• Journal of Microbiology and Biotechnology
• /
• 제17권2호
• /
• pp.226-233
• /
• 2007

Members of Methylobacterium, referred as pink-pigmented facultative methylotrophic bacteria, are frequently associated with terrestrial and aquatic plants, tending to form aggregates on the phyllosphere. We report here that the production of autoinducer molecules involved in the cell-to-cell signaling process, which is known as quorum sensing, is common among Methylobacterium species. Several strains of Methylobacterium were tested for their ability to produce N-acyl-homoserine lactone (AHL) signal molecules using different indicators. Most strains of Methylobacterium tested could elicit a positive response in Agrobacterium tumefaciens harboring lacZ fused to a gene that is regulated by autoinduction. The synthesis of these compounds was cell-density dependent, and the maximal activity was reached during the late exponential to stationary phases. The bacterial extracts were separated by thin-layer chromatography and bioassayed with A. tumefaciens NTI (traR, tra::lacZ749). They revealed the production of various patterns of the signal molecules, which are strain dependent. At least two signal molecules could be detected in most of the strains tested, and comparison of their relative mobilities suggested that they are homologs of N-octanoyl-$_{DL}$-homoserine lactone ($C_8-HSL$) and N-decanoyl-$_{DL}$-homoserine lactone ($C_{10}-HSL$).

• 치위생과학회지
• /
• 제3권1호
• /
• pp.11-14
• /
• 2003

각종 토양시료로부터 M배지와 AMP배지에서 생육하는 500여종의 방선균을 분리하였으며, 그 중 전배양배지(GMY 배지)에서 가장 뛰어난 항암활성능을 소유한 균주를 불리하고 배양하여 세포외 항암성물질을 분리하여 이 물질을 완전정제하고 MTT 정량분석을 실시하여 암세포에 대한 세포독성검사를 실시하였다. 1. 정제는 배양한 균체를 완전히 제거하고 동량의 ethylacetate를 처리하여 배양액중의 항암성분을 추출하고 무수 magnesium sulfate로 건조 후 농축, ethanol로 용해, 10배량의 water을 첨가하여 $4^{\circ}C$에서 overnight 시킨 후 추출액을 원심분리(12,000 rpm, 30분)하여 methylene chloride로 용해시켜 silica gel 60 column(${\phi}35{\times}600mm$, Merck Co.), methylene chloride-ethanol(96:4) 용매로 용출하고 sephadex LH-20 column(${\phi}15{\times}300mm$, Pharmacia LKB)에서 100% methanol로 용출하여 HPLC(Waters, ODS)를 이용하여 최종적으로 완전 정제하였다. 2. Compound는 Gram(+) 세균(6균주), Gram(-) 세균(11균주), 효모(2균주), 곰팡이(1균주)에 대하여 항균 효과를 나타내었다. 3. 완전 정제된 물질에 대한 항암효과를 측정한 결과, 모든 실험 암세포에 대해서 뛰어난 항암효과를 나타내었으며 protein성 물질은 아닌 것으로 추정되었다.

• Journal of Microbiology and Biotechnology
• /
• 제19권1호
• /
• pp.17-22
• /
• 2009

The mixotrophic growth with methanol plus thiosulfate was examined in nutrient-limited mixotrophic condition for Methylobacterium goesingense CBMB5 and Methylobacterium fujisawaense CBMB37. Thiosulfate oxidation increased the growth and protein yield in mixotrophic medium that contained 150mM methanol and 20mM sodium thiosulfate, at 144 h. Respirometric study revealed that thiosulfate was the most preferable reduced inorganic sulfur source, followed by sulfite and sulfur. M. goesingense CBMB5 and M. fujisawaense CBMB37 oxidized thiosulfate directly to sulfate, and intermediate products of thiosulfate oxidation such as polythionates, sulfite, and sulfur were not detected in spent medium and they did not yield positive amplification for tested soxB primers. Enzymes of thiosulfate oxidation such as rhodanese and sulfite oxidase activities were detected in cell-free extracts of M. goesingense CBMB5, and M. fujisawaense CBMB37, and thiosulfate oxidase (tetrathionate synthase) activity was not observed. It indicated that both the organisms use the "non-S4 intermediate" sulfur oxidation pathway for thiosulfate oxidation. It is concluded from this study that M. goesingense CBMB5, and M. fujisawaense CBMB37 exhibited mixotrophic metabolism in medium containing methanol plus thiosulfate and that thiosulfate oxidation and the presence of a "Paracoccus sulfur oxidation" (PSO) pathway in methylotrophic bacteria are species dependant.

