-
[
Front Physiol,
2020]
Water is critical for the survival of most cells and organisms. Remarkably, a small number of multicellular animals are able to survive nearly complete drying. The phenomenon of anhydrobiosis, or life without water, has been of interest to researchers for over 300 years. In this review we discuss advances in our understanding of protectants and mechanisms of desiccation tolerance that have emerged from research in three anhydrobiotic invertebrates: brine shrimp (<i>Artemia</i>), roundworms (nematodes), and tardigrades (water bears). Discovery of molecular protectants that allow each of these three animals to survive drying diversifies our understanding of desiccation tolerance, and convergent themes suggest mechanisms that may offer a general model for engineering desiccation tolerance in other contexts.
-
[
Am J Physiol Regul Integr Comp Physiol,
2013]
Intracellular salt and water homeostasis is essential for all cellular life. Extracellular salt and water homeostasis is also important for multicellular organisms. Many fundamental mechanisms of compensation for osmotic perturbations are well defined and conserved. Alternatively, molecular mechanisms of detecting salt and water imbalances and regulating compensatory responses are generally poorly defined for animals. Throughout the last century, researchers studying vertebrates and vertebrate cells made critical contributions to our understanding of osmoregulation, especially mechanisms of salt and water transport and organic osmolyte accumulation. Researchers have more recently started using invertebrate model organisms with defined genomes and well-established methods of genetic manipulation to begin defining the genes and integrated regulatory networks that respond to osmotic stress. The nematode Caenorhabditis elegans is well suited to these studies. Here, I introduce osmoregulatory mechanisms in this model, discuss experimental advantages and limitations, and review important findings. Key discoveries include defining genetic mechanisms of osmolarity sensing in neurons, identifying protein damage as a sensor and principle determinant of hypertonic stress resistance, and identification of a putative sensor for hypertonic stress associated with the extracellular matrix. Many of these processes and pathways are conserved and, therefore, provide new insights into salt and water homeostasis in other animals, including mammals.
-
[
Dev Cell,
2004]
Currently, perhaps the most significant biological problem is to understand the mechanisms of learning and memory, and many of the answers will come from molecular explanations of synaptic plasticity. Two new papers have established a surprising connection: the Anaphase Promoting Complex/Cyclosome (APC/C) has a second function in controlling local protein stability at synapses, and hence in the control of behavior (Juo and Kaplan, 2004; van Roessel et al., 2004).
-
[
Exp Gerontol,
2006]
Caenorhabditis elegans has been used to model aspects of a number of age-associated neurodegenerative diseases, including Alzheimer''s, Parkinson''s and Huntington''s diseases. These models have typically involved the transgenic expression of disease-associated human proteins. Here I describe my laboratory''s specific experience engineering C. elegans models of Alzheimer''s disease, and give a general consideration of the advantages and disadvantages of these C. elegans models. The type of insights that might be gained from using these (relatively) simple models are highlighted. In particular, I consider the potential these models have for uncovering common and unique fundamental toxic mechanisms underlying human neurodegenerative diseases.
-
[
Hermann, Editeurs des Sciences et des Arts. Paris, France.,
2002]
L'espce Caenorhabditis elegans fut dcrite en 1900 Alger par E. Maupas, qui s'intressait son mode de reproduction hermaphrodite. Plus tard, vers le milieu du vingtime sicle, V. Nigon et ses collaboratuers Lyon tudirent les reorganizations cellulaires accompagnant la fecundation et les premiers clivages. J. Brun isola les preiers mutants morpholgiques.
-
[
Curr Biol,
2001]
When meiotic cells complete S phase, homologous chromosomes pair, synapse and undergo recombination. A checkpoint protein is somehow required for meiotic chromosome pairing in C. elegans, thus providing a direct link between S phase and the rest of the meiotic program.
-
[
Mol Biochem Parasitol,
2005]
Nematodes are among the most successful organisms in withstanding stress conditions associated with water loss, and viable individuals have been recovered from dry desert soils. Little is known about the biochemical and molecular events underpinning nematodes' physiological responses to dehydration. Post-genomics research in Caenorhabditis elegans may offer an opportunity to understand the stress response better. This review focuses on recent progress in understanding the molecular mechanisms of water-loss associated stress response in the model nematode C. elegans and in parasitic nematodes and discusses the scope for applying the knowledge and tools derived from a model organism for the study of wild, environmentally-adapted, parasitic nematodes, in the light of the emergence of genomics research of non-model organisms.
-
[
Toxins (Basel),
2016]
Staphylococcus aureus is an opportunistic pathogen and the leading cause of a wide range of severe clinical infections. The range of diseases reflects the diversity of virulence factors produced by this pathogen. To establish an infection in the host, S. aureus expresses an inclusive set of virulence factors such as toxins, enzymes, adhesins, and other surface proteins that allow the pathogen to survive under extreme conditions and are essential for the bacteria's ability to spread through tissues. Expression and secretion of this array of toxins and enzymes are tightly controlled by a number of regulatory systems. S. aureus is also notorious for its ability to resist the arsenal of currently available antibiotics and dissemination of various multidrug-resistant S. aureus clones limits therapeutic options for a S. aureus infection. Recently, the development of anti-virulence therapeutics that neutralize S. aureus toxins or block the pathways that regulate toxin production has shown potential in thwarting the bacteria's acquisition of antibiotic resistance. In this review, we provide insights into the regulation of S. aureus toxin production and potential anti-virulence strategies that target S. aureus toxins.
-
[
Nat Rev Mol Cell Biol,
2014]
Many organs contain networks of epithelial tubes that transport gases or fluids. A lumen can be generated by tissue that enwraps a pre-existing extracellular space or it can arise de novo either between cells or within a single cell in a position where there was no space previously. Apparently distinct mechanisms of de novo lumen formation observed in vitro - in three-dimensional cultures of endothelial and Madin-Darby canine kidney (MDCK) cells - and in vivo - in zebrafish vasculature, Caenorhabditis elegans excretory cells and the Drosophila melanogaster trachea - in fact share many common features. In all systems, lumen formation involves the structured expansion of the apical plasma membrane through general mechanisms of vesicle transport and of microtubule and actin cytoskeleton regulation.
-
[
Biochem Soc Trans,
2020]
DNA replication is a complex process that needs to be executed accurately before cell division in order to maintain genome integrity. DNA replication is divided into three main stages: initiation, elongation and termination. One of the key events during initiation is the assembly of the replicative helicase at origins of replication, and this mechanism has been very well described over the last decades. In the last six years however, researchers have also focused on deciphering the molecular mechanisms underlying the disassembly of the replicative helicase during termination. Similar to replisome assembly, the mechanism of replisome disassembly is strictly regulated and well conserved throughout evolution, although its complexity increases in higher eukaryotes. While budding yeast rely on just one pathway for replisome disassembly in S phase, higher eukaryotes evolved an additional mitotic pathway over and above the default S phase specific pathway. Moreover, replisome disassembly has been recently found to be a key event prior to the repair of certain DNA lesions, such as under-replicated DNA in mitosis and inter-strand cross-links (ICLs) in S phase. Although replisome disassembly in human cells has not been characterised yet, they possess all of the factors involved in these pathways in model organisms, and de-regulation of many of them are known to contribute to tumorigenesis and other pathological conditions.