Download or read book Neuronal Regulation of Chemosensory Signaling in Caenorhabditis Elegans written by Meredith Jean Ezak and published by . This book was released on 2011 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: All animals rely on their ability to sense and respond to their constantly changing environments to survive. Caenorhabditis elegans depend heavily upon their ability to taste and smell chemical information in their soil habitat to find favorable conditions and avoid noxious environments. While similar signal transduction pathways are implicated in both C. elegans and vertebrate chemosensation, there are still large gaps in our understanding of the mechanisms used to regulate signaling in these systems. I have sought to define cellular pathways that modulate signaling activity, and ultimately responsiveness, of chemosensory neurons in C. elegans. I describe herein the identification of cell- and modality-specific pathways that regulate neuronal activity in response to aberrant signaling, as well as a novel mechanism by which neuronal cells may regulate expression of sensory genes to directly impact cellular activity.

Download or read book Regulatory Mechanisms of Chemosensory Signaling in Caenorhabditis Elegans written by Michelle Christine Krzyzanowski and published by . This book was released on 2015 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: All animals rely on their ability to sense and respond to their environment to survive. While similar signal transduction pathways are implicated in both C. elegans and vertebrate chemosensation, there are still large gaps in our understanding of the mechanisms used to regulate signaling in these systems. In my thesis, I have identified a new role for the C. elegans cGMP-dependent protein kinase (PKG) EGL-4 in the negative regulation of nociceptive chemosensory signaling. Nociceptive sensory systems detect harmful stimuli and allow for the initiation of protective behavioral responses. The polymodal ASH sensory neurons are the primary nociceptors in C. elegans. The data suggest that EGL-4 negatively regulates signaling and behavior by activating known inhibitors of G protein-coupled signal transduction, RGS proteins. Using C. elegans behavioral response to aversive stimuli as the readout for neuronal activity, I provide the first evidence for PKG regulation of RGS function in sensory neurons in any system. Additionally, the suitability of a behavioral response is context-dependent, and must reflect both an animal's life history and its present internal state. Based on the integration of these variables, an animal's needs can be prioritized to optimize survival strategies. I show that cGMP movement through a gap junction neural network allows dynamic repurposing of several C. elegans head sensory neurons to regulate ASH sensitivity through EGL-4 function in response to an animal's feeding status. Such decentralized regulation of ASH signaling allows for rapid correlation between an animal's internal state and its behavioral output, and lends an unexpected modulatory flexibility to this hard-wired nociceptive neural circuit.

Download or read book The Neurobiology of Olfaction written by Anna Menini and published by CRC Press. This book was released on 2009-11-24 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive Overview of Advances in OlfactionThe common belief is that human smell perception is much reduced compared with other mammals, so that whatever abilities are uncovered and investigated in animal research would have little significance for humans. However, new evidence from a variety of sources indicates this traditional view is likely

Download or read book E coli in Motion written by Howard C. Berg and published by Springer Science & Business Media. This book was released on 2008-01-11 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Escherichia coli, commonly referred to as E. coli, has been the organism of choice for molecular genetics for decades. Its machinery and mobile behavior is one of the most fascinating topics for cell scientists. Scientists and engineers, not trained in microbiology, and who would like to learn more about living machines, can see it as a unique example. This cross-disciplinary monograph covers more than thirty years of research and is accessible to graduate students and scientists alike.

