Application of an Antioxidant Response Element-Nuclear Factor Erythroid 2 Luciferase Assay for Assessing the Skin Sensitization Potential of Agrochemicals.

The skin sensitization potential of agrochemicals can be assessed using laboratory methods such as the keratinocyte activation assay so that their use in regulatory toxicology might replace experimental animal testing. Here, we evaluated the skin sensitization potential of 11 agrochemicals by using an antioxidant response element-nuclear factor erythroid 2 luciferase assay in KeratinoSens and LuSens cells and applying a skin sensitization adverse outcome pathway (AOP). The KeratinoSens and LuSens assays consistently evaluated the skin sensitization potential of 10/11 agrochemicals with reference to animal testing databases. Benomyl, pretilachlor, fluazinam, terbufos, butachlor, and carbosulfan were correctly detected as sensitizers, and glufosinate ammonium, oxiadiazon, tebuconazole, and etofenprox were correctly detected as non-sensitizers. For diazinon, the skin sensitizing potential was positive in the KeratinoSens assay but not in the LuSens assay. These results suggest that the evaluation of in vitro skin sensitization using the AOP mechanism can be applied to assess active agrochemicals.

Effectiveness of Cytochrome c Oxidase Subunit 1 Gene Nested Polymerase Chain Reaction Compared to Dermoscopy or Microscopy Alone for the Detection and Diagnosis of Sarcoptes scabiei var. hominis Infection.

BACKGROUND: Background: While microscopy (MS) evaluation of skin scrapings has a 100% positive predictive value and specificity by definition for scabies diagnosis, it has low sensitivity. Dermoscopy (DS) has not yet been widely accepted for diagnosis, and long-term clinician training is required. OBJECTIVE: To evaluate the diagnostic validity of cytochrome c oxidase subunit 1 (cox1) gene nested polymerase chain reaction (PCR) as an adjunctive method for diagnosing scabies. METHODS: This was a prospective, single institution study, conducted on a total of 302 skin lesions from 50 patients suspected of scabies at Kangdong Sacred Heart Hospital in Seoul, Korea. DS, MS, and cox1 nested PCR were performed on all patients. RESULTS: Of the 302 lesions, 145 (48.0%) were obtained at first visit and 157 (52.0%) were identified in the course of follow-up visits after treatment. For all lesions, DS and MS sensitivity levels were 55.9% (73/136) and 55.2% (75/136), respectively, with cox1 gene nested PCR considered as 100%. The results of DS and MS identification showed no difference between each other and showed significant difference from that of cox1 gene nested PCR. CONCLUSION: Nested PCR detecting cox1 may be prospectively used to comprehensively diagnose lesions of scabies in clinical practice.

Laxative effect of probiotic chocolate on loperamide-induced constipation in rats.

The fecal morphology, defecation frequency, bowel function, intestinal motility, and fecal bacterial composition were evaluated to investigate the laxative effect of probiotic chocolate containing Streptococcus thermophilus MG510 and Lactobacillus plantarum LRCC5193 (LYC) on loperamide-induced constipated rats. Daily oral administration of LYC in constipated rats for two weeks was shown to significantly increase (n = 14) the defecation frequency, fecal moisture content, and relative abundance of fecal Lactobacillus and Faecalibacterium prausnitzii. Moreover, histological analysis of the distal colon of constipated rats revealed that LYC treatment can also increase the thickness of the colonic mucosa and muscle layers, and crypt of Lieberkühn. LYC also significantly increased (n = 5) the intestinal motility and modulated (n = 9) mRNA expression levels of colonic ZO-1 and Cldn-1 in the constipated rats. Altogether, these results demonstrate that probiotic chocolate has potential as a dietary adjunct for the treatment of constipation.

Quorum sensing is a key regulator for the antifungal and biocontrol activity of chitinase-producing Chromobacterium sp. C61.

Chromobacterium sp. strain C61 has strong biocontrol activity; however, the genetic and biochemical determinants of its plant disease suppression activity are not well understood. Here, we report the identification and characterization of two new determinants of its biocontrol activity. Transposon mutagenesis was used to identify mutants that were deficient in fungal suppression. One of these mutants had an insertion in a homologue of depD, a structural gene in the dep operon, that encodes a protein involved in non-ribosomal peptide synthesis. In the second mutant, the insertion was in a homologue of the luxI gene, which encodes a homoserine lactone synthase. The luxI- and depD- mutants had no antifungal activity in vitro and a dramatically reduced capacity to suppress various plant diseases in planta. Antifungal production and biocontrol were restored by complementation of the luxI- mutant. Other phenotypes associated with effective biological control, including motility and lytic enzyme secretion, were also affected by the luxI mutation. Biochemical analysis of ethyl acetate extracts of culture filtrates of the mutant and wild-type strains showed that a key antifungal compound, chromobactomycin, was produced by wild-type C61 and the complemented luxI- mutant, but not by the luxI- or depD- mutant. These data suggest that multiple biocontrol-related phenotypes are regulated by homoserine lactones in C61. Thus, quorum sensing plays an essential role in the biological control potential of diverse bacterial lineages.

Persistent otolith dysfunction even after successful repositioning in benign paroxysmal positional vertigo.

