Studies on the interaction of the food colorant tartrazine with double stranded deoxyribonucleic acid

Interaction of the food additive tartrazine with double-stranded DNA was studied by spectroscopic and calorimetric techniques. Absorbance studies revealed that tartrazine exhibited hypochromism in the presence of DNA without any bathochromic effects. Minor groove displacement assay of DAPI and Hoechst 33258 suggested that tartrazine binds in the minor groove of DNA. The complexation was predominantly entropy driven with a smaller but favorable enthalpic contribution to the standard molar Gibbs energy. The equilibrium constant was evaluated to be (3.68?±?.08)?×?10⁴?M^?1 at 298.15?K. The negative standard molar heat capacity value along with an enthalpy–entropy compensation phenomenon proposed the involvement of dominant hydrophobic forces in the binding process. Tartrazine enhanced the thermal stability of DNA by 7.53?K under saturation conditions.     

The Des-1 protein, required for central spindle assembly and cytokinesis, is associated with mitochondria along the meiotic spindle apparatus and with the contractile ring during male meiosis in Drosophila melanogaster

Spermatogenesis in Drosophila melanogaster serves as an excellent model system for the isolation and analysis of genes required in the control of chromosome segregation and cytokinesis. We report here the isolation and molecular characterization of a novel P-element induced allele of the des-1 gene, which leads to male sterility as a consequence of the failure of central spindle assembly in meiotic spermatocytes and the formation of aberrant meiotic end products characteristic of cytokinesis failure. We have raised affinity-purified antibodies against a Des-1 fusion protein, and localized the Des-1 protein in Drosophila spermatocytes. We show that the Des-1 protein is colocalized with mitochondria throughout male meiosis, becoming intimately associated with mitochondria along the spindle apparatus during anaphase and telophase, and with the Nebenkern, or mitochondrial derivative, of the meiotic end products. In addition, a significant association of Des-1 with the contractile ring is observed during anaphase and telophase of meiosis. These observations, together with the presence of six potential transmembrane domains in the Des-1 protein, raise the possibility that Des-1 may act as part of an anchoring mechanism that links membrane-bounded cellular compartments to components of the cytoskeleton.     

Identification of QTLs for Yield and Associated Traits in F₂ Population of Rice

Identification of quantitative trait loci (QTLs) controlling yield and yield-related traits in rice was performed in the F₂ mapping population derived from parental rice genotypes DHMAS and K343. A total of 30 QTLs governing nine different traits were identified using the composite interval mapping (CIM) method. Four QTLs were mapped for number of tillers per plant on chromosomes 1 (2 QTLs), 2 and 3; three QTLs for panicle number per plant on chromosomes 1 (2 QTLs) and 3; four QTLs for plant height on chromosomes 2, 4, 5 and 6; one QTL for spikelet density on chromosome 5; four QTLs for spikelet fertility percentage (SFP) on chromosomes 2, 3 and 5 (2 QTLs); two QTLs for grain length on chromosomes 1 and 8; three QTLs for grain width on chromosomes1, 3 and 8; three QTLs for 1000-grain weight (TGW) on chromosomes 1, 4 and 8 and six QTLs for yield per plant (YPP) on chromosomes 2 (3 QTLs), 4, 6 and 8. Most of the QTLs were detected on chromosome 2, so further studies on chromosome 2 could help unlock some new chapters of QTL for this cross of rice variety. Identified QTLs elucidating high phenotypic variance can be used for marker-assisted selection (MAS) breeding. Further, the exploitation of information regarding molecular markers tightly linked to QTLs governing these traits will facilitate future crop improvement strategies in rice.     

Heregulin-induced epigenetic regulation of the utrophin-A promoter

Utrophin is the autosomal homolog of dystrophin, the product of the Duchenne's muscular dystrophy (DMD) locus. Utrophin is of therapeutic interest since its over-expression can compensate dystrophin's absence. Utrophin is enriched at neuromuscular junctions due to heregulin-mediated utrophin-A promoter activation. We demonstrate that heregulin activated MSK1/2 and phosphorylated histone H3 at serine 10 in cultured C2C12 muscle cells, in an ERK-dependent manner. MSK1/2 inhibition suppressed heregulin-mediated utrophin-A activation. MSK1 over-expression potentiated heregulin-mediated utrophin-A activation and chromatin remodeling at the utrophin-A promoter. These results identify MSK1/2 as key effectors modulating utrophin-A expression as well as identify novel targets for DMD therapy.     

