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International audience; N-terminal derivatization of proteins with permanently positive charged reagent constitutes a viable mass spectrometry bottom-up strategy for systematic confident identification of protein N-termini. Although shotgun nanoLC-ESI-MS/MS approaches are commonly applied in that context by dissociating multiply charged molecular ions upon low energy collision-induced dissociations (CID), we were keen to investigate an alternative sequencing method reckoning on more comprehensive high energy charge remote fragmentations (CRF) available with a MALDI-Tof/Tof instrument. Hence, two tunable activation methods, i. e. metastable laser-induced dissociations (LID) and high energy CID, were applied to several synthetic N-terminal tris(trimethoxyphenyl)phosphonium (TMPP) acetyl peptides and their MS/MS behaviors were compared with low energy CID MS/MS data (LC-ESI-QqTof equipment). The amino acid composition was found to play a significant role in the peptide backbone dissociation pathways of these fixed singly charged ions. Proline, arginine, aspartic acid, glutamic acid, but also surprisingly aliphatic residues were impacting the expected sequence fragmentation pattern.

The Rickettsiales Ehrlichia ruminantium, the causal agent of the fatal tick-borne disease Heartwater, induces severe damage to the vascular endothelium in ruminants. Nevertheless, E. ruminantium-induced pathobiology remains largely unknown. Our work paves the way for understanding this phenomenon by using quantitative proteomic analyses (2D-DIGE-MS/MS, 1DE-nanoLC-MS/MS and biotin-nanoUPLC-MS/MS) of host bovine aorta endothelial cells (BAE) during the in vitro bacterium intracellular replication cycle. We detect 265 bacterial proteins (including virulence factors), at all time-points of the E. ruminantium replication cycle, highlighting a dynamic bacterium–host interaction. We show that E. ruminantium infection modulates the expression of 433 host proteins: 98 being over-expressed, 161 under-expressed, 140 detected only in infected BAE cells and 34 exclusively detected in non-infected cells. Cystoscape integrated data analysis shows that these proteins lead to major changes in host cell immune responses, host cell metabolism and vesicle trafficking, with a clear involvement of inflammation-related proteins in this process. Our findings led to the first model of E. ruminantium infection in host cells in vitro, and we highlight potential biomarkers of E. ruminantium infection in endothelial cells (such as ROCK1, TMEM16K, Albumin and PTPN1), which may be important to further combat Heartwater, namely by developing non-antibiotic-based strategies.

Because the NIS reports hospital discharges rather than unique patients, we were unable to identify patients with multiple hospitalizations or estimate the per-person costs of hepatitis A inpatient care. We were also not able to separately report the costs associated with liver transplantation. Even though using highly sensitive inclusion criteria might have introduced an element of cost over-estimation in some patients incidentally diagnosed with hepatitis A while admitted for other conditions, our results almost certainly underestimate hospitalization costs associated with the ongoing hepatitis A outbreaks because NIS does not include hospital-based physician fees. Moreover, the national $306.8 million estimate does not account for outpatient visits , emergency department visits that did not result in an admission to the same hospital, lost productivity , out-of-pocket costs to patients or their informal caregivers, or public health costs associated with the hepatitis A outbreaks, further reinforcing the conservative nature of this estimate. Given the high proportion of hospitalized patients during the ongoing hepatitis A outbreaks, we estimated the average hepatitis A-related hospitalization costs to highlight the preventable economic burden of these outbreaks on healthcare systems and state governments. Hepatitis A is a vaccine-preventable disease. Despite longstanding vaccination recommendations for adults at increased risk for hepatitis A virus infection or adverse consequences of infection, self-reported adult hepatitis A vaccination coverage with >2 doses was only 10.9% for persons >19 years of age in 2017 (6). Our findings underscore the importance of improving hepatitis A vaccination coverage among at-risk adults, in accordance with Advisory Committee on Immunization Practices recommendations (7).

Education is one of the most important cultural values in the Chinese mindset. Business schools have been developing rapidly in China since 1978 to the extent that they are now offering the largest number of degree programs in the world. As China was isolated for years, business schools were under great pressure to reform their model. After looking at best practices in higher education worldwide, Chinese business schools, whether public, private or corporate, developed in their own ways, building international bridges in the academic world, via international cooperation under the control of the Chinese government.

