• Korean Journal of Microbiology
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• v.52 no.2
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• pp.226-229
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• 2016

The growth of two different fungal species, human pathogenic Cryptococcus neoformans and plant pathogenic Alternaria alternata were inhibited by a chitinase (Chi2) expressed in the autolysing tissue of Coprinellus congregatus. The cell wall thickness was reduced (up to 32%) in C. neoformans compared with that of normal cell, and polysaccharide fibers located outside of the cell wall were also severely removed. The hyphal growth of A. alternata on agar plate was stopped by the enzyme. The allergic inflammation induced by A. alternata was reduced by the enzyme reaction when compared with untreated control in a mouse model.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1582-1589
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• 2009

Bacterial UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) catalyzes the transfer of enolpyruvate from phosphoenolpyruvate (PEP) to uridine diphospho-N-acetylglucosamine (UNAG), which is the first step of bacterial cell wall synthesis. We identified thimerosal, thiram, and ebselen as effective inhibitors of Haemophilus influenzae MurA by screening a chemical library that consisted of a wide range of bioactive compounds. When MurA was preincubated with these inhibitors, their 50% inhibitory concentrations ($IC_{50}s$) were found to range from 0.1 to $0.7\;{\mu}M$. In particular, thimerosal suppressed the growth of several different Gram-negative bacteria such as Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium at a concentration range of $1-2\;{\mu}g/ml$. These inhibitors covalently modified the cysteine residue near the active site of MurA. This modification changed the open conformation of MurA to a more closed configuration, which may have prevented the necessary conformational change from occurring during the enzyme reaction.

• Journal of Plant Biology
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• v.34 no.4
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• pp.261-266
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• 1991

The hairy root was induced form potato tuber disc by infection of a. rhizogenes. The detection of the agropine and mannopine by paper electrophoresis confirmed that induced hairy root was transformed by A. rhizogenes. The activity of peroxidase was the highest at 5 weeks and isozyme pattern of peroxidase revealed 3 cathodic bands and 2 anodic bands and new C4 band(pI 4.6) was observed at 7 weeks after cultivation in hairy root was isoelectric focusing. To study the effect of Ca2+ on cell wall formation in hairy root, channel blocker of Ca2+ was treated. The activity of $\beta$-glucan synthetase II(GS II) related to cell wall synthesis was inhibited by about 50% in diltiazem and flunarizine treatment than that of control, but stimulated in CaCl2 treatment. Therefore these results showed that Ca2+ might be an effective factor in the cell wall formation. The activity of GS II by NaF treatment was increased by about 30%. This result suggested that the activity GS II is changed through phosphorylation process.

• Journal of Microbiology and Biotechnology
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• v.30 no.12
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• pp.1827-1834
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• 2020

Candida albicans is a major fungal pathogen in humans. In our previous study, we reported that an ethanol extract from Aucklandia lappa weakens C. albicans cell wall by inhibiting synthesis or assembly of both (1,3)-β-D-glucan polymers and chitin. In the current study, we found that the extract is involved in permeabilization of C. albicans cell membranes. While uptake of ethidium bromide (EtBr) was 3.0% in control cells, it increased to 7.4% for 30 min in the presence of the A. lappa ethanol extract at its minimal inhibitory concentration (MIC), 0.78 mg/ml, compared to uptake by heat-killed cells. Besides, leakage of DNA and proteins was observed in A. lappa-treated C. albicans cells. The increased uptake of EtBr and leakage of cellular materials suggest that A. lappa ethanol extract induced functional changes in C. albicans cell membranes. Incorporation of diphenylhexatriene (DPH) into membranes in the A. lappa-treated C. albicans cells at its MIC decreased to 84.8%, after 60 min of incubation, compared with that of the controls, indicate that there was a change in membrane dynamics. Moreover, the anticandidal effect of the A. lappa ethanol extract was enhanced at a growth temperature of 40℃ compared to that at 35℃. The above data suggest that the antifungal activity of the A. lappa ethanol extract against C. albicans is associated with synergistic action of membrane permeabilization due to changes in membrane dynamics and cell wall damage caused by reduced formation of (1,3)-β-D-glucan and chitin.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.1039-1050
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• 2010

Carrot is one of the useful crops used abundantly in cooking in Western as well as Asia regions such as China and Korea. However, seed coats have hairs which should be removed to increase germination rate. Furthermore, because of seed hairs, farmers face several additional losses, such as time consumption, manpower, capital and so on, for seed handling. To prevent these problems, study of gene related hair formation using short-hair seed lines is required. We analyzed genes related to hair formation from seed through expressed sequenced tag (EST) profiling, based on the fact that the development of carrot seed hair is related to cellulose synthesis pathway in secondary cell wall synthesis stage. To study the gene expression related to hair formation of the carrot seed, a cDNA library was constructed by using the early maturation stage of the short-hair line (659-1) and hairy seed line (677-14). In short-hair (659-1) and hairy seed (677-14) lines, results from of EST profiling through BLASTX search analysis using the NCBI database showed that 172 and 224 unigenes had significant homology with known protein sequences, whereas 233 and 192 unigenes were not, respectively. All ESTs were grouped into 16 categories according to their putative functions. Twenty nine unigenes among all ESTs were considered to be genes regulating seed hair development from cellulose synthesis pathway during secondary cell wall synthesis stage; in results, 14 unigenes related to seed hair development were found only in hairy seed line.

