The paper reviews the recent advances in studying grouper nutrition requirement for the development of cost-effective and environmentally friendly artificial diets. It consists of seven parts: protein and amino acid, ...The paper reviews the recent advances in studying grouper nutrition requirement for the development of cost-effective and environmentally friendly artificial diets. It consists of seven parts: protein and amino acid, lipid and essential fatty acid, carbohydrate, vitamin, mineral, alternative protein source, broodstock and larval nutrition. The review provides some basic information for further investigation of nutrient requirements of groupers.展开更多
The human norepinephrine transporter(NET) gene was cloned and structurally analyzed. The far 5’ fragment containing exon 1 (a non-coding exon) and exon 2 was sequenced. The transcription start site of the gene in hum...The human norepinephrine transporter(NET) gene was cloned and structurally analyzed. The far 5’ fragment containing exon 1 (a non-coding exon) and exon 2 was sequenced. The transcription start site of the gene in human brain stem tissue was determined by primer extension analysis. It was found that the gene could be transcribed from multiple starting points. The 5’ flanking sequence contains a proximal G-C rich region, one possible GSG elemeflt and several SP1 sites. However it does not contain TATA box and CAAT box motifS. Gel shift analysis with nuclear extracts from different tissues of mouse shows that the G-C rich region may be involved in tissue specific expression of the gene.展开更多
Objective: To study the effect of glucocorticoid on the promoter of the pre-receptor glucocorticoid metabolizing enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) gene. Methods: The 1. 2 kb length sequence u...Objective: To study the effect of glucocorticoid on the promoter of the pre-receptor glucocorticoid metabolizing enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) gene. Methods: The 1. 2 kb length sequence upstream to the transcription start site of the 11β-HSD1 gene was amplified with polymerase chain reaction (PCR) and then was cloned into pBLCAT6 plasmid carrying chloramphenicol acetyltransferase ( CAT) reporter gene. The plasmid pBLCAT6 carrying the promoter and reporter gene was used to transfect HeLa cells to study the regulation of 11β-HSD1 gene expression by glucocorticoids in terms of reporter gene expression. Results: PCR showed that there was a complete alignment of the amplified sequence with the sequence 1. 2 kb upstream to the transcription start site of 11β-HSD1 gene. When cloned into pBLCAT6 plasmid carrying the reporter gene, this part of the promoter is functional in terms of regulation of reporter gene expression upon transfection into HeLa cells. The synthetic glucocorticoid-dexamethasone induced the reporter gene expression in the system described above, which was blocked by glucocorticoid receptor antagonist RU486. Conclusion: Glucocorticoids can modulate the expression of 11β-HSD1 through a mechanism involving activation of GR and interaction of the promoter of 11β-HSD1 gene.展开更多
On arrival in the Arctic, migrant birds must adjust their physiology and behavior to unpredictable snow cover, weather, food sources and predator pressure. In other words they must be resistant to environmental pertur...On arrival in the Arctic, migrant birds must adjust their physiology and behavior to unpredictable snow cover, weather, food sources and predator pressure. In other words they must be resistant to environmental perturbations (stress) so that they can migrate to their tundra nesting areas and settle on territories as soon as possible. They can then begin breeding as soon as when environmental conditions become favorable. They do this partly by using micro-habitats such as areas where snow depth is low, and patches of tundra that melt out rapidly (especially near willows Salix sp). Ground temperatures increase dramatically within hours after exposure to sun; and invertebrate activity begins simultaneously. Wind speeds are attenuated almost completely within 10 cm of the ground in willows and tussock tundra. The combination of these conditions provides an ideal refuge, especially for passerine migrants in early spring. However, if conditions worsen, the birds can leave. There are adjustments of the adrenocortical responses to stress because arctic conditions in spring are potentially severe, at least compared with wintering grounds to the south. Secretion of corticosterone in response to acute stress is enhanced at arrival in males, accompanied by a decrease in sensitivity to negative feedback and a change in responsiveness of the adrenal cortex cells to adrenocorticotropin. There is also an increase in levels of corticosterone-binding globulin (CBG) so that the actions of corticosterone are buffered according to the severity of environmental conditions. Regulation at the level of genomic receptors, particularly the low affinity glucocorticosteroid-like receptor for corticosterone in brain and liver, may be important; and non-genomic actions of corticosterone may play a major role too. In other words, the hormone-behavior system associated with arrival biology is highly flexible.展开更多
文摘The paper reviews the recent advances in studying grouper nutrition requirement for the development of cost-effective and environmentally friendly artificial diets. It consists of seven parts: protein and amino acid, lipid and essential fatty acid, carbohydrate, vitamin, mineral, alternative protein source, broodstock and larval nutrition. The review provides some basic information for further investigation of nutrient requirements of groupers.
