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排序方式: 共有158条查询结果,搜索用时 31 毫秒
31.
William?N.?SetzerEmail authorView authors OrcID profile 《Journal of molecular modeling》2018,24(3):74
Frankincense oleoresin has been used in traditional medicine for more than 5000 years. The phytochemistry of frankincense (Boswellia spp.) resins includes triterpenoids (including boswellic acids and their derivatives), diterpenoids (cembrenoids and cneorubenoids), and essential oils. The macrocyclic cembrene diterpenoids may play a part in the biological activities of frankincense resin, but neither the biological targets nor the modes of interaction with the targets are currently known. How these macrocycles interact with biological macromolecules likely depends on what conformation(s) are energetically available to them. In this work, a conformational analysis of 15 Boswellia cembrene diterpenoids and 1 verticillane diterpenoid was carried out at the B3LYP/6-31G* and M06-2X/6-31G* levels of theory, including the SM8 aqueous solvation model. The lowest-energy conformations of boscartin B and incensole oxide were the same as the previously reported X-ray crystal structures, while the lowest-energy conformations of boscartins A and C were very similar to the crystal structures. Boscartins D-H and isoincensole oxide showed only one low-energy conformation for each compound and are predicted to be conformationally locked. Incensole, isoincensolol, and serratol are predicted to be conformationally mobile with several low-energy forms. The conformational mobility of Boswellia cembrenoid diterpenoids depends largely on the degree of epoxidation, either oxirane or tetrahydrofuran rings. 相似文献
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Kasi E. Russell‐Lodrigue Stephanie Z. Killeen Thomas A. Ficht Chad J. Roy 《Journal of medical primatology》2018,47(1):75-77
Animals were experimentally infected with Brucella melitensis via aerosol. B. melitensis was cultured from the saliva and vaginal vault of infected animals, corresponding to bacterial dissemination in other target tissues. This is the first report of bacterial dissemination to these mucosal surfaces in a non‐human primate model of brucellosis. 相似文献
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Wataru?MakinoEmail authorView authors OrcID profile Osamu?Miura Felix?Kaiser Mélanie?Geffray Tatsuya?Katsube Jotaro?Urabe 《Biological invasions》2018,20(4):825-842
The Asian brush-clawed shore crab Hemigrapsus takanoi is a non-indigenous species along the Northern European coast. Although the history of range expansion of European H. takanoi has been well-documented, little is known about the genetic compositions of either the introduced European populations or the native Asian ones. We therefore collected H. takanoi broadly from their native Asian sites and introduced European ranges, and genotyped them by sequencing the mitochondrial 16S RNA gene and by analyzing nuclear microsatellite loci. Our results revealed that the H. takanoi Bay of Seine (France) populations consisted of a genetic admixture between populations in Japan and those in the Yellow Sea region. These French populations should be carefully monitored in the future, since the genetic admixture of multiple source populations may accelerate range expansion in non-indigenous organisms. Our results also suggested that shipping lines from East Asia were more probable vectors than historical juvenile oyster transportations from Japan for the foundation of present European H. takanoi populations. Interestingly, gene flow between populations in Japan and those in the Yellow Sea region (i.e., domestic invasion) was not observed despite the higher potential for artificial translocations via shipping lines in the native Asian range compared with those from Asia to Europe. The lack of domestic invasions implied that intra-specific priority effects of the resident H. takanoi populations played an important role in preventing the successful colonization of artificially-transferred individuals. 相似文献
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Timothy R. Baker Oliver L. Phillips Yadvinder Malhi Samuel Almeida Luzmila Arroyo Anthony Di Fiore Terry Erwin Timothy J. Killeen Susan G. Laurance William F. Laurance Simon L. Lewis Jon Lloyd Abel Monteagudo David A. Neill Sandra Patio Nigel C. A. Pitman J. Natalino M. Silva Rodolfo Vsquez Martínez 《Global Change Biology》2004,10(5):545-562
Uncertainty in biomass estimates is one of the greatest limitations to models of carbon flux in tropical forests. Previous comparisons of field‐based estimates of the aboveground biomass (AGB) of trees greater than 10 cm diameter within Amazonia have been limited by the paucity of data for western Amazon forests, and the use of site‐specific methods to estimate biomass from inventory data. In addition, the role of regional variation in stand‐level wood specific gravity has not previously been considered. Using data from 56 mature forest plots across Amazonia, we consider the relative roles of species composition (wood specific gravity) and forest structure (basal area) in determining variation in AGB. Mean stand‐level wood specific gravity, on a per stem basis, is 15.8% higher in forests in central and eastern, compared with northwestern Amazonia. This pattern is due to the higher diversity and abundance of taxa with high specific gravity values in central and eastern Amazonia, and the greater diversity and abundance of taxa with low specific gravity values in western Amazonia. For two estimates of AGB derived using different allometric equations, basal area explains 51.7% and 63.4%, and stand‐level specific gravity 45.4% and 29.7%, of the total variation in AGB. The variation in specific gravity is important because it determines the regional scale, spatial pattern of AGB. When weighting by specific gravity is included, central and eastern Amazon forests have significantly higher AGB than stands in northwest or southwest Amazonia. The regional‐scale pattern of species composition therefore defines a broad gradient of AGB across Amazonia. 相似文献
35.
