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OALib Journal期刊

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Defects in Mitochondrial Fission Protein Dynamin-Related Protein 1 Are Linked to Apoptotic Resistance and Autophagy in a Lung Cancer Model
Kelly Jean Thomas, Marty R. Jacobson
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0045319
Abstract: Evasion of apoptosis is implicated in almost all aspects of cancer progression, as well as treatment resistance. In this study, resistance to apoptosis was identified in tumorigenic lung epithelial (A549) cells as a consequence of defects in mitochondrial and autophagic function. Mitochondrial function is determined in part by mitochondrial morphology, a process regulated by mitochondrial dynamics whereby the joining of two mitochondria, fusion, inhibits apoptosis while fission, the division of a mitochondrion, initiates apoptosis. Mitochondrial morphology of A549 cells displayed an elongated phenotype–mimicking cells deficient in mitochondrial fission protein, Dynamin-related protein 1 (Drp1). A549 cells had impaired Drp1 mitochondrial recruitment and decreased Drp1-dependent fission. Cytochrome c release and caspase-3 and PARP cleavage were impaired both basally and with apoptotic stimuli in A549 cells. Increased mitochondrial mass was observed in A549 cells, suggesting defects in mitophagy (mitochondrial selective autophagy). A549 cells had decreased LC3-II lipidation and lysosomal inhibition suggesting defects in autophagy occur upstream of lysosomal degradation. Immunostaining indicated mitochondrial localized LC3 punctae in A549 cells increased after mitochondrial uncoupling or with a combination of mitochondrial depolarization and ectopic Drp1 expression. Increased inhibition of apoptosis in A549 cells is correlated with impeded mitochondrial fission and mitophagy. We suggest mitochondrial fission defects contribute to apoptotic resistance in A549 cells.
The Potential of Aspen Clonal Forestry in Alberta: Breeding Regions and Estimates of Genetic Gain from Selection
Tim Gylander, Andreas Hamann, Jean S. Brouard, Barb R. Thomas
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0044303
Abstract: Background Aspen naturally grows in large, single-species, even-aged stands that regenerate clonally after fire disturbance. This offers an opportunity for an intensive clonal forestry system that closely emulates the natural life history of the species. In this paper, we assess the potential of genetic tree improvement and clonal deployment to enhance the productivity of aspen forests in Alberta. We further investigate geographic patterns of genetic variation in aspen and infer forest management strategies under uncertain future climates. Methodology/Principal Findings Genetic variation among 242 clones from Alberta was evaluated in 13 common garden trials after 5–8 growing seasons in the field. Broad-sense heritabilities for height and diameter at breast height (DBH) ranged from 0.36 to 0.64, allowing 5–15% genetic gains in height and 9–34% genetic gains in DBH. Geographic partitioning of genetic variance revealed predominant latitudinal genetic differentiation. We further observed that northward movement of clones almost always resulted in increased growth relative to local planting material, while southward movement had a strong opposite effect. Conclusion/Significance Aspen forests are an important natural resource in western Canada that is used for pulp and oriented strandboard production, accounting for ~40% of the total forest harvest. Moderate to high broad-sense heritabilities in growth traits suggest good potential for a genetic tree improvement program with aspen. Significant productivity gains appear possible through clonal selection from existing trials. We propose two breeding regions for Alberta, and suggest that well-tested southern clones may be used in the northern breeding region, accounting for a general warming trend observed over the last several decades in Alberta.
Observation of a single-beam gradient force acoustical trap for elastic particles: acoustical tweezers
Diego Baresch,Jean-Louis Thomas,Régis Marchiano
Physics , 2014,
Abstract: We demonstrate the trapping of elastic particles by the large gradient force of a single acoustical beam in three dimensions. Acoustical tweezers can push, pull and accurately control both the position and the forces exerted on a unique particle. Forces in excess of 1 micronewton were exerted on polystyrene beads in the sub-millimeter range. A beam intensity less than 50 Watts/cm$^2$ was required ensuring damage-free trapping conditions. The large spectrum of frequencies covered by coherent ultrasonic sources provide a wide variety of manipulation possibilities from macro- to microscopic length scales. Our observations could open the way to important applications, in particular in biology and biophysics at the cellular scale and for the design of acoustical machines in microfluidic environments.
