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Sousa JLC, Albuquerque HMT, Silva AMS. Drug Discovery Based on Oxygen and Nitrogen (Non-)Heterocyclic Compounds Developed @LAQV-REQUI MTE/Aveiro. Pharmaceuticals (Basel) 2023; 16:1668. [PMID: 38139794 PMCID: PMC10747949 DOI: 10.3390/ph16121668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/18/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023] Open
Abstract
Artur Silva's research group has a long history in the field of medicinal chemistry. The development of new synthetic methods for oxygen (mostly polyphenols, e.g., 2- and 3-styrylchromones, xanthones, flavones) and nitrogen (e.g., pyrazoles, triazoles, acridones, 4-quinolones) heterocyclic compounds in order to be assessed as antioxidant, anti-inflammatory, antidiabetic, and anticancer agents has been the main core work of our research interests. Additionally, the synthesis of steroid-type compounds as anti-Alzheimer drugs as well as of several chromophores as important dyes for cellular imaging broadened our research scope. In this review article, we intend to provide an enlightened appraisal of all the bioactive compounds and their biological properties that were synthesized and studied by our research group in the last two decades.
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Affiliation(s)
| | | | - Artur M. S. Silva
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (J.L.C.S.); (H.M.T.A.)
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Morkus P, Rassenberg S, Montpetit D, Filipe CDM, Latulippe DR. Tuning the sensitivity of cell-based biosensors for the detection of biocides. CHEMOSPHERE 2023; 331:138740. [PMID: 37088207 DOI: 10.1016/j.chemosphere.2023.138740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 02/04/2023] [Accepted: 04/18/2023] [Indexed: 05/03/2023]
Abstract
The presence of biocides in wastewater can negatively impact the efficiency of wastewater treatment processes, particular the process of nitrification. In this paper, we describe the development of cell-based biosensors (CBBs) with tunable levels of sensitivity for rapidly detecting the presence and predicting the type and concentration of biocides. The CBB assay developed is performed by first exposing a panel of bacterial strains (E. coli, B. subtilis, B. cereus) to the sample being tested and to the control sample without biocide, and then adding a fluorescent dye (LIVE/DEAD BacLight). We then compare the fluorescence signals generated by the two samples, and the differences in the signals indicate the presence of a biocide, as previously reported in the literature. We found that the sensitivity of the CBB assay can be improved by tuning the type/salinity of the buffer used to suspend the cells, and by changing the number of cells used in the assay. These changes improved the level of detection (LOD) of the biocide Cetyltrimethylammonium bromide (CTAB) from 10 ppm to 0.625 ppm and the biocide Grotan® BK from 500 ppm to 7.8 ppm. With the optimized conditions for each strain, we also establish that the combined response from the panel of bacterial strains can be used to predict the type and concentration of biocide sample tested. Additionally, we provide evidence that the response of the tunable CBB assay can be quantitatively measured using a compact, commercially available fluorometer. Overall, the significance of this work will improve point-of-use testing and enable the discrimination between biocide-containing samples of similar toxicity and detection of lower toxicity samples, thereby improving the accuracy of the CBB assay.
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Affiliation(s)
- Patrick Morkus
- Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L7, Canada
| | - Sarah Rassenberg
- Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L7, Canada
| | - Danika Montpetit
- Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L7, Canada
| | - Carlos D M Filipe
- Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L7, Canada
| | - David R Latulippe
- Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L7, Canada.
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Ferreira JRM, Alves M, Sousa B, Vieira SI, Silva AMS, Guieu S, Cunha Â, Nunes da Silva R. Curcumin-based molecular probes for fluorescence imaging of fungi. Org Biomol Chem 2023; 21:1531-1536. [PMID: 36722743 DOI: 10.1039/d2ob01872a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Fluorescence imaging is a powerful and widely used method to visualize and study living organisms. However, fungi are notoriously difficult to visualize using fluorescence microscopy, given that their cell wall represents a diffusion barrier, and the synthetic organic dyes available are very limited when compared to molecular probes available for other organisms. Moreover, these dyes are usually available in only one colour, preventing co-staining experiments. To fill this gap, curcumin-based molecular probes were designed based on the rationale that curcumin is fluorescent and has moderate toxicity toward fungi, implying its ability to cross the cell wall to reach targets in the intracellular compartments. A family of boron diketonate complexes was synthesized, based on a curcumin backbone, tuning their emission color from blue to red. These probes did not present noticeable toxicity to filamentous fungus and, when applied to their visualization, readily entered the cells and precisely localized in sub-cellular organelles, enabling their visualization.
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Affiliation(s)
- Joana R M Ferreira
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Aveiro, Portugal.
| | - Mariana Alves
- iBiMED, Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Bárbara Sousa
- iBiMED, Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Sandra I Vieira
- iBiMED, Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Artur M S Silva
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Aveiro, Portugal.
| | - Samuel Guieu
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Aveiro, Portugal. .,CICECO Aveiro-Institute of Materials, Department of Chemistry, University of Aveiro, Aveiro, Portugal
| | - Ângela Cunha
- CESAM, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Raquel Nunes da Silva
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Aveiro, Portugal. .,iBiMED, Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
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Jiang H, Zhong S, Schwarz P, Chen B, Rao J. Antifungal activity, mycotoxin inhibitory efficacy, and mode of action of hop essential oil nanoemulsion against Fusarium graminearum. Food Chem 2022; 400:134016. [DOI: 10.1016/j.foodchem.2022.134016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/09/2022] [Accepted: 08/22/2022] [Indexed: 10/15/2022]
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The Concentration-Dependent Effects of Essential Oils on the Growth of Fusarium graminearum and Mycotoxins Biosynthesis in Wheat and Maize Grain. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12010473] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The presence of Fusarium fungi and their toxic metabolites in agricultural crops contributes to significant quantitative and qualitative losses of crops, causing a direct threat to human and animal health and life. Modern strategies for reducing the level of fungi and mycotoxins in the food chain tend to rely on natural methods, including plant substances. Essential oils (EOs), due to their complex chemical composition, show high biological activity, including fungistatic properties, which means that they exhibit high potential as a biological plant protection factor. The aim of this study was to determine the fungistatic activity of three EOs against F. graminearum, and the reduction of mycotoxin biosynthesis in corn and wheat grain. All tested EOs effectively suppressed the growth of F. graminearum in concentrations of 5% and 10%. Cinnamon and verbena EOs also effectively reduced the ergosterol (ERG) content in both grains at the concentration of 1%, while at the 0.1% EO concentration, the reduction in the ERG amount depended on the EO type as well as on the grain. The degree of zearalenone (ZEA) reduction was consistent with the inhibition of ERG biosynthesis, while the reduction in deoxynivalenol (DON) was not consistent with this parameter.
