1
|
Shang Y, Wu X, Wang X, Dou H, Wei Q, Ma S, Sun G, Wang L, Sha W, Zhang H. Environmental factors and stochasticity affect the fungal community structures in the water and sediments of Hulun Lake, China. Ecol Evol 2022; 12:e9510. [PMID: 36415879 PMCID: PMC9674472 DOI: 10.1002/ece3.9510] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 10/06/2022] [Accepted: 10/27/2022] [Indexed: 08/26/2023] Open
Abstract
Aquatic fungi form both morphologically and ecologically diverse communities. However, lake ecosystems are frequently overlooked as fungal habitats, despite the potentially important role of fungi in matter cycling and energy flow. Hulun Lake is a typical example of a seasonal glacial lake; however, previous studies have only focused on bacteria in this ecosystem. Therefore, in the current study, internal transcribed spacer ribosomal RNA (ITS rRNA) gene high-throughput sequencing was used to investigate the fungal communities in paired water and sediment samples from the Hulun Lake Basin in China. A significant difference was found between the fungal communities of the two sample types. Across all samples, we identified nine phyla, 30 classes, 78 orders, 177 families, and 307 genera. The dominant phyla in the lake were Ascomycota, Basidiomycota and Chytridiomycota. Our results show that both water and sediments have very high connectivity, are dominated by positive interactions, and have similar interaction patterns. The fungal community structures were found to be significantly affected by environmental factors (temperature, chemical oxygen demand, electrical conductivity, total phosphorus, and pH). In addition, the dispersal limitations of the fungi affected the structure of the fungal communities, and it was revealed that stochasticity is more important than deterministic mechanisms in influencing the structure and function of fungal communities. This study provides unique theoretical support for the study of seasonally frozen lake fungal communities and a scientific basis for the future management and protection of Hulun Lake.
Collapse
Affiliation(s)
| | - Xiaoyang Wu
- College of Life SciencesQufu Normal UniversityQufuChina
| | - Xibao Wang
- College of Life SciencesQufu Normal UniversityQufuChina
| | - Huashan Dou
- Hulunbuir Academy of Inland Lakes in Northern Cold & Arid AreasHulunbuirChina
| | - Qinguo Wei
- College of Life SciencesQufu Normal UniversityQufuChina
| | - Shengchao Ma
- College of Life SciencesQufu Normal UniversityQufuChina
| | - Guolei Sun
- College of Life SciencesQufu Normal UniversityQufuChina
| | - Lidong Wang
- College of Life SciencesQufu Normal UniversityQufuChina
| | - Weilai Sha
- College of Life SciencesQufu Normal UniversityQufuChina
| | - Honghai Zhang
- College of Life SciencesQufu Normal UniversityQufuChina
| |
Collapse
|
2
|
Abstract
Cryptosporidium is a protozoan parasite of medical and veterinary importance that causes gastroenteritis in a variety of vertebrate hosts. Several studies have reported different degrees of pathogenicity and virulence among Cryptosporidium species and isolates of the same species as well as evidence of variation in host susceptibility to infection. The identification and validation of Cryptosporidium virulence factors have been hindered by the renowned difficulties pertaining to the in vitro culture and genetic manipulation of this parasite. Nevertheless, substantial progress has been made in identifying putative virulence factors for Cryptosporidium. This progress has been accelerated since the publication of the Cryptosporidium parvum and C. hominis genomes, with the characterization of over 25 putative virulence factors identified by using a variety of immunological and molecular techniques and which are proposed to be involved in aspects of host-pathogen interactions from adhesion and locomotion to invasion and proliferation. Progress has also been made in the contribution of host factors that are associated with variations in both the severity and risk of infection. Here we provide a review comprised of the current state of knowledge on Cryptosporidium infectivity, pathogenesis, and transmissibility in light of our contemporary understanding of microbial virulence.
Collapse
|
3
|
Tseng HK, Liu CP, Price MS, Jong AY, Chang JC, Toffaletti DL, Betancourt-Quiroz M, Frazzitta AE, Cho WL, Perfect JR. Identification of genes from the fungal pathogen Cryptococcus neoformans related to transmigration into the central nervous system. PLoS One 2012; 7:e45083. [PMID: 23028773 PMCID: PMC3447876 DOI: 10.1371/journal.pone.0045083] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 08/17/2012] [Indexed: 12/25/2022] Open
Abstract
Background A mouse brain transmigration assessment (MBTA) was created to investigate the central nervous system (CNS) pathogenesis of cryptococcal meningoencephalitis. Methodology/Principal Findings Two cryptococcal mutants were identified from a pool of 109 pre-selected mutants that were signature-tagged with the nourseothricin acetyltransferase (NAT) resistance cassette. These two mutants displayed abnormal transmigration into the central nervous system. One mutant displaying decreased transmigration contains a null mutation in the putative FNX1 gene, whereas the other mutant possessing a null mutation in the putative RUB1 gene exhibited increased transmigration into the brain. Two macrophage adhesion-defective mutants in the pool, 12F1 and 3C9, showed reduced phagocytosis by macrophages, but displayed no defects in CNS entry suggesting that transit within macrophages (the “Trojan horse” model of CNS entry) is not the primary mechanism for C. neoformans migration into the CNS in this MBTA. Conclusions/Significance This research design provides a new strategy for genetic impact studies on how Cryptococcus passes through the blood-brain barrier (BBB), and the specific isolated mutants in this assay support a transcellular mechanism of CNS entry.
