4 results on '"HAIYAN HAN"'
Search Results
2. PhoU2 but Not PhoU1 as an Important Regulator of Biofilm Formation and Tolerance to Multiple Stresses by Participating in Various Fundamental Metabolic Processes in Staphylococcus epidermidis
- Author
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ZhiHui Lv, Yongpeng Shang, Tao Xu, Yang Wu, Xiaofei Wang, Di Qu, Haiyan Han, Ying Zhang, and Zhiwei Lin
- Subjects
0301 basic medicine ,Citric Acid Cycle ,030106 microbiology ,Mutant ,Biology ,Pentose phosphate pathway ,Microbiology ,biofilm ,Phosphates ,Pentose Phosphate Pathway ,03 medical and health sciences ,Bacterial Proteins ,Stress, Physiological ,Drug tolerance ,Staphylococcus epidermidis ,Operon ,Glycolysis ,Molecular Biology ,tolerance ,ATP synthase ,Gene Expression Profiling ,Biofilm ,Membrane Transport Proteins ,Gene Expression Regulation, Bacterial ,Hydrogen Peroxide ,biology.organism_classification ,Anti-Bacterial Agents ,ATP Synthetase Complexes ,Citric acid cycle ,Biochemistry ,Biofilms ,Mutation ,biology.protein ,NADP ,Research Article - Abstract
PhoU, a conserved protein that has been proposed to coordinate phosphate import, is a negative regulator of drug tolerance in most bacteria. In Staphylococcus epidermidis , the role of PhoU in biofilm formation and drug tolerance has not yet been investigated. Two PhoU homologs in the genome of S. epidermidis have been identified by the presence of the conserved motif E(D)XXXD of PhoU. We separately constructed Δ phoU1 and Δ phoU2 mutants of S. epidermidis strain 1457. The Δ phoU2 mutant displayed growth retardation, a weakened biofilm formation capacity, a higher sensitivity to H 2 O 2 , and reduced tolerance to multiple antibiotics. However, deletion of phoU1 had no effect on those. We compared the transcriptome profiles of the Δ phoU2 and Δ phoU1 mutants with that of the parent strain. In the Δ phoU2 mutant, expression of genes related to inorganic phosphate uptake was significantly upregulated ( pst operon) and the levels of intracellular inorganic polyphosphate (polyP) were increased. In the Δ phoU2 mutant, expression of enzymes in the pentose phosphate pathway (PPP) was downregulated and less NADP (NADPH) was detected, consistent with the high sensitivity to H 2 O 2 and the growth retardation of the Δ phoU2 mutant. The upregulated expression of ATP synthase was consistent with the high intracellular ATP content in the Δ phoU2 mutant, which may have been related to the lower drug tolerance of the Δ phoU2 mutant. This study demonstrates that PhoU2, but not PhoU1, in S. epidermidis regulates bacterial growth, biofilm formation, oxidative stress, and drug tolerance in association with alterations to inorganic phosphate metabolism, the pentose phosphate pathway, galactose metabolism, the tricarboxylic acid (TCA) or citric cycle, glycolysis and gluconeogenesis, and respiratory reactions. IMPORTANCE PhoU is widely conserved throughout the bacterial kingdom and plays an important role in response to stress and metabolic maintenance. In our study, two PhoU homologs were found in S. epidermidis . The function of phoU2 , but not phoU1 , in S. epidermidis is related to growth, drug tolerance, the oxidative stress response, polyP levels, and ATP accumulation. In addition, phoU2 regulates biofilm formation. Hence, phoU2 is a regulator of both drug tolerance and biofilm formation, which are two bacterial properties that present major challenges to the clinical treatment of infections. Analysis of differential gene expression revealed that phoU2 is involved in fundamental metabolic processes, such as the PPP pathway. These findings indicate that phoU2 is a crucial regulator in S. epidermidis .
- Published
- 2017
3. PhoU2 but Not PhoU1 as an Important Regulator of Biofilm Formation and Tolerance to Multiple Stresses by Participating in Various Fundamental Metabolic Processes in Staphylococcus epidermidis.
