Fernandes de Abreu, D. A. et al. (2013) International Worm Meeting "The functional and regulatory organization of the C. elegans insulin-like peptide network."

Csikasz-Nagy, A., Fontana, W., Stroustrup, N., Fernandes de Abreu, D. A., Fardel, P., Ostojic, I., Antebi, A., Cornils, A., Keyes, W. D., Lee, K., Lopez Moyado, I. F., Regenass, M., Chen, Z., Nash, Z. M., Neagu, A., Liu, C., Caballero, A., Murphy, C., Vaggi, F., Sifoglu, D.

[International Worm Meeting, 2013]

C. elegans has 40 insulin-like peptide (ILPs) that regulate several processes, including longevity, dauer formation, pathogen resistance and thermotolerance. But how multiple ILPs interact to control physiology is not fully understood. To understand their function, we systematically assessed the effect of 35 different ILP deletion mutants in 8 physiological processes. Furthermore, to delineate the genetic interactions amongst ILPs, we tested the dauer entry phenotype of 53 different double mutants. We found that the ILP family has undergone functional and regulatory diversification where different ILPs regulate specific sets of processes and where each process is controlled by different combinations of ILPs, thus detailing the specifics of a graded combinatorial ILP code. We also analyzed the expression of each ILP in the 35 ILP mutants. The results revealed that the ILPs are organized into a network with specific ILP-to-ILP regulation. This ILP network has "small world" properties that are associated with efficient communication and computation. Connectivity motifs within this network suggest that the ILPs cooperate not only via compensation, expected for duplicated gene families, but also via feedback, feed-forward and cross-talk functionality. Integrative analysis of our systematic datasets revealed network mechanisms that contribute to robustness against gene perturbations and functional differences between ILPs. This analysis also mapped out the flow of information among the ILPs in the network, indicating how information from different parts of the network is processed and integrated during dauer entry.

Wu, T. et al. (2017) International Worm Meeting "Dissecting a network of the insulin-like peptides underlying olfactory learning."

Zhang, Y., Caballero, A., Alcedo, J., Choi, M., Katic, I., Regenass, M., Fernandes de Abreu, D., Ch'ng, Q., Wu, T.

[International Worm Meeting, 2017]

Insulin and insulin-like peptides (ILPs) act through conserved signaling pathways to regulate neural plasticity in both invertebrates and vertebrates. The genomes of many animals, including that of the humans, encode multiple ILPs. Our previous studies characterize two C. elegans ILPs that regulate a form of aversive olfactory learning in the nematode. These two ILPs interact with other ILP family members in a transcriptional network (Chen et al., 2013; Fernandes de Abreu et al., 2014). We hypothesize that multiple ILPs act as a network to regulate physiological events, including learning, in response to various contexts. To address this hypothesis, we have examined the learning ability in the deletion mutants of the ILPs in the network. We find that deleting ins-4, ins-8 or ins-35 significantly disrupt the aversive olfactory learning. We show that these ILPs are expressed in different sensory neurons and that the aversive training alters the neuronal expressions. In addition, other types of experience, such as pheromone exposure and starvation, regulate the expression of these ILPs differently. Together, these results support our hypothesis that ILPs regulate learning in an interactive network that responds to the environment and experience in a context-dependent manner.

Ullrich M et al. (2014) Nat Protoc "Bio-orthogonal labeling as a tool to visualize and identify newly synthesized proteins in Caenorhabditis elegans."

Gotz J, Banister S, Nicholas HR, Chew YL, Ullrich M, Liang V, Kassiou M, Zaw T, Berber S, Song X, Lam H

[Nat Protoc, 2014]

In this protocol we describe the incorporation of bio-orthogonal amino acids as a versatile method for visualizing and identifying de novo-synthesized proteins in the roundworm Caenorhabditis elegans. This protocol contains directions on implementing three complementary types of analysis: 'click chemistry' followed by western blotting, click chemistry followed by immunofluorescence, and isobaric tags for relative and absolute quantification (iTRAQ) quantitative mass spectrometry. The detailed instructions provided herein enable researchers to investigate the de novo proteome, an analysis that is complicated by the fact that protein molecules are chemically identical to each other, regardless of the timing of their synthesis. Our protocol circumvents this limitation by identifying de novo-synthesized proteins via the incorporation of the chemically modifiable azidohomoalanine instead of the natural amino acid methionine in the nascent protein, followed by facilitating the visualization of the resulting labeled proteins in situ. It will therefore be an ideal tool for studying de novo protein synthesis in physiological and pathological processes including learning and memory. The protocol requires 10 d for worm growth, liquid culture and synchronization; 1-2 d for bio-orthogonal labeling; and, with regard to analysis, 3-4 d for western blotting, 5-6 d for immunofluorescence or ~3 weeks for mass spectrometry.

