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Cowen D, Zhang R, Komorowski M. Infections in long-duration space missions. THE LANCET. MICROBE 2024; 5:100875. [PMID: 38861994 DOI: 10.1016/s2666-5247(24)00098-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 03/25/2024] [Accepted: 04/09/2024] [Indexed: 06/13/2024]
Abstract
As government space agencies and private companies announce plans for deep space exploration and colonisation, prioritisation of medical preparedness is becoming crucial. Among all medical conditions, infections pose one of the biggest threats to astronaut health and mission success. To gain a comprehensive understanding of these risks, we review the measured and estimated incidence of infections in space, effect of space environment on the human immune system and microbial behaviour, current preventive and management strategies for infections, and future perspectives for diagnosis and treatment. This information will enable space agencies to enhance their comprehension of the risk of infection in space, highlight gaps in knowledge, aid better crew preparation, and potentially contribute to sepsis management in terrestrial settings, including not only isolated or austere environments but also conventional clinical settings.
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Affiliation(s)
- Daniel Cowen
- School of Medicine, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK
| | | | - Matthieu Komorowski
- Department of Surgery and Cancer, Division of Anaesthetics, Pain Medicine, and Intensive Care, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK.
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2
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Verbeelen T, Fernandez CA, Nguyen TH, Gupta S, Aarts R, Tabury K, Leroy B, Wattiez R, Vlaeminck SE, Leys N, Ganigué R, Mastroleo F. Whole transcriptome analysis highlights nutrient limitation of nitrogen cycle bacteria in simulated microgravity. NPJ Microgravity 2024; 10:3. [PMID: 38200027 PMCID: PMC10781756 DOI: 10.1038/s41526-024-00345-z] [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: 09/20/2023] [Accepted: 01/01/2024] [Indexed: 01/12/2024] Open
Abstract
Regenerative life support systems (RLSS) will play a vital role in achieving self-sufficiency during long-distance space travel. Urine conversion into a liquid nitrate-based fertilizer is a key process in most RLSS. This study describes the effects of simulated microgravity (SMG) on Comamonas testosteroni, Nitrosomonas europaea, Nitrobacter winogradskyi and a tripartite culture of the three, in the context of nitrogen recovery for the Micro-Ecological Life Support System Alternative (MELiSSA). Rotary cell culture systems (RCCS) and random positioning machines (RPM) were used as SMG analogues. The transcriptional responses of the cultures were elucidated. For CO2-producing C. testosteroni and the tripartite culture, a PermaLifeTM PL-70 cell culture bag mounted on an in-house 3D-printed holder was applied to eliminate air bubble formation during SMG cultivation. Gene expression changes indicated that the fluid dynamics in SMG caused nutrient and O2 limitation. Genes involved in urea hydrolysis and nitrification were minimally affected, while denitrification-related gene expression was increased. The findings highlight potential challenges for nitrogen recovery in space.
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Affiliation(s)
- Tom Verbeelen
- Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Celia Alvarez Fernandez
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Thanh Huy Nguyen
- Department of Proteomics and Microbiology, University of Mons, Av. Du Champs de Mars 6, 7000, Mons, Belgium
| | - Surya Gupta
- Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium
| | - Raf Aarts
- Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium
| | - Kevin Tabury
- Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium
| | - Baptiste Leroy
- Department of Proteomics and Microbiology, University of Mons, Av. Du Champs de Mars 6, 7000, Mons, Belgium
| | - Ruddy Wattiez
- Department of Proteomics and Microbiology, University of Mons, Av. Du Champs de Mars 6, 7000, Mons, Belgium
| | - Siegfried E Vlaeminck
- Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium
- Centre for Advanced Process Technology for Urban REsource Recovery (CAPTURE), Frieda Saeysstraat 1, 9052, Ghent, Belgium
| | - Natalie Leys
- Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium
| | - Ramon Ganigué
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium
- Centre for Advanced Process Technology for Urban REsource Recovery (CAPTURE), Frieda Saeysstraat 1, 9052, Ghent, Belgium
| | - Felice Mastroleo
- Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium.
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3
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Espinosa-Ortiz EJ, Gerlach R, Peyton BM, Roberson L, Yeh DH. Biofilm reactors for the treatment of used water in space:potential, challenges, and future perspectives. Biofilm 2023; 6:100140. [PMID: 38078057 PMCID: PMC10704334 DOI: 10.1016/j.bioflm.2023.100140] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 06/27/2023] [Accepted: 06/27/2023] [Indexed: 02/29/2024] Open
Abstract
Water is not only essential to sustain life on Earth, but also is a crucial resource for long-duration deep space exploration and habitation. Current systems in space rely on the resupply of water from Earth, however, as missions get longer and move farther away from Earth, resupply will no longer be a sustainable option. Thus, the development of regenerative reclamation water systems through which useable water can be recovered from "waste streams" (i.e., used waters) is sorely needed to further close the loop in space life support systems. This review presents the origin and characteristics of different used waters generated in space and discusses the intrinsic challenges of developing suitable technologies to treat such streams given the unique constrains of space exploration and habitation (e.g., different gravity conditions, size and weight limitations, compatibility with other systems, etc.). In this review, we discuss the potential use of biological systems, particularly biofilms, as possible alternatives or additions to current technologies for water reclamation and waste treatment in space. The fundamentals of biofilm reactors, their advantages and disadvantages, as well as different reactor configurations and their potential for use and challenges to be incorporated in self-sustaining and regenerative life support systems in long-duration space missions are also discussed. Furthermore, we discuss the possibility to recover value-added products (e.g., biomass, nutrients, water) from used waters and the opportunity to recycle and reuse such products as resources in other life support subsystems (e.g., habitation, waste, air, etc.).
