A note on the biology ofBracon gelechiae [Hym.: Braconidae] and augmentation of this parasite againstPectinophora Gossypiella [Lep.: Gelechiidae]

BioControl - Studies on the biology ofBracon gelechiae Ashm. and augmentation of this parasite againstPectinophora gossypiella (Saund.) were conducted. The development ofB. gelechiae from egg to...     

A Partially Folded State of Ovalbumin at Low pH Tends to Aggregate

At pH 2, ovalbumin retains native-like secondary structure as seen by far-UV CD and FTIR, but lacks well-defined tertiary structure as seen by the fluorescence and near-UV CD spectra. Addition of 20 mM Trifluoroacetic acid (TFA) or 30 mM Trichloroacetic acid (TCA) on acid-induced state results in protein aggregation. This aggregated state possesses extensive β-sheet structure as revealed by far-UV CD and FTIR spectroscopy. Furthermore, the aggregates exhibit decreased ANS fluorescence and increased thioflavin T fluorescence. The presence of aggregates was confirmed by size exclusion chromatography. Such a formation of β-sheet structure is found in the amyloid of a number of neurological diseases such as Alzheimer’s and scrapie. Ovalbumin at low pH, in the presence of K₂SO₄, exists in partially folded state characterized by native-like secondary structure and tertiary folds.     

Substrate analysis of homoserine acyltransferase from Bacillus cereus

Substrate specificity within the family of enzymes designated as homoserine transsuccinylases is variable, with some organisms utilizing succinyl-CoA and other organisms utilizing acetyl-CoA. In this study it is shown that the enzyme from Bacillus cereus uses acetyl-CoA as its acyl donor, but its catalytic rate is significantly lower than other HTS family members. BcHTS is inactivated by both iodoacetamide and diethyl pyrocarbonate and the enzyme can be partially protected from inactivation by the presence of succinyl-CoA. This leads to the conclusion that BcHTS can bind both acetyl-CoA and succinyl-CoA and suggests that it may represent an intermediate between the succinate-transferring HTS family members and the acetate-transferring HTS family members. The B. cereus enzyme was unable to rescue growth of an Escherichia coli strain lacking a functional transsuccinylase, however.     

Acute inhibition of superoxide formation and Rac1 activation by nitric oxide and iloprost in human vascular smooth muscle cells in response to the thromboxane A2 analogue, U46619

BACKGROUND: The over-production of superoxide (O(2)(-)) derived from NADPH oxidase (NOX) plays a central role in cardiovascular diseases. By contrast, nitric oxide (NO) and prostacyclin (PGI(2)) are vasculoprotective. The effect of the NO donor, NONOate and iloprost on O(2)(-) formation, p47(phox) and Rac(1) activation in human vascular smooth muscle cells (hVSMCs) was investigated. METHODS: hVSMCs were incubated with 10nM thromboxane A(2) analogue, U46619 for 16h, and then with apocynin (a NOX inhibitor), NONOate or iloprost for 1h and O(2)(-) measured spectrophometrically. The role of cyclic AMP and cyclic GMP was examined by co-incubation of drugs with protein kinase (PK) A and G inhibitors listed above. Rac(1) was studied using pull-down assays. RESULTS: NONOate and iloprost inhibited O(2)(-) formation, acutely, effects blocked by inhibition of PKG and PKA, respectively. Rac(1) and p47(phox) activation and translocation to the plasma membrane was completely inhibited by NONOate and iloprost, effects again reversed by co-incubation with PKG or PKA inhibitors. CONCLUSIONS: NO and PGI(2) block the acute activity of NOX in hVSMCs via the cGMP-PKG axis (for NO) and by the cAMP-PKA axis (for iloprost) through inhibition of Rac(1) and p47(phox) translocation. These findings have implications in the pathophysiology and treatment of CVD.     

Aberrant promoter methylation and reduced expression of p16 gene in esophageal squamous cell carcinoma from Kashmir valley: a high-risk area

Esophageal squamous cell carcinoma (ESCC) is one of the most prevalent cancer in Jammu and Kashmir region of India and has multi-factorial etiology involving dietary habits, genetic factors, and gene environmental interactions. Inactivation of the p16 gene expression by aberrant promoter methylation plays an important role in the progression of esophageal carcinoma. In the present investigation, we have studied the role of p16 promoter methylation in 69 histopathologically confirmed ESCC tissues and compared it with corresponding normal adjacent tissues for DNA methylation in the CpG island in the p16 promoter region by methylation-specific polymerase chain reaction (MSP) and p16 protein expression by immunoblotting. The results showed loss of p16 expression in 67% (46/69) of tumor tissues compared to only 3% in control tissues (2/69). Promoter methylation was observed in 52% (36/69) of tumor tissues and it gradually increased with the increasing severity of histological grades of the cancer (P = 0.0001). Loss of p16 expression with promoter methylation was observed in 26 of 36 cases (72%). Analysis of patients dietary habits revealed a strong association between promoter methylation and high consumption of hot salted tea (P < 0.05) which is a most favourite drink commonly consumed by Kashmiri people.     

