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101.
Tamer M. A. Mohamed Delvac Oceandy Sukhpal Prehar Nasser Alatwi Zeinab Hegab Florence M. Baudoin Adam Pickard Aly O. Zaki Raja Nadif Elizabeth J. Cartwright Ludwig Neyses 《The Journal of biological chemistry》2009,284(18):12091-12098
The cardiac neuronal nitric-oxide synthase (nNOS) has been described as a
modulator of cardiac contractility. We have demonstrated previously that
isoform 4b of the sarcolemmal calcium pump (PMCA4b) binds to nNOS in the heart
and that this complex regulates β-adrenergic signal transmission in
vivo. Here, we investigated whether the nNOS-PMCA4b complex serves as a
specific signaling modulator in the heart. PMCA4b transgenic mice (PMCA4b-TG)
showed a significant reduction in nNOS and total NOS activities as well as in
cGMP levels in the heart compared with their wild type (WT) littermates. In
contrast, PMCA4b-TG hearts showed an elevation in cAMP levels compared with
the WT. Adult cardiomyocytes isolated from PMCA4b-TG mice demonstrated a
3-fold increase in Ser16 phospholamban (PLB) phosphorylation as
well as Ser22 and Ser23 cardiac troponin I (cTnI)
phosphorylation at base line compared with the WT. In addition, the relative
induction of PLB phosphorylation and cTnI phosphorylation following
isoproterenol treatment was severely reduced in PMCA4b-TG myocytes, explaining
the blunted physiological response to the β-adrenergic stimulation. In
keeping with the data from the transgenic animals, neonatal rat cardiomyocytes
overexpressing PMCA4b showed a significant reduction in nitric oxide and cGMP
levels. This was accompanied by an increase in cAMP levels, which led to an
increase in both PLB and cTnI phosphorylation at base line. Elevated cAMP
levels were likely due to the modulation of cardiac phosphodiesterase, which
determined the balance between cGMP and cAMP following PMCA4b overexpression.
In conclusion, these results showed that the nNOS-PMCA4b complex regulates
contractility via cAMP and phosphorylation of both PLB and cTnI.Neuronal nitric-oxide synthase
(nNOS)5 is involved in
a number of key processes in cardiomyocytes including calcium cycling
(1), the β-adrenergic
contractile response (2,
3), post-infarct left
ventricular remodeling (4), and
the regulation of redox equilibrium
(5). Moreover, a polymorphism
in an nNOS-interacting protein, CAPON, has been found to form a quantitative
trait for the determination of the QT interval in humans
(6), whereas a mutation in
α1-syntrophin (SNTA1), another interacting partner of nNOS, has been
associated with long QT syndrome
(7). The signaling events
downstream of the nNOS-CAPON
(8) and nNOS-SNTA1
(7) complexes, which are
responsible for mediating cardiac repolarization and sodium current
respectively, have been elucidated. The nNOS-containing protein complex is
therefore of immediate relevance to human pathology.In recent years, we have shown that the sarcolemmal calcium pump, which
ejects calcium to the extracellular compartment (reviewed in Refs.
9 and
10), is an important molecule
involved in signal regulation and transmission in the heart
(11). We have demonstrated
that isoform 4b of the sarcolemmal calcium pump (also known as PMCA4b for
plasma membrane calcium/calmodulin-dependent
ATPase 4b) modulates signaling through a tight molecular
interaction with nNOS, leading to the modulation of β-adrenergic
responsiveness in the heart
(12). However, the events
following signaling through the PMCA4b-nNOS complex remain unknown.In myocardial cells, nNOS has been localized to the sarcolemma
(13), sarcoplasmic reticulum
(2), and mitochondria
(14), and translocation
between compartments has been demonstrated
(15). It has been speculated
that these various localizations provide specificity to NO signaling, but the
exact mechanisms have yet to be elucidated. In this study, we show a mechanism
by which one fraction of nNOS serves highly specific functions through binding
to PMCA4b. As PMCA4b is confined to the sarcolemma and is a calcium pump, it
is the first identified protein to fulfill these aggregate functions. 1) It
acts as an anchoring protein; 2) it regulates nNOS activity; and 3) it
modulates a process at the plasma membrane, i.e. β-adrenergic
signaling. 相似文献
102.
In China, croplands account for a relatively large form of vegetation cover. Quantifying carbon dioxide exchange and understanding the environmental controls on carbon fluxes over croplands are critical in understanding regional carbon budgets and ecosystem behaviors. In this study, the net ecosystem exchange (NEE) at a winter wheat/summer maize rotation cropping site, representative of the main cropping system in the North China Plain, was continuously measured using the eddy covariance technique from 2005 to 2009. In order to interpret the abiotic factors regulating NEE, NEE was partitioned into gross primary production (GPP) and ecosystem respiration (Reco). Daytime Reco was extrapolated from the relationship between nighttime NEE and soil temperature under high turbulent conditions. GPP was then estimated by subtracting daytime NEE from the daytime estimates of Reco. Results show that the seasonal patterns of the temperature responses of Reco and light‐response parameters are closely related to the crop phenology. Daily Reco was highly dependent on both daily GPP and air temperature. Interannual variability showed that GPP and Reco were mainly controlled by temperature. Water availability also exerted a limit on Reco. The annual NEE was ?585 and ?533 g C m?2 for two seasons of 2006–2007 and 2007–2008, respectively, and the wheat field absorbed more carbon than the maize field. Thus, we concluded that this cropland was a strong carbon sink. However, when the grain harvest was taken into account, the wheat field was diminished into a weak carbon sink, whereas the maize field was converted into a weak carbon source. The observations showed that severe drought occurring during winter did not reduce wheat yield (or integrated NEE) when sufficient irrigation was carried out during spring. 相似文献
103.
RACE技术是一项扩增基因末端序列的新技术。该研究从牛BMP4基因出发,以牛软骨的RNA为模板,按照不同物种BMP4基因的相似性设计特异引物,运用PCR和RACE技术扩增并获得了特异片段,该片段经PCR、酶切和测序验证,证实所克隆序列为牛BMP4的3′端序列,包含有1170bp组成的开放读码框(ORF),编码389个氨基酸,3′非编码区121bp个核苷酸和poly(A)15。同源性分析结果表明,牛BMP4 cDNA最大开放读码框所推测的氨基酸序列与已知人、小鼠、大鼠、狗、羊和鸡等真核生物BMP4氨基酸序列进行比较,分别有94.5%、93.1%、91.9%、87.4%、94.2%、79%的同源性。这为克隆其他物种的BMP4基因提供了依据,同时牛骨形态发生蛋白的测序为我们更好的理解牛的生骨机理提供帮助。 相似文献
104.
105.
MÁRCIA FERNANDES DE AQUINO SANTOS JOSÉ RICARDO M. MERMUDES VERA MARIA MEDINA DA FONSECA 《Palaeontology》2011,54(4):807-814
Abstract: A specimen of Curculionidae (Curculioninae) is described as Arariperhinus monnei gen. et sp. nov. The specimen is preserved on a laminated limestone sample of the Crato Formation (Santana Group), Lower Cretaceous (Aptian–Albian), and was collected from a quarry near Nova Olinda, Chapada do Araripe, State of Ceará, Brazil. The genus is placed in the subfamily Curculioninae because of its strongly convex body and relatively slender rostrum, but mainly by its rounded eyes and lack of a prosternal sulcus and tibial spurs. The very prominent eyes in lateral view, a cylindrical rostrum and a straight posterior margin of ventrite II are strong indications that this fossil belongs to the tribe Anthonomini. However, the claws, which would resolve the exact placement of this fossil, are poorly preserved. Arariperhinus monnei gen. et sp. nov. is distinguishable by the combination of several characters and the first record of the family Curculionidae in the Santana Group; it is the oldest record of a member of the subfamily Curculioninae. 相似文献
106.
