Calreticulin transacetylase mediated upregulation of thioredoxin by 7,8-diacetoxy-4-methylcoumarin enhances the antioxidant potential and the expression of vascular endothelial growth factor in peripheral blood mononuclear cells

Extensive research carried out in our group on polyphenolic acetates (PAs) substantiated the potential role of PAs in causing diverse biological and pharmacological actions. Our earlier investigations firmly established the calreticulin transacetylase (CRTAase) catalyzed activation of nitric oxide synthase (NOS) by PAs. In this report, we have studied the effect of 7,8-diacetoxy-4-methylcoumarin (DAMC, a model PA) and other acetoxy coumarins on the thioredoxin and VEGF expression in human peripheral blood mononuclear cells (PBMCs), with a view to substantiate our earlier observation that DAMC was a superb inducer of angiogenesis. Real time RT-PCR analysis revealed the enhanced expression of thioredoxin reductase (TRXR) and diminished expression of thioredoxin interacting protein (TRXIP) leading to the increased expression and activity of thioredoxin (TRX) in PBMCs due to the the action of DAMC. The fact that TRX activity of PBMCs was enhanced by various acetoxy coumarins in tune with their affinity to CRTAase as substrate, suggested the possible activation of TRX due to acetylation. The overexpression of thioredoxin was found to correlate with that of VEGF as proved by real time RT-PCR and VEGF -ELISA results, apart from the DAMC-caused enhanced production of NO acting as an inducer of VEGF. Moreover, the intracellular ROS levels were also found to be reduced drastically, by DAMC thus reducing the oxidative stress in cells. These observations strongly evidenced the crucial role of TRX in DAMC-induced tissue angiogenesis with the involvement of VEGF.     

In vitro propagation, genetic and secondary metabolite analysis of Aconitum violaceum Jacq.: a threatened medicinal herb

Aconitum violaceum Jacq. is an important medicinal species used for various health ailments including renal pain, rheumatism and high fever. In the present report, a reproducible in vitro regeneration system for Aconitum violaceum Jacq. has developed from the nodal segment of the plant. Induction of shoot buds was achieved on basal Murashige and Skoog (MS) medium. The shoots were elongated on MS medium supplemented with 0.5 μM 6-benzylaminopurine (BAP) and 0.1 μM α-napthaleneacetic acid (NAA) and subsequently transferred to rooting medium. In vitro grown microshoots of A. violaceum were encapsulated in the alginate beads. The success rate of their re-growth was found to be approximately 85.43 %. Of the encapsulated microshoots, 39.86 % exhibited formation of multiple shoots following re-growth on plant growth regulator free MS medium. Healthy root formation was observed in all microshoots following 2 weeks of transfer on half-strength MS medium containing 0.1 μM indole-3-acetic acid (IAA) and 1.0 μM α-naphthalene acetic acid (NAA). These plants were subsequently transferred to pots containing a mixture of soil, sand and compost (1:1:1 v/v), and same were then shifted in the greenhouse with 87 % survival rate. The molecular analysis was carried out using 35 random amplified polymorphic DNAs (RAPD) primers and 25 inter simple sequence repeats (ISSR) primers. Cluster analysis of the RAPD and ISSR profile revealed an average similarity coefficient of 0.966 and 0.974, respectively, confirming genetic stability of tissue culture-raised (TR) plants and synthetic seed-derived plants (SR). The phytochemical analysis of tissue culture-raised and synthetic seeds-derived plants showed higher aconitine content than control plant. The propagation protocol developed in this study provides a basis for germplasm conservation and harnessing the medicinally active compounds of A. violaceum.     

New national and regional bryophyte records, 47

Abstract

The moss Timmia megapolitana is reported new to the British Isles. It occurs in an area of freshwater tidal Salix carr in the Norfolk Broads and differs from the other two species of Timmia in Britain and Ireland in leaf form and anatomy, sexuality and habitat. In the field Timmia megapolitana is most likely to be passed over as Atrichum undulatum, and since access to the area is difficult there is the possibility that it has been present for many years. The habitat and ecology shows a remarkable similarity to that in the Netherlands, the nearest European locality. Rare in Europe, the plant also occurs in Finland, northern Russia and Siberia, regions that provide staging posts and breeding grounds for migratory birds that over-winter in Norfolk.     

Synthesis and antioxidant activity of thymol and carvacrol based Schiff bases

Thymol and carvacrol are well known antioxidants found in the extract of the plants of thyme species. The Schiff bases of 2-iso-propyl-5-methyl-phenol (thymol/1a), 2-tert-butyl-5-methyl-phenol (1b) and 5-iso-propyl-2-methyl-phenol (carvacrol/1c) exhibited much better antioxidant activity than thymol and carvacrol in DPPH assay. Ten compounds (4k, 4l, 4r, 5k, 5l, 5q, 5r, 6k, 6l and 6r) showed better or similar activity as compared to the reference compound ascorbic acid. Twenty-four most active compounds were also screened by ABTS method and showed 60–90% inhibition at 5 μg/mL concentration.     

Alleviation of the adverse effects of salinity stress in wheat (Triticum aestivum L.) by seed biopriming with salinity tolerant isolates of Trichoderma harzianum

Use of an in-season measure of crop N sufficiency to guide fertilizer management is one approach to match the supply of N to the crop N demand. This study examined use of gene expression in leaf tissue of field-grown potatoes for use in assessment of potato N sufficiency. Potato cultivar ‘Shepody’ was grown with six fertilizer N rates (0–250 kg N ha^–1). Leaf disks were collected weekly for quantification of the expression of N uptake/transport, N assimilation, and amino acid metabolism genes in leaf tissue by nCounter. Many of the genes evaluated were responsive to crop N supply, but the response varied widely among sampling dates. The exception was an ammonium transporter gene (AT1) which was highly expressed, was relatively consistent across sampling dates, was closely related to root zone soil nitrate concentration across N rates and sampling dates, and was highly negatively correlated with total tuber yield. The level of expression of AT1 in leaf tissue was as good as or better than conventional chemical or optical measures of potato N sufficiency in the current study.     

Iodine-catalyzed one-pot synthesis and antimalarial activity evaluation of symmetrically and asymmetrically substituted 3,6-diphenyl[1,2,4,5]tetraoxanes

A novel iodine-catalyzed one-pot synthesis of symmetrically and asymmetrically substituted 3,6-diphenyl-[1,2,4,5]tetraoxanes is described. The synthetic protocol is general with substituted benzaldehydes and proceeds well under acidic conditions. Total 17 tetraoxanes have been prepared during this study and some of these compounds exhibit promising antimalarial activity. None of the compounds shows any toxicity against vero cells.     

Role of tryptophan residues in gramicidin channel organization and function

The linear peptide gramicidin forms prototypical ion channels specific for monovalent cations and has been used extensively to study the organization, dynamics, and function of membrane-spanning channels. The tryptophan residues in gramicidin channels are crucial for maintaining the structure and function of the channel. We explored the structural basis for the reduction in channel conductance in the case of single-tryptophan analogs of gramicidin with three Trp → hydrophobic substitutions using a combination of fluorescence approaches, which include red edge excitation shift and membrane penetration depth analysis, size-exclusion chromatography, and circular dichroism spectroscopy. We show here that the gramicidin analogs containing single-tryptophan residues adopt a mixture of nonchannel and channel conformations, as evident from analysis of membrane penetration depth, size-exclusion chromatography, and backbone circular dichroism data. These results are potentially useful in analyzing the effect of tryptophan substitution on the functioning of other ion channels and membrane proteins.