• Korean Journal of Microbiology
• /
• v.24 no.3
• /
• pp.251-262
• /
• 1986

High-molecular-weight ${\beta}-glucosidase$ (EC 3.2.1.21) was purified from the culture filtrate of Trichoderma koningii through a four-step procedure including chromatography on Bio-Gel P-150, DEAE-Sephadex A-50 and SP-Sephadex C-50; and chromatofocusing on Polybuffer exchanger PBE 94. The molecular weight of the enzyme was determined to be about 101,000 by SDS-polyacrylamide gel electrophoreses, and the isoelectric point was estimated to be 4.96 by analytical isoelectric focusing. The temperature optimum for activity was about $55^{\circ}C$, and the pH optimumwas 3.5. The enzyme was considerably thermostable, for no loss of activity was observed when the enzyme was preincubated at $60^{\circ}C$ for 5h. Km values for cellobiose, gentiobiose, sophorose, salicin and $p-nitrophenyl-{\betha}-D-glucoside$ were 99.2, 14.7, 7.09, 3.15 and 0.70 mM, respectively, which indicates that the enzyme has much higher affinity towards $p-nitrophenyl-{\betha}-D-glucoside$ than towards the other substrates, especially cellobiose. Substrate inhibition by $p-nitrophenyl-{\betha}-D-glucoside$ and salicin was observed at the conecntrations exceeding 5mM. Gluconolactone was a powerful inhibitor against the action of the enzyme on $p-nitrophenyl-{\betha}-D-glucoside\;(K_i\;37.9\;{\mu}M)$, wherease glucose was much less effective ($K_i$ 1.95 mM). Inhibition was of the competitive type in each case. Transglucosylation activity was detected shen the readtion products formed from $p-nitrophenyl-{\betha}-D-glucoside$ by the enzyme were analysed using high-performance liquid chromatography.

• Korean journal of applied entomology
• /
• v.10 no.2
• /
• pp.97-101
• /
• 1971

1. The experiment was conducted to investigate the physiological characteristics on ten isolates of bacterial leaf blight pathogen of rice, Xanthomenas eryzae Dowson. Seven out of tin isolates were isolated from infected leaves of various rice varieties including IR strains in Korea. Isolates S-20 and S-103 were originated from IRRI in Philippines, and isolate H-5809 was allocated by National Institute of Agricultural Science in Japan. 2. All isolates Produced hydrogen sulfide and ammonia 9as from peptone sol. media, and reduced methylen blue, Gelatin liquefaction occurred by all isolates tested, although each isolate showed different degree of liquefaction No coagulation of the casein in milk by the isolates was observed, though some amount of acid production occurred in litmus milk by ail isolates tested. 3. All isolates utilized glucose and galactose, and slight utilization of esculin, mannitol, raffinose, salicin and saccharose was observed. Lactose, starch and dextrin, however, were not utilized at all by all isolates tested in the study.

• Journal of the Korean Wood Science and Technology
• /
• v.28 no.3
• /
• pp.52-61
• /
• 2000

Black locust(Robinia pseudoacacia) and poplar(Populus alba ${\times}$ glandulosa) trees were collected, extracted with acetone-$H_2O$(7:3, v/v) after drying, fractionated with hexane, chloroform and ethylacetate, and freeze dried to get some brown powder. Each fraction of the powder was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluting solvents. The wood extractives of black locust contained (+)-leucorobinetinidin as flavan, robtin as flavanone and dihydrorobinetin as flavanonol, and robinetin as flavonol. The poplar bark extractives contained various kinds of phenolic compounds : (+)-catechin as flavan, naringeoin, eriodictyol, sakuranetin, aromadendrin and taxifolin as flavanonol, salireposide as salicin derivative, and minor compounds such as aesculin and p-coumaric acid. However, aesculin has not been reported as a constituent of the poplar bark in Korea yet. NMR and FAB-MS analyses were done to elucidate the structures of isolated phenolic constituents.

