Mechanisms by which Human Macrophages Resist Intracellular Growth of Listeria Monocytogenes: Studies with a Redox Reagent Active in Leprosy and Experimental Tuberculosis (B 663)

1971 ◽  
pp. 43-44
Author(s):  
M. J. Cline
Keyword(s):  
Listeria Monocytogenes ◽  
Intracellular Growth ◽  
Experimental Tuberculosis ◽  
Human Macrophages ◽  
Redox Reagent

scholarly journals Identification of Listeria monocytogenes Genes Contributing to Intracellular Replication by Expression Profiling and Mutant Screening

2006 ◽  
Vol 188 (2) ◽  
pp. 556-568 ◽  
Author(s):  
Biju Joseph ◽  
Karin Przybilla ◽  
Claudia Stühler ◽  
Kristina Schauer ◽  
Jörg Slaghuis ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Stress Proteins ◽  
Carbon Sources ◽  
Brain Heart Infusion ◽  
Nitrogen Sources ◽  
Pentose Phosphate ◽  
Intracellular Growth ◽  
Cell Infection ◽  
Phosphotransferase System ◽  
Isoleucine Leucine

ABSTRACT A successful transition of Listeria monocytogenes from the extracellular to the intracellular environment requires a precise adaptation response to conditions encountered in the host milieu. Although many key steps in the intracellular lifestyle of this gram-positive pathogen are well characterized, our knowledge about the factors required for cytosolic proliferation is still rather limited. We used DNA microarray and real-time reverse transcriptase PCR analyses to investigate the transcriptional profile of intracellular L. monocytogenes following epithelial cell infection. Approximately 19% of the genes were differentially expressed by at least 1.6-fold relative to their level of transcription when grown in brain heart infusion medium, including genes encoding transporter proteins essential for the uptake of carbon and nitrogen sources, factors involved in anabolic pathways, stress proteins, transcriptional regulators, and proteins of unknown function. To validate the biological relevance of the intracellular gene expression profile, a random mutant library of L. monocytogenes was constructed by insertion-duplication mutagenesis and screened for intracellular-growth-deficient strains. By interfacing the results of both approaches, we provide evidence that L. monocytogenes can use alternative carbon sources like phosphorylated glucose and glycerol and nitrogen sources like ethanolamine during replication in epithelial cells and that the pentose phosphate cycle, but not glycolysis, is the predominant pathway of sugar metabolism in the host environment. Additionally, we show that the synthesis of arginine, isoleucine, leucine, and valine, as well as a species-specific phosphoenolpyruvate-dependent phosphotransferase system, play a major role in the intracellular growth of L. monocytogenes.

scholarly journals CD36-Mediated Uptake of Surfactant Lipids by Human Macrophages Promotes Intracellular Growth ofMycobacterium tuberculosis

2016 ◽  
Vol 197 (12) ◽  
pp. 4727-4735 ◽  
Author(s):  
Claire E. Dodd ◽  
Charlie J. Pyle ◽  
Rebecca Glowinski ◽  
Murugesan V. S. Rajaram ◽  
Larry S. Schlesinger
Keyword(s):  
Intracellular Growth ◽  
Human Macrophages ◽  
Ofmycobacterium Tuberculosis

scholarly journals β-Glucans inhibit intracellular growth of Mycobacterium bovis BCG but not virulent Mycobacterium tuberculosis in human macrophages

2011 ◽  
Vol 51 (4) ◽  
pp. 233-242 ◽  
Author(s):  
Bret E. Betz ◽  
Abul K. Azad ◽  
Jessica D. Morris ◽  
Murugesan V.S. Rajaram ◽  
Larry S. Schlesinger
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Bovis ◽  
Intracellular Growth ◽  
Human Macrophages ◽  
Mycobacterium Bovis Bcg

scholarly journals A non-catalytic histidine residue influences the function of the metalloprotease of Listeria monocytogenes

Microbiology ◽  
2014 ◽  
Vol 160 (1) ◽  
pp. 142-148 ◽  
Author(s):  
Brian M. Forster ◽  
Alan Pavinski Bitar ◽  
Hélène Marquis
Keyword(s):  
Cell Wall ◽  
Listeria Monocytogenes ◽  
Amino Acid ◽  
Positive Charge ◽  
Bacterial Pathogen ◽  
Histidine Residue ◽  
Amino Acid Residues ◽  
Intracellular Growth ◽  
N Terminus ◽  
Membrane Bound

Mpl, a thermolysin-like metalloprotease, and PC-PLC, a phospholipase C, are synthesized as proenzymes by the intracellular bacterial pathogen Listeria monocytogenes. During intracellular growth, L. monocytogenes is temporarily confined in a membrane-bound vacuole whose acidification leads to Mpl autolysis and Mpl-mediated cleavage of the PC-PLC N-terminal propeptide. Mpl maturation also leads to the secretion of both Mpl and PC-PLC across the bacterial cell wall. Previously, we identified negatively charged and uncharged amino acid residues within the N terminus of the PC-PLC propeptide that influence the ability of Mpl to mediate the maturation of PC-PLC, suggesting that these residues promote the interaction of the PC-PLC propeptide with Mpl. In the present study, we identified a non-catalytic histidine residue (H226) that influences Mpl secretion across the cell wall and its ability to process PC-PLC. Our results suggest that a positive charge at position 226 is required for Mpl functions other than autolysis. Based on the charge requirement at this position, we hypothesize that this residue contributes to the interaction of Mpl with the PC-PLC propeptide.

scholarly journals Francisella tularensisSchu S4 O-Antigen and Capsule Biosynthesis Gene Mutants Induce Early Cell Death in Human Macrophages

