scholarly journals Role of gliotoxin in the symbiotic and pathogenic interactions of Trichoderma virens

Microbiology ◽  
2014 ◽  
Vol 160 (10) ◽  
pp. 2319-2330 ◽  
Author(s):  
Walter A. Vargas ◽  
Prasun K. Mukherjee ◽  
David Laughlin ◽  
Aric Wiest ◽  
Maria E. Moran-Diez ◽  
...  
Keyword(s):  
Fungal Pathogen ◽  
Gene Disruption ◽  
Galleria Mellonella ◽  
Pythium Ultimum ◽  
Trichoderma Virens ◽  
Human Pathogen ◽  
Opportunistic Human Pathogen ◽  
Confrontation Assay ◽  
Wax Moth

Using a gene disruption strategy, we generated mutants in the gliP locus of the plant-beneficial fungus Trichoderma virens that were no longer capable of producing gliotoxin. Phenotypic assays demonstrated that the gliP-disrupted mutants grew faster, were more sensitive to oxidative stress and exhibited a sparse colony edge compared with the WT strain. In a plate confrontation assay, the mutants deficient in gliotoxin production were ineffective as mycoparasites against the oomycete, Pythium ultimum, and the necrotrophic fungal pathogen, Sclerotinia sclerotiorum, but retained mycoparasitic ability against Rhizoctonia solani. Biocontrol assays in soil showed that the mutants were incapable of protecting cotton seedlings from attack by P. ultimum, against which the WT strain was highly effective. The mutants, however, were as effective as the WT strain in protecting cotton seedlings against R. solani. Loss of gliotoxin production also resulted in a reduced ability of the mutants to attack the sclerotia of S. sclerotiorum compared with the WT. The addition of exogenous gliotoxin to the sclerotia colonized by the mutants partially restored their degradative abilities. Interestingly, as in Aspergillus fumigatus, an opportunistic human pathogen, gliotoxin was found to be involved in pathogenicity of T. virens against larvae of the wax moth, Galleria mellonella. The loss of gliotoxin production in T. virens was restored by complementation with the gliP gene from A. fumigatus. We have, thus, demonstrated that the putative gliP cluster of T. virens is responsible for the biosynthesis of gliotoxin, and gliotoxin is involved in mycoparasitism and biocontrol properties of this plant-beneficial fungus.

scholarly journals A Candida parapsilosis Overexpression Collection Reveals Genes Required for Pathogenesis

2021 ◽  
Vol 7 (2) ◽  
pp. 97
Author(s):  
Sára E. Pál ◽  
Renáta Tóth ◽  
Joshua D. Nosanchuk ◽  
Csaba Vágvölgyi ◽  
Tibor Németh ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Deletion Mutant ◽  
Candida Parapsilosis ◽  
Galleria Mellonella ◽  
Mutant Library ◽  
Human Pathogen ◽  
Opportunistic Human Pathogen ◽  
Mutant Collection

Relative to the vast data regarding the virulence mechanisms of Candida albicans, there is limited knowledge on the emerging opportunistic human pathogen Candida parapsilosis. The aim of this study was to generate and characterize an overexpression mutant collection to identify and explore virulence factors in C. parapsilosis. With the obtained mutants, we investigated stress tolerance, morphology switch, biofilm formation, phagocytosis, and in vivo virulence in Galleria mellonella larvae and mouse models. In order to evaluate the results, we compared the data from the C. parapsilosis overexpression collection analysis to the results derived from previous deletion mutant library characterizations. Of the 37 overexpression C. parapsilosis mutants, we identified eight with altered phenotypes compared to the controls. This work is the first report to identify CPAR2_107240, CPAR2_108840, CPAR2_302400, CPAR2_406400, and CPAR2_602820 as contributors to C. parapsilosis virulence by regulating functions associated with host-pathogen interactions and biofilm formation. Our findings also confirmed the role of CPAR2_109520, CPAR2_200040, and CPAR2_500180 in pathogenesis. This study was the first attempt to use an overexpression strategy to systematically assess gene function in C. parapsilosis, and our results demonstrate that this approach is effective for such investigations.

scholarly journals Use of the Galleria mellonella Caterpillar as a Model Host To Study the Role of the Type III Secretion System in Pseudomonas aeruginosa Pathogenesis

2003 ◽  
Vol 71 (5) ◽  
pp. 2404-2413 ◽  
Author(s):  
Sachiko Miyata ◽  
Monika Casey ◽  
Dara W. Frank ◽  
Frederick M. Ausubel ◽  
Eliana Drenkard
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Type Iii Secretion ◽  
Galleria Mellonella ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Effector Proteins ◽  
Triple Mutant ◽  
Type Iii ◽  
Wax Moth

