Physiological Function and Metabolism of Free D-Alanine in Aquatic Animals

Abe, Hiroki; Yoshikawa, Norishige; Sarower, Mohammed Golam; Okada, Shigeru

doi:10.1248/bpb.28.1571

Cited by 87 publications

(46 citation statements)

References 47 publications

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“…Interestingly, D-amino acids and D-Ala in particular have been found in tissues of marine animals (48,49), leading us to speculate that at least the alr mutant might colonize squid. However, both RM1 and AN3 were severely attenuated in colonization (Fig.…”

Section: Resultsmentioning

confidence: 99%

An Expanded Transposon Mutant Library Reveals that Vibrio fischeri δ-Aminolevulinate Auxotrophs Can Colonize Euprymna scolopes

Lyell

Septer

Dunn

et al. 2017

Appl Environ Microbiol

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Libraries of defined mutants are valuable research tools but necessarily lack gene knockouts that are lethal under the conditions used in library construction. In this study, we augmented a Vibrio fischeri mutant library generated on a rich medium (LBS, which contains [per liter] 10 g of tryptone, 5 g of yeast extract, 20 g of NaCl, and 50 mM Tris [pH 7.5]) by selecting transposon insertion mutants on supplemented LBS and screening for those unable to grow on LBS. We isolated strains with insertions in alr, glr (murI), glmS, several heme biosynthesis genes, and ftsA, as well as a mutant disrupted 14 bp upstream of ftsQ. Mutants with insertions in ftsA or upstream of ftsQ were recovered by addition of Mg 2ϩ to LBS, but their cell morphology and motility were affected. The ftsA mutant was more strongly affected and formed cells or chains of cells that appeared to wind back on themselves helically. Growth of mutants with insertions in glmS, alr, or glr was recovered with N-acetylglucosamine (NAG), D-alanine, or D-glutamate, respectively. We hypothesized that NAG, D-alanine, or D-glutamate might be available to V. fischeri in the Euprymna scolopes light organ; however, none of these mutants colonized the host effectively. In contrast, hemA and hemL mutants, which are auxotrophic for ␦-aminolevulinate (ALA), colonized at wild-type levels, although mutants later in the heme biosynthetic pathway were severely impaired or unable to colonize. Our findings parallel observations that legume hosts provide Bradyrhizobium symbionts with ALA, but they contrast with virulence phenotypes of hemA mutants in some pathogens. The results further inform our understanding of the symbiotic light organ environment.IMPORTANCE By supplementing a rich yeast-based medium, we were able to recover V. fischeri mutants with insertions in conditionally essential genes, and further characterization of these mutants provided new insights into this bacterium's symbiotic environment. Most notably, we show evidence that the squid host can provide V. fischeri with enough ALA to support its growth in the light organ, paralleling the finding that legumes provide Bradyrhizobium ALA in symbiotic nodules. Taken together, our results show how a simple method of augmenting already rich media can expand the reach and utility of defined mutant libraries.KEYWORDS Photobacterium, Aliivibrio, symbiosis, aminolevulinic acid, hemin, photobacteria D efined knockout mutant libraries are useful resources that have been generated to promote research in several bacterial experimental models and pathogens (1-10). In such studies, researchers have often listed essential genes, the knockouts of which were apparently lethal under the conditions of library construction and therefore not represented by mutants in the library. In order to recover insertion mutants collectively

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Section: Resultsmentioning

confidence: 99%

An Expanded Transposon Mutant Library Reveals that Vibrio fischeri δ-Aminolevulinate Auxotrophs Can Colonize Euprymna scolopes

Lyell

Septer

Dunn

et al. 2017

Appl Environ Microbiol

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“…Viant et al (2003) have reported that some marine molluscs used high intracellular concentrations of free amino acids to balance their intracellular osmolarity with the environment, and these pools of oxidizable amino acids were also used extensively in cellular energy metabolism. Alanine is another important organic osmolyte like betaine, taurine, homarine and glycine in many invertebrates (Abe et al, 2005). It has also been reported that alanine constitutes the major portion of end-product of glucose breakdown anaerobically, together with the metabolite of succinate in invertebrate (Carlsson and Gade, 1986;Stokes and Awapara, 1968).…”

