Bu çalışma, Çin Ulusal Doğa Bilimleri Vakfı'nın (82230080) Anahtar projesi olan Seçkin Genç Akademisyenler için Ulusal Bilim Fonu (82025024) tarafından desteklenmiştir;Çin Ulusal Anahtar Ar-Ge Programı (2021YFA1300604); Çin Ulusal Doğa Bilimleri Vakfı (81871735, 82272438 ve 82002245); Seçkin Genç Akademisyenler için Guangdong Doğa Bilimleri Fonu (2023B1515020058); Guangdong Eyaleti Doğa Bilimleri Vakfı (2021A1515011639); Çin'deki Shandong Eyaleti Doğa Bilimleri Vakfı'nın Büyük Devlet Temel Araştırma Geliştirme Programı (ZR2020ZD11); Doktora Sonrası Bilim Vakfı (2022M720059); Güney Tıp Üniversitesi, Nanfang Hastanesi'nin Üstün Gençlik Geliştirme Programı (2022J001).

Mikrobiyota Multi-Omikler için Gelişmiş Bakteriyel Hücre Dışı Vezikül İzolasyonu

<ol>
	<li>Costello, E. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+community+variation+in+human+body+habitats+across+space+and+time.">Bacterial community variation in human body habitats across space and time.</a> Science. 326 (5960), 1694-1697 (2009).</li><li>Greenhalgh, K., Meyer, K. M., Aagaard, K. M., Wilmes, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+human+gut+microbiome+in+health:+establishment+and+resilience+of+microbiota+over+a+lifetime.">The human gut microbiome in health: establishment and resilience of microbiota over a lifetime.</a> Environmental Microbiology. 18 (7), 2103-2116 (2016).</li><li>de Vos, W. M., Tilg, H., Van Hul, M., Cani, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gut+microbiome+and+health:+mechanistic+insights.">Gut microbiome and health: mechanistic insights.</a> Gut. 71 (5), 1020-1032 (2022).</li><li>Zhou, P., Yang, D., Sun, D., Zhou, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gut+microbiome:+New+biomarkers+in+early+screening+of+colorectal+cancer.">Gut microbiome: New biomarkers in early screening of colorectal cancer.</a> Journal of Clinical Laboratory Analysis. 36 (5), 24359 (2022).</li><li>Paik, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+gut+bacteria+produce+&#932;(&#919;)17-modulating+bile+acid+metabolites.">Human gut bacteria produce &#932;(&#919;)17-modulating bile acid metabolites.</a> Nature. 603 (7903), 907-912 (2022).</li><li>Parada Venegas, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Short+chain+fatty+acids+(SCFAs)-mediated+gut+epithelial+and+immune+regulation+and+its+relevance+for+inflammatory+bowel+diseases.">Short chain fatty acids (SCFAs)-mediated gut epithelial and immune regulation and its relevance for inflammatory bowel diseases.</a> Frontiers in Immunology. 10, 277 (2019).</li><li>Jiang, C., Li, G., Huang, P., Liu, Z., Zhao, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Gut+microbiota+and+Alzheimer's+disease.">The Gut microbiota and Alzheimer's disease.</a> Journal of Alzheimer's Disease. 58 (1), 1-15 (2017).</li><li>Morais, L. H., Schreiber, H. L. t., Mazmanian, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+gut+microbiota-brain+axis+in+behaviour+and+brain+disorders.">The gut microbiota-brain axis in behaviour and brain disorders.</a> Nature Reviews Microbiology. 19 (4), 241-255 (2021).</li><li>Kim, J. H., Lee, J., Park, J., Gho, Y. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gram-negative+and+Gram-positive+bacterial+extracellular+vesicles.">Gram-negative and Gram-positive bacterial extracellular vesicles.</a> Seminars in Cell and Developmental Biology. 40, 97-104 (2015).</li><li>Toyofuku, M., Nomura, N., Eberl, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Types+and+origins+of+bacterial+membrane+vesicles.">Types and origins of bacterial membrane vesicles.</a> Nature Reviews Microbiology. 17 (1), 13-24 (2019).</li><li>Xie, J., Li, Q., Haesebrouck, F., Van Hoecke, L., Vandenbroucke, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+tremendous+biomedical+potential+of+bacterial+extracellular+vesicles.">The tremendous biomedical potential of bacterial extracellular vesicles.</a> Trends in Biotechnology. 40 (10), 1173-1194 (2022).</li><li>Coumans, F. A. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methodological+guidelines+to+study+extracellular+vesicles.">Methodological guidelines to study extracellular vesicles.</a> Circulation Research. 120 (10), 1632-1648 (2017).</li><li>Northrop-Albrecht, E. J., Taylor, W. R., Huang, B. Q., Kisiel, J. B., Lucien, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+extracellular+vesicle+isolation+methods+from+human+stool+supernatant.">Assessment of extracellular vesicle isolation methods from human stool supernatant.</a> Journal of Extracellular Vesicles. 11 (4), 12208 (2022).</li><li>Park, Y. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microbial+changes+in+stool,+saliva,+serum,+and+urine+before+and+after+anti-TNF-&#945;+therapy+in+patients+with+inflammatory+bowel+diseases.">Microbial changes in stool, saliva, serum, and urine before and after anti-TNF-&#945; therapy in patients with inflammatory bowel diseases.</a> Scientific Reports. 12 (1), 6359 (2022).</li><li>Tulkens, J., De Wever, O., Hendrix, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analyzing+bacterial+extracellular+vesicles+in+human+body+fluids+by+orthogonal+biophysical+separation+and+biochemical+characterization.">Analyzing bacterial extracellular vesicles in human body fluids by orthogonal biophysical separation and biochemical characterization.</a> Nature Protocols. 15 (1), 40-67 (2020).</li><li>Tulkens, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+levels+of+systemic+LPS-positive+bacterial+extracellular+vesicles+in+patients+with+intestinal+barrier+dysfunction.">Increased levels of systemic LPS-positive bacterial extracellular vesicles in patients with intestinal barrier dysfunction.</a> Gut. 69 (1), 191-193 (2020).</li><li>Kang, C. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+vesicles+derived+from+gut+microbiota,+especially+Akkermansia+muciniphila,+protect+the+progression+of+dextran+sulfate+sodium-induced+colitis.">Extracellular vesicles derived from gut microbiota, especially Akkermansia muciniphila, protect the progression of dextran sulfate sodium-induced colitis.</a> PloS one. 8 (10), 76520 (2013).</li><li>Simonsen, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=What+are+we+looking+at?+Extracellular+vesicles,+lipoproteins,+or+both.">What are we looking at? Extracellular vesicles, lipoproteins, or both.</a> Circulation Research. 121 (8), 920-922 (2017).</li><li>Correll, V. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+small+extracellular+vesicle+isolation+from+expressed+prostatic+secretions+in+urine+for+in-depth+proteomic+analysis.">Optimization of small extracellular vesicle isolation from expressed prostatic secretions in urine for in-depth proteomic analysis.</a> Journal of Extracellular Vesicles. 11 (2), 12184 (2022).</li><li>Liang, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gut+bacterial+extracellular+vesicles:+important+players+in+regulating+intestinal+microenvironment.">Gut bacterial extracellular vesicles: important players in regulating intestinal microenvironment.</a> Gut Microbes. 14 (1), 2134689 (2022).</li><li>Alberti, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+vesicles+derived+from+gut+microbiota+in+inflammatory+bowel+disease+and+colorectal+cancer.">Extracellular vesicles derived from gut microbiota in inflammatory bowel disease and colorectal cancer.</a> Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czech Republic. 165 (3), 233-240 (2021).</li><li>D&#237;ez-Sainz, E., Milagro, F. I., Riezu-Boj, J. I., Lorente-Cebri&#225;n, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+gut+microbiota-derived+extracellular+vesicles+on+obesity+and+diabetes+and+their+potential+modulation+through+diet.">Effects of gut microbiota-derived extracellular vesicles on obesity and diabetes and their potential modulation through diet.</a> Journal of Physiology and Biochemistry. 78 (2), 485-499 (2022).</li><li>Lajqi, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gut+microbiota-derived+small+extracellular+vesicles+endorse+memory-like+inflammatory+responses+in+murine+neutrophils.">Gut microbiota-derived small extracellular vesicles endorse memory-like inflammatory responses in murine neutrophils.</a> Biomedicines. 10 (2), 442 (2022).</li><li>Lee, K. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+extracellular+vesicle+of+gut+microbial+Paenalcaligenes+hominis+is+a+risk+factor+for+vagus+nerve-mediated+cognitive+impairment.">The extracellular vesicle of gut microbial Paenalcaligenes hominis is a risk factor for vagus nerve-mediated cognitive impairment.</a> Microbiome. 8 (1), 107 (2020).</li><li>Villard, A., Boursier, J., Andriantsitohaina, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+and+eukaryotic+extracellular+vesicles+and+nonalcoholic+fatty+liver+disease:+new+players+in+the+gut-liver+axis.">Bacterial and eukaryotic extracellular vesicles and nonalcoholic fatty liver disease: new players in the gut-liver axis.</a> American Journal of Physiology-Gastrointestinal and Liver Physiology. 320 (4), G485-G495 (2021).</li><li>Wei, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Outer+membrane+vesicles+enhance+tau+phosphorylation+and+contribute+to+cognitive+impairment.">Outer membrane vesicles enhance tau phosphorylation and contribute to cognitive impairment.</a> Journal of Cellular Physiology. 235 (5), 4843-4855 (2020).</li><li>Bitto, N. J., Kaparakis-Liaskos, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+of+bacterial+membrane+vesicle+production,+purification,+quantification,+and+examination+of+their+immunogenic+functions.">Methods of bacterial membrane vesicle production, purification, quantification, and examination of their immunogenic functions.</a> Methods in Molecular Biology. 2523, 43-61 (2022).</li><li>Stentz, R., Miquel-Clop&#233;s, A., Carding, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production,+isolation,+and+characterization+of+bioengineered+bacterial+extracellular+membrane+vesicles+derived+from+Bacteroides+thetaiotaomicron+and+their+use+in+vaccine+development.">Production, isolation, and characterization of bioengineered bacterial extracellular membrane vesicles derived from Bacteroides thetaiotaomicron and their use in vaccine development.</a> Methods in Molecular Biology. 2414, 171-190 (2022).</li><li>Zhang, Q., Jeppesen, D. K., Higginbotham, J. N., Franklin, J. L., Coffey, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comprehensive+isolation+of+extracellular+vesicles+and+nanoparticles.">Comprehensive isolation of extracellular vesicles and nanoparticles.</a> Nature Protocols. 18 (5), 1462-1487 (2023).</li><li>Iwai, K., Minamisawa, T., Suga, K., Yajima, Y., Shiba, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+human+salivary+extracellular+vesicles+by+iodixanol+density+gradient+ultracentrifugation+and+their+characterizations.">Isolation of human salivary extracellular vesicles by iodixanol density gradient ultracentrifugation and their characterizations.</a> Journal of Extracellular Vesicles. 5, 30829 (2016).</li><li>Vandeputte, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stool+consistency+is+strongly+associated+with+gut+microbiota+richness+and+composition,+enterotypes+and+bacterial+growth+rates.">Stool consistency is strongly associated with gut microbiota richness and composition, enterotypes and bacterial growth rates.</a> Gut. 65 (1), 57-62 (2016).</li><li>Wen, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+extracellular+vesicles:+A+position+paper+by+the+Microbial+Vesicles+Task+Force+of+the+Chinese+Society+of+Extracellular+Vesicles.">Bacterial extracellular vesicles: A position paper by the Microbial Vesicles Task Force of the Chinese Society of Extracellular Vesicles.</a> Interdisciplinary Medicine. 1, 12046 (2023).</li></ol>

Yazarlar çatışan hiçbir çıkar beyan etmemektedir.

Bakteriyel hücre dışı veziküller (BEV'ler), bakteriler tarafından salgılanan, çok sayıda protein, lipit, nükleik asit ve diğer biyoaktif molekülleri taşıyan, bakterilerin fonksiyonel etkilerine aracılık etmeye katkıda bulunan lipid-çift katmanlı nanopartiküllerdir20. Bağırsaktan elde edilen BEV'lerin inflamatuar bağırsak hastalığı, Crohn hastalığı ve kolorektal kanser gibi hastalıkların gelişiminde rol oynadığı ve ayrıca genel metabolizmayı etkilediği ve bozu...

