scholarly journals γ-Resorcylate Catabolic-Pathway Genes in the Soil Actinomycete Rhodococcus jostii RHA1

2015 ◽  
Vol 81 (21) ◽  
pp. 7656-7665 ◽  
Author(s):  
Daisuke Kasai ◽  
Naoto Araki ◽  
Kota Motoi ◽  
Shota Yoshikawa ◽  
Toju Iino ◽  
...  
Keyword(s):  
Major Facilitator Superfamily ◽  
Pcr Analysis ◽  
Decarboxylase Activity ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Intergenic Regions ◽  
Major Facilitator Superfamily Transporter ◽  
Maleylacetate Reductase ◽  
Major Facilitator ◽  
Rhodococcus Jostii

ABSTRACTTheRhodococcus jostiiRHA1 gene cluster required for γ-resorcylate (GRA) catabolism was characterized. The cluster includestsdA,tsdB,tsdC,tsdD,tsdR,tsdT, andtsdX, which encode GRA decarboxylase, resorcinol 4-hydroxylase, hydroxyquinol 1,2-dioxygenase, maleylacetate reductase, an IclR-type regulator, a major facilitator superfamily transporter, and a putative hydrolase, respectively. ThetsdAgene conferred GRA decarboxylase activity onEscherichia coli. Purified TsdB oxidized NADH in the presence of resorcinol, suggesting thattsdBencodes a unique NADH-specific single-component resorcinol 4-hydroxylase. Mutations in eithertsdAortsdBresulted in growth deficiency on GRA. ThetsdCandtsdDgenes conferred hydroxyquinol 1,2-dioxygenase and maleylacetate reductase activities, respectively, onE. coli. Inactivation oftsdTsignificantly retarded the growth of RHA1 on GRA. The growth retardation was partially suppressed under acidic conditions, suggesting the involvement oftsdTin GRA uptake. Reverse transcription-PCR analysis revealed that thetsdgenes constitute three transcriptional units, thetsdBADCandtsdTXoperons andtsdR. Transcription of thetsdBADCandtsdTXoperons was induced during growth on GRA. Inactivation oftsdRderepressed transcription of thetsdBADCandtsdTXoperons in the absence of GRA, suggesting thattsdgene transcription is negatively regulated by thetsdR-encoded regulator. Binding of TsdR to thetsdR-tsdBandtsdT-tsdRintergenic regions was inhibited by the addition of GRA, indicating that GRA interacts with TsdR as an effector molecule.

scholarly journals Enhanced Efflux Pump Expression in Candida Mutants Results in Decreased Manogepix Susceptibility

2020 ◽  
Vol 64 (5) ◽  
Author(s):  
Sean D. Liston ◽  
Luke Whitesell ◽  
Mili Kapoor ◽  
Karen Joy Shaw ◽  
Leah E. Cowen
Keyword(s):  
Fungal Pathogens ◽  
Candida Parapsilosis ◽  
Efflux Pump ◽  
Major Facilitator Superfamily ◽  
Transporter Gene ◽  
Transcription Factor Gene ◽  
Content Type ◽  
Atp Binding Cassette Transporter ◽  
Major Facilitator Superfamily Transporter ◽  
Major Facilitator

ABSTRACT Manogepix is a broad-spectrum antifungal agent that inhibits glycosylphosphatidylinositol (GPI) anchor biosynthesis. Using whole-genome sequencing, we characterized two efflux-mediated mechanisms in the fungal pathogens Candida albicans and Candida parapsilosis that resulted in decreased manogepix susceptibility. In C. albicans, a gain-of-function mutation in the transcription factor gene ZCF29 activated expression of ATP-binding cassette transporter genes CDR11 and SNQ2. In C. parapsilosis, a mitochondrial deletion activated expression of the major facilitator superfamily transporter gene MDR1.

scholarly journals AbuO, a TolC-Like Outer Membrane Protein of Acinetobacter baumannii, Is Involved in Antimicrobial and Oxidative Stress Resistance

2014 ◽  
Vol 59 (2) ◽  
pp. 1236-1245 ◽  
Author(s):  
Vijaya Bharathi Srinivasan ◽  
Vasanth Vaidyanathan ◽  
Govindan Rajamohan
Keyword(s):  
Oxidative Stress ◽  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Efflux Pump ◽  
Outer Membrane Proteins ◽  
Major Facilitator Superfamily ◽  
Pcr Analysis ◽  
Content Type ◽  
Major Facilitator ◽  
And Oxidative Stress

