Disentangling the effect of host genetics and gut microbiota on resistance to an intestinal parasite.

Resistance to infection is a multifactorial trait, and recent work has suggested that the gut microbiota can also contribute to resistance. Here, we performed a fecal microbiota transplant to disentangle the contribution of the gut microbiota and host genetics as drivers of resistance to the intestinal nematode Heligmosomoides polygyrus. We transplanted the microbiota of a strain of mice (SJL), resistant to H.

Early -induced inflammation does not accelerate aging in mice.

Aging is associated with a decline of performance leading to reduced reproductive output and survival. While the antagonistic pleiotropy theory of aging has attracted considerable attention, the molecular/physiological functions underlying the early-life benefits/late-life costs paradigm remain elusive. We tested the hypothesis that while early activation of the inflammatory response confers benefits in terms of protection against infection, it also incurs costs in terms of reduced reproductive output at old age and shortened longevity.

Early life infection and host senescence.

Advanced age is often associated with a chronic inflammatory status and inflammatory diseases. It has been suggested that exposure to infectious agents that stimulate the inflammatory response at early ages might have carry over effects in terms of accelerated senescence and increased mortality at late ages. However, not all pathogens and parasites have pro-inflammatory effects.

Life history adjustments to intestinal inflammation in a gut nematode.

Many parasitic nematodes establish chronic infections. This implies a finely tuned interaction with the host immune response in order to avoid infection clearance. Although a number of immune interference mechanisms have been described in nematodes, how parasites adapt to the immune environment provided by their hosts remains largely unexplored.

Microbiota Diversity Within and Between the Tissues of Two Wild Interbreeding Species.

Understanding the role of microbiota as reproductive barriers or sources of adaptive novelty in the fundamental biological phenomenon of speciation is an exciting new challenge necessitating exploration of microbiota variation in wild interbreeding species. We focused on two interbreeding cyprinid species, Chondrostoma nasus and Parachondrostoma toxostoma, which have geographic distributions characterized by a mosaic of hybrid zones. We described microbiota diversity and composition in the three main teleost mucosal tissues, the skin, gills and gut, in the parental parapatric populations.

Plastic and micro-evolutionary responses of a nematode to the host immune environment.

Parasitic organisms have to cope with the defences deployed by their hosts and this can be achieved adopting immune evasion strategies or optimal life history traits according to the prevailing pattern of immune-mediated mortality. Parasites often encounter variable immune environments both within and between hosts, promoting the evolution of plastic strategies instead of fixed responses. Here, we explored the plasticity and micro-evolutionary responses of immunomodulatory mechanisms and life history traits to the immune environment provided by the host, using the parasitic nematode Heligmosomoides polygyrus.

Microevolution of bank voles (Myodes glareolus) at neutral and immune-related genes during multiannual dynamic cycles: Consequences for Puumala hantavirus epidemiology.

Understanding how host dynamics, including variations of population size and dispersal, may affect the epidemiology of infectious diseases through ecological and evolutionary processes is an active research area. Here we focus on a bank vole (Myodes glareolus) metapopulation surveyed in Finland between 2005 and 2009. Bank vole is the reservoir of Puumala hantavirus (PUUV), the agent of nephropathia epidemica (NE, a mild form of hemorrhagic fever with renal symptom) in humans.

Helminth Interaction with the Host Immune System: Short-Term Benefits and Costs in Relation to the Infectious Environment.

Chronic infections imply that the parasite and the host immune system closely interact for a long time without a fatal outcome. Environmental changes encountered by hosts and parasites, such as coinfections, can deeply affect the stability of this apparent equilibrium. Our study aimed to determine the effect of the infectious environment on the costs and benefits of chronic infection with the gut nematode Heligmosomoides polygyrus in mice.

Reaction norms of host immunity, host fitness and parasite performance in a mouse--intestinal nematode interaction.

The outcome of the encounter between a host and a parasite depends on the synergistic effects of the genetics of the two partners and the environment (sensulato) where the interaction takes place. Reaction norms can depict how host and parasite traits vary across environmental ranges for different genotypes. Here, we performed a large scale experiment where three strains of laboratory mice (SJL, BALB/c and CBA) were infected with four doses of the intestinal nematode Heligmosomoides polygyrus.

Candidatus Neoehrlichia mikurensis in bank voles, France.

To further assess the geographic occurrence, possible vectors, and prevalence of Candidatus Neoehrlichia mikurensis, we analyzed spleen tissues from 276 voles trapped close to human settlements in France; 5 were infected with the organism. Sequencing showed the isolates carried the same genotype as the bacteria that caused disease in humans and animals elsewhere in Europe.

Concomitant influence of helminth infection and landscape on the distribution of Puumala hantavirus in its reservoir, Myodes glareolus.

Background: Puumala virus, the agent of nephropathia epidemica (NE), is the most prevalent hantavirus in Europe. The risk for human infection seems to be strongly correlated with the prevalence of Puumala virus (PUUV) in populations of its reservoir host species, the bank vole Myodes glareolus. In humans, the infection risks of major viral diseases are affected by the presence of helminth infections.

SESAME (SEquence Sorter & AMplicon Explorer): genotyping based on high-throughput multiplex amplicon sequencing.

Summary: Characterizing genetic diversity through genotyping short amplicons is central to evolutionary biology. Next-generation sequencing (NGS) technologies changed the scale at which these type of data are acquired. SESAME is a web application package that assists genotyping of multiplexed individuals for several markers based on NGS amplicon sequencing.

Tnf-α expression and promoter sequences reflect the balance of tolerance/resistance to Puumala hantavirus infection in European bank vole populations.

The tumor necrosis factor-alpha (TNF-α) influences the ability to limit parasite infection but its over-production might result in inflammatory disorders. The level of Tnf-α gene expression could thus mediate a balance of tolerance/resistance to infections. This study focused on Puumala hantavirus (PUUV) infection in its rodent host, the bank vole (Myodes glareolus).

Associations between MHC genes and Puumala virus infection in Myodes glareolus are detected in wild populations, but not from experimental infection data.

We analysed the influence of MHC class II Dqa and Drb genes on Puumala virus (PUUV) infection in bank voles (Myodes glareolus). We considered voles sampled in five European localities or derived from a previous experiment that showed variable infection success of PUUV. The genetic variation observed in the Dqa and Drb genes was assessed by using single-strand conformation polymorphism and pyrosequencing methods, respectively.

A 454 multiplex sequencing method for rapid and reliable genotyping of highly polymorphic genes in large-scale studies.

Background: High-throughput sequencing technologies offer new perspectives for biomedical, agronomical and evolutionary research. Promising progresses now concern the application of these technologies to large-scale studies of genetic variation. Such studies require the genotyping of high numbers of samples.