Hansen EL et al. (1971) Experientia "Effect of insect hormones on nematodes in axenic culture."

Hansen EL, Buecher EJ

[Experientia, 1971]

Insect juvenile hormones (JH) or JH mimetics have been shown to affect development of nematodes: Trichinella spiralis larvae and fourth stage Phocanema decipiens were inhibited, and abnormal morphology was seen in Heterodera schactii. The effects of insect hormones and analogues on development of several free-living and parasitic nematodes cultured axenically are described in the present paper.

Charlesworth AG et al. (2019) Cell "Next-Gen Learning: The C.elegans Approach."

Claycomb JM, Seroussi U, Charlesworth AG

[Cell, 2019]

In this issue, Moore etal. and Posner etal., provide evidence for how the activity of the nervous system in C.elegans results in gene expression changes in the germline to pass on parental experiences and learned behavior to their progeny.

Rebecca M Fox et al. (2005) International Worm Meeting "MAPCeL: Microarray Profiling C. elegans Cells"

Thomas Brodigan, Rebecca M Fox, Michael Krause, Kellen Olszewski, Susan J Barlow, Joan McDermott, W Clay Spencer, David M Miller, Stephen E Von Stetina

[International Worm Meeting, 2005]

Individual C. elegans cells can be easily visualized in vivo with GFP reporters but, owing to their small size, they are generally inaccessible for molecular analysis. We have now developed new methods for the isolation and gene expression profiling of GFP marked C. elegans cells (MAPCeL Microarray Profiling C. elegans Cells). In this strategy, GFP cells are isolated by FACS from in vitro cultures and RNA extracted for application to the C. elegans Affymetrix array. To demonstrate the utility of our approach, we have profiled cells in the embryonic motor circuit; we have identified genes that are differentially expressed in body muscle cells and in each of the three classes of embryonic ventral cord motor neurons (DA, DB, DD). Microarray data in each case were validated by strong correlation with genes known to be expressed in these cells as well as with GFP reporters that we constructed (~80%). For example, our MAPCeL data from inhibitory DD motor neurons confirms enrichment of transcripts required for the GABA phenotype (i.e. unc-25, unc-30, unc-47, snf-11). Conversely, the excitatory DA and DB motor neurons express cholinergic genes (unc-17, cha-1) as well as specific transcription factors that regulate cholinergic signaling (unc-3, unc-4). These data can now be used to identify novel genes with key roles in the locomotory circuit. For example, we have shown that DA motor neurons express a surprisingly diverse array of G-protein coupled receptors with the potential to modulate excitatory activity in response to neuropeptides as well as classical neurotransmitters. MAPCeL data from body muscle cells lead to the discovery that ACR-16 is a component of the levamisole-insensitive nicotinic ACh receptor (See Touroutine et al., this meeting). Finally, by identifying cohorts of genes with common expression patterns we can now search for cis-regulatory elements necessary for cell-specific expression. For example, we have identified enhancer element candidate motifs in the body wall muscle and DA motor neuron datasets (see Olszewski et al, this meeting). We conclude that MAPCeL can be used to generate reliable profiles of cell specific gene expression in the motor circuit and that these data will be valuable resources for correlating gene expression with function.1.Fox, RM, Von Stetina, SE, Barlow, SJ, Shaffer, C, Olszewski, KL, Moore, JH, Dupuy, D, Vidal, M, Miller, DM III. A gene expression fingerprint of C. elegans Embryonic motor neurons. BMC Genomics 2005, 6:42.

Sim C et al. (2013) Front Physiol "Insulin signaling and the regulation of insect diapause."

Denlinger DL, Sim C

[Front Physiol, 2013]

A rich chapter in the history of insect endocrinology has focused on hormonal control of diapause, especially the major roles played by juvenile hormones (JHs), ecdysteroids, and the neuropeptides that govern JH and ecdysteroid synthesis. More recently, experiments with adult diapause in Drosophila melanogaster and the mosquito Culex pipiens, and pupal diapause in the flesh fly Sarcophaga crassipalpis provide strong evidence that insulin signaling is also an important component of the regulatory pathway leading to the diapause phenotype. Insects produce many different insulin-like peptides (ILPs), and not all are involved in the diapause response; ILP-1 appears to be the one most closely linked to diapause in C. pipiens. Many steps in the pathway leading from perception of daylength (the primary environmental cue used to program diapause) to generation of the diapause phenotype remain unknown, but the role for insulin signaling in mosquito diapause appears to be upstream of JH, as evidenced by the fact that application of exogenous JH can rescue the effects of knocking down expression of ILP-1 or the Insulin Receptor. Fat accumulation, enhancement of stress tolerance, and other features of the diapause phenotype are likely linked to the insulin pathway through the action of a key transcription factor, FOXO. This review highlights many parallels for the role of insulin signaling as a regulator in insect diapause and dauer formation in the nematode Caenorhabditis elegans.

