University of Westminster

About: University of Westminster is a education organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Politics. The organization has 2944 authors who have published 8426 publications receiving 200236 citations. The organization is also known as: Westminster University & Royal Polytechnic Institution.

Morphological and LSU rDNA sequence variation within the Gonyaulax spinifera-Spiniferites group (Dinophyceae) and proposal of G. elongata comb. nov. and G. membranacea comb. nov.

Abstract: Cultures were established from cysts of the cyst-based taxa Spiniferites elongatus and S. membranaceus. Motile cells and cysts from both cultures and sediment samples were examined using light and scanning electron microscopy. The cyst- theca relationship was established for S. elongatus. The motile cells have the tabulation pattern 2 pr, 4', 6'', 6c, greater than or equal to 4s, 6''', 1p, 1'''', but they remain unattributable to previously described Gonyaulax species. There was large variation in process length and process morphology in cysts from both cultures and wild samples and there was variation in ornamentation and in the development of spines and flanges in motile cells. A new combination, G. elongata (Reid) Ellegaard et al. comb. nov. is proposed, following new rules of the International Code of Botanical Nomenclature that give genera based on extant forms priority over genera based on fossil forms. Extreme morphological variation in the cyst and motile stages of S. membranaceus is described and this species is also transferred to the genus Gonyaulax, as G. membranacea (Rossignol) Ellegaard et al. comb. nov. Approximately 1500 bp of large subunit (LSU) rDNA were determined for these two species and for G. baltica, G. cf. spinifera (= S. ramosus) and G. digitalis (= Bitectatodinium tepikiense). LSU rDNA showed sequence divergences similar to those estimated between species in other genera within the Gonyaulacales; a phylogeny for the Gonyaulacales was established, including novel LSU rDNA sequences for Alexandrium margalefii, A. pseudogonyaulax and Pyrodinium bahamense var. compressum. Our results show that motile stages obtained from the germination of several cysts of the 'fossil-based' Spiniferites and B. tepikiense, which were previously attributed to 'Gonyaulax spinifera group undifferentiated', belong to distinct species of the genus Gonyaulax. These species show small morphological differences in the motile stage but relatively high sequence divergence. Moreover, this group of species is monophyletic, supported by bootstrap values of 100% in parsimony and maximum likelihood analyses. Copyright © (2003) International Phycological Society. Reprinted by permission of Alliance Communications Group, a division of Allen Press, Inc.

Purification and biochemical properties of a galactooligosaccharide producing β-galactosidase from Bullera singularis

Abstract: A β-galactosidase, catalyzing lactose hydrolysis and galactooligosaccharide (GalOS) synthesis from lactose, was extracted from the yeast, Bullera singularis KCTC 7534. The crude enzyme had a high transgalactosylation activity resulting in the oligosaccharide conversion of over 34% using pure lactose and cheese whey permeate as substrates. The enzyme was purified by two chromatographic steps giving 96-fold purification with a yield of 16%. The molecular weight of the purified enzyme (specific activity of 56 U mg−1) was approx. 53 000 Da. The hydrolytic activity was the highest at pH 5 and 50 °C, and was stable to 45 °C for 2 h. Enzyme activity was inhibited by 10 mM Ag3+ and 10 mM SDS. The K m for lactose hydrolysis was 0.58 m and the maximum reaction velocity (V max) was 4 mm min−1. GalOS, including tri- and tetra-saccharides were produced with a conversion yield of 50%, corresponding to 90 g GalOS l−1 from 180 g lactose l−1 by the purified enzyme.

Requirement of transforming growth factor beta-activated kinase 1 for transforming growth factor beta-induced alpha-smooth muscle actin expression and extracellular matrix contraction in fibroblasts.

Abstract: Objective. Fibrosis is believed to occur through normal tissue remodeling failing to terminate. Tissue repair intimately involves the ability of fibroblasts to contract extracellular matrix (ECM), and enhanced ECM contraction is a hallmark of fibrotic cells in various conditions, including scleroderma. Some fibrogenic transcriptional responses to transforming growth factor beta (TGF beta), including alpha-smooth muscle actin (alpha-SMA) expression and ECM contraction, require focal adhesion kinase/Src (FAK/Src). The present study was undertaken to assess whether TGF beta-activated kinase I (TAK1) acts downstream of FAK/Src to mediate fibrogenic responses in fibroblasts.Methods. We used microarray, real-time polymerase chain reaction, Western blot, and collagen gel contraction assays to assess the ability of wild-type and TAK1-knockout fibroblasts to respond to TGF beta 1.Results. The ability of TGF to induce TAK1 was blocked by the FAK/Src inhibitor PP2. JNK phosphorylation in response to TGF beta 1 was impaired in the absence of TAK1. TGF beta could not induce matrix contraction or expression of a group of fibrotic genes, including alpha-SMA, in the absence of TAK1.Conclusion. These results suggest that TAK1 operates downstream of FAK/Src in mediating fibrogenic responses and that targeting of TAK1 may be a viable antifibrotic strategy in the treatment of certain disorders, including scleroderma.