• Journal of fish pathology
• /
• v.35 no.2
• /
• pp.167-176
• /
• 2022

We injected infectious myonecrosis virus (IMNV) to pacific whiteleg shrimp, Litopenaeus vannamei, and observed closely with using light microscope and transmission electron microscope (TEM) for 4-8 days post infection (dpi). As clinical signs, abdominal bodies had mild opaque muscles at 5 dpi. And the mortality was shown at 6 dpi. At 8 dpi, most injected shrimps had severe opaque muscles and humped back that cause of movement disorder. As results of histopathological examinations, local parts of abdominal body muscle had muscle fiber hyalinization, muscle fiber atrophy, rounded muscle fibers, myofibrillar hypertrophy in size, a decrease in number of myofibrils and phagocytosis from the sarcolemmas by multiple hemocytes at 4 dpi. Especially, myofibrillar hypertrophy appeared at the whole or random part of single muscle fiber not in specific locations like the center or edge of muscle fiber. At 6-7 dpi, multiple muscle necrosis, muscle fiber segmentation, myofibril lysis ap- peared and a few hemocytes were infiltrated at lesions. At 8 dpi, extensive muscle necrosis, multiple myofibril lysis and muscle fiber atrophy were shown, and very few hemocytes were infiltrated. In early stage of infection, local viral myositis with zenker's degeneration were shown. These lesions appeared multiply after the early stage. In late stage of infection, extensive coagulative muscle necrosis appeared with few of inflammatory response such as hemocytes infiltration. The lack of hemocytes infiltration response at the late stage might be disadvantage for Litopenaeus vannamei to defense against IMNV and to recover, because hematocytes (granulocyte, semi-granulocyte) eliminate pathogen and damaged tissues from infection sites and help recover. As results of the TEM observation, IMNVs that had nonenveloped icosahedral capsid which was 30-40 nm diameter were in myofibril and beside tubules of sarcoplasmic reticulum and moved to the certain direction. The micro-tears and micro-trau- mas in myofibrils caused muscle fiber necrosis. And semi-granulocytes engulfed IMNVs to eliminate virus.

• Korean Journal of Food Science and Technology
• /
• v.18 no.6
• /
• pp.443-449
• /
• 1986

In order to investigate the general characteristics of ATPase and ATPase thermostability between porcine white muscle and red muscle, myofibrillar proteins were prepared and compared their physicochemical characteristics. SDS-polyacrylamide gel electrophoretic analyses showed that a protein band of 30,000 daltons was detected noticeably in myofibril from red muscle, but negligibly in myofibril from white muscle. The noticeable differences were found between porcine white muscle and red muscle for the activities of EDTA-ATPase, Ca-ATPase and Mg-ATPase. Myofibrillar proteins from white muscle showed higher thermostability than those from red muscle. Thermodynamic parameters, enthalpy $({\Delta}H^#)$, entropy $({\Delta}S^#)$, etc., showed characteristic variations between porcine white muscle and red muscle.

• Food Science of Animal Resources
• /
• v.29 no.3
• /
• pp.317-324
• /
• 2009

In order to reduce the increased hardness of beef bulgogi due to hydrostatic pressure (HP), kiwifruit (Actinidia chinensis) was applied. To understand the changes of shear force in beef bulgogi with kiwifruit induced by HP, changes in chemical properties of myofibril (Mf) with 10% kiwifruit induced by HP were investigated. From the SDS-PAGE patterns of Mf with 10% kiwifruit, there was an observed increase in the degradation of myosin heavy chain (MHC) by HP (300-500 MPa) to that by 0.1 MPa. This result indicates that HP may enhance enzyme action from a kiwifruit for the degradation of MHC, and the similar phenomenon occurred in the beef bulgogi with kiwifruit induced by HP. The shear force of beef bulgogi without a kiwifruit induced by 400 and 500 MPa significantly increased compared to that by 0.1 MPa (p<0.05). However, in the beef bulgogi with 10% or 20% kiwifruit, the shear force induced by 400 or 500 MPa was similar or slightly lower than that by 0.1 MPa. Consequently, adding kiwifruit to bulgogi could reduce the hardness of HP-induced beef bulgogi due to the enzyme action in the kiwifruit accelerated by HP.

