共查询到20条相似文献,搜索用时 31 毫秒
1.
Nav1.5 dysfunctions are commonly linked to rhythms disturbances that include type 3 long QT syndrome (LQT3), Brugada syndrome (BrS), sick sinus syndrome (SSS) and conduction defects. Recently, this channel protein has been also linked to structural heart diseases such as dilated cardiomyopathy (DCM). 相似文献
2.
It is commonly known that calcium promotes NO3
- uptake in many crop species. However, calcium enhancement of NH4
+ uptake by plants has received little attention. This study aimed to evaluate the effect of Ca supplements on NH4
+ uptake and plant growth in solution cultured rice. Supplemental Ca applied at vegetative and reproductive phases of plant
ontogeny tended to stimulate NH4
+ absorption, and accordingly resulted in a better straw and grain yield. However, excessively supplied Ca (400 ppm) was detrimental
to plant growth. Increases in straw and grain yield observed at Ca levels up to 300 ppm were linked to the Ca-enhanced activities
of glutamine synthetase (GS), glutamate synthase (GOGAT), and ribulose 1, 5-bisphosphate carboxylase/oxygenase (Rubisco). 相似文献
3.
Aim
Many cancers originate and flourish in a prolonged inflammatory environment. Our aim is to understand the mechanisms of how the pathway of prostaglandin E2 (PGE2) biosynthesis and signaling can promote cancer growth in inflammatory environment at cellular and animal model levels.Main methods
In this study, a chronic inflammation pathway was mimicked with a stable cell line that over-expressed a novel human enzyme consisting of cyclooxygenase isoform-2 (COX-2) linked to microsomal (PGE2 synthase-1 (mPGES-1)) for the overproduction of pathogenic PGE2. This PGE2-producing cell line was co-cultured and co-implanted with three human cancer cell lines including prostate, lung, and colon cancers in vitro and in vivo, respectively.Key findings
Increases in cell doubling rates for the three cancer cell types in the presence of the PGE2-producing cell line were clearly observed. In addition, one of the four human PGE2 subtype receptors, EP1, was used as a model to identify PGE2-signaling involved in promoting the cancer cell growth. This finding was further proven in vivo by co-implanting the PGE2-producing cells line and the EP1-positive cancer cells into the immune deficient mice, after that, it was observed that the PGE2-producing cells promoted all three types of cancer formation in the mice.Significance
This study clearly demonstrated that the human COX-2 linked to mPGES-1 is a pathway that, when mediated by the EP, is linked to promoting cancer growth in a chronic inflammatory environment. The identified pathway could be used as a novel target for developing and advancing anti-inflammation and anti-cancer interventions. 相似文献4.
《Electromagnetic biology and medicine》2013,32(2-3):87-101
This study examines the response of different time constant 7.5 Hz pulsed electromagnetic field (PEMF) stimulation on rat osteoblasts and tries to determine the shortest exposure time to the selected time constant PEMF that is necessary to increase cell viability in vitro. We use an in vitro rat osteoblast model to investigate, for different periods of time (1, 2, or 3 days), rat osteoblasts to 7.5 Hz PEMF of different time constants (694, 432, and 268 µsec) or exposure time (20 min, 1, 3, 9, and 24 hr) and have evaluated the field's effects on the cell viability by colorimetric tetrazolium (MTT) assay and PGE2 concentrations by enzyme‐linked immunosorbent assay (ELISA). It was shown that time constant was not the dominant parameter affecting osteoblast growth, and a short time exposure of PEMF 20 min/day could increase cell viability and PGE2 secretion significantly. 相似文献
5.