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Contreras-Jácquez V, Grajales-Hernández DA, Armendáriz-Ruiz M, Rodríguez-González J, Valenzuela-Soto EM, Asaff-Torres A, Mateos-Díaz JC. In-Cell Crosslinked Enzymes: Improving Bacillus megaterium whole-cell biocatalyst stability for the decarboxylation of ferulic acid. Process Biochem 2021. [DOI: 10.1016/j.procbio.2021.07.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Colosimo R, Warren FJ, Edwards CH, Finnigan TJ, Wilde PJ. The interaction of α-amylase with mycoprotein: Diffusion through the fungal cell wall, enzyme entrapment, and potential physiological implications. Food Hydrocoll 2020. [DOI: 10.1016/j.foodhyd.2020.106018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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O'Connor E, Coates CJ, Eastwood DC, Fitzpatrick DA, Grogan H. FISHing in fungi: Visualisation of mushroom virus X in the mycelium of Agaricus bisporus by fluorescence in situ hybridisation. J Microbiol Methods 2020; 173:105913. [DOI: 10.1016/j.mimet.2020.105913] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 04/01/2020] [Accepted: 04/01/2020] [Indexed: 12/15/2022]
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Ambrico PF, Šimek M, Rotolo C, Morano M, Minafra A, Ambrico M, Pollastro S, Gerin D, Faretra F, De Miccolis Angelini RM. Surface Dielectric Barrier Discharge plasma: a suitable measure against fungal plant pathogens. Sci Rep 2020; 10:3673. [PMID: 32111863 PMCID: PMC7048822 DOI: 10.1038/s41598-020-60461-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 02/03/2020] [Indexed: 01/08/2023] Open
Abstract
Fungal diseases seriously affect agricultural production and the food industry. Crop protection is usually achieved by synthetic fungicides, therefore more sustainable and innovative technologies are increasingly required. The atmospheric pressure low-temperature plasma is a novel suitable measure. We report on the effect of plasma treatment on phytopathogenic fungi causing quantitative and qualitative losses of products both in the field and postharvest. We focus our attention on the in vitro direct inhibitory effect of non-contact Surface Dielectric Barrier Discharge on conidia germination of Botrytis cinerea, Monilinia fructicola, Aspergillus carbonarius and Alternaria alternata. A few minutes of treatment was required to completely inactivate the fungi on an artificial medium. Morphological analysis of spores by Scanning Electron Microscopy suggests that the main mechanism is plasma etching due to Reactive Oxygen Species or UV radiation. Spectroscopic analysis of plasma generated in humid air gives the hint that the rotational temperature of gas should not play a relevant role being very close to room temperature. In vivo experiments on artificially inoculated cherry fruits demonstrated that inactivation of fungal spores by the direct inhibitory effect of plasma extend their shelf life. Pre-treatment of fruits before inoculation improve the resistance to infections maybe by activating defense responses in plant tissues.
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Affiliation(s)
- Paolo F Ambrico
- Consiglio Nazionale delle Ricerche, Istituto per la Scienza e la Tecnologia dei Plasmi, via Amendola 122/D, 70126, Bari, Italy.
| | - Milan Šimek
- Academy of Sciences of the Czech Republic, Institute of Plasma Physics v.v.i., Department of Pulse Plasma Systems, Za Slovankou 1782/3, 18200, Prague, Czech Republic
| | - Caterina Rotolo
- Department of Soil, Plant and Food Sciences, University of Bari ALDO MORO, via G. Amendola 165/A, 70126, Bari, Italy
| | - Massimo Morano
- Department of Soil, Plant and Food Sciences, University of Bari ALDO MORO, via G. Amendola 165/A, 70126, Bari, Italy
| | - Angelantonio Minafra
- Consiglio Nazionale delle Ricerche, Istituto per la Protezione Sostenibile delle Piante, via Amendola 122/D, 70126, Bari, Italy
| | - Marianna Ambrico
- Consiglio Nazionale delle Ricerche, Istituto per la Scienza e la Tecnologia dei Plasmi, via Amendola 122/D, 70126, Bari, Italy
| | - Stefania Pollastro
- Department of Soil, Plant and Food Sciences, University of Bari ALDO MORO, via G. Amendola 165/A, 70126, Bari, Italy
| | - Donato Gerin
- Department of Soil, Plant and Food Sciences, University of Bari ALDO MORO, via G. Amendola 165/A, 70126, Bari, Italy
| | - Francesco Faretra
- Department of Soil, Plant and Food Sciences, University of Bari ALDO MORO, via G. Amendola 165/A, 70126, Bari, Italy.
| | - Rita M De Miccolis Angelini
- Department of Soil, Plant and Food Sciences, University of Bari ALDO MORO, via G. Amendola 165/A, 70126, Bari, Italy
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Card SD, Tapper BA, Lloyd-West C, Wright KM. Assessment of fluorescein-based fluorescent dyes for tracingNeotyphodiumendophytes in planta. Mycologia 2017; 105:221-9. [DOI: 10.3852/12-062] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Stuart D. Card
- Forage Improvement AgResearch Ltd, Grasslands Research Centre, Private Bag 11008, Palmerston North, New Zealand
| | - Brian A. Tapper
- Forage Improvement AgResearch Ltd, Grasslands Research Centre, Private Bag 11008, Palmerston North, New Zealand
| | - Catherine Lloyd-West
- Bioinformatics and Statistics Group, AgResearch Ltd, Grasslands Research Centre, Private Bag 11008, Palmerston North, New Zealand
| | - Kathryn M. Wright
- Forage Improvement AgResearch Ltd, Grasslands Research Centre, Private Bag 11008, Palmerston North, New Zealand
- Bioinformatics and Statistics Group, AgResearch Ltd, Grasslands Research Centre, Private Bag 11008, Palmerston North, New Zealand
- Cell Biology and Imaging Group, The James Hutton Institute, Invergowrie, Dundee, Scotland
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11
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Farzaneh M, Shi ZQ, Ahmadzadeh M, Hu LB, Ghassempour A. Inhibition of the Aspergillus flavus Growth and Aflatoxin B1 Contamination on Pistachio Nut by Fengycin and Surfactin-Producing Bacillus subtilis UTBSP1. THE PLANT PATHOLOGY JOURNAL 2016; 32:209-215. [PMID: 27298596 PMCID: PMC4892817 DOI: 10.5423/ppj.oa.11.2015.0250] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 01/18/2016] [Accepted: 01/20/2016] [Indexed: 06/01/2023]
Abstract
In this study, the treatment of pistachio nuts by Bacillus subtilis UTBSP1, a promising isolate to degrade aflatoxin B1 (AFB1), caused to reduce the growth of Aspergillus flavus R5 and AFB1 content on pistachio nuts. Fluorescence probes revealed that the cell free supernatant fluid from UTBSP1 affects spore viability considerably. Using high-performance liquid chromatographic (HPLC) method, 10 fractions were separated and collected from methanol extract of cell free supernatant fluid. Two fractions showed inhibition zones against A. flavus. Mass spectrometric analysis of the both antifungal fractions revealed a high similarity between these anti-A. flavus compounds and cyclic-lipopeptides of surfactin, and fengycin families. Coproduction of surfactin and fengycin acted in a synergistic manner and consequently caused a strong antifungal activity against A. flavus R5. There was a positive significant correlation between the reduction of A. flavus growth and the reduction of AFB1 contamination on pistachio nut by UTBSP1. The results indicated that fengycin and surfactin-producing B. subtilis UTBSP1 can potentially reduce A. flavus growth and AFB1 content in pistachio nut.