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Affiliation(s)
- Erika J. Espinosa-Ortiz
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, 59717, USA
| | - Robin Gerlach
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, 59717, USA
| | - Brent M. Peyton
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, 59717, USA
| | - Luke Roberson
- Exploration Research and Technology Directorate, NASA, Kennedy Space Center, 32899, USA
| | - Daniel H. Yeh
- Department of Civil & Environmental Engineering, University of South Florida, Tampa, FL, 33620, USA
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4
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Piscon B, Pia Esposito E, Fichtman B, Samburski G, Efremushkin L, Amselem S, Harel A, Rahav G, Zarrilli R, Gal-Mor O. The Effect of Outer Space and Other Environmental Cues on Bacterial Conjugation. Microbiol Spectr 2023; 11:e0368822. [PMID: 36995224 PMCID: PMC10269834 DOI: 10.1128/spectrum.03688-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 03/11/2023] [Indexed: 03/31/2023] Open
Abstract
Bacterial conjugation is one of the most abundant horizontal gene transfer (HGT) mechanisms, playing a fundamental role in prokaryote evolution. A better understanding of bacterial conjugation and its cross talk with the environment is needed for a more complete understanding of HGT mechanisms and to fight the dissemination of malicious genes between bacteria. Here, we studied the effect of outer space, microgravity, and additional key environmental cues on transfer (tra) gene expression and conjugation efficiency, using the under studied broad-host range plasmid pN3, as a model. High resolution scanning electron microscopy revealed the morphology of the pN3 conjugative pili and mating pair formation during conjugation. Using a nanosatellite carrying a miniaturized lab, we studied pN3 conjugation in outer space, and used qRT-PCR, Western blotting and mating assays to determine the effect of ground physicochemical parameters on tra gene expression and conjugation. We showed for the first time that bacterial conjugation can occur in outer space and on the ground, under microgravity-simulated conditions. Furthermore, we demonstrated that microgravity, liquid media, elevated temperature, nutrient depletion, high osmolarity and low oxygen significantly reduce pN3 conjugation. Interestingly, under some of these conditions we observed an inverse correlation between tra gene transcription and conjugation frequency and found that induction of at least traK and traL can negatively affect pN3 conjugation frequency in a dose-dependent manner. Collectively, these results uncover pN3 regulation by various environmental cues and highlight the diversity of conjugation systems and the different ways in which they may be regulated in response to abiotic signals. IMPORTANCE Bacterial conjugation is a highly ubiquitous and promiscuous process, by which a donor bacterium transfers a large portion of genetic material to a recipient cell. This mechanism of horizontal gene transfer plays an important role in bacterial evolution and in the ability of bacteria to acquire resistance to antimicrobial drugs and disinfectants. Bacterial conjugation is a complex and energy-consuming process, that is tightly regulated and largely affected by various environmental signals sensed by the bacterial cell. Comprehensive knowledge about bacterial conjugation and the ways it is affected by environmental cues is required to better understand bacterial ecology and evolution and to find new effective ways to counteract the threating dissemination of antibiotic resistance genes between bacterial populations. Moreover, characterizing this process under stress or suboptimal growth conditions such as elevated temperatures, high salinity or in the outer space, may provide insights relevant to future habitat environmental conditions.
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Affiliation(s)
- Bar Piscon
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel
- Department of Clinical Microbiology and Immunology, Tel Aviv University, Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eliana Pia Esposito
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Boris Fichtman
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Guy Samburski
- SpacePharma R&D Israel LTD., Herzliya Pituach, Israel & SpacePharma SA, Courgenay, Switzerland
| | - Lihi Efremushkin
- SpacePharma R&D Israel LTD., Herzliya Pituach, Israel & SpacePharma SA, Courgenay, Switzerland
| | - Shimon Amselem
- SpacePharma R&D Israel LTD., Herzliya Pituach, Israel & SpacePharma SA, Courgenay, Switzerland
| | - Amnon Harel
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Galia Rahav
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Raffaele Zarrilli
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Ohad Gal-Mor
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel
- Department of Clinical Microbiology and Immunology, Tel Aviv University, Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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5
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Wang Y, Shen W, Yin M, Huang W, Ye B, Li P, Shi S, Bai G, Guo X, Jin Y, Lin K, Zhang Y, Jiang Y, Wang J, Han Y, Zhao Z. Changes in Higher-Order Chromosomal Structure of Klebsiella pneumoniae Under Simulated Microgravity. Front Microbiol 2022; 13:879321. [PMID: 35711756 PMCID: PMC9197264 DOI: 10.3389/fmicb.2022.879321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 05/10/2022] [Indexed: 11/29/2022] Open
Abstract
Our previous work have shown that certain subpopulations of Klebsiella pneumoniae exhibit significant phenotypic changes under simulated microgravity (SMG), including enhanced biofilm formation and cellulose synthesis, which may be evoked by changes in gene expression patterns. It is well known that prokaryotic cells genomic DNA can be hierarchically organized into different higher-order three-dimensional structures, which can highly influence gene expression. It is remain elusive whether phenotypic changes induced by SMG in the subpopulations of K. pneumoniae are driven by genome higher-order structural changes. Here, we investigated the above-mentioned issue using the wild-type (WT) K. pneumoniae (WT was used as a control strain and continuously cultivated for 2 weeks under standard culture conditions of normal gravity) and two previous identified subpopulations (M1 and M2) obtained after 2 weeks of continuous incubation in a SMG device. By the combination of genome-wide chromosome conformation capture (Hi-C), RNA-seq and whole-genome methylation (WGS) analyses, we found that the along with the global chromosome interactions change, the compacting extent of M1, M2 subpopulations were much looser under SMG and even with an increase in active, open chromosome regions. In addition, transcriptome data showed that most differentially expressed genes (DEGs) were upregulated, whereas a few DEGs were downregulated in M1 and M2. The functions of both types DEGs were mainly associated with membrane fractions. Additionally, WGS analysis revealed that methylation levels were lower in M1 and M2. Using combined analysis of multi-omics data, we discovered that most upregulated DEGs were significantly enriched in the boundary regions of the variable chromosomal interaction domains (CIDs), in which genes regulating biofilm formation were mainly located. These results suggest that K. pneumoniae may regulate gene expression patterns through DNA methylation and changes in genome structure, thus resulting in new phenotypes in response to altered gravity.
