Further investigation of the mechanism of Vitreoscilla hemoglobin (VHb) protection from oxidative stress in Escherichia coli

Biologia ◽  
2011 ◽  
Vol 66 (5) ◽  
Author(s):  
Meltem Akbas ◽  
Tugrul Doruk ◽  
Serhat Ozdemir ◽  
Benjamin Stark
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Stationary Phase ◽  
Exponential Phase ◽  
Vitreoscilla Hemoglobin ◽  
Sod Activity ◽  
E Coli ◽  
Hydrogen Peroxide Treatment

AbstractIn Escherichia coli, Vitreoscilla hemoglobin (VHb) protects against oxidative stress, perhaps, in part, by oxidizing OxyR. Here this protection, specifically VHb-associated effects on superoxide dismutase (SOD) and catalase levels, was examined. Exponential or stationary phase cultures of SOD+ or SOD− E. coli strains with or without VHb and oxyR antisense were treated with 2 mM hydrogen peroxide without sublethal peroxide induction, and compared to untreated control cultures. The hydrogen peroxide treatment was toxic to both SOD+ and SOD− cells, but much more to SOD− cells; expression of VHb in SOD+ strains enhanced this toxicity. In contrast, the presence of VHb was generally associated in the SOD+ background with a modest increase in SOD activity that was not greatly affected by oxyR antisense or peroxide treatment. In both SOD+ and SOD− backgrounds, VHb was associated with higher catalase activity both in the presence and absence of peroxide. Contrary to its stimulatory effects in stationary phase, in exponential phase oxyR antisense generally decreased VHb levels.

The Response of Antioxidant Enzyme and ATPase in Bacteria Exposed to 1,2-dichlorobenzene

2013 ◽  
Vol 807-809 ◽  
pp. 680-683 ◽  
Author(s):  
Hui Xing Liang ◽  
Ai Hui Chen ◽  
Cheng Ding ◽  
Zhao Xia Li
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Superoxide Dismutase ◽  
Dependent Manner ◽  
Bacterial Strains ◽  
Sod Activity ◽  
Concentration Dependent Manner ◽  
E Coli ◽  
Short Period ◽  
Stimulation Of

The activity response of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), ATP enzyme activities of Escherichia coli Q8, Bacillus subtilis L11, and Bacillus cereus OL-1 following exposure to 1,2-dichlorobenzene (1,2-DCB) was investigated. The bacterial strains were treated with the different concentrations of 1,2-DCB. Results obtained indicated that SOD and CAT activities in the tested bacteria increased significantly in a concentration-dependent manner after different concentrations of 1,2-DCB were applied. The activity of SOD in B. subtilis was stimulated and reached the highest level after treatment with 10 mg/L 1,2-DCB for 3 h. For B.cereus OL-1, there was another stimulation of SOD activity after 1,2-DCB application for about 5 h The stimulation by 1,2-DCB showed a relative lag for E. coli. 1,2-DCB had an evident influence on ATPase activity in the three bacteria within a relatively short period. 1,2-DCB would have caused a certain oxidative stress on the three bacteria which may not only elevate SOD and CAT activities but also generate new SOD isozymes to antagonize oxidative stress. All indirectly reflect the existence of poisonous and harmful material in the environment , and can indicate the influence of pollution sensitivily. Therefore SOD, CAT and ATP enzyme activity in microbial body can be regarded as a molecular index of polluting ,which is feasible.

Mannose-Binding Activity of Escherichia coli: a Determinant of Attachment and Ingestion of the Bacteria by Macrophages

1980 ◽  
Vol 29 (2) ◽  
pp. 417-424
Author(s):  
Zvi Bar-Shavit ◽  
Rachel Goldman ◽  
Itzhak Ofek ◽  
Nathan Sharon ◽  
David Mirelman
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Pathogenic Bacteria ◽  
Binding Activity ◽  
Exponential Phase ◽  
Restrictive Temperature ◽  
Filamentous Bacteria ◽  
Phagocytic Cells ◽  
E Coli ◽  
Mannose Binding

