Evidence map›Paper›PMID 22407692›Full record

ArticleApplied and environmental microbiology2012

Characterization of the intracellular glutamate decarboxylase system: analysis of its function, transcription, and role in the acid resistance of various strains of Listeria monocytogenes.

Kimon-Andreas G Karatzas, Laura Suur, Conor P O'Byrne

Open access · bronzeAbstract read
In one paragraph

Article in Applied and environmental microbiology, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 34 papers.

0numbers the graph read from it
0cells of the map it votes in
34citing papers in PubMed
8.9field-weighted citation impact, top 2% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

34 citing papers in PubMed, 82 citations in OpenAlex.

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  7. Foods (Basel, Switzerland) · 2025
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  8. Cloning, expression, purification, and characterization of glutamate decarboxylase (Rv3432c) from Mycobacterium tuberculosis.International microbiology : the official journal of the Spanish Society for Microbiology · 2025
    Article
  9. Foods (Basel, Switzerland) · 2025
    Review
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  11. Unveiling the persistent threat: recent insights intoJournal of food science and technology · 2024
    Review
  12. Survival strategies ofFood science and biotechnology · 2023
    Review
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  18. Organic Acid Exposure Enhances Virulence in SomeFrontiers in microbiology · 2021
    Article
  19. Review
  20. Pathogens (Basel, Switzerland) · 2020
    Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

3 authors at 1 institution in 1 country.

Kimon-Andreas G KaratzasBacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland, Galway, Galway, Ireland. karatzas@hotmail.co.uk
Laura Suur
Conor P O'Byrne
Ollscoil na Gaillimhe – University of Galway · IE

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

The glutamate decarboxylase (GAD) system is important for the acid resistance of Listeria monocytogenes. We previously showed that under acidic conditions, glutamate (Glt)/γ-aminobutyrate (GABA) antiport is impaired in minimal media but not in rich ones, like brain heart infusion. Here we demonstrate that this behavior is more complex and it is subject to strain and medium variation. Despite the impaired Glt/GABA antiport, cells accumulate intracellular GABA (GABA(i)) as a standard response against acid in any medium, and this occurs in all strains tested. Since these systems can occur independently of one another, we refer to them as the extracellular (GAD(e)) and intracellular (GAD(i)) systems. We show here that GAD(i) contributes to acid resistance since in a ΔgadD1D2 mutant, reduced GABA(i) accumulation coincided with a 3.2-log-unit reduction in survival at pH 3.0 compared to that of wild-type strain LO28. Among 20 different strains, the GAD(i) system was found to remove 23.11% ± 18.87% of the protons removed by the overall GAD system. Furthermore, the GAD(i) system is activated at milder pH values (4.5 to 5.0) than the GAD(e) system (pH 4.0 to 4.5), suggesting that GAD(i) is the more responsive of the two and the first line of defense against acid. Through functional genomics, we found a major role for GadD2 in the function of GAD(i), while that of GadD1 was minor. Furthermore, the transcription of the gad genes in three common reference strains (10403S, LO28, and EGD-e) during an acid challenge correlated well with their relative acid sensitivity. No transcriptional upregulation of the gadT2D2 operon, which is the most important component of the GAD system, was observed, while gadD3 transcription was the highest among all gad genes in all strains. In this study, we present a revised model for the function of the GAD system and highlight the important role of GAD(i) in the acid resistance of L. monocytogenes.

Indexed as

Gene Expression Regulation, BacterialStress, PhysiologicalAcidsCulture MediaDrug Resistance, Bacterialgamma-Aminobutyric AcidGene DeletionGlutamate DecarboxylaseListeria monocytogenesMicrobial ViabilityTranscription, GeneticAcidsCulture Mediagamma-Aminobutyric AcidGlutamate Decarboxylase

Identifiers

PMID22407692
PMCPMC3346379
OpenAlexW2017643621

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.