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Carpenter MA, Pesquera D, O'Flynn D, Balakrishnan G, Mufti N, Nugroho AA, Palstra TTM, Mihalik M, Mihalik M, Zentková M, Almeida A, Moreira JA, Vilarinho R, Meier D. Strain relaxation dynamics of multiferroic orthorhombic manganites. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:125402. [PMID: 33007773 DOI: 10.1088/1361-648x/abbdba] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 10/02/2020] [Indexed: 06/11/2023]
Abstract
Resonant ultrasound spectroscopy has been used to characterise strain coupling and relaxation behavior associated with magnetic/magnetoelectric phase transitions in GdMnO3, TbMnO3and TbMn0.98Fe0.02O3through their influence on elastic/anelastic properties. Acoustic attenuation ahead of the paramagnetic to colinear-sinusoidal incommensurate antiferromagnetic transition at ∼41 K correlates with anomalies in dielectric properties and is interpreted in terms of Debye-like freezing processes. A loss peak at ∼150 K is related to a steep increase in electrical conductivity with a polaron mechanism. The activation energy,Ea, of ≳0.04 eV from a loss peak at ∼80 K is consistent with the existence of a well-defined temperature interval in which the paramagnetic structure is stabilised by local, dynamic correlations of electric and magnetic polarisation that couple with strain and have relaxation times in the vicinity of ∼10-6s. Comparison with previously published data for Sm0.6Y0.4MnO3confirms that this pattern may be typical for multiferroic orthorhombicRMnO3perovskites (R= Gd, Tb, Dy). A frequency-dependent loss peak near 10 K observed for TbMnO3and TbMn0.98Fe0.02O3, but not for GdMnO3, yieldedEa⩾ ∼0.002 eV and is interpreted as freezing of some magnetoelastic component of the cycloid structure. Small anomalies in elastic properties associated with the incommensurate and cycloidal magnetic transitions confirm results from thermal expansion data that the magnetic order parameters have weak but significant coupling with strain. Even at strain magnitudes of ∼0.1-1‰, polaron-like strain effects are clearly important in defining the development and evolution of magnetoelectric properties in these materials. Strains associated with the cubic-orthorhombic transition due to the combined Jahn-Teller/octahedral tilting transition in the vicinity of 1500 K are 2-3 orders of magnitude greater. It is inevitable that ferroelastic twin walls due to this transition would have significantly different magnetoelectric properties from homogeneous domains due to magnetoelastic coupling with steep strain gradients.
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Affiliation(s)
- M A Carpenter
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
| | - D Pesquera
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
| | - D O'Flynn
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - G Balakrishnan
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - N Mufti
- Solid State Chemistry Laboratory, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
- Department of Physics, Universitas Negeri Malang, Jl. Semarang No.5, Malang, 65145 Indonesia, Indonesia
| | - A A Nugroho
- Solid State Chemistry Laboratory, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - T T M Palstra
- Solid State Chemistry Laboratory, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - M Mihalik
- Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, Košice, Slovakia
| | - M Mihalik
- Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, Košice, Slovakia
| | - M Zentková
- Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, Košice, Slovakia
| | - A Almeida
- IFIMUP, Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal
| | - J Agostinho Moreira
- IFIMUP, Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal
| | - R Vilarinho
- IFIMUP, Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal
| | - D Meier
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, 7491 Trondheim, Norway
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Non-collinear magnetism & multiferroicity: the perovskite case. PHYSICAL SCIENCES REVIEWS 2021. [DOI: 10.1515/psr-2019-0071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The most important types of non-collinear magnetic orders that are realized in simple perovskite oxides are outlined in relation to multiferroicity. These orders are classified and rationalized in terms of a mimimal spin Hamiltonian, based on which the notion of spin-driven ferroelectricity is illustrated. These concepts find direct application in reference materials such as BiFeO3, GdFeO3 and TbMnO3 whose multiferroic properties are briefly reviewed.
