• Journal of Sericultural and Entomological Science
• /
• v.24 no.2
• /
• pp.73-80
• /
• 1983

1. The varietal difference in amylase activity of the digestive fluid of the 5th instar larvae reared on the artificial diet was investigated, using the parent commercial silkworm varieties of Japanese strain. The amylase activity was large different among silkworm varieties. The activity was strong in Hansaeng-1, Jam 115 and Jam 117, medium in Hansaeng-3, Jam 113, Jam 119, and Jam 201, weak in Jam 107, Jam 121 and Gyeongchu. The amylase of the digestive fluid of ten parent commercial silkworm varieties is possible-(ae) type, compared with ＋(＋$\^$ae/) type of Daizo. 2. To investigate the effect of a-amylase pre-treatment of the artificial diet, larvae were fed with the diet treated by a-amylase during 4th-5th instar periods. The blood sugar content and cocoon qualities were slightly higher in the experimental larvae than those in the control, while showing the slight less body weight, amylase activity and dietary efficient.

• Korean Journal of Microbiology
• /
• v.11 no.2
• /
• pp.89-100
• /
• 1973

Dextrinogenic and saccharogenic amylase activities of Rhizopus isolated from various substrates collected throughout South Korea are measured, and their amylase activities are surveyed from taxnomical, ecological, and physiological viewpoints. Among the 151 strains of Rhizopus, strain number 49 exhibiting most prominent saccharogenic amylase activity is selected as a best strain, and strain number 17 is selected as a best strain for dextrinogenic amylase activity. Amylase activities of Rhizopus are so variable in different strains even in the same species. In general, however, R. japonicus, R. liquefaciens, and R. shanghaiensis show high saccharogenic amylase activities, and R.chiuniang, R.achlamydosporus, and R.bahrnensis show high dextrinogenic amylase activities, while R.nigricans exhibits lower activities for both amylase. The strains isolated from kneaded cereals, such as "meju" and "kockja", exhibited very strong dextrinogenic and saccharogenic amylase activities as compared with the strains isolated from other sunstrates. The mean value of dextrinogenic amylase activities of the strains from southern inland region and saccharogenic amylase activities of the strains from middle coast region are, more or less, higher than those of the strains from the other regions. In the culture at 30.deg.C, those strains which exhibit better mycelial and air mycelial growth than sporangial formation show very high dextrinogenic and saccharogenic amylase activities. amylase activities.

• Microbiology and Biotechnology Letters
• /
• v.27 no.3
• /
• pp.203-207
• /
• 1999

V. alginolyticus 138-2, a marine halophilic bacterium, produced an extracellular amylase with a molecular weight of ca. 56,000. The analysis of the digestion products of soluble starch by thin layer chromatography(TLC) revealed that the extracellular amylase of V. alginolyticus 138-2 is a saccharifying-type alpha-amylase. The alpha-amylase activity of the culture supernatant of soluble starch was optimal at pH 6.0 and 45$^{\circ}C$. Ca2+ slightly increased the alpha-amylase activity, whereas Hg2+, An2+, Cu2+, Ni2+, Fe2+, and Mn2+inhibited the enzymatic activity. Alkylating thiol group agent, iodoacetic acid did not affect the alpha-amylase activity, but reduced thiol reagents such as dithiothreitol, cysteine, and beta-mercaptoethanol stimulated theenzymatic activity. On the other hand, even if V. alginolyticus 138-2 is a marine halophilic bacterium, its alpha-amylase activity was significantly inhibited by NaCl.

• Journal of Microbiology and Biotechnology
• /
• v.2 no.2
• /
• pp.115-121
• /
• 1992

In order to broaden the spectrum of substrate utilization of a Gram negative bacterium Zymomonas mobilis which has a great potential as an industrial ethanol producing microorganism, cloning of $\alpha$-amylase gene into Z. mobilis ZM4 was tried. The $\alpha$-amylase gene was isolated from Bacillus stearothermophilus. By Southern blot analysis, it was proven that the $\alpha$-amylase gene fragment was originated from a naturally occuring plasmid of B. stearothermophilus ATCC 31195. To place $\alpha$-amylase gene under the control of Z. mobilis promoter, two different Z. mobilis expression vectors, pZA26 and pLOI204, were used. The truncated $\alpha$-amylase gene was then introduced into these vectors. Both qualitative and quantitative activities of $\alpha$-amylase were observed in Z. mobilis cells harboring these plasmids with the $\alpha$-amylase gene inserted. Gas chromatographic analysis of ethanol showed that one of the Z. mobilis transconjugants was capable of producing 67 mM ethanol from rich medium(RM) containing 5% soluble starch as a sole carbon source.

• Microbiology and Biotechnology Letters
• /
• v.14 no.2
• /
• pp.161-168
• /
• 1986

A 1.95Kb Sau3Al fragment coding for $\alpha$-amylase from Bacillus amyloliquefaciens was isolated by the shotgun method using Escherichia coli as a host. The genome of Bacillus amyloliquefaciens was partially digested with the restriction endonuclease Sau3Al and joined to plasmid YRp7 cleaved with the restriction endonuclease BamHI. The $\alpha$-amylase gene present in a 1.95Kb insert was stably maintained and expressed in Escherichia coli. The amount of $\alpha$-amylase activity produced by Escherichia coli containing the hybrid plasmid pEA24 was about 65% of the activity produced by the donor Bacillus amyloliquefaciens strain. The properties of $\alpha$-amylase produced by Escherichia coli were very similar to those produced by Bacillus amyloliquefaciens as based on optimum temperature, pH, and effect of CaCl$_2$ concentration. About 70% of the $\alpha$-amylase produced by Escherichia coli was localized in the periplasmic space, whereas the remaining enzyme was localized in the inner part of the cell.

