Despite the nutritive value of finfish, the domestic production is inadequate to meet the national demand. Due to the high demand of 2.66 million metric tons per annum for fish, Nigeria imported 740,000 tons in 2007 t...Despite the nutritive value of finfish, the domestic production is inadequate to meet the national demand. Due to the high demand of 2.66 million metric tons per annum for fish, Nigeria imported 740,000 tons in 2007 to supplement the domestic production of 615,507 tons. A study was conducted in Ibadan Metropolis of Oyo State （a land locked state） to determine the consumer preference and pattern of marine fish species consumed. Stratified sampling method was used to select respondents from three income earning levels of the five local government areas in Ibadan Metropolis. Questionnaires were administered to 51 marine fish retailers and 151 households. Data collected was analyzed using descriptive statistics and Tobit regression model. Marine fish sellers ranked horse mackerel （Scomberjaponicus） first and croaker （Pseudotholithus species） the least because it is more priced. Only 10.6% and 13.2% of the households preferred express （Brevortia species） and croaker respectively, but Hake （Gadus gadus） was the least preferred （41.7%）. The household consumed varying proportions of fish species every week. The regression result （R2 = 0.65） showed that married household heads with large household size having lower years/level of education, younger in age and earning lower income are likely to consume more of marine frozen fish species （P 〈 0.01） than others.展开更多
文摘黄酮类化合物是橄榄[Canarium album(Lour.)Raeusch]的重要活性成分,而查尔酮异构酶(Chalcone isomerase,CHI)是黄酮合成的关键酶类之一,了解橄榄查尔酮异构酶基因CHI的密码子偏好模式可为其功能和分子进化研究提供科学依据.采用Codon W和EMBOSS分析橄榄CHI的密码子偏好性参数,并通过有效密码子数(Effective number of codon,ENc)绘图、中性绘图和偏倚分析探讨单双子叶植物CHI密码子偏好性形成的可能因素,同时分别采用SPSS19.0和MEGA5.2基于密码子偏好性和序列相似性进行聚类分析.结果显示:橄榄CHI ENc值、G和C的含量(GC)以及密码子第3位上G和C含量(GC3s)分别为50.89、0.451和0.465,表明其密码子偏好性较弱,但倾向使用富含A和U,并以A或U结尾的密码子;单子叶植物CHI的密码子偏好性普遍高于双子叶植物,基于密码子偏好性和核酸序列相似性均能将单双子叶植物进行较准确的归类;密码子碱基成分和相关性分析发现,物种间CHI密码子偏好性受编码区长度的影响较小,而与碱基的组成密切相关;此外,橄榄CHI与模式生物拟南芥、烟草、大肠杆菌和酵母菌基因组均存在较大的密码子偏好性差异.本研究表明突变压力是单双子叶植物间CHI严格的密码子偏好规律形成的主要作用力,而橄榄CHI外源表达和遗传转化时需要根据宿主基因组偏好模式进行密码子优化和改造.
文摘Despite the nutritive value of finfish, the domestic production is inadequate to meet the national demand. Due to the high demand of 2.66 million metric tons per annum for fish, Nigeria imported 740,000 tons in 2007 to supplement the domestic production of 615,507 tons. A study was conducted in Ibadan Metropolis of Oyo State （a land locked state） to determine the consumer preference and pattern of marine fish species consumed. Stratified sampling method was used to select respondents from three income earning levels of the five local government areas in Ibadan Metropolis. Questionnaires were administered to 51 marine fish retailers and 151 households. Data collected was analyzed using descriptive statistics and Tobit regression model. Marine fish sellers ranked horse mackerel （Scomberjaponicus） first and croaker （Pseudotholithus species） the least because it is more priced. Only 10.6% and 13.2% of the households preferred express （Brevortia species） and croaker respectively, but Hake （Gadus gadus） was the least preferred （41.7%）. The household consumed varying proportions of fish species every week. The regression result （R2 = 0.65） showed that married household heads with large household size having lower years/level of education, younger in age and earning lower income are likely to consume more of marine frozen fish species （P 〈 0.01） than others.
