34 research outputs found
Role of vascular endothelial growth factor and other growth factors in post-stroke recovery
No full textStroke is a major health problem world-wide and its burden has been rising in last few decades. Until now tissue plasminogen activator is only approved treatment for stroke. Angiogenesis plays a vital role for striatal neurogenesis after stroke. Administration of various growth factors in an early post ischemic phase, stimulate both angiogenesis and neurogenesis and lead to improved functional recovery after stroke. However vascular endothelial growth factors (VEGF) is the most potent angiogenic factor for neurovascularization and neurogenesis in ischemic injury can be modulated in different ways and thus can be used as therapy in stroke. In response to the ischemic injury VEGF is released by endothelial cells through natural mechanism and leads to angiogenesis and vascularization. This release can also be up regulated by exogenous administration of Mesenchymal stem cells, by various physical therapy regimes and electroacupuncture, which further potentiate the efficacy of VEGF as therapy in post stroke recovery. Recent published literature was searched using PubMed and Google for the article reporting on methods of up regulation of VEGF and therapeutic potential of growth factors in stroke
Biochemical Characterization of DDX43 (HAGE) Helicase
No full textDDX43, DEAD-box polypeptide 43, also known as HAGE (helicase antigen gene), is a member of the DEAD-box family of RNA helicases. It is highly expressed in many tumor types compared with normal tissues, and is therefore considered as a potential target for immunotherapy of cancers. Despite its unique expression and potential as a therapy target, little is known about its biochemical and physiological functions. In this study, we purified recombinant DDX43 protein to near homogeneity and our gel filtration results showed that DDX43 exists as a monomer in solution. Biochemical assays using monomer fractions of DDX43 demonstrated that it could unwind both RNA and DNA substrates in an ATP-dependent manner, and most efficiently in the presence of Mg2+; no significant unwinding activity was detected with other nucleoside triphosphates or divalent cations. Replacing the conserved lysine in motif I (K292A) or aspartic acid in motif II (D396A) abolished the unwinding activity. Intriguingly, DDX43 could unwind RNA substrates without strict polarity, but it showed higher unwinding activity on a 5’ tail RNA substrate compared to a 3’ tail or blunt end RNA substrates. However, for DNA substrates, it exhibited unidirectional translocation and unwound DNA in a 3’to 5’ direction only. A K-homology (KH) domain in the N-terminal region of DDX43 was found to possess strong nucleic acid binding ability and the N-terminal domain showed novel strand exchange and required for the unwinding activity. Compared to the full-length protein, the C-terminal helicase domain had weaker unwinding activity, but an increase was observed in the presence of the N-terminal domain. Using Co-immunoprecipitation and mass spectrometry, we found that DDX43 associates with pICln and MEP50, two methylosome subunits that are involved in assembly of the spliceosome complex. Collectively, our results suggest that DDX43 is a KH domain containing ATP-dependent dual helicase, where unwinding activity is mediated through cooperation between its N-terminal domain and helicase domain, and potentially involved in pre-mRNA splicing
Impact of migrant remittances on fertility and education in the source community: empirical evidence from India
No full textThis dissertation studies the impact of migrant remittances on two measures of human development- fertility and education. Remittances help recipient households to earn extra income and increase their standards of living over time. If by augmenting household income, remittances lead to an increase in the number of children in the household, the long term development impact of remittances will be undermined. Comparatively, if remittance incomes allow households to spend more on the education of each child in the household, it will be better for the migrant-sending household in terms of long term development. The two essays in this dissertation attempt to evaluate the impact of remittances on fertility and the impact of remittances on education expenditures made by remittance receiving households, and compare these outcomes with households that do not receive remittances. The dataset used for this analysis is the 64th Round of National Sample Survey conducted by the Government of India. It is seen that remittance incomes lead to a lower probability of birth in the remittance receiving household while increasing the share of education related expenditures in the household and education investments in each child, which are desirable outcomes for a developing community characterized by high population and low human capital.Ph. D.Includes bibliographical referencesIncludes vitaby Tanu Kohl
The Q Motif Is Involved in DNA Binding but Not ATP Binding in ChlR1 Helicase.
