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Sebolai OM, Pohl CH, Kock LJF, Chaturvedi V, del Poeta M. The presence of 3-hydroxy oxylipins in pathogenic microbes. Prostaglandins Other Lipid Mediat 2011; 97:17-21. [PMID: 22108026 DOI: 10.1016/j.prostaglandins.2011.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 10/31/2011] [Accepted: 11/01/2011] [Indexed: 10/15/2022]
Abstract
There is a sufficient body of work documenting the distribution of 3-hydroxy oxylipins in microbes. However, there is limited information on the role of these compounds in microbial pathogenesis. When derived from mammalian cells, these compounds regulate patho-biological processes, thus an understanding of 3-hydroxy oxylipin function and metabolism could prove important in shedding light on how these compounds mediate cellular pathology and physiology. This could present 3-hydroxy oxylipin biosynthetic pathways as targets for drug development. In this minireview, we interrogate the relevant yeast and bacterial 3-hydroxy oxylipin literature in order to appreciate how these compounds may influence the inflammatory response leading to disease development.
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Affiliation(s)
- Olihile M Sebolai
- Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, 205 Nelson Mandela Drive, Park West, Bloemfontein 9301, South Africa.
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52
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Frases S, Viana NB, Casadevall A. Biophysical methods for the study of microbial surfaces. Front Microbiol 2011; 2:207. [PMID: 22013430 PMCID: PMC3189542 DOI: 10.3389/fmicb.2011.00207] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 09/17/2011] [Indexed: 01/11/2023] Open
Abstract
The challenge in studying the surface architecture of different microbial pathogens is to integrate the most current biochemical, spectroscopic, microscopic, and processing techniques. Individually these methods have insufficient sensitivity to reveal complex structures, such as branched, large, viscous polymers with a high structure hydration, size, and complexity. However, when used in combination biophysical techniques are our primary source of information for understanding polydisperse molecules and complex microbial surfaces. Biophysical methods seek to explain biological function in terms of the molecular structures and properties of specific molecules. The sizes of the molecules found in microbial surfaces vary greatly from small fatty acids and sugars to macromolecules like proteins, polysaccharides, and pigments, such as melanin. These molecules, which comprise the building blocks of living organisms, assemble into cells, tissues, and whole organisms by forming complex individual structures with dimensions from 10 to 10,000 nm and larger. Biophysics is directed to determining the structure of specific biological molecules and of the larger structures into which they assemble. Some of this effort involves developing new methods, adapting old methods and building new instruments for viewing these structures. The description of biophysical properties in an experimental model where, properties such as flexibility, hydrodynamic characteristics, and size can be precisely determined is of great relevance to study the affinity of the surfaces with biologically active and inert substrates and the interaction with host molecules. Furthermore, this knowledge could establish the abilities of different molecules and their structures to differentially activate cellular responses. Recent studies in the fungal pathogen Cryptococcus neoformans have demonstrated that the physical properties of its unique polysaccharide capsule correlate with the biological functions associated with the intact capsule and the components comprising the capsule. In this review, we describe the application of biophysical techniques to study and characterize this highly hydrated and fragile fungal surface structure.
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Affiliation(s)
- Susana Frases
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
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53
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García-Rodas R, Casadevall A, Rodríguez-Tudela JL, Cuenca-Estrella M, Zaragoza O. Cryptococcus neoformans capsular enlargement and cellular gigantism during Galleria mellonella infection. PLoS One 2011; 6:e24485. [PMID: 21915338 PMCID: PMC3168503 DOI: 10.1371/journal.pone.0024485] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 08/11/2011] [Indexed: 12/03/2022] Open
Abstract
We have studied infection of Cryptococcus neoformans in the non-vertebrate host Galleria mellonella with particular interest in the morphological response of the yeast. Inoculation of C. neoformans in caterpillars induced a capsule-independent increase in haemocyte density 2 h after infection. C. neoformans manifested a significant increase in capsule size after inoculation into the caterpillar. The magnitude of capsule increase depended on the temperature, being more pronounced at 37°C than at 30°C, which correlated with an increased virulence of the fungus and reduced phagocytosis at 37°C. Capsule enlargement impaired phagocytosis by haemocytes. Incubation of the yeast in G. mellonella extracts also resulted in capsule enlargement, with the polar lipidic fraction having a prominent role in this effect. During infection, the capsule decreased in permeability. A low proportion of the cells (<5%) recovered from caterpillars measured more than 30 µm and were considered giant cells. Giant cells recovered from mice were able to kill the caterpillars in a manner similar to regular cells obtained from in vivo or grown in vitro, establishing their capacity to cause disease. Our results indicate that the morphological transitions exhibited by C. neoformans in mammals also occur in a non-vertebrate host system. The similarities in morphological transitions observed in different animal hosts and in their triggers are consistent with the hypothesis that the cell body and capsular responses represent an adaptation of environmental survival strategies to pathogenesis.
