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排序方式: 共有1246条查询结果,搜索用时 15 毫秒
91.
Song HW Cauffman K Chan AP Zhou Y King ML Etkin LD Kloc M 《Differentiation; research in biological diversity》2007,75(6):519-528
The early development of metazoans is mainly regulated by differential translation and localization of maternal mRNAs in the embryo. In general, these processes are orchestrated by RNA-binding proteins interacting with specific sequence motifs in the 3'-untranslated region (UTR) of their target RNAs. Hermes is an RNA-binding protein, which contains a single RNA recognition motif (RRM) and is found in various vertebrate species from fish to human. In Xenopus laevis, Hermes mRNA and protein are localized in the vegetal region of oocytes. A subpopulation of Hermes protein is concentrated in a specific structure in the vegetal cortex, called the germ plasm (believed to contain determinants of the germ cell fate) where Hermes protein co-localizes with Xcat2 and RINGO/Spy mRNAs. The level of total Hermes protein decreases during maturation. The precocious depletion of Hermes protein by injection of Hermes antisense morpholino oligonucleotide (HE-MO) accelerates the process of maturation and results in cleavage defects in vegetal blastomeres of the embryo. It is known that several maternal mRNAs including RINGO/Spy and Mos are regulated at the translational level during meiotic maturation and early cleavage in Xenopus. The ectopic expression of RINGO/Spy or Mos causes resumption of meiotic maturation and cleavage arrests, which resemble the loss of Hermes phenotypes. We found that the injection of HE-MO enhances the acceleration of maturation caused by the injection of RINGO/Spy mRNA, and that Hermes protein is present as mRNP complex containing RINGO/Spy, Mos, and Xcat2 mRNAs in vivo. We propose that as an RNA-binding protein, Hermes may be involved in maturation, cleavage events at the vegetal pole and germ cell development by negatively regulating the expression of RINGO/Spy, Mos, and Xcat2 mRNAs. 相似文献
92.
Omar HH Humphries JE Larsen MJ Kubiak TM Geary TG Maule AG Kimber MJ Day TA 《International journal for parasitology》2007,37(7):725-733
We report the characterisation of the first neuropeptide receptor from the phylum Platyhelminthes, an early-diverging phylum which includes a number of important human and veterinary parasites. The G protein-coupled receptor (GPCR) was identified from the model flatworm Girardia tigrina (Tricladida: Dugesiidae) based on the presence of motifs widely conserved amongst GPCRs. In two different assays utilising heterologous expression in Chinese hamster ovary cells, the Girardia GPCR was most potently activated by neuropeptides from the FMRFamide-like peptide class. The most potent platyhelminth neuropeptide in both assays was GYIRFamide, a FMRFamide-like peptide known to be present in G. tigrina. There was no activation by neuropeptide Fs, another class of flatworm neuropeptides. Also active were FMRFamide-like peptides derived from other phyla but not known to be present in any platyhelminth. Most potent among these were nematode neuropeptides encoded by the Caenorhabditis elegans flp-1 gene which share a PNFLRFamide carboxy terminal motif. The ability of nematode peptides to stimulate a platyhelminth receptor demonstrates a degree of structural conservation between FMRFamide-like peptide receptors from these two distinct, distant phyla which contain parasitic worms. 相似文献
93.
