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2.
《Biochemical and biophysical research communications》2013,431(2):239-245
Application of fluid pressure (FP) using pressurized fluid flow suppresses the L-type Ca2+ current through both enhancement of Ca2+ release and intracellular acidosis in ventricular myocytes. As FP-induced intracellular acidosis is more severe during the inhibition of Na+–H+ exchange (NHE), we examined the possible role of NHE in the regulation of ICa during FP exposure using HOE642 (cariporide), a specific NHE inhibitor. A flow of pressurized (∼16 dyn/cm2) fluid was applied onto single rat ventricular myocytes, and the ICa was monitored using a whole-cell patch-clamp under HEPES-buffered conditions. In cells pre-exposed to FP, additional treatment with HOE642 dose-dependently suppressed the ICa (IC50 = 0.97 ± 0.12 μM) without altering current–voltage relationships and inactivation time constants. In contrast, the ICa in control cells was not altered by HOE642. The HOE642 induced a left shift in the steady-state inactivation curve. The suppressive effect of HOE642 on the ICa under FP was not altered by intracellular high Ca2+ buffering. Replacement of external Cl− with aspartate to inhibit the Cl−-dependent acid loader eliminated the inhibitory effect of HOE642 on ICa. These results suggest that NHE may attenuate FP-induced ICa suppression by preventing intracellular H+ accumulation in rat ventricular myocytes and that NHE activity may not be involved in the Ca2+-dependent inhibition of the ICa during FP exposure. 相似文献
3.
《Cell calcium》2017
Recent studies have implicated a relationship between RhoA/ROCK activity and defective Ca2+ homeostasis in hypertrophic hearts. This study investigated molecular mechanism underlying ROCK inhibition-mediated cardioprotection against pressure overload-induced cardiac hypertrophy, with a focus on Ca2+ homeostasis.Cardiac hypertrophy model was established by performing transverse aortic constriction (TAC) in 8-week-old male rats. Groups were assigned as SHAM, TAC and TAC + Fas (rats undergoing TAC and treated with fasudil). Rats in the TAC + Fas group were administered fasudil (5 mg/kg/day), and rats in the SHAM and TAC groups were treated with vehicle for 10 weeks. Electrophysiological recordings were obtained from isolated left ventricular myocytes and expression levels of proteins were determined using western blotting. Rats in the TAC group showed remarkable cardiac hypertrophy, and fasudil treatment significantly reversed this alteration. TAC + Fas myocytes showed significant improvement in reduced contractility and Ca2+ transients. Moreover, these myocytes showed restoration of slow relaxation rate and Ca2+ reuptake. Although L-type Ca2+ currents did not change in TAC group, there was a significant reduction in the triggered Ca2+ transients which was reversed either by long-term fasudil treatment or incubation of TAC myocytes with fasudil. The hearts of rats in the TAC group showed a significant decrease in ROCK1, ROCK2, RyR2 protein levels and p-PLBS16/T17/SERCA2 ratio and increase in RhoA expression and MLC phosphorylation. However, fasudil treatment largely reversed TAC-induced alterations in protein expression.Thus, our findings indicate that upregulation of the RhoA/ROCK pathway is significantly associated with cardiac hypertrophy-related Ca2+ dysregulation and suggest that ROCK inhibition prevents hypertrophic heart failure. 相似文献
4.
Anand Rotte Melanie Eichenmüller Michael Föller 《Biochemical and biophysical research communications》2010,398(4):677-510
AMP-activated protein kinase (AMPK) is activated upon energy depletion and serves to restore energy balance by stimulating energy production and limiting energy utilization. Specifically, it enhances cellular glucose uptake by stimulating GLUT and SGLT1 and glucose utilization by stimulating glycolysis. During O2 deficiency glycolytic degradation of glucose leads to formation of lactate and H+, thus imposing an acid load to the energy-deficient cell. Cellular acidification inhibits glycolysis and thus impedes glucose utilization. Maintenance of glycolysis thus requires cellular H+ export. The present study explored whether AMPK influences Na+/H+ exchanger (NHE) activity and/or Na+-independent acid extrusion. NHE1 expression was determined by RT-PCR and Western blotting. Cytosolic pH (pHi) was estimated utilizing BCECF fluorescence and Na+/H+ exchanger activity from the Na+-dependent re-alkalinization (ΔpHi) after an ammonium pulse. As a result, human embryonic kidney (HEK) cells express NHE1. The pHi and ΔpHi in those cells were significantly increased by treatment with AMPK stimulator AICAR (1 mM) and significantly decreased by AMPK inhibitor compound C (10 μM). The effect of AICAR on pHi and ΔpHi was blunted in the presence of the Na+/H+ exchanger inhibitor cariporide (10 μM), but not by the H+ ATPase inhibitor bafilomycin (10 nM). AICAR significantly enhanced lactate formation, an effect significantly blunted in the presence of cariporide. These observations disclose a novel function of AMPK, i.e. regulation of cytosolic pH. 相似文献
5.
