• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.277-286
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• 2008

This paper deals with the theoretical derivation of the modified Haldane model of the substrate inhibition in the microbial growth processes. Based on the biological concepts of substrate-receptor complex working mechanisms, a new microbial kinetics of N-fold multiplex substrate inhibition and its generalization has been considered theoretically, which is natural expansion of the simple substrate inhibition mechanism in the enzyme reaction. As a result, the modified Haldane model of the substrate inhibition turns out to be a well-designed four-parameter kinetic model with a biological constant of the total substrate inhibition concentration.

• Korean Journal of Environmental Agriculture
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• v.33 no.3
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• pp.194-197
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• 2014

BACKGROUND: Herbal extracts have been screened for their inhibitory effect of seed germination and root development on weeds, but there is a scarcity of reports for crop growth regulation. The objective of this research was to develop a growth inhibitor on Brassica campestris, and its effective extraction method from herbal medicine extract. METHODS AND RESULTS: Eighty four herbal medicine extracts were tested for their plant growth inhibition activity on B. campestris. The alcohol extracts of Artemisia annua, Cinnamomum cassia, and Mentha arvensis inhibited over 30% of germination and the extract of A. annua, and C. cassia inhibited over 70% of radicle growth at 0.1 % w/w treatment. The partially purified extracts of A. annua, and C. cassia with dichloromethane and hexane showed stronger radicle growth inhibition than the crude extracts on B. campestris. The diethyl ether extract of A. annua showed a similar 50% radicle growth inhibition ($RI_{50}$ = 45 mg/L) to its partially purified extract with dichloromethane or hexane, but the diethyl ether extract of C. cassia showed a worse $RI_{50}$ than the purified extract. CONCLUSION: The alcohol extracts of A. annua, and C. cassia showed potent radicle growth inhibition properties on B. campestris. Diethyl ether proved to be a good solvent for simple extraction from A. annua.

• Plant Resources
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• v.3 no.1
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• pp.59-65
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• 2000

The opening process of cut calla flower was faster at 30 t than at lower temperatures as it could be expected from its tropical origin. Gibberellin enhanced the flower opening, however, it also speeded up senescent. Silver thiosulfate was effective in prolonging the vase life of the cut calla flower. Silver thiosulfate reduced ethylene generation by the flower and inhibited microbial growth in the flower stalk. Reduction in ethylene generation and inhibition of microbial growth is thought to be responsible for the extension of the vase life of cut calla flowers by silver thiosulfate.

• Journal of Environmental Health Sciences
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• v.33 no.1 s.94
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• pp.21-29
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• 2007

Paeonia lactiflora was stepwise extracted with hexane, chloroform, ethyl acetate, butanol and water. Anti-microbial activity of each extract was investigated. Methanol extract of P. lactiflora revealed anti-microbial activity against S. mutans, C. albicans, and S. aureus. Also, hexane fraction revealed anti-bacterial activity against S. mutans and ethyl acetate fraction acted as potent anti-microbial agent on C. albicans and S. aureus. The relative growth ratio(RGR) of hexane fraction of P. lactiflora against S. mutans were determined as 77.8% in concentration of 0.125 mg/ml, 98.46% in 0.25 mg/ml and 100% in 0.5 mg/ml. The ethyl acetate fraction of P. lactiflora revealed RGR against C. albicans as 52.5% in concentration of 0.125 mg/ml, 60.83% in 0.25 mg/ml and 78.33% in 0.5 mg/ml. It indicate that increasing concentration increase RGR. The measured minimal inhibitory concentration(MIC) of hexane fraction on S. mutans KCTC 5316 strain was 0.5 mg/ml and MIC of ethyl acetate fraction on C. albicans KCTC 7270 was 2.0 mg/ml. The experiment of inhibition to growth of KB roll(oral squamous cell carcinoma) result 61.9% in butanol, 76.7% in hexane extract of P. lactiflora. The hexane extract exhibit potent inhibition effect to the growth of KB cell. These results suggest that the hexane extract of Paeonia lactiflora has antimicrobial activity against S. mutans and has preventive effect to dental caries in addition to potent inhibition to KB cell growth.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.15 no.2
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• pp.53-79
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• 2002