F. A. Carvalho J. P. Lopes de Almeida T. Freitas-Santos C. Saldanha 《The Journal of membrane biology》2009,228(2):89-97
Circulating acetylcholine, substrate of membrane acetylcholinesterase (AChE), is known to enhance the band 3 protein degree
of phosphorylation. The purpose of this study was to verify whether the band 3 phosphorylation status is associated with a
G protein and whether it is an influent factor on AChE enzyme activity. From blood samples of healthy donors, erythrocyte
suspensions were prepared and incubated with AChE substrate (acetylcholine) and inhibitor (velnacrine), along with protein
tyrosine kinase (PTK) and tyrosine phosphatase (PTP) inhibitors. AChE activity was determined by spectrophotometry and extract
samples were analyzed by western blotting using primary antibodies to different G protein subunits. Our results with phosphorylated
band 3 (PTP inhibitor) show an increase in erythrocyte AChE (p < 0.0001). A dephosphorylated band 3 state (PTK inhibitor) shows a significant decrease. We identified a potential linkage
of protein subunits Gαi1/2 and Gβ with band 3 protein. Gαi1/2 and Gβ may be linked to the band 3 C-terminal site. Gαi1/2 is associated with the band 3 N-terminal domain, except for the control and ACh aliquots. Gβ is associated with both phosphorylated and dephosphorylated band 3 in the presence of velnacrine. We conclude that an erythrocyte
G protein with subunits Gαi1/2 and Gβ is associated with band 3. AChE depends on the degree of band 3 phosphorylation and its association with Gαi1/2 and Gβ. 相似文献
6.
Enhanced expression of transforming growth factor-β1(TGF-β1) demonstrated in human colonic mucosa of patients with ulcerative colitis (UC), indicates its possible significance in the pathogenesis of this disease. The aim of this study was to evaluate plasma TGF-β1concentration in patients with different degrees of colonic mucosal injury, as a possible indicator of ulcerative colitis activity. TGF-β1concentration was measured with an enzyme immunoassay (EIA) in plasma of 45 patients with endoscopically confirmed UC. Values observed in UC patients (40.5±15.9 ng/ml) were significantly higher than in healthy people (18.3±11.6 ng/ml) and higher than in patients with irritable colon syndrome (ICS), (20.5±13.6 ng/ml). The highest plasma TGF-β1(58.6±112.1 ng/ml) was in patients with the severe UC course. TGF-β1level analysed in all UC patients revealed significant positive correlation with scored degree of mucosal injury (r=0.396;P<0.01). Among other possible laboratory markers of the disease activity, only C-reactive protein concentration demonstrated significant correlation. Enhanced production of TGF-β1can be related to inflammation activity. Measurement of plasma TGF-β1may be considered as a biomarker of the disease activity. 相似文献
7.
Carlos Gregorio Silvina Eduardo Luis C. Rodrigues María A. Regueira Ramn Fraga Ricardo Riveiros Miguel Maestro Antonio Mourio 《The Journal of steroid biochemistry and molecular biology》2007,103(3-5):227
Hapten derivatives of 25-hydroxyvitamin D3 and 1α,25-dihydroxyvitamin D3 were synthesized using the Wittig–Horner approach. Both haptens bearing a carboxylic group at the side chain that can be linked to a protein for raising antibodies of potential utility for the determination of 25-hydroxyvitamin D3, 1α,25-dihydroxyvitamin D3 and 1α-hydroxylated vitamin D3 analogues. 相似文献
8.
Three columns were differentiated with feeding mixture of H2S and NH3 (MFC), feeding NH3 followed by H2S (NFC), and feeding H2S followed by NH3 (SFC). Removal performance, biodegradation capacity and microbial community structures in the three columns were compared. The results show that NFC has a shorter acclimation period for the removal of NH3 gas and nitrification than MFC. Under the high loading of H2S and NH3 at 164 and 82 g m−3 h−1, respectively, NFC exhibited high removal efficiency of NH3 (>95%) while the removal efficiencies were obtained at 63 and 75% in MFC and SFC, respectively. The removal of NH3 gas in NFC was significantly attributed to nitrification (over 50%), while adsorption and chemical reaction contributed to the removal of NH3 in MFC and SFC. The different biodegradation capacities of NH3 could be due to the dissimilarity in the microbial population presented in each column. 相似文献
9.
