Wilecki, Martin et al. (2013) International Worm Meeting "The monoamine neurotransmitter serotonin shows evolutionarily divergent effects on feeding behavior in Pristionchus pacificus."

Lightfoot, James W, Sommer, Ralf J, Wilecki, Martin

[International Worm Meeting, 2013]

The ecology and behavior of the diplogastrid nematode Pristionchus pacificus differs substantially from C. elegans. While both nematodes can be cultured on bacteria, P. pacificus is able to exploit alternative food sources. Tooth-like denticles in the mouth enable it to feed on other nematodes and fungi. We are interested in the neurobiological basis behind the predatory vs. bacterial feeding in P. pacificus. Monoamine neurotransmitters regulate several aspects of feeding behavior in C. elegans. Although antibody stainings reveal similar expression patterns in both nematodes, the response to these neurotransmitters in pharmacological experiments differ substantially. Most tested neurotransmitters elicit opposite responses in pharyngeal pumping assays. For example, serotonin is known to stimulate pharyngeal pumping in C. elegans, but it dramatically decreases pharyngeal pumping in P. pacificus. Serotonin also triggers movement of the claw-like dorsal tooth in P. pacificus, which makes it an interesting candidate for more detailed studies of the neurobiology of the predatory feeding. The rate-limiting serotonin synthesis enzyme tryptophan hydroxylase (TPH-1) and the serotonin transporter MOD-5 are highly conserved between P. pacificus and C. elegans. We are using reporter constructs to visualize expression of the underlying genes and use cell ablation experiments to elucidate key neurons involved in regulating the complex feeding behaviors in P. pacificus. We also plan to generate mutants of tph-1 and mod-5 using TALENs for phenotypic analysis of their effects on feeding behaviors.

Bowerman BA et al. (1994) Worm Breeder's Gazette "The Maternal Gene skn-4 and the Specification of Ventral Blastomere Fates in the Early C. elegans Embryo"

Bowerman BA, Shelton CA, Thorpe CJ, Martin PR

[Worm Breeder's Gazette, 1994]

THE MATERNAL GENE SKN-4 AND THE SPECIFICATION OF VENTRAL BLASTOMERE FATES IN THE EARLY C. ELEGANS EMBRYO Bruce Bowerman, Paula R. Martin, Christopher J. Thorpe, and Christopher A. Shelton. The Institute of Molecular Biology, University of Oregon, Eugene, OR 97403.

Zimmer M (2009) Chem Soc Rev "GFP: from jellyfish to the Nobel prize and beyond."

Zimmer M

[Chem Soc Rev, 2009]

On December 10, 2008 Osamu Shimomura, Martin Chalfie and Roger Tsien were awarded the Nobel Prize in Chemistry for "the discovery and development of the green fluorescent protein, GFP". The path taken by this jellyfish protein to become one of the most useful tools in modern science and medicine is described. Osamu Shimomura painstakingly isolated GFP from hundreds of thousands of jellyfish, characterized the chromophore and elucidated the mechanism of Aequorean bioluminescence. Martin Chalfie expressed the protein in E. coli and C. elegans, and Roger Tsien developed a palette of fluorescent proteins that could be used in a myriad of applications.

Hall DH et al. (1994) Worm Breeder's Gazette "Cytology of Degenerin-Induced Cell Death in the PVM Neuron"

Driscoll MA, Chalfie M, Gu GQ, Hall DH, Gong L

[Worm Breeder's Gazette, 1994]

Cytology of degenerin-induced cell death in the PVM neuron David H. Hall, Guoqiang Gu+, Lei Gong#, Monica Driscoll#, and Martin Chalfie+, * Dept. Neuroscience, Albert Einstein College of Medicine, Bronx, N.Y. 10461 + Dept. Biological Sciences, Columbia University, New York, N.Y. 10027 # Dept. Molecular Biology and Biochemistry, Rutgers University, Piscataway, N.J. 08855

Ray C et al. (1990) Worm Breeder's Gazette "CORRECTION Isolation of a C. elegans Cysteine Protease Gene"

McKerrow JH, Ray C

[Worm Breeder's Gazette, 1990]

In the previous issue of the WBG (Vol. 11, #3, page 20) we reported the isolation of a cysteine protease clone from a mixed-stage C. elegans cDNA library. This library was originally obtained from Chris Martin and not from Cynthia Kenyon as was reported in the article. Our apologies for any misunderstanding caused by this oversight.

Okumura, Misako et al. (2015) International Worm Meeting "Serotonin regulates dynamic feeding mode switching inducing predatory kinetics in Pristionchus pacificus."

Sommer, Ralf J., Lightfoot, James W., Okumura, Misako, Wilecki, Martin

[International Worm Meeting, 2015]

Pristionchus pacificus and its relatives are omnivores and are capable of consuming both bacteria and also predating other nematodes including the larvae of Caernorhabditis elegans. To this end Pristionchus species show specific predatory adaptations in the form of teeth-like denticles for lacerating open the cuticle of their prey. Accompanying these teeth structures, the variation in diet induces distinct feeding modes with predation characterised by slowed pharyngeal pumping rates and stimulation of tooth activity, while during bacterial feeding, pumping rates are higher and the tooth remains static. The switch between these distinct feeding modes is rapid, highly dynamic, and dependent on their immediate diet however little is known of the neurological bases regulating the feeding mode switch. Therefore, to elucidate the neurobiological basis underlying the regulation of the predatory feeding behaviour, we conducted pharmacological experiments analysing the effects of several neurotransmitters on pharyngeal pumping and tooth movement rate. Only the addition of serotonin recapitulated the feeding kinetics observed during predatory feeding indicating a previously uncharacterised role for this neurotransmitter. Immunostaining against serotonin revealed an additional serotonergic neuronal pair in the pharynx of P. pacificus compared to C. elegans. These likely correspond to P. pacificus NSM and the interneurons I1. We have subsequently identified the P. pacificus homologues of the serotonin synthesis enzyme (ppa-tph-1) and serotonin transporter (ppa-mod-5) for targeting by CRISPR/Cas9 in order to further investigate the neuronal networks regulating the behavioural switch and for understanding the evolution of these complex behaviours. .