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Affiliation(s)
- Mohsen Farzaneh
- Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Tehran 19835-389,
Iran
- Institute of Food Safety and Quality, Jiangsu Academy of Agricultural Sciences, Nanjing 210014,
China
| | - Zhi-Qi Shi
- Institute of Food Safety and Quality, Jiangsu Academy of Agricultural Sciences, Nanjing 210014,
China
| | - Masoud Ahmadzadeh
- Department of Plant Protection, University of Tehran, Karaj 4111,
Iran
| | - Liang-Bin Hu
- Institute of Food Safety and Quality, Jiangsu Academy of Agricultural Sciences, Nanjing 210014,
China
- School of Food, Henan Institute of Science and Technology, Xinxiang 453003,
China
| | - Alireza Ghassempour
- Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Tehran 19835-389,
Iran
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12
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Ehgartner D, Herwig C, Neutsch L. At-line determination of spore inoculum quality in Penicillium chrysogenum bioprocesses. Appl Microbiol Biotechnol 2016; 100:5363-73. [DOI: 10.1007/s00253-016-7319-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 01/11/2016] [Accepted: 01/13/2016] [Indexed: 11/30/2022]
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13
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Batista AB, Oliveira JTA, Gifoni JM, Pereira ML, Almeida MGG, Gomes VM, Da Cunha M, Ribeiro SFF, Dias GB, Beltramini LM, Lopes JLS, Grangeiro TB, Vasconcelos IM. New insights into the structure and mode of action of Mo-CBP3, an antifungal chitin-binding protein of Moringa oleifera seeds. PLoS One 2014; 9:e111427. [PMID: 25347074 PMCID: PMC4210214 DOI: 10.1371/journal.pone.0111427] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 09/27/2014] [Indexed: 11/18/2022] Open
Abstract
Mo-CBP3 is a chitin-binding protein purified from Moringa oleifera Lam. seeds that displays inhibitory activity against phytopathogenic fungi. This study investigated the structural properties and the antifungal mode of action of this protein. To this end, circular dichroism spectroscopy, antifungal assays, measurements of the production of reactive oxygen species and microscopic analyses were utilized. Mo-CBP3 is composed of 30.3% α-helices, 16.3% β-sheets, 22.3% turns and 30.4% unordered forms. The Mo-CBP3 structure is highly stable and retains its antifungal activity regardless of temperature and pH. Fusarium solani was used as a model organism for studying the mechanisms by which this protein acts as an antifungal agent. Mo-CBP3 significantly inhibited spore germination and mycelial growth at 0.05 mg.mL-1. Mo-CBP3 has both fungistatic and fungicidal effects, depending on the concentration used. Binding of Mo-CBP3 to the fungal cell surface is achieved, at least in part, via electrostatic interactions, as salt was able to reduce its inhibitory effect. Mo-CBP3 induced the production of ROS and caused disorganization of both the cytoplasm and the plasma membrane in F. solani cells. Based on its high stability and specific toxicity, with broad-spectrum efficacy against important phytopathogenic fungi at low inhibitory concentrations but not to human cells, Mo-CBP3 has great potential for the development of new antifungal drugs or transgenic crops with enhanced resistance to phytopathogens.
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Affiliation(s)
- Adelina B. Batista
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - José T. A. Oliveira
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Juliana M. Gifoni
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Mirella L. Pereira
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Marina G. G. Almeida
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Valdirene M. Gomes
- Bioscience and Biotecnology Center, State University of North Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Maura Da Cunha
- Bioscience and Biotecnology Center, State University of North Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Suzanna F. F. Ribeiro
- Bioscience and Biotecnology Center, State University of North Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Germana B. Dias
- Bioscience and Biotecnology Center, State University of North Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Leila M. Beltramini
- Physics Institute of São Carlos, University of São Paulo, São Carlos, São Paulo, Brazil
| | - José Luiz S. Lopes
- Physics Institute of São Carlos, University of São Paulo, São Carlos, São Paulo, Brazil
| | | | - Ilka M. Vasconcelos
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará, Brazil
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Sharma A, Srivastava S. Anti-Candida activity of two-peptide bacteriocins, plantaricins (Pln E/F and J/K) and their mode of action. Fungal Biol 2014; 118:264-75. [PMID: 24528647 DOI: 10.1016/j.funbio.2013.12.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 11/12/2013] [Accepted: 12/16/2013] [Indexed: 10/25/2022]
Abstract
The fungicidal effect of plantaricin peptides PlnE, -F, -J, and -K was studied against pathogenic yeast, Candida albicans. Dose-dependent inhibitory effect was observed by drop in cell viability, further demonstrated by measuring the fluorescence intensity of cells by exposing them to 5, (6)-carboxyfluorescein diacetate (CFDA). Live/dead staining by CFDA and propidium iodide (PI) also suggested the viability loss response. Also, the PI uptake by treated cells suggested the membrane damage. PlnJ was identified as most inhibitory among different plantaricins tested. PlnJ not only induced membrane potential dissipation but also resulted in the release of K(+). In addition, enhanced production of reactive oxygen species (ROS) was also observed by fluorometry using 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA). Dual staining with Hoechst stain and PI depicted both early apoptotic and necrotic cells in the treated population. Terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) positive staining further confirmed the ROS-mediated apoptosis. Scanning electron microscopy and transmission electron microscopy also revealed characteristic apoptotic features such as appearance of blebs, indentations, and wrinkling of the cell wall, discontinuity of cell membrane, undefined and damaged nuclei, and shrinkage of protoplasm. Taken together the results suggest that Pln-treatment initiate the apoptosis cell death which may lead to necrosis due to toxicity of the plantaricin peptides.
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Affiliation(s)
- Anuradha Sharma
- Department of Genetics, University of Delhi, South Campus, New Delhi 110021, India.
| | - Sheela Srivastava
- Department of Genetics, University of Delhi, South Campus, New Delhi 110021, India.
