全國中小學科展

微生物學

Co-evolution of transcription factors and their binding sites in DNA

The synthesis of RNA using DNA (transcription) can be regulated by special proteins - transcription factors (TF) by binding to specific DNA regions - binding sites (BSTF). The purpose of the project is building a phylogenetic tree of orthologous groups of the each studying TF subfamilies, compare it with the tree of the corresponding BSTF motifs belonging to one orthologous group, find some common parts.

Algae Meets Fungi: Microalgae-Fungi Co-Pelletization for Biofuel Production

Microalgae-fungi biofuel has significantly less CO2 emissions than fossil fuels, making it much more environmentally friendly. As well, unlike traditional biofuel, microalgae-fungi does not require large masses of agricultural land for production. Thus, microalgae-fungi is an optimal option for biofuel production. This is a cost-effective renewable energy source that can be used in place of regular gas in cars and other means of transportation. By determining the most effective fungi for biofuel production, the threat of the impending environmental damage from pollution can be diminished. This novel experiment determines which fungi: Aspergillus niger, Rhizopus stolonifer or Saccharomyces cerevisiae, is the most effective bioflocculant in the microalgae-fungi co-pelletization process for biofuel production. We hypothesize that when paired with the microalgae Chlorella vulgaris, Rhizopus stolonifer will be the most effective. It has a high lipid content which could enhance the overall production of biofuel. Furthermore, its negative charge will aid with attracting and neutralizing the C. vulgaris colloidal particles resulting in an easier and more efficient removal of microalgae particles. Through the process of bioflocculation, pelletization, esterification and transesterification, the most effective fungi paired with C. vulgaris was determined. This experiment was carried out thoroughly and precisely resulting in a cost-effective solution for the world's current pollution crisis.

利用共生菌與小球藻建構不須添加培養基且能日夜發電的長效生物光伏電池

¬生物光伏電池(BPV)是一種利用光合自營生物進行光電能量轉換的發電裝置。本研究利用共生菌G76創造不須補充培養基的固態複合型BPV。我們以陽極只含小球藻的BPV為控制組(X-C),發現在實驗開始24小時之後,BPV電壓開始隨著光照週期產生規律變化,前三個光週期電壓高峰平均值為116.23±2.92 mV, 谷底平均值為87.96±4.48 mV,波動幅度28.27 mV。實驗組為陽極有小球藻與共生菌G76的複合型BPV (X-CG),同時期電壓高峰平均值為109.23±2.45 mV, 谷底平均值為100.63±0.9 mV,波動幅度8.6 mV。與X-C相比,添加G76會使電壓高峰下降6.02%,但提高谷底電壓14.4%且縮小電壓波動幅度69.58%。目前X-CG已運轉超過1032小時,電壓高峰為95.2mV,衰減幅度19.35%。同時期控制組X-C電壓高峰已下降至61.1mV,衰減幅度90.22%。實驗過程中我們發現在X-C及X-CG組別運作73小時後, 在陰極區都出現了紫黑色微生物(PB1),同時這些被汙染的BPV的電壓明顯比其他組別更高,將BP1單獨培養並引入陰極後(P-CG), 此一BPV的電壓高峰平均值高達179.3±3.66 mV,谷底平均值則為162.37±1.38 mV,都比X-CG組提高近六成。更重要的是X-CG與P-CG分別能保持日間電壓的92.13%與90.56%,都是非常穩定的BPV。 由以上結果可知, 將共生菌G76加入BPV陽極能提高日夜間的供電穩定度並延長裝置使用壽命,而將PB1引入陰極則能使BPV電壓提高六成以上。若能進一步優化應用這些共生菌, 此種低成本複合型生物光電轉換裝置將有潛力建構出一套不須儲電系統的太陽能發電系統。

Machine-learning assisted antibiotic detection and categorization using bacterial arrays

隨著抗生素的廣泛使用,抗生素殘留的問題日益嚴重。為此,本研究建立了一個稱作細菌陣列固相分析(BacSPA)的方法來檢測和分類樣品中的抗生素。本研究將15個在質體中植入生物冷光的大腸桿菌液,點在與11種不同的抗生素混合的固相培養基上,濃度為1.5 ppm。不同的抗生素會刺激細菌,使其產生特定的生物冷光變化圖形。將圖形以延時攝影紀錄,並以機器學習演算法中的多重決策樹系訓練抗生素分類模型。得到的最佳模型能在三小時內,以90%分類抗生素的類別。再對該方法進一步測試,以區分不同濃度的抗生素。最終模型能將濃度從125 到1000 ppb的八種抗生素進行分類,其準確率大多高於70%。在未來,我們希望能建立更多不同濃度、不同組合的抗生素發光圖形資料庫,以擴大此方法的應用範圍。這無疑為人們檢測與分類食品與環境樣品中的抗生素殘留,提供了一個很好的方法。