• Molecules and Cells
• /
• 제23권3호
• /
• pp.370-378
• /
• 2007

A superoxide dismutase was purified 62-fold in seven steps to homogeneity from Methylobacillus sp. strain SK1, an obligate methanol-oxidizing bacterium, with a yield of 9.6%. The final specific activity was 4,831 units per milligram protein as determined by an assay based on a 50% decrease in the rate of cytochrome c reduction. The molecular weight of the native enzyme was estimated to be 44,000. Sodium dodecyl sulfate gel electrophoresis revealed two identical subunits of molecular weight 23,100. The isoelectric point of the purified enzyme was found to be 4.4. Maximum activity of the enzyme was measured at pH 8. The enzyme was stable at pH range from 6 to 8 and at high temperature. The enzyme showed an absorption peak at 280 nm with a shoulder at 292 nm. Hydrogen peroxide and sodium azide, but not sodium cyanide, was found to inhibit the purified enzyme. The enzyme activity in cell-free extracts prepared from cells grown in manganese-rich medium, however, was not inhibited by hydrogen peroxide but inhibited by sodium azide. The activity in cell extracts from cells grown in iron-rich medium was found to be highly sensitive to hydrogen peroxide and sodium azide. One mol of native enzyme was found to contain 1.1 g-atom of iron and 0.7 g-atom of manganese. The N-terminal amino acid sequence of the purified enzyme was Ala-Tyr-Thr-Leu-Pro-Pro-Leu-Asn-Tyr-Ala-Tyr. The superoxide dismutase of Methylobacillus sp. strain SK1 was found to have antigenic sites identical to those of Methylobacillus glycogenes enzyme. The enzyme, however, shared no antigenic sites with Mycobacterium sp. strain JC1, Methylovorus sp. strain SS1, Methylobacterium sp. strain SY1, and Methylosinus trichosproium enzymes.

• 한국토양비료학회지
• /
• 제43권4호
• /
• pp.506-513
• /
• 2010

다양한 유기질비료 수준에서 Methylobacterium oryzae CBMB20의 처리가 고추의 생육촉진에 미치는 영향을 조사하였다. 유기질비료 권장시비수준의 70, 85, 100, 120% 시용구에서 시비량이 증가함에 따라 고추의 신장, 건물중 및 수량에서 유의성 있는 증가를 확인하였다. M. oryzae CBMB20의 접종 처리에서 고추의 생장이 증가하였으며, 고추의 수량 또한 각 유기질 비료 수준별로 10~35% 증가하였다. 수확기에 조사한 근권토양의 메탄올자화세균의 밀도는 M. oryzae CBMB20 처리구에서 2.51~2.63 log CFU $g^{-1}$ soil 이었으며, 미처리구에서는 1.0 log CFU $g^{-1}$ soil 이하로 나타났다. 따라서 접종한 M. oryzae CBMB20은 고추 작물 근권토양에 효과적으로 군집하였으며, 식물생장촉진 호르몬의 분비 등의 작용을 통한 작물생장촉진효과를 발휘한 것으로 판단된다. M. oryzae CBMB20을 접종하지 않은 경우에는 고추의 최대 생장과 수량이 유기질 비료 권장시비 수준 120%에서 나타났으나, M. oryzae CBMB20을 접종한 경우에는 최대 생장과 수량이 권장시비 수준에서 나타났다. 이러한 결과는 식물생장촉진미생물의 접종을 통하여 비료 사용량의 절감 가능성을 제시하는 것이며, 식물생장 촉진 미생물 제제로서 M. oryzae CBMB20의 활용이 가능하리라 사료된다.