The Malpighian (renal) tubules play important roles in ionic and osmotic homeostasis in insects. In Lepidoptera, the Malpighian tubules are structurally regionalized and the concentration of Na+ and K+ in the secreted fluid varies depending on the segment of tubule analyzed. In this work, we have characterized fluid and ion (Na+, K+, H+) transport by tubules of the larval stage of the cabbage looper Trichoplusia ni; we have also evaluated the effects of fluid secretion inhibitors and stimulants on fluid and ion transport. Ramsay assays showed that fluid was secreted by the iliac plexus but not by the yellow and white regions of the tubule. K+ and Na+ were secreted by the distal iliac plexus (DIP) and K+ was reabsorbed in downstream regions. The fluid secretion rate decreased > 50% after 25 μM bafilomycin A1, 500 μM amiloride or 50 μM bumetanide was added to the bath. The concentration of K+ in the secreted fluid did not change, whereas the concentration of Na+ in the secreted fluid decreased significantly when tubules were exposed to bafilomycin A1 or amiloride. Addition of 500 μM cAMP or 1 μM 5-HT to the bath stimulated fluid secretion and resulted in a decrease in K+ concentration in the secreted fluid. An increase in Na+ concentration in the secreted fluid was observed only in cAMP-stimulated tubules. Secreted fluid pH and the transepithelial electrical potential (TEP) did not change when tubules were stimulated. Taken together, our results show that the secretion of fluid is carried out by the upper regions (DIP) in T. ni Malpighian tubules. Upper regions of the tubules secrete K+, whereas lower regions reabsorb it. Stimulation of fluid secretion is correlated with a decrease in the K+/Na+ ratio. 相似文献
6.
Wen-Ting Xu Ning Jin Jing Xu Yun-Gen Xu Qiu-Juan Wang Qi-Dong You 《Bioorganic & medicinal chemistry letters》2009,19(12):3283-3287
A novel series of substituted benzoylguanidine derivatives were designed and synthesized as potent NHE1 inhibitors. Most compounds can significantly inhibit NHE1-mediated platelet swelling in a concentration-dependent manner, among which compound 5f (IC50 = 3.60 nM) and 5l (IC50 = 4.48 nM) are 18 and 14 times respectively more potent than cariporide (IC50 = 65.0 nM). Furthermore, when tested in vivo and in vitro, compound 5f showed superior cardioprotective effects against SD rat myocardial ischemic-reperfusion injury over cariporide, representing a promising lead compound for further exploration. 相似文献
7.
Zen-Kong Dai Yung-Jen Cheng Hui-Hsuan Chung Jiunn-Ren Wu Ing-Jun Chen Bin-Nan Wu 《Life sciences》2010,86(19-20):747-755
AimsThis study investigates the actions of KMUP-1 on RhoA/Rho-kinase (ROCK)-dependent Ca2+ sensitization and the K+-channel in chronic pulmonary arterial hypertension (PAH) rats.Main methodsSprague–Dawley rats were divided into control, monocrotaline (MCT), and MCT + KMUP-1 groups. PAH was induced by a single intraperitoneal injection (i.p.) of MCT (60 mg/kg). KMUP-1 (5 mg/kg, i.p.) was administered once daily for 21 days to prevent MCT-induced PAH. All rats were sacrificed on day 22.Key findingsMCT-induced increased right ventricular systolic pressure (RVSP) and right ventricular hypertrophy were prevented by KMUP-1. In myograph experiments, KCl (80 mM), phenylephrine (10 µM) and K+ channel inhibitors (TEA, 10 mM; paxilline, 10 µM; 4-AP, 5 mM) induced weak PA contractions in MCT-treated rats compared to controls, but the PA reactivity was restored in MCT + KMUP-1-treated rats. By contrast, in β-escin- or α-toxin-permeabilized PAs, CaCl2-induced (1.25 mM, pCa 5.1) contractions were stronger in MCT-treated rats, and this action was suppressed in MCT + KMUP-1-treated rats. PA relaxation in response to the ROCK inhibitor Y27632 (0.1 μM) was much higher in MCT-treated rats than in control rats. In Western blot analysis, the expression of Ca2+-activated K+ (BKCa) and voltage-gated K+ channels (Kv2.1 and Kv1.5), and ROCK II proteins was elevated in MCT-treated rats and suppressed in MCT + KMUP-1-treated rats. We suggest that MCT-treated rats upregulate K+-channel proteins to adapt to chronic PAH.SignificanceKMUP-1 protects against PAH and restores PA vessel tone in MCT-treated rats, attributed to alteration of Ca2+ sensitivity and K+-channel function. 相似文献
8.