In terms of lifestyle, free-living bacteria are classified as either oligotrophic/specialist or opportunist/generalist. Heterogeneous marine environments such as coastal waters favour the establishment of marine generalist bacteria, which code for a large pool of functions. This is basically foreseen to cope with the heterogeneity of organic matter supplied to these systems. Nevertheless, it is not known what fraction of a generalist proteome is needed for house-keeping functions or what fraction is modified to cope with environmental changes. Here, we used high-throughput proteomics to define the proteome of Ruegeria pomeroyi DSS-3, a model marine generalist bacterium of the Roseobacter clade. We evaluated its genome expression under several natural environmental conditions, revealing the versatility of the bacterium to adapt to anthropogenic influence, poor nutrient concentrations or the presence of the natural microbial community. We also assayed 30 different laboratory incubations to increase proteome coverage and to dig further into the functional genomics of the bacterium. We established its core proteome and the proteome devoted to adaptation to general cellular physiological variations (almost 50%). We suggest that the other half of its theoretical proteome is the opportunist genetic pool devoted exclusively to very specific environmental conditions.

The human XAB1/ MBDin GTPase and its close homologues form one of the ten phylogenetically distinct families of the SIMIBI ( after signal recognition particle, MinD and BioD) class of phosphate- binding loop NTPases. The genomic context and the partners identified for the archaeal and eukaryotic homologues indicate that they are involved in genome maintenance - DNA repair or replication. The crystal structure of PAB0955 from Pyrococcus abyssi shows that, unlike other SIMIBI class G proteins, these highly conserved GTPases are homodimeric, regardless of the presence of nucleotides. The nucleotide- binding site of PAB0955 is rather rigid and its conformation is closest to that of the activated SRP G domain. One insertion to the G domain bears a strictly conserved GPN motif, which is part of the catalytic site of the other monomer and stabilizes the phosphate ion formed. Owing to this unique functional feature, we propose to call this family as GPN- loop GTPase.

International audience; ORFans are hypothetical proteins lacking any significant sequence similarity with other proteins. Here, we highlighted by quantitative proteomics the TGAM_1934 ORFan from the hyperradioresistant Thermococcus gammatolerans archaeon as one of the most abundant hypothetical proteins. This protein has been selected as a priority target for structure determination on the basis of its abundance in three cellular conditions. Its solution structure has been determined using multidimensional heteronuclear NMR spectroscopy. TGAM_1934 displays an original fold, although sharing some similarities with the 3D structure of the bacterial ortholog of frataxin, CyaY, a protein conserved in bacteria and eukaryotes and involved in iron-sulfur cluster biogenesis. These results highlight the potential of structural proteomics in prioritizing ORFan targets for structure determination based on quantitative proteomics data. The proteomic data and structure coordinates have been deposited to the ProteomeXchange with identifier PXD000402 (http://proteomecentral.proteomexchange.org/dataset/PXD000402) and Protein Data Bank under the accession number 2mcf, respectively.

We present measurements of Ar-broadening parameters for the R(0) and R(7) lines in the fundamental band of13CO at eight temperatures from 80 to 297 K. The broadening parameters are determined by simultaneous least-squares fitting of spectra recorded using a frequency stabilized diode laser spectrometer. The comparison of the broadening parameter values for R(7) derived at room temperature and different pressures from different line profiles shows that an empirical line profile, which takes into account narrowing effects (Dicke narrowing and absorber speed dependence) but neglects any correlation between collisions, is able to describe the observed lines with constant values of the narrowing and broadening parameters over a 10-500 Torr pressure range. Starting from a recent ab initio potential energy surface, theoretical thermally averaged close coupling values of the Ar broadening parameter are calculated for the same temperatures. The comparison between experimental and calculated values shows an overall agreement of 1.5%. © 2003 Elsevier Inc. All rights reserved.