• Journal of Life Science
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• v.2 no.4
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• pp.232-239
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• 1992

UDP_GlcNAc is metabolized to form vegetative cell wall, cortical peptidoglycans, and outermost layer consisting of galactosamine-6-phosphate ploysaccharide in life cycle of Bacillus megaterium. To obtain a better understanding of the UDP-GlcNAc regulation, we examined the activity of the common first enzyme for the synthesis of nucleotide precursors of peptidoglycans, enoylpyruvate transferase by newly developed method. Both the specific and the total activity decreased after the end of exponential growth followed by and increase from t5 but decreased again parallel to the appearance of the activity of UDP_GlcNAc-4-epimerase. Antibody specificity to anti-transferase IgG and the elution profile on DEAE-Sepharose revealed that B. megaterium has at least two enoylpyruvate transferase isozymes, and UDP_GlcNAc was metabolized to vegetative cell wall and cortical peptidoglycan by each isozme in exponential growth and in sporulation, respectively in life cycle.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.88-95
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• 2013

Candida biofilms are self-organized microbial communities growing on the surfaces of host tissues and medical devices. These biofilms have been displaying increasing resistance against conventional antifungal agents. The roots of Scutellaria baicalensis have been widely used for medicinal purpose throughout East Asia. The aim of the present study was to evaluate the effect of S. baicalensis aqueous extract upon the preformed biofilms of 10 clinical C. albicans isolates, and assess the mechanism of the antibiofilm activity. Its effect on preformed biofilm was judged using an XTT reduction assay and the metabolic activity of all tested strains were reduced ($57.7{\pm}17.3$%) at MIC values. The S. baicalenis extract inhibited (1, 3)-${\beta}$-D-glucan synthase activity. The effect of S. baicalensis on the morphology of C. albicans was related to the changes in growth caused by inhibiting glucan synthesis; most cells were round and swollen, and cell walls were densely stained or ruptured. The anticandidal activity was fungicidal, and the extract also arrested C. albicans cells at $G_0/G_1$. The data suggest that S. baicalensis has multiple fatal effects on target fungi, which ultimately result in cell wall disruption and killing by inhibiting (1, 3)-${\beta}$-D-glucan synthesis. Therefore, S. baicalensis holds great promise for use in treating and eliminating biofilm-associated Candida infections.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.4
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• pp.619-622
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• 1993

Rumen bacterial amino acids in sheep on urea diet were monitored to assess a possible change in amino acid synthesis as a long term response to high rumen ammonia environment. A sheep was fed a semipurified diet with soybean meal, followed by a diet with urea as a main nitrogen source. Mixed rumen bacteria were harvested from ruminal fluid taken 3 h after feeding (twice in soybean meal feeding and 6 times in urea feeding) and fractionated as cell wall, proteins and protein-free cell supernatant of monitor amino acids in each fraction. Ruminal ammonia concentration at the sampling ranged from 5.7 to 39.5 mgN/dl. Cell wall and protein fractions of mixed rumen bacteria were stable in their amino acid composition regardless of nitrogen sources of diet and the feeding duration. However, protein-free cell supernatant fraction showed a higher alanine proportion with urea feeding (18.6 and 28.2 molar % of alanine for samples from sheep fed soybean meal and urea, respectively) and its duration (20.6 and 32.9 molar % for samples from sheep on urea diet for 1 and 65 days, respectively). Total free amino acid level of bacteria was depressed in the initial period of urea feeding but restored on 65th day of the feeding. These results suggest that an alanine synthesizing system may develop in rumen bacteria as urea feeding becomes longer.

• Journal of Microbiology
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• v.43 no.5
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• pp.398-405
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• 2005

Polyamines such as putrescine are small, ubiquitous polycationic molecules that are required for optimal growth of eukaryotic and prokaryotic cells. These molecules have diverse effects on cell physiology and their intracellular content is regulated by de novo synthesis and uptake from the environment. The studies presented here examined the structure of a putative polyamine transporter (Pot) operon in Streptococcus pneumoniae (pneumococcus) and growth of pneumococci in medium containing putrescine substituted for choline. RT-PCR experiments demonstrated that the four genes encoding the Pot system are co-transcribed with murB, a gene involved in an intermediary step of peptidoglycan synthesis. Pneumococci grown in chemically-defined media (CDM) containing putrescine without choline enter logarithmic phase growth after 36-48 hs. However, culture density at stationary phase eventually reaches that of choline-containing medium. Cells grown in CDM-putrescine formed abnormally elongated chains in which the daughter cells failed to separate and the choline-binding protein PspA was no longer cell-associated. Experiments with CDM containing radiolabeled putrescine demonstrated that pneumococci concentrate this polyamine in cell walls. These data suggest that pneumococci can replicate without choline if putrescine is available and this polyamine may substitute for aminoalcohols in the cell wall teichoic acids.

• The Korean Journal of Pharmacology
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• v.25 no.1
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• pp.109-113
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• 1989

Human neutrophil elastase (HNE, EC 3, 4 21, 11), a major causative factor in the induction of pulmonary emphysema, were purified by two steps of liquid chromatography. Purified elastases were cross-reacted with antibody to human neutrophil elastases. Methicillin and cefamandole, which are known as inhibitors of cell wall synthesis of microorganisms, could inhibit the activity of human neutrophil elastase up to 50% with 10mM of both agents and $IC_{50}$ of methicillin was 9.8 mM. Gentamicin, one of the aminoglycosides, also inhibits human neutrophil elastases up to 60% of original activity with 10 mM of this agent and $IC_{50}$ was 9.0 mM. We could demonstrate similar effects in oxytetracycline. 10 mM of oxytetracycline inhibited 95% of human neutrophil elastase and $IC_{50}$ was 0.3 mM. Overall, oxytetracycline, cefamandole and methicillin are strong inhibitors of human neutrophil elastase, and they could be a drug of cholice for the diseases which were known as pathogenesis related to elastase. We also suggest that the mechanism of action of these antibitics are different from the mechanism of antimicrobial effects like inhibition of both cell wall synthesis and protein synthesis.