scholarly journals Distinct Roles of Candida albicans-Specific Genes in Host-Pathogen Interactions

2014 ◽  
Vol 13 (8) ◽  
pp. 977-989 ◽  
Author(s):  
Duncan Wilson ◽  
François L. Mayer ◽  
Pedro Miramón ◽  
Francesco Citiulo ◽  
Silvia Slesiona ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Host Cells ◽  
Transcriptional Analysis ◽  
Phenotypic Characterization ◽  
Host Pathogen Interactions ◽  
Pathogenic Potential ◽  
Hyphal Branching ◽  
Content Type ◽  
Host Pathogen

ABSTRACTHuman fungal pathogens are distributed throughout their kingdom, suggesting that pathogenic potential evolved independently.Candida albicansis the most virulent member of the CUG clade of yeasts and a common cause of both superficial and invasive infections. We therefore hypothesized thatC. albicanspossesses distinct pathogenicity mechanisms.In silicogenome subtraction and comparative transcriptional analysis identified a total of 65C.albicans-specificgenes (ASGs) expressed during infection. Phenotypic characterization of six ASG-null mutants demonstrated that these genes are dispensable forin vitrogrowth but play defined roles in host-pathogen interactions. Based on these analyses, we investigated two ASGs in greater detail. An orf19.6688Δ mutant was found to be fully virulent in a mouse model of disseminated candidiasis and to induce higher levels of the proinflammatory cytokine interleukin-1β (IL-1β) following incubation with murine macrophages. Apga16Δ mutant, on the other hand, exhibited attenuated virulence. Moreover, we provide evidence that secondary filamentation events (multiple hyphae emerging from a mother cell and hyphal branching) contribute to pathogenicity:PGA16deletion did not influence primary hypha formation or extension following contact with epithelial cells; however, multiple hyphae and hyphal branching were strongly reduced. Significantly, these hyphae failed to damage host cells as effectively as the multiple hypha structures formed by wild-typeC. albicanscells. Together, our data show that species-specific genes of a eukaryotic pathogen can play important roles in pathogenicity.

scholarly journals Clinical Candida albicans Vaginal Isolates and a Laboratory Strain Show Divergent Behaviors during Macrophage Interactions

mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Franziska Gerwien ◽  
Christine Dunker ◽  
Philipp Brandt ◽  
Enrico Garbe ◽  
Ilse D. Jacobsen ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Fungal Infections ◽  
Laboratory Strain ◽  
Infection Process ◽  
Vulvovaginal Candidiasis ◽  
Host Immune System ◽  
Host Pathogen Interactions ◽  
Content Type ◽  
Host Pathogen

ABSTRACT Typically, established lab strains are widely used to study host-pathogen interactions. However, to better reflect the infection process, the experimental use of clinical isolates has come more into focus. Here, we analyzed the interaction of multiple vaginal isolates of the opportunistic fungal pathogen Candida albicans, the most common cause of vulvovaginal candidiasis in women, with key players of the host immune system: macrophages. We tested several strains isolated from asymptomatic or symptomatic women with acute and recurrent infections. While all clinical strains showed a response similar to the commonly used lab strain SC5314 in various in vitro assays, they displayed remarkable differences during interaction with macrophages. This coincided with significantly reduced β-glucan exposure on the cell surface, which appeared to be a shared property among the tested vaginal strains for yeast extract/peptone/dextrose-grown cells, which is partly lost when the isolates faced vaginal niche-like nutrient conditions. However, macrophage damage, survival of phagocytosis, and filamentation capacities were highly strain-specific. These results highlight the high heterogeneity of C. albicans strains in host-pathogen interactions, which have to be taken into account to bridge the gap between laboratory-gained data and disease-related outcomes in an actual patient. IMPORTANCE Vulvovaginal candidiasis is one of the most common fungal infections in humans with Candida albicans as the major causative agent. This study is the first to compare clinical vaginal isolates of defined patient groups in their interaction with macrophages, highlighting the vastly different outcomes in comparison to a laboratory strain using commonly applied virulence-determining assays.

scholarly journals Novel Effective Bacillus cereus Group Species “Bacillus clarus” Is Represented by Antibiotic-Producing Strain ATCC 21929 Isolated from Soil

mSphere ◽  
2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Marysabel Méndez Acevedo ◽  
Laura M. Carroll ◽  
Manjari Mukherjee ◽  
Emma Mills ◽  
Lingzi Xiaoli ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Hela Cells ◽  
Species Complex ◽  
Taxonomic Classification ◽  
Phenotypic Characterization ◽  
Pathogenic Potential ◽  
Cytotoxic Effects ◽  
Content Type ◽  
Group Species

