Antagonising effects of α-ketoglutarate (α-KG) could be attributed to complexing of the reactive nucleophile (CN-) to form cyanohydrin in cyanide intoxication. However, an enormous protection obtained could not be d...Antagonising effects of α-ketoglutarate (α-KG) could be attributed to complexing of the reactive nucleophile (CN-) to form cyanohydrin in cyanide intoxication. However, an enormous protection obtained could not be delineated on account of possible in situ binding of α-KG given intraperitoneally (i.p.) in mice to cyanide administered through the same route. The present study was designed to see the efficacy of a-KG alone or in combination with sodium nitrite (SN) and/or sodium thiosulfate (STS) in male mice exposed to cyanide administered through subcutaneous (s.c.) or inhalation route. A technique for generation of hydrogen cyanide (HCN) is also discussed. On the basis of protection index (PI), defined here as the LD50 of cyanide in protected mice/LD50 of cyanide in unprotected mice and survival time, STS + α-KG regimen was equipotent to the conventional SN + STS regimen. This is further substantiated by effect of α-KG in reducing plasma cyanide levels. The efficacy of α-KG remains undeterred irrespective of the route of cyanide intoxication, while the magnitude of protection varies.展开更多
One mM KCN fully inhibited the activity of cytochrome oxidase and the succinateoxidation in corn mitochondris, while the oxygen uptake of α-ketoglutarate was not affectedat all. In the latter case, a very strong inhi...One mM KCN fully inhibited the activity of cytochrome oxidase and the succinateoxidation in corn mitochondris, while the oxygen uptake of α-ketoglutarate was not affectedat all. In the latter case, a very strong inhibition could occur when both KCN and KSCNwere simultaneously present. After cyanide inhibition of succinate oxidation, the oxygen uptake could subsequentlyreappear by addition of α-ketoglutarate, but at that time the cytochromes c and a stillremained in their reduced state. In contrast to the cyanide-resistance,α-ketoglutarate oxidation was inhibited by antimycin A. It has been suggested that cytochromes a and c are not involved in the cyanide-insensi-tive alternative pathway in corn mitochondria and the branching point is located on the mainrespiratory chain after cytochrome b instead of before it.展开更多
A yeast strain R6 was obtained by the method of thiamine（VB1） auxotrophic negative selection from the edible oil-polluted soil in Zibo, China. Physiological and biochemical experiments revealed that strain R6 shared...A yeast strain R6 was obtained by the method of thiamine（VB1） auxotrophic negative selection from the edible oil-polluted soil in Zibo, China. Physiological and biochemical experiments revealed that strain R6 shared common feature with Rhodotorula mucilaginosa according to the API 20 C AUX yeast identification system which has been tested previously. Furthermore, the 18 S r DNA gene of strain R6 was amplified and sequenced. Phylogenetic analysis based on the 18 S r DNA sequence and the relatives indicated that R6 shared 99% homologies with the members of R. mucilaginosa, suggesting that strain R6 belonged to R. mucilaginosa.Investigation showed that strain R6 possessed the capacity of accumulating exocellular alpha-ketoglutaric acid（alpha-KG）. Finally, the fermentation conditions of R6 to accumulate alpha-KG was optimized by controlling each single fermenting variable and detected through high performance liquid chromatography（HPLC）. Results showed that both VB1 and Ca CO3 in fermentation medium were the key factors influencing the cumulant of alpha-KG. The discovery of natural auxotrophic strain R6 not only broadened the microbial resource which can achieve lots of alpha-KG production through fermentation, but also laid a foundation for further fermentation regulation to achieve excessive alpha-KG accumulation.展开更多
文摘Antagonising effects of α-ketoglutarate (α-KG) could be attributed to complexing of the reactive nucleophile (CN-) to form cyanohydrin in cyanide intoxication. However, an enormous protection obtained could not be delineated on account of possible in situ binding of α-KG given intraperitoneally (i.p.) in mice to cyanide administered through the same route. The present study was designed to see the efficacy of a-KG alone or in combination with sodium nitrite (SN) and/or sodium thiosulfate (STS) in male mice exposed to cyanide administered through subcutaneous (s.c.) or inhalation route. A technique for generation of hydrogen cyanide (HCN) is also discussed. On the basis of protection index (PI), defined here as the LD50 of cyanide in protected mice/LD50 of cyanide in unprotected mice and survival time, STS + α-KG regimen was equipotent to the conventional SN + STS regimen. This is further substantiated by effect of α-KG in reducing plasma cyanide levels. The efficacy of α-KG remains undeterred irrespective of the route of cyanide intoxication, while the magnitude of protection varies.
文摘One mM KCN fully inhibited the activity of cytochrome oxidase and the succinateoxidation in corn mitochondris, while the oxygen uptake of α-ketoglutarate was not affectedat all. In the latter case, a very strong inhibition could occur when both KCN and KSCNwere simultaneously present. After cyanide inhibition of succinate oxidation, the oxygen uptake could subsequentlyreappear by addition of α-ketoglutarate, but at that time the cytochromes c and a stillremained in their reduced state. In contrast to the cyanide-resistance,α-ketoglutarate oxidation was inhibited by antimycin A. It has been suggested that cytochromes a and c are not involved in the cyanide-insensi-tive alternative pathway in corn mitochondria and the branching point is located on the mainrespiratory chain after cytochrome b instead of before it.
基金Supported by the Natural Science Foundation of Shandong Province,China(ZR2010CQ017)Program of Young Teachers Development of Shandong University of Technology~~
文摘A yeast strain R6 was obtained by the method of thiamine（VB1） auxotrophic negative selection from the edible oil-polluted soil in Zibo, China. Physiological and biochemical experiments revealed that strain R6 shared common feature with Rhodotorula mucilaginosa according to the API 20 C AUX yeast identification system which has been tested previously. Furthermore, the 18 S r DNA gene of strain R6 was amplified and sequenced. Phylogenetic analysis based on the 18 S r DNA sequence and the relatives indicated that R6 shared 99% homologies with the members of R. mucilaginosa, suggesting that strain R6 belonged to R. mucilaginosa.Investigation showed that strain R6 possessed the capacity of accumulating exocellular alpha-ketoglutaric acid（alpha-KG）. Finally, the fermentation conditions of R6 to accumulate alpha-KG was optimized by controlling each single fermenting variable and detected through high performance liquid chromatography（HPLC）. Results showed that both VB1 and Ca CO3 in fermentation medium were the key factors influencing the cumulant of alpha-KG. The discovery of natural auxotrophic strain R6 not only broadened the microbial resource which can achieve lots of alpha-KG production through fermentation, but also laid a foundation for further fermentation regulation to achieve excessive alpha-KG accumulation.
