Authors:M. KARUNAKARAN, N. V. NAIR, H. S. RHO and Y. H. LEE
Colletotrichum falcatum Went, the
causal agent of red rot of sugarcane produces a specialized infection structure
called appressorium, for penetrating the host. Environmental cues like surface
hydrophobicity and hardness tend to break the dormancy of the conidia and
initiate conidial germination. Conidial attachment is generally stronger on
hydrophobic surfaces, while hydrophilic surfaces do not permit conidial
attachment of C. falcatum. In vitro studies on conidial germination and
appressorium development were made to examine whether the Ca2+/calmodulin
dependent pathways are involved in appressorium formation in C. falcatum.
Effects of calcium chelator (EGTA), calcium channel blocker (methoxy
verampamil), calmodulin antagonists (chloropromazine, phenoxy benzamine and
W-7) and phospholipase C inhibitor (neomycin) were also examined to see whether
they can impair conidial germination and appressorium development. All these
chemicals were found to inhibit conidial germination and or appressorium
formation in C. falcatum. Chloropromazine and W-7 specifically inhibited
appressorium formation at the µM level. Exogenous addition of Ca2+
was found to restore the inhibition of conidial germination and appressorium
development by EGTA. These results suggest that the Ca2+/calmodulin signal
transduction pathway play an important role in the conidial morphogenesis and
appressorium development in C. falcatum.
Authors:A. N. Garg, A. Kumar, A. G. C. Nair and A. V. R. Reddy
Eight different brands of Trifala and its three constituents, Amalaki (Embilica officinalis), Bibhitaki (Terminalia bellirica) and Haritaki (T.chebula) were analyzed for 6 minor (Na, K, Mg, Ca, Cl and P) and 19 trace (Al, Ba, Br, Co, Cr, Cs, Fe, Eu, Hf, Hg, La, Mn, Rb, Sb, Sc, Se, Th, V and Zn) elements by instrumental neutron activation analysis (INAA). Two candidate reference materials Tea Leaves (TL-1) and Mixed Polish Herbs (MPH-2) were also analyzed as a part of Intercomparison Study besides several reference materials (RMs) for quality control. The samples along with RMs were irradiated with thermal neutrons in APSARA/Dhruva reactors at BARC, Mumbai and their activity measured on HPGe detector and 8K MCA system. Also Ni, Cu, Cd and Pb contents were determined by AAS. Bibhitaki is found to be enriched in Fe (0.98 mg/g), P (1.10 mg/g), Co (1.74 mg/g) and Se (240 ng/g) including alkali and alkaline earth metals. Availability of many nutrient elements such as Mg, Ca, K, Fe, and Se in Trifala is attributed to its usefulness in the treatment of liver disorder, heart ailments, hepatic diseases and cancer, as expectorant, powerful eye rejuvenator and an antioxidant.
Authors:A. Kumar, A. G. C. Nair, A. V. R. Reddy and A. N. Garg
Twenty bhasmas based on Ca, Fe, Zn, Hg, Ag, K, As, Cu, Sn and gemstones have been analyzed for main constituent elements along
with minor (Na, K, Mg, Ca, P), trace (Cr, Mn, Fe, Co, Cu, Zn, Hg) and toxic elements by instrumental neutron activation analysis
(INAA) including their C, H, N and S contents. Siddhamakaradhwaja, an Hg preparation and Swet parpati of K were found to be
stoichiometrically HgS and KNO3
Authors:R.N. Acharya, K. Sudarshan, A.G.C. Nair, Y.M. Scindia, A. Goswami, A.V.R. Reddy and S.B. Manohar
The guided thermal neutron beam at 100 MW Dhruva research reactor facility of Bhabha Atomic Research Centre (BARC) was used to carry out prompt gamma-ray neutron activation analysis (PGNAA). The prompt k0-factors have been determined for the isotopes of the elements H, B, K, Co, Cu, Ca, Ti, Cr, Cd, Ba, Hg and Gd with respect to 1951 keV gamma-line of 36Cl. The prompt k0-factors for H, Cl and Cu were also measured with respect to the 1381 keV gamma-line of 49Ti. Different samples like NH4Cl, Ti metal, cobalt chloride and other stoichiometric compounds and pure metals were used for this purpose. Prompt gamma-rays were accumulated using a 22% HPGe detector connected to a PC based 8k MCA in single mode counting. The energy calibration in the range of 100–8500 keV was carried out using gamma-rays from 152Eu and 60Co, and the prompt gamma-rays from 36Cl whereas the absolute detection efficiency for this energy range was determined using 152Eu and prompt gamma-rays from 36Cl and 49Ti.