Multivalent Role of Human TFIID in Recruiting Elongation Components at the Promoter-Proximal Region for Transcriptional Control

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Maternal footprints of Southeast Asians in North India

We have analyzed 7,137 samples from 125 different caste, tribal and religious groups of India and 99 samples from three populations of Nepal for the length variation in the COII/tRNA(Lys) region of mtDNA. Samples showing length variation were subjected to detailed phylogenetic analysis based on HVS-I and informative coding region sequence variation. The overall frequencies of the 9-bp deletion and insertion variants in South Asia were 1.9 and 0.6%, respectively. We have also defined a novel deep-rooting haplogroup M43 and identified the rare haplogroup H14 in Indian populations carrying the 9-bp deletion by complete mtDNA sequencing. Moreover, we redefined haplogroup M6 and dissected it into two well-defined subclades. The presence of haplogroups F1 and B5a in Uttar Pradesh suggests minor maternal contribution from Southeast Asia to Northern India. The occurrence of haplogroup F1 in the Nepalese sample implies that Nepal might have served as a bridge for the flow of eastern lineages to India. The presence of R6 in the Nepalese, on the other hand, suggests that the gene flow between India and Nepal has been reciprocal.     

F2-isoprostane, inflammation, cardiac function and oxygenation in the endotoxaemic pig

Prostaglandins are profoundly involved in endotoxaemic shock. Twenty pigs were given endotoxin at various doses (0.063-16 microg kg(-1) h(-1)). Three non-endotoxaemic pigs served as controls. Two eicosanoids were measured in plasma (8-iso-PGF(2alpha), a free radical-mediated lipid peroxidation product, and 15-keto-dihydro-PGF(2alpha) a major metabolite of COX activity) and evaluated against the pathophysiological responses that occur during endotoxaemic shock. Endotoxin mediates an increase in both 8-iso-PGF(2alpha) and 15-keto-dihydro-PGF(2alpha). An increase in the endotoxin dose induced significant log-linear responses in 8-iso-PGF(2alpha) and 15-keto-dihydro-PGF(2alpha). Oxidative injury correlated to the TNF-alpha, IL-6, reductions in cardiac performance and to oxygen delivery and utilisation. COX-mediated inflammatory responses correlated to TNF-alpha, IL-6 and to reductions in arterial oxygen tension. Thus, oxidative injury and COX-mediated inflammation play a central role in the manifestation of endotoxaemic shock. Furthermore, formation of these eicosanoids on endotoxin-mediated alterations in pulmonary hypertension, oxygen delivery and oxygen utilisation seems to be independent of the administered endotoxin dose.     

A comparative study on the interaction of the putative anticancer alkaloids,sanguinarine and chelerythrine,with single- and double-stranded,and heat-denatured DNAs

A detailed investigation on the interaction of two benzophenanthridine alkaloids, sanguinarine (SGR) and chelerythrine (CHL), with the double-stranded (ds), heat-denatured (hd), and single-stranded (ss) DNA was performed by spectroscopy and calorimetry techniques. Binding to the three DNA conformations leads to quenching of fluorescence of SGR and enhancement in the fluorescence of CHL. The binding was cooperative for both of the alkaloids with all the three DNA conformations. The binding constant values of both alkaloids with the ds DNA were in the order of 10⁶ M^?1; binding was weak with hd and much weaker to the ss DNA. The fluorescence emission of the alkaloid molecules bound to the ds and hd DNAs was quenched much less compared to those bound to the ss DNA based on competition with the anionic quencher KI. For both double stranded and heat denatured structures the emission of the bound alkaloid molecules was polarized significantly and strong energy transfer from the DNA bases to the alkaloid molecules occurred. Intercalation of SGR and CHL to ds, hd, and ss DNA was proved from these fluorescence results. Calorimetric studies suggested that the binding to all DNA conformations was both enthalpy and entropy favored. Both the alkaloids preferred double-helical regions for binding, but SGR was a stronger binder than CHL to all the three DNA structures.     

Biomarkers of free radical injury during spinal cord ischemia.

Plasma and urinary levels of 8-iso-PGF(2alpha) and 15-keto-dihydro-PGF(2alpha) were analysed at baseline and during the ischemia-reperfusion period in experimental spinal cord ischemia. A significant and immediate increase of 8-iso-PGF(2alpha) in plasma at the start and up to 60 min, and in the urine at 90-150 min following ischemia indicate an association of oxidative injury. The inflammatory response indicator 15-keto-dihydro-PGF(2alpha) in plasma increased significantly at the start and up to 60 min after ischemia. No such increase was seen in animals with no spinal cord ischemia. Thus, free radical mediated and cyclooxygenase catalysed products of arachidonic acid are increased during spinal cord ischemia as a consequence of oxidative injury and inflammation.