Olivares, E.O. et al. (2017) International Worm Meeting "Connectome analysis shows the feasibility of ventral cord central pattern generators driving locomotion in C. elegans."

Izquierdo, E.J., Olivares, E.O., Beer, R.D.

[International Worm Meeting, 2017]

Since nearly its entire behavioral repertoire is expressed through movement, understanding the neural basis of locomotion is especially critical as a foundation upon which analyses of all other behaviors must build. C. elegans locomotes in an undulatory fashion, generating thrust by propagating dorso-ventral bends along its body. How the rhythmic patterns are generated is not yet understood. While central pattern generators are involved in animal locomotion from leech to humans, their presence in C. elegans has been questioned, mainly because there has been no evident neural motif that supports intrinsic oscillations. With a fully reconstructed connectome, the question of whether it is possible to have a CPG in the ventral cord of C. elegans can be answered through computational models. We modeled the ventral cord circuit based on the most up-to-date connectome data and segmentation analysis. In order to explore the possibility of intrinsic oscillations, we used an evolutionary algorithm to determine the unknown physiological parameters of each neuron so as to match the features of the neural traces of the worm during forward and backward locomotion. We performed 1000 evolutionary runs and consistently found circuits that produced oscillations matching the main characteristic observed in experimental recordings. While most of the successful solutions shared common mechanisms, the polarity and weight of the synapses were not always the same. Each of the different solutions represents a configuration capable of generating locomotion-like intrinsic oscillations. This insight can be used to propose experiments on the living organism that test the hypotheses generated by the different solutions. Analysis of successful networks suggested roles for the known motorneurons that aligned well with experimental evidence. It also suggested a role for the AS-class, which has been almost entirely ignored in the study of C. elegans locomotion. In the majority of evolved circuits, motorneuron AS was fundamental to both the generation of oscillations and to the dorsoventral antiphase coordination. We also found that in most of the solutions the AS-class was bistable, while the B- and A-class were not. This is different from what previous models of locomotion had proposed thus far. In addition to providing an existence proof for the possibility of intrinsic oscillations in the ventral cord, we suggest a series of testable hypotheses about its operation. More generally, we show the feasibility and fruitfulness of a methodology to study behavior from a connectome, while neurophysiological properties are still missing.

Shin N et al. (2020) Sci Rep "Micelle-stabilized Olfactory Receptors for a Bioelectronic Nose Detecting Butter Flavors in Real Fermented Alcoholic Beverages."

Park TH, Lee SH, Shin N, Pham Ba VA, Hong S

[Sci Rep, 2020]

A bioelectronic nose device based on micelle-stabilized olfactory receptors is developed for the selective discrimination of a butter flavor substance in commercial fermented alcoholic beverages. In this work, we have successfully overexpressed ODR-10, a type of olfactory receptor, from Caenorhabditis elegans using a bacterial expression system at a low cost and high productivity. The highly-purified ODR-10 was stabilized in micelle structures, and it was immobilized on a carbon nanotube field-effect transistor to build a bioelectronic nose for the detection of diacetyl, a butter flavor substance, via the specific interaction between diacetyl and ODR-10. The bioelectronic nose device can sensitively detect diacetyl down to 10 fM, and selectively discriminate it from other substances. In addition, this sensor could directly evaluate diacetyl levels in a variety of real fermented alcoholic beverages such as beer, wine, and makgeolli (fermented Korean wine), while the sensor did not respond to soju (Korean style liquor without diacetyl). In this respect, our sensor should be a powerful tool for versatile food industrial applications such as the quality control of alcoholic beverages and foods.

Palmioli A et al. (2022) ACS Chem Neurosci "Alzheimer's Disease Prevention through Natural Compounds: Cell-Free , In Vitro, and In Vivo Dissection of Hop ( Humulus lupulus L.) Multitarget Activity"

Zoia CP, Bazzini C, Palmioli A, Colombo L, Inserra M, Ferrarese C, Diomede L, Sala G, Bruzzone C, De Luigi A, Mazzoni V, De Noni I, Airoldi C, Salmona M

[ACS Chem Neurosci, 2022]

