The authors are employees of Miltenyi Biotec GmbH, Germany.

To work under sterile conditions, it is recommended to perform all steps in a laminar flow hood.
1. Materials
<ol>
<li>HEPES buffer: 10 mM HEPES-NaOH pH 7.4, 150 mM NaCl, 5 mM KCl, 1 mM MgCl2, 1.8 mM CaCl2) </li>
<li>Collagenase D solution: Collagenase D: 100 mg/mL (Collagenase D &gt; 0.15 U/mg), in HEPES buffer </li>
<li>DNase I solution: 20,000 U/mL DNase I </li>
<li>PBS buffer at pH 7.2 </li>
<li>PEB buffer: 1 part BSA Stock Solution in 20 parts autoMACS Rinsing Solution </li>
<li>Tissue: lung derived from 6/7 week old adult female BALB/C mouse, free of adjoining organs.</li>
<li>Optional: CD11c MicroBeads, MACS MS Columns, MACS Separator for the isolation of dendritic cells from mouse lung single-cell suspension</li>
</ol>
2. Dissociating the lung tissue
<ol>
<li>Rinse tissue in a Petri dish containing PBS to remove erythrocytes. </li>
<li>Transfer a maximum of 450 mg lung tissue to a gentleMACS C Tube containing 4.9 mL HEPES buffer.</li>
<li>Add 100 &mu;L Collagenase D solution to a final concentration of 2 mg/ml Collagenase D.</li>
<li>Add 10 &mu;L DNase I solution for up to 150 mg tissue (final concentration of 40 U/ml DNase I) or 20 &mu;L DNase I for 150-450 mg lung tissue (final concentration of 80 U/mL DNase I).</li>
<li>Tightly close the C Tube and attach it onto the gentleMACS Dissociator. Then run the program "m_lung_01". </li>
<li>Incubate for 30 min at 37&deg;C with automated rotation or manually turning every 5 min.</li>
<li>Return sample to the gentleMACS Dissociator and run the program "m_lung_02".</li>
</ol>
3. Filtration
<ol>
<li>Prepare a 50 mL tube for collecting filtered cells by replacing the cap with a 70 &mu;m mesh cell strainer. </li>
<li>Once the second gentleMACS Program ends, depending on the distribution of sample material in the tube, you may centrifuge the tube briefly to collect the sample material at the bottom of the tube. </li>
<li>Remove the cells through the septum sealed cap of the C Tube using a suitable 1000 &mu;l pipette tip and apply them to the cell strainer. </li>
<li>Wash the cell strainer with 5 ml HEPES buffer at RT. </li>
<li>Centrifuge the cells to a pellet in a 50 mL tube at 300xg for 10 min. </li>
<li>Aspirate the supernatant and resuspend the cell pellet in your desired volume of PEB buffer.</li>
</ol>
Part 4: Representative Results:
<img src="/files/ftp_upload/1266/1266fig1.jpg" alt="Figure 1" /> Figure 1. Lung dissociation with the gentleMACS&trade; Dissociator resulted in 92% viable cells. Dead cells were fluorescently stained with propidium iodide (PI) ( right dot plot; left dot plot: no PI staining).
<img src="/files/ftp_upload/1266/1266fig2.jpg" alt="Figure 2" /> Figure 2. Dissociation of mouse lung tissue using the gentleMACS Dissociator results in a high percentage of viable leukocytes and endothelial cells. The derived single-cell suspensions were stained with CD45-PE and CD146-FITC or CD31-FITC and analyzed by flow cytometry.
<img src="/files/ftp_upload/1266/1266figure2c.png" alt="Figure 2C" /> Figure 3. Single-cell suspension derived from mouse lung tissue was stained with CD11c-FITC and Anti-mPDCA-1-APC to detect mouse CD11clow m-PDCA-1+ plasmacytoid DCs as well as CD11chigh cells.
 <img src="/files/ftp_upload/1266/1266fig4.jpg" alt="Figure 4" /> Figure 4. Enrichment of dendritic cells using CD11c MicroBeads, a MiniMACS Separator and two MS Columns.

