Medical reports

Epigenetic defects (gain or loss of DNA methylation) of the human ICR1 11p15 domain result in two opposite foetal growth disorders (BWS and SRS) depending on which parental allele is affected. A few deletions within ICR1 have been reported in familial BWS cases with ICR1 gain of methylation, however the mechanism(s) of the DNA methylation defects at ICR1 remains largely unknown in most BWS and SRS patients.

83p runthenight07 01-03-2023 9 3   Download

The study acknowledges some limitations such as a conclusion section as well as the order of the moves is still neglected. In addition, there is a lack of the MCRs written in English by Vietnamese authors. Despite these limitations, the study is hoped to provide some pedagogical implications for teaching writing in Vietnamese settings to encourage student to be aware of the moves when writing a MCR.

30p kethamoi2 14-12-2019 35 2   Download

The dinitrogenase component proteins of the conventional Mo nitrogenase (MoFe protein) and of the alternative Fe-only nitrogenase (FeFe protein) were both isolated and purified from Rhodobacter capsulatus, redox-titrated according to the same procedures and subjected to an EPR spectroscopic comparison. In the course of an oxidative titration of the MoFe protein (Rc1Mo) three significant S ¼ 1/2 EPR signals deriving from oxidized states of the P-cluster were detected: (1) a rhombic signal (g ¼ 2.07, 1.96 and 1.

12p system191 01-06-2013 31 4   Download

DNA of prokaryotes is in a nonequilibrium structural state, characterized as ÔactiveÕ DNA supercoiling. Alterations in this state a€ect many life processes and a homeostatic control of DNA supercoiling has been suggested [Menzel, R. & Gellert, M. (1983) Cell 34, 105±113]. We here report on a new method for quantifying homeostatic control of the high-energy state of in vivo DNA. The method involves making small perturbation in the expression of topoisomerase I, and measuring the e€ect on DNA supercoiling of a reporter plasmid and on the expression of DNA gyrase....

8p system191 01-06-2013 34 5   Download

The importance of two putative Zn2+-binding (Asp347, Glu429) and two catalytic (Arg431, Lys354) residues in the tomato leucine aminopeptidase (LAP-A) function was tested. The impact of substitutions at these positions, corresponding to the bovine LAP residues Asp255, Glu334, Arg336, and Lys262, was evaluated in His6–LAP-A fusion proteins expressed in Escherichia coli. Sixty-five percent of the mutant His6–LAP-A proteins were unstable or had complete or partial defects in hexamer assembly or stability. The activity of hexameric His6–LAP-As on Xaa-Leu and Leu-Xaa dipeptides was tested.

11p system191 01-06-2013 39 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

FTIR spectroscopy has been applied to study the coordination structures of Mg2þ and Ca2þ ions bound in Akazara scallop troponin C (TnC), which contains only a single Ca2þ binding site. The region of the COO – antisymmetric stretch provides information about the coordination modes of COO – groups to the metal ions: bidentate, unidentate, or pseudo-bridging. Two bands were observed at 1584 and 1567 cm21 in the apo state, whereas additional bands were observed at 1543 and 1601 cm21 in the Ca2þ-bound and Mg2þ-bound states, respectively.

7p system191 01-06-2013 40 2   Download

Cannabinoid receptors and their endogenous ligands, the endocannabinoids, have been detected in several blood immune cells, including monocytes/macrophages, basophils and lymphocytes. However, their presence in dendritic cells, which play a key role in the initiation and development of the immune response, has never been investigated.

8p system191 01-06-2013 28 4   Download

The transcription factor serum response factor (SRF) regulates expression of growth factor-dependent genes and muscle-specific genes in vertebrates. Homologous factors regulate differentiation of some ectodermic tissues in invertebrates. To explore the molecular basis of these different physiological functions, the functionality of human, Drosophila melanogaster and Artemia franciscana SRFs in mammalian cells has been compared in this article. D. melanogaster and, to a lesser extend, A.

