Name: a simple protocol for extracting hemocytes from wild caterpillars
Uploaded: 2012-11-15T11:00:00
Description: Watch this Scientific Journal Video about A Simple Protocol for Extracting Hemocytes from Wild Caterpillars at JoVE.com

TMS was supported by the Harlan Trust Fellowship (GWU) during this study. Funding for field collection and breeding L. fasciola and E. delphinii was provided by NSF grant DEB 0642438 to JTL.

1. Material Preparation
<ol>
	<li>Prepare needles (1-2 &mu;m tip and 3-4 mm taper) using borosilicate glass capillary tubes and a micropipette puller. Instrument settings: ramp: 561; velocity: 20; heat: 560; delay: 1; pull: 100; pressure: 500.</li>
	<li>Prepare the collection solution: 60% of Grace's Medium (GM) supplemented with 10% of Fetal Bovine Serum (FBS) and 20% of Anticoagulant Buffer (98 mM NaOH, 186 mM NaCI, 1.7 mM EDTA and 41 mM citric acid, pH 4.5). The above solution is prepared fresh under sterile conditi...

<ol>
	<li>Hartenstein, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blood+cells+and+blood+cell+development+in+the+animal+kingdom.">Blood cells and blood cell development in the animal kingdom.</a> Annu. Rev. Cell Dev. Biol. 22, 677 (2006).</li><li>Wood, W., Jacinto, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+melanogaster+embryonic+haemocytes:+masters+of+multitasking.">Drosophila melanogaster embryonic haemocytes: masters of multitasking.</a> Nat. Rev. Mol. Cell Biol. 8 (7), 542 (2007).</li><li>Strand, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+insect+cellular+immune+response.">The insect cellular immune response.</a> Insect Sci. 15 (1), 1 (2008).</li><li>Fauvarque, M. O., Williams, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+cellular+immunity:+a+story+of+migration+and+adhesion.">Drosophila cellular immunity: a story of migration and adhesion.</a> J. Cell Sci. 124 (9), 1373 (2011).</li><li>Nehme, N. T., Quintin, J., Cho, J. H., Lee, J., Lafarge, M. C., Kocks, C., Ferrandon, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relative+roles+of+the+cellular+and+humoral+responses+in+the+Drosophila+host+defense+against+three+gram-positive+bacterial+infections.">Relative roles of the cellular and humoral responses in the Drosophila host defense against three gram-positive bacterial infections.</a> PLoS One. 6 (3), e14743 (2011).</li><li>Ulvila, J., Vanha-Aho, L. M., R&#228;met, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+phagocytosis+-+still+many+unknowns+under+the+surface.">Drosophila phagocytosis - still many unknowns under the surface.</a> APMIS. 119 (10), 651 (2011).</li><li>Moreira, C. G., Regan, J. C., Zaidman-Remy, A., Jacinto, A., Praq, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+hemocyte+migration:+an+in+vivo+assay+for+directional+cell+migration.">Drosophila hemocyte migration: an in vivo assay for directional cell migration.</a> Methods Mol. Biol. 769, 249 (2011).</li><li>Hillyer, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mosquito+immunity.">Mosquito immunity.</a> Adv. Exp. Med. Biol. 708, 218 (2010).</li><li>Castillo, J. C., Robertson, A. E., Strand, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+hemocytes+from+the+mosquitoes+Anopheles+gambiae+and+Aedes+aegypti.">Characterization of hemocytes from the mosquitoes Anopheles gambiae and Aedes aegypti.</a> Insect Biochem. Mol. Biol. 36 (12), 891 (2006).</li><li>Jiang, H., Vilcinskas, A., Kanost, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunity+in+lepidopteran+insects.">Immunity in lepidopteran insects.</a> Adv. Exp. Med. Biol. 708, 181 (2010).</li><li>Eleftherianos, I., Xu, M., Yadi, H., ffrench-Constant, R. H., Reynolds, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasmatocyte-spreading+peptide+(PSP)+plays+a+central+role+in+insect+cellular+immune+defenses+against+bacterial+infection.">Plasmatocyte-spreading peptide (PSP) plays a central role in insect cellular immune defenses against bacterial infection.</a> J. Exp. Biol. 212 (12), 1840 (2009).</li><li>Ribeiro, C., Breh&#233;lin, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insect+haemocytes:+what+type+of+cell+is+that.">Insect haemocytes: what type of cell is that.</a> J. Insect Physiol. 52 (5), 417 (2006).</li><li>Beetz, S., Brinkmann, M., Trenczek, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differences+between+larval+and+pupal+hemocytes+of+the+tobacco+hornworm,+Manduca+sexta,+determined+by+monoclonal+antibodies+and+density+centrifugation.">Differences between larval and pupal hemocytes of the tobacco hornworm, Manduca sexta, determined by monoclonal antibodies and density centrifugation.</a> J. Insect Physiol. 50 (9), 805 (2004).</li><li>Beetz, S., Holthusen, T. K., Koolman, J., Trenczek, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlation+of+hemocyte+counts+with+different+developmental+parameters+during+the+last+larval+instar+of+the+tobacco+hornworm,+Manduca+sexta.">Correlation of hemocyte counts with different developmental parameters during the last larval instar of the tobacco hornworm, Manduca sexta.</a> Arch. Insect Biochem. Physiol. 67 (2), 63 (2008).</li><li>Eleftherianos, I., Joyce, S., ffrench-Constant, R. H., Clarke, D. J., Reynolds, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+the+tri-trophic+interaction+between+insects,+nematodes+and+Photorhabdus.">Probing the tri-trophic interaction between insects, nematodes and Photorhabdus.</a> Parasitology. 137 (11), 1695 (2010).</li><li>Qayum, A. A., Telang, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Protocol+for+Collecting+and+Staining+Hemocytes+from+the+Yellow+Fever+Mosquito+Aedes+aegypti.">A Protocol for Collecting and Staining Hemocytes from the Yellow Fever Mosquito Aedes aegypti.</a> J. Vis. Exp. (51), e2772 (2011).</li></ol>

