Okimoto R et al. (1992) Genetics "The mitochondrial genomes of two nematodes, Caenorhabditis elegans and Ascaris suum."

Okimoto R, Wolstenholme DR, Macfarlane JL, Clary DO

[Genetics, 1992]

The nucleotide sequences of the mitochondrial DNA (mtDNA) molecules of two nematodes, Caenorhabditis elegans [13,794 nucleotide pairs (ntp)], and Ascaris suum (14,284 ntp) are presented and compared. Each molecule contains the genes for two ribosomal RNAs (s-rRNA and l-rRNA), 22 transfer RNAs (tRNAs) and 12 proteins, all of which are transcribed in the same direction. The protein genes are the same as 12 of the 13 protein genes found in other metazoan mtDNAs: Cyt b, cytochrome b; COI-III, cytochrome c oxidase subunits I-III; ATPase6, Fo ATPase subunit 6; ND1-6 and 4L, NADH dehydrogenase subunits 1-6 and 4L: a gene for ATPase subunit 8, common to other metazoan mtDNAs, has not been identified in nematode mtDNAs. The C. elegans and A. suum mtDNA molecules both include an apparently noncoding sequence that contains runs of AT dinucleotides, and direct and inverted repeats (the AT region: 466 and 886 ntp, respectively). A second, apparently noncoding sequence in the C. elegans and A. suum mtDNA molecules (109 and 117 ntp, respectively) includes a single, hairpin-forming structure. There are only 38 and 89 other intergenic nucleotides in the C. elegans and A. suum mtDNAs, and no introns. Gene arrangements are identical in the C. elegans and A. suum mtDNA molecules except that the AT regions have different relative locations. However, the arrangement of genes in the two nematode mtDNAs differs extensively from gene arrangements in all other sequenced metazoan mtDNAs. Unusual features regarding nematode mitochondrial tRNA genes and mitochondrial protein gene initiation codons, previously described by us, are reviewed. In the C. elegans and A. suum mt-genetic codes, AGA and AGG specify serine, TGA specifies tryptophan and ATA specifies methionine. From considerations of amino acid and nucleotide sequence similarities it appears likely that the C. elegans and A. suum ancestral lines diverged close to the time of divergence of the cow and human ancestral lines, about 80 million years ago.

Wolstenholme DR et al. (1987) Proc Natl Acad Sci U S A "Bizarre tRNAs inferred from DNA sequences of mitochondrial genomes of nematode worms."

Macfarlane JL, Okimoto R, Clary DO, Wahleithner JA, Wolstenholme DR

[Proc Natl Acad Sci U S A, 1987]

The complete nucleotide sequence of the mitochondrial DNA (mtDNA) molecule of the parasitic nematode worm Ascaris suum has been determined. This molecule lacks genes for tRNAs of the standard form. Instead, 21 sequences are found that can be folded into structures that resemble tRNAs in which the T psi C arm and variable loop are missing and replaced with a single loop of between 4 and 12 nucleotides. Considerations of various properties of these sequences, including the number, predicted anticodons, conserved nucleotides, direction of transcription, base composition, and relative gene arrangements are consistent with the interpretation that they are genes for a different sort of tRNA. Transfer RNA genes with a similar potential secondary structure are found in mtDNA of the free-living nematode Caenorhabditis elegans, suggesting that this unusual form of tRNA is used by all nematode mitochondria.

Ashrafi K (2022) Cell Host Microbe "Better living through communal eating."

Ashrafi K

[Cell Host Microbe, 2022]

Caenorhabditis elegans do not grow on either Staphylococcus saprophyticus or heat-killed Escherichia coli, but do so when exposed to both. In this issue of Cell Host & Microbe, Geng and colleagues have identified E.coli-derived signals as well as the host's neural and innate immunity pathways that promote digestion of S.saprophyticus.

Doitsidou M et al. (2008) Nat Methods "Automated screening for mutants affecting dopaminergic-neuron specification in C. elegans."

Flames N, Lee AC, Boyanov A, Doitsidou M, Hobert O

[Nat Methods, 2008]

We describe an automated method to isolate mutant Caenorhabditis elegans that do not appropriately execute cellular differentiation programs. We used a fluorescence-activated sorting mechanism implemented in the COPAS Biosort machine to isolate mutants with subtle alterations in the cellular specificity of GFP expression. This methodology is considerably more efficient than comparable manual screens and enabled us to isolate mutants in which dopamine neurons do not differentiate appropriately.

Soh CT et al. (1966) Kisaengchunghak Chapchi "Clinical manifestation of Brugia malayi infection in Korea."