ABSTRACT Gram-positive, spore-forming members of the Bacillus cereus group species complex are widespread in natural environments and display various degrees of pathogenicity. Recently, B. cereus group strain Bacillus mycoides Flugge ATCC 21929 was found to represent a novel lineage within the species complex, sharing a relatively low degree of genomic similarity with all B. cereus group genomes (average nucleotide identity [ANI] < 88). ATCC 21929 has been previously associated with the production of a patented antibiotic, antibiotic 60-6 (i.e., cerexin A); however, the virulence potential and growth characteristics of this lineage have never been assessed. Here, we provide an extensive genomic and phenotypic characterization of ATCC 21929, and we assess its pathogenic potential in vitro. ATCC 21929 most closely resembles Bacillus paramycoides NH24A2T (ANI and in silico DNA-DNA hybridization values of 86.70 and 34.10%, respectively). Phenotypically, ATCC 21929 does not possess cytochrome c oxidase activity and is able to grow at a range of temperatures between 15 and 43°C and a range of pH between 6 and 9. At 32°C, ATCC 21929 shows weak production of diarrheal enterotoxin hemolysin BL (Hbl) but no production of nonhemolytic enterotoxin (Nhe); at 37°C, neither Hbl nor Nhe is produced. Additionally, at 37°C, ATCC 21929 does not exhibit cytotoxic effects toward HeLa cells. With regard to fatty acid composition, ATCC 21929 has iso-C17:0 present in highest abundance. Based on the characterization provided here, ATCC 21929T (= PS00077AT = PS00077BT = PSU-0922T = BHPT) represents a novel effective B. cereus group species, which we propose as effective species “Bacillus clarus.” IMPORTANCE The B. cereus group comprises numerous closely related lineages with various degrees of pathogenic potential and industrial relevance. Species-level taxonomic classification of B. cereus group strains is important for risk evaluation and communication but remains challenging. Biochemical and phenotypic assays are often used to assign B. cereus group strains to species but are insufficient for accurate taxonomic classification on a genomic scale. Here, we show that antibiotic-producing ATCC 21929 represents a novel lineage within the B. cereus group that, by all metrics used to delineate prokaryotic species, exemplifies a novel effective species. Furthermore, we show that ATCC 21929 is incapable of producing enterotoxins Hbl and Nhe or exhibiting cytotoxic effects on HeLa cells at human body temperature in vitro. These results provide greater insight into the genomic and phenotypic diversity of the B. cereus group and may be leveraged to inform future public health and food safety efforts.

scholarly journals Peptidylarginine Deiminase inhibition abolishes the production of large extracellular vesicles fromGiardia intestinalis, affecting host-pathogen interactions by hindering adhesion to host cells

2019 ◽  
Author(s):  
Bruno Gavinho ◽  
Izadora Volpato Rossi ◽  
Ingrid Evans-Osses ◽  
Sigrun Lange ◽  
Marcel Ivan Ramirez
Keyword(s):  
Extracellular Vesicles ◽  
Mammalian Cells ◽  
Deep Understanding ◽  
Arginine Deiminase ◽  
Host Cells ◽  
Peptidylarginine Deiminase ◽  
Host Pathogen Interactions ◽  
Host Pathogen ◽  
Pad Inhibitor

AbstractGiardia intestinalisis an anaerobic protozoan that is an important etiologic agent of inflammation-driven diarrhea worldwide. Although self-limiting, a deep understanding of the factors involved in the pathogenicity that produces the disruption of the intestinal barrier remains unknown. There is evidence that under diverse conditions, the parasite is capable of shedding extracellular vesicles (EVs) which could modulate the physiopathology of giardiasis. Here we describe new insights ofG. intestinalisEV production, revealing its capacity to shed two different enriched EV populations (large and small extracellular vesicles) and identified a relevant adhesion function associated only with the larger population. Our work also aimed at assessing the influences of two recently identified inhibitors of EV release in mammalian cells, namely peptidylarginine deiminase (PAD) inhibitor and cannabidiol (CBD), on EV release fromGiardiaand their putative effects on host-pathogen interactions. PAD-inhibitor Cl-amidine and CBD were both able to effectively reduce EV shedding, the PAD-inhibitor specifically affecting the release of large extracellular vesicles and interfering within vitrohost-pathogen interactions. The strong efficacy of the PAD-inhibitor onGiardiaEV release indicates a phylogenetically conserved pathway of PAD-mediated EV release, most likely affecting theGiardiaarginine deiminase (GiADI) homolog of mammalian PADs. While there is still much to learn aboutG. intestinalisinteraction with its host, our results suggest that large and small EVs may be differently involved in protozoa communication, and that EV-inhibitor treatment may be a novel strategy for recurrent giardiasis treatment.

