DSpace 集合:
http://scholars.ntou.edu.tw/handle/123456789/198
2024-03-28T20:08:25ZSuccessive responses of three coral holobiont components (coral hosts, symbiotic algae, and bacteria) to daily temperature fluctuations
http://scholars.ntou.edu.tw/handle/123456789/24714
標題: Successive responses of three coral holobiont components (coral hosts, symbiotic algae, and bacteria) to daily temperature fluctuations
作者: Hsieh, Yunli Eric; Lu, Chih-Ying; Liu, Po-Yu; Kao, Jia-Min; Yang, Sung-Yin; Wu, Chien-Yi; Wong, Jing-Wen Michelle; Shikina, Shinya; Fan, Tung-Yung; Yang, Shan-Hua
摘要: Corals and their associated microbiota form a "holobiont," which includes symbiotic algae and other associated microbiota dominated by bacteria. The composition of holobiont is influenced by various environmental factors, such as increasing sea water temperatures. Previous studies of the effects of temperature changes on coral physiology and associated bacterial communities have been conducted based on stable water temperatures set by mean temperatures, or by slowly increasing/decreasing temperatures. However, the daily temperature fluctuations that corals experience in nature are not stable. The current understanding of the effects of large daily temperature fluctuations on coral and associated bacterial community dynamics is limited. Hence, we conducted a four-week tank experiment using different large daily temperature fluctuations (+/- 5 degree celsius and +/- 7 degree celsius) accompanied by continuous warming conditions (26 degree celsius to 29 degree celsius) to investigate the effects on two common reef-building corals, Stylophora pistillata and Pocillopora acuta. During the experiment, the activity of coral host catalase and superoxide dismutase were measured, the photosynthetic ability of symbiotic algae was recorded, and the variation in bacterial communities was analyzed using the V6-V8 region of 16S rDNA. According to the results, different parts of the holobionts of two coral species exhibited varying response rates to the continuous warming conditions and diurnal temperature fluctuations. Additionally, it was found that diurnal temperature fluctuations may mitigate the heat stress on the host and reduce the changes in bacterial response to warming. Therefore, it is suggested that the holobionts of different coral species may adopt different adaptation and survival strategies in response to diurnal temperature fluctuations and warming. Finally, based on the response of these two coral species under the conditions of diurnal temperature fluctuations and continuous warming, Acinetobacter and Rhodobacteraceae were identified as potential indicator coral-associated bacteria. This is the first study to investigate the tripartite dynamic response of coral, symbiotic algae and bacteria to daily temperature fluctuations.2024-01-01T00:00:00ZPossible germline progenitor cells in extra-gonadal tissues of the sea anemone, <i>Exaiptasia diaphana</i>
http://scholars.ntou.edu.tw/handle/123456789/24672
標題: Possible germline progenitor cells in extra-gonadal tissues of the sea anemone, <i>Exaiptasia diaphana</i>
作者: Shao, Pei-Jung; Chiu, Yi-Ling; Tsai, Pin-Hsuan; Shikina, Shinya
摘要: Many anthozoans, e.g., sea anemones and corals, have remarkable capacities for asexual reproduction and regeneration, creating complete individual polyps from pieces of parental polyp tissue. Notably, polyps produced asexually (or regenerated) from somatic tissues that originally contain no gonads are capable of sexual reproduction. However, how somatically derived polyps can reproduce remains largely unexplored. Here, using a sea anemone, Exaiptasia diaphana, we show that potential germline progenitor cells are present in the extra-gonadal tissues, and that they are allocated to newly produced individuals during asexual reproduction/regeneration. Histological analysis of E. diaphana demonstrated that polyps asexually produced from pedal lacerates can create mature gametes. Amputation experiments showed that polyps regenerated from the head, which originally lacked gonadal tissue, formed gonads and initiated gametogenesis. Immunohistochemical analysis with a germline marker, vasa, demonstrated the presence of vasa-positive cells in various polyp tissues. These findings suggest that vasa-positive cells in extra-gonadal tissues may be a reservoir of germline progenitor cells to ensure sexual reproductive capacity in individuals produced asexually or regenerated from somatic tissues.2023-01-01T00:00:00ZSeasonal Patterns of Picocyanobacterial Community Structure in the Kuroshio Current
http://scholars.ntou.edu.tw/handle/123456789/24580
標題: Seasonal Patterns of Picocyanobacterial Community Structure in the Kuroshio Current
作者: Chan, Ya-Fan; Chung, Chih-Ching; Gong, Gwo-Ching; Lin, I-Jung; Hsu, Ching-Wei
摘要: The nutrient-scarce, warm, and high-salinity Kuroshio current has a profound impact on both the marine ecology of the northwestern Pacific Ocean and the global climate. This study aims to reveal the seasonal dynamics of picoplankton in the subtropical Kuroshio current. Our results showed that one of the picocyanobacteria, Synechococcus, mainly distributed in the surface water layer regardless of seasonal changes, and the cell abundance ranged from 104 to 105 cells mL-1. In contrast, the maximum concentration of the other picocyanobacteria, Prochlorococcus, was maintained at more than 105 cells mL-1 throughout the year. In the summer and the autumn, Prochlorococcus were mainly concentrated at the water layer near the bottom of the euphotic zone. They were evenly distributed in the euphotic zone in the spring and winter. The stirring effect caused by the monsoon determined their distribution in the water column. In addition, the results of 16S rRNA gene diversity analysis showed that the seasonal changes in the relative abundance of Synechococcus and Prochlorococcus in the surface water of each station accounted for 20 to 40% of the total reads. The clade II of Synechococcus and the High-light II of Prochlorococcus were the dominant strains in the waters all year round. Regarding other picoplankton, Proteobacteria and Actinobacteria occupied 45% and 10% of the total picoplankton in the four seasons. These data should be helpful for elucidating the impacts of global climate changes on marine ecology and biogeochemical cycles in the Western Boundary Currents in the future.2023-11-01T00:00:00ZCellular and Biochemical Changes in Early Embryonic Development of a Scleractinian Coral,<i> Fimbriaphyllia (Euphyllia) ancora</i>
http://scholars.ntou.edu.tw/handle/123456789/24571
標題: Cellular and Biochemical Changes in Early Embryonic Development of a Scleractinian Coral,<i> Fimbriaphyllia (Euphyllia) ancora</i>
作者: Shikina, Shinya; Chiu, Yi-Ling; Chung, Yi-Jou; Yao, Yi-Chen; Liu, Tai-Yu; Lee, Yan-Horn; Mita, Masatoshi; Chang, Ching-Fong
摘要: Knowledge of early life histories of scleractinian corals is essential for ecological studies (e.g., larval dispersion and connectivity) and development of aquaculture techniques. The present study documents cellular and biochemical changes during early development of a scleractinian coral, Fimbriaphyllia ancora (Order Scleractinia, Family Euphyllidae). Observations of spawning revealed that F. ancora releases positively buoyant eggs. No fertilization membrane surrounded fertilized eggs, which developed into swimming planula larvae within 48 h after fertilization. Lipid content analysis showed that eggs are rich in wax esters, and that the wax ester concentration decreases significantly in planulae. Sugar content analysis revealed that the eggs are also rich in glycogen, and that the glycogen concentration increases as development progresses. Free glucose was not detected in samples that we analyzed. Moreover, a settlement assay showed that F. ancora planulae prefer to settle on dead coral debris, compared to other substrate materials, such as plastic, microscope slides, ceramics, and crustose coralline algae.2023-08-11T00:00:00Z