We would like to thank Helty Adisetiyo, PhD and Shangxin Yang, PhD for the development of the protocol.Overall support for the International Maternal Pediatric Adolescent AIDS Clinical Trials Group (IMPAACT) was provided by the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH) under Award Numbers UM1AI068632 (IMPAACT LOC), UM1AI068616 (IMPAACT SDMC) and UM1AI106716 (IMPAACT LC), with co-funding from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) and the National Institute of Mental Health (NIMH). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

For all protocol steps, proper personal protective equipment (PPE) must be worn, and stringent contamination prevention approaches need to be taken. Observe flow of work from pre-amplification work areas to post-amplification work areas to minimize contamination of samples. All supplies used are sterile, free of RNase, DNase, DNA, and pyrogen. All pipette tips are filtered. A flowchart of the protocol steps is provided (Figure 1).
1. Sample Lysis
<p class="jove_...

<ol>
	<li>Ahern, P. P., Faith, J. J., Gordon, J. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mining+the+human+gut+microbiota+for+effector+strains+that+shape+the+immune+system.">Mining the human gut microbiota for effector strains that shape the immune system.</a> Immunity. 40 (6), 815-823 (2014).</li><li>Postler, T. S., Ghosh, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Understanding+the+Holobiont:+How+Microbial+Metabolites+Affect+Human+Health+and+Shape+the+Immune+System.">Understanding the Holobiont: How Microbial Metabolites Affect Human Health and Shape the Immune System.</a> Cell Metab. , (2017).</li><li>Hall, M. 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=Inter-personal+diversity+and+temporal+dynamics+of+dental,+tongue,+and+salivary+microbiota+in+the+healthy+oral+cavity.">Inter-personal diversity and temporal dynamics of dental, tongue, and salivary microbiota in the healthy oral cavity.</a> NPJ Biofilms Microbiomes. 3, 2 (2017).</li><li>Perez Perez, G. I., 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=Body+Site+Is+a+More+Determinant+Factor+than+Human+Population+Diversity+in+the+Healthy+Skin+Microbiome.">Body Site Is a More Determinant Factor than Human Population Diversity in the Healthy Skin Microbiome.</a> PLoS One. 11 (4), e0151990 (2016).</li><li>Hamady, M., Knight, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microbial+community+profiling+for+human+microbiome+projects:+Tools,+techniques,+and+challenges.">Microbial community profiling for human microbiome projects: Tools, techniques, and challenges.</a> Genome Res. 19 (7), 1141-1152 (2009).</li><li>Human Microbiome Project, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+framework+for+human+microbiome+research.">A framework for human microbiome research.</a> Nature. 486 (7402), 215-221 (2012).</li><li>Kim, 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=Optimizing+methods+and+dodging+pitfalls+in+microbiome+research.">Optimizing methods and dodging pitfalls in microbiome research.</a> Microbiome. 5 (1), 52 (2017).</li><li>Hugerth, L. W., Andersson, A. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysing+Microbial+Community+Composition+through+Amplicon+Sequencing:+From+Sampling+to+Hypothesis+Testing.">Analysing Microbial Community Composition through Amplicon Sequencing: From Sampling to Hypothesis Testing.</a> Front Microbiol. 8, 1561 (2017).</li><li>Caporaso, J. 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=Ultra-high-throughput+microbial+community+analysis+on+the+Illumina+HiSeq+and+MiSeq+platforms.">Ultra-high-throughput microbial community analysis on the Illumina HiSeq and MiSeq platforms.</a> ISME J. 6 (8), 1621-1624 (2012).</li><li>Pannaraj, P. 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=Association+Between+Breast+Milk+Bacterial+Communities+and+Establishment+and+Development+of+the+Infant+Gut+Microbiome.">Association Between Breast Milk Bacterial Communities and Establishment and Development of the Infant Gut Microbiome.</a> JAMA Pediatr. , (2017).</li><li>Ho, F. C., Wong, R. L., Lawton, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+colostral+and+breast+milk+cells.+A+light+and+electron+microscopic+study.">Human colostral and breast milk cells. A light and electron microscopic study.</a> Acta Paediatr Scand. 68 (3), 389-396 (1979).</li><li>Parmely, M. J., Beer, A. E., Billingham, 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=In+vitro+studies+on+the+T-lymphocyte+population+of+human+milk.">In vitro studies on the T-lymphocyte population of human milk.</a> J Exp Med. 144 (2), 358-370 (1976).</li><li>Sabbaj, 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=Human+immunodeficiency+virus-specific+CD8(+)+T+cells+in+human+breast+milk.">Human immunodeficiency virus-specific CD8(+) T cells in human breast milk.</a> J Virol. 76 (15), 7365-7373 (2002).</li><li>Jimenez, 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=Metagenomic+Analysis+of+Milk+of+Healthy+and+Mastitis-Suffering+Women.">Metagenomic Analysis of Milk of Healthy and Mastitis-Suffering Women.</a> J Hum Lact. 31 (3), 406-415 (2015).</li><li>Ghosh, M. 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=Quantitation+of+human+immunodeficiency+virus+type+1+in+breast+milk.">Quantitation of human immunodeficiency virus type 1 in breast milk.</a> J Clin Microbiol. 41 (6), 2465-2470 (2003).</li><li>Lim, N. Y., Roco, C. A., Frostegard, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transparent+DNA/RNA+Co-extraction+Workflow+Protocol+Suitable+for+Inhibitor-Rich+Environmental+Samples+That+Focuses+on+Complete+DNA+Removal+for+Transcriptomic+Analyses.">Transparent DNA/RNA Co-extraction Workflow Protocol Suitable for Inhibitor-Rich Environmental Samples That Focuses on Complete DNA Removal for Transcriptomic Analyses.</a> Front Microbiol. 7, 1588 (2016).</li><li>Bender, J. 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=Maternal+HIV+infection+influences+the+microbiome+of+HIV-uninfected+infants.">Maternal HIV infection influences the microbiome of HIV-uninfected infants.</a> Sci Transl Med. 8 (349), 349ra100 (2016).</li><li>Cox, M. J., Cookson, W. O., Moffatt, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sequencing+the+human+microbiome+in+health+and+disease.">Sequencing the human microbiome in health and disease.</a> Hum Mol Genet. 22 (R1), R88-R94 (2013).</li><li>Lauder, A. P., 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=Comparison+of+placenta+samples+with+contamination+controls+does+not+provide+evidence+for+a+distinct+placenta+microbiota.">Comparison of placenta samples with contamination controls does not provide evidence for a distinct placenta microbiota.</a> Microbiome. 4 (1), 29 (2016).</li><li>Salter, S. 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=Reagent+and+laboratory+contamination+can+critically+impact+sequence-based+microbiome+analyses.">Reagent and laboratory contamination can critically impact sequence-based microbiome analyses.</a> BMC Biol. 12, 87 (2014).</li><li>Walker, 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=16S+rRNA+gene-based+profiling+of+the+human+infant+gut+microbiota+is+strongly+influenced+by+sample+processing+and+PCR+primer+choice.">16S rRNA gene-based profiling of the human infant gut microbiota is strongly influenced by sample processing and PCR primer choice.</a> Microbiome. 3, 26 (2015).</li><li>Glassing, A., Dowd, S. E., Galandiuk, S., Davis, B., Chiodini, 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=Inherent+bacterial+DNA+contamination+of+extraction+and+sequencing+reagents+may+affect+interpretation+of+microbiota+in+low+bacterial+biomass+samples.">Inherent bacterial DNA contamination of extraction and sequencing reagents may affect interpretation of microbiota in low bacterial biomass samples.</a> Gut Pathog. 8, 24 (2016).</li><li>Kennedy, K., Hall, M. W., Lynch, M. D., Moreno-Hagelsieb, G., Neufeld, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluating+bias+of+illumina-based+bacterial+16S+rRNA+gene+profiles.">Evaluating bias of illumina-based bacterial 16S rRNA gene profiles.</a> Appl Environ Microbiol. 80 (18), 5717-5722 (2014).</li><li>Weiss, 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=Tracking+down+the+sources+of+experimental+contamination+in+microbiome+studies.">Tracking down the sources of experimental contamination in microbiome studies.</a> Genome Biol. 15 (12), 564 (2014).</li><li>Aho, V. 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=The+microbiome+of+the+human+lower+airways:+a+next+generation+sequencing+perspective.">The microbiome of the human lower airways: a next generation sequencing perspective.</a> World Allergy Organ J. 8 (1), 23 (2015).</li><li>Charlson, E. 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=Topographical+continuity+of+bacterial+populations+in+the+healthy+human+respiratory+tract.">Topographical continuity of bacterial populations in the healthy human respiratory tract.</a> Am J Respir Crit Care Med. 184 (8), 957-963 (2011).</li><li>Bittinger, 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=Improved+characterization+of+medically+relevant+fungi+in+the+human+respiratory+tract+using+next-generation+sequencing.">Improved characterization of medically relevant fungi in the human respiratory tract using next-generation sequencing.</a> Genome Biol. 15 (10), 487 (2014).</li><li>Jervis-Bardy, 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=Deriving+accurate+microbiota+profiles+from+human+samples+with+low+bacterial+content+through+post-sequencing+processing+of+Illumina+MiSeq+data.">Deriving accurate microbiota profiles from human samples with low bacterial content through post-sequencing processing of Illumina MiSeq data.</a> Microbiome. 3, 19 (2015).</li><li>Knights, 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=Bayesian+community-wide+culture-independent+microbial+source+tracking.">Bayesian community-wide culture-independent microbial source tracking.</a> Nat Methods. 8 (9), 761-763 (2011).</li><li>Lazarevic, V., Gaia, N., Girard, M., Schrenzel, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decontamination+of+16S+rRNA+gene+amplicon+sequence+datasets+based+on+bacterial+load+assessment+by+qPCR.">Decontamination of 16S rRNA gene amplicon sequence datasets based on bacterial load assessment by qPCR.</a> BMC Microbiol. 16, 73 (2016).</li><li>Kurilshikov, A., Wijmenga, C., Fu, J., Zhernakova, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Host+Genetics+and+Gut+Microbiome:+Challenges+and+Perspectives.">Host Genetics and Gut Microbiome: Challenges and Perspectives.</a> Trends Immunol. 38 (9), 633-647 (2017).</li><li>. Mock microbial communities Available from: <a target="_blank" href="https://www.atcc.org/en/Products/Microbiome_Standards.aspx?utm_id=t170601524l1">https://www.atcc.org/en/Products/Microbiome_Standards.aspx?utm_id=t170601524l1</a> (2017)</li></ol>

