A nanocompartment system contributes to defense against oxidative stress in Mycobacterium tuberculosis

AbstractEncapsulin nanocompartments are an emerging class of prokaryotic protein-based organelles consisting of an encapsulin protein shell that encloses a protein cargo1. Genes encoding nanocompartments are widespread in bacteria and archaea, and recent works have characterized the biochemical function of several cargo enzymes2. However, the importance of these organelles to host physiology is poorly understood. Here, we report that the human pathogen Mycobacterium tuberculosis (Mtb) produces a nanocompartment that contains the dye-decolorizing peroxidase DypB. We show that this nanocompartment is important for the ability of Mtb to resist oxidative stress in low pH environments, including during infection of host cells and upon treatment with a clinically relevant antibiotic. Our findings are the first to implicate a nanocompartment in bacterial pathogenesis and reveal a new mechanism that Mtb uses to combat oxidative stress.

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Exploring the mitochondrial response to oxidative DNA damage in octocorals

10.7287/peerj.preprints.2770v1 ◽

2017 ◽

Author(s):

Gaurav G Shimpi ◽

Sergio Vargas ◽

Gert Wörheide

Keyword(s):

Climate Change ◽

Oxidative Stress ◽

Copy Number ◽

Low Ph ◽

Host Cells ◽

Climate Change Scenarios ◽

Gene Repertoire ◽

Mtdna Copy Number ◽

Mtdna Damage ◽

Ph Stress

Mitochondrial response to oxidative stress is intricately related to cellular homeostasis due to the high susceptibility of the mitochondrial genome to oxidative damage. Octocoral mitogenomes possess a unique DNA repair gene, mtMutS, potentially capable of counteracting the effects of oxidative stress induced mtDNA damage. Despite this unique feature, the response of octocoral mitochondria to increased oxidative stress remains unexplored. Here we explore the response of the octocoral Sinularia cf. cruciata to elevated temperature and low-pH stress and its ability to reverse acute oxidative mtDNA damage caused by exogenous agents like hydrogen peroxide (H2O2). The differential transcriptional response to these climate change-related stresses was recorded for two mtDNA-encoded genes and three stress biomarkers. Only HSP70 was significantly upregulated during thermal stress whereas significant reduction in the expression levels of HSP70, GPX, and COI was observed along with an increased number of mtMutS transcripts during low-pH stress. Damage to mtDNA was evident, accompanied by changes in mtDNA copy number. Damage caused by H2O2 toxicity was reversed within 5 hours and initial mtDNA copy number apparently influenced damage reversal. Our results indicate that different stress-specific resilience strategies are used by this octocoral species and its mitochondria to reverse oxidative stress and associated mtDNA damage. These experiments provide the first account on the response of octocoral mitochondria with its unique gene repertoire among animals to different stressors and highlight its potential role in conferring resilience to the host cells during different climate change scenarios.

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Rv0180c contributes to Mycobacterium tuberculosis cell shape and to infectivity in mice and macrophages

PLoS Pathogens ◽

10.1371/journal.ppat.1010020 ◽

2021 ◽

Vol 17 (11) ◽

pp. e1010020

Author(s):

Delphine Payros ◽

Henar Alonso ◽

Wladimir Malaga ◽

Arnaud Volle ◽

Serge Mazères ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Cell Shape ◽

Cell Envelope ◽

Membrane Receptors ◽

Host Cells ◽

Wild Type ◽

Genes Encoding ◽

The Difference ◽

Complement Receptor 3 ◽

New Perspective

Mycobacterium tuberculosis, the main causative agent of human tuberculosis, is transmitted from person to person via small droplets containing very few bacteria. Optimizing the chance to seed in the lungs is therefore a major adaptation to favor survival and dissemination in the human population. Here we used TnSeq to identify genes important for the early events leading to bacterial seeding in the lungs. Beside several genes encoding known virulence factors, we found three new candidates not previously described: rv0180c, rv1779c and rv1592c. We focused on the gene, rv0180c, of unknown function. First, we found that deletion of rv0180c in M. tuberculosis substantially reduced the initiation of infection in the lungs of mice. Next, we established that Rv0180c enhances entry into macrophages through the use of complement-receptor 3 (CR3), a major phagocytic receptor for M. tuberculosis. Silencing CR3 or blocking the CR3 lectin site abolished the difference in entry between the wild-type parental strain and the Δrv0180c::km mutant. However, we detected no difference in the production of both CR3-known carbohydrate ligands (glucan, arabinomannan, mannan), CR3-modulating lipids (phthiocerol dimycocerosate), or proteins in the capsule of the Δrv0180c::km mutant in comparison to the wild-type or complemented strains. By contrast, we established that Rv0180c contributes to the functionality of the bacterial cell envelope regarding resistance to toxic molecule attack and cell shape. This alteration of bacterial shape could impair the engagement of membrane receptors that M. tuberculosis uses to invade host cells, and open a new perspective on the modulation of bacterial infectivity.