- Author
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Xiaofei Wang, Haiyan Han, Zhihui Lv, Zhiwei Lin, Yongpeng Shang, Tao Xu, Yang Wu, Ying Zhang, and Di Qu
- Abstract
PhoU, a conserved protein that has been proposed to coordinate phosphate import, is a negative regulator of drug tolerance in most bacteria. In Staphylococcus epidermidis, the role of PhoU in biofilm formation and drug tolerance has not yet been investigated. Two PhoU homologs in the genome of S. epidermidis have been identified by the presence of the conserved motif E(D)XXXD of PhoU. We separately constructed ΔphoU1 and ΔphoU2 mutants of S. epidermidis strain 1457. The ΔphoU2 mutant displayed growth retardation, a weakened biofilm formation capacity, a higher sensitivity to H2O2, and reduced tolerance to multiple antibiotics. However, deletion of phoU1 had no effect on those. We compared the transcriptome profiles of the ΔphoU2 and ΔphoU1 mutants with that of the parent strain. In the ΔphoU2 mutant, expression of genes related to inorganic phosphate uptake was significantly upregulated (pst operon) and the levels of intracellular inorganic polyphosphate (polyP) were increased. In the ΔphoU2 mutant, expression of enzymes in the pentose phosphate pathway (PPP) was downregulated and less NADP (NADPH) was detected, consistent with the high sensitivity to H2O2 and the growth retardation of the ΔphoU2 mutant. The upregulated expression of ATP synthase was consistent with the high intracellular ATP content in the ΔphoU2 mutant, which may have been related to the lower drug tolerance of the ΔphoU2 mutant. This study demonstrates that PhoU2, but not PhoU1, in S. epidermidis regulates bacterial growth, biofilm formation, oxidative stress, and drug tolerance in association with alterations to inorganic phosphate metabolism, the pentose phosphate pathway, galactose metabolism, the tricarboxylic acid (TCA) or citric cycle, glycolysis and gluconeogenesis, and respiratory reactions. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
4. Staphylococcus epidermidis SrrAB Regulates Bacterial Growth and Biofilm Formation Differently under Oxic and Microaerobic Conditions.
- Author
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Youcong Wu, Yang Wu, Tao Zhu, Haiyan Han, Huayong Liu, Tao Xu, Patrice Francois, Li Bai, Götz, Friedrich, Di Qu, and Fischer, Adrien
- Subjects
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STAPHYLOCOCCUS epidermidis , *BACTERIAL proteins , *GENETIC mutation , *BACTERIAL growth prevention , *BIOFILMS , *GENETIC transcription in bacteria , *CYTOCHROMES , *OXIDASES - Abstract
SrrAB expression in Staphylococcus epidermidis strain 1457 (SE1457) was upregulated during a shift from oxic to microaerobic conditions. An srrA deletion (ΔsrrA) mutant was constructed for studying the regulatory function of SrrAB. The deletion resulted in retarded growth and abolished biofilm formation both in vitro and in vivo and under both oxic and microaerobic conditions. Associated with the reduced biofilm formation, the ΔsrrA mutant produced much less polysaccharide intercellular adhesion (PIA) and showed decreased initial adherence capacity. Microarray analysis showed that the srrA mutation affected transcription of 230 genes under microaerobic conditions, and 51 genes under oxic conditions. Quantitative real-time PCR confirmed this observation and showed downregulation of genes involved in maintaining the electron transport chain by supporting cytochrome and quinol-oxidase assembly (e.g., qoxB and ctaA) and in anaerobic metabolism (e.g., pflBA and nrdD). In the ΔsrrA mutant, the expression of the biofilm formation-related gene icaR was upregulated under oxic conditions and downregulated under microaerobic conditions, whereas icaA was downregulated under both conditions. An electrophoretic mobility shift assay further revealed that phosphorylated SrrA bound to the promoter regions of icaR, icaA, qoxB, and pflBA, as well as its own promoter region. These findings demonstrate that in S. epidermidis SrrAB is an autoregulator and regulates biofilm formation in an ica-dependent manner. Under oxic conditions, SrrAB modulates electron transport chain activity by positively regulating qoxBACD transcription. Under microaerobic conditions, it regulates fermentation processes and DNA synthesis by modulating the expression of both the pfl operon and nrdDG. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
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