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61.
Maryse Bourgault Heidi A. Webber Karine Chenu Garry J. OLeary Thomas Gaiser Stefan Siebert Fernanda Dreccer Neil Huth Glenn J. Fitzgerald Michael Tausz Frank Ewert 《Global Change Biology》2020,26(7):4079-4093
Early vigour in wheat is a trait that has received attention for its benefits reducing evaporation from the soil surface early in the season. However, with the growth enhancement common to crops grown under elevated atmospheric CO2 concentrations (e[CO2]), there is a risk that too much early growth might deplete soil water and lead to more severe terminal drought stress in environments where production relies on stored soil water content. If this is the case, the incorporation of such a trait in wheat breeding programmes might have unintended negative consequences in the future, especially in dry years. We used selected data from cultivars with proven expression of high and low early vigour from the Australian Grains Free Air CO2 Enrichment (AGFACE) facility, and complemented this analysis with simulation results from two crop growth models which differ in the modelling of leaf area development and crop water use. Grain yield responses to e[CO2] were lower in the high early vigour group compared to the low early vigour group, and although these differences were not significant, they were corroborated by simulation model results. However, the simulated lower response with high early vigour lines was not caused by an earlier or greater depletion of soil water under e[CO2] and the mechanisms responsible appear to be related to an earlier saturation of the radiation intercepted. Whether this is the case in the field needs to be further investigated. In addition, there was some evidence that the timing of the drought stress during crop growth influenced the effect of e[CO2] regardless of the early vigour trait. There is a need for FACE investigations of the value of traits for drought adaptation to be conducted under more severe drought conditions and variable timing of drought stress, a risky but necessary endeavour. 相似文献
62.
Eric Dumonteil Ardem Elmayan Alicia Majeau Weihong Tu Brandy Duhon Preston Marx Wendy Wolfson Garry Balsamo Claudia Herrera 《PLoS neglected tropical diseases》2020,14(12)
BackgroundChagas disease is a neglected zoonosis of growing concern in the southern US, caused by the parasite Trypanosoma cruzi. We genotyped parasites in a large cohort of PCR positive dogs to shed light on parasite transmission cycles and assess potential relationships between parasite diversity and serological test performance.Methodology/principal findingsWe used a metabarcoding approach based on deep sequencing of T. cruzi mini-exon marker to assess parasite diversity. Phylogenetic analysis of 178 sequences from 40 dogs confirmed the presence of T. cruzi discrete typing unit (DTU) TcI and TcIV, as well as TcII, TcV and TcVI for the first time in US dogs. Infections with multiple DTUs occurred in 38% of the dogs. These data indicate a greater genetic diversity of T. cruzi than previously detected in the US. Comparison of T. cruzi sequence diversity indicated that highly similar T. cruzi strains from these DTUs circulate in hosts and vectors in Louisiana, indicating that they are involved in a shared T. cruzi parasite transmission cycle. However, TcIV and TcV were sampled more frequently in vectors, while TcII and TcVI were sampled more frequently in dogs.Conclusions/significanceThese observations point to ecological host-fitting being a dominant mechanism involved in the diversification of T. cruzi-host associations. Dogs with negative, discordant or confirmed positive T. cruzi serology harbored TcI parasites with different mini-exon sequences, which strongly supports the hypothesis that parasite genetic diversity is a key factor affecting serological test performance. Thus, the identification of conserved parasite antigens should be a high priority for the improvement of current serological tests. 相似文献
63.
Hanisch Justin R. Connor Stephanie J. Scrimgeour Garry J. Cobbaert Danielle 《Wetlands Ecology and Management》2020,28(2):199-216
Wetlands Ecology and Management - We compared a rapid bioassessment protocol (Traveling Sweep Approach [TSA]) with a more conventional time intensive protocol (Composite Transect Approach [CTA]) to... 相似文献
64.
Chloe Robins Yue Liu Wen Fan Duc M. Duong Jacob Meigs Nadia V. Harerimana Ekaterina S. Gerasimov Eric B. Dammer David J. Cutler Thomas G. Beach Eric M. Reiman Philip L. De Jager David A. Bennett James J. Lah Aliza P. Wingo Allan I. Levey Nicholas T. Seyfried Thomas S. Wingo 《American journal of human genetics》2021,108(3):400-410
65.
Kathryn E. Keenan Lampros C. Kourtis Thor F. Besier Derek P. Lindsey Garry E. Gold Scott L. Delp 《Computer methods in biomechanics and biomedical engineering》2013,16(4):415-422
Cartilage material properties are important for understanding joint function and diseases, but can be challenging to obtain. Three biphasic material properties (aggregate modulus, Poisson's ratio and permeability) can be determined using an analytical or finite element model combined with optimisation to find the material properties values that best reproduce an experimental creep curve. The purpose of this study was to develop an easy-to-use resource to determine biphasic cartilage material properties. A Cartilage Interpolant Response Surface was generated from interpolation of finite element simulations of creep indentation tests. Creep indentation tests were performed on five sites across a tibial plateau. A least-squares residual search of the Cartilage Interpolant Response Surface resulted in a best-fit curve for each experimental condition with corresponding material properties. These sites provided a representative range of aggregate moduli (0.48–1.58 MPa), Poisson's ratio (0.00–0.05) and permeability (1.7 × 10? 15–5.4 × 10? 15 m4/N s) values found in human cartilage. The resource is freely available from https://simtk.org/home/va-squish. 相似文献
66.
