Stunt Ranch Santa Monica Mountains Reserve

06 May, 05 AM - 07 May, 10 AM

Purpose of the research project: Biologists have spent centuries cataloguing the diversity of life. However, only in the last few decades have we begun to truly appreciate the diversity of the microbial world, and today explorations of the interactions of this unseen world with the macroscopic one we know so well are in their infancy. Even environments as familiar to us as our own bodies are vast uncharted territories, teeming with microbial life; it has been estimated that microbial cells outnumber human cells by tenfold in the human body. The launch of recent large-scale funding initiatives, in particular the NIH Roadmap?s Human Microbiome Project, is the harbinger of a surge of interest in explicating the complex interactions of microbial communities with their multicellular host environments. Drosophila melanogaster has been a very important model organism for the last century, particularly for research in genetics and development. As a result, genetic tools (inbred lines with a suite of mutations, microarrays, whole genome sequences) have been developed for Drosophila. These tools also make it a great candidate model organism for microbiome studies. The ?microbiome? is the entire consortium of microbes living in and on a multicellular organism. I am particularly interested in the microbes associated with the gut. Symbiotic gut bacteria of insects that subsist on suboptimal diets (like termites, wood-boring beetles, cockroaches, sharpshooters) are well studied, but only a handful of studies have surveyed the microbes associated with Drosophila, and none of those have exclusively surveyed gut tissue. The purpose of this project is to survey the microbes associated with the gut of Drosophila melanogaster and other Drosophila species found in NRS reserves throughout California. To investigate whether microbes play an important role in the physiology of Drosophilids, and thus whether Drosophila can be a good model system for ?microbiomics,? I will ask whether the occurrence of particular gut microbes is best explained by host phylogeny, ecology, geography, or some combination of the three. The NRS offers an ideal backdrop for this type of survey. Drosophila melanogaster is a ubiquitous generalist that is likely to be sampled from each reserve. In addition, each reserve will likely contain a unique assemblage of other species, allowing me to compare the microbial community composition of Drosophila guts found within sites across the various species as well as between sites within D. melanogaster. How is the reserve important to the study? Based on my previous experience collecting from wild populations of Drosophila, I have chosen ten of the NRS reserves that contain habitat preferred by D. melanogaster. The NRS reserves offer a variety of relatively undisturbed habitats accompanied by abundant metadata. Also, I will be able to return to these collecting sites in order to repeat the surveys on a later date. The reserves also offer lab space, which is invaluable when doing dissections in the field. (I know because I have done them before in a tent!) Research objectives, hypotheses (if so stated), experimental design, methods and anticipated significance (as applicable). In particular, please indicate how your research is relevant to the Natural Reserve System. My goal will be to collect Drosophila melanogaster at each reserve. At the same time, I will be collecting many other species of Drosophila. This survey will contribute to the current catalogue of biodiversity in the Natural Reserve System, both for microbial species and the flies that harbor them. All Californian species of Drosophila are attracted to a bait of fermenting bananas. For this study, the bait will be left in a bucket, hanging from a tree, so it will be easy to obtain a diverse collection of flies with minimal impact on the environment. The bait is put out any time during the day, and flies can be collected at dusk and/or dawn of the next day, at which time the traps are removed. Once collected, the flies are transferred to pre-made vials containing sterile water, agar, and food coloring. Flies are left on this minimal, sterile food for 12-24 hours before the guts are dissected. During this time, the flies ingest the colored water and excrete the bait (or whatever they?ve been eating.) This will enrich our gut samples for microbes that are permanent residents in the guts, rather than transient species found on their food. The food coloring makes the guts very easy to visualize for dissection. Before dissection, the surface of the flies is sterilized with a series of washes. After dissection, the guts are stored in liquid nitrogen until the samples can all be processed. I will travel with a portable dissecting microscope, a dewer of liquid nitrogen in which to store the dissected gut samples, and all other supplies and reagents. I will need to use the lab space at the reserve (when available) to sort the flies and do the dissections. This typically takes 2-6 hours, depending on the number of species and the total number of flies. I will attempt to collect 10 individuals of each species. When I return to the lab at UC Davis, I will extract DNA from the gut samples and use PCR with primers specific to the bacterial 16S rRNA gene, followed by sequencing of those PCR products, to survey the microbes that are present. The bacterial 16S sequences will be compared to a large database of 16S sequences to determine which microbes are present in each sample. Software designed for the comparison of 16S PCR libraries will be used to describe the variation in microbial community composition among reserves and between species in each reserve.

Visit #13776 @Stunt Ranch Santa Monica Mountains Reserve

Approved

Under Project # 8974 | Research

A survey of the microbes associated with California Drosophila species.

graduate_student - University of California, Davis

Reservation Members(s)

Jenna Morgan May 6 - 7, 2008 (2 days)

Reserve Resources(s) | Create Invoice

Day Use Only 1 May 6 - 7, 2008