Michal Hofer Milan Pospí?il Ladislav Du?ek Zuzana Hoferová Denisa Kom?rková 《Purinergic signalling》2015,11(1):79-85
Adenosine A3 receptor knockout (A3AR KO) mice and their wild-type (WT) counterparts were compared from the point of view of their abilities to survive exposures to lethal doses of γ-radiation belonging to the range of radiation doses inducing the bone marrow acute radiation syndrome. Parameters of cumulative 30-day survival (experiment using a midlethal radiation dose) or cumulative 11-day survival (experiment using an absolutely lethal radiation dose), and of mean survival time were evaluated. The values of A3AR KO mice always reflected their higher survival in comparison with WT ones, the P values being above the limit for statistical significance after the midlethal radiation dose and standing for statistical significance after the absolutely lethal radiation dose. This finding was considered surprising, taking into account the previously obtained findings on defects in numbers and functional properties of peripheral blood cells in A3AR KO mice. Therefore, previous hematological analyses of A3AR KO mice were supplemented in the present studies with determination of serum levels of the granulocyte colony-stimulating factor, erythropoietin, and thrombopoietin. Though distinct differences in these parameters were observed between A3AR KO and WT mice, none of them could explain the relatively high postirradiation survival of A3AR KO mice. Further studies on these mice comprising also those on other than hemopoietic tissues and organs can help to clarify their relative radioresistance. 相似文献
10.
David Fushman 《Journal of molecular biology》2010,395(4):803-472
Posttranslational modification of proteins by covalent attachment of a small protein ubiquitin (Ub) or a polymeric chain of Ub molecules (called polyubiquitin) is involved in controlling a vast variety of processes in eukaryotic cells. The question of how different polyubiquitin signals are recognized is central to understanding the specificity of various types of polyubiquitination. In polyubiquitin, monomers are linked to each other via an isopeptide bond between the C-terminal glycine of one Ub and a lysine of the other. The functional outcome of polyubiquitination depends on the particular lysine involved in chain formation and appears to rely on linkage-dependent conformation of polyubiquitin. Thus, K48-linked chains, a universal signal for proteasomal degradation, under physiological conditions adopt a closed conformation where functionally important residues L8, I44, and V70 are sequestered at the interface between two adjacent Ub monomers. By contrast, K63-linked chains, which act as a nonproteolytic regulatory signal, adopt an extended conformation that lacks hydrophobic interubiquitin contact. Little is known about the functional roles of the so-called “noncanonical” chains (linked via K6, K11, K27, K29, or K33, or linked head-to-tail), and no structural information on these chains is available, except for information on the crystal structure of the head-to-tail-linked diubiquitin (Ub2). In this study, we use molecular modeling to examine whether any of the noncanonical chains can adopt a closed conformation similar to that in K48-linked polyubiquitin. Our results show that the eight possible Ub2 chains can be divided into two groups: chains linked via K6, K11, K27, or K48 are predicted to form a closed conformation, whereas chains linked via K29, K33, or K63, or linked head-to-tail are unable to form such a contact due to steric occlusion. These predictions are validated by the known structures of K48-, K63-, and head-to-tail-linked chains. Our study also predicts structural models for Ub2 chains linked via K6, K11, or K27. The implications of these findings for linkage-selective recognition of noncanonical polyubiquitin signals by various receptors are discussed. 相似文献
11.
The metabolic pathway of primary carbon fixation was studied in a peculiar pennate marine diatom, Haslea ostrearia (Bory) Simonsen, which synthesizes and accumulates a blue pigment known as “marennine”. Cells were cultured in a semi-continuous
mode under saturating [350 μmol(photon) m−2 s−1] or non-saturating [25 μmol(photon) m−2 s−1] irradiance producing “blue” (BC) and “green” (GC) cells, characterized by high and low marennine accumulation, respectively.
Growth, pigment contents (chlorophyll a and marennine), 14C accumulation in the metabolites, and the carbonic anhydrase (CA) activity of the cells were determined during the exponential
growth phase. Growth rate and marennine content were closely linked to irradiance during growth: higher irradiance increased
both growth rate and marennine content. On the other hand, the Chl a concentration was lower under saturating irradiance. The distribution between the Calvin-Benson (C3) and β-carboxylation (C4) pathways was very different depending on the irradiance during growth. Metabolites of the C3 cycle contained about 70 % of the total fixed radioactivity after 60 s of incorporation into cells cultured under the non-saturating
irradiance (GC), but only 47 % under saturating irradiance (BC). At the same time, carbon fixation by β-carboxylation was
24 % in GC versus about 41 % in BC, becoming equal to that in the C3 fixation pathway in the latter. Internal CA activity remained constant, but the periplasmic CA activity was higher under
low than high irradiance. 相似文献
12.
