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151.
Alnajjar A Chabane Sari D Abuharfeil N Hudaib M Aburjai T 《Prostaglandins, leukotrienes, and essential fatty acids》2006,74(6):347-356
Dietary lipid manipulation may affect a great number of immune parameters, such as lymphocyte proliferation, cytokine synthesis. In this study, lymphocytes of diabetic type 2 were incubated with different polyunsaturated fatty acid (docosahexaenoic, eicosapentaenoic, arachidonic acid) for investigated their effect on lymphoproliferation response, the concentration of interleukin 2 produced in each essay and phospholipid fatty acid composition of lymphocyte membrane. Our results found that the concanavalin A and insulin increase significantly the proliferative response while eicosapentaenoic, arachidonic and docosahexaenoic acid inhibited that by different degrees: 47%, 37% and 19%, respectively, for healthy subjects and 39%, 29% and 13% for diabetes. However, the concentration of IL-2 produced in presence of either docosahexaenoic, eicosapentaenoic or arachidonic acid was significantly reduced by 36%, 32% and 39%, respectively, in controls while 16%, 15% and 23%, respectively, in diabetics. On the other hand, the tested fatty acids demonstrated a major impact on the fatty acid composition of different phospholipid fractions of lymphocyte membrane but these fractions were different in their response to each fatty acid examined. For instance, the addition of docosahexaenoic acid to culture media was accompanied with a predominant composition of docosahexaenoic acid in phospholipid fractions. Also, our results showed a notable increased proportion of arachidonic, eicosapentaenoic and docosahexaenoic acids in control phospholipid fractions than those of diabetic. 相似文献
152.
Graham N. Scofield Sari A. Ruuska Naohiro Aoki David C. Lewis Linda M. Tabe Colin L. D. Jenkins 《Annals of botany》2009,103(6):859-868
Background and Aims
Carbohydrate temporarily accumulates in wheat stems during the early reproductive growth phase, predominantly as water soluble carbohydrate (WSC), and is subsequently remobilized during grain filling. Starch has also been reported as a minor storage carbohydrate component in wheat stems, but the details are lacking.Methods
The accumulation and localization of starch in wheat stem and leaf sheath tissue over a developmental period from 6 d before anthesis to 35 d after anthesis was investigated.Key Results
The region of the peduncle enclosed by the flag-leaf sheath, and the penultimate internode were the main tissues identified as containing starch, in which the starch grains localized to the storage parenchyma cells. In contrast, the exposed peduncle lacked starch grains. Starch grains were also found in the flag-leaf and second-leaf sheath. Plants grown in low-nitrogen conditions exhibited increased storage of both starch and WSC compared with plants grown in high-nitrogen supply.Conclusions
The major accumulation and decrease of starch occurred temporally independently to that for WSC, suggesting a different functional role for starch in wheat stems. Starch reutilization concomitant with peduncle growth, and the early development of the reproductive structures, suggested a role in provision of energy and/or carbon scaffolds for these growth processes.Key words: Carbohydrate partitioning, peduncle, starch, wheat stem, storage parenchyma, Triticum aestivum 相似文献153.
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
154.
155.
Glycomics of bone marrow-derived mesenchymal stem cells can be used to evaluate their cellular differentiation stage 总被引:1,自引:0,他引:1
Annamari Heiskanen Tia Hirvonen Hanna Salo Ulla Impola Anne Olonen Anita Laitinen Sari Tiitinen Suvi Natunen Olli Aitio Halina Miller-Podraza Manfred Wuhrer André M. Deelder Jari Natunen Jarmo Laine Petri Lehenkari Juhani Saarinen Tero Satomaa Leena Valmu 《Glycoconjugate journal》2009,26(3):367-384
Human mesenchymal stem cells (MSCs) are adult multipotent progenitor cells. They hold an enormous therapeutic potential, but
at the moment there is little information on the properties of MSCs, including their surface structures. In the present study,
we analyzed the mesenchymal stem cell glycome by using mass spectrometric profiling as well as a panel of glycan binding proteins.
Structural verifications were obtained by nuclear magnetic resonance spectroscopy, mass spectrometric fragmentation, and glycosidase
digestions. The MSC glycome was compared to the glycome of corresponding osteogenically differentiated cells. More than one
hundred glycan signals were detected in mesenchymal stem cells and osteoblasts differentiated from them. The glycan profiles
of MSCs and osteoblasts were consistently different in biological replicates, indicating that stem cells and osteoblasts have
characteristic glycosylation features. Glycosylation features associated with MSCs rather than differentiated cells included
high-mannose type N-glycans, linear poly-N-acetyllactosamine chains and α2-3-sialylation. Mesenchymal stem cells expressed SSEA-4 and sialyl Lewis x epitopes. Characteristic
glycosylation features that appeared in differentiated osteoblasts included abundant sulfate ester modifications. The results
show that glycosylation analysis can be used to evaluate MSC differentiation state. 相似文献
156.
