Aim Preventing leaving-without-being-seen (LWBS) in children is crucial due to their inability to seek medical care independently. Because there are no studies of LWBS in Japan, the extent of this problem in Japan and its impacts on healthcare are uncertain. The present study seeks to fill this gap by investigating LWBS after triage and identifying the associated factors.
View Article and Find Full Text PDFβ-Glucose 1-phosphate (βGlc1P) is a donor substrate in the synthesis of various α-glucosides by glycoside phosphorylases belonging to the glycoside hydrolase family 65. This study presents an efficient synthesis of βGlc1P combining enzymatic phosphorolysis of inexpensive maltose and baker's yeast fermentation to bias the equilibrium toward maltose phosphorolysis by removing released glucose. Mass production of βGlc1P was obtained in a 2 L reaction mixture initially containing 500 mM maltose and inorganic phosphate, with a yield of 76 %.
View Article and Find Full Text PDFBackground: Nasogastric tube syndrome is a rare but life-threatening complication of nasogastric tube placement due to acute upper airway obstruction caused by bilateral vocal cord paresis.
Case Presentation: An 86-year-old woman was brought to the emergency department with acute stridor. She had been diagnosed with stroke 106 days prior, and an 8F nasogastric tube was placed on the day following the diagnosis.
Glycoside phosphorylases (GPs), which catalyze the reversible phosphorolysis of glycosides, are promising enzymes for the efficient production of glycosides. Various GPs with new catalytic activities are discovered from uncharacterized proteins phylogenetically distant from known enzymes in the past decade. In this study, we characterized Paenibacillus borealis PBOR_28850 protein, belonging to glycoside hydrolase family 94.
View Article and Find Full Text PDFGlycoside hydrolase family 65 (GH65) comprises glycoside hydrolases (GHs) and glycoside phosphorylases (GPs) that act on α-glucosidic linkages in oligosaccharides. All previously reported bacterial GH65 enzymes are GPs, whereas all eukaryotic GH65 enzymes known are GHs. In addition, to date, no crystal structure of a GH65 GH has yet been reported.
View Article and Find Full Text PDFStreptomycetes are characterized by their ability to produce structurally diverse compounds as secondary metabolites and by their complex developmental life cycle, which includes aerial mycelium formation and sporulation. The production of secondary metabolites is growth-stage dependent, and generally coincides with morphological development on a solid culture. Streptomyces sp.
View Article and Find Full Text PDFIn our screening program for new biologically active compounds, a new polyene macrolide, lavencidin (1), along with known compound RKGS-A2215A (2), was isolated from the fermentation broth of Streptomyces lavendulae FRI-5 by changing the composition of liquid medium normally used for the strain. Their structures were elucidated by spectral methods (high-resolution fast-atom bombardment mass spectrometry (HRFABMS) and nuclear magnetic resonance (NMR)). Compound 1 includes a conjugated pentaene moiety together with six hydroxy groups and a carboxylic acid as a side chain.
View Article and Find Full Text PDF3-O-Substituted reducing aldoses are commonly unstable under heat treatment at neutral and alkaline pH. In this study, to evaluate the decomposition products, nigerose (3-O-α-d-glucopyranosyl-d-glucose) and 3-O-methyl glucose were heated at 90 °C in 100 mM sodium phosphate buffer (pH 7.5).
View Article and Find Full Text PDFBoth aortic dissection and tension pneumothorax are conditions that require urgent treatments. However, the diagnosis of these emergencies is sometimes challenging because of various symptoms and difficulty obtaining their medical history due to severe conditions. Here, we present the case of a patient with type A aortic dissection associated with tension pneumothorax.
View Article and Find Full Text PDFSpirotetronate compounds are polyketide secondary metabolites with diverse biological functions, such as antibacterial, antitumor and antiviral activities. Three pure spirotetronate compounds (2EPS-A, -B, -C) isolated from Actinomadura strain 2EPS showed inhibitory activity against dengue virus serotype 2 (DENV-2). 2EPS-A, -B and -C demonstrated the LC values of 11.
View Article and Find Full Text PDFβ-Carboline alkaloids exhibit a broad spectrum of pharmacological and biological activities and are widely distributed in nature. Genetic information on the biosynthetic mechanism of β-carboline alkaloids has not been accumulated in bacteria, because there are only a few reports on the microbial β-carboline compounds. We previously isolated kitasetaline, a mercapturic acid derivative of a β-carboline compound, from the genetically modified Kitasatospora setae strain and found a plausible biosynthetic gene cluster for kitasetaline.
