Swd2/Cps35 determines H3K4 tri-methylation via interactions with Set1 and Rad6.

BACKGROUND: Histone H3K4 tri-methylation (H3K4me3) catalyzed by Set1/COMPASS, is a prominent epigenetic mark found in promoter-proximal regions of actively transcribed genes. H3K4me3 relies on prior monoubiquitination at the histone H2B (H2Bub) by Rad6 and Bre1. Swd2/Cps35, a Set1/COMPASS component, has been proposed as a key player in facilitating H2Bub-dependent H3K4me3. However, a more comprehensive investigation regarding the relationship among Rad6, Swd2, and Set1 is required to further understand the mechanisms and functions of the H3K4 methylation. RESULTS: We investigated the genome-wide occupancy patterns of Rad6, Swd2, and Set1 under various genetic conditions, aiming to clarify the roles of Set1 and Rad6 for occupancy of Swd2. Swd2 peaks appear on both the 5' region and 3' region of genes, which are overlapped with its tightly bound two complexes, Set1 and cleavage and polyadenylation factor (CPF), respectively. In the absence of Rad6/H2Bub, Set1 predominantly localized to the 5' region of genes, while Swd2 lost all the chromatin binding. However, in the absence of Set1, Swd2 occupancy near the 5' region was impaired and rather increased in the 3' region. CONCLUSIONS: This study highlights that the catalytic activity of Rad6 is essential for all the ways of Swd2's binding to the transcribed genes and Set1 redistributes the Swd2 to the 5' region for accomplishments of H3K4me3 in the genome-wide level.

Relationship between skin greasiness and cuticular wax in harvested "Hongro" apples.

We investigated the ripening and skin greasiness of "Hongro" apples during storage at 20 °C. Postharvest treatment using 100 µLL-1 ethylene accelerated ripening and increased greasiness, whereas treatment using 1 µLL-1 1-methylcyclopropene delayed ripening and reduced greasiness. Scanning electron microscopy showed changes in cuticular wax structure linked to greasiness. Metabolic analysis identified specific metabolites related to greasiness, which varied upon postharvest treatment. Greasiness was positively associated with ethylene production and butyl-9,12-octadecadienoate content. Random forest modeling predicted greasiness levels with high accuracy, with root mean square error values of 0.322 and 0.362 for training and validation datasets, respectively. These findings illuminate the complex interplay between postharvest treatment, apple ripening, wax composition, and skin greasiness. The application of predictive models exemplifies the potential for technology-driven approaches in agriculture and aids in the development of postharvest strategies to control greasiness and maintain fruit quality.

Dual-targeted nano-encapsulation of neonatal porcine islet-like cell clusters with triiodothyronine-loaded bifunctional polymersomes.

There is growing evidence that neonatal porcine islet-like cell clusters (NPCCs) isolated from piglets can be used to treat type 1 diabetes in humans. However, graft rejection is a common complication in humans owing to the prevalence of xenoantigens in porcine. Therefore, researchers have investigated various islet encapsulation techniques that could protect against these antigens. To this end, this study presents a robust nano-encapsulation method based on bifunctional polymersomes (PSomes), in which N-hydroxysuccinimide (NHS) and maleimide (Mal) groups conjugated to the PSomes terminal interact with the amine and thiol groups on the surface of NPCCs to induce dual targeting via two covalent bonds. The findings indicate that the ratio of NHS to Mal on PSomes is optimal for dual targeting. Moreover, triiodothyronine (T3) is known to promotes pancreatic islet maturation and differentiation of endocrine cells into beta cells. T3 encapsulated in PSomes is shown to increase the glucose sensitivity of NPCCs and enhance insulin secretion from NPCCs. Furthermore, improvements in the nano-encapsulation efficiency and insulin-secreting capability of NPCCs through dual targeting via dual-Psomes are demonstrated. In conclusion, the proposed nano-encapsulation technique could pave the way for significant advances in islet nano-encapsulation and the imprevement of NPCC immaturity via T3 release.

Enhanced Preservation of Climacteric Fruit with a Cellulose Nanofiber-Based Film Coating.

