This work was supported by the National Institutes of HealthGrants DK85035 and DK074797 (I.H).

1. Worm Strains
<ol>
	<li>Obtain C. elegans wildtype Bristol N2 strains from the Caenorhabditis Genetics Center (CGC) (http://www.cbs.umn.edu/cgc) and maintain them on NGM plates seeded with E. coli strain OP507. Note: Transgenic worm strains IQ6011 (Phrg-1::GFP) utilized were generated as previously described11. IQ6011 can be requested from the corresponding author.</li>
</ol>
2. Preparation of Modified C. elegans</em...

<ol>
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Y., Szilagyi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+CeHR+Axenic+Medium+for+Exposure+and+Gene+Expression+Studies.">Use of CeHR Axenic Medium for Exposure and Gene Expression Studies.</a> East Coast Worm Meeting. , (2002).</li><li>Severance, 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=Genome-wide+analysis+reveals+novel+genes+essential+for+heme+homeostasis+in+Caenorhabditis+elegans.">Genome-wide analysis reveals novel genes essential for heme homeostasis in Caenorhabditis elegans.</a> PLoS genetics. 6, e1001044 (2010).</li><li>Rajagopal, A., 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=Haem+homeostasis+is+regulated+by+the+conserved+and+concerted+functions+of+HRG-1+proteins.">Haem homeostasis is regulated by the conserved and concerted functions of HRG-1 proteins.</a> Nature. 453, 1127-1131 (2008).</li><li>Nass, R., Hamza, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+1+Unit+1+9.">Chapter 1 Unit 1 9.</a> The nematode C. elegans as an animal model to explore toxicology in vivo: solid and axenic growth culture conditions and compound exposure parameters. 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In this protocol we present a modified axenic liquid media mCeHR that allows for rapid C. elegans generation with production of a large number of worms. This media shows several advantages as the worms are grown without contaminating E. coli or bacterial byproducts and can be exploited in nutritional and toxicological studies. The use of E. coli or other bacteria in such studies has several drawbacks. For example, the growth of the bacteria can change under various conditions and the bacteria m...

The soil nematode, Caenorhabditis elegans, is a powerful model organism used in numerous studies from genetics to toxicology. As a result of its 1 mm size, rapid generation time of four days, ease of cultivation, and large progeny numbers, these nematodes have been utilized in a number of genetic and pharmacological screens1,2. Researchers take advantage of this worm to identify molecules and pathways conserved in vertebrate systems. These pathways include cell death signals, pathways of aging and metabolism, and the nervous system3-6. Additionally, the transparency of C. elegans allows for the generation of transgenic lines using fluorescent protein reporters, which can be directly visualized to analyze gene expression patterns and protein localization.
In many studies this nematode is cultured on a solid agar-based surface using nematode growth medium (NGM) plates or in liquid cultures seeded with Escherichia coli as a food source7,8. These bacterial food sources can confound biochemical and toxicology studies with interference from bacterial by-products affecting the interpretation of results. In order to avoid these compounding effects, C. elegans can be cultured in an axenic liquid media that is devoid of bacteria as a food source. Using this media, we successfully cultured millions of highly synchronized worms for many standard C. elegans protocols including microarray analysis of differentially regulated genes in C. elegans exposed to different heme concentrations, and production of transgenic worms using gene bombardment. This media is chemically defined and modified from an original recipe formulated by Dr. Eric Clegg9. Using this mCeHR media, we have successfully identified genes involved in heme homeostasis, referred to as heme responsive genes (hrgs)10, which would have not been possible in regular growth conditions which utilize NGM agar plates seeded with E. coli.
In this protocol we describe the procedure for introducing and maintaining C. elegans grown on E. coli to the axenic mCeHR and utilize this method to obtain a large number of worms for producing transgenic C. elegans lines using microparticle bombardment. We also present studies that show the utility of using axenic media for determining the nutritional requirement of C. elegans using heme as an example. These studies show that using mCeHR media allows for rapid growth of a large number of C. elegans for many downstream applications utilized by worm researchers.