Bağırsak, insan vücudunda en bol bulunan mikrobiyal toplulukları barındıran organ olarak kabul edilmektedir ve bakterilerin %90'ından fazlası kolonizasyon ve çoğalmadarol oynar 1,2. Kapsamlı kanıtlar, bağırsak mikrobiyotasının bağırsak mikroçevresini modüle ettiğini ve aynı zamanda, öncelikle bozulmuş bir bağırsak bariyeri 3,4 yoluyla uzak organlardaki işlev bozukluğu ile etkileşime girdiğini göstermiştir. Artan kanıtlar, bağırsak mikrobiyotasının dengesizliği ile inflamatuar bağırsak hastalığının (IBD) ilerlemesi arasında bir ilişki olduğunu göstermektedir5,6 ve ayrıca bağırsak-beyin ekseni 5,6,7,8 yoluyla bilişsel bozukluklar. Bakteriler tarafından üretilen bakteriyel hücre dışı veziküller (BEV'ler) bu patolojik süreçlerde önemli rol oynar.
BEV'ler, çapları 20 ila 400 nm arasında değişen, bakteri türevlerini kapsülleyen nano ölçekli parçacıklardır. Bakteriler ve konakçı organizmalar arasındaki etkileşimleri kolaylaştırdıkları gösterilmiştir 9,10. Görünmez olmalarına rağmen, bu parçacıklar, tanısal biyobelirteçler, terapötik hedefler ve ilaç dağıtım araçları olarak ileriye dönük geniş uygulamaları nedeniyle araştırmacıların artan ilgisini çekmiştir11. Ağırlıklı olarak bağırsak bakterilerinden elde edilen BEV'leri incelemek için genellikle biyonumune olarak kullanılan insan dışkısı, diğerleri arasında su, bakteri, lipitler, proteinler, sindirilmemiş gıda artıkları ve pul pul dökülmüş epitel hücrelerinin karmaşık bir karışımını içerir. Karmaşık dışkı bileşimi, BEV'lerin izolasyonu ve saflığı için zorluklar yaratır ve böylece BEV'lerin kapsamlı, objektif ve gerçekçi bir analizini engeller. Bu nedenle, kirletici bileşenlerden kaynaklanan paraziti en aza indirmek ve BEV'lerin verimini artırmak için etkili stratejiler, derhal ilgilenilmesi gereken kritik konular olarak ortaya çıkmıştır.
Mevcut izolasyon stratejileri büyük ölçüde ultra yüksek hızlı santrifüjleme (UC), yoğunluk gradyanlı santrifüjleme (DGC) ve boyut dışlama kromatografisi (SEC) gibi tekniklere dayanmaktadır12,13,14,15,16,17. Şu anda DGC, numunenin ilk yükleme konumu tarafından belirlenen "Yukarıdan aşağıya" ve "Aşağıdan yukarıya" olmak üzere iki sedimantasyon-yüzer modu kapsayan, BEV ayırma alanında en yaygın olarak uygulanan yöntemlerden biridir. Bu metodolojiler, hücre dışı vezikülleri (EV'ler) boyut ve yoğunluk eşitsizliklerine dayalı olarak diğer bileşenlerden ayırarak değişken saflık ve geri kazanım oranları sağlar. Önceki araştırmalar, EV'leri kandakilipoprotein 18 ve idrardaki Tamm-Horsfall proteini19 gibi vücut sıvısı örneklerinde çözünür proteinlerden yeterince ayırmak için tek yaklaşımlı stratejilerin yetersiz olduğunu göstermiştir. Ek olarak, ökaryotik hücre dışı veziküllerin (EEV'ler) boyut dağılımı genellikle BEV'lerinkiyle örtüşür ve bu nedenle BEV verimini optimize etmek için daha fazla metodolojik geliştirme gerektirir. Sonuç olarak, BEV'lerin çalışmasını ilerletmek, etkili ayırma ve saflaştırma metodolojilerinin geliştirilmesine bağlıdır. Özellikle, Tulkens ve ark.15, fekal BEV'leri EEV'lerden ayırmak için ortogonal bir biyofiziksel strateji kullandılar, burada Aşağıdan yukarıya DGC modunun santrifüjleme süresi 18 saate kadardı. Buna karşılık, bu çalışma bunu 7 saate düşürdü, gradyan-ultrasantrifüj süresinden büyük ölçüde tasarruf sağladı ve süreci basitleştirdi.
Bu çalışmada, BEV'leri düşükten aşırı yüksek hıza kadar bir dizi diferansiyel santrifüj hızıyla zenginleştirdikten sonra, optimize edilmiş tampon koşulları altında iki DGC modu kullanan fekal BEV'leri izole ettik ve saflaştırdık. Morfolojiye, partikül boyutuna ve konsantrasyona dayalı değerlendirmeler, bu gelişmiş yöntemle övgüye değer bir performans gösterdi. Bu çalışma, gelecekteki araştırmalar için temel oluşturabilir, uygulamalarını daha geniş bir alana genişletebilir ve insan vücudundaki BEV'lerin heterojenliği hakkında fikir verebilir. Ayrıca BEV ayırma ve analiz tekniklerinin standardizasyonuna da katkıda bulunur.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1 % (w/v) glutaraldehyde (prepared from 2.5 % stock solution in deionized water)</td>
			<td>ACMEC</td>
			<td>AP1126</td>
			<td>Morphological observation for BEVs using TEM at Step 8.3.3</td>
		</tr>
		<tr>
			<td>1 % (w/v) methylcellulose (prepared from original powder in deionized water)</td>
			<td>Sigma-Aldrich</td>
			<td>M7027</td>
			<td>Morphological observation for BEVs using TEM at Step 8.3.6</td>
		</tr>
		<tr>
			<td>1.5 % (w/v) uranyl acetate (prepared from original powder in deionized water)</td>
			<td>Polysciences</td>
			<td>21447-25</td>
			<td>Morphological observation for BEVs using TEM at Step 8.3.5</td>
		</tr>
		<tr>
			<td>1000 &#956;L, 200 &#956;L, 10 &#956;L Pipette</td>
			<td>KIRGEN</td>
			<td>KG1313, KG1212, KG1011</td>
			<td>Transfer the solution</td>
		</tr>
		<tr>
			<td>5 % (w/v) bovine serum albumin solution (prepared from the original powder in TBST buffer)</td>
			<td>Fdbio science</td>
			<td>FD0030</td>
			<td>Used in western blotting for blocking at Step 8.5.6</td>
		</tr>
		<tr>
			<td>5 &#215; loading buffer</td>
			<td>Fdbio science</td>
			<td>FD006</td>
			<td>Used in western blotting and Coomassie brilliant blue stain at Step 8.5.1</td>
		</tr>
		<tr>
			<td>75 % (v/v) alcohol</td>
