Rhodoferax bucti sp. nov., isolated from fresh water.

A Gram-reaction-negative, peach-brown-pigmented, slightly curved-rod-shaped, aerobic, non-motile bacterium, designated GSA243-2T, was isolated from fresh water samples collected from the Chishui River flowing through Maotai, Guizhou, south-west PR China. Phenotypic, chemotaxonomic and genomic traits were investigated. Results of phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate belonged to the genus Rhodoferax. The closest phylogenetic relative was Rhodoferax saidenbachensis ATCC BAA-1852T (98.35 %). The major fatty acids were C16: 0 and C16 : 1ω6c and/or C16 : 1ω7c. The major respiratory quinone was ubiquinone Q-8 and the major polar lipid was phosphatidylethanolamine. Genome sequencing revealed a genome size of 3.67 Mbp and a G+C content of 61.17 mol%. Pairwise-determined whole genome average nucleotide identity values and digital DNA-DNA hybridization values suggested that strain GSA243-2T represents a new species, for which we propose the name Rhodoferaxbucti sp. nov. with the type strain GSA243-2T (=CGMCC 1.16288T=KCTC 62564T).

Sphingomonas floccifaciens sp. nov., isolated from subterranean sediment.

A Gram-stain-negative, non-motile, non-sporulating, rod-shaped, orange-pigmented bacterium, designated strain FQM01T, was isolated from a subterranean sediment sample in the Mohe permafrost area, China. Strain FQM01T grew optimally at 25 °C, pH 7.0 and NaCl concentration of 0 % (w/v). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain FQM01T belonged to the genus Sphingomonas. The closest phylogenetic relative was Sphingomonas spermidinifaciens GDMCC 1.657T (97.6 %), followed by Sphingomonas mucosissima DSM 17494T (97.2 %). The DNA G+C content of the isolate was 66.9 mol%. Strain FQM01T contained Q-10 as the predominant ubiquinone, and C18 : 1ω6c and/or C18 : 1ω7c, C16 : 1ω6c and/or C16 : 1ω7c, C16 : 0, C14 : 0 2-OH and C18 : 1ω7c 11 methyl as the major fatty acids. Major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and an unidentified glycolipid. Only sym-homospermidine was detected as the polyamine. On the basis of phylogenetic and phenotypic data, strain FQM01T is considered to represent a novel species of Sphingomonas for which the name Sphingomonasfloccifaciens sp. nov. is proposed. The type strain is FQM01T (=CGMCC 1.15797T=KCTC 52630T).

Host-plant induced changes in microbial community structure and midgut gene expression in an invasive polyphage (Anoplophora glabripennis).

Polyphagous insect herbivores possess diverse mechanisms to overcome challenges of feeding in multiple plant species including, but not limited to, transcriptional plasticity and associations with obligate or facultative symbionts. The Asian longhorned beetle (Anoplophora glabripennis) is a polyphagous wood-feeder capable of developing on over 100 tree species and, like other polyphages, its genome contains amplifications of digestive and detoxification genes. This insect also possesses a diverse gut microbial community, which has the metabolic potential to augment digestive physiology. While the genomic repertoires of A. glabripennis and its microbial community have been studied previously, comparatively less is known about how the gut transcriptome and community change in response to feeding in different hosts. In this study, we show that feeding in two suitable hosts (Acer spp. and Populus nigra) altered the expression levels of multicopy genes linked to digestion and detoxification. However, feeding in a host with documented resistance (Populus tomentosa) induced changes in the transcriptome and community beyond what was observed in insects reared in P. nigra, including the downregulation of numerous ß-glucosidases, odorant binding proteins, and juvenile hormone binding proteins, the upregulation of several cuticular genes, and the loss of one major bacterial family from the gut community.

Immunosensor based on carbon nanotube/manganese dioxide electrochemical tags.

This article reports on carbon nanotube/manganese dioxide (CNT-MnO2) composites as electrochemical tags for non-enzymatic signal amplification in immunosensing. The synthesized CNT-MnO2 composites showed good electrochemical activity, electrical conductivity and stability. The electrochemical signal of CNT-MnO2 composites coated glassy carbon electrode (GCE) increased by nearly two orders of magnitude compared to bare GCE in hydrogen peroxide (H2O2) environment. CNT-MnO2 composite was subsequently validated as electrochemical tags for sensitive detection of α-fetoprotein (AFP), a tumor marker for diagnosing hepatocellular carcinoma. The electrochemical immunosensor demonstrated a linear response on a log-scale for AFP concentrations ranging from 0.2 to 100 ng mL(-1). The limit of detection (LOD) was estimated to be 40 pg mL(-1) (S/N=3) in PBS buffer. Further measurements using AFP spiked plasma samples revealed the applicability of fabricated CNT-MnO2 composites for clinical and diagnostic applications.