<table border="0" cellpadding="0" cellspacing="0" width="754">
	<tbody>
		<tr height="25">
			<td height="25" style="height:25px;width:359px;">MgCl2.6H2O</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">M-2393</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium citrate</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">S-4641</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Potassium citrate.H2O</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">P-1722</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">CuCl2.2H2O</td>
			<td style="width:108px;">Fisher</td>
			<td style="width:121px;">C455-500</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">MnCl2.4H2O</td>
			<td style="width:108px;">Fisher</td>
			<td style="width:121px;">M87-100</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">ZnCl2</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">Z-0152</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">Fe(NH4)2(SO4)2.6H2O</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">F-1018</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">CaCl2.2H2O</td>
			<td style="width:108px;">Fisher</td>
			<td style="width:121px;">C70-500</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Adenosine 5 -monophosphate, sodium salt</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">A-1752</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cytidine 5 -phosphate</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">C-1006</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Guanosine 2 - and3&#160; -monophosphate</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">G-8002</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Uridine 5 -phosphate, disodium salt</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">U-6375</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Thymine&#160;</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">T0376</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">N-Acetylglucosamine</td>
			<td style="width:108px;">Sigma</td>
			<td>A3286</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">DL-Alanine</td>
			<td style="width:108px;">Fisher</td>
			<td>S25648&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">p-Aminobenzoic Acid</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">A-9878</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Biotin</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">B-4639</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Cyanocobalamine (B-12)</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">V-2876</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Folinate (Ca)&#160;</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">F-7878</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Niacin</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">N-0761</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Niacinamide</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">N-3376</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Pantetheine</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">P-2125</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Pantothenate (Ca)</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">P-6292</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Pteroylglutamic Acid (Folic Acid)</td>
			<td style="width:108px;">ACRCS</td>
			<td style="width:121px;">21663-0100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Pyridoxal 5&#39;-phosphate</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">P-3657</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Pyridoxamine.2HCl</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">P-9158</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Pyridoxine.HCl</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">P-6280</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:359px;">Riboflavin 5-PO4(Na)</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">R-7774</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Thiamine.HCl</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">T-1270</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">DL-6,8-Thioctic Acid</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">T-1395</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:359px;">KH2PO4</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">P-5379</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Choline di-acid citrate</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">C-2004</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">myo-Inositol</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">I-5125</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">D-Glucose</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">G-7520</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Lactalbumin enzymatic hydrolysate</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">L-9010</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Brain Heart Infusion</td>
			<td style="width:108px;">BD</td>
			<td style="width:121px;">211065</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:359px;">Hemin chloride</td>
			<td style="width:108px;">Frontier Scientific</td>
			<td style="width:121px;">H651-9</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">HEPES, Na salt</td>
			<td style="width:108px;">Sigma</td>
			<td style="width:121px;">H-3784</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">Cholesterol</td>
			<td style="width:108px;">J.T. Baker</td>
			<td style="width:121px;">F676-05</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MEM Non-Essential Amino Acids</td>
			<td style="width:108px;">Invitrogen</td>
			<td>11140-076</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MEM Amino Acids Solution</td>
			<td style="width:108px;">Invitrogen</td>
			<td>11130-051</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Nalidixic acid sodium salt</td>
			<td style="width:108px;">Sigma</td>
			<td>N4382</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Tetracycline Hydrochloride</td>
			<td style="width:108px;">MP Biomedicals</td>
			<td>2194542</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Biolistic Delivery System</td>
			<td style="width:108px;">BioRad</td>
			<td>165-2257</td>
			<td></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;">Gold particles (Au Powder)&#160;</td>
			<td style="width:108px;">&#160;Ferro Electronic Material Systems</td>
			<td style="width:121px;">6420 2504, JZP01010KM</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:359px;">or</td>
			<td style="width:108px;"></td>
			<td style="width:121px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Gold Particles 1.0 &#956;m</td>
			<td style="width:108px;">BioRad</td>
			<td>&#160;165-2263</td>
			<td></td>
		</tr>
	</tbody>
</table>

culturing caenorhabditis elegans in axenic liquid media and creation of transgenic worms by microparticle bombardment

