• Bulletin of the Korean Chemical Society
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• v.24 no.12
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• pp.1859-1861
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• 2003

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.135-139
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• 2006

Most bacteria form biofilm as self-defence system, making efficient food sanitization, preservation, and instrument washing more difficult. Biofilm formation of Salmonella, E. coli, B. cereus, and S. aureus was observed during 24 hr food preservations by performing microtiter plate and glass wool assays. Most cells formed biofilm and attached onto glass wool. When biofilm formation and injury were analyzed on the microtiter plate, 10 and 20% acid-injured E. coli and S. aureus, respectively, 30-50% cold temperature $(4^{\circ}C)-injured$ B. cereus and E. coli, and 30-55% 6% sodium chloride solution-injured Salmonella showed significant biofilm formation. Results indicate biofilm formation level differed within species depending on type of stress.

• The Korean Journal of Pesticide Science
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• v.3 no.3
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• pp.37-44
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• 1999

Two sulphamide (dichlofluanid and tolylfluanid) and three dicarboximide fungicides (iprodione, vinclozolin, procymidone) were used to investigate the correlation between in vitro antifungal activities and in vivo disease controlling activities against Botrytis cinerea, a causal agent of tomato gray mold and to develop efficient in vitro assays. They controlled effectively the development of tomato gray mold disease in vivo and their controlling activities were similar one another. However, several in vitro assays revealed that their in vitro antifungal activities were quite different between sulphamide and dicarboximide fungicides; the formers showed stronger inhibition activities for spore germination than the latters, whereas the formers inhibited mycelial growth less severely than the latters. The results indicate that the fungicides having different modes of action can show different in vitro antifungal activities according to in vitro assays, even if they have similar in vivo disease controlling activities. On the other hand, two rapid and efficient in vitro assays named Microtiter plate methods I (MPM I) and II (MPM II) were developed for the evaluation of fungicides for inhibitory activities against spore germination and mycelial growth of B. cinerea, respectively. The antifungal activities of five fungicides of two chemical groups in MPM I and II were correlated with the inhibitory activities against spore germination and mycelial growth using solid media, respectively.

• The Korean Journal of Pesticide Science
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• v.7 no.3
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• pp.159-168
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• 2003

With microtiter plate, the assay method was developed for detecting the fungicidal activity of new compounds against spore germination, spore adhesion and mycelial growth of Colletotrichum sp. JC24 cal1Sing red pepper anthracnose. Also, the effects of some commercialized fungicides on fungal development like above mentioned were investigated by measuring the optical density of mycelia grown into wells of microtiter plate. For the standardization of assay method, some factors, such as the treatment of MTT and/or propanol, inodulum density and incubation period, affecting on mycelial optical density were investigated. For obtaining precise and consistent mycelial optical density, it was necessary the treatment of MTT for 12 hrs and propanol for 1 hr. inoculum density adjusted to $1\times10^5$ spores/mL and incubation period for 36 hrs at $25^{\circ}C$. For fungicidal activities, 6 protective fungicides, 6 ones inhibiting sterol biosynthesis, and one inhibiting respiration were used in this study. While mancozeb, chlorothalonil and dithianon among 6 protective fungicides inhibited strongly spore germination, adhesion, and mycelial growth at $6.25{\mu}g/mL$, propineb, iminoctadine and fluazinam inhibited intermediately spore germination and mycelial growth at $100{\mu}g/mL$. Washing above 3 fungicides with new PD broth, their activity against spore adhesion decreased. With hexaconazole, tebuconazole and myclobutanil, the tendency of the activity against fungal differentiation of the early infection stage was similar to the latter group of protective fungicides, showing the decrease of the inhibitory activity against spore adhesion by washing 2 hrs after incubation. However, kresoxim-methyl inhibited spore adhesion distinctly, depending on the applied concentrations. Based on these results, it might be able to assess the fungicidal activity of many compounds against spore germination, adhesion and mycelial growth by the use of microtiter plate in vitro. Using the assay developed in this report, it was possible to investigate the inhibitory activity of some commercialized fungicides, too.

• KSBB Journal
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• v.24 no.1
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• pp.106-112
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• 2009

An optical sensing membrane has been fabricated to measure the concentration of dissolved oxygen(DO) and pH value simultaneously. It has employed HPTS as a pH sensitive dye and a ruthenium(II) complex as a DO sensitive dye. The sensing membrane has been applied to wells in a 24-well microtiter plate. Using the 24-well microtiter plate the concentrations of dissolved oxygen and pH values have been on-line monitored during the cultivations of E.coli DH5${\alpha}$, B.cereus 318 and P.pastoris X-33. On-line monitoring of DO and pH in microorganism cultivation processes showed good performance of the sensing membrane containing 5 mM HPTS and 2 or 5 mg/mL Rudpp.

