Biology subjects

Stintzi, A.

Publications and source records attributed to Stintzi, A..

3 recordsLinked to original sources

bioRxiv2019

An in vitro model maintaining taxon-specific functional activities of the gut microbiome

The gut microbiome is a new target for therapeutics. In vitro high-throughput culture models could provide time-and-cost saving solutions to discover microbiome responses to drugs. Unfortunately, there has been no report of in vitro models capable of maintaining functional and compositional profiles resembling the in vivo gut microbiome. Here, we developed and validated a high-throughput culturing model named Mipro to maintain individuals microbiomes. The Mipro model quintupled viable bacteria count while maintained the functional and compositional profiles of individuals gut microbiomes. Comparison of taxon-specific functions between pre -and-post culture microbiomes showed Pearsons correlation coefficient r of 0.83 {+/-} 0.03. Moreover, the Mipro model also exhibited a high degree of in vitro - in vivo correlation (Pearsons r of 0.68 {+/-} 0.09) in microbial responses to metformin in mice fed a high-fat diet. Mipro provides a highly simulated gut microbiome for high-throughput investigation of drug-microbiome interactions.

microbiology↗

bioRxiv2019

RapidAIM: A culture- and metaproteomics-based Rapid Assay of Individual Microbiome responses to drugs

The gut microbiome has been associated with a growing list of diseases. Drugs and other compounds can affect the microbiome, but our understanding of drug-induced changes in individual microbiomes is limited due to a lack of rapid and effective high-throughput assay methods. We developed an approach named Rapid Assay of Individual Microbiome (RapidAIM) to screen xenobiotics against individual microbiomes. RapidAIM was evaluated by testing 43 compounds against five individual microbiomes using a metaproteomic approach. We show that our workflow enables quantitative profiling of the microbiome. The tested compounds significantly affected overall microbiome abundance, microbiome composition and functional pathways at multiple taxonomic levels. The microbiome responses to berberine, metformin, diclofenac, fructooligosaccharide and most antibiotics were consistent among most individuals. Interestingly, most of our tested NSAIDs, statins, and histamine-2 blockers induced strong and individually distinct responses. Our workflow offers an effective solution to systematically study the effects of many different compounds on individual microbiomes.

microbiology↗

bioRxiv2019

The systemin signaling cascade as derived from phosphorylation time courses under stimulation by systemin and its inactive Thr17Ala (A17) analog

Systemin is a small peptide with important functions in plant wound response signaling. Although transcriptional responses of systemin action are well described, the precise signaling cascades involved in its perception and signal transduction are poorly understood at the protein level. Here we use a phosphoproteomic profiling study involving stimulation time courses with systemin and its inactive analogon A17 to reconstruct a systemin-specific kinase/phosphatase signaling network. The time course analysis of systemin-induced phosphorylation patterns revealed early events at the plasma membrane, such dephosphorylation of H+-ATPase, rapid phosphorylation of NADPH-oxidase and Ca2+-ATPase. Later responses involved transient phosphorylation of small GTPases and vesicle trafficking proteins, as well as transcription factors. Based on a correlation analysis of systemin-specific phosphorylation profiles, we predict substrate candidates for 56 systemin specific kinases and 18 phosphatases. Among the kinases are several systemin-specific receptor kinases as well as kinases with downstream signaling functions, such as MAP-kinases. A regulatory circuit for plasma membrane H+-ATPase was predicted and confirmed by in-vitro activity assays. In this regulatory model we propose that upon systemin treatment, H+-ATPase LHA1 is rapidly de-phosphorylated at its C-terminal regulatory residue T955 by phosphatase PLL5, resulting in the alkalization of the growth medium within 2 minutes of systemin treatment. We further propose that the H+-ATPase LHA1 is re-activated by MAP-Kinase MPK2 later in the systemin response. MPK2 was identified with increased phosphorylation at its activating TEY-motif at 15 minutes of treatment and the predicted interaction with LHA1 was confirmed by in-vitro kinase assays. Our data set provides a valuable resource of proteomic events involved in the systemin signaling cascade with a focus on predictions of substrates to systemin-specific kinases and phosphatases.

plant biology↗