Bananas are a typical climacteric fruit with high respiration and ethylene production rates after harvest, and they show rapid ripening-senescence phenotypes. Here, we demonstrate that carboxymethylcellulose nanofibers (CM-CNFs) and red cabbage extracts (RCE) can be used as a unique film coating formulation for enhancement of the shelf-life of fruit. A CM-CNF suspension solution is created through a process involving chemical modification, followed by mechanical grinding. It has a high aspect ratio that allows for the creation of a thin and transparent film on the surface of bananas. The cross-linked CM-CNF hydrogel forms a dense film layer on the banana surface during dehydration and prevents respiration and weight loss. RCE contains polyphenols acting as antioxidants, which prevent the appearance of black dots on the banana peels. It serves to mitigate the browning of banana skins and also hinders the respiration process, consequently slowing the aging of bananas.

Determination of the Optimal Concentration of Natural Antimicrobial Agents in Marinade Sauce for Meal Kits.

This study aimed to determine the antimicrobial effectiveness of natural antimicrobial agents (NAAs) (yuzu juice, wasabi extract, and rosemary extract) against three target microorganisms (TMs) (Escherichia coli, Staphylococcus aureus, and Salmonella Typhimurium) and to determine the optimal concentration of these agents using response surface methodology (RSM) to ensure the safety of meal kits manufactured using marinade sauce. The three NAAs added to marinade sauce effectively inactivated TMs (P<0.05), in particular, yuzu juice had the greatest antimicrobial effect against TMs, followed by wasabi and rosemary extracts. To determine the optimal concentration of NAAs using RSM, 17 concentrations were tested with three TMs as dependent variables and three NAAs as independent variables. The results showed that E. coli was not present under any of the conditions tested, whereas S. aureus and S. Typhimurium exhibited different characteristics depending on the conditions. Through response surface analysis of the TMs except for E. coli, which was not detected, it was determined that S. aureus had a coefficient of determination (R2) of 0.928 and a lack of fit of 0.074, and the linear regression of [yuzu juice] (X1) and quadratic regression of [yuzu juice]2 (X12) were both significant (P<0.05). S. Typhimurium had an R2 of 0.8955 and a lack of fit of 0.051, and only the quadratic regression of [yuzu juice]2 (X12) was significant (P<0.05). Based on RSM and ridge analysis, the optimal mixed conditions were determined to be 3.92% (v/w) yuzu juice, 23.41% (v/w) wasabi extract, and 3.93% (v/w) rosemary extract. After investigating the antimicrobial effect under the optimal conditions, E. coli and S. Typhimurium were absent, and S. aureus was reduced to 2.50 ± 0.09 log colony-forming units/g after 24 h. The results indicated that mixed treatment with the three NAAs had a more significant antimicrobial effect due to their synergistic properties compared to when used in isolation.

The endoplasmic reticulum: Homeostasis and crosstalk in retinal health and disease.

The endoplasmic reticulum (ER) is the largest intracellular organelle carrying out a broad range of important cellular functions including protein biosynthesis, folding, and trafficking, lipid and sterol biosynthesis, carbohydrate metabolism, and calcium storage and gated release. In addition, the ER makes close contact with multiple intracellular organelles such as mitochondria and the plasma membrane to actively regulate the biogenesis, remodeling, and function of these organelles. Therefore, maintaining a homeostatic and functional ER is critical for the survival and function of cells. This vital process is implemented through well-orchestrated signaling pathways of the unfolded protein response (UPR). The UPR is activated when misfolded or unfolded proteins accumulate in the ER, a condition known as ER stress, and functions to restore ER homeostasis thus promoting cell survival. However, prolonged activation or dysregulation of the UPR can lead to cell death and other detrimental events such as inflammation and oxidative stress; these processes are implicated in the pathogenesis of many human diseases including retinal disorders. In this review manuscript, we discuss the unique features of the ER and ER stress signaling in the retina and retinal neurons and describe recent advances in the research to uncover the role of ER stress signaling in neurodegenerative retinal diseases including age-related macular degeneration, inherited retinal degeneration, achromatopsia and cone diseases, and diabetic retinopathy. In some chapters, we highlight the complex interactions between the ER and other intracellular organelles focusing on mitochondria and illustrate how ER stress signaling regulates common cellular stress pathways such as autophagy. We also touch upon the integrated stress response in retinal degeneration and diabetic retinopathy. Finally, we provide an update on the current development of pharmacological agents targeting the UPR response and discuss some unresolved questions and knowledge gaps to be addressed by future research.

PhoU: a multifaceted regulator in microbial signaling and homeostasis.

