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1.
Nat Commun ; 15(1): 3378, 2024 Apr 20.
Article in English | MEDLINE | ID: mdl-38643147

ABSTRACT

Reentrant superconductivity is an uncommon phenomenon in which the destructive effects of magnetic field on superconductivity are mitigated, allowing a zero-resistance state to survive under conditions that would otherwise destroy it. Typically, the reentrant superconducting region derives from a zero-field parent superconducting phase. Here, we show that in UTe2 crystals extreme applied magnetic fields give rise to an unprecedented high-field superconductor that lacks a zero-field antecedent. This high-field orphan superconductivity exists at angles offset between 29o and 42o from the crystallographic b to c axes with applied fields between 37 T and 52 T. The stability of field-induced orphan superconductivity presented in this work defies both empirical precedent and theoretical explanation and demonstrates that high-field superconductivity can exist in an otherwise non-superconducting material.

2.
Article in English | MEDLINE | ID: mdl-37559223

ABSTRACT

Background: This study aimed to investigate differences in intrinsic prefrontal functional connectivity according to the presence of cognitive impairment in patients with end-stage renal disease (ESRD) using functional near-infrared spectroscopy (fNIRS). Methods: We prospectively enrolled 37 patients with ESRD who had been undergoing hemodialysis for more than 6 months and had no history of neurological or psychiatric disorders. All patients with ESRD underwent the Korean version of the Montreal Cognitive Assessment (MoCA-K) to assess cognitive function. The NIRSIT Lite device (OBELAB Inc.) was used to acquire fNIRS data, and the NIRSIT Lite Analysis Tool program was used to process the data and generate a functional connectivity matrix. We obtained functional connectivity measures by applying graph theory to the connectivity matrix using the BRAPH (brain analysis using graph theory) program. Results: Of the 37 patients with ESRD, 23 had cognitive impairment, whereas 14 patients showed no cognitive impairment. Intrinsic prefrontal functional connectivity was significantly different between groups. Network measures of strength, global efficiency, and mean clustering coefficient were lower in ESRD patients with cognitive impairment than in those without cognitive impairment (4.458 vs. 5.129, p = 0.02; 0.397 vs. 0.437, p = 0.03; and 0.316 vs. 0.421, p = 0.003; respectively). There were no significant correlations between MoCA-K scores and clinical characteristics. Conclusion: We demonstrated a significant association between cognitive function and intrinsic prefrontal functional connectivity in patients with ESRD. ESRD patients with cognitive impairment have reduced connectivity and segregation in the prefrontal brain network compared to those without cognitive impairment.

3.
Microb Cell Fact ; 20(1): 129, 2021 Jul 08.
Article in English | MEDLINE | ID: mdl-34238305

ABSTRACT

BACKGROUND: Xylanase-containing enzyme cocktails are used on an industrial scale to convert xylan into value-added products, as they hydrolyse the ß-1,4-glycosidic linkages between xylopyranosyl residues. In the present study, we focused on xynS1, the glycoside hydrolase (GH) 11 xylanase gene derived from the Streptomyces sp. strain J103, which can mediate XynS1 protein synthesis and lignocellulosic material hydrolysis. RESULTS: xynS1 has an open reading frame with 693 base pairs that encodes a protein with 230 amino acids. The predicted molecular weight and isoelectric point of the protein were 24.47 kDa and 7.92, respectively. The gene was cloned into the pET-11a expression vector and expressed in Escherichia coli BL21(DE3). Recombinant XynS1 (rXynS1) was purified via His-tag affinity column chromatography. rXynS1 exhibited optimal activity at a pH of 5.0 and temperature of 55 °C. Thermal stability was in the temperature range of 50-55 °C. The estimated Km and Vmax values were 51.4 mg/mL and 898.2 U/mg, respectively. One millimolar of Mn2+ and Na+ ions stimulated the activity of rXynS1 by up to 209% and 122.4%, respectively, and 1 mM Co2+ and Ni2+ acted as inhibitors of the enzyme. The mixture of rXynS1, originates from Streptomyces sp. strain J103 and acetyl xylan esterase (AXE), originating from the marine bacterium Ochrovirga pacifica, enhanced the xylan degradation by 2.27-fold, compared to the activity of rXynS1 alone when Mn2+ was used in the reaction mixture; this reflected the ability of both enzymes to hydrolyse the xylan structure. The use of an enzyme cocktail of rXynS1, AXE, and commercial cellulase (Celluclast® 1.5 L) for the hydrolysis of lignocellulosic biomass was more effective than that of commercial cellulase alone, thereby increasing the relative activity 2.3 fold. CONCLUSION: The supplementation of rXynS1 with AXE enhanced the xylan degradation process via the de-esterification of acetyl groups in the xylan structure. Synergetic action of rXynS1 with commercial cellulase improved the hydrolysis of pre-treated lignocellulosic biomass; thus, rXynS1 could potentially be used in several industrial applications.


