共查询到20条相似文献,搜索用时 718 毫秒
1.
Yurong Zhang Zuyi Yuan Heng Ge Yanping Ren 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2010,180(1):117-124
To examine the effects of chronic ouabain treatment on blood pressure (BP), sodium excretion, and renal dopamine D1 receptor level, male Sprague-Dawley (SD) rats were treated with ouabain (27.8 μg kg−1 d−1) intraperitoneally for 5 weeks, and systolic blood pressure (SBP) were recorded weekly. After 5 weeks, sodium excretion and
dopamine D1 receptor agonist fenoldopam-mediated natriuresis were measured, and the expression and phosphorylation levels of the renal
cortical dopamine D1 receptor were confirmed by Western blot analysis. The effects of ouabain on fenoldopam-mediated inhibition of Na+-K+-ATPase activity were determined by colorimetric assays in human proximal tubular epithelial cells (HK-2 cells). After 5 weeks,
the SBP in ouabain group was significantly higher than that in the control group (P < 0.01), but the sodium excretion and renal cortical D1 receptor expression levels were reduced, and D1 receptor phosphorylation levels were increased after ouabain treatment. Intravenous administration of fenoldopam caused an
increased sodium excretion in control rats, but failed to induce natriuresis in ouabain-treated rats. In addition, fenoldopam
induced a dose–respone (10−9 to 10−6 M) inhibition of Na+-K+-ATPase activity in HK-2 cells,but these effects were significantly diminished in HK-2 cells pretreated with nanomolar concentration
of ouabain for 5 days (P < 0.01). We propose that the ouabain-induced reduction of the renal dopamine D1 receptor function serves as a mechanism responsible for sodium retention, and this contributes to the hypertension induced
by chronic ouabain treatment. 相似文献
2.
Soltani F Mosaffa F Iranshahi M Karimi G Malekaneh M Haghighi F Behravan J 《Cell biology and toxicology》2009,25(3):291-296
The protective properties of a prenylated coumarin, umbelliprenin (UMB), on the human lymphocytes DNA lesions were tested.
Lymphocytes were isolated from blood samples taken from healthy volunteers. DNA breaks and resistance to H2O2-induced damage were measured using a single-cell microgel electrophoresis technique under alkaline conditions (comet assay).
Human lymphocytes were incubated in UMB (10, 25, 50, 100, 200, and 400 μM) alone or a combination of different concentrations
of UMB (10, 25, 50, 100, 200, and 400 μM) and 25 μM H2O2. Untreated cells, ascorbic acid (AA; 25, 50, 100, 200, and 400 μM) and H2O2 (25 μM) were considered as negative control, positive control, and the standard antioxidant agent for our study, respectively.
Single cells were analyzed with “TriTek Cometscore version 1.5” software. The DNA damage was expressed as percent tail DNA.
UMB exhibited a concentration-dependent increase in protection activity against DNA damage induced by 25 μM H2O2 (from 67.28% to 39.17%). The antigenotoxic activity of AA, in the range 0–50 μM, was greater than that of UMB. However, no
significant difference (p > 0.05) in the protective activity was found between UMB and AA at concentrations of approximately higher than 50 μM. 相似文献
3.
Wei XJ Wu J Ni YD Lu LZ Zhao RQ 《In vitro cellular & developmental biology. Animal》2011,47(10):735-741
Previous studies have shown that the in ovo injection of equol can markedly improve the water-holding capacity of muscles
of broilers chickens at 7 wk of age through promotion of the antioxidant status. We aimed to investigate directly the antioxidant
effects of equol on muscle cells in broilers. Muscle cells were separated from leg muscle of embryos on the 11th day of incubation
and treated with equol and H2O2, either alone or together. Cells were pretreated with medium containing 1, 10, or 100 μM equol for 1 h prior to the addition
of 1 mM H2O2 for a further 1 h. Photomicrographs of cells were obtained. Cell viability, malondialdehyde (MDA) content, and L-lactate
dehydrogenase (LDH) activity in the cell supernatant, as well as intracellular total superoxide dismutase (T-SOD) and glutathione
peroxidase (GSH-Px) activities were determined. Treatment with 1 mM H2O2 caused serious damage to cells, indicated by comets with no clear head region but a very apparent tail of DNA fragments.
