• Asian-Australasian Journal of Animal Sciences
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• 제15권1호
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• pp.111-116
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• 2002

This study investigated quantitative changes in the spaces between and within myofibrils and the impact of high and low voltage electrical stimulation on muscle ultrastructure as seen in electron micrographs. In addition, the relationships of these spaces and the impact to meat tenderness were investigated. The degradation of myofibrils during aging appeared to be localized across the muscle fibre. Structural deterioration of muscle fibres was evident 1 day post-mortem, involving the weakening in the lateral integrity of the myofibrils and Z-disc regions. Meat tenderisation, as shown by objective measurements, coincided with these increases in degradation, as assessed by the sum of the gaps between and within myofibrils. The results showed that the total size of gaps between and within myofibrils can be used as an indicator of meat tenderization during aging, but that ultrastructural alteration in electrically stimulated muscle had little relationship with meat tenderness.

• Applied Microscopy
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• 제28권1호
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• pp.1-19
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• 1998

Ultrastructural study of the development of the atrioventricular (AV) node was studied by electron microscopy in human fetus ranging from 30 mm to 260 mm crown rump length, and compared with human adult. By 30 mm fetus, the right AV nodal primordium was located below the attachment of the right venous valve. The left AV nodal primordium was observed below the attachment of septum primum. The cytoplasm of the nodal primordia contained few mitochondria, and myofibrils. These cells were apposed to each other with occasional desmosomes. In 40 mm fetus, the AV node cells were poorly organized myofibrils, while working myocardial cells were well organized myofibrils with sarcomere. At 70 mm fetus, intercalated discs were developed in the working myocardial cells. At 100 mm fetus, the nodal cells contained a relatively clear cytoplasm with a few groups of myofibrils and mitochondria. By $140\sim200$ mm fetuses, the nodal cells were an increasing number of myofibrils and mitochondria and these were scattered throughout the cytoplasm. At 260 mm fetus, the nodal cells were small and contained a clear cytoplasm with sparse and poorly organized myofibrils and mitochondria. All major ultrastructural features which characterize the adult AV nodal cells were found in this stage. The working myocardial cells were larger and had a more compact cytoarchitecture than nodal cells. Zonula adherens or fasciae adherens type junction were not found between nodal cells, but they frequently observed between nodal and working myocardial cells.

• 한국식품과학회지
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• 제6권2호
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• pp.79-85
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• 1974

근원섬유단백질의 생화학적 성질에 대하여서는 아직도 불명한 점이 많고, 특히 식품으로써의 근원섬유단백질의 저장 중의 변화에 대하여서는 규명되어야 할 점이 너무나 많다. 본 연구는 근원섬유단백질의 저장 중의 변화를 추구하기 위한 기초작업으로서 subcelular structure인 근원섬유를 재료로 하여 그 형태학적 측면과 생화학적 측면의 상관성을 비교 검토하였다. 근원섬유의 조제방법에 따라서 근원섬유의 근절(筋節)(sarcomere)의 길이는 변화하고 있었고 근절의 길이의 변화는 생화학적 성질. 즉 ATPase활성에 현저한 변화를 일으켰다. 근원섬유를 저농도의 trypsin으로 처리하면 근원섬유의 ATPase활성은 현저히 증가하나, 근원섬유의 위상차(位相差)현미경 상은 수축상태의 상을 나타내었다가 처리시간의 연장에 따라 sarcomere가 fragmentation을 나타냄을 보여주었다. 얻어진 결과로 근원섬유 중에는 ATPase활성을 저해하는 factor가 존재하며, 이 factor는 단백질의 inhibitory action은 아니고 steric effect임을 추정하였다. 또한 Z-line의 구성물질 중에 troponin의 관여가 추정되었다.

• 한국축산식품학회지
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• 제18권4호
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• pp.292-300
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• 1998

This study was undertaken to determine the influence in the Z-disk domain of titin on the tenderization of meat by the structure change of myofibrillar Z-disks during post-mortem aging. After weakening the structure of Z-disks, the Z-disk region was splitted. As the results, myofibrils were fragmented by mechanical strength. Using indirect immunofluorescence microscopy, we show that the Z-disk domain of titin was disappeared from myofibrils in this period. There phenomenon were also shown by treating myofibrils with a solution containing 0.1mM $Ca^{2+}$. We conclude that change in Z-disk domain of titin is directly effected on the tenderization of meat during post-mortem aging and these change is due to manily calcium ions.

• 한국축산식품학회지
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• 제32권5호
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• pp.578-583
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• 2012

The purpose of this study was to evaluate the ultrastructural and shear force changes of duck breast and leg meat during aging at $0^{\circ}C$. Pekin ducks (45 d old) purchased from Greemud Co. were used for this experiment, and were stored at $0^{\circ}C$ for 7 d in order to determine the changes of the meat structure using transmission electron microscopy (TEM) and shear force. At day 0, A-band, I-band, M-line and Z-line of sarcomeres were seen clearly, but sarcomeres started to lose structure and become extended in length from day 2. With extended aging periods, myofibrils were destroyed and symptoms of aging became more obvious. In the duck breast meat, some myofibrils were also destroyed at the Z-line, but were mainly destroyed at the M-line. The change in structure of duck leg meat over time was similar to that of breast meat. After five days and seven days of aging, mitochondria size and quantity were determined to be increased between the myofibrils. Shear force was decreased over time. From this study, aging at $0^{\circ}C$ was found to negatively influence the ultrastructure and shear force of duck meat.

