Utilización de herramientas de simulación en la robótica industrial

Análisis de herramienta de simulación utilizada en el entorno industrial y estudio de las ventajas de la programación "offline" en un entorno productivo. Programación de una célula de trabajo industrial y ampliación posterior de la misma utilizando la herramienta de simulación industrial

Réseau régulatoire de HDAC3 pour comprendre les mécanismes de différenciation et de pathogenèse de Toxoplasma gondii

Apicomplexan genome architecture is typified by a binary chromatin structure, with a major fraction of the bulk genome packaged as transcriptionally permissive euchromatin while few loci are embedded in silenced heterochromatin. There is evidence that histone modifications occurring at the lateral surface of the nucleosome play a substantial role in shaping chromatin structure, yet our understanding of the exact mechanism of action is poor. Here, we address how versatile modifications at Lys31 within the globular domain of histone H4 contribute to genome organization and expression in Apicomplexa. H4K31 acetylation was found at the promoter of active genes. The residue lies where the DNA wraps around the histone and its acetylation may enhance nucleosome disassembly, thereby favoring a more relaxed, open chromatin state. This residue tends also to be monomethylated and depending of the parasite examined different patterns were found. H4K31me1 was enriched in the core body of Toxoplasma active genes, yet its occupancy was inversely correlated with transcripts levels likely because the mark by reducing histone turnover impedes RNA polymerase progression across transcribed units. In contrast to the methylation of H3, it is the first time that a methylated residue of H4 has been clearly associated with transcriptional regulation. In Plasmodium, H4K31me1 was exclusively enriched at transcriptionally inactive genomic regions and peculiarly at pericentromeric heterochromatin, likely to replace the missing H3K9me3 that commonly decorated pericentric nucleosomes in other species.Apicomplexan parasites are leading causes of human and livestock diseases such as toxoplasmosis and malaria caused by Toxoplasma gondii and Plasmodium falciparum respectively. These organisms are varied in their morphologies and astoundingly complex on their life cycles that include infections of more than one host organism, differentiation through several morphologically distinct forms, and both sexual and asexual replication. What we and others have initially proposed was that the control of gene expression and cellular differentiation are particularly interesting in these organisms, as the apparent lack of large families of recognizable transcription factors typically found in other eukaryotic organisms suggests that they may be unusually reliant on epigenetic mechanisms. The initial hypothesis had to be re-assessed in light of the discovery in Apicomplexa of an expanded family of plant-like transcription factors (TFs) harbouring APETALA2 (AP2)-like domains. Yet, a growing body of evidence tends to favor epigenetic as one of the main contributor to parasite developmental programs and adjustments to fluctuant environment. One way to examine dynamic changes in post-translations modifications (PTMs) patterns is to alter the histone code writing. We therefore took advantage of HDAC inhibitors and showed that specific inhibition of TgHDAC3 by the cyclopeptide FR235222 disrupts the genome wide steady-state level of histone H4 acetylation inducing derepression of stage-specific genes. Yet, many questions about TgHDAC3 modus operandi remain unanswered. During my thesis, I uncovered the TgHDAC3-regulated proteome-wide acetylome typified by the presence of non-histone proteins including AP2 TFs and novel PTMs, e.g. the acetylation at Lys31 within the globular domain of histone H4. H4K31ac promotes a relaxed chromatin state at the promoter of active genes through nucleosome disassembly in both parasites. We identified TgGCN5B and TgHDAC3 as two antagonist enzymes regulating H4K31 acetylation in T. gondii. In contrast, H4K31monomethylation is enriched throughout the gene body of T. gondii active genes and contributes to transcription, whereas it is enriched at transcriptionally inactive pericentromeric heterochromatin regions in P. falciparum, a region that is lacking H3K9me3 and heterochromatin protein 1 in this parasite. We also showed that treating T. gondii cystogenic strains with a low dose of FR235222 induces the levels of proteins known to be expressed exclusively in cat (sporozoite and merozoite) or in murine chronic stage (bradyzoite). Lastly, we determined the specific interactome of TgHDAC3 and found as partners a MORC protein (CR230), several AP2 TFs, and ELM2 domain-containing scaffolding proteins. Collectively, these data established TgHDAC3 family as a central regulator of gene expression and stage conversion in T. gondii and, likely, other Apicomplexa

Characterization of histone modifications inside nucleosome H4K31ac and H4K31me1 in Apicomplexan parasites

