K Omata et al. (1999) International C. elegans Meeting "Characterization of the neural circuit of C. elegans: model analysis of the touch response"

F Yonezawa, K Omata, K Kawamura

[International C. elegans Meeting, 1999]

In order to characterize the neural circuit of C. elagans, we construct a simple model by making use of the data table completed recently by Oshio et al . [1]. We assume that the signal of a neuron is calculated by the product of the signals from the neighboring neurons, and we investigate the touch sensitivity to continuous stimuli described by sinusoidal functions as defined in the rage from 0.0 to 1.0. We calculate the responses of the motor neurons by changing the frequencies of the stimuli. In our calculations, we change only the frequency w PLM for the input signal to the sensory neuron PLM, while the frequency for the other sensory neurons ALM, AVM and PVM is fixed to be a same value w 0 . We show that the output signals from the motor neurons A and B oscillate in time. We measure the minima of the oscillation for each w PLM value. The plot of the minima versus w PLM shows different hehaviors for the case of the neuron A and B. As for the signals from the neuron A, the values of the minima are widely distributed between 0.0 and 1.0 for all w PLM . As for the signals from the neuron B, on the other hand, the features are different for different w PLM values. (a) In the high frequency region of w PLM / w 0 0.4, the oscillation is simple harmonic and there exists only one minimum value (I min = 0.0). (b) As w PLM / w 0 is decreased, another minimum appears at a certain frequency, and the bifurcation takes place discontinuously. This behavior is different from usual continuous bifurcation observed in nonlinear systems. After a few discontinuous branching occur, signals with five periods can be seen in the intermediate frequency region of 0.3 w PLM / w 0 w PLM / w 0 [1] K. Oshio et al. ; C. elegans synaptic connectivity data'', Technical Report, CCEP, Keio Future No.1 (1998).

G Lochnit et al. (2004) European Worm Meeting "FIRST IDENTIFICATION OF A PHOSPHORYLCHOLINE-SUBSTITUTED PROTEIN FROM CAENORHABDITIS ELEGANS ISOLATION AND CHARACTERIZATION OF THE ASPARTYL PROTEASE ASP-6."

R Geyer, G Lochnit, B Henkel, J Grabitzki

[European Worm Meeting, 2004]

Caenorhabditis elegans has been found to be a good model system for parasitic nematodes, drug screening and developmental studies. Structural analyses have revealed nematode specific glycosphingolipid structures of the arthro-series, carrying, in part, phosphorylcholine (PC) substituents. PC is a widespread antigenic epitope of pathogens like parasitic nematodes and has also been detected on N-glycans of this model organism (1, 2). The PC modification seems to play an important role in nematodes development, fertility and survival within the host. With the exception of ES-62 from Achanthocheilonema viteae no protein carrying this epitope has been yet identified and further characterized (3). In the axenic medium of C. elegans culture we detected a single protein with an apparent molecular mass of 40 kDa which reacted with the PC-specific antibody TEPC-15. The protein was purified by anion-exchange chromatography and 2D-gel electrophoresis. After in-gel digestion with trypsin, the protein was identified by MALDI-TOF-MS peptide finger print and nanoLC-ESI-MS/MS microsequencing as the aspartyl protease ASP-6. RNAi experiments confirmed is assignment. Lectin analysis of the purified ASP-6 protein revealed the presence of the GlcNAc-residues by binding of WGA, whereas Con A showed no binding, indicating the absence of terminal mannosyl residues. Treatment of the protein with PNGase A and PNGase F abolished the binding of WGA, but not that of TEPC-15. This might be an indication for a PC-epitope distinct from those described so far. References: 1. Lochnit, G. et al. (2000) Biol. Chem. 381: 839-47 2. Houston, K., et al. (2002) Mol. Biochem. Parasitol. 123: 55-66 3. Harnett, W., et al. (2003) Curr.Protein Pept. Sci. 4: 59-71

J Grabitzki et al. (2004) European Worm Meeting "THE PCOME OF CAENORHABDITIS ELEGANS IDENTIFICATION OF PHOSPHORYLCHOLINE-SUBSTITUTED PROTEINS AND COMPARISON OF DEVELOPMENTAL CHANGES IN THE EXPRESSION OF THIS EPITOPE"

