Presence of the bacterial hemoglobin gene improves α-amylase production of a recombinantEscherichia coli strain

Khosravi, Mahvash; Webster, D. R.; Stark, Benjamin C.

doi:10.1016/0147-619x(90)90002-t

Cited by 81 publications

(73 citation statements)

References 12 publications

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“…1, 2, 3 and 4). The changes in growth patterns and lead utilization by transformed cells could be due to direct effects of bacterial hemoglobin (VHb) or more subtlety and indirect effects of (VHb) on cell metabolism (De Mondena et al, 1993;Kallio et al, 1994;Khosla and Bailey, 1988;Khosravi et al, 1990).…”

Section: Resultsmentioning

confidence: 99%

“…It has been demonstrated by genetic engineering, that intracellular expression of a bacterial hemoglobin from Vitreoscilla (VHb) in different hosts elicits in vivo, effects of hypooxic conditions for strictly aerobic microorganisms. Also increased formation of usefully products and consequently improved cell growth (De Mondena et al, 1993;Khosravi et al, 1990;Khosla and Bailey, 1988). The aims of the present study were (1): To determine changes in growth curves of E. coli strain "DH5 and transformed E. coli strain "DH5 with the Vitreoscilla hemoglobin gene (vgb) on pb-containing media.…”

Section: Introductionmentioning

confidence: 99%

“…As mentioned above, the genetically engineered bacteria have been produced to enhance their ability to grow, survive and thrive under extreme conditions. Therefore they can metabolize target chemicals compounds under these condition (Khosravi et al, 1990;Mains and Kappas, 1977;De Mondena et al, 1993;Kallio et al, 1994;Khosla and Bailey, 1988;Moat and Foster, 1988;Dressler et al, 1991). (2): To determine Pb uptake, biosorption and adsorption in both strains.…”

Section: Introductionmentioning

confidence: 99%

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Bacterial Hemoglobin gene (vgb) Transformed into Escherichia coli enhances Lead-Uptake and Minimizes it’s Adsorption

Khliefat¹,

Homady²

2000

Pakistan J. of Biological Sciences

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Abstract:In Escherichia coli transformed with bacterial hemoglobin gene (vgb) has been shown to increase lead (Pb) uptake, growth yield of the cells grown in LB containing different concentration of Pb. The maximum Pb biosorption of vgb-containing and parental cells were determined to be 51 and 30.8 ppm Pb gG 1 biomass respectively. Using growth curves by liquid and solid media the inhibitory effect of Pb on parental strain was detected at lowest concentration (10 ppm). However, in vgb-containing cells, Pb was lethal at 100 ppm. The optimum aeration that required for the cellscontaining hemoglobin gene (vgb) was lower than that of the same strain without vgb on a growth yield, Pb uptake and Pb adsorption basis. The quantity of the Pb uptake inside the cells appears to be independent on the concentration of bacterial cells. On the other hand, in E. coli strain VHb the ability of the cells to uptake Pb was primarily a function of the hemoglobin content. The higher the Pb uptake the lower the Pb adsorption. The opposite results was achieved for parental cells in which the higher Pb adsorption the lower Pb uptake.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Bacterial Hemoglobin gene (vgb) Transformed into Escherichia coli enhances Lead-Uptake and Minimizes it’s Adsorption

Khliefat¹,

Homady²

2000

Pakistan J. of Biological Sciences

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“…While this pattern of regulation and the oxygen-binding properties of the molecule portend physiological function, there is no data to suggest a metabolic role for VHb in Vitreoscillu. However, cloning and expression of the gene (vhb) for VHb has enabled demonstration of a significant metabolic effect of VHb in several heterologous organisms [3,4,[8][9][10].…”

Section: Intracellular Expression Ofmentioning

confidence: 99%

Intracellular expression of Vitreoscilla hemoglobin alters Escherichia coli energy metabolism under oxygen‐limited conditions