scholarly journals Sustained Nitric Oxide-Releasing Nanoparticles Induce Cell Death in Candida albicans Yeast and Hyphal Cells, Preventing Biofilm FormationIn Vitroand in a Rodent Central Venous Catheter Model

2016 ◽  
Vol 60 (4) ◽  
pp. 2185-2194 ◽  
Author(s):  
Mohammed S. Ahmadi ◽  
Hiu Ham Lee ◽  
David A. Sanchez ◽  
Adam J. Friedman ◽  
Moses T. Tar ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Candida Albicans ◽  
Flow Cytometric Analysis ◽  
Extracellular Polysaccharide ◽  
Host Cells ◽  
Yeast Cells ◽  
Central Venous ◽  
Content Type ◽  
Biofilm Development

ABSTRACTCandida albicansis a leading nosocomial pathogen. Today, candidal biofilms are a significant cause of catheter infections, and such infections are becoming increasingly responsible for the failure of medical-implanted devices.C. albicansforms biofilms in which fungal cells are encased in an autoproduced extracellular polysaccharide matrix. Consequently, the enclosed fungi are protected from antimicrobial agents and host cells, providing a unique niche conducive to robust microbial growth and a harbor for recurring infections. Here we demonstrate that a recently developed platform comprised of nanoparticles that release therapeutic levels of nitric oxide (NO-np) inhibits candidal biofilm formation, destroys the extracellular polysaccharide matrices of mature fungal biofilms, and hinders biofilm development on surface biomaterials such as the lumen of catheters. We found NO-np to decrease both the metabolic activity of biofilms and the cell viability ofC. albicansin vitroandin vivo. Furthermore, flow cytometric analysis found NO-np to induce apoptosis in biofilm yeast cellsin vitro. Moreover, NO-np behave synergistically when used in combination with established antifungal drug therapies. Here we propose NO-np as a novel treatment modality, especially in combination with standard antifungals, for the prevention and/or remediation of fungal biofilms on central venous catheters and other medical devices.

scholarly journals MARTX Toxin-Stimulated Interplay between Human Cells and Vibrio vulnificus

mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Byoung Sik Kim ◽  
Jong-Hwan Kim ◽  
Sanghyeon Choi ◽  
Shinhye Park ◽  
Eun-Young Lee ◽  
...  
Keyword(s):  
Immune Responses ◽  
Immune Cells ◽  
Vibrio Vulnificus ◽  
Expression Profiles ◽  
Host Cells ◽  
Iron Limitation ◽  
Host Pathogen Interactions ◽  
Content Type ◽  
Host Pathogen ◽  
Ht 29

ABSTRACT To understand toxin-stimulated host-pathogen interactions, we performed dual-transcriptome sequencing experiments using human epithelial (HT-29) and differentiated THP-1 (dTHP-1) immune cells infected with the sepsis-causing pathogen Vibrio vulnificus (either the wild-type [WT] pathogen or a multifunctional-autoprocessing repeats-in-toxin [MARTX] toxin-deficient strain). Gene set enrichment analyses revealed MARTX toxin-dependent responses, including negative regulation of extracellular related kinase 1 (ERK1) and ERK2 (ERK1/2) signaling and cell cycle regulation in HT-29 and dTHP-1 cells, respectively. Further analysis of the expression of immune-related genes suggested that the MARTX toxin dampens immune responses in gut epithelial cells but accelerates inflammation and nuclear factor κB (NF-κB) signaling in immune cells. With respect to the pathogen, siderophore biosynthesis genes were significantly more highly expressed in WT V. vulnificus than in the MARTX toxin-deficient mutant upon infection of dTHP-1 cells. Consistent with these results, iron homeostasis genes that limit iron levels for invading pathogens were overexpressed in WT V. vulnificus-infected dTHP-1 cells. Taken together, these results suggest that MARTX toxin regulates host inflammatory responses during V. vulnificus infection while also countering host defense mechanisms such as iron limitation. IMPORTANCE V. vulnificus is an opportunistic human pathogen that can cause life-threatening sepsis in immunocompromised patients via seafood poisoning or wound infection. Among the toxic substances produced by this pathogen, the MARTX toxin greatly contributes to disease progression by promoting the dysfunction and death of host cells, which allows the bacteria to disseminate and colonize the host. In response to this, host cells mount a counterattack against the invaders by upregulating various defense genes. In this study, the gene expression profiles of both host cells and V. vulnificus were analyzed by RNA sequencing to gain a comprehensive understanding of host-pathogen interactions. Our results suggest that V. vulnificus uses the MARTX toxin to subvert host cell immune responses as well as to oppose host counterattacks such as iron limitation.

