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 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 Exopolysaccharide biosynthetic glycoside hydrolases can be utilized to disrupt and preventPseudomonas aeruginosabiofilms

2015 ◽  
Author(s):  
Perrin Baker ◽  
Preston J HIll ◽  
Brendan D Snarr ◽  
Noor Alnabelseya ◽  
Mathew J Pestrak ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Glycoside Hydrolases ◽  
Bacterial Biofilms ◽  
Human Pathogen ◽  
Host Defenses ◽  
Bacterial Exopolysaccharide ◽  
Opportunistic Human Pathogen ◽  
Potential Therapeutics

Bacterial biofilms are a significant medical challenge as they are recalcitrant to current therapeutic regimes. A key component of biofilm formation in the opportunistic human pathogenPseudomonas aeruginosais the biosynthesis of the exopolysaccharides Pel and Psl, which are involved in the formation and maintenance of the structural biofilm scaffold and protection against antimicrobials and host defenses. Given that the glycoside hydrolases - PelAhand PslGh- encoded in thepelandpslbiosynthetic operons, respectively, are utilized for in vivo exopolysaccharide processing, we reasoned that these would provide specificity to targetP. aeruginosabiofilms. Evaluating these enzymes as potential therapeutics, we demonstrate that these glycoside hydrolases selectively target and degrade the exopolysaccharide component of the biofilm matrix and that nanomolar concentrations of these enzymes can both prevent biofilm formation as well as rapidly disrupt preexisting biofilms in vitro. This treatment was effective against clinical and environmental P. aeruginosa isolates and reduced biofilm biomass by 58-94%. These non-cytotoxic enzymes potentiated antibiotics as the addition of either enzyme to a sub-lethal concentration of colistin reduced viable bacterial counts by 2.5 orders of magnitude. Additionally, PelAhwas able to increase neutrophil killing by ~50%. This work illustrates the feasibility and benefits of using bacterial exopolysaccharide biosynthetic glycoside hydrolases and synthetic biology to develop novel anti-biofilm therapeutics.

scholarly journals Acetylcholine Protects against Candida albicans Infection by Inhibiting Biofilm Formation and Promoting Hemocyte Function in a Galleria mellonella Infection Model

2015 ◽  
Vol 14 (8) ◽  
pp. 834-844 ◽  
Author(s):  
Ranjith Rajendran ◽  
Elisa Borghi ◽  
Monica Falleni ◽  
Federica Perdoni ◽  
Delfina Tosi ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Biofilm Formation ◽  
Galleria Mellonella ◽  
Inflammatory Responses ◽  
Fungal Infections ◽  
Infection Model ◽  
Content Type

ABSTRACT Both neuronal acetylcholine and nonneuronal acetylcholine have been demonstrated to modulate inflammatory responses. Studies investigating the role of acetylcholine in the pathogenesis of bacterial infections have revealed contradictory findings with regard to disease outcome. At present, the role of acetylcholine in the pathogenesis of fungal infections is unknown. Therefore, the aim of this study was to determine whether acetylcholine plays a role in fungal biofilm formation and the pathogenesis of Candida albicans infection. The effect of acetylcholine on C. albicans biofilm formation and metabolism in vitro was assessed using a crystal violet assay and phenotypic microarray analysis. Its effect on the outcome of a C. albicans infection, fungal burden, and biofilm formation were investigated in vivo using a Galleria mellonella infection model. In addition, its effect on modulation of host immunity to C. albicans infection was also determined in vivo using hemocyte counts, cytospin analysis, larval histology, lysozyme assays, hemolytic assays, and real-time PCR. Acetylcholine was shown to have the ability to inhibit C. albicans biofilm formation in vitro and in vivo . In addition, acetylcholine protected G. mellonella larvae from C. albicans infection mortality. The in vivo protection occurred through acetylcholine enhancing the function of hemocytes while at the same time inhibiting C. albicans biofilm formation. Furthermore, acetylcholine also inhibited inflammation-induced damage to internal organs. This is the first demonstration of a role for acetylcholine in protection against fungal infections, in addition to being the first report that this molecule can inhibit C. albicans biofilm formation. Therefore, acetylcholine has the capacity to modulate complex host-fungal interactions and plays a role in dictating the pathogenesis of fungal infections.

scholarly journals Candida albicans forms biofilms on the vaginal mucosa

Microbiology ◽  
2010 ◽  
Vol 156 (12) ◽  
pp. 3635-3644 ◽  
Author(s):  
M. M. Harriott ◽  
E. A. Lilly ◽  
T. E. Rodriguez ◽  
P. L. Fidel ◽  
M. C. Noverr
Keyword(s):  
Biofilm Formation ◽  
Ex Vivo ◽  
Microscopic Analysis ◽  
Vaginal Mucosa ◽  
First Time ◽  
Established Role ◽  
Type Strains

