Ward S et al. (1975) Worm Breeder's Gazette "a simple device for counting worms."

Schubarth R, Ward S

[Worm Breeder's Gazette, 1975]

In genetic crosses and in experiments measuring the number of progeny produced by a worm, the counting of progeny is tedious. It is often important to kill off or remove all of one generation before they reach maturity in order to prevent a second generation from confusing results. We have found that a miniature soldering iron can be used for killing individual animals on a petri plate. The killing is reliable and fast if the tip is cleaned of roasted worm periodically. If the soldering iron is connected to a counting circuit, such as those used in resistance type bacterial plaque counters, the counts are recorded automatically. The schematic of a simple counting circuit we have built is diagrammed below. The second terminal is connected to the agar surface by an alligator clip. The standard copper tip on the iron can be sharpened for use, but we find it more convenient to use the fine pointed tip of a dissecting needle fastened to the soldering iron with a brass sleeve. The whole system can be purchased and assembled for about $60. [See Figure 1]

Kennedy MW et al. (1995) Biochemistry "The ABA-1 allergen of the parasitic nematode Ascaris suum: fatty acid and retinoid binding function and structural characterization."

Cooper A, Price NC, McCruden AB, Brass A, Kelly SM, Kennedy MW

[Biochemistry, 1995]

We report here on the structure and function of the ABA-1 allergen protein of the parasitic nematode Ascaris, the first nematode allergen to be characterized in detail. Using the fluorescent fatty acid analog 11-(((5-(dimethylamino)-1-naphthalenyl)sulfonyl)amino)undecanoic acid (DAUDA), it was demonstrated that ABA-1 is a fatty acid binding protein (FABP) with a high affinity for the fluorescent analog (8.8 x 10(-8) M) and for oleic acid in competition experiments (1.3 x 10(-8) M), with a single binding site for ligand per monomer unit. Blue-shifting of fluorescence emission of DAUDA upon binding was unprecedented in degree among FABPs, being equivalent to that occurring in cyclohexane. A similarly blue-shifted spectrum was obtained with a probe in which the fluorophore was bound to the alpha carbon of a fatty acid, indicating that the carboxylate group of bound fatty acids is probably not exposed to solvent. In competition experiments and by observation of changes in their intrinsic fluorescence, retinol and retinoic acid were also found to bind in the fatty acid binding site. Circular dichroism (CD) of the ABA-1 protein revealed a high alpha-helix content (59%) which was consistent with the four-helix structure for the protein predicted from sequence algorithms. Fluorescence measurements showed that the single, highly conserved tryptophan residue is deeply buried in an unusually apolar environment and that this was unaffected by ligand binding. DSC studies of thermal stability indicate that unfolding of the ABA-1 dimer is cooperative and biphasic (Tm approximately 71 and 89 degrees C), suggesting a two-domain thermal unfolding process, again consistent with the predicted structure. Only the folding of the high-temperature domain is reversible on cooling. DSC confirmed the gel filtration analysis, which indicated that ABA-1 forms a dimer. Aside from being the first nematode allergen for which structure or function has been elucidated, ABA-1 provides a highly manipulable model for investigation of the interaction between hydrophobic ligands and alpha-helical proteins.

Kennedy MW et al. (1997) J Biol Chem "The Ov20 protein of the parasitic nematode Onchocerca volvulus. A structurally novel class of small helix-rich retinol-binding proteins."

Cooper A, Brass A, Garside LH, Kelly SM, Bradley JE, McDermott L, Goodrick LE, Price NC, Kennedy MW

[J Biol Chem, 1997]

