Gas chromatographic quantification of free <scp>D</scp>‐amino acids in higher vertebrates

Pätzold, Ralf; Schieber, Andreas; Brückner, Hans

doi:10.1002/bmc.515

Cited by 53 publications

(39 citation statements)

References 22 publications

(21 reference statements)

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“…Both strains have similar doubling rates with D-serine as a sole carbon source, but interestingly, CFT073 grew much more readily and rapidly than MG1655 when utilizing D-alanine, pyruvate, or acetate as a sole carbon source. The concentration of either acetate or pyruvate in urine is unknown; however, D-alanine is present at concentrations that approach the levels of D-serine (20,37). The more-rapid growth rate of CFT073 on these carbon sources suggests, when combined with previous observations, that efficient acetogenic carbon metabolism is an adaptive response by CFT073 which permits it to readily exploit the nutritional niche of the urinary tract.…”

Section: Discussionmentioning

confidence: 92%

Uropathogenic Escherichia coli CFT073 Is Adapted to Acetatogenic Growth but Does Not Require Acetate during Murine Urinary Tract Infection

et al. 2008

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In vivo accumulation of D-serine by Escherichia coli CFT073 leads to elevated expression of PAP fimbriae and hemolysin by an unknown mechanism. Loss of D-serine catabolism by CFT073 leads to a competitive advantage during murine urinary tract infection (UTI), but loss of both D-and L-serine catabolism results in attenuation. Serine is the first amino acid to be consumed in closed tryptone broth cultures and precedes the production of acetyl phosphate, a high-energy molecule involved in intracellular signaling, and the eventual secretion of acetate. We propose that the colonization defect associated with the loss of serine catabolism is due to perturbations of acetate metabolism. CFT073 grows more rapidly on acetogenic substrates than does E. coli K-12 isolate MG1655. As shown by transcription microarray results, D-serine is catabolized into acetate via the phosphotransacetylase (pta) and acetate kinase (ackA) genes while downregulating expression of acetyl coenzyme A synthase (acs). CFT073 acs, which is unable to reclaim secreted acetate, colonized mouse bladders and kidneys in the murine model of UTI indistinguishably from the wild type. Both pta and ackA are involved in the maintenance of intracellular acetyl phosphate. CFT073 pta and ackA mutants were screened to investigate the role of acetyl phosphate in UTI pathogenesis. Both single mutants are at a competitive disadvantage relative to the wild type in the kidneys but normally colonize the bladder. CFT073 ackA pta was attenuated in both the bladder and the kidneys. Thus, we demonstrate that CFT073 is adapted to acetate metabolism as a result of requiring a proper cycling of the acetyl phosphate pathway for colonization of the upper urinary tract.Urinary tract infections (UTIs) place a significant burden on the United States healthcare system, costing upwards of $2.4 billion per year (28). The majority of women will experience a UTI in their lifetime, and every year there are approximately 6.8 million physician visits, 1.2 million emergency room visits, a quarter million hospitalizations, and thousands of deaths due to complications of UTIs, most often sepsis (10,18,28,47). Escherichia coli is the most commonly isolated causative agent of community-acquired UTIs (10).The transition from residence in the gastrointestinal tract, where uropathogenic Escherichia coli (UPEC) transiently resides, to the urinary tract represents a significant change in environment. While the gastrointestinal tract is densely populated with many different species of bacteria, the bladder is normally a sterile environment yet one that presents significant challenges to bacterial growth. In addition to the cleansing flow of urine, numerous innate and acquired immune factors challenge the growth of UPEC in the urinary tract. The host defense involves phagocytic attack, antimicrobial peptides, complement lytic and opsonizing factors, and reactive oxygen and nitrogen species. In addition, the urinary tract as reflected in urine is limited in nutrients common to the intestinal tract, esp...

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Section: Discussionmentioning

confidence: 92%

Uropathogenic Escherichia coli CFT073 Is Adapted to Acetatogenic Growth but Does Not Require Acetate during Murine Urinary Tract Infection

et al. 2008

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“…A D-serine deaminase gene can serve as a selective marker on par with antibiotic resistance genes for bacteria (16), yeast (35), or plant transformations (8) due to the toxicity of D-serine. Despite the fact that D-serine is toxic to many living organisms, D-serine is one of the most prevalent amino acids excreted in mammalian urine, at reported levels of 3 to 40 g/ml, and it can be found in mammalian blood as well (11,24). Strains of E. coli residing within the bladder show increased dsdA expression as a result of D-serine present in human urine (29).…”

