Eric Baranowski

French National Institute for Agriculture, Food, and Environment (INRAE) | INRAE · Animal Health Division, Joint Research Unit 1225 IHAP

Nucleotide second messengers play an important role in bacterial adaptation to environmental changes. Recent evidence suggests that some of these regulatory molecular pathways were conserved upon the degenerative evolution of the wall-less mycoplasmas. We have recently reported the occurrence of a phosphodiesterase (PDE) in the ruminant pathogen My...

Concurrent infections with multiple pathogens are often described in cattle with respiratory illness. However, how the host-pathogen interactions influence the clinical outcome has been only partially explored in this species. Influenza D virus (IDV) was discovered in 2011. Since then, IDV has been detected worldwide in different hosts. A significa...

Mycoplasma bovis est aujourd’hui reconnu comme un agent pathogène responsable de pertes économiques majeures pour la filière bovine à l’échelle mondiale. Les signes cliniques liés à cette infection sont variés. Si les infections respiratoires dominent en Europe, les États-Unis sont principalement confrontés à des cas de mammites. Nos connaissances...

DNA methylations play an important role in the biology of bacteria. Often associated with restriction modification (RM) systems, they are important drivers of bacterial evolution interfering in horizontal gene transfer events by providing a defence against foreign DNA invasion or by favouring genetic transfer through production of recombinogenic DN...

Horizontal gene transfer was long thought to be marginal in Mollicutes, but the capacity of some of these wall-less bacteria to exchange large chromosomal regions has been recently documented. Mycoplasma chromosomal transfer (MCT) is an unconventional mechanism that relies on the presence of a functional integrative conjugative element (ICE) in at...

Bovine respiratory disease (BRD) is among the most prevalent diseases in young cattle. BRD is due to complex interactions between viruses and/or bacteria, most of which have a moderate individual pathogenicity.

Mycoplasmas are parasitic bacteria with streamlined genomes and complex nutritional requirements. Although iron is vital for almost all organisms, its utilization by mycoplasmas is controversial. Despite its minimalist nature, mycoplasmas can survive and persist within the host, where iron availability is rigorously restricted through nutritional i...

Horizontal gene transfer was long thought to be marginal in Mollicutes , but the capacity of some of these wall-less bacteria to exchange large chromosomal regions has been recently documented. Mycoplasma chromosomal transfer (MCT) is an unconventional mechanism that relies on the presence of a functional integrative conjugative element (ICE) in at...

DNA methylation plays an important role in the biology of bacteria. Often associated with restriction-modification (RM) systems, they also provide a defence against foreign DNA. Little is known regarding the methylome of the mycoplasma genus, which encompasses several pathogenic species with small genomes. Here, single molecule real-time (SMRT) and...

Respiratory infections in domestic animals are a major issue for veterinary and livestock industry. Pathogens in the respiratory tract share their habitat with a myriad of commensal microorganisms. Increasing evidence points towards a respiratory pathobiome concept, integrating the dysbiotic bacterial communities, the host and the environment in a...

Bacteria of the Mycoplasma genus are characterized by the lack of a cell-wall, the use of UGA as tryptophan codon instead of a universal stop, and their simplified metabolic pathways. Most of these features are due to the small-size and limited-content of their genomes (580–1840 Kbp; 482–2050 CDS). Yet, the Mycoplasma genus encompasses over 200 spe...

Mycoplasma bovis is an important bovine pathogen causing pneumonia, mastitis, and arthritis and is responsible for major economic losses worldwide. In the absence of an efficient vaccine, control of M. bovis infections mainly relies on antimicrobial treatments, but resistance is reported in an increasing number of countries. To address the situatio...

Mycoplasmas are host-restricted prokaryotes with a nearly minimal genome. To overcome their metabolic limitations, these wall-less bacteria establish intimate interactions with epithelial cells at mucosal surfaces. The alarming rate of antimicrobial resistance among pathogenic species is of particular concern in the medical and veterinary fields. T...

Mycoplasma bovis (M. bovis) es un agente infeccioso de elevada trascendencia a nivel mundial, asociado sobre todo a su participación en el complejo respiratorio bovino en terneros de cebo. No obstante, se trata también de un importante agente etiológico de las mastitis bovinas, donde destaca su gran capacidad de contagio entre vacas en ordeño. Este...

Molecules contributing to microbial cytoadhesion are important virulence factors. In Mycoplasma bovis, a minimal bacterium but an important cattle pathogen, binding to host cells is emerging as a complex process involving a broad range of surface-exposed structures. Here, a new cytoadhesin of M. bovis was identified by producing a collection of ind...

Microbial access to host nutrients is a key factor of the host-pathogen interplay. With their nearly minimal genome, wall-less bacteria of the class Mollicutes have limited metabolic capacities and largely depend on host nutrients for their survival. Despite these limitations, host-restricted mycoplasmas are widely distributed in nature and many sp...

