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排序方式: 共有1469条查询结果,搜索用时 31 毫秒
151.
Honarbakhsh M Villafane AA Ruhl I Sannino D Bini E 《Biotechnology and bioengineering》2012,109(7):1881-1886
Mesophilic glucuronidases are the most widely used reporters of gene expression in plants, but unsuitable as reporters in (hyper-)thermophiles due their insufficient thermal stability. Here we present the native 66.8 kDa thermostable β-glucuronidase of Sulfolobus solfataricus. The enzyme activity is characterized in a wide temperature range ideal for, but not limited to, in vivo genetic study of hyperthermophiles. As a proof of concept, we demonstrate its use as a reporter of gene expression in Sulfolobus, by monitoring a promoter fusion created with the β-glucuronidase coding gene gusB and a copper-responsive promoter. 相似文献
152.
Mantovani C Raimondo S Haneef MS Geuna S Terenghi G Shawcross SG Wiberg M 《Experimental cell research》2012,318(16):2034-2048
Adult mesenchymal stem cells have self-renewal and multiple differentiation potentials, and play important roles in regenerative medicine. However, their use may be limited by senescence or age of the donor, leading to changes in stem cell functionality. We investigated morphological, molecular and functional differences between bone marrow-derived (MSC) and adipose-derived (ASC) stem cells isolated from neonatal, young and old rats compared to Schwann cells from the same animals. Immunocytochemistry, RT-PCR, proliferation assays, western blotting and transmission electron microscopy were used to investigate expression of senescence markers. Undifferentiated and differentiated ASC and MSC from animals of different ages expressed Notch-2 at similar levels; protein-38 and protein-53 were present in all groups of cells with a trend towards increased levels in cells from older animals compared to those from neonatal and young rats. Following co-culture with adult neuronal cells, dMSC and dASC from animals of all ages elicited robust neurite outgrowth. Mitotracker® staining was consistent with ultrastructural changes seen in the mitochondria of cells from old rats, indicative of senescence. In conclusion, this study showed that although the cells from aged animals expressed markers of senescence, aged MSC and ASC differentiated into SC-like cells still retain potential to support axon regeneration. 相似文献
153.
Ghoochani A Shabani K Peymani M Ghaedi K Karamali F Karbalaei K Tanhaie S Salamian A Esmaeili A Valian-Borujeni S Hashemi M Nasr-Esfahani MH Baharvand H 《Differentiation; research in biological diversity》2012,83(1):60-67
Peroxisome proliferator activated receptor γ, belongs to PPARs, which exerts various metabolic functions including differentiation process. To testify the importance of PPARγ in neural differentiation of mouse embryonic stem cells (mESCs), its expression level was assessed. Data revealed an elevation in expression level of PPARγ when neural precursors (NPs) are formed upon retinoic acid treatment. Thus, involvement of PPARγ in two stages of neural differentiation of mESCs, during and post-NPs formation was examined by application of its agonist and antagonist. Our results indicated that PPARγ inactivation via treatment with GW9662 during NPs formation, reduced expression of neural precursor and neural (neuronal and astrocytes) markers. However, PPARγ inactivation by antagonist treatment post-NPs formation stage only decreased the expression of mature astrocyte marker (Gfap) suggesting that inactivation of PPARγ by antagonist decreased astrocyte differentiation. Here, we have demonstrated the stage dependent role of PPARγ modulation on neural differentiation of mESCs by retinoic acid treatment for the first time. 相似文献
154.
Bakhshandeh B Soleimani M Hafizi M Paylakhi SH Ghaemi N 《Molecular biology reports》2012,39(7):7569-7581
Cell-based approaches offer a potential therapeutic strategy for appropriate bone manufacturing. Capable of differentiating into multiple cell types especially osteoblasts spontaneously, unrestricted somatic stem cell (USSC) seems to be a suitable candidate. Recent studies have shown the involvement of microRNAs in several biological processes. miRNA microarray profiling was applied in order to identify the osteo-specific miRNA signature. Prior to this analysis, osteogenic commitment of osteoblasts was evaluated by measuring ALPase activity, biomineralization, specific staining and evaluation of some main osteogenic marker genes. To support our findings, various in silico explorations (for both putative targets and signaling pathways) and empirical analyses (miRNA transfections followed by qPCR of osteogenic indicators and ALPase activity measurement) were carried out. The function of GSK-3b inhibitor was also studied to investigate the role of WNT in osteogenesis. Transient modulation of multiple osteo-miRs (such as mir-199b, 1274a, 30b) with common targets (such as BMPR, TCFs, SMADs) as mediators of osteogenic pathways including cell-cell interactions, WNT and TGF-beta pathways, suggests a mechanism for rapid induction of the osteogenesis as an anti-miRNA therapy. The results of this research have identified the miRNA signature which regulates the osteogenesis mechanism in USSC. To conclude, our study reveals more details about the allocation of USSCs into osteogenic lineage through modulatory effect of miRNAs on targets and pathways required for creating a tissue-specific phenotype and may aid in future clinical interventions. 相似文献
155.