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Study of gadolinium substitution effects in hexagonal yttrium manganite YMnO 3. Sci Rep 2021; 11:2875. [PMID: 33536490 PMCID: PMC7859184 DOI: 10.1038/s41598-021-82621-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/21/2021] [Indexed: 01/30/2023] Open
Abstract
In the present work, gadolinium substitution effects on the properties of yttrium manganite YxGd1-xMn0.97Fe0.03O3 (x from 0 to 1 with a step of 0.2) synthesized by an aqueous sol-gel method have been investigated. Partial substitution of Mn3+ by 57Fe3+ in the manganite was also performed in order to investigate deeper the structural properties of synthesized compounds applying Mössbauer spectroscopy. It was demonstrated that substitution of Y3+ by Gd3+ ions leads to the changes of structural, magnetic and morphological properties of investigated system. The crystal structure gradually transformed from hexagonal to orthorhombic with an increase of Gd3+ content in the crystal lattice. The mixed phase was obtained when x = 0.6, whereas other compounds were determined to be monophasic. Magnetization measurements revealed paramagnetic behavior of all specimens, however magnetization values were found to be dependent on chemical composition of the samples. Solid solutions with orthorhombic structure revealed higher magnetization values compared to those of hexagonal samples. The highest magnetization was observed for pure GdMn0.97Fe0.03O3. Structural properties were investigated by powder X-ray diffraction, Mössbauer, FTIR and Raman spectroscopies. Morphological features of the synthesized specimens were studied by scanning electron microscopy (SEM).
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Gagné OC, Hawthorne FC. Bond-length distributions for ions bonded to oxygen: results for the transition metals and quantification of the factors underlying bond-length variation in inorganic solids. IUCRJ 2020; 7:581-629. [PMID: 32695408 PMCID: PMC7340253 DOI: 10.1107/s2052252520005928] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 04/29/2020] [Indexed: 06/01/2023]
Abstract
Bond-length distributions are examined for 63 transition metal ions bonded to O2- in 147 configurations, for 7522 coordination polyhedra and 41 488 bond distances, providing baseline statistical knowledge of bond lengths for transition metals bonded to O2-. A priori bond valences are calculated for 140 crystal structures containing 266 coordination polyhedra for 85 transition metal ion configurations with anomalous bond-length distributions. Two new indices, Δtopol and Δcryst, are proposed to quantify bond-length variation arising from bond-topological and crystallographic effects in extended solids. Bond-topological mechanisms of bond-length variation are (1) non-local bond-topological asymmetry and (2) multiple-bond formation; crystallographic mechanisms are (3) electronic effects (with an inherent focus on coupled electronic vibrational degeneracy in this work) and (4) crystal-structure effects. The indices Δtopol and Δcryst allow one to determine the primary cause(s) of bond-length variation for individual coordination polyhedra and ion configurations, quantify the distorting power of cations via electronic effects (by subtracting the bond-topological contribution to bond-length variation), set expectation limits regarding the extent to which functional properties linked to bond-length variation may be optimized in a given crystal structure (and inform how optimization may be achieved) and more. These indices further provide an equal footing for comparing bond-length variation and the distorting power of ions across ligand types, including resolution for heteroligand polyhedra. The observation of multiple bonds is found to be primarily driven by the bond-topological requirements of crystal structures in solids. However, sometimes multiple bonds are observed to form as a result of electronic effects (e.g. the pseudo Jahn-Teller effect, PJTE); resolution of the origins of multiple-bond formation follows calculation of the Δtopol and Δcryst indices on a structure-by-structure basis. Non-local bond-topological asymmetry is the most common cause of bond-length variation in transition metal oxides and oxysalts, followed closely by the PJTE. Non-local bond-topological asymmetry is further suggested to be the most widespread cause of bond-length variation in the solid state, with no a priori limitations with regard to ion identity. Overall, bond-length variations resulting from the PJTE are slightly larger than those resulting from non-local bond-topological asymmetry, comparable with those resulting from the strong JTE, and less than those induced by π-bond formation. From a comparison of a priori and observed bond valences for ∼150 coordination polyhedra in which the strong JTE or the PJTE is the main reason underlying bond-length variation, the JTE is found not to have a cooperative relation with the bond-topological requirements of crystal structures. The magnitude of bond-length variation caused by the PJTE decreases in the following order for octahedrally coordinated d 0 transition metal oxyanions: Os8+ > Mo6+ > W6+ >> V5+ > Nb5+ > Ti4+ > Ta5+ > Hf4+ > Zr4+ > Re7+ >> Y3+ > Sc3+. Such ranking varies by coordination number; for [4] it is Re7+ > Ti4+ > V5+ > W6+ > Mo6+ > Cr6+ > Os8+ >> Mn7+; for [5] it is Os8+ > Re7+ > Mo6+ > Ti4+ > W6+ > V5+ > Nb5+. It is concluded that non-octahedral coordinations of d 0 ion configurations are likely to occur with bond-length variations that are similar in magnitude to their octahedral counterparts. However, smaller bond-length variations are expected from the PJTE for non-d 0 transition metal oxyanions.
