Allozymes of eleven species of Megophryinae in China were examined electrophoretically to investigate genetic diversity and phylogenetic relationships. Fourteen enzymes, presumptively coded by 24 loci were detected to...Allozymes of eleven species of Megophryinae in China were examined electrophoretically to investigate genetic diversity and phylogenetic relationships. Fourteen enzymes, presumptively coded by 24 loci were detected to be variable. Gene frequencies of each population at each locus were presented. The commonly used measure of genetic diversity, the average heterozygosity (H) were calculated based on gene frequencies. The results indicated that Megophryinae had a high level of genetic diversity in amphibians, an average H of 0.18, ranging from 0.058 to 0.28. Nei's (1978) genetic distances(Nei's D) were calculated for all possible population pairs. A dendrogram of 13 populations representing 11 species, 3 genera of Megophryinae were derived and presented by using UPGMA, based on Nei' s D. The assignment of Ophryophryne as a distinct genus were supported by an average Nei's D of 1.4067 which separated O. microstoma from all other populations.Subdivision of Brachytarsophrys from Megophrys was not supported by this study. Within Megophrys, three groups were recognized: (1)M. lateralis, M. giganticus and M. longipes; (2)M. palpebralespineosa, M. boettgeri and M. parva;(3) M. minor and M. kuatunensis. Three populations of M. omeimontis were closely related and share a clade independent from all other Megophrys, and B. feae as well.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
基金This work was financially supported by Natural Science Foundation of China.
文摘Allozymes of eleven species of Megophryinae in China were examined electrophoretically to investigate genetic diversity and phylogenetic relationships. Fourteen enzymes, presumptively coded by 24 loci were detected to be variable. Gene frequencies of each population at each locus were presented. The commonly used measure of genetic diversity, the average heterozygosity (H) were calculated based on gene frequencies. The results indicated that Megophryinae had a high level of genetic diversity in amphibians, an average H of 0.18, ranging from 0.058 to 0.28. Nei's (1978) genetic distances(Nei's D) were calculated for all possible population pairs. A dendrogram of 13 populations representing 11 species, 3 genera of Megophryinae were derived and presented by using UPGMA, based on Nei' s D. The assignment of Ophryophryne as a distinct genus were supported by an average Nei's D of 1.4067 which separated O. microstoma from all other populations.Subdivision of Brachytarsophrys from Megophrys was not supported by this study. Within Megophrys, three groups were recognized: (1)M. lateralis, M. giganticus and M. longipes; (2)M. palpebralespineosa, M. boettgeri and M. parva;(3) M. minor and M. kuatunensis. Three populations of M. omeimontis were closely related and share a clade independent from all other Megophrys, and B. feae as well.
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.
