Sclerotial development, melanin production and lipid peroxidation bySclerotium rolfsii

Melanin pigments constituted 13.9% (W/W) of sclerotial walls ofSclerotium rolfsii. The lipid and ash contents in sclerotial walls were twice those in hyphal walls of the fungus. Progress in culture age and maturation of sclerotia were always accompanied by increased levels of lipid peroxidation products and melanin. Lipid peroxidation and melanin formation may thus proceed in parallel during sclerotial biogenesis and maturation. Both these processes are strongly affected by Fe²⁺ and by antioxidant vitamins (ascorbic acid), microelements (selenium) and mercapto compounds (glutathione). Myceliogenic germination and lytic activityvia melanin production can thus be affected by (anti)oxidants that could potentially be used for controlling sclerotia-producing fungi without using traditional toxic fungicides.     

Micellar-emphasized simultaneous determination of ivabradine hydrochloride and felodipine using synchronous spectrofluorimetry

A sensitive and green micellar spectrofluorimetric approach was applied for the simultaneous estimation of ivabradine hydrochloride (IVB) and felodipine (FLD) in the ng/ml concentration range. The approach depended on measuring the first derivative synchronous peak amplitude (¹D) of both drugs at ∆λ = 60 nm in a Tween-80 micellar system. The method was rectilinear alongside the concentration ranges 0.02–0.4 μg/ml and 0.05–1.0 μg/ml at 269.5 nm and 378.5 nm for IVB and FLD, respectively. The proposed method was validated by following the International Council for Harmonization guidelines. The method was successfully applied without interference for laboratory-prepared synthetic mixtures, single pharmaceutical preparations, and within spiked biological fluids with acceptable percentage recoveries. A comparison of the performance of the suggested method with other methods, showed no discrepancy. The method’s ecofriendly property evaluated using three different tools, confirming an excellent green method.     

Cell surface ceramide controls translocation of transferrin receptor to clathrin-coated pits

Transferrin receptor mediates internalization of transferrin with bound ferric ions through the clathrin-dependent pathway. We found that binding of transferrin to the receptor induced rapid generation of cell surface ceramide which correlated with activation of acid, but not neutral, sphingomyelinase. At the onset of transferrin internalization both ceramide level and acid sphingomyelinase activity returned to their basic levels. Down-regulation of acid sphingomyelinase in cells with imipramine or silencing of the enzyme expression with siRNA stimulated transferrin internalization and inhibited its recycling. In these conditions colocalization of transferrin with clathrin was markedly reduced. Simultaneously, K⁺ depletion of cells which interfered with the assembly of clathrin-coated pits inhibited the uptake of transferrin much less efficiently than it did in control conditions. The down-regulation of acid sphingomyelinase activity led to the translocation of transferrin receptor to the raft fraction of the plasma membrane upon transferrin binding. The data suggest that lack of cell surface ceramide, generated in physiological conditions by acid sphingomyelinase during transferrin binding, enables internalization of transferrin/transferrin receptor complex by clathrin-independent pathway.     

Augmentation of innate immunity by low-dose irradiation

The effect of low-dose irradiation on the immune system was investigated in mice. When a 0.2 Gy dose of X-ray irradiation was administered every other day for a total of four times, the number of lymphocytes yielded by the liver, spleen and thymus decreased at the initial stage (around day 10). At this stage, NK cells, extrathymic T cells and NKT cells were found to be radioresistant. In other words, conventional lymphocytes were radiosensitive, even in the case of low-dose irradiation. However, the number of lymphocytes in all tested immune organs increased beyond the control level at the recovery stage (around day 28). Enumeration of the absolute number of lymphocyte subsets showed that the most prominently expanding populations were NK cells, extrathymic T cells and NKT cells, especially in the liver where primordial lymphocytes are primarily present. Functional and phenotypic activation of these populations also occurred at the recovery stage. It raised a possibility that an initial activation of macrophages by low-dose irradiation then mediated the present phenomenon. These results suggest that low-dose irradiation eventually has the potential to induce a hormesis effect on the immune system.     

Analysis of serotonin receptor 2A gene (HTR2A): Association study with autism spectrum disorder in the Indian population and investigation of the gene expression in peripheral blood leukocytes

Several studies suggest involvement of serotoninergic system in the pathophysiology of Autism Spectrum Disorder (ASD). The 5-HT receptor binding studies using ³H-lysergic acid diethylamide (³H-LSD) and linkage analysis provided evidences to consider HTR2A as a potential candidate gene for ASD. The three SNPs, −1438A/G (rs6311), 102T/C (rs6313) and 1354C/T (rs6314) of HTR2A have been well studied in the etiology of various neuropsychiatric disorders. But studies on association of this gene with ASD are limited to two reports from American and Korean populations. Additionally there are reports, which demonstrated paternal imprinting of HTR2A with expression from only one allele. So far no reports are available on HTR2A and its association with any neuropsychiatric disorders from Indian population. Therefore, the present study investigates association of the above mentioned three markers of HTR2A with ASD in Indian population using population and family-based approaches. The study also deals with allelic expression pattern of HTR2A in Peripheral Blood Leukocytes (PBLs) to understand the parental imprinting status. The genotyping analyses were carried out for probands, parents and controls. The subsequent association analyses did not show association of these markers with ASD. So, HTR2A is unlikely to be a genetic marker for ASD in Indian population. The expression analyses showed absence of monoallelic expression, suggesting lack of parental imprinting of HTR2A gene. However, we noticed methylation of the CpG sites at −1438A/G and 102T/C loci of HTR2A gene. Further bioinformatics analysis revealed absence of CpG islands in the promoter of the gene supporting biallelic expression pattern of HTR2A in PBLs.     

The First Propeller Domain of LRP6 Regulates Sensitivity to DKK1

The Wnt coreceptor LRP6 is required for canonical Wnt signaling. To understand the molecular regulation of LRP6 function, we generated a series of monoclonal antibodies against the extra cellular domain (ECD) of LRP6 and selected a high-affinity mAb (mAb135) that recognizes cell surface expression of endogenous LRP6. mAb135 enhanced Wnt dependent TCF reporter activation and antagonized DKK1 dependent inhibition of Wnt3A signaling, suggesting a role in modulation of LRP6 function. Detailed analysis of LRP6 domain mutants identified Ser 243 in the first propeller domain of LRP6 as a critical residue for mAb135 binding, implicating this domain in regulating the sensitivity of LRP6 to DKK1. In agreement with this notion, mAb135 directly disrupted the interaction of DKK1 with recombinant ECD LRP6 and a truncated form of the LRP6 ECD containing only repeats 1 and 2. Finally, we found that mAb135 completely protected LRP6 from DKK1 dependent internalization. Together, these results identify the first propeller domain as a novel regulatory domain for DKK1 binding to LRP6 and show that mAb against the first propeller domain of LRP6 can be used to modulate this interaction.     

Synthesis and biological evaluation of new cytotoxic azanaphthoquinone pyrrolo-annelated derivatives

A series of azanaphthoquinone pyrrolo-annelated derivatives attached to basic side chains have been synthesized. The antiproliferative activities of all compounds were evaluated on at least four different cell lines. The effects on cell cycle and intercalation were investigated.