Gelatin Nanoparticles can Improve Pesticide Delivery Performance to Plants.

Nanomaterials associated with plant growth and crop cultivation revolutionize traditional concepts of agriculture. However, the poor reiterability of these materials in agricultural applications necessitates the development of environmentally-friendly approaches. To address this, biocompatible gelatin nanoparticles (GNPs) as nanofertilizers with a small size (≈150 nm) and a positively charged surface (≈30 mV) that serve as a versatile tool in agricultural practices is designed. GNPs load agrochemical agents to improve maintenance and delivery. The biocompatible nature and small size of GNPs ensure unrestricted nutrient absorption on root surfaces. Furthermore, when combined with pesticides, GNPs demonstrate remarkable enhancements in insecticidal (≈15%) and weed-killing effects (≈20%) while preserving the efficacy of the pesticide. That GNPs have great potential for use in sustainable agriculture, particularly in inducing plant growth, specifically plant root growth, without fertilization and in enhancing the functions of agrochemical agents is proposed. It is suggested conceptual applications of GNPs in real-world agricultural practices.

Arabidopsis thaliana ubiquitin-associated protein 2 (AtUAP2) functions as an E4 ubiquitin factor and negatively modulates dehydration stress response.

E4, a ubiquitin (Ub) chain assembly factor and post-translational modification protein, plays a key role in the regulation of multiple cellular functions in plants during biotic or abiotic stress. We have more recently reported that E4 factor AtUAP1 is a negative regulator of the osmotic stress response and enhances the multi-Ub chain assembly of E3 ligase Arabidopsis thaliana RING Zinc Finger 1 (AtRZF1). To further investigate the function of other E4 Ub factors in osmotic stress, we isolated AtUAP2, an AtUAP1 homolog, which interacted with AtRZF1, using pull-down assay and bimolecular fluorescence complementation analysis. AtUAP2, a Ub-associated motif-containing protein, interacts with oligo-Ub5, -Ub6, and -Ub7 chains. The yeast functional complementation experiment revealed that AtUAP2 functions as an E4 Ub factor. In addition, AtUAP2 is localized in the cytoplasm, different from AtUAP1. The activity of AtUAP2 was relatively strongly induced in the leaf tissue of AtUAP2 promoter-ß-glucuronidase transgenic plants by abscisic acid, dehydration, and oxidative stress. atuap2 RNAi lines were more insensitive to osmotic stress condition than wild-type during the early growth of seedlings, whereas the AtUAP2-overexpressing line exhibited relatively more sensitive responses. Analyses of molecular and physiological experiments showed that AtUAP2 could negatively mediate the osmotic stress-induced signaling. Genetic studies showed that AtRZF1 mutation could suppress the dehydration-induced sensitive phenotype of the AtUAP2-overexpressing line, suggesting that AtRZF1 acts genetically downstream of AtUAP2 during osmotic stress. Taken together, our findings show that the AtRZF1-AtUAP2 complex may play important roles in the ubiquitination pathway, which controls the osmotic stress response in Arabidopsis.

Rhodamine 6G derivative for the selective copper detection and remediation using nanoporous diatomaceous earth-engineered functional receptor.

A rhodamine-derived receptor was synthesized and comprehensively characterized for structural confirmation. The receptor was able to distinguish the copper ions (Cu2+) from other competing cations. The yellow color of the receptor changed to pink upon adding Cu2+ ions, however, other competing cations ions were impotent towards any color variation. The UV-visible titration studies revealed the binding stoichiometry of a 1:1 ratio with a detection limit of 9.663 × 10-8 M. Additionally, a novel idea of the work resides in the use of diatom for the practical application, where the receptor has been tethered on nanoporous diatomaceous earth microparticles (P2D) to remove Cu2+ ions. The results confirmed that 50 mg receptor functionalized DE could adsorb 10 mL of 1 ppm Cu2+ ions from water. Furthermore, a proof-of-concept device that is inexpensive, simple to operate, and continuously removes Cu2+ ions from water has been developed. The efficiency of the device in Cu2+ ion removal could be realized through the naked eye by observing the color change of P2D particles, which has excellent potential for application in remote locations where water contamination is a significant issue.

Ratiometric colorimetric detection of fluoride ions using a schiff base sensor: enhancing selectivity and sensitivity for naked-eye analysis.