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Exploring the mitochondrial response to oxidative DNA damage in octocorals

10.7287/peerj.preprints.2770 ◽

2017 ◽

Author(s):

Gaurav G Shimpi ◽

Sergio Vargas ◽

Gert Wörheide

Keyword(s):

Climate Change ◽

Oxidative Stress ◽

Copy Number ◽

Low Ph ◽

Host Cells ◽

Climate Change Scenarios ◽

Gene Repertoire ◽

Mtdna Copy Number ◽

Mtdna Damage ◽

Ph Stress

Mitochondrial response to oxidative stress is intricately related to cellular homeostasis due to the high susceptibility of the mitochondrial genome to oxidative damage. Octocoral mitogenomes possess a unique DNA repair gene, mtMutS, potentially capable of counteracting the effects of oxidative stress induced mtDNA damage. Despite this unique feature, the response of octocoral mitochondria to increased oxidative stress remains unexplored. Here we explore the response of the octocoral Sinularia cf. cruciata to elevated temperature and low-pH stress and its ability to reverse acute oxidative mtDNA damage caused by exogenous agents like hydrogen peroxide (H2O2). The differential transcriptional response to these climate change-related stresses was recorded for two mtDNA-encoded genes and three stress biomarkers. Only HSP70 was significantly upregulated during thermal stress whereas significant reduction in the expression levels of HSP70, GPX, and COI was observed along with an increased number of mtMutS transcripts during low-pH stress. Damage to mtDNA was evident, accompanied by changes in mtDNA copy number. Damage caused by H2O2 toxicity was reversed within 5 hours and initial mtDNA copy number apparently influenced damage reversal. Our results indicate that different stress-specific resilience strategies are used by this octocoral species and its mitochondria to reverse oxidative stress and associated mtDNA damage. These experiments provide the first account on the response of octocoral mitochondria with its unique gene repertoire among animals to different stressors and highlight its potential role in conferring resilience to the host cells during different climate change scenarios.

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A Mycobacterium tuberculosis effector targets mitochondrion, controls energy metabolism and limits cytochrome c exit

10.1101/2021.01.31.428746 ◽

2021 ◽

Author(s):

Marianne Martin ◽

Angelique deVisch ◽

Philippe Barthe ◽

Obolbek Turapov ◽

Talip Aydogan ◽

...

Keyword(s):

Oxidative Stress ◽

Mycobacterium Tuberculosis ◽

Cytochrome C ◽

Metabolic Reprogramming ◽

Host Cells ◽

Intermembrane Space ◽

Phagocytic Cells ◽

Atp Production ◽

Host Cell Response ◽

Host Metabolism

AbstractHost metabolism reprogramming is a key feature of Mycobacterium tuberculosis (Mtb) infection that enables the survival of this pathogen within phagocytic cells and modulates the immune response facilitating the spread of the tuberculosis disease. Here, we demonstrate that a previously uncharacterized secreted protein from Mtb, Rv1813c manipulates the host metabolism by targeting mitochondria. When expressed in eukaryotic cells, the protein is delivered to the mitochondrial intermembrane space and enhances host ATP production by boosting the oxidative phosphorylation metabolic pathway. Furthermore, Rv1813c appears to differentially modulate the host cell response to oxidative stress. Expression of Rv1813 in host cells inhibits the release of cytochrome c from mitochondria, an early apoptotic event, in response to short-term oxidative stress. However, Rv1813c expressing cells showed increased sensitivity to prolonged stress. This study reveals a novel class of mitochondria targeting effectors from Mtb and opens new research directions on host metabolic reprogramming and apoptosis control.

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Analysis of genetic polymorphisms affecting the four phospholipase C (plc) genes in Mycobacterium tuberculosis complex clinical isolates

Microbiology ◽

10.1099/mic.0.26778-0 ◽

2004 ◽

Vol 150 (4) ◽

pp. 967-978 ◽

Cited By ~ 25

Author(s):

C. Viana-Niero ◽

P. E. de Haas ◽

D. van Soolingen ◽

S. C. Leão

Keyword(s):