<ol>
	<li>Swanson, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flt3-Ligand,+IL-4,+GM-CSF,+and+Adherence-Mediated+Isolation+of+Murine+Lung+Dendritic+Cells:+Assessment+of+Isolation+Technique+on+Phenotype+and+Function.">Flt3-Ligand, IL-4, GM-CSF, and Adherence-Mediated Isolation of Murine Lung Dendritic Cells: Assessment of Isolation Technique on Phenotype and Function.</a> J. Immunol. 173, 4875-4881 (2004).</li><li>Vermaelen, K., Pauwels, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accurate+and+simple+discrimination+of+mouse+pulmonary+dendritic+cell+and+macrophage+populations+by+flow+cytometry:+Methodology+and+new+insights.">Accurate and simple discrimination of mouse pulmonary dendritic cell and macrophage populations by flow cytometry: Methodology and new insights.</a> Cytometry Part A. 61A, 170-177 (2004).</li></ol>

The authors are employees of Miltenyi Biotec GmbH who make the instrument used in this article.

In this video, we introduce a new method for the dissociation of mouse lung tissue. We show that a combination of mechanical and enzymatic treatment of lung tissue yielded a high percentage of viable leukocytes and endothelial cells. Specifically, the mechanical disintegration of the tissue was achieved by the gentleMACS Dissociator. The gentleMACS C Tubes include a rotor - stator system, which dissociates tissue in a gentle way. The procedure is controlled by the program settings of the instrument. The settings were opt...

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		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
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<tr>
<td>C Tubes</td>
<td>&nbsp;</td>
<td>Miltenyi Biotec</td>
<td>Order no. 130-093-237</td>
<td><a href="http://www.miltenyibiotec.com/en/PG_709_765_gentleMACS_C_Tubes.aspx">http://www.miltenyibiotec.com/en/PG_709_765_gentleMACS_C_Tubes.aspx</a></td>
</tr>
<tr>
<td>gentleMACS&#x2122; Starting Kit</td>
<td>&nbsp;</td>
<td>Miltenyi Biotec</td>
<td>Order no. 130-093-235</td>
<td><a href="http://www.miltenyibiotec.com/en/PG_709_763_gentleMACS_Dissociator.aspx">http://www.miltenyibiotec.com/en/PG_709_763_gentleMACS_Dissociator.aspx</a></td>
</tr>
<tr>
<td>MACSmix&#x2122; Tube Rotator</td>
<td>&nbsp;</td>
<td>Miltenyi Biotec</td>
<td>Order no. 130-090-753</td>
<td><a href="http://www.miltenyibiotec.com/en/PG_34_251_MACSmix_Tube_Rotator.aspx">http://www.miltenyibiotec.com/en/PG_34_251_MACSmix_Tube_Rotator.aspx</a></td>
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<tr>
<td>autoMACS&#x2122; Rinsing Solution</td>
<td>&nbsp;</td>
<td>Miltenyi Biotec</td>
<td>Order no. 130-091-222</td>
<td><a href="http://www.miltenyibiotec.com/en/PG_134_155_autoMACS_Rinsing_Solution.aspx">http://www.miltenyibiotec.com/en/PG_134_155_autoMACS_Rinsing_Solution.aspx</a></td>
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<tr>
<td>MACS&#174; BSA Stock Solution</td>
<td>&nbsp;</td>
<td>Miltenyi Biotec</td>
<td>Order no. 130-091-376</td>
<td><a href="http://www.miltenyibiotec.com/en/PG_33_295_MACS_BSA_Stock_Solution.aspx">http://www.miltenyibiotec.com/en/PG_33_295_MACS_BSA_Stock_Solution.aspx</a></td>
</tr>
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<td>CD11c MicroBeads</td>
<td>&nbsp;</td>
<td>Miltenyi Biotec</td>
<td>Order No. 130-052-001</td>
<td><a href="http://www.miltenyibiotec.com/en/PG_93_132_CD11c_MicroBeads.aspx">http://www.miltenyibiotec.com/en/PG_93_132_CD11c_MicroBeads.aspx</a></td>
</tr>
<tr>
<td>CD11c-FITC, CD11c-PE</td>
<td>&nbsp;</td>
<td>Miltenyi Biotec</td>
<td>Order no. 130-092-026	130-091-830</td>
<td><a href="http://www.miltenyibiotec.com/en/PG_599_329_CD11c.aspx">http://www.miltenyibiotec.com/en/PG_599_329_CD11c.aspx</a></td>
</tr>
<tr>
<td>Anti-mPDCA-1-APC</td>
<td>&nbsp;</td>
<td>Miltenyi Biotec</td>
<td>Order no. 130-091-963</td>
<td><a href="http://www.miltenyibiotec.com/en/PG_599_325_Anti_mPDCA_1.aspx">http://www.miltenyibiotec.com/en/PG_599_325_Anti_mPDCA_1.aspx</a></td>
</tr>
<tr>
<td>CD146-FITC</td>
<td>&nbsp;</td>
<td>Miltenyi Biotec</td>
<td>Order no. 130-092-026</td>
<td><a href="http://www.miltenyibiotec.com/en/PG_599_417_CD146_LSEC_.aspx">http://www.miltenyibiotec.com/en/PG_599_417_CD146_LSEC_.aspx</a></td>
</tr>
<tr>
<td>CD45-PE</td>
<td>&nbsp;</td>
<td>Miltenyi Biotec</td>
<td>Order no. 130-091-610</td>
<td><a href="http://www.miltenyibiotec.com/en/PG_599_331_CD45.aspx">http://www.miltenyibiotec.com/en/PG_599_331_CD45.aspx</a></td>
</tr>
<tr>
<td>Propidium Iodide Solution</td>
<td>&nbsp;</td>
<td>Miltenyi Biotec</td>
<td>Order no. 130-093-233</td>
<td><a href="http://www.miltenyibiotec.com/en/PG_337_744_Propidium_Iodide_Solution.aspx">http://www.miltenyibiotec.com/en/PG_337_744_Propidium_Iodide_Solution.aspx</a></td>
</tr>
<tr>
<td>Art 1000 Reach Pipet Tips</td>
<td>&nbsp;</td>
<td>Molecular BioProducts</td>
<td>Order no. 2079</td>
<td><a href="http://www.mbpinc.com/ASP/products.aspx?query_TipID=61">http://www.mbpinc.com/ASP/products.aspx?query_TipID=61</a> <a href="http://www.mbpinc.com/html/products/art/display.html">http://www.mbpinc.com/html/products/art/display.html</a>
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standardized preparation of single-cell suspensions from mouse lung tissue using the gentlemacs dissociator