A helium burst biolistic device adapted to penetrate fragile insect tissues
Jean-Luc Thomas,Jér？me Bardou,Sebastien L'hoste,Bernard Mauchamp
Journal of Insect Science , 2001,
Abstract: To compensate for the extremely low penetration efficiency of the original PDS/1000-He Bio Rad biolisticreg; device and the deleterious blast effect, design modifications have been made to the launching module. These modifications were evaluated on Bombyx mori embryos and fragile tissues, such as oocytes and imaginal wing disks. The original floppy macrocarrier was replaced by a rigid macrocarrier to avoid the effects of the helium blast. The efficiency of the gene gun bombardment was reinforced by the addition of a focusing nozzle. The reduced blast effect allowed us to carry out high-pressure shootings to small organs with improved penetration. This system allowed potentially all the internal embryonic tissues to be transfected with optimal survival rates. The new module was effective on tissues that are difficult to transfect, such as the epithelial wing disk that is covered by a peripodial membrane, and the ovarian follicle cells that lie under the ovariole cell membrane. The new macrocarrier allowed both an aqueous delivery of particles and an ethanolic dry delivery. No significant differences were noted between these two modes of delivery. The major improvement is the possibility of high pressure shooting correlated with appreciable penetration and a weak blast effect.
Challenges and complexities in application of LCA approaches in the case of ICT for a sustainable future
Reza Farrahi Moghaddam,Fereydoun Farrahi Moghaddam,Thomas Dandres,Yves Lemieux,Réjean Samson,Mohamed Cheriet
Computer Science , 2014,
Abstract: In this work, three of many ICT-specific challenges of LCA are discussed. First, the inconsistency versus uncertainty is reviewed with regard to the meta-technological nature of ICT. As an example, the semiconductor technologies are used to highlight the complexities especially with respect to energy and water consumption. The need for specific representations and metric to separately assess products and technologies is discussed. It is highlighted that applying product-oriented approaches would result in abandoning or disfavoring of new technologies that could otherwise help toward a better world. Second, several believed-untouchable hot spots are highlighted to emphasize on their importance and footprint. The list includes, but not limited to, i) User Computer-Interfaces (UCIs), especially screens and displays, ii) Network-Computer Interlaces (NCIs), such as electronic and optical ports, and iii) electricity power interfaces. In addition, considering cross-regional social and economic impacts, and also taking into account the marketing nature of the need for many ICT's product and services in both forms of hardware and software, the complexity of End of Life (EoL) stage of ICT products, technologies, and services is explored. Finally, the impact of smart management and intelligence, and in general software, in ICT solutions and products is highlighted. In particular, it is observed that, even using the same technology, the significance of software could be highly variable depending on the level of intelligence and awareness deployed. With examples from an interconnected network of data centers managed using Dynamic Voltage and Frequency Scaling (DVFS) technology and smart cooling systems, it is shown that the unadjusted assessments could be highly uncertain, and even inconsistent, in calculating the management component's significance on the ICT impacts.
Public Health Progress in Haiti
Carissa Etienne,David W. Lowrance,Jean Luc Poncelet,Jordan W. Tappero,Thomas R. Frieden
- , 2017, DOI: 10.4269/ajtmh.17-0347
Abstract:
The Interplay Between Spike-Time and Spike-Rate Modes in the Auditory Nerve Encodes Tone-In-Noise Threshold
Antoine Huet,Gilles Desmadryl,Jean-Luc Puel,Jér？me Bourien,Régis Nouvian,Thomas Justal
- , 2018, DOI: 10.1523/JNEUROSCI.3103-17.2018
Abstract: Auditory nerve fibers (ANFs) encode pure tones through two modes of coding, spike time and spike rate, depending on the tone frequency. In response to a low-frequency tone, ANF firing is phase locked to the sinusoidal waveform. Because time coding vanishes with an increase in the tone frequency, high-frequency tone coding relies on the spike rate of the ANFs. Adding a continuous broadband noise to a tone compresses the rate intensity function of ANFs and shifts its dynamic range toward higher intensities. Therefore, the ANFs with high-threshold/low-spontaneous rate (SR) are thought to contribute to behavioral tone detection in noise. However, this theory relies on the discharge rate of the ANFs. The direct comparison with the masking threshold through spike timing, irrespective of the spontaneous rate, has not so far been investigated. Taking advantage of a unique proxy to quantify the spike synchrony (i.e., the shuffle autocorrelogram), we show in female gerbils that high-SR ANFs are more adapted to encode low-frequency thresholds through temporal code, giving them a strong robustness in noise. By comparing behavioral thresholds measured using prepulse inhibition of the acoustical startle reflex with population thresholds calculated from ANFs pooled per octave band, we show that threshold-based spike timing provides a better estimate of behavioral thresholds