• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.990-996
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• 2008

In a previous study, we found an antifungal effect on human pathogenic fungi by the cell-penetrating peptide Tat (47-58) derived from HIV-1. Tat (47-58) immediately entered into the fungal nucleus and affected some physiological changes on the intracellular condition. In this study, Tat (47-58) showed a broad spectrum of antibacterial activity against pathogenic bacteria including bacterial clinical isolates. To improve resistance against proteases for use in vivo, we synthesized an analog of Tat (47-58) by substituting the L-amino acid for the D-amino acid. The D-enantiomer of Tat (47-58) also exhibited a broad spectrum of antibacterial activity at almost the same level of L-Tat (47-58) concentration. Unlike L-Tat (47-58), D-Tat (47-58) showed a significant proteolytic resistance against all proteases tested and antimicrobial activities in the presence of trypsin. Moreover, D-Tat (47-58) inhibited MRSA infection in human HeLa cells whereas L-Tat (47-58) partially allowed MRSA infection, and the results were due to the proteolytic resistance of D-Tat (47-58).

• Journal of Dairy Science and Biotechnology
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• v.40 no.2
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• pp.86-91
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• 2022

Chryseobacterium mulctrae KACC 21234^T is a novel species isolated from raw bovine milk. Psychrotrophic bacteria are considered contaminants and are hypothesized to originate from the environment. In this investigation, the C. mulctrae KACC 21234^T genome was determined to be 4,868,651 bp long and assembled into four contigs with a G+C ratio of 33.8%. In silico genomic analyses revealed the presence of genes encoding proteases (endopeptidase Clp, oligopeptidase b, carboxypeptidase) and lipases (phospholipase A(2), phospholipase C, acylglycerol lipase) that can catalyze the degradation of the proteins and lipids in milk, causing its quality to deteriorate. Additionally, antimicrobial resistance and putative bacteriocin genes were detected, potentially intensifying the pathogenicity of the strain. The genomic evidence presented highlights the need for improved screening protocols to minimize the potential contamination of milk by proteolytic and lipolytic psychrotrophic bacteria.

• Microbiology and Biotechnology Letters
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• v.21 no.4
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• pp.293-298
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• 1993

The ppage resistance mechanism of Lactococcus lactis subsp. cremoris ATCC 11602-A1 was investigated. When parent and A1 were incubated at 30 and 40$^{\circ}C$, A1 grew well and multiplication of phage(MOI=1)on A1 slightly occurred at 40$^{\circ}C$ in contrast with parent. There was a great difference of proteolytic activity between parent and A1, irrespective of the temperature. As a result of ADS treatment oon culture broth, survival rate of A1 was 27% at the lethal concentration of parent and adsorption rate of phage was increased to 95~97%, which was considered to come from the exposure of phage receptor site masked by an unknown component. These results suggest that acridine orange (AO) treatment leads to the modification of cell wall, conferring resistance to high temperature and lytic phage. No change in plasmid profiles of A1 at 30 and 40$^{\circ}C$ were found, which suggests that plasmid is not relative to temperature-resistance of A1.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.161-168
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• 2010

In this study, the metabolic activities of five strains of Pediococcus spp., in terms of the quantities they produced of lactic acid, hydrogen peroxide, exopolysaccharides, and proteolytic activity, were determined. Lactic acid levels produced by these strains were found to be in the range of 2.5-5.6 mg/ml. All strains produced hydrogen peroxide. The P. pentosaceus Z13P strain produced the maximum amount (0.25 mg/ml) of proteolytic activity. Exopolysaccharide (EPS) production by the Pediococcus strains during growth in MRS (de Man, Rogosa, and Sharpe) medium was in the range 25-64 mg/l. The susceptibility of 10 different antibiotics against these strains was also tested. All strains were found to be resistant to amoxicillin, gentamicin, and vancomycin. Antimicrobial effects of the Pediococcus spp. on pathogens were also determined by an agar diffusion method. All of the strains were able to inhibit L. monocytogenes. The tolerance of the strains to low pH, their resistance to bile salts of strains, and their abilities to autoaggregate and coaggregate with L. monocytogenes were also evaluated.

• YAKHAK HOEJI
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• v.51 no.3
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• pp.199-205
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• 2007

Thermostable asparaginase was purified to homogeneity from mesophilic Strepfomyces lincolnensis M-20 by 30${\sim}$70% ammonium sulfate precipitation and asparagine-Sepharose CL 6B affinity column chromatography, The apparent molecular mass of L-asparaginase by SDS-PAGE was found to be 47 kDa, whereas by its mobility on Sephacryl S-300 column was around 180 kDa, indicating that the enzyme at the native stage acts as tetramer, The purified enzyme showed a single band on acrylamide gel electrophoresis. The optimum pH and temperature were pH 9.5 and 55${\circ}$C, respectively. Chemical modification experiments of purified asparagines implied the existence cystein residue located at or near active site. Purified asparaginase retained the 85% of the initial activity after incubation at 90${\circ}$C for 30 min. A correlation between themostability and resistance to proteolysis of commercial asparaginase and purified asparaginase from Strepfomyces lincolnensis M-20 was investigated. Purified thermostable asparaginase was resistant to trypsin and chymotrypsin treatment, while the commercial asparaginase was not themostable and was susceptible to proteolytic treatment with trypsin and chymotrypsin.