The preparation of single-cell suspensions from tissues is an important prerequisite for many experiments in cellular research. The process of dissociating whole organs requires specific parameters in order to obtain a high number of viable cells in a reproducible manner. The gentleMACS Dissociator optimizes this task with a simple, practical protocol. The instrument contains pre-programmed settings that are optimized for the efficient but gentle dissociation of a variety of tissue types, including mouse lungs. In this publication the use of the gentleMACS Dissociator on lung tissue derived from mice is demonstrated.

Watch this Scientific Journal Video about Standardized Preparation of Single-Cell Suspensions from Mouse Lung Tissue using the gentleMACS Dissociator at JoVE.com

Standardized Preparation of Single-Cell Suspensions from Mouse Lung Tissue using the gentleMACS Dissociator

Dissociating cells from specific tissue types requires specific parameters for tissue agitation to obtain a high volume of viable, culturable cells. The Miltenyi gentleMACS dissociator optimizes this task with a simple, practical protocol. In this publication the use of this apparatus on lung tissue is explained.

The preparation of single-cell suspensions from tissues is an important prerequisite for many experiments in cellular research. The process of ...

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Video: Standardized Preparation of Single-Cell Suspensions from Mouse Lung Tissue using the gentleMACS Dissociator

Preparation of Single-Cell Suspensions from Mouse Spleen with the gentleMACS Dissociator

Single-cell suspensions are a prerequisite for experiments in cell separation, cell analysis and cell culture.  To avoid tedious and often painful manual dissociations the gentleMACS Dissociator allows one to dissociate tissue very efficiently under controlled and reproducible conditions.  The gentleMACS Dissociator can optimally dissociate mouse spleen, combining timesaving and standardization with user-safety.

This video describes how to dissociate mouse spleens using the gentleMACS Dissociator, an automated bench-top device that can mechanically disrupt tissues using special tubes to produce viable cell suspensions. Following dissociation, spleens are filtered, centrifuged, and resuspended for further applications.

This video describes a simple, time-saving technique for automated tissue dissociation using the gentleMACS Dissociator to prepare single-cell suspensions of mouse splenocytes.

