• Journal of Microbiology and Biotechnology
• /
• 제11권6호
• /
• pp.940-945
• /
• 2001

Symbiobacterium toebii has been previously reported as a novel commensal thermophile exhibiting a commensal interaction with thermophilic Geobacillus sp. SK-1. We investigated the distribution of this commensal thermophile in various soils using molecular methods, such as quantitative PCR and terminal restriction fragment polymorphism analysis. Based on a nested competitive quantitative PCR the 16S rDNA of the commensal thermophile was only detected in compost soils at about $1.0{\times}10^4$ cpoies per gram of soil, corresponding to $0.25{\times}10^4$ cells per gram of soil. However, in an enrichment experiment at $60^{\circ}C$, about $1.0{\times}10^8$ copies of 16S rDNA molecules were detected per ml of enriched culture broth for all the soils, and more than 0.1 mM indole accumulated as the product of commensal bacterial growth. When incubated at $30^{\circ}C$, neither the 16S rDNA of the commensal bacterium nor any indole accumulation was detected. Accordingly, even though the 16S rDNA of the bacterium was only detected in the compost soils by a nested PCR, the presence of the 16S rDNA molecules of commensal thermophile and accumulation of indole in all the enriched cultures appeared to indicate that the commensal thermophile is widely distributed in various soils.

• Journal of Microbiology and Biotechnology
• /
• 제19권12호
• /
• pp.1497-1505
• /
• 2009

The thermophile Bacillus fordii MH602 was screened for stereospecifically hydrolyzing DL-5-substituted hydantoins to L-$\alpha$-amino acids. Since the reaction occurs at higher temperature, the advantages for enhancement of substrate solubility and for racemization of DL-5-substituted hydantoins during the conversion were achieved. The hydantoin metabolism gene cluster from thermophile is firstly reported in this paper. The genes involved in hydantoin utilization (hyu) were isolated on an 8.2-kb DNA fragment by restriction site-dependent PCR, and six ORFs were identified by DNA sequence analysis. The hyu gene cluster contained four genes with novel cluster organization characteristics: the hydantoinase gene hyuH, putative transport protein gene hyuP, hyperprotein gene hyuHP, and L-carbamoylase gene hyuC. The hyuH and hyuC genes were heterogeneously expressed in E. coli. The results indicated that hyuH and hyuC are involved in the conversion of DL-5-substituted hydantoins to an N-carbamyl intermediate that is subsequently converted to L-$\alpha$-amino acids. Hydantoinase and carbamoylase from B. fordii MH602 compared respectively with reported hydantoinase and carbamoylase showed the highest identities of 71% and 39%. The novel cluster organization characteristics and the difference of the key enzymes between thermopile B. fordii MH602 and other mesophiles were presumed to be related to the evolutionary origins of concerned metabolism.

• 농업과학연구
• /
• 제7권1호
• /
• pp.44-51
• /
• 1980

고온균(高溫菌) tryptophanase을 분리하기 위하여 tryptophan이 함유된 액체배지에 화산토양(火山土壤), 온천수(溫泉水)를 비롯한 각 지역의 토양(土壤)과 퇴비(堆肥) 등의 분리원(分離源)을 접종(接種)하고 $60^{\circ}C$에서 집적배양(集積培養)한 결과 indole 생성원수(生成園數)의 변화는 다음과 같다. 집적배양(集積培養) 중에 Penicilin G 10r와 Chloramphenicol 10r의 첨가로 집적배양액(集積培養液) ml 당(當) indole 생성원(生成園)의 수(數)는 $10^3cells/ml$, $10^7cells/ml$으로 농축(濃縮)이 가능하였다. indole 생성원(生成園)은 고체배지상에 생육이 되지 아니하였음으로 순수분리(純粹分離)를 위하여서는 액체배지를 이용한 분리 방법 등의 검토가 요망되었다.