2010 ◽  
Vol 79 (2) ◽  
pp. 581-594 ◽  
Author(s):  
Stephen R. Lindemann ◽  
Kaitian Peng ◽  
Matthew E. Long ◽  
Jason R. Hunt ◽  
Michael A. Apicella ◽  
...  
Keyword(s):  
Cell Death ◽  
High Throughput Screening ◽  
Capsular Polysaccharide ◽  
Virulent Strain ◽  
Wild Type ◽  
Intracellular Growth ◽  
Human Macrophages ◽  
Polysaccharide Biosynthesis ◽  
O Antigen ◽  
Schu S4

ABSTRACTFrancisella tularensisis capable of rampant intracellular growth and causes a potentially fatal disease in humans. Whereas many mutational studies have been performed with avirulent strains ofFrancisella, relatively little has been done with strains that cause human disease. We generated a near-saturating transposon library in the virulent strain Schu S4, which was subjected to high-throughput screening by transposon site hybridization through primary human macrophages, negatively selecting 202 genes. Of special note were genes in a locus of theFrancisellachromosome,FTT1236,FTT1237, andFTT1238. Mutants with mutations in these genes demonstrated significant sensitivity to complement-mediated lysis compared with wild-type Schu S4 and exhibited marked defects in O-antigen and capsular polysaccharide biosynthesis. In the absence of complement, these mutants were phagocytosed more efficiently by macrophages than wild-type Schu S4 and were capable of phagosomal escape but exhibited reduced intracellular growth. Microscopic and quantitative analyses of macrophages infected with mutant bacteria revealed that these macrophages exhibited signs of cell death much earlier than those infected with Schu S4. These data suggest thatFTT1236,FTT1237, andFTT1238are important for polysaccharide biosynthesis and that theFrancisellaO antigen, capsule, or both are important for avoiding the early induction of macrophage death and the destruction of the replicative niche.

scholarly journals Listeria monocytogenes σHContributes to Expression of Competence Genes and Intracellular Growth

2016 ◽  
Vol 198 (8) ◽  
pp. 1207-1217 ◽  
Author(s):  
Veronica Medrano Romero ◽  
Kazuya Morikawa
Keyword(s):  
Transcription Factor ◽  
Listeria Monocytogenes ◽  
Sigma Factor ◽  
Physiological Role ◽  
Population Level ◽  
Alternative Sigma Factor ◽  
Intracellular Growth ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Regulation Scheme

ABSTRACTThe alternative sigma factor σHhas two functions in Gram-positive bacteria: it regulates sporulation and the development of genetic competence.Listeria monocytogenesis a nonsporulating species in which competence has not yet been detected. Nevertheless, the main competence regulators and a series of orthologous genes that form the competence machinery are present in its genome; some of the competence genes play a role in optimal phagosomal escape. In this study, strains overexpressing σHand strains with a σHdeletion were used to elucidate the contribution of σHto the expression of the competence machinery genes inL. monocytogenes. Gene expression analysis showed that σHis, indeed, involved incomGandcomEregulation. Unexpectedly, we observed a unique regulation scheme in which σHand the transcription factor ComK were involved. Population-level analysis showed that even with the overexpression of both factors, only a fraction of the cells expressed the competence machinery genes. Although we could not detect competence, σHwas crucial for phagosomal escape, which implies that this alternative sigma factor has specifically evolved to regulate theL. monocytogenesintracellular life cycle.IMPORTANCEListeria monocytogenescan be an intracellular pathogen capable of causing serious infections in humans and animal species. Recently, the competence machinery genes were described as being necessary for optimal phagosomal escape, in which the transcription factor ComK plays an important role. On the other hand, our previous phylogenetic analysis suggested that the alternative sigma factor σHmight play a role in the regulation of competence genes. The present study shows that some of the competence genes belong to the σHregulon and, importantly, that σHis essential for intracellular growth, implying a unique physiological role of σHamongFirmicutes.

scholarly journals Two Zinc Uptake Systems Contribute to the Full Virulence of Listeria monocytogenes during GrowthIn VitroandIn Vivo

2011 ◽  
Vol 80 (1) ◽  
pp. 14-21 ◽  
Author(s):  
David Corbett ◽  
Jiahui Wang ◽  
Stephanie Schuler ◽  
Gloria Lopez-Castejon ◽  
Sarah Glenn ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Zinc Uptake ◽  
Detectable Effect ◽  
Intracellular Growth ◽  
Content Type ◽  
Zinc Sensing ◽  
Identification And Characterization ◽  
Cell Deletion

ABSTRACTWe report here the identification and characterization of two zinc uptake systems, ZurAM and ZinABC, in the intracellular pathogenListeria monocytogenes. Transcription of both operons was zinc responsive and regulated by the zinc-sensing repressor Zur. Deletion of eitherzurAMorzinAhad no detectable effect on growth in defined media, but a doublezurAM zinAmutant was unable to grow in the absence of zinc supplementation. Deletion ofzinAhad no detectable effect on intracellular growth in HeLa epithelial cells. In contrast, growth of thezurAMmutant was significantly impaired in these cells, indicating the importance of the ZurAM system during intracellular growth. Notably, the deletion of bothzinAandzurAMseverely attenuated intracellular growth, with the double mutant being defective in actin-based motility and unable to spread from cell to cell. Deletion of eitherzurAMorzinAhad a significant effect on virulence in an oral mouse model, indicating that both zinc uptake systems are importantin vivoand establishing the importance of zinc acquisition during infection byL. monocytogenes. The presence of two zinc uptake systems may offer a mechanism by whichL. monocytogenescan respond to zinc deficiency within a variety of environments and during different stages of infection, with each system making distinct contributions under different stress conditions.

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