Shuhong Yu Jie Xiao Hong Xu Yushiang Lin Jhysheng Chang Yanbin Li Dezhen Gao Shuai Pang Zhiyuan Xu Tianhong Miao 《Asia-Pacific Journal of Blood Types and Genes》2017,1(2):71-74
Rhnull syndrome is a very rare disease. Patients with this syndrome present with negative serological Rh typing of E, e, C, c, and D antigens. Only one study has previously discussed Rhnull syndrome in Chinese individuals. We experienced two patients with Rhnull syndrome in China, Rh genotypes being CcDEe in the first patient and CCDee in the second patient. The first patient was a pregnant woman (gravida 2, para 1) with a negative red blood cell (RBC) antibody screen test. The second patient was a middle-aged man, transfused with ccdee, ccdEe, and ccdee RBC products, the pre-transfusion specimen was negative and post-transfusion specimen was anti-c,e, respectively. The hemoglobin level continued to increase in the second patient after being transfused with ccdEe RBC products. In the first patient, the result of the antibody screen test was still negative after artificial abortion. In patients with Rhnull syndrome, RBC products that have the same Rh genotype as the patient can be safely transfused. 相似文献
13.
Soil Temperature, Not Aboveground Plant Productivity, Best Predicts Intra-Annual Variations of Soil Respiration in Central Iowa Grasslands 总被引:2,自引:0,他引:2
Soil respiration (RSOIL) is the second largest carbon flux between terrestrial systems and the atmosphere, with a magnitude 10 times greater than
anthropogenic carbon dioxide production. Therefore, it is important that we understand, and be able to predict, how RSOIL responds to climate change. Although a positive, significant temperature effect on RSOIL has long been recognized, recent studies emphasize the overriding importance of current photosynthesis in controlling RSOIL. We tested the hypothesis that model inclusion of intra-annual variations in aboveground net primary productivity (ANPP)
significantly improves RSOIL estimates over predictions based on soil temperature alone. We also evaluated the possibility that canopy production is less
directly linked to RSOIL, by testing the hypothesis that intersite differences in RSOIL correlate more strongly with root biomass than with ANPP. We tested these hypotheses by measuring RSOIL, ANPP, and root biomass at four Iowa grasslands that differed in aboveground growth phenology and productivity. Among all
sites, intra-annual variations in RSOIL were most strongly related to soil temperature (R
2 = 0.89), not ANPP (R
2 = 0.53). All sites responded identically to changes in soil temperature (site-by-temperature P = 0.53), but inconsistently to variation in aboveground dynamics (site-by-canopy P < 0.0001). Incorporating canopy dynamics into temperature-based predictive models improved model R
2 by a maximum of 0.01. Among-site differences in RSOIL were related to root biomass (P < 0.001) but not ANPP (P = 0.34). We found no useful linkage between canopy characteristics and intra-annual or site-specific RSOIL predictions, perhaps because shoot and root dynamics were not consistently linked through time or among sites. 相似文献
14.
Early molecular events in the hippocampus of rats with streptozotocin-induced diabetes 总被引:1,自引:1,他引:0
In our study, we tried to find whether changes in expressions of inducible nitric oxide synthase (iNOS), corticosteroid (gluco-and
mineralocorticoid) receptors (GRs and MRs, respectively), and bcl2 protein within the early stages of streptozotocin (STZ)-induced diabetes in Wistar rats can be involved in hippocampal dysfunction.
Expressions of iNOS and bcl2 were studied using indirect immunofluorescence techniques, while GR and MR expressions were estimated using in situ mRNA hybridization. The concentrations of insulin, ACTH, and corticosterone in the blood serum were measured using ELISA
kits. It was found that expression of iNOS in the CA2 and CA3 hippocampal areas increased significantly at day 3 after STZ injection, and corticosterone and ACTH levels in the serum increased
at day 14. The iNOS expression was downregulated at day 14 of the development of diabetes. These changes were accompanied
by significantly increased expression of GRs in the hippocampus. Neither bcl2 nor MR expression increased in the CA2 and CA3 hippocampal areas within the examined period of the development of diabetes. Thus, we first obtained proof of noticeable
early molecular events in the rat hippocampus related to experimental diabetes. These events may be linked with diabetes-associated
cognitive decline observed in patients suffering from diabetes.
