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1.
《Cytokine》2011,53(3):210-214
To examine the roles of intracellular calcium in RANKL-induced bone marrow macrophages (BMMs) differentiation, the effects of intracellular calcium chelator BAPTA-AM on RANKL-induced BMMs differentiation, and the activation of its relating signal proteins (MAPKs, and the PI3K/Akt) were studied. BMMs were cultured with various concentrations of BAPTA-AM in the presence of M-CSF (25 ng/ml) and RANKL (25 ng/ml) for 7 days, osteoclastogenic ability, cytosolic free Ca2+ concentration, osteoclast survival and the expression of phosphorylated ERK1/2, SAPK/JNK, Akt and p38 MAPK were measured by TRAP staining, spectrofluorometer and Western blotting. BAPTA-AM inhibited osteoclastogenesis and osteoclast survival of BMMs by RANKL induction. In osteoclasts without the pretreatment of BAPTA-AM, the increased response of [Ca2+]i was observed within 15 min and the maximum was about 1.2 times that of control. This response was sustained for 30 min and returned to the control level at 1 h after RANKL-inducing, and the increased response of [Ca2+]i was completely abolished and sustained to at least 8 h by BAPTA-AM. Although immunoblotting data revealed that RANKL could activate the phosphorylation of ERK1/2, SAPK/JNK, Akt and p38 MAPK, the expression of ERK1/2, Akt and p38 MAPK phosphorylation was inhibited by BAPTA-AM dose-dependently. These results revealed that BAPTA-AM inhibit osteoclastogenic ability of BMMs via suppressing the increase of [Ca2+]i which lead to inhibit RANKL-induced the phosphorylation of ERK, Akt and p38 MAPK, but not JNK. This finding may be useful in the development of an osteoclastic inhibitor that targets intracellular signaling factors.  相似文献   

2.
AimsCisplatin (CP) promotes increased production of reactive oxygen species, which can activate p38 mitogen activated protein kinases (p38 MAPKs) leading to apoptosis and increased expression of proinflammatory mediators that intensify the cytotoxic effects of CP. We investigated the effect of the treatment with SB203580, a p38 MAPKs inhibitor, on oxidative stress, on the oxidation-associated signal, p38 MAPK and on apoptosis in CP-injected rats, starting after the beginning of the renal damage.Main methodsRats (n = 21) were injected with CP (5 mg/kg, i.p.) and 3 and 4 days after some of them (n = 8) were treated with SB203580 (0.5 mg/kg, i.p.). Controls (n = 6) received saline (i.p.). Two or five days after saline or CP injections, plasma creatinine, urinary volume, sodium and potassium fractional excretions, blood urea nitrogen and urinary lipid peroxidation were measured. The kidneys were removed for histological, apoptosis, immunohistochemical and Western blot studies.Key findingsCP caused abnormalities in kidney functions and structure associated with raised urinary peroxidation levels and higher number of apoptotic cells in the outer medulla. The immunostaining studies showed increased numbers of macrophages/monocytes and p-p38 MAPKs positive cells in the renal outer medulla. The increase of p-p38 MAPKs expression was confirmed by Western blot analysis. All of these alterations were attenuated by treatment with SB203580.SignificanceThese data suggest that the beneficial effect of SB203580 on CP-induced renal damage might be related, in part, to the blockade of p38 MAPK activation with reduction of the inflammatory process, oxidative stress and apoptotic cell death.  相似文献   