The capacity of Mycoplasmas to engage in horizontal gene transfers has recently been highlighted. Despite their small genome, some of these wall-less bacteria are able to exchange multiple, large portions of their chromosome via a conjugative mechanism that does not conform to canonical Hfr/oriT models. To understand the exact features underlying m...

Horizontal Gene Transfer was long thought to be marginal in Mycoplasma a large group of wall-less bacteria often portrayed as minimal cells because of their reduced genomes (ca. 0.5 to 2.0 Mb) and their limited metabolic pathways. This view was recently challenged by the discovery of conjugative exchanges of large chromosomal fragments that equally...

The discovery of integrative conjugative elements (ICEs) in wall-less mycoplasmas and the demonstration of their role in massive gene flows within and across species have shed new light on the evolution of these minimal bacteria. Of these, the ICE of the ruminant pathogen Mycoplasma agalactiae (ICEA) represents a prototype and belongs to a new clad...

The discovery of integrative conjugative elements (ICEs) in wall-less mycoplasmas and the demonstration of their role in massive gene flows within and across species has shed new light on the evolution of these minimal bacteria. Of these, ICEA of the ruminant pathogen Mycoplasma agalactiae represents a prototype and belongs to a new clade of the Mu...

The class Mollicutes (trivial name "mycoplasma") is composed of wall-less bacteria with reduced genomes whose evolution was long thought to be only driven by gene losses. Recent evidences of massive horizontal gene transfer (HGT) within and across species provided a new frame to understand the successful adaptation of these minimal bacteria to a br...

A lack of knowledge regarding the antigenic properties of Mycoplasma bovis proteins prevents the effective control of bovine infections using immunological approaches. In this study, we detected and characterized a specific and sensitive M. bovis diagnostic biomarker. After M. bovis total proteins and membrane fractions were separated with two dime...

Importance: Many if not all bacteria are able to secrete polysaccharides, either attached to the cell-surface or exported unbound into the extracellular environment. Both types of polysaccharides can play a role in the bacterial-hosts interactions. Mycoplasmas are no exception despite their poor overall metabolic capacity. We showed here thatM. ag...

Unlabelled: Horizontal gene transfer (HGT) is a main driving force of bacterial evolution and innovation. This phenomenon was long thought to be marginal in mycoplasmas, a large group of self-replicating bacteria characterized by minute genomes as a result of successive gene losses during evolution. Recent comparative genomic analyses challenged t...

Mechanisms underlying pathogenic processes in mycoplasma infections are poorly understood, mainly because of limited sequence similarities with classical, bacterial virulence factors. Recently, large-scale transposon mutagenesis in the ruminant pathogen Mycoplasma agalactiae identified the NIF locus, including nifS and nifU, as essential for mycopl...

Horizontal gene transfer (HGT) is a major force of microbial evolution but was long thought to be marginal in mycoplasmas. In silico detection of exchanged regions and of loci encoding putative Integrative Conjugative Elements (ICE) in several mycoplasma genomes challenged this view, raising the prospect of these simple bacteria being able to conju...

We report here the draft genome sequences of Mycoplasma auris and Mycoplasma yeatsii, two species commonly isolated from the external ear canal of Caprinae.

Mycoplasma putrefaciens is one of the etiologic agents of contagious agalactia in goats. We report herein the complete genome sequence of Mycoplasma putrefaciens strain 9231.

We report here the draft genome sequences of Mycoplasma alkalescens, Mycoplasma arginini, and Mycoplasma bovigenitalium. These three species are regularly isolated from bovine clinical specimens, although their role in disease is unclear.

The bacterium Mycoplasma agalactiae is responsible for contagious agalactia (CA) in small domestic ruminants, a syndrome listed by the World Organization for Animal Health and responsible for severe damage to the dairy industry. Recently, we frequently isolated this pathogen from lung lesions of ibexes during a mortality episode in the French Alps....

Mycoplasma agalactiae is an important pathogen of small ruminants, in which it causes contagious agalactia. It belongs to a large group of "minimal bacteria" with a small genome and reduced metabolic capacities that are dependent on their host for nutrients. Mycoplasma survival thus relies on intimate contact with host cells, but little is known ab...

With their reduced genome bound by a single membrane, bacteria of the Mycoplasma species represent some of the simplest autonomous life forms. Yet, these minute prokaryotes are able to establish persistent infection in a wide range of hosts, even in the presence of a specific immune response. Clues to their success in host adaptation and survival r...

Mycoplasmas are minimal bacteria whose genomes barely exceed the smallest amount of information required to sustain autonomous life. Despite this apparent simplicity, several mycoplasmas are successful pathogens of humans and animals, in which they establish intimate interactions with epithelial cells at mucosal surfaces. To identify biological fun...

