• Molecules and Cells
• /
• v.37 no.4
• /
• pp.302-306
• /
• 2014

Myostatin represses muscle growth by negatively regulating the number and size of muscle fibers. Myostatin loss-of-function can result in the double-muscling phenotype and increased muscle mass. Thus, knockout of myostatin gene could improve the quality of meat from mammals. In the present study, zinc finger nucleases, a useful tool for generating gene knockout animals, were designed to target exon 1 of the myostatin gene. The designed ZFNs were introduced into porcine primary fibroblasts and early implantation embryos via electroporation and microinjection, respectively. Mutations around the ZFNs target site were detected in both primary fibroblasts and blastocysts. The proportion of mutant fibroblast cells and blastocyst was 4.81% and 5.31%, respectively. Thus, ZFNs can be used to knockout myostatin in porcine primary fibroblasts and early implantation embryos.

• Food Science and Biotechnology
• /
• v.18 no.4
• /
• pp.978-984
• /
• 2009

An analytical method for the simultaneous determination of 9 quinolones (QNs) in porcine, chicken, and bovine muscles was developed and validated using liquid chromatography-fluorescence detector (LC-FLD). The samples were extracted using a liquid-liquid extraction (LLE) process. Chromatographic separation was achieved on a reverse phase $C_8$ column with a gradient elution using a mobile phase of 200 mM ammonium acetate buffer (pH 4.5) and acetonitrile (ACN). The proposed method was validated according to the Food and Drug Administration (FDA) guideline for bioanalytical assay procedures. Recoveries of QNs were 83.1-111.9% with relative standard deviations (RSDs) below 15%. Linearity within a range of 30-500 ${\mu}g/kg$ was obtained with the correlation coefficient ($R^2$) of 0.9967-0.9999. The limits of detection (LOD) were 1-16 ${\mu}g/kg$. These values were lower than the maximum residues limits (MRLs) established by the European Union (EU). The present method was successfully applied to determine QNs in edible muscles.

• Food Science of Animal Resources
• /
• v.42 no.5
• /
• pp.874-888
• /
• 2022

This study aimed to compare the similarities, physicochemical properties, and muscle fiber characteristics of porcine skeletal muscles. Fourteen types of muscles were collected from nine pig carcasses at 24 h post-mortem and classified by muscle architecture into two main groups, namely parallel and pennate. The muscles were further differentiated into three subtypes per group. These included fan-shaped, fusiform, and strap for the parallel group, and unipennate, bipennate, and multipennate for the pennate group. Parallel-fibered muscles, which were composed of larger I, IIA, IIX, and IIXB fibers and a lower density of IIA fibers, showed higher redness and yellowness values than pennate-fibered muscles (p<0.05). However, the relative fiber area was not significantly different between the parallel and pennate groups (p>0.05). In the subtypes of parallel architecture, the strap group showed lower moisture content and higher redness values than the other subtypes and had considerably higher amounts of oxidative fibers (I and IIA; 72.3%) than the fan-shaped and fusiform groups (p<0.05). In the pennate group, unipennate showed comparatively lower moisture content and higher lightness than other pennate subtypes and was composed of smaller I, IIA, and IIX fibers than the bipennate and multipennate groups (p<0.05). Finally, a different trend of muscle clustering by hierarchical cluster analysis was found between physicochemical properties and muscle fiber characteristics. These results suggest that the physicochemical properties and muscle fiber characteristics of porcine skeletal muscles are not significantly dependent on morphological properties but are rather related to the intrinsic properties of the individual muscles.

• Korean Journal of Veterinary Research
• /
• v.60 no.4
• /
• pp.209-213
• /
• 2020

This study examined the residue of dl-methylephedrine hydrochloride (MEP) on the muscle of pigs administered orally with MEP 12 g/ton feed for seven consecutive days. Twenty healthy cross swine were administered MEP. Four treated animals were selected arbitrarily to be sacrificed at 1, 2, 3, 4, and 5 days after treatment. MEP residue concentrations in the muscle were determined by liquid chromatography coupled with tandem mass spectrometry. The drug was extracted from muscle samples using 10 mM ammonium formate in acetonitrile followed by clean-up with n-hexane. The analyte was separated on an XBridgeTM hydrophilic interaction liquid chromatography column using 10 mM ammonium formate in deionized distilled water and acetonitrile. The correlation coefficient (R2) of the calibration curve was 0.9974, and the limits of detection and quantification were 0.05 and 0.15 ㎍/kg, respectively. The recoveries at three spiking levels were 94.5-101.2%, and the relative Standard Deviations was less than 4.06%. In the MEP-treated group, MEP residues on one day post-treatment were below the maximum residue limit in the muscle. The developed method is sensitive and reliable for the detection of MEP in porcine muscle tissues. Furthermore, it exhibits low quantification limits for animal-derived food products destined for human consumption.