3.
《Journal of plant physiology》2014,171(3-4):276-284
The presence and activation of MAPK-like proteins in intertidal macroalgae is described in the current study. Two MAPK-like proteins of 40 and 42 kDa in size similar to p38 and JNK, of mammalian cells have been identified in six representative species of intertidal macroalgae from the Strait of Gibraltar (Southern Spain), namely in the chlorophytes Ulva rigida and Chaetomorpha aerea, the rhodophytes Corallina elongata and Jania rubens, and the phaeophytes Dictyota dichotoma and Dilophus spiralis. Phosphorylation of MAPK-like proteins was studied during semi-tidal cycles. Analysis of p38-like and JNK-like MAPKs in macroalgae protein extracts was carried out by using specific antibodies against the phosphorylated forms of both MAPKs. Protein blot analysis of samples collected from 2009 to 2011 in natural growing sites on days when either low or high tide occurred at midday, indicated that MAPK-like proteins in all species were highly phosphorylated in response to desiccation imposed by low tide or high irradiance. Phosphorylation of p38-like MAPK always preceded that of JNK-like MAPK. In addition, phosphorylation of MAPKs was fastest in rhodophytes, followed by chlorophytes and then finally phaeophytes. In the first group, phosphorylation was mostly dependent on desiccation, whereas both high irradiance and desiccation were responsible for p38-like and JNK-like phosphorylation in chlorophytes. In phaeophytes, high irradiance was mostly responsible for MAPK-like activation.  相似文献   

4.
Four types of resveratrol dimerized analogues were synthesized and evaluated in vitro on LPS-induced NO production in RAW 264.7 cells. The results showed that several compounds, especially those containing 1,2-diphenyl-2,3-dihydro-1H-indene core (type I), exhibited good inhibitory activities. Among 25 analogues, 12b showed a significant inhibitory activity (49% NO production at 10 μM, IC50 = 3.38 μM). Further study revealed that compound 12b could suppress LPS-induced iNOS expression, NO production, and IL-1β release in a concentration-dependently manner. The mechanism of action (MOA) involved for its anti-inflammatory responses was through signaling pathways of p38 MAPK and JNK1/2, but not ERK1/2.  相似文献   

5.
AimsPrevious studies suggested that p38 MAPK activation during sustained myocardial ischaemia and reperfusion was harmful. We hypothesize that attenuation of p38MAPK activity via dephosphorylation by the dual-specificity phosphatase MKP-1 should be protective against ischaemia/reperfusion injury. Since the glucocorticoid, dexamethasone, induces the expression of MKP-1, the aim of this study was to determine whether upregulation of this phosphatase by dexamethasone protects the heart against ischaemia/reperfusion injury.Main methodsMale Wistar rats were treated with dexamethasone (3 mg/kg/day ip) for 10 days, before removal of the hearts for Western blot (ip Dex ? P) or perfusion in the working mode (ip Dex + P). Hearts were subjected to 20 min global or 35 min regional ischaemia (36.5 °C) and 30 or 120 min reperfusion. In a separate series, dexamethasone (1 µM) was added to the perfusate for 10 min (Pre + Dex) before or after (Rep + Dex) ischaemia.Key findingsDexamethasone, administered intraperitoneally or added directly to the perfusate, significantly improved post-ischaemic functional recovery and reduced infarct size compared to untreated controls (p < 0.05). These were associated with enhanced up-regulation of MKP-1 protein expression (arbitrary units (mean ± SD): Untreated: 1; ip Dex ? P: 2.59 ± 0.22; ip Dex + P: 1.51 ± 0.22; Pre + Dex: 4.11 ± 0.73, Rep + 15′Dex: 1.51 ± 0.14; untreated vs. all groups, p < 0.05) and attenuation of p38 MAPK activation (p < 0.05) in all dexamethasone-treated groups, except for Rep + 10′Dex. ERK and PKB/Akt activation were unchanged.SignificanceDexamethasone-induced cardioprotection was associated with upregulation of the phosphatase MKP-1 and inactivation of pro-apoptotic p38 MAPK.  相似文献   

