-
[
J Cell Sci,
2004]
Junctional adhesion molecules (JAMs) are members of an immunoglobulin subfamily expressed by leukocytes and platelets as well as by epithelial and endothelial cells, in which they localize to cell-cell contacts and are specifically enriched at tight junctions. The recent identification of extracellular ligands and intracellular binding proteins for JAMs suggests two functions for JAMs. JAMs associate through their extracellular domains with the leukocyte beta2 integrins LFA-1 and Mac-1 as well as with the beta1 integrin alpha4beta1. All three integrins are involved in the regulation of leukocyte-endothelial cell interactions. Through their cytoplasmic domains, JAMs directly associate with various tight junction-associated proteins including ZO-1, AF-6, MUPP1 and the cell polarity protein PAR-3. PAR-3 is part of a ternary protein complex that contains PAR-3, atypical protein kinase C and PAR-6. This complex is highly conserved through evolution and is involved in the regulation of cell polarity in organisms from Caenorhabditis elegans and Drosophila to vertebrates. These findings point to dual functions for JAMs: they appear to regulate both leukocyte/platelet/endothelial cell interactions in the immune system and tight junction formation in epithelial and endothelial cells during the acquisition of cell polarity.
-
[
Journal of Neuroscience,
2004]
-
[
Pflugers Arch,
2015]
Mechanosensory neurons, whose activity is controlled by mechanical force, underlie the senses of touch, hearing, and proprioception, yet despite their importance, the molecular basis of mechanotransduction is poorly understood. Genetic studies in Caenorhabditis elegans have provided a useful approach for identifying potential components of mechanotransduction complexes that might be conserved in more complex organisms. This review describes the mechanosensory systems of C. elegans, including the sensory neurons and circuitry involved in body touch, nose touch, and proprioception. In addition, the roles of genes encoding known and potential mechanosensory receptors, including members of the broadly conserved transient receptor potential (TRP) and degerin/epithelial Na(+) channel (DEG/ENaC) channel families, are discussed.
-
[
Molecules,
2023]
Pheromones are chemical signals secreted by one individual that can affect the behaviors of other individuals within the same species. Ascaroside is an evolutionarily conserved family of nematode pheromones that play an integral role in the development, lifespan, propagation, and stress response of nematodes. Their general structure comprises the dideoxysugar ascarylose and fatty-acid-like side chains. Ascarosides can vary structurally and functionally according to the lengths of their side chains and how they are derivatized with different moieties. In this review, we mainly describe the chemical structures of ascarosides and their different effects on the development, mating, and aggregation of nematodes, as well as how they are synthesized and regulated. In addition, we discuss their influences on other species in various aspects. This review provides a reference for the functions and structures of ascarosides and enables their better application.
-
[
Molecules & Cells,
2004]
The conserved Ca2+/calmodulin-dependent phosphatase calcineurin has been shown to be involved in numerous and diverse functions both at the cellular and organism level. Recent genetic and pharmacological studies in animals including C. elegans, Drosophila, Aplysia, rat and mice have also implicated calcineurin in behavior, particularly in the regulation of plasticity and modulation of behaviors. These studies have not only brought a clearer understanding of the molecular contributions to behavior, but should also give insight into roles that calcineurin may be playing in the cognitive and behavioral defects
-
[
ACS Chem Biol,
2006]
Whereas the C. elegans genome was sequenced many years ago, the role of small molecule signals in its biology is still poorly understood. A recent publication reports the identification of two steroidal signaling molecules that regulate C. elegans reproductive development and dauer diapause via the nuclear receptor DAF-12. The two compounds, named dafachronic acids, represent the first endogenous ligands identified for any of the 284 nuclear receptors in C. elegans .
-
[
Annu Rev Neurosci,
1997]
Mechanosensation, the transduction of mechanical forces into a cellular electrochemical signal, enables living organisms to detect touch; vibrations, such as sound; accelerations, including gravity; body movements; and changes in cellular volume and shape. Ion channels directly activated by mechanical tension are thought to mediate mechanosensation in many systems. Only one channel has been cloned that is unequivocably mechanically gated: the MscL channel in bacteria. Genetic screens for touch-insensitive nematodes or flies promise to identify the proteins that constitute a mechanosensory apparatus in eukaryotes. In Caenorhabditis elegans, the mec genes thus identified encode molecules for a candidate structure, which includes a "degenerin" channel tethered to specialized extracellular and intracellular structural proteins. In hair cells of the inner ear, evidence suggests that an extracellular tip link pulls on a channel, which attached intracellularly to actin via a tension-regulating myosin 1beta. The channel and the tip link have not been cloned. Because degenerins and MscL homologs have not been found outside of nematodes and prokaryotes, respectively, and because intracellular and extracellular accessory structures apparently differ among organs and species, it may be that mechanosensory channel complexes evolved multiple times.
-
[
J Neurobiol,
2004]
Genetic analysis of nociceptive behaviors in the nematode Caenorhabditis elegans and the fruit fly Drosophila melanogaster has led to the discovery of conserved sensory transduction channels and signaling molecules. These are embedded in neurons and circuits that generate responses to noxious signals. This article reviews the neurons and molecular mechanisms that underlie invertebrate nociception. We begin with the neurobiology of invertebrate nociception, and then focus on molecules with conserved functions in vertebrate nociception and sensory biology. Copyright 2004 Wiley Periodicals, Inc. J Neurobiol 61: 161-174, 2004
-
[
EXS,
1993]
Receptors for acetylcholine are present in nematodes. Studies using physiological and biochemical methods have revealed the existence of nicotinic acetylcholine receptors with a novel pharmacology. Caenorhabditis elegans provides a particularly suitable organism with which to investigate such receptors using molecular genetic approaches. Mutants resistant to the cholinergic agonist (and anthelmintic drug) levamisole have permitted the isolation of a number of genes, including structural subunits of the nicotinic acetylcholine receptor. The only known viable mutants of nicotinic receptors are those of Caenorhabditis elegans. This organism offers the prospect of studying the developmental and regulatory effects of the loss of a single component of the receptor. Using Caenorhabditis elegans it is possible to select interesting phenotypic mutations by in vivo mutagenesis before determining the causative lesion. Resistance genes other than those encoding structural subunits are of particular interest, as they will encode additional polypeptides closely associated with nicotinic receptor function. Such proteins are often difficult or impossible to identify using conventional biochemical approaches, whereas genetic selection should permit their identification.
-
[
Molecules,
2016]
The study of model organisms is very important in view of their potential for application to human therapeutic uses. One such model organism is the nematode worm, Caenorhabditis elegans. As a nematode, C. elegans have ~65% similarity with human disease genes and, therefore, studies on C. elegans can be translated to human, as well as, C. elegans can be used in the study of different types of parasitic worms that infect other living organisms. In the past decade, many efforts have been undertaken to establish interdisciplinary research collaborations between biologists, physicists and engineers in order to develop microfluidic devices to study the biology of C. elegans. Microfluidic devices with the power to manipulate and detect bio-samples, regents or biomolecules in micro-scale environments can well fulfill the requirement to handle worms under proper laboratory conditions, thereby significantly increasing research productivity and knowledge. The recent development of different kinds of microfluidic devices with ultra-high throughput platforms has enabled researchers to carry out worm population studies. Microfluidic devices primarily comprises of chambers, channels and valves, wherein worms can be cultured, immobilized, imaged, etc. Microfluidic devices have been adapted to study various worm behaviors, including that deepen our understanding of neuromuscular connectivity and functions. This review will provide a clear account of the vital involvement of microfluidic devices in worm biology.