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121.
Hao Wu Lei Sun Fabian Blombach Stan J.J. Brouns Ambrosius P. L. Snijders Kristina Lorenzen Robert H. H. van den Heuvel Albert J. R. Heck Sheng Fu Xuemei Li Xuejun C. Zhang Zihe Rao John van der Oost 《Proteins》2010,78(3):705-713
The HflX‐family is a widely distributed but poorly characterized family of translation factor‐related guanosine triphosphatases (GTPases) that interact with the large ribosomal subunit. This study describes the crystal structure of HflX from Sulfolobus solfataricus solved to 2.0‐Å resolution in apo‐ and GDP‐bound forms. The enzyme displays a two‐domain architecture with a novel “HflX domain” at the N‐terminus, and a classical G‐domain at the C‐terminus. The HflX domain is composed of a four‐stranded parallel β‐sheet flanked by two α‐helices on either side, and an anti‐parallel coiled coil of two long α‐helices that lead to the G‐domain. The cleft between the two domains accommodates the nucleotide binding site as well as the switch II region, which mediates interactions between the two domains. Conformational changes of the switch regions are therefore anticipated to reposition the HflX‐domain upon GTP‐binding. Slow GTPase activity has been confirmed, with an HflX domain deletion mutant exhibiting a 24‐fold enhanced turnover rate, suggesting a regulatory role for the HflX domain. The conserved positively charged surface patches of the HflX‐domain may mediate interaction with the large ribosomal subunit. The present study provides a structural basis to uncover the functional role of this GTPases family whose function is largely unknown. Proteins 2010. © 2009 Wiley‐Liss, Inc. 相似文献
122.
Amy C. Schroeder Chuanmei Zhu Srinivasa Rao Yanamadala Rebecca E. Cahoon Kiani A. J. Arkus Leia Wachsstock Jeremy Bleeke Hari B. Krishnan Joseph M. Jez 《The Journal of biological chemistry》2010,285(2):827-834
Aspartate kinase (AK) and homoserine dehydrogenase (HSD) function as key regulatory enzymes at branch points in the aspartate amino acid pathway and are feedback-inhibited by threonine. In plants the biochemical features of AK and bifunctional AK-HSD enzymes have been characterized, but the molecular properties of the monofunctional HSD remain unexamined. To investigate the role of HSD, we have cloned the cDNA and gene encoding the monofunctional HSD (GmHSD) from soybean. Using heterologously expressed and purified GmHSD, initial velocity and product inhibition studies support an ordered bi bi kinetic mechanism in which nicotinamide cofactor binds first and leaves last in the reaction sequence. Threonine inhibition of GmHSD occurs at concentrations (Ki = 160–240 mm) more than 1000-fold above physiological levels. This is in contrast to the two AK-HSD isoforms in soybean that are sensitive to threonine inhibition (Ki∼150 μm). In addition, GmHSD is not inhibited by other aspartate-derived amino acids. The ratio of threonine-resistant to threonine-sensitive HSD activity in soybean tissues varies and likely reflects different demands for amino acid biosynthesis. This is the first cloning and detailed biochemical characterization of a monofunctional feedback-insensitive HSD from any plant. Threonine-resistant HSD offers a useful biotechnology tool for manipulating the aspartate amino acid pathway to increase threonine and methionine production in plants for improved nutritional content. 相似文献
123.
Cleome viscosa, an annual herb locally known as Jakhiya, grows naturally from seed in rainfed agricultural land and abandoned crop fields at altitudes ranging from 500 to 1500 m in scattered pockets of the Garhwal Himalaya. The seeds are mostly used as condiment. This species is a good substitute of cumin (Cuminum cyminum). Traditionally it is also used to cure a variety of diseases. It provides, three times higher yield when maintained by the farmers as a pure crop compared to yield obtained in mixed cropping conditions. With other food commodities, it is exchanged by the traditional farmers of Garhwal with the people of the areas where it does not grow. Because of its increasing demand, it is being sold in the market and is gaining more and more popularity. Until now no systematic attempt has been made to study the ecological significance and economic potential of Cleome viscosa. This paper describes the agronomy, yield, cost-benefit analysis, uses, and ethnobotany of Cleome viscosa. Systematic efforts are needed to promote its cultivation on a larger scale in village community degraded land and in marginal agricultural land where traditional crops grow with difficulty. 相似文献
124.