6.
A study was conducted to elucidate hormonal control of leptin receptor gene expression in primary cultures of porcine hepatocytes. Hepatocytes were isolated from swine and seeded into T-25 flasks. Cultures were established in medium containing fetal bovine serum for one day and switched to serum-free medium (William's E medium and 1 ng/mL insulin) for the remainder of the 3 d culture period. For the final 24 h, medium was supplemented with porcine growth hormone (GH, 100 or 500 ng/mL), insulin-like growth factor 1 (IGF-1, 50 to 250 ng/mL) or triiodothyronine (T3, 100 ng/mL). RNA was extracted and relative quantitative RT-PCR was performed with primers for long form leptin receptor. Receptor expression was calculated relative to 18S rRNA. Insulin had no effect (P > 0.05), while T3 increased leptin receptor mRNA abundance (P < 0.05). Treatment with GH or IGF-I reduced leptin receptor expression (P < 0.05). Phosphorylation of ERK1/2 in response to acute leptin treatment was inhibited by previous exposure to GH or IGF-I. Hepatocytes secreted IGF-I under basal conditions and this was enhanced by GH addition. These data suggest porcine hepatocytes may be less sensitive to leptin stimulation due to the actions of endogenous IGF-I on leptin receptor expression.  相似文献   

7.
BackgroundEsophageal cancer is the seventh leading cause of cancer death in males in USA, and there is a strong link has been demonstrated between inflammation and esophageal cancer, interleukin (IL)-32 is a recently described pro-inflammatory cytokine characterized by the induction of nuclear factor NF-κB activation, the p38MAPK also plays an important role in key cellular processes related to inflammation and cancer. We investigated whether the IL-32 expression may be involved in esophageal carcinogenesis through modulates the activity of NF-κB and p-p38 MAPK.MethodMalignant esophageal tissue and blood samples were obtained from 65 operated untreated patients, normal samples was obtained from 35 patients operated for other reasons as control. IL-32 expression visualized by immunohistochemistry, Real time RT–PCR for IL-32 mRNA expression, NF-κB phosphorylation and phosphorylated p38mapk were analyzed by immunoblotting, ELISA for further detection IL-32 and cytokines (TNF-α, IL-1β, IL-6 and IL-8) concentration in the patient’s sera.ResultsIL-32 expression was increased in immunohistochemical staining for malignant esophageal tissue and it’s correlated with the relative expression level of IL-32 mRNA P = 0.007, the P-NF-κB level elevated in tumor tissue compared with control and no difference in the total NF-κB level P = 0.003 while the IL-32 up-regulated the P-pNF-κB in the esophageal tumor P = 0.005. There is increase in p-p38MAPK activation underlying IL-32 expression in tumor P = 0.004, but no change in total p38 MAPK in malignant esophagus. The plasma level of IL-32 expression was increased in malignant esophageal patients P = 0.01, with increased in the levels of the cytokines TNF-α, IL-6, and IL-1β P<0.05.ConclusionsUnderstanding the pathway of IL-32 expression to stimulate the secretion cytokines via the activation of NF-κB and up-regulation of p-p38MAPK may or may not prove to be a therapeutic target, or a biomarker, and future studies will finally answer this hypothesis generated.  相似文献   

8.
Mitogen-activated protein kinases (MAPKs) are a group of cytoplasmic phosphoproteins that constitute the central core of the signalling network to respond to stress in most organisms. Their role in stress responses has been extensively studied in organisms from yeast to humans, and recently, their presence has also been described in higher plants as well as in micro- and macroalgae. In this study, we demonstrate via short experiments (1 h in duration), the rapid activation of two MAPKs similar to p38 and JNK of mammalian cells, in the Arctic kelps Laminaria solidungula and Saccharina latissima exposed to temperature and UV stress. The molecular mass of p38 is 40 kDa in L. solidungula and 42 kDa in S. latissima, while two JNKs were detected in both species, of 36 and 42 kDa in L. solidungula, and 36 and 40 kDa in S. latissima. These MAPKs are highly phosphorylated in response to temperature and UV light. In S. latissima, both p38 and the JNK showed higher phosphorylation at 2 °C than at 7 °C, while the reverse response was shown for L. solidungula. In addition, a significant increase in phosphorylation of both kinases was found following exposure to UV radiation (UVR). Exposure to PAR + UVA + UVB induced higher phosphorylation than PAR + UVA in L. solidungula, especially at 7 °C. In S. latissima, this response occurred only with JNK, and no differences in p38 phosphorylation between PAR + UVA and PAR + UVA + UVB at any temperature were observed. These results indicate the possible participation of MAPK-like proteins in response to stress in Arctic kelps, and that their activation is species-specific.  相似文献   

