A normalized full-length cDNA library was constructed from the coralloid roots of Cycas debaoensis by the DSN （duplex-specific nuclease） normalization method combined with the SMART （Switching Mechanism At 5＇ end ...A normalized full-length cDNA library was constructed from the coralloid roots of Cycas debaoensis by the DSN （duplex-specific nuclease） normalization method combined with the SMART （Switching Mechanism At 5＇ end of the RNA Transcript） technique. The titer of the original cDNA library was about 1.5 × 10^6 cfu·mL^-1 and the average insertion size was about 1 kb with a high recombination rate （97%）. The 5011 high-quality expressed sequence tags （ESTs） were obtained from 5393 randomly picked cDNA clones. Clustering and assembly of ESTs resulted in 2984 unique sequences, consisting of 618 contigs and 2366 singlets. EST sequence annotation revealed that 2333 and 1901 unigenes were functionally anno- tated in the NCBI non-redundant database and Swiss-Prot protein database, respectively. Functional analysis demonstrated that 1495 （50.1%） unigenes were associated with 4082 Gene Ontology （GO） terms. A total of 847 unigenes were grouped into 22 Cluster of Orthologous Groups （COG） functional categories. Based on the EST dataset, 22 ESTs that encoded putative receptor-like protein kinase （RLK） genes were screened. Furthermore, a total of 94 simple sequence repeats （SSRs） were discovered, of which 20 loci were successfully amplified in C debaoensis. This study is the first EST analysis for the coralloid roots of C debaoensis and provides a valuable genomic resource for novel gene discovery, gene expression and comparative genomics, conservation and management studies as well as applications in C debaoensis and related cycad species.展开更多
Bifidobacteria play an important role in maintaining human health, and suppress harmful bacteria by controlling the pH of the large intestine. About 14 strains of the Bifidobacteria have been isolated from the faeces ...Bifidobacteria play an important role in maintaining human health, and suppress harmful bacteria by controlling the pH of the large intestine. About 14 strains of the Bifidobacteria have been isolated from the faeces of infants nursed exclusively from the maternal milk （their ages less than 5 months） from commercial French yoghurt （active bifidus] and from milk （celia bifidus） on MRS medium （containing 0.05% cysteine-HC1, with nalidixic acid 2 mg rel）. A total of six strain are strict anaerobic and gram-positive Bifidobacteria, identified as, B. longum （60% of the samples） was the most frequently found species, followed by B. bifidum （21.0%）, B. breve （19%）. These strains were evaluated for potential use as probiotics based on their adhesion to intestinal epithelial cells, resistance towards acidic （resistance to low pH） and bile conditions, pH values ranging from 6.5 to 7, however, these strains are sensitive to the pH 8, Bifidobacterium are mesophiles with optimal growth at 36℃ to 41℃. All isolates studied have a fast growth in glucose.展开更多
基金supported by the Grant(201522)from Shenzhen Urban Management
文摘A normalized full-length cDNA library was constructed from the coralloid roots of Cycas debaoensis by the DSN （duplex-specific nuclease） normalization method combined with the SMART （Switching Mechanism At 5＇ end of the RNA Transcript） technique. The titer of the original cDNA library was about 1.5 × 10^6 cfu·mL^-1 and the average insertion size was about 1 kb with a high recombination rate （97%）. The 5011 high-quality expressed sequence tags （ESTs） were obtained from 5393 randomly picked cDNA clones. Clustering and assembly of ESTs resulted in 2984 unique sequences, consisting of 618 contigs and 2366 singlets. EST sequence annotation revealed that 2333 and 1901 unigenes were functionally anno- tated in the NCBI non-redundant database and Swiss-Prot protein database, respectively. Functional analysis demonstrated that 1495 （50.1%） unigenes were associated with 4082 Gene Ontology （GO） terms. A total of 847 unigenes were grouped into 22 Cluster of Orthologous Groups （COG） functional categories. Based on the EST dataset, 22 ESTs that encoded putative receptor-like protein kinase （RLK） genes were screened. Furthermore, a total of 94 simple sequence repeats （SSRs） were discovered, of which 20 loci were successfully amplified in C debaoensis. This study is the first EST analysis for the coralloid roots of C debaoensis and provides a valuable genomic resource for novel gene discovery, gene expression and comparative genomics, conservation and management studies as well as applications in C debaoensis and related cycad species.
文摘Bifidobacteria play an important role in maintaining human health, and suppress harmful bacteria by controlling the pH of the large intestine. About 14 strains of the Bifidobacteria have been isolated from the faeces of infants nursed exclusively from the maternal milk （their ages less than 5 months） from commercial French yoghurt （active bifidus] and from milk （celia bifidus） on MRS medium （containing 0.05% cysteine-HC1, with nalidixic acid 2 mg rel）. A total of six strain are strict anaerobic and gram-positive Bifidobacteria, identified as, B. longum （60% of the samples） was the most frequently found species, followed by B. bifidum （21.0%）, B. breve （19%）. These strains were evaluated for potential use as probiotics based on their adhesion to intestinal epithelial cells, resistance towards acidic （resistance to low pH） and bile conditions, pH values ranging from 6.5 to 7, however, these strains are sensitive to the pH 8, Bifidobacterium are mesophiles with optimal growth at 36℃ to 41℃. All isolates studied have a fast growth in glucose.