In tropical and subtropical regions of the world, parasitic diseases are major obstacle in the health and ultimately overall
performance of animals. Cattle express heritable, contrasting phenotypes when exposed to ticks depicting genetic nature of
trait. IFN-γ is one of the most reported genes critical for innate and adaptive immunity against viral and intracellular infections.
To identify its role in resistance for ectoparasite especially tick, genetic characterization of this gene was done in resistant
and susceptible animals of Sahiwal cattle (n = 95) and Friesian (n = 92). Nine Polymorphisms were identified, three of them were found in exonic region. One out of nine variants was being
reported previously (ss82716193) and was confirmed in Pakistani Sahiwal cattle population as well. Single site analysis of
each variant depicted their significance in tick resistant and tick susceptible groups (P < 0.05). The associations using haplotypes were more informative than for single markers. Eighteen different haplotypes resulting
from nine polymorphic sites were used in construction of maximum parsimony tree which categorized resistant and susceptible
animals in two clades. Genetic markers identified in this study can be useful in future breeding selection programs against
tick resistance. 相似文献
156.
Månsson LE Montero M Zarepour M Bergstrom KS Ma C Huang T Man C Grassl GA Vallance BA 《American journal of physiology. Gastrointestinal and liver physiology》2012,303(3):G311-G323
Salmonella enterica serovar Typhimurium is a clinically important gram-negative, enteric bacterial pathogen that activates several Toll-like receptors (TLRs). While TLR signaling through the adaptor protein MyD88 has been shown to promote inflammation and host defense against the systemic spread of S. Typhimurium, curiously, its role in the host response against S. Typhimurium within the mammalian gastrointestinal (GI) tract is less clear. We therefore used the recently described Salmonella-induced enterocolitis and fibrosis model: wild-type (WT) and MyD88-deficient (MyD88(-/-)) mice pretreated with streptomycin and then orally infected with the ΔaroA vaccine strain of S. Typhimurium. Tissues were analyzed for bacterial colonization, inflammation, and epithelial damage, while fibrosis was assessed by collagen quantification and Masson's trichrome staining. WT and MyD88(-/-) mice carried similar intestinal pathogen burdens to postinfection day 21. Infection of WT mice led to acute mucosal and submucosal inflammation and edema, as well as significant intestinal epithelial damage and proliferation, leading to widespread goblet cell depletion. Impressive collagen deposition in the WT intestine was also evident in the submucosa at postinfection days 7 and 21, with fibrotic regions rich in fibroblasts and collagen. While infected MyD88(-/-) mice showed levels of submucosal inflammation and edema similar to WT mice, they were impaired in the development of mucosal inflammation, along with infection-induced epithelial damage, proliferation, and goblet cell depletion. MyD88(-/-) mouse tissues also had fewer submucosal fibroblasts and 60% less collagen. We noted that cyclooxygenase (Cox)-2 expression was MyD88-dependent, with numerous Cox-2-positive cells identified in fibrotic regions of WT mice at postinfection day 7, but not in MyD88(-/-) mice. Treatment of WT mice with the Cox-2 inhibitor rofecoxib (20 mg/kg) significantly reduced fibroblast numbers and collagen levels without altering colitis severity. In conclusion, MyD88 and Cox-2 signaling play roles in intestinal fibrosis during Salmonella-induced enterocolitis. 相似文献
157.