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15
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Neu TR, Lawrence JR. Investigation of microbial biofilm structure by laser scanning microscopy. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2014; 146:1-51. [PMID: 24840778 DOI: 10.1007/10_2014_272] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Microbial bioaggregates and biofilms are hydrated three-dimensional structures of cells and extracellular polymeric substances (EPS). Microbial communities associated with interfaces and the samples thereof may come from natural, technical, and medical habitats. For imaging such complex microbial communities confocal laser scanning microscopy (CLSM) is the method of choice. CLSM allows flexible mounting and noninvasive three-dimensional sectioning of hydrated, living, as well as fixed samples. For this purpose a broad range of objective lenses is available having different working distance and resolution. By means of CLSM the signals detected may originate from reflection, autofluorescence, reporter genes/fluorescence proteins, fluorochromes binding to specific targets, or other probes conjugated with fluorochromes. Recorded datasets can be used not only for visualization but also for semiquantitative analysis. As a result CLSM represents a very useful tool for imaging of microbiological samples in combination with other analytical techniques.
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Affiliation(s)
- Thomas R Neu
- Department of River Ecology, Helmholtz Centre for Environmental Research-UFZ, Brueckstrasse 3a, 39114, Magdeburg, Germany,
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16
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da Silva Pedrini MR, Dupont S, de Anchieta Câmara A, Beney L, Gervais P. Osmoporation: a simple way to internalize hydrophilic molecules into yeast. Appl Microbiol Biotechnol 2013; 98:1271-80. [PMID: 24318006 DOI: 10.1007/s00253-013-5386-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 10/29/2013] [Accepted: 11/04/2013] [Indexed: 02/04/2023]
Abstract
Internalization of hydrophilic molecules into yeast cytosol is required for different applications such as cell transformation or preservation of water soluble components by bioencapsulation. However, these molecules are not able to cross the plasma membrane and strategies have to be developed. Recent works revealed that osmotic perturbations could induce non-lethal transient permeabilization of the plasma membrane. In this work, we endeavored to clarify the phenomenon of permeabilization during rehydration after a mild hyperosmotic perturbation in order to evaluate the possibility of hydrophilic molecule internalization in yeast by this treatment. Rehydration step is particularly interesting because the large entry of water into the cells could help the internalization of molecules. The internalization of a fluorescent molecule [fluorescein isothiocyanate Dextran (FITC-Dextran), 20 kDa], added during the rehydration after a sublethal hyperosmotic treatment, was studied in Saccharomyces cerevisiae yeast cells. The internalization kinetic and the localization of the fluorescent molecules were studied by flow cytometry and fluorescence confocal microscopy. Our results show that the rehydration leads to the rapid internalization of FITC-Dextran due to a transient plasma membrane permeabilization. Thus, osmoporation, i.e. plasma membrane poration by modifications of osmotic pressure of the extracellular medium, could be a new and simple way to deliver molecules of particular interest into yeasts.
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Affiliation(s)
- Marcia Regina da Silva Pedrini
- UMR Procédés Alimentaires et Microbiologiques, Université de Bourgogne/AgroSup Dijon, 1, esplanade Erasme, 21000, Dijon, France
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17
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Oh SH, Kim JH, Kim JM, Lee JH. Asymmetrically porous PLGA/Pluronic F127 membrane for effective guided bone regeneration. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 17:1375-87. [PMID: 17260509 DOI: 10.1163/156856206778937253] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Porous guided bone regeneration (GBR) membranes with selective permeability, hydrophilicity and adhesiveness to bone were prepared with PLGA and Pluronic F127 using an immersion precipitation method. The porous PLGA/Pluronic F127 membranes were fabricated by immersing the PLGA/Pluronic F127 mixture solution (in tetraglycol) in a mold into water. The PLGA/Pluronic F127 mixture was precipitated in water by the diffusion of water into PLGA/Pluronic F127 mixture solution. It was observed that the membrane has an asymmetric column-shape porous structure. The top surface of the membrane (water contact side) had nano-size pores (approx. 50 nm) which can effectively prevent from fibrous connective tissue invasion but permeate nutrients, while the bottom surface (mold contact size) had micro-size pores (approx. 40 microm) which can improve adhesiveness with bone. From the investigations of mechanical property, water absorbability, model nutrient permeability and preliminary in vivo bone regeneration, the hydrophilized porous PLGA/F127 (5 wt%) membrane seems to be a good candidate as a GBR membrane for the effective permeation of nutrients and osteoconductivity, as well as good mechanical strength to maintain a secluded space for bone regeneration.
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Affiliation(s)
- Se Heang Oh
- Department of Advanced Materials, Hannam University, 133 Ojeong Dong, Daedeog Gu, Daejeon 306-791, South Korea
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Petkovic M, Hartmann DO, Adamová G, Seddon KR, Rebelo LPN, Pereira CS. Unravelling the mechanism of toxicity of alkyltributylphosphonium chlorides in Aspergillus nidulans conidia. NEW J CHEM 2012. [DOI: 10.1039/c1nj20470j] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Tsui CK, Woodhall J, Chen W, Lévesque CA, Lau A, Schoen CD, Baschien C, Najafzadeh MJ, de Hoog GS. Molecular techniques for pathogen identification and fungus detection in the environment. IMA Fungus 2011; 2:177-89. [PMID: 22679603 PMCID: PMC3359816 DOI: 10.5598/imafungus.2011.02.02.09] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 11/03/2011] [Indexed: 12/25/2022] Open
Abstract
Many species of fungi can cause disease in plants, animals and humans. Accurate and robust detection and quantification of fungi is essential for diagnosis, modeling and surveillance. Also direct detection of fungi enables a deeper understanding of natural microbial communities, particularly as a great many fungi are difficult or impossible to cultivate. In the last decade, effective amplification platforms, probe development and various quantitative PCR technologies have revolutionized research on fungal detection and identification. Examples of the latest technology in fungal detection and differentiation are discussed here.