• Journal of environmental and Sanitary engineering
• /
• v.6 no.1
• /
• pp.31-46
• /
• 1991

Aeromonas hydrophila which bacause various diseases in human also infects fresh water fish, severly damaging the fishing industries. To prevent disease in humans and reduce damaging on the fishing industries, We have examined several characteristics of Aeromonas hydrophila and obtained the following results. All of the strains gave a posive voges-proskauer, methyl-red, salicin and esculin reaction. Seventeen(94.4%) A. hydrophila strains presented the phenotype SP-PAB- in autoagglut-ination test, but only strain AH 997 showed $SP^{+}PAB^{+}$. in autoagglut ination test, but only strain AH 997 $SP^{+}PAB^{+}$ All of the strains took up the censored to various degrees. Three of 18 strains showed positive reaction in crystal violet binding test. Hemolytic activity ranged from titers of 0 to 1/256. Seven of the 17(38.8%) A. hydrophila strains were positive in sucking mouse assay. Cytotoxin activity on vero and RK cells was displayed various titers.(1/2-1/1024)

• Korean Journal of Microbiology
• /
• v.30 no.5
• /
• pp.339-346
• /
• 1992

These studies were carried out to identify Bacillus cereus group 1..5-] strain isolated from 5uyeong Bay. This strain was differentiated from B. cereus group using conventional, API system and fatty acid composition analysis. Colony characteristics were opague. mucoid, entire margin. convex. circular and non hemolysis on sheep blood agar plates, and were observed with central spore forming positive bacilli in a Gram stained preparation. and had no motility. The carbohydrates tested; glucose.maltose, and sucrose were assimilated but neither trehalose nor salicin were assimilated. This strain ultilized gelatin and was also inhibited by 6.5% NaCI. The results of biochemical examination were differented from B. cereus group LS-1 compared with others B. cereus group. The fatty acid composition contained major amounts of branched chain acids. iso $C_{15}$ and iso $C_{13}$ and the range of chain length was $C_{12}$ to C"$C_{17}$ and n$C_{15}$, acid was not detected. Automated fatty acid computer profile indicated "B. mycoides GC subgroup B of 0.312 similarity index." The results agreed with other research cases. On the other hand. A TB computer prolile index of API system (API 50 CHB & API 20E) identified" Doubtful profile of 99.7% B. firmus" . These results were presented with considerable discrepancies between API system and fatty acid analysis. With 67 biochemical characters. the similarity matrix of B. mycaides (KCTC 1033). B. thuringiensis (KCTC 1033). B. cereus (5-3) and B. mycoides (S-12) showed 42%. 42%. 59%, and 52%. respectively. Through the key tests and fatty acid analyses. we could notice the appearance of B. mycoides of the B. cereus group and this leads us to suspect the existence of a new biotype B. mycoides.

• KSBB Journal
• /
• v.10 no.4
• /
• pp.374-385
• /
• 1995

Nutritional requirements and cultural conditions for the production of extracellular gelatin-degrading proteolytic enzyme by Bacillus subtilis B0021 were investigated. Optimum carbon source for proteolytic enzyme production was salicin, but it was substituted by glucose for economical reason. The fermentation medium giving a maximum proteolytic enzyme activity was consisted of 1.5%(w/v) glucose, 2.5%(w/v) yeast extract, and 0.001%(w/v) manganese sulfate and 0.002%(w/v) ferrous sulfate. Proteolytic enzyme activity of B. subtilis B0021 was completely inhibited by 0.5%(w/v) tannic acid. Initial pH was optimal at 7.0 and the enzyme activity in the flask culture usually reached a maximal level after 36 hours of fermentation at $30^{\circ}C$. In the $5\ell$ fermentor fermentation at $30^{\circ}C$, enzyme activity was maximum at 36 hour of cultivation but after this enzyme activity was decreased rapidly. Initial viscosity of 45%(w/v) gelatin(2,800mPas) was decreased rapidly to 96%(mPas) after hydrolysis for 4hr at $40^{\circ}C$ by crude enzyme of B. subtilis B0021.

