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Millar-Wilson A, Ward Ó, Duffy E, Hardiman G. Multiscale modeling in the framework of biological systems and its potential for spaceflight biology studies. iScience 2022; 25:105421. [DOI: 10.1016/j.isci.2022.105421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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2
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Spaceflight Changes the Production and Bioactivity of Secondary Metabolites in Beauveria bassiana. Toxins (Basel) 2022; 14:toxins14080555. [PMID: 36006216 PMCID: PMC9416017 DOI: 10.3390/toxins14080555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/10/2022] [Accepted: 08/13/2022] [Indexed: 11/16/2022] Open
Abstract
Studies on microorganism response spaceflight date back to 1960. However, nothing conclusive is known concerning the effects of spaceflight on virulence and environmental tolerance of entomopathogenic fungi; thus, this area of research remains open to further exploration. In this study, the entomopathogenic fungus Beauveria bassiana (strain SB010) was exposed to spaceflight (ChangZheng 5 space shuttle during 5 May 2020 to 8 May 2020) as a part of the Key Research and Development Program of Guangdong Province, China, in collaboration with the China Space Program. The study revealed significant differences between the secondary metabolite profiles of the wild isolate (SB010) and the spaceflight-exposed isolate (BHT021, BH030, BHT098) of B. bassiana. Some of the secondary metabolites/toxins, including enniatin A2, brevianamide F, macrosporin, aphidicolin, and diacetoxyscirpenol, were only produced by the spaceflight-exposed isolate (BHT021, BHT030). The study revealed increased insecticidal activities for of crude protein extracts of B. bassiana spaceflight mutants (BHT021 and BH030, respectively) against Megalurothrips usitatus 5 days post application when compared crude protein extracts of the wild isolate (SB010). The data obtained support the idea of using space mutation as a tool for development/screening of fungal strains producing higher quantities of secondary metabolites, ultimately leading to increased toxicity/virulence against the target insect host.
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Adaptation to simulated microgravity in Streptococcus mutans. NPJ Microgravity 2022; 8:17. [PMID: 35654802 PMCID: PMC9163064 DOI: 10.1038/s41526-022-00205-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 05/13/2022] [Indexed: 11/08/2022] Open
Abstract
Long-term space missions have shown an increased incidence of oral disease in astronauts’ and as a result, are one of the top conditions predicted to impact future missions. Here we set out to evaluate the adaptive response of Streptococcus mutans (etiological agent of dental caries) to simulated microgravity. This organism has been well studied on earth and treatment strategies are more predictable. Despite this, we are unsure how the bacterium will respond to the environmental stressors in space. We used experimental evolution for 100-days in high aspect ratio vessels followed by whole genome resequencing to evaluate this adaptive response. Our data shows that planktonic S. mutans did evolve variants in three genes (pknB, SMU_399 and SMU_1307c) that can be uniquely attributed to simulated microgravity populations. In addition, collection of data at multiple time points showed mutations in three additional genes (SMU_399, ptsH and rex) that were detected earlier in simulated microgravity populations than in the normal gravity controls, many of which are consistent with other studies. Comparison of virulence-related phenotypes between biological replicates from simulated microgravity and control orientation cultures generally showed few changes in antibiotic susceptibility, while acid tolerance and adhesion varied significantly between biological replicates and decreased as compared to the ancestral populations. Most importantly, our data shows the importance of a parallel normal gravity control, sequencing at multiple time points and the use of biological replicates for appropriate analysis of adaptation in simulated microgravity.
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Sharma G, Curtis PD. The Impacts of Microgravity on Bacterial Metabolism. Life (Basel) 2022; 12:life12060774. [PMID: 35743807 PMCID: PMC9225508 DOI: 10.3390/life12060774] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/18/2022] [Accepted: 05/20/2022] [Indexed: 12/15/2022] Open
Abstract
The inside of a space-faring vehicle provides a set of conditions unlike anything experienced by bacteria on Earth. The low-shear, diffusion-limited microenvironment with accompanying high levels of ionizing radiation create high stress in bacterial cells, and results in many physiological adaptations. This review gives an overview of the effect spaceflight in general, and real or simulated microgravity in particular, has on primary and secondary metabolism. Some broad trends in primary metabolic responses can be identified. These include increases in carbohydrate metabolism, changes in carbon substrate utilization range, and changes in amino acid metabolism that reflect increased oxidative stress. However, another important trend is that there is no universal bacterial response to microgravity, as different bacteria often have contradictory responses to the same stress. This is exemplified in many of the observed secondary metabolite responses where secondary metabolites may have increased, decreased, or unchanged production in microgravity. Different secondary metabolites in the same organism can even show drastically different production responses. Microgravity can also impact the production profile and localization of secondary metabolites. The inconsistency of bacterial responses to real or simulated microgravity underscores the importance of further research in this area to better understand how microbes can impact the people and systems aboard spacecraft.
