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Bérard J Kalbe C Lösel D Tuchscherer A Rehfeldt C 《Histochemistry and cell biology》2011,136(2):217-225
In pigs, myogenesis is a biphasic phenomenon with the formation of primary and secondary fibres. Hyperplasia was reported
to be accomplished around 90 days of gestation. However, some studies suggest a substantial increase in the total fibre number
(TFN) from birth to weaning by counting fibre number in the muscle cross sections. The aim of this study was to establish
in which way TFN increases after birth and whether this increase is imputable to new (tertiary) myofibres and/or fibre elongation.
The semitendinosus muscle of 128 piglets was examined at days 1 (n = 63), 7 (n = 12), 21 (n = 12), and 28 (n = 41) of age. TFN was increased at days 7, 21 and 28 of age when compared with day 1 (P < 0.01). From day 1 to 28, TFN increased from 463 × 103 to 825 × 103. Microscopy of longitudinal and transversal serial sections revealed that at day 7 of age very small fibres expressing the
embryonic myosin heavy chain (MyHC) isoform were apparent all over the muscle. In addition, intrafascicular terminations of
normal-sized fibres expressed the embryonic MyHC isoform. These data suggest that the TFN in the pig muscle is not fixed at
birth and its postnatal increase may be related to both elongation of existing muscle fibres and genesis of tertiary myofibres,
mainly between birth and 3 weeks of age. 相似文献
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Studies focusing on the development of morphological novelties suggest that patterning genes underlying traditional appendage
development (i.e. mouthparts, legs, and wings) also play important roles in patterning novel morphological structures. In
this study, we examine whether the expression and function of a member of the TGF-β signaling pathway, decapentaplegic (dpp), promotes development of a morphologically novel structure: beetle horns. Beetle horns are complex secondary sexual structures
that develop in the head and/or prothorax, lack obvious homology to other insect outgrowths, and vary remarkably between species
and sexes. We studied dpp expression through in situ hybridization, performed functional analyses with RNA interference, and gathered allometric measurements
to determine the role of dpp during both pronotal and head horn development in both sexes of two morphologically dissimilar species in the Onthophagus genus, Onthophagus binodis and Onthophagus sagittarius. Our findings show that in addition to affecting growth and patterning of traditional appendages, dpp regulates beetle horn growth and remodeling. 相似文献
105.
Stefan K?rst Riyan Cheng Armin O. Schmitt Hyuna Yang Fernando Pardo Manuel de Villena Abraham A. Palmer Gudrun A. Brockmann 《Mammalian genome》2011,22(9-10):530-543
Intramuscular fat content and water-holding capacity are important traits in livestock as they influence meat quality, nutritive value of the muscle, and animal health. As a model for livestock, two inbred lines of the Berlin Muscle Mouse population, which had been long-term selected for high muscle mass, were used to identify genomic regions affecting intramuscular fat content and water-holding capacity. The intramuscular fat content of the Musculus longissimus was on average 1.4 times higher in BMMI806 than in BMMI816 mice. This was accompanied by a 1.5 times lower water-holding capacity of the Musculus quadriceps in BMMI816 mice. Linkage analyses with 332 G3 animals of reciprocal crosses between these two lines revealed quantitative trait loci for intramuscular fat content on chromosome 7 and for water-holding capacity on chromosome 2. In part, the identified loci coincide with syntenic regions in pigs in which genetic effects for the same traits were found. Therefore, these muscle-weight-selected mouse lines and the produced intercross populations are valuable genetic resources to identify genes that could also contribute to meat quality in other species. 相似文献
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Pop N Igel P Brennauer A Cabrele C Bernhardt GN Seifert R Buschauer A 《Journal of receptor and signal transduction research》2011,31(4):271-285
The four functionally expressed human neuropeptide Y receptor subtypes (hY(1)R, hY(2)R, hY(4)R, hY(5)R) belong to class A of the G-protein-coupled receptors (GPCRs) and interact with pertussis toxin-sensitive G(i/o)-proteins. The number of small molecules described as ligands for hY(1)R and hY(5)R exceeds by far those for hY(2)R. Potent non-peptidergic ligands for the hY(4)R are not available so far. Here, we report on the functional reconstitution of the hY(2)R and the hY(4)R in Sf9 insect cells using the baculovirus system. Sf9 cells were genetically engineered by infection with up to four different baculoviruses, combining the receptors with G-proteins of the G(i/o) family and regulators of G-protein signaling (RGS) proteins to improve signal-to-noise ratio. In steady-state GTPase assays, using pNPY (Y(2)) and hPP (Y(4)), the GPCRs coupled to various G(i)/G(o)-proteins and both, RGS4 and GAIP, enhanced the signals. Co-expression systems hY(2)R + G?(i2) and hY(4)R + G?(i2)/G?(o) + RGS4, combined with G?(1)?(2), yielded best signal-to-noise ratios. hY(2)R function was validated using both agonistic peptides (NPY, PYY, NPY(13?36)) and selective non-peptidergic antagonists (BIIE0246 and derivatives), whereas the hY(4)R model was characterized with peptidergic agonists (PP, NPY, GW1229, and BW1911U90). Tunicamycin inhibited receptor N-glycosylation diminished NPY signals at hY(2)R and abolished hY(4)R function. Investigations with monovalent salts showed sensitivity of hY(4)R toward Na(+), revealing moderate constitutive activity. After validation, an acylguanidine (UR-PI284) was identified as a weak non-peptide Y(4)R antagonist. In summary, the established steady-state GTPase assays provide sensitive test systems for the characterization of Y(2) and Y(4) receptor ligands. 相似文献
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