愛的教育,鐵的紀律-果蠅的學習與記憶
The main purpose of this study is to explore whether fruit flies (Drosophila melanogasters which background is 2U) can distinguish and memorize different colors and smells by learning. Futhermore, to find out the relation between age and learning ability, and analyze the influence of repeated training on how long the memory would last. According to our experiment, in smell training, the fruit flies are able to distinguish and memorize different smells, and young fruit flies have better memory than old flies. In color training, the fruit flies can distinguish and memorize different colors, but the effect was less than that of smell training. In intensive learning, proper times of learning increased the memory ability, but excessive learning exhibited an opposite effect. In the labyrinth experiment, we select and nurture the fruit flies having the best color memory in order to further understand the gene correlated with the memory learning. In addition, in one-time training, fruit flies are able to remember the smells and colors in four minutes, and young ones have the better ability. In six-time training, fruit flies have the ability to remember the smells and colors in twelve minutes. In the end, we hope you can know more about the learning and memory ability of fruit flies through our report. 本實驗主要探討果蠅是否可經由學習分辨、記憶顏色與氣味,並探討年齡與學習能力的相關性、分析多次訓練對記憶時間的影響。由實驗結果得知,氣味方面,果蠅有辨識記憶氣味的能力,以年輕果蠅的效果較佳;顏色訓練方面,果蠅亦可分辨記憶顏色;密集學習方面,適當學習次數內,有助於增加果蠅的記憶能力,但過度的學習刺激會降低學習效果。並且,我們選顏色訓練中記憶較佳的一組進行迷宮實驗,經三次的岔路選擇,選出對顏色記憶最佳的果蠅,希望能探討訓練過的果蠅子代能否有較優良的記憶。至於記憶時間方面,一次氣味學習,果蠅在四分鐘內皆有記憶,且年輕果蠅記憶效果較強,達六分鐘;另外,多次氣味學習,果蠅於第四次訓練效果最佳,且記憶能力可達十二分鐘。希望藉本實驗報告,以期更瞭解果蠅學習與記憶的資料。
黑龍仔知人間冷暖
為了瞭解黃斑黑蟋蟀叫聲和溫度之間的關係,我應用物理熱平衡原理,自製水浴槽控制環境溫度,以電腦錄音程式分別錄製15℃、20℃、25℃、30℃、35℃時的蟋蟀叫聲,利用Sound Forge軟體分析並比較不同溫度下的各種特性。結果發現所分析的chirp、chirp period、syllable period、pause均和溫度呈負相關,而單位時間內的叫聲次數則與溫度成正相關,並推導出15~35℃範圍內蟋蟀叫聲次數與溫度成正相關的公式。最佳直線為:﹙15秒內叫聲次數+19.385﹚÷2.483=當時溫度﹙℃﹚,呈高度正相關﹙相關係數:0.9398﹚。本實驗也比較母蟋蟀對不同溫度下雄蟋蟀叫聲的偏好程度,發現母蟋蟀較偏愛25℃時的雄蟋蟀叫聲,此結果可能與雄蟋蟀在25℃時叫聲的波形最為穩定有關。為探測蟋蟀觸角上的溫度感受器位置,我們曾將不同部位的觸角加以剪除,結果顯示觸角剪除面積越大的雄蟋蟀越不傾向鳴叫,但無法證實是否為溫度偵測異常所導致。本實驗除供學術研究外,因黃斑黑蟋蟀在世界各地均有分布,所以希望能藉由分析溫度與蟋蟀叫聲的相關性實驗,未來嘗試能探討其在不同環境的適應行為亦或種化的可能性。另外,全球暖化問題日益嚴重,也希望能藉由相關實驗探討暖化對蟋蟀生態上的影響。最後,我們的實驗證明了蟋蟀叫聲和環境溫度確實有極大的關聯性,未來或許能參考蟋蟀感覺溫度的機制,製作出一個天然零污染的溫度計。 To find out the relationship of cricket’s calling and temperature, we use a hand-made water-bath tank to control the temperature and record the callings with microphone and software, Sound Forge. After analyzing the collected data, we’ve found that cricket’s chirp, chirp period, syllable period, and pause are indeed affected by temperature (15 degrees - 35 degrees C). Moreover, we also compare female cricket’s preference to the callings, and the result indicates that female cricket’s preference is changing with temperature. In the last, we tried to find out where the thermoreceptors are by cutting out the antennae. After cutting, crickets tend to not to make any calls at all, so we conclude the antennae might play an important role in sensing and calling. The experiment proves that this communication system is temperature coupled. Because the cricket, Gryllus bimaculatus, is a worldwide species, we may learn the accommodation or the possibility of performing a new species by researching the relationship of temperature and cricket’s callings. By the way, the Green House Effect is getting more and more serious, so we want to search for the influences on crickets that are caused by Green House Effect. The last but not the least, according to the report, maybe we can investigate the mechanism of sensing temperature and then make a natural thermometer that is no pollution in the future.