文摘The human norepinephrine transporter(NET) gene was cloned and structurally analyzed. The far 5’ fragment containing exon 1 (a non-coding exon) and exon 2 was sequenced. The transcription start site of the gene in human brain stem tissue was determined by primer extension analysis. It was found that the gene could be transcribed from multiple starting points. The 5’ flanking sequence contains a proximal G-C rich region, one possible GSG elemeflt and several SP1 sites. However it does not contain TATA box and CAAT box motifS. Gel shift analysis with nuclear extracts from different tissues of mouse shows that the G-C rich region may be involved in tissue specific expression of the gene.
基金Supported by the National Natural Science Foundation of China(No.39970285),Shanghai Science and Technology Development Project(No.99JC14036)
文摘Objective: To study the effect of glucocorticoid on the promoter of the pre-receptor glucocorticoid metabolizing enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) gene. Methods: The 1. 2 kb length sequence upstream to the transcription start site of the 11β-HSD1 gene was amplified with polymerase chain reaction (PCR) and then was cloned into pBLCAT6 plasmid carrying chloramphenicol acetyltransferase ( CAT) reporter gene. The plasmid pBLCAT6 carrying the promoter and reporter gene was used to transfect HeLa cells to study the regulation of 11β-HSD1 gene expression by glucocorticoids in terms of reporter gene expression. Results: PCR showed that there was a complete alignment of the amplified sequence with the sequence 1. 2 kb upstream to the transcription start site of 11β-HSD1 gene. When cloned into pBLCAT6 plasmid carrying the reporter gene, this part of the promoter is functional in terms of regulation of reporter gene expression upon transfection into HeLa cells. The synthetic glucocorticoid-dexamethasone induced the reporter gene expression in the system described above, which was blocked by glucocorticoid receptor antagonist RU486. Conclusion: Glucocorticoids can modulate the expression of 11β-HSD1 through a mechanism involving activation of GR and interaction of the promoter of 11β-HSD1 gene.
文摘On arrival in the Arctic, migrant birds must adjust their physiology and behavior to unpredictable snow cover, weather, food sources and predator pressure. In other words they must be resistant to environmental perturbations (stress) so that they can migrate to their tundra nesting areas and settle on territories as soon as possible. They can then begin breeding as soon as when environmental conditions become favorable. They do this partly by using micro-habitats such as areas where snow depth is low, and patches of tundra that melt out rapidly (especially near willows Salix sp). Ground temperatures increase dramatically within hours after exposure to sun; and invertebrate activity begins simultaneously. Wind speeds are attenuated almost completely within 10 cm of the ground in willows and tussock tundra. The combination of these conditions provides an ideal refuge, especially for passerine migrants in early spring. However, if conditions worsen, the birds can leave. There are adjustments of the adrenocortical responses to stress because arctic conditions in spring are potentially severe, at least compared with wintering grounds to the south. Secretion of corticosterone in response to acute stress is enhanced at arrival in males, accompanied by a decrease in sensitivity to negative feedback and a change in responsiveness of the adrenal cortex cells to adrenocorticotropin. There is also an increase in levels of corticosterone-binding globulin (CBG) so that the actions of corticosterone are buffered according to the severity of environmental conditions. Regulation at the level of genomic receptors, particularly the low affinity glucocorticosteroid-like receptor for corticosterone in brain and liver, may be important; and non-genomic actions of corticosterone may play a major role too. In other words, the hormone-behavior system associated with arrival biology is highly flexible.