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Affiliation(s)
- Clement K.M. Tsui
- Department of Forest Sciences, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - James Woodhall
- The Food and Environment Research Agency, Sand Hutton, York YO41 1LZ, UK
| | - Wen Chen
- Central Experimental Farm, Agriculture and Agri-Food Canada, Ottawa, Canada, K1A OC6
| | - C. André Lévesque
- Central Experimental Farm, Agriculture and Agri-Food Canada, Ottawa, Canada, K1A OC6
| | - Anna Lau
- Centre for Infectious Diseases and Microbiology and the University of Sydney, Westmead Hospital, Westmead, NSW 2145, Australia
- *Current mailing address: Department of Laboratory Medicine, 10 Center Drive, National Institutes of Health, Bethesda, MD 20892, USA
| | - Cor D. Schoen
- Plant Research International, Business Unit Bio-Interactions and Plant Health, PO Box 16, 6700 AA, Wageningen, The Netherlands
| | - Christiane Baschien
- Technische Universität Berlin, Environmental Microbiology, Sekr. FR1-2, Franklinstrasse 29, 10587 Berlin, Germany
- **Current mailing address: Federal Environment Agency Germany, Corrensplatz 1, 14195 Berlin, Germany
| | - Mohammad J. Najafzadeh
- CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Department of Parasitology and Mycology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - G. Sybren de Hoog
- CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
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Li X, Yu HY, Lin YF, Teng HM, Du L, Ma GG. Morphological changes of Fusarium oxysporum induced by CF66I, an antifungal compound from Burkholderia cepacia. Biotechnol Lett 2010; 32:1487-95. [DOI: 10.1007/s10529-010-0316-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Accepted: 05/11/2010] [Indexed: 11/28/2022]
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Weaver L, Michels HT, Keevil CW. Potential for preventing spread of fungi in air-conditioning systems constructed using copper instead of aluminium. Lett Appl Microbiol 2010; 50:18-23. [PMID: 19943884 DOI: 10.1111/j.1472-765x.2009.02753.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
AIMS As copper has been previously suggested as an antimicrobial surface, we tested the effectiveness of copper as an antifungal surface which could be used in air-conditioning systems as an alternative to aluminium. METHODS AND RESULTS Coupons of copper (C11000) and aluminium were inoculated with fungal isolates (Aspergillus spp., Fusarium spp., Penicillium chrysogenum and Candida albicans) for various time periods. Culture on potato dextrose agar and an in situ viability assay using the fluorochrome FUN-1 were used to determine whether spores had survived. The results showed increased die off of fungal isolates tested compared to aluminium. In addition, copper also prevented the germination of spores present, thereby reducing the risk of the release of spores. CONCLUSIONS Copper offered an antifungal surface and prevented subsequent germination of spores present. FUN-1 demonstrated that fungal spores entered into a viable but not culturable (VBNC) state on copper indicating the importance of using such methods when assessing the effect of an antifungal as culture alone may give false results. SIGNIFICANCE AND IMPACT OF STUDY Copper offers a valuable alternative to aluminium which could be used in air-conditioning systems in buildings, particularly in hospital environments where patients are more susceptible to fungal infections.
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Affiliation(s)
- L Weaver
- Environmental Healthcare Unit, University of Southampton, Biomedical Sciences Building, Bassett Crescent East, Southampton, UK.
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McNamee C, Noci F, Cronin D, Lyng J, Morgan D, Scannell A. PEF based hurdle strategy to control Pichia fermentans, Listeria innocua and Escherichia coli k12 in orange juice. Int J Food Microbiol 2010; 138:13-8. [DOI: 10.1016/j.ijfoodmicro.2009.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 11/25/2009] [Accepted: 12/02/2009] [Indexed: 10/20/2022]
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Villena GK, Fujikawa T, Tsuyumu S, Gutiérrez-Correa M. Structural analysis of biofilms and pellets of Aspergillus niger by confocal laser scanning microscopy and cryo scanning electron microscopy. BIORESOURCE TECHNOLOGY 2010; 101:1920-1926. [PMID: 19919894 DOI: 10.1016/j.biortech.2009.10.036] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 10/08/2009] [Accepted: 10/10/2009] [Indexed: 05/28/2023]
Abstract
Biomass organization of Aspergillus niger biofilms and pellets stained with fluorescein isothiocyanate were analyzed by means of confocal laser scanning microscopy and detectable differences between both types of growth were found. Three-dimensional surface plot analysis of biofilm structure revealed interstitial voids and vertical growth compared with pellets. Growth was lower in biofilm and according to fluorescence profile obtained, biomass density increased at the surface (0-20 microm). However, a decrease in fluorescence intensity was observed through optical sections of pellets even though growth was significantly higher than biofilms. Cryo scanning electron microscopy also showed structural differences. While biofilms showed a spatially ordered mycelium and well structured hyphal channels, pellets were characterized by an entangled and notoriously compacted mycelium. These findings revealed common structural characteristics between A. niger biofilms and those found in other microbial biofilms. Thus, biofilm microstructure may represent a key determinant of biofilm growth and physiology of filamentous fungi.
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Affiliation(s)
- G K Villena
- Laboratorio de Micología y Biotecnología, Universidad Nacional Agraria La Molina, Apartado 456 Lima 1, Peru
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In situ detection of freshwater fungi in an alpine stream by new taxon-specific fluorescence in situ hybridization probes. Appl Environ Microbiol 2008; 74:6427-36. [PMID: 18776035 DOI: 10.1128/aem.00815-08] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
New rRNA-targeting oligonucleotide probes permitted the fluorescence in situ hybridization (FISH) identification of freshwater fungi in an Austrian second-order alpine stream. Based on computer-assisted comparative sequence analysis, nine taxon-specific probes were designed and evaluated by whole-fungus hybridizations. Oligonucleotide probe MY1574, specific for a wide range of Eumycota, and the genus (Tetracladium)-specific probe TCLAD1395, as well as the species-specific probes ALacumi1698 (Alatospora acuminata), TRIang322 (Tricladium angulatum), and Alongi340 (Anguillospora longissima), are targeted against 18S rRNA, whereas probes TmarchB10, TmarchC1_1, TmarchC1_2, and AlongiB16 are targeted against the 28S rRNA of Tetracladium marchalianum and Anguillospora longissima, respectively. After 2 weeks and 3 months of exposure of polyethylene slides in the stream, attached germinating conidia and growing hyphae of freshwater fungi were accessible for FISH. Growing hyphae and germinating conidia on leaves and in membrane cages were also visualized by the new FISH probes.
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Van Leeuwen M, Smant W, de Boer W, Dijksterhuis J. Filipin is a reliable in situ marker of ergosterol in the plasma membrane of germinating conidia (spores) of Penicillium discolor and stains intensively at the site of germ tube formation. J Microbiol Methods 2008; 74:64-73. [DOI: 10.1016/j.mimet.2008.04.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 04/02/2008] [Accepted: 04/02/2008] [Indexed: 10/22/2022]
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Cao‐Hoang L, Marechal P, Lê‐Thanh M, Gervais P, Waché Y. Fluorescent probes to evaluate the physiological state and activity of microbial biocatalysts: A guide for prokaryotic and eukaryotic investigation. Biotechnol J 2008; 3:890-903. [DOI: 10.1002/biot.200700206] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Villena GK, Gutiérrez-Correa M. Morphological patterns of Aspergillus niger biofilms and pellets related to lignocellulolytic enzyme productivities. Lett Appl Microbiol 2007; 45:231-7. [PMID: 17718832 DOI: 10.1111/j.1472-765x.2007.02183.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To study the morphological patterns of Aspergillus niger during biofilm formation on polyester cloth by using cryo-scanning electron microscopy related to lignocellulolytic enzyme productivity. METHODS AND RESULTS Biofilm and pellet samples obtained from flask cultures were examined at -80 degrees C in a LEO PV scanning electron microscope. Spore adhesion depends on both its rough surface and adhesive substances that form a pad between spore and support. An extracellular matrix surrounding germ tubes and hyphae was also seen. Biofilm mycelia showed an orderly distribution forming surface and inner channels, while pellets showed highly intertwined superficial hyphae and a densely packed deep mycelium. Morphological differences between both types of culture correlated with differences in enzyme volumetric and specific productivities. Biofilm cultures produced higher filter paper cellulase, endoglucanase, beta-glucosidase and xylanase volumetric and specific productivities than submerged cultures. CONCLUSIONS Fungal biofilms are morphologically efficient systems for enzyme production. Favourable physiological aspects are shared with solid state fermentation, but fungal biofilms present better possibilities for process control and scale-up. SIGNIFICANCE AND IMPACT OF THE STUDY The results of this study support the importance of morphology in the productivity of fungal submerged processes, placing biofilms in a preferential category.
