33 research outputs found
c-Met activation leads to the establishment of a TGFβ-receptor regulatory network in bladder cancer progression
No full text10.1038/s41467-019-12241-2Nature Communications10
Genetic Basis for the Hierarchical Interaction Between <i>Tobamovirus</i> spp. and <i>L</i> Resistance Gene Alleles from Different Pepper Species
No full text The pepper L gene conditions the plant's resistance to Tobamovirus spp. Alleles L1, L2, L3, and L4 confer a broadening spectra of resistance to different virus pathotypes. In this study, we report the genetic basis for the hierarchical interaction between L genes and Tobamovirus pathotypes. We cloned L3 using map-based methods, and L1, L1a, L1c, L2, L2b, and L4 using a homology-based method. L gene alleles encode coiled-coil, nucleotide-binding, leucine-rich repeat (LRR)-type resistance proteins with the ability to induce resistance response to the viral coat protein (CP) avirulence effectors by themselves. Their different recognition spectra in original pepper species were reproduced in an Agrobacterium tumefaciens–mediated transient expression system in Nicotiana benthamiana. Chimera analysis with L1, which showed the narrowest recognition spectrum, indicates that the broader recognition spectra conferred by L2, L2b, L3, and L4 require different subregions of the LRR domain. We identified a critical amino acid residue for the determination of recognition spectra but other regions also influenced the L genes' resistance spectra. The results suggest that the hierarchical interactions between L genes and Tobamovirus spp. are determined by the interaction of multiple subregions of the LRR domain of L proteins with different viral CP themselves or some protein complexes including them. </jats:p
Formation of I2+III2 supercomplex rescues respiratory chain defects
No full text: Mitochondrial electron transport chain (ETC) complexes partition between free complexes and quaternary assemblies known as supercomplexes (SCs). However, the physiological requirement for SCs and the mechanisms regulating their formation remain controversial. Here, we show that genetic perturbations in mammalian ETC complex III (CIII) biogenesis stimulate the formation of a specialized extra-large SC (SC-XL) with a structure of I2+III2, resolved at 3.7 Å by cryoelectron microscopy (cryo-EM). SC-XL formation increases mitochondrial cristae density, reduces CIII reactive oxygen species (ROS), and sustains normal respiration despite a 70% reduction in CIII activity, effectively rescuing CIII deficiency. Consequently, inhibiting SC-XL formation in CIII mutants using the Uqcrc1DEL:E258-D260 contact site mutation leads to respiratory decompensation. Lastly, SC-XL formation promotes fatty acid oxidation (FAO) and protects against ischemic heart failure in mice. Our study uncovers an unexpected plasticity in the mammalian ETC, where structural adaptations mitigate intrinsic perturbations, and suggests that manipulating SC-XL formation is a potential therapeutic strategy for mitochondrial dysfunction
Author Correction: c-Met activation leads to the establishment of a TGFβ-receptor regulatory network in bladder cancer progression (Nature Communications, (2019), 10, 1, (4349), 10.1038/s41467-019-12241-2)
No full text© 2019, The Author(s). The original version of this Article contained an error in the spelling of the author Azad Saei, which was incorrectly given as Azad Saie. This has now been corrected in both the PDF and HTML versions of the Article
Lasing in Bose-Fermi mixtures
No full textA.K. acknowledges the support from the EPSRC Established Career Fellowship. V.K., M.D., V.F.S. and A.K. acknowledge support from the Russian Ministry of Science and Education, contract (contract No. 11.G34.31.0067). P.G.S. acknowledges support from Greek GSRT program Aristeia (grant No. 1978). C.S., M. A. J.F., M.K and S.H. acknowledge support from the state of Bavaria.Light amplification by stimulated emission of radiation, well-known for revolutionising photonic science, has been realised primarily in fermionic systems including widely applied diode lasers. The prerequisite for fermionic lasing is the inversion of electronic population, which governs the lasing threshold. More recently, bosonic