Construction of full-length cDNA library from Antrodia cinnamomea mycelium and EST sequence analysis / 中草药

Objective: To excavate the terpenoid synthesis and metabolism-related gene function and screen the interaction protein and fingerprint analysis of Antrodia cinnamomea mycelium, a cDNA library from A. cinnamomea mycelia was constructed and the EST sequences were analyzed. Methods: The cDNA library from the A. cinnamomea mycelium was constructed by the Gateway technique. A part of EST sequences about the bioinformatics, functional annotation and EST-SSR were analyzed. Results: The cDNA library of the A. cinnamomea mycelium was constructed successfully. The recombinant rate of the cDNA library was 95%, the titer of the library was 6.1 × 106 cfu/mL, the total cloning number was 1.2 × 107 cfu, the length of cDNA was between 300-2 000 bp with an average length of 1 000 bp. The clones were randomly sequenced and 65 valid ESTs were obtained. After being compared in the Genbank database, 45 ESTs had a definite annotation, and 18 ESTs were unnamed and hypothetical protein. The results with GO functional annotation showed that the ESTs involved the cell composition, transport, catalytic activity, regulation functions and etc. It contained 271 SSRs of all the ESTs in total. The nucleotide repeats in A. cinnamomea were abundant, among which dinucleotide and trinucleotide repeat units were more common accounting for 94.23%. Conclusion: The cDNA library from the A. cinnamomea mycelium and its ESTs related biological information were preliminarily identified, which will provide a theoretical foundation for research the mycelium genomics of A. cinnamomea.

Expression and Characterization of Genes by Expressed Sequence Tag Analysis in the Rat Thymus during Regeneration following Acute Thymic Involution Induced by Cyclophosphamide / 체질인류학회지

The thymus is the central lymphoid organ for the development of bone marrow-derived precursor cells into mature T-cells. Understanding the molecular mechanism of thymic involution and regeneration is critical to develop methods to normalize or improve host immunity from the decreased immune function caused by thymic involution. In this study, the regenerating thymus cDNA library was constructed in the rat from a model of thymic involution and regeneration induced by cyclophosphamide. Expressed sequence tags (ESTs) were obtained by partial sequencing of 700 randomly selected insert-containing clones. A total of 630 ESTs were analyzed, of which 486 ESTs (78%) matched to known genes and 125 ESTs (19%) matched to other ESTs (unknown genes). The 19 ESTs (3%) did not match with any known sequences. The ESTs were grouped into six main functional categories: metabolism (44%), signaling components (20%), membrane transport (7%), cytoskeleton (2%), cell division (2%) and defense (2%). As a result of RT-PCR analysis, expression of putative gene 01, putative E2IG2 gene, musculin and osteoactivin significantly increased in rat thymus during regeneration. The putative gene 01 showed complete homology with mitochondrial ribosomal protein S4 by homology search and multiple alignment of amino acid. These results provide the extensive molecular information on thymus regeneration and will be useful source to identify various genes which may play an important role in the thymus regeneration as well as to clone novel genes. Furthermore, the availability of these data will serve as a basis for further research to understand the molecular mechanism of thymus regeneration.

Characterization of E. coli-induced Genes in Bombyx mori Fatbody using Expressed Sequence Tags Analysis

To accelerate the molecular analysis of specifically induced antibacterial peptide against pathogen (E. coli), cDNA library prepared from the larvae fatbody of Bombyx mori was examined by the expressed sequence tag (EST) analysis. In a total of 722 clones, 653 clones were unique genes. Of 653 unique genes, 43.2% (282/653 ESTs) was identified as characterized genes, 38.1% (249/653 ESTs) as uncharacterized genes, and 18.7% (122/653 ESTs) as novel ESTs. According to the functional categorization of the characterized genes, 36.2% (102/282 ESTs) was antibacterial proteins. The highest expressed peptides, 78.4% of all the expressed antibacterial proteins (80/102 ESTs), belonged to the cecropin family. The antibacterial effect of selected clones representing novel ESTs based on a phylogenetic analysis was examined against various bacterial strains. None of the clones showed significant inhibitory effect to the bacteria tested. These results suggested that most of the novel molecules induced by E. coli may not act as immune-induced antibacterial peptides in the fatbody.

Data mining for simple sequence repeats in expressed sequence tags from Saruma henryi / 中草药

Objective To analyze the simple sequence repeat(SSR)information in expressed sequence tag(EST)resource of Saruma henryi and lay a solid foundation for the development of EST-SSR markers in this species.Methods ESTs of S.henryi were downloaded from GenBank and used to perform the contig assembly using Sequencher 4.8.Uni-ESTs were obtained and screened for SSR-containing unigenes using SciRoKo 3.4.The distributing frequency of the EST-SSRs and the basic characteristics of motifs were analyzed.Results A total of 10 274 ESTs of S.henryi were retrieved and were assembled into 6 643 non-redundant Uni-ESTs with a total length of 5.11?106 bp.In all,the data mining yielded 1 408 SSR loci,which corresponded to 1 232 Uni-ESTs(18.55%).On average,EST-SSRs spanned 22.30 bp,and occurred every 3.63 kb in length.In S.henryi,mononucleotide repeats predominated with an occurrence frequency of 12.24%.Dinucleotide repeats followed with a frequency of 5.01%.The most frequent one was A/T among all the repeat motifs,then followed by AG/CT.Conclusion SSRs in ESTs of S.henryi display a relatively high level of occurrence frequency and show abundance of types.