Subject(s)
Acetylesterase/metabolism , Endo-1,4-beta Xylanases/metabolism , Lignin/metabolism , Streptomyces/enzymology , Xylans/metabolism , Biomass , Cellulase/metabolism , Cloning, Molecular , Escherichia coli/genetics , Hydrogen-Ion Concentration , Hydrolysis , Metals/pharmacology , Recombinant Proteins/metabolism , Temperature
4.
Nat Commun ; 12(1): 3311, 2021 Jun 03.
Article in English | MEDLINE | ID: mdl-34083533

ABSTRACT

In systems near phase transitions, macroscopic properties often follow algebraic scaling laws, determined by the dimensionality and the underlying symmetries of the system. The emergence of such universal scaling implies that microscopic details are irrelevant. Here, we locally investigate the scaling properties of the metal-insulator transition at the LaAlO3/SrTiO3 interface. We show that, by changing the dimensionality and the symmetries of the electronic system, coupling between structural and electronic properties prevents the universal behavior near the transition. By imaging the current flow in the system, we reveal that structural domain boundaries modify the filamentary flow close to the transition point, preventing a fractal with the expected universal dimension from forming.

5.
Nano Lett ; 21(10): 4454-4460, 2021 May 26.
Article in English | MEDLINE | ID: mdl-33989008

ABSTRACT

A new synthetic approach has recently been developed for the fabrication of freestanding crystalline perovskite oxide nanomembranes, which involves the epitaxial growth of a water-soluble sacrificial layer. By utilizing an ultrathin capping layer of SrTiO3, here we show that this sacrificial layer, as grown by pulsed laser deposition, can be stabilized in air and therefore be used as transferrable templates for ex situ epitaxial growth using other techniques. We find that the stability of these templates depends on the thickness of the capping layer. On these templates, freestanding superconducting SrTiO3 membranes were synthesized ex situ using molecular beam epitaxy, enabled by the lower growth temperature which preserves the sacrificial layer. This study paves the way for the synthesis of an expanded selection of freestanding oxide membranes and heterostructures with a wide variety of ex situ growth techniques.

6.
J Microbiol Biotechnol ; 31(3): 408-418, 2021 Mar 28.
Article in English | MEDLINE | ID: mdl-33397833

ABSTRACT

The diversity and plant growth-promoting ability of fungal endophytes that are associated with five halophytic plant species (Phragmites australis, Suaeda australis, Limonium tetragonum, Suaeda glauca Bunge, and Suaeda maritima) growing in the Buan salt marsh on the west coast of South Korea have been explored. About 188 fungal strains were isolated from these plant samples' roots and were then studied with the use of the internal transcribed spacer (ITS) region (ITS1-5.8S-ITS2). The endophytic fungal strains belonged to 33 genera. Alternaria (18%) and Fusarium (12.8%), of the classes Dothideomycetes and Sordariomycetes, were most rampant in the coastal salt marsh plants. There was a higher diversity in fungal endophytes that are isolated from S. glauca Bunge than in isolates from other coastal salt marsh plants. Plant growth-promoting experiments with the use of Waito-C rice seedlings show that some of the fungal strains could encourage a more efficient growth than others. Furthermore, gibberellins (GAs) GA1, GA3, and GA9 were seen in the Sa-1-4-3 isolate (Acrostalagmus luteoalbus) culture filtrate with a gas chromatography/mass spectrometry.