• Asian-Australasian Journal of Animal Sciences
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• 제20권6호
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• pp.994-1001
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• 2007

Changes in shear force value, transverse sections, myofibrils and intramuscular connective tissue of bovine skeletal muscle exposed to the combination of high-pressure up to 400 MPa and heat (30 and $60^{\circ}C$) were studied. The shear force value decreased by pressure-heat treatment up to 200 MPa at 30 and $60^{\circ}C$, and then slightly increased over 200 MPa at $30^{\circ}C$. Shear force values of treated muscles were lower than those of untreated ones. Gaps between muscle fibers in the untreated muscle were a little clear, and then they became very clear in the treated muscles up to 200 MPa at 30 and $60^{\circ}C$. However, the gaps reduced significantly over 200 MPa at $30^{\circ}C$. The remarkable rupture of I-band and loss of M-line materials progressed in the myofibrils with increasing pressure applied. However, degradation and loss of the Z-line in myofibrils observed in the muscle treated at $60^{\circ}C$ was not apparent in the muscle treated at $30^{\circ}C$. The length of the sarcomere initially contracted by pressure-heat treatment of 100 MPa at $30^{\circ}C$ seemed to have recovered with increase of the pressure up to 400 MPa. In the muscle treated at $60^{\circ}C$, the length of sarcomere gradually decreased with increase of the pressure up to 400 MPa. In the treated muscles, changes in the honeycomb-like structure of endomysium were observed and accelerated with increase of the pressure. A wavy appearance clearly observed at the inside surface of endomysium in the untreated muscles gradually decreased in the treated muscles with increase of the pressure. Tearing of the membrane was observed in the muscles treated over 150 MPa at $30^{\circ}C$, as observed in the sample pressurized at 100 MPa at $60^{\circ}C$. The roughening, disruption and fraying of the membrane were observed over 200 MPa at $60^{\circ}C$. From the results obtained, the combination of high-pressure and heat treatments seems to be effective to tenderize tough meat. The shear force value may have some relationship with deformation of intramuscular connective tissue and myofibrils.

• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 1996년도 제17차 정기총회 및 학술발표회 진행표 및 발표논문 초록
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• pp.50-50
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• 1996

• 한국식품영양과학회지
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• 제18권1호
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• pp.123-130
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• 1989

방어로부터 추출한 근원섬유 현탁액을 $0^{\circ}C$(빙장), $-3.5^{\circ}C$(PF저장), $-20^{\circ}C$(동결저장)에 저장하면서 Ca-과 Mg-ATPase활성을 측정하여 근육단백질의 변성을 조사하였으며 일부는 생선을 각 온도에 일정기간 저장한 후 근원섬유를 추출하여 단백질 변성정도를 비교한 결과 추출한 근원섬유를 저장하였을 때 빙장 및 PF저장한 시료의 ATPase활성은 비슷한 수준이었으나 동결 저장한 시료에서는 현저히 낮았다. 생선을 각 온도에 1주일간 저장한 후 추출한 근원섬유의 소활성은 근원섬유를 미리 추출하여 같은 기간동안 저장한 경우에 비하여 빙장과 PF저장에서는 1.2-1.8배, 동결저장에서는 2.5-3배 정도 높은 수준을 유지하고 있었다. 근원섬유를 각 온도에 저장하였을 때의 변성속도는 Ca-의 경우가 Mg-ATPase에 비 해 2-3배 빨랐으나 생선으로 저장한 경우에는 Ca-과 Mg-ATPase간에 큰 차이를 나타내지 않았다.

• Asian-Australasian Journal of Animal Sciences
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• 제15권5호
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• pp.721-724
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• 2002

Postmortem Proteolysis of breast (BM) and leg (LM) muscles in Chiayi native chickens at $5^{\circ}C$ were compared. Myofibrils were purified from BM and LM samples that were randomly taken from carcasses after 0, 1, 3, 7 and 14 days of storage at $5^{\circ}C$. Fragmentation of myofibrils were determined, and degradation of myofibrillar proteins were analyzed by the SDS-PAGE and western blots. The results showed that myofibril fragmentation index (MFI) was significantly (p<0.05) higher in BM than in LM samples. Disappearance of titin and nebulin and appearance of the 30 kDa component were more rapidly as seen on SDS-PAGE in BM than in LM samples. Western blots labeled with a monoclonal antibody to desmin also demonstrated that desmin degraded more quickly in BM samples. Our data suggested that postmortem proteolysis occurred more rapidly in breast muscles in Chiayi native chickens.

• Applied Microscopy
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• 제19권2호
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• pp.85-98
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• 1989

The ventricular myocardia of 14, 16, 18 and 20-day-old rat fetuses and newborns have been studies by light and electron microscopic morphometrics. The volume density of the myocyte and interstitial compartments as well as volume, surface and numerical density of nuclei were estimated by light microscopic morphometrics. Whereas, the volume density of myofibrils and glycogen granules as well as the volume, surface and numerical density of mitochondria were assessed by electron microscopic morphometrics. The volume density of myocyte compartment of the ventricular myocardia in developing fetuses decreased, but increased in newborn rats. On the other hand, the volume density of the interstitial compartment increased in growing fetuses and decreased in newborns. In all groups the volume, surface and numerical density of nuclei decreased gradually with elongation of myocytes. Conversely, the volume, surface and numerical density of mitochondria and volume density of myofibrils and glycogen granules in ventricular myocytes incresed. The increase in numerical density of mitochondria probably reflects an increase in metabolic activity. Sarcomere length also increased during development.