A Schiff base receptor with an active -NH group was designed and synthesized for the selective and sensitive colorimetric detection of inorganic fluoride (F-) ions in an aqueous medium. The sensitivity of the receptor for F- ions was enhanced by the influence of two electron-withdrawing -NO2 groups at ortho and para positions which result in a vivid color change. The receptor underwent a remarkable color change from light yellow to violet, enabling naked-eye detection of F- ions without the need for spectroscopic equipment. To ensure the structural integrity of the synthesized receptors, prominent spectroscopic techniques such as 1H NMR, FTIR, and GCMS analysis were used for characterization. With a limit of detection (LoD) of 0.0996 ppm, a 1 : 2 stoichiometric binding ratio was observed for receptor and F- ions. The binding mechanism confirmed the deprotonation of the -NH group followed by the formation of -HF2, resulting in an intramolecular charge transfer (ICT) transition, which correlates with UV-vis and 1H NMR titration results. In addition, the proposed binding mechanism of F- ion interaction with the receptor was theoretically validated using DFT and TDDFT calculations. Furthermore, as a real-life implementation of the receptor, quantification of the F- ions present in a commercially available mouthwash was demonstrated. To assess the sensitivity performance, a paper-based dip sensor and a solid substrate sensor by functionalizing the receptor on diatomaceous earth were demonstrated. Finally, sensors were built into smartphones that could recognize the red, green, and blue percentages (RGB%) where each parameter defines the intensity of the color, which could also be used as a supplement to the colorimetric investigations.

Recent Advances in Microfluidic Platform for Physical and Immunological Detection and Capture of Circulating Tumor Cells.

CTCs (circulating tumor cells) are well-known for their use in clinical trials for tumor diagnosis. Capturing and isolating these CTCs from whole blood samples has enormous benefits in cancer diagnosis and treatment. In general, various approaches are being used to separate malignant cells, including immunomagnets, macroscale filters, centrifuges, dielectrophoresis, and immunological approaches. These procedures, on the other hand, are time-consuming and necessitate multiple high-level operational protocols. In addition, considering their low efficiency and throughput, the processes of capturing and isolating CTCs face tremendous challenges. Meanwhile, recent advances in microfluidic devices promise unprecedented advantages for capturing and isolating CTCs with greater efficiency, sensitivity, selectivity and accuracy. In this regard, this review article focuses primarily on the various fabrication methodologies involved in microfluidic devices and techniques specifically used to capture and isolate CTCs using various physical and biological methods as well as their conceptual ideas, advantages and disadvantages.

BES1/BZR1 Homolog 3 cooperates with E3 ligase AtRZF1 to regulate osmotic stress and brassinosteroid responses in Arabidopsis.

Proline (Pro) metabolism plays important roles in protein synthesis, redox balance, and abiotic stress response. However, it is not known if cross-talk occurs between proline and brassinosteroid (BR) signaling pathways. Here, an Arabidopsis intergenic enhancer double mutant, namely proline content alterative 41 (pca41), was generated by inserting a T-DNA tag in the Arabidopsis thaliana ring zinc finger 1 (atrzf1 ) mutant background. pca41 had a T-DNA inserted at the site of the gene encoding BES1/BZR1 Homolog 3 (BEH3). pca41 has a drought-insensitive phenotype that is stronger than atrzf1 under osmotic stress, including high Pro accumulation and decreased amounts of reactive oxygen species. Analysis of physiological, genetic, and molecular networks revealed that negative regulation of BEH3 during abiotic stress was linked to the BR signaling pathway. Our data also suggest that AtRZF1, an E3 ubiquitin ligase, might control osmotic stress, abscisic acid, and BR responses in a BEH3-dependent manner. Under darkness, pca41 displays a long hypocotyl phenotype, which is similar to atrzf1 and beh3, suggesting that BEH3 acts in the same pathway as AtRZF1. Overexpression of BEH3 results in an osmotic stress-sensitive phenotype, which is reversed by exogenous BR application. Taken together, our results indicate that AtRZF1 and BEH3 may play important roles in the osmotic stress response via ubiquitination and BR signaling.

Paper-based colorimetric sensor for easy and simple detection of polygalacturonase activity aiming for diagnosis of Allium white rot disease.

