Doxycycline-regulated gene expression in the opportunistic fungal pathogen Aspergillus fumigatus

Vogt, Keith M.; Bhabhra, Ruchi; Rhodes, Judith C.; Askew, David

doi:10.1186/1471-2180-5-1

Cited by 133 publications

(85 citation statements)

References 31 publications

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“…To further confirm that the metH gene is indispensable for A. fumigatus, we constructed a conditional expression strain, AfS180, in which the expression of the coding sequence is driven by a doxycycline-dependent Tet-ON module (see Fig. S7 in the supplemental material) (74,75), a system that has successfully been used in A. fumigatus to prove gene essentiality (76). In the presence of doxycycline, the metH gene is properly expressed to support growth of AfS180 (Fig.…”

Section: Resultsmentioning

confidence: 99%

Exploration of Sulfur Assimilation of Aspergillus fumigatus Reveals Biosynthesis of Sulfur-Containing Amino Acids as a Virulence Determinant

et al. 2016

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e Fungal infections are of major relevance due to the increased numbers of immunocompromised patients, frequently delayed diagnosis, and limited therapeutics. To date, the growth and nutritional requirements of fungi during infection, which are relevant for invasion of the host, are poorly understood. This is particularly true for invasive pulmonary aspergillosis, as so far, sources of (macro)elements that are exploited during infection have been identified to only a limited extent. Here, we have investigated sulfur (S) utilization by the human-pathogenic mold Aspergillus fumigatus during invasive growth. Our data reveal that inorganic S compounds or taurine is unlikely to serve as an S source during invasive pulmonary aspergillosis since a sulfate transporter mutant strain and a sulfite reductase mutant strain are fully virulent. In contrast, the S-containing amino acid cysteine is limiting for fungal growth, as proven by the reduced virulence of a cysteine auxotroph. Moreover, phenotypic characterization of this strain further revealed the robustness of the subordinate glutathione redox system. Interestingly, we demonstrate that methionine synthase is essential for A. fumigatus virulence, defining the biosynthetic route of this proteinogenic amino acid as a potential antifungal target. In conclusion, we provide novel insights into the nutritional requirements of A. fumigatus during pathogenesis, a prerequisite to understanding and fighting infection.

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Section: Resultsmentioning

confidence: 99%

Exploration of Sulfur Assimilation of Aspergillus fumigatus Reveals Biosynthesis of Sulfur-Containing Amino Acids as a Virulence Determinant

et al. 2016

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“…The effect of TET or DOX on AMB susceptibility is not observed below 50 mg ml 21 (data not shown). To induce the TET promoter, some studies use 2-20 mg TET ml 21 while other studies use 100-200 mg TET ml 21 (Nakayama et al, 1998;Park & Morschhauser, 2005;Saville et al, 2003;Vogt et al, 2005). The studies using less than 50 mg ml 21 of TET or DOX may not be directly affected by alterations in AMB susceptibilities.…”

Section: Discussionmentioning

confidence: 99%

“…Despite this, a TET-inducible system has been used in several protozoan systems including Trichomonas vaginalis (Ortiz & Johnson, 2003), G. lamblia (Sun et al, 2005), Trypanosoma species (Wirtz & Clayton, 1995) and Leishmania species (Yan et al, 2001). Recently TET has been used as an inducible promoter in fungal species such as Candida albicans (Park & Morschhauser, 2005), Candida glabrata (Nakayama et al, 1998), Schizosaccharomyces pombe (Faryar & Gatz, 1992) and Aspergillus fumigatus (Vogt et al, 2005). In most of these systems, genes with an inducible TET promoter are constitutively expressed in the absence of TET, while increasing levels of TET reduce expression of the target gene.…”