View Article and Find Full Text PDFβ-Carboline alkaloids and related compounds show a broad spectrum of biological activities. We previously identified new members of the β-carboline alkaloid family by using an engineered Kitasatospora setae strain and a heterologous Streptomyces host expressing the plausible biosynthetic genes, including the hypothetical gene kse_70640 (kslB). Here, we elucidated the chemical structure of a new tetrahydro-β-carboline compound (named kitasetalic acid) that appeared in a heterologous Streptomyces host expressing the kslB gene alone.
View Article and Find Full Text PDFFunctionally related genes often form a large gene cluster on fungal genomes. To analyze, by heterologous expression system, overall pathway in which a series of related genes are involved, the whole gene cluster should be introduced intact into the host strain. However, the construction of a genomic library based on cosmid or bacterial artificial chromosome, and screening of a clone harboring the target region are time consuming and usually require additional cloning of missing regions.
View Article and Find Full Text PDFWe identified a new cyclic lipodepsipeptide, cystargamide B (1), from the mycelial extract of a Kaempferia galanga rhizome-derived actinomycete strain, Streptomyces sp. PB013. The planar structure was elucidated based on high resolution fast-atom bombardment mass spectrometry (HRFABMS) spectroscopy and one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopic data.
View Article and Find Full Text PDFChemically inducible transcription factors are widely used to control gene expression of synthetic devices. The bacterial quorum sensing system is a popular tool to achieve such control. However, different quorum sensing systems have been found to cross-talk, both between themselves and with the hosts of these devices, and they are leaky by nature.
View Article and Find Full Text PDFIn streptomycetes, autoregulators are important signaling compounds that trigger secondary metabolism, and they are regarded as hormones based on their extremely low effective concentrations (nM) and the involvement of specific receptor proteins. Our previous distribution study revealed that butenolide-type hormones, including avenolide, are a general class of signaling molecules in streptomycetes and that strain J1074 may produce butenolide-type hormones. Here, we describe metabolite profiling of a disruptant of the gene, which encodes a key biosynthetic enzyme for butenolide-type hormones, and identify four butenolide compounds from J1074 that show avenolide activity.
View Article and Find Full Text PDFPhthoxazolin A, an oxazole-containing polyketide, has a broad spectrum of anti-oomycete activity and herbicidal activity. We recently identified phthoxazolin A as a cryptic metabolite of Streptomyces avermitilis that produces the important anthelmintic agent avermectin. Even though genome data of S.
View Article and Find Full Text PDFThe genome of streptomycetes has the ability to produce many novel and potentially useful bioactive compounds, but most of which are not produced under standard laboratory cultivation conditions and are referred to as silent/cryptic secondary metabolites. Streptomyces lavendulae FRI-5 produces several types of bioactive compounds. However, this strain may also have the potential to biosynthesize more useful secondary metabolites.
View Article and Find Full Text PDFAutoregulators are low-molecular-weight signaling compounds that control the production of many secondary metabolites in actinomycetes and have been referred to as 'Streptomyces hormones'. Here, potential producers of Streptomyces hormones were investigated in 40 Streptomyces and 11 endophytic actinomycetes. Production of γ-butyrolactone-type (IM-2, VB) and butenolide-type (avenolide) Streptomyces hormones was screened using Streptomyces lavendulae FRI-5 (ΔfarX), Streptomyces virginiae (ΔbarX) and Streptomyces avermitilis (Δaco), respectively.
View Article and Find Full Text PDFA new cyclic depsipeptide, rakicidin F (1), along with the known compound rakicidin C (2), was isolated from the fermentation broth of the marine sponge-derived actinomycete strain Streptomyces sp. GKU 220. Their structures were elucidated by interpreting the HRFABMS and NMR spectroscopic data.
View Article and Find Full Text PDFThe genomes of actinomycetes encode many cryptic novel/useful bioactive compounds, but access to these cryptic secondary metabolites remains limited. Streptomyces avermitilis predominantly produces three polyketide antibiotics (avermectin, filipin, and oligomycin) but has the potential to produce more secondary metabolites based on the number of cryptic biosynthetic gene clusters. Here, we extensively investigated the metabolite profiles of a gene disruptant of AvaR3 (an autoregulator receptor homologue), which is involved in the pleiotropic regulation of antibiotic production and cell morphology.
View Article and Find Full Text PDFStreptomyces lavendulae FRI-5 produces the blue pigment indigoidine and other secondary metabolites (d-cycloserine and nucleoside antibiotics). The production of these useful compounds is controlled by a signaling cascade mediated by the γ-butyrolactone autoregulator IM-2. Previously we revealed that the far regulatory island includes the IM-2 receptor, the IM-2 biosynthetic enzyme, and several transcriptional regulators, and that it contributes to the regulation of indigoidine production in response to the signaling molecule.
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