Recently, it was suggested that a mannose-specific lectin on the bacterial cell surface is responsible for the recognition by phagocytic cells of certain nonopsonized Escherichia coli strains. In this study we assessed the interaction of two strains of E. coli at different phases of growth with a monolayer of mouse peritoneal macrophages and developed a direct method with [ 14 C]mannan to quantitate the bacterial mannose-binding activity. Normal-sized bacteria were obtained from logarithmic and stationary phases of growth. Nonseptated filamentous cells were formed by growing the organisms in the presence of cephalexin or at a restrictive temperature. Attachment to macrophages of all bacterial forms was inhibited by methyl α- d -mannoside and mannan but not by other sugars tested. The attachment of stationary phase and filamentous bacteria to macrophages, as well as their mannose-binding activity, was similar, whereas in the exponential-phase bacteria they were markedly reduced. The results show a linear relation between the two parameters ( R = 0.98, P < 0.001). The internalization of the filamentous cells attached to macrophages during 45 min of incubation was much less efficient (20%) compared to that of exponential-phase, stationary-phase, or antibody-coated filamentous bacteria (90%). The results indicate that the mannose-binding activity of E. coli determines the recognition of the organisms by phagocytes. They further suggest that administration of β-lactam antibiotics may impair elimination of certain pathogenic bacteria by inducing the formation of filaments which are inefficiently internalized by the host's phagocytic cells.

scholarly journals Contribution of dps to Acid Stress Tolerance and Oxidative Stress Tolerance in Escherichia coli O157:H7

2000 ◽  
Vol 66 (9) ◽  
pp. 3911-3916 ◽  
Author(s):  
Sang Ho Choi ◽  
David J. Baumler ◽  
Charles W. Kaspar
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Stationary Phase ◽  
Stress Tolerance ◽  
Parent Strain ◽  
Acid Stress ◽  
Acid Tolerance ◽  
Gastric Fluid ◽  
Acid Challenge

ABSTRACT An Escherichia coli O157:H7dps::nptI mutant (FRIK 47991) was generated, and its survival was compared to that of the parent in HCl (synthetic gastric fluid, pH 1.8) and hydrogen peroxide (15 mM) challenges. The survival of the mutant in log phase (5-h culture) was significantly impaired (4-log10-CFU/ml reduction) compared to that of the parent strain (ca. 1.0-log10-CFU/ml reduction) after a standard 3-h acid challenge. Early-stationary-phase cells (12-h culture) of the mutant decreased by ca. 4 log10CFU/ml while the parent strain decreased by approximately 2 log10 CFU/ml. No significant differences in the survival of late-stationary-phase cells (24-h culture) between the parent strain and the mutant were observed, although numbers of the parent strain declined less in the initial 1 h of acid challenge. FRIK 47991 was more sensitive to hydrogen peroxide challenge than was the parent strain, although survival improved in stationary phase. Complementation of the mutant with a functional dps gene restored acid and hydrogen peroxide tolerance to levels equal to or greater than those exhibited by the parent strain. These results demonstrate that decreases in survival were from the absence of Dps or a protein regulated by Dps. The results from this study establish that Dps contributes to acid tolerance in E. coli O157:H7 and confirm the importance of Dps in oxidative stress protection.

Bacteriophage infection and multiplication occur inPseudomonas aeruginosastarved for 5 years

1997 ◽  
Vol 43 (12) ◽  
pp. 1157-1163 ◽  
Author(s):  
Holly S. Schrader ◽  
John O. Schrader ◽  
Jeremy J. Walker ◽  
Thomas A. Wolf ◽  
Kenneth W. Nickerson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Burst Size ◽  
Exponential Phase ◽  
Bacterial Mortality ◽  
E Coli ◽  
Bacteriophage Infection

