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181.
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183.
Jongho Sun J. Benjamin Miller Emma Granqvist Audrey Wiley-Kalil Enrico Gobbato Fabienne Maillet Sylvain Cottaz Eric Samain Muthusubramanian Venkateshwaran Sébastien Fort Richard J. Morris Jean-Michel Ané Jean Dénarié Giles E.D. Oldroyd 《The Plant cell》2015,27(3):823-838
Establishment of arbuscular mycorrhizal interactions involves plant recognition of diffusible signals from the fungus, including lipochitooligosaccharides (LCOs) and chitooligosaccharides (COs). Nitrogen-fixing rhizobial bacteria that associate with leguminous plants also signal to their hosts via LCOs, the so-called Nod factors. Here, we have assessed the induction of symbiotic signaling by the arbuscular mycorrhizal (Myc) fungal-produced LCOs and COs in legumes and rice (Oryza sativa). We show that Myc-LCOs and tetra-acetyl chitotetraose (CO4) activate the common symbiosis signaling pathway, with resultant calcium oscillations in root epidermal cells of Medicago truncatula and Lotus japonicus. The nature of the calcium oscillations is similar for LCOs produced by rhizobial bacteria and by mycorrhizal fungi; however, Myc-LCOs activate distinct gene expression. Calcium oscillations were activated in rice atrichoblasts by CO4, but not the Myc-LCOs, whereas a mix of CO4 and Myc-LCOs activated calcium oscillations in rice trichoblasts. In contrast, stimulation of lateral root emergence occurred following treatment with Myc-LCOs, but not CO4, in M. truncatula, whereas both Myc-LCOs and CO4 were active in rice. Our work indicates that legumes and non-legumes differ in their perception of Myc-LCO and CO signals, suggesting that different plant species respond to different components in the mix of signals produced by arbuscular mycorrhizal fungi. 相似文献
184.
185.
Steven M. Berry Erika L. Bladholm Elise J. Mostad Audrey R. Schenewerk 《Journal of biological inorganic chemistry》2011,16(3):473-480
Abstract
Loop-directed mutagenesis was applied to the blue copper protein azurin to replace its copper binding loop with that from the red copper protein nitrosocyanin. A ten amino acid long loop that provides three of the four copper ligands from nitrosocyanin was incorporated into azurin to make a variant called NC-azurin. The chimeric protein displayed a red color, and UV–vis absorption and EPR spectra that closely resembled those of the loop parent, nitrosocyanin. We added the fourth ligand from nitrosocyanin into NC-azurin, a carboxylate-containing amino acid, but the proteins had altered stability and spectroscopic properties that did not resemble those of either parent copper protein. The loop alone, however, was enough to impart red copper site characteristics to the NC-azurin protein. Finally, the reduction potential of the variant was found to be between the reduction potentials of the parent proteins and about 50 mV below that of wild-type azurin. 相似文献186.
Inge Everaert Antien Mooyaart Audrey Baguet Ana Zutinic Hans Baelde Eric Achten Youri Taes Emile De Heer Wim Derave 《Amino acids》2011,40(4):1221-1229
Carnosine is found in high concentrations in skeletal muscles, where it is involved in several physiological functions. The
muscle carnosine content measured within a population can vary by a factor 4. The aim of this study was to further characterize
suggested determinants of the muscle carnosine content (diet, gender and age) and to identify new determinants (plasma carnosinase
activity and testosterone). We investigated a group of 149 healthy subjects, which consisted of 94 men (12 vegetarians) and
55 women. Muscle carnosine was quantified in M. soleus, gastrocnemius and tibialis anterior using magnetic resonance proton
spectroscopy and blood samples were collected to determine CNDP1 genotype, plasma carnosinase activity and testosterone concentrations. Compared to women, men have 36, 28 and 82% higher
carnosine concentrations in M. soleus, gastrocnemius and tibialis anterior muscle, respectively, whereas circulating testosterone
concentrations were unrelated to muscle carnosine levels in healthy men. The carnosine content of the M. soleus is negatively
related to the subjects’ age. Vegetarians have a lower carnosine content of 26% in gastrocnemius compared to omnivores. In
contrast, there is no difference in muscle carnosine content between omnivores with a high or low ingestion of β-alanine.
Muscle carnosine levels are not related to the polymorphism of the CNDP1 gene or to the enzymatic activity of the plasma carnosinase. In conclusion, neither CNDP1 genotype nor the normal variation in circulating testosterone levels affects the muscular carnosine content, whereas vegetarianism,
female gender and increasing age are the factors associated with reduced muscle carnosine stores. 相似文献
187.
Johnson B Steadman R Patefield KD Bunker JJ Atkin AL Dussault P 《Bioorganic & medicinal chemistry letters》2011,21(8):2351-2353
A scalable four-step synthesis of the ornithine transcarbamylase inhibitor N5-phosphonoacetyl-l-ornithine (PALO) is achieved through boroxazolidinone protection of ornithine. Investigations in the model organism Saccharomyces cerevisiae found that, in contrast to a previous report, PALO did not influence growth rate or expression of genes involved in arginine metabolism. 相似文献
188.
Wang T Ioannidis S Almeida L Block MH Davies AM Lamb ML Scott DA Su M Zhang HJ Alimzhanov M Bebernitz G Bell K Zinda M 《Bioorganic & medicinal chemistry letters》2011,21(10):2958-2961
Synthesis and biological evaluation of a series of 6-aminopyrazolyl-pyridine-3-carbonitriles as JAK2 kinase inhibitors was reported. Biochemical screening, followed by profile optimization, resulted in JAK2 inhibitors exhibiting good kinase selectivity, pharmacokinetic properties, physical properties and pharmacodynamic effects. 相似文献
189.
190.
Lugari A Breuer S Coursindel T Opi S Restouin A Shi X Nazabal A Torbett BE Martinez J Collette Y Parrot I Arold ST Morelli X 《Bioorganic & medicinal chemistry》2011,19(24):7401-7406
The HIV-1 auxiliary protein Nef is required for the onset and progression of AIDS in HIV-1-infected persons. Here, we have deciphered the mode of action of a second-generation inhibitor of Nef, DLC27-14, presenting a competitive IC(50) of ~16 μM measured by MALDI-TOF experiments. Thermal protein denaturation experiments revealed a negative effect on stability of Nef in the presence of a saturating concentration of the inhibitor. The destabilizing action of DLC27-14 was confirmed by a HIV protease-based experiment, in which the protease sensitivity of DLC27-14-bound Nef was three times as high as that of apo Nef. The only compatible docking modes of action for DLC27-14 suggest that DLC27-14 promotes an opening of two α-helices that would destabilize the Nef core domain. DLC27-14 thus acts as a specific protein disorder catalyzer that destabilizes the folded conformation of the protein. Our results open novel avenues toward the development of next-generation Nef inhibitors. 相似文献