Pretreatment with low (1 μM) but not high concentrations of equol (10 μM) inhibited cell damage, while 100 μM equol caused
more serious damage than H2O2 alone. Pretreatment with 1 μM equol had no effect on cell viability, while pretreatment with 10 and 100 μM equol significantly
decreased cell viability in a dose-dependent manner. Compared with H2O2 alone, pretreatment with low-dosage equol markedly decreased LDH activity and MDA production in the supernatant, significantly
increased intracellular T-SOD activity (P < 0.05) and tended to increase intracellular GSH-Px activity (0.05 < P < 0.1). Pretreatment with high-dosage equol (10 and 100 μM) significantly enhanced LDH activity, but had no effect on MDA
content, T-SOD or GSH-Px activity induced by H2O2, except for an obvious increase in GSH-Px activity caused by 10 μM equol. These results indicate that equol at low dosage
can prevent skeletal muscle cell damage induced by H2O2, while pretreatment with high-dosage equol shows a synergistic effect with H2O2 in inducing cell damage. 相似文献
4.
Icilin is recognized as a chemical agonist of nociceptors and can activate TRPM8 channels. However, whether this agent has
any effects on immune cells remains unknown. In this study, the effects of icilin on ion currents were investigated in RAW
264.7 murine macrophage-like cells. Icilin (1–100 μM) increased the amplitude of nonselective (NS) cation current (I
NS) in a concentration-dependent manner with an EC50 value of 8.6 μM. LaCl3 (100 μM) or capsazepine (30 μM) reversed icilin-induced I
NS; however, neither apamin (200 nM) nor iberiotoxin (200 nM) had any effects on it. In cell-attached configuration, when the
electrode was filled with icilin (30 μM), a unique population of NS cation channels were activated with single-channel conductance
of 158 pS. With the use of a long-lasting ramp pulse protocol, increasing icilin concentration produced a left shift in the
activation curve of NS channels, with no change in the slope factor of the curve. The probability of channel opening enhanced
by icilin was increased by either elevated extracellular Ca2+ or application of ionomycin (10 μM), while it was reduced by BAPTA-AM (10 μM). Icilin-stimulated activity is associated with
an increase in mean open time and a reduction in mean closed time. Under current-clamp conditions, icilin caused membrane
depolarization. Therefore, icilin interacts with the TRPM8-like channel to increase I
NS and depolarizes the membrane in these cells. 相似文献
5.
Maria-Eleni Androutsou Mahmoud Saifeddine Morley D. Hollenberg John Matsoukas George Agelis 《Amino acids》2010,38(4):985-990
In the present study, we report the synthesis and biological evaluation of a series of new non-peptide PAR1 mimetic receptor antagonists, based on conformational analysis of the S42FLLR46 tethered ligand (TL) sequence of PAR1. These compounds incorporate the key pharmacophore groups in the TL sequence, guanidyl, amino and phenyl, which are essential
for triggering receptor activity. Compounds 5 and 15 (50–100 μM) inhibited both TFLLR-amide (10 μM) and thrombin-mediated (0.5 and 1 U/ml; 5 and 10 μM) calcium signaling in a
cultured human HEK cell assay. 相似文献
6.
Bone marrow-derived mesenchymal stem cells (BMSCs) are of particular interest in the field of tissue engineering because of
their potential to differentiate into osteoblasts, chondrocytes, and neuronal cells. In order to promote the differentiation
of BMSCs into specific cell types, appropriate scaffold biomaterials and bioactive molecules that can support the differentiation
of BMSCs into specific cell types are needed. We hypothesized that β-mercaptoethanol (BME), which has been reported to induce
the differentiation of BMSCs into neural-like cells, promotes BMSCs to differentiate into neural-like cells when BME is added
to polymeric scaffolds containing the BMSCs. We fabricated biocompatible film shaped scaffolds composed of poly(lacti-co-glycolic)
acid (PLGA) and various concentrations of BME to confirm that BME-promoted differentiation of BMSCs is concentration-dependent.
