Turbulent mixing, in particular on a small scale, aff ects the growth of microalgae by changing diff usive sublayers and regulating nutrient fluxes of cells. We tested the nutrient flux hypothesis by evaluating the ce...Turbulent mixing, in particular on a small scale, aff ects the growth of microalgae by changing diff usive sublayers and regulating nutrient fluxes of cells. We tested the nutrient flux hypothesis by evaluating the cellular stoichiometry and phosphorus storage of microalgae under dif ferent turbulent mixing conditions. A phanizomenon flos-aquae were cultivated in dif ferent stirring batch reactors with turbulent dissipation rates ranging from 0.001 51 m2/s 3 to 0.050 58 m 2/s 3, the latter being the highest range observed in natural aquatic systems. Samples were taken in the exponential growth phase and compared with samples taken when the reactor was completely stagnant. Results indicate that, within a certain range, turbulent mixing stimulates the growth of A. flos-aquae. An inhibitory ef fect on growth rate was observed at the higher range. Photosynthesis activity, in terms of maximum ef fective quantum yield of PSII(the ratio of F v/F m) and cellular chlorophyll a, did not change significantly in response to turbulence. However, Chl a/C mass ratio and C/N molar ratio, showed a unimodal response under a gradient of turbulent mixing, similar to growth rate. Moreover, we found that increases in turbulent mixing might stimulate respiration rates, which might lead to the use of polyphosphate for the synthesis of cellular constituents. More research is required to test and verify the hypothesis that turbulent mixing changes the dif fusive sublayer, regulating the nutrient flux of cells.展开更多
Arachidonic acid cytochrome P-450 （CYP） hydroxylase 4A isoforms, including 4A1, 4A2, 4A3 and 4A8 in the rat kidney, catalyze arachidonic acid to produce 19/20-Hydroxyeicosatetraenoic acids （20-HETE）, a biologicall...Arachidonic acid cytochrome P-450 （CYP） hydroxylase 4A isoforms, including 4A1, 4A2, 4A3 and 4A8 in the rat kidney, catalyze arachidonic acid to produce 19/20-Hydroxyeicosatetraenoic acids （20-HETE）, a biologically active metabolite, which plays an important role in the regulation of blood pressure. However, controversial results have been reported regarding the exact role of 20-HETE on blood pressure. In the present study, we used recombinant adenoassociated viral vector （rAAV） to deliver CYP 4A1 cDNA and antisense 4A1 cDNA into Sprague-Dawley （SD） rats and spontaneously hypertensive rats （SHR）, respectively, to investigate the effects of long-term modifications of blood pressure and the potential for gene therapy of hyperténsion. The mean systolic pressure increased by 14.2±2.5 mm Hg in rAAV.4A 1-treated SD rats and decreased by 13.7±2.2 mm Hg in rAAV.anti4A l-treated SHR rats 5 weeks after the injection compared with controls and these changes in blood pressure were maintained until the experiments ended at 24 weeks. In 4A1 treated animals CYP4A was overexpressed in various tissues, but preferentially in the kidney at both mRNA and protein levels. In anti-4Al-treated SHR, CYP4A mRNA in various tissues was probed, especially in kidneys, but 4A l protein expression was almost completely inhibited. These results suggest that arachidonic acid CYP hydroxylases contribute not only to the maintenance of normal blood pressure but also to the development of hypertension. rAAV-mediated anti4A administration strategy has the potential to be used as targeted gene therapy in human hypertension by blocking expression of CYP 4A in kidneys.展开更多
AIM: To assess the anti-inflammatory effect of the probiotic Bifidobacterium lactis (B. lactis) in an adoptive transfer model of colitis. METHODS: Donor and recipient mice received either B. lactis or bacterial cultur...AIM: To assess the anti-inflammatory effect of the probiotic Bifidobacterium lactis (B. lactis) in an adoptive transfer model of colitis. METHODS: Donor and recipient mice received either B. lactis or bacterial culture medium as control (deMan Rogosa Sharpe) in drinking water for one week prior to transfer of a mix of naive and regulatory T cells until sacrifice. RESULTS: All recipient mice developed signs of colonic inflammation, but a significant reduction of weight loss was observed in B. lactis-fed recipient mice compared to control mice. Moreover, a trend toward a diminution of mucosal thickness and attenuated epithelial damage was revealed. Colonic expression of pro-inflammatory and T cell markers was significantly reduced in B. lactis-fed recipient mice compared to controls. Concomitantly, forkhead box protein 3, a marker of regulatory T cells, was significantly up-regulated by B. lactis. CONCLUSION: Daily oral administration of B. lactis was able to reduce inflammatory and T cells mediators and to promote regulatory T cells specific markers in a mouse model of colitis.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.51309220,51679226)the National Key SandT Project on Water Pollution Control and Treatment(Nos.2014ZX07104-006,2015ZX07103-007)the Western Action Program funded by the Chinese Academy of Sciences(No.KZCX2-XB3-14)