Bacteriophages specific for Pseudomonas aeruginosa and Escherichia coli were examined for their ability to multiply in stationary phase hosts. Four out of five bacteriophages tested, including E. coli bacteriophage T7M, were able to multiply in stationary phase hosts. The bacteriophage ACQ had a mean burst size of approximately 1000 in exponential phase P. aeruginosa hosts and 102 in starved hosts, with corresponding latent periods that increased from 65 to 210 min. The bacteriophage UT1 had a mean burst size of approximately 211 in exponential phase P. aeruginosa hosts and 11 in starved hosts, with latent periods that increased from a mean of 90 min in exponential phase hosts to 165 min in starved hosts. Bacteriophage multiplication occurred whether or not the hosts had entered stationary phase, either because the cultures had been incubated for 24 h or were starved. Significantly, bacteriophage multiplication occurred in P. aeruginosa, which had been starved for periods of 24 h, several weeks, or 5 years. Only one P. aeruginosa virus, BLB, was found to be incapable of multiplication in stationary phase hosts. These results reveal that starvation does not offer bacterial hosts refuge from bacteriophage infection and suggest that bacteriophages will be responsible for significant bacterial mortality in most natural ecosystems.Key words: bacteriophage multiplication, stationary phase, starvation.

scholarly journals Tail-Anchored Inner Membrane Protein ElaB Increases Resistance to Stress While Reducing Persistence in Escherichia coli

2017 ◽  
Vol 199 (9) ◽  
Author(s):  
Yunxue Guo ◽  
Xiaoxiao Liu ◽  
Baiyuan Li ◽  
Jianyun Yao ◽  
Thomas K. Wood ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Stationary Phase ◽  
Transmembrane Domain ◽  
Inner Membrane ◽  
Content Type ◽  
E Coli ◽  
Inner Membrane Protein

ABSTRACT Host-associated bacteria, such as Escherichia coli, often encounter various host-related stresses, such as nutritional deprivation, oxidative stress, and temperature shifts. There is growing interest in searching for small endogenous proteins that mediate stress responses. Here, we characterized the small C-tail-anchored inner membrane protein ElaB in E. coli. ElaB belongs to a class of tail-anchored inner membrane proteins with a C-terminal transmembrane domain but lacking an N-terminal signal sequence for membrane targeting. Proteins from this family have been shown to play vital roles, such as in membrane trafficking and apoptosis, in eukaryotes; however, their role in prokaryotes is largely unexplored. Here, we found that the transcription of elaB is induced in the stationary phase in E. coli and stationary-phase sigma factor RpoS regulates elaB transcription by binding to the promoter of elaB. Moreover, ElaB protects cells against oxidative stress and heat shock stress. However, unlike membrane peptide toxins TisB and GhoT, ElaB does not lead to cell death, and the deletion of elaB greatly increases persister cell formation. Therefore, we demonstrate that disruption of C-tail-anchored inner membrane proteins can reduce stress resistance; it can also lead to deleterious effects, such as increased persistence, in E. coli. IMPORTANCE Escherichia coli synthesizes dozens of poorly understood small membrane proteins containing a predicted transmembrane domain. In this study, we characterized the function of the C-tail-anchored inner membrane protein ElaB in E. coli. ElaB increases resistance to oxidative stress and heat stress, while inactivation of ElaB leads to high persister cell formation. We also demonstrated that the transcription of elaB is under the direct regulation of stationary-phase sigma factor RpoS. Thus, our study reveals that small inner membrane proteins may have important cellular roles during the stress response.

scholarly journals Escherichia coli O157 : H7 glutamate- and arginine-dependent acid-resistance systems protect against oxidative stress during extreme acid challenge

Microbiology ◽  
2009 ◽  
Vol 155 (3) ◽  
pp. 805-812 ◽  
Author(s):  
Bradley L. Bearson ◽  
In Soo Lee ◽  
Thomas A. Casey
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Acid Stress ◽  
Acid Resistance ◽  
Dependent Manner ◽  
Bacterial Survival ◽  
E Coli ◽  
Stress Protection ◽  
Acid Challenge

