In this study we assess the maternal genetic diversity and origin of indigenous village chickens from Chad complementing previous phenotypic and biometric measurements studies. We analysed a 387 bp fragment of the mit...In this study we assess the maternal genetic diversity and origin of indigenous village chickens from Chad complementing previous phenotypic and biometric measurements studies. We analysed a 387 bp fragment of the mitochondrial DNA (mtDNA) D-loop region of 181 village chickens from three populations of western Chad (Lake Chad/Hadjer Lamis), central Chad (Guera) and south-west Chad (Pala) and at different poultry markets in N'Djamena. Twenty-five polymorphic sites and 20 haplotypes are identified. Phylogenetic and network analyses group all chicken into a single mtDNA haplogroup D. Comparison with reference sequences shows that this haplogroup is the commonest one observed in chicken and it supports the Indian subcontinent as the maternal center of origin for the village chicken in Chad. Little genetic variation was found within and between populations which is in agreement with a recent and a maternal founding effect for the chicken in the country.展开更多
该文以来自于自然发酵椰子水中生长良好的乳酸菌为研究对象,以来自于病死肉鸡的耐药性致病菌为指示菌进行抑菌活性初筛,再进行耐受性复筛,得到一株优良菌株A32,经鉴定为发酵乳杆菌(Lactobacillus fermentum)。A32在椰子水中能保持旺盛生...该文以来自于自然发酵椰子水中生长良好的乳酸菌为研究对象,以来自于病死肉鸡的耐药性致病菌为指示菌进行抑菌活性初筛,再进行耐受性复筛,得到一株优良菌株A32,经鉴定为发酵乳杆菌(Lactobacillus fermentum)。A32在椰子水中能保持旺盛生长1 d~4 d,活菌数维持8 lg cfu/mL~9 lg cfu/mL,能大量产酸,最低pH值为3.55、总酸最高达17.09 g/L。蛋白酶和高温处理对其抑菌活性几乎不产生影响,上调pH值至5.0时其抑菌活性消失。抑菌活性与其总酸含量呈显著正相关(p<0.05),推测A32所产抑菌物质主要为有机酸类,具体种类有苹果酸、柠檬酸和乳酸等,其中苹果酸比例达64%以上。推测菌株A32在椰子水中高活性抑菌作用可能与其较低的pH值、较高的总酸和苹果酸含量有关。展开更多
文摘In this study we assess the maternal genetic diversity and origin of indigenous village chickens from Chad complementing previous phenotypic and biometric measurements studies. We analysed a 387 bp fragment of the mitochondrial DNA (mtDNA) D-loop region of 181 village chickens from three populations of western Chad (Lake Chad/Hadjer Lamis), central Chad (Guera) and south-west Chad (Pala) and at different poultry markets in N'Djamena. Twenty-five polymorphic sites and 20 haplotypes are identified. Phylogenetic and network analyses group all chicken into a single mtDNA haplogroup D. Comparison with reference sequences shows that this haplogroup is the commonest one observed in chicken and it supports the Indian subcontinent as the maternal center of origin for the village chicken in Chad. Little genetic variation was found within and between populations which is in agreement with a recent and a maternal founding effect for the chicken in the country.
文摘该文以来自于自然发酵椰子水中生长良好的乳酸菌为研究对象,以来自于病死肉鸡的耐药性致病菌为指示菌进行抑菌活性初筛,再进行耐受性复筛,得到一株优良菌株A32,经鉴定为发酵乳杆菌(Lactobacillus fermentum)。A32在椰子水中能保持旺盛生长1 d~4 d,活菌数维持8 lg cfu/mL~9 lg cfu/mL,能大量产酸,最低pH值为3.55、总酸最高达17.09 g/L。蛋白酶和高温处理对其抑菌活性几乎不产生影响,上调pH值至5.0时其抑菌活性消失。抑菌活性与其总酸含量呈显著正相关(p<0.05),推测A32所产抑菌物质主要为有机酸类,具体种类有苹果酸、柠檬酸和乳酸等,其中苹果酸比例达64%以上。推测菌株A32在椰子水中高活性抑菌作用可能与其较低的pH值、较高的总酸和苹果酸含量有关。