Single-cell suspensions are a prerequisite for experiments in cell separation, cell analysis and cell culture.  To avoid tedious and often painful manual ...

Generation of Single-Cell Suspensions from Mouse Neural Tissue

Within the nervous system, hundreds of neuronal and glial cell types have been described. Each specific cell type in the brain or spinal cord has a repertoire of cell surface molecules, or molecular determinants, through which it can be identified and characterized. Currently, robust cell identification and separation technologies require single-cell preparations to be generated while simultaneously limiting cell death and destruction of characteristic surface protein. The gentleMACS Dissociator, when used in combination with trypsin or papain-based dissociation kits, can effectively and gently dissociate brain tissue while preserving antigen epitopes and limiting cell loss. Standardized preparation of single-cell suspensions is achieved using C Tubes and optimized, preset gentleMACS Programs. Once generated, single-cell suspensions can be treated with monoclonal conjugates like Anti-Prominin-1 MicroBeads, which identify neural progenitors, or purified further using Myelin Removal Beads.

Dissociating cells from specific tissue types requires specific parameters for tissue aggitation to obtain a high volume of viable, culturable cells. The Miltenyi gentleMACS Dissociator optimizes this task with a simple, practical protocol. In this publication the use of this apparatus on nerual tissue is explained.

Within the nervous system, hundreds of neuronal and glial cell types have been described. Each specific cell type in the brain or spinal cord has a ...

Obtaining High Quality RNA from Single Cell Populations in Human Postmortem Brain Tissue

We proposed to investigate the gray matter reduction in the superior temporal gyrus seen in schizophrenia patients, by interrogating gene expression profiles of pyramidal neurons in layer III. It is well known that the cerebral cortex is an exceptionally heterogeneous structure comprising diverse regions, layers and cell types, each of which is characterized by distinct cellular and molecular compositions and therefore differential gene expression profiles. To circumvent the confounding effects of tissue heterogeneity, we used laser-capture microdissection (LCM) in order to isolate our specific cell-type i.e pyramidal neurons.
Approximately 500 pyramidal neurons stained with the Histogene staining solution were captured using the Arcturus XT LCM system. RNA was then isolated from captured cells and underwent two rounds of T7-based linear amplification using Arcturus/Molecular Devices kits. The Experion LabChip (Bio-Rad) gel and electropherogram indicated good quality a(m)RNA, with a transcript length extending past 600nt required for microarrays. The amount of mRNA obtained averaged 51&mu;g, with acceptable mean sample purity as indicated by the A260/280 ratio, of 2.5. Gene expression was profiled using the Human X3P GeneChip probe array from Affymetrix.

We describe a process using laser-capture microdissection to isolate and extract RNA from a homogeneous cell population, pyramidal neurons, in layer III of the superior temporal gyrus in postmortem human brains. We subsequently linearly amplify (T7-based) mRNA, and hybridize the sample to the Affymetrix human X3P microarray.

We proposed to investigate the gray matter reduction in the superior temporal gyrus seen in schizophrenia patients, by interrogating gene expression ...

Single-cell Suction Recordings from Mouse Cone Photoreceptors

Rod and cone photoreceptors in the retina are responsible for light detection. In darkness, cyclic nucleotide-gated (CNG) channels in the outer segment are open and allow cations to flow steadily inwards across the membrane, depolarizing the cell. Light exposure triggers the closure of the CNG channels, blocks the inward cation current flow, and thus results in cell hyperpolarization. Based on the polarity of photoreceptors, a suction recording method was developed in 1970s that, unlike the classic patch-clamp technique, does not require penetrating the plasma membrane 1. Drawing the outer segment into a tightly-fitting glass pipette filled with extracellular solution allows recording the current changes in individual cells upon test-flash exposure. However, this well-established "outer-segment-in (OS-in)" suction recording is not suitable for mouse cone recordings, because of the low percentage of cones in the mouse retina (3%) and the difficulties in identifying the cone outer segments. Recently, an inner-segment-in (IS-in) recording configuration was developed to draw the inner segment/nuclear region of the photoreceptor into the recording pipette 2,3. In this video, we will show how to record from individual mouse cone photoresponses using single-cell suction electrode.

We will show how to record flash responses from single mouse cones using a suction electrode.