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Affiliation(s)
- G K Villena
- Laboratorio de Micología y Biotecnología, Universidad Nacional Agraria La Molina, Lima, Peru
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Gangwar M, Cole R, Ramani R, Sheehan DJ, Chaturvedi V. Application of fluorescent probes to study structural changes in Aspergillus fumigatus exposed to amphotericin B, itraconazole, and voriconazole. Mycopathologia 2006; 162:103-9. [PMID: 16897588 DOI: 10.1007/s11046-006-0040-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Accepted: 06/20/2006] [Indexed: 10/24/2022]
Abstract
The broad objective of this study was to document patterns of structural changes following antifungal treatment, and to determine any relationship with minimum inhibitory concentration (MIC) of an antifungal. Three clinical isolates of Aspergillus fumigatus, with high, intermediate, and low amphotericin B (AB), itraconazole (IZ), and voriconazole (VZ) MICs were studied in 24-well plates with cover slips. The fluorescent probes used were Calcofluor White (cell wall), propidium iodide (nucleus), and MitoTracker Green FM (mitochondria). Fluorescent microscopy as early as 3-h after exposure revealed that AB treated hyphae had intact cell wall with deformed mitochondria and nuclei while IZ and VZ treated hyphae revealed no intact cell wall, and deformation of mitochondria and nuclei. At 48 h, AB treated cells revealed rupture of hyphae and disintegration of mitochondria, and nuclei, IZ treated hyphae were swollen with disintegration of mitochondria, and nuclei while VZ treated hyphae showed rupture and disintegration of mitochondria and nuclei. The structural changes for the three strains studied were similar in fluorescent microscopy as long as the incubation time and their respective MICs were used. Thus, AB, IZ, and VZ induced gross organelle defects in A. fumigatus nuclei, mitochondria, and cell wall, which were consistent with respective MICs of antifungals used.
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Affiliation(s)
- Madhurama Gangwar
- Mycology Laboratory, Wadsworth Center, NYSDOH, 120 New Scotland Ave., Albany, NY 12208 - 2002, USA
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Chitarra GS, Abee T, Rombouts FM, Dijksterhuis J. 1-Octen-3-ol inhibits conidia germination of Penicillium paneum despite of mild effects on membrane permeability, respiration, intracellular pH, and changes the protein composition. FEMS Microbiol Ecol 2005; 54:67-75. [PMID: 16329973 DOI: 10.1016/j.femsec.2005.02.013] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2004] [Revised: 01/21/2005] [Accepted: 02/28/2005] [Indexed: 11/17/2022] Open
Abstract
1-Octen-3-ol is a volatile germination self-inhibitor produced by Penicillium paneum that blocks the germination process. The size of conidia treated with 1-octen-3-ol was similar to that of freshly harvested conidia. Exposure to 1-octen-3-ol resulted in staining of 10-20% of the conidia with PI and TOTO, fluorescent DNA probes that cannot enter cells with an intact membrane, whereas only 3-5% of non-treated conidia were stained. Addition of 1-octen-3-ol to germinating conidia resulted in transient dissipation of the pH gradient. From this, we conclude that slight permeabilisation of the fungal membrane occurs in the presence of the inhibitor. Two-dimensional gel electrophoresis analysis of protein patterns revealed striking differences between non-germinated conidia, germinated conidia and 1-octen-3-ol-treated conidia. In conclusion, 1-octen-3-ol has mild effects on the plasma membrane, but interferes with essential metabolic processes, such as swelling and germination of the conidia, but in a reversible manner.
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Affiliation(s)
- Gilma S Chitarra
- Laboratory of Food Microbiology, Wageningen University, Biotechnion, The Netherlands
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Peter J, Armstrong D, Lyman CA, Walsh TJ. Use of fluorescent probes to determine MICs of amphotericin B and caspofungin against Candida spp. and Aspergillus spp. J Clin Microbiol 2005; 43:3788-92. [PMID: 16081911 PMCID: PMC1233965 DOI: 10.1128/jcm.43.8.3788-3792.2005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We investigated the utility of mechanism-based fluorescent probes for determination of MICs (FMICs) of amphotericin B and caspofungin against Candida spp. and Aspergillus spp. Amphotericin B was selected as a membrane-active antifungal agent, and caspofungin was selected as a cell wall-active agent. FMICs were also compared to the MIC determined by CLSI (formerly NCCLS) methods. Five isolates per species of Candida albicans, Candida glabrata, Candida parapsilosis, Aspergillus fumigatus, and Aspergillus terreus were studied with either amphotericin B or caspofungin. The fluorescent probes, carboxyfluorescein diacetate (CFDA) for cytoplasmic esterase activity and dihexyloxacarbocyanine iodide (DiOC6) for cell membrane potential, were each added to their respective plates. MICs and FMICs were determined in at least three separate experiments (in duplicate). Fluorescence was measured using a 96-well plate fluorometer. For amphotericin B and caspofungin, the FMIC end point was the lowest concentration of drug at which the percent growth inhibition from treated organisms versus control organisms displayed 80% inhibition for amphotericin B and 50% inhibition for caspofungin as measured by a fluorescent signal. The MIC for amphotericin B was defined as the lowest concentration of antifungal displaying no visible growth for both Aspergillus and Candida spp. The MIC for caspofungin was the lowest concentration of drug that displayed a minimum effective concentration for Aspergillus spp. For Candida spp., the MIC for caspofungin was defined as the concentration at which the antifungal agent significantly inhibits the organism. The FMICs of both antifungals, as measured by the DiOC6 membrane probe, showed good agreement (83% to 100%), within one well dilution, with the MICs against amphotericin B and caspofungin for all species. Also, the FMICs measured by the CFDA cytoplasmic esterase probe reflecting damage due to cell wall or cell membrane showed strong agreement (79 to 100%) with the MICs of both amphotericin B and caspofungin for all species. There was no significant difference in comparisons of MIC and FMIC values (P > or = 0.05). The use of fluorescent probes provides a mechanism-based method of determination of MICs of amphotericin B and caspofungin against Candida spp. and Aspergillus spp. that correlates well with standard methods.