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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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6
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Chen X, Li C, Liu H. Enhanced Recombinant Protein Production Under Special Environmental Stress. Front Microbiol 2021; 12:630814. [PMID: 33935992 PMCID: PMC8084102 DOI: 10.3389/fmicb.2021.630814] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/19/2021] [Indexed: 01/09/2023] Open
Abstract
Regardless of bacteria or eukaryotic microorganism hosts, improving their ability to express heterologous proteins is always a goal worthy of elaborate study. In addition to traditional methods including intracellular synthesis process regulation and extracellular environment optimization, some special or extreme conditions can also be employed to create an enhancing effect on heterologous protein production. In this review, we summarize some extreme environmental factors used for the improvement of heterologous protein expression, including low temperature, hypoxia, microgravity and high osmolality. The applications of these strategies are elaborated with examples of well-documented studies. We also demonstrated the confirmed or hypothetical mechanisms of environment stress affecting the host behaviors. In addition, multi-omics techniques driving the stress-responsive research for construction of efficient microbial cell factories are also prospected at the end.
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Affiliation(s)
- Xinyi Chen
- Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Chun Li
- Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China.,Key Laboratory for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China.,Center for Synthetic & Systems Biology, Tsinghua University, Beijing, China
| | - Hu Liu
- Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
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7
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Senatore G, Mastroleo F, Leys N, Mauriello G. Growth of Lactobacillus reuteri DSM17938 Under Two Simulated Microgravity Systems: Changes in Reuterin Production, Gastrointestinal Passage Resistance, and Stress Genes Expression Response. ASTROBIOLOGY 2020; 20:1-14. [PMID: 31977256 DOI: 10.1089/ast.2019.2082] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Extreme factors such as space microgravity, radiation, and magnetic field differ from those that occur on Earth. Microgravity may induce and select some microorganisms for physiological, metabolic, and/or genetic variations. This study was conducted to determine the effects of simulated microgravity conditions on the metabolism and gene expression of the probiotic bacterium Lactobacillus reuteri DSM17938. To investigate microbial response to simulated microgravity, two devices-the rotating wall vessel (RWV) and the random positioning machine (RPM)-were used. Microbial growth, reuterin production, and resistance to gastrointestinal passage were assessed, and morphological characteristics were analyzed by scanning electron microscopy. The expression of some selected genes that are responsive to stress conditions and to bile salts stress was evaluated through real-time quantitative polymerase chain reaction assay. Monitoring of bacterial growth, cell size, and shape under simulated microgravity did not reveal differences compared with 1 × g controls. On the contrary, an enhanced production of reuterin and a greater tolerance to the gastrointestinal passage were observed. Moreover, some stress genes were upregulated under RWV conditions, especially after 24 h of treatment, whereas RPM conditions seemed to determine a downregulation over time of the same stress genes. These results show that simulated microgravity could alter some physiological characteristics of L. reuteri DSM17938 with regard to tolerance toward stress conditions encountered on space missions and could be useful to elucidate the adaptation mechanisms of microbes to the space environment.
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Affiliation(s)
- Giuliana Senatore
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
| | - Felice Mastroleo
- Microbiology Unit, Belgian Nuclear Research Centre (SCK●CEN), Mol, Belgium
| | - Natalie Leys
- Microbiology Unit, Belgian Nuclear Research Centre (SCK●CEN), Mol, Belgium
| | - Gianluigi Mauriello
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
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Transcriptional profiling of the mutualistic bacterium Vibrio fischeri and an hfq mutant under modeled microgravity. NPJ Microgravity 2018; 4:25. [PMID: 30588486 PMCID: PMC6299092 DOI: 10.1038/s41526-018-0060-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 11/05/2018] [Indexed: 02/06/2023] Open
Abstract
For long-duration space missions, it is critical to maintain health-associated homeostasis between astronauts and their microbiome. To achieve this goal it is important to more fully understand the host–symbiont relationship under the physiological stress conditions of spaceflight. To address this issue we examined the impact of a spaceflight analog, low-shear-modeled microgravity (LSMMG), on the transcriptome of the mutualistic bacterium Vibrio fischeri. Cultures of V. fischeri and a mutant defective in the global regulator Hfq (∆hfq) were exposed to either LSMMG or gravity conditions for 12 h (exponential growth) and 24 h (stationary phase growth). Comparative transcriptomic analysis revealed few to no significant differentially expressed genes between gravity and the LSMMG conditions in the wild type or mutant V. fischeri at exponential or stationary phase. There was, however, a pronounced change in transcriptomic profiles during the transition between exponential and stationary phase growth in both V. fischeri cultures including an overall decrease in gene expression associated with translational activity and an increase in stress response. There were also several upregulated stress genes specific to the LSMMG condition during the transition to stationary phase growth. The ∆hfq mutants exhibited a distinctive transcriptome profile with a significant increase in transcripts associated with flagellar synthesis and transcriptional regulators under LSMMG conditions compared to gravity controls. These results indicate the loss of Hfq significantly influences gene expression under LSMMG conditions in a bacterial symbiont. Together, these results improve our understanding of the mechanisms by which microgravity alters the physiology of beneficial host-associated microbes.
