In order to learn the ways and possible utilization mechanisms of dissolved inorganic carbon (DIC) in marine phytoplankton species under carbon-replete or -limited conditions, the activity of extracellular carbonic an...In order to learn the ways and possible utilization mechanisms of dissolved inorganic carbon (DIC) in marine phytoplankton species under carbon-replete or -limited conditions, the activity of extracellular carbonic anhydrase (CA) was assayed in different pH, CO 2 and DIC concentrations. Extracellular CA in Amphidinium carterae and Prorocentrum minimum was detected under carbon-replete conditions, while in Melosira sp., Phaeodactylum tricornutum, Skeletonema costatum, Thalassiosira rotula, Emiliania huxleyi and Pleurochrysis carterae, CA activity was assayed under conditions of carbon limitation. No CA activity was found even under carbon-limited conditions in Chaetoceros compressus, Glenodinium foliaceum, Coccolithus pelagicus, Gephrocapsa oceanica and Heterosigma akashiwo. In species without extracellular CA activity, the direct HCO - 3 uptake was investigated using a pH drift technique and the anion exchange inhibitor 4′4′-diisothiocyanatostilbene-2,2-disulfonic acid (DIDS) in a closed system. The result showed that direct HCO - 3 transport might occur by an anion exchange mechanism in species Coc. pelagicus and G. oceanica. Of the 13 species investigated, only H. akashiwo did not have the potential for direct uptake or extracellular CA-catalyzed HCO - 3 utilization.展开更多
Carbonic anhydrases (CAs) catalyse the hydration of C02 to bicarbonate at physiological pH. This chemical interconversion is crucial since HCO3- is the substrate for several biosynthetic reactions. This review is focu...Carbonic anhydrases (CAs) catalyse the hydration of C02 to bicarbonate at physiological pH. This chemical interconversion is crucial since HCO3- is the substrate for several biosynthetic reactions. This review is focused on the distribution and role of CA isoenzymes in both normal and pathological gastrointestinal (GI) tract tissues. It has been known for many years that CAs are widely present in the GI tract and play important roles in several physiological functions such as production of saliva, gastric acid, bile, and pancreatic juice as well as in absorption of salt and water in intestine. New information suggests that these enzymes participate in several processes that were not envisioned earlier. Especially, the recent reports on plasma membrane-bound isoenzymes IX and XII have raised considerable interest since they were reported to participate in cancer invasion and spread. They are induced by tumour hypoxia and may also play a role in von Hippel-Lindau (VHL)-mediated carcinogenesis.展开更多
Utilization of carbon dioxide(CO_(2))has become a crucial and anticipated solution to address environmental and ecological issues.Enzymes such as carbonic anhydrase(CA)can efficiently convert CO_(2) into various platf...Utilization of carbon dioxide(CO_(2))has become a crucial and anticipated solution to address environmental and ecological issues.Enzymes such as carbonic anhydrase(CA)can efficiently convert CO_(2) into various platform chemicals under ambient conditions,which offers a promising way for CO_(2) utilization.Herein,we constructed a Pickering interfacial biocatalytic system(PIBS)stabilized by CA‐embedded MOFs(ZIF‐8 and ZIF‐L)for CO_(2) mineralization.Through structure engineering of MOFs and incorporation of Pickering emulsion,the internal and external diffusion processes of CO_(2) during the enzymatic mineralization were greatly intensified.When CO_(2) was ventilated at a flow rate of 50 mL min^(–1) for 1 h,the pH value of PIBS dropped from~8.00 to~6.50,while the average pH value of free system only dropped to~7.15,indicating that the initial reaction rate of CO_(2) mineralization of PIBS is nearly twice that of the free system.After the 8^(th) cycle reaction,PIBS can still produce more than 9.8 mg of CaCO_(3) in 5 min,realizing efficient and continuous mineralization of CO_(2).展开更多
Thirty-four sampling sites for surface water and twenty-seven sampling sites for ground water in areas of different land use were selected in the Wujiang River Basin, upstream section in Guizhou Province, China. Carbo...Thirty-four sampling sites for surface water and twenty-seven sampling sites for ground water in areas of different land use were selected in the Wujiang River Basin, upstream section in Guizhou Province, China. Carbonic anhydrase （CA） activity in surface and ground water was analyzed and compared. The results show that CA activity was detected in all surface and ground water samples. In general, average CA activity in surface and ground water was highest from samples in arbor lands, followed by shrub lands, shrub and grass lands, agricultural lands, and residential areas. The average CA activity in ground water from arbor lands, shrub lands, and shrub and grass lands was higher than that in surface water. Water CA activity was positively correlated with HCO3- concentration in surface water and ground water. These results imply that the contribution of CA in water to the karst carbon sink potential of river basins warrants further extensive and in-depth research.展开更多
