Auxin is unique among plant hormones in that its function requires polarized transport across plant cells.A chemiosmotic model was proposed to explain how polar auxin transport is derived by the H^(+)gradient across t...Auxin is unique among plant hormones in that its function requires polarized transport across plant cells.A chemiosmotic model was proposed to explain how polar auxin transport is derived by the H^(+)gradient across the plasma membrane(PM)established by PM H^(+)-adenosine triphosphatases(ATPases).However,a classical genetic approach by mutations in PM H^(+)-ATPase members did not result in the ablation of polar auxin distribution,possibly due to functional redundancy in this gene family.To confirm the crucial role of PM H^(+)-ATPases in the polar auxin transport model,we employed a chemical genetic approach.Through a chemical screen,we identified protonstatin-1(PS-1),a selective small-molecule inhibitor of PM H^(+)-ATPase activity that inhibits auxin transport.Assays with transgenic plants and yeast strains showed that the activity of PM H^(+)-ATPases affects auxin uptake as well as acropetal and basipetal polar auxin transport.We propose that PS-1 can be used as a tool to interrogate the function of PM H^(+)-ATPases.Our results support the chemiosmotic model in which PM H^(+)-ATPase itself plays a fundamental role in polar auxin transport.展开更多
AIM： To investigate the dynamic functional and ultrastructural changes of gastric parietal cells induced by water immersion-restraint stress （WRS） in rats.METHODS： WRS model of Sprague-Dawley （SD） rats was estab...AIM： To investigate the dynamic functional and ultrastructural changes of gastric parietal cells induced by water immersion-restraint stress （WRS） in rats.METHODS： WRS model of Sprague-Dawley （SD） rats was established. Fifty-six male SD rats were randomly divided into control group, stress group and post-stress group. The stress group was divided into 1, 2 and 4 h stress subgroups. The post-stress group was divided into 24, 48 and 72 h subgroups. The pH value of gastric juice, ulcer index （UI） of gastric mucosa and H^＋, K^＋- ATPase activity of gastric parietal cells were measured. Ultrastructural change of parietal cells was observed under transmission electron microscope （TEM）.RESULTS： The pH value of gastric juice decreased time-dependently in stress group and increased in post-stress group. The H^＋, K^＋-ATPase activity of gastric parietal cells and the UI of gastric mucosa increased time-dependently in stress group and decreased in poststress group. Compared to control group, the pH value decreased remarkably （P = 0.0001）, the UI and H^＋, K^＋- ATPase activity increased significantly （P = 0.0001, P = 0.0174） in 4 h stress subgroup. UI was positively related with stress time （r = 0.9876, P 〈 0.01） but negatively with pH value （r = -0.8724, P 〈 0.05）. The parietal cells became active in stress group, especially in 4 h stress subgroup, in which plenty of intracellular canalicular and mitochondria were observed under TEM. In post-stress group, the parietal cells recovered to resting state.CONCOUSION： The acid secretion of parietal cells is consistent with their ultrastructural changes during the development and healing of stress ulcer induced by WRS and the degree of gastric mucosal lesions, suggesting gastric acid play an important role in the development of stress ulcer and is closely related with the recovery of gastric mucosal lesions induced by WRS.展开更多
AIM To investigate the effects of nesfatin-1 on gastric function in obese rats. METHODS The obese rat model was induced by a high-fat diet. The gastric emptying rate and gastric acid secretory capacity of the rats wer...AIM To investigate the effects of nesfatin-1 on gastric function in obese rats. METHODS The obese rat model was induced by a high-fat diet. The gastric emptying rate and gastric acid secretory capacity of the rats were determined after treatment with different drug concentrations of nesfatin-1 and administration routes. Based on this, the expression of H+/K+-ATPase was measured using RT-PCR and western blot to preliminarily explore the mechanism of gastric acid secretion changes. RESULTS Body weight, body length, and Lee's index of the rats significantly