Was reported by an

This report deals with the mechanism of the final breakdown of polymeric power cables which have been degraded by water trees. Water treeing is one of the major degradation mechanisms in cable insulation. It has been believed that the final breakdown takes place when a water tree penetrates the insulation. In order to reproduce penetrating water trees in a film specimen, a double layer specimen with low-density polyethylene films was subjected to an aging test to generate water trees.

6p 12120609 01-06-2020 13 1   Download

The Toyota Motor Corporation was founded in 1937 by Kiichiro Toyoda. It originally started as a subsidiary of his father’s company Toyoda Industries. The first vehicle, the Toyota AA, was produced in 1936 whilst the company was still associated with Toyoda. The brand as we know it became established as an independent company in 1937 and changed their name to Toyota. The name change was implemented to signify a separation of work and home, to simplify the pronunciation and because it only took 8 brush strokes (which is considered lucky) to write in Japanese.

26p grace_lady 12-07-2013 383 47   Download

In the course of trying to understand the pathogenesis of leishmaniasis in relation to extracellular matrix (ECM) elements, laminin, a major ECM protein, has been found to bind saturably and with high affinity to a 67-kDa cell surface protein of Leishmania donovani. This interaction involves a single class of binding sites, which are ionic in nature, conformation-dependent and possibly involves sulfhydryls. Binding activity was significantly enhanced by Zn2+, an effect possibly mediated through Cys-rich zinc finger-like sequences on laminin....

8p system191 01-06-2013 41 4   Download

Shikimate kinase was chosen as a convenient representative example of the subclass of a/b proteins with which to examine the mechanism of protein folding. In this paper we report on the refolding of the enzyme after denaturation in urea. As shown by the changes in secondary and tertiary structure monitored by far UV circular dichroism (CD) and fluorescence, respectively, the enzyme was fully unfolded in 4 M urea. From an analysis of the unfolding curve in terms of the two-state model, the stability of the folded state could be estimated as 17 kJÆmol)1.

9p system191 01-06-2013 46 5   Download

Certain amino acids, like glutamine and leucine, induce an anabolic response in liver. They activate p70 ribosomal protein S6 kinase (p70S6K) and acetyl-CoA carboxylase (ACC) involved in protein and fatty acids synthesis, respectively. In contrast, the AMP-activated protein kinase (AMPK), which senses the energy state of the cell and becomes activated under metabolic stress, inactivates by phosphorylation key enzymes in biosynthetic pathways thereby conserving ATP.

9p system191 01-06-2013 50 5   Download

An unconventional phospholipase D (PLD) activity was identified recently in Saccharomyces cerevisiae which is Ca2+-dependent, preferentially hydrolyses phosphatidylethanolamine (PtdEtn) and phosphatidylserine and does not catalyse a transphosphatidylation with primary short-chain alcohols. We have characterized the cytosolic and membrane-bound forms of the yeast PtdEtn-PLD and examined the regulation of its activity under certain growth, nutritional and stress conditions. Both forms of PtdEtn-PLD activity were similarly activated by Ca2+ ions in a biphasic manner.

10p system191 01-06-2013 36 4   Download

Visual arrestin is converted from a ÔbasalÕ state to an ÔactivatedÕ state by interaction with the phosphorylated C-terminus of photoactivated rhodopsin (R*), but the conformational changes in arrestin that lead to activation are unknown. Small-angle X-ray scattering (SAXS) was used to investigate the solution structure of arrestin and characterize changes attendant upon activation. Wild-type arrestin forms dimers with a dissociation constant of 60 lM.

9p system191 01-06-2013 53 3   Download

We report here the direct evidence for the formation of alternative DNA structures in a plasmid DNA, termed pTIR10, containing a 0.23-kb pyrimidine/purine-biased (Pyr/Pur) stretch isolated from the rat genome. Long Pyr/Pur sequences are abundant in eukaryotic genomes, and they may modulate the biological activity of genes and genomes via formation of various types of triplex-related structures. The plasmid DNA in sodium acetate buffer (pH 4.35) was deposited on APS-modified mica, and after drying it was imaged with an atomic force microscope in air. ...

5p system191 01-06-2013 34 3   Download

A recombinant lipase cloned from Pseudomonas fragi strain IFO 3458 (PFL) was found to retain significant activity at low temperature. In an attempt to elucidate the structural basis of this behaviour, a model of its three-dimensional structure was built by homology and compared with homologous mesophilic lipases, i.e. the Pseudomonas aeruginosa lipase (45% sequence identity) and Burkholderia cepacia lipase (38%).

8p system191 01-06-2013 48 4   Download

The synthesis of 10 new phosphoenolpyruvate (PEP) analogues with modifications in the phosphate and the carboxylate function is described. Included are two potential irreversible inhibitors of PEP-utilizing enzymes. One incorporates a reactive chloromethylphosphonate function replacing the phosphate group of PEP. The second contains a chloromethyl group substituting for the carboxylate function of PEP. An improved procedure for the preparation of the known (Z)- and (E)-3-chloro-PEP is also given.