Micro-organisms may simultaneously encounter multiple stresses in their environment. To investigate the protection that several known Escherichia coli O157 : H7 acid-resistance systems might provide against both oxidative and acid stress, the addition of diamide, a membrane-permeable thiol-specific oxidizing agent, or hydrogen peroxide were used concurrent with acid challenge at pH 2.5 to determine bacterial survival. The addition of either diamide or hydrogen peroxide decreased bacterial survival in a dose-dependent manner for E. coli O157 : H7 during challenge at pH 2.5 following overnight growth in LB MES pH 5.5 (acid-resistance system 1, AR1). In contrast, the presence of either glutamate or arginine during challenge provided significant protection against diamide- and hydrogen peroxide-induced oxidative stress during pH 2.5 acid challenge. Oxidative stress protection during acid challenge required gadC and adiA for the glutamate- (AR2) and arginine- (AR3) dependent acid-resistance systems, respectively. In addition, maximal protection against oxidative stress in the presence of glutamate required a low external pH (pH 2.5), since pH 5.5 did not protect. This study demonstrates that the glutamate- and arginine-dependent acid-resistance systems of E. coli O157 : H7 can simultaneously protect against oxidative stress during extreme acid challenge.

Superoxide dismutase mimetic drug tempol aggravates anti-GBM antibody-induced glomerulonephritis in mice

2010 ◽  
Vol 299 (2) ◽  
pp. F445-F452 ◽  
Author(s):  
Hua Lu ◽  
Junhui Zhen ◽  
Tianfu Wu ◽  
Ai Peng ◽  
Ting Ye ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
Immunohistochemical Staining ◽  
Treated Group ◽  
First Line ◽  
Sod Activity ◽  
Leukocyte Influx

Oxidative stress plays an important role in the pathogenesis of anti-glomerular basement membrane antibody-induced glomerulonephritis (anti-GBM-GN). Superoxide dismutase (SOD) is the first line of defense against oxidative stress by converting superoxide to hydrogen peroxide (H2O2). We investigated the effect of the SOD mimetic drug tempol on anti-GBM-GN in mice. 129/svJ mice were challenged with rabbit anti-mouse-GBM sera to induce GN and subsequently divided into tempol (200 mg·kg−1·day−1, orally) and vehicle-treated groups. Routine histology, SOD and catalase activities, malondialdehyde (MDA), H2O2, and immunohistochemical staining for neutrophils, lymphocytes, macrophages, p65-NF-κB, and osteopontin were performed. Mice with anti-GBM-GN had significantly reduced renal SOD and catalase activities and increased H2O2 and MDA levels. Unexpectedly, tempol administration exacerbated anti-GBM-GN as evidenced by intensification of proteinuria, the presence of severe crescentic GN with leukocyte influx, and accelerated mortality in the treated group. Tempol treatment raised SOD activity and H2O2 level in urine, upregulated p65-NF-κB and osteopontin in the kidney, but had no effect on renal catalase activity. Thus tempol aggravates anti-GBM-GN by increasing production of H2O2 which is a potent NF-κB activator and as such can intensify inflammation and renal injury. This supposition is supported by increases seen in p65-NF-κB, osteopontin, and leukocyte influx in the kidneys of the tempol-treated group.

Survival ofEscherichia coliexposed to visible light in seawater: analysis ofrpoS-dependent effects

1997 ◽  
Vol 43 (11) ◽  
pp. 1036-1043 ◽  
Author(s):  
M. Gourmelon ◽  
M. Pommepuy ◽  
D. Touati ◽  
M. Cormier
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Visible Light ◽  
Adaptive Response ◽  
Regulatory Gene ◽  
Exponential Phase ◽  
E Coli ◽  
Rpos Mutant ◽  
Increased Sensitivity ◽  
Key Words Escherichia Coli

