• Asian-Australasian Journal of Animal Sciences
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• v.9 no.1
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• pp.27-30
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• 1996

One thousand eight hundreds and twenty two samples of raw milk were detected for antibiotic residues using Bacillus subtilis ATTCC 6633, B. stearothermophilus var. calidolactis C 593 and Micrococcus luteus ATCC 9341 as test organisms, were carried out from July 1991 through June 1992. Apparent antibiotic residues were found through out the study period, except in January. The detection rate varied from 0.7% in March and May to 11% in April. One hundred and thirty six (72%) samples of the 187 screening positive samples were considered to contain only the indigenous antimicrobial agents. Of the total, 51 (2.8%) samples were positive for antibiotic residues. Among the tested organisms, B. stearothermophilus var. calidolactis was the most sensitive organism in detection of the antibiotic residues.

• Microbiology and Biotechnology Letters
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• v.23 no.2
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• pp.138-144
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• 1995

The cDNA, encoding human lysozyme (HLY) which was isolated from a human placenta cDNA library, has been well characterized (Yoshimura et al., 1988). Based on the communication, we have prepared an artificial HLY gene from chemically synthesized 38-oligomer with high codon usage in Saccharomyces cerevisiae. For directing the synthesis and secretion of HLY in S. cerevisiae, an expression vector, pHKl was constructed by inserting the HLY gene, containing a synthetic HLY secretion signal sequence, between the yeast GAP promoter and PH05 terminator. From a lysoplate assay, we have confirmed an yeast transformant harboring a pHK1 which makes a clearing zone on the overlayed Micrococcus luteus. This result means a chemically synthesized HLY gene which was normally expressed and secreted in yeast.

• Archives of Pharmacal Research
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• v.12 no.3
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• pp.176-180
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• 1989

Four bacterial strains having inducible resistance to erythromycin were isolated from soil samples in Korea and characterized. MLS inducibility was checked in each strain. Cloning of inducible resistance gene(s) has been tried. Four isolates were identified as B. anthracis, Micrococcus luteus, Streptococcus faecium and B. licheniformis, in which erythromycin, oleandomycin, cirramycin and carbomycin acted as resistance inducers respectively. The resistance gene cloned from B, licheniformis 597 strain using pBS 42 vector was found to have a 3.2 kb insert.

• Natural Product Sciences
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• v.9 no.3
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• pp.154-157
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• 2003

In the present study, the roots of Sesbania grandiflora L. Poiret (Papilionaceae) were successively extracted with petroleum ether (PE), chloroform (CE), methanol (ME) and water (AE) by soxhlet extraction. The extracts were vacuum dried and screened for analgesic, antidiarrhoeal, antibacterial (Staphylococcus epidermidis, Staphylococcus aureus, Micrococcus luteus, Bacillus cereus, and Klebsiella pneumonia) and antifungal (Candida albicans and Aspergillus niger) activity. All the extracts exhibited potent, dose dependant (40 and 80 mg/kg) and significant analgesic and antidiarrhoeal activity in the order of AE>PE>CE>ME and ME>PE>AE>CE respectively. AE at the experimental dose was found to exhibit more potent analgesic activity than standard drug. All the extracts exhibited significant antibacterial $(100\;{\mu}g/ml)$ and antifungal activity $(50\;and\;100\;{\mu}g/ml)$. ME exhibited the most potent antibacterial activity.

• Korean Journal of Microbiology
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• v.37 no.1
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• pp.1-8
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• 2001

Spiders are carnivores that prey upon insects and other small arthropods through digestion of food outside the body. Although spider poison may contain proteolytic enzymes, these are thought to play an insignificant role in actual digestion. The source of active proteolytic enzymes can be either the digestive tract cells of spider, or natural microbial flora in the digestive tract of spider. In this study, digestive tracts from the spider, Nephila clavata, were screened for bacteria that have protease or lipase activity. A total of $10^3-10^5$ CFU was recovered from a spider and more than 90% of them showed protease and lipase activity respectively. Of the microbial isolates, 63.3% showed protease or lipase activity, and 50% of these showed both protease and lipase activity. Some of the isolates were characterized using a battery of chemical, phenotypic and genotypic methods. Eleven Gram negative bacteriaa (Acinetobacter calcoaceticus, A. haemolyticus, Alcaligenes faecalis, Cedecea davisae, C. neteri, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas fluorescens, Serratia marcescens, Stenotrophomonas maltophilia, Suttonella indologenes) and 11 Gram positive bacteria (Bacillus cereus, B. coagulans, B. pasteurii, B. thuringiensis, Cellulomonas flavigena, Corynebacterium martruchotii, Enterococcus durans, E. faecalis, Micrococcus luteus, Staphylococcus hominis, S. sciuri) were identified.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.400-406
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• 1997

