Project description:Disease outbreaks due to the consumption of legume seedlings contaminated with human enteric bacterial pathogens like Escherichia coli O157:H7 and Salmonella enterica are reported every year. We found surface and internal colonization of Medicago truncatula by Salmonella enterica and Escherichia coli O157:H7 even with inoculum levels as low as two bacteria per plant. Expression analyses using microarray revealed that some Medicago truncatula genes were regulated in a similar manner in response to both of these enteric pathogens. Medicago truncatula roots were inoculated with low inoculum levels of two enteric bacteria per plant (E. coli O157:H7 and Salmonella). 10 days post inoculated plants were used for RNA extraction and hybridization on Affymetrix microarrays.
Project description:Disease outbreaks due to the consumption of legume seedlings contaminated with human enteric bacterial pathogens like Escherichia coli O157:H7 and Salmonella enterica are reported every year. We found surface and internal colonization of Medicago truncatula by Salmonella enterica and Escherichia coli O157:H7 even with inoculum levels as low as two bacteria per plant. Expression analyses using microarray revealed that some Medicago truncatula genes were regulated in a similar manner in response to both of these enteric pathogens.
Project description:The enteric nervous system (ENS) controls several intestinal functions including motility and nutrient handling, which can be disrupted by infection-induced neuropathies or neuronal cell death. We investigated possible tolerance mechanisms preventing neuronal loss and disruption in gut motility after pathogen exposure. We found that following enteric infections, muscularis macrophages (MMs) acquire a tissue-protective phenotype that prevents neuronal loss and dysmotility during subsequent challenge with unrelated pathogens. Bacteria-induced neuroprotection relied on activation of gut-projecting sympathetic neurons and signaling via b2-adrenergic receptors (b2AR) on MMs. In contrast, helminth-mediated neuroprotection was dependent on T cells and systemic production of interleukin (IL)-4 and -13 by eosinophils, which induced arginase-expressing MMs that prevented neuronal loss from an unrelated infection located in a different intestinal region. Collectively, these data suggest that distinct enteric pathogens trigger a state of disease- or tissue tolerance that preserves ENS number and functionality.
Project description:Analysis of Bxpc-3 cells treated with serotonin under metabolic stress induced by serum deprivation. Serotonin (5-HT), a well-known neuromodulator with both neurotransmitter and neuroendocrine functions, is also involved in tumorigenesis. Results provide insight into molecular basis of serotonin in pancreatic cancer.
Project description:The serotonin transporter (SERT), a member of the neurotransmitter:sodium symporter family, is responsible for termination of serotonergic signaling by re-uptake of serotonin (5-HT) into the presynaptic neuron. Its key role in synaptic transmission makes it a major drug target, e.g. for the treatment of depression, anxiety and post-traumatic stress. Here, we apply hydrogen-deuterium exchange mass spectrometry to probe the conformational dynamics of human SERT in the absence and presence of known substrates and targeted drugs. Our results reveal significant changes in dynamics in regions TM1, EL3, EL4, and TM12 upon binding co-transported ions (Na+/K+) and ligand-mediated changes in TM1, EL3 and EL4 upon binding 5-HT, the drugs S-citalopram, cocaine and ibogaine. Our results provide a comprehensive direct view of the conformational response of SERT upon binding both biologically relevant substrate/ions and ligands of pharmaceutical interest, thus advancing our understanding of the structure-function relationship in SERT.