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EN
Intensive selection conducted within closed populations has led to the creation of specialized chicken strains that differ significantly in meat yield and reproduction performance. The effect of the selection conducted on the birds is differentiation identified not only on the molecular but also on the cellular level, among other things in the skeletal muscles. The aim of this study was to compare the structure of chosen homological skeletal muscles from Leghorn chickens (LSL), originating from parent flock, intensively selected for reproductive traits and from conservative flock (G99), unselected for many generations. The structure of musculus pectoralis superficialis and musculus biceps femoris (the thickness of the muscle fibres and the share of the fibre types in the bundle) in 8 and 20 week old chickens was compared. A significant impact of the origin on all examined slaughter parameters was recorded. Body weight before slaughter, carcass weight and the weight of breast and leg muscles in 8 weeks old LSL chicken made up from 60%to about 85%of the respective values in the G99 Leghorn. Lack of red fibres in the breast muscles of all the individuals from the parental flock (LSL) was noted, whereas in 12 individuals (among 24) from the conservative flock (G99), red fibres were observed in this muscle from 2.75%up to 7.09 %. White fibres in 8 week old chicks were always thicker, both in pectoralis superficialis and biceps femoris muscle in birds with higher body weight as well as higher weight of breast and legs muscles, i.e. in chicks from conservative flock (G99), P<0.01. However, in 20 week old birds, the diameters of the white fibres were similar in both groups. Also the diameters of the red fibres in musculus biceps femoris in 8 week old chickens were higher in cockerels and pullets from conservative flock (G99).
EN
The effect of tenotomy on Extensor Digitorum Longus (EDL) muscle, brought about by removal of anterior tibialis muscle was studied in the rat. Hypertrophy as well as hyperplasia of the muscle fibres were observed following tenotomy of intact muscle. The transplanted muscle regenerated after tenotomy in the form of a flat strap. The weight, length, breadth and total muscle area of intact muscle increased but decreased in transplanted muscle following tenotomy. The number of muscle fibres/microscopic field increased during the entire experiment in intact muscle after tenotomy, while in transplant the number of fibres first decreased and then increased. The diameter of intact and transplanted muscle increased after tenotomy. The number and diameter of nuclei was normalized at the end of experiment in both groups. The DNA and RNA content was increased in intact muscle after tenotomy. In transplant DNA and RNA content first increased but than decreased. The protein content was increased in intact muscle at the end of the experiment but decreased in transplant after tenotomy.
EN
An exceptional muscle development in some meat-producing animals is due to the increase in the number of muscle fibers (hyperplasia) or increase in their individual diameter (hypertrophy). The genetic mechanism of the former is well known. It results from mutation in the myostatin gene. The determination of muscular hypertrophy is poorly understood. In pigs this phenomenon is associated with muscular hypermetabolism and contraction induced by stress. Muscle development is controlled by genes called muscular regulatory factors. Four genes belong to this family: myogenin, myf-3, myf-5 and MRF4. While myf-3 and myf-5 are responsible for establishment and maintenance of skeletal myoblasts, myogenin and MRF4 control differentiation of myoblasts into myotubes. Their activity is influenced by other genes and physiological factors. Understanding of the mechanisms involved in myogenesis would provide a useful tool for controlling meat production in farm animals.
EN
Differences in gene expression in muscles from Chinese black-boned sheep and local common sheep were investigated using mRNA differential display. One differentially expressed novel gene was identified through semi-quantitative RT-PCR, and the full-length cDNA sequence was then obtained using the rapid amplification of cDNA ends (RACE). The nucleotide sequence of this gene is not homologous to any of the known sheep genes, but it contains an open reading frame encoding a protein of 416 amino acids, which has high homology with matrix metallopeptidase 7 (matrilysin, uterine) (MMP7) of 10 species: bovine (93%), rhesus monkey (75%), human (74%), pig (73%), chimpanzee (73%), dog (73%), horse (72%), mouse (66%), rat (65%), and chicken (53%). Thus the novel gene can be defined as the sheep MMP7 gene. It was finally assigned to GeneID:100192317. The phylogenetic tree analysis revealed that the sheep MMP7 gene is closely related to the bovine MMP7. Our experiment is the first one to establish the primary foundation for further research on the sheep MMP7 gene.
Folia Biologica
|
2003
|
vol. 51
|
issue 1-2
125-128
EN
Carassius auratus gibelio was chosen as an organism with a high level of tolerance against heavy metal to investigate changes in monovalent ions content in its tissues. Fish were kept in 10 ppm Cu2+ (3h), CrO4 2- (96h), Co2+(96h), Pb2+ (8h) and control (96h) solutions, then tissues were dissected and prepared for X-ray microanalysis. K+, Na+ and Cl- concentration was measured and calculated. Short periods of time of fish acclimation to Cu2+ (3h) and Pb2+ (8h) caused fish to suffocate as a consequence of heavy metal ions binding to gill mucopolisaccharides. Cl- and Na+ content decreased after Cu2+ treatment in kidney cells and muscle fibers, and so did K+ concentration in gill cells in comparison to control. After that CrO4 2- ions acclimation changes in all tissues and in all measured ions were observed. Similar effects were observed in Co2+ ions treatment but not for muscle fibers. Pb2+ ions caused an elevation of Cl- and Na+ ions content in gill cells and muscle fibers but decreasing in liver and kidney cells in comparison to control. Changes in monovalent ions concentration are probably related to heavy metal ions influence on ionic pump activity, their interaction with metabolic enzymes, ATP production or membrane phospholipids.
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