Polygalacturonase (PG) activity in plants can serve as an important index for plant disease. However, the conventional method to detect PG activity is a complex process and requires a skilled technician and expensive analytical equipment. In this study, a paper-based colorimetric sensor was developed based on the principle of the ruthenium red (RR) dye method for easy and simple measurement of PG activity. The proposed paper-based sensor has a three-layer structure for detection of PG activity in samples. The sensor sensitivity was enhanced by optimizing the pH of the sodium acetate buffer used in polygalacturonic acid (PGA)-RR complex formation and the reaction temperature for PG and the PGA-RR complex. Further, for quantitative analysis of PG activity, Delta RGB analysis was conducted to detect color changes in the sensing window of the sensor. Results presented that the linear measurement range of the paper sensor was 0.02-0.1 unit with the limit of detection of 0.02 unit, which showed a similar detection range, but a lower detection limit, compared to the spectrophotometry. Furthermore, PG activity based on culture condition was measured using samples from Sclerotium cepivorum to verify the potential application of the developed paper-based sensor in the field. The measured activity showed no statistically significant difference from the values obtained from the spectrophotometry at 95% confidence level. Therefore, the paper-based colorimetric sensor can be used to predict plant diseases in Allium crops during the stage of pathogen invasion, potentially contributing to the improvement of crop production.

Highly sensitive enclosed multilayer paper-based microfluidic sensor for quantifying proline in plants.

Free proline, termed proline, is a biomarker used for diagnosing drought stress in plants. A previously developed proline-ninhydrin reaction-based paper sensor could quickly and easily detect proline, but it was limited by low sensitivity. In this study, we developed an enclosed multilayer paper-based microfluidic sensor with high sensitivity for the quantitative detection of proline in plants. The multilayer paper-based sensor was manufactured using simple wax printing and origami methods, and contained an internal mixing channel to allow good mixing of the proline with ninhydrin, increasing the proline-ninhydrin reactivity and providing accurate and sensitive proline detection. By preloading ninhydrin onto the sample loading area, uniform coloration of the sensing window was achieved, allowing quantitative analysis of various proline concentrations using a constant reaction time. Only the sensing window and sample loading area were exposed to limit sample evaporation and contamination from the external environment. The LOD of the fabricated sensor was 23 µM, which is approximately 29-fold lower than that of the previously proposed paper sensor (657 µM). Samples were extracted from A. thaliana plants subjected to drought stress for proline detection. The proline concentrations measured using the developed paper sensor and a spectrophotometric method were not statistically significant at a confidence level of 95%. Therefore, the developed sensor can be applied to measure proline concentrations precisely in the field with a low detection limit. The developed paper-based sensor can be used to detect the early stages of drought in plants and thus improve crop productivity.

Detection of proline using a novel paper-based analytical device for on-site diagnosis of drought stress in plants.

We developed and characterized a paper-based microfluidic sensor for the on-site diagnosis of drought stress in plants. Proline was used as a biomarker for analyzing drought stress, which was extracted by a colorimetric method using the proline-ninhydrin reaction. Paper was used as the main sensor material for the on-site detection of proline as it is easily transportable and cost-effective. The paper-based sensor was fabricated using wax-printing and origami methods, and the sensor was precoated with ninhydrin to allow for easy and convenient on-site use. Furthermore, a sample-to-ninhydrin ratio of 1:2 was found to confer optimal sensitivity to the drought diagnosis sensor. The concentration of proline in a sample was quantified by red-green-blue analysis to determine the change in green color intensity levels in response to distinct proline concentrations, which were detected by the sensor. The limit of detection of proline using the devised sensor was 657 µM, and the green color intensity level decreased with increasing proline concentration. In addition, the sensor was validated in an experimental drought stress model with Arabidopsis and subjected to drought stress for 21 days, and the amount of proline detected was 10 mM. The devised paper-based microfluidic sensor highlights the possibility of the on-site evaluation of drought stress in plants with potential to be utilized in various agricultural areas in the future.

A basic helix-loop-helix 104 (bHLH104) protein functions as a transcriptional repressor for glucose and abscisic acid signaling in Arabidopsis.

