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81.
Edoardo Daly Sari Palmroth Paul Stoy Mario Siqueira A. Christopher Oishi Jehn-Yih Juang Ram Oren Amilcare Porporato Gabriel G. Katul 《Biogeochemistry》2009,94(3):271-287
Profiles of subsurface soil CO2 concentration, soil temperature, and soil moisture, and throughfall were measured continuously during the years 2005 and
2006 in 16 locations at the free air CO2 enrichment facility situated within a temperate loblolly pine (Pinus taeda L.) stand. Sampling at these locations followed a 4 by 4 replicated experimental design comprised of two atmospheric CO2 concentration levels (ambient [CO2]a, ambient + 200 ppmv, [CO2]e) and two soil nitrogen (N) deposition levels (ambient, ambient + fertilization at 11.2 gN m−2 year−1). The combination of these measurements permitted indirect estimation of belowground CO2 production and flux profiles in the mineral soil. Adjacent to the soil CO2 profiles, direct (chamber-based) measurements of CO2 fluxes from the soil–litter complex were simultaneously conducted using the automated carbon efflux system. Based on the
measured soil CO2 profiles, neither [CO2]e nor N fertilization had a statistically significant effect on seasonal soil CO2, CO2 production, and effluxes from the mineral soil over the study period. Soil moisture and temperature had different effects
on CO2 concentration depending on the depth. Variations in CO2 were mostly explained by soil temperature at deeper soil layers, while water content was an important driver at the surface
(within the first 10 cm), where CO2 pulses were induced by rainfall events. The soil effluxes were equal to the CO2 production for most of the time, suggesting that the site reached near steady-state conditions. The fluxes estimated from
the CO2 profiles were highly correlated to the direct measurements when the soil was neither very dry nor very wet. This suggests
that a better parameterization of the soil CO2 diffusivity is required for these soil moisture extremes. 相似文献
82.
83.
Elena Cassani Edoardo Bertolini Francesco Cerino Badone Michela Landoni Dario Gavina Alberto Sirizzotti Roberto Pilu 《Molecular breeding : new strategies in plant improvement》2009,24(4):375-385
The “green revolution” involving mainly wheat and rice was based on the use by breeders of semidominant mutations involved
in the signal transduction pathway of Gibberellin (GA). In particular, mutations in the Reduced height (Rht) gene of wheat have been used to reduce plant height and consequently to avoid storm damage and lodging. These genes have
been cloned and they encode for DELLA proteins which contain an N-terminal DELLA and a VHYNP domain essential for GA-dependent
degradation of these proteins. In maize several mutations have been isolated which affect gibberellin biosynthesis and perception
and in particular, mutations in Dwarf8 (D8) gene cause a severe dwarfing phenotype. D8 gene has been identified as an orthologue of Rht (Reduced height), Slr1(Slender rice 1) and Gibberellic Acid Insensitive (GAI) genes, this latter is a negative regulator of GA response in Arabidopsis. In this work, for the first time, we isolated and characterized a single amino acid insertion in the VHYNP domain of D8 maize gene causing the appearance of a dominant dwarf mutation. This spontaneous mutation, named D8-1023, showed a phenotype which is less severe in comparison with the other D8 mutants previously isolated which have modifications
in the DELLA domain. This mutant appears to be an useful tool either to study the mechanism of GA-modulated growth in plants
or to lower the height of maize tropical germplasm for breeding purposes. 相似文献
84.
The Novel PMCA2 Pump Mutation Tommy Impairs Cytosolic Calcium Clearance in Hair Cells and Links to Deafness in Mice 总被引:1,自引:0,他引:1
Mario Bortolozzi Marisa Brini Nick Parkinson Giulia Crispino Pietro Scimemi Romolo Daniele De Siati Francesca Di Leva Andrew Parker Saida Ortolano Edoardo Arslan Steve D. Brown Ernesto Carafoli Fabio Mammano 《The Journal of biological chemistry》2010,285(48):37693-37703
The mechanotransduction process in hair cells in the inner ear is associated with the influx of calcium from the endolymph. Calcium is exported back to the endolymph via the splice variant w/a of the PMCA2 of the stereocilia membrane. To further investigate the role of the pump, we have identified and characterized a novel ENU-induced mouse mutation, Tommy, in the PMCA2 gene. The mutation causes a non-conservative E629K change in the second intracellular loop of the pump that harbors the active site. Tommy mice show profound hearing impairment from P18, with significant differences in hearing thresholds between wild type and heterozygotes. Expression of mutant PMCA2 in CHO cells shows calcium extrusion impairment; specifically, the long term, non-stimulated calcium extrusion activity of the pump is inhibited. Calcium extrusion was investigated directly in neonatal organotypic cultures of the utricle sensory epithelium in Tommy mice. Confocal imaging combined with flash photolysis of caged calcium showed impairment of calcium export in both Tommy heterozygotes and homozygotes. Immunofluorescence studies of the organ of Corti in homozygous Tommy mice showed a progressive base to apex degeneration of hair cells after P40. Our results on the Tommy mutation along with previously observed interactions between cadherin-23 and PMCA2 mutations in mouse and humans underline the importance of maintaining the appropriate calcium concentrations in the endolymph to control the rigidity of cadherin and ensure the function of interstereocilia links, including tip links, of the stereocilia bundle. 相似文献
85.
86.
Muscle larvae of Trichinella isolates from two outbreaks in Korea were analyzed by a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and multiple-PCR. All of the muscle larvae showed a band similar to that of T. spiralis larvae of the reference strain. The two Korean Trichinella isolates (isolate code ISS623 and ISS1078) might be classifiable to Trichinella spiralis. 相似文献
87.
