• Food Science and Preservation
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• v.17 no.2
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• pp.290-296
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• 2010

To develop anti-acidosis and anti-diabetes agentsfrom natural products, the inhibitory activities of Brazilian plant extracts against microbial $\alpha$-amylase and $\alpha$-glucosidase were evaluated. Among 100 different ethanol extracts tested, those of Acacia jurema Mart., Anacardium humile A. St.-Hil., Cedrela odorata L., and Guazuma ulmifolia Lam showed good inhibitoryactivities toward both enzymes. In addition, an extract of Plumeria drastica Mart. showed specific inhibition of $\alpha$-amylase, whereas that of Eugenia uniflora L. demonstrated strong inhibition of the enzyme. IC50 values of $\alpha$-amylase inhibition suggested that the extract of A. humile A. St.-Hil., which has been used as an anti-diabetes medicine in Brazil, had potent inhibitory activity. The IC50 for the A. humile A. St.-Hil. extract ($91.2{\mu}g/mL$) was similar to that of acarbose ($50.5{\mu}g/mL$). This activity of A. humile A. St.-Hil. was not reduced by heat or acid treatment. Moreover, treatment with HCl (0.01 M) for 1 h increased the inhibitory activity from 57.5% to 81.2%. Also, the extract did not cause hemolysis of human red blood cells at levels up to 1 mg/mL. The results indicate that the extract of A. humile A. St.-Hil. is potentially useful as an anti-acidosis and anti-diabetes agent.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.349-354
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• 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 Microbiology and Biotechnology
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• v.24 no.2
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• pp.254-263
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• 2014

Enteromorpha polysaccharides (EP) extracted from green algae have displayed a wide variety of biological activities. However, their high molecular weight leads to a high viscosity and low solubility, and therefore, greatly restrains their application. To solve this problem, bacteria from the surface of Enteromorpha were screened, and an Alteromonas macleodii strain B7 was found to be able to decrease the molecular weight of EP in culture media. Proteins harvested from the supernatant of the A. macleodii B7 culture were subjected to native gel electrophoresis, and a band corresponding to the Enteromorpha polysaccharide lyase (EPL) was detected by activity staining. The enzyme identity was subsequently confirmed by MALDI-TOF/TOF mass spectrometry as the putative ${\alpha}$-amylase reported in A. macleodii ATCC 27126. The amylase gene (amySTU) from A. macleodii B7 was cloned into Escherichia coli, resulting in high-level expression of the recombinant enzyme with EP-degrading activity. AmySTU was found to be cold-adapted; however, its optimal enzyme activity was detected at $40^{\circ}C$. The ${\alpha}$-amylase was highly stable over a broad pH range (5.5-10) with the optimal pH at 7.5-8.0. The highest enzyme activity was detected when NaCl concentration was 2%, which dropped by 50% when the NaCl concentration was increased to 16%, showing an excellent nature of halotolerance. Furthermore, the amylase activity was not significantly affected by tested surfactants or the presence of some organic solvents. Therefore, the A. macleodii strain B7 and its ${\alpha}$-amylase can be useful in lowering EP molecular weight and in starch processing.

• Restorative Dentistry and Endodontics
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• v.38 no.3
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• pp.141-145
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• 2013

Objectives: Assessment of dental pain severity is very challenging in dentistry. Previous studies have suggested that elevated salivary alpha amylase may contribute to increased physical stresses. There is a close association between salivary alpha amylase and plasma norepinephrine under stressful physical conditions. The aim of this study was to evaluate the relationship between pain severity and salivary alpha amylase levels in patients with symptomatic irreversible pulpitis. Materials and Methods: Thirty-six patients (20 females and 16 males) with severe tooth pain due to symptomatic irreversible pulpitis were selected. The visual analogue scale (VAS) score was used to assess the pain severity in each patient. Unstimulated whole saliva was collected, and the level of alpha amylase activity was assessed by the spectrophotometric method. Statistical analysis was performed using SPSS 13. Results: The level of alpha amylase was significantly increased in the saliva in association with pain severity assessed by VAS. The salivary alpha amylase was also elevated with increased age and in males. Conclusions: There was a significant correlation between the VAS pain scale and salivary alpha amylase level, which indicates this biomarker may be a good index for the objective assessment of pain intensity.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.625-630
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• 1998