Rod and cone photoreceptors in the retina are responsible for light detection. In darkness, cyclic nucleotide-gated (CNG) channels in the outer segment ...

Detection of Nitric Oxide and Superoxide Radical Anion by Electron Paramagnetic Resonance Spectroscopy from Cells using Spin Traps

Reactive nitrogen/oxygen species (ROS/RNS) at low concentrations play an important role in regulating cell function, signaling, and immune response but in unregulated concentrations are detrimental to cell viability1, 2. While living systems have evolved with endogenous and dietary antioxidant defense mechanisms to regulate ROS generation, ROS are produced continuously as natural by-products of normal metabolism of oxygen and can cause oxidative damage to biomolecules resulting in loss of protein function, DNA cleavage, or lipid peroxidation3, and ultimately to oxidative stress leading to cell injury or death4. 
Superoxide radical anion (O2&bull;-) is the major precursor of some of the most highly oxidizing species known to exist in biological systems such as peroxynitrite and hydroxyl radical. The generation of O2&bull;- signals the first sign of oxidative burst, and therefore, its detection and/or sequestration in biological systems is important. In this demonstration, O2&bull;- was generated from polymorphonuclear neutrophils (PMNs). Through chemotactic stimulation with phorbol-12-myristate-13-acetate (PMA), PMN generates O2&bull;- via activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase5. 
Nitric oxide (NO) synthase which comes in three isoforms, as inducible-, neuronal- and endothelial-NOS, or iNOS, nNOS or eNOS, respectively, catalyzes the conversion of L- arginine to L-citrulline, using NADPH to produce NO6. Here, we generated NO from endothelial cells. Under oxidative stress conditions, eNOS for example can switch from producing NO to O2&bull;- in a process called uncoupling, which is believed to be caused by oxidation of heme7 or the co-factor, tetrahydrobiopterin (BH4)8.
There are only few reliable methods for the detection of free radicals in biological systems but are limited by specificity and sensitivity. Spin trapping is commonly used for the identification of free radicals and involves the addition reaction of a radical to a spin trap forming a persistent spin adduct which can be detected by electron paramagnetic resonance (EPR) spectroscopy. The various radical adducts exhibit distinctive spectrum which can be used to identify the radicals being generated and can provide a wealth of information about the nature and kinetics of radical production9.
The cyclic nitrones, 5,5-dimethyl-pyrroline-N-oxide, DMPO10, the phosphoryl-substituted DEPMPO11, and the ester-substituted, EMPO12 and BMPO13, have been widely employed as spin traps--the latter spin traps exhibiting longer half-lives for O2&bull;- adduct. Iron (II)-N-methyl-D-glucamine dithiocarbamate, Fe(MGD)2 is commonly used to trap NO due to high rate of adduct formation and the high stability of the spin adduct14.

Electron paramagnetic resonance (EPR) spectroscopy was employed to detect nitric oxide from bovine aortic endothelial cells and superoxide radical anion from human neutrophils using iron (II)-N-methyl-D-glucamine dithiocarbamate, Fe(MGD)2 and 5,5-dimethyl-1-pyroroline-N-oxide, DMPO, respectively.

Reactive nitrogen/oxygen species (ROS/RNS) at low concentrations play an important role in regulating cell function, signaling, and immune response but in ...