Zarkower D et al. (1994) Worm Breeder's Gazette "mab-3 YAC Rescue"

De Bono M, Hodgkin JA, Zarkower D

[Worm Breeder's Gazette, 1994]

mab-3 YAC rescue David Zarkower, Mario de Bono, and Jonathan Hodgkin MRC Laboratory of Molecular Biology, Cambridge, England

Sakoguchi H et al. (2016) Biosci Biotechnol Biochem "Screening of biologically active monosaccharides: growth inhibitory effects of d-allose, d-talose, and l-idose against the nematode Caenorhabditis elegans."

Izumori K, Yoshihara A, Sakoguchi H, Sato M

[Biosci Biotechnol Biochem, 2016]

We compared the growth inhibitory effects of all aldohexose stereoisomers against the model animal Caenorhabditis elegans. Among the tested compounds, the rare sugars d-allose (d-All), d-talose (d-Tal), and l-idose (l-Ido) showed considerable growth inhibition under both monoxenic and axenic culture conditions. 6-Deoxy-d-All had no effect on growth, which suggests that C6-phosphorylation by hexokinase is essential for inhibition by d-All.

Sakoguchi H et al. (2016) Bioorg Med Chem Lett "Growth inhibitory effect of d-arabinose against the nematode Caenorhabditis elegans: Discovery of a novel bioactive monosaccharide."

Shintani T, Izumori K, Sato M, Sakoguchi H, Okuma K, Yoshihara A

[Bioorg Med Chem Lett, 2016]

Biological activities of unusual monosaccharides (rare sugars) have largely remained unstudied until recently. We compared the growth inhibitory effects of aldohexose stereoisomers against the animal model Caenorhabditis elegans cultured in monoxenic conditions with Escherichia coli as food. Among these stereoisomers, the rare sugar d-arabinose (d-Ara) showed particularly strong growth inhibition. The IC50 value for d-Ara was estimated to be 7.5mM, which surpassed that of the potent glycolytic inhibitor 2-deoxy-d-glucose (19.5mM) used as a positive control. The inhibitory effect of d-Ara was also observed in animals cultured in axenic conditions using a chemically defined medium; this excluded the possible influence of E. coli. To our knowledge, this is the first report of biological activity of d-Ara. The d-Ara-induced inhibition was recovered by adding either d-ribose or d-fructose, but not d-glucose. These findings suggest that the inhibition could be induced by multiple mechanisms, for example, disturbance of d-ribose and d-fructose metabolism.

Yoshihara A et al. (2019) Bioorg Med Chem Lett "Growth inhibition by 1-deoxy-d-allulose, a novel bioactive deoxy sugar, screened using Caenorhabditis elegans assay."

Sakoguchi H, Fleet GWJ, Izumori K, Shintani T, Sato M, Yoshihara A

[Bioorg Med Chem Lett, 2019]

The biological activities of deoxy sugars (deoxy monosaccharides) have remained largely unstudied until recently. We compared the growth inhibition by all 1-deoxyketohexoses using the animal model Caenorhabditis elegans. Among the eight stereoisomers, 1-deoxy-d-allulose (1d-d-Alu) showed particularly strong growth inhibition. The 50% inhibition of growth (GI₅₀) concentration by 1d-d-Alu was estimated to be 5.4mM, which is approximately 10 times lower than that of d-allulose (52.7mM), and even lower than that of the potent glycolytic inhibitor, 2-deoxy-d-glucose (19.5mM), implying that 1d-d-Alu has a strong growth inhibition. In contrast, 5-deoxy- and 6-deoxy-d-allulose showed no growth inhibition of C. elegans. The inhibition by 1d-d-Alu was alleviated by the addition of d-ribose or d-fructose. Our findings suggest that 1d-d-Alu-mediated growth inhibition could be induced by the imbalance in d-ribose metabolism. To our knowledge, this is the first report of biological activity of 1d-d-Alu which may be considered as an antimetabolite drug candidate.