Targeted next-generation sequencing of 16S rRNA is a widely used, rapid technique for microbiome characterization18. However, many factors, including batch effects, environmental contamination, sample cross-contamination, sensitivity, and reproducibility can adversely affect experimental results and confound their interpretation7,19,20. To best facilitate robust 16S analyses, microbiome workflows must inc...

The microbial communities that colonize humans are believed to be critically important to human health and disease influencing metabolism, immune development, susceptibility to disease, and responses to vaccination and drug therapy1,2. Efforts to understand the influence of the microbiota on human health currently emphasize the identification of microbes associated with defined anatomic compartments (i.e., skin, gut, oral, etc.), as well as localized sites within these compartments3,4. Underpinning these investigative efforts is the rapid emergence and increased accessibility of next-generation sequencing (NGS) technologies that provide a massively parallel platform for analysis of the microbial genetic content (microbiome) of a sample. For many physiological samples, the associated microbiome is both complex and abundant (i.e., stool), but, for some samples, the microbiome is represented by low microbial biomass (i.e., human milk, lower respiratory tract) where sensitivity, experimental artefacts, and possible contamination become major issues. The common challenges of microbiome studies and appropriate experimental design have been the subject of multiple review articles5,6,7,8.
Presented herein is a robust NGS experimental pipeline based on targeted sequencing of the rRNA 16S V4 region9 to characterize the microbiome of human milk. Microbiome analysis of human milk is complicated not only by an inherently low microbial biomass10, but additionally by high levels of human DNA background11,12,13,14 and potential carryover of PCR inhibitors15,16 in extracted nucleic acid. This protocol relies on commercially available extraction kits and semi-automated platforms that can help minimize variability across sample preparation batches. It incorporates a well-defined bacterial mock community that is processed alongside samples as a quality control to validate each step in the protocol and provide an independent metric of pipeline robustness. Although the protocol as described is specific to the human milk samples, it is readily adaptable to other sample types including stool, rectal, vaginal, skin, areolar, and oral swabs10,17, and can serve as a starting point for researchers who wish to perform microbiome analyses.