丹尼爾寶寶的酗酒日記--酒精對斑馬魚胚胎頭骨與腦下垂體基因的影響
長期以來,臨床研究發現酒精會影響人類胚胎的正常發育,但是其分子機 制尚不清楚。在本研究中利用RNA 定位雜交的方式觀察酒精對於胚胎發育過程 中shh、sox9a、sox9b、col2a1、hand2 的影響,發現這些基因的表現均會受到酒 精的抑制。這項結果顯示在胚胎發育過程中,酒精透過對上述基因的影響,造成 神經脊細胞減少,細胞遷移異常,以及干擾軟骨細胞分化的現象,進而造成頭骨 發育的嚴重缺陷。此外,實驗中亦發現生長激素在腦下垂體的表現亦受到酒精抑 制。這項研究的結果成功地從基因的層次深入了解胎兒酒精中毒症候群造成頭骨 畸形及生長遲緩的病理機制。 It was known that prenatal alcohol exposure may cause serious birth defects and developmental disabilities. The molecular mechanism of this fetal alcohol syndrome still remains unclear. As revealed by whole mount RNA in situ hybridization, it was shown that expression of a number of craniofacial cartilage-related genes, including shh, sox9a, sox9b, col2a1 and hand2, were all inhibited in zebrafish embryo by alcohol exposure. It suggests that alcohol exposure may result in reducing neural crest cell production, interfering neural crest migration, preventing chondrogenesis and eventually cause craniofacial defects. In addition, the transcriptional profile of pituitary hormones were investigated by RNA in situ hybridization. It appears that only growth hormone, but not prolactin and thyroid stimulating hormone, was inhibited by alcohol exposure. The reduction of growth hormone transcription was also confirmed by real time PCR. It also appears that the expression of upstream transcription factor pit1 and downstream target gene igf1 remains unchanged. It suggests that the reduction of gh transcription is mediated by a PIT1-independent pathway. The transcriptional profile of alcohol-exposed embryo was investigated by gene microarray analysis. It appears that the expression profiles of a number of development, cellular signaling, cell growth and apoptosis related genes have be affected by 1.5% alcohol treatment. It was noted that a number of retinal-specific genes were all repressed significantly. It consists with histochemical observation that alcohol exposure results in loss lamination and disturbed differentiation. This study help us understanding the molecular mechanism of fetal alcohol syndrome.
斑馬魚 SULT2 ST2在早期胚胎發育的 RNA 表現
在哺乳動物裡,硫酸化是一種參與外來物解毒作用、內生組織的荷爾蒙調節、藥物代謝及膽汁解毒之重要路徑。其中, SULTZ ( hydroxysteroid sulfotransferase )是能進行上述反應的酵素之一,為了對 SULTZ 的功能與早期發育所扮演的角色作進一步的研究,在本實驗中,我們以班馬魚為模式動物,希望藉由原位雜交法( in situ hybridization )找到 SULTZ 在班馬魚早期胚胎發育的 RNA 表現位置。由目前的實驗結果,發現從卵巢到1-cell、 dome 、 50 %一 epiboly 、 12 小時,都可在胚胎細胞看到訊號表現 · 在 24 小時、 36 小時、 48 小時、 72 小時則可在脊椎兩側體節的肌肉、內胚層、嗅窩、頭部看到訊號表現,此外,在成腦的原位雜交染色結果中亦看到了訊號表現。由此可推論 SULTZ 在斑馬魚早期發育確實扮演了重要的角色。Sulphonation is an important pathway for detoxification of xenobioties, bile acids, drug metabolism, and the regulation of endogenous hormones. SULT2 (hydroxysteroid sulfotransferase) is one of the enzymes which catalyse sulphonation. Zebrafish has emerged as a popular animal model in recent years. Compared with other vertebrates, it provides advantages including ease to get embryos, rapid external development, virtually transparent embryos and ease of genetic manipulation. The above-mentioned strong points made zebrafish a good model animal for us to understand the function of SULT2 during early embryonic development. We performed in situ hybridization to find out the RNA expression of SULT2 during zerbrafish early development. According to our present results, we can detect expression signal on the edge of telencephalon and tectum opticum. the edge on the dorsal zone of corpus cerebelli and ventral zone of periventircular hypothalamus of the adult brain. Besides, we can observe signal evenly distributed in blastocytes of the embryo at 1-cell, dome. 50%-epiboly and 12 hours after fertilization. We also find signal on the muscle next to the spinal cord during the stages of 24, 36, 48 and 72hrs. There are also expressions on hypoblast of embryos at 24, 36 and 72hrs, the olfactory pit at 36 and 4hrs, and strong expression in head region at 48 and 72hrs. These results suggest that SULT2 may have some function at the early development of zebrafish.