			<td>LIRCON</td>
			<td>LIRCON-500 mL</td>
			<td>Surface disinfection</td>
		</tr>
		<tr>
			<td>96-well plate</td>
			<td>Rar</td>
			<td>A8096</td>
			<td>Measure the absorbance values&#160;</td>
		</tr>
		<tr>
			<td>Anti-Calnexin antibody</td>
			<td>Abcam</td>
			<td>ab92573</td>
			<td>Western blotting (Primary Antibody)</td>
		</tr>
		<tr>
			<td>Anti-CD63 antibody</td>
			<td>Abcam</td>
			<td>ab134045</td>
			<td>Western blotting (Primary Antibody)</td>
		</tr>
		<tr>
			<td>Anti-CD9 antibody</td>
			<td>Abcam</td>
			<td>ab236630</td>
			<td>Western blotting (Primary Antibody)</td>
		</tr>
		<tr>
			<td>Anti-Flagellin antibody</td>
			<td>Sino Biological</td>
			<td>40067-MM06</td>
			<td>Western blotting (Primary Antibody)</td>
		</tr>
		<tr>
			<td>Anti-Integrin beta 1 antibody</td>
			<td>Abcam</td>
			<td>ab30394</td>
			<td>Western blotting (Primary Antibody)</td>
		</tr>
		<tr>
			<td>Anti-LPS antibody</td>
			<td>Thermo Fisher</td>
			<td>MA1-83152</td>
			<td>Western blotting (Primary Antibody)</td>
		</tr>
		<tr>
			<td>Anti-LTA antibody</td>
			<td>Thermo Fisher&#160;</td>
			<td>MA1-7402</td>
			<td>Western blotting (Primary Antibody)</td>
		</tr>
		<tr>
			<td>Anti-OmpA antibody</td>
			<td>CUSABIO</td>
			<td>CSB-PA359226ZA01EOD, https://www.cusabio.com/</td>
			<td>Western blotting (Primary Antibody)</td>
		</tr>
		<tr>
			<td>Anti-Syntenin antibody</td>
			<td>Abcam</td>
			<td>ab133267</td>
			<td>Western blotting (Primary Antibody)</td>
		</tr>
		<tr>
			<td>Anti-TSG101 antibody</td>
			<td>Abcam</td>
			<td>ab125011</td>
			<td>Western blotting (Primary Antibody)</td>
		</tr>
		<tr>
			<td>Autoclave</td>
			<td>ZEALWAY</td>
			<td>GR110DP</td>
			<td>Sterilization for supplies and mediums used in the experiment</td>
		</tr>
		<tr>
			<td>Balance</td>
			<td>Mettler Toledo</td>
			<td>AL104</td>
			<td>Balance the tube sample-loaded with PBS</td>
		</tr>
		<tr>
			<td>Bicinchoninic acid assay&#160;</td>
			<td>Fdbio science</td>
			<td>FD2001</td>
			<td>Measure protein content of BEVs at Step 8.2</td>
		</tr>
		<tr>
			<td>BioRender</td>
			<td>BioRender</td>
			<td>https://app.biorender.com</td>
			<td>Make the schematic workflow of BEVs isolation and purification showed in Figure 1</td>
		</tr>
		<tr>
			<td>Biosafety cabinet</td>
			<td>Haier</td>
			<td>HR1200- II B2</td>
			<td>Peform the procedures about feces sample handling</td>
		</tr>
		<tr>
			<td>Centrifuge 5810 R; Rotor F-34-6-38</td>
			<td>Eppendorf</td>
			<td>5805000092; 5804727002, adapter: 5804774000</td>
			<td>Preprocess for BEVs (Step 3)</td>
		</tr>
		<tr>
			<td>Chemiluminescence Apparatus</td>
			<td>BIO-OI</td>
			<td>OI600SE-MF</td>
			<td>Used in western blotting for signal detection at Step 8.5.12</td>
		</tr>
		<tr>
			<td>Cytation 5</td>
			<td>BioTek</td>
			<td>F01</td>
			<td>Microplate detector for measuring the absorbance (Step 8.1) and fluorescence (Figure 6) values&#160;</td>
		</tr>
		<tr>
			<td>Dil-labled low density lipoprotein</td>
			<td>ACMEC</td>
			<td>AC12038</td>
			<td>Definition of distribution of interfering components&#160;</td>
		</tr>
		<tr>
			<td>Electrophoresis equipment</td>
			<td>Bio-rad</td>
			<td>1658033</td>
			<td>Used in western blotting for protein separation and transfer at Step 8.5.2, 8.5.3, 8.5.5</td>
		</tr>
		<tr>
			<td>Enhanced Chemiluminescence kit HRP&#160;</td>
			<td>Fdbio science</td>
			<td>FD8020</td>
			<td>Used in western blotting for signal detection at Step 8.5.12</td>
		</tr>
		<tr>
			<td>Escherichia coli&#160;</td>
			<td>American Type Culture Collection</td>
			<td>ATCC8739</td>
			<td>Isolate BEVs as a positive control. Protocol: Dissolve 25 g of the LB powder in 1 L deionized water, and autoclave. Transfer the 800 &#956;L of preserved Escherichia coli into the medium. Cultivate at 37 &#176;C in the incubator shaker. Then centrifuge at 3, 000 &#215; g for 20 min at 4 &#176;C, 12, 000 &#215; g for 30 min at 4 &#176;C, filter the supernatant through 0.22 &#956;m membrane, and perform ultra-speed centrifugation at 160, 000 &#215; g for 70 min at 4 &#176;C. Pellet defined as crude BEVs from Escherichia coli was suspended in 1.2 mL PBS (Step 3, 4).&#160;&#160;&#160;&#160;</td>
		</tr>
		<tr>
			<td>Falcon tubes 50 mL</td>
			<td>KIRGEN</td>
			<td>KG2811</td>
			<td>Preprocess for BEVs (Step 3)</td>
		</tr>
		<tr>
			<td>Feto Protein Staining Buffer</td>
			<td>Absci</td>
			<td>ab.001.50</td>
			<td>Coomassie brilliant blue staining at Step 8.5.4</td>
		</tr>
		<tr>
			<td>Filter paper</td>
			<td>Biosharp</td>
			<td>BS-TFP-070B</td>
			<td>Morphological observation for BEVs using TEM at Step 8.3 (Blotting the solution)</td>
		</tr>
		<tr>
			<td>Formvar/Carbon supported copper grids&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>TEM-FCF200CU50</td>
			<td>Morphological observation for BEVs using TEM at Step 8.3</td>
		</tr>
		<tr>
			<td>HEPES powder</td>
			<td>Meilunbio</td>
			<td>MB6078</td>
			<td>Prepare iodixanol buffers with different concentrations for density gradient centrifugation</td>
		</tr>
		<tr>
			<td>HRP AffiniPure Goat Anti-Mouse IgG (H+L)</td>
			<td>Fdbio science</td>
			<td>FDM007</td>
			<td>Western blotting (Secondary Antibody)</td>