Methods for extracting hemocytes from medically important insects and lepidopteran model insects have previously been reported 9, 14. Hemocyte extraction methods are adapted according to the insect species, the developmental stage of the insect and its morphological features. For example, hemolymph isolation from Manduca larvae can be readily performed by snipping the curved horn near the end of the abdomen 15. Because slug caterpillars (Limacodidae) lack this abdominal structure, we have d...

<table border="1">
<tbody>
 <tr>
 <td>Name of the reagent</td>
 <td>Company</td>
 <td>Catalogue number</td>
 <td>Comments</td>
 </tr>
 <tr>
 <td>Micropipette puller</td>
 <td>Sutter Instruments</td>
 <td>P-1000 </td>
 <td></td>
 </tr>
 <tr>
 <td>Borosilicate glass tubes</td>
 <td>Sutter Instruments</td>
 <td>B100-50-10 </td>
 <td>OD: 1.0, ID: 0.50 mm</td>
 </tr>
 <tr>
 <td>Grace's Medium</td>
 <td>Sigma</td>
 <td>G8142</td>
 <td></td>
 </tr>
 <tr>
 <td>Fetal Bovine Serum </td>
 <td>Thermo Fisher Scientific</td>
 <td>SH3007102</td>
 <td>Heat inactivated</td>
 </tr>
 <tr>
 <td>Dumont #5 Forceps</td>
 <td>Fine science tools</td>
 <td>11252-40 </td>
 <td></td>
 </tr>
 <tr>
 <td>Neubauer hemocytometer</td>
 <td>Hausser Scientific</td>
 <td>3200 </td>
 <td></td>
 </tr>
 <tr>
 <td>Plastic tubing</td>
 <td>Tri-Tech</td>
 <td>TT-3-32OD </td>
 <td>OD: 3/32'', ID: 1/32'</td>
 </tr>
 <tr>
 <td>Glass medical syringe</td>
 <td>Fortuna Optima</td>
 <td>D-97877 </td>
 <td>50 ml volume</td>
 </tr>
 <tr>
 <td>Blunt end needle</td>
 <td>Small Parts</td>
 <td>NE-162PL-25 </td>
 <td>16 Gauge x 1" length </td>
 </tr>
 </tbody>
</table>

