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[
Nematologica,
1971]
Caenorhabditis briggsae was used as a model to study aging of a metazoan under gnotobiotic conditions. At higher temperatures nematodes were shorter-lived and had a shorter generation time. Nematodes moved more slowly as they aged. Physiologic aging was marked by a decreased ability to withstand osmotic stress, a possible increase in the body's internal solute concentration, and increased sensitivity to formaldehyde. These results suggest that the ability to osmoregulate and the permeability of the body wall are altered during senescence. The interchordal hypodermis, as well as the chordal hypodermis, contained fairly abundant structures having biosynthetic activity. During aging mitochondria of the hypodermis degenerated, some areas of the thin hypodermal band thickened and lysosome-like bodies formed in the interchordal hypodermis. Changes in osmoregulatory and excretory mechanisms are probably associated with deterioration of hypodermis organelles.
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Curr Opin Genet Dev,
1993]
Understanding of the C. elegans homeobox gene cluster has been significantly expanded since the genes
egl-5 and
lin-39 have been shown to correspond to homeobox genes in the cluster. Genes of the homeobox cluster not only function as regionally restricted homeotic genes along the anterior-posterior body axis, but also control cell migrations within the affected body regions.
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[
WormBook,
2006]
Sarcomeres within body wall muscle in C. elegans include attachments to the sarcolemma that are remarkably similar in structure to vertebrate adhesion complexes. Crucial early steps in muscle sarcomere assembly, a highly orchestrated affair involving many proteins, involve the assembly of these sarcomere attachments. The steps involved in initiating the correct placement of these attachments and other sarcomere substructures are poorly understood. Using mutants in C. elegans we are attempting to dissect the various steps in this process. We review what has been discovered to date and present a model of sarcomere assembly that initiates at the plasma membrane and involves proteins within muscle, the hypodermis and within the extracellular matrix.
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[
Science,
1994]
Worms, butterflies, and chimpanzees all have the same body axes-head and tail, front and back, and left and right sides. How are these axes established during development? Is there a single molecular map used by most metazoan embryos or have similar coordinates been achieved during evolution by diverse routes? A comparison of the mechanisms that establish body axes in distantly related organisms can begin to answer this fundamental question.
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[
J Muscle Res Cell Motil,
2007]
During evolution, both the architecture and the cellular physiology of muscles have been remarkably maintained. Striated muscles of invertebrates, although less complex, strongly resemble vertebrate skeletal muscles. In particular, the basic contractile unit called the sarcomere is almost identical between vertebrates and invertebrates. In vertebrate muscles, sarcomeric actin filaments are anchored to attachment points called Z-disks, which are linked to the extra-cellular matrix (ECM) by a muscle specific focal adhesion site called the costamere. In this review, we focus on the dense body of the animal model Caenorhabditis elegans. The C. elegans dense body is a structure that performs two in one roles at the same time, that of the Z-disk and of the costamere. The dense body is anchored in the muscle membrane and provides rigidity to the muscle by mechanically linking actin filaments to the ECM. In the last few years, it has become increasingly evident that, in addition to its structural role, the dense body also performs a signaling function in muscle cells. In this paper, we review recent advances in the understanding of the C. elegans dense body composition and function.
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[
Environmental Toxicology and Chemistry,
1999]
The nematode Caenorhabditis elegans (Maupas) was exposed in a sediment bioassay to 26 different unpolluted freshwater sediments varying in particle size distribution (2.5-18% clay, 25.7-68.2% silt, 18.7-70.9% sand) and organic content (2.5-77.1%). We examined the variation of the test endpoints body length, eggs per worm, and percentage of gravid worms. Caenorhabditis elegans tolerated all investigated sediments, with at least 80% (total mean 96.6%) of the worms reaching the stage of reproductive adults. Variation in body length was small (total mean 1,235 +/- 97.8 mu m), but significant differences among the various sediments were found. We found a weak correlation of body length with particle size distribution, indicating that the nematodes grew better in coarser sediments. The number of eggs per worm showed relatively high variation among treatments (total mean 12.4 +/- 4.8) and also within treatments (mean +/- 5-95%). C. elegans is a suitable test organism for freshwater sediment bioassays, using body length and percentage of gravid worms as test endpoints.
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[
Trends Neurosci,
2015]
Homeosis is classically defined as the transformation of one body part into something that resembles another body part. We propose here to broaden the concept of homeosis to the many neuronal cell identity transformations that have been uncovered over the past few years upon removal of specific regulatory factors in organisms from Caenorhabditis elegans to Drosophila, zebrafish, and mice. The concept of homeosis provides a framework for the evolution of cell type diversity in the brain.
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[
Cilia,
2017]
The free-living nematode, Caenorhabditis elegans, is a widely used genetic model organism for investigations into centriole and cilia biology. Only sensory neurons are ciliated in C. elegans; morphologically diverse cilia in these neurons are nucleated by basal bodies located at the dendritic endings. C. elegans centrioles comprise a central tube with a symmetric array of nine singlet microtubules. These singlet microtubules remodel in a subset of sensory neurons to form the doublet microtubules of the basal bodies. Following initiation of ciliogenesis, the central tube, but not the outer centriole wall, of the basal body degenerates. Recent ultrastructural characterization of basal body architecture and remodeling have laid the foundation for future studies into mechanisms underlying different aspects of basal body genesis, remodeling, and intracellular positioning.
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[
Curr Opin Genet Dev,
2007]
Migrating neuronal cells are directed to their final positions by an array of guidance cues. It has been shown that guidance molecules such as UNC-6/Netrin and SLT-1/Slit play a major role in controlling cell and axon migrations along the dorsal-ventral body axis. Much less is known, however, about the mechanisms that mediate migration along the anterior-posterior (AP) body axis. Recent research in Caenorhabditis elegans has uncovered an important role of the Wnt family of signalling molecules in controlling AP-directed neuronal cell migration and polarity. A common theme that emerges from these studies is that multiple Wnt proteins function in parallel as instructive cues or permissive signals to control neuronal patterning along this major body axis.
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[
Annu Rev Physiol,
2015]
Over the past decade, studies conducted in Caenorhabditis elegans have helped to uncover the ancient and complex origins of body fat regulation. This review highlights the powerful combination of genetics, pharmacology, and biochemistry used to study energy balance and the regulation of cellular fat metabolism in C. elegans. The complete wiring diagram of the C. elegans nervous system has been exploited to understand how the sensory nervous system regulates body fat and how food perception is coupled with the production of energy via fat metabolism. As a model organism, C. elegans also offers a unique opportunity to discover neuroendocrine factors that mediate direct communication between the nervous system and the metabolic tissues. The coming years are expected to reveal a wealth of information on the neuroendocrine control of body fat in C. elegans.