14 research outputs found
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Increasing ambient temperature progressively disassembles Arabidopsis phytochrome B from individual photobodies with distinct thermostabilities.
Warm temperature is postulated to induce plant thermomorphogenesis through a signaling mechanism similar to shade, as both destabilize the active form of the photoreceptor and thermosensor phytochrome B (phyB). At the cellular level, shade antagonizes phyB signaling by triggering phyB disassembly from photobodies. Here we report temperature-dependent photobody localization of fluorescent protein-tagged phyB (phyB-FP) in the epidermal cells of Arabidopsis hypocotyl and cotyledon. Our results demonstrate that warm temperature elicits different photobody dynamics than those by shade. Increases in temperature from 12 °C to 27 °C incrementally reduce photobody number by stimulating phyB-FP disassembly from selective thermo-unstable photobodies. The thermostability of photobodies relies on phyB's photosensory module. Surprisingly, elevated temperatures inflict opposite effects on phyB's functions in the hypocotyl and cotyledon despite inducing similar photobody dynamics, indicative of tissue/organ-specific temperature signaling circuitry either downstream of photobody dynamics or independent of phyB. Our results thus provide direct cell biology evidence supporting an early temperature signaling mechanism via dynamic assembly/disassembly of individual photobodies possessing distinct thermostabilities
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Publisher Correction: Increasing ambient temperature progressively disassembles Arabidopsis phytochrome B from individual photobodies with distinct thermostabilities.
An amendment to this paper has been published and can be accessed via a link at the top of the paper
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Distinguishing individual photobodies using Oligopaints reveals thermo-sensitive and -insensitive phytochrome B condensation at distinct subnuclear locations.
Photobodies (PBs) are membraneless subnuclear organelles that self-assemble via concentration-dependent liquid-liquid phase separation (LLPS) of the plant photoreceptor and thermosensor phytochrome B (PHYB). The current PHYB LLPS model posits that PHYB phase separates randomly in the nucleoplasm regardless of the cellular or nuclear context. Here, we established a robust Oligopaints method in Arabidopsis to determine the positioning of individual PBs. We show surprisingly that even in PHYB overexpression lines - where PHYB condensation would be more likely to occur randomly - PBs positioned at twelve distinct subnuclear locations distinguishable by chromocenter and nucleolus landmarks, suggesting that PHYB condensation occurs nonrandomly at preferred seeding sites. Intriguingly, warm temperatures reduce PB number by inducing the disappearance of specific thermo-sensitive PBs, demonstrating that individual PBs possess different thermosensitivities. These results reveal a nonrandom PB nucleation model, which provides the framework for the biogenesis of spatially distinct individual PBs with diverse environmental sensitivities within a single plant nucleus
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Increasing ambient temperature progressively disassembles Arabidopsis phytochrome B from individual photobodies with distinct thermostabilities.
Warm temperature is postulated to induce plant thermomorphogenesis through a signaling mechanism similar to shade, as both destabilize the active form of the photoreceptor and thermosensor phytochrome B (phyB). At the cellular level, shade antagonizes phyB signaling by triggering phyB disassembly from photobodies. Here we report temperature-dependent photobody localization of fluorescent protein-tagged phyB (phyB-FP) in the epidermal cells of Arabidopsis hypocotyl and cotyledon. Our results demonstrate that warm temperature elicits different photobody dynamics than those by shade. Increases in temperature from 12 °C to 27 °C incrementally reduce photobody number by stimulating phyB-FP disassembly from selective thermo-unstable photobodies. The thermostability of photobodies relies on phyB's photosensory module. Surprisingly, elevated temperatures inflict opposite effects on phyB's functions in the hypocotyl and cotyledon despite inducing similar photobody dynamics, indicative of tissue/organ-specific temperature signaling circuitry either downstream of photobody dynamics or independent of phyB. Our results thus provide direct cell biology evidence supporting an early temperature signaling mechanism via dynamic assembly/disassembly of individual photobodies possessing distinct thermostabilities
The Transcriptional Coregulator LEUNIG_HOMOLOG Inhibits Light-Dependent Seed Germination in Arabidopsis
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Photobody formation spatially segregates two opposing phytochrome B signaling actions of PIF5 degradation and stabilization.
