Journal of Microbiology

Phosphatase activity in Cheonho Reservoir: Kwag, No Tae , Son, Jae Hak , Lee, Jeong Sub , Ahn, Tae Young; J. Microbiol. 1995;33(4):267-272.

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Abstract: Phosphatase activity was measured with other environmental factors in Cheonho reservoir in 1994. It ranged form 95 to 1,685 nM/1/h and was correlated significantly with chlorophyll-a. Such a close relation well matched the fact that over 90% of phosphatase activity was detected in > 3 um fraction. The phosphatase activity also correlated negatively with dissolved inorganic phosphate concentration, which implies derepression of phosphatase production by phosphate limitation. Significant correlation was analyzed between phosphatase activity and BOD, which also appeared to be closely correlated with chlorophyll-a. A great percentage of organic materials seems to be generated autochthonously by algae and extracellular enzyme even though allochthonous influence was thought to be stronger in Cheonho reservoir.

Identification of intestinal microflora in rainbow trout: Lee, Soon Deuk , Lee, Yeon Hee; J. Microbiol. 1995;33(4):273-277.

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Abstract: Although trout farming is well established in Korea, very little information is available on the composition of intestinal microflora in rainbow trout (Salmo gairdnerii). In 1994, from October through November, we investigated the composition and succession of intestinal bacteria. As fish grew, total viable counts increased dramatically until 45 days after fertilization when anaerobes started to appear on the media. After this time, they increased steadily. Ten aerobic generic were identified and Gram negative bacteria constituted 85% of total isolates. Among these, Pseudomonas, Eikenella, and Alcaligenes were the three major genera. Six anaerobic genera were isolated and identified. The ratio of anaerobes to aerobes was about 1 : 1 in adult trout and the composition of genera was changed under different conditions.

Adsorption of Pb^2+ in the components of bacterial cell membrane: Kim , Mal Nam; J. Microbiol. 1995;33(4):278-282.

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Abstract: S. epidermidis cell was fractionated into cell wall, cell membrane and cytoplasm. The cell membrane adsorbed the most abundant Pb^2+ per unit dry weight of the three fractions tested. Adsorption behavior of Pb^2+ in lipid and protein, which are the main components of the cell membrane, indicated that phosphatidylethanolamine and phosphatidylinositol having phosphoryl group and gangliosides containing carboxyl groups adsorbed much more Pb^2+ than triglycerides lacking any chargeable functional groups. Protein purified from cell membrane adsorbed larger amount of Pb^2+ than total native cell membrane or cell membrane lipid.

Identification of hemolysin as one of the important virulent factors in vibrio anguillarum V7: Choe, Young Chool , Jeong, Ga Jin; J. Microbiol. 1995;33(4):283-288.

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Abstract: We have identified hemolysin rendering virulency of Vibrio anguilarum grown at 23℃ which was evaluated on human RBCs. Hemolysin itself was separated as a single band on non-denaturing gel electrophoresis. Vibrio hemolysin was destroyed by trypsin and proteinase K and was heat labile. Optimal pH for activity was around pH 6 while pI of the molecule was recognized as 5.7, with relative distance (R_f) on non-denaturing gel was 0.7. Addition of EDTA and FeCI₃drew the possibility that the production of hemolysin was mainly induced to overcome iron deficiency inside host animals upon infection.

Physiological characterization of kinetics and action mechanism of vibrio hemolysin: Choe, Young Chool , Jeong, Ga Jin; J. Microbiol. 1995;33(4):289-294.

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Abstract: The action mechanism of hemolysin rendering virulency of Vibrio anguilarum has not clarified as yet, even though there were several possible factors explained. We have studied hemolytic kinetics performed by hemolysin from V. anguillarum strain V7 as well as binding of hemolysin to RBC membrane. Maximal rate of hemolysis and duration of lag phase were directly and inversly correlated to the concentration of hemolysin used. Hemolysin molecules are known to bind consumptively with proper diameter, while other protectants with smaller diameter could not. In conclusion, hemolysin should bind irreversibly to RBC membrane exert hemolysis distorting osmotic pressure. The binding could be hindered by spatial structure of the RBC surfacem which might be caused by sialic acid.