Fodor A et al. (1989) General & Comparative Endocrinology "Effects of precocene analogs on the nematode Caenorhabditis remanei (var. Bangaloreiensis). 2. Competitions with a juvenile hormone analog (methoprene)."

Timar T, Fodor A

[General & Comparative Endocrinology, 1989]

Fourteen 7-alkoxy-2,2-dimethylchromenes were synthetized and studied in JH competition experiments: prococenes (Ps) PI and PII, and synthetic analogs (PAs) including (i) three with both antiallatal and P-like activities: 7-ethoxy-PII (7-EPII); 7-(prop-2-ynyloxy)-2,2-dimethylchromene (PPI); and 6-methoxy-7-(prop-2-yynyloxy)-2,2-dimethylchromene (PPIII); (ii) six without antiallatal activity, exerting P-like activity in nematodes; and (iii) three without either antiallatal or P-like activity, but with a strong nematocidal effect. Within the dose range 8-1000 ug/ml, different concentrations of each PA were applied to nematode growth medium which did or did not contain 1000 ug methoprene (a juvenile hormone analog JHA)/ml. Plates inoculated with Caenorhabditis embryos were incubated and scored for developmentally affected survivors. The JHA did not compete with any PA mentioned as (iii). It competed moderately with some nonantiallatal PAs (8-Me-PPI, 8-MeO-PPI, and 3,4-diCl-PPI) with strong P-like and nematocidal activities. The JHA competed most efficiently with all Ps, antiallatal PAs, and two nonantiallatal PAs (PPII and thio-PI) which exerted severe P-like activities in nematodes. Parameters assumed to be indicators of the P-like (rather than nematocidal) activity of the PAs proved more sensitive to the JHA than those of nematocidal activity. Whether the JH-compensable P-like activity of some PAs can be regarded as a real anti-JH action needs further clarification.

Landis GN et al. (2020) J Gerontol A Biol Sci Med Sci "Metabolic Signatures of Life Span Regulated by Mating, Sex Peptide and Mifepristone/RU486 in Female Drosophila melanogaster."

Abdelmesieh M, Patel P, Wang T, Tower J, Wang L, Fan Y, Promislow DEL, Doherty DV, Lee S, Vroegop J, Wu J, Shen J, Landis GN, Yen CA, Wang I, Curran SP

[J Gerontol A Biol Sci Med Sci, 2020]

Mating and transfer of male Sex Peptide (SP), or transgenic expression of SP, causes inflammation and decreased life span in female Drosophila. Mifepristone rescues these effects, yielding dramatic increases in life span. Here targeted metabolomics data were integrated with further analysis of extant transcriptomic data. Each of seven genes positively correlated with life span were expressed in the brain or eye, and involved regulation of gene expression and signaling. Genes negatively correlated with life span were preferentially expressed in midgut and involved protein degradation, amino acid metabolism, and immune response. Across all conditions, life span was positively correlated with muscle breakdown product 1/3-methylhistadine and purine breakdown product urate, and negatively correlated with tryptophan breakdown product kynurenic acid, suggesting a SP-induced shift from somatic maintenance/turnover pathways to the costly production of energy and lipids from dietary amino acids. Some limited overlap was observed between genes regulated by mifepristone and genes known to be regulated by ecdysone, however, mifepristone was unable to compete with ecdysone for activation of an ecdysone-responsive transgenic reporter. In contrast, genes regulated by mifepristone were highly enriched for genes regulated by Juvenile Hormone (JH), and mifepristone rescued the negative effect of JH analog methoprene on life span in adult virgin females. The data indicate that mifepristone increases life span and decreases inflammation in mated females by antagonizing JH signaling downstream of male SP. Finally, mifepristone increased life span of mated, but not unmated, C. elegans, in two of three trials, suggesting possible evolutionary conservation of mifepristone mechanisms.

Fodor A et al. (1987) Worm Breeder's Gazette "competition of exogenous methoprene and precocenes in nematodes: the end of the story."