ABSTRACT Nonvertebrate model hosts represent valuable tools for the study of host-pathogen interactions because they facilitate the identification of bacterial virulence factors and allow the discovery of novel components involved in host innate immune responses. In this report, we determined that the greater wax moth caterpillar Galleria mellonella is a convenient nonmammalian model host for study of the role of the type III secretion system (TTSS) in Pseudomonas aeruginosa pathogenesis. Based on the observation that a mutation in the TTSS pscD gene of P. aeruginosa strain PA14 resulted in a highly attenuated virulence phenotype in G. mellonella, we examined the roles of the four known effector proteins of P. aeruginosa (ExoS, ExoT, ExoU, and ExoY) in wax moth killing. We determined that in P. aeruginosa strain PA14, only ExoT and ExoU play a significant role in G. mellonella killing. Strain PA14 lacks the coding sequence for the ExoS effector protein and does not seem to express ExoY. Moreover, using ΔexoU ΔexoY, ΔexoT ΔexoY, and ΔexoT ΔexoU double mutants, we determined that individual translocation of either ExoT or ExoU is sufficient to obtain nearly wild-type levels of G. mellonella killing. On the other hand, data obtained with a ΔexoT ΔexoU ΔexoY triple mutant and a ΔpscD mutant suggested that additional, as-yet-unidentified P. aeruginosa components of type III secretion are involved in virulence in G. mellonella. A high level of correlation between the results obtained in the G. mellonella model and the results of cytopathology assays performed with a mammalian tissue culture system validated the use of G. mellonella for the study of the P. aeruginosa TTSS.

scholarly journals Comparison of different extraction kits to isolate microRNA fromGalleria mellonella(wax moth) larvae infected withMetarhizium brunneum(ARSEF4556)

2019 ◽  
Author(s):  
Muneefah A. Alenezi ◽  
Tariq M. Butt ◽  
Daniel C. Eastwood
Keyword(s):  
Fungal Pathogens ◽  
High Throughput Sequencing ◽  
Galleria Mellonella ◽  
Host Tissue ◽  
Tissue Cultures ◽  
Complex Environments ◽  
Infected Insect ◽  
Sequencing And Expression ◽  
Wax Moth

ABSTRACTMicroRNAs (miRNAs) play an important role in regulating gene expression and are involved in developmental processes in animals, plants and fungi. To understand the role of miRNAs in a biological system, it is important to optimise the extraction procedures to obtain high quality and quantity nucleic acid that enable high throughput sequencing and expression analysis. Numerous kit-based miRNA extraction protocols have been optimised generally to single cell or tissue cultures. Fungi, however, often occupy physically and chemically complex environments which miRNA make extraction challenging, such as fungal pathogens interacting within plant or animal host tissue. We used aGalleria mellonella(wax moth) larvae and entomopathogenic fungusMetarhizium brunneum ARSEF 4556host/pathogen model to compare commercially available miRNA extraction kits (Invitrogen PureLink™ miRNA Isolation Kit, Ambion mirVana™miRNA Isolation Kit and Norgen microRNA purification Kit). Our results showed reproducible and significant differences in miRNAs extraction between the kits, with the Invitrogen PureLink™ miRNA Isolation protocol demonstrating the best performance in terms of miRNA quantity, quality and integrity isolated from fungus-infected insect tissue.

scholarly journals Severe Acute Infection Due to Serratia marcescens Causing Respiratory Distress in An Immunocompetent Adult

2016 ◽  
Vol 54 (2) ◽  
pp. 134-136 ◽  
Author(s):  
Pablo Ruiz-Sada ◽  
Mikel Escalante ◽  
Eva Lizarralde
Keyword(s):  
Risk Factors ◽  
Respiratory Distress ◽  
Serratia Marcescens ◽  
Distress Syndrome ◽  
Acute Infection ◽  
Human Pathogen ◽  
Immunocompetent Adult ◽  
Uncommon Presentation ◽  
Opportunistic Human Pathogen

AbstractThe role ofSerratia marcescenschanged from a harmless saprophytic microorganism to an important opportunistic human pathogen. It often causes nosocomial device-associated outbreaks and rarely serious invasive community acquired infections. We present a case of a community-acquiredSerratia marcescensbacteremia leading to Respiratory Distress Syndrome in a previously healthy 51-year-old man without identifiable risk factors. Full recovery was achieved with solely medical treatment and observation in ICU during three days. To our knowledge it is an extremely uncommon presentation and just few cases have been previously reported in the literature.