increased in the high-fat dietinduced obese rat model. Two hours after lateral intracerebroventricular injection of nesfatin-1, the gastric emptying rate and gastric acid secretory capacity of rats decreased. Four hours after injection, both were restored to normal levels. In addition, the expression of H+/K+-ATPase decreased and moved in line with changes in gastric acid secretory capacity. Thisin vivo experiment revealed that intracerebroventricular injection of nesfatin-1, rather than intravenous injection, could suppress gastric function in obese rats. Moreover, its effect on the gastric emptying and gastric acid secretory capacity of rats is dose-dependent within a certain period of time.CONCLUSION Through this research, we provide a theoretical basis for further studies on nesfatin-1, a potential antiobesity drug.展开更多
AIM: To investigate H+, K+-ATPase inhibition, anti-H pylori , antioxidant, and the in vivo antiulcer potential of a pectic polysaccharide from Swallow root (Decalepis hamiltonii; SRPP). METHODS: SRPP, with known sugar...AIM: To investigate H+, K+-ATPase inhibition, anti-H pylori , antioxidant, and the in vivo antiulcer potential of a pectic polysaccharide from Swallow root (Decalepis hamiltonii; SRPP). METHODS: SRPP, with known sugar composition [rhamnose: arabinose: xylose: galactose in the ratio of 16:50:2:32 (w/w), with 141 mg/g of uronic acid] was examined for anti-ulcer potency in vivo against swim/ ethanol stress-induction in animal models. Ulcer index, antioxidant/antioxidant enzymes, H+, K+-ATPase and gastric mucin levels were determined to assess the anti- ulcer potency. Anti-H pylori activity was also determined by viable colony count and electron microscopic studies. RESULTS: SRPP, containing phenolics at 0.12 g GAE/g, prevented stress-induced gastric ulcers in animal models by 80%-85%. Down regulation of gastric mucin 2-3 fold, antioxidant/antioxidant enzymes and upregulation of 3 fold of H+, K+-ATPase in ulcerous animals were normalized upon treatment with SRPP. Histopathological analysis revealed protection to the disrupted gastric mucosal layer and epithelial glands. SRPP also inhibited H+, K+-ATPase in vitro, at an IC50 of 77 μg/mL as opposed to that of 19.3 μg/mL of Lansoprazole and H pylori growth at Minimum Inhibitory Concentration (MIC) of 150 μg/mL. In addition, free radical scavenging (IC50-40 μg/mL) and reducing power (3200 U/g) activities were also observed. CONCLUSION: SRPP, with defined sugar composition and phenolics, exhibited multi-potent free radical scavenging, antioxidant, anti-H pylori, inhibition of H+, K+-ATPase and gastric mucosal protective activities. In addition, SRPP is non-toxic as opposed to other known anti-ulcer drugs, and therefore may be employed as a potential alternative for ulcer management.展开更多
基金supported by the National Key Research and Development Program of China (2017YFA0505200 to X.L.)the National Natural Science Foundation of China (21625201, 219611 42010, 91853202 to X.L.+1 种基金32070301, 31872659 to Y.Y.)the Beijing Outstanding Young Scientist Program (BJJWZYJH01201910001001 to X.L.)
文摘Auxin is unique among plant hormones in that its function requires polarized transport across plant cells.A chemiosmotic model was proposed to explain how polar auxin transport is derived by the H^(+)gradient across the plasma membrane(PM)established by PM H^(+)-adenosine triphosphatases(ATPases).However,a classical genetic approach by mutations in PM H^(+)-ATPase members did not result in the ablation of polar auxin distribution,possibly due to functional redundancy in this gene family.To confirm the crucial role of PM H^(+)-ATPases in the polar auxin transport model,we employed a chemical genetic approach.Through a chemical screen,we identified protonstatin-1(PS-1),a selective small-molecule inhibitor of PM H^(+)-ATPase activity that inhibits auxin transport.Assays with transgenic plants and yeast strains showed that the activity of PM H^(+)-ATPases affects auxin uptake as well as acropetal and basipetal polar auxin transport.We propose that PS-1 can be used as a tool to interrogate the function of PM H^(+)-ATPases.Our results support the chemiosmotic model in which PM H^(+)-ATPase itself plays a fundamental role in polar auxin transport.