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Affiliation(s)
- Yahao Wang
- Beijing Institute of Biotechnology, Beijing, China
| | - Wenlong Shen
- Beijing Institute of Biotechnology, Beijing, China
| | - Man Yin
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Wenhua Huang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Bingyu Ye
- College of Life Science, Henan Normal University, Xinxiang, China
| | - Ping Li
- Beijing Institute of Biotechnology, Beijing, China
| | - Shu Shi
- Beijing Institute of Biotechnology, Beijing, China
| | - Ge Bai
- Beijing Institute of Biotechnology, Beijing, China
| | - Xinjie Guo
- Beijing Institute of Biotechnology, Beijing, China
| | - Yifei Jin
- Beijing Institute of Biotechnology, Beijing, China
| | - Kailin Lin
- Beijing Institute of Biotechnology, Beijing, China
| | - Yan Zhang
- Beijing Institute of Biotechnology, Beijing, China
| | - Yongqiang Jiang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Junfeng Wang
- Second Medical Center of Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
| | - Yanping Han
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Zhihu Zhao
- Beijing Institute of Biotechnology, Beijing, China
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6
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Kim H, Park B, Park H, Choi I, Rhee M. Low-shear modeled microgravity affects metabolic networks of Escherichia coli O157:H7 EDL933: Further insights into space-microbiology consequences. Food Res Int 2022; 154:111013. [DOI: 10.1016/j.foodres.2022.111013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 02/10/2022] [Accepted: 02/12/2022] [Indexed: 11/04/2022]
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7
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Jang H, Choi SY, Mun W, Jeong SH, Mitchell RJ. Predation of colistin- and carbapenem-resistant bacterial pathogenic populations and their antibiotic resistance genes in simulated microgravity. Microbiol Res 2021; 255:126941. [PMID: 34915266 DOI: 10.1016/j.micres.2021.126941] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/03/2021] [Accepted: 12/03/2021] [Indexed: 10/19/2022]
Abstract
As mankind evaluates moving toward permanently inhabiting outer space and other planetary bodies, alternatives to antibiotic that can effectively control drug-resistant pathogens are needed. The activity of one such alternative, Bdellovibrio bacteriovorus HD100, was explored here, and was found to be as active or better in simulated microgravity (SMG) conditions as in flask and normal gravity (NG) cultures, with the prey viabilities decreasing by 3- to 7-log CFU/mL in 24 h. The activity of B. bacteriovorus HD100 under SMG was also appraised with three different carbapenem- and colistin-resistant pathogenic bacterial strains. In addition to being more efficient at killing two of these pathogens under SMG conditions (with losses of 5- to 6-log CFU/mL), we also explored the ability of B. bacteriovorus HD100 to hydrolyze the carbapenem- and colistin-resistant gene pools, i.e., mcr-1, blaKPC-2 and blaOXA-51, present in these clinical isolates. We found removal efficiencies of 97.4 ± 0.9 %, 97.8 ± 0.4 % and 99.3 ± 0.1 %, respectively, in SMG cultures, while similar reductions were also seen in the flask and NG cultures. These results illustrate the potential applicability of B. bacteriovorus HD100 as an antibiotic to combat the ever-growing threat of multidrug-resistant (MDR) pathogens during spaceflight, such as in the International Space Station (ISS).
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Affiliation(s)
- Hyochan Jang
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea
| | - Seong Yeol Choi
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea
| | - Wonsik Mun
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea
| | - Seok Hoon Jeong
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul 06273, South Korea
| | - Robert J Mitchell
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea.
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Abstract
Microbial research in space is being conducted for almost 50 years now. The closed system of the International Space Station (ISS) has acted as a microbial observatory for the past 10 years, conducting research on adaptation and survivability of microorganisms exposed to space conditions. This adaptation can be either beneficial or detrimental to crew members and spacecraft. Therefore, it becomes crucial to identify the impact of two primary stress conditions, namely, radiation and microgravity, on microbial life aboard the ISS. Elucidating the mechanistic basis of microbial adaptation to space conditions aids in the development of countermeasures against their potentially detrimental effects and allows us to harness their biotechnologically important properties. Several microbial processes have been studied, either in spaceflight or using devices that can simulate space conditions. However, at present, research is limited to only a few microorganisms, and extensive research on biotechnologically important microorganisms is required to make long-term space missions self-sustainable.