9.
Macrophages play a critical role in inflammation and antigen-presentation. Abnormal macrophage function has been attributed in autoimmune diseases and cancer progression. Recent evidence suggests that high salt tissue micro-environment causes changes in macrophage activation. In our current report, we studied the role of extracellular sodium chloride on phenotype changes in peripheral circulating monocyte/macrophages collected from healthy donors. High salt (0.2 M NaCl vs basal 0.1 M NaCl) treatment resulted in a decrease in MΦ1 macrophage phenotype (CD11b+CD14highCD16low) from 77.4±6.2% (0.1 M) to 29.3±5.7% (0.2 M, p<0.05), while there was an increase in MΦ2 macrophage phenotype (CD11b+ CD14lowCD16high) from 17.2±5.9% (0.1 M) to 67.4±9.4% (0.2 M, p<0.05). ELISA-based cytokine analysis demonstrated that high salt treatment induced decreased expression of in the MΦ1 phenotype specific pro-inflammatory cytokine, TNFα (3.3 fold), IL-12 (2.3 fold), CCL-10 (2 fold) and CCL-5 (3.8 fold), but conversely induced an enhanced expression MΦ2-like phenotype specific anti-inflammatory cytokine, IL-10, TGFβ, CCL-17 (3.7 fold) and CCR-2 (4.3 fold). Further high salt treatment significantly decreased phagocytic efficiency of macrophages and inducible nitric oxide synthetase expression. Taken together, these data suggest that high salt extracellular environment induces an anti-inflammatory MΦ2-like macrophage phenotype with poor phagocytic and potentially reduced antigen presentation capacity commonly found in tumor microenvironment.  相似文献   

10.
Previous studies have demonstrated increased expression and raised levels of human β-defensin (hBD)-1 in gingival tissue and crevicular fluid of patients with chronic periodontitis and peri-implantitis, oral bone-resorbing diseases caused by enhanced osteoclastogenesis. Therefore, we aimed to investigate the effect of hBD-1 on osteoclast formation and function and to elucidate the involved signaling pathway in vitro. Human peripheral blood mononuclear cells (PBMCs) were first incubated with various doses of hBD-1 and cell viability was assayed by MTT. PBMCs were treated with macrophage-colony stimulating factor and receptor activator of nuclear factor kappa-B ligand (RANKL) in the presence or absence of non-toxic doses of hBD-1. In vitro osteoclastogenesis was analyzed by tartrate-resistant acid phosphatase (TRAP) staining, osteoclast-specific gene expression, and a resorption pit assay. Involvement of mitogen-activated protein kinases (MAPKs) was studied by immunoblotting and specific MAPK inhibitors. HBD-1 potentiated induction of in vitro osteoclastogenesis by RANKL, as shown by significantly increased number of TRAP-positive multinuclear cells and resorption areas on the dentin slices, and further up-regulated expressions of osteoclast-specific genes compared to those by RANKL treatment (p < 0.05). However, hBD-1 treatment without RANKL failed to induce formation of osteoclast-like cells. A significant and further increase in transient phosphorylation of the p44/42 MAPKs was demonstrated by hBD-1 co-treatment (p < 0.05), consistent with the inhibitory effect by pretreatment with U0126 or PD98059 on hBD-1-enhanced osteoclastogenesis. Collectively, hBD-1 potentiates the induction of in vitro osteoclastogenesis by RANKL via enhanced phosphorylation of the p44/42 MAPKs.  相似文献   