Transduction of glucose (Glc) signaling is critical for plant development, metabolism, and stress responses. However, identifying initial Glc sensing and response stimulating mechanisms in plants has been difficult due to dual functions of glucose as energy sources and signaling component. A basic Helix-Loop-Helix 104 (bHLH104) protein is a homolog of bHLH34 previously isolated from Arabidopsis that functions as a transcriptional activator of Glc and abscisic acid (ABA) responses. In this study, we characterized bHLH104 as a transcription factor that binds to the regulatory region of Arabidopsis Plasma membrane Glc-responsive Regulator (AtPGR) gene. The bHLH104 binds to 5'-AANA-3' element of the promoter region of AtPGR in vitro and represses beta-glucuronidase (GUS) activity in AtPGR promoter-GUS transgenic plants. Genetic approaches show that bHLH104 positively regulates Glc and abscisic acid (ABA) response. These results suggest that bHLH104 is involved in Glc- and ABA-mediated signaling pathway. Taken together, these findings provide evidence that bHLH104 is an important transcription regulator in plant-sensitivity to Glc and ABA signaling.

Optimization of the ninhydrin reaction and development of a multiwell plate-based high-throughput proline detection assay.

We developed a high-throughput technique for highly sensitive measurement of trace amounts of proline, an indicator of drought stress in plants, using an optimized proline-ninhydrin reaction. In order to do this, proline detection time was minimized by omitting phosphoric acid from the ninhydrin reagent. Chromophore extraction using toluene was also omitted, thus lowering the risks to environment and human health, and allowing the use of readily available polystyrene plates. Proline detection sensitivity was assessed based on the concentration of sulfosalicylic acid in the solution, which indicated that 1% sulfosalicylic acid yielded the best sensitivity and linearity. These findings were applied to a multiwell plate-based multiplex analysis using a dry oven for the simultaneous analysis of a large number of drought-stressed plant samples with trace amounts of proline. The results showed that proline could be effectively detected in plants grown in soil with water content under 5%, demonstrating its potential for diagnosing drought early. The proposed multiwell plate-based multiplex assay is expected to be useful in manifold agricultural applications.

Loss of Ribosomal Protein L24A (RPL24A) suppresses proline accumulation of Arabidopsis thaliana ring zinc finger 1 (atrzf1) mutant in response to osmotic stress.

Proline (Pro) metabolism in plants is involved in various cellular processes mediated during abiotic stress. However, the Pro-regulatory mechanisms are unclear. We used a suppressor mutation technique to isolate novel genes involved in the regulation of Pro metabolism in Arabidopsis. Using atrzf1 as a parental plant for T-DNA tagging mutagenesis, we identified a suppressor mutant, termed proline content alterative 21 (pca21), that displayed reduced Pro contents compared with the atrzf1 under osmotic stress conditions. Genomic Thermal Asymmetric Interlaced (TAIL)-PCR revealed pca21 harbored an inserted T-DNA in the region of At2g36620 that encodes Ribosomal Protein L24A. In general, the pca21 mutant partially suppressed the insensitivity of atrzf1 to osmotic stress and abscisic acid during seed germination and early seedling stage. Additionally, the pca21 mutant had increased MDA content and lower expression of several Pro biosynthesis-related genes than the atrzf1 mutant during drought condition. These results suggest that pca21 acts as partial suppressor of atrzf1 in the osmotic stress response through the Pro-mediated pathway.

PCA22 acts as a suppressor of atrzf1 to mediate proline accumulation in response to abiotic stress in Arabidopsis.

Proline metabolism is important for environmental responses, plant growth, and development. However, its precise roles in plant abiotic stress tolerance are not well understood. Mutants are valuable for the identification of new genes and for elucidating their roles in physiological mechanisms. We applied a suppressor mutation approach to identify novel genes involved in the regulation of proline metabolism in Arabidopsis. Using the atrzf1 (Arabidopsis thaliana ring zinc finger 1) mutant as a parental line for activation tagging mutagenesis, we selected several mutants with suppressed induction of proline accumulation under dehydration conditions. One of the selected mutants [proline content alterative 22 (pca22)] appeared to have reduced proline contents compared with the atrzf1 mutant under drought stress. Generally, pca22 mutant plants displayed suppressed atrzf1 insensitivity to dehydration and abscisic acid during early seedling growth. Additionally, the pca22 mutant exhibited shorter pollen tube length than wild-type (WT) and atrzf1 plants. Furthermore, PCA22-overexpressing plants were more sensitive to dehydration stress than the WT and RNAi lines. Green fluorescent protein-tagged PCA22 was localized to the cytoplasm of transgenic Arabidopsis cells. Collectively, these results suggest that pca22 acts as dominant suppressor mutant of atrzf1 in the abiotic stress response.

