In the present study, the genetic diversity of one selected strain （Pujiang No. 1）, two domesticated populations （GA and HX） and four wild populations （LZ, YN, SS and JL） of blunt snout bream （Megalobrama ambly...In the present study, the genetic diversity of one selected strain （Pujiang No. 1）, two domesticated populations （GA and HX） and four wild populations （LZ, YN, SS and JL） of blunt snout bream （Megalobrama amblycephala） was analyzed using 17 microsatellite markers. The results showed that an average of 4.88-7.65 number of alleles （A）; an average of 3.20-5.33 effective alleles （Ne）; average observed beterozygosity （Ho） of 0.6985-0.9044; average expected beterozygosity （He） of 0.6501--0.7805; and the average polymorphism information content （PIC） at 0.5706-0.7226. Pairwise FST value between populations ranged from 0.0307-0.1451, and Nei＇s standard genetic distance between populations was 0.0938-0.4524. The expected heterozygosities in the domesticated populations （GA and HX） were significantly lower than those found in three wild populations （LZ, SS and JL）, but no difference was detected when compared with the wild YN population. Likewise, no difference was found between the four wild populations or two domesticated populations. The expected heterozygosity in Pujiang No. 1 was higher than the two domesticated populations and lower than the four wild populations. Regarding pairwise Fsr value between populations, permutation test P-values were significant between the GA, HX and PJ populations, but not between the four wild populations. These results showed that the expected beterozygosity in the selected strain of blunt snout bream, after seven generations of selective breeding, was lower than that of wild populations, but this strain retains higher levels of genetic diversity than domesticated populations. The genetic differences and differentiation amongst wild populations, domesticated populations and the genetically improved strain of blunt snout bream will provide important conservation criteria and guide the utilization of germplasm resources.展开更多
Mucins are important components of mucus, which form a natural, physical, biochemical and semipermeable mucosal layer on the epidermis offish gills, skin, and the gastrointestinal tract. As the first step towards char...Mucins are important components of mucus, which form a natural, physical, biochemical and semipermeable mucosal layer on the epidermis offish gills, skin, and the gastrointestinal tract. As the first step towards characterizing the function of Muc2, we cloned a partial Megalobrama amblycephala Muc2 cDNA of 2 175 bp, and analyzed its tissue-specific expression pattern by quantitative real-time PCR （qPCR）. The obtained sequence comprised 41 bp 5＇-untranslated region （5＇-UTR）, 2 134 bp open reading frame encoding a protein of 711 amino acids. BLAST searching and phylogenetic analysis showed that the predicted protein contained several common secreted mucin-module domains （VWD-C8-TIL-VWD-C8） and had high homology with mucins from other vertebrates. Among four candidate reference genes （β-Actin, RP113a, RPII, 18S） for the qPCR, RPII was chosen as an appropriate reference gene because of its lowest variation in different tissues. M. amblycephala Muc2 was mainly expressed in the intestine, in the order （highest to lowest） middle-intestine 〉 fore-intestine 〉 hind-intestine. Muc2 was expressed relatively poorly in other organs （brain, liver, kidney, spleen, skin and gill）. Furthermore, after 20-days of starvation, M. amblycephala Muc2 expressions after refeeding for 0 h, 3 h, 16 h, 3 d, and 10 d were significantly decreased in the three intestinal segments （P〈0.05） at 16 h, and were then upregulated to near the initial level at 10 d.展开更多
Insulin-like growth factor-binding protein 1 （IGFBP-1）, a hypoxia-induced protein, is a member of the IGFBP family that regulates vertebrate growth and development. In this study, full-length IGFBP-la cDNA was clone...Insulin-like growth factor-binding protein 1 （IGFBP-1）, a hypoxia-induced protein, is a member of the IGFBP family that regulates vertebrate growth and development. In this study, full-length IGFBP-la cDNA was cloned from a hypoxia-sensitive Cyprinidae fish species, the blunt snout bream （Megalobrama arnblycephala）. IGFBP-la was expressed in various organs of adult blunt snout bream, including strongly in the liver and weakly in the gonads. Under hypoxia, IGFBP-la mRNA levels increased sharply in the skin, liver, kidney, spleen, intestine and heart tissues of juvenile blunt snout bream, but recovered to normal levels after 24-hour exposure to normal dissolved oxygen. In blunt snout bream embryos, IGFBP-la mRNA was expressed at very low levels at both four and eight hours post-fertilization, and strongly at later stages. Embryonic growth and development rates decreased significantly in embryos injected with IGFBP-la mRNA. The average body length of IGFBP-la-overexpressed embryos was 82.4% of that of the control group, and somite numbers decreased to 85.2%. These findings suggest that hypoxia-induced IGFBP-la may inhibit growth in this species under hypoxic conditions.展开更多