Apicomplexan parasites are leading causes of human and livestock diseases such as toxoplasmosis and malaria caused by Toxoplasma gondii and Plasmodium falciparum respectively. These organisms are varied in their morphologies and astoundingly complex on their life cycles that include infections of more than one host organism, differentiation through several morphologically distinct forms, and both sexual and asexual replication. What we and others have initially proposed was that the control of gene expression and cellular differentiation are particularly interesting in these organisms, as the apparent lack of large families of recognizable transcription factors typically found in other eukaryotic organisms suggests that they may be unusually reliant on epigenetic mechanisms. The initial hypothesis had to be re-assessed in light of the discovery in Apicomplexa of an expanded family of plant-like transcription factors (TFs) harbouring APETALA2 (AP2)-like domains. Yet, a growing body of evidence tends to favor epigenetic as one of the main contributor to parasite developmental programs and adjustments to fluctuant environment. One way to examine dynamic changes in post-translations modifications (PTMs) patterns is to alter the histone code writing. We therefore took advantage of HDAC inhibitors and showed that specific inhibition of TgHDAC3 by the cyclopeptide FR235222 disrupts the genome wide steady-state level of histone H4 acetylation inducing derepression of stage-specific genes. Yet, many questions about TgHDAC3 modus operandi remain unanswered. During my thesis, I uncovered the TgHDAC3-regulated proteome-wide acetylome typified by the presence of non-histone proteins including AP2 TFs and novel PTMs, e.g. the acetylation at Lys31 within the globular domain of histone H4. H4K31ac promotes a relaxed chromatin state at the promoter of active genes through nucleosome disassembly in both parasites. We identified TgGCN5B and TgHDAC3 as two antagonist enzymes regulating H4K31 acetylation in T. gondii. In contrast, H4K31monomethylation is enriched throughout the gene body of T. gondii active genes and contributes to transcription, whereas it is enriched at transcriptionally inactive pericentromeric heterochromatin regions in P. falciparum, a region that is lacking H3K9me3 and heterochromatin protein 1 in this parasite. We also showed that treating T. gondii cystogenic strains with a low dose of FR235222 induces the levels of proteins known to be expressed exclusively in cat (sporozoite and merozoite) or in murine chronic stage (bradyzoite). Lastly, we determined the specific interactome of TgHDAC3 and found as partners a MORC protein (CR230), several AP2 TFs, and ELM2 domain-containing scaffolding proteins. Collectively, these data established TgHDAC3 family as a central regulator of gene expression and stage conversion in T. gondii and, likely, other Apicomplexa.Apicomplexan genome architecture is typified by a binary chromatin structure, with a major fraction of the bulk genome packaged as transcriptionally permissive euchromatin while few loci are embedded in silenced heterochromatin. There is evidence that histone modifications occurring at the lateral surface of the nucleosome play a substantial role in shaping chromatin structure, yet our understanding of the exact mechanism of action is poor. Here, we address how versatile modifications at Lys31 within the globular domain of histone H4 contribute to genome organization and expression in Apicomplexa. H4K31 acetylation was found at the promoter of active genes. The residue lies where the DNA wraps around the histone and its acetylation may enhance nucleosome disassembly, thereby favoring a more relaxed, open chromatin state. This residue tends also to be monomethylated and depending of the parasite examined different patterns were found. H4K31me1 was enriched in the core body of Toxoplasma active genes, yet its occupancy was inversely correlated with transcripts levels likely because the mark by reducing histone turnover impedes RNA polymerase progression across transcribed units. In contrast to the methylation of H3, it is the first time that a methylated residue of H4 has been clearly associated with transcriptional regulation. In Plasmodium, H4K31me1 was exclusively enriched at transcriptionally inactive genomic regions and peculiarly at pericentromeric heterochromatin, likely to replace the missing H3K9me3 that commonly decorated pericentric nucleosomes in other species

Metformin reveals a mitochondrial copper addiction of mesenchymal cancer cells

International audienceThe clinically approved drug metformin has been shown to selectively kill persister cancer cells through mechanisms that are not fully understood. To provide further mechanistic insights, we developed a drug surrogate that phenocopies metformin and can be labeled in situ by means of click chemistry. Firstly, we found this molecule to be more potent than met-formin in several cancer cell models. Secondly, this technology enabled us to provide visual evidence of mitochondrial targeting with this class of drugs. A combination of fluorescence microscopy and cyclic voltammetry indicated that metformin targets mitochondrial copper, inducing the production of reactive oxygen species in this organelle, mitochondrial dysfunc-tion and apoptosis. Importantly, this study revealed that mitochondrial copper is required for the maintenance of a mesenchymal state of human cancer cells, and that metformin can block the epithelial-to-mesenchymal transition, a biological process that normally accounts for the genesis of persister cancer cells, through direct copper targeting

Climate Change in Rwanda: The Observed Changes in Daily Maximum and Minimum Surface Air Temperatures during 1961-2014