Neirofiziologiya/Neurophysiology, Vol. 39, No. 6, pp. 498–502, November–December, 2007. 相似文献
15.
SBA-15 and SBA-3 mesoporous silicas are synthesised by P123 and CTAB surfactants via hydrothermal and liquid phase deposition procedures, respectively. An inorganic-organic hybrid mesoporous material is then synthesised by functionalization of SBA-15 with aminopropyl functional groups via grafting method. After characterization, effect of immobilizing support and functional groups on intercalation of phosphomolybdic acid (H3PMo12O40) is taken into consideration. The immobilization pattern is discussed and supported H3PMo12O40 catalysts are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), EDX, inductively coupled plasma (ICP), FT-IR, and UV-vis analysis. The newly synthesised hybrid catalysts are investigated for epoxidation of cyclooctene in presence of hydrogen peroxide as oxidant. The reaction mechanism is discussed. Furthermore, effects of different immobilizing supports and functionalization on catalyst activity, stability, and reusability are taken into consideration. Similar catalytic reactions are carried out with pristine supports and neat H3PMo12O40 (homogeneous). Results reveal that the mesostructured phosphomolybdic acid based catalysts are shown to be efficient and selective heterogeneous catalysts for oxidation of alkenes. 相似文献
16.
Esma R. Isenovic Maxence Fretaud Emina Sudar Bozidarka Zaric Pierre Marche 《Cell biology international》2009,33(3):386-392
Insulin (INS) via INS receptor acts as a mitogen in vascular smooth muscle cells (VSMCs) through stimulation of multiple signaling mechanisms, including p42/44 mitogen-activated protein kinase (ERK1/2) and phosphatidyl inositol-3 kinase (PI3K). In addition, cytosolic phospholipase 2 (cPLA2) is linked to VSMCs proliferation. However, the upstream mechanisms responsible for activation of cPLA2 are not well defined. Therefore, this investigation used primary cultured rat VSMCs to examine the role of PI3K and ERK1/2 in the INS-dependent phosphorylation of cPLA2 and proliferation induced by INS. Exposure of VSMCs to INS (100 nM) for 10 min increased the phosphorylation of cPLA2 by 1.5-fold (p < 0.01), which was blocked by the cPLA2 inhibitor MAFP (10 μM; 15 min). Similarly, the PI3K inhibitor LY294002 (10 μM; 15 min) and ERK1/2 inhibitor PD98059 (20 μM; 15 min) abolished the INS-mediated increase in cPLA2 phosphorylation by 59% (p < 0.001), and by 75% (p < 0.001), respectively. Further, inhibition of cPLA2 with cPLA2 inhibitor MAFP abolished the INS-stimulated ERK1/2 phosphorylation by 65% (p < 0.01). Incubation of rat VSMCs with INS resulted in an increase of VSMCs proliferation by 85% (p < 0.001). The effect of INS on VSMCs proliferation was significantly (p < 0.01) reduced by pretreatment with MAFP. Thus, we hypothesized that INS stimulates VSMCs proliferation via a mechanism involving the PI3K-dependent activation of cPLA2 and release of arachidonic acid (AA), which activates ERK1/2 and further amplifies cPLA2 activity. 相似文献
17.
高浓度二氧化碳和臭氧对蒙古栎叶片活性氧代谢的影响 总被引:3,自引:0,他引:3
利用开顶箱熏蒸法,研究了高浓度O3(≈80 nmol·mol-1)和高浓度CO2(≈700 μmol·mol-1)及其复合处理对蒙古栎叶片活性氧代谢的影响.结果表明:高浓度O3显著增加了蒙古栎叶片超氧阴离子(O2•)产生速率、过氧化氢(H2O2)和丙二醛(MDA)含量和电解质外渗率(P<0.05),显著降低了超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性和抗坏血酸(AsA)含量(P<0.05).高浓度CO2对蒙古栎叶片活性氧代谢影响不显著.高浓度O3和CO2复合处理的叶片O2•产生速率、H2O2和MDA含量和电解质外渗率上升不明显,说明高浓度CO2缓解了高浓度O3对蒙古栎叶片的氧化胁迫.复合处理的叶片SOD、CAT、APX活性以及AsA和总酚含量显著高于O3处理的叶片(P<0.05),说明高浓度CO2缓解了高浓度O3对叶片抗氧化系统的消极影响. 相似文献
18.
