Burket CT et al. (2000) East Coast Worm Meeting "dig-1 encodes an adhesion molecule involved in sensory map formation."

Hubbard S, Burket CT, Ryder EF

[East Coast Worm Meeting, 2000]

We are interested in the development of topographic maps. Topographic maps coordinately map spatial information from the environment to the brain. We are studying the maps formed by two sets of head sensory neurons in C. elegans, the IL1's (visualized by an unc-5::GFP construct kindly provided by J. Culotti) and the IL2's (visualized by DiO staining; C. Bargmann, pers. comm.). Currently, we are studying mutations in the gene dig-1 that affect the formation of these maps. In dig-1 mutant animals, IL1 and IL2 sensory processes are aberrant, and sometimes fail to reach their normal destinations in the nose. Mutant animals exhibit additional characteristics consistent with a defect in cell adhesion. dig-1 has been mapped to a region on chromosome III near sma-3. Two dig-1 alleles show changes by PCR and Southern analysis in a very large cell adhesion molecule in this region (K07E12.1; predicted cDNA about 40 kb). We have sequenced the affected regions of this gene in both alleles. Allele nu336 is a point mutation towards the 5' end of the gene resulting in a serine being changed to a phenylalanine. Allele n1480 is a rearrangement involving about 900 base pairs towards the 3' end of the gene. It is not yet clear whether this rearrangement would result in truncation of the predicted gene product, although this seems a likely possibility. Interestingly, the phenotype of the nu336 allele is more severe than that of the n1480 allele. We are conducting northern and RT-PCR experiments, as well as constructing a promoter::GFP fusion, to determine the cDNA structure and expression patterns of the dig-1 gene. CB was supported by a GAANN fellowship from the US DOEd (P200A50010). EFR is supported by a NSF CAREER Award (IBN-9984662).

Burket CT et al. (1998) East Coast Worm Meeting "Characterization of dig-1 and mig-10, two genes involved in sensory map formation."

Roach E, Hubbard S, Ryder EF, Burket CT, Rusiecki D

[East Coast Worm Meeting, 1998]

Many sensory systems map spatial information from the external world onto the brain in the form of a topographic map. We are interested in the development of topographic maps formed by two sets of head sensory neurons in C. elegans, the IL1's (visualized by an unc-5::GFP construct kindly provided by J. Culotti) and the IL2's (visualized by DiO Staining; C. Bargmann, pers. comm.) We are studying mutations in two genes, dig-1 and mig-10, that affect these topographic maps. In dig-1 mutant animals, IL1 and IL2 sensory processes follow aberrant paths, and sometimes fail to reach their normal destinations in the nose (WBG 14(1):49). Two dig-1 alleles show rearrangements in a very large candidate cell adhesion molecule by Southern blot analysis. We are using PCR to determine the precise molecular basis of these mutations. In addition, we are performing RNAi using sequence from the candidate gene to try to phenocopy the mutant phenotype. In mig-10 mutant animals, axons of neurons in the IL2 sensory map sometimes follow aberrant paths, or fail to reach their normal destinations in the nerve ring. mig-10 encodes a molecule that contains homology to proteins of the Grb family, which are involved in signal transduction (Manser et al., 1997. Dev. Biol. 184, 150-164.). We are collaborating with the Manser lab to look at expression patterns of mig-10 using GFP fusions. We also plan to perform a mosaic analysis to determine the cells necessary for the function of this gene in the formation of the sensory map.

Burket CT et al. (2006) Dev Biol "The C. elegans gene dig-1 encodes a giant member of the immunoglobulin superfamily that promotes fasciculation of neuronal processes."

Berninsone PM, Hull LC, Higgins CE, Ryder EF, Burket CT

[Dev Biol, 2006]

The adhesion of growing neurites into appropriate bundles or fascicles is important for the development of correct synaptic connectivity in the nervous system. We describe fasciculation defects of animals with mutations in the C. elegans gene dig-1 and show that dig-1 encodes a giant molecule (13,100 amino acids) of the immunoglobulin superfamily. Five new alleles of dig-1 were isolated in a screen for mutations affecting the morphology or function of several classes of head sensory neurons. Mutants showed process defasciculation of several classes of neurons. Analysis of a temperature-sensitive allele revealed that dig-1 is required during embryogenesis for normal process fasciculation of one class of head sensory neuron. Partial sequencing of two alleles, RNA interference (RNAi) and rescuing experiments showed that dig-1 encodes a giant molecule of the immunoglobulin superfamily. DIG-1 protein contains many domains associated with adhesion, is likely secreted, and has some features of proteoglycans. dig-1 mutants were originally isolated due to their displaced gonads [Thomas, J.H., Stern, M.J., Horvitz, H.R., 1990. Cell interactions coordinate the development of the C. elegans egg-laying system. Cell 62, 1041-52]; thus, dig-1 alleles were also characterized for their effects on gonad placement. Mutant phenotypes suggest that DIG-1 may mediate cell movement as well as process fasciculation and that different regions of the protein may mediate these functions.