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Affiliation(s)
- Joanne Peter
- Immunocompromised Host Section, National Cancer Institute, Bethesda, Maryland
| | - Derek Armstrong
- Immunocompromised Host Section, National Cancer Institute, Bethesda, Maryland
| | - Caron A. Lyman
- Immunocompromised Host Section, National Cancer Institute, Bethesda, Maryland
| | - Thomas J. Walsh
- Immunocompromised Host Section, National Cancer Institute, Bethesda, Maryland
- Corresponding author. Mailing address: Immunocompromised Host Section, Pediatric Oncology Branch, National Cancer Institute, Building 10, Room 13N240, 10 Center Drive, Bethesda, MD 20892-1928. Phone: (301) 496-7103. Fax: (301) 480-2308. E-mail:
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Czymmek K. Exploring Fungal Activity with Confocal and Multiphoton Microscopy. Mycology 2005. [DOI: 10.1201/9781420027891.ch15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Trevors JT. Fluorescent probes for bacterial cytoplasmic membrane research. JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS 2003; 57:87-103. [PMID: 12915003 DOI: 10.1016/s0165-022x(03)00076-9] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Fluorescent methods in biological and medical research are extremely useful at the cellular and molecular levels. This is due to sensitive and affordable detection equipment and a variety of specific and more general fluorescent probes, and analytical procedures. In this article, I examine the use of fluorescence membrane probes to study the fluidity (membrane polarization) of the bacterial cytoplasmic membrane, central to energy transduction, ion and nutrient transport and diffusion of water and gases.
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Affiliation(s)
- J T Trevors
- Department of Environmental Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
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Chitarra GS, Breeuwer P, Nout MJR, van Aelst AC, Rombouts FM, Abee T. An antifungal compound produced by Bacillus subtilis YM 10-20 inhibits germination of Penicillium roqueforti conidiospores. J Appl Microbiol 2003; 94:159-66. [PMID: 12534806 DOI: 10.1046/j.1365-2672.2003.01819.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To identify and characterize an antifungal compound produced by Bacillus subtilis YM 10-20 which prevents spore germination of Penicillium roqueforti. METHODS AND RESULTS The antifungal compound was isolated by acid precipitation with HCl. This compound inhibited fungal germination and growth. Identification by HPLC and mass spectrometry analysis showed high similarity to iturin A. Permeabilization and morphological changes in P. roqueforti conidia in the presence of the inhibitor were revealed by fluorescence staining and SEM, respectively. CONCLUSOINS: The iturin-like compound produced by B. subtilis YM 10-20 permeabilizes fungal spores and blocks germination. SIGNIFICANCE AND IMPACT OF THE STUDY Fluorescence staining in combination with flow cytometry and scanning electron microscopy are efficient tools for assessing the action of antifungal compounds against spores. Iturin-like compounds may permeabilize fungal spores and inhibit their germination.
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Affiliation(s)
- G S Chitarra
- Department of Agrotechnology and Food Sciences, Laboratory of Food Microbiology, Wageningen University, The Netherlands
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Lass-Flörl C, Nagl M, Speth C, Ulmer H, Dierich MP, Würzner R. Studies of in vitro activities of voriconazole and itraconazole against Aspergillus hyphae using viability staining. Antimicrob Agents Chemother 2001; 45:124-8. [PMID: 11120954 PMCID: PMC90249 DOI: 10.1128/aac.45.1.124-128.2001] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The minimal fungicidal concentrations (MFCs) of voriconazole and itraconazole for five clinical isolates each of Aspergillus terreus, Aspergillus fumigatus, Aspergillus flavus, and Aspergillus niger were determined by a broth macrodilution method. Conidial suspensions as inocula were compared to hyphae as inocula since the invasive form of aspergillosis is manifested by the appearance of hyphal structures. In addition, cell viability staining with the dye FUN-1 was performed to assess time-dependent damage of hyphae exposed to various concentrations of the antifungal agents. With conidial inocula the MFC ranges of voriconazole were 0.5 to 4 microg/ml and those of itraconazole were 0.25 to 2 microg/ml, whereas the MFCs (2 to >16 microg/ml) with hyphal inocula were substantially higher (P < 0.01) for both itraconazole and voriconazole. Only minor differences between the tested antifungals were observed since 16 of 20 and 17 of 20 of the isolates of Aspergillus spp. tested appeared to be killed by voriconazole and itraconazole, respectively. The results of FUN-1 viability staining correlated closely to colony counts, but various time- and dose-dependent levels of viability of hyphae were also observed. In conclusion, our study demonstrates the importance of the type of inoculum used to test antifungals and the applicability of FUN-1 staining as a rapid and sensitive method for assaying the viability of hyphae.
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Affiliation(s)
- C Lass-Flörl
- Department of Hygiene and Social Medicine, University of Innsbruck, Innsbruck, Austria.
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Cox SD, Mann CM, Markham JL, Bell HC, Gustafson JE, Warmington JR, Wyllie SG. The mode of antimicrobial action of the essential oil of Melaleuca alternifolia (tea tree oil). J Appl Microbiol 2000; 88:170-5. [PMID: 10735256 DOI: 10.1046/j.1365-2672.2000.00943.x] [Citation(s) in RCA: 512] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The essential oil of Melaleuca alternifolia (tea tree) exhibits broad-spectrum antimicrobial activity. Its mode of action against the Gram-negative bacterium Escherichia coli AG100, the Gram-positive bacterium Staphylococcus aureus NCTC 8325, and the yeast Candida albicans has been investigated using a range of methods. We report that exposing these organisms to minimum inhibitory and minimum bactericidal/fungicidal concentrations of tea tree oil inhibited respiration and increased the permeability of bacterial cytoplasmic and yeast plasma membranes as indicated by uptake of propidium iodide. In the case of E. coli and Staph. aureus, tea tree oil also caused potassium ion leakage. Differences in the susceptibility of the test organisms to tea tree oil were also observed and these are interpreted in terms of variations in the rate of monoterpene penetration through cell wall and cell membrane structures. The ability of tea tree oil to disrupt the permeability barrier of cell membrane structures and the accompanying loss of chemiosmotic control is the most likely source of its lethal action at minimum inhibitory levels.
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Affiliation(s)
- S D Cox
- Centre for Biostructural and Biomolecular Research, University of Western Sydney, Hawkesbury, New South Wales, Western Australia.
