Deletion of galactarate utilization genes rendered S.
Typhimurium is induced by hydrogen, a fermentation product of the gut microbiota 8. Expression of the gudT ygcY gudD STM2959 operon in S. 1c), which encodes proteins involved in galactarate uptake and catabolism 7. Typhimurium strain lacking the gudT ygcY gudD STM2959 operon ( gudT-STM2959 mutant, Extended Data Fig. To investigate whether this nutrient is normally available to promote growth in mucus, we constructed a S. We therefore investigated the origin of galactarate in the intestine.Ĭonsistent with the idea that galactarate is a xenobiotic, the concentration of this sugar in mouse chow was very low, as suggested by gas chromatography/mass spectrometry (GC/MS) measurements ( Extended Data Fig. However, the biological significance of this association is not clear, because galactarate is a xenobiotic that is not normally produced by mammals or expected to be present within the diet. While 98.2% of serovars associated with gastrointestinal infections can ferment this carbon source, only 15.4% of serovars associated with extraintestinal disease test positive for this reaction 6 ( Extended Data Fig. Galactarate fermentation is one of the biochemical reactions used to differentiate members of the genus Salmonella into serovars. enterica serovars causing gastrointestinal disease 5. Our results identify a host-mediated oxidation of carbohydrates in the gut as a novel mechanism for post-antibiotic pathogen expansion.Ī recent in silico analysis suggests that pathways involved in galactarate uptake and catabolism are associated with S. Typhimurium utilized galactarate and glucarate within the gut lumen of streptomycin pre-treated mice and genetic ablation of the respective catabolic pathways reduced its competitiveness. By elevating expression of the gene encoding inducible nitric oxide synthase (iNOS) in the cecal mucosa, streptomycin treatment increased post-antibiotic availability of the oxidation products galactarate and glucarate in the murine cecum. Here we show that host-mediated oxidation of galactose and glucose promotes post-antibiotic expansion of S. enterica serovars are not fully resolved. However, the mechanisms by which streptomycin treatment drives an expansion of S. These antibiotic-induced changes in the gut microbiota can be studied in mice, where the disruption of a balanced microbial community by treatment with streptomycin leads to an expansion of S. Antibiotic usage elevates the risk of contracting gastroenteritis caused by Salmonella enterica serovars 1, increases the duration for which patients shed the pathogen in their feces and may on occasion produce a bacteriologic and symptomatic relapse 2, 3.
#Pre gibson tobias serial numbers serial numbers#
Basses below the serial number 2044 were built in the California factory headed-up by Michael Tobias serial numbers after that were produced by Gibson with a transition period in which Tobias worked with Gibson and continued to produce basses.Changes in the gut microbiota may underpin many human diseases, but the mechanisms that are responsible for altering microbial communities remain poorly understood. Michael Tobias left the company in 1992 to found Michael Tobias Design which produces a line of hand-made basses similar in spirit to the older Tobias basses. The first Tobias bass under Gibson ownership bore the serial number 1094. In 1990, Gibson Guitar Corporation purchased Tobias and moved production to Nashville. The first serial number was 0178, instead of the usual 0001, as a reference to the month the first bass was completed, January 1978. Tobias basses also were among the first to feature an asymmetrical neck, a design where the neck is thinner on the lower side than the upper. However, once purchased by Gibson in 1990, a few bolt-on models were produced such as the Killer-B (with the "B" in the name standing for " bolt-on") as well as the Growler Basses. The vast majority of Tobias instruments are of neck-through construction, a style of neck-body assembly where the neck of the instrument is a single piece of wood that extends through the body and had the sides of the bass glued to it rather than being bolted on. Tobias Guitars was established in Orlando, Florida in April 1977.
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