CT Burket et al. (1999) International C. elegans Meeting "Molecular characterization of mutations in dig-1, a gene involved in sensory map formation."

S Hubbard, CT Burket, EF Ryder

[International C. elegans Meeting, 1999]

We are interested in the development of topographic maps. Topographic maps coordinately map spatial information from the environment to the brain. We are studying the maps formed by two sets of head sensory neurons in C. elegans , the IL1's (visualized by an unc-5 ::GFP construct kindly provided by J. Culotti) and the IL2's (visualized by DiO staining; C. Bargmann, pers. comm.). Currently, we are studying mutations in the gene dig-1 that affect the formation of these maps. In dig-1 mutant animals, IL1 and IL2 sensory processes are aberrant, and sometimes fail to reach their normal destinations in the nose (WBG 14(1):49). Two dig-1 alleles show changes by PCR and Southern analysis in a very large candidate cell adhesion molecule found on cosmid K07E12. One allele, dig-1(n1480) , was created by gamma ray mutagenesis, and shows a small rearrangement in the 3' end of the candidate gene. A second allele, dig-1(nu336) , occurred during an EMS mutagenesis of a strain containing the unc-5 ::GFP marker as a non-integrated array. The array integrated during the mutagenesis, and segregated with the dig-1 mutation, suggesting that the integration caused the mutation. We have now determined by PCR that the change we observed in the candidate gene was not due to this insertion, but instead is due to a point mutation resulting in an RFLP near the 5' end of the candidate gene. We are now separating the GFP insertion from the RFLP to determine whether the RFLP is solely responsible for the phenotype of nu336 . We will then sequence the affected regions of both this allele and n1480 in order to determine the precise molecular basis of the mutations. In addition, we are conducting RNAi experiments to phenocopy the mutant phenotype, as well as Northern analysis to determine cDNA structure and expression patterns of the candidate gene.

Ropiak HM et al. (2016) J Agric Food Chem "Structure-activity relationship of condensed tannins and synergism with trans-cinnamaldehyde against Caenorhabditis elegans."

Thamsborg SM, Ropiak HM, Mueller-Harvey I, Williams AR, Ramsay A, Desrues O

[J Agric Food Chem, 2016]

Parasitic gastrointestinal nematodes (GIN) of livestock are increasingly developing resistance to synthetic nematocidal drugs. Moreover, the use of nematocides can induce ecotoxicity by affecting free-living nematodes. Condensed tannins (CT) are a structurally diverse group of bioactive plant compounds possessing anthelmintic activity against GIN. We investigated the relationship between the chemical structure of contrasting, purified CT and nematocidal effects using Caenorhabditis elegans. We also explored whether the nematocidal activity of CT could synergize with trans-cinnamaldehyde (CIN). A non-significant correlation was evident between the ability of CT fractions to inhibit C. elegans motility and the molar proportion of prodelphinidin subunits in purified CT samples. Synergistic inhibition of motility was achieved by combinations of CT and CIN. Galloylation of procyanidins was also a key factor for synergy. To increase the nematocidal effect of CT, plant sources containing CT with specific structural features could be selected and combined with compounds acting in synergy.

Li H et al. (2022) Sci Total Environ "Direct toxicity of environmentally persistent free radicals to nematode Caenorhabditis elegans after excluding the concomitant chemicals."