Ov20 is a major antigen of the parasitic nematode Onchocerca volvulus, the causative agent of river blindness in humans, and the protein is secreted into the tissue occupied by the parasite. DNA encoding Ov20 was isolated, and the protein was expressed in Escherichia coli. Fluorescence-based ligand binding assays show that the protein contains a high affinity binding site for retinol, fluorescent fatty acids (11-((5-dimethylaminonaphthalene-1-sulfonyl)amino)undecanoic acid, dansyl-DL-alpha-aminocaprylic acid, and parinaric acid) and, by competition, oleic and arachidonic acids, but not cholesterol. The fluorescence emission of dansylated fatty acids is significantly blue-shifted upon binding in comparison to similarly sized beta-sheet-rich mammalian retinol- and fatty acid-binding proteins. Secondary structure prediction algorithms indicate that a alpha-helix predominates in Ov20, possibly in a coiled coil motif, with no evidence of beta structures, and this was confirmed by circular dichroism. The protein is highly stable in solution, requiring temperatures in excess of 90 degrees C or high denaturant concentrations for unfolding. Ov20 therefore represents a novel class of small retinol-binding protein, which appears to be confined to nematodes. The retinol binding activity of Ov20 could possibly contribute to the eye defects associated with onchocerciasis and, because there is no counterpart in mammals, represents a strategic target for chemotherapy.

McDermott L et al. (2001) Biochemistry "Mutagenic and chemical modification of the ABA-1 allergen of the nematode Ascaris: consequences for structure and lipid binding properties."

Kelly SM, Price NC, Kennedy MW, Brass A, McDermott L, Cooper A, Moore J

[Biochemistry, 2001]

The polyprotein allergens/antigens of nematodes (NPAs) are the only lipid binding proteins known to be produced as polyproteins. Cleavage of the large polyprotein precursors at regularly spaced proteinase cleavage sites produces 10 or 11 individual protein units of approximately 15 kDa. The sequences of these units are highly diverse within and between species, but there are five absolutely or strongly conserved amino acid positions (Trp15, Gln20, Leu42, Cys64, and Cys120). We have tested the role of these signature amino acids by mutational or chemical alteration of the ABA-1 protein of Ascaris, and examined the resulting modified proteins for perturbations of their lipid binding activities and structural integrity. Substitution of Trp15 and Gln20 both affect the stability of the protein in terms of resistance to thermal or chemical denaturation, but the ligand binding function is unaffected. Mutation of Leu42, however, disrupts both the protein's structural stability and functional integrity, as does chemical disruption of the disulfide bridge formed between Cys64 and Cys120. We also find that the C-terminal, but not the N-terminal, half of the protein binds fatty acids, indicating that the binding site may be confined to this part of the protein. This also supports the idea that the NPA units are themselves derived from an ancient duplication event, and that they may comprise two functionally distinct domains.

Quartey MO et al. (2021) Sci Rep "The A(1-38) peptide is a negative regulator of the A(1-42) peptide implicated in Alzheimer disease progression."

Pennington PR, Heistad RM, Nyarko JNK, Barnes JR, Bolanos MAC, Parsons MP, Knudsen KJ, De Carvalho CE, Leary SC, Mousseau DD, Buttigieg J, Maley JM, Quartey MO

[Sci Rep, 2021]

The pool of -Amyloid (A) length variants detected in preclinical and clinical Alzheimer disease (AD) samples suggests a diversity of roles for A peptides. We examined how a naturally occurring variant, e.g. A(1-38), interacts with the AD-related variant, A(1-42), and the predominant physiological variant, A(1-40). Atomic force microscopy, Thioflavin T fluorescence, circular dichroism, dynamic light scattering, and surface plasmon resonance reveal that A(1-38) interacts differently with A(1-40) and A(1-42) and, in general, A(1-38) interferes with the conversion of A(1-42) to a -sheet-rich aggregate. Functionally, A(1-38) reverses the negative impact of A(1-42) on long-term potentiation in acute hippocampal slices and on membrane conductance in primary neurons, and mitigates an A(1-42) phenotype in Caenorhabditis elegans. A(1-38) also reverses any loss of MTT conversion induced by A(1-40) and A(1-42) in HT-22 hippocampal neurons and APOE 4-positive human fibroblasts, although the combination of A(1-38) and A(1-42) inhibits MTT conversion in APOE 4-negative fibroblasts. A greater ratio of soluble A(1-42)/A(1-38) [and A(1-42)/A(1-40)] in autopsied brain extracts correlates with an earlier age-at-death in males (but not females) with a diagnosis of AD. These results suggest that A(1-38) is capable of physically counteracting, potentially in a sex-dependent manner, the neuropathological effects of the AD-relevant A(1-42).