Bhawana Agarwal Amadou K.S. Camara David F. Stowe Zeljko J. Bosnjak Ranjan K. Dash 《BBA》2012,1817(3):453-465
Modulation of mitochondrial free Ca2 + ([Ca2 +]m) is implicated as one of the possible upstream factors that initiates anesthetic-mediated cardioprotection against ischemia–reperfusion (IR) injury. To unravel possible mechanisms by which volatile anesthetics modulate [Ca2 +]m and mitochondrial bioenergetics, with implications for cardioprotection, experiments were conducted to spectrofluorometrically measure concentration-dependent effects of isoflurane (0.5, 1, 1.5, 2 mM) on the magnitudes and time-courses of [Ca2 +]m and mitochondrial redox state (NADH), membrane potential (ΔΨm), respiration, and matrix volume. Isolated mitochondria from rat hearts were energized with 10 mM Na+- or K+-pyruvate/malate (NaPM or KPM) or Na+-succinate (NaSuc) followed by additions of isoflurane, 0.5 mM CaCl2 (≈ 200 nM free Ca2 + with 1 mM EGTA buffer), and 250 μM ADP. Isoflurane stepwise: (a) increased [Ca2 +]m in state 2 with NaPM, but not with KPM substrate, despite an isoflurane-induced slight fall in ΔΨm and a mild matrix expansion, and (b) decreased NADH oxidation, respiration, ΔΨm, and matrix volume in state 3, while prolonging the duration of state 3 NADH oxidation, respiration, ΔΨm, and matrix contraction with PM substrates. These findings suggest that isoflurane's effects are mediated in part at the mitochondrial level: (1) to enhance the net rate of state 2 Ca2 + uptake by inhibiting the Na+/Ca2 + exchanger (NCE), independent of changes in ΔΨm and matrix volume, and (2) to decrease the rates of state 3 electron transfer and ADP phosphorylation by inhibiting complex I. These direct effects of isoflurane to increase [Ca2 +]m, while depressing NCE activity and oxidative phosphorylation, could underlie the mechanisms by which isoflurane provides cardioprotection against IR injury at the mitochondrial level. 相似文献
9.
Melissa A. Liriano Kristen M. Varney Nathan T. Wright Cassandra L. Hoffman Eric A. Toth Rieko Ishima David J. Weber 《Journal of molecular biology》2012,423(3):365-385
Mutations in the second EF-hand (D61N, D63N, D65N, and E72A) of S100B were used to study its Ca2 + binding and dynamic properties in the absence and presence of a bound target, TRTK-12. With D63NS100B as an exception (D63NKD = 50 ± 9 μM), Ca2 + binding to EF2-hand mutants were reduced by more than 8-fold in the absence of TRTK-12 (D61NKD = 412 ± 67 μM, D65NKD = 968 ± 171 μM, and E72AKD = 471 ± 133 μM), when compared to wild-type protein (WTKD = 56 ± 9 μM). For the TRTK-12 complexes, the Ca2 +-binding affinity to wild type (WT + TRTKKD = 12 ± 10 μM) and the EF2 mutants was increased by 5- to 14-fold versus in the absence of target (D61N + TRTKKD = 29 ± 1.2 μM, D63N + TRTKKD = 10 ± 2.2 μM, D65N + TRTKKD = 73 ± 4.4 μM, and E72A + TRTKKD = 18 ± 3.7 μM). In addition, Rex, as measured using relaxation dispersion for side‐chain 15N resonances of Asn63 (D63NS100B), was reduced upon TRTK-12 binding when measured by NMR. Likewise, backbone motions on multiple timescales (picoseconds to milliseconds) throughout wild type, D61NS100B, D63NS100B, and D65NS100B were lowered upon binding TRTK-12. However, the X-ray structures of Ca2 +-bound (2.0 Å) and TRTK-bound (1.2 Å) D63NS100B showed no change in Ca2 + coordination; thus, these and analogous structural data for the wild-type protein could not be used to explain how target binding increased Ca2 +-binding affinity in solution. Therefore, a model for how S100B–TRTK‐12 complex formation increases Ca2 + binding is discussed, which considers changes in protein dynamics upon binding the target TRTK-12. 相似文献
10.
