Microarray profiling for differential gene expression in PMSG-hCG stimulated preovulatory ovarian follicles of Chinese Taihu and Large White sows

<p>Abstract</p> <p>Background</p> <p>The Chinese Taihu is one of the most prolific pig breeds in the world, which farrows at least five more piglets per litter than Western pig breeds partly due to a greater ovulation rate. Variation of ovulation rate maybe associated with the differences in the transcriptome of Chinese Taihu and Large White ovaries. In order to understand the molecular basis of the greater ovulation rate of Chinese Taihu sows, expression profiling experiments were conducted to identify differentially expressed genes in ovarian follicles at the preovulatory stage of a PMSG-hCG stimulated estrous cycle from 3 Chinese Taihu and 3 Large White cycling sows by using the Affymetrix Porcine Genechip™.</p> <p>Results</p> <p>One hundred and thirty-three differentially expressed genes were identified between Chinese Taihu and Large White sows by using Affymetrix porcine GeneChip (<it>p </it>≤ 0.05, Fold change ≥ 2 or ≤ 0.5). Gene Ontology (GO) analysis revealed that these genes belonged to the class of genes that participated in regulation of cellular process, regulation of biological process, biological regulation, developmental process, cell communication and signal transduction and so on. Significant differential expression of 6 genes including <it>WNT10B </it>and <it>DKK2 </it>in the WNT signaling pathway was detected. Real-time RT-PCR confirmed the expression pattern in seven of eight selected genes. A search of chromosomal location revealed that 92 differentially expressed transcripts located to the intervals of quantitative trait loci (QTLs) for reproduction traits. Furthermore, SNPs of two differentially expressed genes- <it>BAX </it>and <it>BMPR1B </it>were showed to be associated with litter size traits in Large White pigs and Chinese DIV line pigs (<it>p </it>≤ 0.1 or <it>p </it>≤ 0.05).</p> <p>Conclusions</p> <p>Our study detected many genes that showed differential expression between ovary follicles of two divergent breeds of pigs. Genes involved with regulation of cellular process, regulation of biological process, in addition to several genes not previously associated with ovarian physiology or with unknown function, were differentially expressed between two breeds. The suggestive or significant associations of <it>BAX </it>and <it>BMPR1B </it>gene with litter size indicated these genetic markers had the potentials to be used in pig industry after further validation of their genetic effects. Taken together, this study reveals many potential avenues of investigation for seeking new insights into ovarian physiology and the genetic control of reproduction.</p

Correlation of Meat pH and Muscle Fiber Characteristics, Cortisol Level, and Tenascin C Gene Expression in Pigs

The effects of meat pH on muscle fiber characteristics, cortisol level, and Tenascin C (TNC) gene expression were examined. The muscle samples (n=100) were randomly collected from the Longissimus thoracis et lumborum (LTL) to determine meat pH at 24 hours (meat pH24h) post-mortem. Muscle samples (five samples per group) with divergent meat pH levels (low versus high) were selected to study muscle fiber characteristics and mRNA expression based on quantitative real-time polymerase chain reaction (qRT-PCR). Blood samples (five samples per group) of the two meat pH levels were taken for serum cortisol analysis. The results showed that there was no significant differences between the groups for the muscle fiber characteristics of total number of fibers, muscle fiber diameter, cross-section area, perimysium thickness, and endomysium thickness. Different meat pH24h values did not affect the cortisol level. The mRNA expression of the TNC gene was significantly (p<0.05) downregulated in the low meat pH24h group compared to the high meat pH24h group. In conclusion, meat pH24h was unrelated to the cortisol level and muscle fiber characteristics. However, the TNC gene might play a role in meat pH24h in pigs

Quality Factor for Low Doses of High-LET Radiations

The International Commission on Radiological Protection (ICRP77) and the International Commision on Radiation Units and Measurements (ICRU70) have recommended that the evaluation of radiation hazards be based on the “dose equivalent” defined as the product of the absorbed dose and some modifying factors, the most important of which is the quality factor (Q). The quality factor is intended to allow for the effect on the resulting detriment of the microscopic distribution of the absorbed energy. It is therefore defined as a function of the collision stopping power (L∞) in water at the point of interest. Thus Q rises monotonically with increasing LET until 175 keV/μm where it achieves a value of 20 and remains at 20 for all higher values of LET

Chromosomal assignment of porcine oncogenic and apoptopic genes CACNA2D2, TUSC4, ATP2A1, COL1A1, TAC1, BAK1 and CASP9

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Association and expression study of MMP3, TGFβ1 and COL10A1 as candidate genes for leg weakness-related traits in pigs

The present study was aimed to determine the association between metalloproteinase 3 (MMP3), transforming growth factor beta 1 (TGFβ1) and collagen type X alpha I (COL10A1) gene polymorphisms with traits related to leg weakness in pigs. Three hundred Duroc × Pietrain cross breds (DuPi) and 299 pigs of a commercial population (CP) were used for the experiment. DuPi animals were examined for 10 different traits describing leg and feet structure, osteochondrosis (OC) scores and bone density status. Data of OC score at condylus medialis humeri, condylus medialis femoris and distal epiphysis ulna regions of CP were used for association analysis. Significant association (P T) with OC at head of femur and bone mineral density in the DuPi population. Association (P A) with rear leg score and the principle component denoting both OC and feet and leg scores in the DuPi population. No association was found between COL10A1 (g.72 C>T) and leg weakness related traits. The associations of SNPs with OC traits could not be confirmed in the commercial population. Expression analysis of the three candidate genes was performed to compare between healthy and OC. TGFβ1 was found to be highly expressed (P < 0.05) in the OC compared to healthy cartilages, but no significant different expressions were observed for MMP3 and COL10A1 genes. The present finding suggested that TGFβ1 and MMP3 genes variants have an effect on some of the leg weakness related traits