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排序方式: 共有329条查询结果,搜索用时 15 毫秒
271.
Stefanie Döll Markus Kuhlmann Twan Rutten Michael F. Mette Sarah Scharfenberg Antonios Petridis Dorothee‐Carina Berreth Hans‐Peter Mock 《The Plant journal : for cell and molecular biology》2018,93(3):431-444
Secondary metabolites are involved in the plant stress response. Among these are scopolin and its active form scopoletin, which are coumarin derivatives associated with reactive oxygen species scavenging and pathogen defence. Here we show that scopolin accumulation can be induced in the root by osmotic stress and in the leaf by low‐temperature stress in Arabidopsis thaliana. A genetic screen for altered scopolin levels in A. thaliana revealed a mutant compromised in scopolin accumulation in response to stress; the lesion was present in a homologue of THO1 coding for a subunit of the THO/TREX complex. The THO/TREX complex contributes to RNA silencing, supposedly by trafficking precursors of small RNAs. Mutants defective in THO, AGO1, SDS3 and RDR6 were impaired with respect to scopolin accumulation in response to stress, suggesting a mechanism based on RNA silencing such as the trans‐acting small interfering RNA pathway, which requires THO/TREX function. 相似文献
272.
Investigation on Toxicity and Teratogenicity in Rats of a Retinoid‐Polyamine Conjugate with Potent Anti‐Inflammatory Properties 下载免费PDF全文
Theodoros Petridis Dimitra Giannakopoulou Vassiliki Stamatopoulou Katerina Grafanaki Christos G. Kostopoulos Helen Papadaki Nikos K. Karamanos Stathianna Douroumi Dionysios Papachristou George E. Magoulas Dionissios Papaioannou Denis Drainas 《Birth defects research. Part B, Developmental and reproductive toxicology》2016,107(1):32-44
Previous studies have shown that N1,N12‐bis(all‐trans‐retinoyl)spermine (RASP), a retinoid analog, inhibits RNase P activity and angiogenesis in the chicken embryo chorioallantoic membrane, demonstrates anti‐tumor activity on prostate cancer cells, and acts as anti‐inflammatory agent, being more effective and less toxic than all‐trans retinoic acid. In an attempt to further characterize the biological profile of RASP, we tested its effects on organ toxicity and teratogenicity by daily oral gavage of RASP at a level of 50 mg/Kg of body weight in two generations of rats. We found that this compound does not induce changes to the body growth, the appearance of physical features, and the animal's reflexes. Additionally, no substantial histopathological lesions were found in brain, heart, lung, thymus, liver, thyroid gland, adrenal gland, pituitary gland, kidneys, spleen, skin, femora, prostate, testis, epididymis, vagina, uterus, and ovaries of RASP‐treated animals. These results suggest RASP, as a promising lead compound for the treatment of several dermatological disorders and certain cancer types, has apparently minimal toxic side‐effects as revealed in this two‐generation reproduction study in rats. 相似文献
273.
274.
Tataridis D Fytas G Kolocouris A Fytas C Kolocouris N Foscolos GB Padalko E Neyts J De Clercq E 《Bioorganic & medicinal chemistry letters》2007,17(3):692-696
We examined whether the incorporation of a second amino group into the 1-aminoethyl pharmacophore of rimantadine 2 and into the piperidine pharmacophore of the heterocyclic rimantadine 4 was compatible with anti-influenza virus A activity. The new synthetic molecules are capable of forming two hydrogen bonds within the receptor. We identified molecules 8 and 16, bearing the adamantyl and 1,2-diaminoethyl groups, which are equipotent to rimantadine 2 bearing the adamantyl and 1-aminoethyl pharmacophore groups. Interestingly, diamino compound 16 is a 4-fold more potent inhibitor than its parent monoamino heterocyclic rimantadine 4 propably because of additional hydrogen bonding interactions with the M2 protein receptor. 相似文献
275.