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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: 44] [Impact Index Per Article: 7.3] [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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11
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Senatore G, Mastroleo F, Leys N, Mauriello G. Effect of microgravity & space radiation on microbes. Future Microbiol 2018; 13:831-847. [PMID: 29745771 DOI: 10.2217/fmb-2017-0251] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
One of the new challenges facing humanity is to reach increasingly further distant space targets. It is therefore of upmost importance to understand the behavior of microorganisms that will unavoidably reach the space environment together with the human body and equipment. Indeed, microorganisms could activate their stress defense mechanisms, modifying properties related to human pathogenesis. The host-microbe interactions, in fact, could be substantially affected under spaceflight conditions and the study of microorganisms' growth and activity is necessary for predicting these behaviors and assessing precautionary measures during spaceflight. This review gives an overview of the effects of microgravity and space radiation on microorganisms both in real and simulated conditions.
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Affiliation(s)
- Giuliana Senatore
- Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Naples, Italy
| | - Felice Mastroleo
- Microbiology Unit, Belgian Nuclear Research Centre (SCK•CEN), 2400 Mol, Belgium
| | - Natalie Leys
- Microbiology Unit, Belgian Nuclear Research Centre (SCK•CEN), 2400 Mol, Belgium
| | - Gianluigi Mauriello
- Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Naples, Italy
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12
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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: 31] [Impact Index Per Article: 4.4] [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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Yoo YJ, Kim H, Park SR, Yoon YJ. An overview of rapamycin: from discovery to future perspectives. J Ind Microbiol Biotechnol 2016; 44:537-553. [PMID: 27613310 DOI: 10.1007/s10295-016-1834-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 08/22/2016] [Indexed: 12/17/2022]
Abstract
Rapamycin is an immunosuppressive metabolite produced from several actinomycete species. Besides its immunosuppressive activity, rapamycin and its analogs have additional therapeutic potentials, including antifungal, antitumor, neuroprotective/neuroregenerative, and lifespan extension activities. The core structure of rapamycin is derived from (4R,5R)-4,5-dihydrocyclohex-1-ene-carboxylic acid that is extended by polyketide synthase. The resulting linear polyketide chain is cyclized by incorporating pipecolate and further decorated by post-PKS modification enzymes. Herein, we review the discovery and biological activities of rapamycin as well as its mechanism of action, mechanistic target, biosynthesis, and regulation. In addition, we introduce the many efforts directed at enhancing the production of rapamycin and generating diverse analogs and also explore future perspectives in rapamycin research. This review will also emphasize the remarkable pilot studies on the biosynthesis and production improvement of rapamycin by Dr. Demain, one of the world's distinguished scientists in industrial microbiology and biotechnology.
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Affiliation(s)
- Young Ji Yoo
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul, 120-750, Republic of Korea
| | - Hanseong Kim
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Sung Ryeol Park
- Natural Products Discovery Institute, The Baruch S. Blumberg Institute, Hepatitis B Foundation, Doylestown, PA, 18902, USA.
| | - Yeo Joon Yoon
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul, 120-750, Republic of Korea.
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14
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Liu C. The theory and application of space microbiology: China's experiences in space experiments and beyond. Environ Microbiol 2016; 19:426-433. [PMID: 27459305 DOI: 10.1111/1462-2920.13472] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Accepted: 07/22/2016] [Indexed: 12/22/2022]
Abstract
Microorganisms exhibit high adaptability to extreme environments of outer space via phenotypic and genetic changes. These changes may affect astronauts in the space environment as well as on Earth because mutant microbes will inevitably return with the spacecraft. However, the role and significance of these phenotypic changes and the underlying mechanisms are important unresolved questions in the field of space biology. By reviewing, especially the Chinese studies, we propose a space microbial molecular effect theory, that is, the space environment affects the nature of genes and the molecular structure of microorganisms to produce phenotypic changes. In this review, we discussed three basic theories for the research of space microbiology, including (1) space microbial pathogenicity and virulence mutations and the human mutualism theory; (2) space microbial drug-resistance mutations and metabolism associated with space pharmaceuticals theory; (3) space corrosion, microbial decontamination, and new materials technology theory.
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Affiliation(s)
- Changting Liu
- Nanlou Respiratory Diseases Department, Chinese PLA General Hospital, Beijing, China
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15
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Huangfu J, Zhang G, Li J, Li C. Advances in engineered microorganisms for improving metabolic conversion via microgravity effects. Bioengineered 2016; 6:251-5. [PMID: 26038088 DOI: 10.1080/21655979.2015.1056942] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
As an extreme and unique environment, microgravity has significant effects on microbial cellular processes, such as cell growth, gene expression, natural pathways and biotechnological products. Application of microgravity effects to identify the regulatory elements in reengineering microbial hosts will draw much more attention in further research. In this commentary, we discuss the microgravity effects in engineered microorganisms for improving metabolic conversion, including cell growth kinetics, antimicrobial susceptibility, resistance to stresses, secondary metabolites production, recombinant protein production and enzyme activity, as well as gene expression changes. Application of microgravity effects in engineered microorganisms could provide valuable platform for innovative approaches in bioprocessing technology to largely improve the metabolic conversion efficacy of biopharmaceutical products.