Inorganic phosphate (Pi) is a fundamental molecule crucial for numerous biological processes, such as ATP synthesis and phospholipid formation. To prevent cellular toxicity, Pi transport is often linked to counterion transport within the bacterium. This review discusses the multifaceted functions of the PhoU protein in bacterial regulation, focusing on its role in coordinating Pi transport with counterions, controlling polyphosphate accumulation, and regulating secondary metabolite biosynthesis and DNA repair. We also explore recent findings that challenge the conventional view of PhoU simply as a negative regulator in phosphate signaling, suggesting its broader impact on bacterial physiology and stress response. Understanding the diverse functions of PhoU provides new insight into bacterial biology and offers potential therapeutic implications.

Gene Expression of Clusterin, Tissue Inhibitor of Metalloproteinase-1, and Their Receptors in Retinal Pigment Epithelial Cells and Müller Glial Cells Is Modulated by Inflammatory Stresses.

Balanced activities of matrix metalloproteinases (MMPs) and their inhibitors are essential for photoreceptor (PR) cell survival. PR rod cell survival in rodent models of inherited retinitis pigmentosa (RP) is prolonged by recombinant tissue inhibitor of metalloproteinase (TIMP)-1 or clusterin (CLU) proteins. Retinal pigment epithelial cells (RPE) and Müller glia (MG) cells support PR cells. In human RPE and MG cell lines, we measured their mRNA levels of the two genes with quantitative real-time PCR (qRT-PCR) with interleukin (IL)-1ß treatment, a key pathological component in retinal degeneration. Endogenous CLU gene expression was significantly downregulated by IL-1ß in both cell types, whereas TIMP-1 expression was upregulated in MG cells, suggesting the transcriptional control of CLU is potentially more sensitive to inflammatory conditions. The expression levels of CLU endocytic receptors revealed that the low-density lipoprotein receptor-related protein 2 (LRP2) was upregulated only in MG cells by the treatment with no detectable change in RPE cells. Like LRP2, IL-1ß upregulated TIMP-1 receptor LRP1 expression in MG cells; however, it was decreased in the expression of RPE cells. These data suggest that the gene expression of CLU and TIMP-1 and their receptors may be dynamically modulated in inflammatory conditions.

Lysine Ubiquitylation Drives Rhodopsin Protein Turnover.

Rhodopsin is a G-protein-coupled receptor that is specifically and abundantly expressed in rod photoreceptors. Over 150 rhodopsin mutations cause autosomal dominant retinitis pigmentosa (adRP). The most common mutation in the United States is the conversion of proline to histidine at position 23 (P23H) in the N-terminal domain of rhodopsin. We previously found that P23H rhodopsin was misfolded, ubiquitinylated, and rapidly degraded. Here, we investigated the role of lysine residues on P23H rhodopsin ubiquitinylation and turnover. We transfected HEK293 cells with a P23H human rhodopsin construct where all 11 lysine residues were mutated to arginine (K-null P23H). We found that the K-null P23H rhodopsin was significantly less ubiquitylated than intact P23H rhodopsin. We found that K-null P23H protein turnover was significantly slower compared to P23H rhodopsin through cycloheximide chase analysis. Finally, we also generated a wild-type rhodopsin construct where all lysines were converted to arginine and found significantly reduced ubiquitylation. Our findings identify ubiquitinylation of lysine residues as an important posttranslational modification involved in P23H rhodopsin protein degradation.

Shelf Life Prediction of Vacuum-Packaged Grilled Mackerel.

The current study aimed to establish the shelf life of vacuum-packaged grilled mackerel stored at 5, -5, and -20°C for 70 days. To this end, physicochemical analyses, which involved determining the pH, volatile basic nitrogen, amino nitrogen, trimethylamine (TMA), and thiobarbituric acid levels; microbiological analyses (aerobic plate count and coliform); and sensory quality determination were performed. Regression analysis on the relationship between physicochemical properties and storage time at various temperatures revealed TMA level was the most suitable parameter (R2=0.9769) for predicting changes in the quality of grilled mackerel during storage, with a quality limit value of 8.74 mg/100 g. The shelf life of vacuum-packaged grilled mackerel according to temperature was 21, 53, 62, and 75 days for 5, -5, -15, and -20°C, respectively, with the use-by date being 23 days at 5°C and 74 days at -5°C. In conclusion, TMA was the most suitable parameter for predicting changes in the quality of grilled mackerel during storage.

Pumped and pumpless microphysiological systems to study (nano)therapeutics.