Download or read book Neurotransmission Defines Functional Chemosensory Neural Circuits to Regulate Behavior written by Sarah Goldberg Leinwand and published by . This book was released on 2015 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neural circuits detect and process environmental changes to drive appropriate food-seeking or toxin-avoiding behaviors. However, we lack a complete understanding of the cellular and molecular mechanisms that represent chemosensory cues and generate appropriate behaviors. Furthermore, these vital sensory abilities deteriorate with age in humans and most animals, but it is unknown how aging impairs the underlying neural circuits to cause sensory behavioral declines. With powerful genetic tools, a complete connectome and robust chemosensory behaviors, the nematode Caenorhabditis elegans is ideally suited for a circuit-level analysis of these behaviors in young and aged animals. The aim of this dissertation is to identify neural signaling and circuit principles for flexibly encoding chemosensory stimuli and generating behavioral plasticity in C. elegans, which may be broadly conserved. In Chapters 2 and 3, I define a novel, sensory context-dependent and neuropeptide-regulated switch in the composition of a C. elegans salt sensory circuit. The ASE primary salt sensory neurons cleave and release insulin-like peptides in response to large but not small changes in external salt stimuli. Insulin signaling functionally switches the AWC olfactory sensory neuron into an interneuron in the high salt circuit, potentiating behavioral responses. Thus, sensory context and neuropeptide signaling act together to shape the flow of information in active neural circuits, suggesting a general mechanism for generating dynamic behavioral outputs. In Chapter 4, I identify an aging-associated decline in C. elegans olfactory behavior and map a novel underlying circuit motif. Two primary olfactory sensory neuron pairs, AWC and AWA, directly detect benzaldehyde and release insulin peptides and acetylcholine to activate two secondary neuron pairs, ASE and AWB, and drive behavioral plasticity. Interestingly, odor-evoked activity in the secondary, but not primary, neurons degrades with age. Experimental manipulations to increase primary neuron transmitter release rescue these aging-associated neuronal deficits. Furthermore, aged animals' olfactory abilities are correlated with lifespan, suggesting that olfaction may be indicative of overall health and physiology. These results show how chemosensory stimuli are encoded by a population code composed of primary and secondary neurons and suggest reduced neurotransmission as a novel mechanism driving aging-associated sensory neural activity and behavioral declines. In sum, this dissertation establishes the crucial role of peptidergic and classical neurotransmission in defining the active neural circuit configurations that regulate chemosensory behaviors.

Download or read book Chemosensory Receptors in Caenorhabditis Elegans written by Emily Troemel and published by . This book was released on 1999 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Studies of Chemosensory Signal Transduction in Caenorhabditis Elegans written by Kayvan Roayaie and published by . This book was released on 1996 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book C Elegans II written by Donald L. Riddle and published by Firefly Books. This book was released on 1997 with total page 1252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Defines the current status of research in the genetics, anatomy, and development of the nematode C. elegans, providing a detailed molecular explanation of how development is regulated and how the nervous system specifies varied aspects of behavior. Contains sections on the genome, development, neural networks and behavior, and life history and evolution. Appendices offer genetic nomenclature, a list of laboratory strain and allele designations, skeleton genetic maps, a list of characterized genes, a table of neurotransmitter assignments for specific neurons, and information on codon usage. Includes bandw photos. For researchers in worm studies, as well as the wider community of researchers in cell and molecular biology. Annotation copyrighted by Book News, Inc., Portland, OR

Download or read book The Neurobiology of C elegans written by and published by Elsevier. This book was released on 2006-02-02 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Neurobiology of C. elegans assembles together a series of chapters describing the progress researchers have made toward solving some of the major problems in neurobiology with the use of this powerful model organism. The first chapter is an introduction to the anatomy of the C. elegans nervous system. This chapter provides a useful introduction to this system and will help the reader who is less familiar with this system understand the chapters that follow. The next two chapters on learning, conditioning and memory and neuronal specification and differentiation, summarize the current state of the C. elegans field in these two major areas of neurobiology. The remaining chapters describe studies in C. elegans that have provided particularly exciting insights into neurobiology.

Download or read book C Elegans Atlas written by David H. Hall and published by CSHL Press. This book was released on 2008 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: Derived from the acclaimed online “WormAtlas,†C. elegansAtlas is a large-format, full-color atlas of the hermaphroditic form of the model organism C. elegans, known affectionately as “the worm†by workers in the field. Prepared by the editors of the WormAtlas Consortium, David H. Hall and Zeynep F. Altun, this book combines explanatory text with copious, labeled, color illustrations and electron micrographs of the major body systems of C. elegans. Also included are electron microscopy cross sections of the worm. This laboratory reference is essential for the working worm biologist, at the bench and at the microscope, and provides a superb companion to the C. elegansII monograph. It is also a valuable tool for investigators in the fields of developmental biology, neurobiology, reproductive biology, gene expression, and molecular biology.