Deinococcus deserti is a desiccation- and radiation-tolerant desert bacterium. Differential RNA sequencing (RNA-seq) was performed to explore the specificities of its transcriptome. Strikingly, for 1,174 (60%) mRNAs, the transcription start site was found exactly at (916 cases, 47%) or very close to the translation initiation codon AUG or GUG. Such proportion of leaderless mRNAs, which may resemble ancestral mRNAs, is unprecedented for a bacterial species. Proteomics showed that leaderless mRNAs are efficiently translated in D. deserti. Interestingly, we also found 173 additional transcripts with a 5'-AUG or 5'-GUG that would make them competent for ribosome binding and translation into novel small polypeptides. Fourteen of these are predicted to be leader peptides involved in transcription attenuation. Another 30 correlated with new gene predictions and/or showed conservation with annotated and nonannotated genes in other Deinococcus species, and five of these novel polypeptides were indeed detected by mass spectrometry. The data also allowed reannotation of the start codon position of 257 genes, including several DNA repair genes. Moreover, several novel highly radiation-induced genes were found, and their potential roles are discussed. On the basis of our RNA-seq and proteogenomics data, we propose that translation of many of the novel leaderless transcripts, which may have resulted from single-nucleotide changes and maintained by selective pressure, provides a new explanation for the generation of a cellular pool of small peptides important for protection of proteins against oxidation and thus for radiation/desiccation tolerance and adaptation to harsh environmental conditions.

Given the ease of whole genome sequencing with next-generation sequencers, structural and functional gene annotation is now purely based on automated prediction. However, errors in gene structure are frequent, the correct determination of start codons being one of the main concerns. Here, we combine protein N termini derivatization using (N-Succinimidyloxycarbonylmethyl)tris(2,4,6-trimethoxyphenyl)phosphonium bromide (TMPP Ac-OSu) as a labeling reagent with the COmbined FRActional DIagonal Chromatography (COFRADIC) sorting method to enrich labeled N-terminal peptides for mass spectrometry detection. Protein digestion was performed in parallel with three proteases to obtain a reliable automatic validation of protein N termini. The analysis of these N-terminal enriched fractions by high-resolution tandem mass spectrometry allowed the annotation refinement of 534 proteins of the model marine bacterium Roseobacter denitrificans OCh114. This study is especially efficient regarding mass spectrometry analytical time. From the 534 validated N termini, 480 confirmed existing gene annotations, 41 highlighted erroneous start codon annotations, five revealed totally new mis-annotated genes; the mass spectrometry data also suggested the existence of multiple start sites for eight different genes, a result that challenges the current view of protein translation initiation. Finally, we identified several proteins for which classical genome homology-driven annotation was inconsistent, questioning the validity of automatic annotation pipelines and emphasizing the need for complementary proteomic data. All data have been deposited to the ProteomeXchange with identifier PXD000337.

Foreword.- Chapter 1. Radioactivity, the First Puzzles.- The "Uranic Rays" of Henri Becquerel.- Polonium and Radium.- Emanation from Thorium.- The Puzzle is Disentangled.- Consecrations and Mourning: the End of an Era.- Chapter 2. A Nucleus at the Heart of the Atom.- Prehistory of the Atom.- 1897: The Electrons Are in the Atom.- The Scattering of alpha Particles Makes It Possible to "See" a Nucleus in the Atom.- A Last Ingredient: Moseley Measures the Charge of the Nucleus in the Atom.- Chapter 3. Quantum Mechanics, the Unavoidable Path.- Branching Off.- An Improbable Beginning.- Niels Bohr: The Quanta Are in the Atom.- 1913-1923: Victories and Setbacks.- 1925: Spin and the Pauli Principle.- Quantum Mechanics.- Chapter 4. A Timid Infancy.- The Atomic Nucleus in 1913.- The Discovery of Isotopes and the Measurement of Masses of Nuclei.- An Enquiry Full of Surprises: ss Radioactivity.- The First Nuclear Reactions.- The Nucleus in 1920 According to Rutherford.- The Rapid Expansion of Experimental Means.- The Atomic Nucleus in 1930.- Chapter 5. 1930-1940: A Dazzling Development.- The Nucleus: A New Boundary.- The Discovery of the Neutron.- Nuclear Theory After the Discovery of the Neutron.- A New Particle: The Positron.- The Birth of Particle Accelerators.- "Charge Independence" of the Nuclear Force.- The Discovery of Artificial Radioactivity.- The School of Rome.- The Great Exodus of Jewish Scientists Under Nazism.- A Proliferation of Theories: Yukawa, Breit and Wigner, Bohr.- The Death of a Giant: Ernest Rutherford.- Hans Bethe Sums Up the Situation in 1936-1937.- The Fission of Uranium.- Chapter 6. The Upheavals of the Second World War.- A Chronology.- The New Face of Physics After the War.- Chapter 7. The Time of Maturity.- New Experimental Means.- Data Accumulate.- The "Shell" Structure of Nuclei.- Elastic Scattering and the "Optical Model".- Direct Nuclear Reactions.- A Collective Behavior.- A Unified Model of the Nucleus.- The Nuclear Force.- Nuclear Matter.- Chapter 8. Where the Narrative Ends.- Glossary.- Bibliography of Cited Books.- Index.