Although it is well-known that AMPA receptors are involved in spatial learning and memory, published data on GluR3 and GluR4 are limited. Moreover, there is no information about GluR3 and GluR4 receptor complex levels in spatial memory training. It was therefore the aim of the study to determine the above-mentioned receptor levels following training in the Multiple T-Maze (MTM). Results from the MTM and hippocampal membrane proteins from C57BL/6J mice were taken from an own previous study and GluR3 and GluR4 receptor complexes were run on blue native gel electrophoresis followed by immunoblotting and quantification of bands. Subsequently, GluR3 and GluR4 were identified under denaturing conditions from two-dimensional gels by mass spectrometry (nano-LC-ESI-MS/MS). Hippocampal levels of GluR3 containing complexes (apparent molecular weight between 480 and 720) were decreased while GluR4 containing complexes (apparent molecular weight between 480 and 720) were increased. GluR4 complex levels in trained mice were correlating with latency and speed. Mass spectrometry unambiguously identified the two receptor subunits. The findings show that GluR3 and GluR4 may have different functions in the processes of spatial memory training in the MTM and indeed, different neurobiological functions of the two receptor subunits have been already reported. GluR3 and GluR4 receptor complex rather than subunit levels are paralleling training in the MTM and GluR4 complex levels were even linked to memory training, which may be of relevance for understanding molecular memory processes, interpretation of previous work or for design of future AMPA receptor studies. 相似文献
158.
Kadkhodaee M Mikaeili S Zahmatkesh M Golab F Seifi B Arab HA Shams S Mahdavi-Mazdeh M 《General physiology and biophysics》2012,31(2):195-202
Liver ischemia/reperfusion (IR) injury is a complex phenomenon that may cause local as well as remote organ injuries. Reactive oxygen species (ROS) along with many pro- and anti- inflammatory cytokines are implicated in the development of organ injury. The renal functional, histological, oxidative stress and inflammatory indices were studied during a short and a longer period of liver IR. Rats were subjected to either sham operation or 90 min partial liver ischemia followed by 4 or 24 h of reperfusion. Serum ALT, AST, ALK and LDH levels, BUN and creatinine, renal MDA level, SOD and catalase activities were evaluated as well as serum IL-6 and IL-10 concentrations along with renal histological evaluation. Ninety minutes liver ischemia /4 h reperfusion caused an increase in BUN and renal MDA levels and a decrease in SOD and catalase activities. It also caused an increase in serum IL-6 and IL-10 levels. 24 h liver reperfusion resulted in a reduction in BUN levels and lower oxidative damages demonstrated by a decrease in renal MDA levels and an increase in renal SOD and catalase activities comparing to 4 h reperfusion group. Evaluations indicated improvement in histology such as less cytoplasmic vacuolation and lower tubular debris. Serum inflammatory indices (IL-6 and IL-10 levels) were also reduced. This study showed that liver IR damage causes renal injury including functional, inflammatory and oxidative status changes. The remote kidney damage was then improved by continuing reperfusion from 4 to 24 h. 相似文献
159.
It is believed that ROS-induced oxidative stress triggers numerous signaling pathways which are involved in neurodegenerative
diseases, including Alzheimer’s disease. To find the effective drugs for neurodegenerative diseases, the deep delve into molecular
mechanisms underlie these diseases is necessary. In the current study, we investigated the effects of flavonoid baicalein
on H2O2-induced oxidative stress and cell death in SK-N-MC cells. Our results revealed that the treatment of SK-N-MC cells with H2O2 led to a decrease in cell viability through phosphorylation and activation of extracellular signal-regulated kinases (ERKs)
and c-Jun N-terminal kinases (JNKs) pathways followed by increase in Bax/Bcl2 ratio and initiation of caspase-dependent apoptotic
pathways. In addition, our results showed that the exposure of SK-N-MC cells to H2O2 ended up in reduction of glutathione (GSH) levels of SK-N-MC cells via JNK/ERK-mediated down-regulation of γ-glutamyl-cysteine
synthetase (γ-GCS) expression. Our results demonstrated that flavonoid baicalein protected against H2O2-induced cell death by inhibition of JNK/ERK pathways activation and other key molecules in apoptotic pathways, including
blockage of Bax and caspase-9 activation, induction of Bcl-2 expression and prevention of cell death. Baicalein supported
intracellular defense mechanisms through maintaining GSH levels in SK-N-MC cells by the removal of inhibition effects of JNK/ERK
pathways from γ-GCS expression. In addition, baicalein attenuated lipid and protein peroxidation and intracellular reactive
oxygen species in SK-N-MC cells. In accordance with these observations, baicalein can be a promising candidate in antioxidant
therapy and designing of natural-based drug for ROS-induced neurodegenerative disorders. 相似文献
160.