R Geyer, G Lochnit, J Grabitzki

[European Worm Meeting, 2004]

Caenorhabditis elegans has been found to be good model system for parasitic nematodes, drug screening and developmental studies. Like the respective parasitic worms, C. elegans expresses glycosphingolipids and glycoproteins, carrying, in part, phosphorylcholine (PC) substitutents, which might play important roles in nematode development, fertility and, at least in the case of parasites, the survival within the host (1). With the exception of a major secretory/ excretory product from Achanthocheilonema viteae (ES-62) (2) and the aspartyl-protease ASP-6 (3), no other proteins carrying this epitope has been identified and studied in detail yet. For C. elegans two N-linked PC-epitopes have been reported so far: (I) a pentamannosyl-core structure carrying three PC-residues (4) and (II) a trimannosyl-core species elongated by a N-acetylglucosamine substituted at C-6 with PC (5). Furthermore, in Dauer larvae of C. elegans there was evidence for the presence of glycans with the composition PC1Hex3HexNAc3 to PC2dHex2Hex4HexNAc7 (6). Here we present the 2D-electrophoretic separation of C. elegans proteins, the comparison of the PC-substitution pattern in distinct developmental stages and the mass spectrometric identification of PC-modified proteins. References: 1.Lochnit, G., Dennis, R. D., and Geyer, R. (2000) Biol Chem 381, 839-847 2.Harnett, W., Harnett, M. M., and Byron, O. (2003) Curr Protein Pept Sci 4, 59-71 3.Lochnit, G., Grabitzki, J., Henkel, B., and Geyer, R. (2003) Biochemical Journal submitted 4.Cipollo, J. F., Costello, C. E., and Hirschberg, C. B. (2002) J Biol Chem 277, 49143-49157 5.Haslam, S. M., Gems, D., Morris, H. R., and Dell, A. (2002) Biochem. Soc. Symp. 69, 117-134 6.Cipollo, J. F., Awad, A., Costello, C. E., Robbins, P. W., and Hirschberg, C. B. (2004) Proc Natl Acad Sci U S A 101, 3404-3408

Julia Grabitzki et al. (2006) European Worm Meeting "Phosphorylcholine-Modified Proteins of Caenorhabditis elegans are Specific to Developmental Stages"

Michael Ahrend, Gunter Lochnit, Julia Grabitzki, Rudolf Geyer

[European Worm Meeting, 2006]

Julia Grabitzki, Michael Ahrend, Rudolf Geyer and Gunter Lochnit. The free-living nematode Caenorhabditis elegans has been found to be an excellent model system for developmental studies [1] investigating parasitic nematodes [2] and drug screening [3]. Structural analyses of glycoconjugates derived from this organism revealed the presence of nematode specific glycosphingolipids of the arthro-series, carrying, in part, phosphorylcholine (PC) substituents [2]. PC, a small haptenic molecule, is found in a wide variety of prokaryotic organisms, i. e. bacteria, and in eukaryotic parasites such as nematodes. There is evidence that PC-substituted proteins glycolipids are assumed to be responsible for a variety of immunological effects including invasion mechanisms and long-term persistence of parasites within the host [4]. In contrast to PC-modified glycosphingolipids [5], only a limited number of PC-carrying (glyco)proteins were identified so far [6-9]. We have analysed the expression of PC-modified proteins of C. elegans during developmental stages using two dimensional SDS-Page separation, 2D-Western-blot and MALDI-TOF mass spectrometry. The pattern of PC-modified proteins was found to be stage specific. The PC-modification on proteins was most abundant in the egg and dauer larvae-stages followed by the adult-stage and L4. Only small amounts of the PC-substitution were found in L3 and L2. In L1 we couldnt detect any PC-Modification. The prediction of the cellular localisation of the identified proteins revealed a predominant cytosolic and mitochondrial occurrence of the PC- modification. Most of the identified proteins are involved in metabolism or in protein synthesis.. 1.. Brenner, S., Genetics, 1974. 77(1): p. 71-94.. 2.. Lochnit, G., R.D. Dennis, and R. Geyer, Biol Chem, 2000. 381(9-10): p. 839-47.. 3.. Lochnit, G., R. Bongaarts, and R. Geyer, Int J Parasitol, 2005. 35(8): p. 911-23.. 4.. Harnett, W. and M.M. Harnett, Mod. Asp. Immunobiol., 2000. 1(2): p. 40-42.. 5.. Friedl, C.H., G. Lochnit, R. Geyer, M. Karas, and U. Bahr, Anal Biochem, 2000. 284(2): p. 279-87.. 6.. Haslam, S.M., H.R. Morris, and A. Dell, Trends Parasitol, 2001. 17(5): p. 231-5.. 7.. Cipollo, J.F., C.E. Costello, and C.B. Hirschberg, J Biol Chem, 2002. 277(51): p. 49143-57.. 8.. Cipollo, J.F., A.M. Awad, C.E. Costello, and C.B. Hirschberg, J Biol Chem, 2005. 280(28): p. 26063-72.

