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141.
Lolium temulentum L. (Darnel ryegrass) has been proposed to be used as a model species for functional genomics studies in forage and turf grasses,
because it is a self-fertile, diploid species with a short life cycle and is closely related to other grasses. Embryogenic
calluses were induced from mature embryos of a double haploid line developed through anther culture. The calluses were broken
up into small pieces and used for Agrobacterium tumefaciens-mediated transformation. A. tumefaciens strain EHA105 harboring pCAMBIA1301 and pCAMBIA1305.2 vectors were used to infect embryogenic callus pieces. Hygromycin was
used as a selection agent in stable transformation experiments. Hygromycin resistant calluses were obtained after 4–6 weeks
of selection and transgenic plants were produced in 10–13 weeks after Agrobacterium-mediated transformation. Fertile plants were readily obtained after transferring the transgenics to the greenhouse. Transgenic
nature of the regenerated plants was demonstrated by Polymerase chain reaction (PCR), Southern hybridization analysis, and
GUS staining. Progeny analysis showed Mendelian inheritance of the transgenes. The transformation system provides a valuable
tool for functionality tests of candidate genes in forage and turf grasses. 相似文献
142.
Elena Sugrue Nicholas J. Fraser Davis H. Hopkins Paul D. Carr Jeevan L. Khurana John G. Oakeshott Colin Scott Colin J. Jackson 《Applied and environmental microbiology》2015,81(7):2612-2624
The amidohydrolase superfamily has remarkable functional diversity, with considerable structural and functional annotation of known sequences. In microbes, the recent evolution of several members of this family to catalyze the breakdown of environmental xenobiotics is not well understood. An evolutionary transition from binuclear to mononuclear metal ion coordination at the active sites of these enzymes could produce large functional changes such as those observed in nature, but there are few clear examples available to support this hypothesis. To investigate the role of binuclear-mononuclear active-site transitions in the evolution of new function in this superfamily, we have characterized two recently evolved enzymes that catalyze the hydrolysis of the synthetic herbicides molinate (MolA) and phenylurea (PuhB). In this work, the crystal structures, mutagenesis, metal ion analysis, and enzyme kinetics of both MolA and PuhB establish that these enzymes utilize a mononuclear active site. However, bioinformatics and structural comparisons reveal that the closest putative ancestor of these enzymes had a binuclear active site, indicating that a binuclear-mononuclear transition has occurred. These proteins may represent examples of evolution modifying the characteristics of existing catalysts to satisfy new requirements, specifically, metal ion rearrangement leading to large leaps in activity that would not otherwise be possible. 相似文献
143.
144.
Samantha A. Price Samantha S. B. Hopkins 《Biological journal of the Linnean Society. Linnean Society of London》2015,115(1):173-184
Body mass and diet are two fundamental ecological parameters that influence many other aspects of an animal's biology. Thus, the potential physiological and ecological processes linking size and diet have been the subject of extensive research, although the broad macroevolutionary relationship between the two traits remains largely unexplored phylogenetically. Using generalized Ornstein–Uhlenbeck models and data on over 1350 species of mammal, we reveal that evolutionary changes in body mass are consistently associated with dietary changes across mammals. Best‐fitting models find that herbivores are substantially heavier than other dietary groups and that omnivores are frequently intermediate in mass between herbivores and carnivores. Interestingly, although flying and swimming both place very different physical constraints on mass, bats still follow the general mammalian pattern but marine mammals do not. Such differences may be explained by reduced gravitational constraints on size in water along with ecological differences in food availability between aquatic and terrestrial realms, allowing marine carnivores to become the largest mammals on earth. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 115 , 173–184. 相似文献
145.
Heteranassa Smith (Erebidae, Omopterini), native to the southwestern United States and Mexico, includes two recognized species, namely Heteranassa
mima (Harvey) and Heteranassa
fraterna Smith. These are separated mainly by subtle differences in wing color and pattern, leading to speculation about the validity of the described species. This study examines variation in external and internal morphology across the geographic range of the genus, aiming to clarify species limits, describe morphology, and provide a comprehensive assessment of variation within the genus. Results indicate that Heteranassa
fraterna
syn. n., is a junior synonym of Heteranassa
mima. 相似文献
146.
147.
148.
MacKenzie AR Langford B Pugh TA Robinson N Misztal PK Heard DE Lee JD Lewis AC Jones CE Hopkins JR Phillips G Monks PS Karunaharan A Hornsby KE Nicolas-Perea V Coe H Gabey AM Gallagher MW Whalley LK Edwards PM Evans MJ Stone D Ingham T Commane R Furneaux KL McQuaid JB Nemitz E Seng YK Fowler D Pyle JA Hewitt CN 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2011,366(1582):3177-3195
We report measurements of atmospheric composition over a tropical rainforest and over a nearby oil palm plantation in Sabah, Borneo. The primary vegetation in each of the two landscapes emits very different amounts and kinds of volatile organic compounds (VOCs), resulting in distinctive VOC fingerprints in the atmospheric boundary layer for both landscapes. VOCs over the Borneo rainforest are dominated by isoprene and its oxidation products, with a significant additional contribution from monoterpenes. Rather than consuming the main atmospheric oxidant, OH, these high concentrations of VOCs appear to maintain OH, as has been observed previously over Amazonia. The boundary-layer characteristics and mixing ratios of VOCs observed over the Borneo rainforest are different to those measured previously over Amazonia. Compared with the Bornean rainforest, air over the oil palm plantation contains much more isoprene, monoterpenes are relatively less important, and the flower scent, estragole, is prominent. Concentrations of nitrogen oxides are greater above the agro-industrial oil palm landscape than over the rainforest, and this leads to changes in some secondary pollutant mixing ratios (but not, currently, differences in ozone). Secondary organic aerosol over both landscapes shows a significant contribution from isoprene. Primary biological aerosol dominates the super-micrometre aerosol over the rainforest and is likely to be sensitive to land-use change, since the fungal source of the bioaerosol is closely linked to above-ground biodiversity. 相似文献
149.
The effects of plants (corn, soybean, and sunflower) and fertilizer on mobility of more than 60 elements were assessed in a greenhouse experiment. Unplanted columns with the same soil served as controls. Half the columns received fertilizer and all columns were watered at the same rate. At the end of the experiment, the columns were watered to mimic a rainstorm event such that water drained from the bases of the columns, which was collected and analyzed for element content. Soil from between the roots of the plants was also collected and the water-extractable fraction determined. It was expected that (1) more mobile elements, as measured by water extraction, would be leached from the soils at a higher rate compared to less mobile elements, (2) plants would immobilize most elements, but that some would be immobilized, and (3) that this would depend on plant species. The results led to the following conclusions: plants cause metal mobility to vary over a wide range for a specific soil and do mobilize some elements (e.g., Th) while immobilizing others (e.g., U). The effects depended on plant species for some elements. Water-extractable fractions of elements do not predict mobility. 相似文献
150.
Guan R Purohit S Wang H Bode B Reed JC Steed RD Anderson SW Steed L Hopkins D Xia C She JX 《PloS one》2011,6(4):e17822