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Fucose-Rich Sulfated Polysaccharides from Two Vietnamese Sea Cucumbers Bohadschia argus and Holothuria (Theelothuria) spinifera: Structures and Anticoagulant Activity

Fucosylated chondroitin sulfates (FCSs) FCS-BA and FCS-HS, as well as fucan sulfates (FSs) FS-BA-AT and FS-HS-AT were isolated from the sea cucumbers Bohadschia argus and Holothuria (Theelothuria) spinifera, respectively. Purification of the polysaccharides was carried out by anion-exchange chromatography on DEAE-Sephacel column. Structural characterization of polysaccharides was performed in terms of monosaccharide and sulfate content, as well as using a series of non-destructive NMR spectroscopic methods. Both FCSs were shown to contain a chondroitin core [→3)-β-d-GalNAc-(1→4)-β-d-GlcA-(1→]_n bearing sulfated fucosyl branches at O-3 of every GlcA residue in the chain. These fucosyl residues were different in pattern of sulfation: FCS-BA contained Fuc2S4S, Fuc3S4S and Fuc4S at a ratio of 1:8:2, while FCS-HS contained these residues at a ratio of 2:2:1. Polysaccharides differed also in content of GalNAc4S6S and GalNAc4S units, the ratios being 14:1 for FCS-BA and 4:1 for FCS-HS. Both FCSs demonstrated significant anticoagulant activity in clotting time assay and potentiated inhibition of thrombin, but not of factor Xa. FS-BA-AT was shown to be a regular linear polymer of 4-linked α-L-fucopyranose 3-sulfate, the structure being confirmed by NMR spectra of desulfated polysaccharide. In spite of considerable sulfate content, FS-BA-AT was practically devoid of anticoagulant activity. FS-HS-AT cannot be purified completely from contamination of some FCS. Its structure was tentatively represented as a mixture of chains identical with FS-BA-AT and other chains built up of randomly sulfated alternating 4- and 3-linked α-L-fucopyranose residues.     

Movement and Distribution of Cryptolestes ferrugineus (Coleoptera: Laemophloeidae) Adults Under Different Temperature Differences in Different Lengths of Horizontal Grain Columns

Understanding insect movement and distribution is critical for developing an effective insect pest management protocol. Movement and distribution of adult Cryptolestes ferrugineus (Stephens) in response to nominal temperature differences of 5, 10, 15, and 20°C in 1- and 2-m horizontal columns filled with 12.5% moisture content wheat were studied in 24, 48, and 72 h of movement times. In the wheat columns without temperature differences, adults had a diffusion distribution pattern caused by their random movement. Adults showed bias movement to the warmer grain in wheat columns with temperature differences and preferred the warmer grain regardless of the magnitude of temperature differences in less than 24 h. Their distribution did not have significant differences among different movement times in 1- or 2-m columns. About 40% of adults moved to the warmer wheat located at 0.4 to 0.5 m in the 1 m column but did not move to the warmer wheat located at 0.9 to 1 m in the 2-m column. Therefore, length of grain column influenced detection of warmer grain by insects. Adults under different temperatures had a similar response as that under linear temperature gradients.     

A comparison of three rapid diagnostic methods for the detection of rotavirus infection in calves

Three techniques for the detection of rotavirus in faecal samples from calves with neonatal gastroenteritis were compared. A preliminary study indicated that reverse passive haemagglutination (RPHA) was at least as sensitive as the enzyme-linked immunosorbent assay (ELISA). These two immunoassays were compared with the detection of viral RNA by polyacrylamide gel electrophoresis (PAGE) on 209 field samples. Of the 77 samples in which at least one test gave a positive result, 69 were positive by both RPHA and PAGE, but only 49 were also positive by ELISA, indicating a lower sensitivity for the latter test. The overall agreement between RPHA and PAGE was 96%. The reasons for the discrepancies between the tests are discussed.