lasers have also been developed based on Bose-Einstein condensates of exciton-polaritons in semiconductor microcavities. These electrically neutral bosons coexist with charged electrons and holes. In the presence of magnetic fields, the charged particles are bound to their cyclotron orbits, while the neutral exciton-polaritons move freely. We demonstrate how magnetic fields affect dramatically the phase diagram of mixed Bose-Fermi systems, switching between fermionic lasing, incoherent emission and bosonic lasing regimes in planar and pillar microcavities with optical and electrical pumping. We collected and analyzed the data taken on pillar and planar microcavity structures at continuous wave and pulsed optical excitation as well as injecting electrons and holes electronically. Our results evidence the transition from a Bose gas to a Fermi liquid mediated by magnetic fields and light-matter coupling.Peer reviewe
Density clamping and longitudinal spatial hole burning in a gain-clamped semiconductor optical amplifier
No full textWe have directly measured, under operating conditions, the distributions of carrier densities and temperatures in a gain-clamped semiconductor optical amplifier designed for operation at 1.55 mum. As expected, longitudinal spatial hole burning is much smaller than in conventional semiconductor optical amplifiers and the effects of gain clamping are clearly evidenced. The amplifier nevertheless shows a sizeable temperature increase for both the lattice and the carriers at high currents, which are attributed to contributions of Auger recombination, intervalence band absorption, and Joule and recombination heating. (C) 2002 American Institute of Physics.LOEQSwiss Fed Inst Technol, EPFL, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland. Alcatel Res & Innovat, F-91461 Marcoussis, France. Univ Tokyo, Inst Ind Sci, Meguro Ku, Tokyo 1538505, Japan. Nomura, MS, Swiss Fed Inst Technol, EPFL, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland.ISI Document Delivery No.: 599DGCited Reference Count: 19Cited References:AGRAWAL GP, 1986, LONG WAVELENGTH SEMIBACHMANN M, 1996, ELECTRON LETT, V32, P2076BAUER B, 1994, IEEE PHOTONIC TECH L, V6, P182BENNETT AJ, 1998, J APPL PHYS, V83, P3784EVANS PA, 1994, SEMICOND SCI TECH, V9, P1740FANG WCW, 1995, IEEE J SEL TOP QUANT, V1, P117FEHR JN, 2001, APPL PHYS LETT, V78, P4079FEHR JN, 2002, IEEE J QUANTUM ELECT, V38, P674GIRARDIN F, 1997, IEEE J SEL TOP QUANT, V3, P461HESSLER T, 1997, QUANTUM SEMICL OPT, V9, P675JOYCE WB, 1977, APPL PHYS LETT, V31, P354KAPPEI L, UNPUBPLEUMEEKERS JL, 1998, IEEE J QUANTUM ELECT, V34, P879REES P, 1995, IEEE J QUANTUM ELECT, V31, P1047RINNER F, 2002, APPL PHYS LETT, V80, P19SALLERAS F, UNPUBSCHAAFSMA DT, 1999, IEEE PHOTONIC TECH L, V11, P727SIMON JC, 1994, ELECTRON LETT, V30, P49WOLFSON D, 1999, IEEE PHOTONIC TECH L, V11, P149
A Tradeoff Between the Escape from <i>N</i>′-Mediated Resistance and Virulence in Pepper Mild Mottle Virus Through Reduced Virus Accumulation
No full textN′ resistance is intrinsically broken by tobacco mosaic virus but is still effective against pepper mild mottle virus (PMMoV), including those breaking L resistance in peppers. To evaluate the durability of N′ resistance to PMMoV, we performed random mutagenesis of the coat protein (CP) gene of PMMoV. We isolated 11 CP mutants with two to six amino acid changes that escaped the N′-mediated resistance response in Nicotiana sylvestris. Some mutants and their derivatives, which had minimal mutations to escape N′-mediated resistance, exhibited reduced accumulation in inoculated leaves and loss of systemic infectivity in a susceptible pepper (Capsicum annuum) cultivar, as determined by RT-PCR analysis. Although the mutant CPs also escaped recognition by L3 and L4 resistance proteins from pepper in transient expression assays, the loss of systemic infectivity suggests that the mutants are unlikely to overcome L-mediated resistance. In Nicotiana benthamiana, a highly susceptible systemic host of PMMoV, ELISA and RT-qPCR indicated that the mutants consistently infected the host systemically, albeit with attenuated virulence and reduced virus accumulation, especially in younger leaves. The results collectively suggest that the reduced virus accumulation enabled the mutant PMMoV to escape N′-mediated resistance, and as a trade-off, compromised its virulence. The results also suggest that PMMoV CP modulates the systemic symptoms