11p system191 01-06-2013 35 3   Download

An immuno-homologue of maize Ca2+/calmodulin (CaM)dependent protein kinase with a molecular mass of 72 kDa was identified in pea. The pea kinase (PsCCaMK) was upregulated in roots in response to low temperature and increased salinity. Exogenous Ca2+ application increased the kinase level and the response was faster than that obtained following stress application. Low temperaturemediated, but not salinity-mediated stress kinase increase was inhibited by the application of EGTA and W7, a CaM inhibitor....

12p system191 01-06-2013 39 5   Download

The plant enzyme phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) shows homology to histidine ammonia-lyase (HAL) whose structure has been solved by X-ray crystallography. Based on amino-acid sequence alignment of the two enzymes, mutagenesis was performed on amino-acid residues that were identical or similar to the active site residues in HAL to gain insight into the importance of this residues in PAL for substrate binding or catalysis. We mutated the following amino-acid residues: S203, R354, Y110, Y351, N260, Q348, F400, Q488 and L138....

11p system191 01-06-2013 65 4   Download

Many groups of proteins play important roles in the cell’s response to various stresses. The molecular chaperone GroEL of Escherichia coli represents one such highly conserved family of stress proteins. We have observed that isolated GroEL complexes from stationary cultures contain various polypeptides that can be released from the chaperonin by GroES and/or ATP, and identified two such polypeptides as the proteins GatY and UP12.

9p system191 01-06-2013 28 3   Download

Microcalorimetry and UV-vis spectroscopy were used to conduct thermodynamic and kinetic investigations of the scission of calf thymus DNA catalyzed by bleomycin A5 (BLM-A5) in the presence of ferrous ion and oxygen. The molar reaction enthalpy for the cleavage, the Michaelis– Menten constant for calf thymus DNA and the turnover number of BLM-A5 were calculated by a novel thermokinetic method for an enzyme-catalyzed reaction to be )577 ± 19 kJÆmol)1, 20.4 ± 3.8 lM and 2.28 ± 0.49 · 10)2 s)1, respectively, at 37.0 °C. This DNA cleavage was a largely exothermic reaction....

9p system191 01-06-2013 31 4   Download

Cys341 of carboxypeptidase Y, which constitutes one side of the solvent-accessible surface of the S1 binding pocket, was replaced with Gly, Ser, Asp, Val, Phe or His by site-directed mutagenesis. Kinetic analysis, using Cbz-dipeptide substrates, revealed that polar amino acids at the 341 position increased Km whereas hydrophobic amino acids in this position tended to decrease Km.

6p system191 01-06-2013 40 4   Download

An oxidosqualene cyclase cDNA, LcIMS1, was isolated from cultured cells of Luffa cylindrica Roem. by heterologous hybridization with cDNA of Glycyrrhiza glabra b-amyrin synthase. Expression of LcIMS1 in yeast lacking endogenous oxidosqualene cyclase activity resulted in the accumulation of isomultiflorenol, a triterpene. This is consistent with LcIMS1 encoding isomultiflorenol synthase, an oxidosqualene cyclase involved in bryonolic acid biosynthesis in cultured Luffa cells.

7p system191 01-06-2013 50 5   Download

The in vitro activities of purified potato starch branching enzyme (SBE) I and II expressed in Escherichia coli were compared using several assay methods. With the starch– iodine method, it was found that SBE I was more active than SBE II on an amylose substrate, whereas SBE II was more active than SBE I on an amylopectin substrate. Both enzymes were stimulated by the presence of phosphate.

6p system191 01-06-2013 48 4   Download

Frog p26olf is a novel S100-like Ca21-binding protein found in olfactory cilia. It consists of two S100-like domains aligned sequentially, and has a total of four Ca21-binding sites (known as EF-hands). In this study, to elucidate the mechanism of Ca21-binding to each EF-hand (named EF-A, -B, -C and -D from the N-terminus of p26olf), we examined Ca21-binding in wild-type p26olf and also in its mutants in which a glutamate at the –z coordinate position within each Ca21-binding loop was substituted for a glutamine.

8p system191 01-06-2013 29 4   Download

The regulator of ubiquitous kinase (Ruk) protein, also known as CIN85 or SETA, is an adaptor-type protein belonging to the CD2AP/CMS family. It was found in complexes with many signaling proteins, including phos1 phoinositol (PtdIns) 3-kinase (EC 2.7.1.137), Cbl, GRB2, p130Cas and Crk. Functional analysis of these interactions, implicated Ruk in the regulation of apoptosis, receptor endocytosis and cytoskeletal rearrangements.

7p research12 01-06-2013 27 4   Download

Transglutaminase (TGase) catalyses the post-translational modification of proteins by transamidation of available glutamine residues. While several TGase genes of fish and arthropods have been cloned and appear to have similar structures to those of mammals, no homologous gene has been found in lower eukaryotes. We have cloned the acellular slime mold Physarum polycephalum TGase cDNA using RT-PCR with degenerated primers, based on the partial amino acid sequence of the purified enzyme. The cDNA contained a 2565-bp ORF encoding a 855-residue polypeptide.

10p research12 01-06-2013 48 4   Download