a simple protocol for extracting hemocytes from wild caterpillars

Insect hemocytes (equivalent to mammalian white blood cells) play an important role in several physiological processes throughout an insect's life cycle 1. In larval stages of insects belonging to the orders of Lepidoptera (moths and butterflies) and Diptera (true flies), hemocytes are formed from the lymph gland (a specialized hematopoietic organ) or embryonic cells and can be carried through to the adult stage. Embryonic hemocytes are involved in cell migration during development and chemotaxis regulation during inflammation. They also take part in cell apoptosis and are essential for embryogenesis 2. Hemocytes mediate the cellular arm of the insect innate immune response that includes several functions, such as cell spreading, cell aggregation, formation of nodules, phagocytosis and encapsulation of foreign invaders 3. They are also responsible for orchestrating specific insect humoral defenses during infection, such as the production of antimicrobial peptides and other effector molecules 4, 5. Hemocyte morphology and function have mainly been studied in genetic or physiological insect models, including the fruit fly, Drosophila melanogaster 6, 7, the mosquitoes Aedes aegypti and Anopheles gambiae 8, 9 and the tobacco hornworm, Manduca sexta 10, 11. However, little information currently exists about the diversity, classification, morphology and function of hemocytes in non-model insect species, especially those collected from the wild 12.
Here we describe a simple and efficient protocol for extracting hemocytes from wild caterpillars. We use penultimate instar Lithacodes fasciola (yellow-shouldered slug moth) (Figure 1) and Euclea delphinii (spiny oak slug) caterpillars (Lepidoptera: Limacodidae) and show that sufficient volumes of hemolymph (insect blood) can be isolated and hemocyte numbers counted from individual larvae. This method can be used to efficiently study hemocyte types in these species as well as in other related lepidopteran caterpillars harvested from the field, or it can be readily combined with immunological assays designed to investigate hemocyte function following infection with microbial or parasitic organisms 13.

The protocol described herein allows the collection of a minimum volume of 10-20 &mu;l of insect hemolymph from individual caterpillars. Hemocytes collected using this method are free of cell clumping, melanization defects, tissue debris or other contaminants. Therefore hemocytes can be readily observed and counted under the microscope, and several insects can be observed within a few hosur. We observed that the majority of hemocytes in our samples consisted of plasmatocytes 3 (hemocytes spreading asymmetrical...

Watch this Scientific Journal Video about A Simple Protocol for Extracting Hemocytes from Wild Caterpillars at JoVE.com

A Simple Protocol for Extracting Hemocytes from Wild Caterpillars

Insect hemocytes carry out many important functions, both immune and non-immune, throughout all stages of insect development. Our present knowledge of hemocyte types and function comes from studies on insect genetic models. Here, we present a method for extracting, quantifying and visualizing hemocytes from wild caterpillars.

Insect hemocytes (equivalent to mammalian white blood cells) play an important role in several physiological processes throughout an insect's life cycle ...

a-simple-protocol-for-extracting-hemocytes-from-wild-caterpillars

Research

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Biology

Extracting DNA from the Gut Microbes of the Termite (Zootermopsis Angusticollis) and Visualizing Gut Microbes

