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Ren W, Ding Y, Gu L, Yan W, Wang C, Lyu M, Wang C, Wang S. Characterization and mechanism of the effects of Mg-Fe layered double hydroxide nanoparticles on a marine bacterium: new insights from genomic and transcriptional analyses. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:196. [PMID: 31428192 PMCID: PMC6696678 DOI: 10.1186/s13068-019-1528-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 07/12/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Layered double hydroxides (LDHs) have received widespread attention for their potential applications in catalysis, polymer nanocomposites, pharmaceuticals, and sensors. Here, the mechanism underlying the physiological effects of Mg-Fe layered double hydroxide nanoparticles on the marine bacterial species Arthrobacter oxidans KQ11 was investigated. RESULTS Increased yields of marine dextranase (Aodex) were obtained by exposing A. oxidans KQ11 to Mg-Fe layered double hydroxide nanoparticles (Mg-Fe-LDH NPs). Furthermore, the potential effects of Mg-Fe-LDH NPs on bacterial growth and Aodex production were preliminarily investigated. A. oxidans KQ11 growth was not affected by exposure to the Mg-Fe-LDH NPs. In contrast, a U-shaped trend of Aodex production was observed after exposure to NPs at a concentration of 10 μg/L-100 mg/L, which was due to competition between Mg-Fe-LDH NP adsorption on Aodex and the promotion of Aodex expression by the NPs. The mechanism underling the effects of Mg-Fe-LDH NPs on A. oxidans KQ11 was investigated using a combination of physiological characterization, genomics, and transcriptomics. Exposure to 100 mg/L of Mg-Fe-LDH NPs led to NP adsorption onto Aodex, increased expression of Aodex, and generation of a new Shine-Dalgarno sequence (GGGAG) and sRNAs that both influenced the expression of Aodex. Moreover, the expressions of transcripts related to ferric iron metabolic functions were significantly influenced by treatment. CONCLUSIONS These results provide valuable information for further investigation of the A. oxidans KQ11 response to Mg-Fe-LDH NPs and will aid in achieving improved marine dextranase production, and even improve such activities in other marine microorganisms.
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Affiliation(s)
- Wei Ren
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
- Jiangsu Provincial Key Laboratory of Marine Biology, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095 Jiangsu People’s Republic of China
| | - Yanshuai Ding
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
| | - Lide Gu
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
| | - Wanli Yan
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
| | - Cang Wang
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
| | - Mingsheng Lyu
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
- Collaborative Innovation Center of Modern Bio-manufacture, Anhui University, Hefei, 230039 Anhui People’s Republic of China
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
| | - Changhai Wang
- Jiangsu Provincial Key Laboratory of Marine Biology, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095 Jiangsu People’s Republic of China
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
| | - Shujun Wang
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
- Collaborative Innovation Center of Modern Bio-manufacture, Anhui University, Hefei, 230039 Anhui People’s Republic of China
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005 Jiangsu People’s Republic of China
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Ghodke H, Paudel BP, Lewis JS, Jergic S, Gopal K, Romero ZJ, Wood EA, Woodgate R, Cox MM, van Oijen AM. Spatial and temporal organization of RecA in the Escherichia coli DNA-damage response. eLife 2019; 8:42761. [PMID: 30717823 PMCID: PMC6363387 DOI: 10.7554/elife.42761] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 01/22/2019] [Indexed: 12/14/2022] Open
Abstract
The RecA protein orchestrates the cellular response to DNA damage via its multiple roles in the bacterial SOS response. Lack of tools that provide unambiguous access to the various RecA states within the cell have prevented understanding of the spatial and temporal changes in RecA structure/function that underlie control of the damage response. Here, we develop a monomeric C-terminal fragment of the λ repressor as a novel fluorescent probe that specifically interacts with RecA filaments on single-stranded DNA (RecA*). Single-molecule imaging techniques in live cells demonstrate that RecA is largely sequestered in storage structures during normal metabolism. Upon DNA damage, the storage structures dissolve and the cytosolic pool of RecA rapidly nucleates to form early SOS-signaling complexes, maturing into DNA-bound RecA bundles at later time points. Both before and after SOS induction, RecA* largely appears at locations distal from replisomes. Upon completion of repair, RecA storage structures reform.