Using a modified yeast secretory expression vector, $\alpha$-amylase of Schwanniomyces occidentalis was produced from Saccharomyces cerevisiae. The expression vector contains the a-amylase gene (AMY) harboring its own promoter without the regulatory region and the adenine base at the -3 position from the ATG start codon, its own signal sequence, CYC1 transcription terminator, and SV40 enhancer. The expressed $\alpha$-amylase activity from cells carrying the plasmid was approximately 26 times higher than that from the cells harboring an unmodified plasmid. When Saccharomyces diastaticus was transformed with this modified vector, a 2.5 times higher level of amylolytic activity than that from Sch. occidentalis was observed.

• Food Science and Preservation
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• v.8 no.4
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• pp.405-411
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• 2001

This study was conducted to investigate the effect of rice powder m tile enzyme (protease, $\alpha$-amylase, $\beta$-amylase and glucoamylase) activities of soybean meju fermented by Monascus prepureus and Monascus pilosus. The activities of the enzyme in the rice meju and the soybean meju fermented by M. pilosus were higher than those by M. perpureus. Protease activity of powdered rice meju was higher than that of granular rice meju, while $\alpha$-amylase, $\beta$-amylase and glucoamylase activities were higher in granular rice meju. Protease activity in soybean meju fermented by adding of the cultured medium of Monascus strains(CMM) as a seed inocula were higher than those of the rice powder meju, while $\alpha$-amyulase, $\beta$-amylase and glucoamylase activiities were lower than those of soybean meju by CMM. The concentration of rice powder to show maximum protease activity in soybean meju was also 10% against steamed soybean. But $\alpha$-amylase activity of soybean medju by the CMM added 2% powdered rice showed lower but the activity increaed with an increase in powdered rice, whereas $\beta$-amylase and glucoamylase activiities decreased with an increase in powdered rice. Protease activity of soybean meju fermented by 10% rice meju fermented by M. pilo년 as a seed inocula was higher than that of the meju fermented by Aspergillus oryzae, whereas $\beta$-amylase and glucoamylase activities of the soybean meju showed less than 50%.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.412-420
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• 1989

To know how the ribosomes involved in secretory protein synthesis were attached to the cytoplasmic membrane in Bacillus amyloliquefaciens, the cells were treated with puromycin combinated with magnesium at the logarithmic phase, and the variation of cell-bound and extracellular $\alpha$-amylase activity was assayed for determining the $\alpha$-amylase translocation blocking through the cytoplasmic membrane. In the abnormal $\alpha$-amylase producing mutant in which the C-terminal of the $\alpha$-amylase structure was deleted, B. umytotiquefaciens CH10-2, the $\alpha$-amylase was translocated normally through the cytoplasmic membranes, and the translocation blocking by puromycin was revealed to have a similar pattern as that in the wild type. This means that the C-terminal part of the enzyme structure may not have a signal for secretion. The cell death of the logarithmic phase cells in both strains was not affected much under 20$\mu\textrm{g}$/$m\ell$ of puromycin, however, the $\alpha$-amylase translocation was blocked markedly under less than 10$\mu\textrm{g}$/$m\ell$ of the puromycin concentration. The blocking of the enzyme secretion by puromycin may be due to the detachment of the ribosomes from cytoplasmic membranes by disturbing the nascent polypeptide synthesis. Further evidence for confirming this was that the detachment was increased in 50 mM of magnesium ion because the extracellular $\alpha$-amylase activity was decreased more under this condition. If the cells were treated with trypsin combinated with Iysozyme, the extracellular $\alpha$-amylase activity from the cultured medium was reduced markedly, however, the activity from the cells treated with trypsin only was not reduced. This means that the nascent polypeptides protruding from the cytoplasmic membrane were sensitive to the trypsin digestion, whereas the matured ones were not. Therefore, the protruding polypeptides from the cytoplasmic membranes may be truncated by trypsin before forming their final tertiary structures by folding in the cell wall layer.

