Cecilia Milano de Tomasel

Responses of a desert nematode community to changes in water availability

The most recent climate models unequivocally predict a strong drying trend for the southwestern USA within the next century. Soil nematodes are a highly important component of desert ecosystem functioning, but rely on water films for movement. However, it is currently poorly understood how different trophic groups of nematodes respond to chronic presses as well as short-lived pulses of altered water availability, especially in arid systems where such changes are expected to have the greatest impact. The aim of this study was to assess the effects of both instantaneous and long-term variation in water availability on desert soil nematode trophic groups. We hypothesized that nematode abundance would respond positively to both short- and long-term increases in moisture. Based on the ecology of the different trophic groups we further made predictions about their relative rates of response. We increased or decreased precipitation from ambient levels in the Chihuahuan Desert for four consecutive years and sampl...

Culturing the Antarctic nematode Plectus murrayi.

The Antarctic terrestrial nematode Plectus murrayi is an excellent model organism for the study of stress response mechanisms in various types of environmental conditions. In this procedure, we describe a method for culturing P. murrayi extracted from soil and sediment samples from the McMurdo (MCM) Dry Valleys of Antarctica. Nematodes are cultured on sand agar plates and incubated at various temperatures, and feed on bacteria growing on the agar media. They can be subcultured and stored at 15°C for >2 mo. This method is easy to carry out and can produce nematodes in quantities sufficient for ecological and molecular studies.

The Antarctic Nematode Plectus murrayi: An Emerging Model to Study Multiple Stress Survival

The genus Plectus is one of the most widely distributed and common nematode taxa of freshwater and terrestrial habitats in the world, and is of particular interest because of its phylogenetic position relative to the origin of the Secernentean radiation. Plectus murrayi, a bacteria-feeding nematode, inhabits both semi-aquatic and terrestrial biotopes in the Antarctic McMurdo Dry Valleys (MCM), where its distribution is limited by organic carbon and soil moisture. Plectus nematodes from the MCM can survive extreme desiccation, freezing conditions, and other types of stress. Ongoing investigations of the physiological and molecular aspects of the stress biology of P. murrayi, along with the availability of genomic resources, will likely establish this nematode as an excellent invertebrate model system for studies of extreme environmental survival, and may provide a valuable source of genomic resources for comparative studies in other organisms. Moreover, because P. murrayi and Caenorhabditis elegans share a most recent common ancestor with the rest of the Secernentea, and given the ability of P. murrayi to be cultured at lower temperatures compared to C. elegans, P. murrayi could also be an emerging model system for the study of the evolution of environment-sensitive (stress response) alleles in nematodes.