Potent Influence of Exogenous Melatonin on Oocyte Maturation in the Longchin Goby, .

Effects of changes in photoperiod on the reproductive events in fish are suggested to be mediated mainly via the action of melatonin (MEL). Changing levels of plasma MEL throughout the day and year are suggested to influence the hypothalamus-pituitary-gonadal axis in fish. Therefore, in this study, we aimed to investigate the effects of MEL on oocyte maturation and germinal vesicle breakdown (GVBD) in the marine fish, , .

Sex Steroid Metabolism in Red Spotted Grouper, during Oocyte Maturation.

We studied steroid metabolites produced from red-spotted grouper ovarian follicles during maturation. Oocytes with 350-500 μm diameter were incubated in the presence of [H] 17α-hydroxyprogesterone as a precursor. Steroid metabolites were extracted from incubated media and oocytes.

Mature and Bi-Sexual Phase Gonad Occurrence in Cultured Red Spotted Grouper, .

This study reports the presence of mature and bi-sexual phase gonads in red spotted grouper, after less than a year of cultivation in a commercial indoor tank and a net cage. In December 2018, juveniles were placed in an indoor tank and cultured for five months. In June 2019, the fish were transferred to a net cage and cultured until September.

Thermal stress induces a distinct transcriptome profile in the Pacific oyster Crassostrea gigas.

Oysters are frequently subjected to heat stress during tidal emersion/immersion cycles in their habitats due to attachment on the rocky shore. To understand the effect of temperature elevation on the whole transcriptome over time, the Pacific oyster Crassostrea gigas was exposed to seawater temperature 32°C for 72h from the control 20°C. RNA-seq identified differentially expressed stress responsive transcripts upon thermal stress in the gill tissues of C.

Expression of Vimentin Intermediate Filament for Vascular Development in Olive Flounder (Paralichthys olivaceus).

Cardiovascular system is the primary organ to develop and reach a functional state, which underscores the essential role of the vasculature in the developing embryo. The vasculature is a highly specialized organ that functions in a number of key physiological works including the carrying of oxygen and nutrients to tissues. It is closely involved in the formation of heart, and hence it is essential for survival during the hatching period.

RAG-1 and IgM Genes, Markers for Early Development of the Immune System in Olive Flounder, Paralichthys olivaceus.

Fish larvae are immediately exposed to microbes from hatching to maturation of their lymphoid organs, therefore effective innate mechanisms is very important for survival. However, the knowledge of the development of immune system in fish is limited and in demand now. In vertebrates, recombination-activating gene 1 (RAG-1) and immunoglobulin M (IgM) have been considered as very useful markers of the physiological maturity of the immune system.

Histological Analysis of Early Gonadal Development and Sex Differentiation in Chameleon Goby, Tridentiger trigonocephalus.

This study describes the developmental process of gonads in chameleon goby, Tridentiger trigonocephalus from the stage of hatching to 100 days after hatching (DAH). Based on histological observation, the primordial germ cells were observed in mesentery between mesonephric duct and gut at 15 DAH (total length, TL: 6.8±0.

Reproductive Cycle of Chameleon Goby, Tridentiger trigonocephalus in the Southern Coastal Waters of Korea.

The objective of this study was to characterize the reproductive cycle of the chameleon goby, T. trigonocephalus. Gonadal development was investigated using a histological method.

Stage and Tissue Specific Expression of Four TCR Subunits in Olive Flounder (Paralichthys olivaceus).

TCR subunits are members of membrane-bound receptors which allow the fast and efficient elimination of the specific fish pathogens have regulated function in adaptive immunity. Sequence structure of TCR subunits have been reported for various teleosts, but the information of each TCR subunit functional characterization through expression analysis in fish was unknown. In this study, we examined the gene expression of TCR subunits in the early developmental stages and observed transcript levels in various tissues from healthy adult olive flounder by RT-PCR.

Expression of Perforin Gene for Early Development of Nephrons in Olive Flounder (Paralichthys olivaceus).