• YAKHAK HOEJI
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• v.35 no.1
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• pp.30-37
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• 1991

Streptomyces actuosus DMCJ-49 and Streptomyces minoensis DMCJ-144 produce the .alpha.-amylase inhibitor. Inerspecific protoplast fusion technique was used to increase the productivity of .alpha.-amylase inhibitor. Four auxotrophic mutants were obtained respectively from two strains by N-methyl-N'-nitor-N-nitrosoguanidine(3mg/ml) treatment. The optimum conditions for the protoplast formation of Streptomyces actuosus DMCJ-49 ade was as follows; 1.2% w/v of glycine, 3mg/ml of lysozyme, and 30 min of lysozyme treatment followed by 36 hr. incubation in the protop-last formation medium. In case of DMCJ-144-his those were 1.2%w/v, 3 mg/ml, 30 minutes and 60 hours, respectively. Regeneration was accomplished with hypertonic soft agar medium that contained 0.4M sucrose, 20mM CaCl$_2$, 50 mM MgCl$_2$ and low levels of phosphate. Fusion of protoplasts carrying different auxotrophic markers was achieved by treatment with polyethylene glycol. The optimum concentration of polyethylene glycol 1450 for the production of recombinants was 40%w/v. When the protoplasts was treated with 40% polyethylene glycol for 30 minutes, the frequency of recombinants was 6.5$\times$$10^{-3}$ and the $\alpha$-amylase inhibition activity of $ade^-his^-$ No. 4, which is the fusant with the most improved activity increased from 33 to 125 I.U./ml.

• Journal of environmental and Sanitary engineering
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• v.23 no.1
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• pp.25-31
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• 2008

A bacterial strain, Bacillus megaterium L-49 has been isolated and identified that produces alkaline ${\alpha}$-amylase. The cell is ellipsoidal, about $1.0-1.2{\times}3.0-3.6{\mu}m$ in diameter, Gram-positive, motile, and central partial central. Growth occurs in media containing 7% of NaCl. This strain could utilize D-glucose, lactose, xylose, sucrose, mannose, and maltose, and but it does not utilize D-fructose, and glycogen. Among the various concentrations of saturated ammonium sulfate, the retractation ratio in range of 70 to 100% was about 93%. However, in the case of acetone, it was about 98.7%. EDTA has activating effect and Ca2+ has no effect on alkaline ${\alpha}$-amylase activity. The alkaline ${\alpha}$-amylase has low thermal stability. The optimal temperature for reaction is $50^{\circ}C$. The alkaline ${\alpha}$-amylase activity maintained stabilizing at pH 6-11 and the optimal pH for reaction was 9-10.

• Journal of Food Hygiene and Safety
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• v.30 no.4
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• pp.359-365
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• 2015

The purpose of this study was to investigate the contents of sugars and ${\alpha}$-amylase and ${\beta}$-amylase activities in 98 specimen with enzyme foods and enzyme-shaped foods (the other processed foods, beverage bases, fermented drinks, liquid teas). The ${\alpha}$-amylase activity in enzyme foods and the other processed foods were ranged 4.9~53,854.6 U/g and 2.9~1,182.7 U/g, respectively, there was a big difference in the same type. The ${\alpha}$-amylase activity of the fermented products (beverage bases, fermented drinks, liquid teas) were ranged 0.1~1.7 U/g. The average of ${\beta}$-amylase activity in enzyme foods, the other processed foods, the fermented products were found 126.0 U/g, 5.6 U/g and 10.5 U/g, respectively, enzyme-shaped foods were a lot lower than enzyme foods. Total contents of sugars were average 22.4 g/100 g in enzyme foods, 14.8 g/100 g in the other processed foods, 46.9 g/100 g in beverage bases, 41.1 g/100 g in fermented drinks, 39.5 g/100 g in liquid teas, total contents of sugars appeared high amount in the fermented products. Correlations between ${\alpha}$-amylase activity and lactose content was statistically significant in enzyme foods (r = 0.644) and it was strong in the other processed foods (r = 0.903). Correlations between ${\beta}$-amylase activity and lactose content was statistically significant in enzyme foods (r = 0.648) and it was strong in the other processed foods (r = 0.757). There was a significant relationship between ${\alpha}$-amylase and ${\beta}$-amylase activities in enzyme foods and the other processed foods (r = 0.869, r = 0.760). That is, it was found that also the proportional relationship established among the ${\alpha}$-amylase activity, ${\beta}$-amylase activity.