WormMine

WS295

Intermine data mining platform for C. elegans and related nematodes

Gene :

WormBase Gene ID  ? WBGene00001545 Gene Name  gcy-20
Sequence Name  ? F21H7.9 Brief Description  gcy-20 encodes a predicted guanylate cyclase.
Organism  Caenorhabditis elegans Automated Description  Predicted to enable adenylate cyclase activity; guanylate cyclase activity; and peptide receptor activity. Predicted to be involved in cGMP biosynthetic process and receptor guanylyl cyclase signaling pathway. Predicted to be located in plasma membrane. Expressed in ASEL; AWCL; AWCR; excretory canal; and excretory gland cell.
Biotype  SO:0001217 Genetic Position  V :9.88529 ±0.004855
Length (nt)  ? 5205
Quick Links:
 
Quick Links:
 

1 Organism

Name Taxon Id
Caenorhabditis elegans 6239

1 Synonyms

Value
WBGene00001545

Genomics

1 Transcripts

WormMine ID Sequence Name Length (nt) Chromosome Location
Transcript:F21H7.9.1 F21H7.9.1 3327   V: 16248583-16253787
 

Other

1 CDSs

WormMine ID Sequence Name Length (nt) Chromosome Location
CDS:F21H7.9 F21H7.9 3327   V: 16248583-16248878

3 RNAi Result

WormBase ID
WBRNAi00045260
WBRNAi00013718
WBRNAi00095446

263 Allele

Public Name
gk963271
WBVar02124497
WBVar02124626
gk963302
WBVar02122682
WBVar02124830
WBVar01905578
gk891326
gk851767
tm10593
gk517675
WBVar00244341
WBVar01976244
WBVar01976245
WBVar02025006
WBVar02025007
WBVar01905658
WBVar01905659
WBVar01905660
WBVar01905661
WBVar01905654
WBVar01905655
WBVar01905656
WBVar01905657
WBVar01905650
WBVar01905651
WBVar01905652
WBVar01905653
WBVar01905646
WBVar01905647

1 Chromosome

WormBase ID Organism Length (nt)
V Caenorhabditis elegans 20924180  

1 Chromosome Location


Feature . Primary Identifier
Start End Strand
WBGene00001545 16248583 16253787 -1

4 Data Sets

Name URL
WormBaseAcedbConverter  
GO Annotation data set  
C. elegans genomic annotations (GFF3 Gene)  
Panther orthologue and paralogue predictions  

1 Downstream Intergenic Region

WormBase ID Name Sequence Name Length (nt) Chromosome Location Organism
intergenic_region_chrV_16248543..16248582   40 V: 16248543-16248582 Caenorhabditis elegans

