• Advances in Traditional Medicine
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• v.5 no.4
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• pp.308-315
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• 2005

Aflatoxin contamination is a major problem in several food crops. Aflatoxin, a mycotoxin, produced by Aspergillus flavus has gained immense concern in the scientific world because of its tremendous harmful effects. The study was focused to see the effect of oil and aqueous extract of neem (Azadirachta indica) seeds on the growth of Aspergillus and production of aflatoxin by the mold. Various amounts of neem oil $(5\;-\;50\;{\mu}l/ml)$ and aqueous extract of neem (5 - 50 mg/ml) were used both in the broth as well as the solid medium. Fungistatic (MIC) and minimal fungicidal concentrations (MFC) were found to be $10\;{\mu}l/ml$ and $50\;{\mu}l/ml$ respectively for neem seed oil. At the concentration of $5\;{\mu}l/ml$ neem oil and 5 mg/ml of aqueous extract, a significant decrease in the aflatoxin content was found in broth medium. Aflatoxin production was totally inhibited at $50\;{\mu}l/ml$ and 50 mg/ml for neem oil and aqueous extract of neem respectively, in both treatments. There was significant inhibition of mycelium dry weight by the neem seed oil. Mycelial growth was totally inhibited at $20\;{\mu}l/ml$ of neem seed oil concentration in broth, whereas it was not affected at all by aqueous extract. It can therefore be inferred that the oil and extract from the neem seed leads to inhibition of aflatoxin production while neem seed oil also significantly inhibits the mycelial growth. Neem seed oil thus can be used as potent, natural and easily available anti-aflatoxigenic agent.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.335-343
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• 1992

A Streptomyces strain No. 182-27, which produced amino acid antimetabolite, was isolated from soil. During the course of screening for new amino acid antimetabolites from the culture broths of Actinomycetes, we found that the strain produced a substance active against Gram-positive bacteria and its activity was reversed by L-Ieucine on the synthetic minimal agar medium in the culture broth. The morphological and cultural characteristics serve to identify the producing organism strain 182-27 as the Streptomyces, although the species of this strain should be resolved in further studies. Fermentation was carried out in the synthetic medium at $28^{\circ}C$ for 78 hours. The fermentation yield reached about 2 mg per liter of the broth. Purification was done by ion exchange resin, active carbon, silica gel column chromatography and obtained 20 mg of pure active substance from the 20 $\ell$ culture broth. The 182-27 substance was obtained as white powder, mp 18SoC. From the physicochemical characteristics of the substance, it was amino acid like substance but unknown about its chemical structure. It is active against some Gram-positive bacteria and reversed by L-Ieucine.

• Journal of Microbiology and Biotechnology
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• v.31 no.7
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• pp.999-1010
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• 2021

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment. They are highly toxigenic and carcinogenic. Probiotic bacteria isolated from fermented foods were tested to check their ability to degrade and/or detoxify PAHs. Five probiotic bacteria with distinct morphologies were isolated from a mixture of 26 fermented foods co-cultured with benzo(a)pyrene (BaP) containing Bushnell Haas minimal broth. Among them, B. velezensis (PMC10) significantly reduced the abundance of BaP in the broth. PMC10 completely degraded BaP presented at a lower concentration in broth culture. B. velezensis also showed a clear zone of degradation on a BaP-coated Bushnell Haas agar plate. Gene expression profiling showed significant increases of PAH ring-hydroxylating dioxygenases and 4-hydroxybenzoate 3-monooxygenase genes in B. velezensis in response to BaP treatment. In addtion, both live and heat-killed B. velezensis removed BaP and naphthalene (Nap) from phosphate buffer solution. Live B. velezensis did not show any cytotoxicity to macrophage or human dermal fibroblast cells. Live-cell and cell-free supernatant of B. velezensis showed potential anti-inflammatory effects. Cell-free supernatant and extract of B. velezensis also showed free radical scavenging effects. These results highlight the prospective ability of B. velezensis to biodegrade and remove toxic PAHs from the human body and suggest that the biodegradation of BaP might be regulated by ring-hydroxylating dioxygenase-initiated metabolic pathway.