Soh CT, Lee KT, Im SW, Lee JH

[Kisaengchunghak Chapchi, 1966]

The clinical manifestations in filarial infection were examined during 1965-1966 from the known endemic areas: Yongju, a mountainous inland area and Cheju-Do, an island. 1. All the microfilaria which were found during the survey were Brugia malayi. 2. The principal symptom was cuticular hypertrophy (elephantiasis). It was found in 4 cases from Yongju among 707 villagers, 84 cases from Cheju-Do among 2,376 villagers. 3. Four microfilaremia cases (4.5%) were found among a total of 88 cases of elephantiasis. 4. In Cheju-Do, the higher incidence of elephantiasis was observed among people over 20 years old and the females showed much higher incidence than males (30 males and 54 females). 5. The cuticular hypertrophic changes (elephantiasis) appeared more often in the lower extremities(77%) than in the upper part of the body, and in the right side than in the left.

Chalfie M (1982) Cold Spring Harb Symp Quant Biol "Microtubule structure in Caenorhabditis elegans neurons."

Chalfie M

[Cold Spring Harb Symp Quant Biol, 1982]

Microtubules (MTs) are ubiquitous components of neuronal processes, and although they have been implicated in neurite outgrowth, shape maintenance, axonal transport, and sensory transduction, their function remains unclear. The MTs in the neurons of the nematode Caenorhabditis elegans have unusual structures that permit a comparative approach to the relationship of microtubule structure and function. A set of six touch-receptor neurons (the microtubule cells) contain prominent arrays of large MTs. These MTs have more protofilaments than do MTs in other neurons (15 as opposed to 11), and they respond differently to antimicrotubule drugs, fixation protocols, temperature, and mutation. Studies of C. elegans neurotubules suggest that most MT functions do not require long, continuous MTs or MTs with a specific number of protofilaments. Some functions, however, such as the sensory transduction of the microtubule cells, do require a specific microtubule substructure. A review of these data is presented in this

Iannacone MJ et al. (2016) Curr Biol "Sleep: How Many Switches Does It Take To Turn Off the Lights?"

Raizen DM, Iannacone MJ

[Curr Biol, 2016]

Sleeping animals do not move or feed and are less responsive. In Caenorhabditis elegans, a single neuron triggers sleep. A recent study shows that the neuron releases several neuropeptides - each with distinct sleep behavioral effects - to promote the collection of behaviors that is sleep.

Al-Sheikh U et al. (2021) Neuron "Mechanosensation: Alpha-7 nAChR transduces sound signals in earless C.elegans."

Al-Sheikh U, Kang L

[Neuron, 2021]

How do organisms without specialized auditory systems perceive and transduce sound? In this issue of Neuron, Iliff etal. (2021) investigate the functional mechanism of airborne sound sensation in Caenorhabditis elegans and highlight the crucial role of alpha-7 nicotinic acetylcholine receptor subunits in mechanotransduction.

Kohra S et al. (2002) Journal of Health Science "A rapid respiratory toxicity test using Caenorhabditis elegans with an oxygen electrode system."

Takao Y, Ueda K, Tominaga N, Arizono K, Ishibashi Y, Nagae M, Kohra S

[Journal of Health Science, 2002]

We describe a novel approach to evaluating the respiratory toxicity of chemicals in the free-living nematode Caenorhabditis elegans. Using DOX-96KT, a general purpose, multi-channel dissolved oxygen (DO) measuring system, we measured the DO concentration in culture media containing C. elegans exposed to chemicals to assay for respiratory toxicity. The current value, which is an index of the dissolved oxygen concentration in culture media, was measured every 10 sec for 30 min at 24degreeC. We focused on the respiration levels of the exposed worms between 500 and 1800 sec. This method produces results that are similar to the computer tracking system measuring behavioral toxicity. Since it can do multiple dilution series tests at a given time, it is useful for concentration-activity correlation studies. This novel technique is not only an alternative to the computer tracking system for measuring behavioral toxicity but also a rapid sublethal toxicity test for chemical hazard assessment.

Ardiel EL et al. (2009) Adv Genet "C. elegans: social interactions in a "nonsocial" animal."

Rankin CH, Ardiel EL

[Adv Genet, 2009]

As self-fertilizing nematodes, Caenorhabditis elegans do not normally come to mind when one thinks of social animals. However, their reproductive mode is optimized for rapid population growth, and although they do not form structured societies, conspecifics are an important source of sensory input. A pheromone signal underlies multiple complex behaviors, including diapause, male-mating, and aggregation. The use of C. elegans in sociogenetics research allows for the analysis of social interactions at the level of genes, circuits, and behaviors. This chapter describes natural polymorphisms in mab-23, plg-1, npr-1, and glb-5 as they relate to two C. elegans social behaviors: male-mating and aggregation.