Project description:This experiment exploits the life-cycle of Strongyloides ratti, which is a parasitic nematode of brown rats that exhibits three adult stages within its life-cycle - parasitic females, freeliving females and free-living males. We use a cDNA microarray to examine patterns of (i) gender-biased gene expression by contrasting free-living females against free-living males, and (ii) parasitic-biased expression by contrasting parasitic females against free-living females. Of the 3688 distinct transcripts represented on our array, 20% exhibited male-biased expression 19% exhibit female-biased expression, 11% exhibit parasitic-biased expression and 8% exhibit free-living-biased expression. Among the top responding genes, an orthologue of major sperm protein is upregulated in males, distinct aspartic protease orthologues are upregulated in either parasitic or in free-living females, and orthologues of hsp-17 chaperone are upregulated in parasitic females. Upon a global analysis of gene expression, we find that female-biased expression is associated with genes involved in reproductive processes and larval development, that male-biased expression is associated with genes involved in metabolism, and that free-living biased expression is associated with genes involved in regulation of body fluids and response to external stimulus. The association of gene ontology with parasite-biased expression is less clear. Our results provide an initial gene expression analysis of gender- and parasite-biased expression in S. ratti, may be more generally applicable to other parasitic nematodes, and may help to refine the search for novel drug or vaccine targets against parasitic nematodes.
Project description:In previous studies we have shown that the two adult females morphs of S. ratti have very different lifespans. This experiment was designed to try to identify differentially expressed genes in these two adult morphs that may account for these differing lifespans. The genes expressed by S. ratti parasitic females at day 6 p.i. were compared to the genes expressed by S. ratti free living females at 3 days 19 degrees C. This comparison was done using a microarray chip that is spotted with PCR fragments from the libraries that were generated from parasitic females extracted at day 6 and day 15 p.i., and a microarray chip that is spotted with PCR fragments from the libraries that were generated from free-living larval stages L1, L2 and infective L3s and from free-living males and females.
Project description:SNP genotyping was used to determine if the free living Highland Wild dogs of Papua, Indonesia are the ansestors of captive New Guinea Singing Dogs.
Project description:Periods of social instability can elicit adaptive phenotypic plasticity to promote success in future competition. However, the underlying molecular mechanisms have primarily been studied in captive and lab-reared animals, leaving uncertainty as to how natural competition among free-living animals affects gene activity. Here, we experimentally generated social competition among wild, cavity-nesting female birds (tree swallows, Tachycineta bicolor). After territorial settlement, we reduced the availability of key breeding resources (i.e., nest boxes), generating heightened competition; within 24 hr we reversed the manipulation, causing aggressive interactions to subside. We sampled females during the peak of competition and 48hr after it ended, along with date-matched controls. We measured transcriptomic and epigenomic responses to competition in two socially relevant brain regions (hypothalamus and ventromedial telencephalon). Gene network analyses suggest that processes related to energy mobilization and social aggression (e.g., dopamine synthesis) were upregulated during competition, the latter of which persisted 2 days after competition had ended. Cellular maintenance processes were also downregulated after competition. Competition additionally altered methylation patterns, particularly in pathways related to hormonal signaling, which appeared transcriptionally poised to respond to future competition . Thus, experimental competition among free-living animals shifts gene expression in ways that may facilitate the demands of competition at the expense of self-maintenance. Further, some of these effects persisted after competition ended, demonstrating the potential for epigenetic biological embedding of the social environment in ways that could “prime” individuals for success in future social instability.
Project description:Mesorhizobium huakuii 7653R is an M-NM-1-proteobacterium that occurs either in a nitrogen-fixing symbiosis with its host plant, A. sinicus, or free-living in the soil. Investigation of whole genome gene expression level changes in Bacteroids compared to the free-living cells. Understand how M. huakuii 7653R responds to alterations in its environment and to the physiological changes that occur during bacteroid differentiation. Examination of mRNA levels in free-living cells and bacteroids at 32 days postinoculation
Project description:Free-living bacteria were grown on succinae ammonia AMS and gene expression was compared to free-living bacteria grown on glucose ammonia AMS.
Project description:Mesorhizobium huakuii 7653R is an α-proteobacterium that occurs either in a nitrogen-fixing symbiosis with its host plant, A. sinicus, or free-living in the soil. Investigation of whole genome gene expression level changes in Bacteroids compared to the free-living cells. Understand how M. huakuii 7653R responds to alterations in its environment and to the physiological changes that occur during bacteroid differentiation.