Liu Y, Li H, Steinberg C, Zuo N, Pan B, Lang D, Xing B

[Sci Total Environ, 2022]

Environmentally persistent free radicals (EPFRs) have attracted extensive attention due to their potential toxicity. However, EPFRs-containing particles always coexist with their parent organic contaminants and intermediate degradation products (IM), which may have hindered the toxicity assessment of EPFRs. In this study, the toxicity of EFFRs was specifically verified after comparing the systems without EPFRs, such as the immediate mixture of catechol (CT) and particles, solutions of CT only, IM extracted from the particles, as well as particles after EPFRs quenching. Caenorhabditis elegans (C. elegans) were used as model organisms. Our results showed that EPFRs-containing particles (Si-Al-CT) exhibited significant toxicity to C. elegans, but not for the parent chemical CT and IM on the particles. Higher levels of reactive oxygen species (ROS) and malondialdehyde (MDA) in the Si-Al-CT system were attributed to the mediated generation of -O₂^- and -OH via EPFRs. EPFRs could increase gene expressions related not only to oxidative stress and biotransformation in C. elegans, but also to indications of disturbances in energy homeostasis, survival, proliferation, cell and embryonic development. Overall, these results confirmed the direct toxicity of EPFRs and highlighted the key role of EPFRs which may be neglected in assessing the environmental risks of organic contaminants.

Bjork P et al. (2002) Mol Biol Cell "A novel conserved RNA-binding domain protein, RBD-1, is essential for ribosome biogenesis."

Wieslander L, Burglin TR, Tong YG, Bauren G, Hellman U, Bjork P, Jin S

[Mol Biol Cell, 2002]

Synthesis of the ribosomal subunits from pre-rRNA requires a large number of trans-acting proteins and small nucleolar ribonucleoprotein particles to execute base modifications, RNA cleavages, and structural rearrangements. We have characterized a novel protein, RNA-binding domain-1 (RBD-1), that is involved in ribosome biogenesis. This protein contains six consensus RNA-binding domains and is conserved as to sequence, domain organization, and cellular location from yeast to human. RBD-1 is essential in Caenorhabditis elegans. In the dipteran Chironomus tentans, RBD-1 (Ct-RBD-1) binds pre-rRNA in vitro and anti-Ct-RBD-1 antibodies repress pre-rRNA processing in vivo. Ct-RBD-1 is mainly located in the nucleolus in an RNA polymerase I transcription-dependent manner, but it is also present in discrete foci in the interchromatin and in the cytoplasm. In cytoplasmic extracts, 20-30% of Ct-RBD-1 is associated with ribosomes and, preferentially, with the 40S ribosomal subunit. Our data suggest that RBD-1 plays a role in structurally coordinating pre-rRNA during ribosome biogenesis and that this function is conserved in all eukaryotes.

Katiki LM et al. (2013) Vet Parasitol "Anthelmintic effect of plant extracts containing condensed and hydrolyzable tannins on Caenorhabditis elegans, and their antioxidant capacity."

Chagas AC, Lindsay DS, Zajac AM, Gonzalez JM, Amarante AF, Ferreira JF, Katiki LM

[Vet Parasitol, 2013]

Although tannin-rich forages are known to increase protein uptake and to reduce gastrointestinal nematode infections in grazing ruminants, most published research involves forages with condensed tannins (CT), while published literature lacks information on the anthelmintic capacity, nutritional benefits, and antioxidant capacity of alternative forages containing hydrolyzable tannins (HT). We evaluated the anthelmintic activity and the antioxidant capacity of plant extracts containing either mostly CT, mostly HT, or both CT and HT. Extracts were prepared with 70% acetone, lyophilized, redissolved to doses ranging from 1.0mg/mL to 25mg/mL, and tested against adult Caenorhabditis elegans as a test model. The extract concentrations that killed 50% (LC(50)) or 90% (LC(90)) of the nematodes in 24h were determined and compared to the veterinary anthelmintic levamisole (8 mg/mL). Extracts were quantified for CT by the acid butanol assay, for HT (based on gallic acid and ellagic acid) by high-performance liquid chromatography (HPLC) and total phenolics, and for their antioxidant activity by the oxygen radical absorbance capacity (ORAC) assay. Extracts with mostly CT were Lespedeza cuneata, Salix X sepulcralis, and Robinia pseudoacacia. Extracts rich in HT were Acer rubrum, Rosa multiflora, and Quercus alba, while Rhus typhina had both HT and CT. The extracts with the lowest LC(50) and LC(90) concentrations, respectively, in the C. elegans assay were Q. alba (0.75 and 1.06 mg/mL), R. typhina collected in 2007 (0.65 and 2.74 mg/mL), A. rubrum (1.03 and 5.54 mg/mL), and R. multiflora (2.14 and 8.70 mg/mL). At the doses of 20 and 25mg/mL, HT-rich, or both CT- and HT-rich, extracts were significantly more lethal to adult C. elegans than extracts containing only CT. All extracts were high in antioxidant capacity, with ORAC values ranging from 1800 moles to 4651 moles of trolox equivalents/g, but ORAC did not correlate with anthelmintic activity. The total phenolics test had a positive and highly significant (r=0.826, p 0.01) correlation with total hydrolyzable tannins. Plants used in this research are naturalized to the Appalachian edaphoclimatic conditions, but occur in temperate climate areas worldwide. They represent a rich, renewable, and unexplored source of tannins and antioxidants for grazing ruminants, whereas conventional CT-rich forages, such as L. cuneata, may be hard to establish and adapt to areas with temperate climate. Due to their high in vitro anthelmintic activity, antioxidant capacity, and their adaptability to non-arable lands, Q. alba, R. typhina, A. rubrum, and R. multiflora have a high potential to improve the health of grazing animals and must have their anthelmintic effects confirmed in vivo in both sheep and goats.