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Affiliation(s)
- Rocío García-Rodas
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Arturo Casadevall
- Department of Microbiology and Immunology and Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Juan Luís Rodríguez-Tudela
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Manuel Cuenca-Estrella
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Oscar Zaragoza
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
- * E-mail:
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Rodrigues ML, Nimrichter L, Cordero RJB, Casadevall A. Fungal polysaccharides: biological activity beyond the usual structural properties. Front Microbiol 2011; 2:171. [PMID: 21886639 PMCID: PMC3155879 DOI: 10.3389/fmicb.2011.00171] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 07/28/2011] [Indexed: 12/31/2022] Open
Abstract
Studies on structure and function of polysaccharides in biological systems classically involve sequence and compositional analyses, anomeric configuration, type of glycosidic linkage, and presence of substituents. Recent studies, however, indicates that other structural parameters, so far little explored, can directly influence the biological activity of microbial polysaccharides. Among these parameters, we highlight the molecular dimensions of Cryptococcus neoformans polysaccharides, which appear to be inversely correlated with their immunobiological activity. These recent observations raise new concepts about the structure and function of polysaccharides, which stimulates the design of new experimental approaches and suggests previously unknown applications.
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Affiliation(s)
- Marcio L Rodrigues
- Laboratório de Estudos Integrados em Bioquímica Microbiana, Instituto de Microbiologia Professor Paulo de Góes, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil
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55
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Kmetzsch L, Joffe LS, Staats CC, de Oliveira DL, Fonseca FL, Cordero RJB, Casadevall A, Nimrichter L, Schrank A, Vainstein MH, Rodrigues ML. Role for Golgi reassembly and stacking protein (GRASP) in polysaccharide secretion and fungal virulence. Mol Microbiol 2011; 81:206-18. [PMID: 21542865 DOI: 10.1111/j.1365-2958.2011.07686.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Secretion of virulence factors is a critical mechanism for the establishment of cryptococcosis, a disease caused by the yeast pathogen Cryptococcus neoformans. One key virulence strategy of C. neoformans is the release of glucuronoxylomannan (GXM), a capsule-associated immune-modulatory polysaccharide that reaches the extracellular space through secretory vesicles. Golgi reassembly and stacking protein (GRASP) is required for unconventional protein secretion mechanisms in different eukaryotic cells, but its role in polysaccharide secretion is unknown. This study demonstrates that a C. neoformans functional mutant of a GRASP orthologue had attenuated virulence in an animal model of cryptococcosis, in comparison with wild-type (WT) and reconstituted cells. Mutant cells manifested altered Golgi morphology, failed to produce typical polysaccharide capsules and showed a reduced ability to secrete GXM both in vitro and during animal infection. Isolation of GXM from cultures of WT, reconstituted or mutant strains revealed that the GRASP orthologue mutant produced polysaccharides with reduced dimensions. The mutant was also more efficiently associated to and killed by macrophages than WT and reconstituted cells. These results demonstrate that GRASP, a protein involved in unconventional protein secretion, is also required for polysaccharide secretion and virulence in C. neoformans.
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Affiliation(s)
- Lívia Kmetzsch
- Centro de Biotecnologia Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Av Bento Gonçalves 9500, 43421, Caixa Postal 15005, Porto Alegre, RS 91501-970, Brazil
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Cordero RJB, Frases S, Guimaräes AJ, Rivera J, Casadevall A. Evidence for branching in cryptococcal capsular polysaccharides and consequences on its biological activity. Mol Microbiol 2011; 79:1101-17. [PMID: 21208301 DOI: 10.1111/j.1365-2958.2010.07511.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The encapsulated fungus Cryptococcus neoformans is a common cause of life-threatening disease in immunocompromised individuals. Its major virulence determinant is the polysaccharide (PS) capsule. An unsolved problem in cryptococcal biology is whether the PSs composing the capsule are linear or complex branched polymers, as well as the implications of this structural composition in pathogenesis. In this study we approached the problem by combining static and dynamic light scattering, viscosity analysis, and high-resolution microscopy and correlated the findings with biological properties. Analysis of the dependence of capsular PS molecular mass and the radius of gyration provided strong evidence against a simple linear PS configuration. Shape factors calculated from light scattering measurements in solution revealed values consistent with polymer branching. Furthermore, viscosity measurements provided complementary evidence for structural branching. Electron microscopy showed PS spherical-like structures similar to other branched PS. Finally, we show that the capacity of capsular PS to interfere in complement-mediated phagocytosis, inhibit nitric oxide production by macrophage-like cells, protect against reactive oxygen species, antibody reactivity and half-life in serum were influenced by the degree of branching, providing evidence for the notion that PS branching is an important parameter in determining the biological activity of C. neoformans PS.