69 Expression Clusters

Regulated By Treatment Description Algorithm Primary Identifier
  Transcripts that showed significantly increased expression in L1 neural cells comparing to in adult neural cells. DESeq2 (v1.18.1) fold change > 2, P-adj<0.05, using BenjaminiHochberg correction. WBPaper00060811:L1_vs_adult_upregulated_neural
  Transcripts of coding genes that showed significantly decreased expression in muscle. DESeq2 (version 1.24.0). Transcripts with a false-discovery rate adjusted p-value less than 0.05 were considered significantly differentially expressed. WBPaper00062325:muscle_depleted_coding-RNA
  Genes that showed expression levels higher than the corresponding reference sample (embryonic 24hr reference). A Mann-Whitney U test with an empirical background model and FDR correction for multiple testing was used to detect expressed transcripts (Benjamini and Hochberg 1995). Genes and TARs with an FDR <= 0.05 were reported as expressed above background. Authors detected differentially expressed transcripts using a method based on linear models. Genes and TARs were called differentially expressed if the FDR was <= 0.05 and the fold change (FC) >= 2.0. To more strictly correct for potential false-positives resulting from multiple sample comparisons, authors divided individual FDR estimates by the number of samplesor sample comparisons, respectively. This resulted in an adjusted FDR of 1.3 * 0.0001 for expression above background and of 7.4 * 0.0001 for differential expression. Authors called genes selectively enriched in a given tissue if they met the following requirements: (1) enriched expression in a given tissue (FDR <= 0.05 and FC >= 2.0), (2) fold change versus reference among the upper 40% of the positive FC range observed for this gene across all tissues, and (3) fold-change entropy among the lower 40% of the distribution observed for all genes. WBPaper00037950:all-neurons_L1-larva_expressed
adult vs dauer larva Transcripts that showed differential expression in adult vs dauer lava in N2 animals at 20C. N.A. WBPaper00050488:adult_vs_dauer_regulated_N2_20C
  TGF- Dauer pathway adult transcriptional targets. Results obtained by comparing the microarray results of the dauer-constitutive mutants daf-7(e1372), daf-7(m62), and daf-1(m40) with dauer-defective mutants daf-3(mgDf90), daf-5(e1386), and daf-7(e1372);daf-3(mgDf90) double mutants at the permissive temperature, 20C, on the first day of adulthood. SAM WBPaper00031040:TGF-beta_adult_upregulated
  Genes that showed expression levels higher than the corresponding reference sample (embryonic 24hr reference). A Mann-Whitney U test with an empirical background model and FDR correction for multiple testing was used to detect expressed transcripts (Benjamini and Hochberg 1995). Genes and TARs with an FDR <= 0.05 were reported as expressed above background. Authors detected differentially expressed transcripts using a method based on linear models. Genes and TARs were called differentially expressed if the FDR was <= 0.05 and the fold change (FC) >= 2.0. To more strictly correct for potential false-positives resulting from multiple sample comparisons, authors divided individual FDR estimates by the number of samplesor sample comparisons, respectively. This resulted in an adjusted FDR of 1.3 * 0.0001 for expression above background and of 7.4 * 0.0001 for differential expression. Authors called genes selectively enriched in a given tissue if they met the following requirements: (1) enriched expression in a given tissue (FDR <= 0.05 and FC >= 2.0), (2) fold change versus reference among the upper 40% of the positive FC range observed for this gene across all tissues, and (3) fold-change entropy among the lower 40% of the distribution observed for all genes. WBPaper00037950:AVE-neuron_L1-larva_expressed
Osmotic stress Transcripts that showed significantly altered expression with 500 mM salt (NaCl) vs 100 mM salt when food was present DESeq(version 1.10.1), FDR < 0.05. WBPaper00050726:OsmoticStress_regulated_Food
  Neuronally enriched transcripts according to a comparison of neuronal nuclei IP samples to total nuclei using isolation of nuclei from tagged specific cell types (INTACT) technology. DESEQ2, fold change > 2 and FDR < 0.01. WBPaper00062103:neuron_enriched
Osmotic stress Transcripts that showed significantly altered expression with 500 mM salt (NaCl) vs 100 mM salt when no food was present DESeq(version 1.10.1), FDR < 0.05. WBPaper00050726:OsmoticStress_regulated_NoFood
  Genes that showed expression levels higher than the corresponding reference sample (embryonic 24hr reference). A Mann-Whitney U test with an empirical background model and FDR correction for multiple testing was used to detect expressed transcripts (Benjamini and Hochberg 1995). Genes and TARs with an FDR <= 0.05 were reported as expressed above background. Authors detected differentially expressed transcripts using a method based on linear models. Genes and TARs were called differentially expressed if the FDR was <= 0.05 and the fold change (FC) >= 2.0. To more strictly correct for potential false-positives resulting from multiple sample comparisons, authors divided individual FDR estimates by the number of samplesor sample comparisons, respectively. This resulted in an adjusted FDR of 1.3 * 0.0001 for expression above background and of 7.4 * 0.0001 for differential expression. Authors called genes selectively enriched in a given tissue if they met the following requirements: (1) enriched expression in a given tissue (FDR <= 0.05 and FC >= 2.0), (2) fold change versus reference among the upper 40% of the positive FC range observed for this gene across all tissues, and (3) fold-change entropy among the lower 40% of the distribution observed for all genes. WBPaper00037950:bodywall-muscle_L1-larva_expressed