The relevant social and economic costs associated with aging and neurodegenerative diseases, particularly Alzheimer's disease (AD), entail considerable efforts to develop effective preventive and therapeutic strategies. The search for natural compounds, whose intake through diet can help prevent the main biochemical mechanisms responsible for AD onset, led us to screen hops, one of the main ingredients of beer. To explore the chemical variability of hops, we characterized four hop varieties, i.e., Cascade, Saaz, Tettnang, and Summit. We investigated the potential multitarget hop activity, in particular its ability to hinder Aβ1-42 peptide aggregation and cytotoxicity, its antioxidant properties, and its ability to enhance autophagy, promoting the clearance of misfolded and aggregated proteins in a human neuroblastoma SH-SY5Y cell line. Moreover, we provided evidence of in vivo hop efficacy using the transgenic CL2006 Caenorhabditis elegans strain expressing the Aβ3-42 peptide. By combining cell-free and in vitro assays with nuclear magnetic resonance (NMR) and MS-based metabolomics, NMR molecular recognition studies, and atomic force microscopy, we identified feruloyl and p-coumaroylquinic acids flavan-3-ol glycosides and procyanidins as the main anti-Aβ components of hop.

Zhang SG et al. (2022) Nonlinear Dynamics Psychol Life Sci "Dynamic Markers for Chaotic Motion in C. elegans."

Singhvi A, Hastings HM, Susman KM, Zhang SG, Magnes J

[Nonlinear Dynamics Psychol Life Sci, 2022]

We describe the locomotion of Caenorhabditis elegans (C. elegans) using nonlinear dynamics. C. elegans is a commonly studied model organism based on ease of maintenance and simple neurological structure. In contrast to traditional microscopic techniques, which require constraining motion to a 2D microscope slide, dynamic diffraction allows the observation of locomotion in 3D as a time series of the intensity at a single point in the diffraction pattern. The electric field at any point in the far-field diffraction pattern is the result of a superposition of the electric fields bending around the worm. As a result, key features of the motion can be recovered by analyzing the intensity time series. One can now apply modern nonlinear techniques; embedding and recurrence plots, providing valuable insight for visualizing and comparing data sets. We found significant markers of low-dimensional chaos. Next, we implemented a minimal biomimetic simulation of the central pattern generator of C. elegans with FitzHugh-Nagumo neurons, which exhibits undulatory oscillations similar to those of the real C. elegans. Finally, we briefly describe the construction of a biomimetic version of the Izquierdo and Beer robotic worm using Keener's implementation of the Nagumo et al. circuit.

Li H et al. (2023) Phytother Res "Hordenine improves Parkinsonian-like motor deficits in mice and nematodes by activating dopamine D2 receptor-mediated signaling."

Li W, Chen Z, Li F, Huang C, Gao M, Zhang Y, Wu X, Fan S, Li H, Wang G, Zhu J, Zhou Z, Huang X, Zhang X, Jiang X, Luo L

[Phytother Res, 2023]

Parkinson's disease (PD) is a chronic neurodegenerative disease characterized by selective loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the striatum, leading to dopamine (DA) deficiency in the striatum and typical motor symptoms. A small molecule as a dietary supplement for PD would be ideal for practical reasons. Hordenine (HOR) is a phenolic phytochemical marketed as a dietary supplement found in cereals and germinated barley, as well as in beer, a widely consumed beverage. This study was aimed to identify HOR as a dopamine D2 receptor (DRD2) agonist in living cells, and investigate the alleviative effect and mechanism of HOR on PD-like motor deficits in mice and nematodes. Our results firstly showed that HOR is an agonist of DRD2, but not DRD1, in living cells. Moreover, HOR could improve the locomotor dysfunction, gait, and postural imbalance in MPTP- or 6-OHDA-induced mice or Caenorhabditis elegans, and prevent α-synuclein accumulation via the DRD2 pathway in C. elegans. Our results suggested that HOR could activate DRD2 to attenuate the PD-like motor deficits, and provide scientific evidence for the safety and reliability of HOR as a dietary supplement.

Gerdt S et al. (1997) Glycobiology "Isolation and structural analysis of three neutral glycosphingolipids from a mixed population of Caenorhabditis elegans (Nematoda:Rhabditida)."