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Affiliation(s)
- Jie Huangfu
- a School of Life Science ; Beijing Institute of Technology ; Beijing , China
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16
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Sun Y, Hu D, Li L, Jing Z, Wei C, Zhang L, Fu Y, Liu H. Influence mechanism of low-dose ionizing radiation on Escherichia coli DH5α population based on plasma theory and system dynamics simulation. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 151 Pt 1:185-192. [PMID: 26479196 DOI: 10.1016/j.jenvrad.2015.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 09/16/2015] [Accepted: 10/06/2015] [Indexed: 06/05/2023]
Abstract
It remains a mystery why the growth rate of bacteria is higher in low-dose ionizing radiation (LDIR) environment than that in normal environment. In this study, a hypothesis composed of environmental selection and competitive exclusion was firstly proposed from observed phenomena, experimental data and microbial ecology. Then a LDIR environment simulator (LDIRES) was built to cultivate a model organism of bacteria, Escherichia coli (E. coli) DH5α, the accurate response of bacterial population to ionizing radiation intensity variation was measured experimentally, and then the precise relative dosage of ionizing radiation E. coli DH5α population received was calculated by finite element analysis based on drift-diffusion equations of plasma. Finally, a highly valid mathematical model expressing the relationship between E. coli DH5α population and LDIR intensity was developed by system dynamics based on hypotheses, experimental data and microbial ecology. Both experiment and simulation results clearly showed that the E. coli DH5α individuals with greater specific growth rate and lower substrate consumption coefficient would adapt and survive in LDIR environment and those without such adaptability were finally eliminated under the combined effects of ionizing radiation selection and competitive exclusion.
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Affiliation(s)
- Yi Sun
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; State Key Laboratory of Virtual Reality Technology and Systems, School of Computer Science and Engineering, Beihang University, Beijing 100191, China; International Joint Research Center of Aerospace Biotechnology & Medical, Engineering, Beihang University, Beijing 100191, China
| | - Dawei Hu
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; State Key Laboratory of Virtual Reality Technology and Systems, School of Computer Science and Engineering, Beihang University, Beijing 100191, China; Institute of Environmental Biology and Life Support Technology, Beihang University, Beijing 100191, China; International Joint Research Center of Aerospace Biotechnology & Medical, Engineering, Beihang University, Beijing 100191, China
| | - Liang Li
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; State Key Laboratory of Virtual Reality Technology and Systems, School of Computer Science and Engineering, Beihang University, Beijing 100191, China; Institute of Environmental Biology and Life Support Technology, Beihang University, Beijing 100191, China
| | - Zheng Jing
- China Academy of Space Technology, Beijing 100094, China
| | - Chuanfeng Wei
- China Academy of Space Technology, Beijing 100094, China
| | - Lantao Zhang
- China Academy of Space Technology, Beijing 100094, China
| | - Yuming Fu
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; Institute of Environmental Biology and Life Support Technology, Beihang University, Beijing 100191, China; International Joint Research Center of Aerospace Biotechnology & Medical, Engineering, Beihang University, Beijing 100191, China
| | - Hong Liu
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; State Key Laboratory of Virtual Reality Technology and Systems, School of Computer Science and Engineering, Beihang University, Beijing 100191, China; Institute of Environmental Biology and Life Support Technology, Beihang University, Beijing 100191, China.
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17
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Effects of simulated microgravity and spaceflight on morphological differentiation and secondary metabolism of Streptomyces coelicolor A3(2). Appl Microbiol Biotechnol 2015; 99:4409-22. [DOI: 10.1007/s00253-015-6386-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 12/31/2014] [Accepted: 01/05/2015] [Indexed: 02/07/2023]
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18
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Zhang G, Qi F, Jia H, Zou C, Li C. Advances in bioprocessing for efficient bio manufacture. RSC Adv 2015. [DOI: 10.1039/c5ra07699d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The strategies involving molecular, cellular and community levels for improving various bioprocesses are reviewed with specific examples presented.
