Search results for "physiologic"
showing 10 items of 2593 documents
The evolutionary history of symbiotic associations among bacteria and their animal hosts: a model
2009
AbstractA model to explain the evolutionary history of animal-bacteria obligatory mutualistic symbiosis is presented. Dispensability of genes and genetic isolation are key factors in the reduction process of these bacterial genomes. Major steps in such genome reductive evolution, leading towards primary endoslmblosis, and the possibility of complementation or replacement by a secondary symbiont are also indicated. Yet, we need to understand what happens at the beginning of the adaptative process towards an obligate mutualistic relationship. For this purpose, we propose to sequence the complete genome of SOPE, the primary endosymbiont of the rice weevil.
Between a rock and a soft place: the role of viruses in lithification of modern microbial mats.
2021
10 pages; International audience; Stromatolites are geobiological systems formed by complex microbial communities, and fossilized stromatolites provide a record of some of the oldest life on Earth. Microbial mats are precursors of extant stromatolites; however, the mechanisms of transition from mat to stromatolite are controversial and are still not well understood. To fully recognize the profound impact that these ecosystems have had on the evolution of the biosphere requires an understanding of modern lithification mechanisms and how they relate to the geological record. We propose here viral mechanisms in carbonate precipitation, leading to stromatolite formation, whereby viruses directl…
Genomics of intracellular symbionts in insects
2010
Endosymbiotic bacteria play a vital role in the evolution of many insect species. For instance, endosymbionts have evolved metabolically to complement their host's natural diet, thereby enabling them to explore new habitats. In this paper, we will review and give some examples of the nature of the metabolic coupling of different primary and secondary endosymbionts that have evolved in hosts with different nutritional diets (i.e., phloem, xylem, blood, omnivores, and grain). Particular emphasis is given to the evolutionary functional convergence of phylogenetically distant endosymbionts, which are evolving in hosts with similar diets.
Cortical inhibition and habituation to evoked potentials: relevance for pathophysiology of migraine
2009
Dysfunction of neuronal cortical excitability has been supposed to play an important role in etiopathogenesis of migraine. Neurophysiological techniques like evoked potentials (EP) and in the last years non-invasive brain stimulation techniques like transcranial magnetic stimulation (TMS) and transcranial direct current stimulation gave important contribution to understanding of such issue highlighting possible mechanisms of cortical dysfunctions in migraine. EP studies showed impaired habituation to repeated sensorial stimulation and this abnormality was confirmed across all sensorial modalities, making defective habituation a neurophysiological hallmark of the disease. TMS was employed to…
The Adoption of New Treatment Modalities by Health Professionals and the Relative Weight of Empirical Evidence in Favor of Virtual Reality Exposure V…
2020
Anxiety disorders are among the most prevalent mental disorders, and cognitive-behavioral therapy (CBT) with exposure exercises is considered as the gold-standard psychological intervention. New psychotherapeutic modalities have emerged in the last decade and, among them, mindfulness has been rapidly adopted by therapists. The adoption rate is slower for the use of virtual reality (VR) to conduct exposure. The goal of the present position paper is to contrast, for the treatment of anxiety disorders, the weight of empirical evidences supporting the use of exposure in VR with the use of mindfulness-based therapy (MBT). Based on the most recent meta-analyses, we found that CBT with exposure co…
Investigating the Effects of Differential Learning on Golfers’ Pitching Performance as a Function of Handicap
2022
Traditionally, golf instruction has been oriented toward imitation of role models, guided by errors that surround a channel of supposedly correct repetition. Recent motor learning approaches relying on the dynamics of living systems suggest the inclusion of additional noise during practice for supporting players’ movement exploration and improving adaptability that in consequence will lead to increased performance. While the effectiveness of this approach has now been demonstrated in many sports, research exploring the effects of differential learning (DL) in golf is scarce, especially when considering different shot distances and players with various handicap levels. Therefore, the p…
Nonclassical crystallization in vivo et in vitro (I): Process-structure-property relationships of nanogranular biominerals.
2016
A distinct nanogranular fine structure is shared by a wealth of biominerals from several species, classes and taxa. This nanoscopic organization affects the properties and behavior of the biogenic ceramic material and confers on them attributes that are essential to their function. We present a set of structure-relationship properties that are rooted in the nanogranular organization and we propose that they rest on a common pathway of formation, a colloid-driven and hence nonclassical mode of crystallization. With this common modus operandi, we reveal the most fundamental and wide spread process-structure-property relationship in biominerals. With the recent increase in our understanding of…
A Critical Period for Prefrontal Network Configurations Underlying Psychiatric Disorders and Addiction
2020
The medial prefrontal cortex (mPFC) has been classically defined as the brain region responsible for higher cognitive functions, including the decision-making process. Ample information has been gathered during the last 40 years in an attempt to understand how it works. We now know extensively about the connectivity of this region and its relationship with neuromodulatory ascending projection areas, such as the dorsal raphe nucleus (DRN) or the ventral tegmental area (VTA). Both areas are well-known regulators of the reward-based decision-making process and hence likely to be involved in processes like evidence integration, impulsivity or addiction biology, but also in helping us to predict…
Being in the Past and Perform the Future in a Virtual World: VR Applications to Assess and Enhance Episodic and Prospective Memory in Normal and Path…
2020
The process of aging commonly features a gradual deterioration in cognitive performance and, in particular, the decline of memory. Despite the increased longevity of the world's population, the prevalence of neurodegenerative conditions, such as dementia, continues to be a major burden on public health, and consequently, the latest research has been focused on memory and aging. Currently, the failure of episodic and Prospective memory (PM) is one of the main complaints in the elderly, considered among the early symptoms of dementia. It is therefore increasingly important to define more clearly the boundaries between normal and pathological aging. Recently, researchers have begun to build an…
Redox signaling (cross-talk) from and to mitochondria involves mitochondrial pores and reactive oxygen species
2010
This review highlights the important role of redox signaling between mitochondria and NADPH oxidases. Besides the definition and general importance of redox signaling, the cross-talk between mitochondrial and Nox-derived reactive oxygen species (ROS) is discussed on the basis of 4 different examples. In the first model, angiotensin-II is discussed as a trigger for NADPH oxidase activation with subsequent ROS-dependent opening of mitochondrial ATP-sensitive potassium channels leading to depolarization of mitochondrial membrane potential followed by mitochondrial ROS formation and respiratory dysfunction. This concept was supported by observations that ethidium bromide-induced mitochondrial d…