Laccase-mimicking Mn-Cu hybrid nanoflowers for paper-based visual detection of phenolic neurotransmitters and rapid degradation of dyes.

BACKGROUND: Laccase-based biosensors are efficient for detecting phenolic compounds. However, the instability and high cost of laccases have hindered their practical utilization. RESULTS: In this study, we developed hierarchical manganese dioxide-copper phosphate hybrid nanoflowers (H-Mn-Cu NFs) as excellent laccase-mimicking nanozymes. To synthesize the H-Mn-Cu NFs, manganese dioxide nanoflowers (MnO2 NFs) were first synthesized by rapidly reducing potassium permanganate using citric acid. The MnO2 NFs were then functionalized with amine groups, followed by incubation with copper sulfate for three days at room temperature to drive the coordination interaction between the amine moieties and copper ions and to induce anisotropic growth of the petals composed of copper phosphate crystals, consequently yielding H-Mn-Cu NFs. Compared with those of free laccase, at the same mass concentration, H-Mn-Cu NFs exhibited lower Km (~ 85%) and considerably higher Vmax (~ 400%), as well as significantly enhanced stability in the ranges of pH, temperature, ionic strength, and incubation periods evaluated. H-Mn-Cu NFs also catalyzed the decolorization of diverse dyes considerably faster than the free laccase. Based on these advantageous features, a paper microfluidic device incorporating H-Mn-Cu NFs was constructed for the convenient visual detection of phenolic neurotransmitters, including dopamine and epinephrine. The device enabled rapid and sensitive quantification of target neurotransmitters using an image acquired using a smartphone. CONCLUSIONS: These results clearly show that H-Mn-Cu NFs could be potential candidates to replace natural laccases for a wide range of applications in biosensing, environmental protection, and biotechnology.

Sphingomonas humi sp. nov., isolated from soil.

A gram-negative, non-motile, non-spore-forming, small, orange, rod-shaped bacterium was isolated from soil in South Korea and characterized to determine its taxonomic position. Phylogenetic analysis based on 16S rRNA gene sequence examination revealed that strain PB323(T) belongs to the family Sphingomonadaceae. The highest degree of sequence similarity was found with Sphingomonas kaistensis PB56(T) (98.9%), followed by Sphingomonas astaxanthinifaciens TDMA-17(T) (98.3%). Chemotaxonomic characteristics (the G+C content of the genomic DNA 69.0 mol%, Q-10 quinone system, C(18:1) omega7c/omega9t/omega12t, C(16:1) omega7c/C(15:0) iso 2OH, C(17:1) omega6c, and C16:0 as the major fatty acids) corroborated assignment of strain PB323(T) to the genus Sphingomonas. Results of physiological and biochemical tests clearly demonstrate that strain PB323(T) represents a distinct species and support its affiliation with the genus Sphingomonas. Based on these data, PB323(T) (=KCTC 12341(T) =JCM 16603T =KEMB 9004-003(T)) should be classified as a type strain of a novel species, for which the name Sphingomonas humi sp. nov. is proposed.

Variovorax ginsengisoli sp. nov., a denitrifying bacterium isolated from soil of a ginseng field.

A Gram-negative, aerobic or facultatively anaerobic, non-spore-forming, motile, rod-shaped bacterium (strain Gsoil 3165(T)) was isolated from soil of a ginseng field in Pocheon, South Korea. Its taxonomic position was determined by using a polyphasic approach. On the basis of 16S rRNA gene sequence analysis, strain Gsoil 3165(T) was shown to belong to the family Comamonadaceae, class Betaproteobacteria, and was related most closely to the type strains of Variovorax boronicumulans (98.9 % similarity), Variovorax paradoxus (98.3 %), Variovorax soli (98.2 %) and Variovorax dokdonensis (96.6 %). Levels of 16S rRNA gene sequence similarity between strain Gsoil 3165(T) and the type strains of other species in the family Comamonadaceae were less than 97.0 %. The G+C content of the genomic DNA of strain Gsoil 3165(T) was 66 mol%. Phenotypic and chemotaxonomic data (Q-8 as the major ubiquinone; C(16 : 0) and C(17 : 0) cyclo as major fatty acids) supported the affiliation of strain Gsoil 3165(T) to the genus Variovorax. The results of physiological and biochemical tests allowed the genotypic and phenotypic differentiation of strain Gsoil 3165(T) from recognized Variovorax species. Gsoil 3165(T) is therefore considered to represent a novel species of the genus Variovorax, for which the name Variovorax ginsengisoli sp. nov. is proposed. The type strain is Gsoil 3165(T) (=KCTC 12583(T) =LMG 23392(T)).

