排序方式： 共有60条查询结果，搜索用时 312 毫秒
1.
Keitaro Yamanouchi Katsuyuki Nakamura Shiho Takeuchi Tohru Hosoyama Takashi Matsuwaki Masugi Nishihara 《Animal Science Journal》2021,92(1):e13573
The degree of intramuscular adipose tissue accumulation is one of the factors affecting meat quality. Accumulation of adipocytes is also observed under the pathological condition of skeletal muscle such as muscular dystrophy and sarcopenia. The origin of adipocytes seen in skeletal muscle is mesenchymal progenitor cells that can give rise to both adipocytes and fibroblasts. In the present study, we demonstrated that siRNA-mediated suppression of MyoD expression in rat skeletal muscle progenitor cell culture, which comprises both myogenic satellite cells and mesenchymal progenitor cells, resulted in diminished myotube formation and an unexpected spontaneous appearance of white adipocytes. Suppressing myomaker expression also resulted in complete absence of myotube formation without reducing MyoD expression, but no adipogenesis was seen in this scenario, indicating that decline in MyoD expression rather than decreased myotube formation is necessary to induce adipogenesis. In addition, spontaneous adipogenesis induced by suppressing MyoD expression in culture was inhibited by the conditioned medium from control culture, indicating that anti-adipogenic factor(s) are secreted from MyoD-positive myogenic cells. These results indicate the presence of regulatory mechanism on adipogenesis by myogenic cells. 相似文献
2.
Chiba S Suzuki M Yamanouchi K Nishihara M 《The Journal of reproduction and development》2007,53(2):297-307
Recent studies have demonstrated the presence of neurogenesis in the adult mammalian hippocampus, and it has been suggested that estrogen and various growth factors influence the processes of adult neurogenesis. The present study assessed cell proliferation in the dentate gyrus and the mRNA expression levels of granulin, insulin-like growth factor-I (IGF-I), and brain-derived neurotrophic factor (BDNF) in the hippocampus 4 h after treatment with estradiol benzoate (EB) in 3- and 12-month old ovariectomized rats. At 3 months of age, mRNA expression of granulin precursor and cell proliferation were increased by EB treatment, although the mRNA expressions of IGF-I and BDNF remained unchanged. At 12 months of age, however, neither mRNA expression of the three genes nor cell proliferation in the dentate gyrus were affected by EB treatment. In addition, 17beta-estradiol enhanced the proliferation of neural progenitor cells derived from hippocampal tissue of 3-month-old female rats in vitro; this was inhibited by neutralization of granulin with specific antibody. These results suggest that estrogen induces granulin gene expression in the hippocampus and that the product of this gene is involved in the mitogenic effects of estrogen in the dentate gyrus, although the responses to estrogen decline with age. 相似文献
3.
4.
5.
Mogi K Yonezawa T Chen DS Li JY Sawasaki T Nishihara M 《Domestic animal endocrinology》2003,25(2):175-182
Feeding behavior is regulated by neural signals in the hypothalamus, but secretory activities of these signals in vivo and their relationship with spontaneous feeding remain to be solved. In the present study, we investigated the correlation between neuropeptide Y (NPY) and somatostatin (SRIF) profiles in cerebrospinal fluid (CSF) and spontaneous feeding behavior in goats. CSF samples were collected every 15 min for 8 h from the third ventricle and feeding behavior was observed throughout the experimental period. The spontaneous feeding behavior, the mean duration of which was 58 min, occurred with an interval of 146 min. NPY in the CSF fluctuated in an episodic fashion with a 145 min interval. Each NPY episode was followed by spontaneous feeding with a time lag of 24 min. SRIF levels in CSF changed more frequently in a pulsatile manner and were related to neither NPY profiles nor feeding behavior. These results suggest that NPY, but not SRIF, is a physiological signal to drive feeding in goats. 相似文献
6.
This study aimed to characterize the relationship between the growth of rumen papillae in calves and the mRNA expression of insulin‐like growth factor‐binding proteins (IGFBPs) in the rumen papillae. The length of rumen papillae, the mRNA expression of IGFBPs in rumen papillae by quantitative real‐time PCR, and the presence of insulin‐like growth factors I and II (IGF‐I and II) by immunohistochemistry (IHC) were analyzed in nine Holstein calves divided into three groups: suckling (2 weeks, n = 3), milk‐continued (8 weeks, n = 3), and weaned (8 weeks, n = 3). The length of rumen papillae was greater (p < 0.01) in weaned calves than in suckling and milk‐continued calves, whereas the expressions of IGFBP2, IGFBP3, and IGFBP6 genes were lower (p < 0.05) in the rumen papillae of weaned calves than in milk‐continued calves. Thus, rumen papillae length and IGFBP2, 3, and 6 expressions were negatively correlated. The IHC analysis showed that IGF‐I and IGF‐II were present in the rumen epithelium of calves. These results suggested that the growth of rumen papillae after weaning is associated with the induction of IGFs by the low levels of IGFBP2, IGFBP3, and IGFBP6. 相似文献
7.
