全國中小學科展

動物學

The Population Structure of the Orange River mudfish (Labeo capensis) in Allemanskraal Dam and Its potential as a Fishery Species

The aim of this research was to investigate whether the ecology and biology of the Orange River mudfish Labeo capensis were suitable for the species to be used in fisheries. Three fleets of the gill nets were set, parallel to the shore. One fleet was lifted, and the fish were collected by hand. The two remaining fleets were lifted the next day. The seine net was pulled for 10 metres within the littoral zone. The net was then pulled towards the shore of the dam and the procedure was repeated four times. The four fyke nets were set parallel to the shore and were left for two nettings nights and then lifted. All fish caught were collected by hand and placed into buckets. The majority (82.93%) of the fish caught were within the 0-100 mm size class. The 101-200mm and 201-300mm size classes contain similar numbers of fish, while no fish were caught in the 301-400mm size class. The hypothesis was accepted. Allemanskraal Dam, as of the study period, has a very small juvenile fish population of L. capensis, as only 7 out of 41 fish individuals caught were within the 101- 300mm fork length size class. These results show that the population of L. capensis is not established as of yet, as the research did was right after their breeding season. Historical research has shown that sexually mature individuals of the L. capensis species tend to be a minimum of 300mm SL, 4-6 years after hatching. The population was largely young-of-the-year and may develop into an established population in 3-4 years (after sexual maturity). The L. capensis population in Allemanskraal Dam has the potential to be a fishery species if suitable conditions are maintained. Establishing this species’ potential will therefore allow economically viable fisheries to utilise them sustainably and to their full economic potential.

魚類在面對酸逆境下醣類的代謝差異

溫室氣體產生造成環境變遷,使得水質酸化,進而影響生態系統。生存在水中的魚類,為了適應水質的酸化,他們的生理上必定有一些變化。為了找出魚類適應酸化環境所做出的改變,我們選擇以斑馬魚及青鱂魚做為實驗動物以研究水質酸化對於其代謝之影響,分析其中與能量代謝及合成相關的器官,包含消耗大量能量的以維持酸鹼平衡的鰓、能量供應相關的肝臟和肌肉。綜合即時聚合酶連鎖反應及免疫螢光染色的結果,我們發現斑馬魚在面對酸性環境下時醣類代謝的情形是有改變的,肝臟內肝醣分解及糖質新生的效率提升,且鰓部位醣類代謝效率提升,推測是運送葡萄糖給鰓部位進行排酸代謝,其鰓部位細胞內的酵素也因此出現了細胞分工的現象。而青鱂魚在面對酸性環境下時,透過肝醣分解提供更多的葡萄糖進行糖解作用,同時抑制了糖質新生反應效率,推測其演化出了高效率的排酸方法。相較於斑馬魚,青鱂魚醣類代謝不會產生過多的能量,也意味著青鱂魚能量使用效率有提升。

在壓力下更要堅強,探討ACE2/Ang(1-7)軸與韌力的關係

背景:韌力 (resilience)指個體遭受壓力時快速調適及復原的能力,是許多疾病的保護因子但生理機轉仍不明。Angiotensin-converting enzyme 2/Angiotensin(1-7) [ACE2/Ang(1-7)]軸具有保護心血管、抗焦慮及保護神經的潛力。目前仍無ACE2/Ang(1-7)軸與韌力相關的研究。另外ACE2是SARS-CoV-2病毒進入人體的受體,相關研究在疫情下更顯重要。 目的:本研究中我們以習得無助行為模式篩選具韌力行為的大鼠(resilient, R),探討韌力鼠與非韌力鼠(non-R) ACE2/Ang(1-7)軸表現的差異。 假說:韌力鼠的ACE2/Ang(1-7)軸活性較非韌力鼠高。 結果:韌力鼠在壓力下其corticosterone (CORT)濃度與控制組無差異。韌力鼠的Ang(1-7)濃度較非韌力鼠及控制組高,暗示較高的Ang(1-7)濃度與韌性表現相關。以Ang(1-7)/Angiotensin II (Ang II)比率作為反映ACE2 轉化Ang(1-7) 功能的指標,發現韌力鼠的ACE2濃度及功能均與未主動逃跑而受電擊的時間相關,暗示其ACE2活性能因應壓力調控上升。韌力鼠的ACE2濃度雖較非韌力鼠低,但其ACE2功能則較其他兩組高。並且,Ang (1-7)濃度及ACE2功能僅在韌力鼠與ACE2濃度呈現正相關,但在非韌力鼠則無相關。暗示在壓力下韌力鼠的ACE2仍維持有效率的功能但非韌力鼠的ACE2功能則受影響。另一方面,Ang (1-7)濃度僅在非韌力鼠與CORT濃度負相關,暗示非韌力鼠個體的ACE2/Ang (1-7)]軸活性與海馬迴-下視丘-腦下垂體(HPA)軸的活性可能相關。 結論:韌力個體的ACE2/Ang (1-7)軸活性較非韌力鼠及控制組佳且可能因應壓力而調節增加。相反的,非韌力鼠個體的ACE2/Ang (1-7)軸功能較差且可能與HPA軸的活性相關。我們的研究顯示ACE2/Ang (1-7)軸扮演調節韌力的重要角色。ACE2/Ang (1-7)軸活性是否可以做為個體韌力的指標或具有增進韌力的臨床價值需進一步研究。

Super「鼠」跑

透過文獻探討已知高血壓會引起腦發炎,導致腦功能受損。研究結果也顯示運動能增進腦部功能。因此,在此實驗中,我們想要探討高血壓引起的腦發炎和功能退化等問題能否透過運動改善。將鼠分為 2K1C 手術誘發高血壓組(2K1C)及沒有高血壓(Sham)的對照組,並再各分為運動組(Sham-EX、2K1C-Ex)和不運動組(Sham、2K1C)。小鼠腦部切片中微小膠細胞數量顯示 2K1C 的小鼠組別腦發炎最為嚴重,且 HE 染色發現一樣為 2K1C 小鼠組別的神經細胞數目最少。接著我們以莫里斯水迷宮測試小鼠學習、記憶功能,結果 Sham-Ex 及 2K1C- Ex 尋獲平台時間皆有減少趨勢,而 2K1C 尋獲平台花費最長時間,顯示運動確實可以減緩高血壓造成的腦功能受損。