scholarly journals Characterizing Pneumocystis in the Lungs of Bats: Understanding Pneumocystis Evolution and the Spread of Pneumocystis Organisms in Mammal Populations

2012 ◽  
Vol 78 (22) ◽  
pp. 8122-8136 ◽  
Author(s):  
Haroon Akbar ◽  
Claire Pinçon ◽  
Cecile-Marie Aliouat-Denis ◽  
Sandra Derouiche ◽  
Maria-Lucia Taylor ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Fungal Pathogens ◽  
Geographic Area ◽  
Heterogeneous Group ◽  
Ecological Niches ◽  
Behavioral Factors ◽  
Host Association ◽  
Content Type ◽  
Wide Range ◽  
Life Threatening

ABSTRACTBats belong to a wide variety of species and occupy diversified habitats, from cities to the countryside. Their different diets (i.e., nectarivore, frugivore, insectivore, hematophage) lead Chiroptera to colonize a range of ecological niches. These flying mammals exert an undisputable impact on both ecosystems and circulation of pathogens that they harbor.Pneumocystisspecies are recognized as major opportunistic fungal pathogens which cause life-threatening pneumonia in severely immunocompromised or weakened mammals.Pneumocystisconsists of a heterogeneous group of highly adapted host-specific fungal parasites that colonize a wide range of mammalian hosts. In the present study, 216 lungs of 19 bat species, sampled from diverse biotopes in the New and Old Worlds, were examined. Each bat species may be harboring a specificPneumocystisspecies. We report 32.9% ofPneumocystiscarriage in wild bats (41.9% in Microchiroptera). Ecological and behavioral factors (elevation, crowding, migration) seemed to influence thePneumocystiscarriage. This study suggests thatPneumocystis-host association may yield much information onPneumocystistransmission, phylogeny, and biology in mammals. Moreover, the link between genetic variability ofPneumocystisisolated from populations of the same bat species and their geographic area could be exploited in terms of phylogeography.

scholarly journals Pleiotropic Roles of the Msi1-Like Protein Msl1 in Cryptococcus neoformans

2012 ◽  
Vol 11 (12) ◽  
pp. 1482-1495 ◽  
Author(s):  
Dong-Hoon Yang ◽  
Shinae Maeng ◽  
Anna K. Strain ◽  
Anna Floyd ◽  
Kirsten Nielsen ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Stress Responses ◽  
Fungal Pathogens ◽  
Independent Manner ◽  
Content Type ◽  
Antifungal Drug Resistance ◽  
Human Fungal Pathogen ◽  
Assembly Factor ◽  
Life Threatening ◽  
Stress Related Genes

ABSTRACT Msi1-like (MSIL) proteins contain WD40 motifs and have a pleiotropic cellular function as negative regulators of the Ras/cyclic AMP (cAMP) pathway and components of chromatin assembly factor 1 (CAF-1), yet they have not been studied in fungal pathogens. Here we identified and characterized an MSIL protein, Msl1, in Cryptococcus neoformans , which causes life-threatening meningoencephalitis in humans. Notably, Msl1 plays pleiotropic roles in C. neoformans in both cAMP-dependent and -independent manners largely independent of Ras. Msl1 negatively controls antioxidant melanin production and sexual differentiation, and this was repressed by the inhibition of the cAMP-signaling pathway. In contrast, Msl1 controls thermotolerance, diverse stress responses, and antifungal drug resistance in a Ras/cAMP-independent manner. Cac2, which is the second CAF-1 component, appears to play both redundant and distinct functions compared to the functions of Msl1. Msl1 is required for the full virulence of C. neoformans . Transcriptome analysis identified a group of Msl1-regulated genes, which include stress-related genes such as HSP12 and HSP78 . In conclusion, this study demonstrates pleiotropic roles of Msl1 in the human fungal pathogen C. neoformans , providing insight into a potential novel antifungal therapeutic target.

scholarly journals Plasma Membrane MCC/Eisosome Domains Promote Stress Resistance in Fungi

2020 ◽  
Vol 84 (4) ◽  
Author(s):  
Carla E. Lanze ◽  
Rafael M. Gandra ◽  
Jenna E. Foderaro ◽  
Kara A. Swenson ◽  
Lois M. Douglas ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Fungal Pathogens ◽  
Composition Studies ◽  
Copper Toxicity ◽  
Fungal Species ◽  
Content Type ◽  
Functional Roles ◽  
Wide Range ◽  
Membrane Compartment ◽  
Plasma Membrane Domain