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Affiliation(s)
- Swati Bijlani
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90089, USA
| | - Elisa Stephens
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90089, USA
| | - Nitin Kumar Singh
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | | | - Clay C C Wang
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90089, USA
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10
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Santomartino R, Waajen AC, de Wit W, Nicholson N, Parmitano L, Loudon CM, Moeller R, Rettberg P, Fuchs FM, Van Houdt R, Finster K, Coninx I, Krause J, Koehler A, Caplin N, Zuijderduijn L, Zolesi V, Balsamo M, Mariani A, Pellari SS, Carubia F, Luciani G, Leys N, Doswald-Winkler J, Herová M, Wadsworth J, Everroad RC, Rattenbacher B, Demets R, Cockell CS. No Effect of Microgravity and Simulated Mars Gravity on Final Bacterial Cell Concentrations on the International Space Station: Applications to Space Bioproduction. Front Microbiol 2020; 11:579156. [PMID: 33154740 PMCID: PMC7591705 DOI: 10.3389/fmicb.2020.579156] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/09/2020] [Indexed: 12/24/2022] Open
Abstract
Microorganisms perform countless tasks on Earth and they are expected to be essential for human space exploration. Despite the interest in the responses of bacteria to space conditions, the findings on the effects of microgravity have been contradictory, while the effects of Martian gravity are nearly unknown. We performed the ESA BioRock experiment on the International Space Station to study microbe-mineral interactions in microgravity, simulated Mars gravity and simulated Earth gravity, as well as in ground gravity controls, with three bacterial species: Sphingomonas desiccabilis, Bacillus subtilis, and Cupriavidus metallidurans. To our knowledge, this was the first experiment to study simulated Martian gravity on bacteria using a space platform. Here, we tested the hypothesis that different gravity regimens can influence the final cell concentrations achieved after a multi-week period in space. Despite the different sedimentation rates predicted, we found no significant differences in final cell counts and optical densities between the three gravity regimens on the ISS. This suggests that possible gravity-related effects on bacterial growth were overcome by the end of the experiment. The results indicate that microbial-supported bioproduction and life support systems can be effectively performed in space (e.g., Mars), as on Earth.
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Affiliation(s)
- Rosa Santomartino
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Annemiek C Waajen
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Wessel de Wit
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Natasha Nicholson
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Luca Parmitano
- European Space Research and Technology Centre (ESTEC), Noordwijk, Netherlands
| | - Claire-Marie Loudon
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Ralf Moeller
- Radiation Biology Department, German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne (Köln), Germany
| | - Petra Rettberg
- Radiation Biology Department, German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne (Köln), Germany
| | - Felix M Fuchs
- Radiation Biology Department, German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne (Köln), Germany
| | - Rob Van Houdt
- Microbiology Unit, Belgian Nuclear Research Centre, SCK CEN, Mol, Belgium
| | - Kai Finster
- Department of Biology - Microbiology, Aarhus University, Aarhus C, Denmark
| | - Ilse Coninx
- Microbiology Unit, Belgian Nuclear Research Centre, SCK CEN, Mol, Belgium
| | - Jutta Krause
- European Space Research and Technology Centre (ESTEC), Noordwijk, Netherlands
| | - Andrea Koehler
- European Space Research and Technology Centre (ESTEC), Noordwijk, Netherlands
| | - Nicol Caplin
- European Space Research and Technology Centre (ESTEC), Noordwijk, Netherlands
| | - Lobke Zuijderduijn
- European Space Research and Technology Centre (ESTEC), Noordwijk, Netherlands
| | | | | | | | | | | | | | - Natalie Leys
- Microbiology Unit, Belgian Nuclear Research Centre, SCK CEN, Mol, Belgium
| | | | - Magdalena Herová
- BIOTESC, Hochschule Luzern Technik und Architektur, Hergiswil, Switzerland
| | - Jennifer Wadsworth
- Exobiology Branch, NASA Ames Research Center, Moffet Field, CA, United States
| | - R Craig Everroad
- Exobiology Branch, NASA Ames Research Center, Moffet Field, CA, United States
| | - Bernd Rattenbacher
- BIOTESC, Hochschule Luzern Technik und Architektur, Hergiswil, Switzerland
| | - René Demets
- European Space Research and Technology Centre (ESTEC), Noordwijk, Netherlands
| | - Charles S Cockell
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
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11
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Exploration of space to achieve scientific breakthroughs. Biotechnol Adv 2020; 43:107572. [PMID: 32540473 DOI: 10.1016/j.biotechadv.2020.107572] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 05/05/2020] [Accepted: 05/29/2020] [Indexed: 12/13/2022]
Abstract
Living organisms adapt to changing environments using their amazing flexibility to remodel themselves by a process called evolution. Environmental stress causes selective pressure and is associated with genetic and phenotypic shifts for better modifications, maintenance, and functioning of organismal systems. The natural evolution process can be used in complement to rational strain engineering for the development of desired traits or phenotypes as well as for the production of novel biomaterials through the imposition of one or more selective pressures. Space provides a unique environment of stressors (e.g., weightlessness and high radiation) that organisms have never experienced on Earth. Cells in the outer space reorganize and develop or activate a range of molecular responses that lead to changes in cellular properties. Exposure of cells to the outer space will lead to the development of novel variants more efficiently than on Earth. For instance, natural crop varieties can be generated with higher nutrition value, yield, and improved features, such as resistance against high and low temperatures, salt stress, and microbial and pest attacks. The review summarizes the literature on the parameters of outer space that affect the growth and behavior of cells and organisms as well as complex colloidal systems. We illustrate an understanding of gravity-related basic biological mechanisms and enlighten the possibility to explore the outer space environment for application-oriented aspects. This will stimulate biological research in the pursuit of innovative approaches for the future of agriculture and health on Earth.
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12
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Huangfu J, Kim HS, Xu K, Ning X, Qin L, Li J, Li C. Omics Analysis Reveals the Mechanism of Enhanced Recombinant Protein Production Under Simulated Microgravity. Front Bioeng Biotechnol 2020; 8:30. [PMID: 32154223 PMCID: PMC7044180 DOI: 10.3389/fbioe.2020.00030] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 01/14/2020] [Indexed: 11/13/2022] Open
Abstract
Simulated microgravity (SMG) is regarded as a suitable environment to produce recombinant proteins. This study showed that β-glucuronidase expressing Escherichia coli had higher productivity of recombinant protein and higher plasmid copy number under SMG compared with the normal gravity condition. The cellular changes were analyzed at both transcriptomic and proteomic levels. The upregulation of a group of ribosome/RNA polymerase genes and a cluster of genes involving energy metabolism at transcriptomic level stood out for improved production of recombinant protein under SMG. The protein folding modulators such as chaperones were upregulated at proteomic level, which could be a result of the increased activity of protein synthesis and can help recombinant protein production. Protein export was also strengthened, which was revealed at both transcriptomic and proteomic levels. The results demonstrated that SMG is a favorable environment for recombinant protein production arousing the upregulation of protein synthesis, protein folding, and protein export.