• 한국균학회지
• /
• 제15권3호
• /
• pp.187-195
• /
• 1987

두가지 열처리법에 의한 균 분리방법을 사용하여, 보통균을 제외한 토양균의 분리와 그의 논토양중의 수직 및 계절별 분포를 파악하기 위하여 역곡동과 신원동의 논토양을 시료로 사용하였다. $42^{\circ}C$에서 2일간 배양후 $37^{\circ}C$로 배양하는 방법과 $70^{\circ}C$에서 15분간 열처리하는 방법을 사용하였다. $42^{\circ}C$ 배양법에서는 두 장소에서 분리된 토양균은 거의가 mesophile이었으며 thermotolerant fungi는 Asergillus fumigatus, thermophile로는 Sporotrichum thermophile과 Malbranchea pulchella var. sulfrea이었고, 이들 중 우점종은 Asergillus fumigatus이었다. 두 장소에서 9속, 14종이 분리동정되었으며 Sporotrichum thermophile, Talaromyces ucrainicus, Malbranchea pulchella var. sulfrea는 한국 미기록 종이다. $72^{\circ}C$ 열처리방법으로 분리한 경우 두 장소에서 10속, 20종이 분리동정되었으며, 분리된 균은 거의가 mesophile이었으며 thermotolerant fungi는 Asergillus fumigatus이었고, 우점종은 Talaromyces stipitatus이었다. 또한 Talaromyces helicus var. major, Emericella nidulans var. nidulans, Chaetomium subspirale, Neosartorya fishiri var. fischeri는 한국 미기록 종이다. 두가지 분리방법으로 분리된 토양균의 계절적 분포는 여름과 봄이 가을과 겨울보다 높았으며, 전체 균의 수와 우점종 균수, 그리고 나타나는 종의 빈도는 그 수직분포에 있어서 상층에서 가장 높았으나 하층으로 내려갈수록 감소하였다.

• 한국생물정보학회:학술대회논문집
• /
• 한국생물정보시스템생물학회 2002년도 제2차워크샵
• /
• pp.111-123
• /
• 2002

• 한국미생물생명공학회:학술대회논문집
• /
• 한국미생물생명공학회 2001년도 Proceedings of 2001 International Symposium
• /
• pp.133-134
• /
• 2001

• 한국유전체학회:학술대회논문집
• /
• 한국유전체학회 2003년도 The 12th Korea Genome Conference
• /
• pp.45.2-45.2
• /
• 2003

• BMB Reports
• /
• 제34권4호
• /
• pp.347-354
• /
• 2001

$\alpha$-Glucosidase of an extreme thermophile, Thermus caldophilus GK24 (TcaAG), was purified 80-fold from cells to a homogeneous state and characterized. The enzyme exhibited optimum activity at pH 6.5 and $90^{\circ}C$, and was stable from pH 6.0 to 85 and up to $90^{\circ}C$. The enzyme had a half-life of 85 minutes at $90^{\circ}C$. An analysis of the substrate specificity showed that the enzyme hydrolyzed the non-reducing terminal unit of $\alpha$-1,6-glucosidic linkages of isomaltosaccharides and panose, $\alpha$-1,3-glycosidic bond of nigerose and turanose, and $\alpha$-1,2-glycosidic bond of sucrose. The gene encoding the TcaAG was cloned, sequenced, and sequenced in E. coli. The nucleotide sequence of the gene encoded a 530 amino acid polypeptide and had a G+C content of 68.4% with a strong bias for G or C in the third position of the codons (93.6%). A sequence analysis revealed that TcaAG belonged to the $\alpha$-amylase family. We suggest that this monomeric, thermostable, and broad-acting $\alpha$-glucosidase is a departure from previously exhibited specificities. It is, therefore, a novel $\alpha$-glucosidase.

• Journal of Microbiology and Biotechnology
• /
• 제14권2호
• /
• pp.312-316
• /
• 2004

Five strains, producing bacterial thermostable L-arabinose isomerase, were isolated from Korean soil samples obtained from compost under high temperature circumstances. Among these strains, the CBG-Al showed the highest L-arabinose isomerase activity at $60^\circ{C}$ and was selected as a D-tagatose producing strain from D-galactose. This strain was identified as Geobacillus thermodenitrificans based on the 16S rRNA analysis, and biological and biochemical characteristics. The isolated strain was aerobic, rod-shaped, Gram-positive, nonmotile, and an endospore-forming bacterium. No growth was detected in culture temperature below $40^\circ{C}$. The maximum growth temperature and maximum temperature of enzyme activity were $75^\circ{C}$ and $65^\circ{C}$, respectively. In metal ion effects, $Ca^{2+}$ was the most effective enzyme activator with the reaction rate by 150%. In a 5-1 jar fermentor with 3-1 MY medium, L-arabinose isomerase activity was growth-associated and pH decreased rapidly after the initial logarithmic phase.

• 한국미생물·생명공학회지
• /
• 제16권5호
• /
• pp.393-397
• /
• 1988

고도 호열성균의 Adenylate kinase가 phospho cellulose column의 adenosine-penta-phospho adenosine affinity elution으로부터 균일하게 정제되었다. 분자량은 SDS PAGE와 gel filtration으로부터 22,000의 단량체로 밝혀졌다. 효소반응의 최적온도는 8$0^{\circ}C$이였으며 정반응의 활성화 에너지는 22.4kcal/mole이었다. 본 효소는 6M guanidine-HCI에 활성을 잃지 않았으며 10$0^{\circ}C$에서 한시간에 75%의 활성을 유지하였다. AMP, ADP, ATP에 대한 Km치는 0.01mM, 0.017mM, 0.067mM이었다.