ABSTRACT
Strain DG7B(T) was isolated from a soil sample collected in Seoul, Republic of Korea and was observed to be a gram-negative, short-rod shaped and non-motile bacterium. Its 16S rRNA gene sequence is closely related to those of Hymenobacter terrae DG7A(T) (97.8 % similarity), H. soli PB17(T) (97.5 %), H. glaciei VUG-A130(T) (96.4 %), H. saemangeumensis GSR0100(T) (95.7 %), H. ruber PB156(T) (95.3 %), and H. antarcticus VUG-A42aa(T) (95.3 %). The low levels of DNA-DNA relatedness (<50.3 %) with the above species identified strain DG7B(T) as a novel species in the genus Hymenobacter. The genomic DNA G+C content was determined to be 54.9 %. Growth of strain DG7B(T) was observed at 12-30 °C (optimum at 25 °C) and pH 6.0-11.0 (optimum at pH 7). The cells tolerate <0.5 % NaCl. A UV-visible scan of an ethanol extract of the whole cell pigment showed absorbance peaks at 264.5, 320.0, and 481.5 nm, so the pigment type was determined to be 2'-hydroxyflexixanthin. Chemotaxonomic data showed that strain DG7B(T) possesses menaquinone-7 as the predominant isoprenoid quinone, sym-homospermidine as the major polyamine, phosphatidylethanolamine as the predominant polar lipid and iso-C15:0, anteiso-C15:0 and summed feature 3 (C16:1 ω7c/C16:1 ω7c) as the major fatty acids. Strain DG7B(T) showed low-level resistance to ultraviolet C. Based on the polyphasic analysis, it is concluded that strain DG7B(T) (=KCTC 32553(T) = KEMB 9004-166(T) = JCM 30008(T)) should be classified as the type strain of a novel Hymenobacter species, for which the name Hymenobacter rubidus sp. nov. is proposed.
Subject(s)
Chlamydiaceae/classification , Soil Microbiology , Bacterial Typing Techniques , Base Composition , Chlamydiaceae/genetics , Chlamydiaceae/isolation & purification , Chlamydiaceae/radiation effects , Genome, Bacterial , Microbial Viability/radiation effects , Phenotype , Phylogeny , RNA, Ribosomal, 16S/genetics , Radiation Tolerance/radiation effects , Sequence Analysis, DNA , Ultraviolet RaysABSTRACT
Water-filtered infrared A (wIRA) is radiation with a spectrum ranging from 780 to 1400 nm. Chlamydiaceae are obligate intracellular bacteria associated with various diseases in both animals and humans. A recent in vitro study demonstrated that wIRA combined with visible light (wIRA/VIS) has potential as a non-chemical method for the treatment of chlamydial infections without adversely affecting the cell viability. The aim of this study was to investigate the influence of various factors on the effect of wIRA/VIS on acute chlamydial infection, namely the impact of temperature, exposure intensity and infectious dose (multiplicity of infection) as well as the efficacy of the visible light component.We demonstrate that non-thermal effects contribute to the inhibition of acute chlamydial infection. Visible light enhances the inhibitory effect of wIRA on extracellular bacteria (elementary bodies or EBs).Moreover, the inhibitory effect of wIRA/VIS following treatment of EBs prior to infection correlated with increased irradiation intensity. The infectivity of mature chlamydial inclusions was significantly reduced upon wIRA/VIS exposure at all irradiation intensities investigated, suggesting the contribution of host cell factors to the anti-chlamydial effect of wIRA/VIS in the late stage of the developmental cycle. The effect of irradiation was not influenced by the infectious dose.