  Transcripts that showed significantly increased expression in sin-3(tm1276) comparing to in N2. DESeq2, fold change > 2, p-value < 0.01. WBPaper00061203:sin-3(tm1276)_upregulated
  Transcripts that showed significantly decreased expression in sin-3(tm1276) comparing to in N2 at early embryo when there were only 3 -5 eggs in the adult. DESeq2, fold change > 2, adjusted p-value < 0.01 WBPaper00058598:sin-3(tm1276)_downregulated
  Genes that showed expression levels higher than the corresponding reference sample (L2 all cell reference). A Mann-Whitney U test with an empirical background model and FDR correction for multiple testing was used to detect expressed transcripts (Benjamini and Hochberg 1995). Genes and TARs with an FDR <= 0.05 were reported as expressed above background. Authors detected differentially expressed transcripts using a method based on linear models. Genes and TARs were called differentially expressed if the FDR was <= 0.05 and the fold change (FC) >= 2.0. To more strictly correct for potential false-positives resulting from multiple sample comparisons, authors divided individual FDR estimates by the number of samplesor sample comparisons, respectively. This resulted in an adjusted FDR of 1.3 * 0.0001 for expression above background and of 7.4 * 0.0001 for differential expression. Authors called genes selectively enriched in a given tissue if they met the following requirements: (1) enriched expression in a given tissue (FDR <= 0.05 and FC >= 2.0), (2) fold change versus reference among the upper 40% of the positive FC range observed for this gene across all tissues, and (3) fold-change entropy among the lower 40% of the distribution observed for all genes. WBPaper00037950:all-neurons_L2-larva_expressed
  Transcripts that showed significantly decreased expression in strain GC1459 containing daf-18(ok480) comparing to control strain GC1171. edgeR, p-value < 0.05, fold change > 2. WBPaper00061699:daf-18(ok480)_downregulated
  Genes that showed expression levels higher than the corresponding reference sample (L2 all cell reference). A Mann-Whitney U test with an empirical background model and FDR correction for multiple testing was used to detect expressed transcripts (Benjamini and Hochberg 1995). Genes and TARs with an FDR <= 0.05 were reported as expressed above background. Authors detected differentially expressed transcripts using a method based on linear models. Genes and TARs were called differentially expressed if the FDR was <= 0.05 and the fold change (FC) >= 2.0. To more strictly correct for potential false-positives resulting from multiple sample comparisons, authors divided individual FDR estimates by the number of samplesor sample comparisons, respectively. This resulted in an adjusted FDR of 1.3 * 0.0001 for expression above background and of 7.4 * 0.0001 for differential expression. Authors called genes selectively enriched in a given tissue if they met the following requirements: (1) enriched expression in a given tissue (FDR <= 0.05 and FC >= 2.0), (2) fold change versus reference among the upper 40% of the positive FC range observed for this gene across all tissues, and (3) fold-change entropy among the lower 40% of the distribution observed for all genes. WBPaper00037950:coelomocytes_L2-larva_expressed
  Genes that showed expression levels higher than the corresponding reference sample (L2 all cell reference). A Mann-Whitney U test with an empirical background model and FDR correction for multiple testing was used to detect expressed transcripts (Benjamini and Hochberg 1995). Genes and TARs with an FDR <= 0.05 were reported as expressed above background. Authors detected differentially expressed transcripts using a method based on linear models. Genes and TARs were called differentially expressed if the FDR was <= 0.05 and the fold change (FC) >= 2.0. To more strictly correct for potential false-positives resulting from multiple sample comparisons, authors divided individual FDR estimates by the number of samplesor sample comparisons, respectively. This resulted in an adjusted FDR of 1.3 * 0.0001 for expression above background and of 7.4 * 0.0001 for differential expression. Authors called genes selectively enriched in a given tissue if they met the following requirements: (1) enriched expression in a given tissue (FDR <= 0.05 and FC >= 2.0), (2) fold change versus reference among the upper 40% of the positive FC range observed for this gene across all tissues, and (3) fold-change entropy among the lower 40% of the distribution observed for all genes. WBPaper00037950:excretory-cell_L2-larva_expressed
