• Genomics & Informatics
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• v.8 no.2
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• pp.81-85
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• 2010

The aim of the study was to investigate pig reference families, generated from Korean native pigs (KNP) that were crossed with Yorkshire (YS) breeds, which were used to evaluate genetic markers to select breeding animals with superior pork quality. A set of five candidate genes (PRKAG3, MC4R, CAST, ESR, and PRLR ) was analyzed for association with pork quality traits. PRKAG3 (I199V) SNP genotypes were significantly associated with muscle moisture, protein, and fat contents. The MC4R D298N polymorphism was significantly associated with meat tenderness and color traits. The CAST polymorphism was significantly associated with muscle moisture and crude protein traits. These three genes have been associated with pork quality traits in other pig populations, and some of our results are consistent with earlier studies. In addition, two reproductive candidate genes (ESR and PRLR ) did not have significant associations. These results suggest that further study is warranted to investigate and develop more DNA markers associated with pork quality in our KNP-crossed pig families.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.7
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• pp.931-937
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• 2006

The full-length cDNA of the porcine SMPX gene was obtained by the rapid amplification of cDNA ends (RACE). The nucleotide sequences and the predicted protein sequences share high sequence identity with both human and mouse. The promoter of SMPX was sequenced and then analyzed to find the promoter binding sites. The reverse transcriptase-polymerase chain reaction (RT-PCR) revealed that SMPX has a high level of expression in heart and skeletal muscle, a very low expression in lung and spleen and no expression in liver, kidney, fat and brain. Moreover, SMPX has a differential expression level in skeletal muscle, the expression in 65-day embryos being higher than other stages. The porcine SMPX was mapped to SSCXp24 by using a somatic cell hybrid panel (SCHP) and was found closely linked to SW1903 using the radiation hybrid panel IMpRH. An A/G single nucleotide polymorphism (PCR-RFLP) in the 3'-untranslated region (3'-UTR) was detected in eight breeds. The analysis of allele frequency distribution showed that introduced pig breeds (Duroc and Large White) have a higher frequency of allele A while in the Chinese indigenous pig breeds (Qingping pig, Lantang pig, YushanBlack pig, Large Black-White pig, Small Meishan) have a higher frequencies of allele G. The association analysis using an experimental population (188 pigs), which included two cross-bred groups and three pure-blood groups, suggested that the SNP genotype was associated with intramuscular fat content.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.8
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• pp.1084-1094
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• 2019

Objective: The aim of this study was to select the candidate genes affecting meat quality and preliminarily explore the related molecular mechanisms in the Mashen pig. Methods: The present study explored genetic factors affecting meat quality in the Mashen pig using RNA sequencing (RNA-Seq). We sequenced the transcriptomes of 180-day-old Mashen and Large White pigs using longissimus dorsi to select differentially expressed genes (DEGs). Results: The results indicated that a total of 425 genes were differentially expressed between Mashen and Large White pigs. A gene ontology enrichment analysis revealed that DEGs were mainly enriched for biological processes associated with metabolism and muscle development, while a Kyoto encyclopedia of genes and genomes analysis showed that DEGs mainly participated in signaling pathways associated with amino acid metabolism, fatty acid metabolism, and skeletal muscle differentiation. A MCODE analysis of the protein-protein interaction network indicated that the four identified subsets of genes were mainly associated with translational initiation, skeletal muscle differentiation, amino acid metabolism, and oxidative phosphorylation pathways. Conclusion: Based on the analysis results, we selected glutamic-oxaloacetic transaminase 1, malate dehydrogenase 1, pyruvate dehydrogenase 1, pyruvate dehydrogenase kinase 4, and activator protein-1 as candidate genes affecting meat quality in pigs. A discussion of the related molecular mechanisms is provided to offer a theoretical basis for future studies on the improvement of meat quality in pigs.

• Tuberculosis and Respiratory Diseases
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• v.38 no.3
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• pp.270-279
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• 1991

It has been well known that the integrity of airway epithelium is important in developing of bronchial hyperreactivity or bronchial asthma. But the mechanisms underlying this nonspecific airway hyperresponsiveness are not yet determined. To evaluate the ability of guinea pig trachea to release an epithelium derived relaxing factor (EpDRF) which relax rat vascular smooth muscle, we performed the coaxial bioassay using guinea pig trachea and rat aorta. And to evaluate the nature of EpDRF we investigate the influence of methylene blue and indomethacin on the coaxial bioassay. Results were as follows. 1) Vascular smooth muscle mounted into the epithelium intact trachea which was precontracted with phenylephrine was relaxed by addition of histamine or acetylcholine. But vascular smooth muscle mounted into epithelium denuded trachea failed to be relaxed. 2) Epithelium dependent relaxation of vascular smooth muscle was not affected by pretreatment of methylene blue or indomethacin. These results strongly suggests that guinea pig tracheal epithelium releases EpDRF which is able to relax rat vascular smooth muscle. And EpDRF released by airway epithelium is not related to endothelium derived relaxing factor (EDRF) or cyclooxygenase products.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.1
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• pp.125-129
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• 2011