The role and characterization of β-1,3-glucanase in biocontrol of fusarium solani by pseudomonas stutzeri YPL-1: Lim, Ho Seong , Kim, Sang Dal; J. Microbiol. 1995;33(4):295-301.

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Abstract: An antifungal Pseudomonas stutzeri YPL-1 produced extracellular chitinase and β-1,3-glucanase that were key enzymes in the decomposition of fungal hyphal walls. These lytic extracellular enzymes markedly inhibited mycelial growth of the phytopathogenic fungus Fusarium solani. A chitinase from P. stutzeri YPL-1 inhibited fungal mycelial growth by 87%, whereas a β-1,3-glucanase from the bacterium inhibited growth by 53%. Furthermore, co-operative action of the enzymes synergistically inhibited 95% of the fungal growth. The lytic enzymes caused abnormal swelling and retreating on the fungal hyphal walls in a dual cultures. Scanning electron microscopy clearly showed hyphal degradation of F. solani in the regions interacting with P. stutzeri YPL-1. In an in vivo pot test, P. stutzeri YPL-1 proved to have biocontrol ability as a powerful agent in controlling plant disease. Planting of kidney bean (Phaseolus vulgaris L.) seedlings with the bacterial suspension in F. solani-infested soil significantly suppressed the development of fusarial root-rot. The characteristics of a crude preparation of β-1,3-glucanase produced from P. stutzeri YPL-1 were investigated. The bacterium detected after 2 hr of incubation. The enzyme had optimum temperature and pH of 40℃ and pH 5.5, respectively. The enzyme was stable in the pH range of 4.5 to 7.0 and at temperatures below 40℃, with a half-life of 40 min at 60℃.

Effect of Zinc and Calcium on the Intracelularly uptake of Cadimium and growth of Escherichia coli: Hong, Hyo Bong , Brown, Lewis R. , Kim, Jong Kyu; J. Microbiol. 1995;33(4):302-306.

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Abstract: E. coli was tested for their ability to uptake cadmium intracellularly, and the effect of zinc and calcium on cadmium toxicity to E. coli was observed. In addition, the effect of zinc and calcium on the uptake of cadimium was also studied. This study showed that living E. coli cells took up more cadmium than the dead cells. E. coli in the log phase uptake cadimiumm more actively than E. coli in the stationary phase. These results suggested that there may be metabolic reactions or compounds which encourage the uptake of cadimium. This study also showed that cadimium was sequestered by cell components of which molecular weight is about 30,000. Adding of zinc and calcium chloride reduced cadmium toxicity in E. coli and encouraged intracellular uptake by E coli. However adding of heavy metal solutions helped the microorganisms to adsorb more cadmium. Extremely high or low concentrations of zinc, however, did not affect cell viability.

Characteristics of trypsin-like protease and metalloprotease associated with mycelium differentiation of streptomyces albidoflavus SMF301: Kang, Sung Gyun , Kim, In Seop , Jeong, Byung Cheol , Ryu, Jae Gon , Rho, Yong Taik , Lee, Kye Joon; J. Microbiol. 1995;33(4):307-314.

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Abstract: Trypsin like protease (TLP) and metalloprotease (MTP) were induced in associated with the mycelium differentiation in Streptomyces albidoflavus SMF301. TLP and MTP were purified and characterized from the culture. The molecular mass of TLP and MTP were estimated to be 32 kDa and 18 kDa, respectively. The molecular mass of TLP and MTP were estimated to be 32 kDa and 18 kDa, respectively. The optimum pH and temperature of TLP were 10 and 40℃. Those of MTP were 8 and 55 ℃. TLP was stable at alkaline pH (6-9) and unstable above 45℃ and MTP was stable at alkaline pH and unstable above 80℃. Km and Vmax values with benzoyl-arginyl p-nitroanilide of TLP were 139 uM, and 10 nmole of nitroanilide released per min per ㎍ protein, respectively. Km, and Vmax values with a synthetic substrate, leucine p-nitroanilide, or MTP were 58.9 uM, 3.47 nmol of nitroanilide released per min per/㎍ protein, respectively. TLP was inhibited competitively by leupeptin; the inhibition constant was 0.0031 uM. MTP was inhibited by EDTA, phenonthroline and bestatin.

Physiological importance of trypsin-like protease during morphological differentiation of streptomycetes: Kim, In Seop , Kang, Sung Gyun , Lee, Kye Joon; J. Microbiol. 1995;33(4):315-321.