Cell proliferation increased as the BME concentration in the films increased at the early stage, and the proliferation rate
remained similar on the PLGA films for 3 weeks following the BMSC seeding. The expression of neuronal markers in differentiated
BMSCs was assessed by RT-PCR. At 2- and 3-week time-points, mRNA expression of neurofilament and neuron specific enolase was
significantly increased in PLGA/BME films containing 400 μM BME compared to PLGA films. Thus, we have identified BMSC-seeded
PLGA/BME films with 200 μM and 400 μM BME as potentially useful candidates for neural tissue engineering applications by promoting
BMSC proliferation and differentiation towards neural-like cells. 相似文献
7.
Wormser C Pore SA Elperin AB Silverman LN Light DB 《The Journal of membrane biology》2011,242(2):75-87
This study examined the role of a P2 receptor and arachidonic acid (AA) in regulatory volume decrease (RVD) by American alligator
red blood cells (RBCs). Osmotic fragility was determined optically, mean cell volume was measured by electronic sizing, and
changes in intracellular Ca2+ concentration were visualized using fluorescence microscopy. Gadolinium (50 μM), hexokinase (2.5 U/ml), and suramin (100 μM)
increased osmotic fragility, blocked volume recovery after hypotonic shock, and prevented a rise in intracellular Ca2+ that normally occurs during cell swelling. The P2X antagonists PPADS (50 μM) and TNP-ATP (10 μM) also increased fragility
and inhibited volume recovery. In contrast, ATPγS (10 μM), α,β-methylene-ATP (50 μM) and Bz-ATP (50 μM) had the opposite effect,
whereas 2-methylthio-ATP (50 μM) and UTP (10 μM) had no effect. In addition, the phospholipase A2 (PLA2) inhibitors ONO-RS-082 (10 μM), chlorpromazine (10 μM), and isotetrandrine (10 μM) increased osmotic fragility and blocked
volume recovery, whereas AA (10 μM) and its nonhydrolyzable analog eicosatetraynoic acid (ETYA, 10 μM) had the reverse effect.
Further, AA (10 μM), but not ATPγS (10 μM), prevented the inhibitory effect of a low Ca2+-EGTA Ringer on RVD, whereas both AA (10 μM) and ATPγS (10 μM) caused cell shrinkage under isosmotic conditions. In conclusion,
our results are consistent with the presence of a P2-like receptor whose activation stimulated RVD. In addition, AA also was
important for volume recovery. 相似文献
8.
Selvatici R Previati M Marino S Marani L Falzarano S Lanzoni I Siniscalchi A 《Neurochemical research》2009,34(5):909-916
The features of neuronal damage induced by the mitochondrial toxin NaN3 were investigated in rat primary cortical neuron cultures. Cell viability (MTT colorimetric determination) and transmembrane
mitochondrial potential (J-C1 fluorescence) were concentration-dependently reduced 24 h after NaN3; neither nuclear fragmentation by DAPI, nor Annexin V positivity by flow cytometry were detected, ruling out the occurrence
of apoptosis. The loss in cell viability (to 54 ± 2%) observed 24 h after a 10-min treatment with 3 mM NaN3 was prevented by the NMDA glutamate receptor antagonist MK801 (1 μM), by the antioxidants trolox (100 μM) and acetyl-l-carnitine (1 mM) and by the nitric oxide synthase inhibitor, L-NAME (100 μM), but not by the guanylylcyclase inhibitor ODQ,
10 μM. The mitochondrial dysfunction induced by NaN3 provides a common platform for investigating the mechanisms of both ischemic and degenerative neuronal injury, useful for
screening potential protective agents against neuronal death.