		</tr>
		<tr>
			<td>HRP AffiniPure Goat Anti-Rabbit IgG (H+L)</td>
			<td>Fdbio science</td>
			<td>FDR007</td>
			<td>Western blotting (Secondary Antibody)</td>
		</tr>
		<tr>
			<td>Incubator shaker</td>
			<td>Qiangwen</td>
			<td>DHZ-L</td>
			<td>Cultivate Escherichia coli&#160;</td>
		</tr>
		<tr>
			<td>Kimwipes&#8482; Delicate Task Wipes</td>
			<td>Kimtech Science</td>
			<td>34155</td>
			<td>Wipe the inner wall of the ultracentrifuge tube at Step 4.15</td>
		</tr>
		<tr>
			<td>LB broth</td>
			<td>Hopebio</td>
			<td>HB0128</td>
			<td>Cultivate Escherichia coli&#160;</td>
		</tr>
		<tr>
			<td>Low temperature freezer (-80 &#176;C)</td>
			<td>Haier</td>
			<td>DW-86L338J</td>
			<td>Store the samples</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Alalddin</td>
			<td>M116118</td>
			<td>Used in western blotting for activating PVDF membrane at Step 8.5.5</td>
		</tr>
		<tr>
			<td>Micro tubes 1.5 mL</td>
			<td>KIRGEN</td>
			<td>KG2211</td>
			<td>Recover fractions after density gradient centrifugation</td>
		</tr>
		<tr>
			<td>Micro tubes 2 mL</td>
			<td>KIRGEN</td>
			<td>KG2911</td>
			<td>Recover fractions after density gradient centrifugation</td>
		</tr>
		<tr>
			<td>Micro tubes 5 mL</td>
			<td>BBI</td>
			<td>F610888-0001</td>
			<td>Recover fractions after density gradient centrifugation</td>
		</tr>
		<tr>
			<td>Microplate reader&#160;</td>
			<td>Thermo Fisher&#160;</td>
			<td>Multiskan MK3</td>
			<td>Measure protein content of BEVs at Step 8.2</td>
		</tr>
		<tr>
			<td>Millipore filter 0.22 &#956;m</td>
			<td>Merck millipore</td>
			<td>SLGP033RB</td>
			<td>Filtration sterilization; Material: polyethersulfone, PES</td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>GHTECH</td>
			<td>1.01307.040</td>
			<td>Density gradient centrifugation solution</td>
		</tr>
		<tr>
			<td>NaOH</td>
			<td>GHTECH</td>
			<td>1.01394.068</td>
			<td>Density gradient centrifugation solution (pH adjustment)</td>
		</tr>
		<tr>
			<td>Optima&#8482; XPN-100</td>
			<td>Beckman Coulter</td>
			<td>A94469</td>
			<td>Ultracentrifugation for BEVs isolation at Step 4, 7</td>
		</tr>
		<tr>
			<td>OptiPrep&#8482;</td>
			<td>Serumwerk Bernburg AG</td>
			<td>1893</td>
			<td>Density gradient centrifugation stock solution</td>
		</tr>
		<tr>
			<td>Orbital Shaker</td>
			<td>Youning</td>
			<td>CS-100</td>
			<td>Dissolve feces at Step 2</td>
		</tr>
		<tr>
			<td>Phosphate buffered saline</td>
			<td>Procell</td>
			<td>PB180327</td>
			<td>Dissolve feces at Step 2</td>
		</tr>
		<tr>
			<td>Pipettor</td>
			<td>Eppendorf</td>
			<td>3120000267, 3120000259</td>
			<td>Transfer the solution</td>
		</tr>
		<tr>
			<td>Plastic pasteur pipette</td>
			<td>ABCbio</td>
			<td>ABC217003-4</td>
			<td>Remove supernatant in preprocessing at Step 3.4</td>
		</tr>
		<tr>
			<td>Polyvinylidene difluoride (PVDF) membranes</td>
			<td>Millipore</td>
			<td>ISEQ00010, IPVH00010</td>
			<td>Used in western blotting for protein transfer at Step 8.5.5</td>
		</tr>
		<tr>
			<td>Prefabricated polyacrylamide gel, 4&#8211;20% 15 Wells</td>
			<td>ACE</td>
			<td>F15420Gel</td>
			<td>Used in western blotting for protein separation at Step 8.5.2, 8.5.3</td>
		</tr>
		<tr>
			<td>Primary antibody diluent</td>
			<td>Fdbio science</td>
			<td>FD0040</td>
			<td>Used in western blotting at Step 8.5.8</td>
		</tr>
		<tr>
			<td>Protein ladder</td>
			<td>Fdbio science</td>
			<td>FD0672</td>
			<td>Used in western blotting and Coomassie brilliant blue stain at Step 8.5</td>
		</tr>
		<tr>
			<td>Rapid protein blotting solution</td>
			<td>UBIO</td>
			<td>UW0500</td>
			<td>Used in western blotting for protein transfer at Step 8.5.5</td>
		</tr>
		<tr>
			<td>Rotor SW 32 Ti Swinging-Bucket Rotor</td>
			<td>Beckman Coulter</td>
			<td>369650</td>
			<td>Ultracentrifugation for BEVs isolation at Step 4, 7</td>
		</tr>
		<tr>
			<td>Syringe 20 mL, 50 mL&#160;</td>
			<td>Jetway</td>
			<td>ZSQ-20ML, YCXWJZSQ-50 mL</td>
			<td>Transfer buffers amd remove supernatant in preprocessing</td>
		</tr>
		<tr>
			<td>TBS powder</td>
			<td>Fdbio science</td>
			<td>FD1021</td>
			<td>Used in western blotting at Step 8.5</td>
		</tr>
		<tr>
			<td>Transmission electron microscope (TEM)</td>
			<td>Hitachi&#160;</td>
			<td>H-7650</td>
			<td>Morphological observation for BEVs at Step 8.3</td>
		</tr>
		<tr>
			<td>Tween-20</td>
			<td>Fdbio science</td>
			<td>FD0020</td>
			<td>Used in western blotting at Step 8.5</td>
		</tr>
		<tr>
			<td>Ultracentrifuge tube</td>
			<td>Beckman</td>
			<td>326823, 355642</td>
			<td>Ultracentrifugation for BEVs isolation at Step 4, 7</td>
		</tr>
		<tr>
			<td>Ultra-clean bench</td>
			<td>AIRTECH</td>
			<td>SW-CJ-2FD</td>
			<td>Peform the procedures about liquid handling</td>
		</tr>
		<tr>
			<td>Water bath</td>
			<td>Bluepard</td>
			<td>CU600</td>
			<td>Used for measuring protein content of BEVs at Step 8.2.5</td>
		</tr>
		<tr>
			<td>ZetaView</td>
			<td>Particle Metrix</td>
			<td>S/N 21-734, Software ZetaView (version 8.05.14 SP7)</td>
			<td>Nanoparticle tracking analysis (NTA) for measuring the particle size and concentrarion of BEVs at Step 8.4</td>
		</tr>
	</tbody>
</table>

