Abstract

The pharynx is a neuromuscular pump at the anterior end of the alimentary tract. It is made up of 20 muscle cells, 20 neurons, and 20 other cells. Pharyngeal activity correlates with food intake. The proper feeding rate, as well as the precise timing of pharyngeal movements, is required for efficient feeding and likely for survival in nature. For most purposes, pharyngeal behavioral analysis requires no more than a routine stereomicroscope and a pair of eyes, but accuracy can be increased by video recording followed by off-line analysis in slow motion. Like other C. elegans behaviors, pharyngeal behavior is sensitive to both the immediate environmental conditions as well as to the history of such conditions.

Highlights

  • The movement of bacteria from outside the worm to the intestine is accomplished by two pharyngeal movements: pumps and isthmus peristalses

  • Pumps consist of coordinated contraction-relaxation cycles of the radially-oriented muscles of the corpus, anterior isthmus, and terminal bulb (Figure 1, 2A and Movie 1)

  • Peristaltic motion transports bacteria trapped in the anterior isthmus to the grinder in the terminal bulb

Read more

Summary

Pumping

Because pumping rate can vary from minute-to-minute or even second-to-second (Hobson et al, 2006), it is sometimes desirable to measure ppm of the same worm several times This is useful when the worm studied is a precious one (for example, an animal on which a laser-ablation operation had been performed); in such a case, pumping rate can be counted for 10-20 seconds every minute for 10 minutes and the median or mean is used. A simple stereomicroscope is adequate for counting pumps based on grinder movements, a compound microscope equipped with DIC optics is necessary for observing movements in the corpus and isthmus or for measuring the speed of contraction or relaxation. For example when measuring the speed of pharyngeal relaxation in subparts of the pharynx, a camera that is specialized for high speed recording (for example, Andor iXon camera) capable of frame rates on the order of 1000 frames per second is required (Fang-Yen et al, 2009)

Isthmus peristalsis
Cessation of feeding
Preparation of worms and test plates
Inducing satiety quiescence using a fasting and refeeding assay
Inducing satiety quiescence using high-quality bacteria
Findings
Procedures
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call