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941.
Paul G. Schaberg Rakesh Minocha Stephanie Long Joshua M. Halman Gary J. Hawley Christopher Eagar 《Trees - Structure and Function》2011,25(6):1053-1061
Red spruce (Picea rubens Sarg.) trees are uniquely vulnerable to foliar freezing injury during the cold season (fall and winter), but are also capable
of photosynthetic activity if temperatures moderate. To evaluate the influence of calcium (Ca) addition on the physiology
of red spruce during the cold season, we measured concentrations of foliar polyamines and free amino acids (putative stress-protection
compounds), chlorophyll (a key photosystem component), and sapwood area (a proxy for foliar biomass), for trees in Ca-addition
(CaSiO3 added) and Ca-depleted (reference) watersheds at the Hubbard Brook Experimental Forest (NH, USA). Ca-addition increased concentrations
of the amino acids alanine and γ-aminobutyric acid (GABA) and the polyamines putrescine (Put) and spermidine (Spd) in November,
and Put in February relative to foliage from the reference watershed. Consistent with increased stress protection, foliage
from the Ca-addition watershed had higher total chlorophyll and chlorophyll a concentrations in February than foliage from the reference watershed. In contrast, foliage from the reference watershed had
significantly lower glutamic acid (Glu) and higher alanine (Ala) concentrations in February than foliage from the Ca-addition
watershed. Imbalances in Ala:Glu have been attributed to cold sensitivity or damage in other species. In addition to concentration-based
differences in foliar compounds, trees from the Ca-addition watershed had higher estimated levels of foliar biomass than trees
from the reference watershed. Our findings suggest that Ca-addition increased the stress tolerance and productive capacity
of red spruce foliage during the cold season, and resulted in greater crown mass compared to trees growing on untreated soils. 相似文献
942.
943.
While our understanding of gene-based biology has greatly improved, it is clear that the function of the genome and most diseases cannot be fully explained by genes and other regulatory elements. Genes and the genome represent distinct levels of genetic organization with their own coding systems; Genes code parts like protein and RNA, but the genome codes the structure of genetic networks, which are defined by the whole set of genes, chromosomes and their topological interactions within a cell. Accordingly, the genetic code of DNA offers limited understanding of genome functions. In this perspective, we introduce the genome theory which calls for the departure of gene-centric genomic research. To make this transition for the next phase of genomic research, it is essential to acknowledge the importance of new genome-based biological concepts and to establish new technology platforms to decode the genome beyond sequencing. 相似文献
944.
Parthiban P Pallela R Kim SK Park DH Jeong YT 《Bioorganic & medicinal chemistry letters》2011,21(22):6678-6686
A series of twenty 2,6-diarylpiperidin-4-one O-methyloximes were synthesized with fluoro/chloro/bromo/methyl/methoxy/ethoxy/isopropyl substituents on various positions of the phenyl at C-2 and C-6 in association with/without methyl substituent on the secondary amino group and methyl/ethyl/isopropyl substituents on the active methylene centers. Regardless of their substitution all compounds predominantly exist in the chair conformation except 3m, which adopts a twist-boat conformation. All the synthesized compounds were evaluated for their in vitro antiproliferative activity against human cervical carcinoma (HeLa) cell line. The cytotoxicity of the test compounds was determined by measuring the number of live cells after 24 h of treatment by MTT assay method. This preliminary SAR suggests some lead molecules 3c-f, 3j-k, 4d-g, and 4i with a scope of further structural optimization of the piperidone pharmacophore toward the development of anticancer drug synthesis. 相似文献
945.
Our recent study has shown that ubiquinol-cytochrome c reductase binding protein (UQCRB), the 13.4-kDa subunit of mitochondrial complex III, plays a crucial role in hypoxia-induced angiogenesis via mitochondrial reactive oxygen species (ROS)-mediated signaling. Here we report a new synthetic small molecule targeting the mitochondrial oxygen sensor UQCRB that was identified by pharmacophore-based virtual screening and in vitro and in vivo competition binding analyses. 6-((1-Hydroxynaphthalen-4-ylamino)dioxysulfone)-2H-naphtho[1,8-bc]thiophen-2-one (HDNT) binds to the hydrophobic pocket of UQCRB and potently inhibits in vitro angiogenesis of human umbilical vein endothelial cells without cytotoxicity. Furthermore, the binding of HDNT to UQCRB suppressed mitochondrial ROS-mediated hypoxic signal transduction. These results demonstrated that HDNT is a novel synthetic small molecule targeting UQCRB and exhibits anti-angiogenic activity by modulating the oxygen-sensing function of UQCRB. 相似文献
946.
The continual destruction and renewal of proteins that maintain cellular homeostasis has been rigorously studied since the late 1930s. Experimental techniques for measuring protein turnover have evolved to measure the dynamic regulation of key proteins and now, entire proteomes. In the past decade, the proteomics field has aimed to discover how cells adjust their proteomes to execute numerous regulatory programs in response to specific cellular and environmental cues. By combining classical biochemical techniques with modern, high-throughput technologies, researchers have begun to reveal the synthesis and degradation mechanisms that shape protein turnover on a global scale. This review examines several recent developments in protein turnover research, emphasizing the combination of metabolic labeling and mass spectrometry. 相似文献
947.
948.
949.
Park JY Jeong HJ Kim YM Park SJ Rho MC Park KH Ryu YB Lee WS 《Bioorganic & medicinal chemistry letters》2011,21(18):5602-5604
As part of our ongoing effort to develop influenza virus neuraminidase (NA) inhibitors from various medicinal plants, we utilized bioassay-guided fractionation to isolated six alkylated chalcones (1-6) from Angelica keiskei. Xanthokeistal A (1) emerged as new compound containing the rare alkyl substitution, 6,6-dimethoxy-3-methylhex-2-enyl. When we tested the ability of these individual alkyl substituted chalcones to inhibit influenza virus NA hydrolysis, we found that 2-hydroxy-3-methyl-3-butenyl alkyl (HMB) substituted chalcone (3, IC(50)=12.3 μM) showed most potent inhibitory activity. The order of potency of substituted alkyl groups on for NA inhibition was HMB>6-hydroxyl-3,7-dimethyl-octa-2,7-dienyl>dimethylallyl>geranyl. All NA inhibitors screened were found to be reversible noncompetitive inhibitors. 相似文献
950.
Arumugam S Chin J Schirrmacher R Popik VV Kostikov AP 《Bioorganic & medicinal chemistry letters》2011,21(23):6987-6991
N-Terminally azido-modified peptides were labeled with the novel prosthetic labeling synthon [(18)F]azadibenzocyclooctyne ([(18)F]ADIBO) using copper-free azide-alkyne [3+2]-dipolar cycloaddition in high radiochemical yields (RCYs). (18)F-Labeled [(18)F]ADIBO was prepared by nucleophilic substitution of the corresponding tosylate in 21% overall RCY (EOB) in a fully automated synthesis unit within 55 min. [(18)F]ADIBO was incubated with azide-containing peptides at room temperature in the absence of toxic metal catalysts and the formation of the triazole conjugate was confirmed. Finally, the azide-alkyne [3+2]-dipolar cycloaddition was shown to proceed with 95% radiochemical yield in ethanol within 30 min, allowing for a development of a kit-like peptide labeling approach with [(18)F]ADIBO. 相似文献