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931.
Alok Kumar Gupta Vikram Singh Gaur Sanjay Gupta Anil Kumar 《Functional & integrative genomics》2013,13(2):179-190
In order to understand the molecular basis of high nitrogen use efficiency of finger millet, five genes (EcHNRT2, EcLNRT1, EcNADH-NR, EcGS, and EcFd-GOGAT) involved in nitrate uptake and assimilation were isolated using conserved primer approaches. Expression profiles of these five genes along with the previously isolated EcDof1 was studied under increased KNO3 concentrations (0.15 to 1,500 μM) for 2 h as well as at 1.5 μM for 24 h in the roots and shoots of 25 days old nitrogen deprived two contrasting finger millet genotypes (GE-3885 and GE-1437) differing in grain protein content (13.76 and 6.15 %, respectively). Time kinetics experiment revealed that, all the five genes except EcHNRT2 in the leaves of GE-3885 were induced within 30 min of nitrate exposure indicating that there might be a greater nitrogen deficit in leaves and therefore quick transportation of nitrate signals to the leaves. Exposing the plants to increasing nitrate concentrations for 2 h showed that in roots of GE-3885, NR was strongly induced while GS was repressed; however, the pattern was found to be reversed in leaves of GE-1437 indicating that in GE-3885, most of the nitrate might be reduced in the roots but assimilated in leaves and vice-versa. Furthermore, compared with the low-protein genotype, expression of HNRT2 was strongly induced in both roots and shoots of high-protein genotype at the least nitrate concentration supplied. This further indicates that GE-3885 is a quick sensor of nitrogen compared with the low-protein genotype. Furthermore, expression of EcDof1 was also found to overlap the expression of NR, GS, and GOGAT indicating that Dof1 probably regulates the expression of these genes under different conditions by sensing the nitrogen fluctuations around the root zone. 相似文献
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933.
Recent technological advances in Global Positioning System (GPS) telemetry have allowed the production of lightweight devices suitable for use on small mammals. We evaluated the use of GPS bugs on the European hedgehog (Erinaceus europaeus) in a series of static and field tests. Static tests were conducted in five different rural habitats, affording different degrees of obstruction to satellites. GPS bug performance was good in all habitats (fix success rate (FSR): median ≥?66.8 %; location error (LE): mean ≤?13.5 m), except woodland (FSR?=?37.7 %; LE?=?15.6 m), with performance highest in the open pasture habitat (FSR?=?100 %; LE?=?6.4 m). Field tests revealed mean FSR was high (84.6 %), with the use of nesting habitats, the probable cause of most failed fixes. Despite being more expensive, GPS bugs require less survey effort and substantially lower labour costs with unlimited longevity permitting re-use in multiple seasons. We recommend the use of GPS bugs in the spatial ecological study of any small mammal in a rural environment, providing accurate and unbiased movement data. Further performance testing is recommended before deployment on species inhabiting forested habitats where reduced FSR and high LE support the alternative use of very high frequency tracking. 相似文献
934.
Jianmei Luo Meiling Chi Hongyu Wang Huanhuan He Minghua Zhou 《Bioprocess and biosystems engineering》2013,36(12):1889-1896
A convenient and promising alternative to surface modification of carbon mesh anode was fulfilled by electrochemical oxidation in the electrolyte of nitric acid or ammonium nitrate at ambient temperature. It was confirmed that such an anode modification method was low cost and effective not only in improving the efficiency of power generation in microbial fuel cells (MFCs) for synthetic wastewater treatment, but also helping to reduce the period for MFCs start-up. The MFCs with anode modification in electrolyte of nitric acid performed the best, achieving a Coulombic efficiency enhancement of 71 %. As characterized, the electrochemical modification resulted in the decrease of the anode potential and internal resistance but the increase of current response and nitrogen-containing and oxygen-containing functional groups on the carbon surface, which might contribute to the enhancement on the performances of MFCs. 相似文献
935.
