Development & reproduction最新文献

While Pacific oysters are important commercial aquaculture species worldwide, the effect of hormonal regulation and environmental conditions on growth and taste profile have not been fully known. Insulin-like growth factor (IGF) systems are known to play a major role in regulating neuroendocrine functions across various physiological processes and are particularly involved in growth. IGFs expression also is directly related to the nutritional status of vertebrates, however, full mechanism has not been clearly identified in bivalves. In this study, differences in growth, IGFs expression, and taste according to cultivation site of Pacific oysters were investigated. Oysters were collected in three different spawning sites located on the south coast of Korea in July 2022 and hardened until June 2023. Then, the oysters were cultured in two different growing sites (Tongyeong site, TS; Geoje site, GS) for six months. The total weight of oysters, along with their condition index and tissue weight rate, was significantly higher in TS. Additionally, IGF expression was higher in TS during most of the sampled months. However, oysters from the GS scored higher in taste evaluations. The IGFs system in oysters shows a similar trend to previous studies, with higher levels in faster-growing individuals, suggesting oysters in TS were more adequately nourished by the surrounding environment in this research. However, in taste evaluation, oysters from the GS showed better results than those from the TS. Despite these results, determining whether one site is superior in certain aspects is still not fully possible, which warrants further investigations.

We previously reported that metformin, a widely prescribed antidiabetic drug, induces the accumulation of triglyceride (TG) together with the apoptotic death of H4IIE via AMP-activated protein kinase (AMPK) in hepatocellular carcinoma (HCC) cells. However, the effect of cytoplasmic fat accumulation on the growth of HCCs remains controversial. Herein, we investigated the effect of fatty acid synthase (FASN) inhibitors on the basal- or metformin-induced changes including the content of cytoplasmic TG and the viability of HCC cells. Cerulenin and C75, inhibitors of FASN, did not significantly affect the basal TG content but dose-dependently suppressed the metformin-induced increase in the cytoplasmic TG content. Metformin-induced apoptosis of H4IIE cells was also significantly reduced by cerulenin and C75. Metformin enhanced the generation of reactive oxygen species which was suppressed by adding cerulenin or T75. Cerulenin also stimulated cell migration, which was suppressed by metformin. However, the degree of suppressive effect of metformin on TG synthesis, apoptosis, and cell migration was much more prominent by the inhibition of AMPK by compound C than cerulenin. In conclusion, our study found that excess fat accumulation is responsible for the apoptosis of H4IIE HCC cells and is informative for designing anti-tumor reagents, especially in HCC.

Lutropin/choriogonadotropin receptor (LH/CGR) is a member of the G protein-coupled receptor superfamily. LH/CGRs in fish and mammalian species have been reported to contain naturally occurring, constitutively activating, and inactivating mutations in highly conserved regions. The present study was designed to determine the functional aspect of eel LH/CGR signal transduction. Biochemical analysis was performed using cells transfected with wild-type eel LH/CG (eel LH/CGR-wt) or with activating (designated eel LH/CGR-M410T, L469R, and D590Y) and inactivating (eel LH/CGR-D 417N and Y558F) mutants. We also generated a mutant (eel LH/CGR-t651) in which the C-terminal cytoplasmic tail was truncated at residue 651. Activating mutant cells expressing eel LH/CGR-M410T, L469R, and D590Y exhibited 1.4-, 8.7-, and 4.0-fold increases in the basal cAMP response, respectively, without recombinant equine chorionic gonadotropin (rec-eCG) agonist treatment. In inactivating mutants (eel LH/CGR-D417N and Y558F), the cyclic adenosine monophosphate (cAMP) response did not result in completely impaired signal transduction. However, the eel LH/CGR-t651 mutant did not exhibit any cAMP signaling following high-agonist treatment. Rmax values did not increase with further rec-eCG agonist stimulation. Our results suggest that constitutively activating and inactivating eel LH/CGR mutants with highly conserved amino acids exhibit a significant signal transduction pathway for glycoprotein hormone receptors. Eel LH/CGRs in activating and inactivating mutants are usually processed by receptor-mediated signaling following rec-eCG agonist stimulation.