We investigated the effect of visible light on Escherichia coli in seawater microcosms. Escherichia coli lost its ability to form colonies in marine environments when exposed to artificial continuous visible light. Survival of illuminated bacteria during the stationary phase was drastically reduced in the absence of the σsfactor (RpoS or KatF) that regulates numerous genes induced in this phase. In the stationary phase, double catalase mutants katE katG and mutants defective in the protein Dps (both catalase and Dps are involved in resistance to hydrogen peroxide (H2O2)), were more sensitive to light. In the exponential phase, a mutation in oxyR, the regulatory gene of the adaptive response to H2O2, increased sensitivity to light, further suggesting that deleterious effects might be associated with H2O2production. However, in the stationary phase, the katE katG dps mutant was considerably more resistant to visible light than the rpoS mutant, suggesting rpoS-dependent protection against deleterious effects other than those related to H2O2. The deleterious action of visible light was less important when the salinity decreased. In freshwater, rpoS and katE katG dps mutants did not show a drastic difference in sensitivity to light suggesting that osmolarity sensitizes E. coli to those deleterious effects of visible light that are unrelated to H2O2.Key words: Escherichia coli, stationary phase, RpoS, visible light, seawater.

Antecedent Oxygen Growth Conditions and Recovery of Heat-Stressed Escherichia coli1

1991 ◽  
Vol 54 (2) ◽  
pp. 90-93 ◽  
Author(s):  
CAROLINE E. O'NEILL ◽  
GARY K. BISSONNETTE
Keyword(s):  
Escherichia Coli ◽  
Heat Stress ◽  
Thermal Stress ◽  
Stationary Phase ◽  
Physiological State ◽  
Growth Conditions ◽  
Exponential Phase ◽  
Physiological Age ◽  
E Coli

Four strains of Escherichia coli were examined for response to heat stress (60°C) as a function of physiological age and antecedent oxygen growth conditions. Exponential phase cells were more susceptible to heat than cells grown to the stationary phase. Anaerobically grown, exponential phase cells were more susceptible to thermal stress than were cells grown to a similar physiological state but under aerobic conditions. In the case of stationary phase cells, differences in response to heat stress as related to prior oxygen growth conditions were equivocal. Repair characteristics of thermally injured cells were also examined. Cells grown anaerobically prior to heat stress required 1.5 h longer than their aerobically grown counterparts to complete repair. These findings suggest that antecedent oxygen growth conditions influence the response of E. coli to thermal stress and perhaps, more generally, that persistence of environmentally stressed enteric microorganisms must be considered in relation to prior oxygen growth conditions in vivo.

scholarly journals Identification and Characterization of a Second Superoxide Dismutase Gene (sodM) fromStaphylococcus aureus

2001 ◽  
Vol 183 (11) ◽  
pp. 3399-3407 ◽  
Author(s):  
Michelle Wright Valderas ◽  
Mark E. Hart
Keyword(s):  
Oxidative Stress ◽  
Superoxide Dismutase ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Stationary Phases ◽  
Potassium Cyanide ◽  
Exponential Phase ◽  
Sod Activity ◽  
Protein Amino Acid ◽  
Sequence Comparisons

ABSTRACT A gene encoding superoxide dismutase (SOD), sodM, fromS. aureus was cloned and characterized. The deduced amino acid sequence specifies a 187-amino-acid protein with 75% identity to the S. aureus SodA protein. Amino acid sequence comparisons with known SODs and relative insensitivity to hydrogen peroxide and potassium cyanide indicate that SodM most likely uses manganese (Mn) as a cofactor. The sodM gene expressed from a plasmid rescued an Escherichia coli double mutant (sodA sodB) under conditions that are otherwise lethal. SOD activity gels ofS. aureus RN6390 whole-cell lysates revealed three closely migrating bands of activity. The two upper bands were absent in asodM mutant, while the two lower bands were absent in asodA mutant. Thus, the middle band of activity most likely represents a SodM-SodA hybrid protein. All three bands of activity increased as highly aerated cultures entered the late exponential phase of growth, SodM more so than SodA. Viability of the sodAand sodM sodA mutants but not the sodM mutant was drastically reduced under oxidative stress conditions generated by methyl viologen (MV) added during the early exponential phase of growth. However, only the viability of the sodM sodA mutant was reduced when MV was added during the late exponential and stationary phases of growth. These data indicate that while SodA may be the major SOD activity in S. aureus throughout all stages of growth, SodM, under oxidative stress, becomes a major source of activity during the late exponential and stationary phases of growth such that viability and growth of an S. aureus sodA mutant are maintained.

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