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Affiliation(s)
- Genlin Zhang
- School of Life Sciences
- Beijing Institute of Technology
- Beijing 100081
- China
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan
| | - Feng Qi
- School of Life Sciences
- Beijing Institute of Technology
- Beijing 100081
- China
- College of Life Sciences/Engineering Research Center of Industrial Microbiology
| | - Haiyang Jia
- School of Life Sciences
- Beijing Institute of Technology
- Beijing 100081
- China
| | - Changling Zou
- School of Physics
- Beijing Institute of Technology
- Beijing 100081
- China
| | - Chun Li
- School of Life Sciences
- Beijing Institute of Technology
- Beijing 100081
- China
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Rosenzweig JA, Ahmed S, Eunson J, Chopra AK. Low-shear force associated with modeled microgravity and spaceflight does not similarly impact the virulence of notable bacterial pathogens. Appl Microbiol Biotechnol 2014; 98:8797-807. [PMID: 25149449 DOI: 10.1007/s00253-014-6025-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/06/2014] [Accepted: 08/08/2014] [Indexed: 12/18/2022]
Abstract
As their environments change, microbes experience various threats and stressors, and in the hypercompetitive microbial world, dynamism and the ability to rapidly respond to such changes allow microbes to outcompete their nutrient-seeking neighbors. Viewed in that light, the very difference between microbial life and death depends on effective stress response mechanisms. In addition to the more commonly studied temperature, nutritional, and chemical stressors, research has begun to characterize microbial responses to physical stress, namely low-shear stress. In fact, microbial responses to low-shear modeled microgravity (LSMMG), which emulates the microgravity experienced in space, have been studied quite widely in both prokaryotes and eukaryotes. Interestingly, LSMMG-induced changes in the virulence potential of several Gram-negative enteric bacteria, e.g., an increased enterotoxigenic Escherichia coli-mediated fluid secretion in ligated ileal loops of mice, an increased adherent invasive E. coli-mediated infectivity of Caco-2 cells, an increased Salmonella typhimurium-mediated invasion of both epithelial and macrophage cells, and S. typhimurium hypervirulence phenotype in BALB/c mice when infected by the intraperitoneal route. Although these were some examples where virulence of the bacteria was increased, there are instances where organisms became less virulent under LSMMG, e.g., hypovirulence of Yersinia pestis in cell culture infections and hypovirulence of methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, and Listeria monocytogenes in a Caenorhabditis elegans infection model. In general, a number of LSMMG-exposed bacteria (but not all) seemed better equipped to handle subsequent stressors such as osmotic shock, acid shock, heat shock, and exposure to chemotherapeutics. This mini-review primarily discusses both LSMMG-induced as well as bona fide spaceflight-specific alterations in bacterial virulence potential, demonstrating that pathogens' responses to low-shear forces vary dramatically. Ultimately, a careful characterization of numerous bacterial pathogens' responses to low-shear forces is necessary to evaluate a more complete picture of how this physical stress impacts bacterial virulence since a "one-size-fits-all" response is clearly not the case.
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Affiliation(s)
- Jason A Rosenzweig
- Department of Biology and Center for Bionanotechnology and Environmental Research, Texas Southern University, 3100 Cleburne Street, Houston, TX, 77004, USA,
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Foster JS, Wheeler RM, Pamphile R. Host-microbe interactions in microgravity: assessment and implications. Life (Basel) 2014; 4:250-66. [PMID: 25370197 PMCID: PMC4187166 DOI: 10.3390/life4020250] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Revised: 05/14/2014] [Accepted: 05/20/2014] [Indexed: 01/07/2023] Open
Abstract
Spaceflight imposes several unique stresses on biological life that together can have a profound impact on the homeostasis between eukaryotes and their associated microbes. One such stressor, microgravity, has been shown to alter host-microbe interactions at the genetic and physiological levels. Recent sequencing of the microbiomes associated with plants and animals have shown that these interactions are essential for maintaining host health through the regulation of several metabolic and immune responses. Disruptions to various environmental parameters or community characteristics may impact the resiliency of the microbiome, thus potentially driving host-microbe associations towards disease. In this review, we discuss our current understanding of host-microbe interactions in microgravity and assess the impact of this unique environmental stress on the normal physiological and genetic responses of both pathogenic and mutualistic associations. As humans move beyond our biosphere and undergo longer duration space flights, it will be essential to more fully understand microbial fitness in microgravity conditions in order to maintain a healthy homeostasis between humans, plants and their respective microbiomes.
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Affiliation(s)
- Jamie S Foster
- Space Life Science Lab, University of Florida, 505 Odyssey Way, Merritt Island, FL 32953, USA.
| | | | - Regine Pamphile
- Space Life Science Lab, University of Florida, 505 Odyssey Way, Merritt Island, FL 32953, USA.