Generation of Mice Derived from Induced Pluripotent Stem Cells

The production of induced pluripotent stem cells (iPSCs) from somatic cells provides a means to create valuable tools for basic research and may also produce a source of patient-matched cells for regenerative therapies. iPSCs may be generated using multiple protocols and derived from multiple cell sources. Once generated, iPSCs are tested using a variety of assays including immunostaining for pluripotency markers, generation of three germ layers in embryoid bodies and teratomas, comparisons of gene expression with embryonic stem cells (ESCs) and production of chimeric mice with or without germline contribution2. Importantly, iPSC lines that pass these tests still vary in their capacity to produce different differentiated cell types2. This has made it difficult to establish which iPSC derivation protocols, donor cell sources or selection methods are most useful for different applications.
The most stringent test of whether a stem cell line has sufficient developmental potential to generate all tissues required for survival of an organism (termed full pluripotency) is tetraploid embryo complementation (TEC)3-5. Technically, TEC involves electrofusion of two-cell embryos to generate tetraploid (4n) one-cell embryos that can be cultured in vitro to the blastocyst stage6. Diploid (2n) pluripotent stem cells (e.g. ESCs or iPSCs) are then injected into the blastocoel cavity of the tetraploid blastocyst and transferred to a recipient female for gestation (see Figure 1). The tetraploid component of the complemented embryo contributes almost exclusively to the extraembryonic tissues (placenta, yolk sac), whereas the diploid cells constitute the embryo proper, resulting in a fetus derived entirely from the injected stem cell line.
Recently, we reported the derivation of iPSC lines that reproducibly generate adult mice via TEC1. These iPSC lines give rise to viable pups with efficiencies of 5-13%, which is comparable to ESCs3,4,7 and higher than that reported for most other iPSC lines8-12. These reports show that direct reprogramming can produce fully pluripotent iPSCs that match ESCs in their developmental potential and efficiency of generating pups in TEC tests. At present, it is not clear what distinguishes between fully pluripotent iPSCs and less potent lines13-15. Nor is it clear which reprogramming methods will produce these lines with the highest efficiency. Here we describe one method that produces fully pluripotent iPSCs and "all- iPSC" mice, which may be helpful for investigators wishing to compare the pluripotency of iPSC lines or establish the equivalence of different reprogramming methods.

Generating induced pluripotent stem cell (iPSC) lines produces lines of differing developmental potential even when they pass standard tests for pluripotency. Here we describe a protocol to produce mice derived entirely from iPSCs, which defines the iPSC lines as possessing full pluripotency1.

The production of induced pluripotent stem cells (iPSCs) from somatic cells provides a means to create valuable tools for basic research and may also ...

Simple and Efficient Technique for the Preparation of Testicular Cell Suspensions

Mammalian testes are very complex organs that contain over 30 different cell types, including somatic testicular cells and different stages of germline cells. This heterogeneity is an important drawback concerning the study of the bases of mammalian spermatogenesis, as pure or enriched cell populations in certain stages of sperm development are needed for most molecular analyses1.
 Various strategies such as Staput2,3, centrifugal elutriation1, and flow cytometry (FC)4,5 have been employed to obtain enriched or purified testicular cell populations in order to enable differential gene expression studies. 
It is required that cells are in suspension for most enrichment/ purification approaches. Ideally, the cell suspension will be representative of the original tissue, have a high proportion of viable cells and few multinucleates - which tend to form because of the syncytial nature of the seminiferous epithelium6,7 - and lack cell clumps1 . Previous reports had evidenced that testicular cell suspensions prepared by an exclusively mechanical method clumped more easily than trypsinized ones1 . On the other hand, enzymatic treatments with RNAses and/or disaggregating enzymes like trypsin and collagenase lead to specific macromolecules degradation, which is undesirable for certain downstream applications. The ideal process should be as short as possible and involve minimal manipulation, so as to achieve a good preservation of macromolecules of interest such as mRNAs. Current protocols for the preparation of cell suspensions from solid tissues are usually time-consuming, highly operator-dependent, and may selectively damage certain cell types1,8 . 
	The protocol presented here combines the advantages of a highly reproducible and extremely brief mechanical disaggregation with the absence of enzymatic treatment, leading to good quality cell suspensions that can be used for flow cytometric analysis and sorting4, and ulterior gene expression studies9 .

A novel protocol for the mechanical preparation of testicular cell suspensions from rodent material, avoiding enzymes and detergents, is described. The method is very simple, fast, reproducible, and renders good quality cell suspensions, which are suitable for flow sorting and RNA extraction.

Mammalian testes are very complex organs that contain over 30 different cell types, including somatic testicular cells and different stages of germline ...

Quantifying Single Microvessel Permeability in Isolated Blood-perfused Rat Lung Preparation

The isolated blood-perfused lung preparation is widely used to visualize and define signaling in single microvessels. By coupling this preparation with real time imaging, it becomes feasible to determine permeability changes in individual pulmonary microvessels. Herein we describe steps to isolate rat lungs and perfuse them with autologous blood. Then, we outline steps to infuse fluorophores or agents via a microcatheter into a small lung region. Using these procedures described, we determined permeability increases in rat lung microvessels in response to infusions of bacterial lipopolysaccharide. The data revealed that lipopolysaccharide increased fluid leak across both venular and capillary microvessel segments. Thus, this method makes it possible to compare permeability responses among vascular segments and thus, define any heterogeneity in the response. While commonly used methods to define lung permeability require postprocessing of lung tissue samples, the use of real time imaging obviates this requirement as evident from the present method. Thus, the isolated lung preparation combined with real time imaging offers several advantages over traditional methods to determine lung microvascular permeability, yet is a straightforward method to develop and implement.

