本文選題：納米二氧化鈦　切入點(diǎn)：果蠅　出處：《南京農(nóng)業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：近年來,納米科技的興起與快速發(fā)展使得納米材料被廣泛應(yīng)用于人們的日常生活中,目前納米二氧化鈦被認(rèn)為對人體無毒性,已被應(yīng)用于空氣和水的凈化,食品包裝,防曬化妝品的生產(chǎn)等諸多方面。納米二氧化鈦的應(yīng)用之廣,使得它很容易隨飲食、空氣、水進(jìn)入人體腸道,而人體腸道內(nèi)共生著大量的腸道菌群,這些正常的共生菌群在宿主能量與代謝平衡中發(fā)揮著重要作用,一旦失調(diào)有可能影響宿主身體健康,導(dǎo)致疾病的產(chǎn)生。二氧化鈦的光催化殺菌作用已被應(yīng)用于實(shí)踐,納米二氧化鈦一旦進(jìn)入人體,在接觸不到光照的情況下會對腸道菌產(chǎn)生怎樣的作用,以及對人體造成怎樣的毒副作用亟需研究。果蠅作為生物實(shí)驗(yàn)的模式生物,有著與哺乳動物相同的保守信號通路,且果蠅腸道共生菌種類數(shù)量較少,方便研究。實(shí)驗(yàn)室喂養(yǎng)的果蠅主要有5種共生菌,本實(shí)驗(yàn)主要針對其中的三種,醋酸菌,乳酸菌和腸桿菌來研究納米二氧化鈦對腸道菌的作用。通過分離出果蠅的三種腸道菌,在體外分別對其用10 nm,50 nm,100 nm二氧化鈦處理,可以明顯的看出高濃度(2 mg/ml)二氧化鈦的殺菌作用,這與所報(bào)道的二氧化鈦具有殺菌作用相吻合。已知的納米二氧化鈦殺菌機(jī)理是,納米二氧化鈦在吸收了一定波長的紫外光波后,其表面產(chǎn)生超氧化離子,超氧化離子作用于菌體致使菌體死亡,也有可能是納米二氧化鈦所具有的小尺寸效應(yīng),使其更容易穿透細(xì)胞膜,進(jìn)入細(xì)胞體內(nèi),破壞細(xì)胞結(jié)構(gòu)甚至遺傳物質(zhì),最終致死菌體死亡。因?yàn)楸緦?shí)驗(yàn)在操作過程中是避光的,這就排除了光催化殺菌的作用,證明了在體外沒有光催化的情況下,納米二氧化鈦也有殺菌作用。接下來,我們把實(shí)驗(yàn)轉(zhuǎn)移到了果蠅體內(nèi),通過給果蠅幼蟲和成蟲喂食納米二氧化鈦,解剖腸道,統(tǒng)計(jì)三種菌的數(shù)量,體內(nèi)實(shí)驗(yàn)得到的結(jié)果與體外實(shí)驗(yàn)明顯不同,體內(nèi)的結(jié)果顯示與對照無明顯差異,菌群數(shù)量沒有受到影響。眾所周知,菌群失衡能造成宿主身體病變,本實(shí)驗(yàn)中喂食納米二氧化鈦后沒發(fā)現(xiàn)果蠅腸道菌受到影響,所以我們就推想果蠅身體狀況應(yīng)該也不會因?yàn)槲故臣{米二氧化鈦而有所改變。之后,我們的實(shí)驗(yàn)進(jìn)一步看了喂食了納米二氧化鈦的幼蟲和成蟲的體重,生長發(fā)育情況,脂代謝及活力,希望通過這些果蠅身體指標(biāo)直觀的看一下納米二氧化鈦對機(jī)體的作用。與推測的一樣,結(jié)果顯示這些指標(biāo)與對照相比并沒有什么不同。本實(shí)驗(yàn)證明體內(nèi)環(huán)境比體外更能保護(hù)腸道菌免受二氧化鈦的毒害。關(guān)于納米二氧化鈦的毒性已經(jīng)在小鼠中得到證實(shí),一定濃度的納米二氧化鈦會造成小鼠肝臟,肺,大腦皮層等組織器官損傷。因?yàn)楸緦?shí)驗(yàn)只采取了兩個(gè)濃度,實(shí)驗(yàn)所用果蠅也只喂食了5天的納米二氧化鈦,雖然沒有對果蠅造成什么不利影響,但是卻不能否認(rèn)納米二氧化鈦的毒性作用,可能是實(shí)驗(yàn)中采用的二氧化鈦濃度太低,使得其毒性沒有發(fā)揮,也可能是因?yàn)樽饔脮r(shí)間太短,對宿主的影響作用還沒有表現(xiàn)出來,所以只能說在低濃度和短時(shí)間內(nèi)納米二氧化鈦不會影響腸道菌數(shù)量和宿主身體健康。至于加大納米二氧化鈦劑量和長期積累效應(yīng)還有待進(jìn)一步研究。
[Abstract]:In recent years, with the rise of the rapid development of nanotechnology makes nano materials have been widely used in people's daily life, the nano titanium dioxide is considered non-toxic to humans, purification, has been applied to air and water, food packaging, cosmetics production and many other aspects. Applications of nano titanium dioxide is wide, making it it's easy with food, air, water enters the human gut, and human gut symbiotic large intestinal flora, these normal symbiotic bacteria play an important role in host metabolism and energy balance, once the disorder may affect host health and cause disease. The photocatalytic bactericidal effect of titanium dioxide has been in practice, nano titanium dioxide once in the body, not in contact with sunlight will produce what kind of effect on the intestinal bacteria, and on the human body caused by the side effects of how to The research of Drosophila as a model organism. The biological experiment, a conserved