Section: Introductionmentioning

confidence: 99%

Tetracycline alters drug susceptibility in Candida albicans and other pathogenic fungi

et al. 2008

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The tetracycline (TET) promoter has been used in several systems as an inducible regulator of gene expression. In control analyses, the standard Candida albicans laboratory strain SC5314 was found to have altered susceptibility to a variety of antifungal drugs in the presence of relatively high concentrations (50-200 mg ml "1 ) of TET. Altered susceptibility was most notable with exposure to amphotericin B (AMB), with a 32-fold increase in susceptibility, and terbinafine (TRB), with a 32-fold decrease in susceptibility. The TET/AMB synergy was observed in several clinical isolates of C. albicans and in the distantly related species Aspergillus fumigatus and Cryptococcus neoformans. The TET/AMB synergy is not related to efflux pump activity, as determined by FACS analyses and by analysis of a strain containing efflux pump deletions. Gene expression analyses by luciferase and by quantitative real-time reverse transcriptase PCR failed to identify significant alterations in expression of any genes associated with resistance. C. albicans grown with TET for 48 h does show a reduction in total cellular ergosterol. Analysis of growth curves suggests that the TET effect is associated with lack of a diauxic shift, which is related to a loss of mitochondrial function. MitoTracker fluorescent dye was used to demonstrate that TET has a direct effect on mitochondrial function. These results demonstrate the need for careful analysis of TET effects when using a TET-inducible promoter, especially in studies that involve antifungal drugs. This study defines some limits to the use of the TET-inducible promoter, and identifies effects on cells that are the result of TET exposure alone, not the result of expression of a targeted gene.

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“…Diarrheal disease is still a major health problem, especially in developing countries, where it is considered as one of the leading causes of morbidity and mortality especially in children. Among the bacterial pathogens, diarrheagenic Escherichia coli (DEC) is one of the important etiological agents of diarrhea (Blanco et al, 2005;Moyo et al, 2007;Asadi et al, 2010). Commensal Escherichia coli, which was discovered in 1885, is the predominant facultative anaerobe of the human gut microbiota (Lai et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

In vitro and in vivo Antibacterial Activity of Ethanolic Extract of Sweet Basil (Ocimum basilicum L.) Leaves against Escherichia coli in Experimentally Infected Rats

Ibrahim¹

2015

Adv. Anim. Vet. Sci.

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| The present study was carried out to investigate the antibacterial activity of ethanol extract of Ocimum basilicum against infectious diarrhea caused by E. coli. Two experiments were performed in this present study; the first one is in vitro antibacterial activity of Ocimum basilicum ethanolic extract. The second experiment included study in vivo antibacterial activity of the extract after inducing diarrhea with oral pathogenic E. coli in five rats groups (eight rats of each). The results of the in vitro antibacterial study showed that E. coli was more sensitive to ethanolic extract of O.B in comparison with Gentamicin and Amikacin and it was resistant to the metronidazole, but E. coli was more sensitive to Trimethoprim/Sulfamethoxazole. Two doses of O.B extract 100, 200 mg/kg. BW were used to treat this infection for fourteen days orally. The results of the in vivo study indicated that doses of 200 mg/kg BW O.B extract and 6.85 mg/kg. BW of Trimethoprim/Sulfamethoxazole were succeeded in returning the rectal E. coli count of infected rats to normal values before inducing infection in both kinds of therapy at the first week. Food intake, water intake and body weight significantly (P < 0.05) increased in comparison with others doses or groups. From the results obtained, it could be concluded that ethanolic extract of O.B leaves at dose 200 mg/kg. BW was more effective and safe in comparison with antibacterial agent and other O.B dose, this anti-diarrheal activity of O.B ethanolic extract may be due to its constituents of secondary metabolites that are responsible for the antibacterial activity with different mechanisms of action.

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Doxycycline-regulated gene expression in the opportunistic fungal pathogen Aspergillus fumigatus

Cited by 133 publications

References 31 publications

Exploration of Sulfur Assimilation of Aspergillus fumigatus Reveals Biosynthesis of Sulfur-Containing Amino Acids as a Virulence Determinant

Exploration of Sulfur Assimilation of Aspergillus fumigatus Reveals Biosynthesis of Sulfur-Containing Amino Acids as a Virulence Determinant

Tetracycline alters drug susceptibility in Candida albicans and other pathogenic fungi

In vitro and in vivo Antibacterial Activity of Ethanolic Extract of Sweet Basil (Ocimum basilicum L.) Leaves against Escherichia coli in Experimentally Infected Rats

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