9p system191 01-06-2013 32 5   Download

In this study we describe the isolation of three genes of the CYP11B family of the guinea pig. CYP11B1 codes for the previously described 11b-hydroxylase [Bulow, H.E., Mobius, ¨ ¨ K., Bahr, V. & Bernhardt, R. (1996) Biochem. Biophys. Res. ¨ Commun. 221, 304–312] while CYP11B2 represents the aldosterone synthase gene. As no expression for CYP11B3 was detected this gene might represent a pseudogene.

9p system191 01-06-2013 38 3   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

Liver metabolism is influenced by hormones and nutrients. Amino acids such as glutamine or leucine induce an anabolic response, which resembles that of insulin in muscle and adipose tissue. In this work, the signalling pathways and the effects of insulin were compared to those of glutamine and leucine in isolated hepatocytes from normal and streptozotocin-diabetic rats.

9p system191 01-06-2013 46 5   Download

The human immunodeficiency virus type 1, HIV-1, genome encodes a highly conserved regulatory gene product, Vpr (96 amino acids), which is incorporated into virions in quantities equivalent to those of the viral Gag protein. In infected cells, Vpr is believed to function during the early stages of HIV-1 replication (such as transcription of the proviral genome and migration of preintegration nuclear complex), blocks cells in G2 phase and triggers apoptosis.

10p system191 01-06-2013 45 4   Download

Amplification of N-myc oncogene is a frequent event in advanced stages of human neuroblastoma and correlates with poor prognosis and enhanced neovascularization. Angiogenesis is an indispensable prerequisite for the progression and metastasis of solid malignancies, which is modulated by tumor suppressors and oncogenes. We have addressed the possibility that N-myc oncogene might regulate angiogenesis in neuroblastoma. Here, we report that experimental N-Myc overexpression results in down-regulation of leukemia inhibitory factor (LIF), a modulator of endothelial cell proliferation....

10p system191 01-06-2013 34 4   Download

Bacteroides vulgatus has been shown to be involved in the aggravation of colitis. Previously, we separated two potent virulence factors, capsular polysaccharide (CPS) and lipopolysaccharide (LPS), from a clinical isolate of B. vulgatus and characterized the structure of CPS. In this study, we elucidated the structures of O-antigen polysaccharide (OPS) and lipid A in the LPS. LPS was subjected to weak acid hydrolysis to produce the lipid A fraction and polysaccharide fraction.

7p system191 01-06-2013 50 8   Download

Many biological C-H activation reactions exhibit nonclassical kinetic isotope effects (KIEs). These nonclassical KIEs are too large (kH/kD 7) and/or exhibit unusual temperature dependence such that the Arrhenius prefactor KIEs (AH/AD) fall outside of the semiclassical range near unity. The focus of this minireview is to discuss such KIEs within the context of the environmentally coupled hydrogen tunneling model.

9p system191 01-06-2013 37 4   Download

Department of Medical Biochemistry and Biology, University of Bari, Italy; 2Department of Zoology, Laboratory of Histology and Comparative Anatomy, University of Bari, Italy; 3Center for the Study of Mitochondria and Energy Metabolism (CNR) Bari, Italy Mitochondrial bioenergetic impairment has been found in the organelles isolated from rat liver during the prereplicative phase of liver regeneration.

9p system191 01-06-2013 35 4   Download

Pyruvate decarboxylase (EC 4.1.1.1) was isolated and purified from the yeast Kluyveromyces lactis. The properties of this enzyme relating to the native oligomeric state, the subunit size, the nucleotide sequence of the coding gene(s), the catalytic activity, and protein fluorescence as well as circular dichroism are very similar to those of the well characterized pyruvate decarboxylase species from yeast.

8p system191 01-06-2013 41 3   Download

Guanosine triphosphate nucleotide analogues such as GppNHp (also named GMPPNP) or GTPcS are widely used to stabilize rapidly hydrolyzing protein-nucleotide complexes and to investigate biochemical reaction pathways. Here we describe the chemical synthesis of guanosine 5¢-O-(c-amidotriphosphate) (GTPcNH2) and a new synthesis of guanosine 5¢-O-(c-fluorotriphosphate) (GTPcF). The two nucleotides were characterized using NMR spectroscopy and isothermal titration calorimetry. Chemical shift data on 31P, 19F and 1H NMR resonances are tabulated.

9p system191 01-06-2013 32 5   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 34 3   Download