Ozcelik A et al. (2016) Small "Acoustofluidic Rotational Manipulation of Cells and Organisms Using Oscillating Solid Structures."

Kaynak M, Nama N, McReynolds MR, Huang TJ, Hanna-Rose W, Ozcelik A, Huang PH

[Small, 2016]

A polydimethylsiloxane microchannel featuring sidewall sharp-edge structures and bare channels, and a piezoelement transducer is attached to a thin glass slide. When an external acoustic field is applied to the microchannel, the oscillation of the sharp-edge structures and the thin glass slide generate acoustic streaming flows which in turn rotate single cells and C. elegans in-plane and out-of-plane.

Ohkubo J et al. (2010) J Theor Biol "Long-tail behavior in locomotion of Caenorhabditis elegans."

Iino Y, Yoshida K, Masuda N, Ohkubo J

[J Theor Biol, 2010]

The locomotion of Caenorhabditis elegans exhibits complex patterns. In particular, the worm combines mildly curved runs and sharp turns to steer its course. Both runs and sharp turns of various types are important components of taxis behavior. The statistics of sharp turns have been intensively studied. However, there have been few studies on runs, except for those on klinotaxis (also called weathervane mechanism), in which the worm gradually curves toward the direction with a high concentration of chemicals; this phenomenon was discovered recently. We analyzed the data of runs by excluding sharp turns. We show that the curving rate obeys long-tail distributions, which implies that large curving rates are relatively frequent. This result holds true for locomotion in environments both with and without a gradient of NaCl concentration; it is independent of klinotaxis. We propose a phenomenological computational model on the basis of a random walk with multiplicative noise. The assumption of multiplicative noise posits that the fluctuation of the force is proportional to the force exerted. The model reproduces the long-tail property present in the experimental data.

Schmidt GD et al. (1972) Proc. Helminthological Society of Washington "Nematode parasites of Oceanica. XVIII. C. avicola sp. n. (Rhabditidae) found in a bird from Taiwan."

Schmidt GD, Kuntz RE

[Proc. Helminthological Society of Washington, 1972]

Caenorhabditis avicola sp. n. is described from one male and three female nematodes from the intestine of a plumbeous water redstart, Rhyacornis fuliginosus (Passeriformes, Turdidae), from Taiwan. It is characterized by the extension of the anterior margins of the peloderan bursa into sharp points, giving the male posterior end an arrowheadlike shape in ventral view, and by the spicules, which are 95 u long. It is postulated that the worms were pseudoparasites, possibly symbionts of an insect ingested by the bird.

Aiyar S (1983) Southeast Asian J Trop Med Public Health "Attempts to infect experimentally immunosuppressed iris monkeys (Macaca iris) with Brugia malayi."

Aiyar S

[Southeast Asian J Trop Med Public Health, 1983]

Iris monkeys resistant to repeated infections with B. malayi were subjected to immunosuppression by treatment with cortisone. Degree of immunosuppression was measured by: (a) blood counts, (b) lymphocyte transformation to mitogens and (c) immunofluorescent antibody to microfilarial antigens. Attempts were made to infect such immunosuppressed animals with B. malayi. No microfilariae were detected in the blood of any of the Iris monkeys during the 6 months of study. There was a sharp drop in the percentages of lymphocytes, but a rise in neutrophil counts during the first week of cortisone administration. Treatment with cortisone did not alter the antibody titres. The significance of this line of approach in the understanding of filarial resistance is discussed.

Borgonie G et al. (1996) Fundamental and Applied Nematology "Effect of a nematicidal Bacillus thuringiensis strain on free-living nematodes. 3. Characterization of the intoxication process."

De Waele D, Arnaut G, Coomans AV, Leyns F, Claeys M, Borgonie G

[Fundamental and Applied Nematology, 1996]

The toxicity of Bacillus thuringiensis is temperature sensitive. Incubation of Caenorhabditis elegans with nematicidal B. thuringiensis strains at 16, 20, and 25 degrees C shows that toxicity decreases as temperature declines. At 16 degrees C, toxicity is completely lost, while it is maximal at 25 degrees C. Toxicity is pH sensitive and is significantly reduced when nematodes are incubated with the weak bases NH4Cl, chloroquine, acridine orange, methyl red, and neutral red. Based on these results, we proposed the hypothesis that the nematicidal factor is effectively internalized into the intestinal cells, a sharp deviation from the insecticidal B. thuringiensis toxins acting at the level of the brush border membrane. Although the absence of purified toxins prevents a more definitive elucidation of the mode of action, the results of this third and final part of this series of publications convincingly indicate that nematicidal B. thuringiensis do not hold the same promise as a biological control agent as the insecticidal B. thuringiensis strains.

Hess M et al. (2019) eNeuro "In-vivo quantitative image analysis of age-related morphological changes of C. elegans neurons reveals a correlation between neurite bending and novel neurite outgrowths."

