Vanadium in Biosphere and Its Role in Biological Processes

Ultra-trace elements or occasionally beneficial elements (OBE) are the new categories of minerals including vanadium (V). The importance of V is attributed due to its multifaceted biological roles, i.e., glucose and lipid metabolism as an insulin-mimetic, antilipemic and a potent stress alleviating agent in diabetes when vanadium is administered at lower doses. It competes with iron for transferrin (binding site for transportation) and with lactoferrin as it is secreted in milk also. The intracellular enzyme protein tyrosine phosphatase, causing the dephosphorylation at beta subunit of the insulin receptor, is inhibited by vanadium, thus facilitating the uptake of glucose inside the cell but only in the presence of insulin. Vanadium could be useful as a potential immune-stimulating agent and also as an antiinflammatory therapeutic metallodrug targeting various diseases. Physiological state and dose of vanadium compounds hold importance in causing toxicity also. Research has been carried out mostly on laboratory animals but evidence for vanadium importance as a therapeutic agent are available in humans and large animals also. This review examines the potential biochemical and molecular role, possible kinetics and distribution, essentiality, immunity, and toxicity-related study of vanadium in a biological system.     

A modified HPLC technique for simultaneous measurement of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid in cerebrospinal fluid, platelet and plasma.

A sensitive, reliable and simplified HPLC assay for simultaneous measurement of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in human cerebrospinal fluid (CSF), platelets and plasma is described. Perchloric acid is used for one step precipitation of proteins and extraction of 5-HT and 5-HIAA. Precision of the assay has been increased by calibration of the instrument using serotonin-free plasma spiked with known amount of standards and N-w-methyl-5-hydroxytryptamine as internal standard. Integration of the peaks and calculations are achieved by a preprogrammed data module using ratio method. As little as 20 pg/ml of serotonin in the deproteinated sample can be detected using this procedure. In a group of surgical patients, plasma 5-HT concentration is (Mean +/- S D) 3.4 +/- 2.7 ng/ml and that of platelet 748.3 +/- 448.3 ng/10(9) platelets. In CSF, 5-HT is found to be 3.3 +/- 3.4 ng/ml and 5-HIAA is 15.1 +/- 7.3 ng/ml. A good correlation (r = 0.648, p less than .0001) is observed between 5-HT and 5-HIAA in CSF.     

In vitro plantlet regeneration and assessment of alkaloid contents from callus cultures of Ephedra foliata (Unth phog), a source of anti-asthmatic drugs

Ephedra foliata, (Gymnosperm) is a pharmaceutically important plant known for the last 5,000 years and has a number of medicinal properties. We describe here for the first time, a method for plant regeneration from callus established from axillary buds as explant, with the aim of optimizing alkaloids production in vitro. The tissue cultures initiated are being maintained for the last 3 years on Murashige and Skoog (Physiol Plant 15:473–497, 1962) medium containing 0.5 mg l^?1 each of 2, 4-D and Kin. Maintained callus cultures exhibited regeneration potential and maximum number (23.5 ± 0.44 shoots per culture vessel) of shoots with an average height (4.94 ± 0.23 cm) was achieved on MS medium containing combination of 0.25 mg l^?1 each of Kin, BA and 0.1 mg l^?1 of NAA. About 84.9 % regenerated shoots were rooted under ex vitro conditions on Soilrite^®, if their base was treated with 500 mg l^?1 of IBA for 5 min. The rooted plantlets were successfully acclimatized under greenhouse conditions with ≈80 % survival rate. We analyzed alkaloid contents of tissue culture raised plants/callus as affected by the different concentrations and combination of two additives, i.e., l-phenylalanine and IBA. The alkaloid production was higher in the in vitro grown cultures than field-grown plants. Highest alkaloid content was recorded in callus culture on M₅ medium having 0.5 mg l^?1 each of 2, 4-D and Kin, 100 mg l^?1 l-phenylalanine and 5 mg l^?1 IBA. The present protocol may be applicable for the large-scale cultivation of E. foliata and selection of cell line having higher secondary metabolite contents of this pharmaceutically important threatened plant species.     

Novel roles for O-linked glycans in protein folding

N-Glycosylation has long been linked to protein folding and quality control in the endoplasmic reticulum (ER). Recent work has shown that O-linked glycosylation and the corresponding glycosyltransferases also participate in this important function. Notably, Protein O-fucosyltransferase 1 (Ofut1/Pofut1), a soluble, ER localized enzyme that fucosylates Epidermal Growth Factor-like (EGF) repeats, functions as a chaperone involved in the proper localization of the Notch receptor in certain contexts. Pofut2, a related enzyme that modifies Thrombospondin type I repeats (TSRs), has also been hypothesized to play a role in the folding and quality control of TSR-containing proteins. Both enzymes only modify fully folded substrates suggesting that they are able to distinguish between folded and unfolded structures. Pofuts have known physiological relevance and are conserved across metazoans. Though consensus sequences for O-fucosylation have been established and structures of both Pofuts have been studied, the mechanism of how they participate in protein folding is not known. This article discusses past and recent advances made in novel roles for these protein O-glycosyltransferases.     

Protection of Shrimp Penaeus monodon from WSSV Infection Using Antisense Constructs

White spot syndrome caused by white spot syndrome virus (WSSV) is one of the most threatening diseases of shrimp culture industry. Previous studies have successfully demonstrated the use of DNA- and RNA-based vaccines to protect WSSV infection in shrimp. In the present study, we have explored the protective efficacy of antisense constructs directed against WSSV proteins, VP24, and VP28, thymidylate synthase (TS), and ribonucleotide reductase-2 (RR2) under the control of endogenous shrimp histone-3 (H3) or penaedin (Pn) promoter. Several antisense constructs were generated by inserting VP24 (pH3–VP24, pPn–VP24), VP28 (pH3–VP28, pPn–VP28), TS (pH3–TS, pPn–TS), and RR2 (pH3–RR2) in antisense orientation. These constructs were tested for their protective potential in WSSV infected cell cultures, and their effect on reduction of the viral load was assessed. A robust reduction in WSSV copy number was observed upon transfection of antisense constructs in hemocyte cultures derived from Penaeus monodon and Scylla serrata. When tested in vivo, antisense constructs offered a strong protection in WSSV challenged P. monodon. Constructs expressing antisense VP24 and VP28 provided the best protection (up to 90 % survivability) with a corresponding decrease in the viral load. Our work demonstrates that shrimp treated with antisense constructs present an efficient control strategy for combating WSSV infection in shrimp aquaculture.