Section: D-serine Is An Amino Acid Present In Mammalian Urine That Ismentioning

confidence: 99%

“…Specifically, DsdX has 33% identity with GntU, a gluconate transporter in E. coli. Due to its amino acid sequence, DsdX was classified as a member of the gluconate:H ϩ symporter family (TC 2.A.8) (31) but has been experimentally shown not to transport gluconate (24). Experimental and bioinformatic evidence strongly suggest it is an inner membrane protein (5).…”

mentioning

confidence: 99%

DsdX Is the Second d -Serine Transporter in Uropathogenic Escherichia coli Clinical Isolate CFT073

Anfora

Welch

2006

J Bacteriol

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D-Serine is an amino acid present in mammalian urine that is inhibitory toEscherichia coli is a normal resident of the vertebrate large intestine, and certain pathogenic strains are capable of infecting sites outside of the intestine. The sequencing of multiple E. coli genomes has allowed for a better insight into what genes may permit success in niches outside the intestine. Comparison of an E. coli K-12 isolate (MG1655) to an O157:H7 enterohemorrhagic E. coli isolate (EDL933) and a uropathogenic E. coli (UPEC) isolate (CFT073) showed numerous genetic differences between the strains. Less than 50% of the apparent genes were common to all three strains; these common genes represent what can be thought of as the core chromosome of E. coli. The variable regions specific to each isolate include genes potentially important to disease or growth in different environments (38). One such variable site is a genetic island starting 3Ј to the argW tRNA gene and ending with the dsdCXA locus. The dsdCXA locus is intact in MG1655 and CFT073 but is truncated in EDL933 (28). In fact, the dsdCXA locus is intact in most extraintestinal pathogenic E. coli (ExPEC) strains but is truncated in the vast majority of diarrheagenic E. coli strains (R. L. Moritz and R. A. Welch, submitted for publication). This region of the E. coli chromosome frequently replaces dsdC and dsdX with csrRAKB genes responsible for sucrose catabolism (12,28).The E. coli dsdCXA locus permits growth on D-serine as a sole carbon and nitrogen source. The E. coli K-12 dsdCXA locus was extensively studied by McFall and coworkers (23). The DNA sequence of the locus was originally described by this group, but apparent sequence assembly problems and the inability at the time to create targeted, site-specific mutations prevented proper identification and functional analysis of dsdX. The dsdC gene encodes a Lys-R-type transcriptional regulator that induces transcription of dsdX and dsdA in the presence of D-serine and inhibits its own transcription in the absence of D-serine (23). DsdX has been hypothesized to act as a D-serine transporter (23). The dsdA gene encodes a pyridoxal phosphate-dependent D-serine deaminase (DsdA) that degrades D-serine to ammonia and pyruvate (18). D-Serine catabolism is biologically important because D-serine is available in some environments as a readily utilizable nutrient source, but it can also have also inhibitory effects on growth. D-Serine is bacteriostatic to cells lacking DsdA grown in minimal medium (16). D-Serine toxicity on minimal medium can be reversed with expression of functional DsdA or by the addition of pantothenate or ␤-alanine to the medium; this suggests that the inhibitory effect of D-serine is associated with pantothenate biosynthesis due to the structural similarity between D-serine and ␤-alanine (2, 4, 7, 15). A D-serine deaminase gene can serve as a selective marker on par with antibiotic resistance genes for bacteria (16), yeast (35), or plant transformations (8) due to the toxicity of D-serine. Despite the fact t...

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“…Recently, d-amino acids (DAAs) have been researched in various scientific fields [1][2][3]. For example, it has been known that d-serine has a function to adjust glutamatergic neurotransmission in brain [4,5].…”

Section: Introductionmentioning

confidence: 99%

Development of a d-amino acids electrochemical sensor based on immobilization of thermostable d-Proline dehydrogenase within agar gel membrane

Tani

Tanaka

Yabutani

et al. 2008

Analytica Chimica Acta

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Gas chromatographic quantification of free D‐amino acids in higher vertebrates

Cited by 53 publications

References 22 publications

Uropathogenic Escherichia coli CFT073 Is Adapted to Acetatogenic Growth but Does Not Require Acetate during Murine Urinary Tract Infection

Uropathogenic Escherichia coli CFT073 Is Adapted to Acetatogenic Growth but Does Not Require Acetate during Murine Urinary Tract Infection

DsdX Is the Second d -Serine Transporter in Uropathogenic Escherichia coli Clinical Isolate CFT073

Development of a d-amino acids electrochemical sensor based on immobilization of thermostable d-Proline dehydrogenase within agar gel membrane

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