Mantilla Galindo, Alejandra et al. (2021) International Worm Meeting "Evaluacion del efecto del extracto etanolico de Witheringia coccoloboides sobre agregados de alpha- sinucleína en la cepa NL5901 de Caenorhabditis elegans"

Mantilla Galindo, Alejandra, Sanchez Mora, Ruth Melida, Gonzalez Devia, Johanna Lizeth, Hidalgo Pulido, Karen Lorena

[International Worm Meeting, 2021]

Neurodegenerative diseases (ND) are a public health problem, cause permanent disability and a high cost in health systems. People affected with Parkinson disease have protein deposits of alpha-synuclein (alpha-syn) in brain cells. The use of biological models such as Caenorhabditis elegans (C. elegans) can answer questions that arise day by day for the development of new therapeutic targets for ND. The transgenic strain NL5901 of C. elegans is characterized to have alpha-syn aggregates labeled with yellow fluorescent protein (YFP), which allows to evaluate compounds effect on the physiological characteristics and / or the reduction of protein aggregates alpha-syn in this model. On the other hand, Witheringia coccoloboides (W. coccoloboides) has been described as a promising plant in the palliative treatment of ND and therefore of interest in ethnopharmacology due to its possible neuroprotective action. Therefore, the main objective of this study was to evaluate the effect of the ethanolic extract of leaves of W. coccoloboides on the physiological characteristics and protein aggregates of alpha-syn in the mutant strain NL5901 of C. elegans. The results of the present work show that the ethanolic extract of leaves of W. coccoloboides has a reducing effect of protein aggregates alpha-syn, improving the physiological characteristics of reproduction and motility, as well as, decreasing the levels of Reactive Oxygen Species (ROS) in strain NL5901 of C. elegans. Therefore, it is possible to suggest that the ethanolic extract of leaves of W. coccoloboides has a protective effect on strain NL5901 of C. elegans, probably attributed to the presence of sterols and / or terpenes, flavonoids and alkaloids, which in turn, it is generate a recovery of muscular activity in the egg lay and locomotion, probably all linked, to synergistic interaction of the phytocompounds present in the ethanolic extract of leaves of W. Coccoloboides. Keywords: Witheringia coccoloboides, alpha-synuclein, Parkinson disease, Caenorhabditis elegans

Dustin L Updike et al. (2005) International Worm Meeting "The TIP60/SWR1 Chromatin Remodeling Complex Functions with the Selector Gene PHA-4 to Endow Cells with Pharyngeal Competence"

Dustin L Updike, Susan E Mango

[International Worm Meeting, 2005]

