15 research outputs found
Extremal inverse eigenvalue problem for matrices described by a connected unicyclic graph
No full textsummary:In this paper, we deal with the construction of symmetric matrix whose corresponding graph is connected and unicyclic using some pre-assigned spectral data. Spectral data for the problem consist of the smallest and the largest eigenvalues of each leading principal submatrices. Inverse eigenvalue problem (IEP) with this set of spectral data is generally known as the extremal IEP. We use a standard scheme of labeling the vertices of the graph, which helps in getting a simple relation between the characteristic polynomials of each leading principal submatrix. Sufficient condition for the existence of the solution is obtained. The proof is constructive, hence provides an algorithmic procedure for finding the required matrix. Furthermore, we provide the condition under which the same problem is solvable when two particular entries of the required matrix satisfy a linear relation
Two inverse eigenvalue problems for matrices whose graphs are trees
No full textAbstractInverse eigenvalue problem refers to the problem of reconstructing a matrix of a desired structure from a prescribed eigendata. In this paper, we discuss two additive inverse eigenvalue problems for matrices whose graph is tree. In order to analyze the problems, the vertices of the given tree are labeled in a suitable way so that concrete recurrence relations between the characteristic polynomials of the leading principal submatrices of the matrix can be obtained in a simple form. The method of obtaining the entries of the required matrix is constructive and provides an algorithm for computing the same. We provide some numerical examples to illustrate the results. The computations are done using SCILAB by feeding the eigendata and the adjacency pattern of the tree as inputs
Differentially regulated gene expression in quiescence versus senescence and identification of ARID5A as a quiescence associated marker
No full textIn multicellular organisms majority of the cells remain in a non-dividing states of either quiescence (reversible) or senescence (irreversible). In the present study, gene expression signatures unique to quiescence and senescence were identified using microarray in osteosarcoma cell line, U2OS. It was noted that certain genes and pathways like NOD pathway was shared by both the growth arrest conditions. A major highlight of the present study was increased expression of number of chemokines and cytokines in both quiescence and senescence. While senescence-associated secretory phenotype (SASP) is well known, the quiescence-associated secretory phenotype (QASP) is relatively unknown and appeared novel in this study. ARID5A, a subunit of SWI/SNF complex was identified as a quiescence associated gene. The endogenous expression of ARID5A increased during serum starved condition of quiescence. Overexpression of ARID5A resulted in more number of cells in G0/G1 phase of cell cycle. Further ARID5A overexpressing cells when subjected to serum starvation showed a pronounced secretory phenotype. Overall, the present work has identified gene expression signatures which can distinguish quiescence from senescence
Hepatitis B virus induces cell proliferation via HBx-induced microRNA-21 in hepatocellular carcinoma by targeting programmed cell death protein4 (PDCD4) and phosphatase and tensin homologue (PTEN).
No full textHepatitis B viral infection-induced hepatocellular carcinoma is one of the major problems in the developing countries. One of the HBV proteins, HBx, modulates the host cell machinery via several mechanisms. In this study we hypothesized that HBV enhances cell proliferation via HBx-induced microRNA-21 in hepatocellular carcinoma. HBx gene was over-expressed, and miRNA-21 expression and cell proliferation were measured in Huh 7 and Hep G2 cells. miRNA-21 was over-expressed in these cells, cell proliferation and the target proteins were analyzed. To confirm the role of miRNA-21 in HBx-induced proliferation, Hep G 2.2.1.5 cells (a cell line that expresses HBV stably) were used for miRNA-21 inhibition studies. HBx over-expression enhanced proliferation (3.7- and 4.5-fold increase; n = 3; p<0.01) and miRNA-21 expression (24- and 36-fold increase, normalized with 5S rRNA; p<0.001) in Huh 7 and Hep G2 cells respectively. HBx also resulted in the inhibition of miRNA-21 target proteins, PDCD4 and PTEN. miRNA-21 resulted in a significant increase in proliferation (2- and 2.3-fold increase over control cells; p<0.05 in Huh 7 and Hep G2 cells respectively) and decreased target proteins, PDCD4 and PTEN expression. Anti-miR-21 resulted in a significant decrease in proliferation (p<0.05) and increased miRNA-21 target protein expression. We conclude that HBV infection enhances cell proliferation, at least in part, via HBx-induced miRNA-21 expression during hepatocellular carcinoma progression
Placental expression of asialoglycoprotein receptor associated with Hepatitis B virus transmission from mother to child
No full textProposed Model of HBx-miRNA-21 relationship.
No full text<p>Schematic diagram showing the relationship between HBx, miRNA-21, akt and cellular proliferation in hepatic cells.</p
Effect of HBx in miRNA-21-induced PDCD4 and PTEN in Hep G2 cells.
No full text<p>Hep G2 cells were transfected with anti-miR21, followed by transfection with HBx plasmid. After 48 hours of HBx plasmid transfection, the cells were collected and Western blots for PDCD4 and PTEN were performed. A, shows the protein levels of miRNA-21 target proteins, PDCD4 and PTEN in anti-miR-21 transfected cells. As an internal control β-actin was used in all the Western blot experiments. Lane 1, Control; lane 2, Anti-miR21 and HBx-transfected cells; and lane 3, HBx only transfected cells. B, The Western blots were quantified and the data are presented from three experiments. (*p<0.05, compared with HBx only transfected cell; **p<0.01, compared with control cells).</p
Effect of miRNA-21 on PDCD4 and PTEN proteins in LX2 and Hela Cells.
No full text<p>A, shows a representative picture of Western blot results of miRNA-21 target proteins, PDCD4 and PTEN in miRNA-21 over-expressing LX2 and Hela cells. As an internal control β-actin was used in all the Western blot experiments. Lane 1, Control; lane 2, NS-miRNA transfected cells; and lane 3, miRNA-21 transfected cells. The Western blots were quantified and the data are presented for LX2 (B) and Hela (C) cells (n = 3; *p<0.05).</p
Transfection efficiency in Huh 7 and Hep G2 cells.
No full text<p>Both Huh 7 (A and B) and Hep G2 (C and D) cells were transfected with eGFP-N1 plasmid using the similar transfection conditions as HBx. After 48 hours of transfection, the cells were observed (10× magnification). Both A and C are fluorescent pictures and B and D are corresponding phase-contrast pictures.</p
Effect of miRNA-21 on PDCD4 and PTEN proteins.
No full text<p>A, shows the Western blot results of miRNA-21 target proteins, PDCD4 and PTEN in miRNA-21 over-expressing cells. As an internal control β-actin was used in all the Western blot experiments. This is a representative picture from three experiments. Lane 1, Control; lane 2, NS-miRNA transfected cells; and lane 3, miRNA-21 transfected cells. The Western blots were quantified and the data are presented for Huh 7 (B) and Hep G2 (C) cells (n = 3; *p<0.05).</p