  Genes that showed expression levels higher than the corresponding reference sample (L2 all cell reference). A Mann-Whitney U test with an empirical background model and FDR correction for multiple testing was used to detect expressed transcripts (Benjamini and Hochberg 1995). Genes and TARs with an FDR <= 0.05 were reported as expressed above background. Authors detected differentially expressed transcripts using a method based on linear models. Genes and TARs were called differentially expressed if the FDR was <= 0.05 and the fold change (FC) >= 2.0. To more strictly correct for potential false-positives resulting from multiple sample comparisons, authors divided individual FDR estimates by the number of samplesor sample comparisons, respectively. This resulted in an adjusted FDR of 1.3 * 0.0001 for expression above background and of 7.4 * 0.0001 for differential expression. Authors called genes selectively enriched in a given tissue if they met the following requirements: (1) enriched expression in a given tissue (FDR <= 0.05 and FC >= 2.0), (2) fold change versus reference among the upper 40% of the positive FC range observed for this gene across all tissues, and (3) fold-change entropy among the lower 40% of the distribution observed for all genes. WBPaper00037950:GABAergic-motor-neurons_L2-larva_expressed
  Genes that showed expression levels higher than the corresponding reference sample (L2 all cell reference). A Mann-Whitney U test with an empirical background model and FDR correction for multiple testing was used to detect expressed transcripts (Benjamini and Hochberg 1995). Genes and TARs with an FDR <= 0.05 were reported as expressed above background. Authors detected differentially expressed transcripts using a method based on linear models. Genes and TARs were called differentially expressed if the FDR was <= 0.05 and the fold change (FC) >= 2.0. To more strictly correct for potential false-positives resulting from multiple sample comparisons, authors divided individual FDR estimates by the number of samplesor sample comparisons, respectively. This resulted in an adjusted FDR of 1.3 * 0.0001 for expression above background and of 7.4 * 0.0001 for differential expression. Authors called genes selectively enriched in a given tissue if they met the following requirements: (1) enriched expression in a given tissue (FDR <= 0.05 and FC >= 2.0), (2) fold change versus reference among the upper 40% of the positive FC range observed for this gene across all tissues, and (3) fold-change entropy among the lower 40% of the distribution observed for all genes. WBPaper00037950:glr-1(+)-neurons_L2-larva_expressed
  Genes that showed expression levels higher than the corresponding reference sample (L2 all cell reference). A Mann-Whitney U test with an empirical background model and FDR correction for multiple testing was used to detect expressed transcripts (Benjamini and Hochberg 1995). Genes and TARs with an FDR <= 0.05 were reported as expressed above background. Authors detected differentially expressed transcripts using a method based on linear models. Genes and TARs were called differentially expressed if the FDR was <= 0.05 and the fold change (FC) >= 2.0. To more strictly correct for potential false-positives resulting from multiple sample comparisons, authors divided individual FDR estimates by the number of samplesor sample comparisons, respectively. This resulted in an adjusted FDR of 1.3 * 0.0001 for expression above background and of 7.4 * 0.0001 for differential expression. Authors called genes selectively enriched in a given tissue if they met the following requirements: (1) enriched expression in a given tissue (FDR <= 0.05 and FC >= 2.0), (2) fold change versus reference among the upper 40% of the positive FC range observed for this gene across all tissues, and (3) fold-change entropy among the lower 40% of the distribution observed for all genes. WBPaper00037950:intestine_L2-larva_expressed
  Transcripts that showed significantly increased expression in hda-2(ok1479) comparing to in N2 animals. DESeq2 (version 1.28.1), FDR < 0.01, fold change > 2. WBPaper00062159:hda-2(ok1479)_upregulated
  Transcripts that showed significantly decreased expression after animals were treated with 100uM Psora and 250uM Allantoin from day 1 to day 3 adult hermaphradite. DESeq2(v1.14.1), fold change > 2, p-value < 0.05 WBPaper00055354:Psora-Allantoin_downregulated
  Transcripts that showed significantly decreased expression after animals were treated with 100uM Rapamycin and 50uM Rifampicin from day 1 to day 3 adult hermaphradite. DESeq2(v1.14.1), fold change > 2, p-value < 0.05 WBPaper00055354:Rapamycin-Rifampicin_downregulated
  Transcripts that showed significantly decreased expression after animals were treated with 50uM Rifampicin and 250uM Allantoin from day 1 to day 3 adult hermaphradite. DESeq2(v1.14.1), fold change > 2, p-value < 0.05 WBPaper00055354:Rifampicin-Allantoin_downregulated
  Transcripts that showed significantly decreased expression in set-2(tm1630) animals at embryo stage, comparing to in N2 animals. DESeq2 (v2.1.8.3) was used to determine DE genes and to generate principal component and scatter plots. DE genes with FDR < 0.05 were analysed using g:Profiler with Bonferroni correction. WBPaper00060014:set-2(tm1630)_downregulated