Lochnit G, Dennis RD, Gerdt S, Geyer R

[Glycobiology, 1997]

The free-living nematode, Caenorhabditis elegans, has been proposed and analyzed as a prototypic model for parasitic nematodes. In order to study whether there is a structural basis for the proposed analogy with respect to nematode glycoconjugates, we have analyzed Caenorhabditis elegans glycosphingolipids. Three, simple neutral glycosphingolipid components of the neutral glycolipid fraction were isolated by high-performance liquid chromatography. Structural analysis was performed by methylation analysis, exoglycosidase cleavage, matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry, and ceramide analysis. The chemical structures have been determined as Glc beta 1Cer, Man beta 4Glc beta 1Cer and GlcNAc beta 3Man beta 4Glc beta 1Cer; that are characterized as belonging to the arthroseries of protostomial glycosphingolipids. The ceramide moiety of the parent glycosphingolipid-ceramide mono-hexoside was dominated by 2-hydroxy fatty acids, and a d17:1 spingoid-base with an iso- or anteiso-branched chain. The chemical composition of the three glycosphingolipids from Caenorhabditis elegans displayed close structural coincidence with the equivalent structures from the porcine parasitic nematode, Ascaris suum (G.Lochnit, R.D. Dennis, U.Zahringer, and R.Geyer, Glycoconjugate J., 1997), in support of this organism as a prototypic glycosphingolipid model for parasitic nematodes.

Beer, Katharina et al. (2017) International Worm Meeting "Retromer-associated proteins and PAD-1 control TAT-5 flippase activity to inhibit extracellular vesicle budding."

Nance, Jeremy, Stigloher, Christian, Wehman, Ann, Fazeli, Gholamreza, Beer, Katharina

[International Worm Meeting, 2017]

Cells release extracellular vesicles (EV) that can mediate intercellular communication to influence development and disease (Beer & Wehman, Cell Adh Migr 2017). Despite their pleiotropic functions, the molecular details of EV release are poorly understood, especially for plasma membrane budding (ectocytosis). Previously, we showed that TAT-5 phospholipid flippase activity inhibits ectocytosis and maintains the asymmetric localization of the lipid phosphatidylethanolamine (PE) in the inner leaflet of the plasma membrane (Wehman et al., Curr Biol 2011). In a screen for additional proteins that inhibit EV budding, we identified new TAT-5 regulators related to the retromer recycling pathway (PI3Kinase VPS-34, Beclin1 homolog BEC-1, and RME-8) together with the Dopey domain protein PAD-1. PI3K, RME-8, and sorting nexins are required for the localization of TAT-5 to the plasma membrane, which is important to maintain PE asymmetry. PAD-1 also localizes to the plasma membrane, but is not required for TAT-5 localization. Rather, PAD-1 is required for the lipid flipping activity of TAT-5, further supporting the model that PE asymmetry regulates plasma membrane budding. Our study identifies new proteins that regulate extracellular vesicle release and pinpoints TAT-5 and phosphatidylethanolamine as key regulators of plasma membrane budding. Understanding the mechanisms of EV release will enable us to determine the in vivo roles of EVs during development and homeostasis.

Sinha, Amit et al. (2015) International Worm Meeting "Genome wide analysis of adaptation to acidic environments of the extremophile Turbatrix aceti."

Alkema, Mark, Sinha, Amit, Sarkies, Peter, Pirri, Jennifer

[International Worm Meeting, 2015]

The nematode Turbatrix aceti, commonly known as the vinegar eel, represents one of the rare examples of metazoans that are uniquely adapted to thrive in highly acidic environments. It can grow at a remarkable pH range from 2.5 to 9. To determine the molecular basis of mechanisms of adaptation to extreme environments we initiated a whole genome sequencing of T. aceti. Using Illumina sequencing platform, we have obtained about 11 Gigabases of data, from 55 million paired-end reads at 100 base pair length. We have assembled a first draft version of T. aceti genome to a total size of about 51 Megabases (Mb), indicating an average coverage of about 211-fold over the whole genome. This draft genome is comprised of around 83,000 contigs, with the largest contig at 78kb, and a N50 contig size of 2kb. Using the SNAP gene prediction software on this draft genome, we have identified about 25,000 protein coding genes. To improve the quality and contiguity of the genome assembly, we are currently using very long-read sequencing technology from Pacific Biosciences. T. aceti belongs to Clade IV of nematode phylogeny, which also harbors the beer mat nematode Panagrellus redivivus and many parasitic nematode species including, Strongyloides, and Globodera. We are analyzing the current set of gene predictions to search for novel gene families and protein domains specifically enriched in T. aceti as compared to other sequenced nematode genomes. Furthermore, to specifically identify genes potentially required for acid tolerance, we are using RNAseq to compare the gene expression profiles of T. aceti grown in acidic media versus in neutral media. We will present our analysis which should provide new insights to the physiological and genetic basis of adaptations to extreme environments.

