Son H

References (4)

Title : Genetic and Transcriptional Regulatory Mechanisms of Lipase Activity in the Plant Pathogenic Fungus Fusarium graminearum - Kim_2023_Microbiol.Spectr__e0528522
Author(s) : Kim S , Lee J , Park J , Choi S , Bui DC , Kim JE , Shin J , Kim H , Choi GJ , Lee YW , Chang PS , Son H
Ref : Microbiol Spectr , :e0528522 , 2023
Abstract : Lipases, which catalyze the hydrolysis of long-chain triglycerides, diglycerides, and monoglycerides into free fatty acids and glycerol, participate in various biological pathways in fungi. In this study, we examined the biological functions and regulatory mechanisms of fungal lipases via two approaches. First, we performed a systemic functional characterization of 86 putative lipase-encoding genes in the plant-pathogenic fungus Fusarium graminearum. The phenotypes were assayed for vegetative growth, asexual and sexual reproduction, stress responses, pathogenicity, mycotoxin production, and lipase activity. Most mutants were normal in the assessed phenotypes, implying overlapping roles for lipases in F. graminearum. In particular, FgLip1 and Fgl1 were revealed as core extracellular lipases in F. graminearum. Second, we examined the lipase activity of previously constructed transcription factor (TF) mutants of F. graminearum and identified three TFs and one histone acetyltransferase that significantly affect lipase activity. The relative transcript levels of FgLIP1 and FGL1 were markedly reduced or enhanced in these TF mutants. Among them, Gzzc258 was identified as a key lipase regulator that is also involved in the induction of lipase activity during sexual reproduction. To our knowledge, this study is the first comprehensive functional analysis of fungal lipases and provides significant insights into the genetic and regulatory mechanisms underlying lipases in fungi. IMPORTANCE Fusarium graminearum is an economically important plant-pathogenic fungus that causes Fusarium head blight (FHB) on wheat and barley. Here, we constructed a gene knockout mutant library of 86 putative lipase-encoding genes and established a comprehensive phenotypic database of the mutants. Among them, we found that FgLip1 and Fgl1 act as core extracellular lipases in this pathogen. Moreover, several putative transcription factors (TFs) that regulate the lipase activities in F. graminearum were identified. The disruption mutants of F. graminearum-lipase regulatory TFs all showed defects in sexual reproduction, which implies a strong relationship between sexual development and lipase activity in this fungus. These findings provide valuable insights into the genetic mechanisms regulating lipase activity as well as its importance to the developmental stages of this plant-pathogenic fungus.
ESTHER : Kim_2023_Microbiol.Spectr__e0528522
PubMedSearch : Kim_2023_Microbiol.Spectr__e0528522
PubMedID: 37093014

Title : No prominent toxicity of polyethylene microplastics observed in neonatal mice following intratracheal instillation to dams during gestational and neonatal period - Han_2021_Toxicol.Res_37_443
Author(s) : Han Y , Song Y , Kim GW , Ha C , Lee J , Kim M , Son H , Lee G , Gautam R , Heo Y
Ref : Toxicol Res , 37 :443 , 2021
Abstract : Microplastics (MPs) have been recently recognized as a global environmental threat and its exposure as a risk factor to human health. Health effects through MPs exposure have been recently reported, especially through oral route of exposure. Since MPs could be exposed to humans through routes other than oral, this study was designed to evaluate whether MPs exposed through the inhalation route could be delivered to fetal mice and exhibit systemic toxicity. Polyethylene (PE) with 10-45 microm diameter were administered at 0 (distilled water, vehicle control), 6 (low administration), and 60 (high administration) microg/mouse/day to 3 pregnant dams per group from gestational day 9 to postnatal day (PND) 7 through intratracheal instillation. Dams and neonates were sacrificed at PND 7 and blood was collected. Various neonatal organs including brain, lung, heart, stomach, intestine, kidneys, and ovaries were collected for histopathological observation and weight measurement. No influence of PE-MPs administration was observed on the number of offsprings born, but the body and organs' weight were heavier overall in the high administration group of dams and neonates than the other groups with statistical significance achieved in the heart and spleen weight. Level of serum acetylcholinesterase and glutathione peroxidase activity was decreased in the high administration group of dams and neonates compared with the other groups. Lung was the organ with highest number of PE-MPs present in the both administration groups of dams, and PE-MPs were also detected in liver and intestine of the high administration dams. Whereas, PND7 neonates showed accountable numbers of PE-MPs only in kidneys of the high administration group. Overall, the present study indicates that PE-MPs instilled intratracheally could be delivered to neonates from dams. Even though adverse effects from PE-MPs exposure during pregnant and lactational period are less prominent on both dam and neonate, potential of second-generation toxicity could be considered for further investigation.
ESTHER : Han_2021_Toxicol.Res_37_443
PubMedSearch : Han_2021_Toxicol.Res_37_443
PubMedID: 34631501

