Serial analysis of gene expression (SAGE) is an effective method of determining gene expression profiles of tissues and organs under different conditions. In this paper, the detail protocol of SAGE was introduced and some modified procedure of SAGE was reviewed.
Gene Expression Profiling ; methods

No abstract available.
Gene Expression Profiling* ; RNA ; Transcriptome*

Humans ; Transcriptome ; Gene Expression Profiling

OBJECTIVETo develop the methodology of gene chip to analyse genes involved in aflatoxin biosynthesis.

METHODSIn comparing reversed transcriptional PCR with gene chip, the gene chip was used to detect genes involved in aflatoxin biosynthesis.

RESULTSAfter arrayed the slide was incubated in water for 2 hours, exposed to a 650 mJ/cm2 of ultraviolet irradiation in the strata-linker for 30 s, roasted under 80 degrees C for 2 hours in oven, pre-hybridized for 45 minutes and dealt with other procedures. Finally, the slide was hybridized with fluor-derivatized sample at 42 degrees C for 16 hours.

CONCLUSIONWith the reasonable probe design and applicable protocol, the gene chip was prepared effectively for research on genes involved in aflatoxin biosynthesis.

It is generally considered that various regulatory activities between genes are contained in the gene expression datasets. Therefore, the underlying gene regulatory relationship and the biologically useful information can be found by modeling the gene regulatory network from the gene expression data. In our study, two unsupervised matrix factorization methods, independent component analysis (ICA) and nonnegative matrix factorization (NMF), were proposed to identify significant genes and model the regulatory network using the microarray gene expression data of Alzheimer's disease (AD). By bio-molecular analyzing of the pathways, the differences between ICA and NMF have been explored and the fact, which the inflammatory reaction is one of the main pathological mechanisms of AD, is also emphasized. It was demonstrated that our study gave a novel and valuable method for the research of early detection and pathological mechanism, biomarkers' findings of AD.
Algorithms ; Alzheimer Disease ; genetics ; Gene Expression Profiling ; methods ; Humans

Benzene ; toxicity ; Gene Expression Profiling ; Oligonucleotide Array Sequence Analysis

BACKGROUNDClustering is a useful exploratory technique for interpreting gene expression data to reveal groups of genes sharing common functional attributes. Biologists frequently face the problem of choosing an appropriate algorithm. We aimed to provide a standalone, easily accessible and biologically oriented criterion for expression data clustering evaluation.

METHODSAn external criterion utilizing annotation based similarities between genes is proposed in this work. Gene ontology information is employed as the annotation source. Comparisons among six widely used clustering algorithms over various types of gene expression data sets were carried out based on the criterion proposed.

RESULTSThe rank of these algorithms given by the criterion coincides with our common knowledge. Single-linkage has significantly poorer performance, even worse than the random algorithm. Ward's method archives the best performance in most cases.

CONCLUSIONSThe criterion proposed has a strong ability to distinguish among different clustering algorithms with different distance measurements. It is also demonstrated that analyzing main contributors of the criterion may offer some guidelines in finding local compact clusters. As an addition, we suggest using Ward's algorithm for gene expression data analysis.

The rhizome of Panax japonicus var. major have been used as the natural medicinal agent by Chinese traditional doctors for more than thousand years. Most of the therapeutic effects of P. japonicus var. major had been reported due to the presence of tetracyclic or pentacyclic triterpene saponins. In this study, Illumina pair-end RNA-sequencing and de novo splicing were done in order to understand the pathway of triterpenoid saponins in this species. The valid reads data of 15. 6 Gb were obtained. The 62 240 unigenes were finally obtained by de novo splicing. After annotation, we discovered 19 unigenes involved in ginsenoside backbone biosynthesis. Additionally, 69 unigenes and 18 unigenes were predicted to have potential function of cytochrome P450 and UDP-glycosyltransferase based on the annotation results, which may encode enzymes responsible for ginsenoside backbone modification. This study provides global expressed datas for P. japonicus var. major, which will contribute significantly to further genome-wide research and analysis for this species.
Gene Expression Profiling ; Panax ; genetics ; Saponins ; biosynthesis ; Sequence Analysis, RNA

Aesculus chinensis belongs to Hippocastanaceae family,bears medicinal and ornamental values. The oleanane type triterpenoid saponin aescin is regarded as active ingredient and accumulated in seed. In order to understand its molecular basis of the triterpenoid biosynthesis,we used high-throughput sequencing under Illumina Hi Seq 2000 platform to obtain the transcriptome data of seed and flower from A. chinensis to further mine the genes involved in its metabolic pathway. Unigene's de novo splicing was performed using Trinity software; the transcriptome results were annotated with KEGG database to predict the specific pathways of the aescin triterpenoid metabolism. Terpenoid and triterpenoid pathways were found from transcriptome data,and forty seven and twenty seven corresponding genes were uncovered respectively. It was found that there are eight kinds of enzymes related to the terpenoid metabolism pathway precursors and three kinds of enzymes related to the triterpenoid metabolism pathway. In this study,five genes corresponding to triterpene cyclase were analyzed in A. chinensis for the first time,which may participate in the synthesis of triterpenoid. It' s revealed that there were thirty three differential genes associated with the ko00900 and ko00909 pathways by analysis on the difference in transcriptome expression between seeds and flowers; seventeen unigenes were up-regulated and sixteen unigenes were down-regulated in the seeds relative to flowers. In this study, qRT-PCR experiments were used to verify the expression of three key enzyme genes of SQE( Unigene25806),HMGS( Unigene36710),and β-AS( Unigene33291). The results of qRT-PCR were consistent with the transcriptome data. The candidate genes related to triterpenoid saponin aescin synthesis in A. chinensis found in this study can provide theoretical basis for the metabolism synthesis and regulation of aescin.
Aesculus ; Flowers ; Gene Expression Profiling ; Saponins ; Transcriptome ; Triterpenes

Platycodon grandiflorum is a medicinal and edible medicinal material. Our study is aimed to explore the differences in the gene expression of P. grandiflorum in different growth years, and the expression rules of key genes in the biosynthesis of the main active substances of P. grandiflorum. Illumina Hiseq 4000 sequencing platform was used to sequence the transcriptome of P. grandiflorum in different years. Then, 59 654 unigenes were obtained through filtering, assembly, splicing and bioinformatics analysis of the sequencing data, of which 1 671 unigenes were differentially expressed between at least two samples. The results of cluster analysis showed that there was a great difference in the gene expression of P. grandiflorum from one-year-old to two/three-year-old. There were 1 128 different genes between one-and three-year old P. grandiflorum, and only 57 different genes between two-and three-year-old P. grandiflorum. KEGG enrichment results showed that the differential genes of P. grandiflorum in different years were mainly concentra-ted in the biosynthesis of sesquiterpenes and triterpenes, and the biosynthesis of terpenoid skeletons. In the triterpenoid biosynthesis-related pathways, a total of 15 unigenes were identified, involving 5 enzymes. The expression levels of ACAT, HMGR, FDFT1, SQLE decreased with the increase of the growth year of P. grandiflorum. The expression of HMGS was the highest in the one-year-old P. grandiflorum, followed by the three-year-old sample. This study provides useful data for the development of P. grandiflorum, and also provides a basis for the study of related genes in the biosynthetic pathway of platycodin.
Gene Expression Profiling ; Plant Roots ; Platycodon/genetics* ; Saponins ; Transcriptome ; Triterpenes