Section: Discussionmentioning

confidence: 99%

Benzo(a)pyrene-induced metabolic responses in Manila clam Ruditapes philippinarum by proton nuclear magnetic resonance (1H NMR) based metabolomics

Zhang

Liu

You

et al. 2011

Environmental Toxicology and Pharmacology

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“…Hereby, the increase in arginine and ATP was the metabolic biomarkers of energetic disturbance induced by the metals as well. Alanine is another important organic osmolyte like betaine, taurine, homarine and glycine in many invertebrates (Abe et al 2005). It has also been reported that alanine constitutes the major portion of end-product of glucose breakdown anaerobically, together with the metabolite of succinate in invertebrate (Carlsson and Gade 1986;Stokes and Awapara 1968).…”

Section: Discussionmentioning

confidence: 99%

Differential toxicological effects induced by mercury in gills from three pedigrees of Manila clam Ruditapes philippinarum by NMR-based metabolomics

et al. 2010

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Mercury is a hazardous pollutant in the Bohai marine environments due to its high toxicity to the marine organisms and subsequent ecological risk. Manila clam Ruditapes philippinarum is one of important sentinel organisms in 'Mussel Watch Program' launched in China and therefore used as a bioindicator in marine and coastal ecotoxicology. There are dominantly distributed three pedigrees of clam (White, Liangdao Red and Zebra) in Yantai population endowed with different tolerances to environmental stressors. In this study, gill tissues were collected from both untreated and mercury exposed White, Liangdao Red and Zebra clams, and the extracts were analyzed by NMR-based metabolomics to compare the original metabolomes and the toxicological effects induced by mercury exposure in three pedigrees. The major abundant metabolites in White clam sample were branchedchain amino acids, lactate, alanine, arginine, acetoacetate, glutamate, succinate, citrate, malonate and taurine, while the metabolite profile of Liangdao Red clam sample comprises relative high levels of alanine, arginine, glutamate, succinate and glycogen. For Zebra clam sample, the metabolite profile exhibited relatively high amount of aspartate, acetylcholine and homarine. After 48 h exposure of 20 lg l -1 Hg 2? , the metabolic profiles from all the three pedigrees of clams commonly showed significant increases in alanine, arginine, glutamate, aspartate, a-ketoglutarate, glycine and ATP/ADP, and decreases in citrate, taurine and homarine. The unique metabolic differences between the metabolomes of gill tissues from Hg 2? -exposed White, Liangdao Red and Zebra clams were found, including elevated acetylcholine and branched-chain amino acids in White clams, and the declined succinate in both White and Liangdao Red samples as well as the declined betaine in Zebra and White clams. Overall, our findings showed the differential toxicological responses to mercury exposure and that White clams could be a preferable bioindicator for the metal pollution monitoring based on the metabolic changes from gill compared with other two (Liangdao Red and Zebra) pedigrees of clams.

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Physiological Function and Metabolism of Free D-Alanine in Aquatic Animals

Cited by 87 publications

References 47 publications

An Expanded Transposon Mutant Library Reveals that Vibrio fischeri δ-Aminolevulinate Auxotrophs Can Colonize Euprymna scolopes

An Expanded Transposon Mutant Library Reveals that Vibrio fischeri δ-Aminolevulinate Auxotrophs Can Colonize Euprymna scolopes

Benzo(a)pyrene-induced metabolic responses in Manila clam Ruditapes philippinarum by proton nuclear magnetic resonance (1H NMR) based metabolomics

Differential toxicological effects induced by mercury in gills from three pedigrees of Manila clam Ruditapes philippinarum by NMR-based metabolomics

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