Fish of the superfamily Cobitoidea sensu stricto （namely Ioaches） exhibit extremely high diversity of color patterns, but so far little is known about their evolutionary mechanism. Melanocortin 1 receptor gene （MCI...Fish of the superfamily Cobitoidea sensu stricto （namely Ioaches） exhibit extremely high diversity of color patterns, but so far little is known about their evolutionary mechanism. Melanocortin 1 receptor gene （MCIR） plays an important role during the synthesis of melanin and formation of animal body color patterns. In this study, we amplified and sequenced the partial MCIR gene for 44 loach individuals representing 31 species of four families. Phylogenetic analyses yielded a topology congruent with previous studies using multiple nuclear loci, showing that each of the four families was monophyletic with sister relationships of Botiidae＋ （Cobitidae＋（Balitoridae＋Nemacheilidae））. Gene evolutionary analyses indicated that MCIR in Ioaches was under purifying selection pressure, with various sites having different dNIds values. Both Botiidae and Cobitidae had lower dN/ds values than those of background lineages, suggesting their evolution might be strongly affected by purifying selection pressure. For Balitoddae and Nemacheilidae, both had larger dNIds values than those of background lineages, suggesting they had a faster evolutionary rate under more relaxed selection pressure. Consequently, we inferred that the relatively stable color patterns in Botiidae and Cobitidae might result from the strong purifying selection pressure on the MC1R gene, whereas the complicated and diverse color patterns in Balitoridae and Nemacheilidae might be associated with the relaxed selection pressure. Given the easy experimental procedure for the partial MCTR gene and its excellent performance in reconstructing phylogeny, we suggest this gene could be used as a good molecular marker for the phylogenetic study of fish species.展开更多
Background： Intermittent hypoxia （IH） is a key element of obstructive sleep apnea （OSA） that can lead to disorders in the liver. In this study, IH was established in a rat model to examine its effects on the expr...Background： Intermittent hypoxia （IH） is a key element of obstructive sleep apnea （OSA） that can lead to disorders in the liver. In this study, IH was established in a rat model to examine its effects on the expression of hepatic cytochrome P450 （CYP） and CYP regulators, including nuclear receptors. Methods： Hematoxylin and eosin staining was conducted to analyze the general pathology of the liver of rats exposed to IH. The messenger RNA （mRNA） expression levels of inflammatory cytokines, CYPs, nuclear factor-κB （NF-κB）, and nuclear factors in the liver were measured by quantitative reverse transcription polymerase chain reaction. Results： We found inflammatory infiltrates in the liver of rats exposed to IH. The mRNA expression level of interleukin-1beta was increased in the liver of the IH-exposed rats （0.005 ± 0.001 vs. 0.038 ± 0.008, P = 0.042）, whereas the mRNA expression level of Cyp1a2 was downregulated （0.022 ± 0.002 vs. 0.0050 ± 0.0002, P = 0.029）. The hepatic level of transcription factor NF-κB was also reduced in the IH group relative to that in the control group, but the difference was not statistically significant and was parallel to the expression of the pregnane X receptor and constitutive androstane receptor. However, the decreased expression of the glucocorticoid receptor upon IH treatment was statistically significant （0.056 ± 0.012 vs. 0.032 ± 0.005, P = 0.035）. Conclusions： These results indicate a decrease in expression of hepatic CYPs and their regulator GR in rats exposed to IH. Therefore, this should be noted for patients on medication, especially those on drugs metabolized via the hepatic system, and close attention should be paid to the liver function of patients with OSA-associated IH.展开更多
基金supported by the National Natural Science Foundation of China(NSFC 31272306,31400359,31401968)
文摘Fish of the superfamily Cobitoidea sensu stricto （namely Ioaches） exhibit extremely high diversity of color patterns, but so far little is known about their evolutionary mechanism. Melanocortin 1 receptor gene （MCIR） plays an important role during the synthesis of melanin and formation of animal body color patterns. In this study, we amplified and sequenced the partial MCIR gene for 44 loach individuals representing 31 species of four families. Phylogenetic analyses yielded a topology congruent with previous studies using multiple nuclear loci, showing that each of the four families was monophyletic with sister relationships of Botiidae＋ （Cobitidae＋（Balitoridae＋Nemacheilidae））. Gene evolutionary analyses indicated that MCIR in Ioaches was under purifying selection pressure, with various sites having different dNIds values. Both Botiidae and Cobitidae had lower dN/ds values than those of background lineages, suggesting their evolution might be strongly affected by purifying selection pressure. For Balitoddae and Nemacheilidae, both had larger dNIds values than those of background lineages, suggesting they had a faster evolutionary rate under more relaxed selection pressure. Consequently, we inferred that the relatively stable color patterns in Botiidae and Cobitidae might result from the strong purifying selection pressure on the MC1R gene, whereas the complicated and diverse color patterns in Balitoridae and Nemacheilidae might be associated with the relaxed selection pressure. Given the easy experimental procedure for the partial MCTR gene and its excellent performance in reconstructing phylogeny, we suggest this gene could be used as a good molecular marker for the phylogenetic study of fish species.
文摘Background： Intermittent hypoxia （IH） is a key element of obstructive sleep apnea （OSA） that can lead to disorders in the liver. In this study, IH was established in a rat model to examine its effects on the expression of hepatic cytochrome P450 （CYP） and CYP regulators, including nuclear receptors. Methods： Hematoxylin and eosin staining was conducted to analyze the general pathology of the liver of rats exposed to IH. The messenger RNA （mRNA） expression levels of inflammatory cytokines, CYPs, nuclear factor-κB （NF-κB）, and nuclear factors in the liver were measured by quantitative reverse transcription polymerase chain reaction. Results： We found inflammatory infiltrates in the liver of rats exposed to IH. The mRNA expression level of interleukin-1beta was increased in the liver of the IH-exposed rats （0.005 ± 0.001 vs. 0.038 ± 0.008, P = 0.042）, whereas the mRNA expression level of Cyp1a2 was downregulated （0.022 ± 0.002 vs. 0.0050 ± 0.0002, P = 0.029）. The hepatic level of transcription factor NF-κB was also reduced in the IH group relative to that in the control group, but the difference was not statistically significant and was parallel to the expression of the pregnane X receptor and constitutive androstane receptor. However, the decreased expression of the glucocorticoid receptor upon IH treatment was statistically significant （0.056 ± 0.012 vs. 0.032 ± 0.005, P = 0.035）. Conclusions： These results indicate a decrease in expression of hepatic CYPs and their regulator GR in rats exposed to IH. Therefore, this should be noted for patients on medication, especially those on drugs metabolized via the hepatic system, and close attention should be paid to the liver function of patients with OSA-associated IH.