Arabidopsis Basic Helix-Loop-Helix 34 (bHLH34) Is Involved in Glucose Signaling through Binding to a GAGA Cis-Element.

The modulation of glucose (Glc) homeostasis and signaling is crucial for plant growth and development. Nevertheless, the molecular signaling mechanism by which a plant senses a cellular Glc level and coordinates the expression of Glc-responsive genes is still incompletely understood. Previous studies have shown that Arabidopsis thaliana plasma membrane Glc-responsive regulator (AtPGR) is a component of the Glc-responsive pathway. Here, we demonstrated that a transcription factor bHLH34 binds to 5'-GAGA-3' element of the promoter region of AtPGR in vitro, and activates beta-glucuronidase (GUS) activity upon Glc treatment in AtPGR promoter-GUS transgenic plants. Gain- and loss-of-function analyses suggested that the bHLH34 involved in the responses to not only Glc, but also abscisic acid (ABA) and salinity. These results suggest that bHLH34 functions as a transcription factor in the Glc-mediated stress responsive pathway as well as an activator of AtPGR transcription. Furthermore, genetic experiments revealed that in Glc response, the functions of bHLH34 are different from that of a bHLH104, a homolog of bHLH34. Collectively, our findings indicate that bHLH34 is a positive regulator of Glc, and may affect ABA or salinity response, whereas bHLH104 is a negative regulator and epistatic to bHLH34 in the Glc response.

Abscisic acid receptor PYRABACTIN RESISTANCE-LIKE 8, PYL8, is involved in glucose response and dark-induced leaf senescence in Arabidopsis.

Abscisic acid (ABA) receptors in plants are thought to be involved in various cellular processes mediated by signal transduction pathways. There are about 14 ABA receptors in Arabidopsis, but only a few have been studied. In this study, we investigated the effect of the disruption and overexpression of an ABA receptor gene, PYL8 (At5g53160) on plant responses to glucose (Glc) and dark-induced leaf senescence. Expression of PYL8 was strongly reduced by Glc treatment. Overexpression of PYL8 in Arabidopsis resulted in significantly reduced seed germination and cotyledon greening under high Glc conditions, while RNAi transgenic lines were more insensitive to Glc stress. Activities of two Glc-responsive genes, Arabidopsis thaliana Hexokinase 1 (AtHXK1) and ABA insensitive 5 (ABI5) were higher in PYL8-overexpressing plants than in the wild-type (WT) plants after Glc treatment, whereas the transcript levels of these genes in RNAi plants decreased. Furthermore, PYL8-overexpressing plants displayed increased yellowing, membrane ion leakage, and reduced chlorophyll content due to dark-induced senescence, and exhibited stronger expression of a group of senescence-inducible genes than did WT. The data show that PYL8 plays essential roles in responses to both Glc and dark-induced senescence in A. thaliana.

The CONSTANS-like 4 transcription factor, AtCOL4, positively regulates abiotic stress tolerance through an abscisic acid-dependent manner in Arabidopsis.

The precise roles of the B-box zinc finger family of transcription factors in plant stress are poorly understood. Functional analysis was performed on AtCOL4, an Arabidopsis thaliana L. CONSTANS-like 4 protein that is a putative novel transcription factor, and which contains a predicted transcriptional activation domain. Analyses of an AtCOL4 promoter-ß-glucuronidase (GUS) construct revealed substantial GUS activity in whole seedlings. The expression of AtCOL4 was strongly induced by abscisic acid (ABA), salt, and osmotic stress. Mutation in atcol4 resulted in increased sensitivity to ABA and salt stress during seed germination and the cotyledon greening process. In contrast, AtCOL4-overexpressing plants were less sensitive to ABA and salt stress compared to the wild type. Interestingly, in the presence of ABA or salt stress, the transcript levels of other ABA biosynthesis and stress-related genes were enhanced induction in AtCOL4-overexpressing and WT plants, rather than in the atcol4 mutant. Thus, AtCOL4 is involved in ABA and salt stress response through the ABA-dependent signaling pathway. Taken together, these findings provide compelling evidence that AtCOL4 is an important regulator for plant tolerance to abiotic stress.

Monolimb paralysis after laparoscopic appendectomy due to conversion disorder.

