Dual-isotope imaging method for Actinium-225 and Bismuth-213 using alpha imaging detector.

Recently, 225Ac has received considerable attention for its use in targeted alpha therapy because it has a relatively long half-life and yields four more alpha-particles from the daughter nuclides. The performance evaluation should separately assess the distribution of 225Ac and 213Bi because daughter nuclides, including 213Bi, can cause renal toxicity, which may hinder the widespread use of 225Ac for targeted alpha therapy. In this study, we describe and validate a spectrum decomposition method for dual-isotope imaging of 225Ac and 213Bi using an alpha imaging detector. We implemented an experiment to demonstrate the feasibility of using the alpha imaging detector to obtain distribution images using therapeutic amounts of 225Ac. In addition, we designed and conducted a Monte Carlo simulation under realistic conditions based on the experimental results to evaluate the spectrum decomposition method for dual-isotope imaging. The alpha imaging detector exhibited a detection efficiency of 18.5% and an energy resolution of 13.4% at 5.5 MeV. In the simulation, the distributions of 225Ac and 213Bi were obtained in each region with a relative error of 5%. The results of this study confirmed the feasibility of the dual-isotope imaging method for discriminating alpha-emitters using small amounts of 225Ac.

Complete Genome Sequence of a Sulfur-Oxidizing Bacterium, Alcaligenes faecalis Strain NLF5-7, Isolated from Livestock Wastewater.

The complete genome sequence of Alcaligenes faecalis strain NLF5-7, which was isolated from livestock wastewater, is reported. The genome of strain NLF5-7 contains genes for assimilatory sulfate reduction, dissimilatory sulfate reduction and oxidation, and an SOX system, based on its functional genetic characteristics.

Draft Genome Sequence of a Sulfur-Oxidizing Bacterium, Aquamicrobium lusatiense NLF2-7, Isolated from Livestock Wastewater.

Here, we report the draft genome sequence of Aquamicrobium lusatiense NLF2-7, a Gram-negative, aerobic, non-flagellum-forming, rod-shaped bacterium that was isolated from livestock wastewater in South Korea. The assembled genome sequence is 5,201,486 bp, with 4,972 protein-coding sequences in 12 contigs, and possess the genes for the sulfur oxidation pathway.

The microbial communities (bacteria, algae, zooplankton, and fungi) improved biofloc technology including the nitrogen-related material cycle in Litopenaeus vannamei farms.

Microbes are essential in biofloc technology for controlling nitrogen levels in water. The composition and function of microorganisms with biofloc systems were reported; however, data on microorganisms other than bacteria, such as algae (which are essential in the nitrogen cycle) and zooplankton (which are bacterial and algal predators), remain limited. The microbial communities (including bacteria, algae, zooplankton, and fungi) were investigated in shrimp farms using biofloc technology. Using Illumina MiSeq sequencing, the V4 region of 18S rRNA and the V3-V4 region of 16S rRNA were utilized for the analysis of the eukaryotic and prokaryotic microbial communities. As a result, it was found that the biofloc in the shrimp farm consisted of 48.73%-73.04% eukaryotic organisms and 26.96%-51.27% prokaryotic organisms. In these shrimp farms, prokaryotic microbial communities had higher specie richness and diversity than eukaryotic microbial communities. However, the eukaryotic microbial communities were more abundant than their prokaryotic counterparts, while algae and zooplankton dominated them. It was discovered that the structures of the microbial communities in the shrimp farms seemed to depend on the effects of predation by zooplankton and other related organisms. The results provided the nitrogen cycle in biofloc systems by the algal and bacterial groups in microbial communities.

Gene Expression Analyses of Mutant Flammulina velutipes (Enokitake Mushroom) with Clogging Phenomenon.