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21
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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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22
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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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23
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Simulated microgravity affects semicarbazide-sensitive amine oxidase expression in recombinant Escherichia coli by HPLC-ESI-QQQ analysis. Appl Microbiol Biotechnol 2011; 94:809-16. [DOI: 10.1007/s00253-011-3652-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Revised: 09/28/2011] [Accepted: 10/17/2011] [Indexed: 11/25/2022]
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Deguchi S, Shimoshige H, Tsudome M, Mukai SA, Corkery RW, Ito S, Horikoshi K. Microbial growth at hyperaccelerations up to 403,627 x g. Proc Natl Acad Sci U S A 2011; 108:7997-8002. [PMID: 21518884 PMCID: PMC3093466 DOI: 10.1073/pnas.1018027108] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It is well known that prokaryotic life can withstand extremes of temperature, pH, pressure, and radiation. Little is known about the proliferation of prokaryotic life under conditions of hyperacceleration attributable to extreme gravity, however. We found that living organisms can be surprisingly proliferative during hyperacceleration. In tests reported here, a variety of microorganisms, including Gram-negative Escherichia coli, Paracoccus denitrificans, and Shewanella amazonensis; Gram-positive Lactobacillus delbrueckii; and eukaryotic Saccharomyces cerevisiae, were cultured while being subjected to hyperaccelerative conditions. We observed and quantified robust cellular growth in these cultures across a wide range of hyperacceleration values. Most notably, the organisms P. denitrificans and E. coli were able to proliferate even at 403,627 × g. Analysis shows that the small size of prokaryotic cells is essential for their proliferation under conditions of hyperacceleration. Our results indicate that microorganisms cannot only survive during hyperacceleration but can display such robust proliferative behavior that the habitability of extraterrestrial environments must not be limited by gravity.
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Affiliation(s)
- Shigeru Deguchi
- Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan.
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25
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Sánchez S. Arnold Lester Demain: a good friend, an outstanding scientist and a valuable professor. J Antibiot (Tokyo) 2010; 63:412-4. [DOI: 10.1038/ja.2010.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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26
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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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27
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Biosynthesis of rapamycin and its regulation: past achievements and recent progress. J Antibiot (Tokyo) 2010; 63:434-41. [PMID: 20588302 DOI: 10.1038/ja.2010.71] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Rapamycin and its analogs are clinically important macrolide compounds produced by Streptomyces hygroscopicus. They exhibit antifungal, immunosuppressive, antitumor, neuroprotective and antiaging activities. The core macrolactone ring of rapamycin is biosynthesized by hybrid type I modular polyketide synthase (PKS)/nonribosomal peptide synthetase systems primed with 4,5-dihydrocyclohex-1-ene-carboxylic acid. The linear polyketide chain is condensed with pipecolate by peptide synthetase, followed by cyclization to form the macrolide ring and modified by a series of post-PKS tailoring steps. The aim of this review was to outline past and recent advances in the biosynthesis and regulation of rapamycin, with an emphasis on the distinguished contributions of Professor Demain to the study of rapamycin. In addition, this article describes the biological activities as well as mechanism of action of rapamycin and its derivatives. Recent attempts to improve the productivity of rapamycin and generate diverse rapamycin analogs through mutasynthesis and mutagenesis are also introduced, along with some future perspectives.
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28
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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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29
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Abstract
Plans by the space program to use plants for food supply and environmental regeneration have led to an examination of how plants grow in microgravity. Because secondary metabolic compounds are so important in determining the nutritional and flavor characteristics of plants-as well as making plants more resistant to biotic and abiotic stresses-their responses to altered gravity are now being studied. These experiments are technically challenging because temperature, humidity, atmospheric composition, light, and water status must be maintained around the plant while simultaneously altering the g-load, either in the free-fall of orbital spacecraft or on a centrifuge rotor. In general, plants have shown increased accumulation of small secondary metabolites in microgravity (<10(-3) g), while these have decreased in hypergravity (>1-g). Gravity-related changes in the plant environment as well as mechanical loading effects account for these responses.
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Affiliation(s)
- Lindsey K Tuominen
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA
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30
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Allen CA, Niesel DW, Torres AG. The effects of low-shear stress on Adherent-invasive Escherichia coli. Environ Microbiol 2008; 10:1512-25. [PMID: 18312396 DOI: 10.1111/j.1462-2920.2008.01567.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The impact of low-shear stress (LSS) was evaluated on an Adherent-invasive Escherichia coli clinical isolate (AIEC strain O83:H1) from a Crohn's disease patient. High-aspect ratio vessels (HARVs) were used to model LSS conditions to characterize changes in environmental stress resistance and adhesion/invasive properties. Low-shear stress-grown cultures exhibited enhanced thermal and oxidative stress resistance as well as increased adherence to Caco-2 cells, but no changes in invasion were observed. An AIEC rpoS mutant was constructed to examine the impact of this global stress regulator. The absence of RpoS under LSS conditions resulted in increased sensitivity to oxidative stress while adherence levels were elevated in comparison with the wild-type strain. TnphoA mutagenesis and rpoS complementation were carried out on the rpoS mutant to identify those factors involved in the LSS-induced adherence phenotype. Mutagenesis results revealed that one insertion disrupted the tnaB gene (encoding tryptophan permease) and the rpoS tnaB double mutant exhibited decreased adherence under LSS. Complementation of the tnaB gene, or medium supplemented with exogenous indole, restored adhesion of the rpoS tnaB mutant under LSS conditions. Overall, our study demonstrated how mechanical stresses such as LSS altered AIEC phenotypic characteristics and identified novel functions for some RpoS-regulated proteins.