Chao Li Adam Schmidt Eran Pichersky Feng Shi A. Daniel Jones 《Metabolomics : Official journal of the Metabolomic Society》2013,9(1):92-101
Discrimination of isomeric methylated metabolites is an important step toward identifying genes responsible for methylation, but presents substantial challenges because authentic standards are often unavailable and mass spectra of isomers have been considered indistinguishable. In this report, an approach is described for identifying methyl group positions in multiply methylated flavonoid metabolites using combinations of tandem mass spectrometry, liquid chromatography retention, and site-selective methylation by recombinant O-methyltransferases from Solanum habrochaites LA1777. The basis for observed fragment ions in tandem mass spectra of multiply methylated myricetin was further established using enzymatic incorporation of deuterium-labeled methyl groups using S-adenosylmethionine-d 3 as precursor. 相似文献
936.
John Draper Amanda J. Lloyd Royston Goodacre Manfred Beckmann 《Metabolomics : Official journal of the Metabolomic Society》2013,9(1):4-29
Producing a comprehensive overview of the chemical content of biologically-derived material is a major challenge. Apart from ensuring adequate metabolome coverage and issues of instrument dynamic range, mass resolution and sensitivity, there are major technical difficulties associated with data pre-processing and signal identification when attempting large scale, high-throughput experimentation. To address these factors direct infusion or flow infusion electrospray mass spectrometry has been finding utility as a high throughput metabolite fingerprinting tool. With little sample pre-treatment, no chromatography and instrument cycle times of less than 5 min it is feasible to analyse more than 1,000 samples per week. Data pre-processing is limited to aligning extracted mass spectra and mass-intensity matrices are generally ready in a working day for a month’s worth of data mining and hypothesis generation. ESI-MS fingerprinting has remained rather qualitative by nature and as such ion suppression does not generally compromise data information content as originally suggested when the methodology was first introduced. This review will describe how the quality of data has improved through use of nano-flow infusion and mass-windowing approaches, particularly when using high resolution instruments. The increasingly wider availability of robust high accurate mass instruments actually promotes ESI-MS from a merely fingerprinting tool to the ranks of metabolite profiling and combined with MS/MS capabilities of hybrid instruments improved structural information is available concurrently. We summarise current applications in a wide range of fields where ESI-MS fingerprinting has proved to be an excellent tool for “first pass” metabolome analysis of complex biological samples. The final part of the review describes a typical workflow with reference to recently published data to emphasise key aspects of overall experimental design. 相似文献
937.
Hirak Der-Torossian Scott A. Asher Jason H. Winnike Ashley Wysong Xiaoying Yin Monte S. Willis Thomas M. O’Connell Marion E. Couch 《Metabolomics : Official journal of the Metabolomic Society》2013,9(3):730-739
Despite recent consensus definitions, lack of specific biomarkers remains a hurdle towards a more accurate and efficient diagnosis of cancer cachexia, distinguishing cachexia as a separate entity from other wasting syndromes. In a previous pilot study, we have shown that cancer-cachectic mice have a unique metabolic fingerprint with distinct glucose and lipid alterations compared to healthy controls. Further metabolomics studies were carried out to investigate differences in metabolic profiles of cancer-cachectic mice to tumor-bearing non-cachectic mice, calorie-restricted mice, and surgically treated cancer-cachectic mice. CD2F1 mice were divided into: (1) Cachexia Group received cachexia-inducing C26 undifferentiated colon carcinoma cells; (2) Tumor-Burden Group received, non-cachectic, P388 lymphoma cells; (3) Caloric-Restriction Group, remaining cancer-free, but subjected to caloric-restriction; (4) Surgery Group, similar to Cachexia Group, but tumors resected mid-experiment; and (5) Control Group aged intact. Baseline, mid-experiment and final serum samples were collected for 1H NMR spectroscopic analysis. After data reduction, unsupervised principal component analysis and orthogonal projections to latent structures analyses demonstrate that the unique metabolic fingerprint is independent of tumor-burden and distinct from profiles of caloric-restriction and aging. Hyperlipidemia, hyperglycemia, and reduced branched-chain amino acids distinguish cachexia from other groups. Furthermore, the profile of surgically treated mice differs from that of cachectic mice, reverting to a profile more congruent with healthy controls indicating cachexia is amenable to correction where surgical cure is possible. That metabolomic analysis of murine serum is able to differentiate cachexia from tumor-burden and caloric-restriction warrants similar translational investigations in patients to explore cancer cachexia’s unique biomarkers. 相似文献
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