Fluidic microphysiological systems (MPS) are microfluidic cell culture devices that are designed to mimic the biochemical and biophysical in vivo microenvironments of human tissues better than conventional petri dishes or well-plates. MPS-grown tissue cultures can be used for probing new drugs for their potential primary and secondary toxicities as well as their efficacy. The systems can also be used for assessing the effects of environmental nanoparticles and nanotheranostics, including their rate of uptake, biodistribution, elimination, and toxicity. Pumpless MPS are a group of MPS that often utilize gravity to recirculate cell culture medium through their microfluidic networks, providing some advantages, but also presenting some challenges. They can be operated with near-physiological amounts of blood surrogate (i.e., cell culture medium) that can recirculate in bidirectional or unidirectional flow patterns depending on the device configuration. Here we discuss recent advances in the design and use of both pumped and pumpless MPS with a focus on where pumpless devices can contribute to realizing the potential future role of MPS in evaluating nanomaterials. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials.

Membrane-Bound Protease FtsH Protects PhoP from the Proteolysis by Cytoplasmic ClpAP Protease in Salmonella Typhimurium.

Among the AAA+ proteases in bacteria, FtsH is a membrane-bound ATP-dependent metalloprotease, which is known to degrade many membrane proteins as well as some cytoplasmic proteins. In the intracellular pathogen Salmonella enterica serovar Typhimurium, FtsH is responsible for the proteolysis of several proteins including MgtC virulence factor and MgtA/MgtB Mg2+ transporters, the transcription of which is controlled by the PhoP/PhoQ two-component regulatory system. Given that PhoP response regulator itself is a cytoplasmic protein and also degraded by the cytoplasmic ClpAP protease, it seems unlikely that FtsH affects PhoP protein levels. Here we report an unexpected role of the FtsH protease protecting PhoP proteolysis from cytoplasmic ClpAP protease. In FtsH-depleted condition, PhoP protein levels decrease by ClpAP proteolysis, lowering protein levels of PhoP-controlled genes. This suggests that FtsH is required for normal activation of PhoP transcription factor. FtsH does not degrade PhoP protein but directly binds to PhoP, thus sequestering PhoP from ClpAP-mediated proteolysis. FtsH's protective effect on PhoP can be overcome by providing excess ClpP. Because PhoP is required for Salmonella's survival inside macrophages and mouse virulence, these data implicate that FtsH's sequestration of PhoP from ClpAP-mediated proteolysis is a mechanism ensuring the amount of PhoP protein during Salmonella infection.

Standardized Suicide Prevention Program for Gatekeeper Intervention of North Korean Defectors in South Korea.

OBJECTIVE: North Korean defectors (NKDs) have experienced substantial difficulties during the migration and settlement in South Korea. They have a high prevalence of depression, post-traumatic stress disorder, and suicidal behaviors. The high prevalence of mental disorders among NKDs can lead to a high suicide rate. However, there are no suicide prevention programs for NKDs. This study aims to customize a suicide prevention program with content suitable for NKDs' particular circumstances. METHODS: A multidisciplinary research team developed this program based on domestic and international gatekeeper training programs for suicide prevention and articles related to suicide prevention. RESULTS: We developed a multi-part gatekeeper training program, "Suicide CARE for NKDs." In the "Introduction," trainees learn about the need for the program and its importance. In "Careful observation," trainees learn to recognize linguistic, behavioral, and situational signals of suicide risk. In "Active listening," trainees learn how to ask about suicidal thoughts and to listen empathetically. In "Risk evaluation and expert referral," trainees learn to evaluate suicide risk and to connect NKDs with institutes or services. CONCLUSION: We expect this program to become useful for training gatekeepers to prevent suicide among NKD. A future follow-up study is needed to confirm the efficacy of the program.

Effects of Auricular Acupressure on Hip Flexibility and Pain in Taekwondo Participants: Randomized Controlled Trial.

BACKGROUND: In sports, hip flexibility is essential to reduce injuries and improve performance. AIM: This study aimed to examine the effects of auricular acupressure on hip flexibility and pain in Taekwondo participants. METHOD: This randomized controlled trial was performed in the Republic of Korea from January 2021 to August 2021. The Numeric Rating Scale for Pain and Hip Flexibility was used. Twenty-one participants received auricular pressure once weekly for six weeks, while 17 participants did not receive any intervention. Auricular acupressure was applied to the hip (AH13), Shinmun, and auricular acupressure points associated with the pain areas reported by the participants. RESULTS: Auricular acupressure improved hip flexibility (t = 2.67, p = .011) and back pain (t = 2.11, p = .043). The mean difference in post-pretest hip flexibility in the experimental group was 16.24 degrees (±13.63), whereas that in the control group was 4.77 degrees (±15.07). The mean difference in the experimental group's pre-post-test scores of back pain was 1.24 (±2.64), whereas that in the control group was 0.18 (±1.41). CONCLUSIONS: The results of this study showed that auricular acupressure could be used to treat pain and improve hip flexibility.

