1,532 research outputs found
μν λ΄ λ³μμ± λμ₯κ· O157:H7μ κ²μΆμ μν μνλ¨Έ κΈ°λ°μ μ΄μ€κΈ°λ₯λ§μ»€ κ°λ° λ° κΈ λλ Έμ μ μμ§ κΈ°λ° λΉμ μ΄μΈμ΄ κ°λ°
νμλ
Όλ¬Έ(μμ¬) -- μμΈλνκ΅λνμ : λμ
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κ³Όνλν λμλͺ
곡νλΆ, 2023. 2. μ΅μμ§.In this study, we developed a colorimetric assay with bi-functional gold nanoparticle (AuNP) based on aptamer for sensitive detection of Escherichia coli O157:H7 using the aggregation of AuNP linked with a complementary DNA aptamer specific to E. coli O157:H7 aptamer. AuNP was used as a colorimetric linker and probe, respectively, and E. coli O157:H7 aptamer and its complementary DNA sequences were modified on each AuNP surface. AuNP labeled with E. coli O157:H7 aptamer was used as a bi-functional linker (BL) in a colorimetric competitive assay. Colorimetric assay with BL based on aptamer detected target bacteria by sequential competitive binding between colorimetric probes, which are AuNP having complementary sequences of E. coli O157:H7 (AA, Aggregation Assistant) and E. coli O157:H7 aptamer. In addition, under optimized conditions by main testing parameters, the assay exhibited a detection range of 101 to 106 CFU/400 Β΅L and a detection limit of 57 Β± 0.5 CFU/400 Β΅L. In addition, the developed colorimetric assay with BL based on aptamer was excellently evaluated as an on/off detection system in coconut water, a real matrix. Thus, the proposed colorimetric competitive assay with BL based on aptamer can be a proper on-site detection method of foodborne pathogens. In addition, this study provides the basis for research into developing different colorimetric assay with aptamer for pathogen analysis in real matrices.
This colorimetric assay with BL based on aptamer functions by driving the system between two competitive interaction dynamics: A) affinity between the aptamer sequence and the target, and B) affinity between the aptamer and the its complementary DNA aptamer.μ΄ μ°κ΅¬μμ μ°λ¦¬λ E. coli O157μ νΉμ΄μ μΈ μνλ¨Έμ μ보μ DNA μνλ¨Έκ° κ²°ν©λ AuNPμ μμ§μ κΈ°μ΄νμ¬ E. coli O157:H7μ νμ₯μμ μ μνλ©° λ―Όκ°νκ² κ²μΆν μ μλ, μνλ¨Έκ° κ²°ν©λ μ΄μ€ κΈ°λ₯λ§μ»€ AuNPλ₯Ό μ΄μ©ν λΉμ κ²μΆλ²μ κ°λ°νμλ€. μ΄ μμ€ν
μμ AuNPλ μ΄μ€κΈ°λ₯λ§μ»€ λ° μμ§λ³΄μ‘° νλ‘λΈλ‘ μ¬μ©λμμΌλ©°, κ° AuNP νλ©΄μ E. coli O157:H7 λμ μνλ¨Έμ μ보μ μΈ DNA μμ΄μ μνλ¨Έλ‘ κ²°ν©λμμΌλ©°, μ΄λ κ°κ° μ΄μ€κΈ°λ₯λ§μ»€ AuNP (BL)μ μμ§λ³΄μ‘° νλ‘λΈ AuNP (AA)λ‘ λͺ
λͺ
νμλ€. BLμ λμκ· μ΄ μ‘΄μ¬νμ§ μμ λμλ μ보μ μΈ μμ΄μ μν΄ AAμ κ²°ν©νμμΌλ©°, μμ κ· νμ μν΄ νΉμ μμ(REVC, 120 β 220 ΞΌL)μμ μμ§ λ° μΉ¨μ μ΄ μΌμ΄λ¬λ€. νμ§λ§, λμκ· μ΄ ν¬μ
λμμ λμλ κ²½μμ κ²°ν© μ°μ μμμ μν΄ μ보μ μμ΄μ AAκ° μλλΌ λμκ· μΈ E. coli O157:H7κ³Ό κ²°ν©νκ² λλ€. μ΄λ κΈ°μ‘΄μ μμ κ· νμμμ μ°¨μ΄λ₯Ό μΌμΌν€κ² λκ³ λμ‘°κ΅°κ³Ό μ μ¬ν μμ§ λ° μΉ¨μ μ΄ μΌμ΄λκΈ° μν΄μλ κΈ°μ‘΄λ³΄λ€ λ λ§μ μμ BLμ΄ λ°μμ μ°Έμ¬νμ¬μΌ νλ€. μ΄λ₯Ό ν΅ν΄ λμ‘°κ΅°κ³Ό λμκ· κ°μλ REVC μμμ λ³νκ° λ°μνκ² λλ©°, μ΄λ₯Ό ν΅ν΄ λμκ· μ μ 무λ₯Ό νμΈν μ μμλ€. κ²μΆμ κ°μ₯ λ―Όκ°νλ©° ꡬλΆλλ BL μμμΈ 100, 120, 140 ΞΌLμμ μ§νλμμΌλ©°, μ΅μ νλ 쑰건μμ 101 ~ 106 CFU/400 ΞΌLμ κ²μΆ λ²μμ 57 Β± 0.5 CFU/400 Lμ κ²μΆ νκ³λ₯Ό λνλλ€. λν μνλ¨Έ κΈ°λ°μ BLμ μ΄μ©ν λΉμλΆμλ²μ μ€μ 맀νΈλ¦μ€μΈ μ½μ½λμν°μμλ on/off κ°μ§ μμ€ν
μΌλ‘ λ§€μ° μ°μνκ² νκ°λμλ€. λ°λΌμ μ μλ μνλ¨Έ κΈ°λ°μ BLμ μ΄μ©ν λΉμλΆμλ²μ μμ€λ