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Affiliation(s)
- Jie Huangfu
- Department of Biochemical Engineering/Institute for Synthetic Biosystems, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China.,China National Research Institute of Food & Fermentation Industries, Beijing, China
| | - Hye Su Kim
- Department of Biochemical Engineering/Institute for Synthetic Biosystems, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Ke Xu
- Department of Biochemical Engineering/Institute for Synthetic Biosystems, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China.,Key Lab for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China
| | - Xiaoyu Ning
- Department of Biochemical Engineering/Institute for Synthetic Biosystems, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Lei Qin
- Department of Biochemical Engineering/Institute for Synthetic Biosystems, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Jun Li
- Department of Biochemical Engineering/Institute for Synthetic Biosystems, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Chun Li
- Department of Biochemical Engineering/Institute for Synthetic Biosystems, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
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Modeling Host-Pathogen Interactions in the Context of the Microenvironment: Three-Dimensional Cell Culture Comes of Age. Infect Immun 2018; 86:IAI.00282-18. [PMID: 30181350 DOI: 10.1128/iai.00282-18] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Tissues and organs provide the structural and biochemical landscapes upon which microbial pathogens and commensals function to regulate health and disease. While flat two-dimensional (2-D) monolayers composed of a single cell type have provided important insight into understanding host-pathogen interactions and infectious disease mechanisms, these reductionist models lack many essential features present in the native host microenvironment that are known to regulate infection, including three-dimensional (3-D) architecture, multicellular complexity, commensal microbiota, gas exchange and nutrient gradients, and physiologically relevant biomechanical forces (e.g., fluid shear, stretch, compression). A major challenge in tissue engineering for infectious disease research is recreating this dynamic 3-D microenvironment (biological, chemical, and physical/mechanical) to more accurately model the initiation and progression of host-pathogen interactions in the laboratory. Here we review selected 3-D models of human intestinal mucosa, which represent a major portal of entry for infectious pathogens and an important niche for commensal microbiota. We highlight seminal studies that have used these models to interrogate host-pathogen interactions and infectious disease mechanisms, and we present this literature in the appropriate historical context. Models discussed include 3-D organotypic cultures engineered in the rotating wall vessel (RWV) bioreactor, extracellular matrix (ECM)-embedded/organoid models, and organ-on-a-chip (OAC) models. Collectively, these technologies provide a more physiologically relevant and predictive framework for investigating infectious disease mechanisms and antimicrobial therapies at the intersection of the host, microbe, and their local microenvironments.
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Huang B, Li DG, Huang Y, Liu CT. Effects of spaceflight and simulated microgravity on microbial growth and secondary metabolism. Mil Med Res 2018; 5:18. [PMID: 29807538 PMCID: PMC5971428 DOI: 10.1186/s40779-018-0162-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 04/26/2018] [Indexed: 01/01/2023] Open
Abstract
Spaceflight and ground-based microgravity analog experiments have suggested that microgravity can affect microbial growth and metabolism. Although the effects of microgravity and its analogs on microorganisms have been studied for more than 50 years, plausible conflicting and diverse results have frequently been reported in different experiments, especially regarding microbial growth and secondary metabolism. Until now, only the responses of a few typical microbes to microgravity have been investigated; systematic studies of the genetic and phenotypic responses of these microorganisms to microgravity in space are still insufficient due to technological and logistical hurdles. The use of different test strains and secondary metabolites in these studies appears to have caused diverse and conflicting results. Moreover, subtle changes in the extracellular microenvironments around microbial cells play a key role in the diverse responses of microbial growth and secondary metabolisms. Therefore, "indirect" effects represent a reasonable pathway to explain the occurrence of these phenomena in microorganisms. This review summarizes current knowledge on the changes in microbial growth and secondary metabolism in response to spaceflight and its analogs and discusses the diverse and conflicting results. In addition, recommendations are given for future studies on the effects of microgravity in space on microbial growth and secondary metabolism.
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Affiliation(s)
- Bing Huang
- Nanlou Respiratory Diseases Department, Chinese PLA General Hospital/Chinese PLA Postgraduate Medical School, Beijing, 100853, China
| | - Dian-Geng Li
- Nanlou Respiratory Diseases Department, Chinese PLA General Hospital/Chinese PLA Postgraduate Medical School, Beijing, 100853, China
| | - Ying Huang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Chang-Ting Liu
- Nanlou Respiratory Diseases Department, Chinese PLA General Hospital/Chinese PLA Postgraduate Medical School, Beijing, 100853, China.
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The adaptation of Escherichia coli cells grown in simulated microgravity for an extended period is both phenotypic and genomic. NPJ Microgravity 2017. [PMID: 28649637 PMCID: PMC5460176 DOI: 10.1038/s41526-017-0020-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Microorganisms impact spaceflight in a variety of ways. They play a positive role in biological systems, such as waste water treatment but can be problematic through buildups of biofilms that can affect advanced life support. Of special concern is the possibility that during extended missions, the microgravity environment will provide positive selection for undesirable genomic changes. Such changes could affect microbial antibiotic sensitivity and possibly pathogenicity. To evaluate this possibility, Escherichia coli (lac plus) cells were grown for over 1000 generations on Luria Broth medium under low-shear modeled microgravity conditions in a high aspect rotating vessel. This is the first study of its kind to grow bacteria for multiple generations over an extended period under low-shear modeled microgravity. Comparisons were made to a non-adaptive control strain using growth competitions. After 1000 generations, the final low-shear modeled microgravity-adapted strain readily outcompeted the unadapted lac minus strain. A portion of this advantage was maintained when the low-shear modeled microgravity strain was first grown in a shake flask environment for 10, 20, or 30 generations of growth. Genomic sequencing of the 1000 generation strain revealed 16 mutations. Of the five changes affecting codons, none were neutral. It is not clear how significant these mutations are as individual changes or as a group. It is concluded that part of the long-term adaptation to low-shear modeled microgravity is likely genomic. The strain was monitored for acquisition of antibiotic resistance by VITEK analysis throughout the adaptation period. Despite the evidence of genomic adaptation, resistance to a variety of antibiotics was never observed.