<table border="0" cellpadding="0" cellspacing="0" width="956">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">AllPrep RNA/DNA Mini Kit</td>
			<td style="width:115px;">Qiagen</td>
			<td style="width:153px;">80204</td>
			<td style="width:395px;">DNA/RNA extraction kit</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Eliminase</td>
			<td style="width:115px;">Fisher Scientific</td>
			<td style="width:153px;">435532</td>
			<td>RNase, DNase, DNA decontaminant&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Thermo Mixer</td>
			<td style="width:115px;">Fisher Scientific</td>
			<td style="width:153px;"></td>
			<td>temperature-controlled vortexer&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Buffer RLT plus</td>
			<td style="width:115px;">Qiagen</td>
			<td>1053393</td>
			<td>guanidinium thiocyanate lysis buffer/ Part of Allprep kit</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">&#223;-Mercaptoethanol&#160;</td>
			<td style="width:115px;">Sigma Aldrich</td>
			<td>63689-25ML-F</td>
			<td>&#223;-ME is a reducing agent that will irreversibly denature RNases by reducing disulfide bonds</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">LME Beads</td>
			<td style="width:115px;">MP Biomedicals</td>
			<td>116914050</td>
			<td>bead tube</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">QIAgen TissueLyzer</td>
			<td style="width:115px;">Qiagen</td>
			<td>85300</td>
			<td>automated sample disruptor adapter set</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">QIAshredder column</td>
			<td style="width:115px;">Qiagen</td>
			<td>&#160;79654</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">QIAgen RB tube</td>
			<td style="width:115px;"></td>
			<td></td>
			<td>manufacturer&#39;s microcentrifuge tube in kit</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">QIAcube and related plasticware</td>
			<td style="width:115px;">Qiagen</td>
			<td>9001292</td>
			<td>automated DNA/RNA purification instrument</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">DNA exitus plus</td>
			<td style="width:115px;">Applichem</td>
			<td>A7089</td>
			<td>non-enzymatic decontamination solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">EB Buffer</td>
			<td style="width:115px;">Qiagen</td>
			<td style="width:153px;">19086</td>
			<td>elution buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">QIAgility and related plasticware</td>
			<td style="width:115px;">Qiagen</td>
			<td>9001532</td>
			<td>robotic liquid handler</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PCR water</td>
			<td style="width:115px;">MO BIO</td>
			<td>17000-</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">5PRIME HotMasterMix</td>
			<td style="width:115px;">Quantabio</td>
			<td>2200400</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Barcoded reverse primers</td>
			<td style="width:115px;">Eurofin</td>
			<td style="width:153px;">No Catalog #&#39;s</td>
			<td>designed and ordered</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">&#160;96 well PCR plate</td>
			<td style="width:115px;">USA scientific</td>
			<td style="width:153px;">1402-9708</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Tapestation 2200 and related plasticware</td>
			<td style="width:115px;">Agilent</td>
			<td>G2964AA</td>
			<td>automated DNA/RNA fragment analyzer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">D1000 reagents for Tapestation&#160;</td>
			<td style="width:115px;">Agilent</td>
			<td>5067-5585</td>
			<td>Sample buffer and ladder are part of this kit</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">OneStep PCR Inhibitor Removal Kit&#160;</td>
			<td style="width:115px;">Zymo Research</td>
			<td style="width:153px;">50444470</td>
			<td>PCR inhibitor removal is done per the manufacturer&#39;s instructions.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">QIAquick PCR Purification Kit</td>
			<td style="width:115px;">Qiagen</td>
			<td style="width:153px;">28104</td>
			<td>DNA clean up kit: silica-membrane-based purification of PCR products</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Qubit dsDNA HS Assay Kit</td>
			<td style="width:115px;">Thermo Fisher</td>
			<td style="width:153px;">Q32854</td>
			<td>dimethylsulfoxide-based dilution buffer and dye are part of this kit.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Qubit Fluorometer</td>
			<td style="width:115px;">Thermo Fisher</td>
			<td>Q33216</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">NanoDrop</td>
			<td style="width:115px;">Thermo Fisher</td>
			<td style="width:153px;"></td>
			<td>microvolume spectrophotometer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">MiSeq 300 V2 kit</td>
			<td style="width:115px;">Illumina</td>
			<td>15033624/15033626</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">MiSeq&#160;&#160;&#160;</td>
			<td style="width:115px;">Illumina</td>
			<td style="width:153px;">No Catalog #&#39;s</td>
			<td>next generation sequencer</td>
		</tr>
	</tbody>
</table>

a method for targeted 16s sequencing of human milk samples

Studies of microbial communities have become widespread with the development of relatively inexpensive, rapid, and high throughput sequencing. However, as with all these technologies, reproducible results depend on a laboratory workflow that incorporates appropriate precautions and controls. This is particularly important with low-biomass samples where contaminating bacterial DNA can generate misleading results. This article details a semi-automated workflow to identify microbes from human breast milk samples using targeted sequencing of the 16S ribosomal RNA (rRNA) V4 region on a low- to mid-throughput scale. The protocol describes sample preparation from whole milk including: sample lysis, nucleic acid extraction, amplification of the V4 region of the 16S rRNA gene, and library preparation with quality control measures. Importantly, the protocol and discussion consider issues that are salient to the preparation and analysis of low-biomass samples including appropriate positive and negative controls, PCR inhibitor removal, sample contamination by environmental, reagent, or experimental sources, and experimental best practices designed to ensure reproducibility. While the protocol as described is specific to human milk samples, it is adaptable to numerous low- and high-biomass sample types, including samples collected on swabs, frozen neat, or stabilized in a preservation buffer.

