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981.
982.
The proof of efficacy of phytopreparations and the determination of their mode of action are permanent challenges for an evidence-based phytotherapy. The technology platform of genomics, proteomics and metabolomics ("-omic-" technologies) are high-throughput technologies. They increase substantially the number of proteins/genes that can be detected simultaneously and have the potential to relate complex mixtures to complex effects in the form of gene/protein expression profiles. Provided that phytopreparation-specific signatures in the form of gene/protein expression profiles can be developed, these technologies will be useful for the chemical and pharmacological standardization and the proof of the toxicological potential of a plant extract. Over a long-term perspective they may economize the proof of efficacy, the determination of the mode of action of phytomedicines and allow to investigate herbal extracts without prominent active principle(s). The application of this genomics revealed already that gene expression profiles induced by single drugs and the ones induced by the combination of the same drugs can be entirely different. These results make the information of the mode of action of isolated "active principles/lead substances" of phytopreparations questionable. The application of the "-omic-" technologies may lead to a change of paradigms towards the application of complex mixtures in medicine and open the new field of phytogenomics, -proteomics and -metabolomics.  相似文献   
983.
SAXIFRAGA BRYOIDES L. is one of the plant species reaching the upper limits of distribution for flowering plants in the European Alps. Because of its abundance in the subnival and nival zones, we expected S. BRYOIDES to reproduce efficiently in the highly stochastic climate at higher altitudes. Investigations were carried out at two subnival sites (2650 m and 2880 m a.s.l.) in the Austrian Alps. We studied flowering phenology, dynamics of seed development, and reproductive success in the climatically different years from 2001 - 2004. For a nival plant species, S. BRYOIDES showed a particularly long prefloration period (6 - 9 weeks). From onset of anthesis until seed maturity took an individual flower another 6 - 7 weeks and all individuals at a site 9 - 10 weeks. The length of the prefloration period and seed histogenesis was temperature-dependent, whereas seed maturation seemed to be endogenously controlled. Only in the exceptionally long and warm growing season of 2003 did all fruits mature at a site. In the other years, the onset of winter conditions halted development in many fruits before maturity. The seed/ovule ratio of mature fruits was around 0.7 in all years. The relative reproductive success (RRS) ranged from zero to 0.7, depending on the site and year. In conclusion, S. BRYOIDES needs an unexpectedly long time to undergo reproductive development. Though fruit maturation is uncertain, the high S/O ratio of single intact fruits results in at least a small seed crop in most years. This seems to be sufficient to assure the spread and maintenance of S. BRYOIDES at higher altitudes. As a seed-risk strategist (Molau,1993), S. BRYOIDES would clearly benefit from a prolonged growing season, which might occur more often if climate warming continues.  相似文献   
984.
Molecular and Cellular Biochemistry - The nicotinamide adenine dinucleotide (NAD+) is an essential redox cofactor, involved in various physiological and molecular processes, including energy...  相似文献   
985.
Mycopathologia - Paracoccidioidomycosis (PCM) is a systemic mycosis caused by a group of cryptic species embedded in the Paracoccidioides brasiliensis complex and Paracoccidioides lutzii. Four...  相似文献   
986.