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16
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Kalpana D, Im C, Lee YS. Comparative growth, cross stress resistance, transcriptomics of Streptococcus pyogenes cultured under low shear modeled microgravity and normal gravity. Saudi J Biol Sci 2016; 23:24-33. [PMID: 26858535 PMCID: PMC4705266 DOI: 10.1016/j.sjbs.2015.02.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/29/2015] [Accepted: 02/01/2015] [Indexed: 12/30/2022] Open
Abstract
Streptococcus pyogenes is commonly found on pharynx, mouth and rarely on skin, lower gastrointestinal tract. It is a potential pathogen causing tonsillitis, pneumonia, endocarditis. The present study was undertaken to study the effects of low shear modeled microgravity on growth, morphology, antibiotic resistance, cross-stress resistance to various stresses and alteration in gene expression of S. pyogenes. The growth analysis performed using UV-Visible spectroscopy indicated decrease in growth of S. pyogenes under low shear modeled microgravity. Morphological analysis by Bio-transmission electron microscopy (TEM), Bio-scanning electron microscopy (SEM) did not reveal much difference between normal and low shear modeled microgravity grown S. pyogenes. The sensitivity of S. pyogenes to antibiotics ampicillin, penicillin, streptomycin, kanamycin, hygromycin, rifampicin indicates that the bacterium is resistant to hygromycin. Further S. pyogenes cultured under low shear modeled microgravity was found to be more sensitive to ampicillin and rifampicin as compared with normal gravity grown S. pyogenes. The bacteria were tested for the acid, osmotic, temperature and oxidative cross stress resistances. The gene expression of S. pyogenes under low shear modeled microgravity analyzed by microarray revealed upregulation of 26 genes and down regulation of 22 genes by a fold change of 1.5.
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Affiliation(s)
- Duraisamy Kalpana
- Department of Forest Science and Technology, Institute of Agricultural Science and Technology, Chonbuk National University, Jeonju, South Korea
- Department of Bioresources and Food Science, College of life and Environmental Sciences, Konkuk University, Seoul, South Korea
| | - Chanki Im
- Department of Forest Science and Technology, Institute of Agricultural Science and Technology, Chonbuk National University, Jeonju, South Korea
| | - Yang Soo Lee
- Department of Forest Science and Technology, Institute of Agricultural Science and Technology, Chonbuk National University, Jeonju, South Korea
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Luna C, Yew AG, Hsieh AH. Effects of angular frequency during clinorotation on mesenchymal stem cell morphology and migration. NPJ Microgravity 2015; 1:15007. [PMID: 28725712 PMCID: PMC5515506 DOI: 10.1038/npjmgrav.2015.7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 05/15/2015] [Accepted: 06/12/2015] [Indexed: 02/07/2023] Open
Abstract
AIMS To determine the short-term effects of simulated microgravity on mesenchymal stem cell behaviors-as a function of clinorotation speed-using time-lapse microscopy. BACKGROUND Ground-based microgravity simulation can reproduce the apparent effects of weightlessness in spaceflight using clinostats that continuously reorient the gravity vector on a specimen, creating a time-averaged nullification of gravity. In this work, we investigated the effects of clinorotation speed on the morphology, cytoarchitecture, and migration behavior of human mesenchymal stem cells (hMSCs). METHODS We compared cell responses at clinorotation speeds of 0, 30, 60, and 75 rpm over 8 h in a recently developed lab-on-chip-based clinostat system. Time-lapse light microscopy was used to visualize changes in cell morphology during and after cessation of clinorotation. Cytoarchitecture was assessed by actin and vinculin staining, and chemotaxis was examined using time-lapse light microscopy of cells in NGF (100 ng/ml) gradients. RESULTS Among clinorotated groups, cell area distributions indicated a greater inhibition of cell spreading with higher angular frequency (P<0.005), though average cell area at 30 rpm after 8 h became statistically similar to control (P=0.794). Cells at 75 rpm clinorotation remained viable and were able to re-spread after clinorotation. In chemotaxis chambers, clinorotation did not alter migration patterns in elongated cells, but most clinorotated cells exhibited cell retraction, which strongly compromised motility. CONCLUSIONS These results indicate that hMSCs respond to clinorotation by adopting more rounded, less-spread morphologies. The angular frequency-dependence suggests that a cell's ability to sense the changing gravity vector is governed by the rate of perturbation. For migration studies, cells cultured in clinorotated chemotaxis chambers were generally less motile and exhibited retraction instead of migration.