Title : Decomposition of the PET Film by MHETase Using Exo-PETase Function - Sagong_2020_ACS.Catal_10_48050
Author(s) : Sagong HY , Seo H , Kim T , Son H , Joo S , Lee S , Kim S , Woo JS , Hwang S , Kim KJ
Ref : ACS Catal , 10 :4805 , 2020
Abstract : Monohydroxyethyl terephthalate (MHET) hydrolase (MHETase) is an enzyme known to be involved in the final degradation step of poly(ethylene terephthalate) (PET) by hydrolyzing MHET into terephthalic acid and ethylene glycol in Ideonella sakaiensis. Here, we report the extracellular production of MHETase in an active form with a proper folding. Based on the structural observations and biochemical experiments, we reveal that MHETase also functions as exo-PETase by hydrolyzing the synthesized PET pentamer. We further present that MHETase has a hydrolysis activity against the termini-generated PET film, demonstrating the exo-PETase function of the enzyme. We also develop a MHETase R411K/S416A/F424I variant with a higher BHET activity, and the variant exhibits an enhanced degradation activity against the PET film. Based on these results, we propose that MHETase plays several roles in the biodegradation of PET using the BHETase and exo-PETase activities as well as the MHET hydrolysis function
ESTHER : Sagong_2020_ACS.Catal_10_48050
PubMedSearch : Sagong_2020_ACS.Catal_10_48050
PubMedID:
Gene_locus related to this paper: idesa-mheth

Title : A selective role of calcineurin aalpha in synaptic depotentiation in hippocampus - Zhuo_1999_Proc.Natl.Acad.Sci.U.S.A_96_4650
Author(s) : Zhuo M , Zhang W , Son H , Mansuy I , Sobel RA , Seidman J , Kandel ER
Ref : Proc Natl Acad Sci U S A , 96 :4650 , 1999
Abstract : Pharmacological studies have suggested that long-term potentiation (LTP) and long-term depression (LTD) and depotentiation, three forms of synaptic plasticity in the hippocampus, require the activity of the phosphatase calcineurin. At least two different isoforms of calcineurin are found in the central nervous system. To investigate whether all of these forms of synaptic plasticity require the same isoforms of calcineurin, we have examined LTD, depotentiation, and LTP in mice lacking the predominant calcineurin isoform in the central nervous system, Aalpha-/- mice. Depotentiation was abolished completely whereas neither LTD nor LTP were affected. These studies provide genetic evidence that the Aalpha isoform of calcineurin is important for the reversal of LTP in the hippocampus and indicate that depotentiation and LTD operate through somewhat different molecular mechanisms.
ESTHER : Zhuo_1999_Proc.Natl.Acad.Sci.U.S.A_96_4650
PubMedSearch : Zhuo_1999_Proc.Natl.Acad.Sci.U.S.A_96_4650
PubMedID: 10200317