Collapse
Affiliation(s)
- Hsiang-Kuang Tseng
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
- Division of Infectious Diseases, Department of Internal Medicine, Mackay Memorial Hospital, Taipei, Taiwan
- Department of Medicine, Mackay Medical College, New Taipei, Taiwan
| | - Chang-Pan Liu
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Michael S. Price
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, United States of America
| | - Ambrose Y. Jong
- Division of Hematology-Oncology, The Saban Research Institute, Children’s Hospital Los Angeles, Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Jui-Chih Chang
- Division of Thoracic and Cardiovascular Surgery, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Dena L. Toffaletti
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, United States of America
| | - Marisol Betancourt-Quiroz
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, United States of America
| | - Aubrey E. Frazzitta
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, United States of America
| | - Wen-Long Cho
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Medicine, Mackay Medical College, New Taipei, Taiwan
- * E-mail: (WLC); (JRP)
| | - John R. Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC, United States of America
- * E-mail: (WLC); (JRP)
| |
Collapse
|
4
|
Bandara HMHN, Lam OLT, Jin LJ, Samaranayake L. Microbial chemical signaling: a current perspective. Crit Rev Microbiol 2012; 38:217-49. [PMID: 22300377 DOI: 10.3109/1040841x.2011.652065] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Communication among microorganisms is mediated through quorum sensing. The latter is defined as cell-density linked, coordinated gene expression in microbial populations as a response to threshold signal concentrations followed by induction of a synchronized population response. This phenomenon is used by a variety of microbes to optimize their survival in a constantly challenging, dynamic milieu, by correlating individual cellular functions to community-based requirements. The synthesis, secretion, and perception of quorum-sensing molecules and their target response play a pivotal role in quorum sensing and are tightly controlled by complex, multilayered and interconnected signal transduction pathways that regulate diverse cellular functions. Quorum sensing exemplifies interactive social behavior innate to the microbial world that controls features such as, virulence, biofilm maturation, antibiotic resistance, swarming motility, and conjugal plasmid transfer. Over the past two decades, studies have been performed to rationalize bacterial cell-to-cell communication mediated by structurally and functionally diverse small molecules. This review describes the theoretical aspects of cellular and quorum-sensing mechanisms that affect microbial physiology and pathobiology.
Collapse
Affiliation(s)
- H M H N Bandara
- Oral Biosciences, Prince Philip Dental Hospital, 34, Hospital Road, Sai Ying Pun, Hong Kong
| | | | | | | |
Collapse
|
5
|
The molecular pathogenicity of Fusarium keratitis: a fungal transcriptional regulator promotes hyphal penetration of the cornea. Cornea 2011; 29:1440-4. [PMID: 20856109 DOI: 10.1097/ico.0b013e3181d8383a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
PURPOSE The pathogenic mechanisms of fungal infection during human keratomycosis were investigated in an ex vivo corneal model that used strains of Fusarium oxysporum differing in the production of a fungal transcription factor. METHODS A pacC loss-of-function mutant and a pacC dominant-activating mutant were constructed from a wild-type isolate of F. oxysporum, and the 3 strains were characterized by in vitro growth kinetics. Twenty-seven human donor corneas maintained in tissue culture were superficially scarified and topically inoculated with the wild-type, the pacC loss-of-function mutant, or the pacC dominant-activating strains. Relative hyphal invasion into the stroma was compared histopathologically in corneal sections. RESULTS F. oxysporum strains demonstrated comparable exponential growth rates in vitro. Wild-type F. oxysporum invaded into the corneal tissue within 1 day and penetrated through the anterior stroma during the next 4 days. The pacC loss-of-function mutant invaded explanted corneas significantly less than the wild-type strain on day 1 (P < 0.0001) and on day 3 (P = 0.0003). The pacC dominant-activating strain adhered and penetrated explanted corneas similar to the wild-type strain. CONCLUSIONS The PacC pathway regulating the transcription of fungal genes allows fungal adaptation to the ocular surface and enables invasion of the injured cornea by F. oxysporum.
Collapse
|
6
|
Arana DM, Prieto D, Román E, Nombela C, Alonso-Monge R, Pla J. The role of the cell wall in fungal pathogenesis. Microb Biotechnol 2008; 2:308-20. [PMID: 21261926 PMCID: PMC3815752 DOI: 10.1111/j.1751-7915.2008.00070.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Fungal infections are a serious health problem. In recent years, basic research is focusing on the identification of fungal virulence factors as promising targets for the development of novel antifungals. The wall, as the most external cellular component, plays a crucial role in the interaction with host cells mediating processes such as adhesion or phagocytosis that are essential during infection. Specific components of the cell wall (called PAMPs) interact with specific receptors in the immune cell (called PRRs), triggering responses whose molecular mechanisms are being elucidated. We review here the main structural carbohydrate components of the fungal wall (glucan, mannan and chitin), how their biogenesis takes place in fungi and the specific receptors that they interact with. Different model fungal pathogens are chosen to illustrate the functional consequences of this interaction. Finally, the identification of the key components will have important consequences in the future and will allow better approaches to treat fungal infections.