11.
Kinetics of cellulose hydrolysis with halostable cellulase from a marine Aspergillus niger was analyzed at different salinities. Cellulase activity in 8% NaCl solution was 1.43 folds higher than that in NaCl free solution. Half saturation constant, Km (15.6260 g/L) and the rate constant of deactivation, Kde (0.3369 g/L h) in 8% NaCl solution was lower than that (18.6364 g/L), 0.3754 (g/L h) in NaCl free solution. The maximum initial hydrolysis velocity, Vmax (25.5295 g/L h), in 8% NaCl solution was higher than that in NaCl free solution (25.0153 g/L h). High salinity increased affinity to the cellulase to the substrate and thermostability. Halostable cellulase from a marine Aspergillus niger was valuable for cellulose hydrolysis under high salinity conditions.  相似文献   

12.
13.
The protein tyrosine phosphatases (PTPs) SHP-1, SHP-2 and PTP1B are overexpressed early on during the development of cerulein -induced acute pancreatitis (AP) in rats, and their levels can be modulated by some species of mitogen-activated protein kinases (MAPKs), the intracellular levels of cAMP and by general leukocyte infiltration, the latter at least for SHP-2 and PTP1B. In this study we show that cerulein treatment activates extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) but not p38 MAPK during the early phase of cerulein-induced AP (2 h after the first injection of cerulein). Therefore, by using the MAPK inhibitors SP600125 (a specific JNK inhibitor) and PD98059 (a specific ERK inhibitor), we have unmasked the particular MAPK that underlies the modulation of the expression levels of these PTPs. JNK would act by preventing SHP-1 protein expression from increasing beyond a certain level. ERK 1/2 was the main MAPK involved in the increase in SHP-2 protein expression due to cerulein. JNK negatively modulated the SH2-domain containing PTPs. Both MAPKs played a role in the increase in PTP1B protein expression due to cerulein. Finally, by using the white blood cell inhibitors vinblastine sulfate, gadolinium chloride and FK506 (tacrolimus), we show that the macrophage activity or T-lymphocytes does not modulate the expression of any of the PTPs, although neutrophil infiltration was found to be a regulator of SHP-2 and PTP1B protein expression due to cerulein.  相似文献   

14.
The impact of acid mine drainage (AMD) on a regional stream was evaluated using chemical analysis, biotic/ecological integrity (IBI), and habitat assessments along with the necropsy-based tissue analysis. In situ remediation tests were conducted for wastewater treatment using waste oyster shells. Monsoon rains caused the sloughing of AMD sediments, resulting in high acidity and turbidity. Friedman's two-way ANOVA showed that IBI values were significantly (p < 0.05) lower in the AMD-impacted sites than in the control and had an inverse relationship with pH. Tissue analysis revealed that all of the treatments, T1–T3, caused significant tissue damage (ANOVA; F = 11.949, p < 0.008), compared to the control. The in situ water treatment plant neutralized acid and removed 85–99% of Fe, Al, and Zn ions (χ2 = 4.0–11.1, p < 0.05). Together, these approaches may be used as a key methodology for the integrative assessment and treatment of AMD-impacted water.  相似文献   