The protocol presented here includes important quality control (QC) steps to ensure that the data generated meet benchmarks for protocol sensitivity, specificity, and contamination control. The protocol&#39;s first QC step follows PCR amplification of the 16S V4 region (Figure 2). One &#181;L of PCR product from each sample was analyzed by electrophoresis to confirm that it was within the expected size range of 315 - 450 bp (Figure 2</str...

Watch this Scientific Journal Video about A Method for Targeted 16S Sequencing of Human Milk Samples at JoVE.com

A Method for Targeted 16S Sequencing of Human Milk Samples

A semi-automated workflow is presented for targeted sequencing of 16S rRNA from human milk and other low-biomass sample types.

Studies of microbial communities have become widespread with the development of relatively inexpensive, rapid, and high throughput sequencing. However, as ...

The overall goal of this method is to amplify 16 SRRNA from human milk and other low biomass samples using a semi-automated protocol. This method can help answer key questions in the development and perturbations of the human microbiome as it relates both to health and disease. The main advantage of the technique is that it's semi-automated, relatively easy to perform, and adaptable to multiple sample types including secretion, swabs, and stool.After thawing and alloquating whole milk according to the text protocol, spin the samples at 5000 times G and four degrees Celsius for 10 minutes to pellet the cells. Use a plastic spatula or large bore pipette tip to remove the top fat layer. Then without disturbing the pellet, remove all the supernatant, except for 100 microliters.With one milliliter of PBS, re-suspend and wash the pellet. Then prepare a negative control by adding one milliliter of sterile PBS to a five milliliter tube. Transfer the suspension to a clean one point five milliliter centrifuge tube and spin it at 5000 times G at room temperature for one minute.Then use a 1000 microliter sterile filtered pipette tip to discard the entire supernatant fatty layer. To disrupt and homogenize the sample, add 600 microliters of lysis buffer containing beta mercaptoethanol to the pellet and transfer the suspension to a bead tube. Prepare one positive control with lysis buffer and 20 microliters of the bacterial mock sample.Vortex all the bead tubes vigorously for 15 seconds. Then heat the samples on a temperature controlled vortexer at 37 degrees Celsius and 700 to 800 RPM for 10 minutes. Load the tubes into the automated sample disrupter adaptor set.Then bead beat the samples at 30 hertz for one minute. Disassemble the adaptor set and manually switch it with the sample plates from the left robotic arm to the right robotic arm of the instrument. Bead beat the tubes at 30 hertz for another minute then centrifuge the tubes at 17, 200 times G and 25 degrees Celsius for three minutes.Using a 200 microliter pipette, remove all of the supernatant, taking care not to take any of the fatty layer at the top or the bead residue at the bottom of the sample. Apply the supernatant to homogenizer columns. Then centrifuge the columns at maximum speed and 25 degrees Celsius for three minutes.Transfer 350 microliters of eluid to a two milliliter manufacturers microcentrifuge tube. For isolating DNA according to the text protocol, cut off the lids and smooth the edges of the individual spin columns for DNA and RNA. Insert the DNA spin column without the collection tube into the rotor adapter.Then discard the collection tube. Next, insert the vortexed two milliliter tubes into a shaker, following the automated DNA/RNA purification instrument's loading chart per the manufacturer's instructions. Label one point five milliliter collection tubes and insert them into rotor adapters.Then set the rotor adapters into the centrifuge following the automated DNA/RNA purification instrument's loading chart. After inserting filter tips, RNase free water, and the reagents into the instrument's reagent block, close the instrument's lid and run the custom DNA purification program on the instrument. When the reaction is complete, collect the sample containing tubes from the shaker, and if any sample is left, store it at minus 20 degrees Celsius for short term storage or minus 80 degrees Celsius for long term storage.After preparing the work area, and the PCR master mix, according to the text protocol, load 50 to 100 microliters of DNA samples into a 32-well instrument sample adapter, following the 96-well plate map. For each PCR plate, set up two negative controls by pipetting 30 microliters of PCR water in a clean one point five milliliter collection tube. Then place all the samples on the 32-well instrument sample adapter with caps locked in the open position.On the instrument's reagent adapter, remove the cap of each reverse primer with specific bar code numbers one at at time. To load the robotic liquid handler, place the reagent adapter in position B1.In order to avoid an edge effect, carefully place one edge of the adapter against the grip side and slowly bring the other edge down. Make sure to push on all the corners of the adapters.Place the sample adapter in position C1, making sure to push on all the corners of the adapters. Then vortex the five milliliter master mix. Open the cap and place it in position A on the instrument's master mix and reagent block.Place the PCR plate on the 96-well instrument's adapter that is intended to hold half skirted PCR plates. Then start the run and save it as a new file. When the run is complete, verify that there were no errors.Then use 12 or eight strip caps to seal the plate. Vortex vigorously and use a 96-well plate spinner to spin down the plates for one minute. Finally, place the plate on ice until it is moved to the post amplification room and loaded onto the thermal cycler.Following PCR amplification, carry out quality control and library preparation according to the text protocol. The protocol's first QC step follows PCR amplification of the 16SV4 region. As shown here, one microliter of PCR product from each sample, was analyzed by electrophoresis to confirm that it was within the expected size range of 350 to 450 base pairs.Some human milk samples generated lower amounts of specific product, suggesting either low levels of extracted microbial DNA in those samples or carryover of PCR inhibitors during extraction. Quantitation of specific product for each sample was essential for determining its required volume for equal molar pooling of samples for sequencing. A pooled library for targeted sequencing is usually dominated by a specific PCR product.If there is a significant amount of nonspecific product in the library, a gel purification step should be added to the workflow. Sequencing results demonstrate high diversity in the taxa associated with the human milk microbiome and variability in the number of sequencing reed counts for each sample. In contrast, the taxa composition and reed counts for the bacterial mock, were comparable to results obtained for the mock in previous workflow runs, suggesting that the observed variability for the human milk samples is an authentic experimental result and not a function of intrinsic workflow variability.If leaving a sequencer running overnight this technique can be done in two days, for 12 to 24 samples, if all samples amplify into the initial PCR run. If not, another shell day is needed. When attempting this procedure, it is important to travel only from the pre-PCR area to the post-PCR area to avoid contamination.It is also critical to change gloves frequently to avoid any cross contamination. Don't forget that working with human samples can be hazardous and precautions, such as proper protective equipment and bio safety cabinets, should always be used.