In this protocol, we present the required materials, and the procedure for making modified&#160;C. elegans&#160;Habituation and Reproduction media (mCeHR). Additionally, the steps for exposing and acclimatizing C. elegans grown on E. coli to axenic liquid media are described. Finally, downstream experiments that utilize axenic C. elegans illustrate the benefits of this procedure. The ability to analyze and determine C. elegans&#160;nutrient requirement was illustrated by growing N2 wild type worms in axenic liquid media with varying heme concentrations. This procedure can be replicated with other nutrients to determine the optimal concentration for worm growth and development or, to determine the toxicological effects of drug treatments. The effects of varied heme concentrations on the growth of wild type worms were determined through qualitative microscopic observation and by quantitating the number of worms that grew in each heme concentration. In addition, the effect of varied nutrient concentrations can be assayed by utilizing worms that express fluorescent sensors that respond to changes in the nutrient of interest. Furthermore, a large number of worms were easily produced for the generation of transgenic C. elegans using microparticle bombardment.

Culturing C. elegans in axenic liquid medium aids in the determination of nutrients that are required by worms, without interference from secondary metabolites produced by E. coli. Wildtype N2 worms acclimatize to mCeHR media within three generations and show growth comparable to worms grown on NGM bacterial plates. Indeed, these worms become gravid within 4&#160;days as compared with 3.5 days for worms grown on OP50 bacteria.
One advantage of using mCeHR was seen in studies ...

Watch this Scientific Journal Video about Culturing Caenorhabditis elegans in Axenic Liquid Media and Creation of Transgenic Worms by Microparticle Bombardment at JoVE.com

Culturing Caenorhabditis elegans in Axenic Liquid Media and Creation of Transgenic Worms by Microparticle Bombardment

C. elegans is usually grown on solid agar plates or in liquid cultures seeded with E. coli. To prevent bacterial byproducts from confounding toxicological and nutritional studies, we utilized an axenic liquid medium, CeHR, to grow and synchronize a large number of worms for a range of downstream applications.

Culturing Caenorhabditis elegans in Axenic Liquid Media and Creation of Transgenic Worms by Microparticle Bombardment

In this protocol, we present the required materials, and the procedure for making modified&#160;C. elegans&#160;Habituation and Reproduction media ...

culturing-caenorhabditis-elegans-axenic-liquid-media-creation

Research

JoVE Journal

Biology

16.8K ビュー.  University of Maryland.  線虫は通常、固形寒天プレート上で増殖させ、または液体培養で大腸菌を接種されている大腸菌 。毒物および栄養研究交絡からの細菌の副生成物を防ぐために、我々はダウンストリームのアプリケーションの範囲のためのワームを大量に成長し、同期させるために、無菌液体培地、CeHRを利用した。 

ビデオ: Culturing Caenorhabditis elegans in Axenic Liquid Media and Creation of Transgenic Worms by Microparticle Bombardment

Measuring Caenorhabditis elegans Life Span on Solid Media

Aging is a degenerative process characterized by a progressive deterioration of cellular components and organelles resulting in mortality. The nematode Caenorhabditis elegans has emerged as a principal model used to study the biology of aging. Because virtually every biological subsystem undergoes functional decline with increasing age, life span is the primary endpoint of interest when considering total rate of aging. In nematodes, life span is typically defined as the number of days an animal remains responsive to external stimuli. Nematodes can be propagated either in liquid media or on solid media in plates, and techniques have been developed for measuring life span under both conditions. Here we present a generalized protocol for measuring life span of nematodes maintained on solid nematode growth media and fed a diet of UV-killed bacteria. These procedures can easily be adapted to assay life span under various common conditions, including a diet consisting of live bacteria, dietary restriction, and RNA interference.

Measuring Caenorhabditis elegans Life Span on Solid Media

In this article we present a general protocol for measuring life span of nematodes maintained on solid media with UV-killed bacterial food.

Aging is a degenerative process characterized by a progressive deterioration of cellular components and organelles resulting in mortality. The nematode ...