15.
Seedlings of Pistacia vera L. and Pistacia atlantica Desf. were cultured on hormone-free DKW medium supplemented with NaCl. The plants were subjected to low NaCl concentrations ranging from 0 to 80 mM for 45 days or to high salt concentrations (0, 131, and 158.5 mM for P. vera and 0, 131, and 240 mM for P. atlantica) for 25 days. Toxicity symptoms were recorded for seedlings exposed to low NaCl treatments. Plant growth, survival rates, mineral content, as well as proline and soluble sugar contents were determined and evaluated at the end of the culture period. The results indicated that low NaCl treatments yielded no instances of plant death in both species. At high salt conditions, however, significant mortality rates were noted for both species, being 22.86% at 240 mM NaCl for P. atlantica and 25.8% at 158.5 mM NaCl for P. vera. With regards to salinity effects, levels of 60 and 80 mM NaCl induced significant decreases of stem elongation and leaf number in the P. vera species. Salinities between 40 and 80 mM NaCl, however, induced a decrease in the root number of both species. The fresh weights of P. vera and P. atlantica also decreased significantly after 45 days of culture at NaCl concentrations between 40 and 80 mM and after 25 days of culture at 158.5 and 240 mM NaCl, respectively. The sodium and chloride uptake in plant organs seemed to be controlled more efficiently in P. atlantica than in P. vera. In both species, the K+ content was noted to undergo a significant decrease when salinity increased. While the K+/Na+ ratio was maintained above 2 at low NaCl treatments, it was sharply decreased at high NaCl conditions, suggesting a failure of K–Na selectivity mechanism. The Ca2+/Na+ ratio decreased significantly at 60 and 80 mM NaCl in P. vera and at 60 mM NaCl for P. atlantica. In both Pistacia species, high NaCl treatments (131–240 mM NaCl) induced a significant increase in proline content.  相似文献   

16.
Salvia mirzayanii is a medicinal and aromatic plant belonging to the Lamiaceae family, which is an endemic plant in Iran. In this study, the effects of different salt concentrations on total phenolic content, antioxidant activities and volatile components of the aerial parts of S. mirzayanii were studied. The results showed that total phenolic content increased with the increase in salt concentration. The increase was more pronounced under moderate salinity (3.8 mg GAE g 1 DW at 6.8 dS m 1 NaCl). Plants grown at 6.8 dS m 1 NaCl displayed the highest DPPH˚ scavenging activity with the lowest IC50 value (2.13 mg ml 1) compared to the control. The volatile components were identified and analyzed by HS (headspace)-GC–MS using the Combi PAL System technique. The main components of control plants were α-terpinyl acetate, 1,8-cineole and bicyclogermacrene. The proportions of these main compounds were differently affected by salinity stress. The results showed that the synthesis of both total phenolic and some important volatile components was induced by moderate salinity.  相似文献   

17.
《Peptides》2012,33(12):2452-2458
Recent studies suggest that both osteopontin and urotensin II (UII) play critical roles in vascular remodeling. We previously showed that UII could stimulate the migration of aortic adventitial fibroblasts. In this study, we examined whether osteopontin is involved in UII-induced migration of rat aortic adventitial fibroblasts and examined the effects and mechanisms of UII on osteopontin expression in adventitial fibroblasts. Migration of adventitial fibroblasts induced by UII could be inhibited significantly by osteopontin antisense oligonucleotide (P < 0.01) but not sense or mismatch oligonucleotides (P > 0.05). Moreover, UII dose- and time-dependently promoted osteopontin mRNA expression and protein secretion in the cells, with maximal effect at 10−8 mol/l at 3 h for mRNA expression or at 12 h for protein secretion (both P < 0.01). Furthermore, the UII effects were significantly inhibited by its receptor antagonist SB710411 (10−6 mol/l), and Ca2+ channel blocker nicardipine (10−5 mol/l), protein kinase C (PKC) inhibitor H7 (10−5 mol/l), calcineurin inhibitor cyclosporine A (10−5 mol/l), mitogen-activated protein kinase (MAPK) inhibitor PD98059 (10−5 mol/l) and Rho kinase inhibitor Y-27632 (10−5 mol/l). Thus, osteopontin is involved in the UII-induced migration of adventitial fibroblasts, and UII could upregulate osteopontin gene expression and protein synthesis in rat aortic adventitial fibroblasts by activating its receptor and the Ca2+ channel, PKC, calcineurin, MAPK and Rho kinase signal transduction pathways.  相似文献   