Current understanding of resistance and susceptibility to vulvovaginal candidiasis challenges existing paradigms of host defence against fungal infection. While abiotic biofilm formation has a clearly established role during systemic Candida infections, it is not known whether C. albicans forms biofilms on the vaginal mucosa and the possible role of biofilms in disease. In vivo and ex vivo murine vaginitis models were employed to examine biofilm formation by scanning electron and confocal microscopy. C. albicans strains included 3153A (lab strain), DAY185 (parental control strain), and mutants defective in morphogenesis and/or biofilm formation in vitro (efg1/efg1 and bcr1/bcr1). Both 3153A and DAY815 formed biofilms on the vaginal mucosa in vivo and ex vivo as indicated by high fungal burden and microscopic analysis demonstrating typical biofilm architecture and presence of extracellular matrix (ECM) co-localized with the presence of fungi. In contrast, efg1/efg1 and bcr1/bcr1 mutant strains exhibited weak or no biofilm formation/ECM production in both models compared to wild-type strains and complemented mutants despite comparable colonization levels. These data show for the first time that C. albicans forms biofilms in vivo on vaginal epithelium, and that in vivo biotic biofilm formation requires regulators of biofilm formation (BCR1) and morphogenesis (EFG1).

scholarly journals Characterization of Biofilm Formation and the Role of BCR1 in Clinical Isolates of Candida parapsilosis

2013 ◽  
Vol 13 (4) ◽  
pp. 438-451 ◽  
Author(s):  
Srisuda Pannanusorn ◽  
Bernardo Ramírez-Zavala ◽  
Heinrich Lünsdorf ◽  
Birgitta Agerberth ◽  
Joachim Morschhäuser ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Candida Parapsilosis ◽  
Clinical Isolates ◽  
Wild Type ◽  
Content Type ◽  
Initial Adhesion ◽  
High Level ◽  
Increased Susceptibility

ABSTRACT In Candida parapsilosis , biofilm formation is considered to be a major virulence factor. Previously, we determined the ability of 33 clinical isolates causing bloodstream infection to form biofilms and identified three distinct groups of biofilm-forming strains (negative, low, and high). Here, we establish two different biofilm structures among strains forming large amounts of biofilm in which strains with complex spider-like structures formed robust biofilms on different surface materials with increased resistance to fluconazole. Surprisingly, the transcription factor Bcr1, required for biofilm formation in Candida albicans and C. parapsilosis , has an essential role only in strains with low capacity for biofilm formation. Although BCR1 leads to the formation of more and longer pseudohyphae, it was not required for initial adhesion and formation of mature biofilms in strains with a high level of biofilm formation. Furthermore, an additional phenotype affected by BCR1 was the switch in colony morphology from rough to crepe, but only in strains forming high levels of biofilm. All bcr1 Δ/Δ mutants showed increased proteolytic activity and increased susceptibility to the antimicrobial peptides protamine and RP-1 compared to corresponding wild-type and complemented strains. Taken together, our results demonstrate that biofilm formation in clinical isolates of C. parapsilosis is both dependent and independent of BCR1 , but even in strains which showed a BCR1 -independent biofilm phenotype, BCR1 has alternative physiological functions.

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 Beyond the Wall: Exopolysaccharides in the Biofilm Lifestyle of Pathogenic and Beneficial Plant-Associated Pseudomonas

2021 ◽  
Vol 9 (2) ◽  
pp. 445
Author(s):  
Zaira Heredia-Ponce ◽  
Antonio de Vicente ◽  
Francisco M. Cazorla ◽  
José Antonio Gutiérrez-Barranquero
Keyword(s):  
Extracellular Matrix ◽  
Biofilm Formation ◽  
Clinical Importance ◽  
Ecological Significance ◽  
Human Pathogen ◽  
Metabolic Versatility ◽  
Polysaccharide Synthesis ◽  
Biofilm Architecture ◽  
Opportunistic Human Pathogen ◽  
Genetic Context