Generation of Transgenic C. elegans by Biolistic Transformation

The number of laboratories using the free living nematode C. elegans is rapidly growing. The popularity of this biological model is attributed to a rapid generation time and short life span, easy and inexpensive maintenance, fully sequenced genome, and array of RNAi resources and mutant animals. Additionally, analysis of the C. elegans genome revealed a great similarity between worms and higher vertebrates, which suggests that research in worms could be an important adjunct to studies performed in whole mice or cultured cells. A powerful and important part of worm research is the ability to use transgenic animals to study gene localization and function. Transgenic animals can be created either via microinjection of the worm germline or through the use of biolistic bombardment. Bombardment is a newer technique and is less familiar to a number of labs. Here we describe a simple protocol to generate transgenic worms by biolistic bombardment with gold particles using the Bio-Rad PDS-1000 system. Compared with DNA microinjection into hermaphrodite germline, this protocol has the advantage of not requiring special skills from the operator with regards to identifying worm anatomy or performing microinjection. Further multiple transgenic lines are usually obtained from a single bombardment. Also in contrast to microinjection, biolistic bombardment produces transgenic animals with both extrachromosomal arrays and integrated transgenes. The ability to obtain integrated transgenic lines can avoid the use of mutagenic protocols to integrate foreign DNA. In conclusion, biolistic bombardment can be an attractive method for the generation of transgenic animals, especially for investigators not interested in investing the time and effort needed to become skilled at microinjection.

Generation of Transgenic C. elegans by Biolistic Transformation

Transgenic worms are commonly used in C. elegans research. Described is a simple, yet effective, protocol to introduce transgenes into worms using biolistic bombardment with DNA-coated gold particles. The effort involved and results of bombardment compare favorably with microinjection for the generation of transgenic animals.

The number of laboratories using the free living nematode C. elegans is rapidly growing. The popularity of this biological model is attributed to a rapid ...

Isolation and In vitro Activation of Caenorhabditis elegans Sperm

Males and hermaphrodites are the two naturally found sexual forms in the nematode C. elegans. The amoeboid sperm are produced by both males and hermaphrodites. In the earlier phase of gametogenesis, the germ cells of hermaphrodites differentiate into limited number of sperm - around 300 - and are stored in a small 'bag' called the spermatheca. Later on, hermaphrodites continually produce oocytes1. In contrast, males produce exclusively sperm throughout their adulthood. The males produce so much sperm that it accounts for &gt;50% of the total cells in a typical adult worm2. Therefore, isolating sperm from males is easier than from that of hermaphrodites.
Only a small proportion of males are naturally generated due to spontaneous non-disjunction of X chromosome3. Crossing hermaphrodites with males or more conveniently, the introduction of mutations to give rise to Him (High Incidence of Males) phenotype are some of strategies through which one can enrich the male population3.
Males can be easily distinguished from hermaphrodites by observing the tail morphology4. Hermaphrodite's tail is pointed, whereas male tail is rounded with mating structures.
Cutting the tail releases vast number of spermatids stored inside the male reproductive tract. Dissection is performed under a stereo microscope using 27 gauge needles. Since spermatids are not physically connected with any other cells, hydraulic pressure expels internal contents of male body, including spermatids2.
Males are directly dissected on a small drop of 'Sperm Medium'. Spermatids are sensitive to alteration in the pH. Hence, HEPES, a compound with good buffering capacity is used in sperm media. Glucose and other salts present in sperm media help maintain osmotic pressure to maintain the integrity of sperm.
Post-meiotic differentiation of spermatids into spermatozoa is termed spermiogenesis or sperm activation. Shakes5, and Nelson6 previously showed that round spermatids can be induced to differentiate into spermatozoa by adding various activating compounds including Pronase E. Here we demonstrate in vitro spermiogenesis of C. elegans spermatids using Pronase E.
Successful spermiogenesis is pre-requisite for fertility and hence the mutants defective in spermiogenesis are sterile. Hitherto several mutants have been shown to be defective specifically in spermiogenesis process7. Abnormality found during in vitro activation of novel Spe (Spermatogenesis defective) mutants would help us discover additional players participating in this event.

Isolation and In vitro Activation of Caenorhabditis elegans Sperm

A protocol for isolating and activating spermatids from male C. elegans is described here. Cutting the posterior end of male releases spermatids. The spermatids can be activated by addition of protease.

Males and hermaphrodites are the two naturally found sexual forms in the nematode C. elegans. The amoeboid sperm are produced by both males and ...