Termites are among the few animals known to have the capacity to subsist solely by consuming wood.  The termite gut tract contains a dense and species-rich microbial population that assists in the degradation of lignocellulose predominantly into acetate, the key nutrient fueling termite metabolism (Odelson &amp; Breznak, 1983).  Within these microbial populations are bacteria, methanogenic archaea and, in some ("lower") termites, eukaryotic protozoa. Thus, termites are excellent research subjects for studying the interactions among microbial species and the numerous biochemical functions they perform to the benefit of their host.  The species composition of microbial populations in termite guts as well as key genes involved in various biochemical processes has been explored using molecular techniques (Kudo et al., 1998; Schmit-Wagner et al., 2003; Salmassi &amp; Leadbetter, 2003). These techniques depend on the extraction and purification of high-quality nucleic acids from the termite gut environment.  The extraction technique described in this video is a modified compilation of protocols developed for extraction and purification of nucleic acids from environmental samples (Mor  et al., 1994; Berthelet et al., 1996; Purdy et al., 1996; Salmassi &amp; Leadbetter, 2003; Ottesen et al. 2006) and it produces DNA from termite hindgut material suitable for use as template for polymerase chain reaction (PCR).

Extracting DNA from the Gut Microbes of the Termite Zootermopsis Angusticollis and Visualizing Gut Microbes

This video illustrates the technique for extracting DNA from the species of microbes resident in the termite hindgut. The preparation of a wet mount slide, which is useful for visualizing the gut microbial community is also illustrated, and a tour through the species-rich gut environment is given.

Termites are among the few animals known to have the capacity to subsist solely by consuming wood.  The termite gut tract contains a dense and ...

Protocol for Mosquito Rearing (A. gambiae)

This protocol describes mosquito rearing in the insectary. The insectary rooms are maintained at 28&deg;C and ~80% humidity, with a 12 hr. day/night cycle. For this procedure, you'll need mosquito cages, 10% sterile sucrose solution, paper towels, beaker, whatman filter paper, glass feeders, human blood and serum, water bath, parafilm, distilled water, clean plastic trays, mosquito food (described below), mosquito net to cover the trays, vacuum, and a collection chamber to collect adults.

Protocol for Mosquito Rearing A. gambiae

This video illustrates the general techniques used to rear Anopheles gambiae in the laboratory. The methods for caring for laboratory mosquitoes are demonstrated through all stages of the organism's life cycle from larvae to pupae to blood-feeding adults.

This protocol describes mosquito rearing in the insectary. The insectary rooms are maintained at 28&deg;C and ~80% humidity, with a 12 hr. day/night ...

Pyrosequencing: A Simple Method for Accurate Genotyping

Pharmacogenetic research benefits first-hand from the abundance of information provided by the completion of the Human Genome Project. With such a tremendous amount of data available comes an explosion of genotyping methods. Pyrosequencing(R) is one of the most thorough yet simple methods to date used to analyze polymorphisms. It also has the ability to identify tri-allelic, indels, short-repeat polymorphisms, along with determining allele percentages for methylation or pooled sample assessment. In addition, there is a standardized control sequence that provides internal quality control. This method has led to rapid and efficient single-nucleotide polymorphism evaluation including many clinically relevant polymorphisms. The technique and methodology of Pyrosequencing is explained.


Pyrosequencing(R) is one of the most thorough yet simple methods to date used to analyze polymorphisms. This method has led to rapid and efficient single-nucleotide polymorphism evaluation including many clinically relevant polymorphisms. The technique and methodology of Pyrosequencing is explained.

Pharmacogenetic research benefits first-hand from the abundance of information provided by the completion of the Human Genome Project. With such a ...

Protocol for Culturing Sympathetic Neurons from Rat Superior Cervical Ganglia (SCG)

The superior cervical ganglia (SCG) in rats are small, glossy, almond-shaped structures that contain sympathetic neurons.  These neurons provide sympathetic innervations for the head and neck regions and they constitute a well-characterized and relatively homogeneous population (4).  Sympathetic neurons are dependent on nerve growth factor (NGF) for survival, differentiation and axonal growth and the wide-spread availability of NGF facilitates their culture and experimental manipulation (2, 3, 6).  For these reasons, cultured sympathetic neurons have been used in a wide variety of studies including neuronal development and differentiation, mechanisms of programmed and pathological cell death, and signal transduction (1, 2, 5, and 6).  Dissecting out the SCG from newborn rats and culturing sympathetic neurons is not very complicated and can be mastered fairly quickly.  In this article, we will describe in detail how to dissect out the SCG from newborn rat pups and to use them to establish cultures of sympathetic neurons.  The article will also describe the preparatory steps and the various reagents and equipment that are needed to achieve this.