Tinya Fleming et al. (2003) International Worm Meeting "The FGF homolog EGL-17 acts with its receptor EGL-15 to repel migrating CANs"

Tinya Fleming, Fred Wolf, Gian Garriga

[International Worm Meeting, 2003]

Fibroblast Growth Factors (FGF) and their receptors (FGFR) are required for cell migrations in many organisms. In C. elegans the FGF homolog EGL-17 acts through its receptor EGL-15 to attract the migrating sex myoblasts (SMs)1. We have found that egl-17 and egl-15 also play a role in the migrations of the CANs (canal-associated neurons), a pair of bilaterally symmetric neurons that migrate posteriorly during embryogenesis.Although egl-17 and egl-15 mutations do not display striking CAN migration defects on their own, they significantly enhanced the CAN migration defects seen in vab-8 and unc-34 mutants. An egl-17 translational fusion to GFP expressed in only two anterior head cells during the time of CAN migration, raising the possibility that EGL-17 repels the CANs posteriorly. To test this possibility we expressed egl-17 ectopically. Ectopic expression of egl-17 in the head rescued the CAN migration defects of vab-8; egl-17 and unc-34; egl-17 double mutants, while ectopic expression of egl-17 globally or posteriorly enhanced the defects of vab-8 and unc-34 mutants. These results suggest that EGL-17 functions as a repellent in CAN migration. This model predicts that EGL-15 should function cell autonomously in the CANs. In support of this model, we found that a Pceh-10::egl-15 transgene, which is predicted to express in the CANs and only a few other neurons, partially rescued the defects of a vab-8; egl-15 double mutant. We are currently testing if unc-34; egl-15 double mutants are also rescued by the transgene.There are two isoforms of EGL-15, which have separate functions. The EGL-15(5A) isoform is required for SM migration and the EGL-15(5B) isoform is required for viability.2 Preliminary results suggest that both EGL-15 isoforms are involved in CAN migration. We are currently characterizing the roles of the EGL-15 isoforms in directing CAN migration.1Burdine, R.D. et al. (1998) Development. 125, 1083-1093; 2S.J. Goodman and M.J. Stern (personal comm.)

Zucker-Aprison E et al. (1986) Worm Breeder's Gazette "the heptamers in the vitellogenin promoters: an update."

Blumenthal TE, Zucker-Aprison E, Cane J

[Worm Breeder's Gazette, 1986]

There are two heptamers repeated multiple times upstream of the C. enin genes. In order to obtain evidence for or against the functional importance of these heptamers we have investigated their evolutionary stability. We sequenced the homologous promoters from C. briggsae and the only C. enin promoter remaining unsequenced vit-3. This brings the total number of nematode vitellogenin promoters sequenced to eleven. The data are shown schematically in the Figure. Box 1 TGTCAAT, is shown as rectangles; Box 2 CTGATAA is shown as ovals. In general the heptamers have beer very highly conserved while the sequences between them have diverged considerably. In particular there has been strong conservation of the Box 1 heptamers centered at -45 ( just upstream of the TArA box)those at -180 (which we have suggested may be at the 5' border of the promoter regions) and at least one Box 1 between -45 and -180. In each case the locations and sequences of at least these Box 1 heptamers and at least one Box 2 heptamer per promoter have been conserved. This data strongly supports the hypothesis that Box 1 and Box 2 are involved in vit promoter function. We are initiating experiments to determine the relationship between the two heptamers and the three modes of regulation: sex stage and tissue. {Figure 1} We have noted previously the presence of Box 2 in the vertebrate vitellogenin promoters. Klein-Hitpass et al. (Cell 46 1053) have tested the idea that this heptamer plays a role in Xenopus vitellogenin gene induction by estrogen in a transient expression assay using a human mammary cell line. They present evidence that it is a binding site for an activator protein required for estrogen induction but not the site for estrogen receptor itself. They name it the 'elegans box'. Does this mean that the regulatory protein that binds to this sequence in the C. e is also present in human mammary cells?