The concept of atoms has existed for centuries, ever since the speculations of Epicurus, until the hesitations of the abbot Nollet. The first experimental manifestations and the conjectures of Dalton, Avogadro and Prout. The atom, a modest point-like object at first, becomes adorned with spectral lines and claims the right to possess an internal structure.

A variety of new accelerators are aimed at creating beams of increasingly energetic particles. New means of detecting and analyzing particles are invented, mostly due to the development of electronic devices which become numerous, varied and flexible, the fruit of apparently unlimited imagination.

Henri Becquerel, while searching for X-rays, discovers a radiation emitted by uranium. The scientific community shows no interest in such a weak and incomprehensible phenomenon with no practical applications.

At the end of the 1950s, nuclear physics is in full bloom. The structure of nuclei is beginning to be understood, and increasingly powerful experimental means probe the nucleus as never before. The economic prosperity as well as strategic considerations, royally endow nuclear physics both humanly and financially. The early years of teeming activity are followed by a period of intensive work devoted to the consolidation and the deepening of our understanding of nuclei.

In the second of the three famous papers, which Niels Bohr wrote in 1913, and in which he described the properties of atoms in terms of quantum physics, he concluded that radioactive phenomena most likely occur in the atomic nucleus

Two refugees, one German, the other Austrian, show the English the extraordinary destructive power which a pure uranium 235 bomb would have. After a tedious start, the United States devote immense resources, both financial and human, in order to build a uranium or plutonium “atomic” bomb. Hiroshima and Nagasaki are destroyed by nuclear fire.

International audience; Wyosine (imG) and its derivatives such as wybutosine (yW) are found at position 37 of phenylalanine-specific transfer RNA (tRNA(Phe)), 3' adjacent to the anticodon in Eucarya and Archaea. In Saccharomyces cerevisiae, formation of yW requires five enzymes acting in a strictly sequential order: Trm5, Tyw1, Tyw2, Tyw3, and Tyw4. Archaea contain wyosine derivatives, but their diversity is greater than in eukaryotes and the corresponding biosynthesis pathways still unknown. To identify these pathways, we analyzed the phylogenetic distribution of homologues of the yeast wybutosine biosynthesis proteins in 62 archaeal genomes and proposed a scenario for the origin and evolution of wyosine derivatives biosynthesis in Archaea that was partly experimentally validated. The key observations were 1) that four of the five wybutosine biosynthetic enzymes are ancient and may have been present in the last common ancestor of Archaea and Eucarya, 2) that the variations in the distribution pattern of biosynthesis enzymes reflect the diversity of the wyosine derivatives found in different Archaea. We also identified 7-aminocarboxypropyl-demethylwyosine (yW-86) and its N4-methyl derivative (yW-72) as final products in tRNAs of several Archaea when these were previously thought to be only intermediates of the eukaryotic pathway. We confirmed that isowyosine (imG2) and 7-methylwyosine (mimG) are two archaeal-specific guanosine-37 derivatives found in tRNA of both Euryarchaeota and Crenarchaeota. Finally, we proposed that the duplication of the trm5 gene in some Archaea led to a change in function from N1 methylation of guanosine to C7 methylation of 4-demethylwyosine (imG-14).