The innate immune system is the only defense weapon that invertebrates have, and it is the fundamental defense mechanism for fish. The innate immune response is important in newly hatched flounders because it is closely involved in the initial feeding phase, which is why it is essential for survival during the juvenile period. The expression analysis of genes involved in the innate immune response in the olive flounder (Paralichthys olivaceus) in the days after hatching is incomplete.

The Expression Analysis of Complement Component C3 during Early Developmental Stages in Olive Flounder (Paralichthys olivaceus).

Fish larvae are immediately exposed to microbes from hatching to maturation of their lymphoid organs, therefore effective innate mechanisms is very important for survival in such an environment. The key component of innate immune system, C3 is central protein of all activation pathways of the complement system, leading to inflammatory reactions, such as opsonisation, chemotaxis, and cell lysis of pathogens. Although, innate mechanisms is essential for survival in the early stage of development, little is known about defence mechanisms.

Expression Analysis of Visual Arrestin gene during Ocular Development of Olive Flounder (Paralichthys olivaceus).

Olive flounder (Paralichthys olivaceus) is one of the commercial important flatfish species in Korea. The ocular signal transduction pathway is important in newly hatched flounders because it is closely involved in the initial feeding phase thus essential for survival during the juvenile period. However, the study of gene expression during ocular development is incomplete in olive flounder.

Expression Analysis of Cathepsin F during Embryogenesis and Early Developmental Stage in Olive Flounder (Paralichthys olivaceus).

Cathepsins are members of the multigene family of lysosomal cysteine proteinases and have regulated function in several life processes. The potential role of cathepsin F cysteine gene was expected as protease in the yolk processing mechanism during early developmental stage, but expression analysis was unknown after fertilization. The alignment analysis showed that amino acid sequence of cathepsin F from olive flounder liver expressed sequence tag (EST) homologous to cathepsin F of other known cathepsin F sequences with 87-98% identity.

The Morphological Study of Wild and Farmed Olive Flounder (Paralichthys olivaceus): The Role of Indirect Selection within and between Populations.

This study was conducted to analyze the difference of body types within and between wild and farmed populations of olive flounder Paralichthys olivaceus using measured records of morphological traits. The results showed that surveyed traits and standard deviation were 1,355±742 g of body weight, 48.01±7.

Differential Expression Patterns of Crystallin Genes during Ocular Development of Olive Flounder (Paralichthys olivaceus).

Olive flounder Paralichthys olivaceus is one of the most widely cultured fish species in Korea. Although olive flounder receive attention from aquaculture and fisheries and extensive research has been conducted eye morphological change in metamorphosis, but little information was known to molecular mechanism and gene expression of eye development- related genes during the early part of eye formation period. For the reason of eyesight is the most important sense in flounder larvae to search prey, the screening and identification of expressed genes in the eye will provide useful insight into the molecular regulation mechanism of eye development in olive flounder.

Changes in Plasma Sex Steroid and Cortisol Levels during Annual Reproductive Cycle of Ribbed Gunnel, Dictyosoma burgeri.

We investigated the changes in plasma sex steroid hormones, testosterone (T), estradiol-17β (E2), 17,20β -dihydroxy-4-pregnen-3-one (17α20βP), 11-ketotestosterone (11KT) and cortisol levels from ribbed gunnel, Dictyosoma burgeri in associated with annual reproductive cycle. The gonadosomatic index (GSI) of females increased from November, peaked in February and decreased rapidly from March. The GSI of males also increased from November, peaked in January and then decreased gradually.

Effects of BPA and DES on longchin goby (Chasmichthys dolichognathus) in vitro during the oocyte maturation.

This study was performed in order to assess whether bisphenol (BPA) and diethylstilbestrol (DES) had agonistic or antagonistic effects on oocyte maturation using marine fish. We tested the effects of these chemicals on in vitro maturation, germinal vesicle breakdown (GVBD), assay using oocytes from the longchin goby, Chasmichthys dolichognathus. During the maturation process, low concentrations of BPA and DES triggered GVBD depending on the stage of oocyte development; BPA at 0.