Photoactivation of the plant photoreceptor and thermosensor phytochrome B (PHYB) triggers its condensation into subnuclear membraneless organelles named photobodies (PBs). However, the function of PBs in PHYB signaling remains frustratingly elusive. Here, we found that PHYB recruits PHYTOCHROME-INTERACTING FACTOR 5 (PIF5) to PBs. Surprisingly, PHYB exerts opposing roles in degrading and stabilizing PIF5. Perturbing PB size by overproducing PHYB provoked a biphasic PIF5 response: while a moderate increase in PHYB enhanced PIF5 degradation, further elevating the PHYB level stabilized PIF5 by retaining more of it in enlarged PBs. Conversely, reducing PB size by dim light, which enhanced PB dynamics and nucleoplasmic PHYB and PIF5, switched the balance towards PIF5 degradation. Together, these results reveal that PB formation spatially segregates two antagonistic PHYB signaling actions - PIF5 stabilization in PBs and PIF5 degradation in the surrounding nucleoplasm - which could enable an environmentally sensitive, counterbalancing mechanism to titrate nucleoplasmic PIF5 and environmental responses
Acridine Based Small Molecular Hole Transport Type Materials for Phosphorescent OLED Application
Two small molecular hole-transporting type materials, namely 4-(9,9-dimethylacridin-10(9H)-yl)-N-(4-(9,9-dimethylacridin-10(9H)-yl)phenyl)-N-phenylaniline (TPA-2ACR) and 10,10′-(9-phenyl-9H-carbazole-3,6-diyl)bis(9,9-dimethyl-9,10-dihydroacridine) (PhCAR-2ACR), were designed and synthesized using a single-step Buchwald–Hartwig amination between the dimethyl acridine and triphenylamine or carbazole moieties. Both materials showed high thermal decomposition temperatures of 402 and 422 °C at 5% weight reduction for PhCAR-2ACR and TPA-2ACR, respectively. TPA-2ACR as hole-transporting material exhibited excellent current, power, and external quantum efficiencies of 55.74 cd/A, 29.28 lm/W and 21.59%, respectively. The achieved device efficiencies are much better than that of the referenced similar, 1,1-Bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC)-based device (32.53 cd/A, 18.58 lm/W and 10.6%). Moreover, phenyl carbazole-based PhCAR-2ACR showed good device characteristics when applied for host material in phosphorescent OLEDs
Detection and hazard assessment of pathogenic microorganisms in medical wastes
This study was undertaken to investigate the types and concentrations of microbial agents in various medical wastes as well as to characterize their survivals in these wastes at different temperatures for microbial risk assessment. Medical wastes collected from 5 major hospitals in South Korea were classified and stored at three different temperatures (-20, 6, and 30 degrees C). Presence of various microorganisms such as pathogenic viruses and bacteria were investigated by both cultivation and by (RT)-PCR assays. A number of (opportunistic) pathogenic bacteria, including Pseudomonas spp., Lactobacillus spp., Staphylococcus spp., Micrococcus spp., Kocuria spp., Brevibacillus spp., Microbacterium oxydans, and Propionibacterium acnes, were identified from the various medical wastes. In addition, pathogenic viruses such as noroviruses and hepatitis B virus were also detected in one of the human tissue wastes. Commonly identified bacterial and viral pathogens such as Pseudomonas spp., Corynebacterium diphtheriae, Escherichia coli, Staphylococcus spp., and respiratory synctial virus (RSV) were inoculated into either gauzes or diapers, and their survivals were characterized. Viral agents such as RSV showed poor survival in most environmental conditions, and demonstrated that various pathogens could be present in medical wastes but that the associated health risk appeared to be low. However, medical waste should be carefully controlled and monitored to prevent nosocomial infection associated with the exposure to these wastes.Lee J, 2008, APPL ENVIRON MICROB, V74, P2111, DOI 10.1128/AEM.02442-07Marinkovic N, 2008, WASTE MANAGE, V28, P1049, DOI 10.1016/j.wasman.2007.01.021Shariati B, 2007, J OCCUP HEALTH, V49, P317de Bruin E, 2006, J VIROL METHODS, V137, P259, DOI 10.1016/j.jviromet.2006.06.024Garcia C, 2006, J CLIN MICROBIOL, V44, P2997, DOI 10.1128/JCM.00065-06Jang YC, 2006, J ENVIRON MANAGE, V80, P107, DOI 10.1016/j.jenvman.2005.08.018ZIEBUHR W, 2006, INT J ANTIMICROB AG, V28, P14Phipps LP, 2004, J VIROL METHODS, V122, P119, DOI 10.1016/j/jviromet.2004.08.008Loberto JCS, 2004, BRAZ J MICROBIOL, V35, P64Seo SH, 2002, NAT MED, V8, P950, DOI 10.1038/nm757Nema SK, 2002, CURR SCI INDIA, V83, P271Katayama K, 2002, VIROLOGY, V299, P225, DOI 10.1006/viro.2002.1568Katayama H, 2002, APPL ENVIRON MICROB, V68, P1033, DOI 10.1128/AEM.68.3.1033-1039.2002Monpoeho S, 2001, APPL ENVIRON MICROB, V67, P2484SALKIN IF, 2001, REV HLTH IMPACTS MICManfredi R, 2000, EUR J EPIDEMIOL, V16, P111Kuo HW, 1999, WATER AIR SOIL POLL, V114, P413Kim BJ, 1999, J CLIN MICROBIOL, V37, P1714HAAS C, 1999, QUANTITATIVE MICROBIKane A, 1999, B WORLD HEALTH ORGAN, V77, P801PRUSS A, 1999, SAFE MANAGEMENT WAST, P20Schlegel L, 1998, EUR J CLIN MICROBIOL, V17, P887Frank U, 1997, CLIN INFECT DIS, V25, P318BELL DM, 1997, AM J MED S5B, V102, P9Lee CC, 1996, J HAZARD MATER, V48, P1GOLDENBERGER D, 1995, PCR METH APPL, V4, P368OHMAN SC, 1995, ACTA ODONTOL SCAND, V53, P49PATEL R, 1994, CLIN INFECT DIS, V18, P207PATTI JM, 1994, INFECT IMMUN, V62, P152TANAKA MM, 1994RUTALA WA, 1992, INFECT CONT HOSP EP, V13, P3848EDWARDS U, 1989, NUCLEIC ACIDS RES, V17, P7843
Noise Localization Method for Model Tests in a Large Cavitation Tunnel Using a Hydrophone Array
Model tests are performed in order to predict the noise level of a full ship and to control its noise signature. Localizing noise sources in the model test is therefore an important research subject along with measuring noise levels. In this paper, a noise localization method using a hydrophone array in a large cavitation tunnel is presented. The 45-channel hydrophone array was designed using a global optimization technique for noise measurement. A set of noise experiments was performed in the KRISO (Korea Research Institute of Ships & Ocean Engineering) large cavitation tunnel using scaled models, including a ship with a single propeller, a ship with twin propellers and an underwater vehicle. The incoherent broadband processors defined based on the Bartlett and the minimum variance (MV) processors were applied to the measured data. The results of data analysis and localization are presented in the paper. Finally, it is shown that the mechanical noise, as well as the propeller noise can be successfully localized using the proposed localization method