18.
This study sought to investigate the anti-fibrotic effect of Corilagin via interference with the miR-21/smad7/ERK signaling pathway in a schistosomiasis-induced hepatic fibrosis mouse model. Mice were infected with Schistosoma japonicum cercaria to establish the mouse model of schistosomiasis-induced hepatic fibrosis. At four weeks after infection, the groups were given different medications. The living conditions were observed. Real-time PCR was employed to detect the mRNA levels of miR-21, smad7 and connective tissue growth factor (CTGF), and western blotting was used to examine the protein levels of smad7, CTGF, smad1, p-smad1, smad2, p-smad2, ERK1/2, p-ERK1/2 and TGF-β receptor I. Immunohistochemistry was used to examine the expression of CTGF. Compared with the model group, increasing concentrations of Corilagin improved the quality of life, inhibited the mRNA expression of miR-21, promoted smad7 protein expression, and inhibited CTGF protein expression (p < 0.05 or 0.01). Moreover, Corilagin significantly reduced the protein levels of p-smad1, p-smad2, p-ERK1/2, and TGF-β receptor I (p < 0.05 or 0.01). CTGF staining in the cytoplasm was markedly decreased by Corilagin (p < 0.05 or 0.01). In conclusion, Corilagin inhibited schistosomiasis-induced hepatic fibrosis via the miR21/smad7/ERK pathway in this animal model.  相似文献   

19.
《Journal of Asia》2014,17(3):221-227
Octopamine (OA) and tyramine (TA) are biogenic amines that act as neurotransmitters, neurohormones, and neuromodulators in the invertebrate nervous system. Tyramine-β-hydroxylase (TβH) catalyzes the biosynthesis of OA from TA. In this study, cDNA encoding Bombyx mori TβH (BmTβH) was cloned from the brain of the silkworm B. mori. The BmTβH mRNA comprised 2204 nucleotide residues and contained an open reading frame encoding 592 amino acids. The deduced amino acid sequence shared homology to several proteins belonging to the insect TβH family. Functional expression of the cloned cDNA was obtained using a B. mori baculovirus expression vector system. Western blot analysis revealed an immunoreactive band with a molecular mass of ~ 67.4 kDa. Reverse-phase high-performance liquid chromatography (HPLC) was used to identify the products formed during incubation of the enzyme reaction mixture. The optimum pH and temperature for the conversion of TA to OA were 7.5 and 25 °C, respectively. During incubation, the reaction was linear for the first 30 min at 25 °C and pH 7.5. Inhibitory experiments carried out with various concentrations of an inhibitor showed that this method can be used for screening of BmTβH inhibitors.  相似文献   

20.
This study was carried out to determine the median lethal concentrations (LC50) of Zinc nanoparticles (ZnNPs) on Oreochromis niloticus and Tilapia zillii. The biochemical and molecular potential effects of ZnNPs (500 and 2000 μg L−1) on the antioxidant system in the brain tissue of O. niloticus and T. zillii were investigated. Four hundred fish were used for acute and sub-acute studies. ZnNP LC50 concentrations were investigated in O. niloticus and T. zillii. The effect of 500 and 2000 μg L−1 ZnNPs on brain antioxidants of O. niloticus and T. zillii was investigated. The result indicated that 69 h LC50 was 5.5 ± 0.6 and 5.6 ± 0.4 for O. nilotica and T. zillii, respectively. Fish exposed to 500 μg L−1 ZnNPs showed a significant increase in reduced glutathione (GSH), total glutathione (tGSH) levels, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activity and gene expression. On the contrary, malondialdehyde (MDA) levels significantly decreased. Meanwhile, fish exposed to 2000 μg L−1 ZnNPs showed a significant decrease of GSH, tGSH levels, SOD, CAT, GR, GPx and GST activity and gene expression. On the contrary, MDA levels significantly increased. It was concluded that, the 96 h LC50 of ZnNPs was 5.5 ± 0.6 and 5.6 ± 0.4 for O. nilotica and T. zillii, respectively. ZnNPs in exposure concentrations of 2000 μg/L induced a deleterious effect on the brain antioxidant system of O. nilotica and T. zillii. In contrast, ZnNPs in exposure concentrations of 500 μg L−1 produced an inductive effect on the brain antioxidant system of O. nilotica and T. zillii.  相似文献   

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