isolation and purification of bacterial extracellular vesicles from human feces using density gradient centrifugation

Bakteriyel hücre dışı veziküller (BEV'ler), ana bakterilerden miras alınan proteinler, lipitler ve nükleik asitler gibi biyoaktif molekülleri aktaran, bakteri-bakteri ve bakteri-konakçı iletişiminde aktif rol oynayan bakterilerden türetilen nanoveziküllerdir. Bağırsak mikrobiyotasından türetilen BEV'lerin gastrointestinal sistem içinde etkileri vardır ve uzak organlara ulaşabilir, bu da fizyoloji ve patoloji için önemli etkilere neden olur. İnsan dışkısından elde edilen BEV'lerin türlerini, miktarlarını ve rollerini araştıran teorik araştırmalar, bağırsak mikrobiyotasından BEV'lerin salgılanmasını ve işlevini anlamak için çok önemlidir. Bu araştırmalar aynı zamanda BEV'leri izole etmek ve saflaştırmak için mevcut stratejide bir iyileştirme gerektirmektedir.
Bu çalışma, iki yoğunluk gradyanlı santrifüj (DGC) modu oluşturarak BEV'lerin izolasyon ve saflaştırma sürecini optimize etti: Yukarıdan aşağıya ve Aşağıdan yukarıya. BEV'lerin zenginleştirilmiş dağılımı 6 ila 8 (F6-F8) fraksiyonlarında belirlendi. Yaklaşımın etkinliği, partikül morfolojisi, boyutu, konsantrasyonu ve protein içeriğine göre değerlendirildi. Partikül ve protein geri kazanım oranları hesaplandı ve iki DGC modunun geri kazanımını ve saflığını karşılaştırmak için spesifik belirteçlerin varlığı analiz edildi. Sonuçlar, Yukarıdan aşağıya santrifüj modunun daha düşük kontaminasyon seviyelerine sahip olduğunu ve Aşağıdan yukarıya modelinkine benzer bir geri kazanım oranı ve saflığa ulaştığını gösterdi. 108 / mg'lık bir fekal BEV konsantrasyonu elde etmek için 7 saatlik bir santrifüj süresi yeterliydi.
Bu yöntem, dışkı dışında, bileşenlerdeki ve viskozitedeki farklılıklara göre uygun modifikasyonla diğer vücut sıvısı tiplerine de uygulanabilir. Sonuç olarak, bu ayrıntılı ve güvenilir protokol, BEV'lerin standartlaştırılmış izolasyonunu ve saflaştırılmasını kolaylaştıracak ve böylece sonraki multi-omik analiz ve fonksiyonel deneyler için bir temel oluşturacaktır.