Pihlasalo S Hara M Hänninen P Slotte JP Peltonen J Härmä H 《Analytical biochemistry》2009,384(2):231-5144
There is an increasing need for developing simple assay formats for biomedical screening purposes. Assays on cell membranes have become important in studies of receptor-ligand interactions and signal pathways. Here luminescence energy transfer was studied on liposomes containing europium ion chelated to 4,4,4-trifluoro-1-(2-naphthalenyl)-1,3-butanedione and trioctylphosphine oxide. Energy transfer efficiency was characterized with biotin-streptavidin interaction, and a model assay concept for a homogeneous time-resolved luminescence resonance energy transfer (LRET) assay was developed. Acceptor-labeled streptavidin was bound to biotinylated lipids on the liposomes, leading to close proximity of the LRET pair. The liposome-based LRET assay was optimized for dye incorporation and concentration, biotinylation degree, liposome size, and kinetics. Sensitivity for a competitive biotin assay was at a picomolar range with a coefficient of variation from 7 to 20%. The developed lipid membrane-based system was feasible in separation free LRET assay concept with high sensitivity, indicating that the assay principle can potentially be used for biologically more relevant target molecules. 相似文献
157.
158.
Adnane Boualem Christelle Troadec Irina Kovalski Marie-Agnes Sari Rafael Perl-Treves Abdelhafid Bendahmane 《PloS one》2009,4(7)
Andromonoecy is a widespread sexual system in angiosperms, characterized by plants carrying both male and bisexual flowers. Monoecy is characterized by the presence of both male and female flowers on the same plant. In cucumber, these sexual forms are controlled by the identity of the alleles at the M locus. In melon, we recently showed that the transition from monoecy to andromonoecy result from a mutation in 1-aminocyclopropane-1-carboxylic acid synthase (ACS) gene, CmACS-7. To isolate the andromonoecy gene in cucumber we used a candidate gene approach in combination with genetical and biochemical analysis. We demonstrated co-segregation of CsACS2, a close homolog of CmACS-7, with the M locus. Sequence analysis of CsACS2 in cucumber accessions identified four CsACS2 isoforms, three in andromonoecious and one in monoecious lines. To determine whether the andromonoecious phenotype is due to a loss of ACS enzymatic activity, we expressed the four isoforms in Escherichia coli and assayed their activity in vitro. Like in melon, the isoforms from the andromonoecious lines showed reduced to no enzymatic activity and the isoform from the monoecious line was active. Consistent with this, the mutations leading andromonoecy were clustered in the active site of the enzyme. Based on this, we concluded that active CsACS2 enzyme leads to the development of female flowers in monoecious lines, whereas a reduction of enzymatic activity yields hermaphrodite flowers. Consistent with this, CsACS2, like CmACS-7 in melon, is expressed specifically in carpel primordia of buds determined to develop carpels. Following ACS expression, inter-organ communication is likely responsible for the inhibition of stamina development. In both melon and cucumber, flower unisexuality seems to be the ancestral situation, as the majority of Cucumis species are monoecious. Thus, the ancestor gene of CmACS-7/CsACS2 likely have controlled the stamen development before speciation of Cucumis sativus (cucumber) and Cucumis melo (melon) that have diverged over 40 My ago. The isolation of the genes for andromonoecy in Cucumis species provides a molecular basis for understanding how sexual systems arise and are maintained within and between species. 相似文献
159.
Archaea in dry soil environments 总被引:1,自引:0,他引:1
Archaea belong to the least well known major group of soil inhabiting microbes as the concept of the very existence of the
archaea was introduced only in 1977 and the domain of Archaea established in 1990. The first reports of finding these organisms
in soils were published even later. This paper will review the research carried out of the archaea in dry moderate soil environments.
It will particularly consider the specific habitats where the archaea live in soils, as well as their associations with other
organisms. There is thus far relatively little knowledge about the metabolism of the soil archaea, but the knowledge about
their exact habitats and associations as well as their genetic potential point the way to discovering more about the different
soil archaeal functions. 相似文献
160.
Responses of Vegetation and Ecosystem CO2 Exchange to 9 Years of Nutrient Addition at Mer Bleue Bog 总被引:1,自引:0,他引:1
Anthropogenic nitrogen (N) loading has the potential to affect plant community structure and function, and the carbon dioxide
(CO2) sink of peatlands. Our aim is to study how vegetation changes, induced by nutrient input, affect the CO2 exchange of a nutrient-limited bog. We conducted 9- and 4-year fertilization experiments at Mer Bleue bog, where we applied
N addition levels of 1.6, 3.2, and 6.4 g N m−2 a−1, upon a background deposition of about 0.8 g N m−2 a−1, with or without phosphorus and potassium (PK). Only the treatments 3.2 and 6.4 g N m−2 a−1 with PK significantly affected CO2 fluxes. These treatments shifted the Sphagnum moss and dwarf shrub community to taller dwarf shrub thickets without moss, and the CO2 responses depended on the phase of vegetation transition. Overall, compared to the large observed changes in the vegetation,
the changes in CO2 fluxes were small. Following Sphagnum loss after 5 years, maximum ecosystem photosynthesis (Pgmax) and net CO2 exchange (NEEmax) were lowered (−19 and −46%, respectively) in the highest NPK treatment. In the following years, while shrub height increased,
the vascular foliar biomass did not fully compensate for the loss of moss biomass; yet, by year 8 there were no significant
differences in Pgmax and NEEmax between the nutrient and the control treatments. At the same time, an increase (24–32%) in ecosystem respiration (ER) became
evident. Trends in the N-only experiment resembled those in the older NPK experiment by the fourth year. The increasing ER
with increasing vascular plant and decreasing Sphagnum moss biomass across the experimental plots suggest that high N deposition may lessen the CO2 sink of a bog. 相似文献