Description of Roseibium sediminicola sp. nov. Isolated from Sediment of a Tidal Flat on the Yellow Sea Coast.

A Gram-stain-negative, aerobic, rod-shaped, motile, flagellated bacterial strain, designated as CAU 1639T, was isolated from the tidal flat sediment on the Yellow Sea in the Republic of Korea. Growth of the isolate was observed at 20-37 °C, at pH 5.0-10.5 and with 0-7% (w/v) NaCl. The genomic DNA G + C content was 60.8%. Phylogenetic analysis, grounded on 16S rRNA gene sequencing, revealed that strain CAU 1639T was closely related to species within the genus Roseibium. It shared the highest similarity with Roseibium album CECT 5095T, followed by Roseibium aggregatum IAM 12614T and Roseibium salinum Cs25T, with 16S rRNA gene sequence similarity ranging from 98.0-98.4%. It was observed that the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values ranged between 72.5-79.5 and 20.0-22.9%, respectively. The polyphasic taxonomic analysis reveals that strain CAU 1639T represents a novel species in the genus Roseibium with the proposed name Roseibium sediminicola sp. nov. The type strain is CAU 1639T (= KCTC 82430T = MCCC 1K06081T).

Electrochemical production of hydroxylamine from nitrate on metal electrodes: A comparative study of selectivity and efficiency.

Despite the great potential of electrochemical nitrate reduction as a hydroxylamine production method, this strategy has not been sufficiently examined, and the effects of electrode material type on the selectivity and efficiency of this reduction remain underexplored. To bridge this gap, the present study evaluated six metals (Ag, Cu, Ni, Sn, Ti, and Zn) as cathode materials for the electrochemical reduction of nitrate to hydroxylamine, showing that the selectivity of hydroxylamine production was maximal for Sn, while the corresponding faradaic and energy utilization efficiencies were maximal for Ti. Although all tested materials favored nitrate reduction over hydrogen evolution, the disparity in the onset potentials of these reactions did not adequately explain the variations in nitrate removal efficiency, which was found to be influenced by material resistance and charge-transfer properties. The rate constants of elementary nitrate reduction steps determined from the time-dependent concentrations of nitrate and its reduction products (nitrous acid, hydroxylamine, and ammonium) were used to calculate the selectivity and efficiency of hydroxylamine production for each electrode. In turn, these selectivities and efficiencies were correlated with the density functional theory-computed adsorption energies of a key hydroxylamine precursor on different electrodes to afford a volcano-type plot with Ti and Sn at its pinnacle. Thus, this study introduces valuable descriptors and methods for the further screening of electrocatalysts for hydroxylamine generation and the establishment of more environmentally friendly hydroxylamine production techniques utilizing sustainable electricity.

Deep learning-based, fully automated, pediatric brain segmentation.

The purpose of this study was to demonstrate the performance of a fully automated, deep learning-based brain segmentation (DLS) method in healthy controls and in patients with neurodevelopmental disorders, SCN1A mutation, under eleven. The whole, cortical, and subcortical volumes of previously enrolled 21 participants, under 11 years of age, with a SCN1A mutation, and 42 healthy controls, were obtained using a DLS method, and compared to volumes measured by Freesurfer with manual correction. Additionally, the volumes which were calculated with the DLS method between the patients and the control group. The volumes of total brain gray and white matter using DLS method were consistent with that volume which were measured by Freesurfer with manual correction in healthy controls. Among 68 cortical parcellated volume analysis, the volumes of only 7 areas measured by DLS methods were significantly different from that measured by Freesurfer with manual correction, and the differences decreased with increasing age in the subgroup analysis. The subcortical volume measured by the DLS method was relatively smaller than that of the Freesurfer volume analysis. Further, the DLS method could perfectly detect the reduced volume identified by the Freesurfer software and manual correction in patients with SCN1A mutations, compared with healthy controls. In a pediatric population, this new, fully automated DLS method is compatible with the classic, volumetric analysis with Freesurfer software and manual correction, and it can also well detect brain morphological changes in children with a neurodevelopmental disorder.

Transcriptional control of motor pool formation and motor circuit connectivity by the LIM-HD protein Isl2.