基金supported by the National Natural Science Foundation of China(30630051)Doctoral Research Initial Funding from Shanghai Ocean University(A-2400-11-0186)
文摘In the present study, the genetic diversity of one selected strain （Pujiang No. 1）, two domesticated populations （GA and HX） and four wild populations （LZ, YN, SS and JL） of blunt snout bream （Megalobrama amblycephala） was analyzed using 17 microsatellite markers. The results showed that an average of 4.88-7.65 number of alleles （A）; an average of 3.20-5.33 effective alleles （Ne）; average observed beterozygosity （Ho） of 0.6985-0.9044; average expected beterozygosity （He） of 0.6501--0.7805; and the average polymorphism information content （PIC） at 0.5706-0.7226. Pairwise FST value between populations ranged from 0.0307-0.1451, and Nei＇s standard genetic distance between populations was 0.0938-0.4524. The expected heterozygosities in the domesticated populations （GA and HX） were significantly lower than those found in three wild populations （LZ, SS and JL）, but no difference was detected when compared with the wild YN population. Likewise, no difference was found between the four wild populations or two domesticated populations. The expected heterozygosity in Pujiang No. 1 was higher than the two domesticated populations and lower than the four wild populations. Regarding pairwise Fsr value between populations, permutation test P-values were significant between the GA, HX and PJ populations, but not between the four wild populations. These results showed that the expected beterozygosity in the selected strain of blunt snout bream, after seven generations of selective breeding, was lower than that of wild populations, but this strain retains higher levels of genetic diversity than domesticated populations. The genetic differences and differentiation amongst wild populations, domesticated populations and the genetically improved strain of blunt snout bream will provide important conservation criteria and guide the utilization of germplasm resources.
基金Supported by the National Natural Science Foundation of China(No.31302222)the Earmarked Fund for China Agriculture Research System(No.CARS-46)+1 种基金the Freshwater Fisheries Research Center,CAFS Grant(Nos.2013JBFM10,2013JBFM03)the Natural Sciences Foundation of Jiangsu Province(No.BK2011182)
文摘Mucins are important components of mucus, which form a natural, physical, biochemical and semipermeable mucosal layer on the epidermis offish gills, skin, and the gastrointestinal tract. As the first step towards characterizing the function of Muc2, we cloned a partial Megalobrama amblycephala Muc2 cDNA of 2 175 bp, and analyzed its tissue-specific expression pattern by quantitative real-time PCR （qPCR）. The obtained sequence comprised 41 bp 5＇-untranslated region （5＇-UTR）, 2 134 bp open reading frame encoding a protein of 711 amino acids. BLAST searching and phylogenetic analysis showed that the predicted protein contained several common secreted mucin-module domains （VWD-C8-TIL-VWD-C8） and had high homology with mucins from other vertebrates. Among four candidate reference genes （β-Actin, RP113a, RPII, 18S） for the qPCR, RPII was chosen as an appropriate reference gene because of its lowest variation in different tissues. M. amblycephala Muc2 was mainly expressed in the intestine, in the order （highest to lowest） middle-intestine 〉 fore-intestine 〉 hind-intestine. Muc2 was expressed relatively poorly in other organs （brain, liver, kidney, spleen, skin and gill）. Furthermore, after 20-days of starvation, M. amblycephala Muc2 expressions after refeeding for 0 h, 3 h, 16 h, 3 d, and 10 d were significantly decreased in the three intestinal segments （P〈0.05） at 16 h, and were then upregulated to near the initial level at 10 d.
基金supported by grants from the Key Technologies Research and Development Program of China(2012BAD26B02)National Science Foundation of China(31272633+2 种基金31201760)Special Funding from the Ministry of Agriculture of China(201203081,201203086)Shanghai University Knowledge Service Platform(ZF1206)
文摘Insulin-like growth factor-binding protein 1 （IGFBP-1）, a hypoxia-induced protein, is a member of the IGFBP family that regulates vertebrate growth and development. In this study, full-length IGFBP-la cDNA was cloned from a hypoxia-sensitive Cyprinidae fish species, the blunt snout bream （Megalobrama arnblycephala）. IGFBP-la was expressed in various organs of adult blunt snout bream, including strongly in the liver and weakly in the gonads. Under hypoxia, IGFBP-la mRNA levels increased sharply in the skin, liver, kidney, spleen, intestine and heart tissues of juvenile blunt snout bream, but recovered to normal levels after 24-hour exposure to normal dissolved oxygen. In blunt snout bream embryos, IGFBP-la mRNA was expressed at very low levels at both four and eight hours post-fertilization, and strongly at later stages. Embryonic growth and development rates decreased significantly in embryos injected with IGFBP-la mRNA. The average body length of IGFBP-la-overexpressed embryos was 82.4% of that of the control group, and somite numbers decreased to 85.2%. These findings suggest that hypoxia-induced IGFBP-la may inhibit growth in this species under hypoxic conditions.