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Affiliation(s)
- Radames J B Cordero
- Department of Microbiology and Immunology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY, USA
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57
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Bacillus anthracis produces membrane-derived vesicles containing biologically active toxins. Proc Natl Acad Sci U S A 2010. [PMID: 20956325 DOI: 10.1073/pnas.1008843107.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Extracellular vesicle production is a ubiquitous process in Gram-negative bacteria, but little is known about such process in Gram-positive bacteria. We report the isolation of extracellular vesicles from the supernatants of Bacillus anthracis, a Gram-positive bacillus that is a powerful agent for biological warfare. B. anthracis vesicles formed at the outer layer of the bacterial cell had double-membrane spheres and ranged from 50 to 150 nm in diameter. Immunoelectron microscopy with mAbs to protective antigen, lethal factor, edema toxin, and anthrolysin revealed toxin components and anthrolysin in vesicles, with some vesicles containing more than one toxin component. Toxin-containing vesicles were also visualized inside B. anthracis-infected macrophages. ELISA and immunoblot analysis of vesicle preparations confirmed the presence of B. anthracis toxin components. A mAb to protective antigen protected macrophages against vesicles from an anthrolysin-deficient strain, but not against vesicles from Sterne 34F2 and Sterne δT strains, consistent with the notion that vesicles delivered both toxin and anthrolysin to host cells. Vesicles were immunogenic in BALB/c mice, which produced a robust IgM response to toxin components. Furthermore, vesicle-immunized mice lived significantly longer than controls after B. anthracis challenge. Our results indicate that toxin secretion in B. anthracis is, at least, partially vesicle-associated, thus allowing concentrated delivery of toxin components to target host cells, a mechanism that may increase toxin potency. Our observations may have important implications for the design of vaccines, for passive antibody strategies, and provide a previously unexplored system for studying secretory pathways in Gram-positive bacteria.
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Bacillus anthracis produces membrane-derived vesicles containing biologically active toxins. Proc Natl Acad Sci U S A 2010; 107:19002-7. [PMID: 20956325 DOI: 10.1073/pnas.1008843107] [Citation(s) in RCA: 274] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Extracellular vesicle production is a ubiquitous process in Gram-negative bacteria, but little is known about such process in Gram-positive bacteria. We report the isolation of extracellular vesicles from the supernatants of Bacillus anthracis, a Gram-positive bacillus that is a powerful agent for biological warfare. B. anthracis vesicles formed at the outer layer of the bacterial cell had double-membrane spheres and ranged from 50 to 150 nm in diameter. Immunoelectron microscopy with mAbs to protective antigen, lethal factor, edema toxin, and anthrolysin revealed toxin components and anthrolysin in vesicles, with some vesicles containing more than one toxin component. Toxin-containing vesicles were also visualized inside B. anthracis-infected macrophages. ELISA and immunoblot analysis of vesicle preparations confirmed the presence of B. anthracis toxin components. A mAb to protective antigen protected macrophages against vesicles from an anthrolysin-deficient strain, but not against vesicles from Sterne 34F2 and Sterne δT strains, consistent with the notion that vesicles delivered both toxin and anthrolysin to host cells. Vesicles were immunogenic in BALB/c mice, which produced a robust IgM response to toxin components. Furthermore, vesicle-immunized mice lived significantly longer than controls after B. anthracis challenge. Our results indicate that toxin secretion in B. anthracis is, at least, partially vesicle-associated, thus allowing concentrated delivery of toxin components to target host cells, a mechanism that may increase toxin potency. Our observations may have important implications for the design of vaccines, for passive antibody strategies, and provide a previously unexplored system for studying secretory pathways in Gram-positive bacteria.
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