Effect of concentration and temperature variations on interactions in (L-serine/L-valine + aqueous glucose/sucrose/lactose) systems: Viscometric and activation parametric study

Viscosities of (L-serine/L-valine + 0.1 mol dm-3 aqueous glucose/sucrose/lactose) systems have been measured as a function of molal concentration of amino acids at different temperatures; 293.15 K, 298.15 K, 303.15 K, 308.15 K and 313.15 K. The viscosity data has been utilized to determine viscosity B-coefficients employing Jones-Dole equation. The viscosity B-coefficients of transfer (ΔtrB), variation of B with temperature (dB/dT) and solvation number (Sn) of L-serine/L-valine have been obtained using the experimental viscosity values. Further, Gibbs free energy of activation of viscous flow per mole of solvent (Δµ°) as well as per mole of solute (Δµ°) along with activation enthalpy (ΔH°) and entropy (ΔS°) have been computed using Feakin’s transition state theory to throw light on the mechanism of viscous flow. The results have been discussed in terms of solute-solvent interactions; and structure making tendency of amino acid molecules in aqueous saccharides solutions

Analysis of detergent-free lipid rafts isolated from CD4+ T cell line: interaction with antigen presenting cells promotes coalescing of lipid rafts

<p>Abstract</p> <p>Background</p> <p>Lipid rafts present on the plasma membrane play an important role in spatiotemporal regulation of cell signaling. Physical and chemical characterization of lipid raft size and assessment of their composition before, and after cell stimulation will aid in developing a clear understanding of their regulatory role in cell signaling. We have used visual and biochemical methods and approaches for examining individual and lipid raft sub-populations isolated from a mouse CD4⁺T cell line in the absence of detergents.</p> <p>Results</p> <p>Detergent-free rafts were analyzed before and after their interaction with antigen presenting cells. We provide evidence that the average diameter of lipid rafts isolated from un-stimulated T cells, in the absence of detergents, is less than 100 nm. Lipid rafts on CD4⁺T cell membranes coalesce to form larger structures, after interacting with antigen presenting cells even in the absence of a foreign antigen.</p> <p>Conclusions</p> <p>Findings presented here indicate that lipid raft coalescence occurs during cellular interactions prior to sensing a foreign antigen.</p

Densimetric, acoustic and viscometric behaviour of sucrose solutions in aqueous 1-butyl-3-methylimidazolium hexafluorophosphate at different temperatures and ambient pressure

31-42The thermophysical properties like density, speed of sound and viscosity have been measured for different molalities of sucrose in aqueous and different concentrations of aqueous solutions of an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, at different temperatures and atmospheric pressure. The results are explained in terms of acoustic parameters like apparent molar volume, apparent molar isentropic compressibility, limiting apparent molar volume, limiting apparent molar isentropic compressibility, limiting apparent molar transfer volume, limiting apparent molar transfer compressibility, hydration number, etc. Further, pair and triplet interaction coefficients, solvation number, viscosity B-coefficients and activation parameters have also been evaluated. The results demonstrate that solute-solvent interactions exist in the ternary system which increases with an increase in ionic liquid concentration

Downregulated Expression of Ly-6-ThB on Developing T Cells Marks CD4+CD8+ Subset Undergoing Selection in the Thymus

Interaction of TCRs on CD4+CD8+ immature T cell with MHC-peptide complexes on stromal cells is required for positive and negative selection in the thymus. Identification and characterization of a subpopulation of CD4+CD8+ thymocytes undergoing selection in the thymus will aid in understanding the mechanisms underlying lineage commitment and thymic selection. Herein, we describe the expression of Ly-6 ThB on developing thymocytes. The majority of CD4+CD8+ thymocytes express Ly-6 ThB at high levels. Its expression is downregulated in a subset of CD4+CD8+ thymocytes as well as in mature CD4+CD8- and CD4-CD8+ T cells. More importantly, interaction of TCR/coreceptor with the self-MHC-peptide contributes to the downregulation of ThB expression on developing thymocytes. These findings indicate that downregulation of ThB on CD4+CD8+ thymocytes identifies a unique subset (CD4+CD8+ThBneg–low) of thymocytes that has received the initial signals for thymic selection but have not yet downregulated the CD4 and CD8 cell surface expression. In addition, these results also indicate that a high frequency (Ÿ20–40%) of CD4+CD8+ immature thymocytes receive these initial signals during thymic selection