以線蟲模型探討核醣核酸結合蛋白MSI-1如何影響微小核醣核酸let-7調控lin-41路徑

癌症是世界性的嚴重疾病,長年位居國人十大死因之首。而基因調控的失控是造成癌症的主要原因之一,由先前的文獻已知,微小核醣核酸let-7負向調控下游基因lin-41是調控細胞週期及癌症發展和預後的重要路徑。由於此調控路徑具有演化上的保守性,本研究以較易操作實驗的秀麗隱桿線蟲為生物模型,透過RNAi 的方式,降低特定基因的表現,觀察是否影響與let-7/LIN-41調控路徑相關的突變性狀,來推測該基因是否參與此路徑相關之細胞週期調控。 本研究中,我們發現以RNAi降低核糖核酸結合蛋白msi-1的表現量可抑制let -7(n2853) 突變種線蟲中因let-7功能缺失所造成的接縫細胞的重複分裂的突變性狀,並增強對下游基因col-19的活化調節。我們推論,降低msi-1表現量可以提升let-7路徑的功能。我們期望可以藉由研究msi-1如何調控此路徑的機制,更加了解MSI-1此一核糖核酸結合蛋白對於細胞週期的控制,並提供未來癌症標靶藥物的重要參考。

菌菌有味—真菌及塔粉綠尺蛾幼蟲食草選擇之探討

本研究主要探討塔粉綠尺蛾食草選擇與其葉內真菌之關係。觀察培養四種植物(烏臼、鵝掌柴、白匏子與島榕)葉內真菌,以真菌生長率、菌絲與孢子形態辨識真菌種類。當我們以烏臼葉內間座殼菌屬(Diaporthe sp.)真菌與不同植物放在一起時,幼蟲取食原為非食草的白匏子葉片,而島榕則有嘗試啃食之現象;此外,飼養過程中我們發現取食烏臼的塔粉綠尺蛾幼蟲糞便較其他種幼蟲易長出真菌,進行幼蟲糞便與消化道真菌培養後,皆有與葉內真菌相似的菌體形態。我們推測烏臼、葉內真菌與塔粉綠尺蛾間的交互作用關係之一可能為:烏臼透過葉內真菌誘使塔粉綠尺蛾雌蛾前往產卵,經幼蟲食用葉片後所排出之糞便以作為葉內真菌傳播的媒介。

Solar Powering Day and Night with Boxed Micro-Biosphere

本研究在生物光伏電池(Bio-photovoltaics, BPV)的陽極添加能氧化含氮廢物放出電子的硝化菌,並在陰極添加能吸收電子還原硝酸鹽與硫酸鹽產生氮氣與硫化氫的厭氧菌,建立不需外部供給物質,能夠自我維持且不斷發電的微型生態圈(Boxed Micro-Biosphere, BMB)。實驗結果顯示在陽極加入硝化菌後,能使含小球藻與共生菌Sym1的BMB功率提升38倍至99.46±9.31μW · m-2,而在陰極加入厭氧菌能讓功率再提升至262.51±37.30 μW · m-2,且此電池截至目前為止已運轉超過4272小時,發電功率仍保有67.4%(176.98 μW · m-2)。若將Sym1與Sym2同時加入陽極則可使功率密度提高至463.19±25.50 (μW · m-2),夜間功率可達白天的93.1%,但在野外實驗環境下一週內就失去發電能力。若將BMB中小球藻換成來自高溫與強酸環境的溫泉藻(H),其野外平均功率為388.80±14.87 μW · m-2,夜間發電量為白天97.9%,其功率與壽命(目前尚在運作中)遠高於小球藻BMB。 未來我們將篩選能加強溫泉藻發電能力的共生菌使其更具實用性。

