Protective effect of a freshwater alga, <Emphasis Type="Italic">Spirogyra</Emphasis> sp., against lipid peroxidation in vivo zebrafish and purification of antioxidative compounds using preparative centrifugal partition chromatography

A freshwater alga, Spirogyra sp., collected in shallow ponds in South Korea, was evaluated for its antilipid peroxidative effect against 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced in vivo zebrafish, and antioxidative compounds from the alga were efficiently identified using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS⁺) online high-performance liquid chromatography (HPLC) and preparative centrifugal partition chromatography. The ethyl acetate fraction of Spirogyra sp. (SPE) in each fraction showed the strongest 2,2-diphenyl-1-picrylhydrazyl scavenging activity and significantly scavenged 2′,7′-dichlorodihydrofluorescein diacetate and diphenyl-1-pyrenylphosphine fluorescence, respectively, in AAPH-induced zebrafish embryo without any cytotoxicity in the concentrations between 25 and 50 μg mL^?1. The two main antioxidative compounds in SPE were confirmed by ABTS⁺ online HPLC and were identified as gallic acid and methyl gallate, respectively, by HPLC–diode array detection (DAD)–electrospray ionization (ESI)/mass spectrometry (MS), ¹H- and ¹³C-NMR. We conclude therefore that Spirogyra sp. is rich in gallic acid and methyl gallate, and it might be useful as a strong antilipid peroxidation material.     

Microsatellite markers for the Ussuri white-toothed shrew (Soricidae: <Emphasis Type="Italic">Crocidura lasiura</Emphasis>) developed by Ion Torrent sequencing and their application to the shrew populations in disturbed forests

Understanding the impacts of forest management practices on genetic diversity is essential for effective animal management and conservation. We characterized novel microsatellite loci in the Ussuri white-toothed shrew (Crocidura lasiura Dobson, 1890) to test the impacts of anthropogenic thinning of forest trees on the shrew populations and their genetic diversity. Using Ion Torrent sequencing technology, we characterized 611 potential microsatellite markers with complete di- to tetra-nucleotide motifs, identifying nine polymorphic loci. The observed and expected heterozygosities across the nine loci were 0.526 and 0.527, respectively. Mean allelic diversity was 5.2 alleles per locus, with the mean polymorphism information content at 0.498. In comparison among shrew populations, which inhabited in the forests thinned in 2004 (CLA; n = 10), 2008 (CLB; n = 9) and 2014 (CLC; n = 3), the observed heterozygosities are similar among the three populations (0.525 at CLA, 0.532 at CLB and 0.519 at CLC), whereas the expected heterozygosities were much lower in population of CLC (0.377) than that of CLA (0.509) and CLB (0.533). The small sample size at CLC limited effective comparison and evaluation of the impact of forest thinning on genetic diversity in this shrew population. Future application of the species-specific microsatellite markers described here to a larger sample size would be valuable in estimating the ecological parameters of shrew populations associated with existing forest management practices.     

<Emphasis Type="Italic">Larkinella terrae</Emphasis> sp. nov., isolated from soil on Jeju Island,South Korea

A Gram-stain negative, non-motile, rod-shaped, aerobic bacterium, designated 15J8-8^T, was isolated from a soil sample collected on Jeju Island, South Korea, and characterized taxonomically using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain 15J8-8^T belongs to the family Cytophagaceae and is related to Larkinella bovis M2TB15^T (95.0%), ‘Larkinella harenae’ 15J9-9 (94.5%), Larkinella arboricola Z0532^T (93.2%), and Larkinella insperata LMG 22510^T (93.0%). The DNA G+C content of strain 15J8-8^T was 50.5 mol%. The detection of phosphatidylethanolamine and two unidentified polar lipids as major polar lipids; menaquinone-7 as the predominant quinone; and C_16:1 ω5c, C_16:0 N alcohol, and iso-C_15:0 as the major fatty acids also supported the affiliation of the isolate to the genus Larkinella. Based on its phenotypic properties and phylogenetic distinctiveness, strain 15J8-8^T should be classified in the genus Larkinella as representative of a novel species, for which the name Larkinella terrae sp. nov. is proposed. The type strain is 15J8-8^T (= KCTC 52001^T = JCM 31990^T).     

Acetobacter oryzifermentans sp. nov., isolated from Korean traditional vinegar and reclassification of the type strains of Acetobacter pasteurianus subsp. ascendens (Henneberg 1898) and Acetobacter pasteurianus subsp. paradoxus (Frateur 1950) as Acetobacter ascendens sp. nov., comb. nov.