The fidelity of motor control requires the precise positional arrangement of motor pools and the establishment of synaptic connections between them. During neural development in the spinal cord, motor nerves project to specific target muscles and receive proprioceptive input from these muscles via the sensorimotor circuit. LIM-homeodomain transcription factors are known to play a crucial role in successively restricting specific motor neuronal fates. However, their exact contribution to limb-based motor pools and locomotor circuits has not been fully understood. To address this, we conducted an investigation into the role of Isl2, a LIM-homeodomain transcription factor, in motor pool organization. We found that deletion of Isl2 led to the dispersion of motor pools, primarily affecting the median motor column (MMC) and lateral motor column (LMC) populations. Additionally, hindlimb motor pools lacked Etv4 expression, and we observed reduced terminal axon branching and disorganized neuromuscular junctions in Isl2-deficient mice. Furthermore, we performed transcriptomic analysis on the spinal cords of Isl2-deficient mice and identified a variety of downregulated genes associated with motor neuron (MN) differentiation, axon development, and synapse organization in hindlimb motor pools. As a consequence of these disruptions, sensorimotor connectivity and hindlimb locomotion were impaired in Isl2-deficient mice. Taken together, our findings highlight the critical role of Isl2 in organizing motor pool position and sensorimotor circuits in hindlimb motor pools. This research provides valuable insights into the molecular mechanisms governing motor control and its potential implications for understanding motor-related disorders in humans.

Proficiency versus lexical processing efficiency as a measure of L2 lexical quality: Individual differences in word-frequency effects in L2 visual word recognition.

This study investigated Korean-English second language (L2) speakers' recognition of high- and low-frequency English words and compared two individual difference measures in their role of representing lexical quality in L2: cloze test scores and inverse efficiency scores (IES; response latency corrected for the amount of errors committed), obtained from lexical decision on a separate set of words. Cloze test scores aimed to assess general L2 proficiency, whereas IES was purported to measure lexical processing efficiency. 109 adult Korean-English L2 speakers participated in the study. Results showed significant main effects of word frequency, cloze test scores, and IES on lexical decision times, replicating previous findings and confirming the predictions of the lexical quality hypothesis. Crucially, IES was revealed to be a better measure of individual differences in L2 lexical quality than were cloze test scores. These findings suggest that lexical quality (which can be operationalized in terms of online lexical processing efficiency) comprises a distinct subdomain of language skills on its own, which cannot be measured in full using conventional language proficiency tests.

Gracilimonas sediminicola sp. nov., a moderately halotolerant bacterium isolated from seaweed sediment collected in the East Sea, Republic of Korea.

A Gram-stain-negative, aerobic, rod-shaped bacterium, designated as strain CAU 1638T, was isolated from seaweed sediment collected in the Republic of Korea. The cells of strain CAU 1638T grew at 25-37 °C (optimum, 30 °C), at pH 6.0-7.0 (optimum, pH 6.5) and in the presence of 0-10% NaCl (optimum, 2 %). The cells were positive for catalase and oxidase and did not hydrolyse starch and casein. Strain CAU 1638T was most closely related to Gracilimonas amylolytica KCTC 52885T (97.7 %), followed by Gracilimonas halophila KCTC 52042T (97.4 %), Gracilimonas rosea KCCM 90206T (97.2 %), Gracilimonas tropica KCCM 90063T and Gracilimonas mengyeensis DSM 21985T (97.1 %), as revealed by 16S rRNA gene sequencing. MK-7 was the major isoprenoid quinone, and iso-C15  : 0 and C15  : 1 ω6c were the major fatty acids. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, two unidentified lipids, two unidentified glycolipids and three unidentified phospholipids. The G+C content of the genome was 44.2 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain CAU 1638T and the reference strains were 73.1-73.9 % and 18.9-21.5  %, respectively. Based on its phylogenetic, phenotypic and chemotaxonomic features, strain CAU 1638T represents a novel species of the genus Gracilimonas, for which the name Gracilimonas sediminicola sp. nov. is proposed. The type strain is CAU 1638T (=KCTC 82454T=MCCC 1K06087T).

Description of Defluviimonas salinarum sp. nov. with the potential of benzene-degradation isolated from saltern in the Yellow Seacoast.