Time-lapse Microscopy of Early Embryogenesis in Caenorhabditis elegans

Caenorhabditis elegans has often been used as a model system in studies of early developmental processes. The transparency of the 
embryos, the genetic resources, and the relative ease of transformation are qualities that make C. elegans an excellent model for early embryogenesis. Laser-based 
confocal microscopy and fluorescently labeled tags allow researchers to follow specific cellular structures and proteins in the developing embryo. For example, 
one can follow specific organelles, such as lysosomes or mitochondria, using fluorescently labeled dyes. These dyes can be delivered to the early embryo by means 
of microinjection into the adult gonad. Also, the localization of specific proteins can be followed using fluorescent protein tags. Examples are presented here 
demonstrating the use of a fluorescent lysosomal dye as well as fluorescently tagged histone and ubiquitin proteins. The labeled histone is used to visualize 
the DNA and thus identify the stage of the cell cycle. GFP-tagged ubiquitin reveals the dynamics of ubiquitinated vesicles in the early embryo. Observations 
of labeled lysosomes and GFP:: ubiquitin can be used to determine if there is colocalization between ubiquitinated vesicles and lysosomes. A technique for 
the microinjection of the lysosomal dye is presented. Techniques for generating transgenenic strains are presented elsewhere (1, 2). For imaging, embryos 
are cut out of adult hermaphrodite nematodes and mounted onto 2% agarose pads followed by time-lapse microscopy on a standard laser scanning confocal 
microscope or a spinning disk confocal microscope. This methodology provides for the high resolution visualization of early embryogenesis.

Time-lapse Microscopy of Early Embryogenesis in Caenorhabditis elegans

This article describes a technique for the visualization of the early events of embryogenesis in the nematode Caenorhabditis elegans.

Caenorhabditis elegans has often been used as a model system in studies of early developmental processes.  The transparency of the 
embryos, the genetic ...

Basic Caenorhabditis elegans Methods: Synchronization and Observation

Research into the molecular and developmental biology of the nematode Caenorhabditis elegans was begun in the early seventies by Sydney Brenner and it has since been used extensively as a model organism 1. C. elegans possesses key attributes such as simplicity, transparency and short life cycle that have made it a suitable experimental system for fundamental biological studies for many years 2. Discoveries in this nematode have broad implications because many cellular and molecular processes that control animal development are evolutionary conserved 3.
C. elegans life cycle goes through an embryonic stage and four larval stages before animals reach adulthood. Development can take 2 to 4 days depending on the temperature. In each of the stages several characteristic traits can be observed. The knowledge of its complete cell lineage 4,5 together with the deep annotation of its genome turn this nematode into a great model in fields as diverse as the neurobiology 6, aging 7,8, stem cell biology 9 and germ line biology 10. 
An additional feature that makes C. elegans an attractive model to work with is the possibility of obtaining populations of worms synchronized at a specific stage through a relatively easy protocol. The ease of maintaining and propagating this nematode added to the possibility of synchronization provide a powerful tool to obtain large amounts of worms, which can be used for a wide variety of small or high-throughput experiments such as RNAi screens, microarrays, massive sequencing, immunoblot or in situ hybridization, among others. 
Because of its transparency, C. elegans structures can be distinguished under the microscope using Differential Interference Contrast microscopy, also known as Nomarski microscopy. The use of a fluorescent DNA binder, DAPI (4',6-diamidino-2-phenylindole), for instance, can lead to the specific identification and localization of individual cells, as well as subcellular structures/defects associated to them.

Basic Caenorhabditis elegans Methods: Synchronization and Observation

The easiness of maintaining and propagating the nematode C. elegans make it a nice model organism to work with. The possibility of synchronizing worms allows the work with a significant amount of subjects at the same developmental stage, what facilitates the study of one particular process in many animals.

Research into the molecular and developmental biology of the nematode Caenorhabditis elegans was begun in the early seventies by Sydney Brenner and it has ...

