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Tamminen A, Happonen P, Barth D, Holmström S, Wiebe MG. High throughput, small scale methods to characterise the growth of marine fungi. PLoS One 2020; 15:e0236822. [PMID: 32764772 PMCID: PMC7413501 DOI: 10.1371/journal.pone.0236822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 07/14/2020] [Indexed: 11/26/2022] Open
Abstract
Various marine fungi have been shown to produce interesting, bioactive compounds, but scaling up the production of these compounds can be challenging, particularly because little is generally known about how the producing organisms grow. Here we assessed the suitability of using 100-well BioScreen plates or 96-well plates incubated in a robot hotel to cultivate eight filamentous marine fungi, six sporulating and two non-sporulating, to obtain data on growth and substrate (glucose, xylose, galactose or glycerol) utilisation in a high throughput manner. All eight fungi grew in both cultivation systems, but growth was more variable and with more noise in the data in the Cytomat plate hotel than in the BioScreen. Specific growth rates between 0.01 (no added substrate) and 0.07 h-1 were measured for strains growing in the BioScreen and between 0.01 and 0.27 h-1 for strains in the plate hotel. Three strains, Dendryphiella salina LF304, Penicillium chrysogenum KF657 and Penicillium pinophilum LF458, consistently had higher specific growth rates on glucose and xylose in the plate hotel than in the BioScreen, but otherwise results were similar in the two systems. However, because of the noise in data from the plate hotel, the data obtained from it could only be used to distinguish between substrates which did or did not support growth, whereas data from BioScreen also provided information on substrate preference. Glucose was the preferred substrate for all strains, followed by xylose and galactose. Five strains also grew on glycerol. Therefore it was important to minimise the amount of glycerol introduced with the inoculum to avoid misinterpreting the results for growth on poor substrates. We concluded that both systems could provide physiological data with filamentous fungi, provided sufficient replicates are included in the measurements.
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Affiliation(s)
- Anu Tamminen
- VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Petrus Happonen
- VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Dorothee Barth
- VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Sami Holmström
- VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Marilyn G. Wiebe
- VTT Technical Research Centre of Finland Ltd, Espoo, Finland
- * E-mail:
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García-Díaz M, Gil-Serna J, Patiño B, García-Cela E, Magan N, Medina Á. Assessment of the Effect of Satureja montana and Origanum virens Essential Oils on Aspergillus flavus Growth and Aflatoxin Production at Different Water Activities. Toxins (Basel) 2020; 12:toxins12030142. [PMID: 32106532 PMCID: PMC7150974 DOI: 10.3390/toxins12030142] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 02/19/2020] [Accepted: 02/22/2020] [Indexed: 02/08/2023] Open
Abstract
Aflatoxin contamination of foodstuffs poses a serious risk to food security, and it is essential to search for new control methods to prevent these toxins entering the food chain. Several essential oils are able to reduce the growth and mycotoxin biosynthesis of toxigenic species, although their efficiency is strongly influenced by the environmental conditions. In this work, the effectiveness of Satureja montana and Origanum virens essential oils to control Aspergillus flavus growth was evaluated under three water activity levels (0.94, 0.96 and 0.98 aw) using a Bioscreen C, a rapid in vitro spectrophotometric technique. The aflatoxin concentrations at all conditions tested were determined by HPLC-FLD. Aspergillus flavus growth was delayed by both essential oil treatments. However, only S. montana essential oil was able to significantly affect aflatoxin production, although the inhibition percentages widely differed among water activities. The most significant reduction was observed at 0.96 aw, which is coincident with the conditions in which A. flavus reached the highest levels of aflatoxin production. On the contrary, the treatment with S. montana essential oil was not effective in significantly reducing aflatoxin production at 0.94 aw. Therefore, it is important to study the interaction of the new control compounds with environmental factors before their application in food matrices, and in vitro ecophysiological studies are a good option since they provide accurate and rapid results.
