Anin vivomicrofluidic study of bacterial transit inC. elegansnematodes

Abstract

<p>A microfluidic device for studying bacterial transit dynamics in the intestine of <italic>Caenorhabditis elegans</italic>.</p>

An In Vivo Microfluidic Study of Bacterial Load Dynamics and Absorption in the C. elegans Intestine

“…We have used low-magnification (20×) imaging for monitoring the bacterial load of the entire gut of immobilized adult N2 worms. A representative example illustrating our custom-developed image analysis protocol is shown in Figure 2 a [ 49 ]. In this specific case of a worm fed E. coli OP50 RFP (adult N2 worm, trapped for 30 h, see Figure 3 a), the fluorescent image revealed enhanced bacterial load in the terminal bulb (grinder) of the pharynx, which is separated from the intestine by the pharyngeal-intestine valve, and in the posterior region of the intestine (hindgut) ( Figure 2 a, upper image) [ 50 ].…”

“…In a previous work, we characterized in vitro the pH sensitivity of two different E. coli strains, OP50 RFP and HT115 GFP, expressing RFP or GFP fluorescent proteins, respectively. We showed that the RFP marker was not affected in the pH range between 3.7 and 6, while the GFP intensity rapidly decreased even in mildly acidic solutions (pH 6) [ 49 ]. Here we studied the fate of these two E. coli strains in vivo.…”

“…Here, we focus on single representative worms. Results obtained on larger populations showing bacterial distribution patterns in wild-type worms and eat-2 mutants were presented in our previous paper [ 49 ]. Figure 4 a shows a time-lapse sequence of high-resolution images (50×) of the hindgut of an immobilized YA N2 worm fed E. coli HT115 GFP.…”

Surface acoustic wave microfluidics for repetitive and reversible temporary immobilization of C. elegans

“…22 These techniques are useful when focusing on the high-resolution imaging aspect of long-term C. elegans studies. However, due to the constrained geometry that could potentially induce mechanical stress in animals, 21 these groups either did not conduct concurrent behavior studies 20,22 or performed them on separate groups of non-immobilized animals. 21 Alternatively, active immobilization methods introduce an external force to temporarily cease animal movements.…”

“…However, due to the constrained geometry that could potentially induce mechanical stress in animals, 21 these groups either did not conduct concurrent behavior studies 20,22 or performed them on separate groups of non-immobilized animals. 21 Alternatively, active immobilization methods introduce an external force to temporarily cease animal movements. These methods allow for larger channel geometries where animals can swim freely when not actively immobilized.…”