Mechanical Regulation of Oral Epithelial Barrier Function.

Epithelial cell function is modulated by mechanical forces imparted by the extracellular environment. The transmission of forces onto the cytoskeleton by modalities such as mechanical stress and matrix stiffness is necessary to address by the development of new experimental models that permit finely tuned cell mechanical challenges. Herein, we developed an epithelial tissue culture model, named the 3D Oral Epi-mucosa platform, to investigate the role mechanical cues in the epithelial barrier. In this platform, low-level mechanical stress (0.1 kPa) is applied to oral keratinocytes, which lie on 3D fibrous collagen (Col) gels whose stiffness is modulated by different concentrations or the addition of other factors such as fibronectin (FN). Our results show that cells lying on intermediate Col (3 mg/mL; stiffness = 30 Pa) demonstrated lower epithelial leakiness compared with soft Col (1.5 mg/mL; stiffness = 10 Pa) and stiff Col (6 mg/mL; stiffness = 120 Pa) gels, indicating that stiffness modulates barrier function. In addition, the presence of FN reversed the barrier integrity by inhibiting the interepithelial interaction via E-cadherin and Zonula occludens-1. Overall, the 3D Oral Epi-mucosa platform, as a new in vitro system, will be utilized to identify new mechanisms and develop future targets involved in mucosal diseases.

ClC Chloride Channels in Gram-Negative Bacteria and Its Role in the Acid Resistance Systems.

Pathogenic bacteria that colonize the human intestinal tract have evolved strategies to overcome acidic conditions when they pass through the gastrointestinal tract. Amino acid-mediated acid resistance systems are effective survival strategies in a stomach that is full of amino acid substrate. The amino acid antiporter, amino acid decarboxylase, and ClC chloride antiporter are all engaged in these systems, and each one plays a role in protecting against or adapting to the acidic environment. The ClC chloride antiporter, a member of the ClC channel family, eliminates negatively charged intracellular chloride ions to avoid inner membrane hyperpolarization as an electrical shunt of the acid resistance system. In this review, we will discuss the structure and function of the prokaryotic ClC chloride antiporter of amino acid-mediated acid resistance system.

Manganese Transporter Proteins in Salmonella enterica serovar Typhimurium.

The metal cofactors are essential for the function of many enzymes. The host restricts the metal acquisition of pathogens for their immunity and the pathogens have evolved many ways to obtain metal ions for their survival and growth. Salmonella enterica serovar Typhimurium also needs several metal cofactors for its survival, and manganese has been found to contribute to Salmonella pathogenesis. Manganese helps Salmonella withstand oxidative and nitrosative stresses. In addition, manganese affects glycolysis and the reductive TCA, which leads to the inhibition of energetic and biosynthetic metabolism. Therefore, manganese homeostasis is crucial for full virulence of Salmonella. Here, we summarize the current information about three importers and two exporters of manganese that have been identified in Salmonella. MntH, SitABCD, and ZupT have been shown to participate in manganese uptake. mntH and sitABCD are upregulated by low manganese concentration, oxidative stress, and host NRAMP1 level. mntH also contains a Mn2+-dependent riboswitch in its 5' UTR. Regulation of zupT expression requires further investigation. MntP and YiiP have been identified as manganese efflux proteins. mntP is transcriptionally activated by MntR at high manganese levels and repressed its activity by MntS at low manganese levels. Regulation of yiiP requires further analysis, but it has been shown that yiiP expression is not dependent on MntS. Besides these five transporters, there might be additional transporters that need to be identified.

Recovery of dopaminergic amacrine cells after strobe light stimulation in the developing rat retina.