Strain CAU 1641T was isolated from saltern collected in Ganghwa Island, Republic of Korea. The bacterium was an aerobic, Gram-negative, catalase-positive, oxidase-positive, motile, and rod-shaped bacterium. Cell of strain CAU 1641T could grow at 20-40°C and pH 6.0-9.0 with 1.0-3.0% (w/v) NaCl. Stain CAU 1641T shared high 16S rRNA gene sequence similarities with Defluviimonas aquaemixtae KCTC 42108T (98.0%), Defluviimonas denitrificans DSM 18921T (97.6%), and Defluviimonas aestuarii KACC 16442T (97.5%). Phylogenetic trees based on the 16S rRNA gene and the core-genome sequences indicated that strain CAU 1641T belonged to genus Defluviimonas. Strain CAU 1641T contained ubiquinone-10 (Q-10) as the sole respiratory quinone and and summed feature 8 (C18:1ω6c and/or C18:1ω7c) as the predominant fatty acid (86.1%). The pan-genome analysis indicated that the genomes of the strain CAU 1641T and 15 reference strains contain a small core genome. The Average Nucleotide Identity and digital DNA-DNA hybridization values among strain CAU 1641T and reference strains of the genus Defluviimonas were in the range of 77.6%-78.8% and 21.1-22.1%, respectively. The genome of strain CAU 1641T has several genes of benzene degradation. The genomic G + C content was 66.6%. Based on polyphasic and genomic analyses, strain CAU 1641T represents a novel species of the genus Defluviimonas, for which the name Defluviimonas salinarum sp. nov., is proposed. The type strain is CAU 1641T ( = KCTC 92081T = MCCC 1K07180T).

Characterization of a Potential Probiotic Lactiplantibacillus plantarum LRCC5310 by Comparative Genomic Analysis and its Vitamin B6 Production Ability.

Safety assessment and functional analysis of probiotic candidates are important for their industrial applications. Lactiplantibacillus plantarum is one of the most widely recognized probiotic strains. In this study we aimed to determine the functional genes of L. plantarum LRCC5310, isolated from kimchi, using next-generation, whole-genome sequencing analysis. Genes were annotated using the Rapid Annotations using Subsystems Technology (RAST) server and the National Center for Biotechnology Information (NCBI) pipelines to establish the strain's probiotic potential. Phylogenetic analysis of L. plantarum LRCC5310 and related strains showed that LRCC5310 belonged to L. plantarum. However, comparative analysis revealed genetic differences between L. plantarum strains. Carbon metabolic pathway analysis based on the Kyoto Encyclopedia of Genes and Genomes database showed that L. plantarum LRCC5310 is a homofermentative bacterium. Furthermore, gene annotation results indicated that the L. plantarum LRCC5310 genome encodes an almost complete vitamin B6 biosynthetic pathway. Among five L. plantarum strains, including L. plantarum ATCC 14917T, L. plantarum LRCC5310 detected the highest concentration of pyridoxal 5'-phosphate with 88.08 ± 0.67 nM in MRS broth. These results indicated that L. plantarum LRCC5310 could be used as a functional probiotic for vitamin B6 supplementation.

Photoredox Selective Homocoupling of Propargyl Bromides.

Since the alkynyl moiety is one of the most versatile synthons for many other functional groups, 1,5-diynes (Wurtz-type products of propargyl halides) would be valuable synthetic building blocks for the synthesis of complex functional molecules. However, despite the high and similar reactivity of propargyl radicals compared to allyl and benzyl derivative radicals, a photoredox Wurtz-type reaction of propargyl halides has not yet been developed. In this study, we developed the visible-light-induced selective homocoupling of propargyl bromides to form 1,5-diynes. Electrochemical and photophysical experiments showed that the key propargyl radical generation involves a reductive quenching cycle of the photoexcited [Ir(III)]* photocatalyst in the presence of N,N-dicyclohexylmethylamine. The product 1,5-diyne underwent one-step conversion to the functionalized indole derivative via Rh-catalyzed coupling with N-phenylacetamide. These results indicated the high utility of the developed homocoupling method.

Evaluation of Intervention Policies for the COVID-19 Epidemic in the Seoul/Gyeonggi Region through a Model Simulation.

