• Journal of Microbiology and Biotechnology
• /
• v.29 no.3
• /
• pp.357-366
• /
• 2019

We first confirmed the involvement of MalQ (4-${\alpha}$-glucanotransferase) in Escherichia coli glycogen breakdown by both in vitro and in vivo assays. In vivo tests of the knock-out mutant, ${\Delta}malQ$, showed that glycogen slowly decreased after the stationary phase compared to the wild-type strain, indicating the involvement of MalQ in glycogen degradation. In vitro assays incubated glycogen-mimic substrate, branched cyclodextrin (maltotetraosyl-${\beta}$-CD: G4-${\beta}$-CD) and glycogen phosphorylase (GlgP)-limit dextrin with a set of variable combinations of E. coli enzymes, including GlgX (debranching enzyme), MalP (maltodextrin phosphorylase), GlgP and MalQ. In the absence of GlgP, the reaction of MalP, GlgX and MalQ on substrates produced glucose-1-P (glc-1-P) 3-fold faster than without MalQ. The results revealed that MalQ led to disproportionate G4 released from GlgP-limit dextrin to another acceptor, G4, which is phosphorylated by MalP. In contrast, in the absence of MalP, the reaction of GlgX, GlgP and MalQ resulted in a 1.6-fold increased production of glc-1-P than without MalQ. The result indicated that the G4-branch chains of GlgP-limit dextrin are released by GlgX hydrolysis, and then MalQ transfers the resultant G4 either to another branch chain or another G4 that can immediately be phosphorylated into glc-1-P by GlgP. Thus, we propose a model of two possible MalQ-involved pathways in glycogen degradation. The operon structure of MalP-defecting enterobacteria strongly supports the involvement of MalQ and GlgP as alternative pathways in glycogen degradation.

• ALGAE
• /
• v.19 no.2
• /
• pp.145-148
• /
• 2004

As a result of the 2-year monthly monitoring of the phytoplankton community at 3 stations in Mankyeong Estuary, Korea, we learned that cyan bacterial species of the genus Anabaena occurred at most sampling points with huge salinity differences (0.1-32.5 psu). We isolated several clones of Anabaena spp. from the monitoring stations, and screen out two euryhaline and nitrogen-fixing Anabaena clones, CB-MAL21 and CB-MAL22. The two clones were grown under various environmental gradients such as temperature (20, 30, 35 and 40$^{\circ}C$), salinity (0, 2, 5, 15 and 30psu), and $PO_4^{3-}$-P concentration (0, 1.6, 8.0, 40 and 200 ${\mu}M$M). Growth of CB-MAL21 and CB-MAL22 was measured by daily monitoring of chlorophyll fluorescence from each experimental culture for more than three serial transfers. Both the two experimental clones did not grow at 0psu. Maximal growth rates of the two clones were markedly reduced at lower $PO_4^{3-}$-P concentrations showing negligible growth at 0 and 1.6 ${\mu}M$M. However, growth of CB-MAL21 was not affected by low $NO_3^--$ concentration in culture media, showing the nitrogen-fixing ability. Maximum biomass yields of the two clones decreased dramatically at 35 and 40$^{\circ}C$. Optimal growth conditions for the two experimental clones were determined to be 20-30$^{\circ}C$, 40 ${\mu}M$M $PO_4^{3-}$-P, and wide salinity range from 5.0 to over 30psu. Best growth of CB-MAL21 was shown at (20$^{\circ}C$-15psu), which is less saline and cooler condition than those (i.e., 30$^{\circ}C$-30psu) for the best growth of CB-MAL22. The euryhaline and nitrogen-fixing CB-MAL21 strain thus can be a candidate laboratory culture for the future cyan bacterial marine biotechnology in temperate coastal waters.

• Journal of the East Asian Society of Dietary Life
• /
• v.15 no.6
• /
• pp.766-772
• /
• 2005

The purpose of this study is to find out the optimal mixing ratios of Mal-Cha for the preparation of Jeung-Pyun through sensory and mechanical tests. The proximate composition of Mal-Cha were $5.46\pm0.15\%$ of moisture, $4.43\pm0.11\%$ of total nitrogen, $7.52\pm0.21\%$ of crude lipid, $8.74\%$ of crude fiber, $8.51\pm0.09\%$ of ash. Overall quality of Jeung-Pyun with $1.5\%$ Mal-Cha was the worst compare with 0, 0.5 and $1.0\%$ ones(p<0.05). Especially, $1.0\%$ Mal-Cha Jeung-Pyun showed the best overall quality. But the sweetness, sourness, flavor, hardness, and moistnes were not significantly different among all the treatments. Acceptabilities of 0.5 and $1.0\%$ Mal-Cha Jeung-Pyuns were not significantly different from that of the control in their sensory and mechanical qualities. Total color difference increased with the amount of Mal-Cha significantly(p<0.001).

