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Wang G, Mitomo H, Matsuo Y, Niikura K, Maeda M, Ijiro K. DNA-modulated photo-transformation of AgCl to silver nanoparticles: visiting the formation mechanism. J Colloid Interface Sci 2015; 452:224-234. [PMID: 25957236 DOI: 10.1016/j.jcis.2015.04.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 04/10/2015] [Indexed: 11/17/2022]
Abstract
Solution-phase synthesis and post-synthetic bio-modification have continued to play a dominant role in preparation of nanostructured biomaterials. Heterogeneous nucleation and growth that occur much more often in nature, however, remain rarely explored in nano-biomaterials research. We have newly developed a DNA-modulated photoconversion approach to uniform silver nanoparticles that afford DNA-directed recognition and multi-mode imaging. The present study was aimed at understanding the rapid heterogeneous nucleation and growth of AgNPs at the solid-liquid interface with the aid of DNA. Dynamic changes in absorbance, size and morphology of silver nanostructures were monitored and analyzed to clarify the growth kinetics, which indicated a synthetic route involving synchronous growth of silver nanostructures and the fragmentation and consumption of AgCl. Various stabilizers, including polymer and amino acids, were assessed and compared with respect to the efficacy in photoconversion of AgCl. DNA was found to offer the best monodispersity and the smallest diameter for the resultant AgNPs, due to its strong interactions to silver species as well as excellent charge dispersion ability. By controlling the physicochemical property of DNA through choice of pH and ionic strength, we have demonstrated tunable structure and composition of the nanoparticles.
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Affiliation(s)
- Guoqing Wang
- Research Institute for Electronic Science, Hokkaido University, Kita21, Nishi10, Kita-Ku, Sapporo 001-0021, Japan; Bioengineering Laboratory, RIKEN, 2-1 Hirosawa Wako, Saitama 351-0198, Japan
| | - Hideyuki Mitomo
- Research Institute for Electronic Science, Hokkaido University, Kita21, Nishi10, Kita-Ku, Sapporo 001-0021, Japan; JST-CREST, Sanban-Cho 5, Chiyoda-Ku, Japan
| | - Yasutaka Matsuo
- Research Institute for Electronic Science, Hokkaido University, Kita21, Nishi10, Kita-Ku, Sapporo 001-0021, Japan; JST-CREST, Sanban-Cho 5, Chiyoda-Ku, Japan
| | - Kenichi Niikura
- Research Institute for Electronic Science, Hokkaido University, Kita21, Nishi10, Kita-Ku, Sapporo 001-0021, Japan; JST-CREST, Sanban-Cho 5, Chiyoda-Ku, Japan
| | - Mizuo Maeda
- Bioengineering Laboratory, RIKEN, 2-1 Hirosawa Wako, Saitama 351-0198, Japan
| | - Kuniharu Ijiro
- Research Institute for Electronic Science, Hokkaido University, Kita21, Nishi10, Kita-Ku, Sapporo 001-0021, Japan; JST-CREST, Sanban-Cho 5, Chiyoda-Ku, Japan.
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Kamanda Ngugi D, Blom J, Alam I, Rashid M, Ba-Alawi W, Zhang G, Hikmawan T, Guan Y, Antunes A, Siam R, El Dorry H, Bajic V, Stingl U. Comparative genomics reveals adaptations of a halotolerant thaumarchaeon in the interfaces of brine pools in the Red Sea. THE ISME JOURNAL 2015; 9:396-411. [PMID: 25105904 PMCID: PMC4303633 DOI: 10.1038/ismej.2014.137] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 05/29/2014] [Accepted: 06/21/2014] [Indexed: 02/05/2023]
Abstract
The bottom of the Red Sea harbors over 25 deep hypersaline anoxic basins that are geochemically distinct and characterized by vertical gradients of extreme physicochemical conditions. Because of strong changes in density, particulate and microbial debris get entrapped in the brine-seawater interface (BSI), resulting in increased dissolved organic carbon, reduced dissolved oxygen toward the brines and enhanced microbial activities in the BSI. These features coupled with the deep-sea prevalence of ammonia-oxidizing archaea (AOA) in the global ocean make the BSI a suitable environment for studying the osmotic adaptations and ecology of these important players in the marine nitrogen cycle. Using phylogenomic-based approaches, we show that the local archaeal community of five different BSI habitats (with up to 18.2% salinity) is composed mostly of a single, highly abundant Nitrosopumilus-like phylotype that is phylogenetically distinct from the bathypelagic thaumarchaea; ammonia-oxidizing bacteria were absent. The composite genome of this novel Nitrosopumilus-like subpopulation (RSA3) co-assembled from multiple single-cell amplified genomes (SAGs) from one such BSI habitat further revealed that it shares ∼54% of its predicted genomic inventory with sequenced Nitrosopumilus species. RSA3 also carries several, albeit variable gene sets that further illuminate the phylogenetic diversity and metabolic plasticity of this genus. Specifically, it encodes for a putative proline-glutamate 'switch' with a potential role in osmotolerance and indirect impact on carbon and energy flows. Metagenomic fragment recruitment analyses against the composite RSA3 genome, Nitrosopumilus maritimus, and SAGs of mesopelagic thaumarchaea also reiterate the divergence of the BSI genotypes from other AOA.
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Affiliation(s)
- David Kamanda Ngugi
- Red Sea Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus Liebig University, Giessen, Germany
| | - Intikhab Alam
- Computational Bioscience Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Mamoon Rashid
- Red Sea Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Wail Ba-Alawi
- Computational Bioscience Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Guishan Zhang
- Red Sea Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Tyas Hikmawan
- Red Sea Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Yue Guan
- Red Sea Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Andre Antunes
- Red Sea Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Rania Siam
- Department of Biology, American University in Cairo, Cairo, Egypt
| | - Hamza El Dorry
- Department of Biology, American University in Cairo, Cairo, Egypt
| | - Vladimir Bajic
- Computational Bioscience Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Ulrich Stingl
- Red Sea Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
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