Eicosapentaenoic acid (EPA) metabolism into 3 series cyclooxygenase and 5 series lipoxygenase products was assessed in human and rabbit anterior uvea. Both tissues synthesized 3 series cyclooxygenase products such as delta17 6-keto-PGF1 (PGI3 metabolite), PGF3, PGE3, PGD3 and TxB3 (a stable product of TxA3) and lipoxygenase products 12-hydroxyeicosapentaenoic acid (HEPE), 5-HEPE and 5,12-diHEPE from 14C-EPA. EPA-derived cyclooxygenase product synthesis was considerably greater than the formation of lipoxygenase products from EPA in both tissues. 相似文献
19.
Summary The nature of the photosynthetic pathways of Cyperaceae found in Japan were investigated on the basis of Kranz anatomy, the CO2 compensation concentration and previously reported data. Among 301 species (96% of all cyperaceous species recorded in the region), 58 species were classified as being C4 plants. These C4 species were scattered among the tribes Fimbristylideae, Lipocarpheae, Cypereae and Rhynchosporeae in the subfamily Cyperoideae. The genera Cyperus, Eleocharis and Rhynchospora included, in Japan, both C3 and C4 species within a single genus. Using these data, an analysis was made of the ecological characteristics and geographical distribution of the C3 and C4 species in Japan. Although cyperaceous species grow in markedly different environments, the majority were found in wet and aquatic areas (61%) or shaded areas, such as forest floors (20%). Most of the C3 species were also hygrophytes (58%) and forest-living species (25%), and C3 species growing in mesic and dry areas were relatively rare. The C4 species inhabited wet and aquatic (75%), mesic (13%) and dry areas (6%) and showed marked ecological characteristics with respect to soil-moisture conditions, unlike other C4 plants, although they were absent from shaded habitats. In order to determine the climatic factors that influence the relative floristic abundance of C3 and C4 members of the Cyperaceae in Japan, the ratios of number of C4 species to the total number of members of Cyperaceae (C4 percentage) in 16 representative locales were examined in terms of various climatic variables. There were strong positive correlations between the C4 percentage and temperature. Among the C3 groups of three subfamilies, there were different distributional trends for various temperature regimes. The C3 subfamily Caricoideae increased its relative contribution to the cyperaceous flora with a decrease in mean annual temperature, while the C3 subfamily Sclerioideae exhibited the opposite pattern. The C3 group of the subfamily Cyperoideae did not show any marked change in pattern along temperature gradients, unlike the two other C3 subfamilies, and seemed to be heterogeneous in terms of its response to temperature. The relationships between the C4 biochemical subtypes and ecological characteristics are also discussed. 相似文献
20.
Overactivation of ionotropic glutamate receptors induces a Ca2+ overload into the cytoplasm that leads neurons to excitotoxic death, a process that has been linked to several neurodegenerative disorders. While the role of mitochondria and its involvement in excitotoxicity have been widely studied, the contribution of endoplasmic reticulum (ER), another crucial intracellular store in maintaining Ca2+ homeostasis, is not fully understood. In this study, we analyzed the contribution of ER-Ca2+ release through ryanodine (RyR) and IP3 (IP3R) receptors to a neuronal in vitro model of excitotoxicity. NMDA induced a dose-dependent neuronal death, which was significantly decreased by ER-Ca2+ release inhibitors in cortical neurons as well as in organotypic slices. Furthermore, ryanodine and 2APB, RyR and IP3R inhibitors respectively, attenuated NMDA-triggered intracellular Ca2+ increase and oxidative stress, whereas 2APB reduced mitochondrial membrane depolarization and caspase-3 cleavage. Consistent with ER-Ca2+ homeostasis disruption, we observed that NMDA-induced ER stress, characterized here by eIF2α phosphorylation and over-expression of GRP chaperones which were regulated by ER-Ca2+ release inhibitors. These results demonstrate that Ca2+ release from ER contributes to neuronal death by both promoting mitochondrial dysfunction and inducing specific stress and apoptosis pathways during excitotoxicity. 相似文献