Deinococcus swuensis sp. nov., a gamma-radiation-resistant bacterium isolated from soil

Strain DY59^T, a Gram-positive non-motile bacterium, was isolated from soil in South Korea, and was characterized to determine its taxonomic position. Phylogenetic analysis based on the 16S rRNA gene sequence of strain DY59^T revealed that the strain DY59^T belonged to the family Deinococcaceae in the class Deinococci. The highest degree of sequence similarities of strain DY59^T were found with Deinococcus radiopugnans KACC 11999^T (99.0%), Deinococcus marmoris KACC 12218^T (97.9%), Deinococcus saxicola KACC 12240^T (97.0%), Deinococcus aerolatus KACC 12745^T (96.2%), and Deinococcus frigens KACC 12220^T (96.1%). Chemotaxonomic data revealed that the predominant fatty acids were iso-C_15:0 (19.0%), C_16:1 ω7c (17.7%), C_15:1 ω6c (12.6%), iso-C_17:0 (10.3%), and iso-C_17:1 ω9c (10.3%). A complex polar lipid profile consisted of a major unknown phosphoglycolipid. The predominant respiratory quinone is MK-8. The cell wall peptidoglycan contained D-alanine, L-glutamic acid, glycine, and L-ornithine (di-amino acid). The novel strain showed resistance to gamma radiation, with a D₁₀ value (i.e. the dose required to reduce the bacterial population by 10-fold) in excess of 5 kGy. Based on the phylogenetic, chemotaxonomic, and phenotypic data, strain DY59^T (=KCTC 33033^T =JCM 18581^T) should be classified as a type strain of a novel species, for which the name Deinococcus swuensis sp. nov. is proposed.     

Sublingual administration of bacteria-expressed influenza virus hemagglutinin 1 (HA1) induces protection against infection with 2009 pandemic H1N1 influenza virus

Influenza viruses are respiratory pathogens that continue to pose a significantly high risk of morbidity and mortality of humans worldwide. Vaccination is one of the most effective strategies for minimizing damages by influenza outbreaks. In addition, rapid development and production of efficient vaccine with convenient administration is required in case of influenza pandemic. In this study, we generated recombinant influenza virus hemagglutinin protein 1 (sHA1) of 2009 pandemic influenza virus as a vaccine candidate using a well-established bacterial expression system and administered it into mice via sublingual (s.l.) route. We found that s.l. immunization with the recombinant sHA1 plus cholera toxin (CT) induced mucosal antibodies as well as systemic antibodies including neutralizing Abs and provided complete protection against infection with pandemic influenza virus A/CA/04/09 (H1N1) in mice. Indeed, the protection efficacy was comparable with that induced by intramuscular (i.m.) immunization route utilized as general administration route of influenza vaccine. These results suggest that s.l. vaccination with the recombinant non-glycosylated HA1 protein offers an alternative strategy to control influenza outbreaks including pandemics.     

Pontibacter jeungdoensis sp. nov., isolated from a solar saltern in Korea

A Gram-staining-negative, rod-shaped and red-pigmented bacterial strain, HMD3125^T, was isolated from a solar saltern in Jeungdo, Republic of Korea. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HMD3125^T formed a lineage within the genus Pontibacter and was similar to Pontibacter salisaro (96.1%) and P. korlensis (95.3%). The major fatty acids of strain HMD3125^T were summed feature 4 (comprising iso-C_17:1 I and/or anteiso-C_17:1 B; 30.4%), iso-C_15:0 (20.4%) and iso-C_17:0 3OH (17.2%). The polar lipid profile of HMD3125^T consisted of the phosphatidylethanolamine, four unidentified polar lipids, unidentified phospholipid, unidentified aminolipid and unidentified aminophospholipid. Strain HMD3125^T contained MK-7 as the predominant menaquinone and sym-homospermidine as the major polyamine. The DNA G+C content of strain HMD3125^T was 45.6 mol%. Strain HMD3125^T assigned as a novel species in the genus Pontibacter, for which the name Pontibacter jeungdoensis sp. nov. is proposed. The type strain is HMD3125^T (=KCTC 23156^T =CECT 7710^T).     