To screen the effective materials for hair loss treatment, several natural extracts were tested using in vivo and in vitro test models. Firstly, all test materials were applicated onto the back skin of C57BL／6 mouse and then hair growth promoting effect was measured using hair growth index. As a result, Prunus mume, black bean, Brassica campestris subsp. black sesame and Rubi Fructus showed potent hair growth promoting effect, ranking as 1.5-2.0 of hair growth index. However, there were no plant extracts, which have remarkable potential of growth promotion of human hair dermal papilla cells cultured in vitro. In the experiments of 5${\alpha}$-reductase type Ⅱ inhibition assay, Prunus mume, Eriobotryae Folium showed effective potential to inhibit the activity of 5${\alpha}$-reductase type Ⅱ. To investigate the possible involvement of the effect of several plant extracts on the gene expression of growth factors in human hair dermal papilla cells, RT - PCR analyses were performed. However, there were no plant extracts, which have profound effect on the gene expression of several growth factors such as IGF-I, KGF, HGF and VEGF in the dermal papilla cells. Another tests for inhibition of microbial such as P. acne were also carried out to find whether these plant extracts have anti -microbial activities. Rubi Fructus showed anti -microbial effects on Propionibacterium acnes, which is believed as a pathogen of acne. Together, these results showed several plant extracts can be used for hair growth promotion.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.15 no.2
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• pp.80-103
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• 2002

To screen the effective materials for hair loss treatment, several natural extracts were tested using in vivo and in vitro test models. Firstly, all test materials were applicated onto the back skin of C57BL／6 mouse and then hair growth pormoting effect were measured using hair growth index As a result, Polygonum muitifiorum Thunb and Terrninalia chebula Retz. showed potent hair growth promoting effect, ranking as 1.5-2.0 of hair growth index. However, there were no plant extracts, which have remarkable potential of growth promotion of human hair dermal papilla cells cultured in vitro. In the experiments of 5${\alpha}$-reductase type Ⅱ inhibition assay, Morus alba L., Chaenomelis Fructus, Saussureae Radix, Angelicae Gigantis Radix, Polygonum multifiorum Thunb, and Angelica dahurica (Fischer) Bentham et Hooker f. showed effective potential to inhibit the activity of 5${\alpha}$-reductase type Ⅱ. To investigate the possible involvement of effects of several plant extracts on the gene expression of growth factors in human hair dermal papilla cells, RT-PCR analyses were performed. As a consequences, Mentha haplocalyx Briq., Cimicifuga foetida L., Eclipta prostrata (L.) L., Pinus densiflora S. et. Z, and Polygonum muitifiorum Thunb revealed the regulatory roles on the expression of growth factors such as IGF-I, KGF, HGF and VEGF in the dermal papilla cells. Another test for inhibition of microbial such as P. acne and P. ovale were also carried out to find whether these plant extracts have anti-microbial activities. Morus alba L. and Chaenomelis Fructus showed anti-microbial effects on Propionibacterium acnes, which is believed as a pathogen of acne. Together, these results showed several plant extracts can be used for hair growth promotion.

• Journal of Microbiology and Biotechnology
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• v.4 no.3
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• pp.195-199
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• 1994

Immunostimulation effects of the cell wall components isolated from Lactobacillus plantarum were investigated by studying the macrophage s tumorcidal activity, splenocyte proliferation, anticomplementary activity and the inhibition of peritoneal tumor cell growth measured with ICR mice inoculated with sarcoma 180. The immunopotentiating cell wall components were a complex of peptidoglycan and exopolysaccharides. The tumorcidal activity of macrophage against Yacl and B16 tumor cells was enhanced when the cell wall components were added into the macrophage s culture medium. They also stimulated splenocytes to proliferate up to the same level as when the concanavalin A was added into the splenocyte's culture medium. The complementary activity was inhibited by 50% when the cell wall components were incubated with the sheep red blood cells treated with hemolysin and guinea pig complement. This result confirmed that the cell wall components had an antitumor effect, because the anticomplementary activity is usually accompanied by an antitumor activity at the same time. This fact was confirmed again by the inhibition of the growth of sarcoma 180 when the cell wall components were injected intraperitoneally into ICR mice inoculated with sarcoma 180. As a result, it is concluded that the cell wall components isolated from Lactobacillus plantarum had multifunctional immunostimulation effects in vitro and in vivo.