Zlatko Janeba Noha Maklad Morris J. Robins 《Nucleosides, nucleotides & nucleic acids》2013,32(10-12):1729-1743
Copper(I)-catalyzed 5-endo-dig cyclizations of 5-(alkyn-1-yl)uracil derivatives had given poor yields of substituted furo[2, 3]pyrimidin-2-ones unless the uracil ring was substituted at N1 with alkyl or glycosyl groups. This limited flexibility for the synthesis of analogues with varied substituents at N3 and/or C6 of the furo[2, 3]pyrimidin-2-one core has been overcome with 5-(3-hydroxyalkyn-1-yl)uracil compounds with no substituent at N1. Manipulation of the side-chain hydroxyl group gives access to additional furo[2,3-d]pyrimidin-2-one analogues. 相似文献
67.
Ganapathi R. Revankar Roland K. Robins 《Nucleosides, nucleotides & nucleic acids》2013,32(5-6):709-724
Abstract A general and stereospecific method has been developed for the direct preparation of βD-ribofuranosyl, βD-arabinofuranosyl and 2-deoxy-βD-erythro-pentofuranosyl derivatives of a number of nitrogen heterocycles. The azoles thus far employed include appropriately substituted pyrrole, pyrazole, imidazole, 1,2,4-triazole, indole, imidazo[4,5-c]pyridine, pyrrolo[2,3-d]pyrimidine, pyrro10[3,2-c]pyridine, pyrrolo[4,2-c]pyrimidine, purine, pyrazolo[3,4-b]pyridine and pyrazolo-[3,4-d]pyrimidine. This simple high-yield methodology provided a facile route to the large-scale preparation of biologically significant nucleo-sides, such as 2′-deoxyribavirin, 2-chloro-2′-deoxyadenosine, tuber-cidin, Z'-deoxytubercidin, =sangivarnycin, 2′-deoxytoyocamycin, cade-guomycin, 2′-deoxycadeguomycin, G-cadeguomycin, kanagawamicin, 2′-deoxy-3-deazaguanosine, sG, brunfelsarnidine ribonucleoside and 2′-deoxyribofuranosyl derivative of the antibiotic SF-2140. This procedure appears to be considerably superior to the previously reported glycosylation methods. 相似文献
68.
Kandasamy Ramasamy Roland K. Robins Ganapathi R. Revankar 《Nucleosides, nucleotides & nucleic acids》2013,32(3):385-392
Abstract A synthesis of 2,4-dideazaribavirin ( 2 ), brunfelsamidine ribonucleoside ( 8c ) and certain related derivatives are described for the first time using the stereospecific sodium salt glycosylation procedure. Glycosylation of the sodium salt of pyrrole-3-carbonitrile ( 4 ) with 1-chloro-2, 3-O-t-isopropylidene-5-O-t-butyldimethylsilyl-α-D-ribofuranose ( 5 ) gave exclusively the corresponding blocked nucleoside ( 6 ) with β-anomeric configuration, which on deprotection provided 1-β-D-ribofuranosylpyrrole-3-carbonitrile ( 7 ). Functional group tranformation of 7 gave 2 , 8c and related 3-substituted pyrrole ribonucleosides. These compounds are devoid of any significant antiviral/antitumor activity invitro. 相似文献
69.
Roland K. Robins 《Nucleosides, nucleotides & nucleic acids》2013,32(3):205-231
Abstract A review of the potential role of cAMP and cGMP as hormonal regulators of tumor cell proliferation, metastases and lymphocyte activation reveals that several synthetic purine nucleoside 3′,5′-cyclic monophosphates are more potent and more selective in modulating certain specific responses than the parent natural cyclic nucleotides. cAMP derivatives have been prepared which will temporarily restore transformed cells to the normal phenotype. cAMP analogs may well be found which will selectively inhibit tumor metastases. Certain cGMP analogs could selectively stimulate the lymphocyte response toward the destruction of tumor cells. The synthesis of new cyclic nucleotides should provide unique nontoxic agents that could combat neoplasia on a hormonal basis. 相似文献
70.
Ganesh D. Kini William J. Hennen Roland K. Robins 《Nucleosides, nucleotides & nucleic acids》2013,32(3):581-587
Abstract A new, facile synthesis of 7-methyl-8-oxoguanosine is reported. 2-Chloro-7-methylpurine-6, 8-dione (5) was silylated with hexamethyldi-silazane and the silylated intermediate, 6, glycosylated with 1-0-acetyl-2, 3, 5-tri-0-benzoyl-D-ribofuranose to yield 2-chloro-7-methyl-9-(2′, 3′,-5′-tri-0-benzoyl-β-D-ribofuranosyl) purin-6, 8-dione (8). Deprotection of 8 with sodium hydroxide in aqueous methanol gave 2-chloro-7-methyl-9-(β-D-ribofuranosyl) purine-6,8-dione (9), which was aminated with liquid ammonia or methanolic ammonia to yield 7-methyl-8-oxoguanosine (3). 相似文献