Subject(s)
Alternaria , Endophytes/classification , Fusarium , Salt-Tolerant Plants/microbiology , Wetlands , Alternaria/classification , Alternaria/isolation & purification , Ascomycota/metabolism , Biodiversity , DNA, Fungal/genetics , Endophytes/isolation & purification , Fusarium/classification , Fusarium/isolation & purification , Gibberellins/metabolism , Oryza/microbiology , Phylogeny , Plant Growth Regulators , Plant Roots/microbiology , Polymerase Chain Reaction , Republic of Korea , Salt-Tolerant Plants/growth & development , Sequence Analysis, DNA , Symbiosis
7.
Mar Drugs ; 20(1)2021 Dec 21.
Article in English | MEDLINE | ID: mdl-35049857

ABSTRACT

We recently identified a ß-agarase, Gaa16B, in the marine bacterium Gilvimarinus agarilyticus JEA5. Gaa16B, belonging to the glycoside hydrolase 16 family of ß-agarases, shows less than 70.9% amino acid similarity with previously characterized agarases. Recombinant Gaa16B lacking the carbohydrate-binding region (rGaa16Bc) was overexpressed in Escherichia coli and purified. Activity assays revealed the optimal temperature and pH of rGaa16Bc to be 55 ∘C and pH 6-7, respectively, and the protein was highly stable at 55 ∘C for 90 min. Additionally, rGaa16Bc activity was strongly enhanced (2.3-fold) in the presence of 2.5 mM MnCl2. The Km and Vmax of rGaa16Bc for agarose were 6.4 mg/mL and 953 U/mg, respectively. Thin-layer chromatography analysis revealed that rGaa16Bc can hydrolyze agarose into neoagarotetraose and neoagarobiose. Partial hydrolysis products (PHPs) of rGaa16Bc had an average molecular weight of 88-102 kDa and exhibited > 60% hyaluronidase inhibition activity at a concentration of 1 mg/mL, whereas the completely hydrolyzed product (CHP) showed no hyaluronidase at the same concentration. The biochemical properties of Gaa16B suggest that it could be useful for producing functional neoagaro-oligosaccharides. Additionally, the PHP of rGaa16Bc may be useful in promoting its utilization, which is limited due to the gel strength of agar.


Subject(s)
Gammaproteobacteria , Glycoside Hydrolases/pharmacology , Animals , Aquatic Organisms , Cosmeceuticals , Glycoside Hydrolases/chemistry , Hydrogen-Ion Concentration , Hydrolysis
8.
Nano Lett ; 20(8): 5735-5740, 2020 Aug 12.
Article in English | MEDLINE | ID: mdl-32574061

ABSTRACT

A variety of nickel oxide compounds have long been studied for their manifestation of various correlated electron phenomena. Recently, superconductivity was observed in nanoscale infinite layer nickelate thin films of Nd0.8Sr0.2NiO2, epitaxially stabilized on SrTiO3 substrates via topotactic reduction from the perovskite precursor phase. Here, we present the synthesis and properties of PrNiO2 thin films on SrTiO3. Upon doping in Pr0.8Sr0.2NiO2, we observe superconductivity with a transition temperature of 7-12 K and robust critical current density at 2 K of 334 kA/cm2. These findings indicate that superconductivity in the infinite layer nickelates is relatively insensitive to the details of the rare earth 4f configuration. Furthermore, they motivate the exploration of a broader family of compounds based on two-dimensional NiO2 planes, which will enable systematic investigation of the superconducting and normal state properties and their underlying mechanisms.