in the low-frequency range, whereas the high-frequency behavioral thresholds rely on the spiking rate, particularly in noise. This emphasizes the complementarity of temporal and rate modes to code tone-in-noise thresholds over a large range of frequencies. SIGNIFICANCE STATEMENT There is a general agreement that high-threshold/low-spontaneous rate (SR) auditory nerve fibers (ANFs) are of prime importance for tone detection in noise. However, this theory is based on the discharge rate of the fibers. Comparing the behavioral thresholds and single ANF thresholds shows that this is only true in the high-frequency range of tone stimulations. In the low-frequency range of tones (up to 2.7 kHz in the gerbil), the most sensitive ANFs (high-SR fibers) carry neural information through a spike-timing mode, even for noise in which tones do not induce a noticeable increment in the spike rate. This emphasizes the interplay between spike-time and spike-rate modes in the auditory nerve to encode tone-in-noise threshold over a large range of tone frequencies
An Ethnomethodological Perspective on the Conflict between Magistrates and Journalists in Cameroon  [PDF]
Jean-Fran？ois Nguegan, Thomas Essono
Advances in Journalism and Communication (AJC) , 2015, DOI: 10.4236/ajc.2015.34013
Abstract: The report of the magistrate profession to that of a journalist in Cameroon can be studied from the perspective both of the sociology of professions and sociology of the conflict; the actors, who belong to different territories, are usually against the quality, legitimacy and competence required to deal with media information, and judicial control, individual freedom. This relationship is mainly studied in this research in terms of symbolic interactionism, to emphasize first of all on the importance that judges and journalists themselves give to their profession and secondly on the rationality of their game in the construction and the demarcation of their respective territories. This article is a contribution to the study of the discourse of these two groups of professionals who compete with each other.
Kinetics of HIV-1 CTL Epitopes Recognized by HLA I Alleles in HIV-Infected Individuals at Times near Primary Infection: The Provir/Latitude45 Study
Jennifer Papuchon, Patricia Pinson, Gwenda-Line Guidicelli, Pantxika Bellecave, Réjean Thomas, Roger LeBlanc, Sandrine Reigadas, Jean-Luc Taupin, Jean Guy Baril, Jean Pierre Routy, Mark Wainberg, Hervé Fleury, the Provir/Latitude 45 study group
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100452
Abstract: In patients responding successfully to ART, the next therapeutic step is viral cure. An interesting strategy is antiviral vaccination, particularly involving CD8 T cell epitopes. However, attempts at vaccination are dependent on the immunogenetic background of individuals. The Provir/Latitude 45 project aims to investigate which CTL epitopes in proviral HIV-1 will be recognized by the immune system when HLA alleles are taken into consideration. A prior study (Papuchon et al, PLoS ONE 2013) showed that chronically-infected patients under successful ART exhibited variations of proviral CTL epitopes compared to a reference viral strain (HXB2) and that a generic vaccine may not be efficient. Here, we investigated viral and/or proviral CTL epitopes at different time points in recently infected individuals of the Canadian primary HIV infection cohort and assessed the affinity of these epitopes for HLA alleles during the study period. An analysis of the results confirms that it is not possible to fully predict which epitopes will be recognized by the HLA alleles of the patients if the reference sequences and epitopes are taken as the basis of simulation. Epitopes may be seen to vary in circulating RNA and proviral DNA. Despite this confirmation, the overall variability of the epitopes was low in these patients who are temporally close to primary infection.
Alteration of Rat Fetal Cerebral Cortex Development after Prenatal Exposure to Polychlorinated Biphenyls
Elise Naveau, Anneline Pinson, Arlette Gérard, Laurent Nguyen, Corinne Charlier, Jean-Pierre Thomé, R. Thomas Zoeller, Jean-Pierre Bourguignon, Anne-Simone Parent
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0091903
Abstract: Polychlorinated biphenyls (PCBs) are environmental contaminants that persist in environment and human tissues. Perinatal exposure to these endocrine disruptors causes cognitive deficits and learning disabilities in children. These effects may involve their ability to interfere with thyroid hormone (TH) action. We tested the hypothesis that developmental exposure to PCBs can concomitantly alter TH levels and TH-regulated events during cerebral cortex development: progenitor proliferation, cell cycle exit and neuron migration. Pregnant rats exposed to the commercial PCB mixture Aroclor 1254 ended gestation with reduced total and free serum thyroxine levels. Exposure to Aroclor 1254 increased cell cycle exit of the neuronal progenitors and delayed radial neuronal migration in the fetal cortex. Progenitor cell proliferation, cell death and differentiation rate were not altered by prenatal exposure to PCBs. Given that PCBs remain ubiquitous, though diminishing, contaminants in human systems, it is important that we further understand their deleterious effects in the brain.
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