• YAKHAK HOEJI
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• v.38 no.6
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• pp.742-748
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• 1994

As part of our search for less toxic antimicrobial agents from natural resources, the carpophores of Elfvingia applanata$(P_{ers}.)K_{ARST}.$ was extracted with hot water. EA, the aqueous extract from the carpophores of E. applanata, was lyophilized and a dark brownish powder was obtained. Antimicrobial activity of EA was tested in vitro against Gram positive and Gram negative bacteria by serial broth dilution method, and the antimicrobial activity was expressed by minimal inhibitory concentration(MIC). Among fourteen species of bacteria tested, the antimicrobial activity of EA was the most potent against Proteus vulgaris showing MIC of 1.250 mg/ml. To investigate the effect of antimicrobial combinations of EA with four kinds of antibiotics(ampicillin, cefazolin, oxytetracycline and chloramphenicol), the fractional inhibitory concentration index(FICI) was determined by checkerboard assay for each strain. The antimicrobial combinations of EA with four kinds of antibiotics resulted in synergism in four instances, but no antagonism was observed. Four instances of synergism were observed when EA was combined with ampicillin against Micrococcus luteus, with cefazolin against Bacillus subtilis, with cefazolin against Micrococcus luteus and with oxytetracycline against Staphylococcus aureus.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.90-96
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• 2004

A synthetic defined medium, fortified with amino acids, was developed for the stable production of the kringle fragments of human apolipoprotein(a) (apo(a)), rhLK68. Using a complex rich medium containing yeast extract and a high-cell-density fed-batch culture, the expression level of rhLK68 reached 17% of the total cellular protein, which corresponded to $5\;g\;l^{-1}$ of the culture. To replace the complex media with chemically defined media, several amino acids that positively affect cell growth and gene expression were chosen by a statistical method. The various combinations of the selected amino acids were tested for its fortifying effect on a minimal defined medium. When glutamine only was added, the overall expression level of rhLK68 reached 93% of the complex rich medium increasing the specific expression level by 22.4% and decreasing the cell growth by 24%. Moreover, the addition of glutamine resulted in a 2-fold increase in the concentration of rhLK68 in the culture broth, compared with the minimal defined medium. The synthetic defined media developed in this study could be generally applied to high-cell-density cultures of the recombinant Escherichia coli BL21(DE3), especially for the production of therapeutic proteins that require a strict quality control of the culture media and fermentation processes.

• Journal of Yeungnam Medical Science
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• v.9 no.2
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• pp.396-406
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• 1992

Various susceptibility tests have been used to determine minimal inhibition concentration(MIC) of dermatophytes. They have limitations to apply practically because they need long time to determine MIC. Authors examined MIC of T. rubrum to ketoconazole and itraconazole using 96-well microplate and 24-well macroplate by method of Granade and Artis and tried to check the possibility of this method on clinical application. Nine strains of T. rubrum from patients with dermatophytosis were used. Evaluations of the factors affecting MIC were also tried. The results were as follows. 1. Effect of inoculation density on determination time and MIC : Determination of MIC were possible in 4th days after inoculation at higher inoculation density Caborbance 2.0, 1.0) compared to 6th days at lower inoculation density(absorbance 0.5, 0.25). 2. Effect of incubation temperature on MIC : When incubating at $37^{\circ}C$, MIC were below 0.006-$0.04{\mu}g/ml$ to ketokckonazole and below 0.006-$0.04{\mu}g/ml$ to itraconazole while at $25^{\circ}C$ 0.08-$5.68{\mu}g/ml$ to ketoconazole and 0.006-$0.71{\mu}g/ml$ to itraconazole. Significant reduction of MIC was observed at $37^{\circ}C$ compared to $25^{\circ}C$. 3. Effect of container size on determination time and MIC : When incubating in 96-well microplate and 24-well macroplate, determination of MIC was possible in 4th to 6th days after inoculation in broth-containig 96-well microplate compared to 8th to 12th days in broth-containing 24-well macroplate. But no difference in MIC was observed between different container size. 4. Effect of media on MIC : When using broth as media, MIC were below 0.006-$5.68{\mu}g/ml$ to ketoconazole, below 0.006-$0.36{\mu}g/ml$ to itraconazole in broth-containg 24-well macroplate. When using agar as media, MIC were below 0.006-$5.68{\mu}g/ml$ to ketoconzole, below 0.006-$5.68{\mu}g/ml$ to intraconzole in agar-containing 24-well macroplate. There was slight increase of MIC with agar media compared to broth media. 5. These findings confirm that determination of MIC of dermatophtes by method of Granade and Artis is fast and simple technique for antifungal susceptibility test.