Ducsay CA Hyatt K Mlynarczyk M Root BK Kaushal KM Myers DA 《American journal of physiology. Regulatory, integrative and comparative physiology》2007,293(5):R1997-R2005
We previously communicated that long-term hypoxia (LTH) resulted in a selective reduction in plasma epinephrine following acute stress in fetal sheep. The present study tested the hypothesis that LTH selectively reduces adrenomedullary expression of phenylethanolamine-N-methyltransferase (PNMT), the rate-limiting enzyme for epinephrine synthesis. We also examined the effect of LTH on adrenomedullary nicotinic, muscarinic, and glucocorticoid receptor (GR) expression. Ewes were maintained at high altitude (3,820 m) from 30 to 138 days gestation (dGA); adrenomedullary tissue was collected from LTH and age-matched, normoxic control fetuses at 139-141 dGA. Contrary to our hypothesis, in addition to PNMT, adrenomedullary expression (mRNA, protein) of tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH) were reduced in the LTH fetus. Immunocytochemistry indicated that TH and DBH expression was lower throughout the medulla, while PNMT appeared to reflect a reduction in PNMT-expressing cells. Nicotinic receptor alpha 1, 2, 3, 5, 6, 7, beta 1, 2, and 4 subunits were expressed in the medulla of LTH and control fetuses. Messenger RNA for alpha 1 and 7 and beta 1 and 2 subunits was lower in LTH fetuses. Muscarinic receptors M1, M2, and M3 as well as the GR were also expressed, and no differences were noted between groups. In summary, LTH in fetal sheep has a profound effect on expression of key enzymes mediating adrenomedullary catecholamine synthesis. Further, LTH impacts nicotinic receptor subunit expression potentially altering cholinergic neurotransmission within the medulla. These findings have important implications regarding fetal cardiovascular and metabolic responses to stress in the LTH fetus. 相似文献
94.
95.
Lysigenous aerenchyma formation in Arabidopsis is controlled by LESION SIMULATING DISEASE1 总被引:1,自引:0,他引:1
Mühlenbock P Plaszczyca M Plaszczyca M Mellerowicz E Karpinski S 《The Plant cell》2007,19(11):3819-3830
Aerenchyma tissues form gas-conducting tubes that provide roots with oxygen under hypoxic conditions. Although aerenchyma have received considerable attention in Zea mays, the signaling events and genes controlling aerenchyma induction remain elusive. Here, we show that Arabidopsis thaliana hypocotyls form lysigenous aerenchyma in response to hypoxia and that this process involves H(2)O(2) and ethylene signaling. By studying Arabidopsis mutants that are deregulated for excess light acclimation, cell death, and defense responses, we find that the formation of lysigenous aerenchyma depends on the plant defense regulators LESION SIMULATING DISEASE1 (LSD1), ENHANCED DISEASE SUSCEPIBILITY1 (EDS1), and PHYTOALEXIN DEFICIENT4 (PAD4) that operate upstream of ethylene and reactive oxygen species production. The obtained results indicate that programmed cell death of lysigenous aerenchyma in hypocotyls occurs in a similar but independent manner from the foliar programmed cell death. Thus, the induction of aerenchyma is subject to a genetic and tissue-specific program. The data lead us to conclude that the balanced activities of LSD1, EDS1, and PAD4 regulate lysigenous aerenchyma formation in response to hypoxia. 相似文献
96.
97.
The pleiotropic effects of creatine (Cr) are based mostly on the functions of the enzyme creatine kinase (CK) and its high-energy
product phosphocreatine (PCr). Multidisciplinary studies have established molecular, cellular, organ and somatic functions
of the CK/PCr system, in particular for cells and tissues with high and intermittent energy fluctuations. These studies include
tissue-specific expression and subcellular localization of CK isoforms, high-resolution molecular structures and structure–function
relationships, transgenic CK abrogation and reverse genetic approaches. Three energy-related physiological principles emerge,
namely that the CK/PCr systems functions as (a) an immediately available temporal energy buffer, (b) a spatial energy buffer
or intracellular energy transport system (the CK/PCr energy shuttle or circuit) and (c) a metabolic regulator. The CK/PCr
energy shuttle connects sites of ATP production (glycolysis and mitochondrial oxidative phosphorylation) with subcellular
sites of ATP utilization (ATPases). Thus, diffusion limitations of ADP and ATP are overcome by PCr/Cr shuttling, as most clearly
seen in polar cells such as spermatozoa, retina photoreceptor cells and sensory hair bundles of the inner ear. The CK/PCr
system relies on the close exchange of substrates and products between CK isoforms and ATP-generating or -consuming processes.
