Purification,Chemical Characterization,and Bioactivity of an Extracellular Polysaccharide Produced by the Marine Sponge Endogenous Fungus <Emphasis Type="Italic">Alternaria</Emphasis> sp. SP-32

Marine sponges are ancient and simple multicellular filter-feeding invertebrates attached to solid substrates in benthic habitats and host a variety of fungi both inside and on their surface because of its unique ingestion and digest system. Investigation on marine sponge-associated fungi mainly focused on the small molecular metabolites, yet little attention had been paid to the extracellular polysaccharides. In this study, a homogeneous extracellular polysaccharide AS2-1 was obtained from the fermented broth of the marine sponge endogenous fungus Alternaria sp. SP-32 using ethanol precipitation, anion-exchange, and size-exclusion chromatography. Results of chemical and spectroscopic analyses showed that AS2-1 was composed of mannose, glucose, and galactose with a molar ratio of 1.00:0.67:0.35, and its molecular weight was 27.4 kDa. AS2-1 consists of a mannan core and a galactoglucan chain. The mannan core is composed of (1→6)-α-Manp substituted at C-2 by (1→2)-α-Manp with different degrees of polymerization. The galactoglucan chain consists of (1→6)-α-Glcp residues with (1→6)-β-Galf residues attached to the last glucopyranose residue at C-6. (1→6)-β-Galf residues have additional branches at C-2 consisting of disaccharide units of (1→2)-β-Galf and (1→2)-α-Glcp residues. The glucopyranose residue of the galactoglucan chain is linked to the mannan core. AS2-1 possessed a high antioxidant activity as evaluated by scavenging of 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radicals in vitro. AS2-1 was also evaluated for cytotoxic activity on Hela, HL-60, and K562 cell lines by the MTT and SRB methods. The investigation demonstrated that AS2-1 was a novel extracellular polysaccharide with different characterization from extracellular polysaccharides produced by other marine microorganisms.     

Prevalence and phylogenetic characterization of canine coronavirus from diseased pet dogs in Beijing,China

正Dear Editor,Canine coronavirus including canine coronavirus(CCoV)and canine respiratory coronavirus(CRCoV)have been recognized as pathogenic viruses to dogs worldwide,causing enteric and respiratory issues(Buonavoglia et al.,2006).Zoonotic transfer of the viruses from the animal kingdom to humans has been repeatedly observed over the past decade,     

Sensitive and selective turn‐on fluorescence method for cetyltrimethylammonium bromide determination based on acridine orange–polystyrene sulfonate complex

This work proposed a rapid and novel fluorescence‐sensing system using a complex of acridine orange (AO) and polystyrene sulfonate (PSS) to sensitively recognize and monitor cetyltrimethylammonium bromide (CTAB) in an aqueous medium. AO can interact with PSS and a complex is formed via electrostatic attraction and hydrophobic interaction. The fluorescence of AO is greatly quenched after the introduction of PSS. Upon its subsequent addition, CTAB can interact and form a complex with PSS because the electrostatic attraction between CTAB and PSS is much stronger than that between AO and PSS, which results in significant fluorescence recovery. Interestingly, the proposed method can be applied for the discrimination and detection of surfactants with different hydrocarbon chain lengths due to their different binding affinity toward PSS. The detection limit for CTAB is as low as 0.2 µg/mL and the linear range is from 0.5 to 3.5 µg/mL. Moreover, we applied the sensor to the successful detection of CTAB in water samples. Copyright © 2015 John Wiley & Sons, Ltd.     

miRNA‐532‐5p functions as an oncogenic microRNA in human gastric cancer by directly targeting RUNX3

Accumulating data reveal that microRNAs are involved in gastric carcinogenesis. To date, no information was reported about the function and regulatory mechanism of miR‐532‐5p in human gastric cancer (GC). Thus, our study aims to determine the role and regulation of miR‐532‐5p in GC. Here, we found that transient and stable overexpression of miR‐532‐5p dramatically increased the potential of colony formation and migration of GC cells, decreased the percentage of cells in G1 phase and cell apoptosis in vitro, and increased the weight of mice lungs and number of lung xenografts in vivo. Gain‐of‐function, loss‐of‐function and luciferase activity assays demonstrated that miR‐532‐5p negatively regulated the expression of RUNX3 and its targets directly. We also found that miR‐532‐5p level was negatively correlated with RUNX3 gene expression in various GC cell lines. Our results indicate that miR‐532‐5p functions as an oncogenic miRNA by promoting cell growth, migration and invasion in human GC cells.