SUMMARY There is growing appreciation that the plasma membrane orchestrates a diverse array of functions by segregating different activities into specialized domains that vary in size, stability, and composition. Studies with the budding yeast Saccharomyces cerevisiae have identified a novel type of plasma membrane domain known as the MCC (membrane compartment of Can1)/eisosomes that correspond to stable furrows in the plasma membrane. MCC/eisosomes maintain proteins at the cell surface, such as nutrient transporters like the Can1 arginine symporter, by protecting them from endocytosis and degradation. Recent studies from several fungal species are now revealing new functional roles for MCC/eisosomes that enable cells to respond to a wide range of stressors, including changes in membrane tension, nutrition, cell wall integrity, oxidation, and copper toxicity. The different MCC/eisosome functions are often intertwined through the roles of these domains in lipid homeostasis, which is important for proper plasma membrane architecture and cell signaling. Therefore, this review will emphasize the emerging models that explain how MCC/eisosomes act as hubs to coordinate cellular responses to stress. The importance of MCC/eisosomes is underscored by their roles in virulence for fungal pathogens of plants, animals, and humans, which also highlights the potential of these domains to act as novel therapeutic targets.

scholarly journals Multiplex CRISPRi System Enables the Study of Stage-Specific Biofilm Genetic Requirements in Enterococcus faecalis

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Irina Afonina ◽  
June Ong ◽  
Jerome Chua ◽  
Timothy Lu ◽  
Kimberly A. Kline
Keyword(s):  
Enterococcus Faecalis ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Expression System ◽  
Multidrug Resistant ◽  
Essential Genes ◽  
Host Bacterium ◽  
Content Type ◽  
Wide Range ◽  
Life Threatening

ABSTRACT Enterococcus faecalis is an opportunistic pathogen, which can cause multidrug-resistant life-threatening infections. Gaining a complete understanding of enterococcal pathogenesis is a crucial step in identifying a strategy to effectively treat enterococcal infections. However, bacterial pathogenesis is a complex process often involving a combination of genes and multilevel regulation. Compared to established knockout methodologies, CRISPR interference (CRISPRi) approaches enable the rapid and efficient silencing of genes to interrogate gene products and pathways involved in pathogenesis. As opposed to traditional gene inactivation approaches, CRISPRi can also be quickly repurposed for multiplexing or used to study essential genes. Here, we have developed a novel dual-vector nisin-inducible CRISPRi system in E. faecalis that can efficiently silence via both nontemplate and template strand targeting. Since the nisin-controlled gene expression system is functional in various Gram-positive bacteria, the developed CRISPRi tool can be extended to other genera. This system can be applied to study essential genes, genes involved in antimicrobial resistance, and genes involved in biofilm formation and persistence. The system is robust and can be scaled up for high-throughput screens or combinatorial targeting. This tool substantially enhances our ability to study enterococcal biology and pathogenesis, host-bacterium interactions, and interspecies communication. IMPORTANCE Enterococcus faecalis causes multidrug-resistant life-threatening infections and is often coisolated with other pathogenic bacteria from polymicrobial biofilm-associated infections. Genetic tools to dissect complex interactions in mixed microbial communities are largely limited to transposon mutagenesis and traditional time- and labor-intensive allelic-exchange methods. Built upon streptococcal dCas9, we developed an easily modifiable, inducible CRISPRi system for E. faecalis that can efficiently silence single and multiple genes. This system can silence genes involved in biofilm formation and antibiotic resistance and can be used to interrogate gene essentiality. Uniquely, this tool is optimized to study genes important for biofilm initiation, maturation, and maintenance and can be used to perturb preformed biofilms. This system will be valuable to rapidly and efficiently investigate a wide range of aspects of complex enterococcal biology.

scholarly journals Dissecting Disease-Suppressive Rhizosphere Microbiomes by Functional Amplicon Sequencing and 10× Metagenomics

mSystems ◽  
2021 ◽  
Author(s):  
Vittorio Tracanna ◽  
Adam Ossowicki ◽  
Marloes L. C. Petrus ◽  
Sam Overduin ◽  
Barbara R. Terlouw ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Pathogenic Fungi ◽  
Amplicon Sequencing ◽  
Plant Pathogenic Fungi ◽  
Content Type ◽  
Major Threat ◽  
Wide Range

Soil-borne plant-pathogenic fungi continue to be a major threat to agriculture and horticulture. The genus Fusarium in particular is one of the most devastating groups of soilborne fungal pathogens for a wide range of crops.