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Affiliation(s)
- Carlos Luna
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| | - Alvin G Yew
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Adam H Hsieh
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA.,Department of Orthopaedics, University of Maryland, Baltimore, MD, USA
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Huangfu J, Qi F, Liu H, Zou H, Ahmed MS, Li C. Novel helper factors influencing recombinant protein production in Pichia pastoris based on proteomic analysis under simulated microgravity. Appl Microbiol Biotechnol 2014; 99:653-65. [PMID: 25359479 DOI: 10.1007/s00253-014-6175-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 12/20/2022]
Abstract
Microgravity and simulated microgravity (SMG) have quite significant effects on numerous microbial cellular processes. The effects of SMG on the production of recombinant proteins and transcription profiling in prokaryotic and eukaryotic expression host have been investigated. The present study showed that SMG significantly enhanced the specific productivities and activities of the reporter enzymes PGUS and AtXYN that were expressed in recombinant Pichia pastoris. Proteomic profiling revealed that 21 proteins were significantly up-regulated and 35 proteins were drastically down-regulated at the stationary phase, when the recombinant P. pastoris responded to SMG. Six strongly up-regulated genes, TPX, FBA, PGAM, ENO, SBA1, and AKR-E, involved in the oxidative stress response, methanol metabolism, glycolytic pathway, and protein folding, were selected to analyze their impacts on recombinant protein production by co-overexpression in the shaker flask fermentation. The co-overexpressed strains, particularly TPX, FBA, and PGAM, demonstrated promising results with approximately 2.46-fold, 1.58-fold, and 1.33-fold increases in the specific yields of PGUS compared to the control after 48 h of methanol induction, respectively. In the meantime, the corresponding PGUS specific activities were increased by 2.33-fold, 2.09-fold, and 1.32-fold, respectively. Thiol peroxidase (TPX), which is involved in the oxidative stress response, significantly influenced the transcriptional levels of the reporter gene PGUS. The present study provides valuable information for further exploration of the molecular mechanism of P. pastoris response to SMG and facilitates simulated microgravity for finding novel helper factors to rationally engineer the strains in normal fermentation by using proteomic studies.
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Affiliation(s)
- Jie Huangfu
- School of Life Science, Beijing Institute of Technology, 100081, Beijing, People's Republic of China
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Aoyagi H, Kuroda A. Effects of low-shear modeled microgravity on a microbial community filtered through a 0.2-μm filter and its potential application in screening for novel microorganisms. J Biosci Bioeng 2012; 114:73-9. [PMID: 22571963 DOI: 10.1016/j.jbiosc.2012.02.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 02/21/2012] [Accepted: 02/22/2012] [Indexed: 11/24/2022]
Abstract
The effects of low-shear modeled microgravity (LSMMG) on a microbial community filtered through a 0.2-μm filter were investigated, and the potential application of LSMMG in the screening of microorganisms was evaluated. Pond water was passed through a 0.2-μm filter and the filtrate inoculated into two kinds of media (Schneider's insect medium, and ten-times-diluted Schneider's insect [0.1-Sch] medium). The cultures were incubated under LSMMG and normal-gravity and the microbial cell growth rates compared. Cell growth rates, final cell concentrations, and substrate consumption rates were higher in the LSMMG culture than in the normal-gravity culture. The microbial communities obtained under the various culture conditions were subjected to denaturing gradient gel electrophoresis (DGGE), revealing three different groups of microorganisms: (i) microorganisms whose growth rates were increased by LSMMG; (ii) microorganisms whose growth rates were suppressed or inhibited by LSMMG; and (iii) microorganisms whose growth rates were not affected by LSMMG. Sequence analysis of the microorganisms whose growth rates were increased by LSMMG showed that some had high similarity with unculturable microorganisms. When these microorganisms that displayed similarity with unculturable microorganisms were cultivated on agar plates, some of the DGGE bands present in the LSMMG culture were also present. We show that it is possible to isolate and cultivate uncultured microorganisms by using combinations of LSMMG, normal-gravity, and agar plate culturing techniques.
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Affiliation(s)
- Hideki Aoyagi
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
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Vukanti R, Model MA, Leff LG. Effect of modeled reduced gravity conditions on bacterial morphology and physiology. BMC Microbiol 2012; 12:4. [PMID: 22239851 PMCID: PMC3274431 DOI: 10.1186/1471-2180-12-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 01/12/2012] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Bacterial phenotypes result from responses to environmental conditions under which these organisms grow; reduced gravity has been demonstrated in many studies as an environmental condition that profoundly influences microorganisms. In this study, we focused on low-shear stress, modeled reduced gravity (MRG) conditions and examined, for Escherichia coli and Staphlyococcus aureus, a suite of bacterial responses (including total protein concentrations, biovolume, membrane potential and membrane integrity) in rich and dilute media and at exponential and stationary phases for growth. The parameters selected have not been studied in E. coli and S. aureus under MRG conditions and provide critical information about bacterial viability and potential for population growth. RESULTS With the exception of S. aureus in dilute Luria Bertani (LB) broth, specific growth rates (based on optical density) of the bacteria were not significantly different between normal gravity (NG) and MRG conditions. However, significantly higher bacterial yields were observed for both bacteria under MRG than NG, irrespective of the medium with the exception of E. coli grown in LB. Also, enumeration of cells after staining with 4',6-diamidino-2-phenylindole showed that significantly higher numbers were achieved under MRG conditions during stationary phase for E. coli and S. aureus grown in M9 and dilute LB, respectively. In addition, with the exception of smaller S. aureus volume under MRG conditions at exponential phase in dilute LB, biovolume and protein concentrations per cell did not significantly differ between MRG and NG treatments. Both E. coli and S. aureus had higher average membrane potential and integrity under MRG than NG conditions; however, these responses varied with growth medium and growth phase. CONCLUSIONS Overall, our data provides novel information about E. coli and S. aureus membrane potential and integrity and suggest that bacteria are physiologically more active and a larger percentage are viable under MRG as compared to NG conditions. In addition, these results demonstrate that bacterial physiological responses to MRG conditions vary with growth medium and growth phase demonstrating that nutrient resources are a modulator of response.
