Background： Brucella is a zoonotic Gram-negative pathogen that causes abortion and infertility in ruminants and humans. TLR4 is the receptor for LPS which can recognize Brucella and initiate antigen-presenting cell a...Background： Brucella is a zoonotic Gram-negative pathogen that causes abortion and infertility in ruminants and humans. TLR4 is the receptor for LPS which can recognize Brucella and initiate antigen-presenting cell activities that affect both innate and adaptive immunity. Consequently, transgenic sheep over-expressing TLR4 are an suitable model to investigate the effects of TLR4 on preventing Brucellosis. In this study, we generated transgenic sheep overexpressing TLR4 and aimed to evaluate the effects of different seasons（breeding and non-breeding season） on superovulation and the imported exogenous gene on growth.Results： In total of 43 donor ewes and 166 recipient ewes in breeding season, 37 donor ewes and 144 recipient ewes in non-breeding season were selected for super-ovulation and injected embryo transfer to generate transgenic sheep.Our results indicated the no. of embryos recovered of donors and the rate of pronuclear embryos did not show any significant difference between breeding and non-breeding seasons（P 〉 0.05）. The positive rate of exogenous TLR4 tested were 21.21 % and 22.58 % in breeding and non-breeding season by Southern blot. The expression level of TLR4 in the transgenic sheep was 1.5 times higher than in the non-transgenic group（P 〈 0.05）. The lambs overexpressing TLR4 had similar growth performance with non-transgenic lambs, and the blood physiological parameters of transgenic and non-transgenic were both in the normal range and did not show any difference.Conclusions： Here we establish an efficient platform for the production of transgenic sheep by the microinjection of pronuclear embryos during the whole year. The over-expression of TLR4 had no adverse effect on the growth of the sheep.展开更多
Heterogeneously integrated lasers in the O-band are a key component in realizring low-power optical interconnects for data centers and high-performance computing.Quantum-dot-based materials have been particularly appe...Heterogeneously integrated lasers in the O-band are a key component in realizring low-power optical interconnects for data centers and high-performance computing.Quantum-dot-based materials have been particularly appealing for light generation due to their ultralow lasing thresholds,small linewidth enhancement factor,and low sensitivity to reflections.Here,we present widely tunable quantum-dot lasers heterogencously integrated on silicon-on-insulator substrate.The tuning mechanism is based on Vernier dual-ring geometry,and a 47nm tuning range with 52 dB side-mode suppression ratio is observed.These parameters show an increase to 52nm and 58 dB,respectively,when an additional wavelength filter in the form of a Mach-Zehnder interferometer is added to the cavity.The Lorentzian linewidth of the lasers is measured as low as 5.3 kHz.展开更多
基金supported by grants from National Transgenic Creature Breeding Grand Project (2014ZX08008-005)
文摘Background： Brucella is a zoonotic Gram-negative pathogen that causes abortion and infertility in ruminants and humans. TLR4 is the receptor for LPS which can recognize Brucella and initiate antigen-presenting cell activities that affect both innate and adaptive immunity. Consequently, transgenic sheep over-expressing TLR4 are an suitable model to investigate the effects of TLR4 on preventing Brucellosis. In this study, we generated transgenic sheep overexpressing TLR4 and aimed to evaluate the effects of different seasons（breeding and non-breeding season） on superovulation and the imported exogenous gene on growth.Results： In total of 43 donor ewes and 166 recipient ewes in breeding season, 37 donor ewes and 144 recipient ewes in non-breeding season were selected for super-ovulation and injected embryo transfer to generate transgenic sheep.Our results indicated the no. of embryos recovered of donors and the rate of pronuclear embryos did not show any significant difference between breeding and non-breeding seasons（P 〉 0.05）. The positive rate of exogenous TLR4 tested were 21.21 % and 22.58 % in breeding and non-breeding season by Southern blot. The expression level of TLR4 in the transgenic sheep was 1.5 times higher than in the non-transgenic group（P 〈 0.05）. The lambs overexpressing TLR4 had similar growth performance with non-transgenic lambs, and the blood physiological parameters of transgenic and non-transgenic were both in the normal range and did not show any difference.Conclusions： Here we establish an efficient platform for the production of transgenic sheep by the microinjection of pronuclear embryos during the whole year. The over-expression of TLR4 had no adverse effect on the growth of the sheep.
基金Defense Advanced Research Projects Agency(HROO11-19-C-0083)Advanced Research Projects Agency-Energy(DE-AR0001039).
文摘Heterogeneously integrated lasers in the O-band are a key component in realizring low-power optical interconnects for data centers and high-performance computing.Quantum-dot-based materials have been particularly appealing for light generation due to their ultralow lasing thresholds,small linewidth enhancement factor,and low sensitivity to reflections.Here,we present widely tunable quantum-dot lasers heterogencously integrated on silicon-on-insulator substrate.The tuning mechanism is based on Vernier dual-ring geometry,and a 47nm tuning range with 52 dB side-mode suppression ratio is observed.These parameters show an increase to 52nm and 58 dB,respectively,when an additional wavelength filter in the form of a Mach-Zehnder interferometer is added to the cavity.The Lorentzian linewidth of the lasers is measured as low as 5.3 kHz.