a-method-for-targeted-16s-sequencing-of-human-milk-samples

Research

JoVE Journal

Immunology and Infection

9.7K ビュー.  University of California at Los Angeles. The overall goal of this method is to amplify 16 SRRNA from human milk and other low biomass samples using a semi-automated protocol. This method can help answer key questions in the development and perturbations of the human microbiome as it relates both to health and disease. The main advantage of the technique is that it's semi-automated, relatively easy to perform, and adaptable to multiple sample types including secretion, swabs, and stool.After thawing and alloquating whole milk ...

ビデオ: A Method for Targeted 16S Sequencing of Human Milk Samples

A semi-automated workflow is presented for targeted sequencing of 16S rRNA from human milk and other low-biomass sample...

next-generation sequencing of 16s ribosomal rna gene amplicons

Next-generation Sequencing of 16S Ribosomal RNA Gene Amplicons

Characterizing microbial community has been a longstanding goal in environmental microbiology. Next-generation sequencing methods now allow for the characterization of microbial communities at an unprecedented depth with minimal cost and labor. We detail here our approach to sequence bacterial 16S ribosomal RNA genes using a benchtop sequencer.

guided protocol for fecal microbial characterization by 16s rrna-amplicon sequencing

Guided Protocol for Fecal Microbial Characterization by 16S rRNA-Amplicon Sequencing

This manuscript describes a detailed standardized protocol of high-throughput 16S rRNA-amplicon sequencing. The protocol introduces an integrated, uniformed, feasible, and inexpensive protocol starting from fecal sample collection through data analyses. This protocol enables analysis of large numbers of samples with rigorous standards and several...

comparative lesions analysis through a targeted sequencing approach

Comparative Lesions Analysis Through a Targeted Sequencing Approach

This article describes a method to identify clonal and subclonal alterations among different specimens from a given patient. Although the experiments described here focus on a specific tumor type, the approach is broadly applicable to other solid...

dissociation of human and mouse tumor tissue samples for single-cell rna sequencing

Author Spotlight: Exploring Strategies for Successful Immune Response Against Tumors

This protocol outlines the procedure for rapidly dissociating human and mouse tumor samples for single-cell RNA...

Dissociation of Human and Mouse Tumor Tissue Samples for Single-cell RNA Sequencing

efficient nucleic acid extraction and 16s rrna gene sequencing for bacterial community characterization

Efficient Nucleic Acid Extraction and 16S rRNA Gene Sequencing for Bacterial Community Characterization

We describe an efficient, robust, and cost effective method for extracting nucleic acid from swabs for characterization of bacterial communities using 16S rRNA gene amplicon sequencing. The method allows for a common processing approach for multiple sample types and accommodates a number of downstream analytic...

tick microbiome characterization by next-generation 16s rrna amplicon sequencing

Tick Microbiome Characterization by Next-Generation 16S rRNA Amplicon Sequencing

Here we present a next-generation sequencing protocol for 16S rRNA sequencing which enables identification and characterization of microbial communities within vectors. This method involves DNA extraction, amplification and barcoding of samples through PCR, sequencing on a flow-cell, and bioinformatics to match sequence data to phylogenetic...

targeted dna methylation analysis by next-generation sequencing

Targeted DNA Methylation Analysis by Next-generation Sequencing

Bisulfite amplicon sequencing (BSAS) is a method for quantifying cytosine methylation in targeted genomic regions of interest. This method uses bisulfite conversion paired with PCR amplification of target regions prior to next-generation sequencing to produce absolute quantitation of DNA methylation at a base-specific...

optimization for sequencing and analysis of degraded ffpe-rna samples

Optimization for Sequencing and Analysis of Degraded FFPE-RNA Samples

This method describes the steps to improve the quality and quantity of sequence data that can be obtained from formalin-fixed paraffin-embedded (FFPE) RNA samples. We describe the methodology to more accurately assess the quality of FFPE-RNA samples, prepare sequencing libraries, and analyze the data from FFPE-RNA...

identification of rare bacterial pathogens by 16s rrna gene sequencing and maldi-tof ms

Identification of Rare Bacterial Pathogens by 16S rRNA Gene Sequencing and MALDI-TOF MS

Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and molecular techniques (16S rRNA gene sequencing) permit the identification of rare bacterial pathogens in routine diagnostics. The goal of this protocol lies in the combination of both techniques which leads to more accurate and reliable...

single-cell nuclei isolation from homogenized human intermuscular adipose tissue samples for rna sequencing

Single-Cell Nuclei Isolation from Homogenized Human Intermuscular Adipose Tissue Samples for RNA Sequencing

microbiota analysis using two-step pcr and next-generation 16s rrna gene sequencing

Microbiota Analysis Using Two-step PCR and Next-generation 16S rRNA Gene Sequencing

Described here is a simplified standard operating procedure for microbiome profiling using 16S rRNA metagenomic sequencing and analysis using freely available tools. This protocol will help researchers who are new to the microbiome field as well as those requiring updates on methods to achieve bacterial profiling at a higher...

determination of sialic acids in liver and milk samples of wild-type and cmah knock-out mice.