Engineered RNAs carrying substitutions in the integrin receptor-binding Arg-Gly-Asp (RGD) region of foot-and-mouth disease virus (FMDV) were constructed (aa 141-147 of VP1 capsid protein) and their infectivity was assayed in cultured cells and suckling mice. The effect of these changes was studied in the capsid proteins of two FMDVs, C-S8c1, which...

Microarray technology, originally developed for highly parallel examination of gene expression is regarded as a potential tool in prognosis and diagnosis. With respect to a discrimination analysis, difference as small as one nucleotide base can be distinguished using oligonucleotide-based microarrays. However, this degree of specificity is dependen...

Despite reducing disease, vaccination rarely protects against infection and many pathogens persist within vaccinated animal populations. Circulation of viral pathogens within vaccinated populations may favour the development of vaccine resistance with implications for the evolution of virus pathogenicity and the emergence of variant viruses. The hi...

Motivation: The Alvira tool is a general purpose multiple sequence alignment viewer with a special emphasis on the comparative analysis of viral genomes. This new tool has been devised specifically to address the problem of the simultaneous analysis of a large number of viral strains. The multiple alignment is embedded in a graph that can be explor...

We report that adaptation to infect the guinea pig did not modify the capacity of foot-and-mouth disease virus (FMDV) to kill suckling mice and to cause an acute and transmissible disease in the pig, an important natural host for this pathogen. Adaptive amino acid replacements (I248→T in 2C, Q44→R in 3A, and L147→P in VP1), selected upon serial pas...

Si la vaccination parvient a reduire l'incidence des maladies, il est rare qu'elle confere une protection contre le processus infectieux, de sorte que nombre d'agents pathogenes continuent a circuler au sein des populations d'animaux vaccines. Cette circulation virale risque de favoriser l'apparition d'une resistance aux vaccins, avec des consequen...

Bovine respiratory syncytial virus (BRSV) is able to counteract the alpha/beta interferon (IFN-alpha/beta)-mediated antiviral response for efficient replication in a host-specific manner. Mice models have been developed for experimental infection with human, but not bovine, respiratory syncytial virus strains. Here, it is shown that BRSV can replic...

Foot-and-mouth disease virus (FMDV) variants adapted to BHK-21 cells showed an expanded host-cell tropism that extended to primate and human cell lines. Virus replication in human HeLa and Jurkat cells has been documented by titration of virus infectivity, quantification of virus RNA, expression of a virus-specific non-structural antigen, and seria...

Comprendre la circulation de pestivirus chez les ongulés sauvages est potentiellement important pour expliquer les variations d’effectifs dans ces espèces et pour réaliser les programmes de contrôle des pestiviroses atteignant les animaux domestiques. En 2002 dans les Pyrénées ariégeoises, des symptômes d’amyotrophie et d’amaigrissement, associés à...

Spherical virus capsids are large, multimeric protein shells whose assembly and stability depend on the establishment of multiple non-covalent interactions between many polypeptide subunits. In a foot-and-mouth disease virus capsid, 42 amino acid side chains per protomer are involved in noncovalent interactions between pentameric subunits that func...

We assayed the infectivity of naked foot-and-mouth disease virus (FMDV) RNA by direct inoculation of suckling mice. Our results demonstrate that transcripts generated from full-length cDNA clones were infectious, as was virion-extracted RNA. Interestingly, infectious virus could be recovered from a mutant transcript encoding amino acid substitution...

Infection of an organism or cells in culture with a single infectious genome of an RNA virus results in the prompt formation of a spectrum of mutants, as has been experimentally documented with representatives of the major groups of RNA virus pathogens.1 This fact is critical for the understanding of viral pathogenesis, since it means that a virus...

Foot-and-mouth disease virus evolution is strongly influenced by high mutation rates and a quasispecies dynamics. Mutant swarms are subjected to positive selection, negative selection and random drift of genomes. Adaptation is the result of selective amplification of subpopulations of genomes. The extent of adaptation to a given environment is quan...

The picture beginning to form from genome analyses of viruses, unicellular organisms, and multicellular organisms is that viruses have shared functional modules with cells. A process of coevolution has probably involved exchanges of genetic information between cells and viruses for long evolutionary periods. From this point of view present-day viru...

Foot-and-mouth disease virus (FMDV) is an aphthovirus of the family Picornaviridae and the etiological agent of the economically most important animal disease. As a typical picornavirus, FMD virions are nonenveloped particles of icosahedral symmetry and its genome is a single stranded RNA of about 8500 nucleotides and of positive polarity. FMDV RNA...