Rita Selvatici and Maurizio Previati equally contributed to the work. 相似文献
9.
Caroline Wagner Jéssie H. Sudati Cristina W. Nogueira João B. T. Rocha 《Biometals》2010,23(6):1171-1177
The thioredoxin (Trx) system, involving redox active Trxs and thioredoxin reductases (TrxRs), sustain a number of important
Trx-dependent pathways. These redox active proteins support several processes crucial for cell function, cell proliferation,
antioxidant defense, and redox-regulated signaling cascades. Methylmercury (MeHg) is an important environmental toxicant that
has a high affinity for thiol groups and can cause oxidative stress. The Trx system is the major system responsible for maintaining
the redox state of cells and this function involves thiol reduction mediated by selenol groups in TrxRs. MeHg has a great
affinity to thiols and selenols, thus the potential toxic effects of MeHg on TrxR inhibition were determined in the current
study. A single administration of MeHg (1, 5, and 10 mg/Kg) caused a marked inhibition of kidney TrxR activity, while significant
inhibition was observed in the liver after exposure to 5 and 10 mg/Kg of MeHg. TrxR activity was determined 24 h after MeHg.
In the brain, MeHg did not inhibit TrxR activity. In vitro exposure to MeHg indicated that MeHg inhibits cerebral (IC50, 0.158 μM), hepatic (IC50, 0.071 μM), and renal TrxR activity (IC50, 0.078 μM). The results presented herein demonstrated for the first time that renal and hepatic TrxRs can serve as an in
vivo target for MeHg. This study suggests that MeHg can bind to selenocysteine residues present in the catalytic site of TrxR,
in turn causing enzyme inhibition that can compromise the redox state of cells. 相似文献
10.
Hsu-Feng Lu Jai-Sing Yang Kuang-Chi Lai Shu-Chun Hsu Shu-Ching Hsueh Yuan-Liang Chen Jo-Hua Chiang Chi-Cheng Lu Chyi Lo Mei-Due Yang Jing-Gung Chung 《Neurochemical research》2009,34(8):1491-1497
Curcumin is reported to be a potent inhibitor of the initiation and promotion of many cancer cells. We investigated to examine
whether or not curcumin induce DNA damage in mouse–rat hybrid retina ganglion cell line N18 cells. The Comet assay showed
that incubation of N18 cells with 10, 25 and 30 μM of curcumin led to a longer DNA migration smear (Comet tail). The DNA gel
electrophoresis showed that 20 μM of curcumin for 24 and 48 h treatment induced DNA damage and fragments in N18 cells. The
real time PCR analysis showed that 20 μM of curcumin for 48 h treatment decreased ATM, ATR, BRCA1, 14-3-3σ, DNA-PK and MGMT
mRNA, and ATM and MGMT mRNA expression were inhibited in a time-dependent manner. Our results indicate that curcumin caused
DNA damage and inhibited DNA repair genes which may be the factors for curcumin-inhibited cell growth.
H.-F. Lu and J.-S. Yang are contributed equally to this study. 相似文献
11.
The metabotropic GABAB and adenosine A1 receptors mediate presynaptic inhibition through regulation of voltage-dependent Ca2+ channels, whereas K+ channel regulation is believed to have no role at the CA3-CA1 synapse. We show here that the inhibitory effect of baclofen
(20 μM) and adenosine (300 μM) on field EPSPs are differentially sensitive to Cs+ (3.5 mM) and Ba2+ (200 μM), but not 4-aminopyridine (100 μM). Barium had no effect on paired-pulse facilitation (PPF) in itself, but gave significant
reduction (14 ± 5%) when applied in the presence of baclofen, but not adenosine, suggesting that the effect is presynaptic
and selective on the GABAB receptor-mediated response. The effect of Ba2+ on PPF was not mimicked by tertiapin (30 nM), indicating that the underlying mechanism does not involve GIRK channels. Barium
did not affect PPF in slices from young rats (P7–P8), suggesting developmental regulation. The above effects of Ba2+ on adult tissue were reproduced when measuring evoked whole-cell EPSCs from CA1 pyramidal neurons: PPF was reduced by 22 ± 3%
in the presence of baclofen and unaltered in adenosine. In contrast, Ba2+ caused no significant change in frequency or amplitude of miniature EPSCs. The Ba2+-induced reduction of PPF was antagonized by LY341495, suggesting metabotropic glutamate receptor involvement. We propose
that these novel effects of Ba2+ and Cs+ are exerted through blockade of inwardly rectifying K+ channels in glial cells, which are functionally interacting with the GABAB receptor-dependent glutamate release that generates heterosynaptic depression. 相似文献
12.
