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"Kim, Ki-Tae"
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Two nuclear effectors of the rice blast fungus modulate host immunity via transcriptional reprogramming
2020
Pathogens utilize multiple types of effectors to modulate plant immunity. Although many apoplastic and cytoplasmic effectors have been reported, nuclear effectors have not been well characterized in fungal pathogens. Here, we characterize two nuclear effectors of the rice blast pathogen
Magnaporthe oryzae
. Both nuclear effectors are secreted via the biotrophic interfacial complex, translocated into the nuclei of initially penetrated and surrounding cells, and reprogram the expression of immunity-associated genes by binding on effector binding elements in rice. Their expression in transgenic rice causes ambivalent immunity: increased susceptibility to
M
.
oryzae
and
Xanthomonas oryzae
pv.
oryzae
, hemibiotrophic pathogens, but enhanced resistance to
Cochliobolus miyabeanus
, a necrotrophic pathogen. Our findings help remedy a significant knowledge deficiency in the mechanism of
M
.
oryzae
–rice interactions and underscore how effector-mediated manipulation of plant immunity by one pathogen may also affect the disease severity by other pathogens.
Plant pathogens secrete various effectors to manipulate host immunity. Here, Kim et al. describe two
Magnaporthe oryzae
effectors that translocate into the nuclei of infected rice cells and reprogram expression of immunity-associated genes, increasing susceptibility to hemibiotrophic pathogens.
Journal Article
New reference genome sequences of hot pepper reveal the massive evolution of plant disease-resistance genes by retroduplication
by
Kim, Saet-Byul
,
Kang, Byoung-Cheorl
,
Park, Minkyu
in
Angiosperms
,
Animal Genetics and Genomics
,
Annotations
2017
Background
Transposable elements are major evolutionary forces which can cause new genome structure and species diversification. The role of transposable elements in the expansion of nucleotide-binding and leucine-rich-repeat proteins (NLRs), the major disease-resistance gene families, has been unexplored in plants.
Results
We report two high-quality de novo genomes (
Capsicum baccatum
and
C. chinense
) and an improved reference genome (
C. annuum
) for peppers. Dynamic genome rearrangements involving translocations among chromosomes 3, 5, and 9 were detected in comparison between
C. baccatum
and the two other peppers. The amplification of
athila
LTR-retrotransposons, members of the
gypsy
superfamily, led to genome expansion in
C. baccatum
. In-depth genome-wide comparison of genes and repeats unveiled that the copy numbers of NLRs were greatly increased by LTR-retrotransposon-mediated retroduplication. Moreover, retroduplicated NLRs are abundant across the angiosperms and, in most cases, are lineage-specific.
Conclusions
Our study reveals that retroduplication has played key roles for the massive emergence of NLR genes including functional disease-resistance genes in pepper plants.
Journal Article
Improvement of Wireless Localization Precision Using Chirp Signals
2025
This study presents a novel localization framework that leverages the unique properties of chirp signals combined with a time division multiple access (TDMA)-based tactical data link to achieve high-precision positioning. Chirp signals, with their wide bandwidth and high temporal resolution, enable an oversampling-like effect, significantly enhancing distance estimation accuracy without the need for additional sampling rates. The proposed framework integrates chirp-based ranging and localization algorithms, incorporating raised cosine interpolation and circular shift techniques to improve temporal resolution and ensure precise peak detection. By utilizing the time differential of arrival (TDoA) and Fang’s algorithm, the system demonstrates robust performance, effectively mitigating challenges posed by multipath interference and jamming. The TDMA system provides synchronized time slots, allowing the seamless integration of communication and localization functionalities while ensuring stable and efficient operation. Experimental evaluations under various environmental conditions, including dense multipath and high-jamming scenarios, confirm the framework’s superiority over conventional localization methods in terms of accuracy, reliability, and resilience. These results highlight the framework’s potential applications in diverse fields, such as Internet of Things (IoT) networks, smart city infrastructure, and tactical communication systems, where high precision and robust localization are critical.
Journal Article
An Acridine-Based Fluorescent Sensor for Monitoring ClO− in Water Samples and Zebrafish
2020
A novel acridine-based fluorescent chemosensor, BK ((E)-2-((acridine-9-ylimino)methyl)-N-benzhydrylhydrazine-1-carbothioamide), for monitoring ClO− was prepared. The sensor BK was synthesized by introducing a new synthetic route of making aldehyde group using formic hydrazide. Probe BK displayed notable fluorescence quenching in the presence of ClO− and showed a great selectivity over other guest analytes. The detection limit was calculated to be 7.65 μM. Additionally, BK was satisfactorily applied for sensing ClO− in water samples and zebrafish.