scholarly journals Isolation Site Influences Virulence Phenotype of Serotype 14 Streptococcus pneumoniae Strains Belonging to Multilocus Sequence Type 15

2015 ◽  
Vol 83 (12) ◽  
pp. 4781-4790 ◽  
Author(s):  
Zarina Amin ◽  
Richard M. Harvey ◽  
Hui Wang ◽  
Catherine E. Hughes ◽  
Adrienne W. Paton ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Immune Responses ◽  
Sequence Type ◽  
Transcriptional Analysis ◽  
Innate Immune Responses ◽  
Pathogenic Potential ◽  
Content Type ◽  
Niche Adaptation

Streptococcus pneumoniaeis a diverse species causing invasive as well as localized infections that result in massive global morbidity and mortality. Strains vary markedly in pathogenic potential, but the molecular basis is obscured by the diversity and plasticity of the pneumococcal genome. We have previously reported thatS. pneumoniaeserotype 3 isolates belonging to the same multilocus sequence type (MLST) differed markedly inin vitroandin vivophenotypes, in accordance with the clinical site of isolation, suggesting stable niche adaptation within a clonal lineage. In the present study, we have extended our analysis to serotype 14 clinical isolates from cases of sepsis or otitis media that belong to the same MLST (ST15). In a murine intranasal challenge model, five ST15 isolates (three from blood and two from ears) colonized the nasopharynx to similar extents. However, blood and ear isolates exhibited significant differences in bacterial loads in other host niches (lungs, ear, and brain) at both 24 and 72 h postchallenge. In spite of these differences, blood and ear isolates were present in the lungs at similar levels at 6 h postchallenge, suggesting that early immune responses may underpin the distinct virulence phenotypes. Transcriptional analysis of lung tissue from mice infected for 6 h with blood isolates versus ear isolates revealed 8 differentially expressed genes. Two of these were exclusively expressed in response to infection with the ear isolate. These results suggest a link between the differential capacities to elicit early innate immune responses and the distinct virulence phenotypes of clonally relatedS. pneumoniaestrains.

scholarly journals Concurrent Host-Pathogen Transcriptional Responses in aClostridium perfringensMurine Myonecrosis Infection

mBio ◽  
2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Lee-Yean Low ◽  
Paul F. Harrison ◽  
Jodee Gould ◽  
David R. Powell ◽  
Jocelyn M. Choo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Clostridium Perfringens ◽  
Virulence Genes ◽  
Host Cells ◽  
Transcriptional Analysis ◽  
Host Pathogen Interactions ◽  
Transcriptional Responses ◽  
Clostridial Myonecrosis ◽  
Muscle Tissues ◽  
Host Pathogen

ABSTRACTTo obtain an insight into host-pathogen interactions in clostridial myonecrosis, we carried out comparative transcriptome analysis of both the bacterium and the host in a murineClostridium perfringensinfection model, which is the first time that such an investigation has been conducted. Analysis of the host transcriptome from infected muscle tissues indicated that many genes were upregulated compared to the results seen with mock-infected mice. These genes were enriched for host defense pathways, including Toll-like receptor (TLR) and Nod-like receptor (NLR) signaling components. Real-time PCR confirmed that host TLR2 and NLRP3 inflammasome genes were induced in response toC. perfringensinfection. Comparison of the transcriptome ofC. perfringenscells from the infected tissues with that from broth cultures showed that host selective pressure induced a global change inC. perfringensgene expression. A total of 33% (923) ofC. perfringensgenes were differentially regulated, including 10 potential virulence genes that were upregulated relative to their expressionin vitro. These genes encoded putative proteins that may be involved in the synthesis of cell wall-associated macromolecules, in adhesion to host cells, or in protection from host cationic antimicrobial peptides. This report presents the first successful expression profiling of coregulated transcriptomes of bacterial and host genes during a clostridial myonecrosis infection and provides new insights into disease pathogenesis and host-pathogen interactions.IMPORTANCEClostridium perfringensis the causative agent of traumatic clostridial myonecrosis, or gas gangrene. In this study, we carried out transcriptional analysis of both the host and the bacterial pathogen in a mouse myonecrosis infection. The results showed that in comparison to mock-infected control tissues, muscle tissues fromC. perfringens-infected mice had a significantly altered gene expression profile. In particular, the expression of many genes involved in the innate immune system was upregulated. Comparison of the expression profiles ofC. perfringenscells isolated from the infected tissues with those from equivalent broth cultures identified many potential virulence genes that were significantly upregulatedin vivo. These studies have provided a new understanding of the range of factors involved in host-pathogen interactions in a myonecrosis infection.