• Microbiology and Biotechnology Letters
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• v.36 no.3
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• pp.215-220
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• 2008

Rahnella aquatilis AY2000 has an unique characteristic which produces an anti-yeast substance (AYS). The AYS of the strain AY2000 was always secreted on agar plate, however, its activity in liquid culture was labile upon storage of the medium. In this paper, cultural conditions of the strain AY2000 for the AYS production were investigated in liquid culture, and minimal inhibitory concentration (MIC) against Saccharomyces cerevisiae was determined for the AYS activity. MIC of the AYS cultured in PYG broth at $^25{\circ}C$ for 24 hr was $23.5{\mu}g/mL$, however, that in MYCS (pH 5.5) broth at the same condition was $15.5{\mu}g/mL$. The activity of the AYS had increased rather in MYCS broth excluded $NH_4$-citrate than in the same broth contained $NH_4$-citrate, and MIC of the AYS produced in MYCS broth without $NH_4$-citrate was $15.5{\mu}g/mL$. When the strain AY2000 was maintained in MYCS broth without $NH_4$-citrate but added $100{\mu}M$ $FeCl_3$, the activity of the AYS had increased and its MIC was $7.8{\mu}g/mL$. MIC of the AYS was $7.8{\mu}g/mL$ after the strain AY2000 was cultured in MYCS broth containing $100{\mu}M$ $FeCl_3$ without $NH_4$-citrate, however, its MIC was $31.3{\mu}g/mL$ after 48-60 hr culture in the same broth.

• Natural Product Sciences
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• v.13 no.1
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• pp.85-89
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• 2007

To determine whether the essential oil from Coriandum sativum and its main component, linalool, exhibit antifungal activity, we employed a broth dilution assay and disk diffusion test using common pathogenic Candida and Trichophyton species. Both coriander oil and linalool significantly inhibited growth of the tested fungi, with minimal inhibitory concentrations (MICs) in the range of $0.03{\sim}2mg/ml$. Furthermore, in a checkerboard titer test, both the oil fraction and linalool exhibited synergism when combined with ketoconazole, with resultant FICIs ranging from 0.06 to 0.53. Notably, hyphal formation in C. albicans cells was obviously inhibited by C. sativum essential oil in this experiment.

• Natural Product Sciences
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• v.11 no.2
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• pp.92-96
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• 2005

The antifungal activities of essential oils from the leaves of Glehnia littoralis, which is cultivated in Korea, were evaluated against pathogenic Trichophyton species by the broth dilution method and the disk diffusion test. Additionally, the effects of the oils together with ketoconazole were tested by the checkerboard titer test. The essential oil fraction and its main components showed significant inhibition of the tested Trichophyton fungi, with minimal inhibitor concentrations (MICs) in the range of 16-32 mg/ml. The results suggest that activities of this oil are based mainly on the contents of ${\alpha}-pinene$ (22.17%), the next prominent component of the oil fraction, while the first main components ${\beta}-pinene$ (57.83%) have relatively mild activity. The MICs of ${\alpha}-pinene$ and ${\beta}-pinene$ were 1-4 mg/ml and 4-32 mg/ml, respectively. Additionally the Glehnia oil fraction and its main components as well, exhibited significant synergism with ketoconazole against Trichophyton rubrum.

• Archives of Pharmacal Research
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• v.26 no.5
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• pp.389-393
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• 2003

The essential oils from Cedrus atlantica, Styrax tonkinensis, Juniperus communis, Lavandula angustifolia, Melaleuca alternifolia, Pelargonium graveolens, Pogestemon patchouli and Rosmarinus officinalis were analyzed by GC-MS. Antifungal activities of the oils were investigated by disk diffusion assay and the broth dilution method against Aspergillus niger and A. flavus. The effects of geraniol and the essential oil fraction from P. graveolens on the antifungal activity of amphotericin Band ketoconazole were examined using a checkerboard microtiter assay against both Aspergillus fungi. Most of the tested essential oils, with the exception of C. atlantica, J. communis, and P. patchouli, significantly inhibited growth of A. niger and to a lesser extent that of A. fIavus, with MICs (minimal inhibitory concentrations) in the range 0.78-12.5 mg/mL. The essential oil fraction of P. graveolens and its main components, geraniol and citronellol, exhibited additive effects with amphotericin B and with ketoconazole against both Aspergillus species, resulting in fractional inhibitory concentration (FIC) indices ranging from 0.52 to 1.00.