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1.
The principal active constituent of the botanical drug candidate PBI-05204, a supercritical CO(2) extract of Nerium oleander, is the cardiac glycoside oleandrin. PBI-05204 shows potent anticancer activity and is currently in phase I clinical trial as a treatment for patients with solid tumors. We have previously shown that neriifolin, which is structurally related to oleandrin, provides robust neuroprotection in brain slice and whole animal models of ischemic injury. However, neriifolin itself is not a suitable drug development candidate and the FDA-approved cardiac glycoside digoxin does not cross the blood-brain barrier. We report here that both oleandrin as well as the full PBI-05204 extract can also provide significant neuroprotection to neural tissues damaged by oxygen and glucose deprivation as occurs in ischemic stroke. Critically, we show that the neuroprotective activity of PBI-05204 is maintained for several hours of delay of administration after oxygen and glucose deprivation treatment. We provide evidence that the neuroprotective activity of PBI-05204 is mediated through oleandrin and/or other cardiac glycoside constituents, but that additional, non-cardiac glycoside components of PBI-05204 may also contribute to the observed neuroprotective activity. Finally, we show directly that both oleandrin and the protective activity of PBI-05204 are blood brain barrier penetrant in a novel model for in vivo neuroprotection. Together, these findings suggest clinical potential for PBI-05204 in the treatment of ischemic stroke and prevention of associated neuronal death. 相似文献
2.
Estrogen and progesterone, while regulating uterine functions, also regulate the number of caveolae and the level of caveolin. Large numbers of caveolae, as well as elevated expression of caveolin-1 and caveolin-2 isoforms in the myometrium of ovariectomised (OVX) rats were detected. 17beta-estradiol (E2) has a downregulating effect: the treatment of OVX rats with E2 (5 microg/animal) reduced the formation of caveolae by approx. 90%. Western blots clearly demonstrated the reduction of membrane caveolin-1 and -2 content. Progesterone treatment (2.5 mg/animal) alone did not cause any substantial change, but prevented the effect of estrogen. Control experiments showed that the quantity of Na+/K+-ATPase, a plasma membrane protein excluded from caveolae, was not downregulated by E2. The administration of the pure estrogen receptor (ERalpha) antagonist ICI 182,780 (1 mg/animal) not only compensated for the inhibitory effect of E2, but further increased the level of caveolin-1 in the myometrium of OVX rats and facilitated the formation of caveolae by approximately 70%. In contrast, the partial antagonist tamoxifen (1 mg/animal) mimicked the effect of estrogen. The amount of caveolin also changed during pregnancy. During the first half of pregnancy the expression of caveolin was suppressed, but it gradually increased until delivery. Our results indicate that the formation and number of caveolae are influenced by the physiological state of the uterus in a hormone dependent manner. 相似文献
3.
S. Ferrando † M. Bottaro ‡ L. Gallus L. Girosi M. Vacchi ‡ G. Tagliafierro 《Journal of fish biology》2006,69(SB):278-282
Na+ /K+ ATPase immunoreactivity in olfactory epithelium of Scyliorhinus canicula was localized in well featured light large cells. It was distributed in the basolateral membranes as reported in the literature for typical ion exchanging cells. 相似文献
4.
Jonas Lindholt Gregersen Daniel Mattle Natalya U. Fedosova Poul Nissen Linda Reinhard 《Acta Crystallographica. Section F, Structural Biology Communications》2016,72(4):282-287
Na+,K+‐ATPase is responsible for the transport of Na+ and K+ across the plasma membrane in animal cells, thereby sustaining vital electrochemical gradients that energize channels and secondary transporters. The crystal structure of Na+,K+‐ATPase has previously been elucidated using the enzyme from native sources such as porcine kidney and shark rectal gland. Here, the isolation, crystallization and first structure determination of bovine kidney Na+,K+‐ATPase in a high‐affinity E2–BeF3−–ouabain complex with bound magnesium are described. Crystals belonging to the orthorhombic space group C2221 with one molecule in the asymmetric unit exhibited anisotropic diffraction to a resolution of 3.7 Å with full completeness to a resolution of 4.2 Å. The structure was determined by molecular replacement, revealing unbiased electron‐density features for bound BeF3−, ouabain and Mg2+ ions. 相似文献
5.
