Proceedings of the Microbiological Society of Korea Conference (한국미생물학회:학술대회논문집)
The Microbiological Society of Korea
- Annual
Domain
- Life Science > Molecular Cell Biology
2003.05a
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Studies on marine microbial diversity using direct analysis of rRNA sequences have revealed previously unrecognized microbes and novel phylogenetic lineages that represent major components of global microbial assemblages. This diversity in the marine biosphere offers opportunities for research and application in the field of biotechnology; global gas exchange, nutrient and element cycling, biomass md food production, marine bioproducts, and bioprocesses. Especially, deep-sea encompasses the extremes of virtually at] environmental parameters found on Earth and provides extreme microorganisms. In this study several extreme microorganisms were successfully isolated from the deep-sea sediment samples obtained by joining ocean cruises for last 2 years and some of them will be introduced.
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Lichen is one of the most widely distributed eucaryotic organisms in the world. Lichen is the result of a symbiotic association between two unrelated organisms - a fungus and an alga (or cyanobacterium). Researches in Korean lichens were mainly focused on investigation of Korean lichen flora and most of them were primitive and short-term based projects until 1990's. In this communication, current status and prospect of Korean lichen research are briefly discussed with emphasis of KoLRI (Korean Lichen Research Institute) activities and roles in national research projects on bioresource development in Korea.
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Heo Gun-Young;Park Jeong A;Oh Yun Jung;Lee Jung Sook;Kim Chi Kyung;Mheen Tae Ick;Ahn Jong Seog 22
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We isolated and identifed culturable Arctic bacteria that have inhabited around Korean Arctic Research Station Dasan located at Ny-Alsund, Svalbard, Norway
$(79^{\circ}N,\;12^{\circ}E)$ . The pure colonies were inoculated into nutrient liquid media, genomic DNA was extracted, and phylogenetic analysis was performed on the basis of 16S rDNA sequences. Out of total 227 strains, 198 strains were overlapped or unidentified, and 43 bacteria were finally identified: 31 strains belonged to Pseudomonas, 7 strains Arthrobacter, two Flavobacterium sp., an Achromobacter sp., a Pedobacter sp., and a Psychrobacter sp. For isolation of diverse bacteria, we need more effective transport method than 3M petri-films, which were used for convenience of transportation that was restricted by volume. We also need to use other culture media than nutrient media. We expect these Arctic bacteria can be used for screening to develop new antibiotics or industrial enzymes that are active at low temperature. -
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Analysis of the Neurospora crassa genome data reveals at least 14 proteins that contain tetratricopeptide repeat (TPR) motifs. One of them shows over
$60\%$ homology with SSN6 of Saccharomyces cerevisiae, a global repressor that mediates repression of genes involved in various cellular processes. Sequence analysis of its cDNA shows that it encodes a putative 102kDa protein. Mutant strains generated by RIP (repeat induced point mutation) process show four distinctive patterns of vegetative growth at various rates. They are male-fertile, yet all female-sterile and produced little or no perithecium. These results indicate that this gene is pleiotropic and involved in several cellular processes of vegetative growth, conidiation and sexual cycle. It is designated rcm-1(regulation of conidiation and morphology). -
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Current therapeutic strategies far anthrax have had no significant impact on anthrax mortality over the last several decades. This study used a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) discovery platform to generate protein expression profiles in search of overexpressed proteins in murine macrophage cells (RAW264.7) which infected with Bacillus anthracis spores as potentially novel molecular targets. Two differentially expressed proteins were identified in infected murine macrophage cells as Syndapin and CDC46, respectively. Syndapins are potential links between the cortical actin cytoskeleton and endocytosis. Other two proteins were identified from murine macrophage cells infected with avirulent spores as ITBG-2 (CD18) and HSPA5, respectively. These data demonstrate the feasibility of using a MALDI-TOF platform to generate protein expression profiles and identify potential molecular targets for anthrax therapeutics.
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Major advances in positive-sense RNA virus research have been facilitated by the development of reverse genetics systems. These systems consist of an infectious cDNA clone that encompasses the genome of the virus in question. This clone is then used as a template for the subsequent synthesis of infectious RNA for the generation of synthetic viruses. However, the construction of infectious cDNA for the Japanese encephalitis virus (JEV) has been repeatedly thwarted by the instability of its cDNA. As JEV is an important human pathogen that causes permanent neuropsychiatric sequelae and even fatal disease, a reliable reverse genetics system for this virus is highly desirable. The availability of this tool would greatly and the development of effective vaccines as well as facilitate studies into the basic biology of the virus, including the molecular mechanisms of viral replication, neurovirulence, and pathogenesis. We have successfully constructed a genetically stable infectious JEV cDNA containing full-length viral RNA genome. Synthetic RNA transcripts generated in vitro from the cDNA were highly infectious upon transfection into susceptible cells, and the cDNA remained stable after it had been propagated in E. coli for 180 generations. Using this infectious JEV cDNA, we have successfully expressed a variety of reporter genes from the full-length genomic and various subgenomic RNAs in vitro transcribed from functional JEV cDNAS. In summary, we have developed a reverse genetics system for JEV that will greatly facilitate the research on this virus in a variety of different fields. It will also be useful as a heterologous gene expression vector and aid the development of a vaccine against JEV.
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The dynamics of microbial community structure of the various domestic wastewater treatment processes were examined using a novel approach of quinone profiles. The compositions of microbial quinone of 5 sites fer plant and lab-scale activated sludge were analyzed. More than 14 kinds of quinones were observed in the activated sludges tested in this study. The microbial community structure of the plant activated sludge processes a little differed from that of the lab-scale submerged MBR systems. The dominant quinones were UQ-8, UQ-10 followed
$MK-8(H_4)$ , MK-7 and MK-6. The molar ratio of ubiquinones to menaquinones (UQ/MK) changed from 0.81 to 1.9, indicating that aerobic bacteria dominated the microbial community of the activated sludge examined. The microbial diversity of the activated sludges calculated from the all quinone compositions was 9.5-11.9 and the microbial equability of the activated sludges was 0.64-0.79. -
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A method for detection and quantification of aceticlastic methanogens using a real-time PCR with a TaqMan probe was developed. Two sets of primers and probes targeting the family Methanosarcinaceae and Methanosaetaceae were designed by using the Ribosormal Database Project (RDP) II, and softwares for phylogenetic probe design and sequence analysis. Target-group specificity of each set of primers and probe was verified by testing DNAs isolated from pure cultures of 28 archaeal strains purchased from DSMZ. Cell numbers in the 28 archaeal cultures and in the samples from anaerobic processes were quantified using a real-time PCR with the sets of primers and probe. In conclusion, the real-time PCR assay was very specific for the corresponding target methanogenic family and was proved to be a powerful method for quantification of aceticlastic methanogens in anaerobic processes.
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Cyclodextrin glucanotransferase (CGTase) and endoxylanase genes of Bacillus sp. were subcloned down-stream of yeast ADH1 promoter and expressed in S. cerevisiae. Most of the CGTase and endoxylanase expressed were detected in the extracellular medium with activity of 0.6 and 7-8 unit/ml, respectively. The recombinant enzymes were secreted as N-linked-glycosylated forms, resulting an enhanced thermal stability. CGTase predominantly produced
$\alpha-cyclodextrin$ from starch and endoxylanase produced xylobiose and xylotriose from xylan. -
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