Limb paralysis can develop for various reasons. We found a 13-year-old patient who became paralyzed in her lower extremities after laparoscopic appendectomy. Some tests, including electrodiagnostic studies and magnetic resonance imaging, were performed to evaluate the cause of lower limb paralysis. None of the tests yielded definite abnormal findings. We subsequently decided to explore the possibility of psychological problems. The patient was treated with simultaneous rehabilitation and psychological counseling. Paralysis of the patient's lower extremity improved gradually and the patient returned to normal life. Our findings indicate that psychological problems can be related to limb paralysis without organ damage in patients who have undergone laparoscopic surgical procedures.

Highly ordered and vertically oriented TiO2/Al2O3 nanotube electrodes for application in dye-sensitized solar cells.

The surface of long TiO2 nanotube (NT) electrodes in dye-sensitized solar cells (DSSCs) was modified without post-annealing by using atomic layer deposition (ALD) for the enhancement of photovoltage. Vertically oriented TiO2 NT electrodes with highly ordered and crack-free surface structures over large areas were prepared by a two-step anodization method. The prepared TiO2 NTs had a pore size of 80 nm, and a length of 23 µm. Onto these TiO2 NTs, an Al2O3 shell of a precisely controlled thickness was deposited by ALD. The conformally coated shell layer was confirmed by high-resolution transmission electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. The open-circuit voltage (V(oc)) of the DSSCs was gradually enhanced as the thickness of the Al2O3 shell of the TiO2/Al2O3 NT electrodes was increased, which resulted from the enhanced electron lifetime. The enhanced electron lifetime caused by the energy barrier effect of the shell layer was measured quantitatively by the open-circuit voltage decay technique. As a result, 1- and 2-cycle-coated samples showed enhanced conversion efficiencies compared to the bare sample.

AtSKIP functions as a mediator between cytokinin and light signaling pathway in Arabidopsis thaliana.

KEY MESSAGE: AtSKIP participated in cytokinin-regulated leaf initiation. Putative phosphorylated AtSKIP (AtSKIP (DD) ) displayed the opposite function in the leaf development from AtSKIP transgenic seedlings. ABSTRACT: AtSKIP, as a multiple protein, is involved in many physiological processes, such as flowering, cell cycle regulator, photomorphogenesis and stress tolerance. However, the mechanism of AtSKIP in these processes is unclear. Here, we identify one gene, AtSKIP, which is associated with cytokinin-regulated leaf growth process in Arabidopsis. The expression of AtSKIP was regulated by cytokinin. Leaf development in AtSKIP overproduced seedlings was independent of light, but promoted by cytokinin, and phosphorylation of AtSKIP (AtSKIP(DD)) partially interfered with AtSKIP function as a positive regulator in cytokinin signaling, indicative of true leaf formation, and the defects of AtSKIP(DD) in the true leaf formation could be recovered to some extent by the addition of cytokinin. Moreover, different cytokinin-responsive gene Authentic Response Regulator 7 (ARR7) promoter-GUS activity further proved that expression of AtSKIP or AtSKIP(DD) altered endogenous cytokinin signaling in plants. Together, these data indicate that AtSKIP participates in cytokinin-regulated promotion of leaf growth in photomorphogenesis, and that phosphorylation interferes with AtSKIP normal function.

Rapid detection of norovirus from fresh lettuce using immunomagnetic separation and a quantum dots assay.

Current molecular methods that include PCR have been used to detect norovirus in many food samples. However, the protocols require removing PCR inhibitors and incorporate time-consuming concentration steps to separate virus from analyte for rapid and sensitive detection of norovirus. We developed an immunomagnetic separation (IMS) and a quantum dots (QDs) assay to detect norovirus eluted from fresh lettuce with Tris buffer containing 1% beef extract (pH 9.5). IMS facilitated viral precipitation with a 10-min incubation, whereas virus concentration using polyethylene glycol (PEG) requires more than 3 h and an additional high-speed centrifugation step to precipitate virus before reverse transcription PCR (RT-PCR) analysis. The fluorescence intensity of QDs was detected qualitatively on norovirus dilutions of 10(-1) to 10(-3) in a stool suspension (100 RT-PCR units/ml). The results suggest that a fluorescence assay based on IMS and QDs is valid for detecting norovirus qualitatively according to fluorescent signal intensity within the same virus detection limit produced by IMS-RT-PCR and PEG-RT-PCR.