9.
Technol Health Care ; 28(S1): 499-507, 2020.
Article in English | MEDLINE | ID: mdl-32364182

ABSTRACT

BACKGROUND: It is important to quantitatively assess tremor for accurate diagnosis and evaluation of the response to interventions in patients with essential tremor (ET). OBJECTIVE: The purpose of this study was to investigate the relationship between quantitative measures of postural tremor and clinical rating scale in patients with ET. METHODS: 18 ET patients performed a postural tremor task that required them to hold their arms outstretched parallel to the floor while wearing a gyro sensor based measurement system. The time domain variables were derived from the sensor signals. Additionally, the frequency domain variables were derived from the power spectrum of the angular velocity signal. Spearman correlation analysis was employed in the relationship between the variables and clinical score. RESULTS: The RMS angular velocity of roll and yaw directions at the hand joint were strongly correlated with the clinical rating scale (r= 0.7, p< 0.01). Similarly, the peak power of roll and yaw directions at the hand joint were moderately correlated with the clinical rating scale (r= 0.61 and r= 0.67, p< 0.01). In contrast, no significant correlation coefficients were observed in the peak frequency (p> 0.05). CONCLUSION: These results indicate that hand tremor of roll and yaw directions are more associated with assessment of severity of ET compared to other joints. This study suggests that quantitative measurements of postural tremor should be considered as tremor directionality as well as attachment location.


Subject(s)
Essential Tremor/diagnosis , Essential Tremor/physiopathology , Tremor/physiopathology , Upper Extremity/physiopathology , Wearable Electronic Devices , Aged , Female , Humans , Male , Middle Aged , Reproducibility of Results
10.
J Microbiol Biotechnol ; 30(2): 296-305, 2020 Feb 28.
Article in English | MEDLINE | ID: mdl-32120462

ABSTRACT

Tricholoma matsutake is an ectomycorrhizal fungus, related with the host of Pinus densiflora. Most of studies on T. matsutake have focused on mycelial growth, genes and genomics, phylogenetics, symbiosis, and immune activity of this strain. T. matsutake is known for its unique fragrance in Eastern Asia. The most major component of its scent is (R)-(-)-1-octen-3-ol and is biosynthesized from the substrate linoleic acid by the sequential reaction of lipoxygenase and peroxide lyase. Here, we report for the first time the biosynthesis of (R)-(-)- 1-octen-3-ol of T. matsutake using the yeast Saccharomyces cerevisiae as a host. In this study, cDNA genes correlated with these reactions were cloned from T. matsutake, and expression studies of theses genes were carried out in the yeast Saccharomyces cerevisiae. The product of these genes expression study was carried out with Western blotting. The biosynthesis of (R)-(-)- 1-octen-3-ol of T. matsutake in recombinant Saccharomyces cerevisiae was subsequently identified with GC-MS chromatography analysis. The biosynthesis of (R)-(-)-1-octen-3-ol with S. cerevisiae represents a significant step forward.


Subject(s)
Aldehyde-Lyases/genetics , Cytochrome P-450 Enzyme System/genetics , Gene Expression , Lipoxygenase/genetics , Octanols/metabolism , Saccharomyces cerevisiae/metabolism , Tricholoma/enzymology , Tricholoma/genetics , Cloning, Molecular , Fermentation , Isoenzymes , Recombinant Proteins , Temperature , Transformation, Genetic
11.
Microb Cell Fact ; 18(1): 122, 2019 Jul 08.
Article in English | MEDLINE | ID: mdl-31286972