Regulation of proper gene expression is important for cellular and organismal survival, maintenance, and growth. Abnormal gene expression, even for a single critical gene, can thwart cellular integrity and normal physiology to cause diseases, aging, and death. Therefore, gene expression profiling serves as a powerful tool to understand the pathology of diseases and to cure them. In this study, the difference in gene expression in Flammulina velutipes was compared between the wild type (WT) mushroom and the mutant one with clogging phenomenon. Differentially expressed transcripts were screened to identify the candidate genes responsible for the mutant phenotype using the DNA microarray analysis. A total of 88 genes including 60 upregulated and 28 downregulated genes were validated using the real-time quantitative PCR analysis. In addition, proteomic differences between the WT and mutant mushroom were analyzed using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF). Interestingly, the genes identified by these genomic and proteomic analyses were involved in stress response, translation, and energy/sugar metabolism, including HSP70, elongation factor 2, and pyruvate kinase. Together, our data suggest that the aberrant expression of these genes attributes to the mutant clogging phenotype. We propose that these genes can be targeted to foster normal growth in F. velutipes.

Electronic Structure Modulation of Ag2 S by Vacancy Engineering for Efficient Bacterial Infection.

Vacancy engineering can modulate the electronic structure of the material and thus contribute to the formation of coordination unsaturated sites, which makes it easier to act on the substrate. Herein, Ag2 S and Ag2 S-100, which mainly have vacancy associates VAgS and VAgSAg , respectively, are prepared and characterized by positron annihilation spectroscopy. Both experimental and theoretical calculation results indicate that Ag2 S-100 exhibits excellent antibacterial activity due to its appropriate bandgap and stronger bacteria-binding ability, which endow it with a superior antibacterial activity compared to Ag2 S in the absence of light. The in vivo antibacterial experiment using a mouse wound-infection model further confirms that Ag2 S-100 has excellent antibacterial and wound-healing properties. This research provides clues for a deeper understanding of modulating electronic structures through vacancy engineering and develops a strategy for effective treatment of bacterial infections.

SnS Nanosheets for Rapid and Effective Bacteria Sterilization Under Near-infrared Irradiation.

Today, the threat of pathogenic bacterial infection worldwide that leads to the increase of mortality rate strongly demands the development of new antibacterial agents that can kill bacteria quickly and effectively. Although there are a lot of antibacterial agents that have been developed so far, few studies on the antibacterial performance of SnS have been investigated at 808 nm laser. Here, we synthesized SnS nanosheets with strong near-infrared absorption performance and excellent antibacterial performance via a simple solvothermal synthesis route. The as-prepared SnS nanosheets showed excellent photothermal conversion efficiency (38.7 %), photodynamic performance, and photostability, and at the same time 99.98 % and 99.7 % sterilization effect against Gram-negative Escherichia coli (E. coli) and Gram-positive Bacillus subtilis (B. subtilis) under near-infrared irradiation (808 nm, 1.5 W/cm2 ). This study suggests that SnS nanosheets could be a promising candidate for antibacterial therapy owing to the synergetic effects of photothermal and photodynamic performance.

Endophytic Fungi of Salt-Tolerant Plants: Diversity and Ability to Promote Plant Growth.

Suaeda australis, Phragmites australis, Suaeda maritima, Suaeda glauca Bunge, and Limonium tetragonum in the Seocheon salt marsh on the west coast of the Korean Penincula were sampled in order to identify the endophytes inhabiting the roots. A total of 128 endophytic fungal isolates belonging to 31 different genera were identified using the fungal internal transcribed spacer (ITS) regions and the 5.8S ribosomal RNA gene. Fusarium, Paraconiothyrium and Alternaria were the most commonly isolated genera in the plant root samples. Various diversity indicators were used to assess the diversity of the isolated fungi. Pure cultures containing each of the 128 endophytic fungi, respectively, were tested for the plant growth-promoting abilities of the fungus on Waito-C rice germinals. The culture filtrate of the isolate Lt-1-3-3 significantly increased the growth of shoots compared to the shoots treated with the control. Lt-1-3-3 culture filtrate was analyzed and showed the presence of gibberellins (GA1 2.487 ng/ml, GA3 2.592 ng/ml, GA9 3.998, and GA24 6.191 ng/ml). The culture filtrate from the Lt-1-3-3 fungal isolate produced greater amounts of GA9 and GA24 than the wild-type Gibberella fujikuroi, a fungus known to produce large amounts of gibberellins. By the molecular analysis, fungal isolate Lt-1-3-3 was identified as Gibberella intermedia, with 100% similarity.

Removal of ammonium, phosphate, and sulfonamide antibiotics using alum sludge and low-grade charcoal pellets.

Powder adsorbents perform well due to their large surface area but are difficult to use because of aggregation and channeling. In this study, pelletization of adsorbents was proposed as a solution to these operating problems. A three-component mixture was extruded into pellets and calcined under air or nitrogen conditions The pellet adsorbent removed 47, 71, 97, and 72% of ammonium, phosphate, sulfathiazole, and sulfamethoxazole, respectively. Bentonite improved greatly the strength of pellets, and a 10 wt% of bentonite was sufficient to maintain pellet shape and mass. No significant difference in individual adsorption and multi-pollutant adsorption was found. Pellet adsorbents with alum sludge, bentonite, and low-grade charcoal are low-cost materials that effectively remove multi-pollutants from the aqueous phase.

An X-ray spectrum estimation method from transmission measurement combined with scatter correction.

PURPOSE: Conventional x-ray spectrum estimation methods from transmission measurement often lead to inaccurate results when extensive x-ray scatter is present in the measured projection. This study aims to apply the weighted L1-norm scatter correction algorithm in spectrum estimation for reducing residual differences between the estimated and true spectrum. METHOD: The scatter correction algorithm is based on a simple radiographic scattering model where the intensity of scattered x-ray is directly estimated from a transmission measurement. Then, the scatter-corrected measurement is used for the spectrum estimation method that consists of deciding the weights of predefined spectra and representing the spectrum as a linear combination of the predefined spectra with the weights. The performances of the estimation method combined with scatter correction are evaluated on both simulated and experimental data. RESULTS: The results show that the estimated spectra using the scatter-corrected projection nearly match the true spectra. The normalized-root-mean-square-error and the mean energy difference between the estimated spectra and corresponding true spectra are reduced from 5.8% and 1.33 keV without the scatter correction to 3.2% and 0.73 keV with the scatter correction for both simulation and experimental data, respectively. CONCLUSIONS: The proposed method is more accurate for the acquisition of x-ray spectrum than the estimation method without scatter correction and the spectrum can be successfully estimated even the materials of the filters and their thicknesses are unknown. The proposed method has the potential to be used in several diagnostic x-ray imaging applications.

Pyrosequencing and Taxonomic Composition of the Fungal Community from Soil of Tricholoma matsutake in Gyeongju.

Tricholoma matsutake is an ectomycorrhizal fungus that has a symbiotic relationship with the root of Pinus densiflora. Soil microbial communities greatly affect the growth of T. matsutake, however, few studies have examined the characteristics of these communities. In the present study, we analyzed soil fungal communities from Gyeongju and Yeongdeok using metagenomic pyrosequencing to investigate differences in fungal species diversity, richness, and taxonomic composition between the soil under T. matsutake fruiting bodies (Sample 2) and soil where the fairy ring of T. matsutake was no longer present (Sample 1). The same spot was investigated three times at intervals of four months to observe changes in the community. In the samples from Yeongdeok, the number of valid reads was lower than that at Gyeongju. The operational taxonomic units of most Sample 2 groups were less than those of Sample 1 groups, indicating that fungal diversity was low in the T. matsutakedominant soil. The soil under the T. matsutake fruiting bodies was dominated by more than 51% T. matsutake. From fall to the following spring, the ratio of T. matsutake decreased. Basidiomycota was the dominant phylum in most samples. G-F1-2, G-F2-2, and Y-F1-2 had the genera Tricholoma, Umbelopsis, Oidiodendron, Sagenomella, Cladophialophora, and Phialocephala in common. G-F1-1, G-F2-1, and Y-F1-1 had 10 genera including Umbelopsis and Sagenomella in common. From fall to the following spring, the amount of phyla Basidiomycota and Mucoromycota gradually decreased but that of phylum Ascomycota increased. We suggest that the genus Umbelopsis is positively related to T. matsutake.

Diversity and Plant Growth Promotion of Fungal Endophytes in Five Halophytes from the Buan Salt Marsh.

The diversity and plant growth-promoting ability of fungal endophytes that are associated with five halophytic plant species (Phragmites australis, Suaeda australis, Limonium tetragonum, Suaeda glauca Bunge, and Suaeda maritima) growing in the Buan salt marsh on the west coast of South Korea have been explored. About 188 fungal strains were isolated from these plant samples' roots and were then studied with the use of the internal transcribed spacer (ITS) region (ITS1-5.8S-ITS2). The endophytic fungal strains belonged to 33 genera. Alternaria (18%) and Fusarium (12.8%), of the classes Dothideomycetes and Sordariomycetes, were most rampant in the coastal salt marsh plants. There was a higher diversity in fungal endophytes that are isolated from S. glauca Bunge than in isolates from other coastal salt marsh plants. Plant growth-promoting experiments with the use of Waito-C rice seedlings show that some of the fungal strains could encourage a more efficient growth than others. Furthermore, gibberellins (GAs) GA1, GA3, and GA9 were seen in the Sa-1-4-3 isolate (Acrostalagmus luteoalbus) culture filtrate with a gas chromatography/mass spectrometry.

Prediction of varying microcystins during non-thermal plasma oxidation of harvested microalgal biomass.

By capturing intracellular microcystins (MCs) release from microalgal cell destruction and extracellular MCs oxidation, this study suggests a mathematical model explaining the simultaneous removal of microalgae and their toxins (MC-LR, -RR, and -YR) in non-thermal plasma (NTP) application. Although the suggested model was built based on simplified kinetic assumptions, it can reasonably predict the behavior of extracellular MCs in a harvested/concentrated slurry of microalgae taken from a blooming site. After 24 h of NTP treatment, the experimental reduction of extracellular MCs was recorded up to ∼77 %. Regressions based on the experimental data reveal the degradation rate (8.60 d-1) and release rate (0.37 d-1) of MCs, which provides the essential physicochemical information about intracellular MCs release by microalgal cell destruction. Simulation results help to develop safe and useful control over the simultaneous treatment of harvested microalgal biomass and toxins. This study further demonstrates that the suggested model contributes to predicting the variation of MCs in mass management of microalgal biomass for sustainable utilization.

Diversity and Plant Growth-Promoting Effects of Fungal Endophytes Isolated from Salt-Tolerant Plants.

Fungal endophytes are symbiotic microorganisms that are often found in asymptomatic plants. This study describes the genetic diversity of the fungal endophytes isolated from the roots of plants sampled from the west coast of Korea. Five halophytic plant species, Limonium tetragonum, Suaeda australis, Suaeda maritima, Suaeda glauca Bunge, and Phragmites australis, were collected from a salt marsh in Gochang and used to isolate and identify culturable, root-associated endophytic fungi. The fungal internal transcribed spacer (ITS) region ITS1-5.8S-ITS2 was used as the DNA barcode for the classification of these specimens. In total, 156 isolates of the fungal strains were identified and categorized into 23 genera and two phyla (Ascomycota and Basidiomycota), with Dothideomycetes and Sordariomycetes as the predominant classes. The genus Alternaria accounted for the largest number of strains, followed by Cladosporium and Fusarium. The highest diversity index was obtained from the endophytic fungal group associated with the plant P. australis. Waito-C rice seedlings were treated with the fungal culture filtrates to analyze their plant growth-promoting capacity. A bioassay of the Sm-3-7-5 fungal strain isolated from S. maritima confirmed that it had the highest plant growth-promoting capacity. Molecular identification of the Sm-3-7-5 strain revealed that it belongs to Alternaria alternata and is a producer of gibberellins. These findings provided a fundamental basis for understanding the symbiotic interactions between plants and fungi.

Biosynthesis of (R)-(-)-1-Octen-3-ol in Recombinant Saccharomyces cerevisiae with Lipoxygenase-1 and Hydroperoxide Lyase Genes from Tricholoma matsutake.

Tricholoma matsutake is an ectomycorrhizal fungus, related with the host of Pinus densiflora. Most of studies on T. matsutake have focused on mycelial growth, genes and genomics, phylogenetics, symbiosis, and immune activity of this strain. T. matsutake is known for its unique fragrance in Eastern Asia. The most major component of its scent is (R)-(-)-1-octen-3-ol and is biosynthesized from the substrate linoleic acid by the sequential reaction of lipoxygenase and peroxide lyase. Here, we report for the first time the biosynthesis of (R)-(-)- 1-octen-3-ol of T. matsutake using the yeast Saccharomyces cerevisiae as a host. In this study, cDNA genes correlated with these reactions were cloned from T. matsutake, and expression studies of theses genes were carried out in the yeast Saccharomyces cerevisiae. The product of these genes expression study was carried out with Western blotting. The biosynthesis of (R)-(-)- 1-octen-3-ol of T. matsutake in recombinant Saccharomyces cerevisiae was subsequently identified with GC-MS chromatography analysis. The biosynthesis of (R)-(-)-1-octen-3-ol with S. cerevisiae represents a significant step forward.

Comamonas flocculans sp. nov., a Floc-Forming Bacterium Isolated from Livestock Wastewater.

A Gram-negative, aerobic, non-motile, rod-shaped, floc-forming, and non-spore-forming bacterium, designated as NLF-7-7T, was isolated from the biofilm of a sample collected from a livestock wastewater treatment plant in Nonsan, Republic of Korea. Strain NLF-7-7T, forms a visible floc and grows in the flocculated state. Cells of strain NLF-7-7T grew optimally at pH 6.5 and 30 °C and in the presence of 0.5% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain NLF-7-7T belonged to the family Comamonadaceae, and was most closely related to Comamonas badia DSM 17552T (95.8% similarity) and Comamonas nitrativorans 23310T (94.0% similarity). The phylogenetic and phenotypic data indicate strain NLF-7-7T is clearly distinguished from the Comamonas lineage. The major cellular fatty acids were C10:0 3OH, C16:0, and summed feature 3 (C16:1 ω6c/C16:1 ω7c). The respiratory quinone was Q-8. The polar lipids were composed of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and an unidentified aminolipid. The DNA G+C content of strain NLF-7-7 was 68.0 mol%. Based on the phenotypic, chemotaxonomic, and phylogenetic properties, strain NLF-7-7T represents a novel species of the genus Comamonas, for which the name Comamonas flocculans sp. nov. is proposed. The type strain is C. flocculans NLF-7-7T (=KCTC 62943T). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of Comamonas flocculans NLF-7-7T is MN527436. The whole-genome shotgun BioProject Number is PRJNA555370 with the Accession Number CP042344.

Unusual genome expansion and transcription suppression in ectomycorrhizal Tricholoma matsutake by insertions of transposable elements.

Genome sequencing of Tricholoma matsutake revealed its unusually large size as 189.0 Mbp, which is a consequence of extraordinarily high transposable element (TE) content. We identified that 702 genes were surrounded by TEs, and 83.2% of these genes were not transcribed at any developmental stage. This observation indicated that the insertion of TEs alters the transcription of the genes neighboring these TEs. Repeat-induced point mutation, such as C to T hypermutation with a bias over "CpG" dinucleotides, was also recognized in this genome, representing a typical defense mechanism against TEs during evolution. Many transcription factor genes were activated in both the primordia and fruiting body stages, which indicates that many regulatory processes are shared during the developmental stages. Small secreted protein genes (<300 aa) were dominantly transcribed in the hyphae, where symbiotic interactions occur with the hosts. Comparative analysis with 37 Agaricomycetes genomes revealed that IstB-like domains (PF01695) were conserved across taxonomically diverse mycorrhizal genomes, where the T. matsutake genome contained four copies of this domain. Three of the IstB-like genes were overexpressed in the hyphae. Similar to other ectomycorrhizal genomes, the CAZyme gene set was reduced in T. matsutake, including losses in the glycoside hydrolase genes. The T. matsutake genome sequence provides insight into the causes and consequences of genome size inflation.

Penicillium ulleungdoense sp. nov. from Ulleung Island in Korea.

In a study of the fungal diversity on Ulleung Island in Korea, three novel strains of Penicillium were isolated. Different sites on Ulleung Island were selected for collecting endophytic fungi, and three endophytic fungal strains showed unique morphological characteristics. DNA sequence of the internal transcribed spacer, ß-tubulin, calmodulin, and RNA polymerase II second largest subunit regions of the strains were analyzed and they showed unique taxonomic position from the other species of Penicillium section Sclerotiora. The new strains were named Penicillium ulleungdoense sp. nov. As the novel endophytic Penicillium taxa were discovered in a unique environment, the data could be meaningful for understanding the geographical distribution of Ascomycetes on Ulleung Island.

Effects of Co-culture on Improved Productivity and Bioresource for Microalgal Biomass Using the Floc-Forming Bacteria Melaminivora Jejuensis.

Bacterial and algal floc formation was induced by inoculating three species of wastewater-derived bacteria (Melaminivora jejuensis, Comamonas flocculans, and Escherichia coli) into algal cultures (Chlorella sorokiniana). Bacterial and algal flocs formed in algal cultures inoculated with M. jejuensis and C. flocculans, and these flocs showed higher sedimentation rates than pure algal culture. The floc formed by M. jejuensis (4988.46 ± 2589.81 µm) was 10-fold larger than the floc formed by C. flocculans (488.60 ± 226.22 µm), with a three-fold higher sedimentation rate (M. jejuensis, 91.08 ± 2.32% and C. flocculans, 32.55 ± 6.33%). Biomass and lipid productivity were improved with M. jejuensis inoculation [biomass, 102.25 ± 0.35 mg/(L·day) and 57.80 ± 0.20 mg/(L·day)] compared with the productivity obtained under pure algal culture conditions [biomass, 78.00 ± 3.89 mg/(L·day) and lipids, 42.26 ± 2.11 mg/(L·day)]. Furthermore, the fatty acid composition of the biomass produced under pure algal culture conditions was mainly composed of C16:0 (43.67%) and C18:2 (45.99%), whereas the fatty acid composition of the biomass produced by M. jejuensis was mainly C16:0 (31.80%), C16:1 (24.45%), C18:1 (20.23%), and C18:2 (16.11%). These results suggest the possibility of developing an efficient method for harvesting microalgae using M. jejuensis and provide information on how to improve biomass productivity using floc-forming bacteria.

Performance evaluation of a Compton SPECT imager for determining the position and distribution of 225Ac in targeted alpha therapy: A Monte Carlo simulation based phantom study.

In this study, the performance of a Compton Single Photon Emission Computed Tomography (SPECT) imager when in vivo monitoring the position and distribution of 225Ac radionuclide in targeted alpha therapy (TAT) was evaluated. When 225Ac radionuclide, which emits various γ-rays (218 and 440 keV), is used in TAT, both the photoelectric and Compton scattering events can be used for image reconstruction. Moreover, all information pertaining to the various γ-rays of the 225Ac radionuclide can be individually or simultaneously utilized in the reconstructed image. Three types of simulation phantoms and a quantitative evaluation method were used to compare the performance of the Compton SPECT imager to that of conventional SPECT imaging, which uses only photoelectric events, and the results demonstrated that the Compton SPECT imager exhibited a higher performance as the effective count for the image reconstruction was higher. To verify the accuracy of the position and distribution of the 225Ac radionuclide that had been inserted into the phantom, reconstructed images of the various γ-rays were combined with cross-sectional images of the human phantom and all combined images were found to match the predetermined simulation conditions. In conclusion, the simulation results demonstrated the feasibility of the in vivo monitoring of the position and distribution of 225Ac radionuclide using the γ-rays in TAT.