Determination of Sialic Acids in Liver and Milk Samples of Wild-type and CMAH Knock-out Mice.

We describe a HPLC-based method for the determination of N-acetylneuraminic acid and N-glycolylenuraminic acid in mouse liver and...

Determination of Sialic Acids in Liver and Milk Samples of Wild-type and CMAH Knock-out Mice.

unbiased deep sequencing of rna viruses from clinical samples

Unbiased Deep Sequencing of RNA Viruses from Clinical Samples

This protocol describes a rapid and broadly applicable method for unbiased RNA-sequencing of viral samples from human clinical...

concentration of virus particles from environmental water and wastewater samples using skimmed milk flocculation and ultrafiltration

Concentration of Virus Particles from Environmental Water and Wastewater Samples Using Skimmed Milk Flocculation and Ultrafiltration

Virus concentration from environmental water and wastewater samples is a challenging task, carried out primarily for the identification and quantification of viruses. While several virus concentration methods have been developed and tested, we demonstrate here the effectiveness of ultrafiltration and skimmed milk flocculation for RNA viruses with different sample types.

pretargeted radioimmunotherapy: a method for targeted delivery of therapeutic radionuclides to tumors

This video describes the technique of pretargeted radioimmunotherapy or PRIT, in which immunoconjugates followed by radioligands are administered for treating tumors. This radioimmunotherapy reduces radiation doses to healthy tissues and utilizes radionuclides with very low half-lives incompatible with antibody-based...

Pretargeted Radioimmunotherapy: A Method for Targeted Delivery of Therapeutic Radionuclides to Tumors

targeted next-generation sequencing and bioinformatics pipeline to evaluate genetic determinants of constitutional disease

Targeted Next-generation Sequencing and Bioinformatics Pipeline to Evaluate Genetic Determinants of Constitutional Disease

Targeted next-generation sequencing is a time- and cost-efficient approach that is becoming increasingly popular in both disease research and clinical diagnostics. The protocol described here presents the complex workflow required for sequencing and the bioinformatics process used to identify genetic variants that contribute to...

virwatest, a point-of-use method for the detection of viruses in water samples

VirWaTest, A Point-of-Use Method for the Detection of Viruses in Water Samples

Here we present VirWaTest, which is a simple, affordable and portable method for the concentration and detection of viruses from water samples at the point of...

Genotypic Inference of HIV-1 Tropism Using Population-based Sequencing of V3

Background: Prior to receiving a drug from CCR5-antagonist class in HIV therapy, a patient must undergo an HIV tropism test to confirm that his or her viral population uses the CCR5 coreceptor for cellular entry, and not an alternative coreceptor. One approach to tropism testing is to examine the sequence of the V3 region of the HIV envelope, which interacts with the coreceptor.
Methods: Viral RNA is extracted from blood plasma. The V3 region is amplified in triplicate with nested reverse transcriptase-PCR. The amplifications are then sequenced and analyzed using the software, RE_Call. Sequences are then submitted to a bioinformatic algorithm such as geno2pheno to infer viral tropism from the V3 region. Sequences are inferred to be non-R5 if their geno2pheno false positive rate falls below 5.75%. If any one of the three sequences from a sample is inferred to be non-R5, the patient is unlikely to respond to a CCR5-antagonist.

HIV tropism can be inferred from the V3 region of the viral envelope. V3 is PCR amplified in triplicate using nested RT-PCR, sequenced, and interpreted using bioinformatic software. Samples with with 1 or more sequence(s) with low g2P scores are classified as non-R5 virus.

Background: Prior to receiving a drug from CCR5-antagonist class in HIV therapy, a patient must undergo an HIV tropism test to confirm that his or her ...

Averaging of Viral Envelope Glycoprotein Spikes from Electron Cryotomography Reconstructions using Jsubtomo

Enveloped viruses utilize membrane glycoproteins on their surface to mediate entry into host cells. Three-dimensional structural analysis of these glycoprotein &#8216;spikes&#8217; is often technically challenging but important for understanding viral pathogenesis and in drug design. Here, a protocol is presented for viral spike structure determination through computational averaging of electron cryo-tomography data. Electron cryo-tomography is a technique in electron microscopy used to derive three-dimensional tomographic volume reconstructions, or tomograms, of pleomorphic biological specimens such as membrane viruses in a near-native, frozen-hydrated state. These tomograms reveal structures of interest in three dimensions, albeit at low resolution. Computational averaging of sub-volumes, or sub-tomograms, is necessary to obtain higher resolution detail of repeating structural motifs, such as viral glycoprotein spikes. A detailed computational approach for aligning and averaging sub-tomograms using the Jsubtomo software package is outlined. This approach enables visualization of the structure of viral glycoprotein spikes to a resolution in the range of 20-40 &#197; and study of the study of higher order spike-to-spike interactions on the virion membrane. Typical results are presented for Bunyamwera virus, an enveloped virus from the family Bunyaviridae. This family is a structurally diverse group of pathogens posing a threat to human and animal health.

An approach is presented for determining structures of viral membrane glycoprotein complexes using a combination of electron cryo-tomography and sub-tomogram averaging with the computational package Jsubtomo.

Enveloped viruses utilize membrane glycoproteins on their surface to mediate entry into host cells. Three-dimensional structural analysis of these ...

There are a number of rare and, therefore, insufficiently described bacterial pathogens which are reported to cause severe infections especially in immunocompromised patients. In most cases only few data, mostly published as case reports, are available which investigate the role of such pathogens as an infectious agent. Therefore, in order to clarify the pathogenic character of such microorganisms, it is necessary to conduct epidemiologic studies which include large numbers of these bacteria. The methods used in such a surveillance study have to meet the following criteria: the identification of the strains has to be accurate according to the valid nomenclature, they should be easy to handle (robustness), economical in routine diagnostics and they have to generate comparable results among different laboratories. Generally, there are three strategies for identifying bacterial strains in a routine setting: 1) phenotypic identification characterizing the biochemical and metabolic properties of the bacteria, 2) molecular techniques such as 16S rRNA gene sequencing and 3) mass spectrometry as a novel proteome based approach. Since mass spectrometry and molecular approaches are the most promising tools for identifying a large variety of bacterial species, these two methods are described. Advances, limitations and potential problems when using these techniques are discussed.

Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and molecular techniques (16S rRNA gene sequencing) permit the identification of rare bacterial pathogens in routine diagnostics. The goal of this protocol lies in the combination of both techniques which leads to more accurate and reliable data.

There are a number of rare and, therefore, insufficiently described bacterial pathogens which are reported to cause severe infections especially in ...

A RAPID Method for Blood Processing to Increase the Yield of Plasma Peptide Levels in Human Blood

Research in the field of food intake regulation is gaining importance. This often includes the measurement of peptides regulating food intake. For the correct determination of a peptide&#39;s concentration, it should be stable during blood processing. However, this is not the case for several peptides which are quickly degraded by endogenous peptidases. Recently, we developed a blood processing method employing Reduced temperatures, Acidification, Protease inhibition, Isotopic exogenous controls and Dilution (RAPID) for the use in rats. Here, we have established this technique for the use in humans and investigated recovery, molecular form and circulating concentration of food intake regulatory hormones. The RAPID method significantly improved the recovery for 125I-labeled somatostatin-28 (+39%), glucagon-like peptide-1 (+35%), acyl ghrelin and glucagon (+32%), insulin and kisspeptin (+29%), nesfatin-1 (+28%), leptin (+21%) and peptide YY3-36 (+19%) compared to standard processing (EDTA blood on ice, p&#160;&#60;0.001). High performance liquid chromatography showed the elution of endogenous acyl ghrelin at the expected position after RAPID processing, while after standard processing 62% of acyl ghrelin were degraded resulting in an earlier peak likely representing desacyl ghrelin. After RAPID processing the acyl/desacyl ghrelin ratio in blood of normal weight subjects was 1:3 compared to 1:23 following standard processing (p&#160;= 0.03). Also endogenous kisspeptin levels were higher after RAPID compared to standard processing (+99%, p&#160;= 0.02). The RAPID blood processing method can be used in humans, yields higher peptide levels and allows for assessment of the correct molecular form.

The RAPID blood processing method can be used in humans and yields higher peptide levels as well as allows for assessment of the correct molecular form. Therefore, this method will be a valuable tool in peptide research.

Research in the field of food intake regulation is gaining importance. This often includes the measurement of peptides regulating food intake. For the ...

Swab Sampling Method for the Detection of Human Norovirus on Surfaces

Human noroviruses are a leading cause of epidemic and sporadic gastroenteritis worldwide. Because most infections are either spread directly via the person-to-person route or indirectly through environmental surfaces or food, contaminated fomites and inanimate surfaces are important vehicles for the spread of the virus during norovirus outbreaks.
We developed and evaluated a protocol using macrofoam swabs for the detection and typing of human noroviruses from hard surfaces. Compared with fiber-tipped swabs or antistatic wipes, macrofoam swabs allow virus recovery (range 1.2-33.6%) from toilet seat surfaces of up to 700 cm2. The protocol includes steps for the extraction of the virus from the swabs and further concentration of the viral RNA using spin columns. In total, 127 (58.5%) of 217 swab samples that had been collected from surfaces in cruise ships and long-term care facilities where norovirus gastroenteritis had been reported tested positive for GII norovirus by RT-qPCR. Of these 29 (22.8%) could be successfully genotyped. In conclusion, detection of norovirus on environmental surfaces using the protocol we developed may assist in determining the level of environmental contamination during outbreaks as well as detection of virus when clinical samples are not available; it may also facilitate monitoring of effectiveness of remediation strategies.

A macrofoam based sampling methodology was developed and evaluated for the detection and quantification of norovirus on environmental hard surfaces.

Human noroviruses are a leading cause of epidemic and sporadic gastroenteritis worldwide. Because most infections are either spread directly via the ...

Magnetic Stirrer Method for the Detection of Trichinella Larvae in Muscle Samples

Trichinellosis is a debilitating disease in humans and is caused by the consumption of raw or undercooked meat of animals infected with the nematode larvae of the genus Trichinella. The most important sources of human infections worldwide are game meat and pork or pork products. In many countries, the prevention of human trichinellosis is based on the identification of infected animals by means of the artificial digestion of muscle samples from susceptible animal carcasses.
There are several methods based on the digestion of meat but the magnetic stirrer method is considered the gold standard. This method allows the detection of Trichinella larvae by microscopy after the enzymatic digestion of muscle samples and subsequent filtration and sedimentation steps. Although this method does not require special and expensive equipment, internal controls cannot be used. Therefore, stringent quality management should be applied throughout the test. The aim of the present work is to provide detailed handling instructions and critical control points of the method to analysts, based on the experience of the European Union Reference Laboratory for Parasites and the National Reference Laboratory of Germany for Trichinella.

Magnetic Stirrer Method for the Detection of Trichinella Larvae in Muscle Samples

The prevention of human trichinellosis in many countries worldwide is based on the laboratory examination of muscle samples from susceptible animals by methods of digestion, of which the magnetic stirrer method is considered the gold standard.

Trichinellosis is a debilitating disease in humans and is caused by the consumption of raw or undercooked meat of animals infected with the nematode ...