signaling pathway and mammals, Drosophila and commensal bacteria number, to facilitate the study. Laboratory feeding flies mainly have 5 kinds of symbiotic bacteria, the experiment aimed at three, the acetic acid bacteria, lactic acid bacteria and Enterobacteriaceae to study nano the effect of titanium dioxide on intestinal bacteria. By separating three kinds of intestinal bacteria in Drosophila, in vitro were used on the 10 nm, 50 nm, 100 nm of titanium dioxide, can see the obviously high concentration (2 mg/ml) and the bactericidal effect of titanium dioxide, titanium dioxide has reported the bactericidal effect of nano titanium dioxide dicinfecting coincide. The mechanism is known, nano titanium dioxide absorbs certain wavelengths of ultraviolet light, superoxide ion on the surface, superoxide ions in bacteria resulting in the death of the cell, there may be satisfied The small size effect of titanium dioxide meter, making it easier to penetrate the cell membrane into the cell body, destroy the cellular structure and genetic material, and ultimately lethal bacterial death. Because of this experiment is to avoid light during operation, which precludes the photocatalytic bactericidal effect, proved in vitro without photocatalytic conditions next, nano titanium dioxide also has a bactericidal effect. Then, we put the transfer to the flies, the flies larvae and adults fed nano titanium dioxide, three kinds of intestinal anatomy, counting the number of bacteria, the in vivo experimental results in vitro and in vivo results show significantly different, no significant differences with control, flora the number is not affected. As everyone knows, flora imbalance can cause the host body disease, found no feeding of nano titanium dioxide in this experiment of Drosophila intestinal flora is affected, so we suppose Drosophila health should not be changed because the feeding of nano titanium dioxide. After that, we further see fed nano-TiO2 larvae and adult body weight, growth, lipid metabolism and vitality, hope to watch the effect of nanometer titanium dioxide on the body look through these Drosophila body index intuitive. Like that, the results show that these indexes compared with the control was not different. What this experiment demonstrated that the in vivo environment can protect the intestinal bacteria than in vitro from titanium dioxide poisoning. On the toxicity of nano titanium dioxide has been confirmed in mice, a certain concentration of nano titanium dioxide will cause the liver, lung, brain and other organ damage. Because of this experiment only take the two concentration of the Drosophila feeding only 5 days of nano titanium dioxide, although not on the fly by 浠，

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