Objective To demonstrate the molecular expression of carbonic anhydrase Ⅳ (CA Ⅳ) in rabbit corneal endothelium.Methods Reverse transcriptase polymerase chain reaction (RT-PCR) was performed using cultured and fres...Objective To demonstrate the molecular expression of carbonic anhydrase Ⅳ (CA Ⅳ) in rabbit corneal endothelium.Methods Reverse transcriptase polymerase chain reaction (RT-PCR) was performed using cultured and fresh rabbit corneal endothelial total RNA and specific primers for CA Ⅳ. The RT-PCR product was subcloned and sequenced. Immunoblotting and indirect immunofluorescence staining were performed to detect protein expression and distribution of CA Ⅳ using fresh and cultured rabbit corneal endothelium and rat anti-CA Ⅳ polyclonal antibody. Results RT-PCR screening gave positive bands at the predicted size for CA Ⅳ from fresh and cultured rabbit corneal endothelium. Sequencing further confirmed the identity of CA Ⅳ in corneal endothelium. Immunoblotting analysis showed a single band at 52 kDa for freshly isolated and cultured endothelial cells. Indirect immunofluorescence staining revealed an apparent positive staining in cultured endothelial cells.Conclusion Carbonic anhydrase Ⅳ is expressed in rabbit corneal endothelium, which could contribute to the transendothelial HCO 3 - flux that is necessary to maintain corneal hydration and transparency.展开更多
We investigated the differences in the gene expression of carbonic anhydrase （CA） and cysteine synthase （CysM） between two weathering conditions, with either soluble potassium or insoluble potassium. We cultured a...We investigated the differences in the gene expression of carbonic anhydrase （CA） and cysteine synthase （CysM） between two weathering conditions, with either soluble potassium or insoluble potassium. We cultured a strain of A. niger by adopting a variant Czapek medium （using NazHPO4 as a substitute for KzHPO4） in two groups, Group A （containing silicate minerals bearing potassium but without KC1） and Group B （with KCI） . We extracted the mRNAs of CA and CysM from these two groups and performed real-time quantitative polymerase chain reactions （RT-qPCR）. We constructed relative standard curves by using glyceraldehyde-3-phosphate dehydrogenase （GAPDH） as the reference to confirm a consistent amplification effi- ciency of the target genes （CA and CysM） and the reference gene and quantified the gene expression of the targets in a relative manner. Our results showed that CA and CysM in Group A were upregulated for 1.7 times and 11.7 times, respectively, com- pared with those in Group B. Furthermore, we also analyzed some metabolic pathways and functions of the A. niger-induced weathering of potassium-bearing minerals, which involved the synthesizing of these two enzymes. Thus our work provides materials for further study of the roles of A. niger in the metabolic regulation during the weathering process of potassi- um-beating minerals.展开更多
Pseudobranch function has long interested scientists, but its role has yet to be elucidated. Several studies have suggested that pseudobranchs serve respiratory, osmoregulatory, and sensory functions. This work invest...Pseudobranch function has long interested scientists, but its role has yet to be elucidated. Several studies have suggested that pseudobranchs serve respiratory, osmoregulatory, and sensory functions. This work investigated the immunolocalization of pseudobranch carbonic anhydrase （CA） in the teleost fish species rainbow trout （Oncor- hynchus mykiss） to clarify its physiological function. CA was purified from rainbow trout gills O. mykiss and specific antibodies were raised. Immunoblotting between tissue homogenates of pseudobrench and gill CA antibodies showed specific immunostaining with only one band corresponding to CA in the pseudobranch homogenate. Results of im- munohistochemical technique revealed that CA was distributed within pseudobranch cells and more precisely in the apical parts （anti-vascular） of cells. The basal （vascular） parts of cells, tubular system, blood capillaries, and pillar cells were not immunostained. Immunocytochemistry confirmed these results and showed that some CA enzyme was cytoplasmic and the remainder was linked to membranous structures. The results also showed that the lacunar tissue tayers did not display immunoperoxidase activity. Our results indicated that pseudobranch CA may have a function related to the extracellular medium wherein CA intervenes with the mechanism of stimulation of afferent nerve fibers.展开更多