Prostaglandin Extraction and Analysis in Caenorhabditis elegans

Caenorhabditis elegans is emerging as a powerful animal model to study the biology of lipids1-9. Prostaglandins are an important class of eicosanoids, which are lipid signals derived from polyunsaturated fatty acids (PUFAs)10-14. These signalling molecules are difficult to study because of their low abundance and reactive nature. The characteristic feature of prostaglandins is a cyclopentane ring structure located within the fatty acid backbone. In mammals, prostaglandins can be formed through cyclooxygenase enzyme-dependent and -independent pathways10,15. C. elegans synthesizes a wide array of prostaglandins independent of cyclooxygenases6,16,17. A large class of F-series prostaglandins has been identified, but the study of eicosanoids is at an early stage with ample room for new discoveries. Here we describe a procedure for extracting and analyzing prostaglandins and other eicosanoids. Charged lipids are extracted from mass worm cultures using a liquid-liquid extraction technique and analyzed by liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The inclusion of deuterated analogs of prostaglandins, such as PGF2 &alpha;-d4 as an internal standard is recommended for quantitative analysis. Multiple reaction monitoring or MRM can be used to quantify and compare specific prostaglandin types between wild-type and mutant animals. Collision-induced decomposition or MS/MS can be used to obtain information on important structural features. Liquid chromatography mass spectrometry (LC-MS) survey scans of a selected mass range, such as m/z 315-360 can be used to evaluate global changes in prostaglandin levels. We provide examples of all three analyses. These methods will provide researchers with a toolset for discovering novel eicosanoids and delineating their metabolic pathways.

Prostaglandin Extraction and Analysis in Caenorhabditis elegans

In this paper, we describe an optimized procedure for extracting and analyzing prostaglandins and other eicosanoids from C. elegans using LC-MS/MS.

Caenorhabditis elegans is emerging as a powerful animal model to study the biology of lipids1-9. Prostaglandins are an important class of eicosanoids, ...

Culturing of Human Nasal Epithelial Cells at the Air Liquid Interface

In vitro models using human primary epithelial cells are essential in understanding key functions of the respiratory epithelium in the context of microbial infections or inhaled agents. Direct comparisons of cells obtained from diseased populations allow us to characterize different phenotypes and dissect the underlying mechanisms mediating changes in epithelial cell function. Culturing epithelial cells from the human tracheobronchial region has been well documented, but is limited by the availability of human lung tissue or invasiveness associated with obtaining the bronchial brushes biopsies. Nasal epithelial cells are obtained through much less invasive superficial nasal scrape biopsies and subjects can be biopsied multiple times with no significant side effects. Additionally, the nose is the entry point to the respiratory system and therefore one of the first sites to be exposed to any kind of air-borne stressor, such as microbial agents, pollutants, or allergens. 
Briefly, nasal epithelial cells obtained from human volunteers are expanded on coated tissue culture plates, and then transferred onto cell culture inserts. Upon reaching confluency, cells continue to be cultured at the air-liquid interface (ALI), for several weeks, which creates more physiologically relevant conditions. The ALI culture condition uses defined media leading to a differentiated epithelium that exhibits morphological and functional characteristics similar to the human nasal epithelium, with both ciliated and mucus producing cells. Tissue culture inserts with differentiated nasal epithelial cells can be manipulated in a variety of ways depending on the research questions (treatment with pharmacological agents, transduction with lentiviral vectors, exposure to gases, or infection with microbial agents) and analyzed for numerous different endpoints ranging from cellular and molecular pathways, functional changes, morphology, etc. 
In vitro models of differentiated human nasal epithelial cells will enable investigators to address novel and important research questions by using organotypic experimental models that largely mimic the nasal epithelium in vivo.

Nasal epithelial cells, obtained through superficial scrape biopsy of human volunteers, are expanded and transferred onto tissue culture inserts. Upon reaching confluency, cells are grown at air liquid interface, yielding cultures of ciliated and non-ciliated cells. Differentiated nasal epithelial cell cultures provide viable experimental models for studying the respiratory mucosa.

In vitro models using human primary  epithelial cells are essential in understanding key functions of the respiratory  epithelium in the context of ...

A Screenable In Vivo Assay for Mitochondrial Modulators Using Transgenic Bioluminescent Caenorhabditis elegans