Journal Article
Sorbus commixta Fruit Extract Suppresses Lipopolysaccharide-Induced Neuroinflammation in BV-2 Microglia Cells via the MAPK and NF-κB Signaling Pathways
by
Jung, Jin-Hwa
,
Kim, Ki-Tae
,
Kim, Yon-Suk
in
Acids
,
Animals
,
Anti-Inflammatory Agents - chemistry
2024
Sorbus commixta Hedl. is a traditional medicinal plant in Korea, China, and Japan with known antioxidative, anti-inflammatory, anti-atherogenic, and anti-melanin activities. However, its anti-neuroinflammatory effects remain largely unknown. In this study, we investigated the inhibitory effects of S. commixta fruit extracts on lipopolysaccharide-stimulated pro-inflammatory factors in BV-2 microglia. We compared the anti-neuroinflammatory activity of S. commixta fruit water extract (SFW) and 70% ethanol extract using a nitric oxide assay. Our data indicated that the SFW (25–100 μg/mL) treatment significantly inhibited excessive nitric oxide production in lipopolysaccharide-stimulated BV-2 microglia compared to the 70% ethanol extract. It also attenuated the expression of inducible nitric oxide synthase, cyclooxygenase-2, and pro-inflammatory cytokines such as interleukin-6 and tumor necrosis factor α. Moreover, SFW exhibited its anti-inflammatory properties by downregulating the expression of factors involved in the extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinase pathways and by suppressing nuclear factor kappa B. Caffeic acid was identified as a primary component of SFW showing anti-neuroinflammatory activity. These findings suggest that SFW may offer substantial therapeutic potential for the treatment of neurodegenerative diseases involving microglia activation.
Journal Article
Genome diversity, population structure and MALDI-TOF MS profiling of Aspergillus oryzae/flavus strains from fermentation and wild environments
by
Hong, Seung-Beom
,
Kim, Dong-Chan
,
Kim, Ki-Tae
in
Aflatoxin
,
Aflatoxins
,
Aflatoxins - genetics
2025
Various strains of
Aspergillus oryzae
, regarded as a domesticated variant of aflatoxigenic
Aspergillus flavus
, are utilized in the soybean fermentation industry of Korea. This study compared
A. oryzae/flavus
strains isolated from various environments in Korea including industrial settings, Meju (brick of dried fermented soybeans), and wild conditions with globally reported strains using genomic analysis to determine their taxonomic positions and risk of mycotoxicity. Using population genomics, five distinct groups (A to E) were identified, with all aflatoxigenic Korean strains in Group C and non-aflatoxigenic Korean strains in Groups A, B, and E. Korean strains from Meju and wild conditions are distributed across Groups A and B, and most of the Korean industrial strains form a sub-cluster with Japanese industrial strains in Group A. Comparing secondary metabolite gene cluster mutation pattern, three gene clusters (Aflatoxin, Cyclopiazonic acid and Ditryptophenaline) were revealed as group specific ones. In aflatoxin and cyclopiazonic acid clusters, most of the Group C strains had intact regions compared to strains in other groups. Since most of the Group C strains produce aflatoxin and have intact Aflatoxin and Cyclopiazonic acid gene clusters, we considered that this group represent
A. flavus
. Profiling using MALDI-TOF MS analysis also distinguished Group C from Groups A, B and E by specific three proteomic peaks. Among the three peaks, those around 12,700 to 12,900 m/z (Da) are expected to correspond to AflF (nor B), an enzyme involved in Aflatoxin metabolism. These results showed taxonomic positions of Korean strains of
A. oryzae/flavus
from various environments and also showed possibility to differentiate between
A. oryzae
and
A. flavus
with genome and MALDI-TOF MS analysis.
Journal Article
Nicotinamide enhances osteoblast differentiation through activation of the mitochondrial antioxidant defense system
2023
Although the normal physiological level of oxidative stress is beneficial for maintaining bone homeostasis, imbalance between reactive oxygen species (ROS) production and antioxidant defense can cause various bone diseases. The purpose of this study was to determine whether nicotinamide (NAM), an NAD
+
precursor, can support the maintenance of bone homeostasis by regulating osteoblasts. Here, we found that NAM enhances osteoblast differentiation and mitochondrial metabolism. NAM increases the expression of antioxidant enzymes, which is due to increased FOXO3A transcriptional activity via SIRT3 activation. NAM has not only a preventive effect against weak and chronic oxidative stress but also a therapeutic effect against strong and acute exposure to H
2
O
2
in osteoblast differentiation. Collectively, the results indicate that NAM increases mitochondrial biogenesis and antioxidant enzyme expression through activation of the SIRT3-FOXO3A axis, which consequently enhances osteoblast differentiation. These results suggest that NAM could be a potential preventive or therapeutic agent for bone diseases caused by ROS.