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Brul S, Klis FM. Mechanistic and mathematical inactivation studies of food spoilage fungi. Fungal Genet Biol 1999; 27:199-208. [PMID: 10441445 DOI: 10.1006/fgbi.1999.1149] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fungal spoilage forms an increasing economic problem in the food industry. Chemical antifungals are becoming less attractive as food preservatives and hygiene agents due to the development of resistance and due to stricter legal regulations concerning the permitted concentrations. Finally, consumers tend to demand more "naturally preserved" or preservative-free products. Here we review our understanding of the mechanisms of action and resistance to classical antifungals. Next, we evaluate the scientific basis underlying the application of novel, natural antifungals. Finally, we discuss the mathematical modelling of fungal growth and the development of preliminary predictive lag-time models. The eventual aim of the reviewed work is to generate mathematical lag-time models in real foods that predict the microbiological stability of the food and are based on a mechanistic understanding of the chain of events that leads to cell death, or an extension of lag-time of the initiation of outgrowth.
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Affiliation(s)
- S Brul
- Unilever Research Division, Vlaardingen, 3130 AC, The Netherlands
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Cai YJ, Chapman SJ, Buswell JA, Chang ST. Production and distribution of endoglucanase, cellobiohydrolase, and beta-glucosidase components of the cellulolytic system of Volvariella volvacea, the edible straw mushroom. Appl Environ Microbiol 1999; 65:553-9. [PMID: 9925582 PMCID: PMC91061 DOI: 10.1128/aem.65.2.553-559.1999] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/1998] [Accepted: 10/27/1998] [Indexed: 11/20/2022] Open
Abstract
The edible straw mushroom, Volvariella volvacea, produces a multicomponent enzyme system consisting of endo-1,4-beta-glucanase, cellobiohydrolase, and beta-glucosidase for the conversion of cellulose to glucose. The highest levels of endoglucanase and cellobiohydrolase were recorded in cultures containing microcrystalline cellulose (Avicel) or filter paper, while lower but detectable levels of activity were also produced on carboxymethyl cellulose, cotton wool, xylitol, or salicin. Biochemical analyses of different culture fractions in cultures exhibiting peak enzyme production revealed that most of the endoglucase was present either in the culture filtrate (45.8% of the total) or associated with the insoluble pellet fraction remaining after centrifugation of homogenized mycelia (32.6%). Cellobiohydrolase exhibited a similar distribution pattern, with 58.9% of the total enzyme present in culture filtrates and 31.0% associated with the pellet fraction. Conversely, most beta-glucosidase activity (63.9% of the total) was present in extracts of fungal mycelia whereas only 9.4% was detected in culture filtrates. The endoglucanase and beta-glucosidase distribution patterns were confirmed by confocal laser scanning microscopy combined with immunolabelling. Endoglucanase was shown to be largely cell wall associated or located extracellularly, with the highest concentrations being present in a region 1 to 2 microm wide immediately adjacent to the outer surface of (and possibly including) the hyphal wall and extending 60 to 70 microm from the hyphal tip. Immunofluorescence patterns indicated little if any intracellular endoglucanase. Most beta-glucosidase was located intracellularly in the apical area extending 60 to 70 microm below the hyphal tip, although enzyme was also evident in the extracellular region extending approximately 15 microm all around the hyphal tip and trailing back along the length of the hypha. The regions of the hypha located some distance from the apical region appeared to be devoid of intracellular beta-glucosidase, and the enzyme appears to be associated almost exclusively with, or located on the outside surface of, the hyphal wall.
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Affiliation(s)
- Y J Cai
- Department of Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
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Dielbandhoesing SK, Zhang H, Caro LH, van der Vaart JM, Klis FM, Verrips CT, Brul S. Specific cell wall proteins confer resistance to nisin upon yeast cells. Appl Environ Microbiol 1998; 64:4047-52. [PMID: 9758839 PMCID: PMC106598 DOI: 10.1128/aem.64.10.4047-4052.1998] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cell wall of a yeast cell forms a barrier for various proteinaceous and nonproteinaceous molecules. Nisin, a small polypeptide and a well-known preservative active against gram-positive bacteria, was tested with wild-type Saccharomyces cerevisiae. This peptide had no effect on intact cells. However, removal of the cell wall facilitated access of nisin to the membrane and led to cell rupture. The roles of individual components of the cell wall in protection against nisin were studied by using synchronized cultures. Variation in nisin sensitivity was observed during the cell cycle. In the S phase, which is the phase in the cell cycle in which the permeability of the yeast wall to fluorescein isothiocyanate dextrans is highest, the cells were most sensitive to nisin. In contrast, the cells were most resistant to nisin after a peak in expression of the mRNA of cell wall protein 2 (Cwp2p), which coincided with the G2 phase of the cell cycle. A mutant lacking Cwp2p has been shown to be more sensitive to cell wall-interfering compounds and Zymolyase (J. M. Van der Vaart, L. H. Caro, J. W. Chapman, F. M. Klis, and C. T. Verrips, J. Bacteriol. 177:3104-3110, 1995). Here we show that of the single cell wall protein knockouts, a Cwp2p-deficient mutant is most sensitive to nisin. A mutant with a double knockout of Cwp1p and Cwp2p is hypersensitive to the peptide. Finally, in yeast mutants with impaired cell wall structure, expression of both CWP1 and CWP2 was modified. We concluded that Cwp2p plays a prominent role in protection of cells against antimicrobial peptides, such as nisin, and that Cwp1p and Cwp2p play a key role in the formation of a normal cell wall.
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Affiliation(s)
- S K Dielbandhoesing
- Unilever Research Laboratorium Vlaardingen, 3133 AT Vlaardingen, The Netherlands
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Determination of the intracellular pH (pHi) of growing cells of Saccharomyces cerevisiae: the effect of reduced-expression of the membrane H+-ATPase. J Microbiol Methods 1998. [DOI: 10.1016/s0167-7012(97)00095-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Cuppers HG, Oomes S, Brul S. A model for the combined effects of temperature and salt concentration on growth rate of food spoilage molds. Appl Environ Microbiol 1997; 63:3764-9. [PMID: 9327540 PMCID: PMC168685 DOI: 10.1128/aem.63.10.3764-3769.1997] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We modeled mold growth on a solid culture medium at various temperatures and NaCl concentrations by using five common food spoilage molds (Penicillium roqueforti, Trichoderma harzianum, Paecilomyces variotii, Aspergillus niger, and Emericella nidulans). For the description of the growth rate (expressed as the increase in colony diameter per unit of time) as a function of temperature and NaCl concentration, a six-parameter model has been developed. The model combines either the Rosso-type or the Ratkowsky-type temperature dependence with the NaCl concentration dependence derived from the relationship between the growth rate and square root of (1 - water activity), as proposed by Gibson and coworkers (A. M. Gibson, J. Baranyi, J. I. Pitt, M. J. Eyles, and T. A. Roberts, Int. J. Food Microbiol. 23:419-431, 1994). The model will be of use to food microbiologists whose aim is to predict the likelihood of fungal spoilage.
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Affiliation(s)
- H G Cuppers
- Unilever Research Laboratorium Vlaardingen, The Netherlands.
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