Among tetrapods, evidence for postrenal modification of the urine by the distal digestive tract (including the colon and cloaca) is highly variable. Birds and bladderless reptiles are of interest because the colon and cloaca represent the only sites from which water and ions can be reclaimed from the urine secreted by the kidney. For animals occupying desiccating environments (e.g., deserts and marine environments), postrenal modification of the urine may directly contribute to the maintenance of hypo‐osmotic body fluids. We compared the morphology and distribution of key proteins in the colon, cloaca, and urogenital ducts of watersnakes from marine (Nerodia clarkii clarkii) and freshwater (Nerodia fasciata) habitats. Specifically, we examined the epithelia of each tissue for evidence of mucus production by examining the distribution of mucopolysaccharides, and for evidence of water/ion regulation by examining the distribution of Na+/K+‐ATPase (NKA), Na+/K+/Cl? cotransporter (NKCC), and aquaporin 3 (AQP3). NKCC localized to the basolateral epithelium of the colon, urodeal sphincter, and proctodeum, consistent with a role in secretion of Na+, Cl?, and K+ from the tissue, but NKA was not detected in the colon or any compartment of the cloaca. Interestingly, NKA was detected in the basolateral epithelium of the ureters, suggesting the urothelium may play a role in active ion transport. AQP3 was detected in the ureters and coprodeal complex, consistent with a role in urinary and fecal dehydration or, potentially, in the production of the watery component of the mucus secreted by the coprodeal complex. Since no differences in general cloacal morphology, production of mucus, or the distribution of ion transporters/water channels were detected between the two species, cloacal osmoregulation may either be regulated by proteins not examined in this study or may not be responsible for the differential success of N. c. clarkii and N. fasciata in marine habitats. J. Morphol. 2011. © 2011 Wiley Periodicals, Inc. 相似文献
6.
Malakpour Kolbadinezhad S Hajimoradloo A Ghorbani R Joshaghani H Wilson JM 《Journal of fish biology》2012,81(1):125-134
This study was carried out to determine the effects of gradual salinity increase on osmoregulatory ability of the Caspian roach Rutilus caspicus, under conditions which mimic stocking conditions of hatchery-raised fish. Initially, 30 juvenile fish (mean ± S.D. 3.20 ± 0.34 g) were transferred to 20 l circular tanks, in which salinities were changed in a stepwise fashion, from 0 to 5, 10 or 15 at 48 h intervals. The fish at salinity 15 were held for an additional 48 h at this salinity. Forty-eight hours after salinity transfer, survival rate, haematocrit, plasma Cl(-) , Na(+) and K(+) concentrations, osmolality and gill Na(+) /K(+) -ATPase (NKA) activity were measured. The only effect of exposure to 5 was a significant reduction in haematocrit compared to the freshwater control group. Exposure to salinity 10 raised haematocrit, Cl(-) and Na(+) concentrations and osmolality. At 48 h exposure to salinity 15, haematocrit, Cl(-) and Na(+) concentrations and osmolality were significantly higher than freshwater controls, and gill NKA activity was significantly lower, but the effect on NKA was no longer evident at 96 h exposure. There were no effects on survival. These results indicate that R. caspicus juveniles experience an initial non-lethal iono-osmotic perturbation following salinity increase but can adapt to brackish water at salinity 15. 相似文献
7.
Phospholipid methylation was quantified in non-diabetic and streptozotocin diabetic rat erythrocytes. While the total mass of methylated lipids remained the same in both groups, the relative abundance of individual methylated lipid species differed significantly in diabetic erythrocytes. Moreover, incubation of erythrocytes membranes with S-adenosyl methionine, a substrate for methyl transferases, not only increased membrane lipid methylation but also decreased Na+, K+ ATPase activity significantly. These results suggest that phospholipid methylation may cause the observed depression of erythrocyte Na+, K+ ATPase activity in diabetes and could contribute to the altered rheology of erythrocytes in diabetes. 相似文献
8.
研究了盐胁迫对囊果碱蓬出苗、幼苗生长、离子积累以及光合放氧速率的影响.囊果碱蓬生长的最适盐浓度在200 mmol/L NaCl左右.高浓度NaCl(400 mmol/L和600 mmol/L)没有显著降低其出苗率,200 mmol/L NaCl对出苗率具有促进作用.400 mmol/L和600 mmol/L NaCl显著降低了光合放氧速率.囊果碱蓬在高浓度NaCl处理下能够维持叶片较高的K+/Na+ 及含水量可能是其适应高盐生境的重要机制. 相似文献
9.
