic acid-induced endoplasmic reticulum stress by augmenter of liver regeneration through IP3R-controlled Ca2+ release.

The aberrant release of Ca2+ from the endoplasmic reticulum (ER) contributes to the onset of ER stress, which is closely related to the pathogenesis of non-alcoholic fatty liver disease. We previously reported that augmenter of liver regeneration (ALR) alleviates ER stress and protects hepatocytes from lipotoxicity. However, the link between ALR protection and the suppression of ER stress remains unclear. In this study, we investigated whether the protection against liver steatosis afforded by ALR is related to its inhibition of calcium overflow from the ER to the mitochondria. The treatment of HepG2 cells with palmitic acid (PA) upregulated IP3R expression, triggering ER-luminal Ca2+ release and inducing ER stress. However, in ALR-transfected (ALR-Tx) HepG2 cells, PA-induced cell injury was clearly alleviated compared with that in vector-Tx cells. After exposure to PA, IP3R expression was downregulated and ER stress was effectively inhibited in the ALR-Tx cells, and ER-Ca2+ release and simultaneous mitochondrial Ca2+ uptake were lower than those in vector-Tx cells. The knockdown of ALR expression with shRNA abolished the protective effects afforded by ALR transfection. PA treatment also suppressed the interaction between BCL-2 and IP3R in HepG2 cells, whereas this interaction was massively enhanced in the ALR-Tx cells, effectively reducing the IP3R-mediated ER-Ca2+ release and thus mitochondrial Ca2+ influx. Our results suggest that the inhibition of ER stress by ALR is related to the interruption of the interaction between BCL2 and IP3R, demonstrating a novel mechanism of ER stress resistance in ALR-Tx cells.

Molecular characterization of a novel gene from Synechocystis sp. PCC 6803.

A novel gene slr2049 was identified in Synechococcus sp. PCC7002 by homologous alignment. The features and possible functions of slr2049 gene were predicted by bioinformatics analysis. The function of slr2049 was analyzed in vitro with a heterologous Escherichia coli system with plasmids conferring biosynthesis of phycocyanobilin (PCB) and of the acceptor proteins, ß-phycocyanin (CpcB). The resulting products were evaluated with SDS-PAGE and absorption spectra. The function of slr2049 was further analyzed via site-directed mutations. Two mutants, slr2049 (W14L) and slr2049 (Y132S) were generated. The results showed that Slr2049 could catalyze the chromophorylation of CpcB. Compared to wild type, mutant Slr2049 (W14L) had red-shifted absorbance maxima and was not highly fluorescent as the wild-type. However, mutant Slr2049 (Y132S) was almost the same as the wild-type. In conclusion, our study suggests that we have cloned a novel gene and this gene may play an important role in attachment of the chromophores to the apo-proteins.

[GC-MS analysis on the chemical constituents of essential oil from bark of Horsfieldia hainanensis].

OBJECTIVE: To analyze the constituents of the essential oil from the bark of Horsfieldia hainanensis. METHODS: The volatile oil was obtained by steam distillation. The chemical constituents were separated and identified by gas chromatography-mass spectrometry (GC-MS). The relative contents were determined by area normalization. RESULTS: The extraction rate of the bark of Horsfieldia hainanensis was 0.14%. 32 compounds were separated and identified, which accounted for 98.62% of the essential oil. The main chemical components of the essential oil were Copaene (25.55%), Naphthalene, 1,2,3,5,6,8a-hexahydro-4,7-dimethyl-1-(1-methylethyl)-(11.14%), Hexanedioic acid, bis(2-ethylhexyl) ester (8.09%) , 9-Octadecenoic acid (7.04%), etc. CONCLUSION: It has provided scientific foundation for exploitation and utilization of Horsfieldia hainanensis.

[Supercritical CO2 fluid extraction of Rosmarinus officinalis and capability of extracts eliminate OH radical].

OBJECTIVE: Supercritical CO2 fluid extraction process of antioxidation active components from Rosmarinus officinalis was studied. METHOD: A new extraction process of components extracted from R. officinalis by supercritical CO2 fluid extraction (SFE-CO2 ) was studied in detail. The capability of that the extract eliminate *OH radical was tested by electron paramagnetic resonance (EPR) technique and spin catch technique. RESULT AND CONCLUSION: With free radical clearance as index, by range and variance analysis, the optimum extraction process conditions were: keeping pressure at 30 MPa and temperature at 75 degrees C for 1 h, in the same time adding alcohol 0.30 mL x g(-1).

[Transformer genes and sex determination of C. elegans and D.melanogaster].

Sex determination of Drosophila melanogaster and Caeborhabditis elegans has been known in detail. Great progress, is achieved in recent years, is the research of transformer genes, which are those of most important genes in sex determination in both species. In this paper, molecular character, genetic function and the relative genes of transformer genes are particularly described. On the basis,a primary comparison and analysis between the molecular mechanism of sex determination in C.elegans and D. melanogaster are presented.