• Asian-Australasian Journal of Animal Sciences
• /
• v.14 no.12
• /
• pp.1763-1768
• /
• 2001

The combined effects of low voltage electrical stimulation (ES) and early short-term temperature conditioning on meat quality of Hanwoo beef (Korean native cattle) during storage were investigated. Shear force was influenced by ES and aging. Combination of ES and the $30^{\circ}C$ conditioning resulted in higher myofibril fragmentation index and improved lightness. There was no substantial difference in drip loss among treatments but ES samples showed higher cooking loss than control. Negative effect on shelf-life was not found by early short-term high temperature conditioning. Therefore, the meat quality of Korean native cattle was effectively improved by the combination of ES and the $30^{\circ}C$ conditioning.

• Biomedical Science Letters
• /
• v.2 no.1
• /
• pp.71-90
• /
• 1996

There is considerable current interest in the effect of regular vigorous exercise and in particular endurance-running as a possible measure in improving myocardial function. Some data indicate that the aging heart may actually suffer from vigorous endurance exercise. On the contrary appropriate exercise in aged animals improves myocardial function and aerobic energy metabolism. So far there is relatively little data to indicate that endurance exercise is in fact beneficial in improving myocardial function or damaging to heart of aged animals. The present investigation aimed to study the possible effect of a long range treadmill training program on the heart in aging rats. Male rats aged 3, 10, and 20 months were divided at random into a control (sedentary) and an exercise group. The training group was exercised for 5 days a week on an automated treadmill for 20minutes at 18m/min over a period of 5 months. The exercise regimen of our experiments did not cause any significant changes in the tissues and ultrastructural as com-pared with sedentary age-matched control. Tissues and ultrastructures of myocardial cells in trained group aged 8 months are intact and well organized as well as sedentary control group. Age associated tissue and ultrastructural changes of trained group aged 15 months included : an increase in transformed mitochondria, vacuoles, lysosomes, lipid droplets and early lipofuscin. But the trained heart did not show significant difference in tissue and ultrastructural properties from those of sedentary controls. Endurance-trained group aged 25 months showed significant qualitative tissue and ultrastructural difference as compared with age-matched controls. In addition to those found in 25 months control group, focal necrosis, myofibril fraying, hypercontraction band, seperation of intercalated discs, degenerating nucleus and infiltration of collagenous fiber into myocyte were noted in trained 25 months group. The stereological examination of the mi-crographs disclosed no significant difference in the myoflbril, mitochondrion, sarcotubule and in-terstitium volume density and surface density of mitochondrial cristae and numerical density of mitochondria between trained and control group aged 8 and 15 months. In the trained 25 months group, significant increase in volume density of interstitium, lipofucsin granule were shown as compared to untrained age-matched control. On the other hand, significant decrease in mitochondrion volume density was shown. The myofibril volume density did not differ between trained and control group although trained group showed slight increase. From the data obtained a reduced mitochondria/myofibrils ratio was found in trained rat heart aged 25 months and there was no difference between trained and control rat aged 15 months. But a slight but not significant increase was found in the trained group aged 8 months as compared with same age control group. Such increase in the ratio in young animals is considered to be of great importance to cardiac pumping and adaptability. Whereas such adaptations don't seem to occur in aged heart muscle. This study proposed that repeated endurance exercise do not cause any significant qualitative and quantitative ultrastructural change of heart muscle in young(3months) and adult (10months) suggesting that the heart is able to adapt to the exercise. On the contrary, the repeated endurance exercise stress may actually induce degenerative changes in the aged heart muscle(20months).

• Korean Journal of Poultry Science
• /
• v.14 no.2
• /
• pp.137-143
• /
• 1987

This study was carried out to compare the changes in the extractability, biological activity, and solubility of myofibrillar proteins and actomyosins during storage period at 4$^{\circ}C$ and -20$^{\circ}C$in pectoral. and leg muscle of broiler meat. 1. The results obtained are as fellows ; The extractabilities of myofibrillar proteins in pectoral and leg muscle were increased gradually to 7-days during storage at 4$^{\circ}C$ and decreased slightly during frozen storage at -20$^{\circ}C$. The extractabilities of actomyosins in pectoral and legmuscle were not greatly changed during cold storage and decreased gradually during frozen storage. 2. The Ca$\^$2+/-ATP ase activities of myofibrillar proteins in the both muscles were not greatly changed to 7-days during cold storage, and in the case of frozen storage, those were highest on the 2nd week, thereafter decreased with storage period. The Ca$\^$2+/-ATPase activities of actomyosins in pectoral and leg muscle were decreased sightly only frist day during cold storage and decreased gently during frozen storage. 3. Myofibrillar proteins in the both muscles were solubilized completely at 0.20M KCl in fresh meat, at 0.25M (pectoral) and 0.30M KCl (leg) in the cold storage, and at 0.30M KCl in the frozen storage. Actomyosins of both muscles were solubilized completely at 0.40M KCl in fresh meat, cold and frozen storage.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.8
• /
• pp.1292-1296
• /
• 2003