Effects of Cannabinoids on Caffeine Contractures in Slow and Fast Skeletal Muscle Fibers of the Frog
Miguel Huerta Mónica Ortiz-Mesina Xóchitl Trujillo Enrique Sánchez-Pastor Clemente Vásquez Elena Castro Raymundo Velasco Rocío Montoya-Pérez Carlos Onetti 《The Journal of membrane biology》2009,229(2):91-99
The effect of cannabinoids on caffeine contractures was investigated in slow and fast skeletal muscle fibers using isometric
tension recording. In slow muscle fibers, WIN 55,212-2 (10 and 5 μM) caused a decrease in tension. These doses reduced maximum
tension to 67.43 ± 8.07% (P = 0.02, n = 5) and 79.4 ± 14.11% (P = 0.007, n = 5) compared to control, respectively. Tension-time integral was reduced to 58.37 ± 7.17% and 75.10 ± 3.60% (P = 0.002, n = 5), respectively. Using the CB1 cannabinoid receptor agonist ACPA (1 μM) reduced the maximum tension of caffeine contractures by 68.70 ± 11.63% (P = 0.01, n = 5); tension-time integral was reduced by 66.82 ± 6.89% (P = 0.02, n = 5) compared to controls. When the CB1 receptor antagonist AM281 was coapplied with ACPA, it reversed the effect of ACPA on caffeine-evoked tension. In slow and
fast muscle fibers incubated with the pertussis toxin, ACPA had no effect on tension evoked by caffeine. In fast muscle fibers,
ACPA (1 μM) also decreased tension; the maximum tension was reduced by 56.48 ± 3.4% (P = 0.001, n = 4), and tension-time integral was reduced by 57.81 ± 2.6% (P = 0.006, n = 4). This ACPA effect was not statistically significant with respect to the reduction in tension in slow muscle fibers.
Moreover, we detected the presence of mRNA for the cannabinoid CB1 receptor on fast and slow skeletal muscle fibers, which was significantly higher in fast compared to slow muscle fiber expression.
In conclusion, our results suggest that in the slow and fast muscle fibers of the frog cannabinoids diminish caffeine-evoked
tension through a receptor-mediated mechanism. 相似文献
13.
Pumpkin ash (Fraxinus profunda (Bush) Bush) is at risk for extirpation by an exotic insect, the emerald ash borer (EAB). Pumpkin ash is limited to wetland
areas of the Eastern United States, and has been listed as an endangered species because of EAB activity. Pumpkin ash provides
many benefits to the ecosystem, and its wood is used in the manufacturing industry. In vitro regeneration provides an integral
tool for the mass propagation and genetic transformation of pumpkin ash to combat EAB. Therefore, a plant regeneration protocol
was developed for pumpkin ash. Aseptically extracted hypocotyls formed adventitious shoots following 4 weeks on Murashige
and Skoog (MS) medium supplemented with 0–22.2 μM 6-benzyladenine (BA) and 0–6.8 μM thidiazuron (TDZ) then transferred for
an additional 4 weeks on MS medium with Gamborg B5 vitamins plus 0.2 g L−1 glycine (B5G) containing 6.7 μM BA, 1 μM indole-3-butryic acid (IBA), and 0.29 μM gibberellic acid (GA3). As adventitious shoots developed, these were transferred to a MSB5G medium with 13.3 μM BA, 1 μM IBA, and 0.29 μM GA3 for shoot elongation. Elongated shoots were successfully micropropagated using MSB5 medium with 10 μM BA and 10 μM TDZ. Adventitious
root formation was as high as 94% using woody plant medium supplemented with 4.9 μM IBA with shoots cultured for 10 days in
the dark followed by culture under a 16-h photoperiod. Acclimatization to the greenhouse was successful and normal plant growth
was observed. This protocol will provide a means for genetic transformation for EAB resistance and mass propagation for conservation. 相似文献
14.