Maintenance of neural progenitors requires Notch signaling in vertebrate development. Previous study has shown that Jagged2-mediated Notch signaling maintains proliferating neural progenitors in the ventral spinal cord. However, components for Jagged-mediated signaling remain poorly defined during late neurogenesis. Here we performed yeast-two hybrid screening by using the intracellular domain (ICD) of zebrafish Jagged2, and investigated a possible role of PEX1 as a component of Notch signaling for the cell-fate decision and the differentiation of neural precursors in p3 domain. Western blotting showed that zebrafish PEX1 might interacts with the ICD of zebrafish Jagged2 physically. PEX1 morpholino-injected embryos showed the increased number of GABAergic KA" neurons as well as the ectopic expression of secondary motor neurons in the p3 domain. The increased number of KA" neurons was also observed in the zebrafish embryos with PEX1 mutation induced by CRISPR/Cas9. These phenotypes resemble with that of Jagged2 morphant. Our observations imply that a critical role of PEX1 in the cell-fate decision of proliferating neural precursors in the p3 domain during the continuing growth and development of the vertebrate nervous system.

The epididymal fat is required for the maintenance of normal spermatogenesis, and the lipectomy of epididymal fat at different postnatal age results in disrupted expression patterns of several testicular steroidogenic enzymes. The current research examined the effect of epididymal fat lipectomy at different postnatal ages on expression of cytochrome 5α-reductase I, cytochrome P450 aromatase, androgen receptor (AR), and estrogen receptors (ER) α and β in the mouse testis after 2 weeks of the lipectomy. The lipectomy of epididymal fat at 2 months of postnatal age resulted in significant increases of expression levels of cytochrome 5α-reductase I, cytochrome P450 aromatase, AR, and ER α and β. However, expressions of these genes in the testis were significantly decreased by the lipectomy of epididymal fat at 5 months of postnatal age. The lipectomy of epididymal fat at 8 months and 12 months of postnatal ages did not influence expression levels of cytochrome 5α-reductase I, cytochrome P450 aromatase, AR, and ER β. However, a significant decrease of ER α was detected with the lipectomy of epididymal fat at 12 months of postnatal age. These observations suggest that expression of these genes in the testis by the influence of the epididymal fat is more susceptible at the earlier postnatal development than at the later postnatal period.

The ascidian larvae, which display a chordate ground body plan, are left-right asymmetric in several structures, including the brain vesicle. In ascidian larvae, the ocellus and otolith pigment cells, which are thought to detect light and gravity respectively, are located on the right side of the brain vesicle, while the coronet cells, which are presumed to be dopaminergic, are located on the left side. To study how left-right asymmetry of the brain vesicle in the ascidian Halocynthia roretzi larva is determined, I attempted to isolate a gene that is expressed in the brain vesicle. As a result, an ascidian Parkin co-regulated gene (PACRG) orthologue was cloned. Expression of PACRG begins weakly in the head region of the late tailbud embryos, and it thereafter is observed on the left side of the brain vesicle of the larvae just before hatching. The location of PACRG expression is estimated to overlap with the area stained by the coronet cell-specific antibody. Thus, it is suggested that PACRG might be involved in the formation of the left-side structures of the brain vesicle, including coronet cells, during ascidian embryogenesis.

This study investigated the progressive morphological alterations and digestive tract development in larval and juvenile red spotted grouper, Epinephelus akaara across growth stages. External shape observations were made using an optical microscope, and the development of the digestive tract was investigated using histological methods. At 1 day after hatching (DAH), the digestive tract appeared as a straight tube extending between the ventral side and yolk-sac. At 3 DAH, the yolk was nearly absorbed, liver and pancreatic tissue began to develop. At 5 DAH, the opening of the mouth and anus allowed for the ingestion of external food, and the expansion of the intestinal lumen was observed. Gastric lumen differentiation became evident between the anterior intestine and esophagus. At 10 DAH, mucosal folds had formed in the rectum, and goblet cells were observed in the esophagus. At 20 DAH, mucosal folds in the stomach developed, and an increase in goblet cells was observed throughout the digestive organs. At 30 DAH, pyloric caeca and further gastric development were observed. By 40-50 DAH, sphincters between the esophagus, stomach, and intestine were clearly defined, resembling the adult digestive system. These findings suggest transitioning larvae to commercial pellets around 30 DAH, coinciding with the development of gastric glands and pyloric caeca. This research provides critical insights for optimizing feeding schedules to improve growth and survival rates during red spotted grouper seed production.

