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Noyma NP, Silva TP, Chiarini-Garcia H, Amado AM, Roland F, Melo RCN. Potential effects of UV radiation on photosynthetic structures of the bloom-forming cyanobacterium Cylindrospermopsis raciborskii CYRF-01. Front Microbiol 2015; 6:1202. [PMID: 26579108 PMCID: PMC4627488 DOI: 10.3389/fmicb.2015.01202] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 10/15/2015] [Indexed: 11/13/2022] Open
Abstract
Cyanobacteria are aquatic photosynthetic microorganisms. While of enormous ecological importance, they have also been linked to human and animal illnesses around the world as a consequence of toxin production by some species. Cylindrospermopsis raciborskii, a filamentous nitrogen-fixing cyanobacterium, has attracted considerable attention due to its potential toxicity and ecophysiological adaptability. We investigated whether C. raciborskii could be affected by ultraviolet (UV) radiation. Non-axenic cultures of C. raciborskii were exposed to three UV treatments (UVA, UVB, or UVA + UVB) over a 6 h period, during which cell concentration, viability and ultrastructure were analyzed. UVA and UVA + UVB treatments showed significant negative effects on cell concentration (decreases of 56.4 and 64.3%, respectively). This decrease was directly associated with cell death as revealed by a cell viability fluorescent probe. Over 90% of UVA + UVB- and UVA-treated cells died. UVB did not alter cell concentration, but reduced cell viability in almost 50% of organisms. Transmission electron microscopy (TEM) revealed a drastic loss of thylakoids, membranes in which cyanobacteria photosystems are localized, after all treatments. Moreover, other photosynthetic- and metabolic-related structures, such as accessory pigments and polyphosphate granules, were damaged. Quantitative TEM analyses revealed a 95.8% reduction in cell area occupied by thylakoids after UVA treatment, and reduction of 77.6 and 81.3% after UVB and UVA + UVB treatments, respectively. Results demonstrated clear alterations in viability and photosynthetic structures of C. raciborskii induced by various UV radiation fractions. This study facilitates our understanding of the subcellular organization of this cyanobacterium species, identifies specific intracellular targets of UVA and UVB radiation and reinforces the importance of UV radiation as an environmental stressor.
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Affiliation(s)
- Natália P Noyma
- Laboratory of Aquatic Ecology, Department of Biology, Federal University of Juiz de Fora Juiz de Fora, Brazil
| | - Thiago P Silva
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora Juiz de Fora, Brazil
| | - Hélio Chiarini-Garcia
- Laboratory of Structural Biology and Reproduction, Department of Morphology, Federal University of Minas Gerais Belo Horizonte, Brazil
| | - André M Amado
- Laboratory of Limnology, Department of Oceanography and Limnology, Federal University of Rio Grande do Norte Natal, Brazil
| | - Fábio Roland
- Laboratory of Aquatic Ecology, Department of Biology, Federal University of Juiz de Fora Juiz de Fora, Brazil
| | - Rossana C N Melo
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora Juiz de Fora, Brazil
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Skovgaard A, Castro-Mejia JL, Hansen LH, Nielsen DS. Host-Specific and pH-Dependent Microbiomes of Copepods in an Extensive Rearing System. PLoS One 2015; 10:e0132516. [PMID: 26167852 PMCID: PMC4500450 DOI: 10.1371/journal.pone.0132516] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 06/15/2015] [Indexed: 12/14/2022] Open
Abstract
Copepods are to an increasing extent cultivated as feed for mariculture fish larvae with variable production success. In the temperate climate zone, this production faces seasonal limitation due to changing abiotic factors, in particular temperature and light. Furthermore, the production of copepods may be influenced by biotic factors of the culture systems, such as competing microorganisms, harmful algae, or other eukaryotes and prokaryotes that may be non-beneficial for the copepods. In this study, the composition of bacteria associated with copepods was investigated in an extensive outdoor copepod production system. Light microscopy and scanning electron microscopy revealed that bacteria were primarily found attached to the exoskeleton of copepods although a few bacteria were also found in the gut as well as internally in skeletal muscle tissue. Through 16S rRNA gene-targeted denaturing gradient gel electrophoresis (DGGE) analysis, a clear difference was found between the microbiomes of the two copepod species, Acartia tonsa and Centropages hamatus, present in the system. This pattern was corroborated through 454/FLX-based 16S rRNA gene amplicon sequencing of copepod microbiomes, which furthermore showed that the abiotic parameters pH and oxygen concentration in rearing tank water were the key factors influencing composition of copepod microbiomes.
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Affiliation(s)
- Alf Skovgaard
- Department of Veterinary Disease Biology, University of Copenhagen, DK-1870, Frederiksberg, Denmark
- * E-mail:
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Albuquerque AV, Drumond AL, Shao S, Melo RCN, Almeida FRCL, Meistrich ML, Chiarini-Garcia H. A new approach for optimal morphological identification and immunolabeling of spermatogonial cells. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:1304-1311. [PMID: 24834474 DOI: 10.1017/s1431927614000889] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
High quality fixation often inactivates epitopes and gentler fixation can fail to preserve biological structure at the required resolution. For studies of male reproduction, immunofluorescence techniques using paraformaldehyde fixation associated with paraffin as an embedding medium gives good epitope preservation, although the cell becomes morphologically compromised. On the other hand, glutaraldehyde associated with a plastic resin has been used with success to recognize and distinguish each spermatogonial cell subtype, but the antigenic sites become inaccessible to antibodies. Here we describe a new method that provides excellent morphological details of testicular cells while preserving the binding capacity of epitopes. Using a combination of glutaraldehyde and paraformaldehyde as a fixative and LR White resin for embedding, we show that it is possible to clearly recognize spermatogonial subtypes (Aund, A-A4, In and B spermatogonia) on 1-μm thick-sections and to label epitopes such as bromodeoxyuridine, a marker used for cellular cycle studies in the testis. The information gained from this procedure can be critical for understanding spermatogonial process of self-renewal and differentiation.