ABSTRACT

BACKGROUND: Acetyl xylan esterase plays an important role in the complete enzymatic hydrolysis of lignocellulosic materials. It hydrolyzes the ester linkages of acetic acid in xylan and supports and enhances the activity of xylanase. This study was conducted to identify and overexpress the acetyl xylan esterase (AXE) gene revealed by the genomic sequencing of the marine bacterium Ochrovirga pacifica. RESULTS: The AXE gene has an 864-bp open reading frame that encodes 287 aa and consists of an AXE domain from aa 60 to 274. Gene was cloned to pET-16b vector and expressed the recombinant AXE (rAXE) in Escherichia coli BL21 (DE3). The predicted molecular mass was 31.75 kDa. The maximum specific activity (40.08 U/mg) was recorded at the optimal temperature and pH which were 50 °C and pH 8.0, respectively. The thermal stability assay showed that AXE maintains its residual activity almost constantly throughout and after incubation at 45 °C for 120 min. The synergism of AXE with xylanase on beechwood xylan, increased the relative activity 1.41-fold. CONCLUSION: Resulted higher relative activity of rAXE with commercially available xylanase on beechwood xylan showed its potential for the use of rAXE in industrial purposes as a de-esterification enzyme to hydrolyze xylan and hemicellulose-like complex substrates.


Subject(s)
Acetylesterase/metabolism , Bacterial Proteins/metabolism , Endo-1,4-beta Xylanases/metabolism , Fagus/chemistry , Flavobacteriaceae/enzymology , Xylans/metabolism , Acetylesterase/genetics , Amino Acid Sequence , Bacterial Proteins/genetics , Base Sequence , Enzyme Stability , Flavobacteriaceae/genetics , Hydrogen-Ion Concentration , Hydrolysis , Industrial Microbiology , Open Reading Frames , Seawater/microbiology , Substrate Specificity , Temperature
12.
Microb Cell Fact ; 18(1): 79, 2019 May 03.
Article in English | MEDLINE | ID: mdl-31053078

ABSTRACT

BACKGROUND: Styrene is a large-volume commodity petrochemical, which has been used in a wide range of polymer industry as the main building block for the construction of various functional polymers. Despite many efforts to produce styrene in microbial hosts, the production titers are still low and are not enough to meet the commercial production of styrene. RESULTS: Previously, we developed a high L-phenylalanine producer (E. coli YHP05), and it was used as a main host for de novo synthesis of styrene. First, we introduced the co-expression system of phenylalanine-ammonia lyase (PAL) and ferulic acid decarboxylase (FDC) genes for the synthesis of styrene from L-phenylalanine. Then, to minimize cell toxicity and enhance the recovery of styrene, in situ product recovery (ISPR) with n-dodecane was employed, and culture medium with supplementation of complex sources was also optimized. As a result, 1.7 ± 0.1 g/L of styrene was produced in the flask cultures. Finally, fed-batch cultivations were performed in lab-scale bioreactor, and to minimize the loss of volatile styrene during the cultivation, three consecutive bottles containing n-dodecane were connected to the air outlet of bioreactor for gas-stripping. To conclude, the total titer of styrene was as high as 5.3 ± 0.2 g/L, which could be obtained at 60 h. CONCLUSION: We successfully engineered E. coli strain for the de novo production of styrene in both flask and fed-batch cultivation, and could achieve the highest titer for styrene in bacterial hosts reported till date. We believe that our efforts in strain engineering and ISPR strategy with organic solvent will provide a new insight for economic and industrial production of styrene in a biological platform.


Subject(s)
Escherichia coli/genetics , Escherichia coli/metabolism , Metabolic Engineering/methods , Microorganisms, Genetically-Modified/metabolism , Styrene/metabolism , Batch Cell Culture Techniques , Bioreactors
13.
Phys Rev Lett ; 121(16): 167003, 2018 Oct 19.
Article in English | MEDLINE | ID: mdl-30387624

ABSTRACT

We have examined the intrinsic spin-orbit coupling and orbital depairing in thin films of Nb-doped SrTiO_{3} by superconducting tunneling spectroscopy. The orbital depairing is geometrically suppressed in the two-dimensional limit, enabling a quantitative evaluation of the Fermi level spin-orbit scattering using Maki's theory. The response of the superconducting gap under in-plane magnetic fields demonstrates short spin-orbit scattering times τ_{so}≤1.1 ps. Analysis of the orbital depairing indicates that the heavy electron band contributes significantly to pairing. These results suggest that the intrinsic spin-orbit scattering time in SrTiO_{3} is comparable to those associated with Rashba effects in SrTiO_{3} interfacial conducting layers and can be considered significant in all forms of superconductivity in SrTiO_{3}.