Protocol for Culturing Sympathetic Neurons from Rat Superior Cervical Ganglia SCG

This is a protocol describing how to isolate and culture primary sympathetic neurons from superior cervical ganglia (SCG) of newborn rat pups.

The superior cervical ganglia (SCG) in rats are small, glossy, almond-shaped structures that contain sympathetic neurons.  These neurons provide ...

A PCR-based Genotyping Method to Distinguish Between Wild-type and Ornamental Varieties of Imperata cylindrica

Wild-type I. cylindrica (cogongrass) is one of the top ten worst invasive plants in the world, negatively impacting agricultural and natural resources in 73 different countries throughout Africa, Asia, Europe, New Zealand, Oceania and the Americas1-2. Cogongrass forms rapidly-spreading, monodominant stands that displace a large variety of native plant species and in turn threaten the native animals that depend on the displaced native plant species for forage and shelter. To add to the problem, an ornamental variety [I. cylindrica var. koenigii (Retzius)] is widely marketed under the names of Imperata cylindrica 'Rubra', Red Baron, and Japanese blood grass (JBG). This variety is putatively sterile and noninvasive and is considered a desirable ornamental for its red-colored leaves. However, under the correct conditions, JBG can produce viable seed (Carol Holko, 2009 personal communication) and can revert to a green invasive form that is often indistinguishable from cogongrass as it takes on the distinguishing characteristics of the wild-type invasive variety4 (Figure 1). This makes identification using morphology a difficult task even for well-trained plant taxonomists. Reversion of JBG to an aggressive green phenotype is also not a rare occurrence. Using sequence comparisons of coding and variable regions in both nuclear and chloroplast DNA, we have confirmed that JBG has reverted to the green invasive within the states of Maryland, South Carolina, and Missouri. JBG has been sold and planted in just about every state in the continental U.S. where there is not an active cogongrass infestation. The extent of the revert problem in not well understood because reverted plants are undocumented and often destroyed.
Application of this molecular protocol provides a method to identify JBG reverts and can help keep these varieties from co-occurring and possibly hybridizing. Cogongrass is an obligate outcrosser and, when crossed with a different genotype, can produce viable wind-dispersed seeds that spread cogongrass over wide distances5-7. JBG has a slightly different genotype than cogongrass and may be able to form viable hybrids with cogongrass. To add to the problem, JBG is more cold and shade tolerant than cogongrass8-10, and gene flow between these two varieties is likely to generate hybrids that are more aggressive, shade tolerant, and cold hardy than wild-type cogongrass. While wild-type cogongrass currently infests over 490 million hectares worldwide, in the Southeast U.S. it infests over 500,000 hectares and is capable of occupying most of the U.S. as it rapidly spreads northward due to its broad niche and geographic potential3,7,11. The potential of a genetic crossing is a serious concern for the USDA-APHIS Federal Noxious Week Program. Currently, the USDA-APHIS prohibits JBG in states where there are major cogongrass infestations (e.g., Florida, Alabama, Mississippi). However, preventing the two varieties from combining can prove more difficult as cogongrass and JBG expand their distributions. Furthermore, the distribution of the JBG revert is currently unknown and without the ability to identify these varieties through morphology, some cogongrass infestations may be the result of JBG reverts. Unfortunately, current molecular methods of identification typically rely on AFLP (Amplified Fragment Length Polymorphisms) and DNA sequencing, both of which are time consuming and costly. Here, we present the first cost-effective and reliable PCR-based molecular genotyping method to accurately distinguish between cogongrass and JBG revert.

A PCR-based Genotyping Method to Distinguish Between Wild-type and Ornamental Varieties of Imperata cylindrica

We provide a cost-effective and rapid molecular genotyping protocol that employs variety-specific PCR primers that target DNA sequence differences within the chloroplast trnL-F spacer region to differentiate between varieties of Imperata cylindrica (cogongrass) that cannot be distinguished by morphology alone. These varieties include the federally listed noxious weed, cogongrass and closely-related, wide-spread ornamental variety, I. cylindrica var. koenigii (Japanese blood grass).

