Validation of housekeeping genes as internal controls for studying the gene expression in Pyropia haitanensis(Bangiales, Rhodophyta) by quantitative real-time PCR

Pyropia haitanensis is an economically important mariculture crop in China and has a high research value for several life phenomena, for example environmental tolerance. To explore the mechanisms underlying these characteristics, gene expression has been investigated at the whole transcriptome level. Gene expression studies using quantitative real-time PCR should start by selecting an appropriate internal control gene; therefore, the absolute expression abundance of six housekeeping genes （18S rRNA （18S）, ubiquitin-conju-ating enzyme （UBC）, actin （ACT）, β-tubulin （TUB）, elongation factors 2 （EF2）, and glyceraldehyde-3-phos- phate dehydrogenase （GAPDH） examined by the quantitative real-time PCR in samples corresponding to different strains, life-cycle stages and abiotic stress treatments. Their expression stabilities were assessed by the comparative cycle threshold （Ct） method and by two different software packages： geNorm and NormFinder. The most stable housekeeping gene is UBC and the least stable housekeeping is GADPH. Thus, it is proposed that the most appropriate internal control gene for expression analyses in P. haitanensis is UBC. The results pave the way for further gene expression analyses of different aspects of P. haitanensis biology including different strains, life-history stages and abiotic stress responses.

Expression profiles of penaeidin from Fenneropenaeus chinensis in response to WSSV and vibrio infection by real-time PCR

Penaeidin from Chinese shrimp (Fenneropenaeus chinensis) has proved to be one of the most important antimicrobial peptides in the bodies of animals. The relative quantitative real-time PCR method is developed to study through time, the mRNA expression profile of penaeidin in the muscle and haemocyte tissue of Chinese shrimp infected with vibrio (Vibrio anguillarum) and WSSV (white spot syndrome virus). Research results showed that the same pathogens infection experiments produced similar gene expression profile in different tissues while different expression profiles appeared in the same tissues infected by different exterior pathogens. In vibrio infection experiments, a 'U' like expression profile resulted. Expression levels of penaeidin increased and surpassed the non-stimulated level, indicating that penaeidin from Chinese shrimp has noticeable antimicrobial activities. In WSSV infection experiments, the expression profile appeared as an inverse 'U' with the expression of penaeidin gradually decreasing to below baseline level after 24 h. The expression of antimicrobial peptides gene in mRNA level in response to virus infection in shrimp showed that international mechanisms of virus to haemocytes and microbial to haemocytes are completely different. Decline of penaeidins expression levels may be due to haemocytes being destroyed by WSSV or that the virus can inhibit the expression of penaeidins by yet undiscovered modes. The expression profiles of penaeidin in response to exterior pathogen and the difference of expression profiles between vibrio and WSSV infection provided some clues to further understanding the complex innate immune mechanism in shrimp.

Selection of Reference Genes for Gene Expression Analysis in Nilaparvata lugens with Different Levels of Virulence on Rice by Quantitative Real-Time PCR

The brown planthopper Nilaparvata lugens Stal （Homoptera： Delphacidae） can cause hopperburn by feeding on rice and also can transmit the grassy stunt disease. Resistant rice varieties have been developed, but several N. lugens strains can recover their virulence to these resistant rice varieties. In the present study, reference genes with stable expression levels in N. lugens populations showed different levels of virulence to susceptible and resistant rice varieties. The expression of six candidate reference genes in N. lugens feeding on susceptible and resistant rice varieties was analyzed. These genes were evaluated for their potential use in the analysis of differential gene expression. Polymerase chain reaction data was generated from N. lugens, including two different treatments （resistant or susceptible rice） and three virulent N. lugens populations. Three software programs （BestKeeper, Normfinder and geNorm） were used to assess the candidate reference genes. Both geNorm and Normfinder identified the genes 18S, E-ACT, E-TUB and a-TUB as the most stable reference genes. BestKeeper identified ETIF1 as the optimal reference gene with the least overall variation, whereas 18S and a-TUB were the second and third most stably expressed genes, respectively. Therefore, we concluded that the genes 18S and a-TUB were the most suitable reference genes in N. lugens. These results will facilitate future transcript profiling studies on N. lugens populations that show variation in virulence levels on different rice varieties.

