Campylobacter jejuni Transcription and Iron Uptake
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Questions and Answers

What was the concentration of streptomycin where STM-sensitive growth was observed?

  • 1 – 8 μg/ml
  • 16 – 32 μg/ml
  • 0 – 1 μg/ml (correct)
  • 8 – 16 μg/ml

    • The ⌬1651–1656 and ⌬p19 mutants exhibited a bimodal growth phenotype.

    False

    What effect did iron supplementation have on the MICs of the mutants?

    Restored them to wild-type levels of 16 μg/ml.

    The wild-type strain of C. jejuni showed a bimodal growth phenotype under streptomycin stress at concentrations of _______.

    <p>0 to 8 μg/ml</p> Signup and view all the answers

    How did the cell viability of C. jejuni strains change after H2O2 addition in MH alone?

    <p>Decreased over time</p> Signup and view all the answers

    Match the mutant strains with their corresponding growth phenotype:

    <p>⌬1651–1656 = Monomodal growth ⌬p19 = Monomodal growth Wild-type = Bimodal growth Complemented strains = Bimodal growth</p> Signup and view all the answers

    There were no significant differences between the growth of the wild-type and mutant strains under oxidative stress.

    <p>False</p> Signup and view all the answers

    What was the role of iron(III) citrate in the study?

    <p>To supplement conditions under which C. jejuni was tested for growth.</p> Signup and view all the answers

    What temperature was C. jejuni incubated microaerobically for optimal growth?

    <p>38°C</p> Signup and view all the answers

    C. jejuni is primarily grown in Luria-Bertani broth for selection using kanamycin and chloramphenicol.

    <p>True</p> Signup and view all the answers

    What is the purpose of adding extracts to the culture media for C. jejuni?

    <p>To promote growth and biofilm formation.</p> Signup and view all the answers

    C. jejuni cells were cultured in ____ broth at an OD600 of 0.25 for RNA preparation.

    <p>MH-TV</p> Signup and view all the answers

    Match the following components with their respective roles in the experiment:

    <p>Cm = Selection antibiotic Km = Selection antibiotic MH-TV = Culture medium Extracts = Growth enhancement and biofilm formation</p> Signup and view all the answers

    What volume of extract was combined in the MH-TV culture for testing?

    <p>0.3 ml</p> Signup and view all the answers

    The planktonic cell concentration was measured from the surface of the liquid culture.

    <p>False</p> Signup and view all the answers

    How were the biofilms quantified in the experiment?

    <p>By dilution plating.</p> Signup and view all the answers

    Which gene showed the greatest reduction in expression after 5 hours?

    <p>C4-dicarboxylate ABC transporter</p> Signup and view all the answers

    The gene CJJ81176_0685 is associated with chemotaxis.

    <p>False</p> Signup and view all the answers

    What is the significance of a P value less than 0.05 in this context?

    <p>It indicates statistical significance of the gene expression changes.</p> Signup and view all the answers

    CJJ81176_0033 is the locus tag for the gene responsible for __________ synthesis.

    <p>glutamate</p> Signup and view all the answers

    Match the following genes with their functions:

    <p>CJJ81176_0184 = Hypothetical protein CJJ81176_0912 = Amino acid carrier protein CJJ81176_1350 = Fumarate reductase CJJ81176_1006 = Hypothetical protein</p> Signup and view all the answers

    Which gene product is a major antigenic peptide?

    <p>PEB3</p> Signup and view all the answers

    The locus tag CJJ81176_1656 codes for a thioredoxin family protein.

    <p>True</p> Signup and view all the answers

    What is the fold change of the gene CJJ81176_0315 after 20 minutes?

    <p>-3.0</p> Signup and view all the answers

    The gene CJJ81176_1386 is responsible for __________ reductase activity.

    <p>fumarate</p> Signup and view all the answers

    Which of the following genes is associated with sodium:alanine symporter function?

    <p>CJJ81176_0941</p> Signup and view all the answers

    What is the primary transcription start site for the 1649 –1656 genes located relative to the 1649 start codon?

    <p>54 bases upstream</p> Signup and view all the answers

    The genes 1648 and 1657 are considered part of the operon consisting of genes 1649 –1656.

    <p>False</p> Signup and view all the answers

    How many fully sequenced Campylobacter species contain components of the 1649 –1656 system?

    <p>22</p> Signup and view all the answers

    The homologous gene products of the 1649 –1656 system were most commonly found in members of the ______.

    <p>Proteobacteria</p> Signup and view all the answers

    Match the following bacterial genera with whether they carry the 1649 –1656 system on plasmids or chromosomes:

    <p>Escherichia = Plasmids Klebsiella = Plasmids Shigella = Plasmids Campylobacter = Chromosomes</p> Signup and view all the answers

    Which of the following species has not been associated with human illness?

    <p>C. avium</p> Signup and view all the answers

    The complete genome sequences of 33 phylogenetically diverse bacterial species showed homologues of genes 1649 –1656 exclusively in Actinobacteria.

