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131.
Itzhak A. Rosner Andrea Manni Charles J. Malemud Beata Boja Roland W. Moskowitz 《Biochemical and biophysical research communications》1982,106(4):1378-1382
Recent experimental studies suggest a role for estrogens in chondrocyte metabolism and the development and treatment of osteoarthritis. Type I cytoplasmic estradiol receptors were found in articular chondrocytes. The presence of these receptors supports a possible mechanism for previous observations on estrogen suppressive effects on cartilage proteoglycan synthesis and offers a basis for further study on the role of estrogens in the physiology of cartilage and in the pathogenesis and treatment of osteoarthritis. 相似文献
132.
Background and aims
Legume species in the fynbos vegetation of the Cape Floristic Region, that fix N2 in soils with low P, may have evolved for enhanced acquisition and efficient use of P. It was hypothesized that N2-fixing and combined-N supplied (N-supplied) A. linearis, P. calyptrata and C. genistoides are adapted to low P and would be relatively unresponsive to increased P of 100 μM.Methods
18 legume species were evaluated for their nodulation response to low P availability. The N X P interaction was then examined in A. linearis, P. calyptrata and C. genistoides reliant on either N2-fixation or 300 μM N (NH4NO3), and receiving 0.1, 1.0, 10 and 100 μM P (NaH2PO4).Results
In the species selection experiment, A. linearis, P. calyptrata and C. genistoides, with the greatest nodule fresh weight (FW) and nodule FW to root FW ratio, were the most prolific nodulating species. In the N X P experiment, with low P supply, the biomass of N2-fixing P. calyptrata and C. genistoides was consistently greater than that of N-supplied plants. In contrast, with high P supply of 100 μM P, all N-supplied plants accumulated more biomass than the corresponding N2-fixing plants. High P-use efficiency, poor down-regulation of P uptake and P storage was evident in A. linearis and P. calyptrata.Conclusion
The growth response to P and the significant N X P interactions indicate that N2-fixing and N-supplied plants were not adapted to low P, but rather colimited by both N and P. 相似文献133.
134.
The population dynamics of Pristiphora abietina , an important pest in Norway spruce in central Europe, is significantly influenced by factors causing nymph mortality during the cocoon stage. In contrast to other findings reported in the literature, pathogenic fungi of the genera Beauveria, Paecilomyces and Metarhizium were found to be important natural enemies. Their epizootics occur soon after cocoon formation by the larvae in the ground litter, i.e. in June/July, and progress only slightly in autumn and winter. 'Obscure' mortality, which is ascribed mainly to abiotic factors, is observed more in winter. Field and laboratory experiments as well as histological analyses suggest that the fungal disease in nymphs is due to spore contamination occurring before cocoon formation, and that penetration of fungi from outside through the intact cocoon wall appears very unlikely. Thus, the infection rate of cocoons depends on the spore density in the ground litter of spruce stands during the cocoon spinning period of May/June. Perspectives for biocontrol arising from these findings are discussed. 相似文献
135.
Summary. Tuberous sclerosis (TSC) is an autosomal dominantly inherited disease affecting 1 in 6000 individuals. The TSC gene products,
hamartin and tuberin, form a complex, of which tuberin is assumed to be the functional component being involved in a wide
variety of different cellular processes. Tuberin has been demonstrated to be localized to both, the cytoplasm and the nucleus.
The cytoplasmic/nuclear localization of tuberin is known to be regulated by the serine/threonine protein kinase Akt. Akt also
regulates the cytoplasmic/nuclear localization of the cyclin-dependent kinase inhibitor p27. In this study the localization
of these two Akt-regulated proteins was analysed in different cell lines. 相似文献
136.
We discuss inference for data with repeated measurements at multiple levels. The motivating example is data with blood counts from cancer patients undergoing multiple cycles of chemotherapy, with days nested within cycles. Some inference questions relate to repeated measurements over days within cycle, while other questions are concerned with the dependence across cycles. When the desired inference relates to both levels of repetition, it becomes important to reflect the data structure in the model. We develop a semiparametric Bayesian modeling approach, restricting attention to two levels of repeated measurements. For the top-level longitudinal sampling model we use random effects to introduce the desired dependence across repeated measurements. We use a nonparametric prior for the random effects distribution. Inference about dependence across second-level repetition is implemented by the clustering implied in the nonparametric random effects model. Practical use of the model requires that the posterior distribution on the latent random effects be reasonably precise. 相似文献
137.
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139.
Sabine Rosner Berthold Heinze Tadeja Savi Guillermina Dalla‐Salda 《Physiologia plantarum》2019,165(4):843-854
More frequently occurring, drought waves call for a deeper understanding of tree hydraulics and fast and easily applicable methods to measure drought stress. The aim of this study was to establish empirical relationships between the percent loss of hydraulic conductivity (PLC) and the relative water loss (RWL) in woody stem axes with different P50, i.e. the water potential (Ψ) that causes 50% conductivity loss. Branches and saplings of temperate conifer (Picea abies, Larix decidua) and angiosperm species (Acer campestre, Fagus sylvatica, Populus x canescens, Populus tremula, Sorbus torminalis) and trunk wood of mature P. abies trees were analyzed. P50 was calculated from hydraulic measurements following bench top dehydration or air injection. RWL and PLC were fitted by linear, quadratic or cubic equations. Species‐ or age‐specific RWLs at P50 varied between 10 and 25% and P88, the Ψ that causes 88% conductivity loss, between 18 and 44%. P50 was predicted from the relationship between Ψ and the RWL. The predictive quality for P50 across species was almost 1:1 (r2 = 0.99). The approach presented allows thus reliable and fast prediction of PLC from RWL. Branches and saplings with high hydraulic vulnerability tended to have lower RWLs at P50 and at P88. The results are discussed with regard to the different water storage capacities in sapwood and survival strategies under drought stress. Potential applications are screening trees for drought sensitivity and a fast interpretation of diurnal, seasonal or drought induced changes in xylem water content upon their impact on conductivity loss. 相似文献
140.
Andrea Preitschopf Kongzhao Li David Sch?rghofer Katharina Kinslechner Birgit Schütz Ha Thi Thanh Pham Margit Rosner Gabor Jozsef Joo Clemens R?hrl Thomas Weichhart Herbert Stangl Gert Lubec Markus Hengstschl?ger Mario Mikula 《PloS one》2014,9(9)
Schwann cell development is hallmarked by the induction of a lipogenic profile. Here we used amniotic fluid stem (AFS) cells and focused on the mechanisms occurring during early steps of differentiation along the Schwann cell lineage. Therefore, we initiated Schwann cell differentiation in AFS cells and monitored as well as modulated the activity of the mechanistic target of rapamycin (mTOR) pathway, the major regulator of anabolic processes. Our results show that mTOR complex 1 (mTORC1) activity is essential for glial marker expression and expression of Sterol Regulatory Element-Binding Protein (SREBP) target genes. Moreover, SREBP target gene activation by statin treatment promoted lipogenic gene expression, induced mTORC1 activation and stimulated Schwann cell differentiation. To investigate mTORC1 downstream signaling we expressed a mutant S6K1, which subsequently induced the expression of the Schwann cell marker S100b, but did not affect lipogenic gene expression. This suggests that S6K1 dependent and independent pathways downstream of mTORC1 drive AFS cells to early Schwann cell differentiation and lipogenic gene expression. In conclusion our results propose that future strategies for peripheral nervous system regeneration will depend on ways to efficiently induce the mTORC1 pathway. 相似文献