Microbiome analysis of the restricted bacteria in radioactive element-containing water at the Fukushima Daiichi Nuclear Power Station

A major incident occurred at the Fukushima Daiichi Nuclear Power Station following the tsunami triggered by the Tohoku-Pacific Ocean Earthquake in March 2011, whereby seawater entered the torus room in the basement of the reactor building. Here, we identify and analyze the bacterial communities in the torus room water and several environmental samples. Samples of the torus room water (1 × 109 Bq137Cs/L) were collected by the Tokyo Electric Power Company Holdings from two sampling points between 30 cm and 1 m from the bottom of the room (TW1) and the bottom layer (TW2). A structural analysis of the bacterial communities based on 16S rRNA amplicon sequencing revealed that the predominant bacterial genera in TW1 and TW2 were similar. TW1 primarily contained the genus Limnobacter, a thiosulfate-oxidizing bacterium. γ-Irradiation tests on Limnobacter thiooxidans, the most closely related phylogenetically found in TW1, indicated that its radiation resistance was similar to ordinary bacteria. TW2 predominantly contained the genus Brevirhabdus, a manganese-oxidizing bacterium. Although bacterial diversity in the torus room water was lower than seawater near Fukushima, ~70% of identified genera were associated with metal corrosion. Latent environment allocation-an analytical technique that estimates habitat distributions and co-detection analyses-revealed that the microbial communities in the torus room water originated from a distinct blend of natural marine microbial and artificial bacterial communities typical of biofilms, sludge, and wastewater. Understanding the specific bacteria linked to metal corrosion in damaged plants is important for advancing decommissioning efforts.

IMPORTANCE

In the context of nuclear power station decommissioning, the proliferation of microorganisms within the reactor and piping systems constitutes a formidable challenge. Therefore, the identification of microbial communities in such environments is of paramount importance. In the aftermath of the Fukushima Daiichi Nuclear Power Station accident, microbial community analysis was conducted on environmental samples collected mainly outside the site. However, analyses using samples from on-site areas, including adjacent soil and seawater, were not performed. This study represents the first comprehensive analysis of microbial communities, utilizing meta 16S amplicon sequencing, with a focus on environmental samples collected from the radioactive element-containing water in the torus room, including the surrounding environments. Some of the identified microbial genera are shared with those previously identified in spent nuclear fuel pools in countries such as France and Brazil. Moreover, our discussion in this paper elucidates the correlation of many of these bacteria with metal corrosion.

Complete genome sequence of Limnobacter thiooxidans CS-K2T, isolated from freshwater lake sediments in Bavaria, Germany

Limnobacter thiooxidans CS-K2T is a Gram-negative bacterium first isolated from the sediment of the littoral zone of a freshwater lake in Germany. We here present the complete annotated genome sequence of this thiosulfate-oxidizing bacterium, spanning 3.54 Mb and encoding 3,192 protein-coding sequences.

Studies on the constituents from the aerial part of Baccharis dracunculifolia DC

Ten new glycosides, named dracunculifosides A-J, were isolated along with sixteen known glycosides from the aerial part of Baccharis dracunculifolia DC. (Compositae). The structures of these glycosides were determined on the basis of spectral and chemical evidence. These new glycosides consisted of beta-D-glucopyranose or beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranose, and most possess an (E)-caffeoyl group.

Successive determinations of platinum(II) and selenium(IV) with 1,4-dibromo-2,3-diaminonaphthalene in aqueous micellar solutions

Highly sensitive successive determinations for PtII and SeIV ions have been developed based upon reactions with 1,4-dibromo-2,3-diaminonaphthalene (Br2DAN), which forms a near-infrared (NIR) absorbing complex (epsilon = 1.2 x 10(5) l mol-1 cm-1 at 800 nm) and an emissive complex (ex. 386 nm, em. 604 nm) for PtII and SeIV ions, respectively, in acidic aqueous micellar solutions. In the presence of a cationic surfactant, cetyltrimethylammonium chloride, the detection limits for PtII and SeIV ions are 1.2 ng ml-1 (3 sigma) and 0.98 ng ml-1 (S/N = 3), respectively. Hydrobromic acid plays a key role to enhance the color development of the NIR-absorbing PtII complex. The influences of CuII and ZnII ions at the normal human serum levels are readily tolerated, and interference from FeIII ion at 35 mumol l-1 is circumvented by the addition of 50 mumol l-1 of polyaminocarboxylates, such as EDTA.