PURPOSE: To evaluate the efficacy of intervention policies on coronavirus disease-19 (COVID-19) dissemination. MATERIALS AND METHODS: An age-structured compartmental model for the COVID-19 outbreak was proposed to predict the impact of control measures in the Seoul/Gyeonggi region. The model was calibrated based on actual data and realistic situations, including daily vaccine doses, proportion of delta variant cases, and confirmed cases by age. We simulated different scenarios for non-pharmaceutical interventions by varying social distancing and school attendance strategies. RESULTS: Two-step mitigation of social distancing without in-person classes would result in a rapid increase in confirmed cases up to 10000 but would keep severe cases within the manageable range of the health care system. The overall impact of taking down the distancing level by one step with twice the increase in contacts at school was comparable to the above scenario. Implementation of two-step mitigation of social distancing along with a two-fold increase in contacts among the school-age group would dramatically increase confirmed and severe cases by over 80000 and 100, respectively, as early as the beginning of December. This policy would cause the situation to spiral out of control, considering the scale of the response and time to prepare. On the other hand, the burden on the current healthcare system caused by two-step mitigation of social distancing and 40% increased contacts in the school-age group was manageable if prepared. CONCLUSION: A compromise between social distancing and school attendance policy and timely preparations for the spread of COVID-19 are required.

Photocatalytic para-Selective C-H Functionalization of Anilines with Diazomalonates.

Visible-light-induced para-selective C-H functionalization of anilines over N-H insertion was developed using diazomalonates with the help of an Ir(III) photocatalyst. The para-selective radical-radical cross coupling proceeded via C-centered radical intermediates generated from both anilines and diazomalonates. The photochemistry of anilines could be extended to other N-heterocycles, such as indole and carbazole. The reaction pathway for the selective C-C coupling was validated by electrochemical and photophysical experiments as well as computational studies.

Halomarinibacterium sedimenti gen. nov., sp. nov., a carotenoid pigment-producing bacterium isolated from marine sediment.

A Gram-negative, strictly aerobic, non-motile, rod-shaped bacterial strain CAU 1614T was isolated from a marine sediment sample collected in the Republic of Korea. Optimal growth of strain CAU 1614T proceeded at 30 °C, pH 7.0, and 2% (w/v) NaCl. 16S rRNA gene similarity was lower than 94.5% with genera Aureisphaera, Marinirhabdus, Aureitalea, Gilvibacter, Ulvibacter, and Jejudonia. The highest similarity was with Aureisphaera galaxeae 04OKA003-7T (94.5%). The major cellular fatty acids were iso-C15:0, iso-C16:0, iso-C15:1 G, iso-C16:0 3-OH, and iso-C17:0 3-OH and the predominant menaquinone was MK-6. The polar lipids were phosphatidylethanolamine, phosphoglycolipid, an unidentified lipid, two unidentified aminolipids, and an unidentified glycolipid. The draft genome of strain CAU 1614T was 3.9 Mb and DNA G+C content was 36.0 mol%. On the basis of the phenotypic, chemotaxonomic, and genomic data, strain CAU 1614T presents a novel genus in the family Flavobacteriaceae, for which the name Halomarinibacterium sedimenti gen. nov., sp. nov. is proposed. The type strain is CAU 1614T (= KCTC 82457T = MCCC 1K06083T).

Marinobacterium arenosum sp. nov., isolated from a coastal sand.

A Gram-negative, aerobic, motile, rod-shaped bacterium, designated strain CAU 1594T, was isolated from a coastal sand sample collected in the Republic of Korea. Cells of strain CAU 1594T grew best at 30 °C, pH 7.5, and in the presence of 1% (w/v) NaCl. Phylogenetic analysis, based on 16S rRNA gene sequencing, indicated that strain CAU 1594T was affiliated with the genus Marinobacterium and most similar to Marinobacterium jannaschii ATCC 27135T (95.1%) and Marinobacterium stanieri ATCC 27130T (94.9%). The whole genome of strain CAU 1594T was 4,917,683 bp, including 4,188 CDSs, with a 60.4 mol% G + C content. Based on draft genome sequences, the average nucleotide identity and digital DNA-DNA hybridization values of strain CAU 1594T were within the ranges of 71.9-73.1% and 20.0-2.1%, respectively, compared to reference strains. The major respiratory quinone was ubiquinone-8, and the major fatty acids were C16:0, summed feature 3 (C16:1 ω6c and C16:1 ω7c), and summed feature 8 (C18:1 ω6c and C18:1 ω7c). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. Based on these results, strain CAU 1594T represents a novel species of the genus Marinobacterium, for which the name Marinobacterium arenosum sp. nov. is proposed. The type strain is CAU 1594T (=KCTC 82405T=MCCC 1K05672T).

