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Wang J, Bai P, Li Q, Lin Y, Huo D, Ke F, Zhang Q, Li T, Zhao J. Interaction between cyanophage MaMV-DC and eight Microcystis strains, revealed by genetic defense systems. HARMFUL ALGAE 2019; 85:101699. [PMID: 31810530 DOI: 10.1016/j.hal.2019.101699] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 06/10/2023]
Abstract
Cyanophage MaMV-DC is a member of Myoviridae that was reported to specifically infect and lyse Microcystis aeruginosa FACHB-524 among 21 selected cyanobacterial strains. We reidentified the infection specificity of MaMV-DC among seven other Microcystis strains of different species. In our experiments, MaMV-DC infected three Microcystis strains but did not form plaque in Microcystis lawns. This indicated that MaMV-DC is at least a genus- rather than strain-specific virus. Cyanophage MaMV-DC genes were transcribed in M. aeruginosa FACHB-524, M. flos-aquae TF09, M. aeruginosa TA09 and M. wesenbergii DW09, and the growth of these Microcystis strains was inhibited by the addition of MaMV-DC. The predicted defense of eight Microcystis strains by CRISPR-Cas systems has shown mixed consistency with the infection experiment results, suggesting other defense or anti-defense systems play roles during infection process. Restriction-modification (RM) system analysis revealed an abundance of four types of RM proteins that may play roles in defense against cyanophages.
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Affiliation(s)
- Juanping Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan 430071, China
| | - Peng Bai
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qi Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Yan Lin
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Da Huo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fei Ke
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Qiya Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Tao Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Jindong Zhao
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; State Key Laboratory of Protein and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, China
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Péant B, LaPointe G. Identification and characterization of a conserved nuclease secreted by strains of the Lactobacillus casei group. J Appl Microbiol 2004; 96:367-74. [PMID: 14723698 DOI: 10.1046/j.1365-2672.2004.02160.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS Nuclease secretion was evaluated for five species of Lactobacillus and the activity was characterized in terms of thermal resistance, molecular weight and mode of action on plasmid DNA. METHODS AND RESULTS Assays of nuclease from L. rhamnosus ATCC 9595 on DNA of different origins indicates a broad activity spectrum. Secreted nuclease from this strain resists a thermal treatment of 20 min at 100 degrees C, is not sensitive to a treatment for disruption of disulphide bonds nor to EDTA treatment under 10 mM l(-1). Nuclease production is not growth linked and seems to be constitutive. Extracellular nuclease of L. rhamnosus ATCC 9595 introduces a single-stranded nick in supercoiled DNA, thus potentially reducing the transformability of plasmid DNA. In seven of eight tested strains, SDS-PAGE revealed a major protein with a molecular weight of ca 35 kDa. Minor degradation products also showed nuclease activity. CONCLUSIONS A comparative analysis of the extracellular fractions of 14 different Lactobacillus strains indicate that nuclease secretion seems to be a widely distributed function among species of milk-related lactobacilli. The production of secreted nuclease may contribute to the low ability of Lactobacillus spp. to be transformed and maintain exogenous DNA. SIGNIFICANCE AND IMPACT OF THE STUDY Determination of the characteristics and distribution of nuclease activity contribute to developing strategies to overcome this barrier to efficient transformation of milk lactobacilli.
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Affiliation(s)
- B Péant
- STELA Dairy Research Centre, Laval University, Quebec, Canada
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Cao J, Liang D, Xu Z, Qiu G, Li B, Vonshak A. Physico-chemical parameters influencing DNase activity of the cyanobacterium Spirulina platensis. Microbiol Res 2000; 155:59-63. [PMID: 10830902 DOI: 10.1016/s0944-5013(00)80024-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The effects of temperature, Mg2+, EDTA concentration and rinsing on extra- and intra-cellular DNase activity of Spirulina platensis strain SSP-14, were investigated. The results indicate that the tested strain contains very high extra- and intracellular DNase activity, which actually hinders the transfer of foreign gene(s) to S. platensis, a cyanobacterium with multiple economic potentials. The extracellular DNase activity could easily be removed by rinsing the cells with Zarrouk medium more than once. The intracellular DNase activity could also be inhibited by (1) removal of Mg2+, (2) maintaining EDTA concentration above 1 mmol l(-1), and (3) manipulating below 0-4 degrees C, during all the incubation procedures. We suggest that, by using one or more of, or combining, all those experimental conditions, the chances of foreign DNA attempted to be introduced into S. platensis without being digested would be increased.
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Affiliation(s)
- J Cao
- Marine Biotechnology Center, University of California, Santa Barbara 93106, USA.
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Tavares F, Sellstedt A. A simple, rapid and non-destructive procedure to extract cell wall-associated proteins from Frankia. J Microbiol Methods 2000; 39:171-8. [PMID: 10576707 DOI: 10.1016/s0167-7012(99)00115-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A simple cell fractionation procedure was developed to extract cell wall-associated proteins from the nitrogen-fixing actinomycete Frankia. The method was based on washing Frankia mycelia in 62.5 mM Tris-HCl (pH 6.8) buffer supplemented with 0.1% Triton X-100 as solubilizing agent. Cell wall-associated proteins were efficiently extracted in less than 10 min, recovering approximately 94.5+/-7.44 microg protein per extraction procedure from exponentially growing cells corresponding to 50 ml of culture. The amount of cell lysis occurring during the cell wall extraction was estimated to be 1.50+/-0.51%. Three peptidoglycan hydrolases with apparent molecular masses of 4.7, 12.1, and 17.8 kDa were detected by zymography in the cell wall-associated protein fraction. On the contrary, no cell wall lytic enzyme was detected in the cytoplasmic protein fraction. These results indicate that the present method enables a specific extraction of cell wall-associated proteins. Moreover, fluorescein isothiocyanate (FITC) labelling of the cell surface proteins showed an efficient removal of cell wall-associated proteins. Growth of the treated Frankia cells (i.e. cells from which the cell wall-associated proteins were removed) in semi-solid media suggested that these cells were still viable. This technique is of importance for functionality studies of cell wall-associated proteins, particularly for bacteria where traditional cell fractionation methods are difficult to be applied.