Flooding is detrimental for plants, primarily because of restricted gas exchange underwater, which leads to an energy and carbohydrate deficit. Impeded gas exchange also causes rapid accumulation of the volatile ethylene in all flooded plant cells. Although several internal changes in the plant can signal the flooded status, it is the pervasive and rapid accumulation of ethylene that makes it an early and reliable flooding signal. Not surprisingly, it is a major regulator of several flood-adaptive plant traits. Here, we discuss these major ethylene-mediated traits, their functional relevance, and the recent progress in identifying the molecular and signaling events underlying these traits downstream of ethylene. We also speculate on the role of ethylene in postsubmergence recovery and identify several questions for future investigations.Come gather round people wherever you roamAnd admit that the waters around you have grownAnd accept it that soon you’ll be drenched to the boneIf your time to you is worth savingAnd you’d better start swimming or you’ll sink like a stoneFor the times they are a-changing…THE TIMES THEY ARE A-CHANGIN''Words and Music by Bob DylanCopyright © 1963, 1964 Warner Bros. Inc.Copyright Renewed 1991, 1992 Special Rider MusicInternational Copyright Secured. All Rights Reserved.Reprinted by Permission.Fifty years later, these prophetic words from Dylan’s legendary song strangely ring true. We live in an increasingly wetter world. Flooding events have become more frequent, severe, and unpredictable, a trend that is linked to climate change (Arnell and Liu, 2001; Hirabayashi et al., 2013). Not only do they destroy human lives, but also, they affect plants, on which we depend so much. Flooding negatively affects plant biodiversity, natural species distribution, and global food production because of crop losses (Silvertown et al., 1999; Normile, 2008), because most terrestrial plants, including major crops, are extremely sensitive to wet conditions. It might seem counterintuitive that a molecule so biologically benign and indispensable for plant growth and function is harmful when present in excess. However, this is attributed to the fact that water is an extremely poor medium for gas diffusion. Hampered gas exchange with flooded organs leads to restriction of two vital plant processes: photosynthesis and respiration. The problem is compounded by stagnant and/or turbid floodwaters, because this further restricts the availability of light and oxygen. An energy crisis quickly results owing to an imbalance between energy production and consumption, ultimately causing plant mortality. Flooding survival tactics in the plant kingdom vary widely and include several morphological, anatomical, physiological, and molecular changes that can prolong survival and even facilitate permanent habitation in wet environments (Voesenek and Bailey-Serres, 2015). Initiation of these changes requires accurate and timely perception of water inundation to initiate adaptive responses. The term flooding encompasses both waterlogging and submergence. Waterlogging implies soil flooding, where only roots are exposed to wet conditions. Submergence also immerses the shoot (partially or wholly). Unless otherwise specified, this nomenclature will be used throughout this article.  相似文献   
987.
988.
Provided that a selective accumulation of 10B-containing compounds is introduced in tumor cells, following irradiation by thermal neutrons produces high-LET alpha-particles (4He) and recoiling lithium-7 (7Li) nuclei emitted during the capture of thermalized neutrons (0.025 eV) from 10B. To estimate the biological effectiveness of this boron neutron capture [10B(n,α)7Li] reaction, the chromosome aberration assay and the flow cytometry apoptosis assay were applied. At the presence of the clinically used compounds BSH (sodium borocaptate) and BPA (p-boronophenylalanine), human lymphocytes were irradiated by sub-thermal neutrons. For analyzing chromosome aberrations, human lymphocytes were exposed to thermally equivalent neutron fluences of 1.82 × 1011 cm?2 or 7.30 × 1011 cm?2 (corresponding to thermal neutron doses of 0.062 and 0.248 Gy, respectively) in the presence of 0, 10, 20, and 30 ppm of BSH or BPA. Since the kerma coefficient of blood increased by 0.864 × 10?12 Gy cm2 per 10 ppm of 10B, the kerma coefficients in blood increase from 0.34 × 10?12 cm2 (blood without BSH or BPA) up to 2.93 × 10?12 Gy cm2 in the presence of 30 ppm of 10B. For the 10B(n, α)7Li reaction, linear dose–response relations for dicentrics with coefficients α = 0.0546 ± 0.0081 Gy?1 for BSH and α = 0.0654 ± 0.0075 Gy?1 for BPA were obtained at 0.062 Gy as well as α = 0.0985 ± 0.0284 Gy?1 for BSH and α = 0.1293 ± 0.0419 Gy?1 for BPA at 0.248 Gy. At both doses, the corresponding 10B(n, α)7Li reactions from BSH and BPA are not significantly different. A linear dose–response relation for dicentrics also was obtained for the induction of apoptosis by the 10B(n, α)7Li reaction at 0.248 Gy. The linear coefficients α = 0.0249 ± 0.0119 Gy?1 for BSH and α = 0.0334 ± 0.0064 Gy?1 for BPA are not significantly different. Independently of the applied thermal neutron doses of 0.062 Gy or 0.248 Gy, the 10B(n, α)7Li reaction from 30 ppm BSH or BPA induced an apparent RBE of about 2.2 for the production of dicentrics as compared to exposure to thermal neutrons alone. Since the apparent RBE value is defined as the product of the RBE of a thermal neutron dose alone times a boron localization factor which depends on the concentration of a 10B-containing compound, this localization factor determines the biological effectiveness of the 10B(n, α)7Li reaction.  相似文献   
989.
990.
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