Ryder EF et al. (1997) International C. elegans Meeting "SENSORY MAP FORMATION IN THE C. ELEGANS NERVOUS SYSTEM."

Kaplan JM, Ryder EF, Mason GE, Burket CT

[International C. elegans Meeting, 1997]

Many sensory systems convey spatial information from the external world to the brain by forming an ordered set of neuronal connections known as a topographic map. We are studying the development of topographic maps formed by two sets of head sensory neurons in C. elegans, the IL1!s (visualized by an unc-5::GFP construct kindly provided by J. Culotti) and the IL2!s (visualized by DiO staining; C. Bargmann, pers. comm.). We conducted genetic screens for mutations affecting the formation of these sensory maps, and isolated several alleles of dig-1 (WBG 14:1; ECWM 1996). Sensory processes of dig-1 animals follow aberrant pathways. Mapping data (Michael Basson, Jim Thomas) indicated that dig-1 maps close to sma-3 on III. The genome consortium identified a large gene (>40 kb) in this region with homology to cell adhesion molecules of the Ig superfamily. Probes to this gene show polymorphisms in two dig-1 alleles. We plan to analyze the dig-1 expression pattern. To isolate more genes involved in the adhesion pathway, we are conducting a dig-1 suppresser screen. In vertebrates, sensory maps are formed through axons following a sequence of partially redundant guidance cues; neuronal activity is also involved. If a similar scheme is followed in C. elegans, then mutations in other genes important in map formation may greatly enhance the dig-1 phenotype, even if they have only weak map phenotypes by themselves. We are investigating this possibility by constructing double mutants with a number of candidate genes involved in guidance or activity. We also plan to perform a dig-1 enhancer screen. In addition, we are constructing animals with the unc-5::GFP construct in the background of cilia mutants that affect activity of IL1 neurons.

Sahu, Surasri N et al. (2009) International Worm Meeting "A High Throughput Approach Towards Vibrio cholerae Pathogenesis in Caenorhabditis elegans."

Cinar, Hediye N, Sahu, Surasri N

[International Worm Meeting, 2009]

Vibrio cholerae (VC), the causative agent of cholera in humans, is responsible for devastating epidemics and pandemics across the world. The major virulence factor underlying the pathogenesis of cholera is cholera toxin (CT). However, CT negative VC non-O1 and non-O139 strains and CT deleted vaccine mutant strains are still capable of causing disease symptoms through mechanisms that are currently unclear. Vibrio cholerae cause lethality, growth retardation and escape behavior in Caenorhabditis elegans via cholera toxin (CT), and toxin co-regulated pili (TCP) independent process (1, 2). Absence of the CT and TCP response in C. elegans model may help to reveal the role of other toxins of VC that might otherwise be masked by these major virulence factors. CVD110, a V.cholerae vaccine strain, lacking several virulence factors such as zonula occludens toxin (zot), accessory toxin (ace), hemolysin (hly A) and cholera toxin A subunit gene (ctx A), showed attenuated killing in C. elegans (3,4). We are conducting microarray experiments to define host immune response genes expressed upon exposure to VC virulence factors. Differential expression profiling of C. elegans exposed to wild type VC versus CVD110 are being done using Affymetrix expression microarrays. Results of these experiments will be presented. (1) Vaitkevicius K. et al. PNAS, 103 (2006) 9280-9285 (2) Cinar HN. et al. 16 th International C. elegans Meeting, 2007 (3) Michalski J. et al. Infection and Immunity 61 (1993) 4462-4468 (4) Cinar HN. et al. Aging Stress and Pathogenesis Meeting, 2008.