• Journal of Plant Biology
• /
• v.20 no.2
• /
• pp.91-101
• /
• 1977

Using barley seeds (Hordeum sativum Jess, var.), the influences of gibberellic acid (GA) and indole-3-acetic acid(IAA) on the amylase synthesis and that of the nucleic acid metabolism were investigated. 1. With the deembrynized barley seeds, the increase of amylase treated with a $10^{-5}M$ of GA and the decrease of amylase treated with $10^{-5}M$IAA were matched by a proportionate increase and decrease in the amount of RNA. The influence of the hormones on the RNA synthesis has appeared immediately after the treatment but on the amylase synthesis it has appeared 8 hours later. But no influence on the DNA synthesis was observed on both hormones. 2. The amylase from deembryonized barley seeds treated with GA and IAA have been fractionated by gel filteration on Sephadex G-100. The amylase components showed four fractions on both enzymes treated with GA and IAA. Fraction I(FI) was differed from fraction Ⅵ(FIV) in Km value and the effects of temperature, pH and metal ions. On the basis of their emzymatic properties, it was considered that the FI was $\beta$-amylase and FIV was $\alpha$-amylase. The influences of GA and IAA on each fractions appeared to be similar but on the amylase units per souble protein, IAA inhibited the production of amylase FIV while it promoted that of amylase FI. 3. An experiment was conducted to determine whether IAA inhibits GA-promoted amylase synthesis competitively or non-competitively. Using a Lineweaver-Burk plot, it was clear that IAA was acting in a non-competitive fashion. From this, IAA was probably not competing with GA at the same site, but it was acting at some other site which resutled in partial blocking of the action of GA on the amylase synthesis.

• YAKHAK HOEJI
• /
• v.33 no.3
• /
• pp.175-182
• /
• 1989

To find ${\alpha}-amylase$ inhibitors produced by microorganisms from soil, a strain which had a strong inhibitory activity against bacterial ${\alpha}-amylase$ was isolated from the soil sample collected in Korea. The morphological and physiological characteristics of this strain on several media and its utilization of carbon sources showed that it was one of Streptomyces species according to the International Streptomyces Project method. The amylase inhibitor of this strain was purified by active carbon adsorption, silicagel column chromatography, SP-Sephadex C-25 column chromatography, adsorption on Amberlite XAD-2. The inhibitor was oligosaccharide which was composed of glucose. The inhibitor had inhibitory activity against other amylase such as salivary ${\alpha}-amylase$, pancreatic ${\alpha}-amylase$, fungal ${\alpha}-amylase$ and gluco-amylase.

• Microbiology and Biotechnology Letters
• /
• v.40 no.4
• /
• pp.296-302
• /
• 2012

A bacterial strain was isolated from soybean paste fermented in a Korean Buddhist temple as a producer of the extracellular thermostable ${\alpha}$-amylase. The isolate YB-1234 has been identified as Bacillus licheniformis on the basis of its 16S rDNA sequence, morphology and biochemical properties. A gene encoding the thermostable ${\alpha}$-amylase of B. licheniformis YB-1234 was cloned into Escherichia coli and its nucleotide sequence was determined. The deduced amino acid sequence of ${\alpha}$-amylase was very highly homologous to those of the thermostable ${\alpha}$-amylases of B. licheniformis belonging to the glycosyl hydrolase family 13. The ${\alpha}$-amylase produced by recombinant E. coli carrying the ${\alpha}$-amylase gene exhibited maximal activity at pH 6.0, identical to ${\alpha}$-amylase in the culture filtrate of B. licheniformis, while the temperature profile was somewhat different between the two. Particularly, ${\alpha}$-amylase produced from B. lcheniformis is much more thermostable than that from recombinant E. coli. The predominant products resulting from the ${\alpha}$-amylase hydrolysis were glucose, maltose and maltotriose for maltotetraose and maltohexaose.

• Microbiology and Biotechnology Letters
• /
• v.13 no.4
• /
• pp.349-354
• /
• 1985

A 4.7 kb Hind III fragment containing $\alpha$-amylase gene of Bacillus stearothermophilus IAM 11062 was cloned in Escherichia coil HB101, using plasmid pBR322 and runaway plasmid pSY343 as a vector. The cloned gene was stably maintained and expressed In E.coli. The constructed strain of E. coli have at least 3 times higher amylase activity than the donor strain, of B. stearothermophilus. About 75％ of the $\alpha$-amylase produced by the constructed strain of E. coli was localized in the periplasm and it was found that the enzymes can be released by an osmotic shock using EDTA. The enzymatic properties of L-amylase produced in E. coli were very similar to those produced by B. stearothermophilus in terms of optimum temperature, heat stability and molecular weight.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.16 no.2
• /
• pp.128-135
• /
• 1987

Extracellular ${\alpha}-amylase$, ${\beta}-amylase$ and glucoamylase produced by a thermophilic and cellulolytic bacterium, Herpetosiphon geysericola CUM 317, were partially purified by salting out with ammonium sulfate and by chromatography on a DEAE-cellulose column and on a CM-cellulose column. The Km values of ${\alpha}-amylase$, ${\beta}-amylase$ and glucoamylase for potato starch were $2.31mg/m{\ell}$, $7.69mg/m{\ell}$, and $8.33mg/m{\ell}$. The molecular weights of ${\alpha}-amylase$, ${\beta}-amylase$ and glucoamylase were calculated to be about 84000 dalton, 76000 dalton and 80000 dalton, respectively.