International audience; Deinococcaceae are a family of extremely radiation tolerant bacteria that is currently subjected to numerous studies aimed at understanding the molecular mechanisms for such radiotolerance. To achieve a comprehensive and accurate annotation of Deinococcus deserti genome, we performed an N-terminal-oriented characterization of its proteome. For this, we used a labeling reagent, N-Tris(2,4,6-trimethoxyphenyl)phosphonium acetyl (TMPP), to selectively derivatize protein N-termini. The large scale identification of TMPP-modified Nterminal- most peptides by a shotgun liquid chromatography-tandem mass spectrometry analysis led to the validation of 278 and correction of 73 translation initiation codons in D. deserti genome. In addition, four new genes were detected, three located on the main chromosome and one on plasmid P3. Surprisingly, experimental evidences were obtained indicating that DnaA (the protein involved in the DNA replication initiation process) and RpsL (the S12 ribosomal conserved protein) translation is initiated in Deinococcaceae from non-canonical codons (ATC and CTG, respectively). Such use may be the basis of specific regulation mechanisms affecting replication and translation. We report the use of nonconventional translation initiation codons for two other genes: Deide_03051 and infC. We also analyzed signal peptide cleavages at a genome-wide scale. Based on comparative proteogenomic analysis, we propose a set of 137 corrections to improve Deinococcus radiodurans and Deinococcus geothermalis gene annotations. Some of these corrections affect important genes involved in DNA repair mechanisms such as polA, ligA, and ddrB. Our results demonstrate that predicting translation initiation codons is still difficult and that proteomic-based refinement of genome annotations is necessary. Whether such use of noncanonical translation initiation codons is much more frequent for other bacterial phyla than previously reported or restricted to Deinococcaceae remains to be investigated. Our results demonstrate that predicting translation initiation codons is still difficult for some bacteria and that proteomics-based refinement of genome annotations may be helpful in such cases.

To better understand adaptation to harsh conditions encountered in hot arid deserts, we report the first complete genome sequence and proteome analysis of a bacterium, Deinococcus deserti VCD115, isolated from Sahara surface sand. Its genome consists of a 2.8-Mb chromosome and three large plasmids of 324 kb, 314 kb, and 396 kb. Accurate primary genome annotation of its 3,455 genes was guided by extensive proteome shotgun analysis. From the large corpus of MS/MS spectra recorded, 1,348 proteins were uncovered and semiquantified by spectral counting. Among the highly detected proteins are several orphans and Deinococcus-specific proteins of unknown function. The alliance of proteomics and genomics high-throughput techniques allowed identification of 15 unpredicted genes and, surprisingly, reversal of incorrectly predicted orientation of 11 genes. Reversal of orientation of two Deinococcus-specific radiation-induced genes, ddrC and ddrH, and identification in D. deserti of supplementary genes involved in manganese import extend our knowledge of the radiotolerance toolbox of Deinococcaceae. Additional genes involved in nutrient import and in DNA repair (i.e., two extra recA, three translesion DNA polymerases, a photolyase) were also identified and found to be expressed under standard growth conditions, and, for these DNA repair genes, after exposure of the cells to UV. The supplementary nutrient import and DNA repair genes are likely important for survival and adaptation of D. deserti to its nutrient-poor, dry, and UV-exposed extreme environment., Author Summary D. deserti belongs to the Deinococcaceae, a family of bacteria characterized by an exceptional ability to withstand the lethal effects of DNA-damaging agents, including ionizing radiation, UV light, and desiccation. It was isolated from Sahara surface sands, an extreme and nutrient-poor environment, regularly exposed to intense UV radiation, cycles of extreme temperatures, and desiccation. The evolution of organisms that are able to survive acute irradiation doses of 15,000 Gy is difficult to explain given the apparent absence of highly radioactive habitats on Earth over geologic time. Thus, it seems more likely that the natural selection pressure for the evolution of radiation-resistant bacteria was chronic exposure to nonradioactive forms of DNA damage, in particular those promoted by desiccation. Here, we report the first complete genome sequence of a bacterium, D. deserti VCD115, isolated from hot, arid desert surface sand. Accurate genome annotation of its 3,455 genes was guided by extensive proteome analysis in which 1,348 proteins were uncovered after growth in standard conditions. Supplementary genes involved in manganese import, in nutrient import, and in DNA repair were identified and are likely important for survival and adaptation of D. deserti to its hostile environment.