Mitochondrial CK in the mitochondrial outer compartment, for example, is tightly coupled to ATP export via adenine nucleotide
transporter or carrier (ANT) and thus ATP-synthesis and respiratory chain activity, releasing PCr into the cytosol. This coupling
also reduces formation of reactive oxygen species (ROS) and inhibits mitochondrial permeability transition, an early event
in apoptosis. Cr itself may also act as a direct and/or indirect anti-oxidant, while PCr can interact with and protect cellular
membranes. Collectively, these factors may well explain the beneficial effects of Cr supplementation. The stimulating effects
of Cr for muscle and bone growth and maintenance, and especially in neuroprotection, are now recognized and the first clinical
studies are underway. Novel socio-economically relevant applications of Cr supplementation are emerging, e.g. for senior people,
intensive care units and dialysis patients, who are notoriously Cr-depleted. Also, Cr will likely be beneficial for the healthy
development of premature infants, who after separation from the placenta depend on external Cr. Cr supplementation of pregnant
and lactating women, as well as of babies and infants are likely to be of benefit for child development. Last but not least,
Cr harbours a global ecological potential as an additive for animal feed, replacing meat- and fish meal for animal (poultry
and swine) and fish aqua farming. This may help to alleviate human starvation and at the same time prevent over-fishing of
oceans. 相似文献
98.
Satoh M Krzyszczak ME Li Y Ceribelli A Ross SJ Chan EK Segal MS Bubb MR Sobel ES Reeves WH 《Arthritis research & therapy》2011,13(3):R73
Introduction
The presence of anti-topoisomerase I (topo I) antibodies is a classic scleroderma (SSc) marker presumably associated with a unique clinical subset. Here the clinical association of anti-topo I was reevaluated in unselected patients seen in a rheumatology clinic setting. 相似文献99.
Miller M Dreisbach A Otto A Becher D Bernhardt J Hecker M Peppelenbosch MP van Dijl JM 《Journal of proteome research》2011,10(9):4018-4032
Staphylococcus aureus is a dangerous opportunistic human pathogen that causes serious invasive diseases when it reaches the bloodstream. Recent studies have shown that S. aureus is highly resistant to killing by professional phagocytes and that such cells even provide a favorable environment for intracellular survival of S. aureus. Importantly, the reciprocal interactions between phagocytes and S. aureus have remained largely elusive. Here we have employed kinase profiling to define the nature and time resolution of the human THP-1 macrophage response toward S. aureus and proteomics to identify the response of S. aureus toward macrophages. The results of these studies reveal major macrophage signaling pathways triggered by S. aureus and proteomic signatures of the responses of S. aureus to macrophages. We also identify human proteins bound to S. aureus that have potential roles in bacterial killing and internalization. Most noticeably, our observations challenge the classical concept that macrophage responses are mainly mediated through Toll-like receptor 2 and NF-κB signaling and highlight the important role of the stress-activated MAP kinase signaling in orchestrating the host defense. 相似文献
100.
Malgorzata Monika Stanczyk 《Reports of Practical Oncology and Radiotherapy》2011,16(5):170-172
The purpose of this paper is to show some aspects of music therapy application in cancer care and to present the integration of music therapy program into a continuous supportive cancer care for inpatients. A cancer diagnosis is one of the most feared and serious life events that causes stress in individuals and families. Cancer disrupts social, physical and emotional well-being and results in a range of emotions, including anger, fear, sadness, guilt, embarrassment and shame. Music therapy is a part of a complementary medicine program in supportive cancer care which accompanies medical treatment. There are many benefits of music therapy for cancer patients—interactive music therapy techniques (instrumental improvisation, singing) as well as receptive music therapy techniques (listening to recorded or live music, music and imaginary) can be used to improve mood, decrease stress, pain, anxiety level and enhance relaxation. Music therapy is an effective form of supporting cancer care for patients during the treatment process. It may be also basic for planning effective programs of rehabilitation to promote wellness, improve physical and emotional well-being and the quality of life. 相似文献