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Affiliation(s)
- Olivier Charles Gagné
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, D.C. 20015, USA
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Machado P, Figueiras F, Vilarinho R, Fernandes J, Tavares P, Rosário Soares M, Cardoso S, Almeida A, Agostinho Moreira J. Orthorhombic GdMnO 3 Epitaxial Thin Film Grown onto SrTiO 3 (110). EPJ WEB OF CONFERENCES 2020. [DOI: 10.1051/epjconf/202023305005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
GdMnO3 epitaxial thin films were deposited onto (110)-oriented SrTiO3 substrates by RF magnetron sputtering. The structure, microstructure, dielectric and magnetic properties were investigated in detail. The XRD results revealed that the GdMnO3 thin films exhibit an epitaxial strained orthorhombic symmetry and grow preferably in off-plane (001) orientation, wherein the basal lattice parameters are strained by the substrate lattice. A dielectric relaxation process was ascertained, whose activation energy is sensitive to the magnetic phase transitions, occurring at 41 K and at 20 K, respectively. The canted nature of the low temperature magnetic phase is discussed.
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Strain-Engineered Tetragonal Phase and Ferroelectricity in GdMnO 3 Thin Films Grown on SrTiO 3 (001). Sci Rep 2019; 9:18755. [PMID: 31822738 PMCID: PMC6904445 DOI: 10.1038/s41598-019-55227-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 11/04/2019] [Indexed: 11/25/2022] Open
Abstract
A previously unreported tetragonal phase has been discovered in a epitaxially strained GdMnO3 thin films deposited on (001)-oriented SrTiO3 substrates by radio frequency (RF) magnetron sputtering. The tetragonal axis of the films grown up to a 35 nm thickness is perpendicular to the film surface and the basal lattice parameters are imposed by the cubic structure of the substrate. Furthermore, the emergence of a spontaneous electric polarization below ~32 K points to the stabilization of an improper ferroelectric phase at low temperatures, which is not observed in bulk GdMnO3. This work shows how strain engineering can be used to tailor the structure and properties of strongly correlated oxides.
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Lu C, Wu M, Lin L, Liu JM. Single-phase multiferroics: new materials, phenomena, and physics. Natl Sci Rev 2019; 6:653-668. [PMID: 34691921 PMCID: PMC8291614 DOI: 10.1093/nsr/nwz091] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/15/2019] [Accepted: 06/20/2019] [Indexed: 12/23/2022] Open
Abstract
Multiferroics, where multiple ferroic orders coexist and are intimately coupled, promise novel applications in conceptually new devices on one hand, and on the other hand provide fascinating physics that is distinctly different from the physics of high-TC superconductors and colossal magnetoresistance manganites. In this mini-review, we highlight the recent progress of single-phase multiferroics in the exploration of new materials, efficient roadmaps for functionality enhancement, new phenomena beyond magnetoelectric coupling, and underlying novel physics. In the meantime, a slightly more detailed description is given of several multiferroics with ferrimagnetic orders and double-layered perovskite structure and also of recently emerging 2D multiferroics. Some emergent phenomena such as topological vortex domain structure, non-reciprocal response, and hybrid mechanisms for multiferroicity engineering and magnetoelectric coupling in various types of multiferroics will be briefly reviewed.
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Affiliation(s)
- Chengliang Lu
- School of Physics & Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Menghao Wu
- School of Physics & Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Lin Lin
- Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
| | - Jun-Ming Liu
- Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
- Institute for Advanced Materials, Hubei Normal University, Huangshi 435002, China
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Bousquet E, Cano A. Non-collinear magnetism in multiferroic perovskites. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:123001. [PMID: 26912212 DOI: 10.1088/0953-8984/28/12/123001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present an overview of the current interest in non-collinear magnetism in multiferroic perovskite crystals. We first describe the different microscopic mechanisms giving rise to the non-collinearity of spins in this class of materials. We discuss, in particular, the interplay between non-collinear magnetism and ferroelectric and antiferrodistortive distortions of the perovskite structure, and how this can promote magnetoelectric responses. We then provide a literature survey on non-collinear multiferroic perovskites. We discuss numerous examples of spin cantings driving weak ferromagnetism in transition metal perovskites, and of spin-induced ferroelectricity as observed in the rare-earth based perovskites. These examples are chosen to best illustrate the fundamental role of non-collinear magnetism in the design of multiferroicity.
