Diversity, function and regulation of cell surface and intracellular immune receptors in Solanaceae

The first layer of the plant immune system comprises plasma membrane-localized receptor proteins and intracellular receptors of the nucleotide-binding leucine-rich repeat protein superfamily. Together, these immune receptors act as a network of surveillance machines in recognizing extracellular and intracellular pathogen invasion-derived molecules, ranging from conserved structural epitopes to virulence-promoting effectors. Successful pathogen recognition leads to physiological and molecular changes in the host plants, which are critical for counteracting and defending against biotic attack. A breadth of significant insights and conceptual advances have been derived from decades of research in various model plant species regarding the structural complexity, functional diversity and regulatory mechanisms of these plant immune receptors. In this article, we review the current state-of-the-art of how these host surveillance proteins function and how they are regulated. We will focus on the latest progress made in plant species belonging to the Solanaceae family, because of their tremendous importance as model organisms and agriculturally valuable crops

Protective Effects of Corni Fructus against Advanced Glycation Endproducts and Radical Scavenging

We investigated the inhibition of advanced glycation endproduct (AGE) activity using the fluorescence characteristics of fractions and compounds from Corni Fructus. Corni Fructus extract and its iridoid glycoside components showed low inhibitory activities as well as the AGE inhibitor aminoguanidine. However, a low molecular weight polyphenol, 7-O-galloyl-D-sedoheptulose, and an antioxidant, trolox, showed high inhibitory activities compared with aminoguanidine under reactive conditions. The AGE-inhibiting activity of polyphenolic fractions of Corni Fructus ranged from a level comparable to Corni Fructus extract to the higher level of 7-O-galloyl-D-sedoheptulose. As well as the results of AGE-inhibiting activity, Corni Fructus extract and iridoid components showed low or no 1,1-diphenyl-2-pycrylhydrazyl (DPPH) radical-scavenging activities, whereas 7-O-galloyl-D-sedoheptulose showed a level comparable to trolox. Polyphenolic fractions of Corni Fructus quenched DPPH radicals in a concentration-dependent manner. Some fractions exerted a higher DPPH radical-scavenging activity compared with trolox and 7-O-galloyl-D-sedoheptulose. The DPPH radical-scavenging activity was significantly correlated with the AGE-inhibiting activity. These results suggest that polyphenolic fractions of Corni Fructus inhibited AGE formation by antioxidant activity including free radical scavenging. The strong DPPH radical-scavenging and AGE-inhibiting fractions included ellagitannins and polymeric proanthocyanidins

Feasibility of Micro Electrode Array (MEA) Based on Silicone-Polyimide Hybrid for Retina Prosthesis

Purpose: To adopt micropatterning technology in manufacturing silicone elastomer based microelectrode arrays for retinal stimulation, a silicone-polyimide hybrid microelectrode array was proposed and tested in vivo. Methods: Gold microelectrodes were created by semiconductor manufacturing technology based on polyimide, and were hybridized with silicone elastomer by spin coating. The stability of the hybrid between the two materials was flex and blister tested. The feasibility of the hybrid electrode was evaluated in rabbit eye by reviewing optical coherence tomography (OCT) findings after suprachoroidal implantation. Results: The flex test showed no dehiscence between the two materials for 24 h of alternative flexion and extension from -45.0° to +45.0°. During the blister test, delamination was observed at 8.33±1.36 psi of pressure stress; however, this property was improved to 11.50±1.04 psi by oxygen plasma treatment before hybridization. OCT examination revealed that, the implanted electrodes were safely located in the suprachoroidal space during the 4-week follow-up period. Conclusion: The silicone-polyimide hybrid microelectrode array showed moderate physical properties, which are suitable for in vivo application. Appropriate pretreatment before hybridization improved electrode stability. In vivo testing indicated that thiselectrode is suitable as a stimulation electrode in artificial retina.This paper was supported by the Korea Science and Engineering Foundation (KOSEF) through the Nano Bioelectronics and Systems Research Center (NBS-ERC) at Seoul National University, and by a grant from the Korea Health 21 R&D Project(A050251), Ministry of Health & Welfare, Republic of Korea

Development of Microelectrode Arrays for Artificial Retinal Implants using Liquid Crystal Polymers