Can magnetic resonance imaging provide clues to the inner ear functional status of enlarged vestibular aqueduct subjects with PDS mutation?

OBJECTIVES: The goal of this study was to characterize the signal intensity (SI) pattern in the endolymphatic duct/sac from T2-weighted spin echo magnetic resonance (MR) images and T2*-weighted 3-dimensional (3-D) constructive interference in steady state (CISS) MR images that were obtained from a homogenous group of patients with an enlarged vestibular aqueduct (EVA) associated with SLC264 (PDS) mutations. STUDY DESIGN: A retrospective study. SETTING: Tertiary referral center. PATIENTS: Eleven subjects (22 ears), with at least 1 SLC26A4 mutation and bilateral EVA confirmed by temporal bone computed tomography, were enrolled. INTERVENTION: The MR images of 22 ears were reviewed retrospectively. MAIN OUTCOME MEASURES: The SI of the endolymphatic sac (ES) from 2 sequences were compared and reviewed. The presence of anomalies of the vestibule were also evaluated. In addition, the caloric test results were also reviewed to characterize the vestibular function in a subset of our cohort (12 ears). RESULTS: T2*-weighted 3-D CISS MR images revealed a more variable SI in the enlarged endolymphatic system than did the T2-weighted images. There was a hierarchy for the order of SI loss from the endolymphatic system on the T2*-weighted 3-D CISS MR images. There were 3 cases where the SI loss from the intraosseous ES, on the T2*-weighted 3-D CISS images, was associated with an abnormal caloric response. CONCLUSION: The SI of the ES observed on T2*-weighted 3-D CISS images of EVA patients, with SLC26A4 mutations, showed a distinctive pattern, and the results from this study suggest a potential role for the MR imaging in providing physicians with better information about the functional status of the inner ear.

The Usefulness of Rectified VEMP.

OBJECTIVES: For a reliable interpretation of left-right difference in Vestibular evoked myogenic potential (VEMP), the amount of sternocleidomastoid muscle (SCM) contraction has to be considered. Therefore, we can ensure that a difference in amplitude between the right and left VEMPs on a patient is due to vestibular abnormality, not due to individual differences of tonic muscle activity, fatigue or improper position. We used rectification to normalize electromyograph (EMG) based on pre-stimulus EMG activity. This study was designed to evaluate and compare the effect of rectification in two conventional ways of SCM contraction. METHODS: Twenty-two normal subjects were included. Two methods were employed for SCM contraction in a subject. First, subjects were made to lie flat on their back, lifting the head off the table and turning to the opposite side. Secondly, subjects push with their jaw against the hand-held inflated cuff to generate cuff pressure of 40 mmHg. From the VEMP graphs, amplitude parameters and inter-aural difference ratio (IADR) were analyzed before and after EMG rectification. RESULTS: Before the rectification, the average IADR of the first method was not statistically different from that of the second method. The average IADRs from each method decreased in a rectified response, showing significant reduction in asymmetry ratio. The lowest average IADR could be obtained with the combination of both the first method and rectification. CONCLUSION: Rectified data show more reliable IADR and may help diagnose some vestibular disorders according to amplitude-associated parameters. The usage of rectification can be maximized with the proper SCM contraction method.

Improvement of atopic dermatitis in NC/Nga mice by topical application of CpG phosphodiester-ODN.

Atopic dermatitis (AD) is a chronic inflammatory skin disease with pruritic and eczematous lesions characterized by increased total IgE level, inflammatory cell infiltration, and the elevated expression of Th2 cytokines. Synthetic oligodeoxynucleotides containing unmethylated CpG dinucleotides are known to have immunostimulatory activities in mice and to convert from Th2 to Th1 immune responses in AD. Previous work has shown clinical effectiveness of CpG phosphorothioate-ODN in AD mice model. However, due to longer in vivo half-life and the possibility of causing unwanted side effects, therapeutic use of CpG phosphorothioate-ODN can be limited. Thus, we investigated the efficacy of CpG phosphodiester-ODN with a novel sequence in NC/Nga mice. Topical application of phosphodiester-ODN penetrated rapidly from epidermis to the lymph nodes, accompanied by reduced infiltration of inflammatory cells and decreased number of cells expressing cytokines such as IL-4, IL-10 and IFN-gamma. Furthermore, the expression of IFN-gamma was reduced in the CpG ODNs-treated NC/Nga mice while the expression of IL-12p40 was increased, suggesting stimulation of Th1 immune response. The expression of IL-10 was strongly reduced, which meant the suppression of Th2 immune response in NC/Nga mice, accompanied by reduced level of IgE and IgG1, but increased level of IgG2a in sera. Since phosphodiester-ODN has been shown to cause minimum side effect comparing its phosphorothioate counterpart, it is proposed to become a new therapeutic modality for AD.