Gomariz A, Ewald CY, Goksel O, Hess M

[eNeuro, 2019]

The aging of the human brain in the absence of diseases is accompanied by subtle changes of neuronal morphology, such as dendrite restructuring, neuronal sprouting, and synaptic deteriorations, rather than neurodegeneration or gross deterioration. Similarly, the nervous system of <i>C. elegans</i> does not show neurodegeneration or gross deterioration during normal aging, but displays subtle alterations in neuronal morphology. The occurrence of these age-dependent abnormalities is stochastic and dynamic, which poses a major challenge to fully capture them for quantitative comparison. Here, we developed a semi-automated pipeline for quantitative image analysis of these features during aging. We employed and evaluated this pipeline herein to reproduce findings from previous studies using visual inspection of neuronal morphology. Importantly, our approach can also quantify additional features, such as soma volume, the length of neurite outgrowths, and their location along the aged neuron. We found that, during aging, the soma of neurons decreases in volume, whereas the number and length of neurite outgrowths from the soma both increase. Long-lived animals showed less decrease in soma volume, fewer and shorter neurite outgrowths, and protection against abnormal sharp bends preferentially localized at the distal part of the dendrites during aging. We found a correlation of sharp bends with neurite outgrowth, suggesting the hypothesis that sharp bends might proceed neurite outgrowths. Thus, our semi-automated pipeline can help researchers to obtain and analyze quantitative datasets of this stochastic process for comparison across genotypes and to identify correlations to facilitate the generation of novel hypothesis.<b>Significance Statement</b> The etiology of age-dependent morphological changes in neurons remains elusive. The heterogeneity of these refinements requires an unbiased quantitative acquisition and analysis to pin-point the molecular underpinning of these structural changes. Here, we developed a work-flow and adopted algorithms to allow researchers to capture and analyse these age-dependent changes of <i>C. elegans</i> touch receptor neurons <i>in vivo</i> Increasing the traceability and quantification of these stochastic changes will aid researchers to gain mechanistic insights into the underlying biology of these age-dependent morphological changes in aging neurons.

Li S et al. (2002) J Biol Chem "Crystal structure of the cytoskeleton-associated protein glycine-rich (CAP-Gly) domain."

Zhao J, Wang BC, Luo M, Nagy LA, Luan CH, Liu ZJ, Sha B, Thomas W, Chen H, Li S, Lin G, Qiu SH, Johnson D, Tsao J, Carson M, Finley J, DeLucas LJ

[J Biol Chem, 2002]

Cytoskeleton-associated proteins (CAPs) are involved in the organization of microtubules and transportation of vesicles and organelles along the cytoskeletal network. A conserved motif, CAP-Gly, has been identified in a number of CAPs, including CLIP-170 and dynactins. The crystal structure of the CAP-Gly domain of Caenorhabditis elegans F53F4.3 protein, solved by single wavelength sulfur-anomalous phasing, revealed a novel protein fold containing three beta-sheets. The most conserved sequence, GKNDG, is located in two consecutive sharp turns on the surface, forming the entrance to a groove. Residues in the groove are highly conserved as measured from the information content of the aligned sequences. The C-terminal tail of another molecule in the crystal is bound in this groove.

Worrall L et al. (2006) Acta Crystallogr Sect F Struct Biol Cryst Commun "Crystallization and X-ray data analysis of the 10 kDa C-terminal lid subdomain from Caenorhabditis elegans Hsp70."

Worrall L, Walkinshaw MD

[Acta Crystallogr Sect F Struct Biol Cryst Commun, 2006]

Hsp70 is an important molecular chaperone involved in the regulation of protein folding. Crystals of the C-terminal 10 kDa helical lid domain (residues 542-640) from a Caenorhabditis elegans Hsp70 homologue have been produced that diffract X-rays to approximately 3.4 A. Crystals belong to space group I2(1)2(1)2(1), with unit-cell parameters a = b = 197, c = 200 A. The Matthews coefficient, self-rotation function and Patterson map indicate 24 monomers in the asymmetric unit, showing non-crystallographic 432 symmetry. Molecular-replacement studies using the corresponding domain from rat, the only eukaryotic homologue with a known structure, failed and a mercury derivative was obtained. Preliminary MAD phasing using SHELXD and SHARP for location and refinement of the heavy-atom substructure and SOLOMON for density modification produced interpretable maps with a clear protein-solvent boundary. Further density-modification, model-building and refinement are currently under way.

Cinquin A et al. (2015) Dev Cell "Semi-permeable Diffusion Barriers Enhance Patterning Robustness in the C. elegans Germline."

Nie Q, Taylor PH, Chiang M, Zhang L, Cinquin O, Zheng L, Snow JJ, Paz A, Cinquin A

[Dev Cell, 2015]

Positional information derived from local morphogen concentration plays an important role in patterning. A key question is how morphogen diffusion and gene expression regulation shape positional information into an appropriate profile with suitably low noise. We address this question using a model system--the C. elegans germline--whose regulatory network has been well characterized genetically but whose spatiotemporal dynamics are poorly understood. We show that diffusion within the germline syncytium is a critical control of stem cell differentiation and that semi-permeable diffusion barriers present at key locations make it possible--in combination with a feedback loop in the germline regulatory network--for mitotic zone size to be robust against spatial noise in Notch signaling. Spatial averaging within compartments defined by diffusion barriers is an advantageous patterning strategy, which attenuates noise while still allowing for sharp transitions between compartments. This strategy could apply to other organs.

Huang L et al. (2016) Comput Math Methods Med "A Run-Length Encoding Approach for Path Analysis of C. elegans Search Behavior."

Kim H, Huang L, Furst J, Raicu D

[Comput Math Methods Med, 2016]

The nematode Caenorhabditis elegans explores the environment using a combination of different movement patterns, which include straight movement, reversal, and turns. We propose to quantify C. elegans movement behavior using a computer vision approach based on run-length encoding of step-length data. In this approach, the path of C. elegans is encoded as a string of characters, where each character represents a path segment of a specific type of movement. With these encoded string data, we perform k-means cluster analysis to distinguish movement behaviors resulting from different genotypes and food availability. We found that shallow and sharp turns are the most critical factors in distinguishing the differences among the movement behaviors. To validate our approach, we examined the movement behavior of tph-1 mutants that lack an enzyme responsible for serotonin biosynthesis. A k-means cluster analysis with the path string-encoded data showed that tph-1 movement behavior on food is similar to that of wild-type animals off food. We suggest that this run-length encoding approach is applicable to trajectory data in animal or human mobility data.