The Na+/H+ exchanger (NHE) is a protein expressed in many mammalian cell types. It is involved in intracellular pH (pHi) homeostasis by exchanging extracellular Na+ for intracellular H+. To date, nine NHE isoforms (NHE1–NHE9) have been identified. NHE1 is the most predominant isoform expressed in mammalian cardiac muscle. A novel series of substituted (quinolinecarbonyl)guanidine derivatives were designed and synthesized as NHE inhibitors. Most compounds can inhibit NHE1‐mediated platelet swelling in a concentration‐dependent manner, among which compound 7f was the most active and more potent than cariporide. Furthermore, compound 7f has also been demonstrated to exhibit the in vivo cardioprotective effects against SD rat myocardial ischemic‐reperfusion injury superior to those of cariporide. 相似文献
11.
Čedomil Lucu Iris Dupčić-Radić Sanja Tomšić 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2009,149(4):476-480
The effect of methyl mercuric chloride (MeHg) on short-circuit current (ISC) was studied in the isolated perfused epipodite preparation from the branchial chamber of European lobster (Homarus gammarus) acclimated to dilute seawater. When applied at the apical surface, 0.2, 1.0 and 3.0 μM MeHg depressed ISC by a 26%, 81% and 98%, respectively. The half-maximal inhibitory concentration (IC50) of apically applied MeHg was 0.6 μM. Basolaterally added MeHg (3.0 μM) had no effect on ISC, whereas addition of the specific Na+,K+-ATPase inhibitor ouabain (1.5 mM) reduced ISC by ~ 90%. Ouabain effects were reversible, and ISC fully recovered upon removal of ouabain. The MeHg-induced block of ISC was partially reversed by the reducing agent, 1,4-dithiothreitol, suggesting that the formation of S–Hg–S bridges is important in the inhibitory mechanism. A significant reduction of ISC and conductance occurred when low Na+ and Cl? salines were substituted. Furthermore, in the low Na+ saline, JClA → B fluxes were reduced by about 50%. In the highly conductive epipodite epithelium, coupling of Na+ and Cl? fluxes was suggested. The effects of MeHg on ISC in the lobster epipodite are attributed to inhibition of an apical Cl? influx. 相似文献
12.
《Cell calcium》2014,55(5):231-237
Endocannabinoid anandamide (N-arachidonoyl ethanolamide; AEA) has been shown to cause negative inotropic and antiarrhythmic effects in ventricular myocytes. In this study, using whole-cell patch clamp technique, we have investigated the effects of AEA on cardiac Na+/Ca2+ exchanger (NCX1)-mediated currents. AEA suppressed NCX1 with an IC50 value of 4.7 μM. Both inward and outward components of exchanger currents were suppressed by AEA equally. AEA inhibition was mimicked by the metabolically stable analogue, methanandamide (metAEA, 10 μM) while it was not influenced by inhibition of fatty acid amide hydrolase with 1 μM URB597 incubation. The effect of AEA, was not altered in the presence of cannabinoid receptor 1 and 2 antagonists AM251 (1 μM) and AM630 (1 μM), respectively. In addition, inhibition by AEA remained unchanged after pertussis toxin (PTX, 2 μg/ml) treatment or following the inclusion of GDP-β-S (1 mM) in pipette solution. Currents mediated by NCX1 expressed in HEK-293 cells were also inhibited by 10 μM AEA a partially reversible manner. Confocal microscopy images indicated that the intensity of YFP-NCX1 expression on cell surface was not altered by AEA. Collectively, the results indicate that AEA directly inhibits the function of NCX1 in rat ventricular myocytes and in HEK-293 cells expressing NCX1. 相似文献
13.