Chemical composition and antimicrobial activity of Houttuynia cordata Thunb. were investigated to develop a natural food preservative from it. Aspartic acid, glutamic acid, glycine and arginine were major amino acids of Houttuynia cordata Thunb., but were present in a trace amount. Free sugars were composed of glucose, fructose, sucrose and maltose and major fatty acids were linolenic acid, linoleic acid, oleic acid, and palmitic acid. Mineral elements were potassium, calcium, magnesium, iron, zinc, and copper. Antimicrobial activities were shown in acidic, neutral and phenolic fraction of Houttuynia cordata Thunb., but not in basic fraction. Among the four fractions, neutral fraction showed the strongest antimicrobial activities against microorganisms tested, such as Pseudomnas aeruginosa, Micrococcus luteus, Bacillus subtilis, Aspergillus parasiticus and Aspergillus flavus. Minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) of the neutral fraction varied according to microoganisms tested. The lowest values of MIC (0.0075 g eq./mL) and MLC (0.10 g eq./mL) were obtained from Pseudomonas aeruginosa.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.2
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• pp.193-204
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• 1984

The enzymatic properties of the alkaline AL-protease, which had been prepared from the crude zymolyase of Arthrobzoter luteus, was investigated together with its active amino acid residue. Complete inactivaton of the proteolytic activity of AL-protease by either DFP or PMSF was simultaneously accompanied by the loss of its lytic effect on the lysis of yeast cell wall. In the reaction, AL-protease showed the pattern of inactivation to decrease very slowly, as compared to that of chymotrypsin, and that enzyme and DFP were found to react with a molar ratio of 1 : 1. The preparation of AL-protease exhibited no hydrolytic activity in any substrates of polysaccharases, playing a significant role in the lysis of yeast cell wall. The optimum pH and temperature of AL-protease was pH 10.5 and $65^{\circ}C$, respectively. It also showed stability in the pH range from 5 to 11 and at the temperature below $65^{\circ}C$. Through the identification of the amino acid residue in the active site of the $^{32}P$-diisopropylph-osphorylated(DIP) AL-protease modified specifically with $^{32}P$-labeled DFP, AL-protease was found to be a DFP-sensitive which has a mole of active serine residue involved in its proteolytic activity per mole of the enzyme.

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.469-474
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• 2001

The actinomycete strain AMLK-335 was antagonistic to vancomycin-resistant enterococci (VRE). Based on the diaminopimelic acid (DAP) type, and morphological and physiological characteristics revealed by scanning electron microscopy (SEM), AMLK-335 was confirmed to belong to the genus Streptomyces. Analysis of the 16S rDNA nucleotide sequences found AMLK-335 to have a relationship with Streptomyces platensis. The production of antibiotic from this strain was most favorable when cultured on glucose, polypeptone, yeast extract (PY) medium for 6 days at $27^{\circ}$. The antibiotic was identified as cyclo(L-phenylalanyl-L-prolyl) by comparing ti with the reported MS and NMR spectral data. Cyclo(phe-pro) from the PY cultures of AMLK-335 was most effective (K-98-258). Futhermore, cyclo(phe-pro) had antimicrobial activity against Bacillus subtilis, Microcuccs luteus, Staphylococcus aureus, and Saccharomyces cerevisiae, but it wa ineffective against Candida albicans, Streptomyces murinus, and Aspergillus niger.

• Natural Product Sciences
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• v.20 no.3
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• pp.202-205
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• 2014

Three compounds including 7,7-bis(3-indolyl)-p-cresol (1), cyclo-(S-Pro-R-Leu) (2) and cyclo-(S-Pro-R-Val) (3) were isolated from the strain of Bacillus megaterium LC derived from the marine sponge Haliclona oculata. All the isolated compounds showed antimicrobial activity at MIC values ranging from 0.005 to $5{\mu}g/mL$ against Gram-negative bacteria Vibrio vulnificus and V. parahaemolyticus, gram-positive bacteria Bacillus cereus and Micrococcus luteus, and the dermatophyte Trichophyton mentagrophytes. The results suggested that these compounds might have potential to be developed as agents treating dermatosis and controlling vibriosis in aquaculture.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1228-1236
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• 1997

Lactobacillus strains were isolated from volunteer's feces, including from newly-born infants and adults in their 20's, by using differential MRS-BPB plates. Total 56 presumptive Lactobacillus strains were isolated and the bacteriocin productions by the isolates were examined by agar diffusion method. Six bacteriocin-producing strains were confirmed. Among them, two isolates, HU-1 and H22-3, showed the most outstanding antimicrobial activities, which were not affected by pH adjustments or catalase treatments of culture. HU-1 was originated from a two-years old boy and H22-3 was originated from a newly-born infant. HU-1 and H22-3 had the same morphology(short rod) when examined by scanning electron microscope, and the same biochemical traits including growth temperature range, salt tolerance and sugar-fermenting abilities. But the growth-inhibition spectrum and plasmid profiles of HU-1 and H22-3 were different. Both strains inhibited the growth of various Gram (+) microorganisms including Listeria monocytogenes. Micrococcus luteus, and Staphylococcus aureus in addition to many species of lactic acid bacteria, indicating the production of broad-spectrum bacteriocins. Bacteriocins produced by HU-1 and H22-3 were stable up to 90℃, 15 min heat treatments. Their activities were not affected by pepsin or trypsin treatments but destroyed by proteinaseK or pronase treatments.