Pigeon circovirus infection (PiCV) was diagnosed by light and transmission electron microscopy in 15 birds from five lofts in western France. Histopathological findings were suggestive of primary bursotropism of pigeon circovirus, followed by secondary systemic spread from the bursa of Fabricius, particularly to non-bursal lymphoid organs. The last stage of the disease was associated with various secondary (particularly bacterial) infections. In situ detection of apoptosis in the bursa of Fabricius indicated that PiCV was concomitant with an increase in bursal lymphocytic apoptotic events related to viral infection and leading to severe acquired immunosuppression.

International audience; The strategies of multinational firms increasingly rely in Asia Pacific Region on processes of socialising their employees, who are seeking to develop and reinforce a “global” company culture, without endangering the cultures of local subsidiaries. Specialists have coined the term “cross-cultural management”. A role of “company ambassador” is allocated to a new generation of international executives in Asia whose mission will be to play an effective role as interface between head office its the subsidiaries - and between the subsidiaries themselves - once they have been suitably “impregnated” with the company culture and the particular features of different markets. The repeated experience of international mobility that executives live through means that the individual may well be living in conflict with previous identities. It is true to say that nobody stays long in an internationally mobile situation without running the risk of there being strong divergence between the domestic and residential worlds, the life of the community and the world of the company. This article has been written as a result of in-depth research into the way executives of a large French oil company built up their identities and as a result of a study examines intercultural learning based on French expatriates' experience in China. We consider how French expatriates experience China and what imaginary underlies their perception. Analysis of daily socialization and interaction processes shows intercultural competence develops along distinct immersion stages: immersion-adjustment, immersion-comprehension, and immersion-integration. Individually, adjustment and comprehension support intercultural practice. The ultimate immersion stage leads to enlightened pragmatism stemming from “nomadic intelligence”. Where a researcher in the social sciences or a business man might have expected to have found an homogenous international elite, international executives building an “international system”, the heterogeneous nature of the identity strategies of international executives give the lie to the myth of the large company as a space for the irreversible assimilation of its members. At an individual level, being an international executive is a unique way of living the experience abroad, or rather, several different ways of experiencing identity strategies linked to the manipulation of one's ethnicity in a context of significant geographical and functional mobility.

PAB0955 from Pyrococcus abyssi is a prototype of a new Walker-type ATPase/GTPase conserved in archaea and eukaryota but not found in bacteria. PAB0955 has been expressed, purified and crystallized, and it has been shown that this thermostable protein is dimeric in reductive conditions. Crystals have been obtained either without nucleotide or in the presence of GDP or GTPgammaS. Preliminary X-ray crystallographic data up to 2.08 A resolution have been collected from these crystals.

In sequenced genomes, genes belonging to the cluster of orthologous group COG1041 are exclusively, and almost ubiquitously, found in Eukaryota and Archaea but never in Bacteria. The corresponding gene products exhibit a characteristic Rossmann fold, S-adenosylmethionine-dependent methyltransferase domain in the C terminus and a predicted RNA-binding THUMP (thiouridine synthases, RNA methyltransferases, and pseudouridine synthases) domain in the N terminus. Recombinant PAB1283 protein from the archaeon Pyrococcus abyssi GE5, a member of COG1041, was purified and shown to behave as a monomeric 39-kDa entity. This protein (EC 2.1.1.32), now renamed (Pab)Trm-G10, which is extremely thermostable, forms a 1:1 complex with tRNA and catalyzes the adenosylmethionine-dependent methylation of the exocyclic amino group (N(2)) of guanosine located at position 10. Depending on the experimental conditions used, as well as the tRNA substrate tested, the enzymatic reaction leads to the formation of either N(2)-monomethyl (m(2)G) or N(2)-dimethylguanosine (m(2)(2)G). Interestingly, (Pab)Trm-G10 exhibits different domain organization and different catalytic site architecture from another, earlier characterized, tRNA-dimethyltransferase from Pyrococcus furiosus ((Pfu)Trm-G26, also known as (Pfu)Trm1, a member of COG1867) that catalyzes an identical two-step dimethylation of guanosine but at position 26 in tRNAs and is also conserved among all sequenced Eukaryota and Archaea. The co-occurrence of these two guanosine dimethyltransferases in both Archaea and Eukaryota but not in Bacteria is a hallmark of distinct tRNAs maturation strategies between these domains of life.

