Body size change in various nematodes depending on bacterial food, sex and growth temperature
Shuhei So, Yohei Garan, Kohji Miyahara and Yasumi Ohshima
Pages 93 - 97
http://dx.doi.org/10.4161/worm.20175
Abstract
We previously reported significant body size change in the nematode Caenorhabditis elegans, depending on the food strain of E. coli. Here, we examined this body size change in 11 other nematode species as well, and found that it is common to most of these nematodes. Furthermore, this food-dependent body size change is influenced by sex and growth temperature.
Open Access
Phenotypic plasticity in nematodes: Evolutionary and ecological significance
Mark Viney and Anaid Diaz
Pages 98 - 106
http://dx.doi.org/10.4161/worm.21086
Abstract
Model systems, including C. elegans, have been successfully studied to understand the genetic control of development. A genotype’s phenotype determines its evolutionary fitness in natural environments, which are typically harsh, heterogeneous and dynamic. Phenotypic plasticity, the process by which one genome can produce different phenotypes in response to the environment, allows genotypes to better match their phenotype to their environment. Phenotypic plasticity is rife among nematodes, seen both as differences among life-cycles stages, perhaps best exemplified by parasitic nematodes, as well as developmental choices, such as shown by the C. elegans dauer/non-dauer developmental choice. Understanding the genetic basis of phenotypically plastic traits will probably explain the function of many genes whose function still remains unclear. Understanding the adaptive benefits of phenotypically plastic traits requires that we understand how plasticity differs among genotypes, and the effects of this in diverse, different environments.
Open Access
Finding a niche for seam cells?
Charles Brabin and Alison Woollard
Pages 107 - 111
http://dx.doi.org/10.4161/worm.19417
Abstract
The C. elegans neuroectodermal seam cells provide a tractable and well-established model for studying the stem cell mode of division, due to the reiterative asymmetric divisions occurring during larval development. They are, however, not generally considered to be ‘true’ stem cells, owing to their eventual terminal differentiation and the lack of a defined stem cell niche—a microenvironment that promotes the proliferation and prevents the differentiation of the stem cells that reside within. Here, we discuss the concept of the niche in relation to the seam, with reference to our recent findings suggesting that the stem-like properties of the seam cells are maintained at least in part through protection from differentiation signals emanating from the surrounding hypodermal syncytium. Determining the applicability of the niche concept will require definition of these signals and will have important implications for the status of seam cells in the context of stem cell biology.
Open Access
Nuclear positioning in the gonadal distal tip cells of C. elegans
Hon-Song Kim and Kiyoji Nishiwaki
Pages 112 - 115
http://dx.doi.org/10.4161/worm.19500
Abstract
Morphogenesis of the hermaphrodite gonad of Caenorhabditis elegans is directed by the U-shaped migration of the gonadal leader cells, which are called distal tip cells (DTCs). The nuclei of migrating DTCs are always positioned at the leading edge of the cells, even as these cells turn dorsally to contact the hypodermis and intestine. When the DTCs turn dorsally, VAB-10B1/spectraplakin acts in nuclear translocation by regulating the polarized growth of microtubules. The function of spectraplakin in nuclear positioning may be evolutionarily conserved. Here we discuss the possible reason for leading-edge positioning of the DTC nucleus.
Open Access
A connectivity model for the locomotor network of Caenorhabditis elegans
Gal Haspel and Michael J. O’Donovan
Pages 125 - 128
http://dx.doi.org/10.4161/worm.19392
Abstract
Recently, we described a new method for representing and analyzing the connectivity of a motoneuronal network. We used it to deduce a connectivity model for the neuromuscular network that generates locomotion in the nematode Caenorhabditis elegans. The network regulates muscle contraction and for this reason we used the location or function of body wall muscles to map every element (neuron or muscle cell) in a new framework, namely the peri-motor space. The previously published connectivity data for C. elegans locomotion network are incomplete; in particular, the connectivity of motoneurons in the posterior half of the animal is missing or partial. When we analyzed the connectivity data for motoneurons in the anterior half, we detected repeating patterns which we named iterativity. We analyzed the iterativity of each class of motoneuron and statistically validated that it is higher than expected by chance. We could then extrapolate the iteration into the posterior half. Here we will explain the new terms and elaborate on the process of analysis and the features of the new connectivity model.
Open Access
The wounded worm: Using C. elegans to understand the molecular basis of skin wound healing
Suhong Xu, Tiffany I. Hsiao and Andrew D. Chisholm
Pages 134 - 138
http://dx.doi.org/10.4161/worm.19501
Abstract
The ability to heal wounds is an ancient and conserved function of epidermal epithelial layers. The importance of skin wound healing to human life and biology has long been evident, however many of the molecular mechanisms underlying wound repair remain little understood. In the past several years, analysis of the C. elegans innate immune response to fungal infection of the epidermis has led to investigations of the ability of the C. elegans skin to respond to damage. In a recent paper we used live imaging to investigate the cell biological basis of wound repair in the adult C. elegans epidermis. We found that needle or laser injury of the skin triggers a large and sustained increase in epidermal calcium. Epidermal calcium signals appear to specifically promote actin-dependent processes of wound closure. The innate immune and wound closure responses act in parallel to promote survival after injury. Our findings indicate that wounding triggers multiple signals in the C. elegans skin. C. elegans offers a tractable model to dissect how epidermal epithelia activate coordinated responses to repair damage.
Open Access
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