《Aquatic Botany》2007,87(4):292-298
The effect of salinity on leaf area and the relative accumulation of Na+ and K+ in leaves of the mangrove associate Hibiscus tiliaceus were investigated. Photosynthetic gas exchange characteristics were also examined under arid and non-arid leaf conditions at 0, 10, 20 and 30‰ substrate salinity. At salinities ≥ 40‰, plants showed complete defoliation followed by 100% mortality within 1 week. Salinities ≤ 30‰ were negatively correlated with the total leaf area per plant (r2 = 0.94). The reduction in the total plant leaf area is attributed to the reduction in the area of individual leaves (r2 = 0.94). Selective uptake of K+ over Na+ declined sharply with increasing salinity, where K+/Na+ ratio was reduced from 6.37 to 0.69 in plants treated with 0 and 30‰, respectively. Under non-arid leaf condition, increasing salinity from 0 to 30‰ has significantly reduced the values of the intrinsic components of photosynthesis Vc,max (from 50.4 to 18.4 μmol m−2 s-1), Jmax (from 118.0 to 33.8 μmol photons m−2 s−1), and VTPU (from 6.90 to 2.30 μmol m−2 s−1), while stomatal limitation to gas phase conductance (SL) increased from 14.6 to 38.4%. Water use efficiency (WUE) has subsequently doubled from 3.20 for the control plants to 8.93 for 30‰ treatment. Under arid leaf conditions, the stomatal factor (SL) was more limiting to photosynthesis than its biochemical components (73.4 to 26.6%, respectively, at 30‰). It is concluded that salinity causes a drastic decline in photosynthetic gas exchange in H. tiliaceus leaves through its intrinsic and stomatal components, and that the apparent phenotypic plasticity represented by the leaf area modulation is unlikely to be the mechanism by which H. tiliaceus avoids salt stress. 相似文献
14.
《Aquatic Botany》2008,88(4):292-298
The effect of salinity on leaf area and the relative accumulation of Na+ and K+ in leaves of the mangrove associate Hibiscus tiliaceus were investigated. Photosynthetic gas exchange characteristics were also examined under arid and non-arid leaf conditions at 0, 10, 20 and 30‰ substrate salinity. At salinities ≥ 40‰, plants showed complete defoliation followed by 100% mortality within 1 week. Salinities ≤ 30‰ were negatively correlated with the total leaf area per plant (r2 = 0.94). The reduction in the total plant leaf area is attributed to the reduction in the area of individual leaves (r2 = 0.94). Selective uptake of K+ over Na+ declined sharply with increasing salinity, where K+/Na+ ratio was reduced from 6.37 to 0.69 in plants treated with 0 and 30‰, respectively. Under non-arid leaf condition, increasing salinity from 0 to 30‰ has significantly reduced the values of the intrinsic components of photosynthesis Vc,max (from 50.4 to 18.4 μmol m−2 s-1), Jmax (from 118.0 to 33.8 μmol photons m−2 s−1), and VTPU (from 6.90 to 2.30 μmol m−2 s−1), while stomatal limitation to gas phase conductance (SL) increased from 14.6 to 38.4%. Water use efficiency (WUE) has subsequently doubled from 3.20 for the control plants to 8.93 for 30‰ treatment. Under arid leaf conditions, the stomatal factor (SL) was more limiting to photosynthesis than its biochemical components (73.4 to 26.6%, respectively, at 30‰). It is concluded that salinity causes a drastic decline in photosynthetic gas exchange in H. tiliaceus leaves through its intrinsic and stomatal components, and that the apparent phenotypic plasticity represented by the leaf area modulation is unlikely to be the mechanism by which H. tiliaceus avoids salt stress. 相似文献
15.