氯化钾对长春花盛花期盐胁迫效应和生物碱含量的影响 总被引：1，自引：0，他引：1
在温室土培条件下,研究了不同浓度KCl处理对长春花盛花期盐胁迫效应以及对文多灵、长春质碱、长春碱和长春新碱等生物碱含量的影响.结果现实:(1)3‰ NaCl胁迫下,施入一定量KCl,将Na+/K+调为20:1(K2)时可显著缓解盐胁迫对长春花的危害,与不施KCl(K1)相比,长春花的鲜质量、株高、根长和相对含水量均显著提高,而长春花叶片丙二醛含量显著下降,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性在Na+/K+为20:1(K2)时显著高于其它处理,但当Na+/K+为10:1(K3)与5:1(K4)时,盐胁迫的危害又显著加剧.(2)Na+/K+为20:1处理的长春花盛花期文多灵、长春质碱、长春碱和长春新碱含量显著高于其它处理,分别为20.88、30.18、2.53和5.12 mg·g-1.研究表明,Na+/K+为20:1比例施用钾肥可最大限度地降低NaCl胁迫对盛花期长春花生长造成的伤害,并显著促进其生物碱的代谢,显著提高长春花盛花期4种主要生物碱的含量. 相似文献
10.
We have previously shown that there is high Na(+)/Ca(2+) exchange (NCX) activity in bovine adrenal chromaffin cells. In this study, by monitoring the [Ca(2+)](i) change in single cells and in a population of chromaffin cells, when the reverse mode of exchanger activity has been initiated, we have shown that the NCX activity is enhanced by K(+). The K(+)-enhanced activity accounted for a significant proportion of the Na(+)-dependent Ca(2+) uptake activity in the chromaffin cells. The results support the hypothesis that both NCX and Na(+)/Ca(2+)-K(+) exchanger (NCKX) are co-present in chromaffin cells. The expression of NCKX in chromaffin cells was further confirmed using PCR and northern blotting. In addition to the plasma membrane, the exchanger activity, measured by Na(+)-dependent (45)Ca(2+) uptake, was also present in membrane isolated from the chromaffin granules enriched fraction and the mitochondria enriched fraction. The results support that both NCX and NCKX are present in bovine chromaffin cells and that the regulation of [Ca(2+)](i) is probably more efficient with the participation of NCKX. 相似文献
11.
Treatment of Friend erythroleukemia cells with several different chemical agents causes an early decrease in the 86Rb+ influx mediated by Na+/K+ adenosine triphosphatase (ATPase). These agents, which induced Friend cells to differentiate, include dimethylsulfoxide (DMSO), ouabain, hypoxanthine, and actinomycin D. The magnitude of the early decrease in 86Rb+ influx correlates with the proportion of cells in cultures of inducible Friend cell clones which later go on to synthesize hemoglobin. Compounds which do not incude differentiation in these cells, such as xanthine, exogenous hematin, and erythropoietin, do not cause a change in 86Rb+ influx. A change in the intracellular K+ ion concentration does not occur during induction by DMSO because, although there is a decrease in K+ content per cell soon after induction, there is a parallel decrease in cell volume. These results and previous observations from this laboratory are discussed in terms of the posible involvement of the Na+/K+ ATPase in Friend cell differentiation. 相似文献
12.
The plasma membrane potential (deltapsi) of procyclic and bloodstream trypomastigotes of Trypanosoma brucei was studied using the potentiometric fluorescent dye bisoxonol. Our results suggest that a proton pump plays a significant role in the regulation of deltapsi in procyclic and bloodstream forms, as evidenced by depolarization of the plasma membrane by H(+)-ATPase inhibitors (e.g. dicyclohexylcarbo-diimide, N-ethylmaleimide, diethylstilbestrol, and bafilomycin A1). In bloodstream stages the plasma membrane was significantly depolarized by ouabain only when the cells were incubated in sodium-rich buffers indicating that a sodium pump was being inhibited. In contrast, ouabain had no effect on the deltapsi of the procyclic stages in a sodium-rich buffer. However, it induced an additional significant depolarization in these stages when their plasma membrane was already partially depolarized by the H(+)-ATPase inhibitor dicyclohexylcarbo-diimide, indicating the presence of an ouabain-sensitive sodium pump whose activity is masked by the H(+)-ATPase. Unlike procyclic forms, the deltapsi of bloodstream-stage trypomastigotes was markedly sensitive to extracellular Na+ and K+ concentrations. Thus, there are significant differences between procyclic and bloodstream forms in the maintenance of the deltapsi and in their permeability to cations. 相似文献
13.
