101
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Wang B, Shao Y, Chen T, Chen W, Chen F. Global insights into acetic acid resistance mechanisms and genetic stability of Acetobacter pasteurianus strains by comparative genomics. Sci Rep 2015; 5:18330. [PMID: 26691589 PMCID: PMC4686929 DOI: 10.1038/srep18330] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 11/16/2015] [Indexed: 12/11/2022] Open
Abstract
Acetobacter pasteurianus (Ap) CICC 20001 and CGMCC 1.41 are two acetic acid bacteria strains that, because of their strong abilities to produce and tolerate high concentrations of acetic acid, have been widely used to brew vinegar in China. To globally understand the fermentation characteristics, acid-tolerant mechanisms and genetic stabilities, their genomes were sequenced. Genomic comparisons with 9 other sequenced Ap strains revealed that their chromosomes were evolutionarily conserved, whereas the plasmids were unique compared with other Ap strains. Analysis of the acid-tolerant metabolic pathway at the genomic level indicated that the metabolism of some amino acids and the known mechanisms of acetic acid tolerance, might collaboratively contribute to acetic acid resistance in Ap strains. The balance of instability factors and stability factors in the genomes of Ap CICC 20001 and CGMCC 1.41 strains might be the basis for their genetic stability, consistent with their stable industrial performances. These observations provide important insights into the acid resistance mechanism and the genetic stability of Ap strains and lay a foundation for future genetic manipulation and engineering of these two strains.
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Affiliation(s)
- Bin Wang
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, P. R. China
| | - Yanchun Shao
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, P. R. China
| | - Tao Chen
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, P. R. China
| | - Wanping Chen
- Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, P. R. China.,College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, P. R. China
| | - Fusheng Chen
- Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, P. R. China.,Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei University of Technology, Wuhan 430068, Hubei Province, P. R. China.,College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, P. R. China
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102
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Fernandez-Rodriguez J, Yang L, Gorochowski TE, Gordon DB, Voigt CA. Memory and Combinatorial Logic Based on DNA Inversions: Dynamics and Evolutionary Stability. ACS Synth Biol 2015; 4:1361-72. [PMID: 26548807 DOI: 10.1021/acssynbio.5b00170] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Genetic memory can be implemented using enzymes that catalyze DNA inversions, where each orientation corresponds to a "bit". Here, we use two DNA invertases (FimE and HbiF) that reorient DNA irreversibly between two states with opposite directionality. First, we construct memory that is set by FimE and reset by HbiF. Next, we build a NOT gate where the input promoter drives FimE and in the absence of signal the reverse state is maintained by the constitutive expression of HbiF. The gate requires ∼3 h to turn on and off. The evolutionary stabilities of these circuits are measured by passaging cells while cycling function. The memory switch is stable over 400 h (17 days, 14 state changes); however, the gate breaks after 54 h (>2 days) due to continuous invertase expression. Genome sequencing reveals that the circuit remains intact, but the host strain evolves to reduce invertase expression. This work highlights the need to evaluate the evolutionary robustness and failure modes of circuit designs, especially as more complex multigate circuits are implemented.
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Affiliation(s)
- Jesus Fernandez-Rodriguez
- Synthetic
Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Lei Yang
- Synthetic
Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Thomas E. Gorochowski
- Synthetic
Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - D. Benjamin Gordon
- Synthetic
Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Broad
Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
| | - Christopher A. Voigt
- Synthetic
Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Broad
Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
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103
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Zhang C, Tsoi R, You L. Addressing biological uncertainties in engineering gene circuits. Integr Biol (Camb) 2015; 8:456-64. [PMID: 26674800 DOI: 10.1039/c5ib00275c] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Synthetic biology has grown tremendously over the past fifteen years. It represents a new strategy to develop biological understanding and holds great promise for diverse practical applications. Engineering of a gene circuit typically involves computational design of the circuit, selection of circuit components, and test and optimization of circuit functions. A fundamental challenge in this process is the predictable control of circuit function due to multiple layers of biological uncertainties. These uncertainties can arise from different sources. We categorize these uncertainties into incomplete quantification of parts, interactions between heterologous components and the host, or stochastic dynamics of chemical reactions and outline potential design strategies to minimize or exploit them.
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Affiliation(s)
- Carolyn Zhang
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
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104
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Standage-Beier K, Zhang Q, Wang X. Targeted Large-Scale Deletion of Bacterial Genomes Using CRISPR-Nickases. ACS Synth Biol 2015; 4:1217-25. [PMID: 26451892 PMCID: PMC4655420 DOI: 10.1021/acssynbio.5b00132] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
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Programmable
CRISPR-Cas systems have augmented our ability to produce
precise genome manipulations. Here we demonstrate and characterize
the ability of CRISPR-Cas derived nickases to direct targeted recombination
of both small and large genomic regions flanked by repetitive elements
in Escherichia coli. While CRISPR directed double-stranded DNA breaks are highly lethal
in many bacteria, we show that CRISPR-guided nickase systems can be
programmed to make precise, nonlethal, single-stranded incisions in
targeted genomic regions. This induces recombination events and leads
to targeted deletion. We demonstrate that dual-targeted nicking enables
deletion of 36 and 97 Kb of the genome. Furthermore, multiplex targeting
enables deletion of 133 Kb, accounting for approximately 3% of the
entire E. coli genome. This technology provides a
framework for methods to manipulate bacterial genomes using CRISPR-nickase
systems. We envision this system working synergistically with preexisting
bacterial genome engineering methods.
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Affiliation(s)
- Kylie Standage-Beier
- School of Life Sciences, ‡School of Biological
and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287, United States
| | - Qi Zhang
- School of Life Sciences, ‡School of Biological
and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287, United States
| | - Xiao Wang
- School of Life Sciences, ‡School of Biological
and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287, United States
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