l-Arginine stimulates proliferation and prevents endotoxin-induced death of intestinal cells 总被引:1,自引:0,他引:1
Bie Tan Yulong Yin Xiangfeng Kong Peng Li Xilong Li Haijun Gao Xinguo Li Ruilin Huang Guoyao Wu 《Amino acids》2010,38(4):1227-1235
This study tested the hypothesis that l-arginine (Arg) may stimulate cell proliferation and prevent lipopolysaccharide (LPS)-induced death of intestinal cells. Intestinal
porcine epithelial cells (IPEC-1) were cultured for 4 days in Arg-free Dulbecco’s modified Eagle’s-F12 Ham medium (DMEM-F12)
containing 10, 100 or 350 μM Arg and 0 or 20 ng/ml LPS. Cell numbers, protein concentrations, protein synthesis and degradation,
as well as mammalian target of rapamycin (mTOR) and Toll-like receptor 4 (TLR4) signaling pathways were determined. Without
LPS, IPEC-1 cells exhibited time- and Arg-dependent growth curves. LPS treatment increased cell death and reduced protein
concentrations in IPEC-1 cells. Addition of 100 and 350 μM Arg to culture medium dose-dependently attenuated LPS-induced cell
death and reduction of protein concentrations, in comparison with the basal medium containing 10 μM Arg. Furthermore, supplementation
of 100 and 350 μM Arg increased protein synthesis and reduced protein degradation in both control and LPS-treated IPEC-1 cells.
Consistent with the data on cell growth and protein turnover, addition of 100 or 350 μM Arg to culture medium increased relative
protein levels for phosphorylated mTOR and phosphorylated ribosomal protein S6 kinase-1, while reducing the relative levels
of TLR4 and phosphorylated levels of nuclear factor-κB in LPS-treated IPEC-1 cells. These results demonstrate a protective
effect of Arg against LPS-induced enterocyte damage through mechanisms involving mTOR and TLR4 signaling pathways, as well
as intracellular protein turnover. 相似文献
15.
The mechanisms of protective effect of N-methyl-D-aspartate (NMDA) receptor stimulation on apoptosis of neurons at their early
stage of development are poorly understood. In the present study, we investigated the effects of NMDA on staurosporine (St)-
and low-potassium (LP)-evoked apoptotic cell death in primary cerebellar granule cell (CGC) cultures at 7 days in vitro (DIV).
We found that NMDA (200 μM) attenuated the St (0.5 μM)- and LP (5 mM KCl)-induced neuronal cell death in 7 but not 12 DIV
CGC as confirmed by LDH release and MTT reduction assays. Moreover, NMDA attenuated St-and LP-evoked DNA fragmentation and
cytosolic apoptosis inducing factor (AIF) protein level but not caspase-3 activation induced by both pro-apoptotic factors.
Neuroprotective effects of NMDA on St-induced apoptosis in CGC were attenuated by inhibitors of ERK/MAPK-signaling, PD 98059
and U0126 but not by NMDA receptor antagonists, AP-5 (100 μM) and MK-801 (1 μM) or by inhibitors of PI3-K/Akt pathway (LY
294002 and wortmannin). In contrast to staurosporine model of apoptosis, AP-5 and MK-801 but not inhibitors of PI3-K/Akt and
MAPK/ERK1/2 prevented the NMDA-mediated neuroprotection in LP-induced apoptosis of CGC. In separate experiments, we observed
also the anti-apoptotic action of NMDA on St (0.5 μM)- and salsolinol (250 μM)-evoked cell death in human neuroblastoma SH-SY5Y
cells without its influence on caspase-3 activity, induced by these pro-apoptotic factors. These data indicate that neuroprotection
evoked by NMDA in CGC strongly depends on used pro-apoptotic agent and could engage NMDA channel function or be connected
with the activation of pro-survival MAPK/ERK1/2 pathway. It is also suggested that anti-apoptotic effects of NMDA is connected
with inhibition of fragmentation of DNA via caspase-3-independent mechanism. 相似文献
16.
