Determination of bacterial cell volume with the Coulter Counter

Kubitschek, H.E.; Friske, J.A.

doi:10.1128/jb.168.3.1466-1467.1986

Cited by 125 publications

(109 citation statements)

References 4 publications

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“…The CoA and total ACP pools were estimated to be 20 -90 and 4 -10 pmol/10 8 cells, respectively (23,24,26,(43)(44)(45). Thus, the CoA and total ACP concentrations in the cell are approximately 400 -1800 and 90 -200 M, respectively, if the cell volume is assumed to be 0.5 m 3 (46). Interestingly, the relative affinities of both AcpS enzymes determined for their substrates apparently correlate with the estimated in vivo concentrations of CoA and ACP.…”

Section: Discussionmentioning

confidence: 85%

Biochemical and Molecular Analyses of the Streptococcus pneumoniae Acyl Carrier Protein Synthase, an Enzyme Essential for Fatty Acid Biosynthesis

McAllister

Peery

Meier

et al. 2000

Journal of Biological Chemistry

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Acyl carrier protein synthase (AcpS) is an essential enzyme in the biosynthesis of fatty acids in all bacteria. AcpS catalyzes the transfer of 4-phosphopantetheine from coenzyme A (CoA) to apo-ACP, thus converting apo-ACP to holo-ACP that serves as an acyl carrier for the biosynthesis of fatty acids and lipids. To further understand the physiological role of AcpS, we identified, cloned, and expressed the acpS and acpP genes of Streptococcus pneumoniae and purified both products to homogeneity. Both acpS and acpP form operons with the genes whose functions are required for other cellular metabolism. The acpS gene complements an Escherichia coli mutant defective in the production of AcpS and appears to be essential for the growth of S. pneumoniae. Gel filtration and cross-linking analyses establish that purified AcpS exists as a homotrimer. AcpS activity was significantly stimulated by apo-ACP at concentrations over 10 M and slightly inhibited at concentrations of 5-10 M. Double reciprocal analysis of initial velocities of AcpS at various concentrations of CoA or apo-ACP indicated a random or compulsory ordered bi bi type of reaction mechanism. Further analysis of the inhibition kinetics of the product (3,5-ADP) suggested that it is competitive with respect to CoA but mixed (competitive and noncompetitive) with respect to apo-ACP. Finally, apo-ACP bound tightly to AcpS in the absence of CoA, but CoA failed to do so in the absence of apo-ACP. Together, these results suggest that AcpS may be allosterically regulated by apo-ACP and probably proceeds by an ordered reaction mechanism with the first formation of the AcpS-apo-ACP complex and the subsequent transfer of 4-phosphopantetheine to the apo-ACP of the complex.

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Section: Discussionmentioning

confidence: 85%

Biochemical and Molecular Analyses of the Streptococcus pneumoniae Acyl Carrier Protein Synthase, an Enzyme Essential for Fatty Acid Biosynthesis

McAllister

Peery

Meier

et al. 2000

Journal of Biological Chemistry

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“…Nucleotide concentrations calculated by regression analysis of known standards were normalized for bacterial density as measured spectrophotometrically at A 600 nm . Intracellular nucleotide concentrations were calculated taking into account a bacterial cell volume of 10 Ϫ15 liters (35). Glutathione Quantification-Total (GSH-GSSG) or oxidized glutathione (GSSG) was extracted and measured using a glutathione recycling method described by Baker et al (36).…”

Section: Methodsmentioning

confidence: 99%

Control of Redox Balance by the Stringent Response Regulatory Protein Promotes Antioxidant Defenses of Salmonella

Henard

Bourret

Song

et al. 2010

Journal of Biological Chemistry

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“…Assuming a 1 µm 3 mean cell volume [25] and linear volume increase in time [26], the volume after doubling is approximately 0.7 µm 3 , leading to a concentration of 34,286 nM.…”

Section: Parameter Valuesmentioning

confidence: 99%

Determinants of bistability in induction of the Escherichia coli lac operon

et al. 2008

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We have developed a mathematical model of regulation of expression of the Escherichia coli lac operon, and have investigated bistability in its steady-state induction behavior in the absence of external glucose.Numerical analysis of equations describing regulation by artificial inducers revealed two natural bistability parameters that can be used to control the range of inducer concentrations over which the model exhibits bistability. By tuning these bistability parameters, we found a family of biophysically reasonable systems that are consistent with an experimentally determined bistable region for induction by thio-methylgalactoside (Ozbudak et al. Nature 427:737, 2004). The model predicts that bistability can be abolished when passive transport or permease export becomes sufficiently large; the former case is especially relevant to induction by isopropyl-β, D-thiogalactopyranoside. To model regulation by lactose, we developed similar equations in which allolactose, a metabolic intermediate in lactose metabolism and a natural inducer of lac, is the inducer. For biophysically reasonable parameter values, these equations yield no bistability in response to induction by lactose; however, systems with an unphysically small permease-dependent export effect can exhibit small amounts of bistability for limited ranges of parameter values. These results cast doubt on the relevance of bistability in the lac operon within the natural context of E. coli, and help shed light on the controversy among existing theoretical studies that address this issue. The results also suggest an experimental approach to address the relevance of bistability in the lac operon within the natural context of E. coli.

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Determination of bacterial cell volume with the Coulter Counter

Cited by 125 publications

References 4 publications

Biochemical and Molecular Analyses of the Streptococcus pneumoniae Acyl Carrier Protein Synthase, an Enzyme Essential for Fatty Acid Biosynthesis

Biochemical and Molecular Analyses of the Streptococcus pneumoniae Acyl Carrier Protein Synthase, an Enzyme Essential for Fatty Acid Biosynthesis

Control of Redox Balance by the Stringent Response Regulatory Protein Promotes Antioxidant Defenses of Salmonella

Determinants of bistability in induction of the Escherichia coli lac operon

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