14.
Nat Commun ; 9(1): 4008, 2018 10 01.
Article in English | MEDLINE | ID: mdl-30275443

ABSTRACT

Quantum ground states that arise at atomically controlled oxide interfaces provide an opportunity to address key questions in condensed matter physics, including the nature of two-dimensional metallic behaviour often observed adjacent to superconductivity. At the superconducting LaAlO3/SrTiO3 interface, a metallic ground state emerges upon the collapse of superconductivity with field-effect gating and is accompanied with a pseudogap. Here we utilize independent control of carrier density and disorder of the interfacial superconductor using dual electrostatic gates, which enables the comprehensive examination of the electronic phase diagram approaching zero temperature. We find that the pseudogap corresponds to precursor pairing, and the onset of long-range phase coherence forms a two-dimensional superconducting dome as a function of the dual-gate voltages. The gate-tuned superconductor-metal transitions are driven by macroscopic phase fluctuations of Josephson coupled superconducting puddles.

15.
Nat Commun ; 9(1): 4570, 2018 10 29.
Article in English | MEDLINE | ID: mdl-30374115

ABSTRACT

The original HTML version of this Article omitted to list Harold Y. Hwang as a corresponding author and incorrectly listed Adrian G. Swartz as a corresponding author. This has been corrected in the HTML version of the Article. The PDF version was correct from the time of publication.

16.
Int J Mol Sci ; 19(10)2018 Oct 17.
Article in English | MEDLINE | ID: mdl-30336555

ABSTRACT

Recently, anoctamin1 (ANO1), a calcium-activated chloride channel, has been considered an important drug target, due to its involvement in various physiological functions, as well as its possibility for treatment of cancer, pain, diarrhea, hypertension, and asthma. Although several ANO1 inhibitors have been discovered by high-throughput screening, a discovery of new ANO1 inhibitors is still in the early phase, in terms of their potency and specificity. Moreover, there is no computational model to be able to identify a novel lead candidate of ANO1 inhibitor. Therefore, three-dimensional quantitative structure-activity relationship (3D-QSAR) pharmacophore modeling approach was employed for identifying the essential chemical features to be required in the inhibition of ANO1. The pharmacophore hypothesis 2 (Hypo2) was selected as the best model based on the highest correlation coefficient of prediction on the test set (0.909). Hypo2 comprised a hydrogen bond acceptor, a hydrogen bond donor, a hydrophobic, and a ring aromatic feature with good statistics of the total cost (73.604), the correlation coefficient of the training set (0.969), and the root-mean-square deviation (RMSD) value (0.946). Hypo2 was well assessed by the test set, Fischer randomization, and leave-one-out methods. Virtual screening of the ZINC database with Hypo2 retrieved the 580 drug-like candidates with good potency and ADMET properties. Finally, two compounds were selected as novel lead candidates of ANO1 inhibitor, based on the molecular docking score and the interaction analysis. In this study, the best pharmacophore model, Hypo2, with notable predictive ability was successfully generated, and two potential leads of ANO1 inhibitors were identified. We believe that these compounds and the 3D-QSAR pharmacophore model could contribute to discovering novel and potent ANO1 inhibitors in the future.