Bone health: Vitamin B3 boosts anti-oxidants
A form of vitamin B3 called nicotinamide (NAM) has potential to prevent or treat bone diseases related to oxidative stress by boosting production of anti-oxidant enzymes. Mitochondria, the powerhouses of the cell, produce reactive oxygen species (ROS) during normal metabolism. If these ROS are not countered by enough anti-oxidants, oxidative stress can decrease production of bone-building cells called osteoblasts, leading to bone aging and osteoporosis. Hyun-Mo Ryoo and Woo-Jin Kim at Seoul National University in South Korea and co-workers investigated whether NAM, the precursor of a key mitochondrial molecule, could restore ROS balance. In experiments in bone cells, NAM improved mitochondrial function, boosted anti-oxidant production, and promoted osteoblast formation. NAM prevented and repaired oxidative damage in bone cells and therefore shows potential both as a preventative and therapeutic treatment for bone health.
Journal Article
Which Income Inequality Influences Which Health Indicators? Analysis of the Income Inequality Hypothesis with Market and Disposable Gini Indicators
2019
Recent cross-national health studies growingly refute the income inequality hypothesis on the relationship between income inequality and aggregate health after adjusting for control variables with updated international datasets. Few of them, however, use a market income inequality indicator as an independent variable. While the latter measures the exact amounts pocketed by each individual, the former could be related to an individual’s social or economic status. The pooled TSCS regression for the selected 26 industrialized nations over 1995–2010 test the hypothesis with three different income inequality indicators: disposable and market income Gini and ‘tax and transfer effect’. We used the OECD dataset. The disposable income inequality does not have a statistically significant relationship with any of the health indicators except for infant mortality. The market income Gini does have a statistically significant association only with female life expectancy. The relationship between income inequality indicators and health outcomes are dynamic and not consistent.
Journal Article
Sex differences in the genetic architecture of depression
2020
The prevalence and clinical characteristics of depressive disorders differ between women and men; however, the genetic contribution to sex differences in depressive disorders has not been elucidated. To evaluate sex-specific differences in the genetic architecture of depression, whole exome sequencing of samples from 1000 patients (70.7% female) with depressive disorder was conducted. Control data from healthy individuals with no psychiatric disorder (n = 72, 26.4% female) and East-Asian subpopulation 1000 Genome Project data (n = 207, 50.7% female) were included. The genetic variation between men and women was directly compared using both qualitative and quantitative research designs. Qualitative analysis identified five genetic markers potentially associated with increased risk of depressive disorder in females, including three variants (rs201432982 within
PDE4A
, and rs62640397 and rs79442975 within
FDX1L
) mapping to chromosome 19p13.2 and two novel variants (rs820182 and rs820148) within
MYO15B
at the chromosome 17p25.1 locus. Depressed patients homozygous for these variants showed more severe depressive symptoms and higher suicidality than those who were not homozygotes (i.e., heterozygotes and homozygotes for the non-associated allele). Quantitative analysis demonstrated that the genetic burden of protein-truncating and deleterious variants was higher in males than females, even after permutation testing. Our study provides novel genetic evidence that the higher prevalence of depressive disorders in women may be attributable to inherited variants.
Journal Article
Plausibility of the zebrafish embryos/larvae as an alternative animal model for autism: A comparison study of transcriptome changes
2018
Autism spectrum disorder (ASD) is a serious neurodevelopmental disorder characterized by impaired or abnormal social interaction and communication and by restricted and repetitive behaviour. ASD is highly prevalent in Asia, Europe, and the United States, and the frequency of ASD is growing each year. Recent epidemiological studies have indicated that ASD may be caused or triggered by exposure to chemicals in the environment, such as those in the air or water. Thus, toxicological studies are needed to examine chemicals that might be implicated. However, the experimental efficiency of existing experimental models is limited, and many models represent challenges in terms of animal welfare. Thus, alternative ASD animal models are necessary. To address this, we examined the efficacy of the zebrafish embryo/larva as an alternative model of ASD. Specifically, we exposed zebrafish to valproic acid (0, 12.5, 25, 50, or 100 μM), which is a chemical known to induce autism-like effects. We then analysed subsequent developmental, behavioural, and transcriptomic changes. We found that 100 μM and 50 μM valproic acid decreased the hatching rate and locomotor activity of zebrafish embryos/larvae. Transcriptomic analysis revealed significant alterations in a number of genes associated with autism, such as adsl, mbd5, shank3, and tsc1b. Additionally, we found changes in gene ontology that were also reported in previous studies. Our findings indicate that zebrafish embryos/larvae and humans with ASD might have common physiological pathways, indicating that this animal model may represent an alternative tool for examining the causes of and potential treatments for this illness.
Journal Article