Mycobacterium Tuberculosis ◽

Phospholipase C ◽

Genetic Polymorphisms ◽

Blot Hybridization ◽

Southern Blot Hybridization ◽

Clinical Isolates ◽

Significant Similarity ◽

Genomic Deletions ◽

Genes Encoding ◽

Mycobacterium Africanum

The Mycobacterium tuberculosis genome contains four highly related genes which present significant similarity to Pseudomonas aeruginosa genes encoding phospholipase C enzymes. Three of these genes, plcA, plcB and plcC, are organized in tandem (locus plcABC). The fourth gene, plcD, is located in a different region. This study investigates variations in plcABC and plcD genes in clinical isolates of M. tuberculosis, Mycobacterium africanum and ‘Mycobacterium canettii’. Genetic polymorphisms were examined by PCR, Southern blot hybridization, sequence analysis and RT-PCR. Seven M. tuberculosis isolates contain insertions of IS6110 elements within plcA, plcC or plcD. In 19 of 25 M. tuberculosis isolates examined, genomic deletions were identified, resulting in loss of parts of genes or complete genes from the plcABC and/or plcD loci. Partial plcD deletion was observed in one M. africanum isolate. In each case, deletions were associated with the presence of a copy of the IS6110 element and in all occurrences IS6110 was transposed in the same orientation. A mechanism of deletion resulting from homologous recombination of two copies of IS6110 was recognized in a group of genetically related M. tuberculosis isolates. Five M. tuberculosis isolates presented major polymorphisms in the plcABC and plcD regions, along with loss of expression competence that affected all four plc genes. Phospholipase C is a well-known bacterial virulence factor. The precise role of phospholipase C in the pathogenicity of M. tuberculosis is unknown, but considering the potential importance that the plc genes may have in the virulence of the tubercle bacillus, the study of isolates cultured from patients with active tuberculosis bearing genetic variations affecting these genes may provide insights into the significance of phospholipase C enzymes for tuberculosis pathogenicity.

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A novel putative microtubule-associated protein is involved in arbuscule development during arbuscular mycorrhiza formation

Plant and Cell Physiology ◽

10.1093/pcp/pcaa159 ◽

2021 ◽

Author(s):

Tania Ho-Plágaro ◽

Raúl Huertas ◽

María I Tamayo-Navarrete ◽

Elison Blancaflor ◽

Nuria Gavara ◽

...

Keyword(s):

Plant Root ◽

Arbuscular Mycorrhizal ◽

Host Cells ◽

Root Cells ◽

Filament Dynamics ◽

Fungal Structure ◽

Genes Encoding ◽

Associated Proteins ◽

Mycorrhizal Development

Abstract The formation of arbuscular mycorrhizal (AM) symbiosis requires plant root host cells to undergo major structural and functional reprogramming in order to house the highly branched AM fungal structure for the reciprocal exchange of nutrients. These morphological modifications are associated with cytoskeleton remodelling. However, molecular bases and the role of microtubules (MTs) and actin filament dynamics during AM formation are largely unknown. In this study, the tomato tsb gene, belonging to a Solanaceae group of genes encoding MT-associated proteins for pollen development, was found to be highly expressed in root cells containing arbuscules. At earlier stages of mycorrhizal development, tsb overexpression enhanced the formation of highly developed and transcriptionally active arbuscules, while tsb silencing hampers the formation of mature arbuscules and represses arbuscule functionality. However, at later stages of mycorrhizal colonization, tsb OE roots accumulate fully developed transcriptionally inactive arbuscules, suggesting that the collapse and turnover of arbuscules might be impaired by TSB accumulation. Imaging analysis of the MT cytoskeleton in cortex root cells overexpressing tsb revealed that TSB is involved in MT-bundling. Taken together, our results provide unprecedented insights into the role of novel MT-associated protein in MT rearrangements throughout the different stages of the arbuscule life cycle.

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Evolutionary Genetics of Mycobacterium tuberculosis and HIV-1: “The Tortoise and the Hare”

Microorganisms ◽

10.3390/microorganisms9010147 ◽

2021 ◽

Vol 9 (1) ◽

pp. 147

Author(s):

Ana Santos-Pereira ◽

Carlos Magalhães ◽

Pedro M. M. Araújo ◽

Nuno S. Osório

Keyword(s):