Subject(s)
Anoctamin-1/antagonists & inhibitors , Molecular Docking Simulation , Quantitative Structure-Activity Relationship , Algorithms , Drug Evaluation, Preclinical , Humans , Inhibitory Concentration 50 , Reproducibility of Results
17.
BMC Bioinformatics ; 18(Suppl 7): 226, 2017 May 31.
Article in English | MEDLINE | ID: mdl-28617219

ABSTRACT

BACKGROUND: Recently, the metabolite-likeness of the drug space has emerged and has opened a new possibility for exploring human metabolite-like candidates in drug discovery. However, the applicability of metabolite-likeness in drug discovery has been largely unexplored. Moreover, there are no reports on its applications for the repositioning of drugs to possible enzyme modulators, although enzyme-drug relations could be directly inferred from the similarity relationships between enzyme's metabolites and drugs. METHODS: We constructed a drug-metabolite structural similarity matrix, which contains 1,861 FDA-approved drugs and 1,110 human intermediary metabolites scored with the Tanimoto similarity. To verify the metabolite-likeness measure for drug repositioning, we analyzed 17 known antimetabolite drugs that resemble the innate metabolites of their eleven target enzymes as the gold standard positives. Highly scored drugs were selected as possible modulators of enzymes for their corresponding metabolites. Then, we assessed the performance of metabolite-likeness with a receiver operating characteristic analysis and compared it with other drug-target prediction methods. We set the similarity threshold for drug repositioning candidates of new enzyme modulators based on maximization of the Youden's index. We also carried out literature surveys for supporting the drug repositioning results based on the metabolite-likeness. RESULTS: In this paper, we applied metabolite-likeness to repurpose FDA-approved drugs to disease-associated enzyme modulators that resemble human innate metabolites. All antimetabolite drugs were mapped with their known 11 target enzymes with statistically significant similarity values to the corresponding metabolites. The comparison with other drug-target prediction methods showed the higher performance of metabolite-likeness for predicting enzyme modulators. After that, the drugs scored higher than similarity score of 0.654 were selected as possible modulators of enzymes for their corresponding metabolites. In addition, we showed that drug repositioning results of 10 enzymes were concordant with the literature evidence. CONCLUSIONS: This study introduced a method to predict the repositioning of known drugs to possible modulators of disease associated enzymes using human metabolite-likeness. We demonstrated that this approach works correctly with known antimetabolite drugs and showed that the proposed method has better performance compared to other drug target prediction methods in terms of enzyme modulators prediction. This study as a proof-of-concept showed how to apply metabolite-likeness to drug repositioning as well as potential in further expansion as we acquire more disease associated metabolite-target protein relations.


Subject(s)
Drug Repositioning , Enzymes/metabolism , Antimetabolites/metabolism , Area Under Curve , Databases, Factual , Enzymes/chemistry , Gaucher Disease/drug therapy , Gaucher Disease/enzymology , Gaucher Disease/pathology , Glucosylceramidase/therapeutic use , Humans , ROC Curve
18.
Microb Cell Fact ; 15: 16, 2016 Jan 19.
Article in English | MEDLINE | ID: mdl-26785776

ABSTRACT

BACKGROUND: Plant parasitic nematodes are harmful to agricultural crops and plants, and may cause severe yield losses. Cinnamaldehyde, a volatile, yellow liquid commonly used as a flavoring or food additive, is increasingly becoming a popular natural nematicide because of its high nematicidal activity and, there is a high demand for the development of a biological platform to produce cinnamaldehyde. RESULTS: We engineered Escherichia coli as an eco-friendly biological platform for the production of cinnamaldehyde. In E. coli, cinnamaldehyde can be synthesized from intracellular L-phenylalanine, which requires the activities of three enzymes: phenylalanine-ammonia lyase (PAL), 4-coumarate:CoA ligase (4CL), and cinnamoyl-CoA reductase (CCR). For the efficient production of cinnamaldehyde in E. coli, we first examined the activities of enzymes from different sources and a gene expression system for the selected enzymes was constructed. Next, the metabolic pathway for L-phenylalanine biosynthesis was engineered to increase the intracellular pool of L-phenylalanine, which is a main precursor of cinnamaldehyde. Finally, we tried to produce cinnamaldehyde with the engineered E. coli. According to this result, cinnamaldehyde production as high as 75 mg/L could be achieved, which was about 35-fold higher compared with that in the parental E. coli W3110 harboring a plasmid for cinnamaldehyde biosynthesis. We also confirmed that cinnamaldehyde produced by our engineered E. coli had a nematicidal activity similar to the activity of commercial cinnamaldehyde by nematicidal assays against Bursaphelenchus xylophilus. CONCLUSION: As a potential natural pesticide, cinnamaldehyde was successfully produced in E. coli by construction of the biosynthesis pathway and, its production titer was also significantly increased by engineering the metabolic pathway of L-phenylalanine.