Purpose: To develop a liquid crystal polymer (LCP) based, long-term implantable, retinal stimulation microelectrode array using a novel fabrication method. Methods: The fabrication process used laser micromachining and customized thermal press bonding to produce LCP based microelectrode arrays. To evaluate the fabrication process and the resulting electrode arrays, in vitro reliability tests and in vivo animal experiments were performed. The in vitro tests consisted of electrode site impedance recording and electrode inter-layer adhesion monitoring during accelerated soak tests. For in vivo testing, the fabricated electrode arrays were implanted in the suprachoroidal space of rabbit eyes. Optical coherence tomography (OCT) and electrically evoked cortical potentials (EECPs) were used to determine long-term biocompatibility and functionality of the implant.Results: The fabricated structure had a smooth, rounded edge profile and exhibited moderate flexibility, which are advantageous features for safe implantation without guide tools. Following accelerated soak tests at 75°C in phosphate buffered saline, the electrode sites showed no degradation and the inter-layer adhesion of the structure showed acceptable stability for more than 2 months. The electrode arrays were safely implanted in the suprachoroidal space of rabbit eyes, and 1 EECP waveforms were recorded. Over a 3-month postoperative period, no choroioretinal inflammation or structural deformities were observed by OCT and histological examination. Conclusions: LCP based flexible microelectrode arrays can be successfully applied as retinal prostheses. The results demonstrate that such electrode arrays are safe, biocompatible, mechanically stable, and can be effective as part of a chronic retinal implant system.This paper was supported by the Korea Science and Engineering Foundation (KOSEF) through the Nano Bioelectronics and Systems Research Center (NBS-ERC) at Seoul National University, and by a grant from the Korea Health 21 R&D Project(A050251), Ministry of Health & Welfare, Republic of Korea

Hereditary and Clinical Features of Retinitis Pigmentosa in Koreans

There has been no report about hereditary and clinical features of retinitis pigmentosa (RP) in Koreans. To evaluate these, data were collected from 365 RP patients including age, gender, visual acuity (VA), spherical equivalent (SE) of refractive errors, funduscopic findings, color vision test, visual field score (VFS) obtained from Goldmann perimetry, and the inheritance patterns from pedigrees. Simplex RP was the most common inheritance pattern (61.9%); followed by autosomal recessive RP (17.3%), autosomal dominant RP (12.1%) and X-linked recessive RP (8.8%). Myopia was the most common refractive errors (77.5%) including 16.1% of high myopia. The most common cataract type was posterior subcapsular cataract (25.8%). Observed retinal findings included changes of retinal pigment epithelium (88.8%), bony spicule-like pigmentation (79.7%), attenuation of retinal vessel (76.2%), waxy disc pallor (12.6%), golden ring around optic disc (2.2%), epiretinal membrane (0.8%) and cystoid macular edema (0.5%). Corrected VA and refractive errors did not show any significant difference between the inheritance patterns. VFS was significantly worse in autosomal recessive RP than in autosomal dominant RP. Color vision defect was noted in 66.1% on Hardy-Rand-Rittlers color vision test. In conclusion, Korean RP patients have the indigenous hereditary and clinical features as well as the ordinary ones

Increasing the resilience of plant immunity to a warming climate

Extreme weather conditions associated with climate change affect many aspects of plant and animal life, including the response to infectious diseases. Production of salicylic acid (SA), a central plant defence hormone, is particularly vulnerable to suppression by short periods of hot weather above the normal plant growth temperature range via an unknown mechanism. Here we show that suppression of SA production in Arabidopsis thaliana at 28 °C is independent of PHYTOCHROME B (phyB) and EARLY FLOWERING 3 (ELF3), which regulate thermo-responsive plant growth and development. Instead, we found that formation of GUANYLATE BINDING PROTEIN-LIKE 3 (GBPL3) defence-activated biomolecular condensates (GDACs) was reduced at the higher growth temperature. The altered GDAC formation in vivo is linked to impaired recruitment of GBPL3 and SA-associated Mediator subunits to the promoters of CBP60g and SARD1, which encode master immune transcription factors. Unlike many other SA signalling components, including the SA receptor and biosynthetic genes, optimized CBP60g expression was sufficient to broadly restore SA production, basal immunity and effector-triggered immunity at the elevated growth temperature without significant growth trade-offs. CBP60g family transcription factors are widely conserved in plants. These results have implications for safeguarding the plant immune system as well as understanding the concept of the plant–pathogen–environment disease triangle and the emergence of new disease epidemics in a warming climate