The Formation of Simple Fruiting Body-like Structures Associated with Sporulation under Aerobic Conditions in Clostridium acetobutylicum

Jones, David T.; Webster, J. R.; Woods, David R.

doi:10.1099/00221287-116-1-195

Cited by 6 publications

(3 citation statements)

References 4 publications

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“…Colonies of C. acetobutylicum Δ perR further increased in diameter when conditions were shifted from anaerobic to aerobic, and hence were able to maintain growth in ambient air, but only after anaerobic pre‐incubation. Earlier studies on structure and morphology of colonies of C. acetobutylicum revealed that they are covered by a proteineacous sheath (Jones et al. , 1980) providing additional protection against the deleterious effects of oxygen and possibly creating a microoxic environment sufficient for continued growth of perR ‐deleted cells.…”

Section: Discussionmentioning

confidence: 99%

PerR acts as a switch for oxygen tolerance in the strict anaerobe Clostridium acetobutylicum

Hillmann

Fischer

Saint-Prix

et al. 2008

Molecular Microbiology

108

104

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SummaryClostridia belong to those bacteria which are considered as obligate anaerobe, e.g. oxygen is harmful or lethal to these bacteria. Nevertheless, it is known that they can survive limited exposure to air, and often eliminate oxygen or reactive derivatives via NAD(P)Hdependent reduction. This system does apparently contribute to survival after oxidative stress, but is insufficient to establish long-term tolerance of aerobic conditions. Here we show that manipulation of the regulatory mechanism of this defence mechanism can trigger aerotolerance in the obligate anaerobe Clostridium acetobutylicum. Deletion of a peroxide repressor (PerR)-homologous protein resulted in prolonged aerotolerance, limited growth under aerobic conditions and rapid consumption of oxygen from an aerobic environment. The mutant strain also revealed higher resistance to H 2O2 and activities of NADH-dependent scavenging of H2O2 and organic peroxides in cell-free extracts increased by at least one order of magnitude. Several genes encoding the putative enzymes were upregulated and identified as members of the clostridial PerR regulon, including the heat shock protein Hsp21, a reverse rubrerythrin which was massively produced and became the most abundant protein in the absence of PerR. This multifunctional protein is proposed to play the crucial role in the oxidative stress defence.

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Section: Discussionmentioning

confidence: 99%

PerR acts as a switch for oxygen tolerance in the strict anaerobe Clostridium acetobutylicum

Hillmann

Fischer

Saint-Prix

et al. 2008

Molecular Microbiology

108

104

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“…A possible explanation for employing multiple signalling systems may lie in the complex life cycle of these organisms, which not only involves a shift in fermentation metabolism, but also endospore formation and, under certain conditions, fruiting body formation [36]. These are all phenotypes for which quorum sensing control has been demonstrated in other species.…”

Section: Discussionmentioning

confidence: 99%

RRNPP-type quorum sensing affects solvent formation and sporulation in Clostridium acetobutylicum

et al. 2020

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The strictly anaerobic bacterium Clostridium acetobutylicum is well known for its ability to convert sugars into organic acids and solvents, most notably the potential biofuel butanol. However, the regulation of its fermentation metabolism, in particular the shift from acid to solvent production, remains poorly understood. The aim of this study was to investigate whether cell–cell communication plays a role in controlling the timing of this shift or the extent of solvent formation. Analysis of the available C. acetobutylicum genome sequences revealed the presence of eight putative RRNPP-type quorum-sensing systems, here designated qssA to qssH, each consisting of an RRNPP-type regulator gene followed by a small open reading frame encoding a putative signalling peptide precursor. The identified regulator and signal peptide precursor genes were designated qsrA to qsrH and qspA to qspH, respectively. Triplicate regulator mutants were generated in strain ATCC 824 for each of the eight systems and screened for phenotypic changes. The qsrB mutants showed increased solvent formation during early solventogenesis and hence the QssB system was selected for further characterization. Overexpression of qsrB severely reduced solvent and endospore formation and this effect could be overcome by adding short synthetic peptides to the culture medium representing a specific region of the QspB signalling peptide precursor. In addition, overexpression of qspB increased the production of acetone and butanol and the initial (48 h) titre of heat-resistant endospores. Together, these findings establish a role for QssB quorum sensing in the regulation of early solventogenesis and sporulation in C. acetobutylicum .

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“…Finally, mathematical simulations of tumour growth show that under conditions of short oxygen supply, the morphology of the tumour is invasive, with small fingers or lobes protruding from the edge of the tumour body (Anderson et al 2006). This morphology of growth resembles that of colonies of anaerobic organisms, which produce typical flat spreading colonies with large spreading fans or lobes that grow out from the margins (Jones et al 1980).…”

Section: Hypoxia: the Optimal Environment For Cancer Cells And Lecamentioning

confidence: 99%

Mitochondria and the evolutionary roots of cancer

Dávila

Zamorano

2013

Phys. Biol.

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Cancer disease is inherent to, and widespread among, metazoans. Yet, some of the hallmarks of cancer such as uncontrolled cell proliferation, lack of apoptosis, hypoxia, fermentative metabolism and free cell motility (metastasis) are akin to a prokaryotic lifestyle, suggesting a link between cancer disease and evolution. In this hypothesis paper, we propose that cancer cells represent a phenotypic reversion to the earliest stage of eukaryotic evolution. This reversion is triggered by the dysregulation of the mitochondria due to cumulative oxidative damage to mitochondrial and nuclear DNA. As a result, the phenotype of normal, differentiated cells gradually reverts to the phenotype of a facultative anaerobic, heterotrophic cell optimized for survival and proliferation in hypoxic environments. This phenotype matches the phenotype of the last eukaryotic common ancestor (LECA) that resulted from the endosymbiosis between an α-proteobacteria (which later became the mitochondria) and an archaebacteria. As such, the evolution of cancer within one individual can be viewed as a recapitulation of the evolution of the eukaryotic cell from fully differentiated cells to LECA. This evolutionary model of cancer is compatible with the current understanding of the disease, and explains the evolutionary basis for most of the hallmarks of cancer, as well as the link between the disease and aging. It could also open new avenues for treatment directed at reestablishing the synergy between the mitochondria and the cancerous cell.

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The Formation of Simple Fruiting Body-like Structures Associated with Sporulation under Aerobic Conditions in Clostridium acetobutylicum

Cited by 6 publications

References 4 publications

PerR acts as a switch for oxygen tolerance in the strict anaerobe Clostridium acetobutylicum

PerR acts as a switch for oxygen tolerance in the strict anaerobe Clostridium acetobutylicum

RRNPP-type quorum sensing affects solvent formation and sporulation in Clostridium acetobutylicum

Mitochondria and the evolutionary roots of cancer

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