Chemical constituents isolated from Polygala japonica leaves and their inhibitory effect on nitric oxide production in vitro

A methanolic extract of dried leaves of Polygala japonica Houtt (Polygalaceae) significantly attenuated nitric oxide production in lipopolysaccharide-simulated BV2 microglia. Five anthraquinones chrysophanol (1), emodin (2), aloe-emodin (3), emodin 8-O-β-D-glucopyranoside (4) and trihydroxy anthraquinone (5), and four flavonoids kaempferol (6), chrysoeriol (7), kaempferol 3-gentiobioside (8) and isorhamnetin (9) were isolated from the methanolic extract using bioactivity-guided fractionation. Among them, compounds 1–4, 6 and 7 showed significant inhibitory effect on lipopolysaccharide-induced nitric oxide production in BV2 microglia at the concentrations ranging from 1.0 to 100.0 μM.     

Predicting the progress of colon cancer by DNA methylation markers of the p16 gene in feces - Evidence from an animal model

A new noninvasive screening tool for colorectal neoplasia detects epigenetic alterations exhibited by gastrointestinal tumor cells shed into stool. There is insufficient existing data to determine temporal associations between colorectal cancer (CRC) progression and aberrant DNA methylation. To evaluate the feasibility of using fecal DNA methylation status to determine CRC progression, we collected stool samples from 14 male SD rats aged six weeks, and administered subcutaneous injections of either 1,2-dimethylhydrazine or saline weekly. p16 DNA methylation statuses in tumorous and normal colon tissue, and from stool samples were determined using methylation-specific PCR. Additionally, p16 methylation was detected in stool DNA from 85.7% of the CRC rats. The earliest change in p16 methylation status in the DMH-treated group stool samples occurred during week nine; repeatabilities were 57.1% in week 19 (p = 0.070) and 85.7% in week 34 (p = 0.005). A temporal correlation was evidenced between progression of CRC and p16 methylation status, as evidenced by DMH-induced rat feces. Using fecal DNA methylation status to determine colorectal tissue methylation status can reveal CRC progression. Our data suggests that p16 promoter methylation is a feasible epigenetic marker for the detection and may be useful for CRC screening.     

Exosomes Derived from Mesenchymal Stem Cells Suppress Angiogenesis by Down-Regulating VEGF Expression in Breast Cancer Cells

Exosomes are small membrane vesicles released by a variety of cell types. Exosomes contain genetic materials, such as mRNAs and microRNAs (miRNAs), implying that they may play a pivotal role in cell-to-cell communication. Mesenchymal stem cells (MSCs), which potentially differentiate into multiple cell types, can migrate to the tumor sites and have been reported to exert complex effects on tumor progression. To elucidate the role of MSCs within the tumor microenvironment, previous studies have suggested various mechanisms such as immune modulation and secreted factors of MSCs. However, the paracrine effects of MSC-derived exosomes on the tumor microenvironment remain to be explored. The hypothesis of this study was that MSC-derived exosomes might reprogram tumor behavior by transferring their molecular contents. To test this hypothesis, exosomes from MSCs were isolated and characterized. MSC-derived exosomes exhibited different protein and RNA profiles compared with their donor cells and these vesicles could be internalized by breast cancer cells. The results demonstrated that MSC-derived exosomes significantly down-regulated the expression of vascular endothelial growth factor (VEGF) in tumor cells, which lead to inhibition of angiogenesis in vitro and in vivo. Additionally, miR-16, a miRNA known to target VEGF, was enriched in MSC-derived exosomes and it was partially responsible for the anti-angiogenic effect of MSC-derived exosomes. The collective results suggest that MSC-derived exosomes may serve as a significant mediator of cell-to-cell communication within the tumor microenvironment and suppress angiogenesis by transferring anti-angiogenic molecules.     

Secreted Frizzled-Related Protein 3 Regulates Activity-Dependent Adult Hippocampal Neurogenesis

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Highlights? Wnt inhibitor sFRP3 exhibits activity-dependent expression in the adult hippocampus ? sFRP3 maintains quiescence of adult hippocampal radial glia-like neural stem cells ? sFRP3 inhibits maturation, dendritic development, and spinal formation of new neurons ? sFRP3 partially mediates activity-dependent adult hippocampal neurogenesis