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151.
Da Shi Su Xu Jaylyn Waddell Susanna Scafidi Steven Roys Rao P. Gullapalli Mary C. McKenna 《Journal of neurochemistry》2012,123(6):971-981
Fragile X syndrome (FXS) is the most common form of inherited mental retardation and is studied in the Fmr1 knockout (KO) mouse, which models both the anatomical and behavioral changes observed in FXS patients. In vitro studies have shown many alterations in synaptic plasticity and increased density of immature dendritic spines in the hippocampus, a region involved in learning and memory. In this study, magnetic resonance imaging (MRI) and 1H magnetic resonance spectroscopy (MRS) were used to determine in vivo longitudinal changes in volume and metabolites in the hippocampus during the critical period of early myelination and synaptogenesis at post‐natal days (PND) 18, 21, and 30 in Fmr1 KO mice compared with wild‐type (WT) controls. MRI demonstrated an increase in volume of the hippocampus in the Fmr1 KO mouse compared with controls. MRS revealed significant developmental changes in the ratios of hippocampal metabolites N‐acetylaspartate (NAA), myo‐inositol (Ins), and taurine to total creatine (tCr) in Fmr1 KO mice compared with WT controls. Ins was decreased at PND 30, and taurine was increased at all ages studied in Fmr1 KO mice compared with controls. An imbalance of brain metabolites in the hippocampus of Fmr1 KO mice during the critical developmental period of synaptogenesis and early myelination could have long‐lasting effects that adversely affect brain development and contribute to ongoing alterations in brain function. 相似文献
152.
C Daleno A Piralla A Scala F Baldanti V Usonis N Principi S Esposito 《Journal of virology》2012,86(19):10888-10889
The new enterovirus C-117 strain belongs to the human enterovirus C species in the Picornaviridae family. We describe the characterization of the complete genome of this strain identified in a respiratory specimen of a child enrolled in the Community-Acquired Pneumonia Pediatric Research Initiative (CAP-PRI) study evaluating the etiology of community-acquired pneumonia (CAP). 相似文献
153.
Phuong T. Y. Dinh Marissa Roldan Susanna Leung Michael T. McManus 《Plant Growth Regulation》2012,66(2):179-190
The influence of P-supply on root system architecture (primary root length, number and total length of lateral roots) through
the effects of ethylene (ACC) and auxin [1-naphthylacetic acid (NAA)] has been examined in the legume white clover (Trifolium repens L.). Higher concentrations (1 and 10 μM) of ACC and NAA (100 nM) inhibited growth, while lower concentrations (100 nM ACC,
5 nM NAA) either had no effect or stimulated growth in P-sufficient (1 mM Pi) roots. In response to low (10 μM) P, a stimulation
of primary root growth, number of lateral roots and mean length of lateral roots was observed, while a super-stimulation of
these growth parameters occurred in response to subsequent 100 nM ACC treatment suggesting that the low P treatment increased
the sensitivity of the roots to ethylene. Examination of the primary roots of DR5p::GUS transformants suggests that this change in sensitivity induced by low P occurs through the promotion of auxin signalling/transport
to the root apex. These results are discussed in terms of the role of ethylene and the significance of changes in sensitivity
to the hormone in modulating root system architecture in response to low P-supply. 相似文献
154.
Nik-Zainal S Alexandrov LB Wedge DC Van Loo P Greenman CD Raine K Jones D Hinton J Marshall J Stebbings LA Menzies A Martin S Leung K Chen L Leroy C Ramakrishna M Rance R Lau KW Mudie LJ Varela I McBride DJ Bignell GR Cooke SL Shlien A Gamble J Whitmore I Maddison M Tarpey PS Davies HR Papaemmanuil E Stephens PJ McLaren S Butler AP Teague JW Jönsson G Garber JE Silver D Miron P Fatima A Boyault S Langerød A Tutt A Martens JW Aparicio SA Borg Å Salomon AV Thomas G Børresen-Dale AL Richardson AL 《Cell》2012,149(5):979-993
155.
Lucia Andreini Raffaella Viti Susanna Bartolini David Ruiz José Egea Jose Antonio Campoy 《Trees - Structure and Function》2012,26(3):919-928
Environmental and climatic conditions affect the flower bud growth, flowering and yield performance of fruit species. Temperature
and water availability appear to be important factors for temperate fruit trees in mild climates. The aim of this research
was to study the involvement of temperature regime on biological processes, such as xylem differentiation and dormancy evolution,
in apricot flower buds (Prunus armeniaca L.). Over 3 consecutive years, biological and anatomical investigations were carried out in Tuscany (Italy) and Murcia (Spain)
on two cultivars characterized by a different chilling requirement (CR): Currot, a traditional Spanish cultivar with a very
low CR, and Stark Early Orange (SEO), a North American cultivar with a very high CR. Currot had a regular bearing, and was
characterized by a synchronism between endodormancy release and xylem differentiation. On the other hand, SEO showed an irregular
flower bud growth leading to flowering and fruit-set failure, even with a high level of chilling accumulation. No relationship
was found in SEO between xylem development and flower bud growth reactivation. The de-synchronism between these processes
could determine the poor adaptability to different environmental areas of SEO cultivar, and its very high CR is not the main
hypothesised cause of the altered flower bud development. 相似文献
156.