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Affiliation(s)
- Eric Bousquet
- Physique Théorique des Matériaux, Université de Liège, B-4000 Sart Tilman, Belgium
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Lu C, Deniz H, Li X, Liu JM, Cheong SW. Continuous Magnetoelectric Control in Multiferroic DyMnO3 Films with Twin-like Domains. Sci Rep 2016; 6:20175. [PMID: 26829899 PMCID: PMC4735850 DOI: 10.1038/srep20175] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 12/23/2015] [Indexed: 11/26/2022] Open
Abstract
The magnetic control of ferroelectric polarization is currently a central topic in the multiferroic researches, owing to the related gigantic magnetoelectric coupling and fascinating physics. Although a bunch of novel magnetoelectric effect have been discovered in multiferroics of magnetic origin, the manipulation of polarization was found to be fundamentally determined by the microscopic origin in a certain multiferroic phase, hindering the development of unusual magnetoelectric control. Here, we report emergent magnetoelectric control in DyMnO3/Nb:SrTiO3 (001) films showing twin-like domain structure. Our results demonstrate interesting magnetically induced partial switch of polarization due to the coexistence of polarizations along both the a-axis and c-axis enabled by the twin-like domain structure in DyMnO3 films, despite the polarization-switch was conventionally believed to be a one-step event in the bulk counterpart. Moreover, a continuous and periodic control of macroscopic polarization by an in-plane rotating magnetic field is evidenced in the thin films. This distinctive magnetic manipulation of polarization is the consequence of the cooperative action of the twin-like domains and the dual magnetic origin of polarization, which promises additional applications using the magnetic control of ferroelectricity.
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Affiliation(s)
- Chengliang Lu
- School of Physics &Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China.,Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Saale), Germany
| | - Hakan Deniz
- Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Saale), Germany
| | - Xiang Li
- Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jun-Ming Liu
- Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey, 08854, USA.,Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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Nandy A, Roychowdhury A, Kar T, Das D, Pradhan SK. Effect of sodium doping on the microstructure, lattice distortion and magnetic properties of GdMnO3 tiny single crystals. RSC Adv 2016. [DOI: 10.1039/c5ra19631k] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
10% monovalent sodium doping reduces the octahedral and lattice distortion in GdMnO3 tiny single crystals and introduces ferromagnetic ordering in the compound.
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Affiliation(s)
- Anshuman Nandy
- Department of Physics
- The University of Burdwan
- Burdwan-713104
- India
| | - Anirban Roychowdhury
- UGC-DAE Consortium for Scientific Research
- Kolkata-700098
- India
- Department of Physics
- Krishnath College
| | - Tanushree Kar
- Indian Association for Cultivation of Science
- Kolkata-700032
- India
| | - Dipankar Das
- UGC-DAE Consortium for Scientific Research
- Kolkata-700098
- India
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Hu N, Lu C, Xia Z, Xiong R, Fang P, Shi J, Liu JM. Multiferroicity and Magnetoelectric Coupling in TbMnO3 Thin Films. ACS APPLIED MATERIALS & INTERFACES 2015; 7:26603-26607. [PMID: 26573085 DOI: 10.1021/acsami.5b08091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this work, we report the growth and functional characterizations of multiferroic TbMnO3 thin films grown on Nb-doped SrTiO3 (001) substrates using pulsed laser deposition. By performing detailed magnetic and ferroelectric properties measurements, we demonstrate that the multiferroicity of spin origin known in the bulk crystals can be successfully transferred to TbMnO3 thin films. Meanwhile, anomalous magnetic transition and unusual magnetoelectric coupling related to Tb moments are observed, suggesting a modified magnetic configuration of Tb in the films as compared to the bulk counterpart. In addition, it is found that the magnetoelectric coupling enabled by Tb moments can even be seen far above the Tb spin ordering temperature, which provides a larger temperature range for the magnetoelectric control involving Tb moments.
