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排序方式: 共有441条查询结果,搜索用时 15 毫秒
71.
Massah AR Adibi H Khodarahmi R Abiri R Majnooni MB Shahidi S Asadi B Mehrabi M Zolfigol MA 《Bioorganic & medicinal chemistry》2008,16(10):5465-5472
Silica sulfuric acid catalyzes efficiently the reaction of sulfonamides with both carboxylic acid anhydrides and chlorides under solvent-free and heterogeneous conditions. All the reactions were done at room temperature and the N-acylsulfonamides were obtained with high yields and purity via an easy work-up procedure. This method is attractive and is in a close agreement with green chemistry. These compounds were also investigated for antibacterial activity, including Gram-positive cocci and Gram-negative bacilli, and carbonic anhydrase II inhibitory activity. 相似文献
72.
Heidari MM Houshmand M Hosseinkhani S Nafissi S Scheiber-Mojdehkar B Khatami M 《Cellular and molecular neurobiology》2009,29(2):225-233
Friedreich’s ataxia (FRDA) is an autosomal recessive neurodegenerative disorder caused by decreased expression of the protein
Frataxin. Frataxin deficiency leads to excessive free radical production and dysfunction of chain complexes. Mitochondrial
DNA (mtDNA) could be considered a candidate modifier factor for FRDA disease, since mitochondrial oxidative stress is thought
to be involved in the pathogenesis of this disease. It prompted us to focus on the mtDNA and monitor the nucleotide changes
of genome which are probably the cause of respiratory chain defects and reduced ATP generation. We searched about 46% of the
entire mitochondrial genome by temporal temperature gradient gel electrophoresis (TTGE) and DNA fragments showing abnormal
banding patterns were sequenced for the identification of exact mutations. In 18 patients, for the first time, we detected
26 mtDNA mutations; of which 5 (19.2%) was novel and 21 (80.8%) have been reported in other diseases. Heteroplasmic C13806A
polymorphisms were associated with Iranian FRDA patients (55.5%). Our results showed that NADH dehydrogenase (ND) genes mutations
in FRDA samples were higher than normal controls (P < 0.001) and we found statistically significant inverse correlation (r = −0.8) between number of mutation in ND genes and age of onset in FRDA patients. It is possible that mutations in ND genes
could constitute a predisposing factor which in combination with environmental risk factors affects age of onset and disease
progression. 相似文献
73.
Timothy P. Shiau Ashley Houchin Satheesh Nair Ping Xu Eddy Low Ramin Najafi Rakesh Jain 《Bioorganic & medicinal chemistry letters》2009,19(4):1110-1114
New topical anti-infectives comprised of N,N-dichloro-β,β-disubstituted taurines [Tetrahedron Lett. 2008, 49, 2193; Biorg. Med. Chem. Lett. 2009, 19, 196] have been examined for structure–stability relationships (SSR) based upon various alkyl, heteroalkyl and cycloalkyl β-substitutions. These substitutions affect order-of-magnitude changes in the aqueous stability of these N,N-dichloroamines which can undergo Stieglitz rearrangement of alkyl groups under extremely mild conditions (H2O, pH 4–7, 0–20 mM acetate or phosphate buffer, 20–40 °C). This process produces β-ketosulfonic acids which function as substrates for chlorination by the N-chlorotaurines which leads to their further degradation. 相似文献
74.
Kumar JS Majo VJ Sullivan GM Prabhakaran J Simpson NR Van Heertum RL Mann JJ Parsey RV 《Bioorganic & medicinal chemistry》2006,14(12):4029-4034
Synthesis and evaluation of [O-methyl-11C](4-methoxy-2-methylphenyl)[1-(1-methoxymethylpropyl)-6-methyl-1H-[1,2,3]triazolo[4,5-c]pyridin-4-yl]amine or [11C]SN003 ([11C]6), as a PET imaging agent for CRF1 receptors, in baboons is described. 4-[1-(1-Methoxymethylpropyl)-6-methyl-1H-[1,2,3]triazolo[4,5-c]pyridin-4-ylamino]-3-methylphenol (5), the precursor molecule for the radiolabeling, was synthesized from 2,4-dichloro-6-methyl-3-nitropyridine in seven steps with 20% overall yield. The total time required for the synthesis of [11C]SN003 is 30 min from EOB using [11C]methyl triflate in the presence of NaOH in acetone. The yield of the synthesis is 22% (EOS) with >99% chemical and radiochemical purities and a specific activity of >2000 Ci/mmol. PET studies in baboon show that [11C]6 penetrates the BBB and accumulates in brain. No detectable specific binding was observed, likely due to the rapid metabolism or low density of CRF1 receptors in primate brain. 相似文献
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77.
Astaxanthin is a carotenoid pigment responsible for the red color of the flesh of many marine animals. There is an increasing interest in the use of astaxanthin in aquaculture, chemical, pharmaceutical, and alimentary industries. Phaffia rhodozyma has been identified as the best biological source of astaxanthin. Mutagenesis was carried out using different doses of gamma irradiation (1.0, 2.0, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, and 7.0 kGy), and 10 mutant colonies (Gam1-Gam10) were obtained. Highly pigmented mutant strains produced astaxanthin at approximately 15?887.5?μg/L dry mass of yeast, whereas the parental strain produced it at 1061.64?μg/g dry mass of yeast. In the thin-layer chromatography analysis, P. rhodozyma JH-82 and Gam1 mutant strain produced the same retention factor (R(f)) values, but Gam1 showed a higher astaxanthin content than JH-82. 相似文献
78.
Drews GN Wang D Steffen JG Schumaker KS Yadegari R 《Journal of experimental botany》2011,62(5):1593-1599
Until recently, identification of gene regulatory networks controlling the development of the angiosperm female gametophyte has presented a significant challenge to the plant biology community. The angiosperm female gametophyte is fairly inaccessible because it is a highly reduced structure relative to the sporophyte and is embedded within multiple layers of the sporophytic tissue of the ovule. Moreover, although mutations affecting the female gametophyte can be readily isolated, their analysis can be difficult because most affect genes involved in basic cellular processes that are also required in the diploid sporophyte. In recent years, expression-based approaches in multiple species have begun to uncover gene sets expressed in specific female gametophyte cells as a means of identifying regulatory networks controlling cell differentiation in the female gametophyte. Here, recent efforts to identify and analyse gene expression programmes in the Arabidopsis female gametophyte are reviewed. 相似文献
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