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Affiliation(s)
- Christopher A Allen
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555-1070, USA
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31
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Purevdorj-Gage B, Sheehan KB, Hyman LE. Effects of low-shear modeled microgravity on cell function, gene expression, and phenotype in Saccharomyces cerevisiae. Appl Environ Microbiol 2006; 72:4569-75. [PMID: 16820445 PMCID: PMC1489333 DOI: 10.1128/aem.03050-05] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Only limited information is available concerning the effects of low-shear modeled microgravity (LSMMG) on cell function and morphology. We examined the behavior of Saccharomyces cerevisiae grown in a high-aspect-ratio vessel, which simulates the low-shear and microgravity conditions encountered in spaceflight. With the exception of a shortened lag phase (90 min less than controls; P < 0.05), yeast cells grown under LSMMG conditions did not differ in growth rate, size, shape, or viability from the controls but did differ in the establishment of polarity as exhibited by aberrant (random) budding compared to the usual bipolar pattern of controls. The aberrant budding was accompanied by an increased tendency of cells to clump, as indicated by aggregates containing five or more cells. We also found significant changes (greater than or equal to twofold) in the expression of genes associated with the establishment of polarity (BUD5), bipolar budding (RAX1, RAX2, and BUD25), and cell separation (DSE1, DSE2, and EGT2). Thus, low-shear environments may significantly alter yeast gene expression and phenotype as well as evolutionary conserved cellular functions such as polarization. The results provide a paradigm for understanding polarity-dependent cell responses to microgravity ranging from pathogenesis in fungi to the immune response in mammals.
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Affiliation(s)
- B Purevdorj-Gage
- Division of Health Sciences, WWAMI Medical Program, Montana State University, 308 Leon Johnson Hall, P.O. Box 173080, Bozeman, MT 59717, USA
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32
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Benoit MR, Li W, Stodieck LS, Lam KS, Winther CL, Roane TM, Klaus DM. Microbial antibiotic production aboard the International Space Station. Appl Microbiol Biotechnol 2005; 70:403-11. [PMID: 16091928 DOI: 10.1007/s00253-005-0098-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2005] [Revised: 07/08/2005] [Accepted: 07/10/2005] [Indexed: 10/25/2022]
Abstract
Previous studies examining metabolic characteristics of bacterial cultures have mostly suggested that reduced gravity is advantageous for microbial growth. As a consequence, the question of whether space flight would similarly enhance secondary metabolite production was raised. Results from three prior space shuttle experiments indicated that antibiotic production was stimulated in space for two different microbial systems, albeit under suboptimal growth conditions. The goal of this latest experiment was to determine whether the enhanced productivity would also occur with better growth conditions and over longer durations of weightlessness. Microbial antibiotic production was examined onboard the International Space Station during the 72-day 8A increment. Findings of increased productivity of actinomycin D by Streptomyces plicatus in space corroborated with previous findings for the early sample points (days 8 and 12); however, the flight production levels were lower than the matched ground control samples for the remainder of the mission. The overall goal of this research program is to elucidate the specific mechanisms responsible for the initial stimulation of productivity in space and translate this knowledge into methods for improving efficiency of commercial production facilities on Earth.
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Affiliation(s)
- M R Benoit
- BioServe Space Technologies, Aerospace Engineering Sciences Department, University of Colorado, Boulder, USA
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33
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Graebe A, Schuck EL, Lensing P, Putcha L, Derendorf H. Physiological, pharmacokinetic, and pharmacodynamic changes in space. J Clin Pharmacol 2005; 44:837-53. [PMID: 15286087 DOI: 10.1177/0091270004267193] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Medications have been taken since the first Mercury flight in 1967 and, since then, have been used for several indications such as space motion sickness, sleeplessness, headache, nausea, vomiting, back pain, and congestion. As the duration of space missions get longer, it is even more likely that astronauts will encounter some of the acute illnesses that are frequently seen on Earth. Microgravity environment induces several physiological changes in the human body. These changes include cardiovascular degeneration, bone decalcification, decreased plasma volume, blood flow, lymphocyte and eosinophil levels, altered hormonal and electrolyte levels, muscle atrophy, decreased blood cell mass, increased immunoglobulin A and M levels, and a decrease in the amount of microsomal P-450 and the activity of some of its dependent enzymes. These changes may be expected to have severe implications on the pharmacokinetic and pharmacodynamic properties of drug substances.