A critical question in developmental biology is how complex programs of gene expression are orchestrated by a class of regulators known as selector genes. Selector genes code for transcription factors that autonomously govern the fates of groups of cells related to each other by virtue of their cell type, position or affiliation to an organ (1). For example, the FoxA transcription factor PHA-4 dictates the identity of cells within the C. elegans pharynx. Embryos that lack pha-4 fail to generate pharyngeal cells, and these cells acquire an alternative ectodermal fate instead (2,3). PHA-4 functions in combination with additional transcription factors to modulate genes at distinct stages and in different cell types during pharyngeal development (4,5). Here we explore the role of PHA-4 during transcriptional regulation. We identified components of the TIP60/SWR1 complex in a screen for loci that interact genetically with PHA-4. The predicted histone acetyltransferase mys-1 and chromatin remodeling factor ssl-1 each enhanced partial loss of pha-4 activity. In other organisms, the SSL-1 complex exchanges nucleosomes with histone H2A for those containing the variant H2Az (6). Nucleosomes containing H2Az appear less stable than those carrying H2A, which may facilitate the subsequent removal of nucleosomes for activation or repression (7). Consistent with this idea, C. elegans H2Az enhances the pharyngeal phenotype of pha-4 alleles, similar to ssl-1. Furthermore, we observe H2Az associated with PHA-4 target promoters in nascent pharyngeal cells. We propose that the MYS-1/SSL-1 chromatin remodeling complex functions with PHA-4 to endow cells with pharyngeal competence by restructuring the chromatin environment around PHA-4 target genes. Chromatin restructuring may render these promoters susceptible to binding by additional transcription factors that modulate pharyngeal gene expression in conjunction with PHA-4.1) R. S. Mann, S. B. Carroll, Curr. Opin. Genet. Dev. 12, 592 (2002). 2) S. E. Mango, E. J. Lambie, J. Kimble, Development 120, 3019 (1994). 3) M. A. Horner et al., Genes Dev. 12, 1947 (1998). 4) J. Gaudet, S. Muttumu, M. Horner, S. E. Mango, PLoS Biol. 2, e352 (2004). 5) W. Ao, J. Gaudet, W. J. Kent, S. Muttumu, S. E. Mango, Science 305, 1743 (2004). 6) G. Mizuguchi, X. Shen, J. Landry, W. H. Wu, S. Sen, C. Wu, Science 303, 343 (2004). 7) D. W. Abbott, V. S. Ivanova, X Wang, W. M. Bonner, J. Ausio, J. Biol. Chem. 276, 945 (2001).

Takao Inoue et al. (2002) West Coast Worm Meeting "lin-17, lin-18 and patterning of the P7.p lineage"

Rashmi Deshpande, Paul W Sternberg, Russell Hill, Takao Inoue

[West Coast Worm Meeting, 2002]

We are interested in patterning of the 2 (secondary) vulval lineages P5.p and P7.p. In the wild-type, P5.p and P7.p produce stereotyped ABCD and DCBA patterns respectively. In lin-17 and lin-18 mutants, the polarity of the P7.p lineage becomes altered. We examined the P7.p lineage in lin-17 (encoding Frizzled Wnt receptor), lin-18 (encoding RYK receptor tyrosine kinase-related protein; W. Katz and P.W.S.), and double mutant using POP-1 (TCF/LEF) antibody staining and cell fate markers ceh-2::yfp and cdh-3::cfp.

Shawn Lockery (2003) International Worm Meeting "Theoretical analysis of locomotory switching in C. elegans"

Shawn Lockery

[International Worm Meeting, 2003]

Locomotory state in C. elegans is thought to be regulated by a network of command interneurons in two functional pools: the forward command neurons AVB and PVC, and the reverse command neurons AVA and AVD. It has been proposed that the circuit functions as a bistable switch in which only one pool is on at a time. This model is consistent with the observation that presumptive depolarization of both pools (by activated glutamate-receptor knock-in) decreases dwell time in the forward state, whereas presumptive hyperpolarization (by reducing tonic glutamate transmission) increases dwell time in the forward state. However, the bistable switch model does not easily account for the paradoxical observation that dwell time in the forward state is decreased whether one kills forward command neurons (AVB) or reverse command neurons (AVA).Here I propose an alternative model based on four assumptions. (1) Neurons switch stochastically between on and off states with a probability that increases with net synaptic input. (2) Forward command neurons act as a single unit, as do reverse command neurons. (3) Units in the model can adopt four activation states: (i) both off, (ii) forward on, reverse off, (iii) reverse on, forward off, (iv) both off. (4) The four activation states correspond, respectively, to the four main locomotory states: stop, forward, reverse, and omega turn. Unit activity is governed by three synaptic parameters: h, net input from sensory systems; w, the strength of the connections from the unit to its partner; and z, the strength of connections among neurons in the same pool. A key feature of the model is that the rate constants for transitions between its states can be expressed terms of the underlying neuronal parameters h, w, and z. This feature, together with the correspondence between activation states in the model and locomotory states in the animal, allows one to predict synaptic strengths in the command network from the rate constants for locomotory state transitions in the animal.Using a curve fitting routine, I adjusted h, w, and z to fit the rate constants for switching between locomotory states measured in real animals. I tested the model by increasing or decreasing h to mimic, respectively, depolarization and hyperpolarization of command neurons. I found that dwell time in the forward state was modulated as in real worms. In a second test, I decreased the values of h, w, and z in the forward unit by 50% to mimic ablation of the forward neuron AVB and found, as expected, that forward dwell time was decreased. Remarkably, mimicking ablation of the reverse neuron AVA also decreased forward dwell time. The new model therefore provides a successful alternative to the bistable switch hypothesis. NIH MH51383.