To understand how plants from the Fabaceae family maintain zinc (Zn) homeostasis, we have characterized the kinetics of three
Zn transporting proteins from the ZIP family of divalent metal transporters in the model legume Medicago truncatula. Of six ZIP’s studied, MtZIP1, MtZIP5 and MtZIP6 were the only members from this family determined to transport Zn and were
further characterized. MtZIP1 has a low affinity for Zn with a Km of 1 μM as compared to MtZIP5 and MtZIP6 that have a higher affinity for Zn with Km of 0.4 μM and 0.3 μM, respectively. Zn transport by MtZIP1 was more sensitive to inhibition by copper (Cu) concentrations
than MtZIP5 and MtZIP6, because 3 μM Cu inhibited Zn transport by 80% in MtZIP1 while 5 μM Cu was required to achieve the
same inhibition of Zn transport in MtZIP5 and MtZIP6. Cadmium (Cd) had a greater effect on the ability of MtZIP1 to transport
Zn than MtZIP5 and MtZIP6, because at a concentration of 3 μM Cd, the Zn transport by MtZIP1 was inhibited 55% and the transport
of Zn by MtZIP5 and MtZIP6 was inhibited by 20–30%. However, only MtZIP6 transported Cd at higher rates than those observed
in the control plasmid pFL61, demonstrating a low affinity for Cd based on a Km of 57 μM. These results suggest that Medicago truncatula has both high and low affinity Zn transporters to maintain Zn homeostasis and that these transporters may function in different
compartments within the plant. 相似文献
17.
Direct effects on epithelial Na+ channels (ENaC) activity by lipids, e.g., arachidonic acid (AA), eicosatetraynoic acid (ETYA), linoleic acid (LA), stearic
acid (SA), hydroxyeicosatetraenoic acid (HETE), 11,12–epoxyeicosatrienoic acid (EET), (PGF2), and (PGE2), in cultured mouse
cortical collecting duct (M1) cells were clarified by using single-channel recordings in this study. In a cell-attached recording,
a bath application of 10 μM AA significantly reduced the ENaC open probability (NPo), whereas 10 μM ETYA or 5 μM LA only induced
a slight inhibition. The inside-out recording as a standard protocol was thereafter performed to examine effects of these
lipids on ENaC activity. Within 10 min after the formation of the inside-out configuration, the NPo of ENaC in cultured mouse
cortical collecting duct (M1) cells remained relatively constant. Application of ETYA or LA or SA exhibited a similar inhibition
on the channel NPo when applied to the extracellular side, suggesting that fatty acids could exert a nonspecific inhibition
on ENaC activity. 11,12-EET, a metabolite of AA via the cytochrome P450 epoxygenase pathway, significantly inhibited the ENaC
NPo, whereas 20-HETE, a metabolite of AA via the hydroxylase pathway, only caused a small inhibition of the ENaC NPo, to a
similar degree as that seen with ETYA and LA. However, both PGE2 and PGF2α significantly enhanced the ENaC NPo. These results
suggest that fatty acids exert a nonspecific effect on ENaC activity due to the interaction between the channel proximity
and the lipid. The opposite effects of 11,12-EET and prostaglandin (PG) implicate different mechanisms in regulation of ENaC
activity by activation of epoxygenase and cyclooxygenase. 相似文献
18.