The isolated blood-perfused lung preparation makes it feasible to visualize microvessel networks on the lung surface. Here we describe an approach to quantify permeability of single microvessels in isolated lungs using real time fluorescence imaging.

The isolated blood-perfused lung preparation is widely used to visualize and define signaling in single microvessels. By coupling this preparation with ...

RNA Isolation from Mouse Pancreas: A Ribonuclease-rich Tissue

Isolation of high-quality RNA from ribonuclease-rich tissue such as mouse pancreas presents a challenge. As a primary function of the pancreas is to aid in digestion, mouse pancreas may contain as much a 75 mg of ribonuclease. We report modifications of standard phenol/guanidine thiocyanate lysis reagent protocols to isolate RNA from mouse pancreas. Guanidine thiocyanate is a strong protein denaturant and will effectively disrupt the activity of ribonuclease under most conditions. However, critical modifications to standard protocols are necessary to successfully isolate RNA from ribonuclease-rich tissues. Key steps include a high lysis reagent to tissue ratio, removal of undigested tissue prior to phase separation and inclusion of a ribonuclease inhibitor to the RNA solution. Using these and other modifications, we routinely isolate RNA with RNA Integrity Number (RIN) greater than 7. The isolated RNA is of suitable quality for routine gene expression analysis. Adaptation of this protocol to isolate RNA from ribonuclease rich tissues besides the pancreas should be readily achievable.

We report a procedure to isolate RNA with high integrity from the ribonuclease rich mouse pancreas.

Isolation of high-quality RNA from ribonuclease-rich tissue such as mouse pancreas presents a challenge.  As a primary function of the pancreas is to aid ...

Single-Cell Analysis of the Expression of Pseudomonas syringae Genes within the Plant Tissue

A plethora of pathogenic microorganisms constantly attack plants. The Pseudomonas syringae species complex encompasses Gram-negative plant-pathogenic bacteria of special relevance for a wide number of hosts. P. syringae enters the plant from the leaf surface and multiplies rapidly within the apoplast, forming microcolonies that occupy the intercellular space. The constitutive expression of fluorescent proteins by the bacteria allows for visualization of the microcolonies and monitoring of the development of the infection at the microscopic level. Recent advances in single-cell analysis have revealed the large complexity reached by clonal isogenic bacterial populations. This complexity, referred to as phenotypic heterogeneity, is the consequence of cell-to-cell differences in gene expression (not linked to genetic differences) among the bacterial community. To analyze the expression of individual loci at the single-cell level, transcriptional fusions to fluorescent proteins have been widely used. Under stress conditions, such as those occurring during colonization of the plant apoplast, P. syringae differentiates into distinct subpopulations based on the heterogeneous expression of key virulence genes (i.e., the Hrp type III secretion system). However, single-cell analysis of any given P. syringae population recovered from plant tissue is challenging due to the cellular debris released during the mechanical disruption intrinsic to the inoculation and bacterial extraction processes. The present report details a method developed to monitor the expression of P. syringae genes of interest at the single-cell level during the colonization of Arabidopsis and bean plants. The preparation of the plants and the bacterial suspensions used for inoculation using a vacuum chamber are described. The recovery of endophytic bacteria from infected leaves by apoplastic fluid extraction is also explained here. Both the bacterial inoculation and bacterial extraction methods are empirically optimized to minimize plant and bacterial cell damage, resulting in bacterial preparations optimal for microscopy and flow cytometry analysis.

Single-Cell Analysis of the Expression of Pseudomonas syringae Genes within the Plant Tissue

The present protocol describes a method that allows single-cell gene expression analysis on Pseudomonas syringae populations grown within the plant apoplast.

A plethora of pathogenic microorganisms constantly attack plants. The Pseudomonas syringae species complex encompasses Gram-negative plant-pathogenic ...