Project description:A chemical screen was performed in search of compounds that modify plant responses to sucrose. This screen uncovered that sulfamethoxazole (SMX), a folate biosynthesis inhibitor, acted synergistically with sucrose to inhibit hypocotyl elongation, suggesting interaction between these two pathways. Transcriptome analysis was performed to identify changes in transcript abundance that may underpin crosstalk between sucrose and SMX. Three-day-old dark-grown seedlings were treated to sucrose and SMX at concentrations that induced no change in hypocotyl elongation when administered independently, yet restricted elongation when both were present in the growth media (10mM and 0.2µM, respectively). This analysis uncovered multiple core auxin signalling components that exhibit altered transcript abundance in response to co-treatment with sucrose and SMX, suggesting that auxin signalling mediates crosstalk between these two pathways. This study highlights an input through which metabolic status can shape plant growth and development through hormone signalling. 12 arrays total. Three arrays as non-treated control, three arrays from seedlings raised in presence of 0.2µM SMX, three arrays from seedlings raised in presence of 10mM sucrose, and three arrays from seeldings raised in presence of both 10mM sucrose and 0.2µM SMX. Three biological replicates were produced for each growth treatment.
Project description:Potentiated sulfonamide antibiotics such as trimethoprim/sulfamethoxazole (cotrimoxazole or TMP/SMX) remain the drugs of choice for treatment and prevention of Pneumocystis jiroveci pneumonia, toxoplasma encephalitis, and Isospora infections in HIV infection (aidsinfo.nih.gov). However, HIV-infected patients show a markedly increased risk of delayed hypersensitivity (HS) reactions to TMP/SMX (20-57% incidence) when compared to the general population (3% incidence). The typical manifestation is maculopapular rash with or without fever, and TMP/SMX is the most common cause of cutaneous drug reactions in HIV-infected patients TMP/SMX can also lead to thrombocytopenia, hepatotoxicity, and bullous skin eruptions in more severely affected patients. The risk of sulfonamide HS increases with progression to AIDS, with higher risk seen at lower CD4+ counts. This risk has been attributed, at least in part, to acquired alterations in SMX drug disposition in HIV infection. We hypothesized that HIV infection leads to impaired hepatic SMX detoxification or enhanced SMX bioactivation pathways, which may contribute to the increased incidence of sulfonamide HS. We addressed this question using liver tissue from SIVmac239-infected macaques, a well accepted model of HIV infection. The aim of this study was to evaluate differences in the hepatic expression and activity of SMX biotransformation pathways from drug naïve SIV-infected macaques compared to sex- and age-matched uninfected controls.
Project description:The global sanitary crisis derived from antibiotic multi-resistant bacteria entails the need to reduce sulfamethoxazole (SMX) concentrations in wastewater treatment plants (WWTPs). The key microorganisms and the biotransformation mechanisms leading to SMX removal remain incompletely characterized, particularly under aerobic heterotrophic conditions, which are becoming increasingly relevant in the design of novel, more energy-efficient, WWTPs. In this study, sequential batch reactors were inoculated with activated sludge, operated in heterotrophic conditions and spiked with six different initial SMX concentrations ranging between 0 and 2000 µg L-1. The goal was to determine the influence of SMX in the microbiome and its enzymatic expression through genomic, metaproteomic and transformation product analyses. The results allowed us to identify the metabolite 2,4(1H,3H)-pteridinedione-SMX (PtO-SMX), pointing to the role of the pterin-conjugation pathway in the biotransformation of SMX. Additionally, at increased SMX concentrations, through metaproteomics and 16S rRNA gene sequencing, it was determined a higher abundance of the genus Corynebacterium and a differential expression of five enzymes involved in its central metabolism, suggesting the relevant role of this bacteria to mitigate SMX risks.
Project description:A chemical screen was performed in search of compounds that modify plant responses to sucrose. This screen uncovered that sulfamethoxazole (SMX), a folate biosynthesis inhibitor, acted synergistically with sucrose to inhibit hypocotyl elongation, suggesting interaction between these two pathways. Transcriptome analysis was performed to identify changes in transcript abundance that may underpin crosstalk between sucrose and SMX. Three-day-old dark-grown seedlings were treated to sucrose and SMX at concentrations that induced no change in hypocotyl elongation when administered independently, yet restricted elongation when both were present in the growth media (10mM and 0.2µM, respectively). This analysis uncovered multiple core auxin signalling components that exhibit altered transcript abundance in response to co-treatment with sucrose and SMX, suggesting that auxin signalling mediates crosstalk between these two pathways. This study highlights an input through which metabolic status can shape plant growth and development through hormone signalling.
Project description:To explore the effect of temperature and SMX concentration on strain RNC-1, the samples at 20°C with 0 mg/L SMX was set as the control group (T20), and the other two temperature groups with 0 mg/L SMX at 10°C (T10) and 30°C (T30) were compared with it, respectively. And samples with 0 mg/L SMX were set as the control group (C0), 0.5 mg/L SMX (C0.5) and 5.0 mg/L SMX (C5) were compared with it, respectively.