Kallio

Kim

Tsai

et al. 1994

European Journal of Biochemistry

148

110

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An earlier stoichiometric analysis of oxygen‐limited metabolism of Escherichia coli expressing cloned Vitreoscilla hemoglobin (VHb) suggested improved efficiency of ATP production relative to wild‐type controls [Khosla, C., Curtis, J. E., DeModena, J., Rinas, J. & Bailey, J. E. (1990) Bio‐Technol. 8, 849–853]. This hypothesis has been further examined by determining several energetic parameters of different VHb‐expressing E. coli (VHb+) strains relative to controls not expressing VHb (VHb–). The H+/O ratio, the transmembrane ΔpH, and the ATP content of VHb+ constructs are 1.5, 1.6 and 2 times, respectively, corresponding values in VHb– controls. VHb was expressed using a low‐copy‐number vector in E. coli mutant strains lacking cytochrome o, cytochrome d, or both terminal oxidases; significant growth enhancement due to VHb expression was observed only in the strain having functional cytochrome o and lacking cytochrome d. All of these data obtained using different E. coli strains are consistent with a model of VHb action that hypothesizes enhancement by VHb of activity of the lower oxygen‐affinity, higher proton‐pumping‐efficiency cytochrome o terminal oxidase under oxygen‐limited growth conditions.

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“…VHb has been reported to increase the activity of terminal oxidases by increasing the local supply of oxygen (2,3) and to support the aerobic growth of strains deficient in terminal oxidases (4). Expression of VHb in heterologous bacteria often enhances growth, increases yields of recombinant proteins, and enhances production of antibiotics, especially under oxygen-limiting conditions (5)(6)(7)(8). In Rhizobium etli, for example, the expression of vgb in free living cells grown under most oxygen-limiting conditions resulted in an increase in respiratory activity, increased chemical energy content, and expression of the nitrogen-fixation gene nifHc.…”

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confidence: 99%

Vitreoscilla Hemoglobin Binds to Subunit I of Cytochrome bo Ubiquinol Oxidases

Park

Kim

Howard

et al. 2002

Journal of Biological Chemistry

Self Cite

107

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The bacterium, Vitreoscilla, can induce the synthesis of a homodimeric hemoglobin under hypoxic conditions. Expression of VHb in heterologous bacteria often enhances growth and increases yields of recombinant proteins and production of antibiotics, especially under oxygen-limiting conditions. There is evidence that VHb interacts with bacterial respiratory membranes and cytochrome bo proteoliposomes. We have examined whether there are binding sites for VHb on the cytochrome, using the yeast two-hybrid system with VHb as the bait and testing every Vitreoscilla cytochrome bo subunit as well as the soluble domains of subunits I and II. A significant interaction was observed only between VHb and intact subunit I. We further examined whether there are binding sites for VHb on cytochrome bo from Escherichia coli and Pseudomonas aeruginosa, two organisms in which stimulatory effects of VHb have been observed. Again, in both cases a significant interaction was observed only between VHb and subunit I. Because subunit I contains the binuclear center where oxygen is reduced to water, these data support the function proposed for VHb of providing oxygen directly to the terminal oxidase; it may also explain its positive effects in Vitreoscilla as well as in heterologous organisms.

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Presence of the bacterial hemoglobin gene improves α-amylase production of a recombinantEscherichia coli strain

Cited by 81 publications

References 12 publications

Bacterial Hemoglobin gene (vgb) Transformed into Escherichia coli enhances Lead-Uptake and Minimizes it’s Adsorption

Bacterial Hemoglobin gene (vgb) Transformed into Escherichia coli enhances Lead-Uptake and Minimizes it’s Adsorption

Intracellular expression of Vitreoscilla hemoglobin alters Escherichia coli energy metabolism under oxygen‐limited conditions

Vitreoscilla Hemoglobin Binds to Subunit I of Cytochrome bo Ubiquinol Oxidases

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