Subject(s)
Acrolein/analogs & derivatives , Escherichia coli/metabolism , Metabolic Engineering/methods , Acrolein/metabolism , Plasmids/genetics
19.
J Microbiol Biotechnol ; 26(2): 356-63, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26608168

ABSTRACT

Human papillomavirus (HPV), a non-enveloped, double-stranded DNA tumor virus, is a primary etiological agent of cervical cancer development. As a potential tool for prophylactic vaccination, the development of virus-like particles (VLPs) containing the HPV16 L1 capsid protein is highly desired. In this study, we developed a high-level expression system of the HPV16 L1 in Escherichia coli for the purpose of VLP development. The native gene of HPV16 L1 has many rare codons that cause the early termination of translation and result in the production of truncated forms. First, we optimized the codon of the HPV16 L1 gene to the preferable codons of E. coli, and we succeeded in producing the full-size HPV16 L1 protein without early termination. Next, to find the best host for the production of HPV16 L1, we examined a total of eight E. coli strains, and E. coli BL21(DE3) with the highest yield among the strains was selected. With the selected host-vector system, we did a fed-batch cultivation in a lab-scale bioreactor. Two different feeding solutions (complex and defined feeding solutions) were examined and, when the complex feeding solution was used, a 6-fold higher production yield (4.6 g/l) was obtained compared with that with the defined feeding solution.


Subject(s)
Capsid Proteins/biosynthesis , Capsid Proteins/genetics , Escherichia coli/genetics , Oncogene Proteins, Viral/biosynthesis , Oncogene Proteins, Viral/genetics , Bioreactors , Capsid Proteins/isolation & purification , Codon , Female , Humans , Oncogene Proteins, Viral/isolation & purification , Recombinant Proteins/biosynthesis , Recombinant Proteins/isolation & purification , Vaccines, Virus-Like Particle
20.
J Biomed Opt ; 19(1): 011005, 2014 Jan.
Article in English | MEDLINE | ID: mdl-23797986

ABSTRACT

We present high-resolution optical tomographic images of human red blood cells (RBC) parasitized by malaria-inducing Plasmodium falciparum (Pf)-RBCs. Three-dimensional (3-D) refractive index (RI) tomograms are reconstructed by recourse to a diffraction algorithm from multiple two-dimensional holograms with various angles of illumination. These 3-D RI tomograms of Pf-RBCs show cellular and subcellular structures of host RBCs and invaded parasites in fine detail. Full asexual intraerythrocytic stages of parasite maturation (ring to trophozoite to schizont stages) are then systematically investigated using optical diffraction tomography algorithms. These analyses provide quantitative information on the structural and chemical characteristics of individual host Pf-RBCs, parasitophorous vacuole, and cytoplasm. The in situ structural evolution and chemical characteristics of subcellular hemozoin crystals are also elucidated.


Subject(s)
Erythrocytes/chemistry , Erythrocytes/parasitology , Hemeproteins/chemistry , Holography/methods , Microscopy/methods , Plasmodium falciparum/chemistry , Tomography/methods , Algorithms , Humans , Image Processing, Computer-Assisted/methods , Malaria, Falciparum/blood , Refractometry
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