scholarly journals New CRISPR Mutagenesis Strategies Reveal Variation in Repair Mechanisms among Fungi

mSphere ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Valmik K. Vyas ◽  
G. Guy Bushkin ◽  
Douglas A. Bernstein ◽  
Matthew A. Getz ◽  
Magdalena Sewastianik ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Genome Engineering ◽  
High Efficiency ◽  
Selection Marker ◽  
Important Species ◽  
Content Type ◽  
Guide Rna ◽  
Wide Range ◽  
Repair Mechanisms ◽  
The Creation

ABSTRACT We have created new vectors for clustered regularly interspaced short palindromic repeat (CRISPR) mutagenesis in Candida albicans , Saccharomyces cerevisiae , Candida glabrata , and Naumovozyma castellii . These new vectors permit a comparison of the requirements for CRISPR mutagenesis in each of these species and reveal different dependencies for repair of the Cas9 double-stranded break. Both C. albicans and S. cerevisiae rely heavily on homology-directed repair, whereas C. glabrata and N. castellii use both homology-directed and nonhomologous end-joining pathways. The high efficiency of these vectors permits the creation of unmarked deletions in each of these species and the recycling of the dominant selection marker for serial mutagenesis in prototrophs. A further refinement, represented by the "Unified" Solo vectors, incorporates Cas9, guide RNA, and repair template into a single vector, thus enabling the creation of vector libraries for pooled screens. To facilitate the design of such libraries, we have identified guide sequences for each of these species with updated guide selection algorithms. IMPORTANCE CRISPR-mediated genome engineering technologies have revolutionized genetic studies in a wide range of organisms. Here we describe new vectors and guide sequences for CRISPR mutagenesis in the important human fungal pathogens C. albicans and C. glabrata , as well as in the related yeasts S. cerevisiae and N. castellii . The design of these vectors enables efficient serial mutagenesis in each of these species by leaving few, if any, exogenous sequences in the genome. In addition, we describe strategies for the creation of unmarked deletions in each of these species and vector designs that permit the creation of vector libraries for pooled screens. These tools and strategies promise to advance genetic engineering of these medically and industrially important species.

scholarly journals From Q Fever to Coxiella burnetii Infection: a Paradigm Change

2016 ◽  
Vol 30 (1) ◽  
pp. 115-190 ◽  
Author(s):  
Carole Eldin ◽  
Cléa Mélenotte ◽  
Oleg Mediannikov ◽  
Eric Ghigo ◽  
Matthieu Million ◽  
...  
Keyword(s):  
Coxiella Burnetii ◽  
Q Fever ◽  
Axenic Culture ◽  
Geographic Area ◽  
Human Infection ◽  
Comparative Genomic ◽  
Paradigm Change ◽  
Major Step ◽  
Content Type ◽  
Wide Range

SUMMARY Coxiella burnetii is the agent of Q fever, or “query fever,” a zoonosis first described in Australia in 1937. Since this first description, knowledge about this pathogen and its associated infections has increased dramatically. We review here all the progress made over the last 20 years on this topic. C. burnetii is classically a strict intracellular, Gram-negative bacterium. However, a major step in the characterization of this pathogen was achieved by the establishment of its axenic culture. C. burnetii infects a wide range of animals, from arthropods to humans. The genetic determinants of virulence are now better known, thanks to the achievement of determining the genome sequences of several strains of this species and comparative genomic analyses. Q fever can be found worldwide, but the epidemiological features of this disease vary according to the geographic area considered, including situations where it is endemic or hyperendemic, and the occurrence of large epidemic outbreaks. In recent years, a major breakthrough in the understanding of the natural history of human infection with C. burnetii was the breaking of the old dichotomy between “acute” and “chronic” Q fever. The clinical presentation of C. burnetii infection depends on both the virulence of the infecting C. burnetii strain and specific risks factors in the infected patient. Moreover, no persistent infection can exist without a focus of infection. This paradigm change should allow better diagnosis and management of primary infection and long-term complications in patients with C. burnetii infection.

scholarly journals Immobilization of Antibacterial Dihydropyrrol-2-ones on Functional Polymer Supports To Prevent Bacterial InfectionsIn Vivo

2011 ◽  
Vol 56 (2) ◽  
pp. 1138-1141 ◽  
Author(s):  
Kitty Ka Kit Ho ◽  
Nerida Cole ◽  
Renxun Chen ◽  
Mark D. P. Willcox ◽  
Scott A. Rice ◽  
...  
Keyword(s):  
Staphylococcal Infection ◽  
Infection Model ◽  
Dependent Manner ◽  
Pathogenic Potential ◽  
Antibiotic Resistant ◽  
Content Type ◽  
Polymer Supports ◽  
Wide Range ◽  
Life Threatening