The aim was to determine the relationship between muscle structure and meat quality traits in neuromuscular compartments (NMCs: R1, R2, R3, R4) of pig semitendinosus muscle. Barrows from the INTA-MGC genetic line (Argentina) were slaughtered at 100 kg body weight. In each NMC the following parameters were determined: the fibre types I, IIA, IIX and IIB by immunohistochemistry, the fibre cross sectional area (FCSA), the pH of meat after 24 h post-mortem ($pH_{24}$), instrumental meat tenderness (WB) and colour ($L^*$, $a^*$, $b^*$). There were significant differences in the following: $L^*$ (R1 = R4$a^*$ (R1>R4>R2 = R3), $b^*$ (R1 = R4R1 = R3 = R4), $pH_{24}$ (R1 = R4>R2 = R3). The relative percentages of FCSA were as follows: I (R4>R1>R3>R2), IIA (R1>R4>R3>R2), IIX (R1 = R2 = R3 = R4) and IIB (R2>R3>R1>R4). The correlation values were statistically significant between IIB and WB (R1 and R4, $r_s$ = 0.66), (R2 and R3 $r_s$ = 0.74), IIB and $L^*$ (R1 and R4 $r_s$ = 0.84), IIX and $L^*$ without discriminating NMCs. Our data suggest that the NMC where the sampling takes place is important for determining meat quality traits because of the heterogeneity of the whole muscle.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.10
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• pp.1473-1477
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• 2007

Four-and-a-half LIM-only protein 3 (FHL3) is a member of the LIM protein superfamily and can participate in mediating protein-protein interaction by binding one another through their LIM domains. In this study, the 5'- and 3'- cDNA ends were characterized by RACE (Rapid Amplification of the cDNA Ends) methodology in combination with in silico cloning based on the partial cDNA sequence obtained. Bioinformatics analysis showed FHL3 protein contained four LIM domains and four LIM zinc-binding domains. In silico mapping assigned this gene to the gene cluster MTF1-INPP5B-SF3A3-FHL3-CGI-94 on pig chromosome 6 where several QTL affecting intramuscular fat and eye muscle area had previously been identified. Transcription of the FHL3 gene was detected in spleen, liver, kidney, small intestine, skeletal muscle, fat and stomach, with the greatest expression in skeletal muscle. The A/G polymorphism in exon II was significantly associated with birth weight, average daily gain before weaning, drip loss rate, water holding capacity and intramuscular fat in a Landrace-derived pig population. Together, the present study provided the useful information for further studies to determine the roles of FHL3 gene in the regulation of skeletal muscle cell growth and differentiation in pigs.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.3
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• pp.227-234
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• 2000

Many reports suggest that neurotensin (NT) in the gastrointestinal tract may play a possible role as a neurotransmitter, a circulating hormone, or a modulator of motor activity. NT exerts various actions in the intestine; it produces contractile and relaxant responses in intestinal smooth muscle. This study was designed to investigate the effect of NT on motility of antral circular muscle strips in guinea-pig stomach. To assess the role of $Ca^{2+}$ influx in underlying mechanism, slow waves were simultaneously recorded with spontaneous contractions using conventional intracellular microelectrode technique. At the concentration of $10^{-7}$ M, where NT showed maximum response, NT enhanced the magnitude $(863{\pm}198%,\;mean\;SEM,\;n=13)$ and the frequency $(154{\pm}10.3%,\;n=11)$ of spontaneous contractions. NT evoked a slight hyperpolarization of membrane potential, tall and steep slow waves with abortive spikes $(278{\pm}50%,\;n=4).$ These effects were not affected by atropine $(2\;{\mu}M),$ guanethidine $(2\;{\mu}M)$ and tetrodotoxin (0.2μM). NT-induced contractile responses were abolished in $Ca^{2+}-free$ solution and reduced greatly to near abolition by $10\;{\mu}M$ of verapamil or 0.2 mM of $CdCl_2.$ Verapamil attenuated the effects of NT on frequency and amplitude of the slow waves. Taken together, these results indicate that NT enhances contractility in guinea-pig gastric antral circular muscle and $Ca^{2+}$ influx through the voltage-operated $Ca^{2+}$ channel appears to play an important role in the NT-induced contractile mechanism.

