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Yee EA, Ross RL, Santiago-Tirado FH. Phenotypic characterization of HAM1, a novel mating regulator of the fungal pathogen Cryptococcus neoformans. bioRxiv 2024:2023.09.18.558251. [PMID: 38585947 PMCID: PMC10996478 DOI: 10.1101/2023.09.18.558251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Cryptococcus neoformans is a fungal pathogen responsible for >200,000 yearly cases with a mortality as high as 81%. This burden results, in part, from an incomplete understanding of its pathogenesis and ineffective antifungal treatments; hence, there is a pressing need to understand the biology and host interactions of this yeast to develop improved treatments. Protein palmitoylation is important for cryptococcal virulence, and we previously identified the substrates of its main palmitoyl transferase. One of them was encoded by the uncharacterized gene CNAG_02129. In the filamentous fungus Neurospora crassa, a homolog of this gene named HAM-13 plays a role in proper cellular communication and filament fusion. In Cryptococcus, cellular communication is essential during mating, therefore we hypothesized that CNAG_02129, which we named HAM1, may play a role in mating. We found that ham1Δ mutants produce more fusion products during mating, filament more robustly, and exhibit competitive fitness defects under mating and non-mating conditions. Additionally, we found several differences with the major virulence factor, the polysaccharide capsule, that may affect virulence, consistent with prior studies linking virulence to mating. We observed that ham1Δ mutants have decreased capsule attachment and transfer but exhibit higher amounts of exopolysaccharide shedding and biofilm production. Lastly, HAM1 expression is significantly lower in mating media relative to non-mating conditions, consistent with it acting as a negative regulator of mating. Understanding the connection between mating and virulence in C. neoformans may open new avenues of investigation into ways to improve the treatment of this disease.
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Affiliation(s)
- Elizabeth Arsenault Yee
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556
- E Arsenault Yee and RL Ross contributed equally to this work, and order was determined by who initiated the study (EAY) and who brought it to completion (RLR)
| | - Robbi L. Ross
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556
- E Arsenault Yee and RL Ross contributed equally to this work, and order was determined by who initiated the study (EAY) and who brought it to completion (RLR)
| | - Felipe H. Santiago-Tirado
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana 46556
- Warren Center for Drug Discovery, University of Notre Dame, Notre Dame, Indiana 46556
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Mazumdar D, Sarma A, Medhi D, Dutta R, Kataki M, Baishya L, Dutta BS, Saikia L. Capsular typing of Streptococcus pneumoniae isolated from clinical specimens in Gauhati Medical College and hospital, Assam, India. Indian J Med Microbiol 2023; 44:100350. [PMID: 37356826 DOI: 10.1016/j.ijmmb.2023.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 12/21/2022] [Accepted: 01/16/2023] [Indexed: 06/27/2023]
Abstract
PURPOSE Streptococcus pneumoniae is an important human respiratory tract pathogen causing pneumococcal diseases in majority of children and adults. The capsule is a significant virulence factor of Pneumococci which determines the bacterial serotype and is the component used for synthesis of pneumococcal vaccines. This cross-sectional study aimed to isolate Streptococcus pneumoniae from clinical samples and determine the occurrence of its circulating serotypes in Assam, North East India. MATERIALS AND METHODS A total of 80 clinical samples were collected from June 2019 to May 2020 from patients clinically suspected from pneumococcal infection and also included samples routinely sent to bacteriology laboratory. Isolation and identification of S. pneumoniae was performed using conventional culture and molecular methods. Antibiotic susceptibility patterns were monitored. Capsular serotyping was performed using PCR of cpsA gene followed by DNA sequencing. RESULTS Majority of the cases suspected of pneumococcal infection belong to the paediatric group aged less than 5 years. Out of 80 samples, 10 (12.50%) were found to be positive by PCR of recP gene. Culture was positive in 80% (8/10) of the total positives. Co-trimoxazole resistance was seen in 33.33% of the isolate from sputum. Serotypes 6A, 6B, 6C and 19F were detected in our region, out of which 6C is a non-vaccine serotype. CONCLUSION Continued surveillance is needed to monitor trends in non-vaccine serotypes that may emerge as highly associated with antibiotic resistance. Also, the need to continuous monitoring of the antibiotic susceptibility of S. pneumoniae in North eastern parts of India is of outmost importance.
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Affiliation(s)
- Dikshita Mazumdar
- Department of Microbiology, Gauhati Medical College & Hospital, Guwahati, 781032, Assam, India.
| | - Anisha Sarma
- Department of Microbiology, Gauhati Medical College & Hospital, Guwahati, 781032, Assam, India.
| | - Devyashree Medhi
- Department of Microbiology, Gauhati Medical College & Hospital, Guwahati, 781032, Assam, India.
| | - Ridip Dutta
- Department of Microbiology, Gauhati Medical College & Hospital, Guwahati, 781032, Assam, India.
| | - Manjuri Kataki
- Department of Microbiology, Gauhati Medical College & Hospital, Guwahati, 781032, Assam, India.
| | - Lakshyasri Baishya
- Department of Microbiology, Gauhati Medical College & Hospital, Guwahati, 781032, Assam, India.
| | - Bornali Sharma Dutta
- Department of Microbiology, Gauhati Medical College & Hospital, Guwahati, 781032, Assam, India.
| | - Lahari Saikia
- Department of Microbiology, Gauhati Medical College & Hospital, Guwahati, 781032, Assam, India.
