A non-human primate model for human norovirus infection.

Norovirus infection can cause gastrointestinal disease in humans. Development of therapies and vaccines against norovirus have been limited by the lack of a suitable and reliable animal model. Here we established rhesus macaques as an animal model for human norovirus infection. We show that rhesus macaques are susceptible to oral infection with human noroviruses from two different genogroups. Variation in duration of virus shedding (days to weeks) between animals, evolution of the virus over the time of infection, induction of virus-specific adaptive immune responses, susceptibility to reinfection and preferential replication of norovirus in the jejunum of rhesus macaques was similar to infection reported in humans. We found minor pathological signs and changes in epithelial cell surface glycosylation patterns in the small intestine during infection. Detection of viral protein and RNA in intestinal biopsies confirmed the presence of the virus in chromogranin A-expressing epithelial cells, as it does in humans. Thus, rhesus macaques are a promising non-human primate model to evaluate vaccines and therapeutics against norovirus disease.

Priority effects alter the colonization success of a host-associated parasite and mutualist.

Priority effects shape the assembly of free-living communities and host-associated communities. However, the current literature does not fully incorporate two features of host-symbiont interactions, correlated host responses to multiple symbionts and ontogenetic changes in host responses to symbionts, leading to an incomplete picture of the role of priority effects in host-associated communities. We factorially manipulated the inoculation timing of two plant symbionts (mutualistic rhizobia bacteria and parasitic root-knot nematodes) and tested how host age at arrival, arrival order, and arrival synchrony affected symbiont colonization success in the model legume Medicago truncatula. We found that host age, arrival order, and arrival synchrony significantly affected colonization of one or both symbionts. Host age at arrival only affected nematodes but not rhizobia: younger plants were more heavily infected than older plants. By contrast, arrival order only affected rhizobia but not nematodes: plants formed more rhizobia nodules when rhizobia arrived before nematodes. Finally, synchronous arrival decreased colonization both symbionts, an effect that depended on host age. Our results demonstrate that priority effects compromise the host's ability to control colonization by two major symbionts and suggest that the role of correlated host responses and host ontogeny in the assembly of host-associated communities deserve further attention.

Using clear plastic CD cases as low-cost mini-rhizotrons to phenotype root traits.

PREMISE: We developed a novel low-cost method to visually phenotype belowground structures in the plant rhizosphere. We devised the method introduced here to address the difficulties encountered growing plants in seed germination pouches for long-term experiments and the high cost of other mini-rhizotron alternatives. METHODS AND RESULTS: The method described here took inspiration from homemade ant farms commonly used as an educational tool in elementary schools. Using compact disc (CD) cases, we developed mini-rhizotrons for use in the field and laboratory using the burclover Medicago lupulina. CONCLUSIONS: Our method combines the benefits of pots and germination pouches. In CD mini-rhizotrons, plants grew significantly larger than in germination pouches, and unlike pots, it is possible to measure roots without destructive sampling. Our protocol is a cheaper, widely available alternative to more destructive methods, which could facilitate the study of belowground phenotypes and processes by scientists with fewer resources.