scholarly journals cDNA Microarray Analysis of Host-Pathogen Interactions in a Porcine In Vitro Model for Toxoplasma gondii Infection

2006 ◽  
Vol 74 (7) ◽  
pp. 4254-4265 ◽  
Author(s):  
Margaret Okomo-Adhiambo ◽  
Craig Beattie ◽  
Anette Rink
Keyword(s):  
Toxoplasma Gondii ◽  
Cdna Microarray ◽  
Host Cells ◽  
Host Pathogen Interactions ◽  
Nutrient Metabolism ◽  
Expression Ratio ◽  
Reverse Transcription Pcr ◽  
Host Pathogen ◽  
Toxoplasma Gondii Infection

ABSTRACT Toxoplasma gondii induces the expression of proinflammatory cytokines, reorganizes organelles, scavenges nutrients, and inhibits apoptosis in infected host cells. We used a cDNA microarray of 420 annotated porcine expressed sequence tags to analyze the molecular basis of these changes at eight time points over a 72-hour period in porcine kidney epithelial (PK13) cells infected with T. gondii. A total of 401 genes with Cy3 and Cy5 spot intensities of ≥500 were selected for analysis, of which 263 (65.6%) were induced ≥2-fold (expression ratio, ≥2.0; P ≤ 0.05 [t test]) over at least one time point and 48 (12%) were significantly down-regulated. At least 12 functional categories of genes were modulated (up- or down-regulated) by T. gondii. The majority of induced genes were clustered as transcription, signal transduction, host immune response, nutrient metabolism, and apoptosis related. The expression of selected genes altered by T. gondii was validated by quantitative real-time reverse transcription-PCR. These results suggest that significant changes in gene expression occur in response to T. gondii infection in PK13 cells, facilitating further analysis of host-pathogen interactions in toxoplasmosis in a secondary host.

scholarly journals In VitroAnalyses of the Effects of Heparin and Parabens on Candida albicans Biofilms and Planktonic Cells

2011 ◽  
Vol 56 (1) ◽  
pp. 148-153 ◽  
Author(s):  
Marisa H. Miceli ◽  
Stella M. Bernardo ◽  
T. S. Neil Ku ◽  
Carla Walraven ◽  
Samuel A. Lee
Keyword(s):  
Candida Albicans ◽  
Metabolic Activity ◽  
Biofilm Formation ◽  
High Dose ◽  
Dependent Manner ◽  
Planktonic Cells ◽  
Content Type ◽  
Heparin Sodium ◽  
The Individual

ABSTRACTInfections and thromboses are the most common complications associated with central venous catheters. Suggested strategies for prevention and management of these complications include the use of heparin-coated catheters, heparin locks, and antimicrobial lock therapy. However, the effects of heparin onCandida albicansbiofilms and planktonic cells have not been previously studied. Therefore, we sought to determine thein vitroeffect of a heparin sodium preparation (HP) on biofilms and planktonic cells ofC. albicans. Because HP contains two preservatives, methyl paraben (MP) and propyl paraben (PP), these compounds and heparin sodium without preservatives (Pure-H) were also tested individually. The metabolic activity of the mature biofilm after treatment was assessed using XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction and microscopy. Pure-H, MP, and PP caused up to 75, 85, and 60% reductions of metabolic activity of the mature preformedC. albicansbiofilms, respectively. Maximal efficacy against the mature biofilm was observed with HP (up to 90%) compared to the individual compounds (P< 0.0001). Pure-H, MP, and PP each inhibitedC. albicansbiofilm formation up to 90%. A complete inhibition of biofilm formation was observed with HP at 5,000 U/ml and higher. When tested against planktonic cells, each compound inhibited growth in a dose-dependent manner. These data indicated that HP, MP, PP, and Pure-H havein vitroantifungal activity againstC. albicansmature biofilms, formation of biofilms, and planktonic cells. Investigation of high-dose heparin-based strategies (e.g., heparin locks) in combination with traditional antifungal agents for the treatment and/or prevention ofC. albicansbiofilms is warranted.

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