Detection of gemcitabine-resistant genes expression in lung cancer cell lines using real-time PCR

Objective: To explore the molecular mechanism of gemcitabine-resistance, the relative mRNA expression of five genes related to gemcitabine-resistance was detected in six lung cancer cell lines. Methods: The total RNA was extracted from six lung cancer cell lines GLC-82, NCI-H460, A549, 95-C, 95-D and QG56. Then the cDNA was amplified by real-time quantitative PCR method to quantify the gene expression of RRM1, PTEN, ERCC1, dCK and CDA. The cytotoxicity of gem- citabine to cell lines was tested by MTT method. Results: Among the detected six lung cancer cell lines, the mRNA level of RRM1, PTEN and ERCC1 in lung squamous cell line QG56 was highest, and the IC50 of gemcitabine to QG56 cell line was also highest. Conclusion: The mRNA expression of RRM1, PTEN and ERCC1 was correlated, and the high expression of RRM1 was related to gemcitabine resistance of lung cancer.

Real-Time PCR Technique and Its Application in Quantification of Plant Nucleic Acid Molecules

Real-time PCR is a closed DNA amplification system that skillfully integrates biochemical, photoelectric and computer techniques. Fluorescence data acquired once per cycle provides rapid absolute quantification of initial template copy numbers as PCR products are generated. This technique significantly simplifies and accelerates the process of producing reproducible quantification of nucleic acid molecules. It not only is a sensitive, accurate and rapid quantitative method, but it also provides an easier way to calculate the absolute starting copy number of nucleic acid molecules to be tested. Together with molecular bio-techniques, like microarray, real-time PCR will play a very important role in many aspects of molecular life science such as functional gene analysis and disease molecular diagnostics. This review introduces the detailed principles and application of the real-time PCR technique, describes a recently developed system for exact quantification of AUX/IAA genes In Arabidopsis, and discusses the problems with the real-time PCR process.

Application of Real-time Fluorescent Quantitative PCR in Studies on Plants

Real-Lime fluorescent quantitative PCR is a method for quantitative analysis of gene expression developed in recent years, which has been widely used in various fields such as basic scientific research, clinical diagnosis, disease study, drug research and development since its appearance. It starts relatively late in study on plants, but has already been used for analysis of gene expression in plants and gene identification of exogenous genes. The principles or advantages and dis- advantages of real-time fluorescent quantitative PCR, or its potential problems and condition optimizations in tests were introduced in this study, and then the appli- cation and prospect of real-time fluorescent quantitative PCR in study on plants were also been discussed.

Detection of Survivin mRNA in nasopharyngeal carcinoma by real-time fluorescence quantitative RT-PCR

Objective： To establish the method of real time fluorescence quantitative RT-PCR for detecting the expression of Survivin mRNA in nasopharyngeat carcinoma （NPC） tissues. Methods： The total RNA was extracted from NPC cell line CNE-2 and tissues with Trizol and then been transcribed reversely to cDNA, a method of real time fluorescence quantitative RT-PCR for detecting the expression of Survivin mRNA in NPC tissues had been established, in which chronic nasopharyn-gitis patients＇ nasopharynx tissues treated as control group. Results： The expression of Survivin mRNA all could be detected either in CNE-2 cells, NPC tissues or in chronic nasopharyngitis patients＇ nasopharynx tissues, and there was higher the expression level of Survivin mRNA in NPC tissues than which in chronic nasopharyngitis patients＇ nasopharynx tissues, the difference was significant （P 〈 0.01）. The expression of Survivin mRNA could be detected both in stage Ⅰ ＋ Ⅱ and stage Ⅲ ＋ Ⅳ NPC, and there was no significant difference in relative quantifications of gene expression between these two groups （P 〉 0.05）. There was no relationship between Survivin mRNA expression and age and sex of NPC patients （P 〉 0.05）. Conclusion： Real time fluorescence quantitative RT-PCR is a rapid, effective and high sensitive method for detecting the expression of Survivin mRNA in NPC tissues. The overexpression of Survivin mRNA may play some roles in pathogenesis of NPC.