Concerns regarding the impact of strobe light on human health and life have recently been raised. Sources of strobe light include visual display terminals, light-emitting diodes, and computer monitors. Strobe light exposure leads to visual discomfort, headaches, and poor visual performance and affects the number of dopaminergic amacrine cells (DACs) in the developing retina, as well as retinal dopamine levels in animals. DACs serve as the sole source of retinal dopamine, and dopamine release from the retina is activated by light exposure following a circadian rhythm. Using a Sprague-Dawley rat model, this study sought to determine whether changes in DACs caused by strobe light are recoverable after ceasing strobe light exposure during retinal development. From eye opening (postnatal 2 weeks), rats in the control group were reared under normal light (an unflickering 150 lux incandescent lamp with a 12 h light/dark cycle), whereas those in the experimental group (i.e., strobe-recovery group) were reared under strobe light (2 Hz for 12 h/day) exposure for 2 weeks. After postnatal week 4, normal light was provided to all animals to observe the reversibility of the effect of strobe light. Immunohistochemistry and immunoblot analysis for the rate limiting enzyme for dopamine synthesis, tyrosine hydroxylase (TH), as well as high-pressure liquid chromatography for measuring dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) were performed at postnatal weeks 4, 6, 8, and 10. The number of type I and type II TH-immunoreactive (TH-IR) cells across the entire retina was counted to evaluate whether changes in DACs induced by strobe light could recover after ceasing strobe light exposure. The number of type I TH-IR cells slightly decreased but remained at a constant level in the control group. In contrast, the number of type I TH-IR cells rapidly decreased up to postnatal week 6, but then increased after postnatal week 8 in the strobe-recovery group. Subsequently, the number of type I TH-IR cells eventually reached a number similar to that in the control group. In addition, the number of intermediate-sized TH-IR cells were increased at postnatal weeks 8 and 10 and the dopamine level was decreased at postnatal week 8 in the strobe-recovery group. However, the levels of DOPAC and TH proteins did not differ between the two groups. This suggests that changes in DACs caused by strobe light are reversible and that type II TH-IR cells may play a key role in this recovery.

Mitochondria and Endoplasmic Reticulum Stress in Retinal Organoids from Patients with Vision Loss.

Activating transcription factor 6 (ATF6), a key regulator of the unfolded protein response, plays a key role in endoplasmic reticulum function and protein homeostasis. Variants of ATF6 that abrogate transcriptional activity cause morphologic and molecular defects in cones, clinically manifesting as the human vision loss disease achromatopsia (ACHM). ATF6 is expressed in all retinal cells. However, the effect of disease-associated ATF6 variants on other retinal cell types remains unclear. Herein, this was investigated by analyzing bulk RNA-sequencing transcriptomes from retinal organoids generated from patients with ACHM, carrying homozygous loss-of-function ATF6 variants. Marked dysregulation in mitochondrial respiratory complex gene expression and disrupted mitochondrial morphology in ACHM retinal organoids were identified. This indicated that loss of ATF6 leads to previously unappreciated mitochondrial defects in the retina. Next, gene expression from control and ACHM retinal organoids were compared with transcriptome profiles of seven major retinal cell types generated from recent single-cell transcriptomic maps of nondiseased human retina. This indicated pronounced down-regulation of cone genes and up-regulation in Müller glia genes, with no significant effects on other retinal cells. Overall, the current analysis of ACHM patient retinal organoids identified new cellular and molecular phenotypes in addition to cone dysfunction: activation of Müller cells, increased endoplasmic reticulum stress, disrupted mitochondrial structure, and elevated respiratory chain activity gene expression.

Development and Characterization of Synthetic Norovirus RNA for Use in Molecular Detection Methods.

Background: Reference materials are essential for the quality assurance of molecular detection methods. We developed and characterized synthetic norovirus GI and GII RNA reference materials. Methods: Norovirus GI and GII RNA sequences including the ORF1-ORF2 junction region were designed based on 1,495 reported norovirus sequences and synthesized via plasmid preparation and in vitro transcription. The synthetic norovirus GI and GII RNAs were evaluated using six commercial norovirus detection kits used in Korea and subjected to homogeneity and stability analyses. A multicenter study involving five laboratories and using four commercial real-time PCR norovirus detection assays was conducted for synthetic norovirus RNA characterization and uncertainty measurements. Results: The synthetic norovirus GI and GII RNAs were positively detected using the six commercial norovirus detection kits and were homogeneous and stable for one year when stored at -20°C or -70°C. All data from the five laboratories were within a range of 1.0 log copies/µL difference for each RNA, and the overall mean concentrations for norovirus GI and GII RNAs were 7.90 log copies/µL and 6.96 log copies/µL, respectively. Conclusions: The synthetic norovirus GI and GII RNAs are adequate for quality control based on commercial molecular detection reagents for noroviruses with high sequence variability. The synthetic RNAs can be used as reference materials in norovirus molecular detection methods.