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Affiliation(s)
- Annemarie Graebe
- Department of Pharmacy Practice and Administration, Ernest Mario School of Pharmacy, Rutgers, State University of New Jersey, USA
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Abstract
My professional life has been devoted to the study of microbial products and their biosynthesis, regulation, and overproduction. These have included primary metabolites (glutamic acid, tryptophan, inosinic acid, guanylic acid, vitamin B(12), riboflavin, pantothenic acid, ethanol, and lactic acid) and secondary metabolites (penicillin, cephalosporins, streptomycin, fosfomycin, gramicidin S, rapamycin, indolmycin, microcin B17, fumagillin, mycotoxins, Monascus pigments, and tetramethylpyrazine). Other areas included microbial nutrition, strain improvement, bioconversions of statins and beta-lactams, sporulation and germination, plasmid stability, gel microdroplets, and the production of double-stranded RNA, the polymer xanthan, and enzymes (polygalacturonase, protease, cellulase). Most of the studies were carried out with me by devoted and hardworking industrial scientists for 15 years at Merck & Co. and by similarly characterized students, postdoctorals, and visiting scientists during my 32 years at the Massachusetts Institute of Technology. I owe much of my success to my mentors from academia and industry. My recent research activities with undergraduate students at the Charles A. Dana Research Institute for Scientists Emeriti (R.I.S.E.) at Drew University have been very rewarding and are allowing me to continue my career.
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Affiliation(s)
- Arnold L Demain
- Charles A. Dana Research Institute for Scientists Emeriti (R.I.S.E), Drew University, Madison, New Jersey 07940, USA.
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Nickerson CA, Ott CM, Wilson JW, Ramamurthy R, Pierson DL. Microbial responses to microgravity and other low-shear environments. Microbiol Mol Biol Rev 2004; 68:345-61. [PMID: 15187188 PMCID: PMC419922 DOI: 10.1128/mmbr.68.2.345-361.2004] [Citation(s) in RCA: 202] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Microbial adaptation to environmental stimuli is essential for survival. While several of these stimuli have been studied in detail, recent studies have demonstrated an important role for a novel environmental parameter in which microgravity and the low fluid shear dynamics associated with microgravity globally regulate microbial gene expression, physiology, and pathogenesis. In addition to analyzing fundamental questions about microbial responses to spaceflight, these studies have demonstrated important applications for microbial responses to a ground-based, low-shear stress environment similar to that encountered during spaceflight. Moreover, the low-shear growth environment sensed by microbes during microgravity of spaceflight and during ground-based microgravity analogue culture is relevant to those encountered during their natural life cycles on Earth. While no mechanism has been clearly defined to explain how the mechanical force of fluid shear transmits intracellular signals to microbial cells at the molecular level, the fact that cross talk exists between microbial signal transduction systems holds intriguing possibilities that future studies might reveal common mechanotransduction themes between these systems and those used to sense and respond to low-shear stress and changes in gravitation forces. The study of microbial mechanotransduction may identify common conserved mechanisms used by cells to perceive changes in mechanical and/or physical forces, and it has the potential to provide valuable insight for understanding mechanosensing mechanisms in higher organisms. This review summarizes recent and future research trends aimed at understanding the dynamic effects of changes in the mechanical forces that occur in microgravity and other low-shear environments on a wide variety of important microbial parameters.
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Affiliation(s)
- Cheryl A Nickerson
- Program in Molecular Pathogenesis and Immunity, Department of Microbiology and Immunology, SL38, Tulane University School of Medicine, 1430 Tulane Ave., New Orleans, LA 70112-2699, USA.
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Nickerson CA, Ott CM, Wilson JW, Ramamurthy R, LeBlanc CL, Höner zu Bentrup K, Hammond T, Pierson DL. Low-shear modeled microgravity: a global environmental regulatory signal affecting bacterial gene expression, physiology, and pathogenesis. J Microbiol Methods 2003; 54:1-11. [PMID: 12732416 DOI: 10.1016/s0167-7012(03)00018-6] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Bacteria inhabit an impressive variety of ecological niches and must adapt constantly to changing environmental conditions. While numerous environmental signals have been examined for their effect on bacteria, the effects of mechanical forces such as shear stress and gravity have only been investigated to a limited extent. However, several important studies have demonstrated a key role for the environmental signals of low shear and/or microgravity in the regulation of bacterial gene expression, physiology, and pathogenesis [Chem. Rec. 1 (2001) 333; Appl. Microbiol. Biotechnol. 54 (2000) 33; Appl. Environ. Microbiol. 63 (1997) 4090; J. Ind. Microbiol. 18 (1997) 22; Curr. Microbiol. 34(4) (1997) 199; Appl. Microbiol. Biotechnol. 56(3-4) (2001) 384; Infect Immun. 68(6) (2000) 3147; Cell 109(7) (2002) 913; Appl. Environ. Microbiol. 68(11) (2002) 5408; Proc. Natl. Acad. Sci. U. S. A. 99(21) (2002) 13807]. The response of bacteria to these environmental signals, which are similar to those encountered during prokaryotic life cycles, may provide insight into bacterial adaptations to physiologically relevant conditions. This review focuses on the current and potential future research trends aimed at understanding the effect of the mechanical forces of low shear and microgravity analogues on different bacterial parameters. In addition, this review also discusses the use of microgravity technology to generate physiologically relevant human tissue models for research in bacterial pathogenesis.
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Affiliation(s)
- Cheryl A Nickerson
- Program in Molecular Pathogenesis and Immunity, Department of Microbiology and Immunology, SL 38, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
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