• Korean Journal of Food Science and Technology
• /
• v.23 no.1
• /
• pp.6-14
• /
• 1991

Intramuscular lipid of longissimus dorsi muscle(white muscle), soleus muscle(red muscle) and cardiac muscle were autooxidized at $37^{\circ}C$ for 20 days, and the rancidity development and the effect of various factors on rancidity development were compared. Although the myoglobin content of red muscle was about 5 times as high as that of white muscle, the degree of autooxidation occurred in intramuscular lipid did not differ between red muscle and white muscle, when they had the same lipid content. Accordingly, it was suggested that the susceptibility of muscle tissues to lipid oxidation depends mainly on the lipid content of muscle tissue, regardless of muscle types. Lipid oxidation was not a major quality deterioration for dried-pork product, when it contained adequate amount of sodium nitrite and was air-tight vacuum-packed.

• Asian-Australasian Journal of Animal Sciences
• /
• v.23 no.5
• /
• pp.640-648
• /
• 2010

Insulin-responsive glucose transporter 4 (GLUT4) is a member of the glucose transporter family and mainly presents in skeletal muscle and adipose tissue. To clarify the molecular structure of porcine GLUT4, RACE was used to clone its cDNA. Several cDNA clones corresponding to different regions of GLUT4 were obtained by amplifying reverse-transcriptase products of total RNA extracted from Landrace porcine skeletal muscles. Nucleotide sequence analysis of the cDNA clones revealed that porcine GLUT4 cDNA was composed of 2,491 base pairs with a coding region of 509 amino acids. The deduced amino acid sequence was over 90% identical to human, rabbit and cattle GLUT4. The tissue distribution of GLUT4 was also examined by Real-time RT-PCR. The mRNA expression abundance of GLUT4 was heart>liver, skeletal muscle and brain>lung, kidney and intestine. The developmental expression of GLUT4 and insulin receptor (IR) was also examined by Real-time RT-PCR using total RNA extracted from longissimus dorsi (LM), semimembranosus (SM), and semitendinosus (SD) muscle of Landrace at the age of 1, 7, 30, 60 and 90 d. It was shown that there was significant difference in the mRNA expression level of GLUT4 in skeletal muscles of Landrace at different ages (p<0.05). The mRNA expression level of IR also showed significant difference at different ages (p<0.05). The developmental change in the mRNA expression abundance of GLUT4 was similar to that in IR, and both showed a higher level at birth and 30 d than at other ages. However, there was no significant tissue difference in the mRNA expression of GLUT4 or IR (p>0.05). These results showed that the nucleotide sequence of the cDNA clones was highly identical with human, rabbit and cattle GLUT4 and the developmental change of GLUT4 mRNA in skeletal muscles was similar to that of IR, suggesting that porcine GLUT4 might be an insulin-responsive glucose transporter. Moreover, the tissue distribution of GLUT4 mRNA showed that GLUT4 might be an important nutritional transporter in porcine skeletal muscles.

• Journal of Animal Science and Technology
• /
• v.64 no.6
• /
• pp.1132-1143
• /
• 2022

