Mitochondrial oxaloacetate transporter protein encoded by OAT gene transports oxaloacetate from cytoplasm into mitochondria. To investigate the primary effects of OAT gene on relative metabolism in Aspergillus niger, ...Mitochondrial oxaloacetate transporter protein encoded by OAT gene transports oxaloacetate from cytoplasm into mitochondria. To investigate the primary effects of OAT gene on relative metabolism in Aspergillus niger, a oat-deleted mutant was derived from wild-type A. niger ATCC1015 using the double-crossover chromosome replacement technique. Then batch fermentation was performed to evaluate the mutant. Compared with the wild type, the mutant showed lower organic acids production, with the experimental data that the production of pyruvate and 2-ketoglutarate decreased by 31.6% and 35.7%, respectively, and by contrast, the mutant showed higher glycerol formation. The results suggest that OAT gene plays significant roles on metabolism in A. niger.展开更多
In recent years, a great deal of interest has been focused on nitrogen-containing extractants for the separation of actinides from lanthanides. In this study, we synthesized a polyazamacrocycle-type C8-cyclen ligand c...In recent years, a great deal of interest has been focused on nitrogen-containing extractants for the separation of actinides from lanthanides. In this study, we synthesized a polyazamacrocycle-type C8-cyclen ligand comprising four tertiary alkyl amino groups, for the extraction of Am3+ and Eu3+. The C8-cyclen demonstrated a weak ability to extract and separate Am3+ and Eu3+ that increased with the increasing "softness" of the aqueous anions. The extraction behavior of Am3+ and Eu3+ indicated coordination interactions between the C8-cyclen and the Am3+ and Eu3+ ions. The suppression of Am3+ or Eu3+ extraction by acid depended on the media anions involved.展开更多
Streptomyces are the soil-dwelling bacteria with a complex lifecycle and a considerable ability to produce a variety of secondary metabolites.Osmoregulation is important for their lifecycle in nature.In the genome of ...Streptomyces are the soil-dwelling bacteria with a complex lifecycle and a considerable ability to produce a variety of secondary metabolites.Osmoregulation is important for their lifecycle in nature.In the genome of Streptomyces coelicolor M145,SCO3128(encodes a putative fatty acid desaturase),SCO3129(encodes a putative TetR family regulator)and SCO3130(encodes a putative L-carnitine dehydratase)constitute a transcriptional unit,and its transcript was found to be in response to osmotic stress.Disruption of SCO3130 led to a bald phenotype on MMG medium and the mycelia lysis on the edge of the colony when KCl/NaCl was added to the medium.These results indicated that SCO3130 is important for the osmotic stress resistance in S.coelicolor.Transcriptional analysis and electrophoretic mobility shift assays(EMSA)demonstrated that SCO3129 repressed the transcription of SCO3128-3130 operon through directly binding to the promoter region of SCO3128,indicating that SCO3129 regulates the transcription of SCO3128-3130 in response to osmotic stress.展开更多
文摘Mitochondrial oxaloacetate transporter protein encoded by OAT gene transports oxaloacetate from cytoplasm into mitochondria. To investigate the primary effects of OAT gene on relative metabolism in Aspergillus niger, a oat-deleted mutant was derived from wild-type A. niger ATCC1015 using the double-crossover chromosome replacement technique. Then batch fermentation was performed to evaluate the mutant. Compared with the wild type, the mutant showed lower organic acids production, with the experimental data that the production of pyruvate and 2-ketoglutarate decreased by 31.6% and 35.7%, respectively, and by contrast, the mutant showed higher glycerol formation. The results suggest that OAT gene plays significant roles on metabolism in A. niger.
基金supported by the National Natural Science Foundation of China(91226110)the Program for Changjiang Scholars and Innovative Research Team in University
文摘In recent years, a great deal of interest has been focused on nitrogen-containing extractants for the separation of actinides from lanthanides. In this study, we synthesized a polyazamacrocycle-type C8-cyclen ligand comprising four tertiary alkyl amino groups, for the extraction of Am3+ and Eu3+. The C8-cyclen demonstrated a weak ability to extract and separate Am3+ and Eu3+ that increased with the increasing "softness" of the aqueous anions. The extraction behavior of Am3+ and Eu3+ indicated coordination interactions between the C8-cyclen and the Am3+ and Eu3+ ions. The suppression of Am3+ or Eu3+ extraction by acid depended on the media anions involved.
基金We are grateful to Prof.Keith Chater(John Innes Centre,Norwich,UK)for providing E.coli ET12567(pUZ8002)Prof.Keqian Yang(Institute of Microbiology,CAS)for pIMEP.This work was supported by grants from the National Natural Science Foundation of China(No.31170088).
文摘Streptomyces are the soil-dwelling bacteria with a complex lifecycle and a considerable ability to produce a variety of secondary metabolites.Osmoregulation is important for their lifecycle in nature.In the genome of Streptomyces coelicolor M145,SCO3128(encodes a putative fatty acid desaturase),SCO3129(encodes a putative TetR family regulator)and SCO3130(encodes a putative L-carnitine dehydratase)constitute a transcriptional unit,and its transcript was found to be in response to osmotic stress.Disruption of SCO3130 led to a bald phenotype on MMG medium and the mycelia lysis on the edge of the colony when KCl/NaCl was added to the medium.These results indicated that SCO3130 is important for the osmotic stress resistance in S.coelicolor.Transcriptional analysis and electrophoretic mobility shift assays(EMSA)demonstrated that SCO3129 repressed the transcription of SCO3128-3130 operon through directly binding to the promoter region of SCO3128,indicating that SCO3129 regulates the transcription of SCO3128-3130 in response to osmotic stress.