  Genes regulated by DAF-16, according to whole transcriptome profiling to compare genome-wide regulatory influences of DPY-21 and SET-4 to those of the key transcription factors controlling dauer arrest in eak-7;akt-1 animals, DAF-16 and DAF-12. Authors identified genes differentially expressed between wild-type and eak-7;akt-1 double mutant animals [fold change >= 1.5 and false discovery rate (FDR) < 0.05]. Authors then compared the transcriptomes of eak-7;akt-1 double mutants to those of eak-7;akt-1 animals harboring mutations in dpy-21, set-4, daf-16, or daf-12, and identified genes that are differentially expressed in the opposite direction as in wild-type relative to eak-7;akt-1. Annotated gene expression data output from CuffDiff v2.2.1 was read into R version 3.2.1 for six comparisons: eak-7;akt-1 compared to (1) wild-type, (2) daf-16(mu86);eak-7;akt-1, (3) daf-12;eak-7;akt-1, (4) set-4(n4600);eak-7;akt-1, (5) set-4(dp268);eak-7;akt-1, and (6) dpy-21;eak-7;akt-1. Authors filtered genes by the following criteria: (1) status = OK for wild-type vs. eak-7;akt-1, (2) fold change (FC) >= 1.5 or FC <= 1/1.5 for wild-type vs. eak-7;akt-1 and (3) FDR < 0.05 for at least two separate comparisons. WBPaper00050801:DAF-16_dauer_regulome
  Genes regulated by DPY-21, according to whole transcriptome profiling to compare genome-wide regulatory influences of DPY-21 and SET-4 to those of the key transcription factors controlling dauer arrest in eak-7;akt-1 animals, DAF-16 and DAF-12. Authors identified genes differentially expressed between wild-type and eak-7;akt-1 double mutant animals [fold change >= 1.5 and false discovery rate (FDR) < 0.05]. Authors then compared the transcriptomes of eak-7;akt-1 double mutants to those of eak-7;akt-1 animals harboring mutations in dpy-21, set-4, daf-16, or daf-12, and identified genes that are differentially expressed in the opposite direction as in wild-type relative to eak-7;akt-1. Annotated gene expression data output from CuffDiff v2.2.1 was read into R version 3.2.1 for six comparisons: eak-7;akt-1 compared to (1) wild-type, (2) daf-16(mu86);eak-7;akt-1, (3) daf-12;eak-7;akt-1, (4) set-4(n4600);eak-7;akt-1, (5) set-4(dp268);eak-7;akt-1, and (6) dpy-21;eak-7;akt-1. Authors filtered genes by the following criteria: (1) status = OK for wild-type vs. eak-7;akt-1, (2) fold change (FC) >= 1.5 or FC <= 1/1.5 for wild-type vs. eak-7;akt-1 and (3) FDR < 0.05 for at least two separate comparisons. WBPaper00050801:DPY-21_dauer_regulome
  Genes that showed expression levels higher than the corresponding reference sample (embryonic 24hr reference). A Mann-Whitney U test with an empirical background model and FDR correction for multiple testing was used to detect expressed transcripts (Benjamini and Hochberg 1995). Genes and TARs with an FDR <= 0.05 were reported as expressed above background. Authors detected differentially expressed transcripts using a method based on linear models. Genes and TARs were called differentially expressed if the FDR was <= 0.05 and the fold change (FC) >= 2.0. To more strictly correct for potential false-positives resulting from multiple sample comparisons, authors divided individual FDR estimates by the number of samplesor sample comparisons, respectively. This resulted in an adjusted FDR of 1.3 * 0.0001 for expression above background and of 7.4 * 0.0001 for differential expression. Authors called genes selectively enriched in a given tissue if they met the following requirements: (1) enriched expression in a given tissue (FDR <= 0.05 and FC >= 2.0), (2) fold change versus reference among the upper 40% of the positive FC range observed for this gene across all tissues, and (3) fold-change entropy among the lower 40% of the distribution observed for all genes. WBPaper00037950:coelomocytes_L1-larva_expressed
  Genes found to be regulated by low-copy overexpression of sir-2.1 with p < 0.014. N.A. WBPaper00026929:sir-2.1_overexpression_regulated
  Genes that showed expression levels higher than the corresponding reference sample (embryonic 24hr reference). A Mann-Whitney U test with an empirical background model and FDR correction for multiple testing was used to detect expressed transcripts (Benjamini and Hochberg 1995). Genes and TARs with an FDR <= 0.05 were reported as expressed above background. Authors detected differentially expressed transcripts using a method based on linear models. Genes and TARs were called differentially expressed if the FDR was <= 0.05 and the fold change (FC) >= 2.0. To more strictly correct for potential false-positives resulting from multiple sample comparisons, authors divided individual FDR estimates by the number of samplesor sample comparisons, respectively. This resulted in an adjusted FDR of 1.3 * 0.0001 for expression above background and of 7.4 * 0.0001 for differential expression. Authors called genes selectively enriched in a given tissue if they met the following requirements: (1) enriched expression in a given tissue (FDR <= 0.05 and FC >= 2.0), (2) fold change versus reference among the upper 40% of the positive FC range observed for this gene across all tissues, and (3) fold-change entropy among the lower 40% of the distribution observed for all genes. WBPaper00037950:hypodermis_L1-larva_expressed
  Transcripts that showed significantly increased expression in lin-22(ot269) comparing to in N2 at L3 larva. Differences in gene expression were then calculated using the negative binomial test in the DESeq package (FDR = 0.1). WBPaper00053295:lin-22(ot269)_upregulated