Suryanaryana Murty Upadhyayula Srinivasa Rao Mutheneni Sumana Chenna Vaideesh Parasaram Madhusudhan Rao Kadiri 《PloS one》2015,10(3)
The present study was conducted during the years 2006 to 2012 and provides information on prevalence of malaria and its regulation with effect to various climatic factors in East Siang district of Arunachal Pradesh, India. Correlation analysis, Principal Component Analysis and Hotelling’s T2 statistics models are adopted to understand the effect of weather variables on malaria transmission. The epidemiological study shows that the prevalence of malaria is mostly caused by the parasite Plasmodium vivax followed by Plasmodium falciparum. It is noted that, the intensity of malaria cases declined gradually from the year 2006 to 2012. The transmission of malaria observed was more during the rainy season, as compared to summer and winter seasons. Further, the data analysis study with Principal Component Analysis and Hotelling’s T2 statistic has revealed that the climatic variables such as temperature and rainfall are the most influencing factors for the high rate of malaria transmission in East Siang district of Arunachal Pradesh. 相似文献
125.
K. Sankara Rao 《Plant cell reports》1986,5(3):199-201
Callus-mediated shoot bud formation was demonstrated in Dalbergia latifolia Roxb. (East Indian Rosewood). Cultures were raised from shoot explants of six year-old plants on Murashige and Skoog (MS) medium supplemented with naphthaleneacetic acid (NAA) and benzyladenine (BA). A sequential treatment of callus with increasing BA levels and decreasing NAA ensured shoot bud induction. Rooting of shoots was achieved by a three-step culture procedure involving 1) White's(W) liquid medium containing indoleacetic acid (IAA), naphthaleneacetic acid and indolebutyric acid (IBA), 2) half-strength MS agar-solidified medium with charcoal (0.25%) and 3) half-strength MS liquid medium.Abbreviations BA
Benzyladenine
- IAA
Indoleacetic acid
- IBA
Indolebutyric acid
- MS
Murashige and Skoog
- NAA
a-naphthaleneacetic acid
- PVP
Polyvinylpyrrolidone
- W
White's medium
- 2,4-D
2,4-dichlorophenoxyacetic acid 相似文献
126.
Vasudeva Rao Avupati Rajendra Prasad Yejella Venkateswara Rao Parala Kishore Naidu Killari Venkata Madhava Reddy Papasani Prasad Cheepurupalli Venkateswara Rao Gavalapu Bhavani Boddeda 《Bioorganic & medicinal chemistry letters》2013,23(21):5968-5970
A series of some novel 1,3,5-triazine–Schiff base conjugates (1–32) have been synthesized and evaluated for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv using Alamar Blue assay and the activity expressed as the minimum inhibitory concentration (MIC) in μg/mL. Compounds 4 (4-Methoxy-6-methyl-N-(3,4,5-trimethoxybenzylidene)-1,3,5-triazin-2-amine), 11 (4-Methoxy-6-methyl-N-(2-hydroxy-3-bromo-5-chloro-benzylidene)-1,3,5-triazin-2-amine) and 24 (4-Methoxy-6-methyl-N-(1-(2,5-dihydroxyphenyl)ethylidene)-1,3,5-triazin-2-amine) exhibited a significant activity at 3.125, 6.25 and 6.25 μg/mL, respectively, when compared with the antitubercular drugs such as ethambutol (3.125 μg/mL), pyrazinamide (6.25 μg/mL) and streptomycin (6.25 μg/mL) and it could be a potential starting point to develop new lead compounds in the fight against Mycobacterium tuberculosis H37Rv. 相似文献
127.