Foot-and-mouth disease virus (FMDV) is the causative agent of a disease that constitutes one of the main animal health concerns, as evidenced by the devastating outbreaks that occurred in different areas of the world over the last few years. In this review, we summarise important features of FMDV, aspects of its interactions with cells and hosts as...

Two features of viral quasispecies are reviewed: the presence of memory genomes as minority components of their mutant spectra, and viral extinction due to enhanced mutagenesis. Memory has been documented with several genetic markers of the important animal picornavirus foot-and-mouth disease virus (FMDV). The presence of memory genomes in viral qu...

The duration and fitness dependence of memory in viral quasispecies evolving in cell culture have been investigated using two genetic markers of foot-and-mouth disease virus (FMDV). In lineages of antigenic variant FMDV RED, which reverted to FMDV RGD, memory FMDV RED genomes were detected after 50 infectious cycles, and memory level was fitness de...

The Arg-Gly-Asp (RGD) triplet found in the G-H loop of capsid protein VP1 of foot-and-mouth disease virus (FMDV) is critically involved in the interaction of FMDV with integrin receptors and with neutralizing antibodies. Multiplication of FMDV C-S8c1 in baby hamster kidney 21 (BHK-21) cells selected variant viruses exploiting alternative mechanisms...

The effects of the vaccination of neonatal calves with a glycoprotein E (gE)-negative bovine herpesvirus type 1 (BHV-1) were investigated in naïve and passively immunised calves either with the recommended dose or a 5-fold concentrated one. After inoculation (PI), all calves excreted the virus vaccine except three passively immunised calves inocula...

Evolution of receptor specificity by viruses has several implications for viral pathogenesis, host range, virus-mediated gene targeting, and viral adaptation after organ transplantation and xenotransplantation, as well as for the emergence of viral diseases. Recent evidence suggests that minimal changes in viral genomes may trigger a shift in recep...

The genetic changes selected during the adaptation of a clonal population of foot-and-mouth disease virus (FMDV) to the guinea pig have been analyzed. FMDV clone C-S8c1 was adapted to the guinea pig by serial passage in the animals until secondary lesions were observed. Analysis of the virus directly recovered from the lesions developed by the anim...

We present sequence data from two genomic regions of foot-and-mouth disease virus (FMDV) subjected to several experimental passage regimens. Maximum-likelihood estimates of the nonsynonymous-to-synonymous rate ratio parameter (dN/dS) suggested the action of positive selection on some antigenic sites of the FMDV capsid during some experimental passa...

Foot-and-mouth disease virus (FMDV) was the first animal virus identified. Since then, FMDV has become a model system in animal virology and a considerable amount of information on its structure, biology and vaccinology has been obtained. However, the disease that this virus produces (FMD) still constitutes one of the main animal health concerns. I...

Les méthodes d’épidémiologie moléculaire permettent de comparer les isolats de virus de la fièvre aphteuse en se basant essentiellement sur une partie du gène codant pour la protéine de capside VP1. Des isolats dont les différences entre séquences nucléotidiques sont inférieures à 15% sont considérés comme appartenant au même génotype. Cette méthod...

The consequences of the vaccination of neonatal calves with the widely used live-attenuated temperature-sensitive (ts) bovine herpesvirus type 1 (BHV-1) were investigated. The ts strain established acute and latent infections in all vaccinated calves either with or without passive immunity. Four of seven calves vaccinated under passive immunity bec...

Ribonucleic acid (RNA) viruses evolve as complex distributions of genetically different but closely related variants termed viral quasispecies. The precise genome of a quasispecies cannot be defined, since the consensus genome is an average of many variants. The dynamics of quasispecies has considerable implications for the understanding of the ada...

Biological adaptive systems share some common features: variation among their constituent elements and continuity of core information. Some of them, such as the immune system, are endowed with memory of past events. In this study we provide direct evidence that evolving viral quasispecies possess a molecular memory in the form of minority component...

Ribonucleic acid (RNA) viruses evolve as complex distributions of genetically different but closely related variants termed viral quasispecies. The precise genome of a quasispecies cannot be defined, since the consensus genome is an average of many variants. The dynamics of quasispecies has considerable implications for the understanding of the ada...

Cell surface molecules that can act as virus receptors may exert an important selective pressure on RNA viral quasispecies. Large population passages of foot-and-mouth disease virus (FMDV) in cell culture select for mutant viruses that render dispensable a highly conserved Arg-Gly-Asp (RGD) motif responsible for integrin receptor recognition. Here,...

The function of a loop exposed on the aphthovirus capsid (the G-H loop of protein VP1) has been explored by combining genetic and structural studies with viral mutants. The loop displays a dual function of receptor recognition and interaction with neutralizing antibodies. Remarkably, some amino acid residues play a critical role in both such dispar...