• The Korean Journal of Pesticide Science
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• v.11 no.1
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• pp.18-26
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• 2007

Fungicidal screening was performed to control soybean black root rot caused by Calonectria ilicicola through in vitro and greenhouse assays. In in vitro assay, 25 fungicides were assessed by an agar dilution method and a 96-well microtiter plate method. While protective fungicides including dithianon, dichlofluanid, mancozeb, and captan showed a very low activity against the mycelial growth C. ilicicola SC03-15 in the agar dilution method, they displayed potent inhibitory activity against spore germination in a 96-well microtiter plate method with $EC_{50}$ values of 4.65, 0.61, 4.64, and $0.29{\mu}g\;mL^{-1}$, respectively. Ergosterol biosynthesis-inhibiting (EBI) fungicides showed different antifungal activity against mycelial growth and spore germination according to molecules. Difenconazole displayed higher antifungal activity against spore germination rather than mycelial growth, and prochloraz inhibited potently both mycelial growth and spore germination with EC50 values less than $1.8{\mu}g\;ml^{-1}$. In contrast, the other EBI fungicides inhibited more highly mycelial growth than spore germination. Carbendazim+diethofencarb and dazomet also inhibited both mycelial growth and spore germination of C. ilicicola SC03-15 at very low concentrations. In greenhouse assay, carbendazim+diethofencarb effectively controlled a soybean black root rot by drenching 2 days before or after inoculation. In addition, tebuconazole showed potent curative activity against soybean black root rot.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.101-111
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• 2017

The task of improving a fungal strain is highly time-consuming due to the requirement of a large number of flasks in order to obtain a library with enough diversity. In addition, fermentations (particularly those for fungal cells) are typically performed in high-volume (100-250 ml) shake-flasks. In this study, for large and rapid screening of itaconic acid (IA) high-yielding mutants of Aspergillus terreus, a miniaturized culture method was developed using 12-well and 24-well microtiter plates (MTPs, working volume = 1-2 ml). These miniaturized MTP fermentations were successful, only when highly filamentous forms were induced in the growth cultures. Under these conditions, loose-pelleted morphologies of optimum sizes (less than 0.5 mm in diameter) were casually induced in the MTP production cultures, which turned out to be the prerequisite for the active IA biosynthesis by the mutated strains in the miniaturized fermentations. Another crucial factor for successful MTP fermentation was to supply an optimal amount of dissolved oxygen into the fermentation broth through increasing the agitation speed (240 rpm) and reducing the working volume (1 ml) of each 24-well microtiter plate. Notably, almost identical fermentation physiologies resulted in the 250 ml shake-flasks, as well as in the 12-well and 24-well MTP cultures conducted under the respective optimum conditions, as expressed in terms of the distribution of IA productivity of each mutant. These results reveal that MTP cultures could be considered as viable alternatives for the labor-intensive shake-flask fermentations even for filamentous fungal cells, leading to the rapid development of IA high-yield mutant strains.

• BMB Reports
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• v.43 no.7
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• pp.468-473
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• 2010

Previously, various inhibitors of cell wall synthesis induced the drp35 gene of Staphylococcus aureus efficiently. To determine whether drp35 could be exploited in antistaphylococcal drug discovery, we cloned the promoter of drp35 ($P_d$) and developed different biological assay systems using an engineered S. aureus strain that harbors a chromosomally-integrated $P_d$ - lacZ transcriptional fusion. An agarose-based assay showed that $P_d$ is induced not only by the cell wall-affecting antibiotics but also by rifampicin and ciprofloxacin. In contrast, a liquid medium-based assay revealed the induction of $P_d$ specifically by the cell wall-affecting antibiotics. Induction of $P_d$ by sublethal concentrations of cell wall-affecting antibiotics was even assessable in a microtiter plate assay format, indicating that this assay system could be potentially used for high-throughput screening of new cell wall-inhibiting compounds.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.1
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• pp.115-118
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• 1996

The study on the cytotoxicities of heavy metals, metal-metal and metal-chelator combinations was carried out to evaluate the cytotoxic effect of those on mouse L929 fibroblasts. The colorimetric assays (NR and MTT) were conveniently carried out in 96-well microtiter plates. The rank order was Cd > Zn Ni > Cr(III) for the heavy metals tested. Examination of the effect of metal-metal interaction on cytotoxicity showed a moderate reduction of cadmium toxicity by zinc. The colorimetric assays were also effectively used to investigate the effect of the chelators, ethylenediamine tetra acetic acid (EDTA) and chitosan. Reduction of heavy metal toxixity by chelator was efficient.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.482-482
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• 2005