文摘In order to learn the ways and possible utilization mechanisms of dissolved inorganic carbon (DIC) in marine phytoplankton species under carbon-replete or -limited conditions, the activity of extracellular carbonic anhydrase (CA) was assayed in different pH, CO 2 and DIC concentrations. Extracellular CA in Amphidinium carterae and Prorocentrum minimum was detected under carbon-replete conditions, while in Melosira sp., Phaeodactylum tricornutum, Skeletonema costatum, Thalassiosira rotula, Emiliania huxleyi and Pleurochrysis carterae, CA activity was assayed under conditions of carbon limitation. No CA activity was found even under carbon-limited conditions in Chaetoceros compressus, Glenodinium foliaceum, Coccolithus pelagicus, Gephrocapsa oceanica and Heterosigma akashiwo. In species without extracellular CA activity, the direct HCO - 3 uptake was investigated using a pH drift technique and the anion exchange inhibitor 4′4′-diisothiocyanatostilbene-2,2-disulfonic acid (DIDS) in a closed system. The result showed that direct HCO - 3 transport might occur by an anion exchange mechanism in species Coc. pelagicus and G. oceanica. Of the 13 species investigated, only H. akashiwo did not have the potential for direct uptake or extracellular CA-catalyzed HCO - 3 utilization.
基金Supported by the Grants from Sigrid Juselius Foundation, The Academy of Finland (SP), Finnish Cultural Foundation and Finnish Dental Society UK)
文摘Carbonic anhydrases (CAs) catalyse the hydration of C02 to bicarbonate at physiological pH. This chemical interconversion is crucial since HCO3- is the substrate for several biosynthetic reactions. This review is focused on the distribution and role of CA isoenzymes in both normal and pathological gastrointestinal (GI) tract tissues. It has been known for many years that CAs are widely present in the GI tract and play important roles in several physiological functions such as production of saliva, gastric acid, bile, and pancreatic juice as well as in absorption of salt and water in intestine. New information suggests that these enzymes participate in several processes that were not envisioned earlier. Especially, the recent reports on plasma membrane-bound isoenzymes IX and XII have raised considerable interest since they were reported to participate in cancer invasion and spread. They are induced by tumour hypoxia and may also play a role in von Hippel-Lindau (VHL)-mediated carcinogenesis.
文摘Utilization of carbon dioxide(CO_(2))has become a crucial and anticipated solution to address environmental and ecological issues.Enzymes such as carbonic anhydrase(CA)can efficiently convert CO_(2) into various platform chemicals under ambient conditions,which offers a promising way for CO_(2) utilization.Herein,we constructed a Pickering interfacial biocatalytic system(PIBS)stabilized by CA‐embedded MOFs(ZIF‐8 and ZIF‐L)for CO_(2) mineralization.Through structure engineering of MOFs and incorporation of Pickering emulsion,the internal and external diffusion processes of CO_(2) during the enzymatic mineralization were greatly intensified.When CO_(2) was ventilated at a flow rate of 50 mL min^(–1) for 1 h,the pH value of PIBS dropped from~8.00 to~6.50,while the average pH value of free system only dropped to~7.15,indicating that the initial reaction rate of CO_(2) mineralization of PIBS is nearly twice that of the free system.After the 8^(th) cycle reaction,PIBS can still produce more than 9.8 mg of CaCO_(3) in 5 min,realizing efficient and continuous mineralization of CO_(2).
基金Sub-project of Geological Survey Work Item of China Geological Survey Bureau(Grant No.12120113005200)the Fundamental Research Funds for the Central Universities(Grant No.2015QN102)
文摘Thirty-four sampling sites for surface water and twenty-seven sampling sites for ground water in areas of different land use were selected in the Wujiang River Basin, upstream section in Guizhou Province, China. Carbonic anhydrase （CA） activity in surface and ground water was analyzed and compared. The results show that CA activity was detected in all surface and ground water samples. In general, average CA activity in surface and ground water was highest from samples in arbor lands, followed by shrub lands, shrub and grass lands, agricultural lands, and residential areas. The average CA activity in ground water from arbor lands, shrub lands, and shrub and grass lands was higher than that in surface water. Water CA activity was positively correlated with HCO3- concentration in surface water and ground water. These results imply that the contribution of CA in water to the karst carbon sink potential of river basins warrants further extensive and in-depth research.