Raj DS Adeniyi O Dominic EA Boivin MA McClelland S Tzamaloukas AH Morgan N Gonzales L Wolfe R Ferrando A 《American journal of physiology. Endocrinology and metabolism》2007,292(6):E1534-E1542
Intradialytic protein catabolism is attributed to loss of amino acids in the dialysate. We investigated the effect of amino acid infusion during hemodialysis (HD) on muscle protein turnover and amino acid transport kinetics by using stable isotopes of phenylalanine, leucine, and lysine in eight patients with end-stage renal disease (ESRD). Subjects were studied at baseline (pre-HD), 2 h of HD without amino acid infusion (HD-O), and 2 h of HD with amino acid infusion (HD+AA). Amino acid depletion during HD-O augmented the outward transport of amino acids from muscle into the vein. Increased delivery of amino acids to the leg during HD+AA facilitated the transport of amino acids from the artery into the intracellular compartment. Increase in muscle protein breakdown was more than the increase in synthesis during HD-O (46.7 vs. 22.3%, P < 0.001). Net balance (nmol.min(-1).100 ml (-1)) was more negative during HD-O compared with pre-HD (-33.7 +/- 1.5 vs. -6.0 +/- 2.3, P < 0.001). Despite an abundant supply of amino acids, the net balance (-16.9 +/- 1.8) did not switch from net release to net uptake. HD+AA induced a proportional increase in muscle protein synthesis and catabolism. Branched chain amino acid catabolism increased significantly from baseline during HD-O and did not decrease during HD+AA. Protein synthesis efficiency, the fraction of amino acid in the intracellular pool that is utilized for muscle protein synthesis decreased from 42.1% pre-HD to 33.7 and 32.6% during HD-O and HD+AA, respectively (P < 0.01). Thus amino acid repletion during HD increased muscle protein synthesis but did not decrease muscle protein breakdown. 相似文献
276.
This protocol describes the synthesis of poly(L-lactide) by ring-opening polymerization of L-lactide using tin(II) 2-ethylhexanoate catalyst as well as the synthesis of polyglycolide by ring-opening polymerization of glycolide. Ring-opening polymerization of cyclic diesters synthesized from alpha-hydroxycarboxylic acids gives high-molecular-weight polyester in high yield. Tin(II) 2-ethylhexanoate catalyst is the most common catalyst for ring-opening polymerization of diesters owing to its high reactivity and low toxicity. Purity of monomers and the amount of water and alcohol in the reaction system are significant factors for increasing molecular weight and conversion of polyesters. The molecular weight of the polyesters is also dependent on reaction temperature and reaction time. This protocol can be completed in 3 d for the synthesis of poly(L-lactide) and 2 d for the synthesis of polyglycolide. 相似文献
277.
Old yellow enzymes, highly homologous FMN oxidoreductases with modulating roles in oxidative stress and programmed cell death in yeast 总被引:1,自引:0,他引:1
Odat O Matta S Khalil H Kampranis SC Pfau R Tsichlis PN Makris AM 《The Journal of biological chemistry》2007,282(49):36010-36023
In a genetic screen to identify modifiers of Bax-dependent lethality in yeast, the C terminus of OYE2 was isolated based on its capacity to restore sensitivity to a Bax-resistant yeast mutant strain. Overexpression of full-length OYE2 suppresses Bax lethality in yeast, lowers endogenous reactive oxygen species (ROS), increases resistance to H(2)O(2)-induced programmed cell death (PCD), and significantly lowers ROS levels generated by organic prooxidants. Reciprocally, Delta oye2 yeast strains are sensitive to prooxidant-induced PCD. Overexpression and knock-out analysis indicate these OYE2 antioxidant activities are opposed by OYE3, a highly homologous heterodimerizing protein, which functions as a prooxidant promoting H(2)O(2)-induced PCD in wild type yeast. To exert its effect OYE3 requires the presence of OYE2. Deletion of the 12 C-terminal amino acids and catalytic inactivation of OYE2 by a Y197F mutation enhance significantly survival upon H(2)O(2)-induced PCD in wild type cells, but accelerate PCD in Delta oye3 cells, implicating the oye2p-oye3p heterodimer for promoting cell death upon oxidative stress. Unexpectedly, a strain with a double knock-out of these genes (Delta oye2 oye3) is highly resistant to H(2)O(2)-induced PCD, exhibits increased respiratory capacity, and undergoes less cell death during the adaptive response in chronological aging. Simultaneous deletion of OYE2 and other antioxidant genes hyperinduces endogenous levels of ROS, promoting H(2)O(2)-induced cell death: in Delta oye2 glr1 yeast high levels of oxidized glutathione elicited gross morphological aberrations involving the actin cytoskeleton and defects in organelle partitioning. Altering the ratio of reduced to oxidized glutathione by exogenous addition of GSH fully reversed these alterations. Based on this work, OYE proteins are firmly placed in the signaling network connecting ROS generation, PCD modulation, and cytoskeletal dynamics in yeast. 相似文献
278.
