-
[
J Neurobiol,
1993]
Mutations causing a touch-insensitive phenotype in the nematode Caenorhabditis elegans have been the basis of studies on the specification of neuronal cell fate, inherited neurodegeneration, and the molecular nature of mechanosensory transduction. (C) 1993 John Wiley & sons, Inc.
-
[
IUBMB Life,
2015]
Foodborne infections caused by non-typhoidal Salmonellae, such as Salmonella enterica serovar Typhimurium (ST), pose a major challenge in the developed and developing world. With constant rise of drug-resistant strains, understanding the epidemiology, microbiology, pathogenesis and host-pathogen interactions biology is a mandatory requirement to enable health systems to be ready to combat these illnesses. Patient data from hospitals, at least from some parts of the world, have aided in epidemiological understanding of ST-mediated disease. Most of the other aspects connected to Salmonella-host crosstalk have come from model systems that offer convenience, genetic tractability and low maintenance costs that make them extremely valuable tools. Complex model systems such as the bovine model have helped in understanding key virulence factors needed for infection. Simple systems such as fruit flies and Caenorhabditis elegans have aided in identification of novel virulence factors, host pathways and mechanistic details of interactions. Some of the path-breaking concepts of the field have come from mice model of ST colitis, which allows genetic manipulations as well as high degree of similarity to human counterpart. Together, they are invaluable for correlating in vitro findings of ST-induced disease progression in vivo. The current review is a compilation of various advances of ST-host interactions at cellular and molecular levels that has come from investigations involving model organisms.
-
[
Human Genome News,
1999]
For the first time, scientists have the nearly complete genetic instructions for an animal that, like humans, has a nervous system, digests food, and reproduces sexually. The 97-million-base genome of the tiny roundworm Caenorhabditis elegans was deciphered by an international team led by Robert Waterston and John Sulston. The work was reported in a special issue of the journal Science (December 11, 1998) that featured six articles describing the history and significance of the accomplishment and some early sequence-analysis results.
-
[
Science,
1994]
In 1967, Sydney Brenner isolated the first behavioral mutants of the nematode Caenorhabditis elegans, and in 1970, John White began the systematic reconstruction of its nervous system. This dual approach of genetics coupled with detailed morphological analysis, now enhanced by the tools of molecular biology and electrophysiology, still dominates the study of the function and development of the C. elegans nervous system. Although Brenner's vision of a comprehensive understanding of this simple animal has taken time to mature, findings of the past few years indicate that the tree is bearing fruit.
-
[
Parasitol Today,
1990]
Many aspects of the biology of kinetoplastids are unique, so it is surprising that they share with nematodes an unusual post-transcriptional process called trans-splicing. During this process, a small conserved RNA sequence is added to the 5' non-translated ends of transcribed RNAs of protein-encoding genes. Trypanosomes and nematodes are the only organisms to date in which these sequences have been described, and the biological significance of trans-splicing remains a mystery but may be of wider occurrence in invertebrates. In this review, John Donelson and Wenlin Zeng compare the process in nematodes and trypanosomes and speculate on its raison d'etre.
-
[
Genome Res,
1995]
Caenorhabditis elegans, a free-living nematode worm, has proved a particularly useful model organism for studying the anatomy, behavior, genetics, and development of a metazoan. It also has one of the smallest genomes of the higher eukaryotes (100 Mb distributed over six chromosomes), making it an ideal candidate for detailed molecular analysis. The C. elegans genome project began over 10 years ago and is a collaberative effort between two laboratories (St. Louis, MO, USA and Cambridge, UK), with the ultimate aim of mapping and sequencing the whole of the 100-Mb genome. The consortium has now completed the sequence of approximately one-fifth of the genome and plans to have sequenced more than half the genome before the end
-
[
Studies of History & Philosophy of Science,
1998]
In 1963, just a year after the researchers of the Medical Research Council (MRC) Unit of Molecular Biology in Cambridge, joined by some other research groups, has moved from various scattered and makeshift buildings in the courtyard of the Physics Department to a lavishly funded four-storey laboratory, B. Lush, the Principal Medical Officer of the MRC, came to inquire about their plans for future expansion. He indicated that the MRC wished to build the laboratory up to what the principal researchers considered its 'final size' until their retirement, which meant planning ahead for at least 15 years. This surprising move was doubtless prompted by the recent award of the Nobel Prize to three members of the laboratory, Max Perutz, John Kendrew and Francis Crick, for their work on the molecular structure of proteins and nucleic acids. The triple award had propelled the new Laboratory of Molecular Biology into the limelight, and the MRC was interested in securing optimal research conditions for this prestigious group of researchers.