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Affiliation(s)
- Harshad Ghodke
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Bishnu P Paudel
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Jacob S Lewis
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Slobodan Jergic
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Kamya Gopal
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Zachary J Romero
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Elizabeth A Wood
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Roger Woodgate
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
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Staphylococcal pathogenicity island interference with helper phage reproduction is a paradigm of molecular parasitism. Proc Natl Acad Sci U S A 2012; 109:16300-5. [PMID: 22991467 DOI: 10.1073/pnas.1204615109] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Staphylococcal pathogenicity islands (SaPIs) carry superantigen and resistance genes and are extremely widespread in Staphylococcus aureus and in other Gram-positive bacteria. SaPIs represent a major source of intrageneric horizontal gene transfer and a stealth conduit for intergeneric gene transfer; they are phage satellites that exploit the life cycle of their temperate helper phages with elegant precision to enable their rapid replication and promiscuous spread. SaPIs also interfere with helper phage reproduction, blocking plaque formation, sharply reducing burst size and enhancing the survival of host cells following phage infection. Here, we show that SaPIs use several different strategies for phage interference, presumably the result of convergent evolution. One strategy, not described previously in the bacteriophage microcosm, involves a SaPI-encoded protein that directly and specifically interferes with phage DNA packaging by blocking the phage terminase small subunit. Another strategy involves interference with phage reproduction by diversion of the vast majority of virion proteins to the formation of SaPI-specific small infectious particles. Several SaPIs use both of these strategies, and at least one uses neither but possesses a third. Our studies illuminate a key feature of the evolutionary strategy of these mobile genetic elements, in addition to their carriage of important genes-interference with helper phage reproduction, which could ensure their transferability and long-term persistence.
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Meyer JD, Hanagan A, Manning MC, Catalano CE. The phage lambda terminase enzyme: 1. Reconstitution of the holoenzyme from the individual subunits enhances the thermal stability of the small subunit. Int J Biol Macromol 1998; 23:27-36. [PMID: 9644594 DOI: 10.1016/s0141-8130(98)00009-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The terminase enzyme from bacteriophage lambda is a hetero-trimeric complex composed of the viral gpA and gpNu1 proteins (gpA1.gpNu1(2)) and is responsible for packaging a single genome within the viral capsid. Current expression systems for these proteins require thermal induction which may be responsible for the formation of insoluble aggregates observed in E. coli. We report the re-cloning of the terminase subunits into vectors which allow low temperature induction. While this has resulted in increased solubility of the large gpA subunit of the enzyme, the small gpNu1 subunit remains insoluble under all conditions examined. This paper describes the solublization of gpNu1 with guanidinium hydrochloride and purification of the protein to homogeneity. Reconstitution of the enzyme from the individually purified subunits yields a catalytically-competent complex which exhibits activity identical to wild-type enzyme. Thermal denaturation of the proteins was monitored by circular dichroism (CD) spectroscopy and demonstrates that while unfolding of gpA is irreversible, the gpNu1 subunit refolds into a conformation which is essentially identical to the pre-heated protein. Moreover, while denaturation of gpA is highly cooperative, the small subunit unfolds over a wide temperature range and with thermodynamic parameters lower than expected for a small globular protein. Thermally-induced denaturation of the enzyme reconstituted from the individual subunits is highly cooperative with no evidence of multiple transitions. Our data demonstrate that the terminase subunits directly interact in solution, and that this interaction alters the thermal stability of the smaller gpNu1 subunit. The implication of these results with respect to assembly of a catalytically competent enzyme complex are discussed.
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Affiliation(s)
- J D Meyer
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Health Sciences Center, Denver 80262, USA
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Chai S, Szepan U, Alonso JC. Bacillus subtilis bacteriophage SPP1 terminase has a dual activity: it is required for the packaging initiation and represses its own synthesis. Gene 1997; 184:251-6. [PMID: 9031636 DOI: 10.1016/s0378-1119(96)00609-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The B. subtilis bacteriophage SPP1 terminase, encoded by genes 1 and 2, is required for the initiation of headful packaging. The DNA segment to which gene 1 product (G/P) binds includes the pacL and pacR sites and the late PL1 and PL2 promoters from which genes 1 to 7 are transcribed. When SPP1wt or SPP1sus115 (gene 6-) phages were used to infect a B. subtilis sup0 strain, the gene 1 to 7 mRNA synthesis was reduced at late times of infection. This was not observed, however, when either chloramphenicol was added 7 min after infection with SPP1wt or when SPP1sus114 (gene 1-) or SPP1sus19 (gene 2-) were used to infect B. subtilis sup0 cells. These results suggest that the terminase enzyme functions as a repressor of its own transcription. G/P and B. subtilis RNA polymerase (RP) bind to the pacL segment, which contains the PL1 and PL2 promoter region. The binding of G/P to the pacL site does not seem to exclude RP from the promoters, despite of the overlapping of their binding sites. It is likely that the terminase protein does not repress transcription by a mere steric hindrance of RP binding.
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Affiliation(s)
- S Chai
- Centro Nacional de Biotecnología, CSIC, Madrid, Spain
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Parris W, Rubinchik S, Yang Y, Gold M. A new procedure for the purification of the bacteriophage lambda terminase enzyme and its subunits. Properties of gene product A, the large subunit. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36868-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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