Katane M et al. (2020) Biochim Biophys Acta Proteins Proteom "Biochemical characterization of d-aspartate oxidase from Caenorhabditis elegans: Its potential use in the determination of free D-glutamate in biological samples."

Katane M, Sekine M, Nakayama K, Homma H, Kuwabara H, Saitoh Y, Miyamoto T

[Biochim Biophys Acta Proteins Proteom, 2020]

d-Aspartate oxidase (DDO) is a flavin adenine dinucleotide (FAD)-containing flavoprotein that stereospecifically acts on acidic D-amino acids (i.e., free d-aspartate and D-glutamate). Mammalian DDO, which exhibits higher activity toward d-aspartate than D-glutamate, is presumed to regulate levels of d-aspartate in the body and is not thought to degrade D-glutamate in vivo. By contrast, three DDO isoforms are present in the nematode Caenorhabditis elegans, DDO-1, DDO-2, and DDO-3, all of which exhibit substantial activity toward D-glutamate as well as d-aspartate. In this study, we optimized the Escherichia coli culture conditions for production of recombinant C. elegans DDO-1, purified the protein, and showed that it is a flavoprotein with a noncovalently but tightly attached FAD. Furthermore, C. elegans DDO-1, but not mammalian (rat) DDO, efficiently and selectively degraded D-glutamate in addition to d-aspartate, even in the presence of various other amino acids. Thus, C. elegans DDO-1 might be a useful tool for determining these acidic D-amino acids in biological samples.

Eberhardt AG et al. (2008) Vet Parasitol "The Strongyloides (Nematoda) of sheep and the predominant Strongyloides of cattle form at least two different, genetically isolated populations."

Mayer WE, Eberhardt AG, Streit A, Bonfoh B

[Vet Parasitol, 2008]

Strongyloides sp. (Nematoda) are very wide spread small intestinal parasites of vertebrates that can form a facultative free-living generation. Most authors considered all Strongyloides of farm ruminants to belong to the same species, namely Strongyloides papillosus (Wedl, 1856). Here we show that, at least in southern Germany, the predominant Strongyloides found in cattle and the Strongyloides found in sheep belong to separate, genetically isolated populations. While we did find mixed infections in cattle, one form clearly dominated. This variety, in turn, was never found in sheep, indicating that the two forms have different host preferences. We also present molecular tools for distinguishing the two varieties, and an analysis of their phylogenetic relationship with the human parasite Strongyloides stercoralis and the major laboratory model species Strongyloides ratti. Based on our findings we propose that Strongyloides from sheep and the predominant Strongyloides from cattle should be considered separate species as it had already been proposed by [Brumpt, E., 1921. Recherches sur le determinisme des sexes et de l''evolution des Anguillules parasites (Strongyloides). Comptes rendu hebdomadaires des seances et memoires de la Societe de Biologie et de ses filiales 85, 149-152], but was largely ignored by later authors. For nomenclature, we follow [Brumpt, E., 1921. Recherches sur le determinisme des sexes et de l''evolution des Anguillules parasites (Strongyloides). Comptes rendu hebdomadaires des seances et memoires de la Societe de Biologie et de ses filiales 85, 149-152] and use the name S. papillosus for the Strongyloides of sheep and the name Strongyloides vituli for the predominant Strongyloides of cattle.

Shintani T et al. (2019) J Appl Glycosci (1999) "D-Allose, a Stereoisomer of D-Glucose, Extends the Lifespan of Caenorhabditis elegans via Sirtuin and Insulin Signaling."

Izumori K, Sakoguchi H, Yoshihara A, Shintani T, Sato M

[J Appl Glycosci (1999), 2019]

D-Allose (D-All), C-3 epimer of D-glucose, is a rare sugar known to suppress reactive oxygen species generation and prevent hypertension. We previously reported that D-allulose, a structural isomer of D-All, prolongs the lifespan of the nematode Caenorhabditis elegans. Thus, D-All was predicted to affect longevity. In this study, we provide the first empirical evidence that D-All extends the lifespan of C. elegans. Lifespan assays revealed that a lifespan extension was induced by 28 mM D-All. In particular, a lifespan extension of 23.8 % was achieved (p< 0.0001). We further revealed that the effects of D-All on lifespan were dependent on the insulin gene daf-16 and the longevity gene sir-2.1, indicating a distinct mechanism from those of other hexoses, such as D-allulose, with previously reported antiaging effects.