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Abstract: The relationship between morphological differentiation and production of trypsin-like protease (TLP_ in streptomycetes was studied. All the Streptomyces spp. In this study produced TLP just before the onset of aerial mycelium formation. Addition of TLP inhibitor, TLCK, to the top surface of colonies inhibited aerial mycelium formation as well as TLP inhibitor, TLCK, to the top surface of colonies inhibited aerial mycelium formation as well as TLP activity. Addition of 2% glucose to the Bennett agar medium repressed both the aerial mycelium formation and TLP production in S. abuvaviensis, S. coelicolor A3(2), S exfoliatus, S. microflavus, S. roseus, s. lavendulae, and S. rochei. However the addition of glucose did not affect S. limosus, S. felleus, S. griseus, S. phaechromogenes, and S. rimosus. The glucose repression on aerial mycelium formation and production of TLP was relieved by the addition of glucose anti-metabolite (methyl α-glucopyranoside). Therefore, it was concluded that TLP production is coordinately regulated with morphological differentiation and TLP activity is essential for morphological differentiation in streptomycetes. The proposed role of TLP is that TLP participates in the degradation of substrate mycelium protein for providing nutrient for aerial mycelial growth.

Induction of ethanol tolerance on the production of 17-ketosteroids by mutant of mycobacterium sp.: Kim, Mal Nam , Kim, Eun Mi; J. Microbiol. 1995;33(4):322-327.

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Abstract: Tolerance of Mycobacterium sp. against organic solvents has been induced for the cholesterol side chain degradation by adding chemicals associated with synthesis of fatty acids or alcohols. Biotin of 300 ㎍/1 and 0.5% aqueous ethanol solution were optima for the enhancement of ethanol tolerance of the microorganism. The induction of ethanol tolerance by biotin was found to be due to increase of degree of unsaturation of the fatty acids in membranous phospholipid of the cell, especially due to increase of oleic acid content. However when 0.5% of ethanol was added for the ethanol tolerance induction, there was an ambiguous correlation between ethanol tolerance and degree of unsaturation of the fatty acids, in spite of the fact that the induction increased the content of unsaturated fatty acids. Addition of 0.5% of ethanol induced several ethanol shock proteins having molecular weight similar to that of heat shock proteins.

Characterization of C-P Lyase gene cluster by in vivo ³¹P-NMR spectroscopy: Lee, Ki Sung , Kwak, In Young; J. Microbiol. 1995;33(4):328-333.

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Abstract: ³¹P-NMR experiment was performed to detect phophonates (Pn) utilization and degradation in the several different C-P lyase mutants of E. coli and in E. aerogenes and the recombinants. The relative peak intensity (RPI) for the standard samples of 0.5 mM methylphosphonate (MPn) and 1.0 mM aminoethylphosphonate in glucose-MOPS medium showed 0.5 : 1.0 ratio. In the case of BW14329 (ΔphnC-P, ΔphoA), RPI did not change significantly after 24 hrs culturing, which means it nearly could not utilize Pn. In vivo ³¹P-NMR spectrum of E. aerogens (BWKL 16627) during 3 hrs starvation showed two intense peaks at 0-2 ppm and at near-10 ppm which indicate intracellular orthophosphate (Pi) and pyrophosphate (PPi), respectively. Both of them might be released by degradation of inorganic polyphosphate pool. When MPn is supplied to the medium as an unique P source, Pi content in the cell has the constant, but PPi seems to be slightly decreased. Recombinants (BWKL 16954) grew slower than E. aerogenes in the glucose-MOPS media with various P sources. In vivo ³¹P-NMR spectrum of recombinant did not show any intense signal in the cell. Surprisingly, under the cultivation adding with MPn, a few intense peaks in the region of Pi AND phospate monoester were detected.

Comparison of electrophoretic karyotypes in fusarium: Min , Byung Re; J. Microbiol. 1995;33(4):334-338.

