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271.
Ninad?Avinash?MungiEmail authorView authors OrcID profile Nicholas?C.?Coops K.?Ramesh Gopal?S.?Rawat 《Biological invasions》2018,20(7):1849-1863
Presently, it is debated if regional conservation efforts can alone resolve the ecological problems that global climatic changes could bring. Biological invasion is one of such concerns. In the present study, we modeled how change in global climate and regional anthropogenic pressure can impact the distribution of invasive Lantana camara in the Upper Ganga valley of the Western Himalaya (India). The forest in the study area was stratified into 1 km2 grid and two 15 m radius plot were located in each of the forest types in the grid, for recording Lantana presence. In total, 2221 plots were sampled covering 22% of forest. We used predictors representing the climate, forest patch size, fire and natural disaster variables for modeling the species distribution using maximum entropy algorithm. We further simulated 12 future landscape scenarios based on the global trends of these parameters. The present species—environment relationship was projected to these future landscape scenarios. Lantana was presently estimated to spread in 231 km2 of the study area. It invaded larger forest patches in the sub-tropical region, and smaller disturbed forest patches in the warm and cold temperate region. Increased distribution of Lantana was projected across all the future scenarios. The study revealed how global climate changes and regional anthropogenic pressure can have a synergistic effect on the expansion of invasive species in the future. It thus questions the efficiency of conducting only regional efforts in absence of global initiative to reduce the greenhouse gases emission. 相似文献
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273.
Pierre‐François Perroud Fabian B. Haas Manuel Hiss Kristian K. Ullrich Alessandro Alboresi Mojgan Amirebrahimi Kerrie Barry Roberto Bassi Sandrine Bonhomme Haodong Chen Juliet C. Coates Tomomichi Fujita Anouchka Guyon‐Debast Daniel Lang Junyan Lin Anna Lipzen Fabien Nogué Melvin J. Oliver Inés Ponce de León Ralph S. Quatrano Catherine Rameau Bernd Reiss Ralf Reski Mariana Ricca Younousse Saidi Ning Sun Péter Szövényi Avinash Sreedasyam Jane Grimwood Gary Stacey Jeremy Schmutz Stefan A. Rensing 《The Plant journal : for cell and molecular biology》2018,95(1):168-182
274.
Shruti Arya Avinash K. Singh Karishma Bhasne Priyanka Dogra Anindya Datta Payel Das Samrat Mukhopadhyay 《Biophysical journal》2018,114(11):2540-2551
Protein hydration water plays a fundamentally important role in protein folding, binding, assembly, and function. Little is known about the hydration water in intrinsically disordered proteins that challenge the conventional sequence-structure-function paradigm. Here, by combining experiments and simulations, we show the existence of dynamical heterogeneity of hydration water in an intrinsically disordered presynaptic protein, namely α-synuclein, implicated in Parkinson’s disease. We took advantage of nonoccurrence of cysteine in the sequence and incorporated a number of cysteine residues at the N-terminal segment, the central amyloidogenic nonamyloid-β component (NAC) domain, and the C-terminal end of α-synuclein. We then labeled these cysteine variants using environment-sensitive thiol-active fluorophore and monitored the solvation dynamics using femtosecond time-resolved fluorescence. The site-specific femtosecond time-resolved experiments allowed us to construct the hydration map of α-synuclein. Our results show the presence of three dynamically distinct types of water: bulk, hydration, and confined water. The amyloidogenic NAC domain contains dynamically restrained water molecules that are strikingly different from the water molecules present in the other two domains. Atomistic molecular dynamics simulations revealed longer residence times for water molecules near the NAC domain and supported our experimental observations. Additionally, our simulations allowed us to decipher the molecular origin of the dynamical heterogeneity of water in α-synuclein. These simulations captured the quasi-bound water molecules within the NAC domain originating from a complex interplay between the local chain compaction and the sequence composition. Our findings from this synergistic experimental simulation approach suggest longer trapping of interfacial water molecules near the amyloidogenic hotspot that triggers the pathological conversion into amyloids via chain sequestration, chain desolvation, and entropic liberation of ordered water molecules. 相似文献
275.
Renner SM Natarajan RN Patwardhan AG Havey RM Voronov LI Guo BY Andersson GB An HS 《Journal of biomechanics》2007,40(6):1326-1332
A 3-D finite element model (FEM) of the lumbar spine (L1-S1) was used to determine the effect of a large compressive follower pre-load on range of motions (ROM) in all three planes. The follower load modeled in the FEM produced minimal vertebral rotations in all the three planes. The model was validated by comparing the disc compression at all levels in the lumbar spine with the corresponding results obtained by compressing 10 cadevaric lumbar spines (L1-S1) using the follower load technique described by Patwardhan et al. [1999. A follower load increases the load-carrying capacity of the lumbar spine in compression. Spine 24(10), 1003-1009]. Further validation of the model was performed by comparing the lateral bending and torsion response without pre-load and the flexion-extension response without pre-load and with an 800 N follower pre-load with those obtained using cadaver lumbar spines. Following validation, the FEM was subjected to bending moments in all three planes with and without compressive follower pre-loads of up to 1200 N. Disc compression values and the flexion-extension range of motion under 800 N follower pre-load predicted by the FEM compared well with in vitro results. The current model showed that compressive follower pre-load decreased total as well as segmental ROM in flexion-extension by up to 18%, lateral bending by up to 42%, and torsion by up to 26%. 相似文献
276.
