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991.
Saleem Muhammad Hamzah Mfarrej Manar Fawzi Bani Alatawi Aishah Mumtaz Sahar Imran Muhammad Ashraf Muhammad Arslan Rizwan Muhammad Usman Kamal Ahmad Parvaiz Ali Shafaqat 《Journal of Plant Growth Regulation》2023,42(3):2053-2072
Journal of Plant Growth Regulation - Soil contamination with toxic heavy metals [such as arsenic (As)] is becoming a serious global problem due to rapid development of social economy. Silicon (Si),... 相似文献
992.
Bacillus subtilis mutant deficient in the major autolytic amidase and glucosaminidase is impaired in motility 总被引:5,自引:0,他引:5
Muhammad Harunur Rashid Akio Kuroda Junichi Sekiguchi 《FEMS microbiology letters》1993,112(2):135-140
Abstract The purified autolytic endo- β - N -acetylglucosaminidase of Bacillus subtilis AC327 was cleaved with cyanogen bromide, and the N-terminal amino acid sequence of one of the peptide fragments was determined. Then, a DNA fragment containing a part of the glucosaminidase gene was cloned into Escherichia coli JM109 using synthetic oligonucleotides as probes whose sequences had been deduced from the N-terminal amino acid sequence. Zymographic analysis showed that the resultant glucosaminidase-deficient strain lacked a 35-kDa lytic band in addition to a 90-kDa lytic one corresponding to the glucosaminidase. A double mutant strain deficient in the major two autolysins (amidase and glucosaminidase) exhibited greatly impaired motility on a swarm plate whereas the single mutant strains were motile. 相似文献
993.
994.
Insights into stereochemical features of sulphated carbohydrates: X-ray crystallographic and modelling investigations 总被引:1,自引:0,他引:1
Lamba Doriano; Glover Steven; Mackie William; Rashid Abdul; Sheldrick Bernard; Prez Serge 《Glycobiology》1994,4(2):151-163
The three-dimensional structures of the 2-, 3-, 4- and 6-monosulphatesof methyl -D-galactopyranoside have been determined by X-raycrystallography; the first two as the sodium salt, the thirdas both the sodium and potassium salts, and the fourth as apotassium salt. These represent the principal sulphated monomersof the carrageenan polysaccharides. The results extend our knowledgeof the stereochemical features, such as ring conformation, sulphategeometry, hydrogen bonding and cation co-ordination, which characterizesulphated monosaccharides. The stereochemical data have beenused to derive a mean geometry of the O-sulphate group and aset of force constants for use in molecular mechanics calculationson sulphated monosaccharides. These may be used in an extrapolationof the populations of stable conformers of related oligo- andpolysaccharides. crystal structures molecular mechanics O-sulphated carbohydrates X-ray diffraction 相似文献
995.
Patricia Q. Tran Samantha C. Bachand Peter B. McIntyre Benjamin M. Kraemer Yvonne Vadeboncoeur Ismael A. Kimirei Rashid Tamatamah Katherine D. McMahon Karthik Anantharaman 《The ISME journal》2021,15(7):1971
Lake Tanganyika (LT) is the largest tropical freshwater lake, and the largest body of anoxic freshwater on Earth’s surface. LT’s mixed oxygenated surface waters float atop a permanently anoxic layer and host rich animal biodiversity. However, little is known about microorganisms inhabiting LT’s 1470 meter deep water column and their contributions to nutrient cycling, which affect ecosystem-level function and productivity. Here, we applied genome-resolved metagenomics and environmental analyses to link specific taxa to key biogeochemical processes across a vertical depth gradient in LT. We reconstructed 523 unique metagenome-assembled genomes (MAGs) from 34 bacterial and archaeal phyla, including many rarely observed in freshwater lakes. We identified sharp contrasts in community composition and metabolic potential with an abundance of typical freshwater taxa in oxygenated mixed upper layers, and Archaea and uncultured Candidate Phyla in deep anoxic waters. Genomic capacity for nitrogen and sulfur cycling was abundant in MAGs recovered from anoxic waters, highlighting microbial contributions to the productive surface layers via recycling of upwelled nutrients, and greenhouse gases such as nitrous oxide. Overall, our study provides a blueprint for incorporation of aquatic microbial genomics in the representation of tropical freshwater lakes, especially in the context of ongoing climate change, which is predicted to bring increased stratification and anoxia to freshwater lakes.Subject terms: Biogeochemistry, Limnology, Microbial ecology, Freshwater ecology 相似文献
996.