ABSTRACTAntibiotic-resistantStaphylococcus aureusis of great concern, as it causes a wide range of life-threatening infections. The current study demonstrates that dihydropyrrolone (DHP)-coated polyacrylamide substrates are effective in reducing the number of culturable clinical isolates ofS. aureusin vitroin a dose-dependent manner and are able to reduce the pathogenic potential of staphylococcal infection in a subcutaneous infection model. Covalently bound DHPs therefore show great potential for use as an antimicrobial strategy in device-related applications.

scholarly journals LysR-Type Transcriptional Regulator MetR Controls Prodigiosin Production, Methionine Biosynthesis, Cell Motility, H2O2 Tolerance, Heat Tolerance, and Exopolysaccharide Synthesis in Serratia marcescens

2019 ◽  
Vol 86 (4) ◽  
Author(s):  
Xuewei Pan ◽  
Changhao Sun ◽  
Mi Tang ◽  
Jiajia You ◽  
Tolbert Osire ◽  
...  
Keyword(s):  
Cell Motility ◽  
Serratia Marcescens ◽  
Heat Tolerance ◽  
Biofilm Formation ◽  
Regulatory Mechanisms ◽  
Ecological Niches ◽  
Methionine Biosynthesis ◽  
Mobility Shift ◽  
Content Type ◽  
Wide Range

ABSTRACT Prodigiosin, a secondary metabolite produced by Serratia marcescens, has attracted attention due to its immunosuppressive, antimicrobial, and anticancer properties. However, information on the regulatory mechanism behind prodigiosin biosynthesis in S. marcescens remains limited. In this work, a prodigiosin-hyperproducing strain with the BVG90_22495 gene disrupted (ZK66) was selected from a collection of Tn5G transposon insertion mutants. Using real-time quantitative PCR (RT-qPCR) analysis, β-galactosidase assays, transcriptomics analysis, and electrophoretic mobility shift assays (EMSAs), the LysR-type regulator MetR encoded by the BVG90_22495 gene was found to affect prodigiosin synthesis, and this correlated with MetR directly binding to the promoter region of the prodigiosin-synthesis positive regulator PigP and hence negatively regulated the expression of the prodigiosin-associated pig operon. More analyses revealed that MetR regulated some other important cellular processes, including methionine biosynthesis, cell motility, H2O2 tolerance, heat tolerance, exopolysaccharide synthesis, and biofilm formation in S. marcescens. Although MetR protein is highly conserved in many bacteria, we report here on the LysR-type regulator MetR exhibiting novel roles in negatively regulating prodigiosin synthesis and positively regulating heat tolerance, exopolysaccharide synthesis, and biofilm formation. IMPORTANCE Serratia marcescens, a Gram-negative bacterium, is found in a wide range of ecological niches and can produce several secondary metabolites, including prodigiosin, althiomycin, and serratamolide. Among them, prodigiosin shows diverse functions as an immunosuppressant, antimicrobial, and anticancer agent. However, the regulatory mechanisms behind prodigiosin synthesis in S. marcescens are not completely understood. Here, we adapted a transposon mutant library to identify the genes related to prodigiosin synthesis, and the BVG90_22495 gene encoding the LysR-type regulator MetR was found to negatively regulate prodigiosin synthesis. The molecular mechanism of the metR mutant hyperproducing prodigiosin was investigated. Additionally, we provided evidence supporting new roles for MetR in regulating methionine biosynthesis, cell motility, heat tolerance, H2O2 tolerance, and exopolysaccharide synthesis in S. marcescens. Collectively, this work provides novel insight into regulatory mechanisms of prodigiosin synthesis and uncovers novel roles for the highly conserved MetR protein in regulating prodigiosin synthesis, heat tolerance, exopolysaccharide (EPS) synthesis, and biofilm formation.

