Multivariate analysis of elements in Chinese brake fern as determined using neutron activation analysis.

Pytoremediaton of arsenic (As) contamination using Chinese brake fern (Pteris vittata L.), an As hyperaccumulator has proven potential because of its cost-effectiveness and environmental harmonies. Aiming to investigate the elemental correlation in Chinese brake fern, 20 elements (As, Br, Ca, Ce, Co, Cr, Eu, Fe, Hf, La, Na, Nd, K, Rb, Se, Sm, Sr, Th, Yb and Zn) were measured in the fronds and roots of the fern by neutron activation analysis. The ferns were sampled from two sites with high geogenic As levels: Zimudang (ZMD) and Lanmuchang (LMC) in Guizhou Province, China. Multivariate statistic analysis was performed to explore the interrelationship between these elements, especially between As and other elements. As was found to be positively related to K, Na, La, and Sm in both the roots and the fronds, suggesting that these four elements might operate as synergies to As during uptake and transportation processes. Se was positively related to most of the other cations measured, except in the fronds of the fern at ZMD, where Br replaced Se as positively related to the other cations. The difference of As and Se in correlation with other cationic elements suggested that the two anionic elements play different roles in elemental uptake processes. Our findings of elemental correlation highlight the importance of the anion- cation balance in Chinese brake fern.

In vitro fermentation behaviors of fucosylated chondroitin sulfate from Pearsonothuria graeffei by human gut microflora.

A fucosylated chondroitin sulfate (FCS-pg) with highly repeated structure from Pearsonothuria graeffei was subjected to a in vitro fermentation model to investigate its fermentability and effects on human gut microflora. High performance liquid chromatography (HPLC) measurement found FCS-pg can be fermented to short chain fatty acids (SCFAs) by gut microflora from partial human fecal samples. 16S rRNA gene-based polymerase chain reaction-based denaturing gradient gel electrophoresis (PCR-DGGE) profiling and real-time quantitative PCR analysis showed that FCS-pg mainly increased the proportions of Clostridium cluster XI, Bacteriodes prevotella group, Bifidobacterium genus, Clostridium cluster I and Clostridium cluster XIVab, whereas the numbers of the Enterobacteriaceae and Lactobacillus decreased. These results indicated that FCS-pg was mainly fermented by Bacteroides, Bifidobacterium and Clostridium. It increased the content of probiotics bacteria in achieving health-enhancing effect, was slightly different than most sulfated polysaccharides from marine animals. The current study provides useful new information on the mechanism of absorption and functional activity on FCS-pg within the gastrointestinal tract of the human body.

Arsenic accumulation by two brake ferns growing on an arsenic mine and their potential in phytoremediation.

In an area near an arsenic mine in Hunan Province of south China, soils were often found with elevated arsenic levels. A field survey was conducted to determine arsenic accumulation in 8 Cretan brake ferns (Pteris cretica) and 16 Chinese brake ferns (Pteris vittata) growing on these soils. Three factors were evaluated: arsenic concentration in above ground parts (fronds), arsenic bioaccumulation factor (BF; ratio of arsenic in fronds to soil) and arsenic translocation factor (TF; ratio of arsenic in fronds to roots). Arsenic concentrations in the fronds of Chinese brake fern were 3-704 mg kg-1, the BFs were 0.06-7.43 and the TFs were 0.17-3.98, while those in Cretan brake fern were 149-694 mg kg-1, 1.34-6.62 and 1.00-2.61, respectively. Our survey showed that both ferns were capable of arsenic accumulation under field conditions. With most of the arsenic being accumulated in the fronds, these ferns have potential for use in phytoremediation of arsenic contaminated soils.

Structure and chain conformation of a neutral intracellular heteropolysaccharide from mycelium of Paecilomyces cicadae.

A neutral heteropolysaccharide (PCIPS2) was isolated and purified from mycelium of Paecilomyces cicadae, which was investigated to be mainly composed of D-mannose, L-rhamnose, 3-O-methyl-D-galactose, D-glucose and D-galactose with a molar ratio of 47.9:3.1:6.4:0.9:0.8. It had a backbone of 1,4-linked α-L-Rhap residues and 1,6-linked α-D-Manp residues with branches at O-3 of α-D-Manp residues. Its side chain was comprised of minor terminal ß-D-glucose and 1,4-linked α-3-O-Me-D-Galp residues terminated by α-D-galactose. Furthermore, its chain information on the values of weight-average molar mass (Mw), root mean square radius ([Formula: see text]), hydrodynamic radius (Rh) and intrinsic viscosity ([η]) for PCIPS2 were analyzed to be 3.09 × 10(4)g/mol, 7.8 nm, 3.6 nm and 8.5 mL/g, respectively. The structural exponent α of 0.57 indicated that PCIPS2 existed as a flexible chain conformation with a coil-like structure in 0.1M NaNO3 at 25 °C. In terms of known theory for worm-like chains, the model parameters for PCIPS2 were as following: molar mass per unit contour length (ML) = 379 nm(-1), persistence length (q) = 0.74 nm and hydrodynamic diameter of cylinder (d) = 0.82 nm, which were further evidenced by atomic force microscopy (AFM).

Arsenic accumulation by ferns: a field survey in southern China.

The objective of this study reported here was to characterize arsenic (As) accumulation by Pteris ferns by comparing 3 of the ferns of this genus with each other as well as with four non-Pteris ferns growing on seven sites in southern China with different As levels. A total of 112 samples, including 78 Pteris vittata, 13 P. cretica, 3 P. multifida and 18 ferns from other non-Pteris genera, with the soils in which they grew were collected for As and other elemental analyses. P. vittata was found to be the most dominant species and the most efficient As-accumulator, whereas P. multifida was the lowest As-accumulator among the Pteris ferns, with 4.54-3599, 28.7-757 and 11.2-341 mg kg(-1) As recorded in the fronds of P. vittata, P. cretica and P. multifida, respectively. Arsenic concentrations in non-Pteris ferns were generally much lower than those in Pteris ferns, with 0.81-1.32, 3.59, 10.7, 6.17-24.3 mg kg(-1) in the fronds of Blechumum orientale, Dicranopteris dichotoma, Pteridium aquilinum and Cyclosorus acuminatus, respectively. For P. vittata, the As bioaccumulation factor (ratio of As in fronds to that in soils) changed, whereas the As translocation factor (ratio of As in fronds to that in roots) remained unchanged among the different sites. The concentrations of Fe were very high in all of the collected fern sample, with the exception of B. orientale, with 207-6865, 637-3369, 375-1856, 1876, 493-6865 and 492 mg kg(-1) in the fronds of P. vittata, P. cretica, P. multifida, C. acuminatus, P. aquilinum and D. dichotoma, respectively. The association between Fe accumulation and As accumulation and tolerance in these ferns indicates the unique role of Fe in As-hyperaccumulation.