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Articles one is entitled not to read!
This section [Online March 20, 2009] lists Escherichia coli adenylate cyclase-connected articles which raise suspicion concerning the review process.  The data are either poor or not interpreted properly.  In some cases interpretation of data lacks understanding of prior work.  In worst cases data are manipulated, if not falsified, as to fit an agenda.  In any case these articles would not have appeared in their present form if reviewers had been both responsible and unbiased!

February 19, 2011
Journal of Bacteriology 2011, 193(3): 649 Novel Members of the Cra Regulon Involved in Carbon Metabolism in Escherichia coli
Tomohiro Shimada, Kaneyoshi Yamamoto, and Akira Ishihama
Connection with Escherichia coli adenylate cyclase: In E. coli the fructose repressor (FruR also known as Cra) indirectly controls cAMP levels under specific conditions, see Ecach chapter III ›››

Introduction section reads: "The induction of the fructose operon takes place when the repressor Cra [FruR] is inactivated after interactions with inducers such as D-fructose-1-phosphate and D-fructose-1, 6-biphosphate. … In the presence of glucose, the intracellular concentration of the inducers increase, which interact with Cra [FruR] to prevent its binding to the target promoters".  The intracellular concentration of the inducer fructose-1-phosphate does not increase in the presence of glucose.  It 'increases' in the presence of fructose which enters the cell as fructose-1-phosphate via the phosphotransferase system (PTS).  Furthermore the synthesis of 1-phosphofructokinase is specifically induced by fructose, not glucose.  Therefore in the presence of glucose (or mannose or mannitol) the intracellular concentration of the inducer fructose-1-phosphate, and of fructose-1-6-biphosphate, cannot possibly 'increase'!  It increases in the presence of fructose.

January 31, 2011
Journal of Bacteriology 2011, 193(5): 1086 Escherichia coli exports cyclic AMP via TolC
Klaus Hantke, Karin Winkler, and Joachim E. Schultz

Results section reads: "Mutants like BTH2 cya grow as colorless colonies [on MacConkey agar plates].  Application of cAMP via filter paper discs resulted in a narrow red growth zone only around the disc which was soaked with 40 mM cAMP indicating cAMP dependent utilization of maltose" and same section further on: "Next, induction of β-galactosidase was assayed as a function of cAMP concentration.  The parent strain BTH2 cya was rather insensitive to cAMP addition.  Even at 10 mM cAMP in the medium a full response was not elicited indicating the presence of a highly effective system for cAMP export from the cells".  Both data indicates the BTH2 cya strain is unlike any other cya strains of E. coli!

December 17, 2010
FEBS Letters 2010, 584(22): 4537 A mammalian insulysin homolog is regulated by enzyme IIA^Glc of the glucose transport system in Vibrio vulnificus
You-Jin Kim, Yangkyun Ryu, Byoung-Mo Koo, Na Yeon Lee, Se-Jin Chun, Soon-Jung Park, Kyu-Ho Lee, and Yeong-Jae Seok

Glucose does not trigger dephosphorylation of Enzyme IIA^Glc in absence of the glucose permease (Enzyme IICB^Glc).  Therefore glucose does not ensure complete dephosphorylation of Enzyme IIA^Glc in the experimental conditions described by the authors in four instances.  (1) Material and Methods section reads: "To test the phosphorylation dependence of the interaction between IIA^Glc and the vIDE, vIDE [V. vulnificus insulin-degrading enzyme] was incubated with EI, HPr and His-IIA^Glc in a total volume of 500 µl of buffer A containing 2 mM DTT and 2 mM MgCl₂ in the presence of 1 mM glucose (to ensure complete dephosphorylation of His-IIA^Glc)…"  (2) Results section reads: "In one set of reactions, glucose was added, along with E. coli EI and HPr, to maintain IIA^Glc in dephosphorylated form" and (3) same section further on: "To confirm whether IIA^Glc is required for activity of vIDE, and to test whether this activation depends on the phosphorylation state of IIA^Glc, the reaction mixture containing vIDE, EI, HPr and IIA^Glc was pre-incubated with either PEP or glucose before the reaction was initiated by the addition of insulin"  (4) Legend of Figure 1(B) reads: "vIDE was incubated with EI and HPr in the presence or absence of His-IIA^Glc.  Mixtures designated Glc and PEP were supplemented with 1 mM glucose and PEP to ensure complete dephosphorylation and phosphorylation of the added IIA^Glc, respectively" (idem Figure 4).

May 22, 2009
Journal of Bacteriology 2009, 191(9): 3041 Pyruvate kinase-deficient Escherichia coli exhibits increased plasmid copy number and cyclic AMP levels
Drew S. Cunningham, Zhu Liu, Nathan Domagalski, Richard R. Koepsel, Mohammad M. Ataai, and Michael M. Domach

Discussion reads: 'Prior work also indicated that P_L8UV5 is about fourfold stronger than P_lac when both are compared for growth on glucose (21)'.  Reference (21) [J Bacteriol] does indeed describe lac up-promoter mutants including P_UV5 but none of the mutants carry the L8 mutation.  And in a repeat performance: 'As a second control, P_lac in PB25 was mutated to P_L8UV5, which is cAMP insensitive and about fourfold stronger than P_lac when these two promoters are compared for growth on either glucose-6-phosphate (37) or glucose (21)'.  In yet another example of citation violation, Discussion reads: '… glucose- 6-phosphate … is similar to glucose in repressive strength (29)'.  Not quite, see Table 1 in Reference (29) [Science].

April 17, 2009
Journal of Bacteriology 2009, 191(7): 2069 Involvement of the Cra global regulatory protein in the expression of the iscRSUA operon, revealed during studies of tricarballylate catabolism in Salmonella enterica
Jeffrey A. Lewis, Jeffrey M. Boyd, Diana M. Downs and Jorge C. Escalante-Semerena
Connection with Escherichia coli adenylate cyclase: In E. coli the fructose repressor (FruR also known as Cra) indirectly controls cAMP levels under specific conditions, see Ecach chapter III ›››

Material and Methods section reads: 'Skovran et al. previously reported that an isc mutant required nicotinic acid and thiamine for growth. The requirements for these nutrients were bypassed by using overnight cultures grown in LB, without washing the cells, to inoculate fresh medium'.  This is incorrect experimental procedure which leads to false data.

March 20, 2009
Nature Reviews Microbiology 2009, 7(3): 250 cAMP does not have an important role in carbon catabolite repression of the Escherichia coli lac operon
Atul Narang

It is unethical for Atul Narang to use the data from an article by Wanner et al. and ignore their statement that 'Much of the variation [in β-galactosidase synthesis] was eliminated by growing E. coli in the presence of cAMP, and this component we call cAMP-mediated catabolite repression' [J Bacteriol].  It is fraudulent to use the data by Wanner et al. to let the reader believe that data in Figure 1A are best fitted with a curve showing that 'to a first approximation, the β-galactosidase activity of exponentially growing cells is inversely proportional to the specific growth rate'.  Readers of the correspondence are urged to read the article by Wanner et al. and compare their data to Atul Narang's re-illustration of the same data.  Finally it is irresponsible for Atul Narang to ignore the reasoning of a previous correspondence [Medline] to discard the role of cAMP in the glucose-lactose diauxie.

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