基金ThisstudywaspartiallysupportedbythegrantfromtheChineseMedicalScienceFoundationofShandong (No 990 3 2 )
文摘Objective To demonstrate the molecular expression of carbonic anhydrase Ⅳ (CA Ⅳ) in rabbit corneal endothelium.Methods Reverse transcriptase polymerase chain reaction (RT-PCR) was performed using cultured and fresh rabbit corneal endothelial total RNA and specific primers for CA Ⅳ. The RT-PCR product was subcloned and sequenced. Immunoblotting and indirect immunofluorescence staining were performed to detect protein expression and distribution of CA Ⅳ using fresh and cultured rabbit corneal endothelium and rat anti-CA Ⅳ polyclonal antibody. Results RT-PCR screening gave positive bands at the predicted size for CA Ⅳ from fresh and cultured rabbit corneal endothelium. Sequencing further confirmed the identity of CA Ⅳ in corneal endothelium. Immunoblotting analysis showed a single band at 52 kDa for freshly isolated and cultured endothelial cells. Indirect immunofluorescence staining revealed an apparent positive staining in cultured endothelial cells.Conclusion Carbonic anhydrase Ⅳ is expressed in rabbit corneal endothelium, which could contribute to the transendothelial HCO 3 - flux that is necessary to maintain corneal hydration and transparency.
基金supported by the National Natural Science Foundation of China(Grant No.41173091)National Key Basic Research Program of China(Grant No.2013CB956702)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘We investigated the differences in the gene expression of carbonic anhydrase （CA） and cysteine synthase （CysM） between two weathering conditions, with either soluble potassium or insoluble potassium. We cultured a strain of A. niger by adopting a variant Czapek medium （using NazHPO4 as a substitute for KzHPO4） in two groups, Group A （containing silicate minerals bearing potassium but without KC1） and Group B （with KCI） . We extracted the mRNAs of CA and CysM from these two groups and performed real-time quantitative polymerase chain reactions （RT-qPCR）. We constructed relative standard curves by using glyceraldehyde-3-phosphate dehydrogenase （GAPDH） as the reference to confirm a consistent amplification effi- ciency of the target genes （CA and CysM） and the reference gene and quantified the gene expression of the targets in a relative manner. Our results showed that CA and CysM in Group A were upregulated for 1.7 times and 11.7 times, respectively, com- pared with those in Group B. Furthermore, we also analyzed some metabolic pathways and functions of the A. niger-induced weathering of potassium-bearing minerals, which involved the synthesizing of these two enzymes. Thus our work provides materials for further study of the roles of A. niger in the metabolic regulation during the weathering process of potassi- um-beating minerals.
文摘Pseudobranch function has long interested scientists, but its role has yet to be elucidated. Several studies have suggested that pseudobranchs serve respiratory, osmoregulatory, and sensory functions. This work investigated the immunolocalization of pseudobranch carbonic anhydrase （CA） in the teleost fish species rainbow trout （Oncor- hynchus mykiss） to clarify its physiological function. CA was purified from rainbow trout gills O. mykiss and specific antibodies were raised. Immunoblotting between tissue homogenates of pseudobrench and gill CA antibodies showed specific immunostaining with only one band corresponding to CA in the pseudobranch homogenate. Results of im- munohistochemical technique revealed that CA was distributed within pseudobranch cells and more precisely in the apical parts （anti-vascular） of cells. The basal （vascular） parts of cells, tubular system, blood capillaries, and pillar cells were not immunostained. Immunocytochemistry confirmed these results and showed that some CA enzyme was cytoplasmic and the remainder was linked to membranous structures. The results also showed that the lacunar tissue tayers did not display immunoperoxidase activity. Our results indicated that pseudobranch CA may have a function related to the extracellular medium wherein CA intervenes with the mechanism of stimulation of afferent nerve fibers.