Schwarz BA Sambandam A Maillard I Harman BC Love PE Bhandoola A 《Journal of immunology (Baltimore, Md. : 1950)》2007,178(4):2008-2017
To generate T cells throughout adult life, the thymus must import hemopoietic progenitors from the bone marrow via the blood. In this study, we establish that thymus settling is selective. Using nonirradiated recipient mice, we found that hemopoietic stem cells were excluded from the thymus, whereas downstream multipotent progenitors (MPP) and common lymphoid progenitors rapidly generated T cells following i.v. transfer. This cellular specificity correlated with the expression of the chemokine receptor CCR9 by a subset of MPP and common lymphoid progenitors but not hemopoietic stem cells. Furthermore, CCR9 expression was required for efficient thymus settling. Finally, we demonstrate that a prethymic signal through the cytokine receptor fms-like tyrosine kinase receptor-3 was required for the generation of CCR9-expressing early lymphoid progenitors, which were the most efficient progenitors of T cells within the MPP population. We conclude that fms-like tyrosine kinase receptor-3 signaling is required for the generation of T lineage-competent progenitors, which selectively express molecules, including CCR9, that allow them to settle within the thymus. 相似文献
277.
Shenoy AR Capuder M Draskovic P Lamba D Visweswariah SS Podobnik M 《Journal of molecular biology》2007,365(1):211-225
Cyclic nucleotide monophosphate (cNMP) hydrolysis in bacteria and eukaryotes is brought about by distinct cNMP phosphodiesterases (PDEs). Since these enzymes differ in amino acid sequence and properties, they have evolved by convergent evolution. Cyclic NMP PDEs cleave cNMPs to NMPs, and the Rv0805 gene product is, to date, the only identifiable cNMP PDE in the genome of Mycobacterium tuberculosis. We have shown that Rv0805 is a cAMP/cGMP dual specificity PDE, and is unrelated in amino acid sequence to the mammalian cNMP PDEs. Rv0805 is a dimeric, Fe(3+)-Mn(2+) binuclear PDE, and mutational analysis demonstrated that the active site metals are co-ordinated by conserved aspartate, histidine and asparagine residues. We report here the structure of the catalytic core of Rv0805, which is distantly related to the calcineurin-like phosphatases. The crystal structure of the Rv0805 dimer shows that the active site metals contribute to dimerization and thus play an additional structural role apart from their involvement in catalysis. We also present the crystal structures of the Asn97Ala mutant protein that lacks one of the Mn(2+) co-ordinating residues as well as the Asp66Ala mutant that has a compromised cAMP hydrolytic activity, providing a structural basis for the catalytic properties of these mutant proteins. A molecule of phosphate is bound in a bidentate manner at the active site of the Rv0805 wild-type protein, and cacodylate occupies a similar position in the crystal structure of the Asp66Ala mutant protein. A unique substrate binding pocket in Rv0805 was identified by computational docking studies, and the role of the His140 residue in interacting with cAMP was validated through mutational analysis. This report on the first structure of a bacterial cNMP PDE thus significantly extends our molecular understanding of cAMP hydrolysis in class III PDEs. 相似文献
278.
279.
Md Delowar Hossain Zhenjing Liu Minghao Zhuang Xingxu Yan Gui‐Liang Xu Chaitanya Avinash Gadre Abhishek Tyagi Irfan Haider Abidi Cheng‐Jun Sun Hoilun Wong Alexander Guda Yufeng Hao Xiaoqing Pan Khalil Amine Zhengtang Luo 《Liver Transplantation》2019,9(10)
The proper choice of nonprecious transition metals as single atom catalysts (SACs) remains unclear for designing highly efficient electrocatalysts for hydrogen evolution reaction (HER). Herein, reported is an activity correlation with catalysts, electronic structure, in order to clarify the origin of reactivity for a series of transition metals supported on nitrogen‐doped graphene as SACs for HER by a combination of density functional theory calculations and electrochemical measurements. Only few of the transition metals (e.g., Co, Cr, Fe, Rh, and V) as SACs show good catalytic activity toward HER as their Gibbs free energies are varied between the range of –0.20 to 0.30 eV but among which Co‐SAC exhibits the highest electrochemical activity at 0.13 eV. Electronic structure studies show that the energy states of active valence dz2 orbitals and their resulting antibonding state determine the catalytic activity for HER. The fact that the antibonding state orbital is neither completely empty nor fully filled in the case of Co‐SAC is the main reason for its ideal hydrogen adsorption energy. Moreover, the electrochemical measurement shows that Co‐SAC exhibits a superior hydrogen evolution activity over Ni‐SAC and W‐SAC, confirming the theoretical calculation. This systematic study gives a fundamental understanding about the design of highly efficient SACs for HER. 相似文献
280.
Avinash P. Sattur Je-Hyuk Lee Ki-Bang Song T. Panda Chul-Ho Kim Sang-Ki Rhee B. Gokul 《Biotechnology and Bioprocess Engineering》2000,5(3):153-158
Vancomycin belongs to the vancomycin-ristocetin family of glycopeptides, and is a subclass of linear sugar containing peptides
composed of seven amino acids. Its stereochemical configuration forms the basis of a particular mode of action, though its
complexation with the D-alanyl-D-alanine terminus of peptidoglycon monomer. The glycosylated hexapeptide chain consists of
chloro-β-hydroxytyrosines, p-hydroxyphenylglycines, N-methylleucine and aspartic acid forms a rigid molecular frame work and
gives the difficulty in the analysis. Vancomycin in the serum samples is usually estimated by liquid chromatography and the
bacterial sensitivity was genereally tested by the microbiological assay. The present review deals with the qualitative, quantitative,
microbiological and immunological assays and the comparison of the quantitative methods. Clinical implications of vancomycin
have also been cited in the review. 相似文献