• Preventive Nutrition and Food Science
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• v.17 no.3
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• pp.210-216
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• 2012

The use of suitable sanitizers can increase the quality of fresh-cut produce and reduce the risk of foodborne illnesses. The objective of this study was to compare the washing effects of 100 mg/L sodium hypochlorite (SH) and 500 mg/L acidified sodium chlorite (ASC) on the prevention of enzymatic browning and the growth of microbial populations, including aerobic plate counts, E. coli, and coliforms, throughout storage at $4^{\circ}C$ and $10^{\circ}C$. Fresh-cut zucchini, cucumbers, green bell peppers, and root vegetables such as potatoes, sweet potatoes, carrots, and radishes were used. Compared to SH washing, ASC washing significantly (p<0.05) reduced microbial contamination on the fresh-cut produce and prevented browning of fresh-cut potatoes and sweet potatoes during storage. More effective inhibition of aerobic plate counts and coliforms growth was observed on fresh-cut produce treated with ASC during storage at $10^{\circ}C$. Polyphenol oxidase (PPO) activity of fresh-cut potatoes and sweet potatoes was more effectively inhibited after washing with ASC. The use of 500 mg/L ASC can provide effective antimicrobial and anti-browning treatments of fresh-cut produce, including processed root vegetables.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.428-437
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• 2007

The potential for humic substances to serve as terminal electron acceptors in microbial respiration and the effects of humic substances on microbial azoreduction were investigated. The dissimilatory azoreducing microorganism Shewanella decolorationis S12 was able to conserve energy to support growth from electron transport to humics coupled to the oxidation of various organic substances or $H_2$. Batch experiments suggested that when the concentration of anthraquinone-2-sulfonate (AQS), a humics analog, was lower than 3 mmol/l, azoreduction of strain S12 was accelerated under anaerobic condition. However, there was obvious inhibition to azoreduction when the concentration of the AQS was higher than 5 mmol/l. Another humics analog, anthraquinone-2-sulfonate (AQDS), could still prominently accelerate azoreduction, even when the concentration was up to 12 mmol/l, but the rate of acceleration gradually decreased with the increasing concentration of the AQDS. Toxic experiments revealed that AQS can inhibit growth of strain S12 if the concentration past a critical one, but AQDS had no effect on the metabolism and growth of strain S12 although the concentration was up to 20 mmol/l. These results demonstrated that a low concentration of humic substances not only could serve as the terminal electron acceptors for conserving energy for growth, but also act as redox mediator shuttling electrons for the anaerobic azoreduction by S. decolorationis S12. However, a high concentration of humic substances could inhibit the bacterial azoreduction, resulting on the one hand from the toxic effect on cell metabolism and growth, and on the other hand from competion with azo dyes for electrons as electron acceptor.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.664-671
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• 2006

Modeling the growth kinetics of lactic acid bacteria (LAB), one of the most valuable microbial groups in the food industry, has been actively pursued in order to understand, control, and optimize the relevant fermentation processes. Most modeling approaches have focused on the development of single population models. Primary single population models provide fundamental kinetic information on the proliferation of a primary LAB species, the effects of biological factors on cell inhibition, and the metabolic reactions associated with cell growth. Secondary single population models can evaluate the dependence of primary model parameters, such as the maximum specific growth rate of LAB, on the initial external environmental conditions. This review elucidates some of the most important single population models that are conveniently applicable to the LAB fermentation analyses. Also, a well-defined mixed population model is presented as a valuable tool for assessing potential microbial interactions during fermentation with multiple LAB species.