During development, muscle growth results from the proliferation of satellite cells (SC) and their fusion with fibers. Several studies revealed heterogeneity of SC population notably based on the proliferation rate. Here, we examined the SC characteristics of turkey skeletal muscles in terms of proliferation and more specifically fusion, to define if the ability of these cells to fuse may represent a distinct characteristic between them and could be directly associated with their proliferation properties. Freshly extracted SC were plated in clonal condition and their proliferation rate was assessed 11 days later. To investigate the SC fusion behavior, in vitro and in vivo approaches were developed. Highly and slowly proliferative SC were initially labeled with a nuclear beta-galactosidase (beta-Gal) activity and co-cultured with differentiated primary cultures. After 5 days, distribution of beta-Gal positive (beta-Gal+) nuclei was examined. Also, the two labeled SC types were transplanted into different muscles in autologous model. One week later, number of beta-Gal+ nuclei per fiber and diameter of fibers displaying beta-Gal+ nuclei were determined. In vitro, we showed that SC from turkey skeletal muscle are present as a heterogeneous population in terms of proliferation. Examination of their fusion properties in vitro as well as in vivo revealed that highly proliferative SC exclusively exhibited fusion with differentiated myotubes or myofibers, whereas slowly proliferative SC mainly fused together. Collectively, these data demonstrate for the first time that SC with different proliferation rate also intrinsically differ in their fusion potential, suggesting distinct roles for these sub-populations in muscle growth.

International audience; Although coenzymeA (CoA) is essential in numerous metabolic pathways in all living cells, molecular characterization of the CoA biosynthetic pathway in Archaea remains undocumented. Archaeal genomes contain detectable homologues for only three of the five steps of the CoA biosynthetic pathway characterized in Eukarya and Bacteria. In case of phosphopantetheine adenylyltransferase (PPAT) (EC 2.7.7.3), the putative archaeal enzyme exhibits significant sequence similarity only with its eukaryotic homologs, an unusual situation for a protein involved in a central metabolic pathway. We have overexpressed in Escherichia coli, purified, and characterized this putative PPAT from the hyperthermophilic archaeon Pyrococcus abyssi (PAB0944). Matrixassisted laser desorption ionization-time of flight mass spectrometry and high performance liquid chromatography measurements are consistent with the presence of a dephospho-CoA (dPCoA) molecule tightly bound to the polypeptide. The protein indeed catalyzes the synthesis of dPCoA from 4-phosphopantetheine and ATP, as well as the reverse reaction. The presence of dPCoA stabilizes PAB0944, as it induces a shift from 76 to 82°C of the apparent T m measured by differential scanning microcalorimetry. Potassium glutamate was found to stabilize the protein at 400 mM. The enzyme behaves as a monomeric protein. Although only distantly related, secondary structure prediction indicates that archaeal and eukaryal PPAT belong to the same nucleotidyltransferase superfamily of bacterial PPAT. The existence of operational proteins highly conserved between Archaea and Eukarya involved in a central metabolic pathway challenge evolutionary scenarios in which eukaryal operational proteins are strictly of bacterial origin.

Erythematous macules, nonpalpable and palpable purpura, and flaccid pustules developed in a 59-year-old man with acute lymphocytic leukemia 8 days after reinduction chemotherapy with cytosine arabinoside and daunorubicin. Tissue and blood cultures grew Fusarium proliferatum, and a skin biopsy specimen revealed fungal vasculitis. Anemia and muscle weakness accompanied the disseminated infection, for which the patient received granulocyte transfusions and amphotericin B, ketoconazole, rifampin, and griseofulvin. Skin lesions and fungemia resolved with recovery of the bone marrow, and 51 days after the completion of his chemotherapy he returned home. If promptly recognized and aggressively treated, disseminated fusariosis is responsive to therapy. Infection with Fusarium species should be suspected in profoundly neutropenic patients in whom disseminated palpable purpura and myositis develop concomitantly.