基金Supported by the Key Project of Military Medicine during the 10th five-year Plan period, PLA, China, No. 01Z059
文摘AIM： To investigate the dynamic functional and ultrastructural changes of gastric parietal cells induced by water immersion-restraint stress （WRS） in rats.METHODS： WRS model of Sprague-Dawley （SD） rats was established. Fifty-six male SD rats were randomly divided into control group, stress group and post-stress group. The stress group was divided into 1, 2 and 4 h stress subgroups. The post-stress group was divided into 24, 48 and 72 h subgroups. The pH value of gastric juice, ulcer index （UI） of gastric mucosa and H^＋, K^＋- ATPase activity of gastric parietal cells were measured. Ultrastructural change of parietal cells was observed under transmission electron microscope （TEM）.RESULTS： The pH value of gastric juice decreased time-dependently in stress group and increased in post-stress group. The H^＋, K^＋-ATPase activity of gastric parietal cells and the UI of gastric mucosa increased time-dependently in stress group and decreased in poststress group. Compared to control group, the pH value decreased remarkably （P = 0.0001）, the UI and H^＋, K^＋- ATPase activity increased significantly （P = 0.0001, P = 0.0174） in 4 h stress subgroup. UI was positively related with stress time （r = 0.9876, P 〈 0.01） but negatively with pH value （r = -0.8724, P 〈 0.05）. The parietal cells became active in stress group, especially in 4 h stress subgroup, in which plenty of intracellular canalicular and mitochondria were observed under TEM. In post-stress group, the parietal cells recovered to resting state.CONCOUSION： The acid secretion of parietal cells is consistent with their ultrastructural changes during the development and healing of stress ulcer induced by WRS and the degree of gastric mucosal lesions, suggesting gastric acid play an important role in the development of stress ulcer and is closely related with the recovery of gastric mucosal lesions induced by WRS.
基金Supported by Cangzhou City Science and Technology Plan Projects,No.151302138
文摘AIM To investigate the effects of nesfatin-1 on gastric function in obese rats. METHODS The obese rat model was induced by a high-fat diet. The gastric emptying rate and gastric acid secretory capacity of the rats were determined after treatment with different drug concentrations of nesfatin-1 and administration routes. Based on this, the expression of H+/K+-ATPase was measured using RT-PCR and western blot to preliminarily explore the mechanism of gastric acid secretion changes. RESULTS Body weight, body length, and Lee's index of the rats significantly increased in the high-fat dietinduced obese rat model. Two hours after lateral intracerebroventricular injection of nesfatin-1, the gastric emptying rate and gastric acid secretory capacity of rats decreased. Four hours after injection, both were restored to normal levels. In addition, the expression of H+/K+-ATPase decreased and moved in line with changes in gastric acid secretory capacity. Thisin vivo experiment revealed that intracerebroventricular injection of nesfatin-1, rather than intravenous injection, could suppress gastric function in obese rats. Moreover, its effect on the gastric emptying and gastric acid secretory capacity of rats is dose-dependent within a certain period of time.CONCLUSION Through this research, we provide a theoretical basis for further studies on nesfatin-1, a potential antiobesity drug.
文摘AIM: To investigate H+, K+-ATPase inhibition, anti-H pylori , antioxidant, and the in vivo antiulcer potential of a pectic polysaccharide from Swallow root (Decalepis hamiltonii; SRPP). METHODS: SRPP, with known sugar composition [rhamnose: arabinose: xylose: galactose in the ratio of 16:50:2:32 (w/w), with 141 mg/g of uronic acid] was examined for anti-ulcer potency in vivo against swim/ ethanol stress-induction in animal models. Ulcer index, antioxidant/antioxidant enzymes, H+, K+-ATPase and gastric mucin levels were determined to assess the anti- ulcer potency. Anti-H pylori activity was also determined by viable colony count and electron microscopic studies. RESULTS: SRPP, containing phenolics at 0.12 g GAE/g, prevented stress-induced gastric ulcers in animal models by 80%-85%. Down regulation of gastric mucin 2-3 fold, antioxidant/antioxidant enzymes and upregulation of 3 fold of H+, K+-ATPase in ulcerous animals were normalized upon treatment with SRPP. Histopathological analysis revealed protection to the disrupted gastric mucosal layer and epithelial glands. SRPP also inhibited H+, K+-ATPase in vitro, at an IC50 of 77 μg/mL as opposed to that of 19.3 μg/mL of Lansoprazole and H pylori growth at Minimum Inhibitory Concentration (MIC) of 150 μg/mL. In addition, free radical scavenging (IC50-40 μg/mL) and reducing power (3200 U/g) activities were also observed. CONCLUSION: SRPP, with defined sugar composition and phenolics, exhibited multi-potent free radical scavenging, antioxidant, anti-H pylori, inhibition of H+, K+-ATPase and gastric mucosal protective activities. In addition, SRPP is non-toxic as opposed to other known anti-ulcer drugs, and therefore may be employed as a potential alternative for ulcer management.