Bufadienolides and a new lignan from the bulbs of Urginea maritima

Thirty three compounds were obtained from the bulbs of Urginea maritima (Liliaceae). The compounds were identified by means of fast atom bombardment mass spectrometry (FAB-MS), nuclear magnetic resonance (1H-NMR), (13C-NMR), nuclear overhauser effects (NOE) and two dimensional (2D) NMR. Ten of them were new natural compounds. Nine were bufadienolides and only one was lignan in these compounds.

Cardenolide and oxypregnane glycosides from the root of Asclepias incarnata L

Twenty-nine new oxypregnane glycosides were obtained along with two known cardenolides, frugoside and gofruside, and three known 12-O-acylated pregnane glycosides from the roots of Asclepias incarnata L. (Asclepiadaceae). By detailed studies of the 1H- and 13C-NMR spectra, the structures were determined to be tri- to penta glycosides of isolineolon, 12-O-acetyllineolon, ikemagenin, 12-O-benzoylisolineolon, and two new 12-O-acylated pregnanes.

Steroidal glycosides from the aerial part of Asclepias incarnata

The aerial part of Asclepias incarnata afforded 34 pregnane glycosides. These were confirmed to have lineolon, isolineolon, ikemagenin, 12-O-nicotinoyllineolon, deacylmetaplexigenin, metaplexigenin, rostratamine, 12-O-acetyllineolon, 15beta-hydroxylineolon and 15beta-hydroxyisolineolon moieties as their aglycones, and 2.6-dideoxyhexopyranose, glucopyranose and allopyranose as the corresponding sugar constituents. Their structures were determined using both spectroscopic and chemical methods.

Steroidal glycosides from the aerial part of Asclepias incarnata L. II

Thirty new steroidal glycosides were obtained from the aerial part of Asclepias incarnata L. (Asclepiadaceae). These glycosides were confirmed to have lineolon, isolineolon, 12-O-acetyllineolon, 12-O-(Z)-cinnamoyllineolon, metaplexigenin, 15 beta-hydroxylineolon, 15 beta-hydroxyisolineolon, 16 alpha-hydroxyisolineolon, 12-O-tigloyl-16 alpha-hydroxyisolineolon as the aglycone and 2,6-dideoxyhexopyranose as the sugar sequence by spectroscopic methods and chemical evidence.

Steroidal glycosides from roots of Cynanchum caudatum M. II

The roots of Cynanchum caudatum M. (Asclepiadaceae) afforded eleven new pregnane glycosides which had cynanchogenin, caudatin, 12-O-benzoyllineolon and 12-O-benzoyldeacylmetaplexigenin as the aglycone moiety and 2,6-dideoxy-3-O-methylhexopyranoses as component sugars. The structures of these compounds were elucidated by spectroscopic methods and from chemical evidence.

Steroidal glycosides from Cynanchum caudatum

The aerial part of Cynanchum caudatum afforded 10 new pregnane glycosides which had sarcostin or deacylmetaplexigenin as the aglycone moiety. The structures of these compounds were elucidated by spectroscopic methods and from chemical evidence.

Steroidal glycosides and cardenolide glycosides from Asclepias fruticosa

Asclepias fruticosa afforded, in addition to five known pregnane glycosides and 11 known cardenolide glycosides, four new pregnane glycosides and eleven new cardenolide glycosides. Structures of these compounds were elucidated by spectroscopic methods and from chemical evidence.

Steroidal glycosides from Asclepias fruticosa L

Five novel steroidal glycosides 2-6 were isolated from the whole plant of Asclepias fruticosa L. (Asclepiadaceae). The structures of these steroidal glycosides were determined on the basis of spectral and chemical evidence. All of these glycosides contain 2,6-dideoxyhexopyranoses as component sugars and their structures were elucidated as polyoxypregnane-type glycosides, which have lineolon as the aglycone moiety.