To evaluate utricular and saccular function during the acute and resolved phases of BPPV, ocular and cervical vestibular evoked myogenic potentials (VEMPs) were studied in 112 patients with BPPV and 50 normal controls in a referral-based University Hospital. Ocular (oVEMPs) and cervical VEMPs (cVEMPs) were induced using air-conducted sound (1000Hz tone burst, 100dB normal hearing level) at the time of initial diagnosis and 2 months after successful repositioning in patients with BPPV, and the results were compared with those of the controls. Abnormalities of cVEMPs and oVEMPs in patients with BPPV were prevalent and significantly higher compare to the healthy control group (p<0.01 in each VEMP by chi-square test). In the patient group, difference between the proportions of abnormal responses of cVEMP and oVEMP was not significant in both affected (p=0.37, chi-squared test) and non-affected (p=1.00) ears. The abnormalities were more likely reduced or absent responses rather than delayed ones; reduced or absent responses are 17.6% in cVEMPs (p=0.04, chi-square) and 21.6% in oVEMPs (p<0.01). The non-affected ear in the BPPV group also showed significantly higher abnormalities of cVEMP and oVEMP when compared to the control group. The follow-up VEMPs after repositioning maneuvers were not significantly different compared to the initial values from both stimulated affected and non-affected ears. Although most patients had unilateral BPPV, bilateral otolithic dysfunction was often shown by persistently reduced or absent cervical and ocular VEMPs, suggesting that BPPV may be caused by significant bilateral damage to the otolith organs.

Permanent Bilateral Vision Loss in Eclamptic Posterior Reversible Encephalopathy Syndrome.

Posterior reversible encephalopathy syndrome (PRES) classically consists of reversible vasogenic oedema in the posterior circulation territories, which is reversible both clinically and radiologically in the majority of patients after the control of hypertension. The authors describe a 27-year-old eclamptic patient with PRES in accelerated hypertension who revealed permanent vision loss associated with bilateral Purtscher retinopathy. One of the two competing theories that explain vasogenic brain oedema in PRES is excessive autoregulation leading to the dilation of cerebral arterial vessels, particularly in the occipito-parietal vasculatures. Dysfunction of endothelial cells that results in constriction of vessels has also been hypothesised as a cause of PRES. The concurrence of bilateral vaso-occlusive retinopathy and PRES supports the hypothesis that vasoconstriction is a more plausible mechanism of vasogenic oedema in PRES.

Both extracellular chitinase and a new cyclic lipopeptide, chromobactomycin, contribute to the biocontrol activity of Chromobacterium sp. C61.

Chromobacterium sp. strain C61 displays antifungal activities in vitro and has been used successfully for the biocontrol of plant diseases under field conditions. In this study, the roles of extracellular chitinase and an antifungal compound produced by strain C61 were investigated to elucidate their contributions to biological control activity. The bacterium possessed a locus chi54 encoding an extracellular chitinase, and mutation of chi54 eliminated chitinase production. Production of the extracellular enzyme and expression of the chi54 transcript were increased in the wild-type strain when chitin was added to the culture medium. In vitro assays showed that purified chitinase inhibited spore germination of multiple pathogens. However, the in planta biocontrol activity of filtrates of cultures grown in the presence of chitin was lower than that of filtrates grown without chitin, indicating that correlation between chitinase and biocontrol activity was lacking. The analysis of C61 culture filtrates revealed an antifungal cyclic lipopeptide, chromobactomycin, whose structure contained a unique nonameric peptide ring. The purified chromobactomycin inhibited the growth of several phytopathogenic fungi in vitro, and plant application significantly reduced disease severity for several pathogens. Furthermore, the production of chromobactomycin was reduced in cultures amended with chitin. These data suggest that the production of both the extracellular chitinase Chi54 and the newly identified antibiotic chromobactomycin can contribute, in an interconnected way, to the suppression of plant disease by Chromobacterium sp. strain C61.

Identification of orfamide A as an insecticidal metabolite produced by Pseudomonas protegens F6.

The use of biosurfactants for agricultural crop protection has been gaining interest because they are generally biodegradable and environmentally friendly. In the present study, we identified an insecticidal biosurfactant produced by Pseudomonas protegens F6 (F6) and examined its use for aphid control. The growth of F6 was accompanied by increased aphid mortality and decreased water surface tension. Bioassay-guided chromatography coupled with instrumental analyses, nuclear magnetic resonance (NMR), and time-of-flight mass spectrometer (TOF MS) identified orfamide A as a major metabolite that showed insecticidal activity against green peach aphid ( Myzus persicae ). Orfamide A revealed a dose-dependent mortality against aphids, producing a LC50 value at 34.5 µg/mL, and caused a considerable decrease in the surface tension value of water, giving about 35.7 mN/m at 10 µg/mL. Laboratory and greenhouse mortality bioassays suggested that orfamide A may be applicable to control aphids in organic agriculture. This is the first report of orfamide A as an insecticidal metabolite against Myzus persicae .

Electrochromic properties of asymmetric 4,4'-bipyridinium nanocomposites with inorganic nanoparticles.

Asymmetric mono cationic 4,4'-bipyridiniums, 1-butyl-4,4'-bipyridinium bromide (BUBP) and 1-methyl-4,4'-bipyridinium iodide (MEBP) showed electrochromic properties from blue to transparent yellow. The electrochromic bipyridiniums, BUBP and MEBP, were introduced to solid state electrochromic cells by using a solution of the bipyridinium, TiO2, and polymer electrolyte composite. The 4,4'-bipyridinium derivatives was attached to TiO2 nanoparticles and decreased aggregation of TiO2 to afford EC dye-TiO2 nanoparticles with average diameter smaller than 20 nm, as determined by FE-SEM. An all solid state electrochromic cells prepared from the dye-TiO2 nanoparticles showed improved electrochromic response compared to that without TiO2. Thus the cell from the BUBP- TiO2 nanoparticles responded to a step potential of +/-2 V within 7 sec with coloration efficiency of 117. The redox cyclability of the bipyridinium-TiO2 nanoparticles cell was longer than that of the TiO2 free cells. The enhanced properties were attributed to the conductivity and the large surface area of TiO2 nanoparticles.