Maureen M Barr (2001) International C. elegans Meeting "Lov neurotransmission"

Maureen M Barr

[International C. elegans Meeting, 2001]

The nervous system of the adult C. elegans male possesses 381 neurons to the hermaphrodite's 302. These additional sex-specific neurons are required for male mating behaviors, namely, response to hermaphrodite contact, backing, turning, location of vulva (Lov), spicule insertion, and sperm transfer. We are specifically studying Lov behavior at the cellular, genetic, and molecular levels. The HOA and HOB hook neurons are required for Lov behavior (1) and the putative sensory receptor lov-1 is expressed in HOB (2). How does signaling initiated by the LOV-1 receptor culminate in Lov behavior? We are interested in identifying the neurotransmitters and neuropeptides used by the HOA and HOB mechano- and chemosensory neurons, respectively (3). Anne Hart and Arif Nathoo have identified 21 putative n europeptide like protein ( nlp ) genes in C. elegans and made transcriptional GFP fusions (4) which we have screened for expression in the adult male tail. An nlp-8::gfp transcriptional fusion is expressed uniformly throughout the HOB neuron. Expression is also observed in other non-sex, non-stage specific cells. We have constructed a full length nlp-8::gfp translational fusion and observed expression only in HOB, suggesting nlp-8 may be a Lov neuropeptide. We are exploring the role of nlp-8 in Lov behavior using genetic and molecular approaches. Liu, K. S. and P. W. Sternberg. 1995. Neuron 14:79-89. Barr, M. M. and P. W. Sternberg. 1999. Nature 401: 386-389. Sulston, J. E. et al. 1980. Developmental Biology 78:542-576. Nathoo, A., R. Moeller, and A. Hart. 1999. International Worm Meeting abstract 621.

Kulas, Jana et al. (2009) International Worm Meeting "Cytochrome P450-dependent metabolism of poly-unsaturated fatty acids (PUFA) in the nematode Caenorhabditis elegans."

Schmidt, Cosima, Kulas, Jana, Steinberg, Christian, Kosel, Mandy, Rothe, Michael, Menzel, Ralph

[International Worm Meeting, 2009]

We tested here the hypothesis that some of Caenorhabditis elegans cytochrome P450 (CYP) forms may be involved in the metabolism of polyunsaturated fatty acids (PUFA), especially eicosapentaenoic acid (EPA), the predominant PUFA of this nematode. Microsomes isolated from adult worms contained spectrally active CYP proteins and showed NADPH-CYP reductase (CPR) activities. They metabolized EPA and, with lower activity, also arachidonic acid (AA) to specific sets of regioisomeric epoxy- and w-/(w-1)-hydroxy-derivatives. 17(R),18(S)-epoxyeicosatetraenoic acid was produced as the main EPA metabolite with an enantiomeric purity of 72 %. The epoxygenase and hydroxylase reactions were NADPH-dependent, required the functional expression of the CPR-encoding emb-8 gene, and were inhibited by 17-ODYA and PPOH, two compounds known to inactivate mammalian AA-metabolizing CYP isoforms. Multiple followed by single RNAi gene silencing experiments identified CYP-29A3 and CYP-33E2 as the major isoforms contributing to EPA metabolism in C. elegans. Liquid chromatography/ mass spectrometry revealed that regioisomeric epoxy- and hydroxy-derivatives of EPA and AA are endogenous constituents of C. elegans. The endogenous EPA metabolite levels were increased by treating the worms with fenofibrate, which also induced the microsomal epoxygenase and hydroxylase activities. Heterologous expression of cyp-29A3 and cyp-33E2 in SF9 insect cells is in progress. These results demonstrate for the first time that C. elegans shares with mammals the capacity to produce CYP-dependent eicosanoids and may thus facilitate future studies on the mechanisms of action of this important class of signaling molecules.