ABSTRACTAlthoughAcinetobacter baumanniiis well accepted as a nosocomial pathogen, only a few of the outer membrane proteins (OMPs) have been functionally characterized. In this study, we demonstrate the biological functions of AbuO, a homolog of TolC fromEscherichia coli. Inactivation ofabuOled to increased sensitivity to high osmolarity and oxidative stress challenge. The ΔabuOmutant displayed increased susceptibility to antibiotics, such as amikacin, carbenicillin, ceftriaxone, meropenem, streptomycin, and tigecycline, and hospital-based disinfectants, such as benzalkonium chloride and chlorhexidine. The reverse transcription (RT)-PCR analysis indicated increased expression of efflux pumps (resistance nodulation cell division [RND] efflux pumpacrD, 8-fold; SMR-typeemrEhomolog, 12-fold; and major facilitator superfamily [MFS]-typeampGhomolog, 2.7-fold) and two-component response regulators (baeR, 4.67-fold;ompR, 10.43-fold) in the ΔabuOmutant together with downregulation ofrstA(4.22-fold) and the pilin chaperone (9-fold). The isogenic mutant displayed lower virulence in a nematode model (P< 0.01). Experimental evidence for the binding of MerR-type transcriptional regulator SoxR to radiolabeledabuOpromoter suggests regulation ofabuOby SoxR inA. baumannii.

scholarly journals The Gene Cluster forpara-Nitrophenol Catabolism Is Responsible for 2-Chloro-4-Nitrophenol Degradation in Burkholderia sp. Strain SJ98

2014 ◽  
Vol 80 (19) ◽  
pp. 6212-6222 ◽  
Author(s):  
Jun Min ◽  
Jun-Jie Zhang ◽  
Ning-Yi Zhou
Keyword(s):  
Gene Cluster ◽  
Gene Knockout ◽  
Gene Clusters ◽  
Sole Source ◽  
Pcr Analysis ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Biochemical Analyses ◽  
Nitrophenol Degradation

ABSTRACTBurkholderiasp. strain SJ98 (DSM 23195) utilizes 2-chloro-4-nitrophenol (2C4NP) orpara-nitrophenol (PNP) as a sole source of carbon and energy. Here, by genetic and biochemical analyses, a 2C4NP catabolic pathway different from those of all other 2C4NP utilizers was identified with chloro-1,4-benzoquinone (CBQ) as an intermediate. Reverse transcription-PCR analysis showed that all of thepnpgenes in thepnpABA1CDEFcluster were located in a single operon, which is significantly different from the genetic organization of all other previously reported PNP degradation gene clusters, in which the structural genes were located in three different operons. All of the Pnp proteins were purified to homogeneity as His-tagged proteins. PnpA, a PNP 4-monooxygenase, was found to be able to catalyze the monooxygenation of 2C4NP to CBQ. PnpB, a 1,4-benzoquinone reductase, has the ability to catalyze the reduction of CBQ to chlorohydroquinone. Moreover, PnpB is also able to enhance PnpA activityin vitroin the conversion of 2C4NP to CBQ. Genetic analyses indicated thatpnpAplays an essential role in the degradation of both 2C4NP and PNP by gene knockout and complementation. In addition to being responsible for the lower pathway of PNP catabolism, PnpCD, PnpE, and PnpF were also found to be likely involved in that of 2C4NP catabolism. These results indicated that the catabolism of 2C4NP and that of PNP share the same gene cluster in strain SJ98. These findings fill a gap in our understanding of the microbial degradation of 2C4NP at the molecular and biochemical levels.

scholarly journals The Major Facilitator Superfamily Transporter ZIFL2 Modulates Cesium and Potassium Homeostasis in Arabidopsis

2014 ◽  
Vol 56 (1) ◽  
pp. 148-162 ◽  
Author(s):  
Estelle Remy ◽  
Tânia R. Cabrito ◽  
Rita A. Batista ◽  
Miguel C. Teixeira ◽  
Isabel Sá-Correia ◽  
...  
Keyword(s):  
Major Facilitator Superfamily ◽  
Potassium Homeostasis ◽  
Major Facilitator Superfamily Transporter ◽  
Major Facilitator

scholarly journals N-Hydroxyarylamine O-Acetyltransferases Catalyze Acetylation of 3-Amino-4-Hydroxyphenylarsonic Acid in the 4-Hydroxy-3-Nitrobenzenearsonic Acid Transformation Pathway of Enterobacter sp. Strain CZ-1

2019 ◽  
Vol 86 (2) ◽  
Author(s):  
Ke Huang ◽  
Fan Gao ◽  
X. Chris Le ◽  
Fang-Jie Zhao
Keyword(s):  
Growth Promotion ◽  
Functional Characterization ◽  
Major Product ◽  
Site Directed Mutagenesis ◽  
Feed Additive ◽  
Pcr Analysis ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Arsanilic Acid ◽  
Relative Expression Level