• Journal of Microbiology and Biotechnology
• /
• v.15 no.3
• /
• pp.616-625
• /
• 2005

It is likely that maltose could provide a good substrate for the bacteria in the intestine, when the pathogenic bacteria invade and colonize in human gut. For better understanding of this organism's maltose metabolism, a mutant that was not able to grow with maltose as a sole carbon source was screened from a library of mutants constructed by a random transposon mutagenesis. By a transposon-tagging method, malPQ genes encoding a maltodextrin phosphorylase and a 4-${\alpha}$-glucanotransferase, were identified and cloned from Vibrio vulnificus. The deduced amino acid sequences of malPQ from V. vulnificus were 48 to $91\%$ similar to those of MalP and MalQ reported from other Enterobacteriaceae. Functions of malPQ genes were assessed by the construction of mutants whose malPQ genes were inactivated by allelic exchanges. When maltose was used as the sole carbon source, neither malP nor malQ mutant was able to grow to a substantial level, revealing that the MalP and MalQ are the only enzymes for metabolic utilization of maltose. The malQ mutant exhibited decreased adherence toward intestinal epithelial cells in vitro, but there was no difference in the $LD_{50}s$ of the wild-type and the malQ mutant in mice. Therefore, it appears that MalQ is less important in the pathogenesis of V. vulnificus than would have been predicted by considering maltose as a most common sugar in the intestine, but not completely dispensable for virulence in mice.

• Journal of Environmental Science International
• /
• v.3 no.2
• /
• pp.157-164
• /
• 1994

Various antimicrobial agents are widely used for the purpose of antimicrobial process. We investigated antimicrobial activity and reduction efficiency of mal-ordour by the diphenyl ether compound (2,4,4'- trichloro -2'- hydroxy diphenyl ether) against Sraphylocom aureus(S.aureus and Proton vulgaris(p.vulgaris causing the mal-ordour, Especially, the diphenyl ether compound is not restricted to the regulation of water-contamination. In this research, we found that the optimum concentration of diphenyl ether compound was 1.5w% for both strains and antimicrobial expressions were c0.38t= 2.56 for S.aureus, c0.38t=2.67 for P.vulgaris. We found also that -OH group played the role of antimicrobial functional group. Lastly, reduction effect of mal-ordour was more than 90% for both strain at the optimum conditions. Key Words : antimicrobial agents, antimicrobial activity, reduction effect of mal-ordour, antimicrobial expression, antimicrobial functional group.

• Journal of Microbiology and Biotechnology
• /
• v.24 no.11
• /
• pp.1503-1509
• /
• 2014

With the purpose of facilitating the process of stable strain generation, a shuttle vector for integration of genes via a double recombination event into two ectopic sites on the Sulfolobus acidocaldarius chromosome was constructed. The novel chromosomal integration and expression vector pINEX contains a pyrE gene from S. solfataricus P2 ($pyrE_{sso}$) as an auxotrophic selection marker, a multiple cloning site with histidine tag, the internal sequences of malE and malG for homologous recombination, and the entire region of pGEM-T vector, except for the multiple cloning region, for propagation in E. coli. For stable expression of the target gene, an ${\alpha}$-glucosidase-producing strain of S. acidocaldarius was generated employing this vector. The malA gene (saci_1160) encoding an ${\alpha}$-glucosidase from S. acidocaldarius fused with the glutamate dehydrogenase ($gdhA_{saci}$) promoter and leader sequence was ligated to pINEX to generate pINEX_malA. Using the "pop-in" and "pop-out" method, the malA gene was inserted into the genome of MR31 and correct insertion was verified by colony PCR and sequencing. This strain was grown in YT medium without uracil and purified by His-tag affinity chromatography. The ${\alpha}$-glucosidase activity was confirmed by the hydrolysis of $pNP{\alpha}G$. The pINEX vector should be applicable in delineating gene functions in this organism.

• Journal of Pharmaceutical Investigation
• /
• v.8 no.1
• /
• pp.1-5
• /
• 1978

Drug interaction of a new antibiotic, methampicillin lysinate (MAL) with nine drugs were investigated using four species of gram positive and gram negative bacteria. The experimental results were as follows: 1. MIC of MAL were found to be decreased against E. coil when combined with mefenamic acid, probenecid, aluminium hydroxide gel or corticosteroids. The other drugs did not affect MIC of MAL against the same bacteria. 2. MIC of MAL were found to be increased against Staphylococcus aureus ATCC 6538-P, 9441 when combined with mefenamic acid, aluminum hydroxide gel or dexamethasone acetate. The other drugs did not affect MIC of MAL against the same bacteria. 3. MIC of MAL were found to be increased against Shigella dysenteriae when either of the nine drugs was combined. 4. MIC of MAL were found to be increased approximately 2.5 times when combined with Streptokinase-Streptodornase or hydrocortisone and to be decreased approximately 2 times when combined with probenecid or dexamethasone against Salmonella typhi(type 2). It seems the other drugs do not affect the MIC of MAL against the same bacteria.