Timar T, Hosztafi S, Dinya Z, Fodor A, Kiss I

[Worm Breeder's Gazette, 1987]

We have accomplished a ten year long project aimed to learn whether competition between the juvenile hormone (JH) analogue methoprene (JHA) and precocenes (P's) (chromene derivatives capable to destruct the JH producing organ (CA) in sensitive insect species tissue specifically) in C. elegans (Fodor, et. al., Gen. Comp. Endcr. 46: p. 99 (1982)) can or cannot be explained by a comparable 'anti-JH' action of P's in nematodes. Neither JH or CA like organ has been discovered in nematodes so far. There are only a few indirect data showing that insect juvenile hormones may influence certain nematodes pathogenizing insects. We adopted a 'structure/activity' approach including design, synthesis and test P analogues on nematodes in the presence and absence of JHA. If (at least part of) those analogues which capable to destruct the CA of a sensitive insect (Locusta migratoria) were also effective in nematodes and their effect could be compensated by JHA exogenously, then this hormone (analogue) should play a physiological role in the P-poisoned nematodes. If those P's could be competed by JHA, which proved effective (as 'anti-JH' compounds) in insects, but those which exerted only aspecific toxicity could not be, then it would be logical to suggest, that P's are the same kind of 'suicide compounds' for nematodes as for insects. More than 200 P derivatives were synthesized (Tim r, Hosztafi) and tested on C. elegans (Fodor) and L. migratoria (Kiss). After a detailed quantitative structure/activity relation (QSAR) analysis ( Dinya, et. al., QSAR Strat. Des. Bioact. Compd. Proc. Eur. Symp. Struct.-Act. Relat. 5th (1984) Publ. 1985) several new P analogue were designed, synthesized and tested on L. migratoria and on C. remanei var. Bangaloriensis. (We choose this nematode strain because half of its population consists of males, therefore it is easy to distinguish male adultoids from other type of retarded worms.) Altogether, 121 molecules were retested C. remanei and 17 of them was found to exert some significant biological effect. These compounds were retested again several times both in the absence and in the presence of 1 mg/ml NGM dose of JHA: altogether, more that 144,000 C. remanei embryos were counted, treated and scored afterwards. The tests on nematodes were carried out as described in our attached paper. The most characteristic data concerning precocene activity in nematodes were the following: (1) LC50: the half lethal dose (in g/ml) at which half of the embryos develops to worms (calculated by probit analysis); (2) AD50: the dose ( g/ml) at which half of the embryos develops to normal adults; (3) EC50: the dose ( g/ml) at which half of the nematodes on the plates found as 'normal' fertile adults; (4) The maximum frequency of 'adultoid mini worms' during the experiments. [See Figures 1- 2] The main conclusions are the following: About structure/activity relations: (1) All the three (P1-P3) precocene is effective in nematodes and their effects can be compensated by exogenous JHA. (2) The longer the chain of the R7 substituent the less the effect of the compounds in nematodes. (3) The 7-proparglyoxy analogues are much more effective in nematodes than any other C7 substituted compound. (compare P1 to TT51; P2 to K460; P3 to TT80; TT56 to TT58 or 3,4-diCl-P1 (inactive) to FI121.) (4) The asymmetrically disubstituted analogues are much more effective than the symmetrically disubstituted ones (compare TT80 to K460). It is true, if R7 is longer than R6. (5) Me substitution at C5 position inactivates the originally potent P's (compare TT58 to TT51) but restore the activity of originally inactive (for instance, 7-sBuO-P1) analogues (compare it to TT56). 8-MeO substitution eliminate specific P activity (compare TT51 to K464). (6) Both 8-Me and 8-MeO substitution increase toxic rather than JH compatible biological activity of P's. 8-MeO analogues are more toxic than 8-Me ones, but the consequences of the action of 8-MeO compounds in nematodes can be cured more efficiently by JHA than those concerning 8-Me compounds (compare TT100 to K475). About JHA competition experiments: JHA competed the effects of all precocenes which effected both insects and nematodes. However, the data concerning K354 and FI121 show, that there are analogues which effective only in nematodes and their effects can also be cured by exogenous JHA. Although there are aspecifically toxic analogues (like K454 or 2,3,5-triMe-7 propargO-P1) which cannot be compensated by methoprene, we cannot conclude, that our data unambiguously support the idea of existence JH-like hormones in nematodes. It seems very probable, however, that JH-like compounds can interfere with the lethal metabolism of P's.

Moore RS et al. (2021) STAR Protoc "Protocol for transgenerational learned pathogen avoidance behavior assays in Caenorhabditis elegans."