ABSTRACT The organoarsenical feed additive 4-hydroxy-3-nitrobenzenearsonic acid (roxarsone [ROX]) is widely used and released into the environment. We previously showed a two-step pathway of ROX transformation by Enterobacter sp. strain CZ-1 involving the reduction of ROX to 3-amino-4-hydroxyphenylarsonic acid (3-AHPAA) and the acetylation of 3-AHPAA to N-acetyl-4-hydroxy-m-arsanilic acid (N-AHPAA) (K. Huang, H. Peng, F. Gao, Q. Liu, et al., Environ Pollut 247:482–487, 2019, https://doi.org/10.1016/j.envpol.2019.01.076). In this study, we identified two nhoA genes (nhoA1 and nhoA2), encoding N-hydroxyarylamine O-acetyltransferases, as responsible for 3-AHPAA acetylation in Enterobacter sp. strain CZ-1. The results of genetic disruption and complementation showed that both nhoA genes are involved in ROX biotransformation and that nhoA1 is the major 3-AHPAA acetyltransferase gene. Quantitative reverse transcription-PCR analysis showed that the relative expression level of nhoA1 was 3-fold higher than that of nhoA2. Each of the recombinant NhoAs was overexpressed in Escherichia coli BL21 and homogenously purified as a dimer by affinity chromatography. Both purified NhoAs catalyzed acetyl coenzyme A-dependent 3-AHPAA acetylation. The Km values of 3-AHPAA for NhoA1 and NhoA2 were 151.5 and 428.3 μM, respectively. Site-directed mutagenesis experiments indicated that two conserved arginine and cysteine residues of each NhoA were necessary for their enzyme activities. IMPORTANCE Roxarsone (ROX) is an organoarsenic feed additive that has been widely used in poultry industries for growth promotion, coccidiosis control, and meat pigmentation improvement for more than 70 years. Most ROX is excreted in the litter and dispersed into the environment, where it is transformed by microbes into different arsenic-containing compounds. A major product of ROX transformation is N-acetyl-4-hydroxy-m-arsanilic acid (N-AHPAA), which is also used as a clinical drug for treating refractory bacterial vaginosis. Here, we report the cloning and functional characterization of two genes encoding N-hydroxyarylamine O-acetyltransferases, NhoA1 and NhoA2, in Enterobacter sp. strain CZ-1, which catalyze the acetylation of 3-amino-4-hydroxyphenylarsonic acid (3-AHPAA) formed by the reduction of ROX to N-AHPAA. This study provides new insights into the function of N-hydroxyarylamine O-acetyltransferase in the transformation of an important organoarsenic compound.

scholarly journals The Sinorhizobium meliloti EmrAB Efflux System Is Regulated by Flavonoids Through a TetR-Like Regulator (EmrR)

2014 ◽  
Vol 27 (4) ◽  
pp. 379-387 ◽  
Author(s):  
Silvia Rossbach ◽  
Kati Kunze ◽  
Susann Albert ◽  
Susanne Zehner ◽  
Michael Göttfert
Keyword(s):  
Binding Sites ◽  
Sinorhizobium Meliloti ◽  
Transcriptional Regulator ◽  
Major Facilitator Superfamily ◽  
Efflux System ◽  
Obvious Effect ◽  
Potent Inducer ◽  
Nodulation Genes ◽  
Intergenic Regions ◽  
Major Facilitator

The divergently oriented Sinorhizobium meliloti emrAB (SMc03168 and SMc03167) and emrR (SMc03169) genes are predicted to encode an efflux system of the major facilitator superfamily and a TetR-like transcriptional regulator, respectively. The transcription of the emrA gene was found to be inducible by flavonoids, including luteolin and apigenin, which are known inducers of the nodulation genes in S. meliloti. Interestingly, quercetin, which does not induce nodulation genes, was also a potent inducer of emrA, indicating that NodD is not directly involved in regulation of emrA. The likely regulator of emrAB is EmrR, which binds to palindrome-like sequences in the intergenic region. Several modifications of the palindromes, including an increase of the spacing between the two half sites, prevented binding of EmrR. Binding was also impaired by the presence of luteolin. Mutations in emrA had no obvious effect on symbiosis. This was in contrast to the emrR mutant, which exhibited a symbiotic deficiency with Medicago sativa. Conserved binding sites for TetR-like regulators within the intergenic regions between the emrAB and emrR genes were identified in many symbiotic and pathogenic members of the order Rhizobiales.

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