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Affiliation(s)
- F Tavares
- Institute of Botany, University of Porto, Portugal.
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Tavares F, Sellstedt A. DNase Activities of the Extracellular, Cell Wall-Associated, and Cytoplasmic Protein Fractions of Frankia Strain R43. Appl Environ Microbiol 1997; 63:4597-9. [PMID: 16535742 PMCID: PMC1389298 DOI: 10.1128/aem.63.11.4597-4599.1997] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
DNase activities in different protein fractions of Frankia strain R43 were studied. The extracellular and the cell wall-associated fractions revealed the presence of exo- and endonucleolytic enzymes, but none was detected in the cytoplasmic fraction. The strongest DNase hydrolysis was found in the extracellular fraction, in which six DNases were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
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Bradley RL, Reddy KJ. Cloning, sequencing, and regulation of the global nitrogen regulator gene ntcA in the unicellular diazotrophic cyanobacterium Cyanothece sp. strain BH68K. J Bacteriol 1997; 179:4407-10. [PMID: 9209062 PMCID: PMC179268 DOI: 10.1128/jb.179.13.4407-4410.1997] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In cyanobacteria, ammonium represses expression of proteins involved in nitrogen fixation and assimilation. The global nitrogen regulator gene ntcA encodes a DNA-binding protein, NtcA, that is a transcriptional activator of genes subject to nitrogen control. We report the cloning and sequencing of the ntcA gene from a nitrogen-fixing unicellular cyanobacterium, Cyanothece sp. strain BH68K. The gene comprises 678 nucleotides, and the deduced NtcA protein contains 226 amino acids with a predicted molecular weight of 25,026. In addition, ntcA mRNA levels were measured in cells grown under different nitrogen regimes. Under nitrogen-fixing conditions, ntcA transcripts were weakly expressed. Furthermore, ntcA expression was diminished or inversely proportional to nifHDK expression. Conversely, ntcA expression increased in nitrate-grown cells, and a concentration-dependent increase was seen in ammonium-grown cells up to 1 mM NH4Cl. These results indicate that ntcA is involved more in nitrogen assimilation than in nitrogen fixation and also imply that the rhythmic expression of ntcA and nifHDK transcription may be under the control of a circadian clock.
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Affiliation(s)
- R L Bradley
- Department of Biological Sciences, State University of New York at Binghamton, 13902, USA
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Takahashi I, Hayano D, Asayama M, Masahiro F, Watahiki M, Shirai M. Restriction barrier composed of an extracellular nuclease and restriction endonuclease in the unicellular cyanobacterium Microcystis sp. FEMS Microbiol Lett 1996; 145:107-11. [PMID: 8931334 DOI: 10.1111/j.1574-6968.1996.tb08564.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The unicellular cyanobacterium Microcystis aeruginosa K-81 has two types of restriction barrier, an extracellular nuclease and sequence-specific endonucleases. The nuclease was detected in the culture supernatant and it was easily released from the cells by washing with water or buffer containing Triton X-100. This nuclease was identified as a polypeptide of about 28 kDa that digested covalently closed circular and linear double-stranded DNAs, including chromosomal DNA from M. aeruginosa K-81. Among another 13 Microcystis strains examined, 3 produced an extracellular nuclease. Furthermore, M. aeruginosa K-81 contained two sequence-specific endonucleases, MaeK81I and MaeK81II, which were isoschizomers of SplI and Sau96I, respectively.
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Affiliation(s)
- I Takahashi
- Division of Biotechnology, School of Agriculture, Ibaraki University, Japan
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Reddy KJ, Soper BW, Tang J, Bradley RL. Phenotypic variation in exopolysaccharide production in the marine, aerobic nitrogen-fixing unicellular cyanobacterium Cyanothece sp. World J Microbiol Biotechnol 1996; 12:311-8. [DOI: 10.1007/bf00340206] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 01/26/1996] [Accepted: 03/19/1996] [Indexed: 10/26/2022]
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Asayama M, Kabasawa M, Takahashi I, Aida T, Shirai M. Highly repetitive sequences and characteristics of genomic DNA in unicellular cyanobacterial strains. FEMS Microbiol Lett 1996; 137:175-81. [PMID: 8998982 DOI: 10.1111/j.1574-6968.1996.tb08102.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Microcystis aeruginosa (Synechocystis) is a unicellular cyanobacterium that performs oxygenic photosynthesis. We found two novel sets of repetitive sequences, A (REP-A) and B (REP-B), on the M. aeruginosa K-81 genomic DNA, which consisted of distinct motifs of tandem repeated sequences located in the up- and downstream regions of the orf1 structural gene, respectively. Genomic Southern hybridization revealed multicopies of REP-A and -B on the genome. Furthermore, genomic Southern blots of cyanobacteria species with the REP-A and -B probes revealed that different hybridization signals appeared on the genomic DNAs of all 12 Microcystis strains, but no signal appeared on those of Synechocystis sp. PCC 6803, Synechococcus sp. PCC 7942, and Anabaena sp. PCC 7120.
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Affiliation(s)
- M Asayama
- Division of Biotechnology, School of Agriculture, Ibaraki University, Japan
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