• 환경생물
• /
• 제22권4호
• /
• pp.487-493
• /
• 2004

To investigate the antifungal activity related protein in pesticidal bacteria, a bacterial strain LTD was isolated from soil collected at Gimje in Jeonbuk province, Korea, and identified as Bacillus subtilis LTD based on a API50 CHB kit and 168 rDNA sequencing. It has an antifungal activity against 9 plant pathogenic fungi in a paper disc assay. The antifungal activity- deficient mutant, B. subtilis mLTD was induced at a 5 kGy dose of $^{60}Co$ gamma radiation. Using the two-dimensional electrophoresis and the matrix assisted laser desorption ionization time-of-flight mass spectrometry, the comparison analysis of proteins between the wild and mutant were performed. A major intracellular serine proteinase IspA (MW: 32.5 kDa), a NAD (P) H dehydrogenase (MW: 20.0 kDa), and a stage II sporulation protein AA, SpoIIAA (MW: 14.3kDa) were detected only in the B. subtilis LTD. These results suggested that the functions of these proteins found only in the B. subtilis LTD could. be closely related to the antifungal activity against plant pathogenic fungi.

• 대한한의진단학회지
• /
• 제15권1호
• /
• pp.47-54
• /
• 2011

In traditional Korean medicine, inspection of the tongue is an important method of making medical diagnoses and determining prognosis. We surveyed the fluorescence characteristics of the tongue coat in the ultraviolet light. The tongue coat comprises micro-organisms, blood metabolites, leukocytes from periodontal pockets, large amounts of desquamated epithelial cells released from the oral mucosa and different nutrients. In the ultraviolet light tissues of the oral cavity generally emit weak red or green fluorescence, which is not easily seen by the human eye, but is readily detected. This fluorescence has been proved to be due to the production of porphyrins by oral micro-organisms. While the composition of motile micro-organisms on the dorsum of the tongue is not constant, variations also occur persistingly in the fluorescence characteristics of the tongue coat. But because live bacteria contain a variety of intracellular biomolecules that have specific excitation and emission wavelength spectra characterizing their intrinsic fluorescence, the tongue coat emits fluorescence. the tongue itself, on the other hand, emits very weak or not fluorescence. In conclusion, we suggests that the uncoated tongue area be eliminated from the coated tongue area with the difference between the fluorescence characteristics of the tongue and that of the tongue coat.

• 한국미생물생명공학회:학술대회논문집
• /
• 한국미생물생명공학회 2000년도 Proceedings of 2000 KSAM International Symposium and Spring Meeting
• /
• pp.108-113
• /
• 2000

Freshwater borne bacteria transformed with luxAB-containing plasmid were optimized for the toxicity tests of various organic carbons and heavy metals. The EC$\sub$50/ values obtained from tests using the most sensitive bacterium to toxicants, YH9-RC, revealed to be much less than those from the Microtox$\^$/. In addition, some physiological characteristics of this bacterium under the toxic stress conditions such as potential bioluminescence, specific growth rate, and intracellular ATP contents, reproducibly and reliably correlated to the toxicity of the chemicals exposed. The higher concentrations of COD in wastewater samples, the lower EC$\sub$50/ values, therefore the developed toxicity test was found to be easily applicable to the toxicity test for wastewater samples and effluents. The conditions for constructing 384-multiwell plate containing freeze-dried bacterium were also optimized through the addition of 0.16 M trehalose before freeze-drying. Consequently, the advanced test system featuring a continuous measurement of the toxicity, an automated real-time monitoring of its results, and an alerting function was designed and constructed in combination with the microbiological, mechanical, and electronic compartment.

• Journal of Microbiology and Biotechnology
• /
• 제23권9호
• /
• pp.1304-1307
• /
• 2013

Growth of Microcystis aeruginosa could be inhibited significantly within 24 h by the extracellular substances prepared from Aeromonas sp. strain FM. During the treatment, the concentration of extracellular soluble carbohydrates increased significantly in algal culture. Morphological and ultrastructural changes in M. aeruginosa cells, including breakage of the cell surface, secretion of mucilage, and intracellular disorganization of thylakoids, were observed. HPLC-MS analysis showed that the extracellular substances of Aeromonas sp. strain FM were a mixture of free amino acids, tripeptides, and clavulanate. Among these, the algaelysis effects of lysine and clavulanate were confirmed.

• Journal of Microbiology and Biotechnology
• /
• 제12권1호
• /
• pp.31-38
• /
• 2002

Bacteria have evolved various types of resistance mechanism to toxic heavy metals, such as arsenic and antimony. An arsenical and antimonial resistant bacterium was isolated from a shallow creek draining a coal-mining area near Taebaek City, in Kangwon-Do, Korea. The isolated bacterium was identified and named as Pseudomonas sp. KM20 after biochemical and physiological studies were conducted. A plasmid was identified and its function was studied. Original cells harboring the plasmid were able to grow in the presence of 15 mM sodium arsenite, while the plasmid-cured (plasmidless) strain was sensitive to as little as 0.5 mM sodium arsenate. These results indicated that the plasmid of Pseudomonas sp. KM20 does indeed encode the arsenic resistance determinant. In growth experiments, prior exposure to 0.1 mM arsenate allowed immediate growth when they were challenged with 5 mM arsenate, 5 mM arsenite, or 0.1 mM antimonite. These results suggested that the arsenate, arsenite, and antimonite resistance determinants of Pseudomonas sp. KM20 plasmid were indeed inducible. When induced, plasmid-bearing resistance cells showed a decreased accumulation $of\;73^As$ and showed an enhanced efflux $of\;^73As$. These results suggested that plasmid encoded a transport system that extruded the toxic metalloids, resulting in the lowering of the intracellular concentration of toxic oxyanion. In a Southern blot study, hybridization with an E. coli R773 arsA-specific probe strongly suggested the absence of an arsA cistron in the plasmid-associated arsenical and antimonial resistance determinant of Pseudomonas sp. KM20.