• The Korean Journal of Physiology
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• v.22 no.2
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• pp.207-218
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• 1988

Effects of 1, 4-dihydropyridine compounds, such as nifedipine, nisoldipine, nitrendipine, and nimodipine which were calcium antagonists on the normal and Ca-dependent, slow channel mediated action potentials in the guinea pig's papillary muscle were investigated. The glass microelectrode was impaled into a papillary muscle cell for measurements of potential changes with the simultaneous tracing of isometric contraction. The concentration of Ca antagonists were 1 mg/l (nifedipine and nisoldipine), 2 mg/l (nitrendipine and nimodipine), which showed the maximal inhibition of isometric contraction (above 90%) and simultaneous effects on the normal action potentials and only the halves of those concentrations were sufficient to observe the effects on the calcium action potentials. The data for analysis were only chosen when the microelectrode was maintained in a cell throughout the experiments. 1, 4-Dihydropyridine compounds decreased the action potential duration but did not affect the resting membrane potential, overshoot, and upstroke velocity of the normal action potentials with the decrease in the isometric contraction. And with the decrease in the area and amplitude of isometric contraction, the area, amplitude, upstroke velocity and duration of Ca action potential was decreased. But the differences in the effects of the Ca antagonists were not observed. Therefore it is inferred that the changes in normal and Ca action potential induced by the 1, 4-dihydropyridine compounds with a common chemical structure would be caused by the slow inward Ca-current, not by a fast Na-current.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.6
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• pp.479-486
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• 2000

The aim of this study was to clarify the mechanism of the inhibitory action of carbon monoxide (CO) on contraction, by measuring cytosolic $Ca^{2+}$ level $([Ca^{2+}]_i)$ and ionic currents in guinea-pig ileum. CO (10%) inhibited 40 mM KCl-induced contraction and this effect was blocked by ODQ $(1\;{\mu}M),$ a soluble guanylyl cyclase (sGC) inhibitor. CO inhibited the 40 mM KCl-induced contraction without changing $[Ca^{2+}]_i.$ Cumulative addition of KCl induced a graded increase in $[Ca^{2+}]_i$ and muscle tension. In the presence of CO, cumulative addition of KCl induced smaller contraction than in the absence of CO. On the other hand, the increase in $[Ca^{2+}]_i$ induced by cumulative addition of KCl was only slightly decreased in the presence of CO, and the $[Ca^{2+}]_i-tension$ relationship shifted downwards. Using the patch clamp technique with a holding potential of -60 mV, we found that CO had little effect on the peak Ba currents $(I_{Ba})$ when voltage was stepped from -60 mV to 0 mV. In addition, CO showed no effect on the depolarization-activated outward $K^+$ currents in the all potential ranges. We conclude that CO inhibits smooth muscle contraction mainly by decreasing the $Ca^{2+}$ sensitivity of contractile elements via a cGMP-dependent pathway, not by involving L-type $Ca^{2+}$ and outward-potassium currents in guinea-pig ileum.

• Food Science of Animal Resources
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• v.21 no.3
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• pp.183-191
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• 2001

Comparisons between the Korean native pig(KNP: 75kg of slaughter weight and 240 days of age) versus Landrace(110kg of slaughter and 180 days of age) in dressing and lean meat percentages, compositions of fatty acids and amino acids and sensory evaluations on longissimus muscle are as below. Compared with Landrace, KNP had smaller percentages in dressing and lean meat percentages and a smaller backfat thickness. In retail cuts, KNP had greater percentages in shoulder butt, belly and picnic shoulder and smaller percentages in spareribs, ham and loin muscle. The KNP had greater percentages in crude fat, palmitic(C16:0) and linolenic(C18:3) acids and smaller percentages in oleic(C18:1) and linoleic(C18:2) acids, but total cholesterol content and ratios of saturated and unsaturated fatty acids and essential fatty acids did not differ between the two breeds. In amino acid composition, KNP had a greater percentage in lysine, but smaller percentages in most other amino acids. The KNP had a greater a*(redness) value in longissimus muscle(LM) color and a greater L*(whiteness) value in attached backfat color. Moreover, sensory evaluations on cooked LM showed that KNP had greater flavor, tenderness and springiness, which resulted in a greater overall acceptability. In summary, KNP, compared with Landrace, had smaller dressing and lean meat percentages, a smaller backfat thickness, greater percentages in popular retail cuts, greater percentages in intramuscular fat and an $\omega$-3 component linolenic acid, with no difference in cholesterol content, which, altogether, is considered to be more beneficial for human health.