scholarly journals The Protective Role of 1,8-Dihydroxynaphthalene–Melanin on Conidia of the Opportunistic Human Pathogen Aspergillus fumigatus Revisited: No Role in Protection against Hydrogen Peroxide and Superoxides

mSphere ◽  
2022 ◽  
Author(s):  
E. M. Keizer ◽  
I. D. Valdes ◽  
B. L. McCann ◽  
E. M. Bignell ◽  
H. A. B. Wösten ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Aspergillus Fumigatus ◽  
Protective Role ◽  
Oxygen Species ◽  
Human Pathogen ◽  
Opportunistic Pathogens ◽  
Green Pigment ◽  
Content Type ◽  
Opportunistic Human Pathogen

Opportunistic pathogens like Aspergillus fumigatus have strategies to protect themselves against reactive oxygen species like hydrogen peroxides and superoxides that are produced by immune cells. DHN-melanin is the green pigment on conidia of Aspergillus fumigatus and more than 2 decades ago was reported to protect conidia against hydrogen peroxide.

scholarly journals Tvbgn3, a β-1,6-Glucanase from the Biocontrol Fungus Trichoderma virens, Is Involved in Mycoparasitism and Control of Pythium ultimum

2006 ◽  
Vol 72 (12) ◽  
pp. 7661-7670 ◽  
Author(s):  
Slavica Djonović ◽  
Maria J. Pozo ◽  
Charles M. Kenerley
Keyword(s):  
Cell Walls ◽  
Gene Expression Analysis ◽  
Pythium Ultimum ◽  
Trichoderma Virens ◽  
Wild Type ◽  
Fungal Cell ◽  
Biocontrol Activity ◽  
And Control ◽  
Plant Bioassays

ABSTRACT Even though β-1,6-glucanases have been purified from several filamentous fungi, the physiological function has not been conclusively established for any species. In the present study, the role of Tvbgn3, a β-1,6-glucanase from Trichoderma virens, was examined by comparison of wild-type (WT) and transformant strains in which Tvbgn3 was disrupted (GKO) or constitutively overexpressed (GOE). Gene expression analysis revealed induction of Tvbgn3 in the presence of host fungal cell walls, indicating regulation during mycoparasitism. Indeed, while deletion or overexpression of Tvbgn3 had no evident effect on growth and development, GOE and GKO strains showed an enhanced or reduced ability, respectively, to inhibit the growth of the plant pathogen Pythium ultimum compared to results with the WT. The relevance of this activity in the biocontrol ability of T. virens was confirmed in plant bioassays. Deletion of the gene resulted in levels of disease protection that were significantly reduced from WT levels, while GOE strains showed a significantly increased biocontrol capability. These results demonstrate the involvement of β-1,6-glucanase in mycoparasitism and its relevance in the biocontrol activity of T. virens, opening a new avenue for biotechnological applications.

scholarly journals Galleria mellonella as an alternative infection model for Yersinia pseudotuberculosis

Microbiology ◽  
2009 ◽  
Vol 155 (5) ◽  
pp. 1516-1522 ◽  
Author(s):  
Olivia L. Champion ◽  
Ian A. M. Cooper ◽  
Sarah L. James ◽  
Donna Ford ◽  
Andrey Karlyshev ◽  
...  
Keyword(s):  
Wild Type Strain ◽  
Yersinia Pseudotuberculosis ◽  
Galleria Mellonella ◽  
Infection Model ◽  
Phenotypic Properties ◽  
Infection Models ◽  
Insect Haemocytes ◽  
Increased Susceptibility ◽  
Wax Moth

We report that larvae of the wax moth (Galleria mellonella) are susceptible to infection with the human enteropathogen Yersinia pseudotuberculosis at 37 °C. Confocal microscopy demonstrated that in the initial stages of infection the bacteria were taken up into haemocytes. To evaluate the utility of this model for screening Y. pseudotuberculosis mutants we constructed and tested a superoxide dismutase C (sodC) mutant. This mutant showed increased susceptibility to superoxide, a key mechanism of killing in insect haemocytes and mammalian phagocytes. It showed reduced virulence in the murine yersiniosis infection model and in contrast to the wild-type strain IP32953 was unable to kill G. mellonella. The complemented mutant regained all phenotypic properties associated with SodC, confirming the important role of this metalloenzyme in two Y. pseudotuberculosis infection models.

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