No full textHelicases are molecular motors that couple the energy of ATP hydrolysis to the unwinding of structured DNA or RNA and chromatin remodeling. The conversion of energy derived from ATP hydrolysis into unwinding and remodeling is coordinated by seven sequence motifs (I, Ia, II, III, IV, V, and VI). The Q motif, consisting of nine amino acids (GFXXPXPIQ) with an invariant glutamine (Q) residue, has been identified in some, but not all helicases. Compared to the seven well-recognized conserved helicase motifs, the role of the Q motif is less acknowledged. Mutations in the human ChlR1 (DDX11) gene are associated with a unique genetic disorder known as Warsaw Breakage Syndrome, which is characterized by cellular defects in genome maintenance. To examine the roles of the Q motif in ChlR1 helicase, we performed site directed mutagenesis of glutamine to alanine at residue 23 in the Q motif of ChlR1. ChlR1 recombinant protein was overexpressed and purified from HEK293T cells. ChlR1-Q23A mutant abolished the helicase activity of ChlR1 and displayed reduced DNA binding ability. The mutant showed impaired ATPase activity but normal ATP binding. A thermal shift assay revealed that ChlR1-Q23A has a melting point value similar to ChlR1-WT. Partial proteolysis mapping demonstrated that ChlR1-WT and Q23A have a similar globular structure, although some subtle conformational differences in these two proteins are evident. Finally, we found ChlR1 exists and functions as a monomer in solution, which is different from FANCJ, in which the Q motif is involved in protein dimerization. Taken together, our results suggest that the Q motif is involved in DNA binding but not ATP binding in ChlR1 helicase
The Current Situation and Prospect Of Study Quality Evaluation Research in China in The Last 10 Years
No full textWith the deepening of China's educational reform, the evaluation of teaching quality has become an important aspect of teaching reform.And the evaluation of students'learning quality is an important part of teaching evaluation. Research on it will help to improve the teaching quality of our country and promote the overall improvement of students' morality, intelligence, physical fitness and beauty.Therefore, this study takes 108 literatures related to the study of learning quality evaluation in China as the research object, uses content analysis method, carries out statistical analysis on the annual number of literatures, Journal distribution, author status, paper influence, research content, etc., analyzes the current situation and existing problems of the study of learning quality evaluation in China, and puts forward the need for further deepening.On the basis of these questions, possible future research directions are proposed
ChlR1-Q23A fails to unwind DNA triple helixes.
No full text<p><b>(A-B)</b> Helicase reactions (20 μL) were performed by incubating the indicated ChlR1-WT (<b>A</b>) or ChlR1-Q23A (<b>B</b>) concentrations with 0.5 nM 5’ tail plasmid-triplex substrate at 37°C for 20 min under standard helicase assay conditions as described in “Materials and methods”. Triangle indicates heat-denatured DNA substrate control.</p
Determination of ChlR1 protein oligomerization state.
No full text<p>(<b>A</b>) Coomassie blue stained SDS-PAGE gel showing the ChlR1-WT protein. (<b>B</b>) Chromatographic profiles of ChlR1-WT protein from a HiPrep 16/60 Sephacryl S-300 HR column. (<b>C</b>) Chromatographic profiles of standard proteins on a HiPrep 16/60 Sephacryl S-300 HR column. The equation of protein molecular weight is shown in the upper right corner. (<b>D</b>) Fourteen fractions were selected from the peak area and analyzed by 10% SDS-PAGE. The gel was stained with Coomassie blue. (<b>E</b>) The fractions in D were immunoblotted with an anti-FLAG antibody. (<b>F</b>) Total protein before size exclusion chromatography (SEC), and fractions 4 and 5 after SEC, were subjected to helicase assay using 0.5 nM duplex DNA substrate.</p
ATP hydrolysis and ATP binding assays of ChlR1 proteins.
No full text<p>(<b>A</b>) A representative image of ChlR1 ATP hydrolysis detected by TLC. (<b>B</b>) ATP binding by ChlR1 proteins was determined by ATP agarose (Jena Bioscience) as described in “Materials and methods”, followed by Western blot with an anti-FLAG antibody. (<b>C</b>) ATP binding by wild-type ChlR1 and mutant protein. α<sup>32</sup>P-ATP binding to ChlR1-WT and ChlR1-Q23A was performed by gel filtration chromatography as described in “Materials and methods”. The same amount of protein was used, and the total amount of bound ATP was divided by protein and presented as fmol ATP per pmol protein. BSA was used as a control. (<b>D</b>) A representative image of filter dot blot assays of ChlR1 proteins binding α<sup>32</sup>P-ATP. (<b>E</b>) Quantitative analyses of ATP bound to ChlR1 proteins in panel D. Data represent the mean of at least three independent experiments with SD indicated by error bars.</p
Helicase analysis of ChlR1 proteins on forked duplex DNA and G4 DNA.
No full text<p>Helicase reactions were performed by incubating with indicated protein concentration and 0.5 nM duplex DNA substrate (<b>A-B</b>) or OX-1 G2’ DNA substrate (<b>C-D</b>) at 37°C for 20 min. The triangle indicates heat denatured DNA substrate control.</p
SDS-PAGE analysis of ChlR1 proteins by sucrose gradient fractions.
No full text<p>Coomassie blue-stained gels of protein standards (<b>A</b>), and silver staining of ChlR1-WT (<b>B</b>) and ChlR1-Q23A (<b>C</b>) from the sucrose gradient centrifugation. Thirty (30) μL of the sucrose-adjusted fractions (1–28) were loaded per lane. The positions of carbonic anhydrase (29 kDa), BSA (66 kDa), and alcohol dehydrogenase (150 kDa) are indicated at the top. Note that alcohol dehydrogenase is a homotetramer, and is shown in subunits of 37.7 kDa after denaturing.</p
