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Tapas K. Nandi Hridoy R. Bairagya Bishnu P. Mukhopadhyay K. Sekar Dipankar Sukul Asim K. Bera 《Journal of biosciences》2009,34(1):27-34
The role of invariant water molecules in the activity of plant cysteine protease is ubiquitous in nature. On analysing the
11 different Protein DataBank (PDB) structures of plant thiol proteases, the two invariant water molecules W1 and W2 (W220
and W222 in the template 1PPN structure) were observed to form H-bonds with the Ob atom of Asn 175. Extensive energy minimization and molecular dynamics simulation studies up to 2 ns on all the PDB and solvated
structures clearly revealed the involvement of the H-bonding association of the two water molecules in fixing the orientation
of the asparagine residue of the catalytic triad. From this study, it is suggested that H-bonding of the water molecule at
the W1 invariant site better stabilizes the Asn residue at the active site of the catalytic triad. 相似文献
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Relationships between induced high leaf intercellular CO2 concentrations, leaf K+ and NO3 ? ion movement and early fruit formation under macronutrient limitation are not well understood. We examined the effects and interactions of reduced K/N input treatments on leaf intercellular CO2, photosynthesis rate, carboxylation and water use efficiency, berry formation as well as leaf/fruit K+, NO3 ? and photosynthate retention of strawberry (Fragaria × ananassa Duch.) to enhance low-input agriculture. The field study was conducted in Nova Scotia, eastern Canada during 2009–2010. The experimental treatments consisted of five K2O rates (0, 6, 12, 18, and 24 kg ha?1) and five N rates (0, 5, 10, 15, and 20 kg ha?1), representing respectively, 0, 25, 50, 75, and 100 % of regular macronutrient recommendations based on the soil testing. The treatments were arranged in a split-plot design with three blocks in the field. The cultivar was ‘Mira’, a June-bearing crop. The results showed that strawberry plants treated with 25 %-reduced inputs could induce significantly higher leaf intercellular CO2 concentrations to improve plant photosynthesis, carboxylation and water use efficiency and translocation of leaf/fruit K+ and dissolved solids, which could advance berry formation by 6 days and produce significantly higher marketable yields (P < 0.05). Higher leaf intercellular CO2 inhibited leaf/fruit NO3 ? ion retention, but this inhibition did not occur in leaf/fruit K+ retention. Linear interactions of the K/N treatments were significant on fruit marketable yields, intercellular CO2, net photosynthesis, leaf transpiration rates, and leaf temperatures (P < 0.05). It was concluded that higher leaf CO2 could enhance plant photosynthesis, promote plant carboxylation and water use efficiency, and advance berry formation, but it could inhibit leaf NO3 ? retention. This inhibition did not find in leaf K+ ion and dissolved solid retention. Overlay co-limitation of leaf intercellular CO2 and translocation of leaf/fruit K+/NO3 ? and total dissolved solids could constrain more fruit formation attributes under full macronutrient supply than reduced inputs. It was suggested that low input would be an optimal and sustainable option for improving small fruit crop physiological development and dealing with macronutrient deficiency challenge. 相似文献
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Mingyue Wang Pranab K Mukherjee Jyotsna Chandra Ali Abdul Lattif Thomas S McCormick Mahmoud A Ghannoum 《BMC microbiology》2008,8(1):31
Background
We have previously shown that supernatant from Candida albicans (CA) culture contains a Secretory Interleukin (IL)-12 Inhibitory Factor (CA-SIIF), which inhibits IL-12 production by human monocytes. However, the effect of CA-SIIF on secretion of other cytokines by monocytes is unknown, and detailed characterization of this factor has not been performed. 相似文献78.
Dana M. Bergstrom George R. Stewart Patricia M. Selkirk Susanne Schmidt 《Oecologia》2002,130(2):309-314
'15N signatures of fossil peat were used to interpret past ecosystem processes on tectonically active subantarctic Macquarie Island. By comparing past vegetation reconstructed from the fossil record with present-day vegetation analogues, our evidence strongly suggests that changes in the '15N signatures of fossil peat at this location reflect mainly past changes in the proportion of plant nitrogen derived from animal sources. Associated with uplift above sea level over the past 8,500 years, fossil records in two peat deposits on the island chronicle a change from coastal vegetation with fur and elephant seal disturbance to the existing inland herbfield. Coupled with this change are synchronous changes in the '15N signatures of peat layers. At two sites 15N-enriched peat '15N signatures of up to +17 were associated with a high abundance of pollen of the nitrophile Callitriche antarctica (Callitrichaceae). At one site fossil seal hair was also associated with enriched peat '15N. Less 15N enriched '15N signatures (e.g. -1.9 to +3.9) were measured in peat layers which lacked animal associated C. antarctica and Acaena spp. Interpretation of a third peat profile indicates continual occupation of a ridge site by burrowing petrels for most of the Holocene. We suggest that 15N signatures of fossil peat remained relatively stable with time once deposited, providing a significant new tool for interpreting the palaeoecology. 相似文献
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