Purification and characterization of dermatan sulfate from the skin of the eel,Anguilla japonica

Glycosaminoglycans were isolated from the eel skin (Anguilla japonica) by actinase and endonuclease digestions, followed by a beta-elimination reaction and DEAE-Sephacel chromatography. Dermatan sulfate was the major glycosaminoglycan in the eel skin with 88% of the total uronic acid. The content of the IdoA2Salpha1-->4GalNAc4S sequence in eel skin, which shows anticoagulant activity through binding to heparin cofactor II, was two times higher than that of dermatan sulfate from porcine skin. The anti-IIa activity of eel skin dermatan sulfate was determined to be 2.4 units/mg, whereas dermatan sulfate from porcine skin shows 23.2 units/mg. The average molecular weight of dermatan sulfate was determined by gel chromatography on a TSKgel G3000SWXL column as 14 kDa. Based on 1H NMR spectroscopy, the presence of 3-sulfated and/or 2,3-sulfated IdoA residues was suggested. The reason why highly sulfated dermatan sulfate does not show anticoagulant activity is discussed. In addition to dermatan sulfate, the eel skin contained a small amount of keratan sulfate, which was identified by keratanase treatment.     

AXR1 is involved in BR-mediated elongation and SAUR-AC1 gene expression in Arabidopsis

Limited information is available concerning the interactions between the brassinosteroid (BR) and auxin signaling pathways. The expression pattern of the SAUR-AC1 gene, an early auxin-inducible gene in Arabidopsis, was studied in response to brassinolide (BL), in the presence of a BR-biosynthesis inhibitor, in a BR-deficient mutant, and in combination with auxin. The results suggested that the SAUR-AC1 gene is regulated by BRs independently of auxin levels, and that it is important in BR-mediated elongation. The axr1 (auxin insensitive 1) mutant was less sensitive to BL-induced elongation and BL-induced SAUR-AC1 expression, suggesting that a ubiquitin ligase-mediated system is involved in BR-mediated elongation.     

TGF-beta receptor kinase inhibitor enhances growth and integrity of embryonic stem cell-derived endothelial cells

Recent findings have shown that embryonic vascular progenitor cells are capable of differentiating into mural and endothelial cells. However, the molecular mechanisms that regulate their differentiation, proliferation, and endothelial sheet formation remain to be elucidated. Here, we show that members of the transforming growth factor (TGF)-beta superfamily play important roles during differentiation of vascular progenitor cells derived from mouse embryonic stem cells (ESCs) and from 8.5-days postcoitum embryos. TGF-beta and activin inhibited proliferation and sheet formation of endothelial cells. Interestingly, SB-431542, a synthetic molecule that inhibits the kinases of receptors for TGF-beta and activin, facilitated proliferation and sheet formation of ESC-derived endothelial cells. Moreover, SB-431542 up-regulated the expression of claudin-5, an endothelial specific component of tight junctions. These results suggest that endogenous TGF-beta/activin signals play important roles in regulating vascular growth and permeability.     

Comparative study of the N-terminal hydrophilic region in Streptomyces lividans and E. coli FtsY

Streptomyces lividans FtsY (SlFtsY) was cloned and overexpressed in Escherichia coli. Analysis of the amino acid (aa) sequence showed a concentration of hydrophilic aa's in the N-terminal half region of SlFtsY as observed in that of E. coli FtsY (EcFtsY). However, the length of the hydrophilic region was shorter in SlFtsY than in EcFtsY. Overexpression of SlFtsY in E. coli resulted in growth suppression as in the case of the overexpression of EcFtsY, while growth suppression as a result of the overexpression of the C-terminal half region of SlFtsY was limited. This result suggests that the N-terminal hydrophilic region of SlFtsY, regardless of its short length, would behave like its counterpart region of EcFtsY in E. coli.     

Preparation of antiserum against rat delta6-desaturase and its use to evaluate the desaturase protein levels in rats treated with gemfibrozil,a ligand for peroxisome proliferator-activated receptor alpha

Anti-rat delta6-desaturase serum was produced by immunizing rabbits with the 14 N-terminal amino acids (2-15) of rat delta6-desaturase. The antiserum prevented the enzymatic activity of delta6-desaturase in microsomes. Subsequently, the antiserum was used to demonstrate that gemfibrozil, a ligand for peroxisome proliferator-activated receptor alpha, is involved in activating delta6-desaturase gene expression, thereby elevating the protein level and the activity.