Ramesh Ramapanicker Nasir Baig Rashid Baig Kavita De Srinivasan Chandrasekaran 《Journal of peptide science》2009,15(12):849-855
Protection of the amino group and activation of the carboxylic acid groups are the most important steps associated with any peptide synthesis protocol; hence, a one‐pot process to achieve these is highly desirable. A possible strategy is to use pentafluorophenyl carbonates to simultaneously protect the amino group as a carbamate derivative and activate the carboxylic acid group as a pentafluorophenyl ester. A detailed study is carried out to understand the scope and limitations of this method using five different pentaflurophenyl carbonates. The efficiency of these one‐pot reactions depends largely on the nature of the pentafluorophenyl carbonates and also on the nature of the amino acids. Electron deficient and sterically less demanding carbonates reacted faster than the others, whereas amino acids with longer aliphatic side chains gave better yields than more polar amino acids. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
997.
998.
999.
David Harris Abdul Rashid Ghazal Miraj Muhammad Arif Muhammed Yunas 《Plant and Soil》2008,306(1-2):3-10
A series of on-station trials was implemented between 2002 and 2006 to assess the response of wheat (Triticum aestivum L.) and chickpea (Cicer arietinum) to zinc (Zn) added by soaking seeds (priming) in solutions of ZnSO4 before sowing. Wheat seed was primed for 10 h in 0.3% Zn and chickpea for 6 h in 0.05% Zn. Seed treatments increased the
seed concentration in wheat from 27 to 470 mg/kg and in chickpea from 49 to 780 mg/kg. Priming wheat seeds with 0.3% Zn significantly
increased the mean shoot dry mass, Zn concentration and Zn uptake of 15-day-old seedlings relative to non-primed controls
and seeds primed with water alone. Using 0.4% Zn further increased shoot Zn concentration but depressed shoot dry mass to
the level of the non-primed control. In seven trials, mean grain yield of wheat was significantly increased from 2.28 to 2.42 t/ha
(6%) by priming with water alone and to 2.61 t/ha (14%) by priming with 0.3% Zn. Mean grain yield of chickpea in seven trials
was increased significantly from 1.39 to 1.65 t/ha (19%) by priming seeds with 0.05% Zn. The effect of priming chickpea seeds
with water was intermediate (1.49 t/ha) and not statistically separable from the non-primed and zinc-primed treatments. Increased
grain yield due to priming in both crops was associated with increases in total biomass but there was no significant effect
of priming on harvest index. In addition to increasing yield, priming seeds with Zn also significantly increased grain zinc
concentration, by 12% in wheat (mean of three trials) and by 29% in chickpea (one trial) and the total amount of Zn taken
up by the grain (by 27% in wheat and by 130% in chickpea). Using ZnSO4 to prime seeds was very cost-effective, with net benefit-to-cost ratios of 75 for wheat and 780 for chickpea.
An erratum to this article can be found at 相似文献
1000.
Gell C Sabir T Westwood J Rashid A Smith DA Harris SA Stockley PG 《Journal of molecular biology》2008,384(1):264-278
We have examined the folding ensembles present in solution for a series of RNA oligonucleotides that encompass the replicase translational operator stem-loop of the RNA bacteriophage MS2. Single-molecule (SM) fluorescence assays suggest that these RNAs exist in solution as ensembles of differentially base-paired/base-stacked states at equilibrium. There are two distinct ensembles for the wild-type sequence, implying the existence of a significant free energy barrier between “folded” and “unfolded” ensembles. Experiments with sequence variants are consistent with an unfolding mechanism in which interruptions to base-paired duplexes, in this example by the single-stranded loop and a single-base bulge in the base-paired stem, as well as the free ends, act as nucleation points for unfolding. The switch between folded and unfolded ensembles is consistent with a transition that occurs when all base-pairing and/or base-stacking interactions that would orientate the legs of the RNA stem are broken. Strikingly, a U-to-C replacement of a residue in the loop, which creates a high-affinity form of the operator for coat protein binding, results in dramatically different (un)folding behaviour, revealing distinct subpopulations that are either stabilised or destabilised with respect to the wild-type sequence. This result suggests additional reasons for selection against the C-variant stem-loop in vivo and provides an explanation for the increased affinity. 相似文献