Wild-type I. cylindrica (cogongrass) is one of the top ten worst invasive plants in the world, negatively impacting agricultural and natural resources in ...

SIVQ-LCM Protocol for the ArcturusXT Instrument

SIVQ-LCM is a new methodology that automates and streamlines the more traditional, user-dependent laser dissection process.&#160;It aims to create an advanced, rapidly customizable laser dissection platform technology. In this report, we describe the integration of the image analysis software Spatially Invariant Vector Quantization (SIVQ) onto the ArcturusXT instrument. The ArcturusXT system contains both an infrared (IR) and ultraviolet (UV) laser, allowing for specific cell or large area dissections. The principal goal is to improve the speed, accuracy, and reproducibility of the laser dissection to increase sample throughput. This novel approach facilitates microdissection of both animal and human tissues in research and clinical workflows.

SIVQ-LCM is an innovative approach that harnesses a computer algorithm, Spatially Invariant Vector Quantization (SIVQ), to drive the laser capture microdissection (LCM) process. The SIVQ-LCM workflow greatly improves the speed and accuracy of microdissection, with applications in both the research and clinical settings.

SIVQ-LCM is a new methodology that automates and streamlines the more traditional, user-dependent laser dissection process.&#160;It aims to create an ...

A Simple Bioassay for the Evaluation of Vascular Endothelial Growth Factors

The analysis of receptor tyrosine kinases and their interacting ligands involved in vascular biology is often challenging due to the constitutive expression of families of related receptors, a broad range of related ligands and the difficulty of dealing with primary cultures of specialized endothelial cells. Here we describe a bioassay for the detection of ligands to the vascular endothelial growth factor receptor-2 (VEGFR-2), a key transducer of signals that promote angiogenesis and lymphangiogenesis. A cDNA encoding a fusion of the extracellular (ligand-binding) region of VEGFR-2 with the transmembrane and cytoplasmic regions of the erythropoietin receptor (EpoR) is expressed in the factor-dependent cell line Ba/F3. This cell line grows in the presence of interleukin-3 (IL-3) and withdrawal of this factor results in death of the cells within 24 hr. Expression of the VEGFR-2/EpoR receptor fusion provides an alternative mechanism to promote survival and potentially proliferation of stably transfected Ba/F3 cells in the presence of a ligand capable of binding and cross-linking the extracellular portion of the fusion protein (i.e., one that can cross-link the VEGFR-2 extracellular region). The assay can be performed in two ways: a semi-quantitative approach in which small volumes of ligand and cells permit a rapid result in 24 hr, and a quantitative approach involving surrogate markers of a viable cell number. The assay is relatively easy to perform, is highly responsive to known VEGFR-2 ligands and can accommodate extracellular inhibitors of VEGFR-2 signaling such as monoclonal antibodies to the receptor or ligands, and soluble ligand traps.

We describe a simple cell-based bioassay for detecting, quantifying and monitoring the activity of members of the vascular endothelial growth factor family of ligands. The assay uses chimeric receptors expressed in a factor-dependent cell line to provide a semi-quantitative or quantitative assessment of receptor binding and cross-linking by the ligand.

The analysis of receptor tyrosine kinases and their interacting ligands involved in vascular biology is often challenging due to the constitutive ...

Filtration Isolation of Nucleic Acids:  A Simple and Rapid DNA Extraction Method

FINA, filtration isolation of nucleic acids, is a novel extraction method which utilizes vertical filtration via a separation membrane and absorbent pad to extract cellular DNA from whole blood in less than 2 min. The blood specimen is treated with detergent, mixed briefly and applied by pipet to the separation membrane. The lysate wicks into the blotting pad due to capillary action, capturing the genomic DNA on the surface of the separation membrane. The extracted DNA is retained on the membrane during a simple wash step wherein PCR inhibitors are wicked into the absorbent blotting pad. The membrane containing the entrapped DNA is then added to the PCR reaction without further purification. This simple method does not require laboratory equipment and can be easily implemented with inexpensive laboratory supplies. Here we describe a protocol for highly sensitive detection and quantitation of HIV-1 proviral DNA from 100 &#181;l whole blood as a model for early infant diagnosis of HIV that could readily be adapted to other genetic targets.