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Affiliation(s)
- Ni Hu
- Department of Physics, Wuhan University , Wuhan 430072, China
- School of Science and Hubei Collaborative Innovation Center for High-Efficiency Utilization of Solar Energy, Hubei University of Technology , Wuhan 430068, China
| | - Chengliang Lu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology , Wuhan 430074, China
| | - Zhengcai Xia
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology , Wuhan 430074, China
| | - Rui Xiong
- Department of Physics, Wuhan University , Wuhan 430072, China
| | - Pengfei Fang
- Department of Physics, Wuhan University , Wuhan 430072, China
| | - Jing Shi
- Department of Physics, Wuhan University , Wuhan 430072, China
| | - Jun-Ming Liu
- Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, China
- Institute for Quantum Materials, Hubei Polytechnic University , Huangshi 435000, China
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Li X, Huang S, Ren Y, Wang M, Kang C, Xie L, Shi D. Establishment of a mouse model to express bovine CD14 short hairpin RNA. BMC Vet Res 2015; 11:36. [PMID: 25889660 PMCID: PMC4332730 DOI: 10.1186/s12917-015-0353-5] [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: 06/10/2014] [Accepted: 02/06/2015] [Indexed: 11/25/2022] Open
Abstract
Background Cluster of differentiation 14 (CD14) functions as a co-receptor for Toll-like receptor (TLR)-4 and myeloid differentiation factor (MD)-2 in detecting bacterial lipopolysaccharide. Together, these complexes promote the phagocytosis and digestion of Gram-negative bacteria, and initiate immune responses. To date, much of our understanding of CD14 function during Gram-negative bacterial inflammation comes from studies on mouse knockout models and cell transfection. To identify the effect of CD14 knockdown in this process in large livestock animals, we established a mouse model expressing bovine CD14 short hairpin (sh) RNA. shRNA fragments targeting bovine CD14 were screened by co-transfection in HEK 293 cells, and the most effective CD14 shRNA fragment was cloned into the eukaryotic expression vector pSilencer4.1-CD14 shRNA-IRES (internal ribosome entry site) and transferred into mouse zygotes by pronuclear microinjection to obtain transgenic mice. Expression of the enhanced green fluorescent protein (EGFP) reporter and genes related to the TLR4 signaling pathway was detected by immunohistochemistry (IHC) and quantitative polymerase chain reaction (PCR), respectively. Results One effective shRNA fragment (shRNA-674) targeting bovine CD14 was obtained, the sequence of which was shown to be conserved between cows, buffalos, sheep, and humans. Thirty-seven founder pups were obtained by pronuclear microinjection, of which three were positive for the transgene. In the F1 generation, 11 of 33 mice (33%) were positive for the transgene as detected by PCR. IHC analysis detected exogenous EGFP expression in the liver, kidney, and spleen of transgenic F1 mice, indicating that they were chimeric. The expression of endogenous CD14 mRNA in the heart, liver, spleen, lung, and kidney of transgenic F1 mice was decreased 8-, 3-, 19.5-, 6-, and 11-fold, respectively. The expression patterns of endogenous MD-2, TLR4, interleukin-6 and tumor necrosis factor-α genes in transgenic mice also varied. Conclusions This study confirms that transgenic mice expressing bovine CD14 shRNA can be generated by pronuclear microinjection, and demonstrates inhibited endogenous mouse CD14 expression that alters gene expression related to the TLR4 signaling pathway.
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Affiliation(s)
- Xiangping Li
- State Key Laboratory of Subtropical Bioresource Conservation and Utilization at Guangxi University, Nanning, Guangxi, China. .,Guangxi High Education Key Laboratory for Animal Reproduction and Biotechnology, Guangxi University, Nanning, 530004, China.
| | - Shihai Huang
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China.
| | - Yanping Ren
- State Key Laboratory of Subtropical Bioresource Conservation and Utilization at Guangxi University, Nanning, Guangxi, China. .,Guangxi High Education Key Laboratory for Animal Reproduction and Biotechnology, Guangxi University, Nanning, 530004, China.
| | - Meng Wang
- State Key Laboratory of Subtropical Bioresource Conservation and Utilization at Guangxi University, Nanning, Guangxi, China. .,Guangxi High Education Key Laboratory for Animal Reproduction and Biotechnology, Guangxi University, Nanning, 530004, China.
| | - Chao Kang
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China.
| | - Liangliang Xie
- State Key Laboratory of Subtropical Bioresource Conservation and Utilization at Guangxi University, Nanning, Guangxi, China. .,Guangxi High Education Key Laboratory for Animal Reproduction and Biotechnology, Guangxi University, Nanning, 530004, China.
| | - Deshun Shi
- State Key Laboratory of Subtropical Bioresource Conservation and Utilization at Guangxi University, Nanning, Guangxi, China. .,Guangxi High Education Key Laboratory for Animal Reproduction and Biotechnology, Guangxi University, Nanning, 530004, China.
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