The effect of irradiance and temperature on the photosynthesis of two Japanese agarophytes, Gelidium elegans and Pterocladiella tenuis (Gelidiales), was determined using dissolved oxygen sensors and pulse amplitude modulated (PAM) fluorometry. Gross photosynthesis and dark respiration rates were determined over a range of temperatures (8–36 °C). The highest gross photosynthetic rates were 40.3 and 37.0 mg O2 g ww ?1 min?1 and occurred at 24.3 and 25.5 °C [95 % Bayesian credible interval (BCI) 20.7–28.0 and 23.4–28.3 °C], respectively. The dark respiration rate in G. elegans and P. tenuis increased with increasing temperature at a rate of 0.10 and 0.31 mg O2 g ww ?1 min?1 °C?1 , respectively. Modeling the net photosynthesis–irradiance (P–E) responses of G. elegans and P. tenuis at 20 °C revealed that the net photosynthetic rates quickly increased at irradiance levels below the estimated saturation irradiance of 88 and 83 µmol photons m?2 s?1, with a compensation irradiance of 14 and 19 µmol photons m?2 s?1, respectively. The highest value of the maximum effective quantum yield (Φ PSII) occurred at 20.1 °C (BCI 18.9–21.5 °C) and 21.3 °C (BCI 20.2–22.5 °C) for G. elegans and P. tenuis and was 0.49 and 0.45, respectively. These optimal temperatures of Φ PSII were relatively lower than those determined by the photosynthesis–temperature model of oxygen evolution. The temperature response of these species indicates that they are probably well adapted to the current range of seawater temperatures in the study site but that they are near the boundary of their tolerable limits. 相似文献
8.
H. Takahashi K. Fujita C. Yoshida M. Nishihara 《The Journal of Horticultural Science and Biotechnology》2016,91(2):148-155
Gentians are alpine plants and two endemic species, Gentiana triflora and G. scabra, are cultivated as ornamentals in Japan. Because most of the Japanese cultivars are F1 hybrids, seed germination rate is an important factor for maintaining these cultivars. However, germination rates frequently differ among cultivars. Poor germination is a severe problem for gentian production, although there is almost no difference in their germination period and growth rate. In this study, we compared seed germination rates among three cultivars of G. triflora. A high rate of seed germination was observed in ‘Majel’ (MJ) and ‘Iwate’ (IW), but a low rate was recorded in ‘Iwate-Yumeminori’ (YM). We conducted a targeted metabolome analysis using these cultivars to elucidate the potential cause of inhibited seed germination. Multivariate analysis revealed that the aberrant accumulation of specific amino acids and a decrease in energy metabolites were observed in YM seed. Furthermore, protein concentrations and proteolytic activities in YM seed were lower than in MJ seed. These results imply that energy depletion was the main reason for the decreased rate of germination and that this depletion inhibited processes involved in seed germination, including de novo synthesis of the proteins necessary for germination. 相似文献
9.
Role of serum myostatin during the lactation period 总被引：1，自引：0，他引：1
Myostatin, also known as GDF-8 (Growth/Differentiation Factor-8), is a member of the TGF-beta superfamily that negatively regulates skeletal muscle mass in mammals. Mutation of the myostatin gene in mice, cattle, and humans causes a massively developed skeletal muscle, characterized by muscle hypertrophy and hyperplasia. Although myostatin is predominantly expressed in skeletal muscle tissue, several recent studies have shown the presence of myostatin protein in blood and suggested a possible role for circulating myostatin in the regulation of skeletal muscle mass. In the present study, we examined changes in the levels of active form myostatin (13 kDa) in serum after birth by Western blot analysis to predict the role of serum myostatin in early postnatal muscle growth in the rat. Interestingly, the amount of active form myostatin in serum increased after birth and then decreased along with ageing after weaning. To clarify the role of increased serum myostatin during the postnatal period, we administrated follistatin, an inhibitor of myostatin activity, into postnatal rats intraperitoneally just after birth. Follistatin-administration during the postnatal period caused selective hypertrophy of type II muscle fibers in the soleus muscle. These results demonstrate that myostatin in serum acts on skeletal muscle and negatively regulates early postnatal muscle growth. 相似文献
10.
Jayasekara WS Yonezawa T Ishida M Yamanouchi K Nishihara M 《The Journal of reproduction and development》2005,51(2):265-272
20Alpha-hydroxysteroid dehydrogenase (20alpha-HSD) catalyzes the conversion of progesterone to its inactive form 20alpha-dihydroprogesterone (20alpha-OHP). 20Alpha-HSD is expressed in the murine placenta, suggesting a role, yet unidentified, played by this enzyme during the course of pregnancy. To elucidate the possible roles of 20alpha-HSD during pregnancy, 20alpha-HSD gene expression in the placenta was examined by Northern blot analysis, and progestin (progesterone and 20alpha-OHP) concentrations in the maternal and fetal sera and the amniotic fluid were measured by radioimmunoassay in pregnant Shiba goats. The expression of 20alpha-HSD mRNA was observed in the placenta and the intercaruncular part of the uterus during mid to late pregnancy. Analysis by in situ hybridization revealed that 20alpha-HSD mRNA was mainly localized in the endometrial epithelium of the caruncle side of the placenta. Considerable enzyme activity of 20alpha-HSD was also detected in the cytosolic fraction of the placenta and intercaruncular part of the uterus. Although concentrations of progesterone and 20alpha-OHP in the maternal serum showed similar profiles, progesterone levels in the fetal serum stayed extremely low throughout the pregnancy. The 20alpha-OHP concentration in the fetal serum was always higher than that in the maternal serum. In the amniotic fluid, the concentrations of both progesterone and 20alpha-OHP remained at very low levels throughout the pregnancy. These results support the notion that 20alpha-HSD protects the fetus from the cytotoxic effects of progesterone, and thereby maintains the normal development of the fetus. 相似文献