Priyanka Srivastava Naresh Kasoju Utpal Bora Rakhi Chaturvedi 《Plant Cell, Tissue and Organ Culture》2009,99(1):1-7
Several secondary metabolites are present in Lantana camara L. as its leaves serve as reservoirs for various bioactive compounds. Callus cultures of L. camara were induced from leaf discs incubated on Murashige and Skoog medium supplemented with 5 μM 6-benzyladenine, 1 μM 2,4-dichlorophenoxyacetic
acid, and 1 μM α-naphthalene acetic acid (NAA). An aqueous extract (0.23%), obtained from these calli (50 g dry mass), had
an apparent cytotoxic effect on HeLa cells with an IC50 value of 1,500 μg/ml in 36 h. A dose-time dependent activity of the extract was established wherein higher dosage exhibited
increased activity; however, over time cell necrosis was observed. 相似文献
19.
Krystyna Konopka Barbara Dorocka-Bobkowska Senait Gebremedhin Nejat Düzgüneş 《Antonie van Leeuwenhoek》2010,97(4):413-417
Candida-associated denture stomatitis has a high rate of recurrence. Candida biofilms formed on denture acrylic are more resistant to antifungals than planktonic yeasts. Histatins, a family of basic
peptides secreted by the major salivary glands in humans, especially histatin 5, possess significant antifungal properties.
We examined antifungal activities of histatin 5 against planktonic or biofilm Candida albicans and Candida glabrata. Candida biofilms were developed on poly(methyl methacrylate) discs and treated with histatin 5 (0.01–100 μM) or fluconazole (1–200 μM).
The metabolic activity of the biofilms was measured by the XTT reduction assay. The fungicidal activity of histatin 5 against
planktonic Candida was tested by microdilution plate assay. Biofilm and planktonic C. albicans GDH18, UTR-14 and 6122/06 were highly susceptible to histatin 5, with 50% RMA (concentration of the agent causing 50% reduction
in the metabolic activity; biofilm) of 4.6 ± 2.2, 6.9 ± 3.7 and 1.7 ± 1.5 μM, and IC50 (planktonic cells) of 3.0 ± 0.5, 2.6 ± 0.1 and 4.8 ± 0.5, respectively. Biofilms of C. glabrata GDH1407 and 6115/06 were less susceptible to histatin 5, with 50% RMA of 31.2 ± 4.8 and 62.5 ± 0.7 μM, respectively. Planktonic
C. glabrata was insensitive to histatin 5 (IC50 > 100 μM). Biofilm-associated Candida was highly resistant to fluconazole in the range 1–200 μM; e.g. at 100 μM only ~20% inhibition was observed for C. albicans, and ~30% inhibition for C. glabrata. These results indicate that histatin 5 exhibits antifungal activity against biofilms of C. albicans and C. glabrata developed on denture acrylic. C. glabrata is significantly less sensitive to histatin 5 than C. albicans. 相似文献
20.
L. Ferraro S. Tanganelli L. Marani C. Bianchi L. Beani A. Siniscalchi 《Neurochemical research》1996,21(5):547-552
The effects of α-glycerylphosphorylcholine (α-GPC) on endogenous cortical GABA release were studied both in vivo and in vitro.
In freely moving rats, equipped with epidural cups, α-GPC (30–300 mg/kg i.p.) increased GABA release. This effect was potentiated
by atropine, both systematically administered (5 mg/kg i.p.) and locally applied (1.4 μM), but not by mecamylamine (4 mg/kg
i.p.). The α-GPC-induced increasein GABA release was abolished in rats pretreated with the α1 receptor antagonist prazosin (14 μg/kg i.p.). In cortical slices α-GPC (0.4 mM) increased the spontaneous GABA efflux. This effectwas abolished by tetrodotoxin (0.5 μM) and prazosin (1 μM), but not by atropine (0.15 μM) ormecamylamine (2.5μM). These results indicate that the facilitatory response by α-GPC on GABArelease does not depend on a direct activation of either muscarinic or nicotinic receptors, but suggest the involvement of the noradrenergic
system. 相似文献