The gut is widely recognized as the organ harboring the most abundant microbial communities in the human body, with over 90% of bacteria involved in colonization and multiplication1,2. Extensive evidence has demonstrated that the gut microbiota modulates the gut microenvironment and simultaneously interacts with dysfunction in distant organs, primarily through an impaired intestinal barrier3,4. Mounting evidence indicates a correlation between the imbalance of gut microbiota and the progression of inflammatory bowel disease (IBD)5,6, as well as cognitive disorders through the gut-brain axis5,6,7,8. Bacterial extracellular vesicles (BEVs) produced by bacteria play significant roles in these pathological processes.
BEVs are nanoscale particles encapsulating bacterial derivatives, with diameters ranging from 20 to 400 nm. They have been demonstrated to facilitate interactions between bacteria and their host organisms9,10. Despite their invisibility, these particles have garnered increasing attention from researchers due to their prospective broad applications as diagnostic biomarkers, therapeutic targets, and drug delivery vehicles11. Human feces, often used as biospecimens for studying BEVs, predominantly sourced from gut bacteria, contain a complex mixture of water, bacteria, lipids, proteins, undigested food residue, and exfoliated epithelial cells among others. The intricate fecal composition poses challenges to the isolation and purity of BEVs, thereby impeding a comprehensive, objective, and realistic analysis of BEVs. Hence, effective strategies to minimize interference from contaminating components and enhance the yield of BEVs have emerged as critical issues warranting immediate attention.
Existing isolation strategies largely rely on techniques such as ultra-high-speed centrifugation (UC), density gradient centrifugation (DGC), and size exclusion chromatography (SEC)12,13,14,15,16,17. Currently, DGC is one of the most widely applied methods in the field of BEV separation, encompassing two sedimentation-floating modes, &#34;Top-down&#34; and &#34;Bottom-up&#34;, which are determined by the initial loading position of the sample. These methodologies differentiate extracellular vesicles (EVs) from other components based on size and density disparities, yielding variable purity and recovery rates. Prior research has indicated that single-approach strategies are insufficient for adequately separating EVs from soluble proteins in body fluid samples, such as lipoprotein in blood18 and Tamm-Horsfall protein in urine19. Additionally, the size distribution of eukaryotic extracellular vesicles (EEVs) often overlaps with that of BEVs, thereby necessitating further methodological enhancements to optimize BEV yield. Consequently, advancing the study of BEVs hinges on the development of effective separation and purification methodologies. Notably, Tulkens et al15 employed an orthogonal biophysical strategy to separate fecal BEVs from EEVs, in which the centrifugation time of a Bottom-up DGC mode was up to 18 h. In contrast, this study reduced it to 7 h, greatly saving the gradient-ultracentrifugation time and simplifying the process.
In the present study, we isolated and purified fecal BEVs employing two DGC modes under optimized buffer conditions, after enriching BEVs with a range of differential centrifugation speeds, from low to extremely high velocity. Evaluations based on morphology, particle size, and concentration indicated a commendable performance by this enhanced method. This study could serve as the foundation for future research, extending its applications to a broader domain, and offering insights into the heterogeneity of BEVs within the human body. It also contributes to the standardization of BEV separation and analysis techniques.