人面蜘蛛藉調整絲基因表現及網結構促進捕食效率
前人研究顯示結網性蜘蛛會因環境中獵物組成的改變而改變其網結構。然而,除了結構之外,構成網的絲的物理性質與蜘蛛網的捕捉效率也應有密切之關連,但目前並無人探討蜘蛛是否會因獵物而調整絲之化學及物理性質。在本研究中,我以人面蜘蛛為材料,探討:(一)其在面對不同類型之獵物時是否調整其網之結構,絲之胺基酸組成和其物理性質;(二)所產生之改變是否能促進不同類型獵物的捕食效率;以及(三)是獵物之養份或振動刺激引起這些改變。我藉著操控獵物的養份及振動刺激將人面蜘蛛分成四個處理組,分別餵以活蟋蟀(C 組),活蒼蠅(F 組),死蟋蟀加蒼蠅振動刺激(Cd 組)及死蒼蠅加蟋蟀振動刺激(Fd 組)。在完成食控處理後比較各組間之網結構、絲胺基酸組成、絲物理性質、對不同獵物之留置能力以及振動訊號傳遞能力。實驗結果顯示F 組之蜘蛛所結之網有較大的面積及較小的網目,並有較佳之蒼蠅留置力;然而此結構之改變卻會降低其振動訊號傳遞率。C 組之蜘蛛所結之網有較強之張力及較佳之蟋蟀留置力,而且其所產之曳絲有較高比例之alanine、glycine 及glutamine 並較佳之延伸度及韌度,以因應體型較大之獵物。上述結果顯示人面蜘蛛能調整網的結構、絲的蛋白質組成及物理性質來更有效率的捕捉不同類型的獵物。而由於上述各樣變數在C 及F 組間有顯著差異,而在獵物養份與振動訊號錯置的Cd 與Fd 組間無顯著差異,顯示此二項刺激需同時存在才能使人面蜘蛛在面對不同類型獵物時產生結網行為及絲基因表現之改變。Previous studies showed that orb-weaving spiders may adjust web structures when encountering different types of prey. In addition to web structures, silk physical properties should also be critical in affecting the prey catching efficiency of webs. However, so far no one has studied whether spiders adjust silk chemical and physical properties when encountering different types of prey. In this study, I used the giant wood spider Nephila pilipes to investigate (1) would N. pilipes adjust web structures, silk amino acid composition and silk physical properties when encountering different types of prey (2) would such changes enhance the catching efficiency of different prey and (3) were such changes generated by prey chemical composition or vibration signals? To answer these questions, I manipulated prey chemical composition and vibration signals by assigning N. pilipes into the following four feeding groups: (1) living crickets (group C), (2) living flies (group F), (3) dead cricket but with fly vibration signals (group Cd) and (4) dead flies but with cricket vibration signals (group Fd). After the feeding treatments were completed the following variables were compared between the feeding groups: web structures, silk amino acid composition, silk physical properties, retention time of different prey and vibration signal transmission rate of webs. The results showed that the webs built by spiders fed with living flies exhibited larger area, smaller mesh and longer fly retention time. However, such structural changes also reduced the vibration signal transmission ability of the web. On the other hand, webs built by spiders fed with living crickets were stiffer and retained crickets longer. Moreover, their silks exhibited higher percentages of alanine, glycine, glutamine and consequently higher elasticity and strength to cope with the larger prey. These results demonstrated that spiders can adjust web structures, silk protein composition and silk physical properties to enhance the catching efficiency of different prey. While the aforementioned variables differed significantly between spiders in C and F groups, they did not vary between spiders in Cd and Fd groups, in which groups the prey chemical composition and vibration signals were decoupled. Such result suggested that prey chemical composition and vibration signal were both needed in generating changes in web building behavior and silk gene expression in spiders.