-
[
Science,
2004]
I'm one of the 2000 or so worm people who study the tiny nematode Caenorhabditis elegans. When we are asked by an outsider why we play with worms, our much-practiced answer goes something like this: In the
mid-1960s, Sydney Brenner chose C. elegans as a model organism for elucidating animal development and behavior because of the roundworm's cellular simplicity and advantages for genetic studies. The analysis of mutants helps us learn what the nonmutant versions of genes do. We know the location and lineage of every cell in an adult C. elegans as well as the wiring of all the worm's 302 neurons, down to the last synapse. C. elegans was the first multicellular organism to have its DNA completely sequenced (1), and many of its genes resemble those of humans and do similar jobs. The importance of such research was highlighted when Brenner, John Sulston, and Bob Horvitz were awarded the 2002 Nobel Prize in physiology or medicine for their worm work.
-
[
J Pathol,
2009]
Virtually every tissue of the adult organism maintains a population of putatively slowly-cycling stem cells that maintain homeostasis of the tissue and respond to injury when challenged. These cells are regulated and supported by the surrounding microenvironment, referred to as the stem cell ''niche''. The niche includes all cellular and non-cellular components that interact in order to control the adult stem cell, and these interactions can often be broken down into one of two major mechanistic categories-physical contact and diffusible factors. The niche has been studied directly and indirectly in a number of adult stem cell systems. Herein, we will first focus on the most well-understood niches supporting the germline stem cells in the lower organisms Caenorhabditis elegans and Drosophila melanogaster before concentrating on the more complex, less well-understood mammalian niches supporting the neural, epidermal, haematopoietic and intestinal stem cells. Copyright (c) 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
-
[
Front Genet,
2018]
In the last decade, case studies in plants and animals provided increasing insight into the molecular mechanisms of developmental plasticity. When complemented with evolutionary and ecological analyses, these studies suggest that plasticity represents a mechanism facilitating adaptive change, increasing diversity and fostering the evolution of novelty. Here, we summarize genetic, molecular and evolutionary studies on developmental plasticity of feeding structures in nematodes, focusing on the model organism <i>Pristionchus pacificus</i> and its relatives. Like its famous cousin <i>Caenorhabditis elegans</i>, <i>P. pacificus</i> reproduces as a self-fertilizing hermaphrodite and can be cultured in the laboratory on <i>E. coli</i> indefinitely with a four-day generation time. However, in contrast to <i>C. elegans</i>, <i>Pristionchus</i> worms show more complex feeding structures in adaptation to their life history. <i>Pristionchus</i> nematodes live in the soil and are reliably found in association with scarab beetles, but only reproduce after the insects' death. Insect carcasses usually exist only for a short time period and their turnover is partially unpredictable. Strikingly, <i>Pristionchus</i> worms can have two alternative mouth-forms; animals are either stenostomatous (St) with a single tooth resulting in strict bacterial feeding, or alternatively, they are eurystomatous (Eu) with two teeth allowing facultative predation. Laboratory-based studies revealed a regulatory network that controls the irreversible decision of individual worms to adopt the St or Eu form. These studies revealed that a developmental switch controls the mouth-form decision, confirming long-standing theory about the role of switch genes in developmental plasticity. Here, we describe the current understanding of <i>P. pacificus</i> mouth-form regulation. In contrast to plasticity, robustness describes the property of organisms to produce unchanged phenotypes despite environmental perturbations. While largely opposite in principle, the relationship between developmental plasticity and robustness has only rarely been tested in particular study systems. Based on a study of the Hsp90 chaperones in nematodes, we suggest that robustness and plasticity are indeed complementary concepts. Genetic switch networks regulating plasticity require robustness to produce reproducible responses to the multitude of environmental inputs and the phenotypic output requires robustness because the range of possible phenotypic outcomes is constrained. Thus, plasticity and robustness are actually not mutually exclusive, but rather complementary concepts.