Yazar Spotlight: Bakteriyel Hücre Dışı Veziküllerin Ayrılması ve Heterojenliği Üzerine Araştırmaların Hızlandırılması 

Yoğunluk Gradyanlı Santrifüj Kullanılarak İnsan Dışkısından Bakteriyel Hücre Dışı Veziküllerin İzolasyonu ve Saflaştırılması

Our study isolates, purifies, and characterize bacterial extracellular vesicles from physicists using density gradient centrifugation. We aim to address the separation of BEVs from contaminants and provide a reliable method for researchers. Our protocol reduces centrifugation time from 18 to 7 hours.Top down mode improves BEV separation and reduces contamination from liver proteins. Our method simplifies the separation of BEVs, setting a standard for future studies. It can be applied to other body fluids with appropriate modification, enhancing our understanding and facilitating the study of BEVs revealing their inherent heterogeneity within the human body.

BEV ile zenginleştirilmiş fraksiyonların dağılımını belirleyin Bakteriyel hücre dışı veziküllerin (BEV'ler) zenginleştirilmiş fraksiyonlarının dağılımını belirlemek için, OD 340 nm'deki absorbans değerlerini ölçmek için boş bir kontrol kuruldu ve her fraksiyonun yoğunluğu ölçümlere ve iyodiksanol yönergelerine göre hesaplandı (Adım 8.1). Tablo 2 , F4 ila F9 fraksiyonlarının, tipik olarak hücre dışı veziküllerle ilişkili aralıkta yoğunlukl...

Watch this Scientific Journal Video about Accelerating Research on Bacterial Extracellular Vesicles Separation and Heterogeneity at JoVE.com

Bu çalışma, yoğunluk gradyanlı santrifüjleme (DGC) yoluyla insan dışkısından zenginleştirilmiş bakteriyel hücre dışı vezikülleri (BEV'ler) izole etmek ve saflaştırmak için bir yöntemi açıklamakta, BEV'lerin fiziksel özelliklerini morfoloji, partikül boyutu ve konsantrasyondan tanımlamakta ve DGC yaklaşımının klinik ve bilimsel araştırmalardaki potansiyel uygulamalarını tartışmaktadır.

Bacterial extracellular vesicles (BEVs) are nanovesicles derived from bacteria that play an active role in bacteria-bacteria and bacteria-host ...

Çalışmamız, yoğunluk gradyanlı santrifüjleme kullanarak fizikçilerden bakteri hücre dışı vezikülleri izole eder, saflaştırır ve karakterize eder. BEV'lerin kirleticilerden ayrılmasını ele almayı ve araştırmacılar için güvenilir bir yöntem sağlamayı amaçlıyoruz. Protokolümüz santrifüj süresini 18 saatten 7 saate düşürür.Yukarıdan aşağıya mod, BEV ayrımını iyileştirir ve karaciğer proteinlerinden kontaminasyonu azaltır. Yöntemimiz, BEV'lerin ayrılmasını basitleştirerek gelecekteki çalışmalar için bir standart belirler. Uygun modifikasyonla diğer vücut sıvılarına uygulanabilir, anlayışımızı geliştirir ve insan vücudundaki doğal heterojenliklerini ortaya çıkaran BEV'lerin incelenmesini kolaylaştırır.

isolation-purification-bacterial-extracellular-vesicles-from-human

Research

JoVE Journal

Biology

Isolation and Purification of Bacterial Extracellular Vesicles from Human Feces Using Density Gradient Centrifugation

1.7K Görüntüleme.  Southern Medical University. Çalışmamız, yoğunluk gradyanlı santrifüjleme kullanarak fizikçilerden bakteri hücre dışı vezikülleri izole eder, saflaştırır ve karakterize eder. BEV'lerin kirleticilerden ayrılmasını ele almayı ve araştırmacılar için güvenilir bir yöntem sağlamayı amaçlıyoruz. Protokolümüz santrifüj süresini 18 saatten 7 saate düşürür.Yukarıdan aşağıya mod, BEV ayrımını iyileştirir ve karaciğer proteinlerinden kontaminasyonu azaltır. Yöntemimiz, BEV'ler...

Video: Yazar Spotlight: Bakteriyel Hücre Dışı Veziküllerin Ayrılması ve Heterojenliği Üzerine Araştırmaların Hızlandırılması 

Bacterial extracellular vesicles (BEVs) are nanovesicles derived from bacteria that play an active role in bacteria-bacteria and bacteria-host communication, transferring bioactive molecules such as proteins, lipids, and nucleic acids inherited from the parent bacteria. BEVs derived from the gut microbiota have effects within the gastrointestinal tract and can reach distant organs, resulting in significant implications for physiology and pathology. Theoretical investigations that explore the types, quantities, and roles of BEVs derived from human feces are crucial for understanding the secretion and function of BEVs from the gut microbiota. These investigations also necessitate an improvement in the current strategy for isolating and purifying BEVs.
This study optimized the isolation and purification process of BEVs by establishing two density gradient centrifugation (DGC) modes: Top-down and Bottom-up. The enriched distribution of BEVs was determined in fractions 6 to 8 (F6-F8). The effectiveness of the approach was evaluated based on particle morphology, size, concentration, and protein content. The particle and protein recovery rates were calculated, and the presence of specific markers was analyzed to compare the recovery and purity of the two DGC modes. The results indicated that the Top-down centrifugation mode had lower contamination levels and achieved a recovery rate and purity similar to that of the Bottom-up mode. A centrifugation time of 7 h was sufficient to achieve a fecal BEV concentration of 108/mg.
Apart from feces, this method could be applied to other body fluid types with proper modification according to the differences in components and viscosity. In conclusion, this detailed and reliable protocol would facilitate the standardized isolation and purification of BEVs and thus, lay a foundation for subsequent multi-omics analysis and functional experiments.

This study describes a method to isolate and purify bacterial extracellular vesicles (BEVs) enriched from human feces via density gradient centrifugation (DGC), identifies the physical characteristics of BEVs from morphology, particle size, and concentration, and discusses the potential applications of the DGC approach in clinical and scientific research.

Biyoloji

Bacterial Extracellular Vesicles (BEVs) Enrichment from Human Faeces Using Differential Centrifugation Speeds

To begin, take the prepared human fecal samples. Cool the high speed refrigerated centrifuge to 4 degrees Celsius. Use PBS to adjust the weight of the sample tubes to 0.1 grams, and centrifuge them at 3, 000 G for 20 minutes at 4 degrees Celsius.Using a plastic pipette, transfer the supernatant into two 50 milliliter tubes, leaving 1 milliliter behind. Then, centrifuge the supernatant at 12, 000 G for 30 minutes at 4 degrees Celsius. Using a 20 milliliter syringe, aspirate the supernatant, and remove the needle from the syringe.Filter the liquid through 0.22 micrometer filters into 50 milliliter tubes. Next, wipe the bucket with 75%alcohol to eliminate any remaining contamination. Transfer approximately 30 milliliters of the filtered fecal supernatant into the ultracentrifuge tube.Fill the tube with approximately 8 milliliters of PBS, leaving a 3 millimeter gap from the tube's opening. Place the two ultracentrifuge tubes in opposing ultracentrifugation buckets, and equalize the weight of the two buckets using PBS. Load all buckets onto the rotor, irrespective of whether they are loaded with tubes.Place the samples in the centrifuge, initiate the vacuum and spin them at 160, 000 G for 70 minutes at 4 degrees Celsius. As soon as the centrifugation completes, release the chamber vacuum and open the door of the ultra centrifuge. Then, promptly remove the rotor.Transfer the buckets from the rotor to the rack, and pick up the tubes using a nipper. Discard the supernatant, and save the visible brown pellets. Add 1 milliliter of pre-chilled PBS to resuspend the pellets completely.Fill the tube with approximately 37 milliliters of PBS, leaving a 3 millimeter gap from the opening. After performing another round of ultracentrifugation, discard the supernatant and leave the tube inverted for 5 minutes. Remove any remaining solution on the inner wall with wipers.Using a 1, 000 microliter pipette, add 1.2 milliliters of pre-chilled PBS to resuspend pellets, and mix them by pipetting. Transfer 1.2 milliliters of the PBS BEV solution from one ultracentrifuge tube to a clean 1.5 milliliter micro tube.

Diferansiyel Santrifüj Hızları Kullanılarak İnsan Dışkısından Bakteriyel Hücre Dışı Veziküllerin (BEV'ler) Zenginleştirilmesi

Establishment of a Density Gradient Centrifugation System to Isolate and Purify Bacterial Extracellular Vesicles (BEVs) from Human Faeces

To begin, take 500 microliters of the prepared PBS/BEV solution. Combine it with three milliliters of PBS and mix gently using a 1, 000 microliter pipette. Place a 31 milliliter ultracentrifuge tube on a foam plate with holes, and label the tube with a downward arrow.Then hold a 1, 000 microliter pipette vertically and add three milliliters of the 50%iodixanol solution to the bottom of the tube. Place a tube holder slightly above the level of the foam plate below the tube opening, and tilt the tube to an angle of 70 degrees. Using a 1, 000 microliter pipette, add three milliliters of 40%iodixanol solution on top of the 50%iodixanol solution.Then layer three milliliters of 20%iodixanol solution on the 40%iodixanol solution. Using a 1, 000 microliter pipette, add three milliliters of a 10%iodixanol solution on top of the prepared 20%iodixanol solution. Next, add 3.5 milliliters of the PBS/BEV solution on top of the 10%iodixanol solution, and gently return the tubes to an upright position.Now, position a 31 milliliter ultracentrifuge tube on a foam plate with holes, and label it with an upward arrow. Using a 1, 000 microliter pipette, vertically add 2.5 milliliters of the 60%iodixanol stock solution into the bottom of the tube, and combine it with 500 microliters of PBS/BEV solution to get three milliliters of 50%iodixanol BEV solution. Mix the solution thoroughly by pipetting.Then after layering 40, 20 and 10%iodixanol solution in sequence, use a 1, 000 microliter pipette to add 3.5 milliliters of PBS on top of the 10%iodixanol solution. Adjust the weight of the two tubes with PBS to a total weight within plus minus 0.005 grams. Next, position the tubes in the buckets and centrifuge them at 160, 000 G for seven hours at four degrees Celsius.Using a pipetter, collect the fractions obtained from a gradient ultracentrifugation mode sequentially from top to bottom against the sidewall into 10 separate 38.5 milliliter ultracentrifuge tubes. Then ultracentrifuge the fractions at 160, 000 G for 70 minutes at four degrees Celsius. Remove the supernatant, and invert the ultracentrifuge tubes for five minutes.Next, resuspend the pellets in 200 microliters of pre-chilled PBS using a 200 microliter pipette. Transfer the PBS/BEV solution into a clean 1.5 milliliter microtube. Label the fractions from F1 to F10 as obtained from one gradient ultracentrifugation mode, and proceed for analysis.