探討芽孢桿菌FZB42對植物病原菌拮抗之分子機制

植物病原菌為造成台灣農業生產損害的一大威脅,近年來隨環保意識抬頭,生物防治更顯重要。本研究旨在探討芽孢桿菌FZB42 (Bacillus velezensis FZB42)中,影響對植物病原菌拮抗作用的基因序列,主要選取馬鈴薯瘡痂病菌(Streptomyces scabies PS07)做為本研究植物病原菌的受試對象。 研究中以跳躍子TnYLB-1隨機插入FZB42之基因體,破壞基因的表現能力,並以對峙培養實驗(dual culture experiments)分析其對植物病原菌的抑制圈半徑大小,觀察其拮抗效果的變化,後續以反向聚合酶連鎖反應(Inverse PCR; iPCR)技術確認跳躍子插入所破壞的基因序列,進而探求其對於植物病原菌拮抗的分子機制。 本研究初步篩選出五株FZB42突變株(mutant),於對峙實驗中分析得知其對S. scabies PS07的拮抗效果較FZB42野生株顯著降低,推測該突變株內受跳躍子插入破壞的基因與其拮抗作用相關。再透過iPCR確認該基因的序列,經資料庫比對,推論此基因最有可能為「可產生蛋白質LoaP以促進菌體內基因簇(difficidin gene cluster)產生抗細菌物質的基因」或「藉光遺傳學控制調控菌體生長的基因」。本研究探究FZB42拮抗病原細菌S. scabies PS07的機制,得證抗細菌基因與芽孢桿菌FZB42拮抗馬鈴薯瘡痂病菌Streptomyces scabies PS07之分子機制具有一定關聯性。 期望透過本研究對此拮抗機制的結果,應用於抑制馬鈴薯瘡痂病菌對作物的威脅,提供未來生物防治領域的參考。

利用次世代基因定序技術探討我國急性腹瀉患者之腸道菌叢表現

依據世界衛生組織2013年調查研究顯示,全球每年約有29%的孩童 (超過兩百萬名) 因腹瀉及肺炎而死亡,而在我國腹瀉群聚亦佔傳染病防治之大宗,尤其2020年受新冠肺炎(COVI-19) 疫情影響,台灣民眾均留在國內旅遊,腹瀉案件急速增加,且因適逢旅遊熱門旺季加上中小學開學之際,經常出現規模上百人的腹瀉群聚,危害民眾健康。現階段急性腹瀉病人的治療多以支持性療法為主,然而目前應用糞便移植重建腸道菌叢已是包括癌症在內的重症醫療方向之一。本研究應用次世代基因定序技術偵測微生物16S rRNA 的高變異區域進行急性腹瀉患者腸道微生物菌相組成、菌種豐富度分析及菌種鑑定,希望透過偵測急性腹瀉患者的腸道微生物相分析有助於理解腹瀉患者與健康人體腸道菌叢的差異,可提供未來臨床治療參考,亦可藉此推動從家庭到社區的全民健康促進,打造健康優質的生活品質。

Expectations for extension of cell life and next generation anticancer drugs by using secondary metabolites of actinomycetes

Inhibitory effects of the secondary metabolite of actinomycete were examined on cell cycle of the yeasts of S. pombe and S. cerevisiae. The secondary metabolite was obtained from cultivation of the actinomycete isolated from the soil of Owakudani in Hakone, Japan. The fifth fraction of the secondary metabolite by ODS column separation (HK-T5), which was soluble to pure methanol, was used in the present experiments. The HK-T5 brought about the delay of forming colonies of S. pombe for about 11 days compared to that cultivated without the HK-T5. The delay of the colony formation was longer for the S. pombe cultivated with more amount of the HK-T5. The cultivation with HK-T5 also brought about the extension of the lifespan of the S. pombe for more than 10 weeks in a liquidus medium. The cell life recovered the ordinary manner by removal of the HK-T5, meaning that the activities of the HK-T5 is reversible. These facts confirm the suppression of cell cycle, and the delay of cell growth by the HK-T5. These phenomena were similarly observed for S. cerevisiae. Comparison of the action of HK-T5 with hydroxyurea, which is an anticancer drug inhibiting the cell cycle at S phase, clarified that the inhibitory action of HK-T5 worked at the phase earlier than S phase. The combined effects of HK-T5 on the cell cycle were evaluated with triamcinolone acetonide (TA), or aspirin, the former of which is a drug synchronizing cancer cells in S phase, and the latter keeping human cells in G1/G0 phases. The combined use of HK-T5 with TA synchronized the cells at the phase slightly proceeding from G1 to S phase without toxicity. On the other hand, the combined use with aspirin made the inhibitory effect of HK-T5 inactive. Hence, the HK-T5 is attractive as a drug for the extension of cell lifespan, and anticancer therapy.