Insects are a valuable natural source that can produce a variety of bioactive compounds due to their increasing species diversity. CopA3 is an antimicrobial peptide derived from Copris tripartitus (i.e., the dung beetle). It is known to increase the proliferation of colonic epithelial and neuronal stem cells by regulating cell cycle. This research hypothesized that CopA3 can promote the proliferation of porcine muscle satellite cells (MSCs). The effects of CopA3 on porcine MSCs, which are important for muscle growth and regeneration, remain unclear. Here, we investigated the effects of CopA3 on porcine MSCs. According to viability results, we designed four groups: control (without CopA3) and three treatment groups (treated with 5,10, and 25 ㎍/mL of CopA3). At a CopA3 concentration of 5 ㎍/mL and 10 ㎍/mL, the proliferation of MSCs increased more than that observed in the control group. Furthermore, compared to that in the control, CopA3 treatment increased the S phase but decreased the G0/G1 phase ratio. Additionally, early and late apoptotic cells were found to be decreased in the 5 ㎍/mL group. The expressions of the myogenesis-related transcription factor PAX7 and MYOD proteins were significantly upregulated in the 5 ㎍/mL and 10 ㎍/mL groups, whereas the MYOG protein remained undetected in all group. This study suggested that CopA3 promotes muscle cell proliferation by regulating the cell cycle of MSCs and can regulate the activity of MSCs by increasing the expressions of PAX7 and MYOD.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.9
• /
• pp.1349-1353
• /
• 2007

Calcineurin is a calmodulin dependent protein that functions as a regulator of muscle cell growth and function. Agents capable of interacting with calcineurin could have important applications in muscle disease treatment as well as in the improvement of livestock production. Calsarcins comprise a family of muscle-specific calcineurin binding proteins which play an important role in modulating the function of calcineurin in muscle cells. Recently, we described the first two members of the calsarcin family (calsarcin-1 and calsarcin-2) in the pig. Here, we characterized the third member of the calsarcin family, calsarcin-3, which is also expressed specifically in skeletal muscle. However, unlike calsarcin-1 and calsarcin-2, the calsarcin-3 mRNA expression in skeletal muscle kept rising throughout the prenatal and postnatal development periods. In addition, radiation hybrid mapping indicated that porcine calsarcin-3 mapped to the distal end of the q arm of pig chromosome 2 (SSC2). A C/T single nucleotide polymorphism site in exon 5 was genotyped using the denaturing high performance liquid chromatography (DHPLC) method and the allele frequencies at this locus were significantly different among breeds.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.3
• /
• pp.417-424
• /
• 2003

Inhibitory activities against angiotensin I-converting enzyme (ACE) of enzymatic hydrolysates of porcine skeletal muscle proteins were investigated. Myosin B, myosin, actin, tropomyosin, troponin and water-soluble proteins extracted from pork loin were digested by eight kinds of proteases, including pepsin, $\alpha$-chymotrypsin, and trypsin. After digestion, hydrolysates produced from all proteins showed ACE inhibitory activities, and the peptic hydrolysate showed the strongest activity. In the case of myosin B, the molar concentration of peptic hydrolysate required to inhibit 50% of the activity increased gradually as digestion proceeded. The hydrolysates produced by sequential digestion with pepsin and $\alpha$-chymotrypsin, pepsin and trypsin or pepsin and pancreatin showed weaker activities than those by pepsin alone, suggesting that ACE inhibitory peptides from peptic digestion might lose their active sequences after digestion by the second protease. However, the hydrolysates produced by sequential digestion showed stronger activities than those by $\alpha$-chymotrypsin, trypsin or pancreatin alone. These results suggested that the hydrolysates of porcine meat were able to show ACE inhibitory activity, even if they were digested in vivo, and that pork might be a useful source of physiologically functional factors.

• Journal of Animal Reproduction and Biotechnology
• /
• v.35 no.1
• /
• pp.12-20
• /
• 2020

Cell adhesion plays an important role in the differentiation of the morphogenesis and the trophectoderm epithelium of the blastocyst. In the porcine embryo, CDH1 mediated adhesion initiates at compaction before blastocyst formation, regulated post-translationally via protein kinase C and other signaling molecules. Here we focus on muscle RAS oncogene homolog (M-RAS), which is the closest relative to the RAS related proteins and shares most regulatory and effector interactions. To characterize the effects of M-RAS on embryo compaction, we used gain- and loss-of-function strategies in porcine embryos, in which M-RAS gene structure and protein sequence are conserved. We showed that knockdown of M-RAS in zygotes reduced embryo development abilities and CDH1 expression. Moreover, the phosphorylation of ERK was also decreased in M-RAS KD embryos. Overexpression of M-RAS allows M-RAS KD embryos to rescue the embryo compaction and blastocyst formation. Collectively, these results highlight novel conserved and multiple effects of M-RAS during porcine embryo development.