Enhanced sulfated-proteoglycan core protein synthesis by incubation of rabbit chondrocytes with recombinant transforming growth factor-beta 1 总被引:2,自引:0,他引:2
Rabbit articular chondrocytes were incubated with recombinant transforming-growth-factor-beta 1 (rhTGF-beta 1) and its effect on newly synthesized proteoglycan measured. rhTGF-beta 1 stimulated proteoglycan synthesis at a concentration as low as 5 ng/ml without further increases in radiosulfate incorporation up to 50 ng/ml. The quantitative increase in radiosulfate incorporation in rh-TGF-beta 1-treated chondrocytes was greater in the cell-associated culture compartment than in the medium compartment. rhTGF-beta 1 promoted an increased proteoglycan retention in the cell-associated compartment as evidenced by an increase in the t1/2 of retention from 8 h to 11 h. Specific enhanced synthesis of [35S]-methionine-labeled core proteins was seen in rh-TGF-beta 1-treated chondrocytes. rh-TGF-beta 1 increased the synthesis of the 2 core proteins derived from hydrodynamically large proteoglycans. They possessed apparent molecular weights of greater than 480 kD and 390 kD after 3-5% acrylamide gel electrophoresis. A compartmental analysis revealed that the cell-associated culture compartment contained only the larger of the 2 core proteins derived from large proteoglycans. Two other core proteins with apparent molecular weights 52 kD and 46 kD were also stimulated by rhTGF-beta 1. These results indicated that TGF-beta probably plays a significant role in stimulating proteoglycan core protein synthesis in articular chondrocytes and therefore may be an important growth factor in the restoration of cartilage extracellular matrix after injury. 相似文献
36.
Y. Malhi O.L. Phillips J. Lloyd T. Baker J. Wright S. Almeida L. Arroyo T. Frederiksen J. Grace N. Higuchi T. Killeen W.F. Laurance C. Leao S. Lewis P. Meir A. Monteagudo D. Neill P. Núez Vargas S.N. Panfil S. Patio N. Pitman C.A. Quesada A. Rudas‐Ll. R. Salomo S. Saleska N. Silva M. Silveira W.G. Sombroek R. Valencia R. Vsquez Martínez I.C.G. Vieira B. Vinceti 《植被学杂志》2002,13(3):439-450
Abstract. The Amazon basin is likely to be increasingly affected by environmental changes: higher temperatures, changes in precipitation, CO2 fertilization and habitat fragmentation. To examine the important ecological and biogeochemical consequences of these changes, we are developing an international network, RAINFOR, which aims to monitor forest biomass and dynamics across Amazonia in a co‐ordinated fashion in order to understand their relationship to soil and climate. The network will focus on sample plots established by independent researchers, some providing data extending back several decades. We will also conduct rapid transect studies of poorly monitored regions. Field expeditions analysed local soil and plant properties in the first phase (2001–2002). Initial results suggest that the network has the potential to reveal much information on the continental‐scale relations between forest and environment. The network will also serve as a forum for discussion between researchers, with the aim of standardising sampling techniques and methodologies that will enable Amazonian forests to be monitored in a coherent manner in the coming decades. 相似文献
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W Richard Mukabana Khadija Kannady G Michael Kiama Jasper N Ijumba Evan M Mathenge Ibrahim Kiche Gamba Nkwengulila Leonard Mboera Deo Mtasiwa Yoichi Yamagata Ingeborg van Schayk Bart GJ Knols Steven W Lindsay Marcia Caldas de Castro Hassan Mshinda Marcel Tanner Ulrike Fillinger Gerry F Killeen 《Malaria journal》2006,5(1):1-14