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.317-321
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• 1990

The broad-host plasmid PAM $\beta_1$ of Streptococcus faecalis DS 5 which codes for erythromycin resistance and lactose utilization was transferred into L. casei M-3 (lac-mutant) by conjugation, but was not transferred by protoplast fusion and protoplast transformation. For conjugal transfer of plasmid PAM $\beta_1$ the method of membrane filter mating was more efficient than that of agar surface mating. The rate of acid production of transconjugant C-1, C-3 was similar to L. casei YIT 9018. The proteolytic activity of transconjugant C-3 was increased 20% higher than that of wild type. Plasmid PAM $\beta_1$ was detected by a11 of the transconjugants. The transconjugants expressed lactose ulitization and erythromycin resistance.

• Korean Journal of Animal Reproduction
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• v.17 no.2
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• pp.93-101
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• 1993

These experiments were carried out to investigate whether zona hardening affect the efficiency of in vitro fertilization in mouse oocytes. The soluble properties for zona pellucida of oocytes matured in vivo, aged oocytes, and ovarian oocytes matured in vitro have been analyzed with proteolytic enzyme, 3mg/ml of $\alpha$-chymotrypsin. The mean solubility(t50) for the zona of unfertilized oocytes, oocytes not fertilized at the first inseminati and in vitro produced zygotes were 10.1, 20.3 and 32.3min., respectively. The t50 for zona lysis of fertilized oocytes was significantly difference than those observed for unfertilized oocytes and oocytes not fertilized at the first insemination(P<0.01). In addition, the t50 of zona in ovulated oocytes with and without cumulus cells incubated for 0, 3, 6, 9 and 12 hr in vitro, t50 were 13.9, 11.1, 20.7 and 28.0min., and 22.3, 21.0, 30.0 and 33.5min., respectively. In these experiments, the zona pellucida showed a gradual increase in resistance to dissolution by $\alpha$-chyjotrypsin with in vitro aging for more than 6 hrs. This effect was greater in cumulus-free as compared to cumulus-intact oocytes. Finally, in cumulus-intact and cumulus-free ovarian oocytes matured for 0, 5, 10 and 15 hr in vitro the t50 of zona pellucida were 3.0, 10.6, 18.4 and 24.5 min., and 3.0, 14.0, 26.2 and 32.0 min., respectively. Clear differences in solubility between the zona pellucida of oocytes matured in vivo and in vitro. This data were found suggest that under in vitro conditions there is a gradual change in the soluble properties of the zona pellucida, particularly in the absence of the cumulus cells.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.666-674
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• 2016

The bacterial strains were screened as potential starters for fermenting low-salt doenjang (a Korean traditional fermented soybean paste) using Korean doenjang based on proteolytic and antipathogenic activities under 6.5-7.5% NaCl conditions. Phylogenetic analysis based on 16S rRNA gene sequences showed that they all belonged to the genus Bacillus. Proteolytic and antipathogenic activities against Escherichia coli, Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, and Aspergillus flavus, as well as fibrinolytic, amylase, and cellulase activities of the 10 strains were quantitatively evaluated. Of these, strains D2-2, JJ-D34, and D12-5 were selected, based on their activities. The functional, phenotypic, and safety-related characteristics of these three strains were additionally investigated and strains D2-2 and D12-5, which lacked antibiotic resistance, were finally selected. Strains D2-2 and D12-5 produced poly-γ-glutamic acid and showed various enzyme activities, including α-glucosidase and β-glucosidase. Growth properties of strains D2-2 and D12-5 included wide temperature and pH ranges, growth in up to 16% NaCl, and weak anaerobic growth, suggesting that they facilitate low-salt doenjang fermentation. Strains D2-2 and D12-5 were not hemolytic, carried no toxin genes, and did not produce biogenic amines. These results suggest that strains D2-2 and D12-5 can serve as appropriate starter cultures for fermenting low-salt doenjang with high quality and safety.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.348-355
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• 2013

Squid ink was added to the salt fermented squid by 2% or 4% of concentration and ripened at $10^{\circ}C$ for 8 weeks and at $20^{\circ}C$ for 32days. The effects of the squid ink on the amino nitrogen and muscle protein of salt fermented squid were investigated. The results are as follows; As the salt concentration was decreased and the fermentation temperature raised, amino nitrogen in the salt fermented squid without addition of the squid ink was significantly increased to the latter stage of the ripening and hence fermentations were enhanced. From the change of the protein in the squid muscle in the experiments, dissolution of the myosin heavy chain took place conspicuously in the early stage of the ripening while actin was rarely changed which resulted in the strong resistance to protease. The amino nitrogen content in the salt fermented squid addition of the squid ink has increased to the latter part of the ripening but the range was smaller than no treatment groups. The protein in squid muscle, especially the myosin heavy chain was remarkably dissolved in the middle of the ripening whereas the squid ink added groups of high salt concentration and low temperature showed the tendency of slow proteolysis.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.313.3-314
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• 2002

Cyclooxygenase-2 (COX-2) is an inducible enzyme expressed in response to a variety of cytokines and other proinflammatory stimuli. It has been known that aberrant up-regulation of COX-2 is associated with resistance to apoptosis. Contrary to the above notion. treatment of MCF10A-ras cells with the anti-tumor agent ET -18-O-$CH_3$ caused increased expression of COX-2 and its mRNA transcript. while inducing apoptosis as revealed by proteolytic cleavage of poly(ADP-ribose)polymerase. caspase-3 activation, and positive TUNEL staining. (omitted)