Anuj K. Chandel M. Lakshmi Narasu G. Chandrasekhar A. Manikyam L. Venkateswar Rao 《Bioresource technology》2009,100(8):2404-2410
Saccharum spontaneum is a wasteland weed consists of 45.10 ± 0.35% cellulose and 22.75 ± 0.28% of hemicellulose on dry solid (DS) basis. Aqueous ammonia delignified S. spontaneum yielded total reducing sugars, 53.91 ± 0.44 g/L (539.10 ± 0.55 mg/g of substrate) with a hydrolytic efficiency of 77.85 ± 0.45%. The enzymes required for hydrolysis were prepared from culture supernatants of Aspergillus oryzae MTCC 1846. A maximum of 0.85 ± 0.07 IU/mL of filter paperase (FPase), 1.25 ± 0.04 IU/mL of carboxy methyl cellulase (CMCase) and 55.56 ± 0.52 IU/mL of xylanase activity was obtained after 7 days of incubation at 28 ± 0.5 °C using delignified S. spontaneum as carbon source under submerged fermentation conditions. Enzymatic hydrolysate of S. spontaneum was then tested for ethanol production under batch and repeated batch production system using “in-situ” entrapped Saccharomyces cerevisiae VS3 cells in S. spontaneum stalks (1 cm × 1 cm) size. Immobilization was confirmed by the scanning electron microscopy (SEM). Batch fermentation of VS3 free cells and immobilized cells showed ethanol production, 19.45 ± 0.55 g/L (yield, 0.410 ± 0.010 g/g) and 21.66 ± 0.62 g/L (yield, 0.434 ± 0.021 g/g), respectively. Immobilized VS3 cells showed maximum ethanol production (22.85 ± 0.44 g/L, yield, 0.45 ± 0.04 g/g) up to 8th cycle during repeated batch fermentation followed by a gradual reduction in subsequent cycles of fermentation. 相似文献
128.
Enhanced plant regeneration in grain and sweet sorghum by asparagine,proline and cefotaxime 总被引:7,自引:0,他引:7
Summary Cefotaxime ( 50 and 100 mg/1 ), a cephalosporin antibiotic and the amino acids asparagine and proline (200 mg/l) enhanced the production of embryogenic callus, increased the frequency of plant regeneration, and delayed the loss of regeneration potential in immature embryo-derived callus cultures ofSorghum bicolor (L.) Moench. Although these compounds did not promote callus induction or growth of callus, they influenced plant regeneration considerably in 10 low responding genotypes of grain and high anthocyanin containing sweet sorghums. 相似文献
129.
Srinubabu G Patel RS Shedbalkar VP Rao AA Rao MN Bandaru VV 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2007,860(2):202-208
As a continuation of effort to improve our high flow on-line bioanalytical approach for high-throughput quantification of drugs and metabolites in plasma by high-throughput liquid chromatography tandem mass spectrometry (HTLC-MS/MS), we have developed a simple, sensitive and reliable method for simultaneous quantification of loratadine and desloratadine in human plasma. We have performed on-line coupling of extraction with Cyclone P 50 mm x 0.5 mm 50 microm HTLC column and chromatographic separation is performed with Zorbax XDB C18 50 mm x 2.1 mm 5 microm, followed by quantification with mass detector. The method is validated and showed good performances in terms of linearity, sensitivity, precision, accuracy and stability. A marked improvement in sample throughput efficiency is realized with this method and the proposed method will be useful for pharmacokinetic and/or bioequivalence studies. 相似文献
130.
LC-MS/MS determination of helicid in human plasma and its application in pharmacokinetic studies 总被引:1,自引:0,他引:1
Xie H Jia Y Tan Z Zhang W Chen R Sun H Shen J Zhou H 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2011,879(30):3607-3611
Helicid is a traditional Chinese medicine used to treat headache and insomnia with definite effects. To facilitate pharmacokinetic studies of helicid in man, a sensitive and specific LC-MS/MS method for the quantitative detection of helicid in human plasma was developed and validated. The method involved the addition of bergeninum as the internal standard (IS), protein precipitation, HPLC separation, and quantification by MS/MS system using negative electrospray ionization in the multiple reaction monitoring mode (MRM). The precursor→product ion transitions were monitored at m/z 282.8→120.9 for helicid and m/z 326.9→192.2 for the IS, respectively. The lower limit of quantification (LLOQ) was 0.2 μg/L. The calibration curves for helicid was linear over a concentration range of 0.2-20 μg/L. The intra- and inter-batch analyses of QC samples at 0.4, 2, 20 μg/L indicated good precision (%R.S.D. between 2.69 and 5.47%) and accuracy (between 96.15 and 105.05%). The helicid was stable in human plasma stored at room temperature for at least 24h, 4°C for at least 24h, -20°C for at least 1 month, and for routine three freeze-thaw cycles. This accurate and specific assay provides a useful method for evaluating the pharmacokinetic profile of helicid in humans. 相似文献