DORN1/P2K1 and purino-calcium signalling in plants: making waves with extracellular ATP.

BACKGROUND AND AIMS:Extracellular ATP governs a range of plant functions, including cell viability, adaptation and cross-kingdom interactions. Key functions of extracellular ATP in leaves and roots may involve an increase in cytosolic free calcium as a second messenger ('calcium signature'). The main aim here was to determine to what extent leaf and root calcium responses require the DORN1/P2K1 extracellular ATP receptor in Arabidopsis thaliana. The second aim was to test whether extracellular ATP can generate a calcium wave in the root. METHODS:Leaf and root responses to extracellular ATP were reviewed for their possible links to calcium signalling and DORN1/P2K1. Leaves and roots of wild type and dorn1 plants were tested for cytosolic calcium increase in response to ATP, using aequorin. The spatial abundance of DORN1/P2K1 in the root was estimated using green fluorescent protein. Wild type roots expressing GCaMP3 were used to determine the spatial variation of cytosolic calcium increase in response to extracellular ATP. KEY RESULTS:Leaf and root ATP-induced calcium signatures differed markedly. The leaf signature was only partially dependent on DORN1/P2K1, while the root signature was fully dependent. The distribution of DORN1/P2K1 in the root supports a key role in the generation of the apical calcium signature. Root apical and sub-apical calcium signatures may operate independently of each other but an apical calcium increase can drive a sub-apical increase, consistent with a calcium wave. CONCLUSION:DORN1 could underpin several calcium-related responses but it may not be the only receptor for extracellular ATP in Arabidopsis. The root has the capacity for a calcium wave, triggered by extracellular ATP at the apex

Comparative evaluation of the antimicrobial susceptibility and cytotoxicity of husk extract of Cocos nucifera and chlorhexidine as irrigating solutions against Enterococcus Faecalis, Prevotella Intermedia and Porphyromonas Gingivalis – An in-vitro study

Aim and Background: The aim of the present study is to evaluate and compare the antimicrobial susceptibility and cytotoxicity of Cocos nucifera and chlorhexidine (CHX) as irrigating solutions against Enterococcus faecalis, Prevotella intermedia, and Porphyromonas gingivalis. Materials and Methods: The ethanolic extract of husk of C. nucifera was prepared. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extract were determined using the serial broth dilution method and its cytotoxicity was evaluated against human periodontal fibroblasts using 3-(4,5-dimethyl-thiazole-2-yl)-2,5-diphenyl tetrazolium bromide assay. Antibacterial susceptibility for two irrigating solutions, namely 2% CHX gluconate irrigant (Group I) and 1.5% C. nucifera husk irrigant (Group II), was tested against P. gingivalis, P. intermedia, and E. faecalis. Results: The MIC and MBC of C. nucifera husk extract for P. gingivalis were 468.75 μg/ml and 1562.5 μg/ml, for P. intermedia were 48.8 μg/ml and 1875 μg/ml, and for E. faecalis were 1562.5 μg/ml and 3750 μg/ml, respectively. The extract was nontoxic to the human periodontal fibroblast. Both the materials have shown similar antibacterial susceptibility and no difference was observed at baseline, 10, 30, and 60 min using two-way repeated measures of ANOVA. However, a statistically significant difference was observed between different time points for P. gingivalis and P. intermedia using Bonferroni multiple comparison test (f = 826.1390, P ≤ 0.05). Conclusion: 1.5% of ethanolic husk extract of C. nucifera has a significant antibacterial action against polymicrobial dental biofilm and its activity is comparable to that of 2% CHX which validates its use as a future irrigating solution for overcoming bacterial resistance with synthetic agents

Hydrological processes in glacierized high-altitude basins of the western Himalayas

Western Himalaya is a strategically important region, where the water resources are shared by China, India and Pakistan. The economy of the region is largely dependent on the water resources delivered by snow and glacier melt. The presented study used stable isotopes of water to further understand the basin-scale hydro-meteorological, hydrological and recharge processes in three high-altitude mountainous basins of the western Himalayas. The study provided new insights in understanding the dominant factors affecting the isotopic composition of the precipitation, snowpack, glacier melt, streams and springs. It was observed that elevation-dependent post-depositional processes and snowpack evolution resulted in the higher isotopic altitude gradient in snowpacks. The similar temporal trends of isotopic signals in rivers and karst springs reflect the rapid flow transfer due to karstification of the carbonate aquifers. The attenuation of the extreme isotopic input signal in karst springs appears to be due to the mixing of source waters with the underground karst reservoirs. Basin-wise, the input–output response demonstrates the vital role of winter precipitation in maintaining the perennial flow in streams and karst springs in the region. Isotopic data were also used to estimate the mean recharge altitude of the springs

3rd National Conference on Image Processing, Computing, Communication, Networking and Data Analytics

This volume contains contributed articles presented in the conference NCICCNDA 2018, organized by the Department of Computer Science and Engineering, GSSS Institute of Engineering and Technology for Women, Mysore, Karnataka (India) on 28th April 2018