Direct observation of longitudinal spatial hole burning in semiconductor optical amplifiers with injection
No full textMeasurements of spontaneous emission from InGaAsP semiconductor optical amplifiers provide information on both the carrier density and temperature. By spatially resolving the light emitted along the active layer of the device, we find evidence of longitudinal spatial hole burning which results from amplified spontaneous emission in the structure and is modified by the injected optical signal. Under injection, we also observe pronounced asymmetry of the amplified spontaneous emission intensity from the two facets which we relate to the carrier density profile. The experimental results are in good agreement with numerical simulations. An analysis of the measured spectra reveals an unexpected very high temperature (400 K) and its decrease by at least 35 K in the middle of the device when light is injected. (C) 2001 American Institute of Physics.LOEQSwiss Fed Inst Technol, IMO, Dept Phys, EPFL, CH-1015 Lausanne, Switzerland. Lucent Technol, Bell Labs, Holmdel, NJ 07739 USA. Alcatel Corp, Res Ctr, OPTO, Groupement Interet Econ, F-91461 Marcoussis, France. Fehr, JN, Swiss Fed Inst Technol, IMO, Dept Phys, EPFL, CH-1015 Lausanne, Switzerland.ISI Document Delivery No.: 443KHCited Reference Count: 11Cited References:EMERY JY, 1997, ELECTRON LETT, V33, P1083FANG WCW, 1995, IEEE J SEL TOP QUANT, V1, P117FEHR JN, UNPUB FURTHER EXPT PFEHR JN, 2000, C LAS EL OPT OSA OPT, P421GIRARDIN F, 1997, IEEE J SEL TOP QUANT, V3, P461GIRARDIN F, 1998, IEEE PHOTONIC TECH L, V10, P784HENRY CH, 1980, J APPL PHYS, V51, P3042KETELSEN LJP, 1991, IEEE J QUANTUM ELECT, V27, P957PLEUMEEKERS JL, 1997, THESIS U DELFT DELFTPLEUMEEKERS JL, 1998, IEEE J QUANTUM ELECT, V34, P879VALIENTE I, 1996, OSA TRENDS OPT PHOTO, V5, P18
Determination of the exciton formation in quantum wells from time-resolved interband luminescence
No full textWe present the results of a detailed time-resolved luminescence study carried out on a very high quality InGaAs quantum well sample where the contributions at the energy of the exciton and at the band edge can be clearly separated. We perform this experiment with a spectral resolution and a sensitivity of the setup, allowing us to keep the observation of these two separate contributions over a broad range of times and densities. This allows us to directly evidence the exciton formation time, which depends on the density as expected from theory. We also denote the dominant contribution of excitons to the luminescence signal, and the lack of thermodynamical equilibrium at low densities.LOEQEcole Polytech Fed Lausanne, Inst Photon & Elect Quant, CH-1015 Lausanne, Switzerland. Szczytko, J, Ecole Polytech Fed Lausanne, Inst Photon & Elect Quant, CH-1015 Lausanne, Switzerland., ISI Document Delivery No.: 857PS, Times Cited: 5, Cited Reference Count: 27, Cited References: , AGRANOVICH VM, 1966, JETP LETT, V3, P223, CHATTERJEE S, 2004, PHYS REV LETT, V92, DAMEN TC, 1990, PHYS REV B, V42, P7434, DEVEAUD B, 1987, APPL PHYS LETT, V51, P828, DEVEAUD B, 1991, PHYS REV LETT, V67, P2355, DEVEAUD B, 1993, J PHYS IV, V3, P11, HANNEWALD K, 2000, PHYS REV B, V62, P4519, HAYES GR, 2002, PHYS STATUS SOLIDI A, V190, P637, HOYER W, 2003, PHYS REV B, V67, KAINDL RA, 2003, NATURE, V423, P734, KIRA M, 1998, PHYS REV LETT, V81, P3263, KIRA M, 1999, PHYS REV LETT, V82, P3544, LASHER G, 1964, PHYS REV, V133, A553, LEO K, 1988, PHYS REV B, V38, P1947, MATSUSUE T, 1987, APPL PHYS LETT, V50, P1429, MILLER DAB, 1982, APPL PHYS LETT, V41, P679, PHILLIPS RT, 1996, SOLID STATE COMMUN, V98, P287, PIERMAROCCHI C, 1996, PHYS REV B, V53, P15834, PIERMAROCCHI C, 1997, PHYS REV B, V55, P1333, RIDLEY BK, 1990, PHYS REV B, V41, P12190, ROBART D, 1995, SOLID STATE COMMUN, V95, P287, RUHLE WW, 1989, PHYS REV B, V40, P1756, SHAH J, 1996, SOLID STATE SCI, V115, P161, SZCZYTKO J, 2004, PHYS STATUS SOLIDI C, V1, P493, THILAGAM A, 1993, J LUMIN, V55, P11, WEISBUCH C, 1981, SOLID STATE COMMUN, V37, P219, YOON HW, 1996, PHYS REV B, V54, P2763, 13740
