Pollen distribution and transportation patterns in surface sediments of Liaodong Bay, China.

Understanding pollen transport pathways and dispersal mechanism from the land to sea is a prerequisite for marine palynological study. Palynological analysis of 164 surface sediment samples in Liaodong Bay, and 39 analogous surface alluvium samples from its five inflowing rivers, identifies the distribution patterns, pathways and possible sources of pollen and spores. The results show that pollen and spore assemblages in surface sediments are well correlated to regional vegetation distribution, and the variations of pollen assemblage in different parts of Liaodong Bay reflected local vegetation changes along the coast. High pollen concentrations are mainly distributed in the estuaries of inflowing rivers, coastal waters and sea muddy areas. The pollen assemblage characteristics of alluvial samples are similar to those from coastal waters with water depths <8.5 m. Samples from the alluvium and surface sediments of coastal waters were dominated by herbaceous pollen taxa including Artemisia, Amaranthaceae, Poaceae, Cyperaceae and Typha. Herbaceous pollen percentages and concentrations decreased as the water depth increased, indicating that pollen and spores in the coastal waters of Liaodong Bay are mainly carried by the inflowing rivers. However, pollen assemblages for samples with water depth >8.5 m are significantly different from those of the alluvium. In samples taken below a depth of 8.5 m, the arboreal pollen is dominated by airborne Pinus, and there is a high number of the waterborne Selaginella fern spores, both of which are sourced from a wider region. In the Liaodong Bay, both wind and ocean current transportation determines the pollen distribution patterns in deeper waters, while fluvial and longshore current transportation determines the pollen assemblages found in shallow waters. The dispersal characteristics of pollen assemblages between the land and the sea in Liaodong Bay provide a theoretical basis for the interpretation of fossil pollen assemblages and past sea level changes.

Extraction, purification, and determination of the gastroprotective activity of glucomannan from Bletilla striata.

In this study, a water-soluble polysaccharide (BSP) was extracted and purified from pseudobulb of Bletilla striata. The preliminary structure and gastroprotective activity of BSP were analyzed. Results indicate that BSP is a glucomannan with a molar ratio of 7.45:2.55 (Man:Glc), and its molecular weight is approximately 1.7 × 105 Da. BSP displayed outstanding protective action against ethanol-induced GES-1 cell injury in vitro, as well as, excellent gastroprotective activity in vivo. Especially, a high-dose of BSP (100 mg/kg) could reduce the ulcer index of the gastric mucosa and increase the percentage of ulcer inhibition, which possibly caused by enhancing the antioxidant capacity and inhibiting the apoptotic pathway in gastric tissue. Interestingly, BSP exhibited a comparative gastroprotective activity to that of positive control (omeprazole). In summary, our results indicated that BSP could be considered as a potential supplement for the prevention of gastric injury.

Curcumin inhibiting Th17 cell differentiation by regulating the metabotropic glutamate receptor-4 expression on dendritic cells.

Th17 cells have been categorized as a new lineage of CD4+ T cells, and played a crucial role in the pathogenesis of numerous autoimmune disorders. Type 4 metabotropic glutamate receptor (mGluR4), a member of group III mGluRs, recently has been found to be expressed in many types of immune cells and mediate adaptive immunity. Curcumin has been shown to exhibit potent anti-inflammatory, antimutagenic and anticarcinogenic properties. For the past few years, it has gradually been regarded as an pluripotent immunomodulatory agent that can regulate the activation of immune cells. In the present study, we investigated the efficacy and mechanism of curcumin on Th17 cells. Treatment with curcumin significantly reduced IL-6 and IL-23 production by dendritic cells (DC). Additionally, it had a dramatic reduction in the proliferation of CD4+ T cells co-cultured with DC. Furthermore, expression of the Th17 cells related cytokine profiles (IL-17A and RORγt) was dramatically decreased in curcumin-treated groups. These findings indicated that curcumin inhibited the differentiation and development of Th17 cells. Besides, we found that mGluR4 was constitutively expressed in mouse bone marrow derived DC (BMDC) for the first time. In addition, mGluR4 siRNA-transfected BMDC tipped the balance of T cell differentiation in favor of the Th17 phenotype. We first reported that curcumin increased the mGluR4 expression in mouse BMDC activated with LPS, which likely contributed to the mechanism of inhibiting the Th17 cell differentiation. Our findings suggest that curcumin might be a potential candidate for Th17 related autoimmune disorders.

Distribution, sources and potential toxicological significance of polycyclic aromatic hydrocarbons (PAHs) in surface soils of the Yellow River Delta, China.

PAH concentrations of 61 surface soil samples collected from the Yellow River Delta (YRD), China were measured to determine occurrence levels, sources, and potential toxicological significance of PAHs. The total concentrations of ∑PAHs ranged from 27 to 753 ng/g d.w., with a mean of 118±132 ng/g. The highest concentrations was found in the mid-southern part of the YRD (753 ng/g), which was associated with the oil exploration. The ratios indicated that the PAHs throughout the YRD were mostly of pyrogenic origin; while various sites in mid-southern part in the region were derived mainly from the petrogenic sources. Multivariate statistical analyses supported that the PAHs in surface soils of the YRD were principally from the coal and biomass combustion, petroleum spills, and/or vehicular emissions. The toxic assessment suggested that the PAHs in soils were at low potential of ecotoxicological contamination level for the YRD.