• 한국미생물·생명공학회지
• /
• 제34권4호
• /
• pp.289-298
• /
• 2006

3',5'-cyclic adenosine monophosphate (cAMP) is an important molecule, which mediates diverse cellular processes. For example, it is involved in regulation of sugar uptake/catabolism, DNA replication, cell division, and motility in various acterial species. In addition, cAMP is one of the critical regulators for syntheses of virulence factors in many pathogenic bacteria. It is believed that cAMP acts as a signal for environmental changes as well as a regulatory factor for gene expressions. Therefore, intracellular concentration of cAMP is finely modulated by according to its rates of synthesis (by adenylate cyclase), excretion, and degradation (by cAMP phosphodiesterase). In the present review, we discuss the bacterial physiological characteristics governed by CAMP and the molecular mechanisms for gene regulation by cAMP. Furthermore, the effect of cAMP on phosphotransferase system is addressed.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제6권5호
• /
• pp.337-340
• /
• 2001

A galactooligosaccharide(GalOS)-producing yeast, OE-20 was selected from forty seven strains of yeast growing in Korean traditional Meju (cooked soybean) and the yeast was tentatively identified as Kluyveromyces maxianus var lactis by its morphology and fermentation profile. A maximum yield of 25.1%(w/w) GalOS, which corresponds to 25.1 g of GalOS per liter, was obtained from the reaction of 100 g per liter of lactose solution at 3$0^{\circ}C$, pH 7.0 for 18 h with an intracellular crude $\beta$-galactosidase. Glucose and galactosidase were found to inhibit GalOS formation. The GalOS that were purified by active carbon and celite 545 column chromatography were supplemented in MRS media and a stimulated growth was observed of some intestinal bacteria. In particular the growth rate of Bifidobacterium infantis in the GalOS containing MRS broth increased up to 12.5% compared to that of the MRS-glucose broth during a 48h incubation period.

• 한국동물위생학회지
• /
• 제42권4호
• /
• pp.301-304
• /
• 2019

The objective of this study was to determine the in vitro intracellular and extracellular minimum inhibitory concentrations (MICs) of 13 antimicrobials against one recently isolate Lawsonia intracellularis, the etiological agent of proliferative enteropathy (PE). The final MICs were assessed by counting the number of heavily infected cells (HICs;>30 bacteria per cell) using an immunoperoxidase monolayer assay. Enrofloxacin (InMIC; 1~2 ㎍/mL and ExMIC; 16 ㎍/mL) still presented the most notable antimicrobial susceptibility, and marbofloxacin (2 ㎍/mL and 8 ㎍/mL) was followed. Colistin (0.25 ㎍/mL and 2 ㎍/mL) presented a susceptibility followed by tylvalosin (1 ㎍/mL and 2 ㎍/mL). Florfenicol and lincomycin had the weakest susceptibility and amoxicillin, penicillin G, chlortetracycline, oxytetracycline, tiamulin, tilmicosin, and tylosin displayed weak susceptibility. Although some antibiotics showed decreased susceptibility patterns, they showed similar patterns to recent antibiotic susceptibility patterns in Korea. In addition, these results could be one of contributions in clinical fields.

• Journal of Microbiology and Biotechnology
• /
• 제23권6호
• /
• pp.779-784
• /
• 2013

Leptospirosis is a worldwide zoonosis of global concern caused by Leptospira interrogans. The availability of ligand libraries has facilitated the search for novel drug targets using chemogenomics approaches, compared with the traditional method of drug discovery, which is time consuming and yields few leads with little intracellular information for guiding target selection. Recent subtractive genomics studies have revealed the putative drug targets in peptidoglycan biosynthesis pathways in Leptospira interrogans. Aligand library for the murD ligase enzyme in the peptidoglycan pathway has also been identified. Our approach in this research involves screening of the pre-existing ligand library of murD with related protein family members in the putative drug target assembly in the peptidoglycan biosynthesis pathway. A chemogenomics approach has been implemented here, which involves screening of known ligands of a protein family having analogous domain architecture for identification of leads for existing druggable protein family members. By means of this approach, one murC and one murF inhibitor were identified, providing a platform for developing an anti-leptospirosis drug targeting the peptidoglycan biosynthesis pathway. Given that the peptidoglycan biosynthesis pathway is exclusive to bacteria, the in silico identified mur ligase inhibitors are expected to be broad-spectrum Gram-negative inhibitors if synthesized and tested in in vitro and in vivo assays.

• Journal of Microbiology
• /
• 제45권1호
• /
• pp.29-33
• /
• 2007

Salmonella typhimurium, causing mouse typhoid, infects hosts such as macrophage cells, and proliferates in intracellular vacuoles causing infected cells to trigger numerous genes to respond against the infection. In this study, we tried to identify such genes in RAW264.7 cells by using the PCR screening method with degenerate primers. Fourteen genes were found to be differentially expressed after a 4 h infection in which the expression of 8 genes increased while expression of the others decreased. Most of the genes were involved in proinflammatory responses such as cytokines production and cell death. The mutation in msbB gene encoding the myristoyl transferase in lipid A of lipopolysaccharide (LPS) resulted in much lower toxicity to the inoculated animals. We compared the expression of the identified genes in wild-type and msbB-mutated S. typhimurium infections and found that Lyzs encoding lysozyme type M was differentially expressed. This gene is quite likely to be related to bacterial survival in the host cells.