Moore RS, Murphy CT, Kaletsky R

[STAR Protoc, 2021]

Animal experiences, including learned behaviors, can be passed down to several generations of progeny in a phenomenon known as transgenerational epigenetic inheritance. Yet, little is known regarding the molecular mechanisms regulating physiologically relevant transgenerational memories. Here, we present a method for <i>Caenorhabditis elegans</i> in which worms learn to avoid the pathogen <i>Pseudomonas aeruginosa</i> (PA14). Unlike previous protocols, this training paradigm, either using PA14 lawns or through exposure to a PA14 small RNA (P11), induces memory in four generations of progeny. For complete details on the use and execution of this protocol, please refer to Moore etal. (2019) and Kaletsky etal. (2020).

Fodor A et al. (1989) Gen Comp Endocrinol "Effects of precocene analogs on the nematode Caenorhabditis remanei (var. Bangaloreiensis). I. Structure/activity relations."

Sebok P, Varga E, Hosztafi S, Fodor A, Timar T, Kiss I, Soos J

[Gen Comp Endocrinol, 1989]

Precocenes (PI and PII) and 114 of their analogs (PAs) were synthetized and tested on C. remanei embryos for their precocene-like (P-like) activities resulting in unusual development at sublethal doses. The P-like activity was quantitated by plotting the probit of the percentage of the developmentally affected survivors against the (log) dose to obtain the EC plot and the half effective concentration (EC50). All five PAs (PI, PII, 7-ethoxy-PII, 7-(prop-2-ynyloxy)-PI, and 6-methoxy-7-(prop-2-ynyloxy)-PII) which exert both antiallatal activity in insects and P-like activity in nematodes are 7-alkoxy-substituted 2,2-dimethylchromenes. Both activities can be enhanced by an additional 6-MeO-substitution or by an asymmetric 6,7-dialkoxy-substitution, on condition that R-7 is longer than R-6. There are many more similarities than dissimilarities in the structural requirements needed for antiallatal and P-like activities. All but three nonantiallatal PAs effective in nematodes are 7-prop-2-ynyloxy-substituted; two are symmetrically 6,7-disubstituted, and one is heterosubstituted (thio-PI). All PAs with antiallatal but without P-like activity are 7-monosubstituted with a relatively long alkoxy group. Certain substitutions favor antiallatal activity and others P-like activity. The severe nematocidal effect of 6,7-methylenedioxy-2,2-dimethylchromene (inert in insects) is not accompanied by P-like activity. The present findings lend some indirect support to the supposition that JH-producing cells and/or JH-dependent function(s) might

Fox RM et al. (2005) BMC Genomics "A gene expression fingerprint of C. elegans embryonic motor neurons."

Fox RM, Dupuy D, Shaffer C, Olszewski KL, Moore JH, Von Stetina SE, Vidal M, Barlow SJ, Miller DM

[BMC Genomics, 2005]

BACKGROUND: Differential gene expression specifies the highly diverse cell types that constitute the nervous system. With its sequenced genome and simple, well-defined neuroanatomy, the nematode, C. elegans is useful model system in which to correlate gene expression with neuron identity. The UNC-4 transcription factor is expressed in thirteen embryonic motor neurons where it specifies axonal morphology and synaptic function. These cells can be marked with an unc-4::GFP reporter transgene. Here we describe a new, powerful strategy, Micro-Array Profiling of C. elegans cells (MAPCeL) for fingerprinting isolated C. elegans cells and confirm that this approach provides a comprehensive gene expression profile of unc-4::GFP motor neurons in vivo. RESULTS: Fluorescence Activated Cell Sorting (FACS) was used to isolate unc-4::GFP neurons from primary cultures of C. elegans embryonic cells. Microarray experiments detected 6,217 unique transcripts of which ~1,000 are enriched in unc-4::GFP neurons relative to the average nematode embryonic cell. The reliability of these data was validated by the detection of known cell-specific transcripts and by expression in UNC-4 motor neurons of GFP reporters derived from the enriched data set. In addition to genes involved in neurotransmitter packaging and release, the microarray data include transcripts for receptors to a remarkably wide variety of signaling molecules. The added presence of a robust array of G-protein pathway components is indicative of complex and highly integrated mechanisms for modulating motor neuron activity. Over half of the enriched genes (537) have human homologs, a finding that could reflect substantial overlap with the gene expression repertoire of mammalian motor neurons. CONCLUSIONS: We have described a microarray-based method, MAPCeL, for profiling gene expression in specific C. elegans motor neurons and provide evidence that this approach can reveal candidate genes for key roles in the differentiation and function of these cells. These methods can now be applied to generate a gene expression map of the C. elegans nervous system.