Modeling axonal regeneration by changing cytoskeletal dynamics in stem cell-derived motor nerve organoids.

Oxidative stress triggers axon degeneration and cell death, leading to the development of neurodegenerative diseases. Spinal motor nerves project very long axons, increasing the burden on axonal transport and metabolism. As such, spinal motor nerves are expected to be susceptible to oxidative stress, but model systems for visualizing and investigating acutely degenerating motor axons are limited. In this study, we establish motor nerve organoids from human pluripotent stem cells (hPSCs) with properties similar to those of neuromesodermal progenitors (NMPs), a population of progenitor cells that comprise the caudal spinal cord. Three-dimensional differentiation of organoids efficiently gave rise to mature motor neurons within 18 days. Adherent organoids showed robust axon fascicles and active growth cones under normal conditions. In addition, more homogenous and efficient generation of motor neurons were achieved when organoids were dissociated into individual cells. Hydrogen peroxide-induced oxidative stress resulted in a broad range of signs of axon degeneration including the disappearance of growth cones and neurites, axon retraction, axon fragmentation and bleb formation, and apoptotic cell death, whose severity can be reliably quantifiable in our culture system. Remarkably, cytoskeletal drugs modulating actin or microtubule turnover differentially facilitated axon dynamics and increased axon regenerative potential. Taken together, our motor nerve organoid model could be potentially useful for drug screens evaluating the rearrangement of cytoskeletons in regenerating motor axons.

Sneathiella sedimenti sp. nov., isolated from marine sediment.

A novel bacterium, designated CAU 1612T, was isolated from coastal sediment sampled in the Republic of Korea. Cells of the strain were Gram-stain-negative, rod-shaped and motile. Optimum growth occurred at 30 °C, at pH 7.0 and with 1.0 % (w/v) NaCl. Based on 16S rRNA gene sequences, phylogenetic analysis revealed that strain CAU 1612T belonged to the genus Sneathiella and showed highest similarity to 'Sneathiella litorea' JCM 33810T (98.5 %), followed by Sneathiella chungangensis KCTC 32476T (97.7 %), Sneathiella aquimaris KCTC 12842T (96.0 %), Sneathiella chinensis LMG 23452T (95.5 %), Sneathiella limimaris KCTC 52846T (95.5 %) and Sneathiella glossodoripedis KCTC 12842T (95.4 %). The average nucleotide identity and digital DNA-DNA hybridization values of strain CAU 1612T were estimated to be 68.5-81.7 % and ≤23.7 %, respectively, to members of the genus Sneathiella. The DNA G+C content was 54.1 mol%. The major cellular fatty acids (>10 %) were C16:0, C19 : 0 cyclo ω8c and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The major menaquinone was Q-10 and the predominant polar lipids were phosphatidylmethylethanolamine, phosphatidylethanolamine and phosphatidylglycerol. On the basis of taxonomic evidence, strain CAU 1612T represents a novel species, for which the name Sneathiella sedimenti sp. nov. is proposed. The type strain is CAU 1612T (=KCTC 82427T=MCCC 1K06082T).

Marinobacter arenosus sp. nov., a halotolerant bacterium isolated from a tidal flat.

A Gram-negative, rod-shaped, motile bacterium, designated strain CAU 1620T, was isolated from a tidal flat sediment in Incheon, Republic of Korea. Strain CAU 1620T grew optimally at 30 °C and pH 8.0 in the presence of 6.0% (w/v) NaCl. The results of 16S rRNA gene sequence analysis revealed that strain CAU 1620T showed the highest similarity to Marinobacter adhaerens DSM 23420T (98.5%), followed by Marinobacter algicola DSM 16394T (98.3%) and Marinobacter maroccanus LMG 30465T (98.2%). The average nucleotide identity and digital DNA-DNA hybridisation values between strain CAU 1620T and related strains were estimated as 75.6-78.1% and 19.5-20.9%, respectively. The DNA G + C content based on the draft genome sequence was 59.2%, and the major respiratory quinone was ubiquinone-9. The predominant cellular fatty acids were C12:0, C16:0, C18:1 ω9c, and C12:0 3OH. The predominant polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, and phosphatidylglycerol. According to phenotypic, genotypic, and chemotaxonomic analyses, strain CAU 1620T represents a novel species of the genus Marinobacter, for which the name Marinobacter arenosus sp. nov. is proposed. The type strain is CAU 1620T (= KCTC 82431T = MCCC 1K06079T).