Anxiolytic effects of the aqueous extract of Uncaria rhynchophylla.

The purpose of this study was to characterize the putative anxiolytic-like effects of the aqueous extract of hooks with stem of Uncaria rhynchophylla using the elevated plus maze (EPM) and the hole-board apparatus in rats and mice. Control rats were treated with an equal volume of saline, and positive control rats with buspirone (1 mg/kg). Single or repeated treatments of the aqueous extract of Uncaria rhynchophylla (200 mg/kg/day, p.o.) for 7 days significantly increased the time-spent and entries into open arms of the EPM, and reduced the time-spent and entries into the closed arms versus saline controls (P<0.05). However, no changes in spontaneous locomotor activity or myorelaxant effects were observed versus saline controls. In the hole-board test, repeated treatment with the aqueous extract of Uncaria rhynchophylla (100 or 200 mg/kg/day, p.o.) significantly increased the number of head-dips (P<0.05). In addition, the anxiolytic-like effects of Uncaria rhynchophylla extract as assessed using the EPM test were abolished by WAY 100635 (0.3 mg/kg, i.p.), a 5-HT(1A) receptor antagonist. These results suggest that Uncaria rhynchophylla is an effective anxiolytic agent, and acts via the serotonergic nervous system.

Potent inhibitory effects of N-aryl S-alkylthiocarbamate derivatives on the dopa oxidase activity of mushroom tyrosinase.

This study reports the potent inhibitory effect of N-aryl S-alkylthiocarbamate derivatives on mushroom tyrosinase (MT) activity. N-Aryl S-alkylthiocarbamate derivatives were found to exhibit a potent inhibitory effect on the dopa (3,4-dihydroxyphenylalanine) oxidase activity of mushroom tyrosinase. Most of the N-aryl S-alkylthiocarbamate derivatives (compounds from A to J) exhibited higher inhibitory effects than kojic acid (IC50=318 microM), a well known tyrosinase inhibitor. Tyrosinase was the most inhibited by S-phenetyl N-phenylthiocarbamate (compound E, IC50=7.25 microM), and this inhibition was 44 times stronger than that of kojic acid. Compound E exhibited 95.0% of inhibition at 100 microM. A kinetic study of MT inhibition by compound E using the Lineweaver-Burk plots analysis was performed. And the kinetics profiles observed suggest that compound E competitively inhibits MT.

Ethyl acetate soluble fraction of Cnidium officinale MAKINO inhibits neuronal cell death by reduction of excessive nitric oxide production in lipopolysaccharide-treated rat hippocampal slice cultures and microglia cells.

In the present work, we found that the ethyl acetate-soluble fraction of Cnidium officinale MAKINO (COEA) decreased nitric oxide (NO) production in the lipopolysaccharide (LPS)-stimulated BV-2 and primary microglia and suppressed expression of inducible nitric oxide synthase (iNOS) in BV-2 cells with the same pattern of NO production. In addition, we showed that excessive NO production played an important role in neuronal cell death in LPS-treated rat hippocampal slice cultures. Our data suggest that the COEA inhibits neuronal cell death by reduction of excessive NO production in LPS-treated rat hippocampal slice cultures. The ethyl acetate-soluble fraction of C. officinale reduced propidium iodide uptake and NO production in cultured media at the same time.

Neuroprotection by methanol extract of Uncaria rhynchophylla against global cerebral ischemia in rats.

In traditional Oriental medicine, Uncaria rhynchophylla has been used to lower blood pressure and to relieve various neurological symptoms. However, scientific evidence related to its effectiveness or precise modes of action has not been available. Thus, in the current study, we evaluated neuroprotective effects of U. rhynchophylla after transient global ischemia using 4-vessel occlusion model in rats. Methanol extract of U. rhynchophylla administered intraperitoneally (100-1000 mg/kg at 0 and 90 min after reperfusion) significantly protected hippocampal CA1 neurons against 10 min transient forebrain ischemia. Measurement of neuronal cell density in CA1 region at 7 days after ischemia by Nissl staining revealed more than 70% protection in U. rhynchophylla-treated rats compared to saline-treated animals. In U. rhynchophylla-treated animals, induction of cyclooxygenase-2 in hippocampus at 24 hr after ischemia was significantly inhibited at both mRNA and protein levels. Furthermore, U. rhynchophylla extract inhibited TNF-alpha and nitric oxide production in BV-2 mouse microglial cells in vitro. These anti-inflammatory actions of U. rhynchophylla extract may contribute to its neuroprotective effects.