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Affiliation(s)
- Amanda V Albuquerque
- 1Laboratório de Biologia Estrutural e Reprodução,Departamento de Morfologia,Universidade Federal de Minas Gerais,31.270-901 Belo Horizonte,Brasil
| | - Ana Luiza Drumond
- 1Laboratório de Biologia Estrutural e Reprodução,Departamento de Morfologia,Universidade Federal de Minas Gerais,31.270-901 Belo Horizonte,Brasil
| | - Shan Shao
- 2Department of Experimental Radiation Oncology,MD Anderson Cancer Center,University of Texas,77030 Houston,USA
| | - Rossana C N Melo
- 3Laboratório de Biologia Celular,Departamento de Biologia,Universidade Federal de Juiz de Fora. 36.036-900 - Juiz de Fora,Brasil
| | - Fernanda R C L Almeida
- 1Laboratório de Biologia Estrutural e Reprodução,Departamento de Morfologia,Universidade Federal de Minas Gerais,31.270-901 Belo Horizonte,Brasil
| | - Marvin L Meistrich
- 2Department of Experimental Radiation Oncology,MD Anderson Cancer Center,University of Texas,77030 Houston,USA
| | - Hélio Chiarini-Garcia
- 1Laboratório de Biologia Estrutural e Reprodução,Departamento de Morfologia,Universidade Federal de Minas Gerais,31.270-901 Belo Horizonte,Brasil
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Silva TP, Noyma NP, Duque TLA, Gamalier JP, Vidal LO, Lobão LM, Chiarini-Garcia H, Roland F, Melo RCN. Visualizing aquatic bacteria by light and transmission electron microscopy. Antonie van Leeuwenhoek 2013; 105:1-14. [PMID: 24132727 DOI: 10.1007/s10482-013-0047-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 10/01/2013] [Indexed: 10/26/2022]
Abstract
The understanding of the functional role of aquatic bacteria in microbial food webs is largely dependent on methods applied to the direct visualization and enumeration of these organisms. While the ultrastructure of aquatic bacteria is still poorly known, routine observation of aquatic bacteria by light microscopy requires staining with fluorochromes, followed by filtration and direct counting on filter surfaces. Here, we used a new strategy to visualize and enumerate aquatic bacteria by light microscopy. By spinning water samples from varied tropical ecosystems in a cytocentrifuge, we found that bacteria firmly adhere to regular slides, can be stained by fluorochoromes with no background formation and fast enumerated. Significant correlations were found between the cytocentrifugation and filter-based methods. Moreover, preparations through cytocentrifugation were more adequate for bacterial viability evaluation than filter-based preparations. Transmission electron microscopic analyses revealed a morphological diversity of bacteria with different internal and external structures, such as large variation in the cell envelope and capsule thickness, and presence or not of thylakoid membranes. Our results demonstrate that aquatic bacteria represent an ultrastructurally diverse population and open avenues for easy handling/quantification and better visualization of bacteria by light microscopy without the need of filter membranes.
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Affiliation(s)
- Thiago P Silva
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, 36036-900, Brazil
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Fabrino DL, Ribeiro GA, Teixeira L, Melo RCN. Histological approaches to study tissue parasitism during the experimental Trypanosoma cruzi infection. Methods Mol Biol 2011; 689:69-80. [PMID: 21153787 DOI: 10.1007/978-1-60761-950-5_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
During acute infection with the parasite Trypanosoma cruzi, the causal agent of Chagas' disease, tissue damage is related to intense tissue parasitism. Here we discuss histological approaches for an optimal visualization and quantification of T. cruzi nests in the heart, the main target organ of the parasite. These analyses are important to evaluate the course of the infection in different experimental models and also can be used to investigate parasite colonization and inflammatory processes in other infected tissues and biopsies.
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Affiliation(s)
- Daniela L Fabrino
- Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil.
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Chiarini-Garcia H, Parreira GG, Almeida FRCL. Glycol methacrylate embedding for improved morphological, morphometrical, and immunohistochemical investigations under light microscopy: testes as a model. Methods Mol Biol 2011; 689:3-18. [PMID: 21153783 DOI: 10.1007/978-1-60761-950-5_1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Glycol methacrylate (GMA), a water and ethanol miscible plastic resin, is a medium handy to use for light microscopy embedding that has a number of advantages than paraffin embedding. The GMA improves the histological, morphometrical, and immunohistochemical evaluations, mainly due to the accurate assessment of cytological details. This chapter focuses on our experience in the GMA processing and describes in detail the fixation, embedding, and staining methods that we have been using for testes evaluations.
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Affiliation(s)
- Hélio Chiarini-Garcia
- Laboratory of Structural Biology and Reproduction, Department of Morphology, ICB, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
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