Arthur A. D. Broadbent Michael Bahn William J. Pritchard Lindsay K. Newbold Tim Goodall Andrew Guinta Helen S. K. Snell Irene Cordero Antonios Michas Helen K. Grant David X. Soto Rüdiger Kaufmann Michael Schloter Robert I. Griffiths Richard D. Bardgett 《Ecology letters》2022,25(1):52-64
Climate change is disproportionately impacting mountain ecosystems, leading to large reductions in winter snow cover, earlier spring snowmelt and widespread shrub expansion into alpine grasslands. Yet, the combined effects of shrub expansion and changing snow conditions on abiotic and biotic soil properties remains poorly understood. We used complementary field experiments to show that reduced snow cover and earlier snowmelt have effects on soil microbial communities and functioning that persist into summer. However, ericaceous shrub expansion modulates a number of these impacts and has stronger belowground effects than changing snow conditions. Ericaceous shrub expansion did not alter snow depth or snowmelt timing but did increase the abundance of ericoid mycorrhizal fungi and oligotrophic bacteria, which was linked to decreased soil respiration and nitrogen availability. Our findings suggest that changing winter snow conditions have cross-seasonal impacts on soil properties, but shifts in vegetation can modulate belowground effects of future alpine climate change. 相似文献
279.
Athanasios Kossyvakis Ying Tao Xiaoyan Lu Vasiliki Pogka Sotirios Tsiodras Mary Emmanouil Andreas F. Mentis Suxiang Tong Dean D. Erdman Antonios Antoniadis 《PloS one》2015,10(4)
Rapid and reliable laboratory diagnosis of persons suspected of Middle East respiratory syndrome coronavirus (MERS-CoV) infection is important for timely implementation of infection control practices and disease management. In addition, monitoring molecular changes in the virus can help elucidate chains of transmission and identify mutations that might influence virus transmission efficiency. This was illustrated by a recent laboratory investigation we conducted on an imported MERS-CoV case in Greece. Two oropharyngeal swab specimens were collected on the 1st and 2nd day of patient hospitalization and tested using two real-time RT-PCR (rRT-PCR) assays targeting the UpE and Orf-1a regions of the MERS-CoV genome and RT-PCR and partial sequencing of RNA-dependent RNA polymerase and nucleocapsid genes. Serum specimens were also collected and serological test were performed. Results from the first swab sample were inconclusive while the second swab was strongly positive for MERS-CoV RNA by rRT-PCR and confirmed positive by RT-PCR and partial gene sequencing. Positive serologic test results further confirmed MERS-CoV infection. Full-length nucleocapsid and spike gene coding sequences were later obtained from the positive swab sample. Phylogenetic analysis revealed that the virus was closely related to recent human-derived MERS-CoV strains obtained in Jeddah and Makkah, Saudi Arabia, in April 2014 and dromedary camels in Saudi Arabia and Qatar. These findings were consistent with the patient’s history. We also identified a unique amino acid substitution in the spike receptor binding domain that may have implications for receptor binding efficiency. Our initial inconclusive rRT-PCR results highlight the importance of collecting multiple specimens from suspect MERS-CoV cases and particularly specimens from the lower respiratory tract. 相似文献
280.
Dragana Bo?i? Dimitra Papaefthimiou Kathleen Brückner Ric C. H. de Vos Constantinos A. Tsoleridis Dimitra Katsarou Antigoni Papanikolaou Irini Pateraki Fani M. Chatzopoulou Eleni Dimitriadou Stefanos Kostas David Manzano Ulschan Scheler Albert Ferrer Alain Tissier Antonios M. Makris Sotirios C. Kampranis Angelos K. Kanellis 《PloS one》2015,10(5)