• Microbiology and Biotechnology Letters
• /
• v.46 no.1
• /
• pp.29-39
• /
• 2018

Vibrio vulnificus needs various responsive mechanisms to survive and transmit successfully in alternative niches of human and marine environments, and to ensure the acquisition of steady energy supply to facilitate such unique life style. The bacterium had genetic constitution very different from that of Escherichia coli regarding metabolism of glycogen, a major energy reserve. V. vulnificus accumulated more glycogen than other bacteria and at various levels according to culture medium and carbon source supplied in excess. Glycogen was accumulated to the highest level in Luria-Bertani (3.08 mg/mg protein) and heart infusion (4.30 mg/mg protein) complex media supplemented with 1% (w/v) maltodextrin at 3 h into the stationary phase. Regarding effect of carbon source, more glycogen was accumulated when maltodextrin (2.34 mg/mg protein) was added than when glucose or maltose (0.78.1-14 mg/mg protein) was added as an excessive carbon source to M9 minimal medium, suggesting that maltodextrin metabolism might affect glycogen metabolism very closely. These results were supported by the analysis using the malP (encoding a maltodextrin phosphorylase) and malQ (encoding a 4-${\alpha}$-glucanotransferase) mutants, which accumulated much less glycogen than wild type when either glucose or maltodextrin was supplied as an excessive carbon source, but at different levels (3.1-80.3% of wild type glycogen). Therefore, multiple pathways for glycogen metabolism were likely to function in V. vulnificus and that responding to maltodextrin might be more efficient in synthesizing glycogen. All of the glycogen samples from 3 V. vulnificus strains under various conditions showed a narrow side chain length distribution with short chains (G4-G6) as major ones. Not only the comparatively large accumulation volume but also the structure of glycogen in V. vulnificus, compared to other bacteria, may explain durability of the bacterium in external environment.

• Journal of Industrial Technology
• /
• v.28 no.B
• /
• pp.59-63
• /
• 2008

Rapid production of therapeutic proteins such as angiostatin and endostatin angiogenic inhibititors has been highly demanded for cancer treatment. In this regard, recombinant human angiostatin and endostatin were successfully expressed as soluble forms by maltose binding protein (MBP)-mediated fusion expression in Escherichia coli. PCR amplified, angiostatin and endostatin genes from human placenta cDNA library were inserted into an expression vector pMAL-c2e to construct prokaryotic expression vectors, pMAL-c2e/AS and pMAL-c2e/ES, respectively. Recombinant angiostatin and endostatin were efficiently expressed in E. coli origami (DE3) after IPTG induction and protein expression were confirmed by SDS-PAGE analyses. The expressed recombinant proteins were purified near homogenity using an amylose affinty column chromatography. In contrast that previous E. coli expressions were all insoluble, our results first time demonstrated that MBP fused human angiostatin and endostatin were soluble in E. coli.

• Advances in nano research
• /
• v.11 no.6
• /
• pp.667-678
• /
• 2021

Multiwalled carbon nanotubes (MWCNTs) were first oxidized (O-CNTs) to introduce carboxylic group and then further functionalized (F-CNTs) with m-phenylenediamine, which was confirmed by FTIR and SEM. It was used as an effective adsorbent for the adsorptive removal of diclofenac drug from water. Under optimum conditions of pH 6, stirring speed 600 rpm, the maximum adsorption capacity obtained was 532 mg g^-1 which is superior to the values reported in literature. The adsorption was quite rapid as 25 mg L^-1 drug solution was adsorbed in only 3 minutes of contact time with 10 mg of adsorbent dose. The adsorption kinetics and isotherms were studied using various models to evaluate the adsorption process. The results showed that the data best fit in kinetics pseudo-second order and Langmuir isotherm model. Furthermore, the oxidized and functionalized MWCNTs were applied on gram-negative Escherichia coli and gram-positive Staphylococcus aureus using agar disc diffusion assay to validate their anti-microbial activity. Results were unique as both oxidized and functionalized MWCNTs were equally active against both E. coli and S. aureus. The newly synthesized F-CNTs have great potential in water treatment, with their dual action of removing drug and pathogens from water, makes it potential applicant to save environment.