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51.
Eucalyptus globulus is the one of the most economically important trees for pulp and paper industries due to its fast growth and short harvesting cycle. However, E. globulus is well known as a woody plant that is hard to propagate vegetatively. In this study, we found wide distribution of rooting ability among seven independent genotypes we tested. Analysis of the mechanism of adventitious rooting by using the auxin transport inhibitor, N-naphthylphthalamic acid, revealed that polar auxin transport is crucial in root formation. The gravitropism of the stem was highly correlated to the percentage of adventitious root formation. Hormonal analysis showed that the levels of indole-3-acetic acid (IAA) were the same between difficult-to-root and easy-to-root genotypes, whereas levels of IAAsp (indole-3-acetyl aspartic acid) were higher in the difficult-to-root genotype, indicating that IAA metabolism might play an important role in adventitious root formation in this species. Levels of several cytokinins exhibited differences between genotypes that varied in their cutting performance and rooting ability. Furthermore, higher level of cytokinin in elongating shoots were correlated with rooting percentage. Taken together, our results indicate that both auxins and cytokinins play a role in adventitious root formation in E. globulus, and that a complex interplay between the levels of auxins and cytokinins and their metabolism might result in root formation in this commercially important plant.  相似文献   
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A unique flower initiation of the wild Junebearing strawberry strain ‘CHI-24-1’ in Fragaria chiloensis occurs under 24 h DL and high temperature conditions. To introduce the floral initiation characteristics of ‘CHI-24-1’ into cultivated strawberries of F. × ananassa, a cross pollination was conducted between ‘CHI-24-1’ and the Japanese short-day type strawberry cultivar ‘Nyoho’. The floral initiation of ‘CHI-24-1’ was induced in both parent and daughter plants linked with runners under a 24 h DL and 23/20 C, but not 8 and 16 h DLs at the same temperatures. Of the 21 F1 hybrids grown under the 24 h DL, 12 showed flower truss production in the parent and/or daughter plants linked with runners. Among 64 F1 hybrids, 26 exposed to 8, 16 and 24 h DLs for 30 days produced no flower trusses. However, 32, one and five F1 hybrids produced flower trusses under the 24 h DL alone, 8 h DL alone and both the 8 and 24 h DLs, respectively. The results of the experiments indicated that none of the F1 hybrids were day-neutral plants, but approximately 60% had the characteristics of floral initiation under 24 h DL, which was inherited from the pollen parent of ‘CHI-24-1’. The importance of the unique floral initiation characteristics under 24 h DL with high temperature for strawberry breeding was discussed.  相似文献   
54.
Ovarian developmental stages and serum steroid hormone levels were examined at six different times of day (0100, 0600, 1000, 1300, 1600, 2000 h) in a marine teleost, the Japanese whiting Sillago japonica, which has an asynchronous-type ovary containing oocytes at various stages of development and spawns every day during a period ranging up to three months. The largest oocytes in the ovaries at the active vitellogenic or post-vitellogenic stages were found between 0100 and 1300 h. Oocyte maturation indicated by germinal vesicle breakdown (GVBD) occurred at 1600 h, and ovulated oocytes were observed in the ovaries collected at 2000 h. These processes were accompanied by a significant daily change in serum steroid hormone levels. The serum level of estradiol-17β showed a peak in fish with mature oocytes sampled at 1600 h. In these fish, the second-largest oocytes in the ovaries were at the initial stage of vigorous vitellogenesis, the secondary yolk stage. Therefore the highest level of serum estradiol-17β was considered to be due to the second-largest oocytes. Testosterone levels remained low and constant throughout the experimental period. The serum levels of 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-diOHprog) peaked at 1600 h at which time all fish had mature oocytes. These results indicate that the Japanese whiting possesses a diurnal rhythm of oocyte development including vitellogenesis, oocyte maturation and ovulation, and further suggest that daily cycles in oocyte growth and maturation which simultaneously take place in an ovary are regulated by diurnal secretions of estradiol-17β and the maturation-inducing steroid, 17α,20β-diOHprog.  相似文献   
55.