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Affiliation(s)
- Raja Vukanti
- Department of Biological Sciences, Kent State University, PO Box 5190, Kent, OH 44242, USA
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21
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Measurement of bacterial volume by transmission-through-dye imaging. J Microbiol Methods 2011; 87:375-7. [DOI: 10.1016/j.mimet.2011.08.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 08/26/2011] [Accepted: 08/26/2011] [Indexed: 11/22/2022]
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Induction of attachment-independent biofilm formation and repression of Hfq expression by low-fluid-shear culture of Staphylococcus aureus. Appl Environ Microbiol 2011; 77:6368-78. [PMID: 21803898 DOI: 10.1128/aem.00175-11] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The opportunistic pathogen Staphylococcus aureus encounters a wide variety of fluid shear levels within the human host, and they may play a key role in dictating whether this organism adopts a commensal interaction with the host or transitions to cause disease. By using rotating-wall vessel bioreactors to create a physiologically relevant, low-fluid-shear environment, S. aureus was evaluated for cellular responses that could impact its colonization and virulence. S. aureus cells grown in a low-fluid-shear environment initiated a novel attachment-independent biofilm phenotype and were completely encased in extracellular polymeric substances. Compared to controls, low-shear-cultured cells displayed slower growth and repressed virulence characteristics, including decreased carotenoid production, increased susceptibility to oxidative stress, and reduced survival in whole blood. Transcriptional whole-genome microarray profiling suggested alterations in metabolic pathways. Further genetic expression analysis revealed downregulation of the RNA chaperone Hfq, which parallels low-fluid-shear responses of certain Gram-negative organisms. This is the first study to report an Hfq association with fluid shear in a Gram-positive organism, suggesting an evolutionarily conserved response to fluid shear among structurally diverse prokaryotes. Collectively, our results suggest S. aureus responds to a low-fluid-shear environment by initiating a biofilm/colonization phenotype with diminished virulence characteristics, which could lead to insight into key factors influencing the divergence between infection and colonization during the initial host-pathogen interaction.
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Effects of low-shear modeled microgravity on the characterization of recombinant β-D-glucuronidase expressed in Pichia pastoris. Appl Biochem Biotechnol 2010; 163:162-72. [PMID: 20607443 DOI: 10.1007/s12010-010-9025-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2010] [Accepted: 06/23/2010] [Indexed: 10/19/2022]
Abstract
In this study, we used a high-aspect-ratio vessel (HARV), which could model environment of microgravity on ground to investigate for the first time the effects of low-shear modeled microgravity (LSMMG) on the characterization of recombinant β-D-glucuronidase expressed in Pichia pastoris. The β-D-glucuronidase gene (GenBank accession no. EU095019) derived from Penicillium purpurogenum Li-3 encoding β-D-glucuronidase (PGUS) was expressed in P. pastoris GS115 in two different environments of LSMMG and normal gravity (NG). Results manifested that both LSMMG and NG conditions had insignificant effects on temperature and pH activity (optimal temperature and pH were 55 and 5.0 °C, respectively) and characteristic stability of recombinant PGUS. However, the catalytic activity of recombinant PGUS expressed under LSMMG was less affected by metal ions and EDTA as compared with that of NG. Furthermore, K (m) value of the recombinant PGUS expressed under LSMMG was nearly one fifth of that under NG (1.72 vs. 7.72), whereas catalytic efficiency (k (cat)/K (m)) of PGUS expressed under LSMMG (13.55) was 3.7 times higher than that of NG (3.61). The results initially reveal the significant alterations in catalytic properties of recombinant enzyme in response to LSMMG environment and have potential application in bioprocessing and biocatalysis.
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Abstract
The responses of microorganisms (viruses, bacterial cells, bacterial and fungal spores, and lichens) to selected factors of space (microgravity, galactic cosmic radiation, solar UV radiation, and space vacuum) were determined in space and laboratory simulation experiments. In general, microorganisms tend to thrive in the space flight environment in terms of enhanced growth parameters and a demonstrated ability to proliferate in the presence of normally inhibitory levels of antibiotics. The mechanisms responsible for the observed biological responses, however, are not yet fully understood. A hypothesized interaction of microgravity with radiation-induced DNA repair processes was experimentally refuted. The survival of microorganisms in outer space was investigated to tackle questions on the upper boundary of the biosphere and on the likelihood of interplanetary transport of microorganisms. It was found that extraterrestrial solar UV radiation was the most deleterious factor of space. Among all organisms tested, only lichens (Rhizocarpon geographicum and Xanthoria elegans) maintained full viability after 2 weeks in outer space, whereas all other test systems were inactivated by orders of magnitude. Using optical filters and spores of Bacillus subtilis as a biological UV dosimeter, it was found that the current ozone layer reduces the biological effectiveness of solar UV by 3 orders of magnitude. If shielded against solar UV, spores of B. subtilis were capable of surviving in space for up to 6 years, especially if embedded in clay or meteorite powder (artificial meteorites). The data support the likelihood of interplanetary transfer of microorganisms within meteorites, the so-called lithopanspermia hypothesis.
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Xiang L, Qi F, Dai D, Li C, Jiang Y. Simulated microgravity affects growth of Escherichia coli and recombinant beta-D-glucuronidase production. Appl Biochem Biotechnol 2009; 162:654-61. [PMID: 19921492 DOI: 10.1007/s12010-009-8836-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Accepted: 10/25/2009] [Indexed: 01/10/2023]
Abstract
Effects of simulated microgravity (SMG) on bacteria have been studied in various aspects. However, few reports are available about production of recombinant protein expressed by bacteria in SMG. In this study growth of E. coli BL21 (DE3) cells transformed with pET-28a (+)-pgus in double-axis clinostat that could model low shear SMG environment and the recombinant beta-D-glucuronidase (PGUS) expression have been investigated. Results showed that the cell dry weights in SMG were 16.47%, 38.06%, and 28.79% more than normal gravity (NG) control, and the efficiency of the recombinant PGUS expression in SMG were 18.33%, 19.36%, and 33.42% higher than that in NG at 19 degrees C, 28 degrees C, and 37 degrees C, respectively (P < 0.05).
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Affiliation(s)
- Liang Xiang
- School of Life Science, Beijing Institute of Technology, South Zhongguancun Street, Beijing 100081, People's Republic of China
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