RICARDO CRUZ DE CARVALHO ANABELA BERNARDES DA SILVA RENATA SOARES ANDRÉ M. ALMEIDA ANA VARELA COELHO JORGE MARQUES DA SILVA CRISTINA BRANQUINHO 《Plant, cell & environment》2014,37(7):1499-1515
All bryophytes evolved desiccation tolerance (DT) mechanisms during the invasion of terrestrial habitats by early land plants. Are these DT mechanisms still present in bryophytes that colonize aquatic habitats? The aquatic bryophyte Fontinalis antipyretica Hedw. was subjected to two drying regimes and alterations in protein profiles and sucrose accumulation during dehydration and rehydration were investigated. Results show that during fast dehydration, there is very little variation in protein profiles, and upon rehydration proteins are leaked. On the other hand, slow dehydration induces changes in both dehydration and rehydration protein profiles, being similar to the protein profiles displayed by the terrestrial bryophytes Physcomitrella patens (Hedw.) Bruch and Schimp. and, to what is comparable with Syntrichia ruralis (Hedw.) F. Weber and D. Mohr. During dehydration there was a reduction in proteins associated with photosynthesis and the cytoskeleton, and an associated accumulation of proteins involved in sugar metabolism and plant defence mechanisms. Upon rehydration, protein accumulation patterns return to control values for both photosynthesis and cytoskeleton whereas proteins associated with sugar metabolism and defence proteins remain high. The current results suggest that bryophytes from different ecological adaptations may share common DT mechanisms. 相似文献
107.
Graham RD Jones Sabrina DA Koetsier 《The Clinical biochemist. Reviews / Australian Association of Clinical Biochemists》2014,35(4):243-250
Reference intervals are commonly considered to allow for between-laboratory bias. The RCPAQAP Liquid Serum Chemistry Program has collected data on laboratory measurements as well as reference intervals. This allows assessment of the between-laboratory variation in results, reference intervals and the information transmitted by the combination of these factors. For the majority of common chemistry analytes, the between-laboratory variation in reference intervals is greater than the variation in results. Additionally the reference interval variation is generally not related to bias between the results. Use of common reference intervals, either as an average of the current intervals in use, or the intervals proposed by the AACB Harmonisation Group, improved the variation seen in the information produced by different laboratories. 相似文献
108.
109.
Masochistic dreams, as defined by Beck (1967), are reportedly more prevalent among women and individuals with past or present depression. However, it is unclear whether these prevalence differences are a function of depressogenic personality traits or fluctuating mood symptoms. In the present study, 30 men and 30 women without histories of major depression slept two consecutive nights in a sleep laboratory and reported their dreams from each REM period on the second night. Dream content from this sample was compared to that of 60 depressed participants who were studied previously under the same protocol. Analyses did not support a heightened prevalence of masochistic dreams among women or depressed individuals. Interestingly, the masochistic dreams of the non-depressed sample were equally distributed across the night, whereas depressed individuals tend to report masochistic dreams closer to morning. This hypothesized pattern suggests that masochistic dreams may be pathognomic of depression in that their occurrence near the end of the night affects morning mood with negative dream residue. 相似文献
110.
上海环城林带景观美学评价及优化策略 总被引:3,自引:0,他引:3
选取上海环城林带7种植物群落,采用美景度评判法,从林内景观和林外景观2个空间层次和春、夏、秋、冬4个季节,应用数量化理论Ⅰ建立了美景度和各景观因子类目之间的景观评价与预测的多元回归模型,分析了群落的结构特征和季相特征对林内景观以及外貌特征对林外景观的影响,并提出相应的优化对策。结果表明:(1)群落结构特征对林内景观的影响主要因子为胸径(平均胸径和胸径变异系数)、郁闭度和疏透度。在春季,林内美景度随着树木胸径增大而增加;在夏季,郁闭度增大会提升林内美景度;在秋季,胸径变异小的群落具有更高的林内观赏性;在冬季,疏透度对林内景观美景度影响最大。(2)群落季相特征对林内景观的影响,在各季节表现亦不同。在春季,黄色、紫色等明度较高的色相和开花量适中的群落美景度最佳;在夏季,生长势好、林冠层变化小以及树干清晰度高的群落具较高的美景度,且观花可显著提高夏季林内美景度;在秋季,色彩越纯美景度越高;而在冬季,树皮颜色深的群落美景度高。(3)群落外貌特征对林外景观有显著影响,其中林冠线对林外景观美景度影响最大,其次为林缘线。具有起伏不大林冠线和自然流畅林缘线的植物群落美景度高。旨在通过对典型植被群落不同季相的美景度评价,对上海环城林带的群落景观进行定量的评价,进而为不同情景下的群落结构优化提出相应的对策,为城市森林的群落建构与管理提供科学依据。 相似文献