Download or read book Neuronal Inputs and Outputs of Aging and Longevity written by Joy Alcedo and published by Frontiers. This book was released on 2013-08-23 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: An animal’s survival strongly depends on its ability to maintain homeostasis in response to the changing quality of its external and internal environments. This is achieved through intercellular communication not only within a single tissue but also among different tissues and organ systems. Thus, alterations in tissue-to-tissue or organ-to-organ communications, which are under genetic regulation, can affect organismal homeostasis, and consequently impact the aging process. One of the organ systems that play a major role in maintaining homeostasis is the nervous system. Considering that the nervous system includes the sensory system, which perceives the complexity of an animal’s environment, it should be no surprise that there would be a sensory influence on homeostasis and aging. To promote homeostasis, any given sensory information is transmitted through short-range signals via neural circuits and/or through long-range endocrine signals to target tissues, which may in turn be neuronal or non-neuronal in nature. At the same time, since homeostasis involves a number of feedback mechanisms, non-neuronal tissues can also modulate sensory and other neuronal functions. Several genes that regulate signaling pathways known to affect homeostasis and aging have been shown to act in neurons, in tissues that are likely downstream targets of the nervous system, or through feedback regulation of neuronal activities. These genes can have different temporal requirements: some might function early, e.g., by affecting neural development, while others may only be required later in adulthood. Some well-known examples of genes involved in the neuronal regulation of homeostasis and longevity encode components of the evolutionarily conserved nutrient-sensing insulin/insulin-like signaling pathway, the stress-sensing internal repair system, and the mitochondrial electron transport chain. Indeed, the genetic perturbation of these pathways has been found to lead to numerous diseases, many of which are age-related and involve the nervous system, such as neurodegeneration and the metabolic syndrome. Despite much progress, however, many aspects of the neuronal inputs and outputs that affect aging and longevity are poorly understood to date. For example, the precise neuronal and non-neuronal circuitries and the details of the molecular mechanisms through which genes/signaling pathways maintain homeostasis and affect aging in response to the environment remain to be elucidated. Similarly, it is presently unclear whether genes that regulate the early development of the nervous system and its consequent circuitry influence homeostasis and longevity during adulthood. At the same time, although many genes affecting aging are conserved, both the nervous system and the aging process are highly variable within populations and among taxa. Accordingly, the role of natural genetic variation in shaping the neurobiology of aging is also presently unknown. The aim of this Research Topic is therefore to highlight the genetic, developmental, and physiological aspects of the signaling networks that mediate the neuronal inputs and outputs that are required to maintain organismal homeostasis. The elucidation of the effects of these neuronal activities on homeostasis may thus provide much-needed insight into mechanisms that affect aging and longevity.

Download or read book Mechanisms by which Feeding State and Sex are Integrated to Regulate Chemosensory Plasticity in C Elegans written by Leigh R. Wexler and published by . This book was released on 2019 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: The feeding-state of an animal can have deep effects on its chemosensation and behavioral decisions. Although many internal signals of nutritional state and hunger are known, the mechanisms by which these modulate neural circuits and behavior are less well understood. C. elegans display an interesting intersection of feeding state and sex in the regulation of chemosensory behavior. Self-fertile hermaphrodites exhibit strong food attraction while males prioritize mate-searching over feeding. This sexual dimorphism is regulated in part through differences the chemoreceptor ODR-10, which detects the food-associated odorant diacetyl in the AWA neuron. Hermaphrodites expresses high levels of odr-10 while in adult males, expression of odr-10 is low, promoting exploratory behavior. However, starved males transiently upregulate odr-10 to generate stronger food attraction until their nutritional needs are met. This multi-layered regulation of odr-10 provides an opportunity to study how neural circuits integrate genetic sex and feeding-state to regulate chemosensory behaviors through chemoreceptor expression. We show that in response to food availability, odr-10 is modulated in males through insulin-like signaling and DAF-7/TGF? signaling. Interestingly, we find that in males odr-10 is regulated primarily by sensory perception of food, not metabolic starvation. Similarly, the TGF? ligand daf-7 is regulated in the ASJ neuron by food perception, linking environmental signals to odr-10. Additionally, these mechanisms are modulated by sex. We show hermaphrodites also regulate odr-10 in response to feeding state, however they do so through divergent mechanisms from males, independent of insulin and TFG? signaling and in response to metabolic starvation. Through this work we identify a male-specific mechanisms which modulates chemosensation based on environmental conditions furthering our understanding of how chemoreceptor expression and behavioral choice is regulated through multiple internal and external states.