Selection of Reference Genes in Transcription Analysis of Gene Expression of the Mandarin Fish, Siniperca chuasti

At present, transcription analysis of gene expression commonly uses housekeeping genes as control for normalization. In this study, the expression levels of three housekeeping genes including GAPDH, β-actin, and 18S rRNA in six tissues and five developmental stages of the Mandarin fish Siniperca chuatsi were assayed with quantitative real-time PCR （qPCR）. Differences in expression levels were analyzed using geNorm program. The results demonstrate that β-actin is the most stable gene at developmental stages and GAPDH is the most stable in different tissues. While 18S rRNA expression during development is differentially regulated, which indicates it is suitable as an internal control for gene expression normalization at the developmental level. Overall, the data suggest that the two most stable housekeeping genes are enough to accurately calibrate gene expression in S. chuatsi. The significance of this study provided convincing references and methodology for housekeeping gene selection and normalization in gene expression analysis with regular PCR or qPCR.

Analysis of Seed-specificity of Silencing fad_2 Gene Expression in Transgenic Rapeseed Line W-4(Brassica napus L.)

This study was to investigate the efficiency and specificity of RNAi silencing on the expression of endogenous fad2 gene in transgenic line W-4. [Method] The relative expression of fad2 gene in seeds at different developmental stages of 7th, 14th, 21st and 28th day after flowering （DAF） as wel as the root, stem, leaf at winter seedling stages of both the transgenic line W-4 and non-transgenic control Westar by real-time fluorescence quantitative PCR. [Results] The results showed the relative expression of fad2 gene was gradual y increasing with the days after flowering in the seeds of the control Westar, while it was found decreasing significantly since the 21st DAF in the seeds of the line W-4. The decline was up to 60% in comparison with the control Westar. However, no significant difference in the relative expression of fad2 gene in other organs like root, stem and leaf was observed between transgenic line W-4 and non-transgenic control Westar. Fatty acid composition analysis showed the oleic acid desaturation parameter（ODP） in seeds of the line W-4 was 0.07 in average, decreased by nearly 75% than control Westar which was 0.24 in average, while no significant difference in the seedling root, stem and leaf was measured between transgenic rapeseed and control. [Conclusion] The results above validated that RNA interference in transgenic rapeseed W-4 is at a seed-specific manner, not interfering with fad2 gene expression in organs such as the root, stem and leaf. The study also found that the period of fad2 gene expres-sion decline was wel coincided with the expression of napin gene, both appeared at the 21st DAF, indicating that the expression of dsRNA of fad2 gene is precisely control ed by the napin promoter.

Overexpression of IGF2R and IGF1R mRNA in SCNT-produced Goats Survived to Adulthood

The procedure of somatic cell nuclear transfer （SCNT） is likely to affect the expression level of growth-related genes especially imprinting genes. In this study, expressions of growth-related genes including three imprinting genes （H19, IGF2, and IGF2R） and four non-imprinting genes （IGF1, IGFIR, GHR, and GHSR） in adult nuclear transferred （NT） goats were investigated by real-time PCR. The expressions of these genes in adult clones were found largely normal, but IGF2R and IGFIR were more highly expressed in cloned goats than in non-NT goats （P 〈 0.01）. Analysis on mono-allelic expression pattern of imprinting genes indicated that mono-allelic expression patterns of H19 and IGF2 in cloned goats were similar to that in non-NT goats. In addition, the sequence of goat IGF2 gene and the putative amino acid sequence were obtained. The 986 nucleotide cDNA of goat IGF2 gene contained an open-reading frame of 540 nucleotides coding for 179 amino acids. Both cDNA sequence and amino acid sequence of IGF2 in goat showed their higher homology with that in sheep than in cattle; the partial cDNA fragments of H19, IGF2R, GHSR, IGFIR, and GHR in goat were also cloned and sequenced, which shared higher sequence identities with those in sheep than in cattle.

Quantitative Detection of Osteopontin High Expression in Human and Rat Hepatocellular Carcinoma

Objective： Osteopontin （OPN） is a secreted phosphorylated glycoprotein that is implicated in proliferation and migration of several malignancies including hepatocellular carcinoma （HCC）. In pregent study, human HCC specimens were collected and rat HCC model was chemical-induced to elucidate the expression significance of OPN in HCC progression. Methods： OPN expression was detected quantitatively by real-time reverse transcription polymerase chain reaction （RT-PCR）. Male Sprague-Dawley rats were administrated diethylnitrosamine （DENA） to induce HCC and OPN expression was dynamically assessed. Results： In 69 cases of 103 HCC patients （67%） OPN was highexpressed in HCC tissues than that in adjacent non-tumor liver tissues and in 58 cases of these 69 cases more than 2-fold. OPN expression was significantly different between HCC and adjacent liver tissues （0.53±0.91 vs 0.11±0.28, P〈0.001）. OPN expression was gradually elevated in occurrence and development of rat HCC. Conclusion： OPN was highexpressed in human HCC and gradually elevated in rat HCC progression.

Analysis of Gene Expression of Seven Isoforms of ADP-glucose Pyrophosphorylase in Rice Endosperm under Different Temperature Conditions

[Objective] This study aimed to analyze the effects of temperature on the expression of AGPase isoform genes in rice endosperm during milk stage. [Method] Different temperature treatments （33 and 25 ℃ of daily mean temperature for high and normal temperature treatments, respectively） and the real-time fluorescence quantitative PCR （ FQPCR） were used to analyze the expression patterns of seven isoforms （AGPS1, AGPS2a, AGPS2b, AGPL1, AGPL2, AGPL3 and AGPL4） of ADPglucose pyrophosphorylase （AGPase） which was the key enzyme in starch synthesis and metabolism in rice endosperm of two rice varieties Teqing and Thai Fragrant Rice. [Result] The AGPase isoforms AGPS2b, AGPL2 and AGPL3 had much higher expression than the other four isoforms, thus they were thought to be the main expression patterns of AGPase in rice endosperm. The relative expressions of AGPL2 was the highest among all the isoforms. The relative expressions of AGPS2b, AGPL2 and AGPL3 were higher in the normal temperature treatment than in the high temperature treatment in both rice varieties. The relative expression of the three enzyme genes in milk stages in Teqing was higher than those in Thai Fragrant Rice under different temperature treatments. [Conclusion] This study provides a theoretical basis for further use of molecular biology techniques to cultivate stable high-quality rice varieties.

基于RTEX总线的H型钢火焰切割机控制系统的设计与应用

针对H型钢手动切割效率低、切割质量不高、人力需求大的缺点,提出并分析了一种H型钢火焰切割机的基本原理,设计了基于RTEX总线的控制系统,采用:PMAC多轴运动控制卡与松下RTEX总线控制,大大提高了加工效率,改善了切割质量,简化了系统布线,提高了设备稳定性与可靠性。

Enhancement of NH_4^+ Uptake by NO_3^- in Relation to Expression of Nitrate-Induced Genes in Rice (Oryza sativa) Roots

This study aimed to survey the expression of genes involved in rice N uptake and aasimilatory network and to understand the potential molecular mechanisms responsible for the NO3^-enhanced NH4^＋ uptake. By using quantitative real-time polymerase chain reaction （PCR）, the genes related to N nutrition, including ammonium transporters （AMTs） and ammonium assimilatory enzymes （GS and GOGAT）, were transcriptionally analyzed in rice plants grown in the absence and presence of NO4^- in the NH4^＋-containing medium. The results showed that NH4^＋ uptake by rice was enhanced by the NO3^- supply to the medium. At the same time and in parallel, the amount of transcripts of seven genes （OsAMT1;1, OsAMT1;2, OsAMT4;1, OsGLNP, OsGLU1, OsGLT1, and OsGLTP） was increased in rice roots, but the expression of two genes （OsGLN1;1 and OsGLN1;P） was decreased and that of OsAMT1;3 remained without change. Up- or downregulation of these genes involved in NH4^＋ uptake and assimilation correlated with the increase in NH4^＋ uptake in the presence of NO3^- in rice roots.

Study on the Expression Laws and Regulatory Functions of miRNA-181b in the Anterior Pituitary of Cattle

[Objective] The research aimed to discuss the differential expression quantity of miRNA-181b in mature（18-month-old） and immature（one-month-old） cattle＇s anterior pituitary and its regulation function.[Method] cDNA library of miRNA in mature（18-month-old） and immature（one-month-old） cattle＇s anterior pituitary were established.After Solexa high-throughput sequencing of miRNA in the cDNA library,miRNA in anterior pituitary of bulls was identified.miRNA-181b with differential expression were selected from the sequencing results.By real-time quantitative RT-PCR,the expression laws of miRNA-181b in the anterior pituitary of Yanbian Cattle in different growth period was validated.And the target genes of miRNA-181b were forecast by using TargetScanS prediction software.[Result] The expression quantity of miRNA-181b had great difference in cattle＇s anterior pituitary different growth periods.The expression quantity of miRNA-181b in anterior pituitary of one-month-old cattle was 4.05 times as that in 18-month-old cattle.The binding of miRNA-181b with 838-844 bases in 3＇ untranslated region of FSHβ gene was specific and the binding base sites were UGAAUGUA.[Conclusion] This research provided the theoretical basis for the transcription regulation research of FSHβ.

Effects of Wei Chang An on expression of multiple genes in human gastric cancer grafted onto nude mice

AIM： To investigate the expression of multiple genes in Chinese jianpi herbal recipe Wei Chang An （WCA） in human gastric cancer cell line SGC-7901. METHODS： A human gastric adenocarcinoma cell line SGC-7902 grafted onto nude mice was used as the animal model. The mice were randomly divided into 3 groups, one control and the two representing experimental conditions. Animals in the two experimental groups received either WCA over a 34-d period or 5-fluorouracil （5-FU） over 6-d period starting at 8th d after grafting. Control animals received saline on an identical schedule. Animals were killed 41 d after being grafted. The expression profiles in paired WCA treated gastric cancer samples and the N.S. control samples were studied by using a cDNA array representing 14181 cDNA clusters. The alterations in gene expression levels were confirmed by Real-time Quantitative polymerase chain reaction （qPCR）. RESULTS： When compared with controls, the average tumor inhibitory rate in WCA group was 44.32% ± 5.67% and 5-FU 47.04% ± 22.33% （P 〈 0.01, respectively）. The average labeling index （LI） for PCNA in WCA group and 5-FU group was significantly decreased compared with the control group. Apoptotic index （AI） was significantly increased to 9.72% ± 4.52% using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate fluorescence nick end labeling （TUNEL） method in WCA group compared with the controls 2.45% ± 2.37%. 5-FU group was also found to have a significantly increased AI compared with the controls. The expression of cleaved Caspase-3 in WCA group and 5-FU group was significantly increased compared with the control group respectively. There were 45 different expressed sequence tags （ESTs） among the control sample pool and WCA sample pool. There were 24 ESTs up-regulated in WCA samples and 21 ESTs down-regulated. By using qPCR, the expression level of Stat3, rap2 interacting protein x （RIPX）, regulator of differentiation 1 （ROD1） and Bcl-2 was lower in WCA group than that in control group respectively. By using SP immunohistochemical method the expression of Phospho-Stat3 （Tyr705） and Bcl-2 in WCA group and 5-FU group was significantly decreased compared with the control group respectively. CONCLUSION： WCA could inhibit gastric cancer cell SGC-7901 growth in vivo. WCA could induce gastric cancer cell apoptosis and suppress proliferation. Its mechanisms might be involved in the down-regulation of Star3, RIPX, ROD1 and Bcl-2 gene.

Identification of differently expressed genes in human colorectal adenocarcinoma

AIM： To investigate the differently expressed genes in human colorectal adenocarcinorna.METHODS： The integrated approach for gene expression profiling that couples suppression subtractive hybridization, high-throughput cDNA array, sequencing, bioinformatics analysis, and reverse transcriptase real- time quantitative polymerase chain reaction （PCR） was carried out. A set of cDNA clones including 1260 SSH inserts amplified by PCR was arrayed using robotic printing. The cDNA arrays were hybridized with florescent-labeled probes prepared from RNA of human colorectal adenocarcinoma （HCRAC） and normal colorectal tissues.RESULTS： A total of 86 genes were identified, 16 unknown genes and 70 known genes. The transcription factor Sox9 influencing cell differentiation was downregulated. At the same time, Heat shock protein 10 KDis downregulated and Calmoulin is up-regulated.CONCLUSION： Downregulation of heat shock protein 10 KD lost its inhibition of Ras, and men attenuated the Ras GTPase signaling pathway, increased cell proliferation and inhibited cell apoptosis. Down-regulated transcription factor Sox9 influences cell differentiation and cell-specific gene expression. Down-regulated Sox9 also decreases its binding to calmodulin, accumulates calmodulin as receptor-activated kinase and phosphorylase kinase due to the activation of PhK.

Down-Regulated Expression of RACK1 Gene by RNA Interference Enhances Drought Tolerance in Rice

The receptor for activated C-kinase 1 （RACK1） is a highly conserved scaffold protein with versatile functions, and plays important roles in the regulation of plant growth and development. Transgenic rice plants, in which the expression of RACK1 gene was inhibited by RNA interference （RNAi）, were studied to elucidate the possible functions of RACK1 in responses to drought stress in rice. Real-time PCR analysis showed that the expression of RACK1 in transgenic rice plants was inhibited by more than 50%. The tolerance to drought stress of the transgenic rice plants was higher as compared with the non-transgenic rice plants. The peroxidation of membrane and the production of malondialdehyde were significantly lower and the superoxide dismutase activity in transgenic rice plants was significantly higher than those in non-trangenic rice plants It is suggested that RACK1 negatively regulated the redox system-related tolerance to drought stress of rice plants.

Molecular cloning and mRNA expression analysis of myosin heavy chain(MyHC)from fast skeletal muscle of grass carp,Ctenopharyngodon idella

The myosin heavy chain(MyHC)is one of the major structural and contracting proteins of muscle.We have isolated the cDNA clone encoding MyHC of the grass carp,Ctenopharyngodon idella. The sequence comprises 5 934 bp,including a 5 814 bp open reading frame encoding an amino acid sequence of 1 937 residues.The deduced amino acid sequence showed 69%homology to rabbit fast skeletal MyHC and 73%–76%homology to the MyHCs from the mandarin fish,walleye pollack,white croaker,chum salmon,and carp.The putative sequences of subfragment-1 and the light meromyosin region showed 61.4%–80%homology to the corresponding regions of other fish MyHCs.The tissue-specific and developmental stage-specific expressions of the MyHC gene were analyzed by quantitative real-time PCR.The MyHC gene showed the highest expression in the muscles compared with the kidney,spleen and intestine.Developmentally,there was a gradual increase in MyHC mRNA expression from the neural formation stage to the tail bud stage.The highest expression was detected in hatching larva.Our work on the MyHC gene from the grass carp has provided useful information for fish molecular biology and fish genomics.

Identification of Sheep Endogenous Beta-Retroviruses with Uterus-Specific Expression in the Pregnant Mongolian Ewe

The sheep genome harbours approximately 20 copies of endogenous beta-retroviruses （enJSRVs）, and circumstantial evidence suggests that enJSRVs might play a role in mammalian reproduction, particularly placental morphogenesis. This study was aimed to assess the expression of mRNAs of an enJSRV and its receptor, HYAL2, in the uterus and conceptuses of Mongolian ewes throughout gestation, using real-time reverse transcription polymerase chain reaction and in situ hybridization analysis. The results showed that enJSRV and HYAL2 mRNAs were found to be expressed throughout gestation in the endometrium, chorion, placenta, and conceptus. The enJSRV mRNA was most abundant in the placenta on day 90 of pregnancy, in the endometrium on day 30 and 50, and in the chorion on day 70 and 110. However, HYAL2 mRNA was most abundant in the endometrium on day 30. These differences were all significantly different from each other （P〈0.01）. In situ hybridization showed that enJSRV and HYAL2 mRNAs were specifically expressed in endometrial luminal epithelium and glandular epithelium, trophoblastic giant binucleated cells （BNCs）, endometrial caruncles, placental cotyledons, stroma, trophectoderm, as well as multinucleated syncytia of the placenta and blood vessel endothelial cells. Collectively, little is known about the molecular mechanisms by which trophoblastic differentiation and multinucleated syncytia formation are regulated by enJSRVs. However, the temporal and spatial distributions of enJSRV expression in the uterus and conceptus indicate that differentiation of BNCs and the formation of a multinucleated syncytiotrophoblast involve enJSRV and possibly its cellular receptor, HYAL2. Therefore, enJSRV and HYAL2 appear to play important roles in the female reproductive physiology in this breed of sheep.