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Ball B, Woroszchuk E, Sukumaran A, West H, Afaq A, Carruthers-Lay D, Muselius B, Gee L, Langille M, Pladwig S, Kazi S, Hendriks A, Geddes-McAlister J. Proteome and secretome profiling of zinc availability in Cryptococcus neoformans identifies Wos2 as a subtle influencer of fungal virulence determinants. BMC Microbiol 2021; 21:341. [PMID: 34903172 PMCID: PMC8667453 DOI: 10.1186/s12866-021-02410-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 12/03/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Fungal infections impact over 25% of the global population. For the opportunistic fungal pathogen, Cryptococcus neoformans, infection leads to cryptococcosis. In the presence of the host, disease is enabled by elaboration of sophisticated virulence determinants, including polysaccharide capsule, melanin, thermotolerance, and extracellular enzymes. Conversely, the host protects itself from fungal invasion by regulating and sequestering transition metals (e.g., iron, zinc, copper) important for microbial growth and survival. RESULTS Here, we explore the intricate relationship between zinc availability and fungal virulence via mass spectrometry-based quantitative proteomics. We observe a core proteome along with a distinct zinc-regulated protein-level signature demonstrating a shift away from transport and ion binding under zinc-replete conditions towards transcription and metal acquisition under zinc-limited conditions. In addition, we revealed a novel connection among zinc availability, thermotolerance, as well as capsule and melanin production through the detection of a Wos2 ortholog in the secretome under replete conditions. CONCLUSIONS Overall, we provide new biological insight into cellular remodeling at the protein level of C. neoformans under regulated zinc conditions and uncover a novel connection between zinc homeostasis and fungal virulence determinants.
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Affiliation(s)
- B Ball
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, Ontario, N1G 2W1, Canada
| | - E Woroszchuk
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, Ontario, N1G 2W1, Canada
| | - A Sukumaran
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, Ontario, N1G 2W1, Canada
| | - H West
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, Ontario, N1G 2W1, Canada
| | - A Afaq
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, Ontario, N1G 2W1, Canada
| | - D Carruthers-Lay
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, Ontario, N1G 2W1, Canada
| | - B Muselius
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, Ontario, N1G 2W1, Canada
| | - L Gee
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, Ontario, N1G 2W1, Canada
| | - M Langille
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, Ontario, N1G 2W1, Canada
| | - S Pladwig
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, Ontario, N1G 2W1, Canada
| | - S Kazi
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, Ontario, N1G 2W1, Canada
| | - A Hendriks
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, Ontario, N1G 2W1, Canada
| | - J Geddes-McAlister
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, Ontario, N1G 2W1, Canada.
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Sukumaran A, Pladwig S, Geddes-McAlister J. Zinc limitation in Klebsiella pneumoniae profiled by quantitative proteomics influences transcriptional regulation and cation transporter-associated capsule production. BMC Microbiol 2021; 21:43. [PMID: 33568055 PMCID: PMC7874612 DOI: 10.1186/s12866-021-02091-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 01/12/2021] [Indexed: 01/02/2023] Open
Abstract
Background Microbial organisms encounter a variety of environmental conditions, including changes to metal ion availability. Metal ions play an important role in many biological processes for growth and survival. As such, microbes alter their cellular protein levels and secretion patterns in adaptation to a changing environment. This study focuses on Klebsiella pneumoniae, an opportunistic bacterium responsible for nosocomial infections. By using K. pneumoniae, we aim to determine how a nutrient-limited environment (e.g., zinc depletion) modulates the cellular proteome and secretome of the bacterium. By testing virulence in vitro, we provide novel insight into bacterial responses to limited environments in the presence of the host. Results Analysis of intra- and extracellular changes identified 2380 proteins from the total cellular proteome (cell pellet) and 246 secreted proteins (supernatant). Specifically, HutC, a repressor of the histidine utilization operon, showed significantly increased abundance under zinc-replete conditions, which coincided with an expected reduction in expression of genes within the hut operon from our validating qRT-PCR analysis. Additionally, we characterized a putative cation transport regulator, ChaB that showed significantly higher abundance under zinc-replete vs. -limited conditions, suggesting a role in metal ion homeostasis. Phenotypic analysis of a chaB deletion strain demonstrated a reduction in capsule production, zinc-dependent growth and ion utilization, and reduced virulence when compared to the wild-type strain. Conclusions This is first study to comprehensively profile the impact of zinc availability on the proteome and secretome of K. pneumoniae and uncover a novel connection between zinc transport and capsule production in the bacterial system. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02091-8.
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Affiliation(s)
- A Sukumaran
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - S Pladwig
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - J Geddes-McAlister
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
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