ABSTRACT:   In order to investigate the influence of estrogen and androgen on reproductive activities of male teleosts, male red sea bream were implanted with silicone capsules containing estradiol-17β (E2), testosterone (T) or 11-ketotestosterone (11-KT) in immature and early spermatogenic stages. One month after implantation of either E2 or T, the gonadosomatic index decreased in accordance with testicular regression in both stages. Implantation of E2 decreased circulating 11-KT levels but did not affect gonadotropin (GTH) subunits, follicle stimulating hormone-β (FSHβ), luteinizing hormone-β (LHβ), α glycoprotein subunit (αGSU) gene expression, and serum LH levels in both stages. Alternatively, T decreased serum 11-KT and LH levels, and FSHβ and LHβ mRNA levels in the early spermatogenic stage but not in the immature stage. These results suggest E2 may directly inhibit testicular development through the suppression of 11-KT production. Meanwhile, T may decrease serum 11-KT levels through the suppression of FSH and LH secretion, resulting to inhibition of testicular development in the early spermatogenic stage. Treatment with 11-KT did not affect the testis in either stage, whereas 11-KT increased LHβ and αGSU mRNA levels in immature, and decreased FSHβ mRNA levels in the early spermatogenic stage. These results suggest that 11-KT may have different effects on GTH subunit gene expression in each reproductive stage.  相似文献   
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A ten-year-old Shetland pony gelding showed low appetite, ataxia, peculiar swaying, clouding of consciousness, and ultimately died. At necropsy, multiple coalescing granulomatous foci were detected in the kidneys, and small necrotic lesions were found in the cerebellum. Histologic examination of the renal tissue sections revealed extensive granuloma, and Halicephalobus gingivalis-like nematodes were seen. Similar nematodes were found in the granulomatous or necrotic lesions of the renal lymph nodes and cerebellum, and were also frequently detected in cerebrospinal meningovascular lesions. Morphologic features together with partial ribosomal RNA gene sequences of the nematodes in the lesions revealed that they were H. gingivalis. The present results indicated that H. gingivalis caused granulomatous nephritis and meningoencephalomyelitis in this pony gelding.  相似文献   
58.
An 11-month-old Japanese Black steer with chronic bloat underwent clinical and histological analyses. During the observation period, it showed normal appetite and fecal volume but persistent chronic bloat symptoms. Compared to controls, the steer's feces contained undigested large straws. Necropsy revealed normal rumen, reticulum, and abomasum but a small omasum. The rumen, reticulum, and abomasum mucosa was normal, with well-developed ruminal papillae. However, severe hypoplasia of the omasal laminae was observed along with hypoplasia reticular groove and ruminoreticular fold. The contents of the reticulum, omasum, and abomasums comprised undigested large sized hay particles. The omasum papillae showed no pathological abnormalities. This is a rare case of a steer with chronic bloat probably caused by severe hypoplasia of the omasal laminae.  相似文献   
59.
Danazol, which has been used as a medicine for endometriosis, has a valid effect in pretreatment of patients receiving in vitro fertilization and embryo transfer, although its reproductive mechanism remains unclear. BALB/c mice were subcutaneously injected with danazol for 2 weeks. Blood and uteri were collected and cytokines were assayed. Following danazol treatment, an increase in pregnancy ratio was evident that was accompanied by up-regulation in serum macrophage-colony stimulating factor (M-CSF). RT-PCR analysis revealed that expression of M-CSF and Ly49, a phenotypic marker of natural killer (NK) cells, was up-regulated in the uteri of the danazol-treated mice. In immunohistochemical analysis, M-CSF and Ly49, together with alpha5 integrin, were clearly detected in the endometrium of the danazol-treated mice with very similar pattern of localization. These results suggest that danazol has an effect to promote pregnancy that induces recruitment of NK cells and a concomitant increase in the expression of M-CSF and alpha5 integrin in the uterus.  相似文献   
60.
Studies in vivo and in vitro suggest that curcumin is a neuroprotective agent. Experiments were conducted to determine whether dietary supplementation with curcumin has neuroprotective effects in a mouse model of Parkinson’s disease (PD). Treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) significantly induced the loss of dopaminergic cells in the substantia nigra and deletion of dopamine in the striatum, which was attenuated by long-term (7 weeks) dietary supplementation with curcumin at a concentration of 0.5% or 2.0% (w/w). Although curcumin did not prevent the MPTP-induced apoptosis of neuroblasts in the subventricular zone (SVZ), it promoted the regeneration of neuroblasts in the anterior part of the SVZ (SVZa) at 3 days after MPTP treatment. Furthermore, curcumin enhanced the MPTP-induced activation of microglia and astrocytes in the striatum and increased the expression of glial cell line-derived neurotrophic factor (GDNF) and transforming growth factor-β1 (TGFβ1) in the striatum and SVZ. GDNF and TGFβ1 are thought to play an important role in protecting neurons from injury in the central and peripheral nervous systems. These results suggest that long-term administration of curcumin blocks the neurotoxicity of MPTP in the nigrostriatal dopaminergic system of the mouse and that the neuroprotective effect might be correlated with the increased expression of GDNF and TGFβ1. Curcumin may be effective in preventing or slowing the progression of PD.  相似文献   
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