• Journal of Life Science
• /
• v.16 no.7 s.80
• /
• pp.1148-1157
• /
• 2006

A hyperthermophilic bacterium Thernotoga maritima produced thermostable ${\beta}-glucosidase$. The gene encoding ${\beta}-glucosidase$ from T. maritima MSB8 was cloned and expressed in Escherichia coli. The en-zyme (BgIB) hydrolyzed ${\beta}-glucosidase$ linkages between glucose and alkyl, aryl of saccharide groups such as salicin, arbutin, and $_pNPG$. The insert DNA contained ORF with 2,166 bp encodes a 721 amino acids (calculated molecular mass of 80,964 and pl of 4.93). The amino a.id sequence of BglB showed the similarity to family 3 glycosyl hydrolases. The molecular weight of the enzyme was estimated to be approximately 81kDa by MUG-nondenaturing PAGE (4-methylumbelliferyl 13-D-glucoside-nondenaturing polyacrylamide gel electophoresis) and SDS-PACE. The ${\beta}-glucosidase$ exhibited maximal activity at pH 7.0 and $80^{\circ}C$. By exchanging two possible residues (Glu-232 and Asp-242) to Ala by site-directed mutagenesis method, it was found that these were essential for enzymatic activity.

• Journal of Microbiology and Biotechnology
• /
• v.6 no.4
• /
• pp.255-259
• /
• 1996

$\beta$-Glucosidase was known to be involved in the mutagenic activation of $\beta$-glucosides. The level of $\beta$-glucosidase in the feces of adults was 2.7 times higher than that of infants. There was no difference in the percentage of $\beta$-glucosidase positive strains among Bifidobacterium isolates between adults and infants, corresponding to 90 and 92$%$, respectively. However, the strains from adults showed 1.9 times higher enzyme activity than those from infants when grown in Brain Heart Infusion medium. $\beta$-Glucosidase negative strains could not ferment $\beta$-glucosidase substrates, such as cellobiose, salicin, naringin, esculin and arbutin. Presence of $\beta$-glucosidase in Bifidobacterium did not alter the degree of growth in reconstituted skim milk. The $\beta$-glucosidase level was much lower in milk and vegetable medium, although cells grew above $10^8$cfu/ml, than in BHI medium. This study suggests that metabolic activation of the $\beta$-glucosides by Bifidobacterium $\beta$-glucosidase varies significantly depending on types of growth medium.

• Microbiology and Biotechnology Letters
• /
• v.19 no.1
• /
• pp.8-13
• /
• 1991

Bacteriocin-producing microorganisms were screened from raw milk and tested their antimicrobial activities against Lactobacillus plantarum ATCC 8014 as target organism, Antimicrobial substances isolated showed broad antimicrobial spectra against Gram positives and negatives. Strain 1112-1 was selected as a test organism due to its highest antimicrobial activity among the isolates. Antimicrobial substance produced by 1112-1 completely suppressed the growth of Lactobacillus plantarum at 230 IUIml and showed 11% growth inhibition of E. coli at 500 IUIrnl level. The antimicrobial substance was found to be proteinaceous material which was inactivated by carboxypeptidase, elastase, alpha amylase, amyloglucosidase, pronase, protease IV, alpha chymotrypsin, ficin, cellulase, phosphatase and lipase. The molecular weight was estimated by SDS-PAGE as 5,900. The isolate 1112-1 was identified as one of the related strains of Lactococcus sp. The strain was different from Lactococcus lactis in the following characteristics: late positive in maltose and sucrose fermentation; positive in mannitol and salicin fermentation; negative in lactose fermentation.

• The Journal of the Korean Society for Microbiology
• /
• v.22 no.4
• /
• pp.427-433
• /
• 1987

One hundred and thirty-six strains of Klebsiella pneumoniae were isolated from clinical specimen taken from pediatric patiants at 6 different hospitals and identified, characterized and investigated on the patterns of antibiotic resistance. The 136 strains showed the positive reactions in the 17 tests; Voges-Proskauer, ONPG, cirate utilization, KCN degradation, productions of lysine decarboxylase, acid and gas from glucose, utilizations of malonate, manitol, rhamnose, salicin, sucrose, raffinose, arabinose, lactose, sucrose, inositol and raffinose, but the strains showed the negative reactions in the 8 tests; production of $H_2S$, indole, arginine dehydrolase, ornithine decaraoxylase, phenylalanine deaminase, motility, methly red and gelatin liquefaction. 41 did not utilize dulcitol, and 32 did not utilize adonitol. The 36 out of them produced klebecin. The 136 strains were resistant to ampicillin, 2 to gentamicin, 14 to cephalothin, 16 to chloramphenicol, 8 to kanamycin, 13 to streptomycin, and 17 to tetracycline. Twenty strains were resistant to 2 kinds of antibiotics 5 strains to 3, 4 to 4 and 1 to 6 and 7.