《Aquatic Botany》2005,81(4):326-342
The effects of NH4+ or NO3− on growth, resource allocation and nitrogen (N) uptake kinetics of two common helophytes Phragmites australis (Cav.) Trin. ex Steudel and Glyceria maxima (Hartm.) Holmb. were studied in semi steady-state hydroponic cultures. At a steady-state nitrogen availability of 34 μM the growth rate of Phragmites was not affected by the N form (mean RGR = 35.4 mg g−1 d−1), whereas the growth rate of Glyceria was 16% higher in NH4+-N cultures than in NO3−-N cultures (mean = 66.7 and 57.4 mg g−1 d−1 of NH4+ and NO3− treated plants, respectively). Phragmites and Glyceria had higher S/R ratio in NH4+ cultures than in NO3− cultures, 123.5 and 129.7%, respectively.Species differed in the nitrogen utilisation. In Glyceria, the relative tissue N content was higher than in Phragmites and was increased in NH4+ treated plants by 16%. The tissue NH4+ concentration (mean = 1.6 μmol g fresh wt−1) was not affected by N treatment, whereas NO3− contents were higher in NO3− (mean = 1.5 μmol g fresh wt−1) than in NH4+ (mean = 0.4 μmol g fresh wt−1) treated plants. In Phragmites, NH4+ (mean = 1.6 μmol g fresh wt−1) and NO3− (mean = 0.2 μmol g fresh wt−1) contents were not affected by the N regime. Species did not differ in NH4+ (mean = 56.5 μmol g−1 root dry wt h−1) and NO3− (mean = 34.5 μmol g−1 root dry wt h−1) maximum uptake rates (Vmax), and Vmax for NH4+ uptake was not affected by N treatment. The uptake rate of NO3− was low in NH4+ treated plants, and an induction phase for NO3− was observed in NH4+ treated Phragmites but not in Glyceria. Phragmites had low Km (mean = 4.5 μM) and high affinity (10.3 l g−1 root dry wt h−1) for both ions compared to Glyceria (Km = 6.3 μM, affinity = 8.0 l g−1 root dry wt h−1). The results showed different plasticity of Phragmites and Glyceria toward N source. The positive response to NH4+-N source may participates in the observed success of Glyceria at NH4+ rich sites, although other factors have to be considered. Higher plasticity of Phragmites toward low nutrient availability may favour this species at oligotrophic sites. 相似文献
16.
Braga-Sobrinho C Leite-Dellova DC Mello-Aires M 《The Journal of steroid biochemistry and molecular biology》2012,128(3-5):89-97
The rapid (2 min) nongenomic effects of aldosterone (ALDO) and/or spironolactone (MR antagonist), RU 486 (GR antagonist), atrial natriuretic peptide (ANP) and dimethyl-BAPTA (BAPTA) on the intracellular pH recovery rate (pHirr) via NHE1 (basolateral Na+/H+ exchanger isoform), after the acid load induced by NH4Cl, and on the cytosolic free calcium concentration ([Ca2+]i) were investigated in the proximal S3 segment isolated from rats, by the probes BCECF-AM and FLUO-4-AM, respectively. The basal pHi was 7.15 ± 0.008 and the basal pHirr was 0.195 ± 0.012 pH units/min (number of tubules/number of tubular areas = 16/96). Our results confirmed the rapid biphasic effect of ALDO on NHE1: ALDO (10?12 M) increases the pHirr to approximately 59% of control value, and ALDO (10?6 M) decreases it to approximately 49%. Spironolactone did not change these effects, but RU 486 inhibited the stimulatory effect and maintained the inhibitory effect. ANP (10?6 M) or BAPTA (5 × 10?5 M) alone had no significant effect on NHE1 but prevented both effects of ALDO on this exchanger. The basal [Ca2+]i was 104 ± 3 nM (15), and ALDO (10?12 or 10?6 M) increased the basal [Ca2+]i to approximately 50% or 124%, respectively. RU 486, ANP and BAPTA decreased the [Ca2+]i and inhibited the stimulatory effect of both doses of ALDO. The results suggest the involvement of GR on the nongenomic effects of ALDO and indicate a pHirr-regulating role for [Ca2+]i that is mediated by NHE1, stimulated/impaired by ALDO, and affected by ANP or BAPTA with ALDO. The observed nongenomic hormonal interaction in the S3 segment may represent a rapid and physiologically relevant regulatory mechanism in the intact animal under conditions of volume alterations. 相似文献
17.
Zhi-Hua Li Vladimir Zlabek Roman Grabic Ping Li Jana Machova Josef Velisek Tomas Randak 《Chemico-biological interactions》2010,185(3):241-246
The effect of long-term (30 days) exposure to PCZ (0.2, 50, and 500 μg l?1) on intestine-related biochemical markers in rainbow trout was investigated. Multiple biomarkers were measured, including digestive enzymes (proteolytic enzymes and amylase), antioxidant responses (TBARS, CP, SOD, CAT, GR and GPx) and energy metabolic parameters (RNA/DNA ratio, Na+-K+-ATPase). Exposure to 500 μg l?1 PCZ led to significantly inhibited (p < 0.01) proteolytic enzyme and amylase activity. Activities of the antioxidant enzymes SOD, CAT, and GPx gradually increased at lower PCZ concentrations (0.2 and 50 μg l?1). At the highest concentration (500 μg l?1), oxidative stress was apparent as significant higher (p < 0.05) lipid peroxidation and protein carbonyls, associated with an inhibition of antioxidant enzymes activity. Moreover, energy metabolic parameters (RNA/DNA ratio, Na+-K+-ATPase) were significantly inhibited (p < 0.01) in the intestines of fish exposed to 500 μg l?1 PCZ, compared with controls. We suggest that long-term exposure to PCZ could result in several responses in intestine-related biochemical markers, which potentially could be used as indicators for monitoring residual PCZ present in the aquatic environment. 相似文献
18.