久效磷对美国红鱼鳃Na^＋／K^＋-ATP酶活性和超显微结构的影响 总被引：12，自引：1，他引：11
经不同试验浓度的久效磷(0．25、0．5、1．0和2．0mg·L^-1)处理美国红鱼4d后,分别对鱼鳃Na^+／K^+—ATP酶活性和氯细胞密度进行了测定和计数,并观察了鱼鳃组织显微结构和超微结构的变化。结果表明,低浓度久效磷(0．25mg·L^-1)处理可以诱导鱼鳃氯细胞大量增生,Na^+／K^+—ATP酶活性增强,随着试验浓度的增加,久效磷对鳃组织的损伤越来越重,Na^+／K^+—ATP酶活性逐渐降低;久效磷对鱼鳃显微结构的损伤表现为鳃小片上皮细胞水肿、脱离。鳃小片基部粘连。鳃小片上皮细胞角质化;超微结构变化主要为内质网、线粒体、微小管和核膜的水肿及部分溶解,这种损伤表现为由细胞膜到细胞核的动态过程。 相似文献
14.
Kubala M 《Proteins》2006,64(1):1-12
P-type ATPases form a large family of cation translocating ATPases. Recent progress in crystallography yielded several high-resolution structures of Ca(2+)-ATPase from sarco(endo)plasmic reticulum (SERCA) in various conformations. They could elucidate the conformational changes of the enzyme, which are necessary for the translocation of cations, or the mechanism that explains how the nucleotide binding is coupled to the cation transport. However, crystals of proteins are usually obtained only under conditions that significantly differ from the physiological ones and with ligands that are incompatible with the enzyme function, and both of these factors can inevitably influence the enzyme structure. Biochemical (such as mutagenesis, cleavage, and labeling) or spectroscopic experiments can yield only limited structural information, but this information could be considered relevant, because measurement can be performed under physiological conditions and with true ligands. However, interpretation of some biochemical or spectroscopic data could be difficult without precise knowledge of the structure. Thus, only a combination of both these approaches can extract the relevant information and identify artifacts. Briefly, there is good agreement between crystallographic and other experimental data concerning the overall shape of the molecule and the movement of cytoplasmic domains. On the contrary, the E1-AMPPCP crystallographic structure is, in details, in severe conflict with numerous spectroscopic experiments and probably does not represent the physiological state. Notably, the E1-ADP-AlF(4) structure is almost identical to the E1-AMPPCP, again suggesting that the structure is primarily determined by the crystal-growth conditions. The physiological relevance of the E2 and E2-P structures is also questionable, because the crystals were prepared in the presence of thapsigargin, which is known to be a very efficient inhibitor of SERCA. Thus, probably only crystals of E1-2Ca conformation could reflect some physiological state. Combination of biochemical, spectroscopic, and crystallographic data revealed amino acids that are responsible for the interaction with the nucleotide. High sequence homology of the P-type ATPases in the cytoplasmic domains enables prediction of the ATP-interacting amino acids also for other P-type ATPases. 相似文献
15.
Jonathan P. Velotta Stephen D. McCormick Eric T. Schultz 《Evolution; international journal of organic evolution》2015,69(10):2676-2688
Adaptation to freshwater may be expected to reduce performance in seawater because these environments represent opposing selective regimes. We tested for such a trade‐off in populations of the Alewife (Alosa pseudoharengus). Alewives are ancestrally anadromous, and multiple populations have been independently restricted to freshwater (landlocked). We conducted salinity challenge experiments, whereby juvenile Alewives from one anadromous and multiple landlocked populations were exposed to freshwater and seawater on acute and acclimation timescales. In response to acute salinity challenge trials, independently derived landlocked populations varied in the degree to which seawater tolerance has been lost. In laboratory‐acclimation experiments, landlocked Alewives exhibited improved freshwater tolerance, which was correlated with reductions in seawater tolerance and hypo‐osmotic balance, suggesting that trade‐offs in osmoregulation may be associated with local adaptation to freshwater. We detected differentiation between life‐history forms in the expression of an ion‐uptake gene (NHE3), and in gill Na+/K+‐ATPase activity. Trade‐offs in osmoregulation, therefore, may be mediated by differentiation in ion‐uptake and salt‐secreting pathways. 相似文献
16.