Autotaxin (ATX), also known as ectonucleotide pyrophosphatase/phosphodiesterase family member 2 (ENPP 2), is an enzyme with lysophospholipase D activity that converts lysophosphatidylcholine into lysophosphatidic acid (LPA). One of the LPA receptors, LPA3, is positively and negatively regulated by progesterone and estrogen, respectively. Furthermore, ATX expression in the rat uterus could be under the control of estrous cycle. In the present study, we used young normal cycling rats for further assess the uterine ATX expression and localization by reverse transcription PCR (RT-PCR) and immunohistochemistry, respectively. In the RT-PCR study, ATX mRNA level at Metestrus (1.00±0.026 AU) was significantly higher than that at Proestrus (0.42±0.046 AU, p<0.001) and the level at Diestrus (0.75±0.107 AU, p<0.05) was significantly higher than that at Proestrus. Among the luminal epithelial cells, the order of the ATX signal intensities was Metestrus>Diestrus>Proestrus>Estrus. Among the myometrial cells, the order of the signal intensities was Diestrus>Proestrus>Estrus>Metestrus. Among the glandular epithelial cells, the order of the signal intensities was Proestrus>Estrus=Metestrus= Estrus. The present study indicates that expression and localization of uterine ATX may be under the control of sex steroids during the estrous cycle. Further studies on the ATX signaling-sex steroid relationship will be providing better understanding on in normal and pathophysiological state of uterus.

This study investigated the fin development and morphological characteristics according to larval growth in order to obtain information on behavioral characteristics and optimal stocking density during red seed grouper seed production. To examine the growth and fin development process of the larvae, we randomly sampled at 1, 3, 5, 7, 9, 10, 11, 13, 15, 17, 19, 20, 25, 30, 39, 45, 51, and 72 days after hatching. External morphology was observed and measured using an optical microscope. To observe skeletal development, larvae at 13, 20, 30, and 72 days after hatching were fixed in formalin and stained for cartilage and bone examination. At 9-10 DAH, red spotted grouper larvae (2.74±0.1 to 3.0±0.2 mm TL) exhibited a second dorsal fin spine and pelvic fin spine, which subsequently elongated. At 19-20 DAH, the larvae (5.7±0.1 to 6.1±0.1 mm TL) have the lengths of the second dorsal fin spine and pelvic fin spine average 34% and 31% to total length, respectively. From 30 to 72 DAH (12.6±0.4 to 56.0±0.2 mm TL), the length of the second dorsal fin spine and pelvic fin spine to total length decreased from 27% to 8% for the dorsal fin and 21% to 14% for the pelvic fin, respectively. At 30 DAH (12.6±0.4 mm TL), the larvae reached the complete count of fin rays in each fin. At 39 DAH (20.28±3.07 mm TL), the larvae had fin shapes similar to those of adults. At 13-30 DAH (4.2±0.1 to 12.6±0.9 mm TL), barbs and spinules were distributed along the ridges of the second dorsal and pelvic fin spines. However, at 72 DAH, these barbs and spinules were no longer observed on the fins. During the seed production process, red spotted grouper larvae tend to cluster in the morning, and during this time, entanglement of barbs and spinules on the second dorsal and pelvic fin spines can lead to mortality. Therefore, it is considered essential to focus on managing the behavioral patterns and appropriate rearing density of red spotted grouper larvae from the emergence of barbs and spinules on the second dorsal and pelvic fin spines until they regress and metamorphosis is completed.

Artificial sexual maturation of eel (Anguilla japonica) involves rearing in seawater and injecting salmon pituitary extract (SPE). The salinity of seawater and components of SPE influence hormonal activities of the eel pituitary, leading to gonad development. This study investigated the direct effects of salinity change and SPE treatment on the eel pituitary gland using primary cell cultures. Pituitary cells were cultured into four experimental groups: control culture (control), SPE-treated culture (SPE), NaCl-treated culture (NaCl) and NaCl+SPE treated culture (NaCl+SPE). We investigated the expression of genes presumably related to reproduction and/or salinity, including luteinizing hormone (LHβ), follicle stimulating hormone (FSHβ), progesterone receptor-like (pgrl), prolactin (PRL), dopamine receptor D4 (drd4), neuropeptide B/W receptor 2 (NPBWR2) and relaxin family peptide receptor 3-2b (rxfp3-2b). Gene expression analysis revealed significant upregulation of LHβ in SPE and NaCl+SPE groups compared to control and NaCl (p<0.05). FSHβ expression did not show any significant changes. PRL showed a significant decrease in the NaCl group (p<0.05). Pgrl, NPBWR2, drd4, and rxfp3-2b displayed the highest expression in the control group, with downregulation observed in all treatment groups (NaCl, SPE, and NaCl+SPE) (p<0.05). This study demonstrated the direct effects of salinity changes and SPE treatment on the eel pituitary. Results from this study also suggest that salinity change is necessary but work together with SPE to induce reproductive process, and that LHβ, pgrl, PRL, drd4, NPBWR2, and rxfp3-2b genes are obviously associated with reproduction and salinity changes in eels.