The formation of biofilms results from a multicellular mode of growth, in which bacteria remain enwrapped by an extracellular matrix of their own production. Many different bacteria form biofilms, but among the most studied species are those that belong to the Pseudomonas genus due to the metabolic versatility, ubiquity, and ecological significance of members of this group of microorganisms. Within the Pseudomonas genus, biofilm studies have mainly focused on the opportunistic human pathogen Pseudomonas aeruginosa due to its clinical importance. The extracellular matrix of P. aeruginosa is mainly composed of exopolysaccharides, which have been shown to be important for the biofilm architecture and pathogenic features of this bacterium. Notably, some of the exopolysaccharides recurrently used by P. aeruginosa during biofilm formation, such as the alginate and polysaccharide synthesis loci (Psl) polysaccharides, are also used by pathogenic and beneficial plant-associated Pseudomonas during their interaction with plants. Interestingly, their functions are multifaceted and seem to be highly dependent on the bacterial lifestyle and genetic context of production. This paper reviews the functions and significance of the exopolysaccharides produced by plant-associated Pseudomonas, particularly the alginate, Psl, and cellulose polysaccharides, focusing on their equivalents produced in P. aeruginosa within the context of pathogenic and beneficial interactions.

scholarly journals Na+/H+Antiport Is Essential for Yersinia pestis Virulence

2013 ◽  
Vol 81 (9) ◽  
pp. 3163-3172 ◽  
Author(s):  
Yusuke Minato ◽  
Amit Ghosh ◽  
Wyatt J. Faulkner ◽  
Erin J. Lind ◽  
Sara Schesser Bartra ◽  
...  
Keyword(s):  
Yersinia Pestis ◽  
Drug Target ◽  
Deletion Mutant ◽  
Ex Vivo ◽  
Ion Homeostasis ◽  
Content Type ◽  
Double Deletion ◽  
Derivative Strain

ABSTRACTNa+/H+antiporters are ubiquitous membrane proteins that play a central role in the ion homeostasis of cells. In this study, we examined the possible role of Na+/H+antiport inYersinia pestisvirulence and found thatY. pestisstrains lacking the major Na+/H+antiporters, NhaA and NhaB, are completely attenuated in anin vivomodel of plague. TheY. pestisderivative strain lacking thenhaAandnhaBgenes showed markedly decreased survival in blood and blood serumex vivo. Complementation of eithernhaAornhaBintransrestored the survival of theY. pestis nhaA nhaBdouble deletion mutant in blood. ThenhaA nhaBdouble deletion mutant also showed inhibited growth in an artificial serum medium, Opti-MEM, and a rich LB-based medium with Na+levels and pH values similar to those for blood. Taken together, these data strongly suggest that intact Na+/H+antiport is indispensable for the survival ofY. pestisin the bloodstreams of infected animals and thus might be regarded as a promising noncanonical drug target for infections caused byY. pestisand possibly for those caused by other blood-borne bacterial pathogens.

scholarly journals Role of Bordetella O Antigen in Respiratory Tract Infection

2003 ◽  
Vol 71 (1) ◽  
pp. 86-94 ◽  
Author(s):  
Valorie C. Burns ◽  
Elizabeth J. Pishko ◽  
Andrew Preston ◽  
Duncan J. Maskell ◽  
Eric T. Harvill
Keyword(s):  
Tract Infection ◽  
Respiratory Tract ◽  
Respiratory Tract Infection ◽  
Human Pathogen ◽  
O Antigen ◽  
Highly Sensitive ◽  
Major Surface

ABSTRACT Lipopolysaccharide (LPS), as the major surface molecule of gram-negative bacteria, interacts with the host in complex ways, both inducing and protecting against aspects of inflammatory and adaptive immunity. The membrane-distal repeated carbohydrate structure of LPS, the O antigen, can prevent antibody functions and may vary as a mechanism of immune evasion. Genes of the wbm locus are required for the assembly of O antigen on the animal pathogen Bordetella bronchiseptica and the human pathogen B. parapertussis. However, the important human pathogen B. pertussis lacks these genes and a number of in vitro and in vivo characteristics associated with O antigen in other organisms. To determine the specific functions of O antigen in these closely related Bordetella subspecies, we compared wbm deletion (Δwbm) mutants of B. bronchiseptica and B. parapertussis in a variety of assays relevant to natural respiratory tract infection. Complement was not activated or depleted by wild-type bordetellae expressing O antigen, but both Δwbm mutants activated complement and were highly sensitive to complement-mediated killing in vitro. Although the O-antigen structures appear to be substantially similar, the two mutants differed strikingly in their defects within the respiratory tract. The B. parapertussis Δwbm mutant was severely defective in colonization of the tracheas and lungs of mice, while the B. bronchiseptica Δwbm mutant showed almost no defect. While in vitro characteristics such as serum resistance may be attributable to O antigen directly, the role of O antigen during infection appears to be more complex, possibly involving factors differing among the closely related bordetellae or different interactions between each one and its host.

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.

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