Larisa V. Smolyaninova Alexander A. Dergalev Konstantin Y. Kulebyakin David O. Carpenter Alexander A. Boldyrev 《Cell biochemistry and function》2013,31(1):30-35
It is known that ouabain, a selective inhibitor of Na/K‐ATPase, not only can cause the activation of signal cascades, which regulate the cell viability, but also can cause the accumulation of free radicals, which can evoke the oxidative stress. We have shown that the nanomolar concentrations of ouabain result in the temporary increase in the level of intracellular free radicals, but the millimolar concentration of ouabain induces a stable intracellular accumulation of free radicals in rat thymocytes. The increasing level of free radicals resulting from both low and high concentrations of ouabain can be attenuated by the antioxidant, carnosine. Moreover, the long‐term incubation with ouabain leads to the cell death by necrosis and apoptosis. Ouabain‐mediated apoptosis and necrosis were also abolished by carnosine. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
17.
Newton LD Kastelic JP Wong B van der Hoorn F Thundathil J 《Molecular reproduction and development》2009,76(1):109-118
The objective of this study was to determine the effects of elevated testicular temperature on the expression patterns of sperm proteins in bulls. Ejaculates were collected from sexually mature Holstein bulls (n = 6) twice weekly for 10 weeks. Testicular temperature was elevated in all bulls by scrotal insulation for 72 consecutive hours during Week 2. Triton X-100 extracts of sperm proteins were prepared and subjected to SDS-PAGE. Sperm proteins in the 110 kDa range decreased from pre-thermal insult to Day 28 (start of thermal insult = Day 0), concurrent with decreases in sperm concentration, motility, and morphology, and subsequently increased, approaching pre-thermal insult values by Day 40. Based on mass spectrometry, this band was comprised of angiotensin converting enzyme (ACE), Hexokinase-1, and the alpha-4 subunit of Na(+)/K(+)ATPase. Changes in the expression patterns of these proteins were confirmed by immunoblotting, including the use of a custom antibody against the alpha-4 subunit of Na(+)/K(+)ATPase (testis-specific isoform). Furthermore, a 25 kDa sperm protein (identified as tissue inhibitor of metalloproteinase-2; TIMP-2), had a low expression level in pre-thermal insult samples, increased to Day 28 of post-thermal insult, and subsequently decreased to the pre-thermal insult level by the end of the experimental period. In conclusion, we identified proteins that may serve as molecular markers of impaired sperm function due to elevated testicular temperature, with important implications for fertility predictions. To our knowledge, this is the first report of the identification of a testis-specific isoform of Na(+)/K(+)ATPase in bovine sperm. 相似文献
18.
Michael V. Martinov Victor M. Vitvitsky Fazoil I. Ataullakhanov 《Biophysical chemistry》1999,80(3):101-215
A mathematical model describing the possible role of Ca2+-dependent K+ channels and adenylate metabolism in volume stabilization of human erythrocytes was developed. The model predicts that the red blood cell volume can be stabilized either dynamically or stationary over a broad range of cell membrane permeabilities to cations. The dynamic stabilization results from the operation of Ca2+-dependent potassium channels. The erythrocyte volume changes less than 10% if the membrane permeability changes abruptly to a value in the range from half to sevenfold higher than the normal one. The stationary stabilization is achieved via controlling the adenylate metabolism. The stationary value of cell volume changes less than 10% when the membrane permeability varies from half the normal value to 15-fold higher than the normal value. 相似文献
19.
Larisa V. Karpova Elena R. Bulygina Alexander A. Boldyrev 《Cell biochemistry and function》2010,28(2):135-141
Inhibition of rat neuronal Na+/K+‐ATPase α3 isoform at low (100 nM) ouabain concentration led to activation of MAP kinase cascade via PKC and PIP3 kinase. In contrast to ouabain‐sensitive α3 isoform of Na+/K+‐ATPase, an ouabain‐resistant α1 isoform (inhibition with 1 mM of ouabain) of Na+/K+‐ATPase regulates MAP kinase via Src kinase dependent reactions. Using of Annexin V‐FITC apoptotic test to determine the cells with early apoptotic features allows to conclude that α3 isoform stimulates and α1 suppresses apoptotic process in cerebellum neurons. These data are the first demonstration showing participation of ouabain‐resistant (α1) and ouabain‐sensitive (α3) Na+/K+‐ATPase isoforms in diverse signaling pathways in neuronal cells. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献