Lightfoot, James et al. (2015) International Worm Meeting "Self-Recognition Prevents Cannibalism in Predatory Nematodes."

Lightfoot, James, Moreno, Eduardo, Susoy, Vladislav, Sommer, Ralf, Wilecki, Martin, Rodelsperger, Christian

[International Worm Meeting, 2015]

Self-recognition described as the capacity to discriminate between identical and foreign tissue is observed abundantly throughout nature and is exploited for a plethora of diverse biological functions. These range from the adaptive immune response in jawed vertebrates to neuronal wiring and dendrite self-avoidance in fruit flies to inducing swarming behaviour in bacteria. However, although self-recognition is observed ubiquitously in nature, relatively little is known about the mechanisms behind this phenomenon and surprisingly, despite the pre-eminence of Caernorhabditis elegans as a model organism, evidence of self-recognition has thus far never been described in nematodes. Our recent investigations explored the feeding dynamics in the predatory nematode Pristionchus pacificus and revealed P. pacificus to be voracious killers of C. elegans. We have subsequently, analysed predatory interactions in the context of self-recognition by investigating predation between P. pacificus and its self-progeny. Predation occurs interspecifically between a wide range of closely related nematode species however never on self-progeny, a mechanism that is conserved amongst other Pristionchus species. Furthermore, the ability to determine self from non-self is highly specific with even closely related strains of P. pacificus perceived as prey, while self-progeny are ignored. The identification of self-progeny is dependent on interactions with surface bound molecules, a process which is maintained despite severe starvation and additionally, not disrupted in a host of cuticle morphology mutants. Finally as even closely related P. pacificus strains predate one another while distinguishing and ignoring self-progeny, we have exploited single nucleotide polymorphisms between two strains and generated recombinant inbred lines (RILs) to isolate the genetic component of self-recognition. Each of the RILs was successfully predated by only a single parental lineage facilitating quantitative trait locus (QTL) mapping resulting in the identification of a putative candidate gene and the underlying molecular mechanism. We thus present the first evidence of self-recognition in nematodes, a phenomenon that enables P. pacificus to avoid cannibalism while also promoting the killing of larvae from potential competing nematodes.

Goto S (1999) Journal of Gerontology "Commentary on "Protein carbonyl accumulation in aging Dauer formation-defective (daf) mutants of Caenorhabditis elegans"."

Goto S

[Journal of Gerontology, 1999]

In recent years, oxidative damage to macromolecules has gained popularity as the basis of the molecular mechanism of aging. Martin proposes oxidative damage to macromolecules as one of the major public mechanisms of aging. Interest in modifications of protein by reactive oxygen species in aging was apparently introduced by Stadtman. Although various types of oxidative modifications can occur in proteins, carbonyl residues believed to be generated by metal catalyzed reaction or otherwise introduced by lysine, arginine and/or proline residues in vivo are often used as a marker of direct or

Hampoelz B et al. (2004) Cell "Heterotrimeric G proteins: new tricks for an old dog."

Knoblich JA, Hampoelz B

[Cell, 2004]

Heterotrimeric G proteins are well known for their function in signal transduction downstream of seven transmembrane receptors. More recently, however, genetic analysis in C. elegans and in Drosophila has revealed a second, essential function of these molecules in positioning the mitotic spindle and attaching microtubules to the cell cortex. Five new publications in Cell (Afshar et al., 2004; Du and Macara, 2004 [this issue of Cell]; Hess et al., 2004), Developmental Cell (Martin-McCaffrey et al., 2004), and Current Biology (Couwenbergs et al., 2004) show that this function is conserved in vertebrates and-like the classical pathway- involves cycling of G proteins between GDP and GTP bound conformations.

Tokuoka SM et al. (2008) Mol Biol Cell "The mood stabilizer valproate inhibits both inositol- and diacylglycerol-signaling pathways in Caenorhabditis elegans."

Tokuoka SM, Saiardi A, Nurrish SJ

[Mol Biol Cell, 2008]

Monitoring Editor: Tom U. Martin The anti-epileptic valproate (VPA) is widely used in the treatment of bipolar disorder, although the mechanism of its action in the disorder is unclear. We show here that VPA inhibits both inositol phosphate and diacylglycerol (DAG) signaling in C.elegans. VPA disrupts two behaviors regulated by the inositol 1,4,5-Tris phosphate (IP3): defecation and ovulation. VPA also inhibits two activities regulated by DAG signaling: acetylcholine (ACh) release and egg-laying. The effects of VPA on DAG signaling are relieved by phorbol ester, a DAG analog, suggesting that VPA acts to inhibit DAG production. VPA reduces levels of DAG and IP1, but PIP2 is slightly increased, suggesting that Phospholipase C mediated hydrolysis of PIP2 to form DAG and IP3 is defective in the presence of VPA.