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[
Journal of Morphology,
1930]
Intravitam stains were used to determine the functions of several organs in two species of nemas (Rhabditis strongyloides and Rhabditis elongata). The organs were also studied in section. From the results obtained it is concluded that the amphids are not excretory in function, but more probably sensory, for definite connections were observed to extend to the nerve ring. No migratory cells, such as those described by Stefanski, were seen. The phasmids stained with all intravitam stains used, but were never observed to secrete. It seems doubtful that they serve as excretory organs. The excretory system was seen to consist of a typical X system. Actual excretion was observed. Deirids were seen for the first time in both species. Oesophageal glands were also described. A study was made of the structure of the intestinal cells, rectal glands, and anal muscles. Attention was called to the fact that there are two kinds of ejaculatory glands, one of which probably serves as a 'cement gland', while the function of the other is still in doubt.
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Adv Exp Med Biol,
2008]
Model organisms are vital to our understanding of human muscle biology and disease. The potential of the nematode Caenorhabditis elegans, the fruitfly, Drosophila melanogaster and the zebrafish, Danio rerio, as model genetic organisms for the study of human muscle disease is discussed by examining their muscle biology, muscle genetics and development. The powerful genetic tools available with each organism are outlined. It is concluded that these organisms have already demonstrated potential in facilitating the study of muscle disease and in screening for therapeutic agents.
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Recent Developments in Cell Research,
2003]
In muscle cells, the actin cytoskeleton is differentiated into myofibrils that are specialized contractile apparatuses. To assemble and maintain myofibrils, a specific regulatory mechanism of actin filament dynamics is required. The actin depolymerizing factor (ADF)/cofilin proteins are ubiquitous regulators of actin turnover among eukaryotes. However, muscle-specific ADF/cofilin isoforms are present in several species and play important roles in actin organization in muscle cells. This review describes the function of ADF/cofilin as an important regulator of myofibril assembly and muscle diseases.
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J Biomed Biotechnol,
2010]
C. elegans is an excellent model for studying nonmuscle cell focal adhesions and the analogous muscle cell attachment structures. In the major striated muscle of this nematode, all of the M-lines and the Z-disk analogs (dense bodies) are attached to the muscle cell membrane and underlying extracellular matrix. Accumulating at these sites are many proteins associated with integrin. We have found that nematode M-lines contain a set of protein complexes that link integrin-associated proteins to myosin thick filaments. We have also obtained evidence for intriguing additional functions for these muscle cell attachment proteins.
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Sci Robot,
2021]
Analysis of <i>Caenorhabditis elegans</i> natural movement and optogenetic control of its muscle cells enable controlled locomotion.
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Anat Rec (Hoboken),
2014]
The nematode Caenorhabditis elegans has been used as a valuable system to study structure and function of striated muscle. The body wall muscle of C. elegans is obliquely striated muscle with highly organized sarcomeric assembly of actin, myosin, and other accessory proteins. Genetic and molecular biological studies in C. elegans have identified a number of genes encoding structural and regulatory components for the muscle contractile apparatuses, and many of them have counterparts in mammalian cardiac and skeletal muscles or striated muscles in other invertebrates. Applicability of genetics, cell biology, and biochemistry has made C. elegans an excellent system to study mechanisms of muscle contractility and assembly and maintenance of myofibrils. This review focuses on the regulatory mechanisms of structure and function of actin filaments in the C. elegans body wall muscle. Sarcomeric actin filaments in C. elegans muscle are associated with the troponin-tropomyosin system that regulates the actin-myosin interaction. Proteins that bind to the side and ends of actin filaments support ordered assembly of thin filaments. Furthermore, regulators of actin dynamics play important roles in initial assembly, growth, and maintenance of sarcomeres. The knowledge acquired in C. elegans can serve as bases to understand the basic mechanisms of muscle structure and function.
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Worm,
2012]
Protein degradation is a fundamental cellular process, the genomic control of which is incompletely understood. The advent of transgene-coded reporter proteins has enabled the development of C. elegans into a model for studying this problem. The regulation of muscle protein degradation is surprisingly complex, integrating multiple signals from hypodermis, intestine, neurons and muscle itself. Within the muscle, degradation is executed by separately regulated autophagy-lysosomal, ubiquitin-proteasome and calpain-mediated systems. The signal-transduction mechanisms, in some instances, involve modules previously identified for their roles in developmental processes, repurposed in terminally differentiated muscle to regulate the activities of pre-formed proteins. Here we review the genes, and mechanisms, which appear to coordinately control protein degradation within C. elegans muscle. We also consider these mechanisms in the context of development, physiology, pathophysiology and disease models.
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[
1980]
Muscle contraction is one of the fundamental processes of animal life. Although biochemical, biophysical, and electron microscopic studies have yielded much valuable information about the structure and function of muscle and its component proteins, there are still many unanswered questions. For example, little is known about the molecular basis for gene expression during the development of muscle, the regulation of synthesis and function of muscle proteins, and the in vivo assembly of the myofilament lattice. Progress in answering these types of questions has been hindered in the past by the lack of a system in which one could use biochemical, biophysical, and cytological techniques in analyzing an animal also suitable for genetic and developmental studies of muscle. However, recent work has demonstrated rather convincingly that the nematode, Caenorhabditis elegans, will be very useful for attacking these problems.
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Annual Review of Genetics,
1989]
Striated muscle functions universally to generate biological force. It contains two major filament systems, the myosin-containing thick filaments and the actin-containing thin filaments. During contraction, hydrolysis of ATP by a myosin-linked ATPase causes thin filaments to slide past thick filaments, thus shortening the sarcomere and producing tension on the contractile unit. During the past decade or two, the small nematode Caenorhabditis elegans has emerged as an important experimental organism for the study of muscle structure, assembly, and function. Like muscle biologists in general, C. elegans investigators are concerned with the questions: What are the components of striated muscle? How are these components assembled within the cell? How do these components function during the contractile cycle?...
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[
1986]
Our efforts to understand the role of each of the muscle genes in C. elegans myogenesis and muscle contraction have followed three different but interrelated approaches. Antibodies have been developed and used to define additional components of C. elegans body wall musculature. Studies of gene interactions have revealed epistatic relationships that help to define the function of some gene products. Transposition of the repetitive element Tc1 into the muscle gene
unc-22 has allowed us to clone this gene and begin the dissection of its function in the nematode.