Sauret-Güeto S Calder G Harberd NP 《The Plant journal : for cell and molecular biology》2012,69(4):628-639
The phytohormone gibberellin (GA) promotes plant growth by stimulating cellular expansion. Whilst it is known that GA acts by opposing the growth-repressing effects of DELLA proteins, it is not known how these events promote cellular expansion. Here we present a time-lapse analysis of the effects of a single pulse of GA on the growth of Arabidopsis hypocotyls. Our analyses permit kinetic resolution of the transient growth effects of GA on expanding cells. We show that pulsed application of GA to the relatively slowly growing cells of the unexpanded light-grown Arabidopsis hypocotyl results in a transient burst of anisotropic cellular growth. This burst, and the subsequent restoration of initial cellular elongation rates, occurred respectively following the degradation and subsequent reappearance of a GFP-tagged DELLA (GFP-RGA). In addition, we used a GFP-tagged α-tubulin 6 (GFP-TUA6) to visualise the behaviour of microtubules (MTs) on the outer tangential wall (OTW) of epidermal cells. In contrast to some current hypotheses concerning the effect of GA on MTs, we show that the GA-induced boost of hypocotyl cell elongation rate is not dependent upon the maintenance of transverse orientation of the OTW MTs. This confirms that transverse alignment of outer face MTs is not necessary to maintain rapid elongation rates of light-grown hypocotyls. Together with future studies on MT dynamics in other faces of epidermal cells and in cells deeper within the hypocotyl, our observations advance understanding of the mechanisms by which GA promotes plant cell and organ growth. 相似文献
157.
Differential superoxide dismutase expression in ryegrass cultivars in response to short term aluminium stress 总被引:3,自引:0,他引:3
Cartes Paula McManus Michael Wulff-Zottele Cristián Leung Susanna Gutiérrez-Moraga Ana Mora María de la Luz 《Plant and Soil》2012,352(1-2):353-362
Background and aims
Saline soils limit plant production worldwide through osmotic stress, specific-ion toxicities, and nutritional imbalances.Methods
The ability of Ca2+ and K+ to alleviate toxicities of Na+ and Mg2+ was examined using 89 treatments in short-term (48 h) solution culture studies for cowpea (Vigna unguiculata (L.) Walp.) roots. Root elongation was related to ionic activities at the outer surface of the root plasma membrane.Results
The addition of K+ was found to alleviate the toxic effects of Na+, and supplemental Ca2+ improved growth further in these partially-alleviated solutions where K+ was present. Therefore, Na+ appears to interfere with K+ metabolism, and Ca2+ reduces this interference. Interestingly, the ability of Ca2+ to improve K-alleviation of Na+ toxicity is non-specific, with Mg2+ having a similar effect. In contrast, the addition of Ca2+ to Na-toxic solutions in the absence of K+ did not improve growth, suggesting that Ca2+ does not directly reduce Na+ toxicity in these short-term studies (for example, by reducing Na+ uptake) when supplied at non-deficient levels. Finally, K+ did not alleviate Mg2+ toxicity, suggesting that Mg2+ is toxic by a different mechanism to Na+.Conclusions
Examination of how the toxic effects of salinity are alleviated provides clues as to the underlying mechanisms by which growth is reduced. 相似文献158.
159.
Ana Marina Ferreira Piergiorgio Gentile Susanna Sartori Cristina Pagliano Chiara Cabrele Valeria Chiono Prof. Gianluca Ciardelli 《Biotechnology journal》2012,7(11):1386-1394
Type I collagen has been extensively exploited as a biomaterial for biomedical applications and drug delivery; however, small molecular alterations occurring during the isolation procedure and its interaction with residual bone extracellular matrix molecules or proteins might affect the overall material biocompatibility and performance. The aim of the current work is to study the potential alterations in collagen properties and organization associated with the absence of proteoglycans, which mimic pathological conditions associated with age‐related diseases. A new approach for evaluating the effect of proteoglycans on the properties of isolated type I collagen from the bone matrix is described. Additional treatment with guanidine hydrochloride was introduced to remove residual proteoglycans from the collagen matrix. The properties of the isolated collagen with/without guanidine hydrochloride treatment were investigated and compared with a commercial rabbit collagen as control. We demonstrate that the absence of proteoglycans in the isolated type I collagen affects its thermal properties, the extraction into its native structure, and its ability to hydrate and self‐assemble into fibers. The fine control and tuning of all these features, linked to the absence of non‐collagenous proteins as proteoglycans, offer the possibility of designing new strategies and biomaterials with advanced biomimetic properties aimed at regenerating bone tissue in the case of fragility and/or defects. 相似文献
160.