Category Archives: Caenorhabditis elegans

Journal Club: Connecting a Connectome to Behavior

0yks_X4B3uHScKQYMpmLDzl72eJkfbmt4t8yenImKBVaiQDB_Rd1H6kmuBWtceBJAn obvious goal of connectomics is to use it is a tool for better understanding complex network function. As new data are becoming available it is  not entirely clear what the best methods are for extracting useful information out of connectivity matrices. Part of the problem lies in the fact that while a wiring diagram is necessary for understanding nervous system function, it is hardly sufficient. The painful reality is that in complex systems like networks of neurons, small details of neuron and synapse function can dramatically alter system behavior. A recent Plos Computational Biology paper by Eduardo Izquierdo and Randall Beer at Indiana University makes what I think is a useful contribution to the problem by Continue reading

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Räuberischer Schlund

predatorypressreleaseMuch to my amusement, I found out that the local newspaper, the Schwäbisches Tagblatt, picked up on our press release and published a nice little story. The title “Räubuerischer Schlund” translates to “Predatory Mouth”, referring to  the toothy mouth Pristionchus pacificus uses to puncture its prey. Pretty cool! The image on this post is the same one used in the press release, and shows P. pacificus chomping down on C. elegans. Click HERE for a link to the article. It’s in German, so if you need to you can have a look at it in google translate.

Pristionchus pacificus predatory feeding video

One of the things that interests me about the nematode Pristionchus pacificus is that it is capable of taking advantage of many different food sources. Like it’s cousin and well known model organism Caenorhabditis elegans, this nematode can be raised on agar plates seeded with bacteria. Pristionchus can additionally feed on other sources, including other nematodes! These predatory feeding behaviors are quite distinct from bacterial feeding. For instance, Pristionchus has tooth-like denticles in its mouth opening that are highly active during predatory but not bacterial feeding. This increase in the complexity of the P. pacificus
behavioral palette is most interesting when you consider that the nervous systems are composed of a nearly identical set of neurons. So how do you teach an old nervous system to do new tricks? This is one of my primary motivations for comparing networks of synaptic connectivity between these two species.

Neural Circuit Meeting at CSHL, and a trip to Albert einstein to boot.

During the last week of March, I made a trip to the good ol’ U.S.A. to attend the Neuronal Circuits meeting at Cold Spring Harbor Laboratory out on Long Island. There, I presented a talk entitled “Comparative Graph Theoretical Analysis of Networks of Identified Neurons.” During the talk, I summarized the Pristionchus connectivity project as well as introduced some of the graph theory methods I’ve been working on for asking questions of connectivity networks. For me, the meeting was outstanding. All of the talks were well presented and of a very high standard… you can count on your mind being blown at least a couple of times a day at these meetings! CSHL is an excellent (though expensive) venue for meetings, and the  meeting itself was structured to allow plenty of time to talk with people. There weren’t so many worm people there, but Scott Emmons presented his connectivity dataset for the male in C. elegans, Julie Cho from Paul Sternberg’s lab presented a nice talk on her work dealing with lethargic (“sleep”) and a couple of awesome grad students from Mark Alkema’s lab had posters (Christopher Clark and Jennifer Pirri). They look at locomotion circuits, including examining how C. elegans avoids nematode trapping fungi. I’ve always been a fan of Arthrobotrys! Prior to the meeting, I went out to the Albert Einstein College of Medicine in the Bronx to visit the labs of David Hall and Scott Emmons. Their work on the male tail is impressive, available already online (www.wormatlas.org) and should be published this year. I always like visiting David’s lab because it is kind of an electron microscopy museum, containing many of the early and important electron micrographs for C. elegans. This time around, there was a new addition: the original wooden models constructed by, I think, John White in order to investigate vulva development! Apparently, Dave saved them from being discarded. Dave is also an Avid birder and an active conservationist, so in between lab visits I had a chance to tag along to some of his birding sites. Truly an action packed trip! To see some additional photos, look at my Flickr page HERE.