Diversity of antigenic determinants of porcine zona pellucida revealed by monoclonal antibodies

Monoclonal antibodies derived from ten hybrid cell clones, generated against porcine zona pellucida gave strong immunofluorescence with zona but the pattern varied from patchy, thin rim to heavy precipitation type of rim. Five of the 6 monoclonals studied prevented the binding of the porcine epididymal sperm to homologous oocytesin vitro, whereas the sixth one was partially effective. All of the 6 monoclonale of this batch inhibited the lysis of zonae by proteolytic enzymes even at dilutions up to 1×10−3. Three of the four monoclonals prepared in a subsequent batch gave strong immunofluorescent reactions and had high titres as determined by enzyme immunoassay. These monoclonals did not, however, protect the zonae against lysis by proteolytic enzymes. These properties are suggestive of the heterogeneity of the antigenic determinants in zona and emphasize the employment of appropriate bioassays for screening and selection of bioeffective antibodies

Investigation of DNA damage response and apoptotic gene methylation pattern in sporadic breast tumors using high throughput quantitative DNA methylation analysis technology

<p>Abstract</p> <p>Background-</p> <p>Sporadic breast cancer like many other cancers is proposed to be a manifestation of abnormal genetic and epigenetic changes. For the past decade our laboratory has identified genes involved in DNA damage response (DDR), apoptosis and immunesurvelliance pathways to influence sporadic breast cancer risk in north Indian population. Further to enhance our knowledge at the epigenetic level, we performed DNA methylation study involving 17 gene promoter regions belonging to DNA damage response (DDR) and death receptor apoptotic pathway in 162 paired normal and cancerous breast tissues from 81 sporadic breast cancer patients, using a high throughput quantitative DNA methylation analysis technology.</p> <p>Results-</p> <p>The study identified five genes with statistically significant difference between normal and tumor tissues. Hypermethylation of <it>DR5 </it>(P = 0.001)<it>, DCR1 </it>(P = 0.00001)<it>, DCR2 </it>(P = 0.0000000005) and <it>BRCA2 </it>(P = 0.007) and hypomethylation of <it>DR4 </it>(P = 0.011) in sporadic breast tumor tissues suggested a weak/aberrant activation of the DDR/apoptotic pathway in breast tumorigenesis. Negative correlation was observed between methylation status and transcript expression levels for <it>TRAIL</it>, <it>DR4</it>, <it>CASP8</it>, <it>ATM</it>, <it>CHEK2</it>, <it>BRCA1 </it>and <it>BRCA2 </it>CpG sites. Categorization of the gene methylation with respect to the clinicopathological parameters showed an increase in aberrant methylation pattern in advanced tumors. These uncharacteristic methylation patterns corresponded with decreased death receptor apoptosis (P = 0.047) and DNA damage repair potential (P = 0.004) in advanced tumors. The observation of BRCA2 -26 G/A 5'UTR polymorphism concomitant with the presence of methylation in the promoter region was novel and emerged as a strong candidate for susceptibility to sporadic breast tumors.</p> <p>Conclusion-</p> <p>Our study indicates that methylation of DDR-apoptotic gene promoters in sporadic breast cancer is not a random phenomenon. Progressive epigenetic alterations in advancing tumors result in aberrant DDR-apoptotic pathway thereby promoting tumor development. We propose, since pathological epigenetic changes of the DDR-apoptotic genes are reversible modifications, these could further be targeted for therapeutic interventions.</p

H2AFX (H2A histone family, member X)

Review on H2AFX (H2A histone family, member X), with data on DNA, on the protein encoded, and where the gene is implicated

Densimetric, acoustic and viscometric behaviour of sucrose solutions in aqueous 1-butyl-3-methylimidazolium hexafluorophosphate at different temperatures and ambient pressure

The thermophysical properties like density, speed of sound and viscosity have been measured for different molalities of sucrose in aqueous and different concentrations of aqueous solutions of an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, at different temperatures and atmospheric pressure. The results are explained in terms of acoustic parameters like apparent molar volume, apparent molar isentropic compressibility, limiting apparent molar volume, limiting apparent molar isentropic compressibility, limiting apparent molar transfer volume, limiting apparent molar transfer compressibility, hydration number, etc. Further, pair and triplet interaction coefficients, solvation number, viscosity B-coefficients and activation parameters have also been evaluated. The results demonstrate that solute-solvent interactions exist in the ternary system which increases with an increase in ionic liquid concentration