Danielle Thierry-Mieg et al. (2003) Worm Breeder's Gazette "www.wormgenes.org , a new gene centered database"

Vahan Simonyan, Michel Potdevin, Mark Sienkiewicz, Yuji KOHARA, Jean Thierry-Mieg, Danielle Thierry-Mieg, Tadasu SHIN-I

[Worm Breeder's Gazette, 2003]

Wormgenes is a new resource for C.elegans offering a detailed summary about each gene and a powerful query system.

Tangrodchanapong T et al. (2020) Front Pharmacol "Frondoside A Attenuates Amyloid- Proteotoxicity in Transgenic Caenorhabditis elegans by Suppressing Its Formation."

Tangrodchanapong T, Sobhon P, Meemon K

[Front Pharmacol, 2020]

Oligomeric assembly of Amyloid- (A) is the main toxic species that contribute to early cognitive impairment in Alzheimer's patients. Therefore, drugs that reduce the formation of A oligomers could halt the disease progression. In this study, by using transgenic <i>Caenorhabditis elegans</i> model of Alzheimer's disease, we investigated the effects of frondoside A, a well-known sea cucumber <i>Cucumaria frondosa</i> saponin with anti-cancer activity, on A aggregation and proteotoxicity. The results showed that frondoside A at a low concentration of 1 M significantly delayed the worm paralysis caused by A aggregation as compared with control group. In addition, the number of A plaque deposits in transgenic worm tissues was significantly decreased. Frondoside A was more effective in these activities than ginsenoside-Rg3, a comparable ginseng saponin. Immunoblot analysis revealed that the level of small oligomers as well as various high molecular weights of A species in the transgenic <i>C. elegans</i> were significantly reduced upon treatment with frondoside A, whereas the level of A monomers was not altered. This suggested that frondoside A may primarily reduce the level of small oligomeric forms, the most toxic species of A. Frondoside A also protected the worms from oxidative stress and rescued chemotaxis dysfunction in a transgenic strain whose neurons express A. Taken together, these data suggested that low dose of frondoside A could protect against A-induced toxicity by primarily suppressing the formation of A oligomers. Thus, the molecular mechanism of how frondoside A exerts its anti-A aggregation should be studied and elucidated in the future.

Hodgkin JA (1998) International Journal of Developmental Biology "Seven types of pleiotropy."

Hodgkin JA

[International Journal of Developmental Biology, 1998]

Pleiotropy , a situation in which a single gene influences multiple phenotypic tra its, can arise in a variety of ways. This paper discusses possible underlying mechanisms and proposes a classification of the various phenomena involved.

Tuck S (2011) Curr Biol "Extracellular vesicles: budding regulated by a phosphatidylethanolamine translocase."

Tuck S

[Curr Biol, 2011]

Recent work on a Caenorhabditis elegans transmembrane ATPase reveals a central role for the aminophospholipid phosphatidylethanolamine in the production of a class of extracellular vesicles.

Viney ME et al. (2004) Naturwissenschaften "Is dauer pheromone of Caenorhabditis elegans really a pheromone?"

Viney ME, Franks NR

[Naturwissenschaften, 2004]

Animals respond to signals and cues in their environment. The difference between a signal (e.g. a pheromone) and a cue (e.g. a waste product) is that the information content of a signal is subject to natural selection, whereas that of a cue is not. The model free-living nematode Caenorhabditis elegans forms an alternative developmental morph (the dauer larva) in response to a so-called 'dauer pheromone', produced by all worms. We suggest that the production of 'dauer pheromone' has no fitness advantage for an individual worm and therefore we propose that 'dauer pheromone' is not a signal, but a cue. Thus, it should not be called a pheromone.