A spectroscopic and molecular dynamic approach on the interaction between ionic liquid type gemini surfactant and human serum albumin

The interactions of imidazolium bashed ionic liquid-type cationic gemini surfactant ([C₁₂-4-C₁₂im]Br₂) with HSA were studied by fluorescence, time-resolved fluorescence, UV-visible, circular dichroism, molecular docking and molecular dynamic simulation methods. The results showed that the [C₁₂-4-C₁₂im]Br₂ quenched the fluorescence of HSA through dynamic quenching mechanism as confirmed by time-resolved spectroscopy. The Stern–Volmer quenching constant (K_sv) and relevant thermodynamic parameters such as enthalpy change (ΔH), Gibbs free energy change (ΔG) and entropy change (ΔS) for interaction system were calculated at different temperatures. The results revealed that hydrophobic forces played a major role in the interactions process. The results of synchronous fluorescence, UV-visible and CD spectra demonstrated that the binding of [C₁₂-4-C₁₂im]Br₂ with HSA induces conformational changes in HSA. Inquisitively, the molecular dynamics study contribute towards understanding the effect of binding of [C₁₂-4-C₁₂im]Br₂ on HSA to interpret the conformational change in HSA upon binding in aqueous solution. Moreover, the molecular modelling results show the possible binding sites in the interaction system.     

Solution Structure of the QUA1 Dimerization Domain of pXqua,the Xenopus Ortholog of Quaking

The STAR protein family member Quaking is essential for early development in vertebrates. For example, in oligodendrocyte cells it regulates the splicing, localization, translation and lifetime of a set of mRNAs that code for crucial components of myelin. The Quaking protein contains three contiguous conserved regions: a QUA1 oligomerization element, followed by a single-stranded RNA binding motif comprising the KH and QUA2 domains. An embryonic lethal point mutation in the QUA1 domain, E48G, is known to affect both the aggregation state and RNA-binding properties of the murine Quaking ortholog (QKI). Here we report the NMR solution structure of the QUA1 domain from the Xenopus laevis Quaking ortholog (pXqua), which forms a dimer composed of two perpendicularly docked α-helical hairpin motifs. Size exclusion chromatography studies of a range of mutants demonstrate that the dimeric state of the pXqua QUA1 domain is stabilized by a network of interactions between side-chains, with significant roles played by an intra-molecular hydrogen bond between Y41 and E72 (the counterpart to QKI E48) and an inter-protomer salt bridge between E72 and R67. These results are compared with recent structural and mutagenesis studies of QUA1 domains from the STAR family members QKI, GLD-1 and Sam68.     

Characterizing pathogenic processes in Batten disease: use of small eukaryotic model systems

The neuronal ceroid lipofuscinoses (NCLs) are neurodegenerative disorders. Nevertheless, small model organisms, including those lacking a nervous system, have proven invaluable in the study of mechanisms that underlie the disease and in studying the functions of the conserved proteins associated to each disease. From the single-celled yeast, Saccharomyces cerevisiae and Schizosaccharomyces pombe, to the worm, Caenorhabditis elegans and the fruitfly, Drosophila melanogaster, biochemical and, in particular, genetic studies on these organisms have provided insight into the NCLs.     

Diversity in Phytochemical Composition and Medicinal Value of Murraya paniculata

Murraya paniculata is herbal medicinal plant which is traditionally being used for management of cardiovascular, intestinal and respiratory (air way) disorders. This evergreen plant of tropical regions is a member of Rutaceace family. The goal of this review is to analyze and report the biological activities and active phytochemicals reported from Murraya paniculata (M. paniculata) extracts and essential oil. The data was searched using different search engines and using specific key words including M. paniculata, herbal medicine, phytochemicals, extract, essential oil, pharmacological activities. M. paniculata has been found to have wide range of pharmacological activities, including antinociceptive, antianxiety, antioxidant, antidepressant, antibacterial, analgesic and anti-diabetic properties. A diverse range of phytochemicals, including phenols, coumarins, terpenoids, flavonoids, and alkaloids have been isolated from various portions of the plant and tested for a variety of biological activities. This review will provide more information and stimulate additional research to develop more effective and cost-efficient alternative medicine from this plant.