μ μΌμΌν€λ λ³μ체λ₯Ό νμ₯μμ κ²μΆνλ λ° μ ν©ν λ°©λ²μ΄ λ μ μμ κ²μΌλ‘ κΈ°λλλ€. λν, λ³Έ μ°κ΅¬λ₯Ό ν΅ν΄ μ€μ 맀νΈλ¦μ€μμ λ³μκ· λΆμμ μν μ±νλ¨Έ κΈ°λ° λΉμ λΆμ κ°λ°μ λν ν₯ν μ°κ΅¬μ κΈ°λ°μ μ 곡ν μ μμλ€. μ΄ μνλ¨Έ κΈ°λ° λΉμ λΆμλ²μ A) μνλ¨Έ μμ΄κ³Ό νμ μ¬μ΄μ μΉνμ±, B) μνλ¨Έμ κ·Έ μ보μ μΈ DNA μνλ¨Έ μ¬μ΄μ μΉνλ ₯μ΄λΌλ λ κ°μ§ κ²½μμ μΈ μνΈ μμ© μνμ μν΄ κ΅¬λλμλ€.β
. INTRODUCTION οΌ
β
‘. MATERIALS AND METHODS 5
2.1. Materials 5
2.2. Instrumentation 5
2.3. Culturing of Bacteria 6
2.4. Preparation of gold nanoparticles (AuNP) 6
2.5. Modification of AuNP with aptamer 7
2.6. Optimization of NaCl concentrations 8
2.7. Detection of E. coli O157:H7 in samples 8
2.8. Verification of the selectivity of the detection method 9
2.9. Statistical analysis 10
β
’. RESULTS AND DISCUSSION 11
3.1. Overall detection procedures 11
3.2. Optimization of NaCl concentrations 17
3.3. Selectivity of the colorimetric assay 25
3.4. The range of REVC 27
3.5. Detection of E. coli O157:H7 in HEPES buffer 29
3.6. Detection of E. coli O157:H7 in coconut water 34
CONCLUSION 39
REFERENCES 41
κ΅λ¬Έμ΄λ‘ 45μ
Short term outcomes of topiramate monotherapy as a first-line treatment in newly diagnosed West syndrome
PurposeTo investigate the efficacy of topiramate monotherapy in West syndrome prospectively.MethodsThe study population included 28 patients (15 male and 13 female children aged 2 to 18 months) diagnosed with West syndrome. After a 2-week baseline period for documentation of the frequency of spasms, topiramate was initiated at 2 mg/kg/day. The dose was increased by 2 mg/kg every week to a maximum of 12 mg/kg/day. Clinical assessment was based on the parents' report and a neurological examination every 2 weeks for the first 2 months of treatment. The baseline electroencephalograms (EEGs) were compared with the post-treatment EEGs at 2 weeks and 1 month.ResultsWest syndrome was considered to be cryptogenic in 7 of the 28 patients and symptomatic in 21 patients. After treatment, 11 patients (39%) became spasm-free, 6 (21%) had more than 50% spasmsreduction, 3 (11%) showed less than 50% reduction, and 8 (29%) did not respond. The effective daily dose for achieving more than 50% reduction in spasm frequency, including becoming spasm-free, was found to be 5.8Β±1.1 mg/kg/day. Nine patients (32%) showed complete disappearance of spasms and hypsarrhythmia, and 11 (39%) showed improved EEG results. Despite adverse events (4 instances of irritability, 3 of drowsiness, and 1 of decreased feeding), no patients discontinued the medication.ConclusionTopiramate monotherapy seems to be effective and well tolerated as a first line therapy for West syndrome and is not associated with serious adverse effects
Characterizations of realized metal-insulator-silicon-insulator-metal waveguides and nanochannel fabrication via insulator removal
We investigate experimentally metal-insulator-silicon-insulator-metal (MISIM) waveguides that are fabricated by using fully standard CMOS technology. They are hybrid plasmonic waveguides, and they have a feature that their insulator is replaceable with functional material. We explain a fabrication process for them and discuss fabrication results based on 8-inch silicon-on-insulator wafers. We measured the propagation characteristics of the MISIM waveguides that were actually fabricated to be connected to Si photonic waveguides through symmetric and asymmetric couplers. When incident light from an optical source has transverse electric (TE) polarization and its wavelength