The purpose of this study is to investigate the changes of physico-chemical properties of chilled plaice muscle, stored at 4$^{\circ}C$ for 0 ∼ 21 days, with different packaging methods (vacuum packaged with PVDC and aerobic packaged with HDPE). pH value in aerobic packaged plaice muscle (APPM) decreased from 6.3 to 6.09 at first 2 day storage, and then increased gradually during storage time. Although pH pattern of vacuum packaged plaice muscle (VPPM) was similar to that of APPM, change of pH value during storage time was slower and lower than APPM. VBN value in aerobic packaged one increased during storage time. Especially it increased significantly after 7 days of storage. While VBN value in VPPM increased only a little to 14 days. TBA value showed significant difference between APPM and VPPM. WHC of APPM was higher than that of VPPM after 7 days of storage. In electrophoretic pattern of myofibril of APPM stored for 14 days hydrolysis of heavy chain and tropomyosin was observed. However, in VPPM, some hydrolysis occurred only in heavy chain. SDS-PAGE analysis showed that hydrolysis of VPPM occurs later than that of APPM.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.38
• /
• pp.33.1-33.6
• /
• 2016

Background: The purpose of this study was to compare the expression levels of p65 and S100 in the rat masseter muscle after the injection of different concentrations of botulinum toxin-A (BTX-A). Methods: We injected either 5 or 10 U of BTX-A into both masseter muscle of rats. As a control group, the same volume of saline was injected. After 14 days, the animals were sacrificed. Subsequently, a biopsy and immunohistochemical staining of the samples were performed using a p65 or S100 antibody. Results: The cross-sectional area of each myofibril was significantly reduced by BTX-A injection (P < 0.001). The expression of p65 and S100 increased significantly with increasing concentrations of BTX-A (P < 0.001). Conclusions: The injection of BTX-A into the masseter muscle induced muscle atrophy. Subsequently, p65 and S100 expression in myoblasts were increased for the protection of muscle cells.

• Journal of Animal Science and Technology
• /
• v.62 no.4
• /
• pp.533-542
• /
• 2020

The objective of this study was to observe the interactions between salt-soluble proteins extracted from beef and elephant foot yam (Amorphophallus campanulatus) flour in heat-induced gel matrix development. The effect of salt concentration; 0.5%, 1.0%, 1.5%, and 2.0% in weight/weight basis (w/w), during protein extraction on pH, salt-soluble protein concentration and myofibril fractions of beef extract was determined firstly, and no significant effect was found. The beef salt-soluble proteins extracted using salt solution at different concentrations were then added with elephant foot yam flour at 5%, 10%, and 15% w/w, gelatinized at 90℃ for 20 min, and cooled down at 4℃ for 12 h. The interactions between beef salt-soluble proteins and elephant foot yam flour resulted in an improved gel strength (p < 0.01) and the addition level of elephant foot yam flour affected the pH, instrumental color, moisture, crude protein, and ash content significantly. The addition of elephant foot yam flour also reduced the size of the pores in the gel matrix as shown by scanning electron microscope (SEM) photographs. These suggest that elephant foot yam flour well interacts with beef salt-soluble proteins to form gel matrix.

• Food Science of Animal Resources
• /
• v.38 no.5
• /
• pp.1101-1108
• /
• 2018

The aim of this study was to investigate the effects of dry-aging (DA) and the cooking process on the myofibril protein functionalities and in vitro digestibility of proteins in beef loin. Six sirloins from beef were dry-aged for 28 d, and the control group (n=6) was analyzed 2 d postmortem for this study. Dimensional changes (reduction of thickness and surface shrinkage) after cooking were significantly greater in the control group than the DA group, whereas the shear force of the DA group was significantly lower than that of the control. Effect of cooking on aggregation, hydrophobicity, and in vitro digestibility were significantly higher in the DA group than in the control. After cooking, the protein in DA sirloins was more oxidized than in the control samples. According to the sodium dodecyl sulfate-polyacrylamide gel electrophoresis result, the low molecular weight bands (below 17 kDa) increased in the DA group, finding that the protein characteristics of dry-aged beef was affected by cooking.