Download or read book Microbial Endocrinology written by Mark Lyte and published by Springer Science & Business Media. This book was released on 2010-04-06 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial endocrinology represents a newly emerging interdisciplinary field that is formed by the intersection of the fields of neurobiology and microbiology. This book will introduce a new perspective to the current understanding not only of the factors that mediate the ability of microbes to cause disease, but also to the mechanisms that maintain normal homeostasis. The discovery that microbes can directly respond to neuroendocrine hormones, as evidenced by increased growth and production of virulence-associated factors, provides for a new framework with which to investigate how microorganisms interface not only with vertebrates, but also with invertebrates and even plants. The reader will learn that the neuroendocrine hormones that one most commonly associates with mammals are actually found throughout the plant, insect and microbial communities to an extent that will undoubtedly surprise many, and most importantly, how interactions between microbes and neuroendocrine hormones can influence the pathophysiology of infectious disease.

Download or read book Genomic Regulatory Systems written by Eric H. Davidson and published by Elsevier. This book was released on 2001-01-24 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interaction between biology and evolution has been the subject of great interest in recent years. Because evolution is such a highly debated topic, a biologically oriented discussion will appeal not only to scientists and biologists but also to the interested lay person. This topic will always be a subject of controversy and therefore any breaking information regarding it is of great interest.The author is a recognized expert in the field of developmental biology and has been instrumental in elucidating the relationship between biology and evolution. The study of evolution is of interest to many different kinds of people and Genomic Regulatory Systems: In Development and Evolution is written at a level that is very easy to read and understand even for the nonscientist. * Contents Include* Regulatory Hardwiring: A Brief Overview of the Genomic Control Apparatus and Its Causal Role in Development and Evolution * Inside the Cis-Regulatory Module: Control Logic and How the Regulatory Environment Is Transduced into Spatial Patterns of Gene Expression* Regulation of Direct Cell-Type Specification in Early Development* The Secret of the Bilaterians: Abstract Regulatory Design in Building Adult Body Parts* Changes That Make New Forms: Gene Regulatory Systems and the Evolution of Body Plans

Download or read book Regulation of Neuronal Polarity in C Elegans by TOE 2 and Wnt Signaling written by Mark Andrew Gurling and published by . This book was released on 2012 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cellular polarization is an important aspect of neural development. During the development of the C. elegans nervous system, many divisions are asymmetric and give rise to neurons and cells that die. While we understand how cells die in C. elegans, we know much less about how cells are instructed to adopt the apoptotic fate. To address this issue, I studied the Q.p neuroblast, which divides to produce a larger anterior cell and a smaller posterior cell that dies. The surviving Q.p daughter divides again to form the neurons A/PVM and SDQ. A forward-genetic screen for mutants with extra A/PVMs in order to identify genes that regulate the apoptotic fate was conducted previously in the lab. A mutant, gm389, was isolated. In gm389, I identified a mutation in the gene toe-2, which encodes a target of the worm ERK ortholog, MPK-1. I found that TOE-2 not only regulates the apoptotic fate of the posterior Q.p daughter, but it also plays a role in the asymmetric division of Q, the mother of Q.p. I found that TOE-2 functions autonomously in the Q lineage where it regulates several asymmetric cell divisions (ACDs). I also show that, during Q lineage cell divisions, TOE-2 localizes to centrosomes, to the posterior cortex and at the site where the cleavage furrow will form. Cellular polarization is also required for the function of mature neurons. The function of a neuron is facilitated by its distinct morphology. Electrical signals are propagated along neuronal processes that extend from the cell body to form connections with muscle cells, sensory structures or other neurons. In vitro studies of developing neurons have shown that a neuronal process forms at random from one of many smaller processes protruding from the developing cell. Many intracellular molecules necessary for this process have been identified. However, many neurons display invariant polarity in vivo, suggesting specific regulation of the polarization process by external signals. Wnts and Frizzled receptors have been shown to direct polarization of mechanosensory neurons along the C. elegans anterior/posterior (AP) axis. It was shown that ectopic expression of MIG-1 in PLM reverses PLM polarity. I show that ectopic expression of the cysteine-rich domain of MIG-1 in PLM is not sufficient to cause a polarity reversal. I also show that the activity of MIG-1 in PLM is dependent upon the Wnt EGL-20.

Download or read book Sensory Integration of Odor and Food Signaling in a Primary Sensory Neuron in C Elegans written by Jin Il Lee and published by . This book was released on 2008 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Egl 4 Mediates Sensory Regulation of Multiple Neuronal Signaling Pathways in C Elegans written by Susan A. Daniels and published by . This book was released on 2000 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: