<i>Shewanella</i>-mediated synthesis of selenium nanowires and nanoribbons

Ho, Cuong Tu,Kim, Jeong Won,Kim, Won Bae,Song, Kyung,Kanaly, Robert A.,Sadowsky, Michael J.,Hur, Hor-Gil Royal Society of Chemistry 2010 Journal of materials chemistry Vol.20 No.28

<P>Amorphous selenium nanospheres, originally produced by <I>Shewanella</I> sp. strain HN-41 under anaerobic conditions, can be rapidly transformed into extensive, long and thin, polycrystalline Se nanowires and nanoribbons (>100 μm × 57 nm) in 80% DMSO with bacterial pellets at physiological temperature. Scanning and transmission electron microscopic analyses indicated that the Se nanowires and nanospheres were crystalline structures indexed into the hexagonal plane of Se. The structures possessed an unusually high crystalline peak (100), suggesting a preferential [001] growth direction. Electron micrographic analyses and incubation studies suggested that the cell membrane of the <I>Shewanella</I> sp. strain HN-41 likely plays an important role in the formation of amorphous Se nanospheres from soluble Se(<SMALL>IV</SMALL>) and the formation of long and thin <I>h</I>-Se nanowires and nanoribbons. The formation of zero- and one-dimensional <I>h</I>-Se nanostructures by this bacterium may provide a facile strategy to recover soluble Se(<SMALL>IV</SMALL>) from the environment and generate new materials that will be useful for advanced nanotechnologies.</P> <P>Graphic Abstract</P><P><I>Shewanella</I>-induced Se nanowires and nanoribbons formed from biogenic amorphous Se nanospheres in 80% DMSO. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b923252d'> </P>

Enzymatic Properties of Atrazine Chlorohydrolase Entrapped in Biomimetic Silica

Cuong Tu Ho,Suil Kang,Hor Gil Hur 한국응용생명화학회 2008 Journal of Applied Biological Chemistry (J. Appl. Vol.51 No.4

Seasonal Change of Sediment Microbial Communities and Methane Emission in Young and Old Mangrove Forests in Xuan Thuy National Park

( Cuong Tu Ho ),( Unno Tatsuya ),( Son Giang Nguyen ),( Thi-hanh Nguyen ),( Son Truong Dinh ),( Son Tho Le ),( Thi-minh-hanh Pham ) 한국미생물생명공학회 2024 Journal of microbiology and biotechnology Vol.34 No.3

Microbial communities in mangrove forests have recently been intensively investigated to explain the ecosystem function of mangroves. In this study, the soil microbial communities under young (< 11 years-old) and old ( >17 years-old) mangroves have been studied during dry and wet seasons. In addition, biogeochemical properties of sediments and methane emission from the two different mangrove ages were measured. The results showed that young and old mangrove soil microbial communities were significantly different on both seasons. Seasons seem to affect microbial communities more than the mangrove age does. Proteobacteria and Chloroflexi were two top abundant phyla showing >15%. Physio-chemical properties of sediment samples showed no significant difference between mangrove ages, seasons, nor depth levels, except for TOC showing significant difference between the two seasons. The methane emission rates from the mangroves varied depending on seasons and ages of the mangrove. However, this did not show significant correlation with the microbial community shifts, suggesting that abundance of methanogens was not the driving factor for mangrove soil microbial communities.

Growth Mechanism of Amorphous Selenium Nanoparticles Synthesized by <i>Shewanella</i> sp. HN-41

TAM, Kawai,HO, Cuong Tu,LEE, Ji-Hoon,LAI, Min,CHANG, Chong Hyun,RHEEM, Youngwoo,CHEN, Wilfred,HUR, Hor-Gil,MYUNG, Nosang V. Japan Society for Bioscience, Biotechnology, and A 2010 Bioscience, Biotechnology, and Biochemistry Vol.74 No.4

<P><I>Shewanella</I> sp. HN-41 was exploited for selenium nanoparticles synthesis from aqueous selenite compounds under anaerobic conditions. Various reaction conditions, including reaction time, initial biomass, and initial selenite concentration, were systematically investigated to determine their effects on particle size distribution and formation rate. The biomass concentration of <I>Shewanella</I> sp. HN-41 had no significant effect on average particle size but strongly influenced reduction rate and size distribution. Initial selenite concentration (0.01–1.0 m<SMALL>M</SMALL>) also had no significant effect on the average particle size, but affected the early growth stage mechanism of selenium particle production, which was modeled using a Michaelis Menten model. The HR-TEM and SAED patterns indicated that the synthesized selenium nanoparticles were amorphous.</P>

Copper Tolerance of Novel Rhodotorula sp. Yeast Isolated from Gold Mining Ore in Gia Lai, Vietnam

Kim Cuc Thi Nguyen,Phuc Hung Truong,Cuong Tu Ho,Cong Tuan Le,Khoa Dang Tran,Tien Long Nguyen,Manh Tuan Nguyen,Phu Van Nguyen 한국균학회 2023 Mycobiology Vol.51 No.6

In this study, twenty-five yeast strains were isolated from soil samples collected in the goldmining ore in Gia Lai, Vietnam. Among them, one isolate named GL1T could highly tolerateCu2þ up to 10 mM, and the isolates could also grow in a wide range of pH (3–7), and temperature(10–40 �C). Dried biomass of GL1 was able to remove Cu2þ effectively up to 90.49%with a maximal biosorption capacity of 18.1 mg/g at pH 6, temperature 30 �C, and incubationtime 60 min. Sequence analysis of rDNA indicated this strain was closely related toRhodotorula mucilaginosa but with 1.53 and 3.46% nucleotide differences in the D1/D2domain of the 28S rRNA gene and the ITS1-5.8S rRNA gene-ITS2 region sequence, respectively. Based on phylogenetic tree analysis and the biochemical characteristics, the strainappears to be a novel Rhodotorula species, and the name Rhodotorula aurum sp. nov. is proposed. This study provides us with more information about heavy metal-tolerant yeasts andit may produce a new tool for environmental control and metal recovery operations.

Metagenomic investigation of the seasonal distribution of bacterial community and antibiotic‑resistant genes in Day River Downstream, Ninh Binh, Vietnam

Nguyen Son Giang,Raza Shahbaz,Ta Loan Thi,Le Lan-Anh Thi,Ho Cuong Tu,Unno Tatsuya 한국응용생명화학회 2022 Applied Biological Chemistry (Appl Biol Chem) Vol.65 No.2

In this study, we use high-throughput sequencing-based metagenomic methods to investigate the differences in seasonal structures of the bacterial community and the abundance and diversity of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in both shrimp ponds and river water samples downstream of the Day River, Ninh Binh, Vietnam. The structure of the central bacterial community, ARGs, and MGEs was found to be regardless of the seasons and locations. The predominant phyla found in all samples was Proteobacteria, Bacteroidetes, and Actinobacteria. Multi-drug resistance (MDR) genes and transposases are the most dominant ARG types and MGEs, respectively. Our data showed a higher abundance of bacterial communities, ARGs, and MGEs in the river water during the rainy season. There is a significant correlation between the abundance of ARGs, MGEs, and environmental factors. Our results indicate that water environments containing ARGs/MGEs carrying bacteria pose a risk to shrimp and human health, especially during the rainfall-polluted water season.

Metagenomics analysis of methane metabolisms in manure fertilized paddy soil

응우옌 기앙 손,호 투 궝,이지훈,운노타쯔야,Nguyen, Son G.,Ho, Cuong Tu,Lee, Ji-Hoon,Unno, Tatsuya The Microbiological Society of Korea 2016 미생물학회지 Vol.52 No.2

Under flooded rice fields, methanogens produce methane which comes out through rice stalks, thus rice fields are known as one of the anthropogenic sources of atmospheric methane. Studies have shown that use of manure increases amount of methane emission from rice. To investigate mechanisms by which manure boosts methane emission, comparative soil metagenomics between inorganically (NPK) and pig manure fertilized paddy soils (PIG) were conducted. Results from taxonomy analysis showed that more abundant methanogens, methanotrophs, methylotrophs, and acetogens were found in PIG than in NPK. In addition, BLAST results indicated more abundant carbohydrate mabolisetm functional genes in PIG. Among the methane metabolism related genes, PIG sample showed higher abundance of methyl-coenzyme M reductase (mcrB/mcrD/mcrG) and trimethylamine-corrinoid protein Co-methyltransferase (mttB) genes. In contrast, genes that down regulate methane emission, such as trimethylamine monooxygenase (tmm) and phosphoserine/homoserine phosphotransferase (thrH), were observed more in NPK sample. In addition, more methanotrophic genes (pmoB/amoB/mxaJ), were found more abundant in PIG sample. Identifying key genes related to methane emission and methane oxidation may provide fundamental information regarding to mechanisms by which use of manure boosts methane emission from rice. The study presented here characterized molecular variation in rice paddy, introduced by the use of pig manure. 침수된 논토양에서는 메탄생성균이 벼 줄기를 타고 올라오는 메탄을 생성하는 것으로 알려져 있고, 그래서 논토양은 대기 메탄의 인위적인 발생원 중 하나로 알려져 있다. 또한 (분뇨)거름을 사용하면 벼로부터 메탄 배출이 증가하는 것으로 연구 결과 알려져 있다. 어떠한 기작으로 (분뇨)거름이 메탄 배출을 증가시키는지 알아보기 위하여, 무기비료를 사용한 논토양(NPK)과 돈분뇨를 처리한 논토양(PIG)에서의 미생물의 메타게놈에 대해 비교분석을 수행하였다. 미생물군집 분류 분석 결과, 메탄생성균과 메탄영양균, 메틸영양균, 초산생성균(acetogen)이 NPK에서 보다 PIG에서 더 풍부하였다. 더욱이 BLAST 비교 분석 결과 탄수화물 대사 기능유전자가 PIG에 더 풍부하였다. 메탄 대사와 관련된 유전자 중에서 메틸-조효소-M-환원효소(mcrB/mcrD/mcrG)와 트리메틸아민-코리노이드 단백질 Co-메틸전달효소(mttB)가 PIG 시료에 더 풍부하였다. 그와는 상대적으로, 트리메틸아민 모노산소첨가효소(tmm)와 포스포세린/호모세린 인산전달효소(thrH) 같은 메탄 배출을 하향 조절하는 유전자는 NPK 시료에서 더 관찰되었다. 메탄영양과 관련된 유전자(pmoB/amoB/mxaJ)들 또한 PIG에서 더 풍부하게 발견되었다. 메탄 배출과 메탄 산화와 관련된 핵심 유전자들을 환경에서 확인함으로써, (분뇨)거름 사용에 의해 벼로부터 메탄 배출이 증가하는 기작에 대해 기초적인 정보를 얻을 수 있을 것이다. 본 연구에 제시된 내용을 통해 돈분료거름을 처리한 논토양 내 미생물의 분자적 변이를 알 수 있었다.