Characterization of the shopping preferences and needs of low-income consumers living in food deserts

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Samantha Mogil ◽  
Evanah Hill ◽  
Jennifer Quinlan
Keyword(s):  
Low Income ◽  
Food Access ◽  
Fresh Produce ◽  
Food Deserts ◽  
Geographic Area ◽  
Content Type ◽  
Perishable Goods ◽  
Wide Range ◽  
Shopping Experience ◽  
Low Income Consumers

PurposeLack of access to supermarkets and fresh produce continues to be a problem for low income consumers in many countries. The purpose of this research was to identify the shopping preferences and needs of such consumers in the Eastern U.S. Additionally, the research sought to determine the interest and preferences of low income consumers in a mobile grocery intervention which would provide neighborhoods with a consistent, convenient shopping experience.Design/methodology/approachA mixed methods approach included conducting focus groups in low-income neighborhoods in Philadelphia, Pennsylvania, U.S.A. and a quantitative survey (n = 202) administered via Survey Monkey to low-income consumers. Thematic analysis was conducted on focus group data and surveys were administered and analyzed to assess applicability of themes identified to consumers over a larger geographic area.FindingsResults indicated that consumers in food desert neighborhoods reported an interest in purchasing a wide range of food staples, household goods, and personal items from any shopping intervention. Participants indicated a need for a more convenient overall shopping experience for a range of foods and goods in addition to fresh food choices. Findings indicate that mobile interventions to increase food access may benefit from expanding products available through the intervention beyond fresh produce and perishable goods.Originality/valueThis research explored purchasing preferences with low income consumers living in food deserts. It identifies products and goods they would prefer to see in an intervention to increase food access and is unique in that it explores the wants and preferences of consumers living in food deserts.

scholarly journals Heat-Stable Antifungal Factor (HSAF) Biosynthesis inLysobacter enzymogenesIs Controlled by the Interplay of Two Transcription Factors and a Diffusible Molecule

2017 ◽  
Vol 84 (3) ◽  
Author(s):  
Zhenhe Su ◽  
Sen Han ◽  
Zheng Qing Fu ◽  
Guoliang Qian ◽  
Fengquan Liu
Keyword(s):  
Fungal Pathogens ◽  
Bacterial Species ◽  
Regulatory Function ◽  
Regulatory Pathway ◽  
Content Type ◽  
Heat Stable ◽  
Wide Range ◽  
Diffusible Factor ◽  
Regulatory Effects

ABSTRACTLysobacter enzymogenesis a Gram-negative, environmentally ubiquitous bacterium that produces a secondary metabolite, called heat-stable antifungal factor (HSAF), as an antifungal factor against plant and animal fungal pathogens. 4-Hydroxybenzoic acid (4-HBA) is a newly identified diffusible factor that regulates HSAF synthesis viaL. enzymogenesLysR (LysRLe), an LysR-type transcription factor (TF). Here, to identify additional TFs within the 4-HBA regulatory pathway that control HSAF production, we reanalyzed the LenB2-based transcriptomic data, in which LenB2 is the enzyme responsible for 4-HBA production. This survey led to identification of three TFs (Le4806, Le4969, and Le3904). Of them, LarR (Le4806), a member of the MarR family proteins, was identified as a new TF that participated in the 4-HBA-dependent regulation of HSAF production. Our data show the following: (i) that LarR is a downstream component of the 4-HBA regulatory pathway controlling the HSAF level, while LysRLeis the receptor of 4-HBA; (ii) that 4-HBA and LysRLehave opposite regulatory effects onlarRtranscription wherebylarRtranscript is negatively modulated by 4-HBA while LysRLe, in contrast, exerts positive transcriptional regulation by directly binding to thelarRpromoter without being affected by 4-HBAin vitro; (iii) that LarR, similar to LysRLe, can bind to the promoter of the HSAF biosynthetic gene operon, leading to positive regulation of HSAF production; and (iv) that LarR and LysRLecannot interact and instead control HSAF biosynthesis independently. These results outline a previously uncharacterized mechanism by which biosynthesis of the antibiotic HSAF inL. enzymogenesis modulated by the interplay of 4-HBA, a diffusible molecule, and two different TFs.IMPORTANCEBacteria use diverse chemical signaling molecules to regulate a wide range of physiological and cellular processes. 4-HBA is an “old” chemical molecule that is produced by diverse bacterial species, but its regulatory function and working mechanism remain largely unknown. We previously found that 4-HBA inL. enzymogenescould serve as a diffusible factor regulating HSAF synthesis via LysRLe. Here, we further identified LarR, an MarR family protein, as a second TF that participates in the 4-HBA-dependent regulation of HSAF biosynthesis. Our results dissected how LarR acts as a protein linker to connect 4-HBA and HSAF synthesis, whereby LarR also has cross talk with LysRLe. Thus, our findings not only provide fundamental insight regarding how a diffusible molecule (4-HBA) adopts two different types of TFs for coordinating HSAF biosynthesis but also show the use of applied microbiology to increase the yield of the antibiotic HSAF by modification of the 4-HBA regulatory pathway inL. enzymogenes.

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