Complete Genome Sequence of Lacticaseibacillus rhamnosus CAU 1365, Isolated from Kimchi.

Here, we report the whole-genome sequence of Lacticaseibacillus rhamnosus CAU 1365, which was isolated from kimchi. The genome was composed of 1 contig with a total length of 2,991,039 bp and had 2,658 coding sequences, including 62 tRNA genes and 15 rRNA genes.

Lactiplantibacillus plantarum LRCC5314 includes a gene for serotonin biosynthesis via the tryptophan metabolic pathway.

As the functions of probiotics within the same species may not be shared, it is important to analyze the genetic characteristics of strains to determine their safety and usefulness before industrial applications. Hence the present study was undertaken to determine functional genes, and beneficial activities of strain LRCC5314, a bacterial strain isolated from kimchi through comparative genomic analysis. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain LRCC5314 was a member of the species L. plantarum. Whole genome size of strain LRCC5314 was sequence was 3.25 Mb long, with a G + C content of 44.5 mol% and 3,031 predicted genes. Strain LRCC5314 could metabolize hexoses through homofermentation, which produces only lactic acid from hexoses. According to gene annotation, strain LRCC-5314 contained genes of EPS production and CRISPR. Moreover, the strain contained genes that could encode a complete biosynthetic pathway for the production of tryptophan, which can be used as a precursor of serotonin. Notably, the tryptophan and serotonin activities strain LRCC5314 were higher than those of reference strains, L. plantarum ATCC 14917T, DSM 20246, DSM 2601, and ATCC 8014, which reach tryptophan amount of 0.784 ± 0.045 µM/ml in MRS broth and serotonin concentration of 19.075 ± 0.295 ng/ml in HT-22 cells. These findings indicated that L. plantarum LRCC5314 could provide a source for serotonin production and could be used as a functional probiotic for stress regulation.

Sustainable radical approaches for cross electrophile coupling to synthesize trifluoromethyl- and allyl-substituted tert-alcohols.

Trifluoromethylated molecules have gained privileged recognition among the medicinal and pharmaceutical chemists. Sustainable photoredox- and electrochemical processes were employed to facilitate the relatively less explored radical cross-electrophile coupling to access trifluoromethyl- and allyl-substituted tert-alcohols. Reactions proceed through trifluoromethyl ketyl radical and allyl radical intermediates, which undergo challenging radical-radical cross-coupling. The developed transformations are mild and chemo-selective to give cross-coupled products and deliver a wide range of valuable trifluoromethyl- and allyl-containing tertiary alcohols. Both processes can also be applied for the synthesis of amine variant containing trifluoromethyl and allyl moiety, which is considered as amide bioisostere.

Estimation of the reproduction number of influenza A(H1N1)pdm09 in South Korea using heterogeneous models.

BACKGROUND: The reproduction number is one of the most crucial parameters in determining disease dynamics, providing a summary measure of the transmission potential. However, estimating this value is particularly challenging owing to the characteristics of epidemic data, including non-reproducibility and incompleteness. METHODS: In this study, we propose mathematical models with different population structures; each of these models can produce data on the number of cases of the influenza A(H1N1)pdm09 epidemic in South Korea. These structured models incorporating the heterogeneity of age and region are used to estimate the reproduction numbers at various terminal times. Subsequently, the age- and region-specific reproduction numbers are also computed to analyze the differences illustrated in the incidence data. RESULTS: Incorporation of the age-structure or region-structure allows for robust estimation of parameters, while the basic SIR model provides estimated values beyond the reasonable range with severe fluctuation. The estimated duration of infectious period using age-structured model is around 3.8 and the reproduction number was estimated to be 1.6. The estimated duration of infectious period using region-structured model is around 2.1 and the reproduction number was estimated to be 1.4. The estimated age- and region-specific reproduction numbers are consistent with cumulative incidence for corresponding groups. CONCLUSIONS: Numerical results reveal that the introduction of heterogeneity into the population to represent the general characteristics of dynamics is essential for the robust estimation of parameters.