    <p>False</p> Signup and view all the answers

    What is the distance in base pairs between gene 1648 and the start codon of gene 1649?

    <p>350</p> Signup and view all the answers

    Which gene product is associated with the function of aspartate ammonia-lyase?

    <p>aspA</p> Signup and view all the answers

    CJJ81176_1649 has a higher fold change than CJJ81176_1651.

    <p>True</p> Signup and view all the answers

    What is the fold change for the gene product associated with the 'putative oxidoreductase subunit' after 5 hours?

    <p>11.8</p> Signup and view all the answers

    CJJ81176_0885 is a type of ______.

    <p>cytochrome c</p> Signup and view all the answers

    Match the following gene products with their functions:

    <p>CJJ81176_1650 = Periplasmic iron binding protein CJJ81176_1391 = C4-dicarboxylate ABC transporter CJJ81176_1390 = Reactive intermediate/imine deaminase CJJ81176_0123 = Anaerobic C4-dicarboxylate membrane transporter DcuA</p> Signup and view all the answers

    Which locus tag shows the highest fold change after 20 minutes?

    <p>CJJ81176_0438</p> Signup and view all the answers

    The gene CJJ81176_1392 is associated with cystathionine β-lyase.

    <p>True</p> Signup and view all the answers

    What is the function of the gene product CJJ81176_1654?

    <p>ATP-binding protein</p> Signup and view all the answers

    CJJ81176_1393 encodes an ______.

    <p>adenylosuccinate lyase</p> Signup and view all the answers

    Which of the following genes is associated with anaerobic dimethyl sulfoxide reductase?

    <p>CJJ81176_1570</p> Signup and view all the answers

    Which of the following bacteria is associated with the case of enteritis in humans?

    <p>Campylobacter lanienae</p> Signup and view all the answers

    Aspartase (AspA) is essential for bacteria to grow under aerobic conditions.

    <p>False</p> Signup and view all the answers

    What is the primary function of the C4-dicarboxylate transporters in Campylobacter jejuni?

    <p>Transport of C4-dicarboxylates for metabolic processes</p> Signup and view all the answers

    ___ is a novel succinic-acid-producing strain from the bovine rumen.

    <p>Actinobacillus succinogenes sp.</p> Signup and view all the answers

    Match the following bacterial species with their notable characteristics:

    <p>Campylobacter jejuni = Amino acid-dependent growth Actinobacillus succinogenes = Succinic acid production Frischella perrara = Gammaproteobacterium from honeybee gut Campylobacter lanienae = Cause of enteritis in humans</p> Signup and view all the answers

    What role does AspB (Cj0762) play in Campylobacter jejuni?

    <p>It is essential for growth on glutamate.</p> Signup and view all the answers

    The complete genome sequence of Wolinella succinogenes has been analyzed.

    <p>True</p> Signup and view all the answers

    Identify the main focus of the 2014 study on bacterial metabolism referenced.

    <p>Bacterial methionine biosynthesis</p> Signup and view all the answers

    Study Notes

    Campylobacter jejuni Transcriptional Response

    • Campylobacter jejuni is a pathogenic bacterium causing gastroenteritis in humans. It's a common commensal in animals, particularly poultry.
    • RNA sequencing was used to study C. jejuni's response to human and chicken intestinal extracts.
    • C. jejuni's transcription was altered in response to extracts compared to medium alone. Key changes related to iron uptake, metabolism, chemotaxis, energy production & osmotic stress.
    • Exposure to human extracts resulted in higher expression of genes involved in respiration (fdhTU) and iron uptake systems (cfbpA, ceuB, chuC, 1649-1655).
    • Genes 1649-1656 and downstream overlapping gene 1656, show these genes are involved in iron scavenging and stress response in the human intestine.
    • Homologues of the 1649-1656 system are found in various bacterial species (including 21 associated with human disease).

    Iron Uptake System

    • Genes 1649 and 1650 (p19) encode an iron transporter and a periplasmic iron binding protein, respectively.
    • The 1651-1656 gene cluster is involved in C. jejuni’s iron scavenging.
    • A Δ1651-1656 deletion strain has an iron-sensitive phenotype and reduced growth in acidic environments.
    • This cluster is vital for optimal growth in iron-restricted environments, utilising human fecal extracts as iron sources.

    Host Intestinal Extracts

    • Human fecal extracts contain higher total iron content compared to chicken cecal extracts.
    • C. jejuni's response to human fecal extracts involved higher expression of iron uptake-related genes and formate dehydrogenase genes compared to chicken extracts.

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    Investigating Campylobacter jejuni Transcriptional Response to Host Intestinal Extracts - PDF

    Description

    Explore the transcriptional response of Campylobacter jejuni to human and chicken intestinal extracts. This quiz covers key changes in gene expression related to iron uptake, metabolism, and stress responses as revealed through RNA sequencing. Test your knowledge of the mechanisms that enable this pathogen to thrive in diverse environments.

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