Elena Rodríguez José R. Peralta-Videa Mohd. Israr Shivendra V. Sahi Helvia Pelayo Blanca Sánchez-Salcido Jorge L. Gardea-Torresdey 《Environmental and Experimental Botany》2009,65(2-3):253-262
Plants of Chilopsis linearis were grown with 0, 50, 100, and 200 μM Hg [as Hg(CH3COO)2] and 0 and 50 μM Au (as KAuCl4) in hydroponics. The results showed that seedling grown with 50 μM Au + 50 μM Hg and 50 μM Au + 100 μM Hg had roots 25 and 55% shorter than control roots, respectively. The element uptake determination using ICP/OES demonstrated that Hg at 50 and 100 μM (with and without Au) significantly increased (p < 0.05) the S concentration in leaves. On the other hand, the concentration of Fe significantly increased in roots of plants treated with Au–Hg. In addition, the stems of plants treated with Hg at 100 μM, with and without Au, had 239 and 876 mg Hg/kg dry biomass (d wt), respectively. Also, at 50 μM Hg, with and without Au, stems accumulated 375 and 475 mg Hg/kg d wt. The Hg concentration in leaves (287 mg Hg/kg d wt) was higher (p < 0.05) for the treatment containing 50 μM Au + 100 μM Hg. Without Au, the Hg concentration in leaves decreased to 75 mg Hg/kg d wt. Toxicity symptoms induced by Hg in cortex cells and the vascular system were lower in plants exposed to 50 μM Au + 50 μM Hg compared to plants exposed to 50 μM Hg only. Further, the SEM micrographs revealed deposition of Au–Hg particles inside the root. Although the concentrations of Hg used in this study showed different degree of toxicity, the plants displayed good agronomic value. 相似文献
19.
《Journal of Asia》2014,17(1):67-71
While screening for cellulase-producing fungi from insect gut, a fungus with high endoglucanase (carboxymethyl cellulase; CMCase) activity was isolated from the larval gut of Bombyx mori. Based on morphological characteristics and using an 18S rRNA-based molecular phylogenetic approach, the fungus, strain BMC-2, was identified as a Mucor sp. expressing a novel alkalotolerant cellulase. The maximum production of cellulase by the BMC-2 strain was observed at 55 °C and pH 8.0. The CMCase activity was inhibited by Cu2 + > Na+ > Zn2 + > Mg2 + > Ba2 +, and induced by Ca2 +, Mn2 +, Fe2 +, and K+. 相似文献
20.
Astacus leptodactylus is a decapod crustacean fully adapted to freshwater where it spends its entire life cycle after hatching under huge osmoconcentration differences between the hemolymph and surrounding freshwater. We investigated the expression of mRNA encoding one ion transport-related protein, Na+/K+-ATPase α-subunit, and one putative housekeeping gene, β-actin, during crayfish ontogenesis using quantitative real-time PCR. A 216-amino acid part of the open reading frame region of the cDNA coding for the Na+/K+-ATPase α-subunit was sequenced from total embryo, juvenile and adult gill tissues. The predicted amino acid sequence showed a high percentage similarity to those of other invertebrates (up to 95%) and vertebrates (up to 69%). β-actin expression exhibited modest changes through embryonic development and early post-embryonic stage. The Na+/K+-ATPase α-subunit gene was expressed in all studied stages from metanauplius to juvenile. Two peaks of expression were observed: one in young embryos at 25% of embryonic development (EI = 100 μm), and one in embryos just before hatching (at EI = 420 μm), continuing in the freshly hatched juveniles. The Na+/K+-ATPase expression profile during embryonic development is time-correlated with the occurrence of other features, including ontogenesis of excretory antennal glands and differentiation of gill ionocytes linked to hyperosmoregulation processes and therefore involved in freshwater adaptation. 相似文献