Twelve Acetobacter pasteurianus-related strains with publicly available genomes in GenBank shared high 16S rRNA gene sequence similarity (>99.59%), but average nucleotide identity (ANI) and in silico DNA-DNA hybridization (DDH) values and multilocus sequence- and genome-based relatedness analyses suggested that they were divided into four different phylogenetic lineages. Relatedness analyses based on multilocus sequences, 1,194 core genes and whole-cell MALDI-TOF profiles supported that strains LMG 1590^T and LMG 1591 (previously classified as the type strains of A. pasteurianus subsp. ascendens and paradoxus, respectively) and strain SLV-7^T do not belong to A. pasteurianus. Strain SLV-7^T, isolated from Korean traditional vinegar, shared low ANI (<91.0%) and in silico DDH (44.2%) values with all other Acetobacter type strains analyzed in this study, indicating that strain SLV-7^T represents a new Acetobacter species. The phenotypic and chemotaxonomic analyses confirmed these results and therefore a new species named Acetobacter oryzifermentans sp. nov. is proposed with SLV-7^T (= KACC 19301^T = JCM 31096^T) as the type strain. Strains LMG 1590^T and LMG 1591 shared high ANI (99.4%) and in silico DDH (96.0%) values between them, but shared low ANI (<92.3%) and in silico DDH (<49.0%) values with other type strains analyzed in this study, indicating that strains LMG 1590^T and LMG 1591 should be reclassified into a new single species that should be named Acetobacter ascendens sp. nov., comb. nov., with LMD 51.1^T (= LMG 1590^T = NCCB 51001^T) as its type strain.     

Effects of Scopolamine and Melatonin Cotreatment on Cognition,Neuronal Damage,and Neurogenesis in the Mouse Dentate Gyrus

It has been demonstrated that melatonin plays important roles in memory improvement and promotes neurogenesis in experimental animals. We examined effects of melatonin on cognitive deficits, neuronal damage, cell proliferation, neuroblast differentiation and neuronal maturation in the mouse dentate gyrus after cotreatment of scopolamine (anticholinergic agent) and melatonin. Scopolamine (1 mg/kg) and melatonin (10 mg/kg) were intraperitoneally injected for 2 and/or 4 weeks to 8-week-old mice. Scopolamine treatment induced significant cognitive deficits 2 and 4 weeks after scopolamine treatment, however, cotreatment of scopolamine and melatonin significantly improved spatial learning and short-term memory impairments. Two and 4 weeks after scopolamine treatment, neurons were not damaged/dead in the dentate gyrus, in addition, no neuronal damage/death was shown after cotreatment of scopolamine and melatonin. Ki67 (a marker for cell proliferation)- and doublecortin (a marker for neuroblast differentiation)-positive cells were significantly decreased in the dentate gyrus 2 and 4 weeks after scopolamine treatment, however, cotreatment of scopolamine and melatonin significantly increased Ki67- and doublecortin-positive cells compared with scopolamine-treated group. However, double immunofluorescence for NeuN/BrdU, which indicates newly-generated mature neurons, did not show double-labeled cells (adult neurogenesis) in the dentate gyrus 2 and 4 weeks after cotreatment of scopolamine and melatonin. Our results suggest that melatonin treatment recovers scopolamine-induced spatial learning and short-term memory impairments and restores or increases scopolamine-induced decrease of cell proliferation and neuroblast differentiation, but does not lead to adult neurogenesis (maturation of neurons) in the mouse dentate gyrus following scopolamine treatment.     

Mutational inactivation of OprD in carbapenem-resistant Pseudomonas aeruginosa isolates from Korean hospitals

This study investigated the mechanisms underlying the carbapenem resistance of bloodstream isolates of Pseudomonas aeruginosa obtained from two Korean hospitals. Of the 79 P. aeruginosa isolates, 22 and 21 were resistant to imipenem and meropenem, respectively. The 22 imipenem-resistant P. aeruginosa isolates were classified into 7 sequence types (STs) and 13 pulsotypes. Twelve imipenem-resistant isolates from one hospital were found to belong to the international clone ST111. Two imipenem-resistant P. aeruginosa ST235 isolates carried the bla _IMP-6 gene, but the remaining 20 isolates did not produce carbapenemases. Mutations in the oprD gene and a related decrease in gene expression were found in 21 and 5 isolates, respectively. However, all imipenemresistant P. aeruginosa isolates showed no significant expression of OprD in the outer membrane as compared with that of carbapenem-susceptible PAO1 strain. Overexpression of genes associated with efflux pumps, including mexB, mexD, mexF, and mexY, was not found in any imipenem-resistant isolate. One imipenem-resistant P. aeruginosa isolate overexpressed the ampC gene. Our results show that the low permeability of drugs due to the mutational inactivation of OprD is primarily responsible for carbapenem resistance in bloodstream isolates of P. aeruginosa from Korean hospitals.