本文選題：母乳 + 內(nèi)源性多肽　； 參考：《新鄉(xiāng)醫(yī)學(xué)院》2017年碩士論文

【摘要】：背景抗生素在目前臨床醫(yī)學(xué)中得到了廣泛的應(yīng)用,發(fā)揮了巨大的抗菌功能。但是由于抗生素不科學(xué)的應(yīng)用,繼而產(chǎn)生細(xì)菌耐藥性,這可能制約著抗生素的應(yīng)用與發(fā)展。目前研究發(fā)現(xiàn),抗菌肽(antimicrobial peptides)因其獨特的分子特性和抗菌活性,有望成為抗生素最為理想的替代藥物。PDC213是從新生兒母乳中提取的一種內(nèi)源性抗菌肽,具有較廣泛的抑菌活性,將有良好的臨床價值和應(yīng)用前景。目的研究PDC213對新生兒重癥監(jiān)護(hù)病房(NICU)6種常見致病菌的抑菌活性與抑菌機制。方法(1).利用液相色譜串聯(lián)質(zhì)譜連用技術(shù)發(fā)現(xiàn)PDC213是一種在早產(chǎn)兒母乳中高表達(dá)的內(nèi)源性多肽,通過生物信息學(xué)分析發(fā)現(xiàn)其是一種抑菌功能肽;(2)采用抑菌濃度曲線和抑菌圈實驗分析PDC213的抑菌活性;(3)采用Live/Dead Bac Light TM bacterial viability kit染色結(jié)合熒光顯微鏡觀察分析PDC213的抑菌活性與抑菌機制;(4)采用掃描電鏡、透射電鏡和DNA結(jié)合實驗分析PDC213的抑菌機制。結(jié)果PDC213生物信息學(xué)分析顯示PDC213是一種新型的抑菌肽。PDC213對NICU中常見致病菌金黃色葡萄球菌(S.aureus)和小腸結(jié)腸炎耶爾森氏菌(Y.enterocolitica)具有較強的抑菌活性,在一定時間內(nèi)可有效快速殺死80%以上的S.aureus和Y.enterocolitica。抑菌圈實驗結(jié)果顯示S.aureus和Y.enterocolitica的抑菌圈平均直徑分別為9.93 mm和9.83 mm。熒光顯微鏡顯示S.aureus和Y.enterocolitica的鏡下死亡細(xì)菌數(shù)實驗組較對照組明顯增多。掃描電鏡和透射電鏡實驗顯示經(jīng)過PDC213刺激之后,S.aureus和Y.enterocolitica的表面形態(tài)和內(nèi)部超微結(jié)構(gòu)明顯發(fā)生不規(guī)則改變,出現(xiàn)空泡等現(xiàn)象。DNA結(jié)合實驗顯示不同濃度的PDC213與一定量的核酸DNA結(jié)合后在1%瓊脂糖凝膠上的顯示條帶無差異。結(jié)論PDC213對NICU中常見致病菌S.aureus和Y.enterocolitica具有較強的抑菌活性,PDC213是通過破壞S.aureus和Y.enterocolitica的細(xì)胞膜來殺死細(xì)菌,而不是通過和細(xì)胞內(nèi)核酸結(jié)合來殺死細(xì)菌的。
[Abstract]:Background antibiotics are widely used in clinical medicine and play a great antibacterial function. However, the unscientific application of antibiotics leads to bacterial resistance, which may restrict the application and development of antibiotics. At present, it has been found that antimicrobial peptides. because of its unique molecular characteristics and antibacterial activity, it is expected to be the most ideal alternative to antibiotics. PDC213 is an endogenous antimicrobial peptide extracted from newborn breast milk and has a wide range of bacteriostatic activities. It will have good clinical value and application prospect. Objective to study the antimicrobial activity and mechanism of PDC213 against six common pathogenic bacteria in neonatal intensive care unit (NICU). Methods the method was used. Liquid chromatography-tandem mass spectrometry (LC-MS) showed that PDC213 was a highly expressed endogenous polypeptide in the breast milk of preterm infants. The bacteriostatic activity of PDC213 was analyzed by bioinformatics analysis, which was a kind of bacteriostasis peptide. (2) the bacteriostatic activity of PDC213 was analyzed by bacteriostatic concentration curve and bacteriostasis test. (3) the bacteriostatic activity of PDC213 was analyzed by Live/Dead Bac Light TM bacterial viability kit staining combined with fluorescence microscope. The mechanism of activity and bacteriostasis was characterized by scanning electron microscope (SEM). The bacteriostatic mechanism of PDC213 was analyzed by transmission electron microscope (TEM) and DNA. Results PDC213 bioinformatics analysis showed that PDC213 was a novel antimicrobial peptide. PDC213 had strong antibacterial activity against S.aureus and Y.enterocolitica, the common pathogenic bacteria in NICU. More than 80% of S.aureus and Y. enterocolitica could be killed quickly in a certain time. The results of bacteriostasis test showed that the average diameter of S.aureus and Y.enterocolitica were 9.93 mm and 9.83 mm respectively. Fluorescence microscope showed that the number of dead bacteria in S.aureus and Y.enterocolitica group was significantly higher than that in control group. Scanning electron microscopy and transmission electron microscopy showed that the surface morphology and internal ultrastructure of S.aureus and Y.enterocolitica changed irregularly after PDC213 stimulation. Vacuolation and other phenomena. DNA-binding experiments showed that there was no difference in the display bands between different concentrations of PDC213 and a certain amount of nucleic acid DNA on 1% agarose gel. Conclusion PDC213 has strong antibacterial activity against S.aureus and Y.enterocolitica in NICU. PDC213 kills bacteria by destroying the cell membrane of S.aureus and Y.enterocolitica, rather than killing bacteria by binding to intracellular nucleic acid.
【學(xué)位授予單位】：新鄉(xiāng)醫(yī)學(xué)院
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：R978

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相關(guān)期刊論文 前10條

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本文編號：1914325