Project description:Staphylococcus aureus thymidine-dependent small-colony variants (TD-SCVs) are frequently isolated from patients with chronic S. aureus infections after long-term treatment with trimethoprim-sulfamethoxazole (TMP-SMX). In TD-SCVs, mutations of thymidylate synthase (thyA, TS), essential for DNA synthesis, occur. However, it has never been shown, that TMP-SMX is responsible for the induction and selection of TD-SCVs. Short-term exposure of TMP-SMX induced the TD-SCV phenotype morphologically as shown in transmission electron-microscopy and on the transcriptional level by qRT-PCR in wild-type S. aureus, while selection of TD-SCVs with thyA mutations occurred only rarely after long-term exposure. In reversion experiments with clinical TD-SCVs, all revertants revealed compensating mutations at the initially identified mutation site. Whole DNA microarray analysis of a thyA deletion mutant (M-bM-^HM-^FthyA), which exhibited the typical TD-SCV phenotype, identified tremendous alterations compared to the wild-type. Important virulence regulators such as agr, arlRS, sarA and major virulence determinants including hla, hlb, sspA, sspB and geh were down-regulated, while genes associated with the colonization capacity like fnbA, fnbB, spa, clfB, sdrC and sdrD were up-regulated. The expression of genes involved in pyrimidine and purine metabolism as well as in nucleotide interconversion changed significantly. The M-bM-^HM-^FthyA-mutant was attenuated in virulence in both, a Caenorhabditis elegans killing model and an acute murine pneumonia model. Furthermore, competition experiments in vitro and in vivo (using a chronic pneumonia mouse model) revealed a survival and growth advantage of the M-bM-^HM-^FthyA-mutant under low thymidine conditions and TMP-SMX exposure. In conclusion, our results clearly show for the first time that TMP-SMX induces the TD-SCV phenotype after short-term exposure in S. aureus and that long-term exposure selects thyA mutations providing an advantage for TD-SCVs under specified conditions. Thus, our results help to understand the dynamic processes of induction and selection of S. aureus TD-SCVs during TMP-SMX exposure. 18 independent samples were analysed; for each isolate and time point 3 replicates were performed
Project description:Staphylococcus aureus thymidine-dependent small-colony variants (TD-SCVs) are frequently isolated from patients with chronic S. aureus infections after long-term treatment with trimethoprim-sulfamethoxazole (TMP-SMX). In TD-SCVs, mutations of thymidylate synthase (thyA, TS), essential for DNA synthesis, occur. However, it has never been shown, that TMP-SMX is responsible for the induction and selection of TD-SCVs. Short-term exposure of TMP-SMX induced the TD-SCV phenotype morphologically as shown in transmission electron-microscopy and on the transcriptional level by qRT-PCR in wild-type S. aureus, while selection of TD-SCVs with thyA mutations occurred only rarely after long-term exposure. In reversion experiments with clinical TD-SCVs, all revertants revealed compensating mutations at the initially identified mutation site. Whole DNA microarray analysis of a thyA deletion mutant (∆thyA), which exhibited the typical TD-SCV phenotype, identified tremendous alterations compared to the wild-type. Important virulence regulators such as agr, arlRS, sarA and major virulence determinants including hla, hlb, sspA, sspB and geh were down-regulated, while genes associated with the colonization capacity like fnbA, fnbB, spa, clfB, sdrC and sdrD were up-regulated. The expression of genes involved in pyrimidine and purine metabolism as well as in nucleotide interconversion changed significantly. The ∆thyA-mutant was attenuated in virulence in both, a Caenorhabditis elegans killing model and an acute murine pneumonia model. Furthermore, competition experiments in vitro and in vivo (using a chronic pneumonia mouse model) revealed a survival and growth advantage of the ∆thyA-mutant under low thymidine conditions and TMP-SMX exposure. In conclusion, our results clearly show for the first time that TMP-SMX induces the TD-SCV phenotype after short-term exposure in S. aureus and that long-term exposure selects thyA mutations providing an advantage for TD-SCVs under specified conditions. Thus, our results help to understand the dynamic processes of induction and selection of S. aureus TD-SCVs during TMP-SMX exposure.
Project description:The high frequency of prophage insertions in the mlrA gene of clinical serotype O157:H7 isolates renders such strains deficient in csgD-dependent biofilm formation but prophage induction may restore certain mlrA properties. In this study we used transcriptomics to study the effect of high and low sulfamethoxazole–trimethoprim (SMX-TM) concentrations on prophage induction, biofilm regulation, and virulence gene expression in strain PA20 under environmental conditions following five-hour and 12-hour exposures. SMX-TM at a sub-lethal concentration induced strong RecA expression resulting in concentration- and time-dependent major transcriptional shifts with emphasis on up-regulation of genes within horizontally-transferred chromosomal regions (HTR). Neither high or low levels of SMX-TM stimulated csgD expression at either time point, but both levels resulted in slight suppression. Full expression of Ler-dependent genes paralleled expression of group 1 pch homologues in the presence of high glrA. Finally, stx2 expression, which is strongly dependent on prophage induction, was enhanced at 12 hours but suppressed at five hours, in spite of early SOS initiation by the high SMX-TM concentration. Our findings indicate that, similar to host conditions, exposure to environmental conditions increased the expression of virulence genes in a clinical isolate but genes involved in the protective biofilm response were suppressed.