Utilization of Capsules for Negative Staining of Viral Samples within Biocontainment

Transmission electron microscopy (TEM) is used to observe the ultrastructure of viruses and other microbial pathogens with nanometer resolution. Most biological materials do not contain dense elements capable of scattering electrons to create an image; therefore, a negative stain, which places dense heavy metal salts around the sample, is required. In order to visualize viruses in suspension under the TEM they must be applied to small grids coated with a transparent surface only nanometers thick. Due to their small size and fragility, these grids are difficult to handle and easily moved by air currents. The thin surface is easily damaged, leaving the sample difficult or impossible to image. Infectious viruses must be handled in a biosafety cabinet (BSC) and some require a biocontainment laboratory environment. Staining viruses in biosafety levels (BSL)-3 and -4 is especially challenging because these environments are more turbulent and technicians are required to wear personal protective equipment (PPE), which decreases dexterity. 
In this study, we evaluated a new device to assist in negative staining viruses in biocontainment. The device is a capsule that works as a specialized pipette tip. Once grids are loaded into the capsule, the user simply aspirates reagents into the capsule to deliver the virus and stains to the encapsulated grid, thus eliminating user handling of grids. Although this technique was designed specifically for use in BSL-3 or -4 biocontainment, it can ease sample preparation in any lab environment by enabling easy negative staining of virus. This same method can also be applied to prepare negative stained TEM specimens of nanoparticles, macromolecules and similar specimens.

This protocol provides instruction for negative staining virus samples which can easily be used in BSL-2, -3, or -4 laboratories. It includes the use of an innovative processing capsule, which protects the transmission electron microscopy grid and provides the user easier handling in the more turbulent environments within biocontainment.

Transmission electron microscopy (TEM) is used to observe the ultrastructure of viruses and other microbial pathogens with nanometer resolution. Most ...

Identification of Mouse and Human Antibody Repertoires by Next-Generation Sequencing

The immense adaptability of antigen recognition by antibodies is the basis of the acquired immune system. Despite our understanding of the molecular mechanisms underlying the production of the vast repertoire of antibodies by the acquired immune systems, it has not yet been possible to arrive at a global view of a complete antibody repertoire. In particular, B cell repertoires have been regarded as a black box because of their astronomical number of antibody clones. However, next-generation sequencing technologies are enabling breakthroughs to increase our understanding of the B cell repertoire. In this report, we describe a simple and efficient method to visualize and analyze whole individual mouse and human antibody repertoires. From the immune organs, representatively from spleen in mice and peripheral blood mononuclear cells in humans, total RNA was prepared, reverse transcribed, and amplified using the 5&#39;-RACE method. Using a universal forward primer and antisense primers for the antibody class-specific constant domains, antibody mRNAs were uniformly amplified in proportions reflecting their frequencies in the antibody populations. The amplicons were sequenced by next-generation sequencing (NGS), yielding more than 105 antibody sequences per immunological sample. We describe the protocols for antibody sequence analyses including V(D)J-gene-segment annotation, a bird&#39;s-eye view of the antibody repertoire, and our computational methods.

Here, we describe protocols for the analysis and visualization of the structure and constitution of whole antibody repertoires. This involves the acquisition of vast sequences of antibody RNA using next-generation sequencing.

The immense adaptability of antigen recognition by antibodies is the basis of the acquired immune system. Despite our understanding of the molecular ...

Viruses excreted by humans and animals may contaminate water sources and pose a risk to human health when this water is used for drinking, food irrigation, washing, etc. The classical fecal bacteria indicator does not always check for the presence of viral pathogens so the detection of viral pathogens and viral indicators is relevant in order to adopt measures of risk mitigation, especially in humanitarian scenarios and in areas where water-borne viral outbreaks are frequent.
At present, several commercial tests allowing the quantification of fecal indicator bacteria (FIB) are available for testing at the point of use. However, such commercial tests are not available for the detection of viruses. The detection of viruses in environmental water samples requires concentrating several liters into smaller volumes. Moreover, once concentrated, the detection of viruses relies on methods such as nucleic acid extraction and molecular detection (e.g., polymerase chain reaction [PCR]-based assays) of the viral genomes.
The method described here allows the concentration of viruses from 10 L water samples, as well as the extraction of viral nucleic acids at the point of use, with simple and portable equipment. This allows the testing of water samples at the point of use for several viruses and is useful in humanitarian scenarios, as well as at any context where an equipped laboratory is not available. Alternatively, the method allows concentrating viruses present in water samples and the shipping of the concentrate to a laboratory at room temperature for further analysis.

Here we present VirWaTest, which is a simple, affordable and portable method for the concentration and detection of viruses from water samples at the point of use.

Viruses excreted by humans and animals may contaminate water sources and pose a risk to human health when this water is used for drinking, food ...

Isolation of Leukocytes from Human Breast Milk for Use in an Antibody-dependent Cellular Phagocytosis Assay of HIV Targets

Even in the absence of antiretroviral drugs, only ~15% of infants breastfed by HIV-infected mothers become infected, suggesting a strong protective effect of breast milk (BM). Unless access to clean water and appropriate infant formula is reliable, the WHO does not recommend cessation of breastfeeding for HIV-infected mothers. Numerous factors likely work in tandem to reduce BM transmission. Breastfed infants ingest ~105&#8722;108 maternal leukocytes daily, though what remains largely unclear is the contribution of these cells to the antiviral qualities of BM. Presently we aimed to isolate cells from human BM in order to measure antibody-dependent cellular phagocytosis (ADCP), one of the most essential and pervasive innate immune responses, by BM phagocytes against HIV targets. Cells were isolated from 5 human BM samples obtained at various stages of lactation. Isolation was carried out via gentle centrifugation followed by careful removal of milk fat and repeated washing of the cell pellet. Fluorescent beads coated with HIV envelope (Env) epitope were used as targets for analysis of ADCP. Cells were stained with the CD45 surface marker to identify leukocytes. It was found that ADCP activity was significant above control experiments and reproducibly measurable using an HIV-specific antibody 830A.

Breast milk transmits human immunodeficiency virus (HIV), though only ~15% of infants breastfed by HIV-infected mothers become infected. Breastfed infants ingest ~105&#8722;108 maternal leukocytes daily, though these cells are understudied. Here we describe the isolation of breast milk leukocytes and an analysis of their phagocytic capacity.

Even in the absence of antiretroviral drugs, only ~15% of infants breastfed by HIV-infected mothers become infected, suggesting a strong protective effect ...