Collapse
Affiliation(s)
- David M Arana
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, E-28040 Madrid, Spain
| | | | | | | | | | | |
Collapse
|
7
|
Maranhão FCA, Paião FG, Martinez-Rossi NM. Isolation of transcripts over-expressed in human pathogen Trichophyton rubrum during growth in keratin. Microb Pathog 2007; 43:166-72. [PMID: 17590307 DOI: 10.1016/j.micpath.2007.05.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Accepted: 05/14/2007] [Indexed: 01/08/2023]
Abstract
Trichophyton rubrum is a cosmopolitan and anthropophilic fungus able to invade keratinized tissue, causing infection in human skin and nails. This work evaluated the changes in the extracellular pH during its growth in keratin (after 6, 12, 24, 48, 72h and 7 days) at initial pH 5.0. We observed a gradual increase of basal pH under keratin exposure when compared to glucose condition. Also, we identified 576T. rubrum transcripts differentially expressed by subtractive suppression hybridization (SSH) using conidia cultivated for 72h in keratin as tester, and cultivated in glucose as driver. The over-expression of 238 transcripts obtained under keratin condition was confirmed by macro-array dot-blot, revealing 28 unigenes. Putative proteins encoded by these genes showed similarity to fungi proteins involved in basic metabolism, growth and virulence, i.e., transporters ABC-MDR, MFS and ATPase of copper, NIMA interactive protein, Gag-Pol polyprotein, virulence factors serine-protease subtilisin and metalloprotease, cytochrome P450, GlcN-6-phosphate deaminase and Hsp30. The upregulation of T. rubrum genes encoding subtilisin, metalloprotease and Gag-Pol polyprotein was also validated by northern blot. The results of this study provide the first insight into genes differentially expressed during T. rubrum grown in keratin that may be involved in fungal pathogenesis.
Collapse
Affiliation(s)
- Fernanda C A Maranhão
- Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil
| | | | | |
Collapse
|
8
|
Nickerson KW, Atkin AL, Hornby JM. Quorum sensing in dimorphic fungi: farnesol and beyond. Appl Environ Microbiol 2006; 72:3805-13. [PMID: 16751484 PMCID: PMC1489610 DOI: 10.1128/aem.02765-05] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Kenneth W Nickerson
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588-0666, USA.
| | | | | |
Collapse
|
9
|
de Llanos R, Fernández-Espinar MT, Querol A. A comparison of clinical and food Saccharomyces cerevisiae isolates on the basis of potential virulence factors. Antonie van Leeuwenhoek 2006; 90:221-31. [PMID: 16871421 DOI: 10.1007/s10482-006-9077-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2005] [Accepted: 04/05/2006] [Indexed: 10/24/2022]
Abstract
Saccharomyces cerevisiae is the most widely used yeast in industrial/commercial food and beverage production and is even consumed as a nutritional supplement. Various cases of fungemia caused by this yeast species in severely debilitated traumatized or immune-deficient patients have been reported in recent years, suggesting that this species could be an opportunistic pathogen in such patients. To determine whether the industrial S. cerevisiae strains can be included in this virulent group of strains, we carried out a comparative study between clinical and industrial yeasts based on the various phenotypic traits associated with pathogenicity in two other yeast species (Candida albicans and Cryptococcus neoformans). The majority of the clinical isolates were found to secrete higher levels of protease and phospholipase, grow better at 42 degrees C and show strong pseudohyphal growth relative to industrial yeasts. However three industrial yeast strains, one commercial wine strain, baker's yeast and one commercial strain of S. cerevisiae (var. boulardii), were exceptions and based on their physiological traits these yeasts would appear to be related to clinical strains.
Collapse
Affiliation(s)
- Rosa de Llanos
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de los Alimentos, CSIC, P.O. Box 73, 46100, Burjassot, Valencia, Spain
| | | | | |
Collapse
|
10
|
Abstract
Comparative analyses of fungal genomes and molecular research on genes associated with fungal viability and virulence has led to the identification of many putative targets for novel antifungal agents. So far the rational approach to antifungal discovery, in which compounds are optimized against an individual target then progressed to efficacy against intact fungi and ultimately to infected humans has delivered no new agents. However, the approach continues to hold promise for the future. This review critically assesses the molecular target-based approach to antifungal discovery, outlines problems and pitfalls inherent in the genomics and target discovery strategies and describes the status of heavily investigated examples of target-based research.
Collapse
Affiliation(s)
- Frank C Odds
- Aberdeen Fungal Group, Institute of Medical Sciences, Department of Molecular and Cell Biology, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK.
| |
Collapse
|