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Abstract: The electrophoretic karyotypes of 6 species in different Fusarium sections were examined by using contour-clamped homogeneous electric field (CHEF) gel electrophoresis. Intact chromosomal DNA was prepared from protoplasts and up to 9 distinct bands were separated on 0.7% or 0.8% agarose gel under several different conditions. Putative chromosome numbers varied from 6 to 9 amd polymorphic karyotypes were observed in different Fusarium sections. Using Schizosaccharomyces pombe and Saccharomyces cerevisiae chromosomes as standards, the sizes of the Fusarium spp. chromosomes were estimated. The electrophoretic karyotypes of F. moniliforme and F. subglutinans (section Liseola) were similar. Unidentified filamentour fungi, F. beomiforme was much closer to F. axysporum (section Elecgans) in karyotype and the karyotypes of F. napiforme were more similar to those of section Liseola than any other sections. F. graminearum (section Discolor) had a distinctive electrophoretic karyotype.

Pleiotrohpic effect of a gene fragment conferring H₂O₂resistance in streptomyces coelicolor: Um, Tae Han , Oh, Chung Hun , Lee, Jong Soo , Park, Yong Doo , Roe, Jung Hye , Kim, Jae Heon; J. Microbiol. 1995;33(4):339-343.

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Abstract: We isolated a 10 kb Bam HI fragment originated from the chromosome of a H₂O₂-resistant mutant strain of Streptomyces coelicolor, which confer H₂O₂-resistance to S. lividance upon transformation. Among various subclones ot 10kb Bam HI fragment tested for their H₂O₂-resistant phenotype in S. lividans, a subclone containing 5.2 kb Bam HI-BglII fragment was found to be responsible for H₂O₂-resistance. The plasmid containing this 5.2 kb fragment was then transformed into S. coellicolor A3(2) at early and tested for their phenotype of H₂O₂-resistance and the change in various enzymes whose activity can be stained in the gel. We found out that the 5.2 kb insert DNA conferred H₂O₂-resisstance in S. coelicolor A3(2) at early phase of cell growth. The presence of this DNA also resulted in higher level of peroxidase compared with the wild type cell containing parental vector (pIJ702) only. Esterase activity was also higher in this clone. However, alcohol dehydrogenase activity decreased compared with the wild type. These results suggest that the presence of a gene in 5.2 kb BamHI-BglII DNA fragment causes multiple changes in S. coelicolor related to its response against hydrogen peroxide. The result also implies that not only peroxidase but also esterase may function in the defencse meahsnism agianst H₂O₂.

Cloning of the gense coding for extracellular proteases from alkalophilic xanthomonas SP. JK311: Kim, Young Hun , Jang, Ji Yeon , Yeeh, Yeehn , Kim, Yong Ho , Kim, Sang Hae; J. Microbiol. 1995;33(4):344-349.

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Abstract: The alkalophilic bacterium, Xanthomonas sp. JK311, producing extracellular proteases, was isolated from soil. Xanthomonas sp. JK311 produced five extracellular proteases that are all metalloproteases. Four of them were resistant against 1% SDS. Chromosomal DNA of the Xanthomonas sp. JK311 was digested with BamHI and cloned into PUC19. Among E. coli strain HB101 transformants, a clone secreting the proteases was screened through halo formation on skim-milk agar plate and by Southern blot analysis. It had the recombinant plasmid pXEP-1 containing the 7.5 kb-BamHI DNA fragment and produced three extacellular proteases. Their protease properties corresponded to those of Xanthomonas sp. JK311.

Sequence analysis of the schizosaccharomycs pombe homologue of the CDC3 gene in saccharomyces cerevisiae: Kim , Hyong Bai; J. Microbiol. 1995;33(4):350-354.

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Abstract: Saccharomyces cervisiae has a highly ordered ring of filaments that lies just inside the cytoplasmic membrane in the region of the mother-bud neck. Mutants defective in any one of the our cell division cycle genes (CDC3, CDC10, CDC11, CDC12) fail to form these filaments and exhibit a pleiotropic phenotype that includes failure to complete cytokinesis and abnormal bud growth. However, the role of the filament is not clear. In order to find out the role of filament, the similar gene in S pombe (called cdc103^+) to the CDC3 was cloned and sequenced. Here I report the sequence analysis of the cdc103^+) to the CDC3 was cloned and sequenced. Here I report the sequence analysis of the cdc103^+. Comparison of the predicted amino acid sequences of cdc103^+ and CDC3 revealed that they share significant similarity (43% identity and 56% identity or similarity) to each other.

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