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Affiliation(s)
- Marta García-Díaz
- Department of Genetics, Physiology, and Microbiology, Faculty of Biology, University Complutense of Madrid, Jose Antonio Novais 12, 28040 Madrid, Spain; (M.G.-D.); (B.P.)
| | - Jessica Gil-Serna
- Department of Genetics, Physiology, and Microbiology, Faculty of Biology, University Complutense of Madrid, Jose Antonio Novais 12, 28040 Madrid, Spain; (M.G.-D.); (B.P.)
- Correspondence: (J.G.-S.); (Á.M.)
| | - Belén Patiño
- Department of Genetics, Physiology, and Microbiology, Faculty of Biology, University Complutense of Madrid, Jose Antonio Novais 12, 28040 Madrid, Spain; (M.G.-D.); (B.P.)
| | - Esther García-Cela
- Applied Mycology Group, Cranfield Soil and AgriFood Institute, Cranfield University, Bedford MK43 0AL, UK; (E.G.-C.); (N.M.)
- Biological and Environmental Sciences, School of Life and Medical Sciences, University of Hertfordshire, Hatfield AL109AB, UK
| | - Naresh Magan
- Applied Mycology Group, Cranfield Soil and AgriFood Institute, Cranfield University, Bedford MK43 0AL, UK; (E.G.-C.); (N.M.)
| | - Ángel Medina
- Applied Mycology Group, Cranfield Soil and AgriFood Institute, Cranfield University, Bedford MK43 0AL, UK; (E.G.-C.); (N.M.)
- Correspondence: (J.G.-S.); (Á.M.)
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Sheng S, Xin L, Yam JKH, Salido MM, Khong NZJ, Liu Q, Chea RA, Li HY, Yang L, Liang ZX, Xu L. The MapZ-Mediated Methylation of Chemoreceptors Contributes to Pathogenicity of Pseudomonas aeruginosa. Front Microbiol 2019; 10:67. [PMID: 30804897 PMCID: PMC6370697 DOI: 10.3389/fmicb.2019.00067] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 01/15/2019] [Indexed: 12/22/2022] Open
Abstract
The pathogenic bacterium Pseudomonas aeruginosa is notorious for causing acute and chronic infections in humans. The ability to infect host by P. aeruginosa is dependent on a complex cellular signaling network, which includes a large number of chemosensory signaling pathways that rely on the methyl-accepting chemotaxis proteins (MCPs). We previously found that the second messenger c-di-GMP-binding adaptor MapZ modulates the methylation of an amino acid-detecting MCP by directly interacting with a chemotaxis methyltransferase CheR1. The current study further expands our understanding of the role of MapZ in regulating chemosensory pathways by demonstrating that MapZ suppresses the methylation of multiple MCPs in P. aeruginosa PAO1. The MCPs under the control of MapZ include five MCPs (Aer, CtpH, CptM, PctA, and PctB) for detecting oxygen/energy, inorganic phosphate, malate and amino acids, and three MCPs (PA1251, PA1608, and PA2867) for detecting unknown chemoattractant or chemorepellent. Chemotaxis assays showed that overexpression of MapZ hampered the taxis of P. aeruginosa toward chemoattractants and scratch-wounded human cells. Mouse infection experiments demonstrated that a dysfunction in MapZ regulation had a profound negative impact on the dissemination of P. aeruginosa and resulted in attenuated bacterial virulence. Together, the results imply that by controlling the methylation of various MCPs via the adaptor protein MapZ, c-di-GMP exerts a profound influence on chemotactic responses and bacterial pathogenesis.
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Affiliation(s)
- Shuo Sheng
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Innovative and Entrepreneurial Research Team of Sociomicrobiology, South China Agricultural University, Guangzhou, China
| | - Lingyi Xin
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Joey Kuok Hoong Yam
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Singapore
| | - May Margarette Salido
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Singapore
| | - Nicole Zi Jia Khong
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Qiong Liu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Innovative and Entrepreneurial Research Team of Sociomicrobiology, South China Agricultural University, Guangzhou, China
| | - Rachel Andrea Chea
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Hoi Yeung Li
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Liang Yang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Singapore
| | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Linghui Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Innovative and Entrepreneurial Research Team of Sociomicrobiology, South China Agricultural University, Guangzhou, China
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