文摘Turbulent mixing, in particular on a small scale, aff ects the growth of microalgae by changing diff usive sublayers and regulating nutrient fluxes of cells. We tested the nutrient flux hypothesis by evaluating the cellular stoichiometry and phosphorus storage of microalgae under dif ferent turbulent mixing conditions. A phanizomenon flos-aquae were cultivated in dif ferent stirring batch reactors with turbulent dissipation rates ranging from 0.001 51 m2/s 3 to 0.050 58 m 2/s 3, the latter being the highest range observed in natural aquatic systems. Samples were taken in the exponential growth phase and compared with samples taken when the reactor was completely stagnant. Results indicate that, within a certain range, turbulent mixing stimulates the growth of A. flos-aquae. An inhibitory ef fect on growth rate was observed at the higher range. Photosynthesis activity, in terms of maximum ef fective quantum yield of PSII(the ratio of F v/F m) and cellular chlorophyll a, did not change significantly in response to turbulence. However, Chl a/C mass ratio and C/N molar ratio, showed a unimodal response under a gradient of turbulent mixing, similar to growth rate. Moreover, we found that increases in turbulent mixing might stimulate respiration rates, which might lead to the use of polyphosphate for the synthesis of cellular constituents. More research is required to test and verify the hypothesis that turbulent mixing changes the dif fusive sublayer, regulating the nutrient flux of cells.
基金This project Was supported by the National Natural Science Foundation of China(NSFC,No.39870307)National Basic Research Program of China(973 Program,No.G2000056901)KC was the recipient of an Fonds de la recherche en sante du Quebec(FRSQ,Quebec-Canada)-NSFC(China exchange grant).
文摘Arachidonic acid cytochrome P-450 （CYP） hydroxylase 4A isoforms, including 4A1, 4A2, 4A3 and 4A8 in the rat kidney, catalyze arachidonic acid to produce 19/20-Hydroxyeicosatetraenoic acids （20-HETE）, a biologically active metabolite, which plays an important role in the regulation of blood pressure. However, controversial results have been reported regarding the exact role of 20-HETE on blood pressure. In the present study, we used recombinant adenoassociated viral vector （rAAV） to deliver CYP 4A1 cDNA and antisense 4A1 cDNA into Sprague-Dawley （SD） rats and spontaneously hypertensive rats （SHR）, respectively, to investigate the effects of long-term modifications of blood pressure and the potential for gene therapy of hyperténsion. The mean systolic pressure increased by 14.2±2.5 mm Hg in rAAV.4A 1-treated SD rats and decreased by 13.7±2.2 mm Hg in rAAV.anti4A l-treated SHR rats 5 weeks after the injection compared with controls and these changes in blood pressure were maintained until the experiments ended at 24 weeks. In 4A1 treated animals CYP4A was overexpressed in various tissues, but preferentially in the kidney at both mRNA and protein levels. In anti-4Al-treated SHR, CYP4A mRNA in various tissues was probed, especially in kidneys, but 4A l protein expression was almost completely inhibited. These results suggest that arachidonic acid CYP hydroxylases contribute not only to the maintenance of normal blood pressure but also to the development of hypertension. rAAV-mediated anti4A administration strategy has the potential to be used as targeted gene therapy in human hypertension by blocking expression of CYP 4A in kidneys.
文摘AIM: To assess the anti-inflammatory effect of the probiotic Bifidobacterium lactis (B. lactis) in an adoptive transfer model of colitis. METHODS: Donor and recipient mice received either B. lactis or bacterial culture medium as control (deMan Rogosa Sharpe) in drinking water for one week prior to transfer of a mix of naive and regulatory T cells until sacrifice. RESULTS: All recipient mice developed signs of colonic inflammation, but a significant reduction of weight loss was observed in B. lactis-fed recipient mice compared to control mice. Moreover, a trend toward a diminution of mucosal thickness and attenuated epithelial damage was revealed. Colonic expression of pro-inflammatory and T cell markers was significantly reduced in B. lactis-fed recipient mice compared to controls. Concomitantly, forkhead box protein 3, a marker of regulatory T cells, was significantly up-regulated by B. lactis. CONCLUSION: Daily oral administration of B. lactis was able to reduce inflammatory and T cells mediators and to promote regulatory T cells specific markers in a mouse model of colitis.