Rwanda has experienced high temperature rising phenomena over the last decades and hence, highly vulnerable to climate change. This paper examined the spatial and temporal variations of daily maximum and minimum surface air temperature (Tmin and Tmax) and diurnal temperature range (DTR). It studied variables at monthly, seasonal and annual time-scales from 1961 to 2014. The study applied various statistical methods such as ordinary least-square fitting, Mann-Kendall, Sen' slope and Sequential Mann-Kendall statistical test to the new reconstructed ENACTS dataset that cover the period from 1983 to 2014 while pre-1983s recorded data from 24 meteorological stations have been added to complete the lengthiness of ENACTS data. The January to February season did not show a significant trend at seasonal time-scales. The authors decided only to consider March-to-May, June-to-August and October-to-December seasons for further analyses. Topography impacts on temperature classified stations into three regions: region one (R1) (1,000-1,500 m), region two (R2) (1,500-2,000 m) and region three (R3) (>= 2,000 m). With high confidence, the results indicate a significant positive trend in both Tmin and Tmax in all three regions during the whole study period. However, the magnitude rate of temperatures change is different in three regions and it varies in seasonal and annual scale. The spatial distributions of Tmax and Tmin represent a siginificant warming trend over the whole country notably since the early 1980s. Surprisingly, Tmin increased at a faster rate than Tmax in R3 (0.27 vs. 0.07 degrees C/decade in March-to-May) and (0.29 vs. 0.04 degrees C/decade in October-to-December), resulting in a significant decrease in the DTR. This is another confirmation of warming in Rwanda. The mutation test application exhibited most of the abrupt changes in the seasonal and annual Tmax and Tmin trends between 1984 and 1990. The present work mainly focus on the spatial and temporal variability of Tmin, Tmax and DTR in Rwanda and their relationship with elevation change, leaving a gap in other potential cause factors explored in the future

Correction: Metformin reveals a mitochondrial copper addiction of mesenchymal cancer cells.

[This corrects the article DOI: 10.1371/journal.pone.0206764.]

A Critical Role for Toxoplasma gondii Vacuolar Protein Sorting VPS9 in Secretory Organelle Biogenesis and Host Infection

International audienceAccurate sorting of proteins to the three types of parasite-specific secretory organelles namely rhoptry, microneme and dense granule in Toxoplasma gondii is crucial for successful host cell invasion by this obligate intracellular parasite. Despite its tiny body architecture and limited trafficking machinery, T. gondii relies heavily on transport of vesicles containing proteins, lipids and important virulence-like factors that are delivered to these secretory organelles. However, our understanding on how trafficking of vesicles operates in the parasite is still limited. Here, we show that the T. gondii vacuolar protein sorting 9 (TgVps9), has guanine nucleotide exchange factor (GEF) activity towards Rab5a and is crucial for sorting of proteins destined to secretory organelles. Our results illuminate features of TgVps9 protein as a key trafficking facilitator that regulates protein maturation, secretory organelle formation and secretion, thereby ensuring a primary role in host infection by T. gondii. Toxoplasma gondii is an important food and waterborne pathogen causing toxoplasmosis, a usually mild disease in immunocompetent humans that can turn into a major threat in immunocompromised patients and during primary infection of pregnant woman. T. gondii is a member of the Apicomplexa, a phylum of numerous medically important parasites causing life-threatening diseases in human and animals worldwide. The phylum is typified by specific secretory organelles called rhoptries, micronemes and dense granules that are essential for host cell invasion and host pathway modulation. In Toxoplasma, rhoptries contain two groups, termed rhoptry (ROP) and rhoptry neck (RON), of effector proteins some of which are virulence factors; whereas micronemes secrete MIC proteins that are involved in parasite gliding, host cell attachment and invasion 1,2. After invasion, dense granules discharge GRA proteins involved in parasitophorous vacuole (PV) formation and in hijacking host cell gene expression and metabolism 3. Despite having a single cell architecture, the parasite relies on active and abundant vesicle and protein trafficking. T. gondii and likely all Apicomplexa have reutilized classical endosomal and endocytic trafficking pathways more typical of higher eukaryotes towards building specialized secretory organelles that release parasite effectors to interplay with host cell signaling pathways as a way to take control over host immunity and ultimately to promote long-term parasitism 4–8. It is now well established that apicomplexan parasites operate an unconventional endosome-like system (ELC) to traffic proteins from the Golgi apparatus to rhoptries and micronemes 6–8. However, the mechanisms involved in endosome-like vesicle formation and delivery to the aforementioned organelles in general remain elusive. In mammalian cells, the endosomal system is used for the uptake of plasma membrane-associated components, which after passage through Rab5-positive early endosomes (EE) enter either Rab11A-positive recycling endosomes to return to the plasma membrane, or Rab7-positive late endosomes to be delivered to lysosomes (LE) 9

A MORC-driven transcriptional switch controls Toxoplasma developmental trajectories and sexual commitment

International audienc