Summary This paper is focused on the facies associations of an Early-Middle Norian stratigraphic succession cropping outin the Northern
Calabria (Buonvicino, Cosenza). These carbonate deposits, pertaining to the Verbicaro Unit, represent a dolomitized platform
characterized by a clear dominance of automicrites over skeletal metazoans.
On the basis of the chronostatigraphic data and sedimentary evolution, two stratigraphic units have been distinguished: the
Lower Unit (object of the present paper) and the Upper Unit. The Lower Unit consists of an Early-Middle Norian high-relief
prograding carbonate platform. The Upper Unit is represented by Middle p.p.-Upper Norian basinal deposits.
Three main facies associations, indicative of different depositional settings, have been identified.
The inner platform facies association is characterized by automicrite (cauliflower-columnar subordinate planar stromatolites)
associated with detrital carbonates (intraclastic breccia, bioclastic grainstone and packstone). Apeculiar facies is represented
by megalodontid-bearing beds. Mud-cracked horizons and low-developed teepees occur quite frequently.
The margin facies association is dominated by automicrite (planar to low relief stromatolites associated with thrombolitic
fenestral boundstone) and detrital carbonates with subaerial exposure features.
The slope facies association includes detrital carbonates (breccia/megabreccia) associated with serpulid/sphinctozoan bioconstructions
and automicrite (planar stromatolites/thrombolitic boundstone).
The whole carbonate body is completely dolomitized; nevertheless the morphology and microarchitecture of carbonate components
(cements, grains and automicrite) is still clearly recognizable. The dolomite Mg content ranges from 40 to 48 mole%, sometimes
reaching the stoichiometric value.
Cements, primary and late, represent a minor component of the rock volume; they occur more frequently on the margin and upper
slope setting. Quantitative tacies analyses lead to the following conclusions:
The sedimentary facies and the low-diversity fossil associations seem to indicate a stressed marine environment; the platform
margin probably flanked an intra-platform basin, not an open marine basin. 相似文献
– | ⊙ the entire platform is largely led by automicrite (50% in the inner platform, 70% in the margin, and 30% in the slope), with planar to columnar stromatolitic or thrombolitic fabrics; |
– | ⊙ primary skeletal framework is usually missing, although small bioconstructions of sphinctozoans and, subordinately, serpulids, occur on the slope; |
– | ⊙ automicrite has been affected by early cementation, as witnessed by non-gravitative microfabric, early fracturing and boring. |
88.
89.
Pier L. Biagi Alessandra Bordoni Silvana Hrelia Michele Celadon Edoardo Turchetto 《The Journal of nutritional biochemistry》1993,4(12):690-694
Polyenylphosphatidylcholine is a choline-glycerophospholipid containing up to 80% of total fatty acids as linoleic acid and may be an important factor in ensuring normal functioning of cell membranes. We tested the effect of a polyenylphosphatidylcholine-supplemented diet and compared it with both a trilinolein-supplemented and a laboratory chow diet on the fatty acid composition, microviscosity, and delta-6-desaturase activity of liver microsomal membranes of 12-month-old rats, in the absence or presence of oxidative stress induced by adriamycin. Polyenylphosphatidylcholine- and trilinolein-supplemented diets showed a similar increase in linoleic acid content and delta-6-desaturase activity in liver microsomes, indicating that low amounts of linoleic acid are able to partially restore the enzyme activity in old rats, independent of the source of linoleic acid. After adriamycin treatment, delta-6-desaturase activity increased in polyenylphosphatidylcholine and trilinolein groups, indicating a protective mechanism against the damage induced by polyunsaturated fatty acid peroxidation. The measurement of malondialdehyde production showed a protective effect on adriamycin-induced lipid peroxidation by polyenylphosphatidylcholine supplementation only. Microsomal membrane microviscosity did not change independent of diet and adriamycin treatment, suggesting that the response of microsomes to lipid peroxidation might be the maintenance of a given membrane order. Administration of polyenylphosphatidylcholine can prevent or minimize the liver damage induced by adriamycin treatment. 相似文献
90.
Emilia Bramanti Edoardo Benedetti Claudio Nicolini Tatiana Berzina Victor Erokhin Aldo D'Alessio Enzo Benedetti 《Biopolymers》1997,42(2):227-237
A qualitative and quantitative analysis of the conformation of Langmuir-Blodgett (LB) dried films of cytochrome C on silicon wafers was performed by Fourier transform ir (FTIR) spectroscopy. A deconvolution procedure was applied to the amide I band analysis, in order to determine the percentage of the different secondary structures. Qualitative analysis was performed by examining difference spectra. Films obtained by spreading protein solutions at pH 7.4 and 1, dried at 25 and 100°C, on silicon wafers were also examined in order to detect spectral components associated with denatured protein domains, and to compare them with cytochrome C LB films. FTIR spectroscopy showed that the following important changes characterise LB film spectra: (a) the α-helix component is higher (its percentage is 57 and 54%) than the one estimated in dried film obtained by spreading the solutions at pH 7.4 on a silicon substrate (43%), (b) there is an increase in the intensity of bands attributed to protonated carboxy group bands, involved and not involved in the formation of hydrogen bonds, and a decrease in those attributed to deprotonated carboxy groups, (c) the intensity of several bands attributed to aromatic amino acids and aliphatic chains increases, and (d) bands due to O(SINGLEBOND)H stretching vibrations of crystallization water are present. These conformational changes could be induced by protein-protein interaction caused by the close packing of molecules that occurs during LB film formation; it cannot be excluded that they may be accompanied by partial changes in the tertiary structure of the protein. A preferential orientation of protein molecules in LB films is also a possibility. © 1997 John Wiley & Sons, Inc. Biopoly 42: 227–237, 1997 相似文献