is 1318 or 1554 nm, their propagation losses are between 0.2 and 0.3 dB/mu m. Excess losses due to the symmetric couplers are around 0.5 dB, which are smaller than those due to the asymmetric couplers. Additional measurement results indicate that the MISIM waveguide supports a TE-polarized hybrid plasmonic mode. Finally, we explain a process of removing the insulator without affecting the remaining MISIM structure to fabricate similar to 30-nm-wide nanochannels which may be filled with functional material.open8
Characterization of the Lytic Bacteriophage phiEaP-8 Effective against Both Erwinia amylovora and Erwinia pyrifoliae Causing Severe Diseases in Apple and Pear
Bacteriophages, bacteria-infecting viruses, have been recently reconsidered as a biological control tool for preventing bacterial pathogens. Erwinia amylovora and E. pyrifoliae cause fire blight and black shoot blight disease in apple and pear, respectively. In this study, the bacteriophage phiEaP-8 was isolated from apple orchard soil and could efficiently and specifically kill both E amylovora and E. pyrifoliae. This bacteriophage belongs to the Podoviridae family. Whole genome analysis revealed that phiEaP-8 carries a 75,929 bp genomic DNA with 78 coding sequences and 5 tRNA genes. Genome comparison showed that phiEaP-8 has only 85% identity to known bacteriophages at the DNA level. PhiEaP-8 retained lytic activity up to 50 degrees C, within a pH range from 5 to 10, and under 365 nm UV light. Based on these characteristics, the bacteriophage phiEaP-8 is novel and carries potential to control both E. amylovora and E. pyrifoliae in apple and pear
Comparative analysis of FBS containing media and serum free chemically defined media, CellCor for adipose derived stem cells production
Background:
As a result of the aging society, the average OECD life expectancy has grown to about 80 years, yet the average health life still remains at only 65 years, leaving more than 15 years of life in an uncertain health state. Regenerative medicine is a new concept of medicine that combines cells and biomaterials to restore the functions of aged or damaged tissues or organs. It is also a good treatment for chronic diseases and incurable diseases, receiving attention as a new paradigm for treating diseases.
Problems:
As the market for regenerative medicine grows, mass production of consistent quality cells is required. Media is the most important thing in mass production of consistent quality cells. However, the fetal bovine serum (FBS) containing media that is currently wide used has many problems, such as unidentified viral infection, immunogenicity, lot variations, unstable supply, and ethical issues. To solve these problems and make rapid progress in regenerative medicine, a high-performance serum free chemically defined media (CDM) is needed.
Solution:
CellCor is a serum free CDM that provides excellent performance, safety, economy and consistency in stem cell production. CellCor allows higher-speed cell production rate than current FBS containing culture media (Figure 1). Compared to the FBS containing media, CellCor is able to maintain stem cell markers, higher population homogeneity, genetic stability, and excellent differentiation potency even at later passage.
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