5 Expression Patterns

Remark Reporter Gene Primary Identifier Pattern Subcellular Localization
    Expr4537 Expressed in ASEL, AWCL/R (faint) excretory gland and canal cells.  
    Expr2011984 Single cell embryonic expression. Only cell types with an expression fraction of greater 0.2 of the maximum expressed fraction are labeled (Full data can be downloaded from http://caltech.wormbase.org/pub/wormbase/datasets-published/packer2019/). The colors represent the broad cell class to which the cell type has been assigned. The size of the point is proportional to the log2 of the numbers of cells in the dataset of that cell type. Interactive visualizations are available as a web app (https://cello.shinyapps.io/celegans/) and can also be installed as an R package (https://github.com/qinzhu/VisCello.celegans).  
    Expr1149191 Developmental gene expression time-course. Raw data can be downloaded from ftp://caltech.wormbase.org/pub/wormbase/datasets-published/hashimshony2015  
    Expr1024131 Developmental gene expression time-course. Raw data can be downloaded from ftp://caltech.wormbase.org/pub/wormbase/datasets-published/levin2012  
    Expr2030222 Single cell embryonic expression. Only cell types with an expression fraction of greater 0.2 of the maximum expressed fraction are labeled (Full data can be downloaded from http://caltech.wormbase.org/pub/wormbase/datasets-published/packer2019/). The colors represent the broad cell class to which the cell type has been assigned. The size of the point is proportional to the log2 of the numbers of cells in the dataset of that cell type. Interactive visualizations are available as a web app (https://cello.shinyapps.io/celegans/) and can also be installed as an R package (https://github.com/qinzhu/VisCello.celegans).  

17 GO Annotation

Annotation Extension Qualifier
  involved_in
  involved_in
  involved_in
  involved_in
  enables
  involved_in
  enables
  enables
  located_in
  located_in
  involved_in
  located_in
  enables
  enables
  enables
  enables
  enables

19 Homologues

Type
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue
orthologue

1 Locations


Feature . Primary Identifier
Start End Strand
WBGene00001545 16248583 16253787 -1

17 Ontology Annotations

Annotation Extension Qualifier
  involved_in
  involved_in
  involved_in
  involved_in
  enables
  involved_in
  enables
  enables
  located_in
  located_in
  involved_in
  located_in
  enables
  enables
  enables
  enables
  enables

0 Regulates Expr Cluster

1 Sequence

Length
5205

1 Sequence Ontology Term

Identifier Name Description
gene  

4 Strains

WormBase ID
WBStrain00029400
WBStrain00032620
WBStrain00037302
WBStrain00037343

1 Upstream Intergenic Region

WormBase ID Name Sequence Name Length (nt) Chromosome Location Organism
intergenic_region_chrV_16253788..16253906   119 V: 16253788-16253906 Caenorhabditis elegans