We describe here a simple and rapid paper-based DNA extraction method of HIV proviral DNA from whole blood detected by quantitative PCR. This protocol can be extended for use in detecting other genetic markers or using alternative amplification methods.

FINA, filtration isolation of nucleic acids, is a novel extraction method which utilizes vertical filtration via a separation membrane and absorbent pad ...

A Method for Extracting Pigments from Squid Doryteuthis pealeii

Cephalopods can undergo rapid and adaptive changes in dermal coloration for sensing, communication, defense, and reproduction purposes. These capabilities are supported in part by the areal expansion and retraction of pigmented organs known as chromatophores. While it is known that the chromatophores contain a tethered network of pigmented granules, their structure-function properties have not been fully detailed. We describe a method for isolating the nanostructured granules in squid Doryteuthis pealeii chromatophores and demonstrate how their associated pigments can be extracted in acidic solvents. To accomplish this, the chromatophore containing dermal layer is first manually isolated using a superficial dissection, and the pigment granules are removed using sonication, centrifugation, and washing cycles. Pigments confined within the purified granules are then extracted via acidic methanol solutions, leaving nanostructures with smaller diameters that are void of visible color. This extraction procedure produces a 58% yield of soluble pigments isolated from granules. Using this method, the composition of the chromatophore pigments can be determined and used to provide insight into the mechanism of adaptive coloration in cephalopods.

A Method for Extracting Pigments from Squid Doryteuthis pealeii

A protocol for the extraction of pigments from the nanostructured granules in squid Doryteuthis pealeii chromatophores is presented.

Cephalopods can undergo rapid and adaptive changes in dermal coloration for sensing, communication, defense, and reproduction purposes. These capabilities ...

A Simple High Efficiency Protocol for Pancreatic Islet Isolation from Mice

Pancreatic islets, also called the Islets of Langerhans, are a cluster of endocrine cells which produces hormones for glucose regulation and other important biological functions. The islets primarily consist of five types of hormone-secreting cells: &#945; cells secrete glucagon, &#946; cells secrete insulin, &#948; cells secrete somatostatin, &#949; cells secrete ghrelin, and PP cells secrete pancreatic polypeptide. Sixty to 80% of the cells in the islets are &#946; cells, which are the most important cell population to study insulin secretion. Pancreatic islets are a crucial model system to study ex vivo insulin secretion. Acquiring high quality islets is of great importance for diabetes research. Most islet isolation procedures require technically difficult to access site of collagenase injection, harsh and complex digestion procedures, and multiple density gradient purification steps. This paper features a simple high yield mouse islet isolation method with detailed descriptions and realistic demonstrations, showing the following specific steps: 1) injection of collagenase P at the ampulla of Vater, a small area joining the pancreatic duct and the common bile duct, 2) enzymatic digestion and mechanical separation of the exocrine pancreas, and 3) a single gradient purification step. The advantages of this method are the injection of digestive enzyme using the more accessible ampulla of Vater, more complete digestion using combination of enzymatic and mechanical approaches, and a simpler single gradient purification step. This protocol produces approximately 250&#8212;350 islets per mouse; and islets are suitable for various ex vivo studies. Possible caveats of this procedure are potentially damaged islets due to enzymatic digestion and/or prolonged gradient incubation, all of which can be largely avoided by careful ad justification of incubation time.

This islet isolation protocol described a novel route of collagenase injection to digest the exocrine tissue and a simplified gradient procedure to purify the islets from mice. It involves enzymatic digestion, gradient separation/purification, and islet hand-picking. Successful isolation can yield 250&#8211;350 high quality and fully functional islets per mouse.