Genetic Diversity ◽

Drug Resistance ◽

Mycobacterium Tuberculosis ◽

Evolutionary Dynamics ◽

Evolutionary Genetics ◽

Host Cells ◽

Whole Genome Sequencing Data ◽

Host Immune System ◽

Viral Mutant ◽

Hiv 1

The already enormous burden caused by Mycobacterium tuberculosis and Human Immunodeficiency Virus type 1 (HIV-1) alone is aggravated by co-infection. Despite obvious differences in the rate of evolution comparing these two human pathogens, genetic diversity plays an important role in the success of both. The extreme evolutionary dynamics of HIV-1 is in the basis of a robust capacity to evade immune responses, to generate drug-resistance and to diversify the population-level reservoir of M group viral subtypes. Compared to HIV-1 and other retroviruses, M. tuberculosis generates minute levels of genetic diversity within the host. However, emerging whole-genome sequencing data show that the M. tuberculosis complex contains at least nine human-adapted phylogenetic lineages. This level of genetic diversity results in differences in M. tuberculosis interactions with the host immune system, virulence and drug resistance propensity. In co-infected individuals, HIV-1 and M. tuberculosis are likely to co-colonize host cells. However, the evolutionary impact of the interaction between the host, the slowly evolving M. tuberculosis bacteria and the HIV-1 viral “mutant cloud” is poorly understood. These evolutionary dynamics, at the cellular niche of monocytes/macrophages, are also discussed and proposed as a relevant future research topic in the context of single-cell sequencing.

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Oxidative Stress as a Possible Target in the Treatment of Toxoplasmosis: Perspectives and Ambiguities

International Journal of Molecular Sciences ◽

10.3390/ijms22115705 ◽

2021 ◽

Vol 22 (11) ◽

pp. 5705

Author(s):

Karolina Szewczyk-Golec ◽

Marta Pawłowska ◽

Roland Wesołowski ◽

Marcin Wróblewski ◽

Celestyna Mila-Kierzenkowska

Keyword(s):

Oxidative Stress ◽

Animal Studies ◽

Treatment Options ◽

Natural Antioxidants ◽

Redox Status ◽

Host Cells ◽

Common Disease ◽

Parasite Viability

Toxoplasma gondii is an apicomplexan parasite causing toxoplasmosis, a common disease, which is most typically asymptomatic. However, toxoplasmosis can be severe and even fatal in immunocompromised patients and fetuses. Available treatment options are limited, so there is a strong impetus to develop novel therapeutics. This review focuses on the role of oxidative stress in the pathophysiology and treatment of T. gondii infection. Chemical compounds that modify redox status can reduce the parasite viability and thus be potential anti-Toxoplasma drugs. On the other hand, oxidative stress caused by the activation of the inflammatory response may have some deleterious consequences in host cells. In this respect, the potential use of natural antioxidants is worth considering, including melatonin and some vitamins, as possible novel anti-Toxoplasma therapeutics. Results of in vitro and animal studies are promising. However, supplementation with some antioxidants was found to promote the increase in parasitemia, and the disease was then characterized by a milder course. Undoubtedly, research in this area may have a significant impact on the future prospects of toxoplasmosis therapy.

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Inhibition of Dermatophyte Fungi by Australian Jarrah Honey

Pathogens ◽

10.3390/pathogens10020194 ◽

2021 ◽

Vol 10 (2) ◽

pp. 194

Author(s):

Annabel Guttentag ◽

Krishothman Krishnakumar ◽

Nural Cokcetin ◽

Steven Hainsworth ◽

Elizabeth Harry ◽

...

Keyword(s):

Oxidative Stress ◽

Electron Microscopy ◽

Antifungal Activity ◽

Trichophyton Rubrum ◽

Microscopic Analysis ◽

Low Ph ◽

Eucalyptus Marginata ◽

Production Of Hydrogen ◽

Dermatophyte Species ◽

Scanning Electron

Superficial dermatophyte infections, commonly known as tineas, are the most prevalent fungal ailment and are increasing in incidence, leading to an interest in alternative treatments. Many floral honeys possess antimicrobial activity due to high sugar, low pH, and the production of hydrogen peroxide (H2O2) from the activity of the bee-derived enzyme glucose oxidase. Australian jarrah (Eucalyptus marginata) honey produces particularly high levels of H2O2 and has been found to be potently antifungal. This study characterized the activity of jarrah honey on fungal dermatophyte species. Jarrah honey inhibited dermatophytes with minimum inhibitory concentrations (MICs) of 1.5–3.5% (w/v), which increased to ≥25% (w/v) when catalase was added. Microscopic analysis found jarrah honey inhibited the germination of Trichophyton rubrum conidia and scanning electron microscopy of mature T. rubrum hyphae after honey treatment revealed bulging and collapsed regions. When treated hyphae were stained using REDOX fluorophores these did not detect any internal oxidative stress, suggesting jarrah honey acts largely on the hyphal surface. Although H2O2 appears critical for the antifungal activity of jarrah honey and its action on fungal cells, these effects persisted when H2O2 was eliminated and could not be replicated using synthetic honey spiked with H2O2, indicating jarrah honey contains agents that augment antifungal activity.

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