The multicellular model organism Caenorhabditis elegans is a small nematode of approximately 1 mm in size in adulthood that is genetically and experimentally tractable. It is economical and easy to culture and dispense in liquid medium which makes it well suited for medium-throughput screening. We have previously validated the use of transgenic luciferase expressing C. elegans strains to provide rapid in vivo assessment of the nematode&#8217;s ATP levels.1-3 Here we present the required materials and procedure to carry out bioassays with the bioluminescent C. elegans strains PE254 or PE255 (or any of their derivative strains). The protocol allows for in vivo detection of sublethal effects of drugs that may identify mitochondrial toxicity, as well as for in vivo detection of potential beneficial drug effects. Representative results are provided for the chemicals paraquat, rotenone, oxaloacetate and for four firefly luciferase inhibitory compounds. The methodology can be scaled up to provide a platform for screening drug libraries for compounds capable of modulating mitochondrial function. Pre-clinical evaluation of drug toxicity is often carried out on immortalized cancerous human cell lines which derive ATP mostly from glycolysis and are often tolerant of mitochondrial toxicants.4,5 In contrast, C. elegans depends on oxidative phosphorylation to sustain development into adulthood, drawing a parallel with humans and providing a unique opportunity for compound evaluation in the physiological context of a whole live multicellular organism.

A Screenable In Vivo Assay for Mitochondrial Modulators Using Transgenic Bioluminescent Caenorhabditis elegans

A protocol is described for in vivo detection of effects of mitochondrial inhibitors in the model organism Caenorhabditis elegans and for identification of potential enhancing compounds. This protocol can be used to screen drug libraries for compounds modulating mitochondrial function.

The multicellular model organism Caenorhabditis elegans is a small nematode of approximately 1 mm in size in adulthood that is genetically and ...

Cultivation of Caenorhabditis elegans in Three Dimensions in the Laboratory

The use of genetic model organisms such as Caenorhabditis elegans has led to seminal discoveries in biology over the last five decades. Most of what we know about C. elegans is limited to laboratory cultivation of the nematodes that may not necessarily reflect the environments they normally inhabit in nature. Cultivation of C. elegans in a 3D habitat that is more similar to the 3D matrix that worms encounter in rotten fruits and vegetative compost in nature could reveal novel phenotypes and behaviors not observed in 2D. In addition, experiments in 3D can address how phenotypes we observe in 2D are relevant for the worm in nature. Here, a new method in which C. elegans grows and reproduces normally in three dimensions is presented. Cultivation of C. elegans in Nematode Growth Tube-3D (NGT-3D) can allow us to measure the reproductive fitness of C. elegans strains or different conditions in a 3D environment. We also present a novel method, termed Nematode Growth Bottle-3D (NGB-3D), to cultivate C. elegans in 3D for microscopic analysis. These methods allow scientists to study C. elegans biology in conditions that are more reflective of the environments they encounter in nature. These can help us to understand the overlying evolutionary relevance of the physiology and behavior of C. elegans we observe in the laboratory.

Cultivation of Caenorhabditis elegans in Three Dimensions in the Laboratory

We present a simple method to construct 3D nematode cultivation systems called NGT-3D and NGB-3D. These can be used to study nematode fitness and behaviors in habitats that are more similar to natural Caenorhabditis elegans habitats than the standard 2D laboratory C. elegans culture plates.

The use of genetic model organisms such as Caenorhabditis elegans has led to seminal discoveries in biology over the last five decades. Most of what we ...

Measurement of Oxygen Consumption Rates in Intact Caenorhabditis elegans

Optimal mitochondrial function is critical for healthy cellular activity, particularly in cells that have high energy demands like those in the nervous system and muscle. Consistent with this, mitochondrial dysfunction has been associated with a myriad of neurodegenerative diseases and aging in general. Caenorhabditis elegans have been a powerful model system for elucidating the many intricacies of mitochondrial function. Mitochondrial respiration is a strong indicator of mitochondrial function and recently developed respirometers offer a state-of-the-art platform to measure respiration in cells. In this protocol, we provide a technique to analyze live, intact C. elegans. This protocol spans a period of ~7 days and includes steps for (1) growing and synchronization of C. elegans, (2) preparation&#160;of compounds to be injected and hydration of probes, (3) drug loading and cartridge equilibration, (4) preparation of worm assay plate and assay run, and (5) post-experiment data analysis.

Measurement of Oxygen Consumption Rates in Intact Caenorhabditis elegans

Mitochondrial respiration is critical for organismal survival; therefore, oxygen consumption rate is an excellent indicator of mitochondrial health. In this protocol, we describe the use of a commercially available respirometer to measure basal and maximal oxygen consumption rates in live, intact, and freely-motile Caenorhabditis elegans.

Optimal mitochondrial function is critical for healthy cellular activity, particularly in cells that have high energy demands like those in the nervous ...